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BACKGROUND OF THE DISCLOSURE
After an oil well has been partly drilled and suspected producing formations have been penetrated, it is necessary to make various tests to determine production possibilities of various formations. One of the test techniques involves the use of a tool which is known as a formation tester. An exemplary formation tester is set forth in U.S. Pat. Nos. 4,375,164 and 4,593,560 assigned to assignee of the present disclosure. As set forth in those disclosures, the tool is adapted to be lowered into the well bore, supported on an armored logging cable enclosing certain conductors for providing surface control for the tool. The logging cable extends to the surface and passes over a sheave and is spooled on a reel or drum. The conductors in it connect with suitable surface located power supplies, controls, and recorder. The formation tester is lowered to a specified depth in a well. At that elevation, a backup shoe is extended on one side of the formation tester and formation testing apparatus is extended diametrically opposite into the formation of interest. The equipment so extended normally includes a surrounding elastomeric sealing pad which encircles a smaller extendable snorkel which penetrates a formation as the formation will permit, up to a specified depth. The snorkel is ideally isolated from fluid and pressure in the well to be able to test the formation. The snorkel is extended into the formation to enable direct fluid communication from the formation into the tool. Moreover, it is isolated from invasion of the well borehole fluid and pressures therein to permit a pressure sensor to obtain formation pressure. Further, a sampling chamber elsewhere in the formation tester can be selectively connected through the snorkel by suitable valves to obtain delivery of a fluid sample from the formation. The fluid sample typically may include a relatively small sample which is a pretest sample, and if that is acceptable, a larger sample can be drawn through the snorkel. Various pretest and sample volumes are selected and determined under control from the surface.
Testing procedures require a substantial interval. For instance, isolation steps must be undertaken to assure that the formation tester properly obtains data from a single formation without invasion of other well fluids from different strata. These procedures involve extension and retraction of the packer and snorkel described above. These steps are normally accompanied by the extension of certain backup shoes which set backup shoes on the opposite side of the formation tester in the borehole. Thus, the references noted above describe apparatus which extends the snorkel on one side of the tool body and which extend backup pistons on the opposite side to assure that adequate force is delivered to position the snorkel in the formation of interest.
These procedures require some time to execute. Delay is costly in the performance of such downhole test procedures and equipment. The delay that is encountered in performing such tests translates into added cost. While the cost of rental of a formation tester can be negligible, a far greater cost is the rig time involved during which time the testing procedures are carried out. Ideally, test procedures are conducted as rapidly as possible to assure that the tests are conducted at a minimum cost. As a practical matter, rig time is an increment of cost which can substantially exceed the cost of rental of a formation tester. For these reasons, it is desirable that the formation tester operate as rapidly as possible.
One of the steps carried out by the formation tester is extension of the snorkel and surrounding pad which achieves a seal to isolate the formation. Additionally, backup pistons are extended, thereby assuring that backup shoes are anchored in the well borehole. After this equipment has been extended and after the formation test procedure has ended, the extended equipment is retracted. The snorkel is pulled in and the seal around the elastomeric gasket is normally broken. The backup shoes extended on the opposite side of the testing tool are also retracted.
The present invention is directed to an improved system including a hydraulic circuit within the formation tester which assures that the foregoing movements are carried out as rapidly as possible. That is, the formation testing apparatus is extended and retracted as quickly as possible. This improved apparatus provides a means and mechanism whereby more rapid extension is obtained. This cuts down on the time in which the formation tester is in the borehole. This thereby reduces the test duration and reduces rig time costs. This also reduces the possibility of sticking. It also assures that the extended and retracted equipment is quickly and properly seated to be subsequently retracted. With the foregoing in view, the present apparatus is summarized as a valving system including solenoid valves cooperative with a speed-up mechanism thereby assisting rapid operation of the equipment in the formation tester. Extension of the apparatus is speeded up so that the formation tester can be moved as quickly as possible from location. Further objects and advantages of the present disclosure will become more readily apparent upon consideration of the description of the preferred embodiment set forth below in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.
It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
FIG. 1 shows a formation tester suspended in a well borehole for conducting formation tests wherein a snorkel is extended into the formation and backup shoes support the formation tester during the test and further including a tool hydraulic system for operation;
FIG. 2 is a hydraulic schematic showing the improved hydraulic circuit for use in the formation tester of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Attention is first directed to FIG. 1 of the drawings where the numeral 10 identifies a formation tester constructed in accordance with the teaching of this disclosure. It is supported in a well borehole 12 which is shown to be open hole. The tool 10 typically operates by testing a formation penetrated by open borehole and to this end, no casing has been shown in FIG. 1. Typically, the well is filled with drilling fluid which is known as drilling mud, and the column of drilling mud is identified at 14. The formation tester 10 comprises an elongate cylindrical body of substantial length and weight. It is supported on an armored cable known as a well logging cable. Suitable electrical conductors are enclosed in the cable, the cable being identified by the numeral 16. The cable extends to the surface and passes over a sheave 18. The cable 16 is stored on a drum 20. The cable might be several thousand feet in length to test formations at great depths. Conductors from the cable 16 are connected with various and sundry controls identified at 22. The electronic control equipment and the formation tester are provided with power from a power supply 24. The signals and data obtained from the formation tester 10 are output through the surface located equipment and to a recorder 26. The recorder records the data as a function of depth. An electronic or mechanical depth indicating mechanism is connected to the sheeve 18 and provides depth measurement to the recorder 26 and is thus identified by the numeral 28.
Referring now the tool body, it will be first observed that it supports a laterally extending probe which is identified by the numeral 30. The probe 30 is supported to extend from the tool body. The extended probe is surrounded by a ring of elastomeric material 32. The ring 32 is a seal pad. It is pliable, and is affixed to the probe 30 for sealing operation. Moreover, the ring 32 operates as a seal when pressed against the adjacent formation. Assume the formation 34 adjacent to the tool is suspected to have fluids of interest. This formation 34 is tested by extending a snorkel 36 into the formation. The probe 30 is extended against the formation. When the seal 32 is pressed against the formation 34, the seal prevents invasion of open hole pressure or drilling fluids into the vicinity of the extended snorkel 36. It is important to isolate the snorkel tip from the invading fluids or pressure so that data obtained from the formation 34 is unmodified by the intrusion of a well borehole.
This sequence of operation involving extension of the snorkel 36 into the formation typically occurs after backup shoes and the sealing pad are positioned, and an equalizing valve in the tester is closed. The numeral 38 identifies a top backup shoe which is supported on a piston rod 40. The piston rod 40 extends diametrically opposite the snorkel 36. The snorkel 36 extends on one side of the tool body while the backup shoe is on the opposite side. The piston rod 40 which supports the backup shoe is connected with a piston 42 in a hydraulic cylinder 44. The cylinder is preferably provided with hydraulic for from both ends so that the piston 42 is double acting; that is, the piston rod 40 is extended under power and retracted under power. As will be observed, the backup shoe 38 is above the snorkel 36. A similar backup shoe 48 is also included below the snorkel. Preferably, the backup shoes 38 and 48 are evenly spaced above and below the snorkel 36. Moreover, they are operated by hydraulic power simultaneously applied for extension of the probe 30. This assures that the seal 32 has loading on it to achieve the pressure seal to prevent intrusion of well fluids and pressure into the formation 34. The backup shoe 48 is supported on a similar piston rod and operates in the same fashion, preferably being connected and a parallel with the other backup shoe so that the two operate together.
Attention is now directed to FIG. 2 of the drawings where the numeral 50 identifies the tool hydraulic system. This is carried within the body of the formation tester 10 and operates the equipment partially illustrated in FIG. 1. The hydraulic system 50 incorporates a reservoir 52 which also serves as a return sump. A compensating piston 54 is fluidly communicated with the exterior to convert external pressure into pressure applied to the fluid in the reservoir 52. This establishes the minimum pressure in the hydraulic system. The apparatus further includes a motor 56 which operates a pump 58 for hydraulic fluid. The fluid is delivered over an outlet line 60 and is provided to a first solenoid valve 62 and to a second solenoid valve 64. The valves 62 and 64 are preferably identical and are described as three-way, normally closed valves. The system also includes a high pressure relief valve 66 which has a spring setting which determines the pressure at which pressure is dumped from the line 60.
The solenoid valves 62 and 64 are identical in construction. The valve 62 will be described as the supply valve while the valve 64 will be described as the retraction valve. The logic behind these definitions will be understood more readily hereinafter.
The numeral 68 identifies a priority valve. It operates in conjunction with a fluid multiplier 70. The fluid multiplier 70 includes certain components and check valves to be described. Briefly, it is a movable piston 72 which has a first surface area at the upper end identified at 74. The piston is enlarged and at the opposite end has a surface area which is much greater. The piston has an intermediate step and the step area is identified at 76. The areas 74 and 76 (when added together) equal the surface area 78 at the opposite end. The fluid multiplier 70 has an outlet line 82. The outlet line delivers an increased volume of fluid in the fashion to be described. The cylinder 80 is constructed with uniform diameter along the full length thereof except the very upper end where the diameter is larger; the larger inside diameter forms a fluid bypass from the face 78 to the face 76 to quickly dump fluid around the piston at the end of the upward stroke.
The piston 72 is drilled with an internal passage and a check valve 84 connects across the step. It is constructed with a specific flow direction. It delivers fluid to the lower part of the fluid multiplier.
The supply valve 62 connects to the small end of the fluid multiplier. Additionally, a check valve 86 is connected across the priority valve 68 for flow in a particular direction. In fact, the check valve 86 can deliver flow from the intermediate chamber in the fluid multiplier. Likewise there is an additional check valve 88 connected from the sump. It connects to the intermediate region of the fluid multiplier.
As further shown in FIG. 2 of the drawings, the line 82 extends to a first hydraulic means 90 for extending the probe 30. A second and identical hydraulic means 92 is also included. They are spaced from one another to assure that the probe extends evenly. Moreover, they provide adequate extension and power for fastening the probe into the formation. In like fashion, the cylinder and piston arrangement at 90 is connected and parallel with the cylinder 44 for operation. A duplicate of this is provided for the backup shoe 48. Thus, the hydraulic means 92 is parallel to a similar hydraulic mechanism 94 which extends the backup shoe 48. The setting line 82 is input to one side as illustrated in FIG. 2, thereby causing extension. In similar fashion, a retraction line 98 is connected between the various hydraulic means at 96, and extends to the retraction valve 64. This enables fluid to be returned to sump.
OPERATION OF THE PREFERRED EMBODIMENT
While the foregoing describes the arrangement of the hydraulic schematic shown in FIG. 2, better understanding will be obtained on a review of the sequence of operation. Assume that the formation tester shown in FIG. 1 had been lowered to a formation which is to be tested. At this point, this equipment is operated in the following fashion. Assume that pressure within the borehole is a specified established level determined by the mud column in the borehole. This acts through the compensating piston 54 shown in FIG. 2. The motor 56 is operated which in turn operates the pump 58 and delivers hydraulic fluid under pressure through the line 60. The valve 62 is then operated by suitable signals provided to the solenoid valves and high pressure hydraulic fluid is delivered to the priority valve 68. The fluid is also delivered to the fluid multiplier 70. The influx of fluid under pressure into the small chamber adjacent to the relatively small piston area 74 starts the piston 72 moving. Because there is a difference in surface areas, a small stroke of the piston 72 results in a large volumetric flow of hydraulic fluid through the setting line 82. This is delivered with a sufficient volumetric flow that rapid extension of the means 90, 92, 94 and 44 are accomplished. This assures prompt setting of the probe 30 and the backup shoes 38 and 48 which operate in response to the common delivery of hydraulic fluid under pressure from the fluid multiplier 70. Moreover, when fluid is delivered to the small piston face 74 and exceeds a required value, pressure fluid is then additionally delivered through the priority valve. This pressure change is observed at the intermediate area within the cylinder and acts on the face 76. There is the possibility that a fluid pressure reduction is initially observed above the piston face 76. If that occurs, fluid is delivered through the check valve 88. Recall that the initial pressure is delivered to the small face 74. The check valve 88 thus helps deliver more fluid from the pressure compensated hydraulic reservoir system. This assures that reduced pressure is not sustained in this region.
As will be observed, an initial force is applied to the small face 74. The piston drives the larger face 78. The priority valve experiences something of a reduced pressure and does not open at the time that pressure is first applied to the face 74 of the piston 72. As the probe 30 extends and encounters greater resistance, pressure increases in the setting line 82 which is reflected back to the smaller sides of the piston 72. Thus, pressure observed at the priority valve increases markedly and the priority valve is then forced open. When it opens, it delivers fluid to the intermediate face 76. In other words, high pressure is now delivered to the face 76 and the double faced piston 72 is then exposed to a common pressure on both faces 74 and 76. This assures that the final pressure applied through the setting line is the maximum pressure required for operation. In other words, prompt setting is initiated at high speed but the final incremental movement to achieve setting is accomplished under relatively high pressure. The check valve 84 supplies fluid from the piston face 76 to the face 78 during the setting or extension operation if for some reason the piston 72 has reached its full travel before the setting pistons have reached their full travel.
Now, when it is time to retrieve the formation tester 10 from the borehole, a suitable signal is applied to the solenoid valves 62 and 64. Recall that the valve 64 is the retraction valve. It is moved by suitable solenoid signal to the switched position. This delivers pump pressure through the retraction line 98. This drives all four of the hydraulic mechanisms in the opposite direction. That is, the probe 30 is retracted by the two means that operate the probe while the two backup shoes 38 and 48 are also retracted. At this moment, the setting line 82 is then used as a return line for fluid to sump. Before this begins, the piston 72 is at the downward position. It is forced upwardly. The line 82 thus delivers fluid into the fluid multiplier. Any surplus fluid above the piston is also expelled through the check valve 86 which then delivers fluid through the valve 62 and to sump. This enables the piston 72 to move to the upper end of its stroke. The last part of movement is accomplished by the fluid bypassing the piston 72 when the enlarged upper end of the cylinder is entered.
The foregoing describes the hydraulic circuit and sets forth the mode of operation of the fluid multiplier 70. An important feature of this apparatus is that high speed movement is obtained at the beginning stroke of the various hydraulic rams shown in FIG. 2. When they encounter resistance, the speed may slow down but the pressure then builds up to assure proper and adequate setting. This is desirable also because it helps properly drive the probe through the mud cake in the well borehole and also assures proper penetration of the snorkel to obtain test data from the formation of interest.
The present invention thus provides marked improvement in setting time. This improvement translates into reduced time in which the apparatus is downhole and reduces rig time. The accelerated operation of the equipment reduces the time in which the formation tester is downhole. This is achieved with more rapid setting of the probe to enable subsequent penetration by the snorkel.
While the foregoing is directed to the preferred embodiment, the scope thereof is determined by the claims which follow.
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In a formation tester constructed with an extendable probe driven by hydraulic means, the means being connected to a hydraulic circuit, an improved apparatus is set forth which includes a hydraulic fluid multiplier means. This multiplier means is connected between the pump and the means extending the probe and backup shoes. The multiplier means incorporates a step piston and a large cylinder having a step conforming with the piston. Suitable seals are placed on the piston. The piston drives initially to deliver a high volume low pressure flow to extend rapidly the probe, and completes its operation with a low volume high pressure flow to assure proper setting. This enables more rapid operation and more rapid completion of formation testing.
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RELATED APPLICATIONS
This application claims priority to U.S. Provisional Patent Application No. 60/328,035, filed Oct. 9, 2001, incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not applicable.
FIELD OF THE INVENTION
The present invention generally relates to auto-thermal heating of an endothermic reaction by combusting a reaction by-product. More particularly, the present invention relates to an apparatus and method for producing synthesis gas from methane by an endothermic steam reforming reaction wherein a hydrogen permeable membrane separates excess hydrogen produced by the reaction and the excess hydrogen is combusted to provide heat to the endothermic steam reforming reaction.
BACKGROUND OF THE INVENTION
Large quantities of methane, the main component of natural gas, are available in many areas of the world. However, a significant portion of that natural gas is situated in areas that are geographically remote from population and industrial centers (“stranded gas”). The costs of compression, transportation, and storage often makes the stranded gas' use economically unattractive. Consequently, the stranded natural gas is often flared. Flaring not only wastes the energy content and any possible economic value the natural gas may have but also creates environmental concerns.
To improve the economics of natural gas transportation and utilization, much research has focused on using the methane component of natural gas as a starting material for the production of higher hydrocarbons and hydrocarbon liquids. The conversion of methane to hydrocarbons is typically carried out in two steps. In the first step, methane is reacted to produce carbon monoxide and hydrogen (i.e., synthesis gas or “syngas”). In a second step, the syngas is converted to higher hydrocarbon products by processes such as Fischer-Tropsch synthesis. For example, fuels with boiling points in the middle distillate range, such as kerosene and diesel fuel, and hydrocarbon waxes may be produced from the syngas. In addition, syngas may be used for the manufacture of ammonia, hydrogen, methanol, and other chemicals. Less traditional uses of syngas continue to be developed and have increased in importance in recent years, such as in the production of acetic acid and acetic anhydride manufacture. Among the promising new developments in syngas chemistry are routes to ethylene.
The syngas routes may be attractive in themselves, regardless of raw materials used; they may also provide the option to use alternative and ultimately cheaper raw materials such as coal and, in certain circumstances, natural gas. One of the attractions of syngas is that it can be manufactured from almost any raw material containing carbon; hence, the availability of feedstock is ensured.
The cost of syngas can be highly variable, depending on the effluent hydrogen/carbon monoxide ratio desired, the raw materials available, the production process, the scale of operation and extent of integration with other processes, and other factors. As described below, the current methods for producing syngas all have negative aspects, which result in inefficiencies, and in turn, a higher cost of producing syngas.
There are currently three primary reactions for converting methane to syngas. Those methods include: steam reforming (the most widespread), dry reforming (also called CO 2 reforming), and partial oxidation. Steam reforming, dry reforming, and partial oxidation proceed according to the following reactions respectively:
CH 4 +H 2 O+heat→CO+3H 2 (1)
CH 4 +CO 2 +heat→2CO+2H 2 (2)
CH 4 +½O 2 →CO+2H 2 +heat (3)
For a general discussion of steam reforming, dry (or CO 2 ) reforming, and partial oxidation, please refer to H AROLD G UNARDSON , Industrial Gases in Petrochemical Processing 41-80 (1998), the contents of which are incorporated herein by reference for all purposes.
As noted in reaction 1, steam reforming is endothermic (requires heat); therefore, heat must be supplied to drive the reaction. One way to provide the necessary heat is to burn a portion of the available natural gas in process heaters. However, because some of the available natural gas is burned to heat the reactor, less natural gas is available to be converted to synthesis gas and the overall yield is lower than if all of the natural gas were converted to syngas. Other methods of supplying heat to the steam reforming reaction at remote well sites are often cost prohibitive. In addition, the steam reforming reaction is relatively slow, thereby requiring relatively long reactor residence times and correspondingly large reactors. These typically large steam reforming plants are usually not practical to set up at remote natural gas well sites.
Partial oxidation of hydrocarbons can also be used to produce syngas. Partial oxidation of hydrocarbons to produce syngas typically takes place in the presence of a catalyst. In catalytic partial oxidation (“CPOX”), natural gas is mixed with air, oxygen-enriched air, or oxygen, and introduced to a catalyst at elevated temperature and pressure. The methane reacts exothermically with oxygen to form syngas. A specific example of a CPOX process is set forth in U.S. Pat. No. 5,510,056 to Jacobs, et al., incorporated herein by reference for all purposes.
Recently, CPOX of methane has attracted much attention due to its inherent advantages, such as the fact that due to the significant heat that is released during the process, there is no requirement for the continuous input of heat in order to maintain the reaction. This is in contrast to steam reforming processes, which generally use external gas firing that decreases total liquid product yields (discussed above). CPOX also has space saving advantages. CPOX is a very fast reaction; therefore, reactor residence times are much less than those needed for steam reforming and thus, smaller reactors are acceptable. In addition, CPOX produces syngas with the optimal 2:1 H 2 :CO molar ratio for Fischer-Tropsch reactions, and has a simplified catalytic reaction plant section.
CPOX is not without its drawbacks. In CPOX, oxygen and methane must be mixed in the presence of a catalyst. Mixing of these components in certain temperature and pressure regimes can potentially lead to explosions, fires, and equipment failures. Because of this, CPOX has so far been substantially limited to low pressures due to the safety concerns. In addition, although it is possible to conduct a partial oxidation reaction in the presence of air or oxygen-enriched air it is often preferable to conduct the reaction in the presence of substantially pure oxygen because if other than substantially pure oxygen is used, diluants in the air (e.g., N 2 ) will require the use of a much larger reactor, thus increasing the cost to build and operate and reducing or eliminating the size advantage of CPOX over steam reforming. Unfortunately, separation, compression, and handling of the substantially pure oxygen can be very expensive.
Another process for producing syngas is autothermal reforming (“ATR”). ATR is basically a combination of partial oxidation and steam reforming carried out in a single reactor. The heat released by the exothermic partial oxidation reaction is used to drive an endothermic steam reforming reaction in another part of the reactor.
One of the features of ATR is that it requires no external fuel. ATR also reduces, but does not eliminate, some of the safety issues involved with CPOX because a burner is used. The burner allows for the safe mixing and combustion of methane with oxygen. However, ATR also has negative aspects. For example, large amounts of CO 2 are generated in the partial oxidation portion of an ATR reactor. This reduces the overall conversion of methane to CO. Additionally, removal of that CO 2 increases the expense of the overall processing scheme. A detailed discussion of ATR is included on pages 61-66 of the G UNARDSON referenced cited above.
With regard to the membrane art, research done by Prabhu, Radhakrishnan, and Oyama (P RABHU, ET AL., Supported Nickel Catalysts for Carbon Dioxide Reforming of Methane in Plug Flow and Membrane Reactors , A PPLIED C ATALYSIS A: G ENERAL 241-52 (1999) (“P RABHU, ET AL .”)), incorporated herein by reference in its entirety for all purposes, discloses the use of a hydrogen permeable membrane to separate hydrogen from the reaction product of a dry reforming reaction to shift equilibrium conditions and increase the methane conversion in the reactor. As is shown in FIG. 9 of P RABHU, ET AL ., the Vycor® membrane used was effective up to a temperature of at least 1023 K. It should be noted that the P RABHU, ET AL . reference does not teach the combustion of the permeated hydrogen and instead uses a Hoskins tubular furnace to drive the endothermic dry reforming reaction. Likewise, U.S. Pat. No. 5,637,259 to Galuszka et al., incorporated herein by reference for all purposes, discloses the use of a hydrogen permeable membrane to separate hydrogen from the reaction product of a dry reforming reaction and a catalytic partial oxidation reaction to shift equilibrium conditions and increase the methane conversion and the H 2 and CO selectivities in the reactor. Like P RABHU ET AL ., Galuszka et al. does not teach the combustion of the separated hydrogen to drive the reaction or the use of a membrane in conjunction with a stream reforming reaction.
Because syngas is used in both methanol, Fischer-Tropsch, and other syntheses, the demand for syngas remains high. This has fueled syngas research, which has resulted in processes such as steam reforming, CPOX, and ATR. However, while these competing processes have benefits, they also have flaws or limitations, which ultimately limit their utility. Therefore, there exists a need for new processes that exhibit at least some of the positive features of these competing processes, while reducing or eliminating the negative features or limitations.
SUMMARY OF THE INVENTION
The present invention embodies some of the positive features of steam reforming, CPOX, and ATR, while reducing some of the negative aspects. The result is a hybrid process that approaches the relatively high yield of partial oxidation while reducing the safety and pressure concerns. Like ATR, the new process uses internal combustion to heat the process, but greatly reduces the CO 2 generation and safety concerns of ATR.
In a preferred embodiment of the present invention, an apparatus for producing syngas includes a steam reforming catalyst bed, a hydrogen permeable membrane, and a substantially enclosed combustion zone, where the hydrogen permeable membrane separates the catalyst bed from the combustion zone.
In another preferred embodiment of the present invention, a process for producing syngas includes contacting a feed stream of methane and water with a catalyst in a reaction zone maintained at steam reforming conditions effective to produce an effluent stream of hydrogen and carbon monoxide at a ratio of about 3:1 and removing excess hydrogen via a hydrogen permeable membrane to produce an effluent stream of hydrogen and carbon monoxide at a ratio of about 2:1. The removed excess hydrogen is combusted in a combustion zone to provide heat to drive the endothermic steam reforming reaction in the reaction zone.
Another preferred embodiment comprises a reactor system for carrying out an endothermic reaction to form reaction products comprising a first substantially enclosed reactor zone and a second substantially enclosed reactor zone in physical and thermal contact with the first reactor zone. The physical interface between the first and second reactor zones defines a contact surface, where at least a portion of the contact surface (and possibly the entire contact surface) comprises a selectively permeable membrane for allowing a first gas, such as hydrogen, to pass from the second reactor zone to the first reactor zone. The first reactor zone is adapted for combusting the first gas and the second reactor zone is preferably adapted for carrying out an endothermic reaction, such as steam or dry reforming of a hydrocarbon, which produces a gaseous reaction product, such as syngas. The combustion of the first gas supplies heat to at least partially (and possibly completely) drive the endothermic reaction.
The preferred reactor system can be designed such that the second reactor zone is substantially contained within the first reactor zone, the second reactor zone is adjacent to, but not substantially contained within, the first reactor zone, or the first reactor zone is substantially contained within the second reactor zone.
The second reactor zone preferably contains a catalyst to catalyze the endothermic reaction, and the first reactor zone preferably contains a means for initiating the combustion of the first gas, such as described herein.
Another preferred embodiment further comprises a third substantially enclosed zone in physical contact with the second reactor zone, the physical interface between the second reactor zone and the third zone defines another contact surface, where at least a portion of (and possibly all of) the contact surface comprises a selectively permeable membrane for allowing the first gas to pass from the second reactor zone to the third zone. Also preferably included is a recycle stream for recycling the first gas from the third zone into the first zone.
Another preferred embodiment includes a method for conducting an endothermic reaction, including providing a first reactor defining a reaction zone and having a feed stream intake opening and a product stream outlet opening; providing a second reactor defining a combustion zone and having an oxygen intake opening and an exhaust opening; providing a selectively permeable membrane between and separating the reaction zone and the combustion zone; conducting an endothermic reaction, preferably the steam reforming of the methane to produce syngas, which produces excess combustible gas, preferably hydrogen, in the reaction zone, where at least some of the excess combustible gas permeates through the selectively permeable membrane into the combustion zone; and combusting at least some of the permeated excess combustible gas in the combustion zone, where heat generated by the combustion of the combustible gas drives the endothermic reaction in the reaction zone.
Another preferred embodiment includes a method for producing syngas with a hydrogen to carbon monoxide ratio of about 2:1 comprising the steps of providing a combustion reactor having an oxygen intake opening and an exhaust opening; providing a steam reforming reactor having walls and a feed stream intake opening and a product stream outlet opening, wherein the steam reforming reactor is substantially inside of the combustion reactor and the walls of the steam reforming reactor comprise a substantially hydrogen only permeable membrane; providing a catalyst system inside of the steam reforming reactor to catalyze the steam reforming of methane to produce syngas with a hydrogen to carbon monoxide ratio of about 3:1, wherein about ⅓ of the hydrogen generated permeates through the substantially hydrogen only permeable membrane into the combustion reactor; and combusting the permeated hydrogen in the combustion reactor to provide heat to drive the endothermic steam reforming reaction in the steam reforming reactor.
Another preferred embodiment includes a process for producing a syngas stream with a hydrogen to carbon monoxide molar ratio of a predetermined amount, such as 2:1, the process comprising a means for steam reforming a hydrocarbon containing feed stream, such as methane or natural gas, to produce a syngas stream with a hydrogen to carbon monoxide ratio of greater than the predetermined amount, such as a catalyst system for steam reforming; a means for in-situ separating excess hydrogen from the syngas stream; and a means for combusting at least a portion of the excess hydrogen to produce heat to drive the means for steam reforming. In addition, preferably, there is included a means for supplying oxygen to the means for combusting and a means for exhausting the combusted hydrogen from the means for combusting.
The catalyst system preferably comprises a catalyst support and a catalyst, such as described herein.
Another preferred embodiment includes a reactor system for carrying out steam reforming of methane to produce synthesis gas, the reactor system comprising a first reactor comprising a steam reforming zone containing a catalyst bed, a reactant gas inlet and a product gas outlet; a second reactor at least partially surrounding the first reactor and comprising an H 2 combustion zone, an oxygen inlet and an exhaust gas outlet; and a thermally conductive substantially H 2 only permeable membrane disposed between the reforming zone and the combustion zone. The catalyst bed contains a catalyst capable of catalyzing the steam reforming of methane to produce synthesis gas under reaction promoting conditions.
Another preferred embodiment includes a method of reducing the H 2 :CO molar ratio of a synthesis gas stream comprising providing a reactor system including: a first reactor having a steam reforming zone containing a catalyst bed, a reactant gas inlet and a synthesis gas outlet, a second reactor at least partially surrounding the first reactor and comprising a combustion zone, an air inlet and an exhaust gas outlet, and a thermally conductive substantially hydrogen only permeable membrane disposed between the reforming zone and said combustion zone; contacting a mixture of methane and steam in the steam reforming zone with a catalyst capable of catalyzing the reaction CH 4 +H 2 OH 2 +CO under reaction promoting conditions to provide a stream of product gas comprising hydrogen and carbon monoxide in a molar ratio of about 3:1; maintaining a higher gas pressure in the first reactor than in the second reactor, such that a portion of the hydrogen product gas passes through the membrane into the combustion zone; mixing a source of oxygen with the portion of hydrogen product gas in the combustion zone; igniting the hydrogen and oxygen in the combustion zone to produce heat; conducting at least a portion of the heat into the steam reforming zone such that the steam reforming reaction is at least partially sustained by the heat; and harvesting a modified synthesis gas stream comprising a molar ratio less than about 3:1 of H 2 :CO. Preferably, the method also includes harvesting a modified synthesis gas stream having a molar ratio of H 2 :CO of about 2:1.
Another preferred embodiment includes a reactor system for carrying out an endothermic reaction to form reaction products, the reactor system comprising a first substantially enclosed reactor zone; a second substantially enclosed reactor zone in thermal contact with the first reactor zone; and a selectively permeable membrane system separating the first reactor zone from the second reactor zone. The second reactor zone is adapted for carrying out the endothermic reaction which produces a first combustible gas. The selectively permeable membrane system is adapted to help extract the first combustible gas from the first reactor zone into the second reactor zone. The first reactor zone is adapted for combusting the first combustible gas, and the combustion of the first combustible gas supplies heat to at least partially drive the endothermic reaction.
Another preferred embodiment includes a reactor system for carrying out an endothermic reaction, the reactor system comprising a reaction zone substantially enclosed by a selectively permeable membrane; a combustion zone surrounding the selectively permeable membrane, wherein the combustion zone is substantially enclosed by a reactor shell. The reactor shell has an oxygen inlet and an exhaust outlet. The reaction zone has a reactant inlet and a product outlet. The reactor system comprises a plurality of sections including at least an anterior section and a posterior section (and preferably, but not necessarily, an intermediate section), and the plurality of section are detachable from each other when the reactor system is not in use.
The present invention generally avoids some of the negative features of steam or dry reforming, CPOX, and ATR, while capturing some of the benefits of these processes. The result is a more efficient, lower cost syngas process.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more detailed understanding of the present invention, reference is now made to the accompanying figures. In the accompanying of figures substantially similar components have been identically numbered for ease of reference.
FIG. 1 is a cross-sectional schematic drawing of a first embodiment of the present invention.
FIG. 2 is a cross-sectional schematic drawing of a second embodiment of the present invention.
FIG. 3 is a cross-sectional schematic drawing of a third embodiment of the present invention.
FIG. 4 is a cross-sectional schematic drawing of a fourth embodiment of the present invention.
FIG. 5 is a cross-sectional schematic drawing of a fifth embodiment of the present invention.
FIG. 6 is a cross-sectional schematic drawing of a sixth embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1 , one embodiment of the present system, reformer reactor 160 includes a steam reforming reaction chamber 120 , a reactor inlet 60 and a syngas outlet 70 . Reaction chamber 120 is substantially encased by a hydrogen permeable membrane 130 and a combustion zone 140 . Combustion zone 140 is substantially encased by a refractory lining 100 and metal shell 110 having an air inlet 80 and an exhaust opening 90 . The reaction chamber 120 includes a catalyst system as herein defined.
In operation, methane stream 10 and water stream 20 are blended to comprise a methane-water feed stream 150 . Methane-water feed stream 150 enters steam reforming reaction chamber 120 , where a steam reforming reaction takes place accordingly. Excess hydrogen is separated internally by use of substantially hydrogen only permeable membrane 130 in the reformer reactor. This excess hydrogen feeds into combustion zone 140 . Air 40 is drawn into the combustion chamber 140 through air inlet 80 where it is combusted with the excess hydrogen to supply heat to and drive the endothermic steam reforming reaction taking place in reaction chamber 120 . The exhaust 50 , composed of the product of the hydrogen combustion along with any other gases in the combustion chamber, are then exhausted through the exhaust opening 90 . The combustion can be initiated by catalyst in the combustion zone, by establishing a flame or spark, by auto-ignition, or by any other acceptable method. The heat generated from the hydrogen combustion maintains the high temperatures necessary for steam reforming inside reaction chamber 120 , resulting in a product stream 30 containing primarily syngas which exits chamber 120 via syngas outlet 70 .
Referring now to FIG. 2 , a second embodiment of the present system, reformer reactor 160 includes a steam reforming reaction chamber 120 , a reactor inlet 60 and a syngas outlet 70 . Reaction chamber 120 is encased by a hydrogen permeable membrane 130 , refractory lining 170 , and metal shell 180 . Combustion zone 140 is encased by a refractory lining 100 and metal shell 110 having an air inlet 80 and an exhaust opening 90 . The reaction chamber 120 includes a catalyst system as herein defined.
In operation, methane stream 10 and water stream 20 are blended to comprise a methane-water feed stream 150 . Methane-water feed stream 150 enters steam reforming reaction chamber 120 , where a steam reforming reaction takes place accordingly. Excess hydrogen is separated internally by use of substantially hydrogen only permeable membrane 130 in the reformer reactor. This excess hydrogen feeds into combustion zone 140 . Air 40 is drawn into the combustion chamber 140 through air inlet 80 where it is combusted with the excess hydrogen to supply heat and drive the endothermic steam reforming reaction taking place in reaction chamber 120 . The product of the hydrogen combustion, along with any other gases in the combustion chamber are then exhausted through the exhaust opening 90 . The combustion can be initiated by catalyst in the combustion zone, by establishing a flame or spark, by auto-ignition, or by any other acceptable method. The heat generated from the hydrogen combustion maintains the high temperatures necessary for steam reforming inside reaction chamber 120 , resulting in a product stream 30 containing primarily syngas which exits chamber 120 via outlet 70 .
Referring now to FIG. 3 , there is shown an adjustable stackable embodiment of the present invention. In this embodiment, four individual components 200 , 210 , 220 , and 230 of the reactor system 160 can be assembled to form an assembled reactor system, (such as, for example, the reactor system of FIG. 1 ). The component interfaces 190 are designed, as is well known in the art, to connect and interface such that overall reactor performance is not substantially hindered. It is also envisioned that the embodiment of FIG. 3 could be expanded or contracted in size by varying the number of intermediate sections (e.g., 210 and 220 ) from one to several. The optimal length, as also with FIG. 1 and FIG. 2 , is to be determined by one of ordinary skill in the art and may vary depending on the ultimate product stream application and the physical limitations of the manufacturing materials.
When in assembled operation, methane stream 10 and water stream 20 are blended to comprise a methane-water feed stream 150 . Methane-water feed stream 150 enters catalyst filled steam reforming reaction chamber 120 via reactor inlet 60 , where a steam reforming reaction takes place accordingly. Excess hydrogen is separated internally by use of substantially hydrogen only permeable membrane 130 in the reformer reactor. This excess hydrogen feeds into combustion zone 140 . Air 40 is drawn into the combustion chamber 140 through air inlet 80 where it is combusted with the excess hydrogen to supply heat to and drive the endothermic steam reforming reaction taking place in reaction chamber 120 . The product of the hydrogen combustion, along with any other gases in the combustion chamber are then exhausted through the exhaust opening 90 . The combustion can be initiated by catalyst in the combustion zone, by establishing a flame or spark, by auto-ignition or by any other acceptable method. The heat generated from the hydrogen combustion maintains the high temperatures necessary for steam reforming inside reaction chamber 120 , resulting in a product stream 30 containing primarily syngas which exits chamber 120 via outlet 70 .
It is envisioned that the stackable system embodied in FIG. 3 should not be limited to a reactor in which the reaction zone 120 is completely enclosed in the combustion zone 140 . It is envisioned that other embodiments of the present invention, such as those of FIGS. 2 , 3 , 4 , 5 , and 6 , can also be configured as an assembly of multiple components. This stackable assembly will ease the transportability and assembly of the reactor system, thereby increasing its flexibility and mobility. Hence, this stackable embodiment can be a valuable tool for processing natural gas at remote locations.
Referring now to FIG. 4 , there is shown an embodiment of the present invention in which the reaction chamber 120 is not completely enclosed within the combustion chamber 140 . In FIG. 4 , reformer reactor 160 includes a steam reforming reaction chamber 120 , a reactor inlet 60 and a syngas outlet 70 . Reaction chamber 120 is partially encased by a hydrogen permeable membrane 130 and a combustion zone 140 . The remainder of reaction chamber 120 is encased by a reactor liner 175 comprised of refractory lining 170 and metal shell 180 . Combustion zone 140 is encased by a refractory lining 100 and a metal shell 110 having an air inlet 80 and an exhaust opening 90 . The reaction chamber 120 includes a catalyst system as herein defined.
In operation, methane stream 10 and water stream 20 are blended to comprise a methane-water feed stream 150 . Methane-water feed stream 150 enters steam reforming reaction chamber 120 , where a steam reforming reaction takes place accordingly. Excess hydrogen is separated internally by use of substantially hydrogen only permeable membrane 130 in the reformer reactor. This excess hydrogen feeds into combustion zone 140 . Air 40 is drawn into the combustion chamber 140 through air inlet 80 where it is combusted with the excess hydrogen to supply heat to and drive the endothermic steam reforming reaction taking place in reaction chamber 120 . The exhaust 50 , composed of the product of the hydrogen combustion along with any other gases in the combustion chamber, is then exhausted through the exhaust opening 90 . The combustion can be initiated by catalyst in the combustion zone 140 , by establishing a flame or spark, by auto-ignition, or by any other acceptable method. The heat generated from the hydrogen combustion maintains the high temperatures necessary for steam reforming inside reaction chamber 120 , resulting in a product stream 30 containing primarily syngas which exits chamber 120 via syngas outlet 70 .
Referring now to FIG. 5 , there is shown an embodiment of the present invention which includes a combustion zone 140 encasing a portion of the reaction zone 120 and a recycle zone 300 encasing another portion of the reaction zone 120 . Excess hydrogen permeates through substantially hydrogen only permeable membrane 130 into combustion zone 140 and recycle zone 300 . At least a portion of the hydrogen permeating into the recycle zone 300 is recycled into combustion zone 140 where it is combusted with the hydrogen permeating directly into the combustion zone 140 from the reaction zone 120 .
In operation, methane stream 10 and water stream 20 are blended to comprise a methane-water feed stream 150 . Methane-water feed stream 150 enters steam reforming reaction chamber 120 , where a steam reforming reaction takes place accordingly. Excess hydrogen is separated internally by use of substantially hydrogen only permeable membrane 130 in the reformer reactor. This excess hydrogen feeds into combustion zone 140 and recycle zone 300 . At least a portion of the hydrogen permeating into the recycle zone 300 is recycled back into the combustion zone 140 via recycle stream 250 . Air 40 is drawn into the combustion chamber 140 through air inlet 80 where it is combusted with the hydrogen that permeates directly into the combustion zone 140 and the recycle zone 250 to supply heat to and drive the endothermic steam reforming reaction taking place in reaction chamber 120 . The exhaust 50 , composed of the product of the hydrogen combustion along with any other gases in the combustion chamber, is then exhausted through the exhaust opening 90 . The combustion can be initiated by catalyst in the combustion zone, by establishing a flame or spark, by auto-ignition, or by any other acceptable method. The heat generated from the hydrogen combustion maintains the high temperatures necessary for steam reforming inside reaction chamber 120 , resulting in a product stream 30 containing primarily syngas which exits chamber 120 via syngas outlet 70 . The hydrogen recycle stream 250 allows for localization of the hydrogen combustion in instances in which it is not desirable for the combustion to take place along the entire length of the reaction zone 120 .
Referring now to FIG. 6 , there is shown an embodiment in which the combustion chamber 14 is encased by hydrogen permeable membrane 130 and reaction chamber 120 .
In operation, methane stream 10 and water stream 20 are blended to comprise a methane-water feed stream 150 . Methane-water feed stream 150 enters steam reforming reaction chamber 120 , where a steam reforming reaction takes place accordingly. Excess hydrogen is separated internally by use of substantially hydrogen only permeable membrane 130 in the reformer reactor. This excess hydrogen feeds into combustion zone 140 . Air 40 is drawn into the combustion chamber 140 through air inlet 80 where it is combusted with the excess hydrogen to supply heat to and drive the endothermic steam reforming reaction taking place in reaction chamber 120 . The exhaust 50 , composed of the product of the hydrogen combustion along with any other gases in the combustion chamber, are then exhausted through the exhaust opening 90 . The combustion can be initiated by catalyst in the combustion zone, by establishing a flame or spark, by auto-ignition, or by any other acceptable method. The heat generated from the hydrogen combustion maintains the high temperatures necessary for steam reforming inside reaction chamber 120 , resulting in a product stream 30 containing primarily syngas which exits chamber 120 via syngas outlet 70 .
As can be seen, adding together the combustion and steam reforming reactions in the syngas generation embodiment of the present invention gives the overall reaction for syngas generation:
H 2 + 1 2 O 2 -> H 2 O + heat ( 4 ) CH 4 + H 2 O + heat -> CO + 3 H 2 ( 1 ) CH 4 + 1 2 O 2 -> CO + 2 H 2 + heat ( 3 )
This overall reaction is the same as the primary reaction in a CPOX process (reaction 3 ). However, unlike CPOX, in the process of the present invention combustion is separated from the main reaction mixture and the combustion controlled by the amount of air made available to the combustion zone. This reduces many of the safety concerns present in a partial oxidation process.
The hydrogen permeable material used in the present invention should be resistant to high temperatures, preferably functioning at temperatures of at least about 800° C.-1000° C. A suitable material should also conduct heat well, resist oxidation, and allow for selective hydrogen mobility through the wall. A suitable material has sufficient heat transfer capabilities if for any desired configuration of the present invention, a sufficient amount of heat is transferred to the reaction zone to achieve the heat transfer objectives of that particular embodiment. For example, in the embodiment of FIG. 1 , the heat transfer rate is sufficient if enough heat is transferred to drive the steam reforming reaction in the reaction zone without the need for an outside heat source. An example of such a material is a ceramic ion transport membrane, or more specifically, a mixed conduction membrane. A suitable material for the hydrogen permeable membrane is the modified Vycor® (Corning, Inc.) glass material disclosed in P RABHU AND O YAMA , Development of a Hydrogen Selective Ceramic Membrane and Its Application for the Conversion of Greenhouse Gases , 1999 Chemical Letters 213-14 (“P RABHU AND O YAMA ”), the contents of which are incorporated herein by reference in their entirety for all purposes.
It is contemplated that any configuration in which the reaction zone is separated from the combustion zone by a selectively permeable membrane which allows substantially only a predetermined gas (or gases) to permeate will fall within the scope of the present invention. By way of example only, a coiled substantially hydrogen only permeable membrane tube residing within the combustion zone and a reaction zone sandwiched between two combustion zones wherein two substantially hydrogen only permeable membranes are employed to separate the reaction zone from the two combustion zones are contemplated to be within the scope of the present invention.
It is also contemplated that there may be configurations of the present invention in which membrane systems or multiple membranes may be used to achieve the desired gas separation. For example, a two-stage separation may be needed to achieve the desired final separation, in which case the membrane system would consist of a first membrane to achieve the first separation and a second membrane to further separate the product of the first separation.
It is further contemplated that the present invention is not limited to any particular directional relationship between the combustion zone flow and the reaction zone flow. For example, the arrows of FIG. 2 indicate that the flow in the combustion chamber is countercurrent to the flow in the reaction chamber. On the other hand, in FIG. 6 , the flow within the combustion chamber and within the reaction zone are co-current and parallel. The present invention is not limited to any particular flow relationship. It can include countercurrent, unidirectional, perpendicular, parallel, skewed, or curved flows as well as any other acceptable flow relationship so long as the desired heat transfer is maintained.
The present invention allows for combustion internally in the reactor system without allowing nitrogen to dilute the product gas. The pressure differential between the inside of the catalyst tube where the reforming reaction takes place and the outside of the tube where combustion takes place provides the driving force for the hydrogen permeation through the membrane. Low combustion air pressure in the combustion chamber favors the transport of hydrogen through the membrane and the rate of hydrogen permeation can be controlled by controlling the pressure differential across the membrane. It should be noted, however, that the strength of the membrane material may create an upper limit to the pressure differential which may be achieved. Additionally, the rate of hydrogen permeation may be controlled by controlling the thickness of the membrane and the size of the membrane.
The reaction chamber does not need to be completely enclosed by the substantially hydrogen only permeable membrane. The membrane may be only a portion of the member that encloses the reaction zone so long as the substantially hydrogen only permeable membrane is between the reaction zone and the combustion zone and the reaction zone is separate from the combustion zone. Thus, in the syngas embodiments it is contemplated to control the rate of hydrogen permeation to tailor the syngas composition to the specific downstream process requirements or to tailor the rate of combustion. By analogy, in non-syngas embodiments, it is contemplated to control the rate of flammable gas permeation to tailor the product composition or to tailor the rate of combustion.
It is also possible to control the rate of flammable combustion in the combustion zone to control the amount of heat transferred to the reaction zone. The rate of combustion can be controlled by controlling the amount of air (more particularly, oxygen in air) available for combustion of the permeated combustible gas. A temperature sensor can be placed in the reaction zone, and the air flow through the combustion zone adjusted until the desired reaction zone temperature is achieved. The desired temperature may vary depending upon the circumstances.
The following definitions shall apply for the purposes of this specification.
“Excess hydrogen” is defined as any hydrogen generated by the reaction in the reaction zone which is not desired to be in the product stream. Likewise, in an embodiment other than the steam reforming embodiment described, “excess combustible gas” is any gas produced in the reaction chamber which is not desired to be in the product stream and which can be ignited in the presence of oxygen to produce heat. By way of example only, in the steam reforming embodiment in which the reaction produces three hydrogens for each carbon monoxide and the desired hydrogen to carbon monoxide ration in the product stream is two hydrogens for each carbon monoxide, the one extra hydrogen produced is an excess hydrogen.
The term “catalyst system” as used herein means any acceptable system for catalyzing the desired reaction in the reaction zone. By way of example only, the catalyst system of a syngas steam reforming reaction usually includes a support and a catalyst. The support may be, for example, particulates, pills, beads, granules, pellets, rings, monoliths, ceramic honeycomb structures, wire gauze, or any other suitable supports as are known in the art. Likewise, the catalyst may include, for example, a conventional steam reforming catalyst such as nickel. The above examples of supports and catalysts are only examples. There are a plethora of catalysts systems known in the art which would be acceptable and are contemplated to fall within the scope of the steam reforming embodiment of the present invention. Indeed in other embodiments of the present invention not involving syngas reforming, if a catalyst system is required at all, it will be within the skill of one of ordinary skill in the art to determine the proper catalyst system by modifying an existing process in accordance with the present disclosure.
The term “substantially hydrogen only permeable membrane” means a membrane which does not allow a significant amount of any substance other than hydrogen to permeate through the membrane.
The term “drive the reaction” means to provide heat to an endothermic reaction to aid in sustentation of the reaction. A first reaction is “completely driven” by a second reaction when enough heat is provided by the second reaction to sustain the first reaction without addition of heat from another source.
The term “membrane system” means a plurality of complimentary membranes that work together to achieve a desired separation. For example, a two-stage separation may be needed to achieve the desired final separation, in which case the membrane system would consist of a first membrane to achieve the first separation and a second membrane to further separate the product of the first separation.
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Preferred embodiments of the present invention generate a synthesis gas with a molar ratio of hydrogen to carbon monoxide of approximately 2:1 required for Fischer-Tropsch synthesis. Additional hydrogen produced in the steam reforming of methane beyond the requirements for the Fischer-Tropsch reaction is separated from the product gases of the reformer by the use of a hydrogen permeable membrane. Air is passed over the outside of the tube. As the hydrogen contacts the air, it is combusted with oxygen in the air to form water and release the heat necessary to drive the steam reforming reaction.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a card connector, and particularly to a card connector comprising an ejecting mechanism.
2. Description of Prior Arts
Memory cards are known in the art and contain intelligence in the form of a memory circuit or other electronic program. Some form of card reader reads the information or memory stored on the card. Memory cards are used in many applications in today's electronic society, including video cameras, smartphones, music players, ATMs, cable television decoders, toys, games, PC adapters and other electronic applications. A typical memory card includes a contact or terminal array for connection through an electrical connector to a card reader system and then to external equipment. The connector readily accommodates insertion and removal of the card to provide quick access to the information and program on the card. The card connector includes terminals for yieldably engaging the contact or terminal array of the card. Additionally, the connector always has an ejecting mechanism for ejecting the insertion card out.
In one prior art, a card connector has a first connector and a second connector stacked with the first connector. Each connector has an ejecting member mounted on a lateral side thereof, and each ejecting mechanism comprises a pushing bar operated by a user, and an ejecting bar engaging with a card directly for pushing the card out.
However, such card connector is mounted in an electronic equipment, the long pushing bar of the ejecting mechanisms occupy a big space of the internal space of the electronic equipment. Moreover, the mechanism is disposed on the lateral side of the card connector, and there is no additional member to cover thereon completely. Therefore, an interference will be encountered to the ejecting mechanism by other external equipments.
In another prior art, a card connector has an L-shape receiving space. In the receiving space, an ejecting mechanism is fitted and covered partially therein. However, a part of the ejecting mechanism is operated in the receiving space, and make the overall height of the card connector increased.
Therefore, the present invention is directed to solving these various problems by providing a card connector which reduces the overall size of the connector and achieves a stable electrical mechanism.
SUMMARY OF THE INVENTION
An object, therefore, of the invention is to provide a card connector capable of reducing overall size of the connector, saving cost and having a convenient assembly process.
In the exemplary embodiment of the invention, a card connector for receiving a card, includes an insulating housing, a rectangular shell, and an ejecting mechanism. The insulating housing comprises a base section and a base seat at a lateral side of the base section. The shell defines a receiving space having an L-shape card slot and a rectangular space at a back corner of the receiving space along an inserting direction of a card. The ejecting mechanism is mounted on the base seat. The shell covers on the insulating housing with the base section located in the card slot, and the base seat is situated in the rectangular space. A width of the base section and the base seat is approximately equal to that of the shell along a transverse direction perpendicular to an insertion direction of a card.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a card connector of present invention;
FIG. 2 is an exploded and top plan view of the card connector of present invention as shown in FIG. 1 ;
FIG. 3 is a bottom view of the card connector as shown in FIG. 2 ;
FIG. 4 is a top plan view of a first ejecting mechanism, a second ejecting mechanism and an insulating housing of the card connector according with present invention;
FIG. 5 is an exploded and top plan view of a second connector of the card connector according with present invention;
FIG. 6 is a perspective view of the insulating housing of the card connector; and
FIG. 7 is a perspective view of a first card and a second card allowed to be received in the card connector of present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 to FIG. 7 , the present invention provides a card connector 1 which is used for a connection with two cards having mutually different transmission speeds, such as an Express card, and a Smart card. The card connector 1 comprises a first connector 10 defining a first receiving space 14 for receiving a first card A, a second connector 20 stacked with the first connector 10 and defining a second receiving space 220 for receiving a second card B, and an opening (not labeled) for a card inserting/ejecting.
As shown in FIG. 1 and FIG. 2 , the first connector 10 comprises a first metal shell 11 , an insulating housing 30 covered by the first shell 11 , a plurality of first contacts 4 protruding into the first receiving space 14 to engage with the first card A, a first ejecting mechanism 6 and a second ejecting mechanism 5 for ejecting the first card A and the second card B, respectively.
The first shell 11 , approximate a rectangular shape in a top plan view, and an U shape in a front view, comprises a first top wall 12 , and a pair of first lateral walls 13 extending downwardly from the opposite sides of the first top wall 12 . The first receiving space 14 is defined by the first top wall 12 associating with the first lateral walls 13 and is divided into an L-shape card slot 140 to receive the first card A and a rectangular space 141 , as a broken line shown in FIG. 2 . When the first card A is received in the card slot 140 , the rectangular space 141 is rightly at a cut portion F (shown in FIG. 7 ) of the first card A. The first top wall 12 has a pair of first elastic pieces 15 , a pair of second elastic pieces 16 , and a pair of first projecting portions 17 . A sharp angle is defined between each elastic pieces 15 and an insertion direction of the card. The elastic pieces 15 are used for pressing on a metal part C (shown in FIG. 7 ) of the first card A, serving as a grounding portion or fastening portion. The first projecting portions 17 are provided to guide the first card inserted stably. The second elastic pieces 16 extend along the insertion direction of the card.
Referring to FIG. 2 to FIG. 4 , the first insulating housing 30 , structured as an L shape in a top plane view, comprises a base section 31 and a base seat 33 extending laterally from the base section 31 . Getting along a transverse direction perpendicular to the insertion direction of the card, a width D defined by the base section 31 associating with the base seat 33 is approximately equivalent to the width E of the metal shell 11 . The base section 31 has a main portion (not labeled), an arm portion 39 at one end of the main portion, an engaging plate 32 extending from the main portion and perpendicular to the arm portion 39 . The first contact 4 is received in the engaging plate, and each contact 4 comprises an engaging portion 40 , a soldering portion 43 and a connecting portion 41 joining the engaging portion 40 with the soldering portion 43 .
The base seat 33 , designed approximately in a rectangular shape and longer than the base section 31 along the insertion direction of the card, has a first sliding groove 330 and a second sliding groove 331 perpendicular to the first sliding groove 330 . The first sliding groove 330 and the second sliding groove 331 , respectively, have a post 333 , 335 at one end thereof, and a position hole 334 , 336 opposite to corresponding post 333 , 335 . Particularly, the first sliding groove 330 and the second sliding groove 331 have a first sliding channel 332 and a second sliding channel 337 , respectively. The first sliding channel 332 is formed at one edge of the first sliding groove 330 , and the second sliding groove 337 is formed at the bottom of the second sliding groove 331 to communicating with the second card slot 220 . Moreover, in this embodiment of the present invention, the base seat 33 has a triangle plate 33 extending therefrom forwardly and integrally to guide different card inserting.
As shown in FIG. 4 , the first mechanism 6 and the second mechanism 5 are structured almost simple to each other and operated by an inserting card, and comprise, respectively, a first ejecting member 60 , a second ejecting member 50 protruding into corresponding receiving space, a first spring member 62 , a second spring member 52 for moving the ejecting member 60 , 50 towards the card ejecting direction, a first heart groove 63 , a second heart groove 53 and a first latch member 61 , a second latch member 51 sliding in the heart groove 63 , 53 to overcome the spring member 62 , 52 and place the ejecting member 60 , 50 in a desirable position. The first ejecting member 60 and the second ejecting member 50 , respectively, have a first pushing portion 64 extending laterally from one side of the first ejecting member 60 , a second pushing portion 54 (shown in FIG. 6 ) extending downwardly from a bottom of the second ejecting member 50 .
Together with FIG. 2 , FIG. 3 and FIG. 5 , the second connector 20 is placed under the first connector 10 respect to a printed circuit board (not shown) and comprises a second metal shell 21 , a terminal module 23 aligned with the second shell 21 , and a bottom plate 22 associating with the second shell 21 to define the second receiving space 220 .
The second shell 21 is approximately a rectangular shape, and comprises a second top wall 210 , a pair of second side walls 211 extending downwardly from opposite sides of the top wall 210 . The second top wall 210 has a fixing hole 212 in alignment with the terminal module 23 , and a longitudinal groove 213 in accordance with the second slipping groove 337 of the second guiding groove 331 .
The bottom plate 22 is constructed according with the second shell 21 , and comprises a recess 221 to receiving the terminal module 23 . In the terminal module 23 , a plurality of second terminals 24 is retained and protrudes upwardly in the second card slot 220 to engaging with the second card B electrically.
Referring to FIG. 4 , the relationship between the first ejecting mechanism 6 , the second ejecting mechanism 5 and the first groove 330 , the second groove 331 will be described in detail. The first ejecting mechanism 6 is mounted in the first groove 330 with the first pushing portion 64 protruding into the first card slot 140 , one end of the spring member 62 connecting the ejecting member 60 and the other aligned with the post 333 , one end of the latch member 61 slipping in the heart groove 63 and the other placed in the position hole 334 . The second ejecting mechanism 5 is mounted in the second groove 331 in the same way as described of the first ejecting mechanism 6 , except that the second pushing portion 54 protrudes downwardly into the second receiving space 220 by going through the second slipping channel 337 and the longitudinal groove 213 of the second metal shell 21 orderly, as shown in FIG. 2 and FIG. 6 .
According with present invention, the first ejecting mechanism 6 and the second mechanism 5 is mounted in the first sliding groove 330 and the second sliding groove 331 , more particularly, both the first sliding groove 330 and the second sliding groove 331 are formed on the base seat 33 side by side, and the base seat 33 is rightly fitted in the rectangular space 141 . On one hand, it is needless to design another module to couple with the ejecting mechanisms. So a simple, convenient assembly process is achieved, accordingly, to save cost. On the other hand, the base seat 33 allows more ejecting mechanisms to be designed thereon, but do not take additional room as before to save more space. Besides, the first mechanism 6 and the second mechanism 5 are covered by the first shell 14 completely avoiding to being disposed out thereof and interfered by other device.
In this embodiment of present invention, the card connector 1 is structured by vertically stacking two connectors that receive different cards. In another embodiment, a card connector is constructed by three connectors for receiving three cards, and one connector is designed as the first card connector 10 described above with three two ejecting mechanisms mounted on a base seat 33 thereof, and the other two connectors are stacked vertically on opposite sides of said connector. The ejecting mechanisms protrude into corresponding card slot upwardly or downwardly to engaging with cards. Such structure also reduces overall size of the card connector, and save more space. In a third embodiment, a card connector comprises two card connectors arranged in a transverse direction or in a level, and two ejecting mechanisms are placed on a base seat formed between the two connectors, particularly, one of the connector should be designed as the first connector 1 , and a base seat is rightly received in a rectangular space to couple with ejecting mechanisms.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
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A card connector ( 1 ) for receiving a card, includes an insulating housing ( 30 ), a rectangular shell ( 11 ), and an ejecting mechanism ( 5, 6 ). The insulating housing comprises a base section ( 31 ) and a base seat ( 33 ) at a lateral side of the base section. The shell defines a receiving space ( 220 ) having an L-shape card slot ( 140 ) and a rectangular space ( 141 ) at a back corner of the receiving space along an inserting direction of a card. The ejecting mechanism is mounted on the base seat. The shell covers on the insulating housing with the base section located in the card slot, and the base seat is situated in the rectangular space. A width of the base section and the base seat is approximately equal to that of the shell along a transverse direction perpendicular to an insertion direction of a card.
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FIELD OF THE INVENTION
The present invention is directed to a wall article hanging device and methods of use, and in particular, to a hanging device including a separable prong element, its separability easing handling of the article prior to hanging and permitting alternative hanging techniques.
BACKGROUND ART
In the prior art, a number of techniques are employed to hang a wall article such as a picture, painting, mirror, tapestry, etc. One such technique employs a nail or other member that is attached to the wall, whereby the nail acts as the support for the article to be hung. The article to be hung can then be fitted with a wire, and the wire is slipped over the protruding nail to support the article. The article can also use other types of hanging devices such as serrated plates that are attached to the back of a frame, with the nail engaging one of the serrations on the plate for frame support. The article can also be hung by attaching a hanger device having a loop, whereby the nail would engage the loop for article support.
Another class of wall article hanging devices are disclosed in U.S. Pat. Nos. D339,981, 5,328,139, 5,588,629, 5,758,858, and 6,095,478 to Barnes. These patents run counter to the conventional wall article hanging techniques that first attach an element to the wall, and then hang the wall article off that wall element. In the Barnes' patents, a hanging device is first attached to the wall article to be hung, and then the wall article is secured to a wall surface. Using the Barnes' device and method, there is no need for locating a nail or the like at a predetermined location on the wall so as to position the wall article in the proper location. That is, the wall article itself is used for positioning in the proper site on the wall.
The Barnes' devices are also advantageous in that the wall article is secured in such a fashion that the article remains stationary after attachment, and the constant article leveling that goes on when a wire and nail are used is eliminated.
The Barnes' patents use one or more prongs as part of the attaching device and technique. One problem with these devices is that the prongs extend away from the article to be hung, and can pose a problem in terms of shipping and handling the wall article before it is hung. For example, if a Barnes' hanging device is first attached to a wall article, and then the wall article is shipped to a retail or wholesale location for resale, the prongs of the hanging device extend away from the back of the article to be hung. Since the prongs are pointed, they pose a hazard in terms of injuring one who is handling the article. To minimize this hazard, and the prongs can be covered in order to avoid such injury. Having to cover the prongs imposes an added burden when the article is being shipped or stored for sale or installation.
In light of the problem noted above, a need exists to provide an improved wall article hanging device. In response to this need, the present invention solves the problem of prong exposure by providing a device whereby the prongs of the device are separable until ready for use, i.e., separate from the part of the device retaining the prongs in place, for shipment or resale, and then are installed once the article is to be hung. The invention also provides alternative hanging capacities in the event that a conventional picture hanging technique may be preferred by the article hanger, e.g., wire and nail.
SUMMARY OF THE INVENTION
It is a first object of the present invention to provide an improved wall article hanging device.
Another object of the invention is to provide a method of hanging wall articles.
Still another object of the invention is a wall article hanging device offering the person hanging the article a number of options for hanging.
One other object of the invention is a prong-containing wall article hanging device, whereby the part without prongs can be attached to the wall article before shipping so as to reduce the risk of injury to a handler.
Yet another object of the invention is a multiple use method of hanging wall articles.
Other objects and advantages of the present invention will become apparent as a description thereof proceeds.
In satisfaction of the foregoing objects and advantages, the present invention provides a wall article hanging device that is an improvement over prior art types having prongs for attaching a wall article to a wall surface. The invention, in one embodiment, comprising a hanger body having a first end with at least one first opening and a second end with either at least one second opening or at least one article attachment prong. The hanger body has opposing slots, each extending along the hanger body. A prong element is provided that has at least one prong extending outwardly from an element body, opposing edges of the element body sized to engage the opposing slots of the hanger body so that the at least one prong extends outward of the hanger body when the prong element is engaged in the opposing slots.
In one embodiment, the opposing slots can be positioned between the first opening and either the at least one second opening or the at least one article attachment prong.
Alternatively, either the at least one second opening or the at least one article attachment prong is positioned between the opposing slots. The opposing slots can be angled towards the first opening to form a wedge shape or can be generally parallel to each other. The hanger body can be a plate with a pair of curled plate protrusions forming the opposing slots. Each free end of each plate protrusion can be angled with respect to a longitudinal axis of the hanger body so that the formed opposing slots are wedge shaped.
The second end can have a pair of second openings, and the prong element can have two or more prongs.
Depending on the environment of use, one or more than one device can be employed to hang a wall article.
The invention also entails a number of methods of hanging a wall article. In each method, a wall article if first provided and one or more hanger elements are secured to a back surface of the wall article. The securing step is performed by either inserting at least one article attachment prong into the back surface or inserting a fastener, e.g., a nail, screw or the like, through the at least one second opening and into the back surface.
The wall article is then attached to the wall surface by one of: (1) providing a prong element having at least one prong extending therefrom, and inserting edges of the prong element into the opposing slots with the at least one prong angling away from the wall article; and forcing the at least one prong into the wall surface by applying force to the wall article; (2) configuring or bending a portion of the hanger body surrounding the first opening away from the back surface of the wall article, and inserting a free end of an elongate member extending from the wall surface into the first opening to hang the wall article; or (3) providing at least a pair of hanger elements secured to the wall article in a spaced apart relationship, configuring or bending a portion of each of the hanger bodies surrounding each first opening away from the back surface of the wall article, linking a wire between each first opening and using the wire to support the wall article by engagement with at least one elongate member extending from the wall surface.
The hanger body can be first attached to the back surface using the at least one article attachment prong or the second opening, and the prong element can then be attached using the slots. Alternatively, the prong element can be attached first to the hanger element, and the assembled device can be attached to the wall article.
The invention encompasses any means for attaching the prong element to the hanger body for supporting the wall article on a wall using the prong(s) of the prong element, and means permitting separating the hanger body from prong element so that the prong does not extend from the hanger body to create a risk of injury during handling. The means for attaching entail at least the slots on the hanger element and the correspondingly sized prong element to permit the attachment and separation. Other structures achieving these functions are also within the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is now made to the drawings of the invention wherein:
FIG. 1 a is a front view of the hanger body of a first embodiment of the invention;
FIG. 1 b is a side view of the hanger body of the first embodiment of the invention;
FIG. 2 a is a front view of the prong element of the first embodiment;
FIG. 2 b is a side view of the prong element of the first embodiment;
FIG. 3 is a cross section view along the line III—III of FIG. 1 a;
FIG. 4 shows an alternative prong element of the invention;
FIG. 5 is a front view of the second embodiment of the hanger body of FIG. 1;
FIG. 6 is a front view of a third embodiment of the hanger body;
FIG. 7 is a partial front view of a fourth embodiment of the hanger body;
FIG. 8 is a side view of the embodiment of FIGS. 1 a - 2 b in an exemplary use;
FIG. 9 is a side view of a second use of an alternative embodiment to that shown in FIGS. 1 a - 2 b ; and
FIG. 10 is a schematic of a third use of the inventive wall article hanging device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention offers significant advantages in the field of hanging wall articles. The invention overcomes the problems of possible injury due to contact with the prongs of hanging devices. In addition, the inventive wall article hanging device gives the user the option to employ more than one technique to hang a wall article. Thus, a user is not limited to a single technique or system for article hanging, and the user can adapt to the particularities of a hanging location. For example, a nail, moly bolt, or other member may already be in place, and the existing member could be used in conjunction with the inventive hanging device. Alternatively, the wall article could be hung by merely assembling the prong element and hanger body together, and then use the prong element for attachment of the article to the wall.
The protection against injury is significant in terms of being able to attach one part of the inventive wall article hanging device to an article at a remote location, e.g., a manufacturing facility, a wholesaler, even a retailer. At the same time, the other part of the device, the prong element, can be stored separated from the device body in such a position that the prongs do not extend in a manner that could cause injury.
Referring now to FIGS. 1 a - 3 , a first embodiment of a hanger device 10 of the invention is illustrated with FIG. 1 showing the device hanger element or body 1 . The body 1 is elongate in shape, but could have other configurations as well. One end 3 has a generally annular configuration with an opening 5 therein. The opening is circular in shape but other shapes could also be used, e.g., oval, square, etc. Further, the end 3 could have a non-annular shape to form the opening, e.g., be T- or L-shaped, with the extending arms of the T or the arm of the L being serrated to catch a nail in the wall. In this variation, the opening in the end portion is considered to be the open edge of the underside of the arms. When employing the opening 5 , the edge 7 can be rounded to facilitate use of the opening 5 with a wire or the like as described below. The body 1 is preferably made from plate stock.
The other end 9 of the body 1 has a pair of openings 11 , (one or more than two openings could also be used). The openings 11 allow attachment of the body to a wall article for hanging, such as by fasteners, wires, etc.
The hanger body 1 has another segment 13 positioned between the openings 11 in the end portion 9 and the opening 5 in the end portion 3 . The segment 13 has a pair of opposing slots 15 . The slots has ends 17 accommodating both entry and exit.
In this embodiment, the slots 15 can be formed by rolling or curling opposing and protruding ears of the segment 13 , such that the slots are integral with the segment 13 . Of course, other ways may be employed to make the slots, e.g., merely spot weld u-shaped channels to the edges of the segment 13 .
Referring now to FIGS. 2 a and 2 b , a prong element 19 is shown with an element body 21 having a wedge or trapezoidal shape, and a prong 23 extending from the body 21 . The prong 23 can be merely stamped from the body 21 such that a prong-shaped opening (not shown) remains in the body 21 after stamping. The prong element 19 is designed so that it can be separate from the body 1 , or attached thereto. When separated, the prong 23 can be positioned so that the prong end 26 is minimally exposed. When the element 19 is linked to the body 1 , the device is ready for hanging a wall article.
The body 21 is sized in width to slide within the slot openings 25 , see FIG. 3, and is further sized in shape to wedge between the slots 15 . This wedging action keeps the body 21 in place while the wall article is being hung. The wedging action can be attained by sizing the slots 15 to frictionally retain the body 21 after insertion by engagement between the top and bottom of the body 21 and the opposing faces of the slots, but at the same time, allowing the body 21 to be removed if desired. Alternatively, the slots 15 could be crimped at specified intervals along their length to retain the body 21 . The angulation of the body 21 and/or slots 15 can also be adjusted so that the side faces of the body 21 wedge against the opposing faces of the slots 15 .
FIG. 4 shows an alternative removable element 19 ′ with a pair of prongs 23 .
FIG. 5 shows an alternative slot arrangement wherein the slots 15 ′ are parallel to each other rather than angled as shown in FIG. 1 a . In this embodiment, the slot ends 41 can employ a stop to prevent the removable element from sliding out of the slots. The stop can be crimped ends, a wall, a narrowing of the slot width, or the like. This embodiment also employs a reduced thickness portion 42 , which facilitates bending of the end portion 3 as described below for alternative hanging methods.
Another alternative of the device 10 is shown in FIG. 6 . In this embodiment, the openings 11 can be positioned in the segment 13 of the body 1 ″, and the end portion 9 can be eliminated. However, unlike device 10 , the prong element 19 must be removed in order to remove the body 1 ″, that is, the element 19 covers the openings 11 when in the slots 15 . In the FIG. 1 a embodiment, the prong element 19 can remain engaged in the slots 15 while the body 1 is removed from a wall article.
Showing yet another variation, the FIG. 6 embodiment also employs a “D” ring 44 in the end portion. The “D” ring has a loop portion 46 , which rotates in the cylindrical segment 48 , thus allowing the loop portion 46 to move with respect to an adjacent back of a wall article for installation, similar to that shown in FIG. 9 .
Yet another alternative is shown in FIG. 7 wherein the end 3 ′ has a slot 4 to allow access to the opening 5 . The slot 4 permits a wire loop or the like to be inserted around the annular portion 8 of the end portion 3 ′ for attachment purposes as described below.
The inventive wall article hanging device can be used in a number of ways. Referring to FIG. 8, a first way parallels that taught in the Barnes patents noted above. That is, the body 1 is first attached to a wall article 31 using screws 32 extending through the holes 11 . Then, the removable element 19 is inserted into the entry end 17 of the slots 15 so that the prong 23 faces away from both the body 1 and the wall article 31 . The prong 23 is shown inserted at an angle into the wall 33 , and the wall article 31 hangs flushly and generally parallel to the wall 33 .
The separability of the element 19 is advantageous in that the prong 23 can be inserted into the slots 15 just before the wall article 31 is to be hung. With this flexibility, the body 1 can be attached to the wall article 31 well before it is to be hung, e.g., when manufactured or shipped. In this mode, the prong element 19 can be stored separately from the wall article and body 1 or it can attached to the article itself in such a manner that the prong(s) do not extend in a fashion that could cause injury, e.g., taped with the prong end facing a back of the wall article. Attaching the prong element to the article itself is more convenient for the article hanger in that the prong element 19 is readily available for insertion into the slots 15 .
In another mode, referring now to FIG. 9, the opening 5 can be employed for hanging rather than the removable element 19 . In this mode, the end 3 is shown bent away from the wall article using the reduced thickness portion 45 similar to that shown in the FIG. 5 embodiment. This bending can be done either before or after the body 1 ″ is attached to the wall article. Once bent, a space 43 is formed between the end 3 and the back 47 of the wall article 31 . This space 43 allows the end of a nail 49 , a moly bolt, or other elongate element to extend through the opening 5 so that the end 3 is supported by the nail 49 . The end then supports the wall article via the attachment of the body 1 ″ to the wall article 31 .
FIG. 9 also illustrates the body 1 ″ with prong 52 in place of the openings 11 and fasteners 32 as shown in FIG. 8 . The prongs 52 are inserted into the back of the article 31 first, and the same sequence is followed when using the opening 5 for hanging. Of course, the prong 52 can be used in replacement of the fasteners of FIG. 8 if desired. Although one prong is shown, two or more could be employed. Use of the prong as an attachment to the wall article is shown in U.S. Pat. No. 5,328,139.
Although the body 1 can have a necked or reduced thickness as shown in FIG. 5, to facilitate bending of the end 3 with respect to segment 13 , the material and/or overall thickness of the body 1 can be tailored to allow the end 3 to be bent a sufficient degree to form the space 43 for hanging in a more conventional fashion. For example, the material strength could be adjusted to allow for bending without reducing the thickness of the body 1 . The body 1 could be made with a thickness that allows bending.
FIG. 10 shows a schematic of another way to hang a wall article. In this mode, a pair of devices 10 are attached in a spaced apart relationship to the back 47 of the wall article 31 . The openings 5 provide securement points to string a wire or cable between the devices 10 so that the wire can be used to hang the article 31 . In this embodiment, the end 3 may be bent to allow the wire to be inserted into the opening 5 . However, the nature of the article back may allow enough clearance so that the wire can be inserted without bending.
In addition, the use of a pair of devices as shown in FIG. 10 can be employed with the techniques shown in FIGS. 8 and 9. When the prong element 19 utilizes only a single prong, it is preferred to use at least a pair of devices for hanging. The use of at least two prongs helps maintain the article in a level position. If a pair of prongs are employed on the element 19 , a single device may be sufficient for article hanging.
While the mode of FIG. 9 shows that the body 1 is bent to form the space, the body 1 can be configured so that the end portion 3 is slightly angled with respect to at least the segment 13 so that the space 43 is formed once the body is attached to the back of the wall article. Imposing a slight angulation in the end portion 3 removes the need for a user to bend the body 1 .
The material of the device can be any material having sufficient strength to support a wall article, but a preferred material is tempered carbon steel.
While the slots are shown as being angled or wedge shaped, the slots could be parallel as shown in FIG. 5, and one of a wall at the slot end, one or more crimps, slot and/or element 19 sizing, or other stopping configurations can be employed to prevent the removable element from merely sliding through the slot.
Besides entailing a device for hanging articles, the invention also includes methods for hanging wall articles that allow the wall article to be hung using different techniques depending on the preference of the individual and the circumstances surrounding the hanging.
Referring back to the FIGS. 1 a - 3 embodiment, each mode of the invention entails attaching the body 1 to a wall article. As shown in FIG. 8, a pair of screws would be used for fastening, or one or more prongs could be used as well, see FIG. 9 .
In a first mode, once the body 1 is attached to a wall article, the prong element 19 can be inserted into the slots 15 with the prong 23 facing away from the article. Of course, the prong element 19 could be attached to the body 1 prior to attachment of the body 1 to the wall article, if so desired (excepting the FIG. 6 embodiment). The article can be leveled, and the prong 23 is then inserted into the wall by applying a force on the frame of the wall article. The leveling can also be done using the technique described in U.S. Pat. No. 5,758,858.
In a second mode and after the body 1 is attached, the end portion 9 can be bent if the body is a plate, or if using a “D” ring, the ring is rotated away from the back of the wall article. In either case, once a space is created between the opening in the end portion and the wall article back, a nail or other member (previously inserted into the wall) is inserted into the opening in the end portion for wall article support. As noted above, the end portion 3 of the hanger body can already be configured with a slight angle to form the space for hanging using a nail, wire, etc.
In a third mode, a pair of devices can be attached to the wall article in a spaced apart relationship, and a wire can be strung between the openings in the end portion 3 . The wall article can then be hung using the wire and a nail or other member protruding from the wall. In this mode, a wire end can be wrapped around the annular part of the end portion, or a wire loop could be slipped around the annular part 8 shown in FIG. 7 .
While slots are depicted for linking the prong element to the hanger body, other configurations can be employed that will allow the prong element to be connected to the body in such a fashion to allow article support, and be permitted to be easily separated for shipment, storage, etc. As an example, the slots could be discontinuous so that a pair of limited length unshaped channels could be used on either side for prong element retention. These types of channels would still have a slot, just that the slot length would be less than the continuous types illustrated in FIG. 1 a . Other configurations could also be employed as long as the prong element can be separated and/or attached when desired.
As such, an invention has been disclosed in terms of preferred embodiments thereof which fulfills each and every one of the objects of the present invention as set forth above and provides a new and improved wall article hanging device and methods of use.
Of course, various changes, modifications and alterations from the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention only be limited by the terms of the appended claims.
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A wall article hanging device includes a hanger body and a prong element. The hanger body is adapted to attach to the rear of a wall article, and contains opposing slots to receive the prong element. The prong element facilitates attaching the wall article to a wall surface. The prong element is separable from the body element to ease handling of the article prior to article hanging. The hanger body can be used without the prong element for hanging a wall article using items such as a nail and wire.
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FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus and methods for recovering magnetically attractable articles from fluid, and more particularly to an apparatus and methods for recovering magnetically attractable fragments from fluid that has passed through oil and gas well casings to determine the metal loss from the well casings.
BACKGROUND OF THE INVENTION
[0002] Casings used to line wells in oil- and gas-producing formations typically suffer damage from erosion, perforation (such as for the purpose of running additional lines into such a formation), and ordinary wear and tear from the operation of the wells. Since the integrity of well casing is important to the integrity of the well, monitoring the condition of well casing is an important part of well maintenance. Drilling fluid is circulated in well casing for purposes including removing drill cuttings from the casing and from the face of the bit, so one way to monitor the condition of the casing is to collect and analyze the casing fragments released into the drilling fluid. The quantity of casing fragments collected from the drilling fluid is indicative of the quantity of fragments being generated down hole.
[0003] Solids and cuttings are generally removed from drilling fluids at the surface by solids control equipment such as shale shakers and hydrocyclones, which dump solids into collection bins. It is known to place a “ditch magnet” into the drilling fluid system to collect casing fragments from the drilling fluids. The shale shaker is a device in an oil well drilling process used to collect oversize drill cuttings, etc. from drilling fluid. The shale shaker is monitored for metal filings to assess metal wear such as for example, casing wear. For monitoring the metal wear, a shale shaker magnet is often used to magnetically attract and collect thereon at least a portion of metal filings that enter the shale shaker. The magnets are periodically removed from the shale shaker and the metal filings collected therefrom and weighed in order to quantify the filings that have been collected in the time period. The quantity of filings that are collected are indicative of the amount of metal filings passing into the shale shaker and, therefore, also indicative of the amount of metal filings being generated down hole.
[0004] The typical ditch magnet is heavy, and requires at least two persons to lower it into the drilling fluid stream. As metal fragments adhere to the ditch magnet, the device becomes even heavier and difficult for personnel to remove. Removal of the metal particles from the ditch magnet is difficult because of the strong magnetic field, which can also result in the magnetization of handles or other features of the device. Drilling personnel usually run their hands over the surface of the ditch magnet in an effort to strip the magnetic materials from the magnet. In prior art devices, the handle often complicates the collection of the magnetic materials attracted about it. The collection process becomes slow and laborious, and the completeness of the collection process can vary from person to person and from time to time because of the added complexity of removing the collected materials about the handle. Thus, the amount of metal fragments retrieved and therefore the accuracy of the calculation of total metal loss in the casing depends on the skill and thoroughness of the personnel removing the fragments from the ditch magnets.
[0005] Another known method of fragment removal employs shrouded or sheathed magnets in a non-magnetic housing which includes a lid connectable to the housing so that the magnets are removable from the housing. By removing the magnets from the housing, the housing can be demagnetized to facilitate collection of the metal filings from the exterior surface of the housing. However, the connection between the lid and the housing can become fouled by drilling mud and metal filings so that the reconnection of the lid to the housing becomes difficult. There is a need for an apparatus and method for inexpensive removal of casing fragments from drilling fluids without the disadvantages of the known devices and methods.
SUMMARY OF THE INVENTION
[0006] The present invention is directed to methods and apparatus for removing casing fragments from fluids circulated in hydrocarbon-producing wells.
[0007] In one aspect, the invention is directed to a method for monitoring the condition of well casing by recovering magnetically attractable casing fragments from fluid in a vessel having an upper end, including placing a reusable magnetic separator in the fluid in the vessel, wherein the separator includes a magnetic body, at least one nonmagnetic end contiguous to the body, an exterior surface spanning the body and nonmagnetic end, and a hanger; retaining the separator in the fluid for a selected period of time; removing the separator from the vessel; and urging the casing fragments along the exterior surface of the separator to the nonmagnetic end and collecting them. In another aspect, the invention is directed to a magnetic separator, having a bare magnet body, at least one nonmagnetic end contiguous to the body, and an exterior surface spanning the body and nonmagnetic end.
[0008] It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable for other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Referring to the drawings wherein like reference numerals indicate similar parts throughout the several views, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein:
[0010] FIG. 1A is a side elevation of an embodiment of an apparatus according to the present invention.
[0011] FIG. 1B is a perspective view of another embodiment of an apparatus according to the disclosed invention.
[0012] FIG. 2 is a schematic view of a device and a method according to the disclosed invention.
[0013] FIG. 3 shows an exploded isometric view of an embodiment the disclosed invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0014] The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
[0015] Referring to FIG. 1A , one apparatus according to the invention is a reusable magnetic separator 10 for retrieving metal fragments from hydrocarbon well fluids including a magnet body 12 contiguous to at least one nonmagnetic end 14 , and an exterior surface 16 .
[0016] In some embodiments of the invention, the separator may include more than one nonmagnetic end. In other embodiment, the separator may be connectable to one or more hangers, for suspension thereof in use. The hanger may include a cable, a rope, a chain, or other conventional materials. Where more than one hanger is used, the points of connection of the hanger may be spaced apart and furthermore the points of connection of the hangers may each be disposed at a nonmagnetic end.
[0017] Referring to FIG. 1B , another reusable magnetic separator 10 a is shown. Reusable magnetic separator 10 a is formed as an elongate member including a magnetically attractant body 12 a , a first nonmagnetic end 14 a ′ and an opposite nonmagnetic end 14 a ″. A first connector 15 a ′ is positioned at first nonmagnetic end 14 a ′ for accepting connection of a hanger (not shown) and a second connector 15 a ″ is positioned at the opposite nonmagnetic end for connection of a second hanger (not shown). The first and the second connectors may be in the form of eyebolts, as shown. Body 12 a and ends 14 a ′ and 14 a ″ are contiguous and formed by a housing 17 a that extends about the separator. Housing 17 a contains therein one or more magnetic sources, illustrated herein as bar magnets 22 a , forming the magnetic body 12 a . The magnets 22 a do not extend into the housing at its ends forming nonmagnetic ends 14 a ′, 14 a ″. Housing 17 a may have a surface that is substantially smooth and substantially free of protrusions along its sides.
[0018] Referring to FIG. 2 , a method of the invention includes placing a reusable magnetic separator 10 b into fluid 28 in a vessel 20 , such as a shale shaker, and retaining the separator 10 b in the fluid 28 for a selected period of time; the magnetic field separates and magnetically collects the casing fragments 30 and other magnetically attractable materials from the fluid 28 . After a suitable selected period of time, the separator 10 b is removed from the vessel 20 and the collected materials are collected from the separator. To release the casing fragments 30 from the separator 10 b , the casing fragments 30 are urged along the exterior surface 16 b to the nonmagnetic end 14 b , when they are no longer attracted to, and will fall away from, the separator. If the separator includes more than one nonmagnetic end, the magnetically attractable casing fragments may be collected by urging them to either or both nonmagnetic ends. The recovered casing fragments 30 may be analyzed (qualitatively and/or quantitatively) to assess the condition of the well casing.
[0019] As shown in FIG. 2 , in some embodiments, the separator 10 b may be suspended in the fluid 28 with one or more hangers 18 a . In various embodiments of the invention, the length of the hanger or hangers may be selected to maintain the separator above the bottom of the vessel. Since a shale shaker may accumulate settled materials, suspending the separator may facilitate collection of materials thereon as the separator is held up out of the accumulated materials and open in the flow of the fluid moving therepast. The selected length of the hanger may be fixed in some embodiments of the inventive methods so that when the separator is removed and repositioned within the vessel, it is suspended at the same position within the vessel each time.
[0020] Another aspect of the invention is a method for monitoring the condition of well casing by recovering magnetically attractable casing fragments from drilling fluid returning from the well, wherein the casing fragments may be generated by use or modification of the well casing. In this method, a reusable magnetic separator having a magnetic body and a nonmagnetic end contiguous to the body is placed in drilling fluid contained in a vessel, such as a shale shaker, whereby magnetically attractable casing fragments are separated from the fluid by the magnetic field created by the magnetic body. After a suitable selected period of time, the separator is removed from the fluid, and the casing fragments are urged along the exterior surface of the separator to the nonmagnetic end where they can be removed easily. The magnetic separator used in some embodiments may include a housing substantially free of protrusions along its sides and containing bar magnets, at least one nonmagnetic end, an eye bolt on the at least one nonmagnetic end attaching such nonmagnetic end to a hanger (such as a chain or other hanger type). In some embodiments, the collected casing fragments may be weighed after each of a number of similar time periods such that the amounts collected per time period may be compared over time. In another embodiment, weight of the recovered casing fragments may calculated and compared to a total weight of the casing originally installed in the well, which may be known or calculated, so that the percent of metal lost from the casing is obtainable for example by dividing the weight of the casing fragments recovered from the well by the total weight of the casing originally installed in the well. The casing fragments may also be subjected to qualitative assessment, such as by visual inspection.
[0021] Yet another aspect of the invention is a method for collecting magnetically attractable particles from fluid including placing a reusable magnetic separator in fluid, wherein the separator includes a magnetic body which in turn may have bare magnet, at least one nonmagnetic end contiguous to the body, and an exterior surface spanning the body and the nonmagnetic end; retaining the separator in the fluid for a selected period of time; removing the separator from the fluid; and, urging the particles along the exterior surface of the separator to the nonmagnetic end and collecting them.
[0022] Referring to FIG. 3 , in some embodiments of the invention the body 12 c may include at least one magnet 22 , and each magnet 22 may have a bore 26 such that the bores 26 of adjacent magnets 22 are aligned along an axis and a retainer 24 can be inserted through the bore 26 of each magnet 22 . At least one end of the retainer 24 may be attached to a nonmagnetic end 14 c , which nonmagnetic end is further attached by a connector to a hanger 18 .
[0023] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope as defined in the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are know or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 USC 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or “step for”.
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Methods and apparatus are disclosed for recovering magnetically attractable wellbore casing fragments from drilling fluid used in hydrocarbon-producing formations.
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TECHNICAL FIELD
[0001] The present invention relates generally to shock absorbers for use in protective structures such as body gear, and more particularly to fluid-filled compressible cells.
BACKGROUND
[0002] During sports and other physical activity, individuals are often exposed to impact forces that, if not at least partially attenuated, can cause severe injury. Therefore, they usually wear protective sporting gear, such as helmets, shields, elbow and knee pads, etc. Such protective gear typically includes impact-attenuating structures that deform elastically and/or plastically in response to an impact force, thereby mechanically attenuating the impact. For example, many helmets have a crushable foam layer disposed between a rigid or semi-rigid outer shell and an inner liner that conforms the helmet to the wearer's head.
[0003] Foams are generally customized to respond optimally to a specific range of impact energies, but outside this range, their effectiveness is significantly reduced. For impact energies exceeding the high end of the range, the foam is too soft and “bottoms out”—i.e., reaches maximum compression—before the impact is fully attenuated, resulting in the transfer of high impact forces to the body. For impact energies below the optimal range, on the other hand, the foam is too hard to compress, or “ride down,” sufficiently to adequately prolong the distance and time over which deceleration occurs following impact, resulting in sudden, high peak forces. The only way to improve the impact-attenuating capability of a foam layer is, typically, to decrease the density of the foam (i.e., make it softer) and increase the thickness of the layer, which results in an undesirable increase in the amount of material used. Exacerbating this trade-off, the maximum ride-down distance for most foams is only about 30-40% of the original height. Thus, about 60-70% of the foam layer add to the bulk and weight, but not the impact-absorption capacity, of the protective structure. In addition, the performance of many foams degrades rapidly with repeated impacts. Other conventional impact-absorbing layers exhibit similar problems and limitations.
[0004] More recent helmet designs feature, in place of a continuous layer, discrete fluid-filled compression cells, which resistively vent a fluid through an orifice of the cell enclosure to attenuate the impact. These cells generally have ride-down distances close to their height, exhibit superior durability, and adapt to a wide range of impact energies. Furthermore, they provide opportunities for tailoring the impact-absorption characteristics of the helmet (or other protective structure) via the cell design. Such customization opportunities, however, have rarely been exploited.
SUMMARY
[0005] The present invention provides shock absorbers for integration into protective structures, such as, for example, helmets and other protective body gear, as well as dashboards, shock-absorbing seating, and safety padding in vehicles, sporting equipment, and machinery. The shock absorbers generally take the form of hollow, fluid-filled, compressible cells. In preferred embodiments, the cell enclosure includes one or more orifices, or vents, through which a fluid (such as air or water) can escape from the inner chamber formed by the enclosure. Such compression cells utilize, simultaneously or in sequence, two impact-attenuating mechanisms: resistance of the cell enclosure to compression, and resistive fluid-venting through the orifice(s). In some embodiments, the cell attenuates impact forces by resisting compression at least initially through both the enclosure (or walls) and the fluid. Following an initial stage of the impact, the walls may yield to allow the remainder of the impact to be attenuated via resistive fluid-venting. The enclosure may include features that increase resistance to compression as the cell approaches the fully compressed state. Various embodiments of the present invention are directed to improving the energy management characteristics of the shock absorbers by tailoring the structure and shape of the enclosure, and/or the size and shape of the vents.
[0006] The compression cells may include top, bottom, and side walls, and may (but need not necessarily) be symmetrical around an axis through the center points of the top and bottom walls. For example, the cells may be disk-shaped or cylindrical. The side walls may be, without limitation, straight, angled, curved, or frustoconical, depending on the impact absorption profile desired for the particular application. In certain embodiments, two frustoconical portions of the side walls are arranged back-to-back such that the walls toe in toward a medial plane, accelerating the reduction of the inner volume as the cell collapses. The exterior shape of the cell may be adjusted to the protective structure in which it is integrated. For example, shock absorbers for use in helmets may have rounded (rather than planar) top walls to better fit between the interior liner and the shell, and/or side walls that taper toward one side to better accommodate the narrow space along the periphery of the helmet.
[0007] The wall or walls of the shock absorber may be of uniform or varying thickness, depending on the desired shock absorption profile. For example, in some embodiments, the side walls increase in thickness from the top wall toward the bottom wall, resulting in increased resistance as the top wall approaches the bottom wall during compression. In other embodiments, the side walls decrease in thickness toward the bottom, which may result in shearing of the cell during the initial phase of the impact, followed by compression. Further, corrugations in and/or structures protruding from the top and/or bottom walls may contact the opposing wall during a late stage of compression, thereby effectively increasing the number of side walls that contribute to impact absorption.
[0008] In some embodiments, the enclosure includes features that alter the rate of fluid-venting through the orifice. For example, a pin at the bottom wall may engage with (i.e., partially or totally plug) an orifice through the top wall so as to obstruct the latter when the shock absorber is compressed. Alternatively, the rim around the orifice may extend into an open tube that impedes fluid flow when it makes contact with the opposing wall. In certain embodiments, the orifice is equipped with a check valve or other structure that regulates fluid flow. These and similar features may be used individually or in various combinations to customize the shock-absorption characteristics of the compression cell.
[0009] Accordingly, in a first aspect, the invention relates to a compressible cell for attenuating impact forces imparted thereto. In various embodiments, the cell comprises an enclosure defining an inner chamber for containing a fluid; the enclosure includes a side wall, extending and varying in thickness between a top wall and a bottom wall, that resistively yields in response to an impact imparted to the top wall. The side wall may increase or decrease in thickness from the top to the bottom wall. The resistance of the yielding side walls may increase with increasing energy of the impact and/or increased compression of the side wall. The cell may shear in response to a non-perpendicular impact force. In various embodiments, the cell further comprises at least one orifice in the enclosure for resistively venting fluid from the inner chamber so as to at least partially attenuate the impact when the side wall yields.
[0010] In another aspect, the invention relates to a method involving a safety article that comprises a compressible cell including an enclosure defining an inner chamber and having a side wall extending and increasing in thickness between a top wall and a bottom wall, where the safety article is worn on a body with the bottom wall closer to the body than the top wall. The method is directed toward protecting the body from damage due to impacts and comprises, in various embodiments, attenuating an impact imparted on the top wall at least partially with the side wall by resistively yielding, where resistance to yielding increases with increased compression of the side wall. In various embodiments, the enclosure has an orifice and the method further comprises attenuating the impact at least partially by venting fluid from the inner chamber through the orifice.
[0011] In a further aspect, the invention relates to a method involving a safety article that comprises a compressible cell including an enclosure defining an inner chamber and having a side wall extending and decreasing in thickness between a top wall and a bottom wall, where the safety article is worn on a body with the bottom wall closer to the body than the top wall. The method is directed toward protecting the body from damage due to impacts and comprises, in various embodiments, attenuating a tangential component of an impact imparted on the top wall at least partially by shearing, and attenuating a normal component of the impact imparted on the top wall at least partially with the side wall by resistively yielding. In some embodiments, the enclosure has an orifice and the method further comprises attenuating the impact at least partially by venting fluid from the inner chamber through the orifice.
[0012] In another aspect, the invention pertains to a compressible cell for attenuating impact forces imparted thereto. In various embodiments, the cell comprises an enclosure defining an inner chamber for containing a fluid; the enclosure comprises a top wall including corrugations around a periphery thereof, a bottom wall, and a side wall extending between the top and bottom walls. The side wall and corrugations of the top wall resistively yield in response to an impact imparted to the top wall so as to attenuate impact forces while allowing the cell to compress. In various embodiments, the cell further comprises at least one orifice in the enclosure for resistively venting fluid from the inner chamber so as to at least partially attenuate the impact. The corrugations may increase resistance to compression of the cell as they contact the bottom wall. In various embodiments, the top wall is configured to allow lateral movement of a center region thereof relative to a periphery thereof. Furthermore, the side wall may vary in thickness between the top wall and the bottom wall.
[0013] The cell may be configured for use between an exterior shell and an interior liner of an impact-attenuating helmet, in which case the top wall may be domed so as to conform to the inner surface of the exterior shell. Moreover, the enclosure may be tapered at the top wall so as to fit between the shell and the liner in a peripheral region of the helmet.
[0014] In still a further aspect, the invention relates to a method involving a safety article that comprises a compressible cell including an enclosure defining an inner chamber, a top wall having corrugations around a periphery thereof, a bottom wall, and a side wall extending between the top and bottom walls. The safety article is worn on a body with the bottom wall closer to the body than the top wall. The method is directed toward protecting the body from damage due to impacts and comprises, in various embodiments, attenuating an impact imparted on the top wall at least partially with the side wall and the corrugations of the top wall by resistive yielding thereof. In some embodiments, the enclosure has an orifice and the method further comprises attenuating the impact at least partially by venting fluid from the inner chamber through the orifice.
[0015] In yet another aspect, the invention pertains to a compressible cell for attenuating impact forces imparted thereto, and which, in various embodiments, comprises an enclosure defining an inner chamber for containing a fluid; the enclosure comprises at least one side wall extending between a top wall and a bottom wall, and the side wall(s) resistively yield in response to an impact imparted to the top wall so as to allow the cell to compress. The top wall and/or the bottom wall comprises vertically extending features that increase resistance to compression of the cell as the top wall approaches the bottom wall. In some embodiments, the cell further comprises at least one orifice in the enclosure for resistively venting fluid from the inner chamber so as to at least partially attenuate the impact. The features may comprise corrugations around a periphery of the top wall and/or a plurality of concentrically arranged ridges on the bottom wall. In some embodiments, the side wall varies in thickness between the top wall and the bottom wall. The cell may be configured for use between an exterior shell and an interior liner of an impact-attenuating helmet, with the top wall being domed so as to conform to the inner surface of the exterior shell. The enclosure may be tapered at the top wall so as to fit between the shell and the liner in a peripheral region of the helmet.
[0016] In still a further aspect, the invention relates to a method involving a safety article that comprises a compressible cell including an enclosure defining an inner chamber, a side wall, and top and bottom walls at least one of which includes vertically extending features. The safety article is worn on a body with the bottom wall closer to the body than the top wall. The method is directed toward protecting the body from damage due to impacts and in various embodiments comprises, in response to an impact imparted to the top wall, attenuating the impact at least partially with the side wall by resistive yielding thereof; and attenuating the impact at least partially with the vertically extending features as the top wall approaches the bottom wall. The enclosure may have an orifice, and the method may further comprise attenuating the impact at least partially by venting fluid from the inner chamber through the orifice.
[0017] In a further aspect, the invention pertains to a compressible cell for attenuating impact forces imparted thereto, and which, in various embodiments, comprises an enclosure defining an inner chamber for containing a fluid; the enclosure compresses in response to an impact. The cell also includes at least one orifice in the enclosure for resistively venting fluid from the inner chamber during the compression so as to at least partially attenuate the impact, and a valve for partially obstructing the orifice so as to increase resistance to the compression. In various embodiments the enclosure comprises top and bottom walls, and the resistance to the compression of the cell is increased by the partial obstruction of the orifice as the top wall approaches the bottom wall. Some or all of the walls may resistively yield in response to the impact, thereby partially attenuating the impact while allowing the cell to compress. In various embodiments, the valve comprises a pin protruding from the bottom wall opposite the orifice, where the pin, in a compressed state of the cell, engages the orifice so as restrict fluid venting therethrough. Alternatively, the valve may comprise a tubular protrusion extending downward from the top wall and surrounding the orifice. The tubular protrusion self-restricts the orifice due to increased fluid turbulence.
[0018] Yet another aspect of the invention relates to a method involving a safety article that comprises a compressible cell that includes an enclosure defining an inner chamber and having an orifice and a valve therein. The method is directed toward protecting the body from damage due to impacts and comprises, in various embodiments, attenuating an impact imparted on the enclosure at least partially by resistively venting fluid from the inner chamber through the orifice, whereby the enclosure compresses, during compression of the enclosure, increasing a resistance to compression by partially and increasingly obstructing the orifice with the valve.
[0019] Still another aspect of the invention pertains to a compressible cell for use between an exterior shell and an interior liner of an impact-attenuating helmet. In varioius embodiments, the cell comprises an enclosure comprising a top wall, a bottom wall, and at least one side wall that resists yielding in response to an impact at least during an initial phase thereof, the enclosure defining an inner chamber for containing a fluid; and at least one orifice in the enclosure for resistively venting fluid from the inner chamber so as to at least partially attenuate the impact after the initial phase, wherein the top wall is domed so as to conform to an inner surface of the exterior shell.
[0020] In yet another aspect, the invention relates to a protective helmet comprising an exterior shell, an interior liner placed inside the shell, and, disposed between the shell and the liner, at least one compressible cell comprising (i) an enclosure defining an inner chamber and comprising a top wall, a bottom wall, and side walls that resist yielding in response to an impact at least during an initial phase thereof, the top wall being domed so as to conform to an inner surface of the exterior shell, and (ii) at least one orifice in the enclosure for resistively venting fluid from the inner chamber so as to at least partially attenuate the impact after the initial phase.
[0021] In a further aspect, the invention pertains to a compressible cell for use between an exterior shell and an interior liner of an impact-attenuating helmet. In various embodiments, the cell comprises an enclosure including a top wall, a bottom wall, and side walls that resist yielding in response to an impact at least during an initial phase thereof, the enclosure defining an inner chamber for containing a fluid; and at least one orifice in the enclosure for resistively venting fluid from the inner chamber so as to at least partially attenuate the impact after the initial phase, wherein the enclosure is tapered at the top wall so as to fit between the shell and liner in a peripheral region of the helmet.
[0022] In another aspect, the invention relates to a protective helmet comprising an exterior shell; an interior liner placed inside the shell, where the distance between the exterior shell and the liner decreases in a peripheral region of the helmet; and disposed between the shell and the liner, at least one compressible cell comprising (i) an enclosure defining an inner chamber and comprising a top wall, a bottom wall, and side walls that resist yielding in response to an impact at least during an initial phase thereof, the enclosure being tapered at the top wall so as to fit between the shell and the liner in the peripheral region of the helmet, and (ii) at least one orifice in the enclosure for resistively venting fluid from the inner chamber so as to at least partially attenuate the impact after the initial phase.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The foregoing will be more readily understood from the following detailed description, in particular, when taken in conjunction with the drawings, in which:
[0024] FIG. 1A is a schematic cross-sectional view of a shock absorber enclosure in accordance with one embodiment, which features side walls including an exterior obtuse angle and increasing in thickness toward the bottom plate;
[0025] FIG. 1B is a schematic cross-sectional view of a shock absorber enclosure in accordance with one embodiment, which features side walls including an exterior obtuse angle and decreasing in thickness toward the bottom plate;
[0026] FIG. 1C is a schematic cross-sectional view of a shock absorber enclosure in accordance with one embodiment, which features side walls of uniform thickness that include an interior obtuse angle;
[0027] FIG. 2A is a schematic cross-sectional view of a shock absorber enclosure in accordance with one embodiment, which features corrugations in the top wall;
[0028] FIG. 2B is a schematic cut-away view of a shock absorber enclosure in accordance with one embodiment, which features nested cylindrical walls protruding from the bottom wall;
[0029] FIG. 3A is a is a schematic cross-sectional view of a shock absorber enclosure in accordance with one embodiment, which features a pin protruding from the bottom wall opposite an orifice through the top wall;
[0030] FIG. 3B is a schematic cross-sectional view of a shock absorber enclosure in accordance with one embodiment, which features a tubular protrusion extending from the top wall and surrounding an orifice therethrough;
[0031] FIG. 4 is an elevational view of a protective helmet with multiple distributed compression cells in accordance with one embodiment.
[0032] FIGS. 5A is a perspective sectional view of a shock absorber enclosure in accordance with one embodiment, side walls of varying thickness, a rounded top wall, and corrugations along the circumference of the top wall;
[0033] FIG. 5B is a perspective sectional view of a shock absorber enclosure similar to that of FIG. 5A , which further tapers off toward one side so as to better fit into peripheral space of a protective helmet; and
[0034] FIG. 5C is a sectional view of a shock absorber enclosure in accordance with another embodiment, which features varying wall thickness, corrugations along the circumference of the top wall, and a valve protruding from the top wall.
DETAILED DESCRIPTION
[0035] Shock absorbers in accordance herewith can be fabricated from a variety of elastic and semi-elastic materials, including, for example, rubbers, thermoplastics, and other moldable polymers. A particularly suited material, due its durability, resiliency, and amenability to blow molding or injection molding, is thermoplastic elastomer (TPE); commercially available TPEs include the ARNITEL and SANTOPRENE brands. Other materials that may be used include, for example, thermoplastic polyurethane elastomers (TPUs) and low-density polyethylene (LDPE). In general, the material selection depends on the particular application, and can be readily made, without undue experimentation, by a person of skill in the art based on known material properties. Further, the desired shape and configuration of the shock absorber enclosure can generally be created using any of a number of well-known manufacturing techniques, such as, e.g., blow molding or injection molding. The shock absorber may be manufactured in one piece, or in two or more parts that are subsequently bonded together to form a fluid-tight enclosure. Bonding may be accomplished, for example, with an adhesive (such as glue), or using a thermal bonding process. Mechanically interlocking features, clamps, or similar devices may be used to assure that the multiple parts remain affixed to each other.
[0036] FIG. 1A schematically illustrates an exemplary shock absorber cell 100 in accordance with various embodiments. The cell includes a flat bottom plate 102 and, secured thereto, a cap 104 forming the top wall 106 and side walls 108 of the structure. An orifice or vent 110 through the top wall 106 allows fluid to exit from the interior chamber 112 formed by the cell enclosure as the cell is compressed during an impact, as well as to enter the chamber as the cell returns to its original shape following the impact. Although only one orifice is shown, various embodiments use multiple orifices of the same or different shapes and sizes. The orifice(s) need not go through the top wall, but may generally be located in any portion of the cell enclosure. Further, instead of being simple holes or slits, the orifices may be equipped with valve structures that regulate flow therethrough. For example, in some embodiments, check valves that allow only inflow are provided at the bottom wall of the cell, and check valves that permit only outflow are included in the top wall, or vice versa.
[0037] Returning to FIG. 1A , the side walls 108 form two back-to-back frustoconical portions that meet with their narrower end at a horizontal plane located between the top and bottom walls 106 , 102 , such that they define an obtuse exterior angle α. Thus, when the cell 100 collapses, the side walls 108 move inward toward a central axis 114 of the cell, thereby reducing the volume of the cell and further compressing the air therein. This may result in increased turbulence of the air escaping through the orifice 110 and, thus, in increased resistance to compression. Further, as shown, the side walls 108 increase in thickness between the top and bottom walls. As a result, the resistance that the walls 108 themselves provide to the impact increases steadily throughout the duration of the compression. As will be readily apparent to one of skill in the art, variations of the wall thickness along its height can generally be used to tailor the temporal energy management profile of the cell, as characterized, for example, in terms of the residual force transmitted through the cell as a function of time.
[0038] FIG. 1B illustrates an alternative compression cell 120 , in which the thickness of the side walls 128 increases toward the top wall 106 . (Other than that, the cell 120 is similar to the cell 100 depicted in FIG. 1A .) The thin portion 130 of the wall 128 near the bottom plate 102 constitutes a “weak spot” of the cell enclosure, which allows the cell to initially shear in response to an impact force that includes a component parallel to the top surface (i.e., a tangential force), thereby dissipating tangential forces. During later phases of the impact, energy is absorbed via compression of the thicker wall portions near the top wall 106 .
[0039] FIG. 1C shows yet another shock absorber structure 140 , which includes walls of substantially uniform thickness. In this embodiment, the side walls 148 are angled so as to define an interior obtuse angle β, and, consequently, they collapse outwardly. Accordingly, the cell enclosure provides somewhat lower resistance to collapse then that of the cells 100 , 120 with inverted walls depicted in FIGS. 1A and 1B . These and other cell wall designs may be combined with additional features as described below.
[0040] In some embodiments, the top and/or bottom walls of the shock absorber are not flat (as depicted in FIGS. 1A-1C ), but include corrugations or features vertically protruding therefrom. Such features can provide increased resistance during late stages of cell compression. For example, FIG. 2A shows a shock-absorber cell 200 with one or more “V-shaped” corrugations 202 around a periphery of the top wall 204 . As the cell is 200 compressed, the top wall 204 approaches the bottom wall 206 , and the lowest points 208 of the corrugations 202 eventually contact the bottom wall 206 . Effectively, this increases the number of side walls against which the impact forces work and, thus, inhibits further compression of the cell 200 . As a result, the shock absorber cell 200 can withstand larger impact forces before it bottoms out. Moreover, flexure of the corrugations 202 facilitates lateral motion of the center region of the top wall 204 relative to the periphery in response to shear forces. Thus, in addition to increasing the cell's resistance to normal forces, the corrugations 202 help dissipating shear forces.
[0041] FIG. 2B illustrates another design for a shock-absorbing cell 220 , in which a plurality of concentric circular ridges 222 are arranged on the bottom wall 224 . When the top wall reaches these ridges 222 during compression of the cell 220 , the ridges 222 begin contributing to the absorption of the impact, resulting in a higher overall resistance of the shock absorber to compression. The above-described corrugations and vertically protruding features are merely examples; corrugations and protrusions of different shapes and configurations, attached to the top wall, the bottom wall, or both, may likewise be used to achieve similar effects.
[0042] FIGS. 3A and 3B illustrate shock absorbers in which the configuration of the orifice and, consequently, the rate of fluid flow therethrough change depending on the compression state of the cell. For example, FIG. 3A shows a compression cell that includes a long, conical pin 302 protruding from bottom wall 304 opposite an orifice 306 through the top wall 308 . Once the cell 300 has been sufficiently compressed in response to the impact (e.g., to about half its original height as shown in the figure), the pin 302 is received within and penetrates the orifice 306 , thereby reducing the area through which fluid can escape. Eventually the pin 302 completely obstructs the orifice, preventing any further fluid-venting. Thus, the orifice 306 and pin 302 together function as a valve.
[0043] FIG. 3B shows an alternative embodiment 320 , in which valve-like behavior is created by a tubular protrusion 322 that extends vertically downward from the top wall 324 and includes a lumen 326 therethrough. The tubular protrusion 322 can restrict fluid-venting via two mechanisms. As can be readily seen, fluid venting through the lumen 326 requires the fluid to enter the tube 322 at the end 328 close to the bottom wall 330 . Accordingly, as this end 328 contacts the bottom wall, venting is precluded or at least inhibited. In addition, and generally more importantly, the tube 322 can be made of a thickness and material that allows it to constrict and self-restrict the orifice in response to increased fluid turbulence, much like a balloon that releases air through the opening.
[0044] Shock absorbers as described above may employed advantageously in a variety of applications, including, for example, protective body gear, vehicle dash boards, and shock-absorbing seats. FIG. 4 illustrates, as one exemplary application, a protective helmet 400 including multiple compression cells 402 distributed between a shell and a helmet liner. The shock absorbers 402 may include any combination of the features described above. Further, they may be shaped to accommodate the space between the shell and liner. For example, FIG. 5A shows a shock absorber cap 500 A (omitting the bottom wall) that has an elevated, rounded top wall 502 with a curvature complementary to that of the interior surface of the helmet shell. Further, the shock absorber features one or more “V-shaped” corrugations 202 around the periphery of the top wall 502 , and inwardly angled side walls 505 with that increase in thickness toward the bottom. The rounded top wall and corrugation(s) cooperate to allow the cell top to shift laterally in response to shear forces.
[0045] FIG. 5B illustrates a shock absorber 500 B suitable for use in areas of the helmet that curve back in toward the head, e.g., the occipital lock area on the back of the helmet and the areas on the lower sides. The shock absorber 500 B has an elevated, rounded top wall 502 with a curvature complementary to that of the interior surface of the helmet shell. Further, the shock absorber features one or more “V-shaped” corrugations 202 around the periphery of the top wall 502 , and inwardly angled side walls 505 with that increase in thickness toward the bottom. The enclosure of this shock absorber tilts toward one side, i.e., the side wall height decreases across a diameter of the shock absorber such that, properly placed, it sits flush against the shell. The shock absorber 500 B includes a tubular protrusion 322 that extends vertically downward from the top wall 502 and includes a lumen therethrough. The radial grooves illustrated in FIGS. 5A and 5B are vents that permit air to travel over the surface of the shock absorber upon impact.
[0046] FIG. 5C illustrates another shock-absorbing cell 500 C having side walls whose collective height decreases across a diameter of the shock absorber to conform to a space of non-uniform height. This cell combines side walls 502 toeing in toward a medial plane and increasing in thickness toward the bottom, corrugations 202 in the top wall, and a plurality of concentric circular ridges 222 arranged on the bottom wall 506 . These features cooperate to increase the cell's resistance to compression as a highly compressed state is reached and, thus, collectively increase the energy levels that can effectively be absorbed without increasing the height of the shock absorber structure.
[0047] Certain embodiments of the present invention are described above. It is, however, expressly noted that the present invention is not limited to those embodiments; rather, additions and modifications to what is expressly described herein are also included within the scope of the invention. Moreover, it is to be understood that the features of the various embodiments described herein are not, in general, mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations are not made express herein, without departing from the spirit and scope of the invention. In fact, variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention. As such, the invention is not to be defined only by the preceding illustrative description.
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Shock absorbers for integration into protective structures generally take the form of hollow, fluid-filled, compressible cells. In various embodiments, the cell enclosure includes one or more orifices, or vents, through which a fluid (such as air or water) can escape from the inner chamber formed by the enclosure.
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FIELD OF THE INVENTION
This invention relates generally to data processors, particularly to integrator and differentiator circuits.
BACKGROUND OF THE INVENTION
Many signal processing designs require hardware arithmetic support in the form of dedicated adders, subtracters, and multipliers. These operations generally have to be completed in a specified amount of time and with a minimum of circuitry. Typically, these operations require operands and/or results of several digits (bits, in a binary structure) arranged in monotonically increasing orders of magnitude. A need for such circuits has grown in response to demands of digital signal processing and complex analog-to-digital and digital-to-analog converters. As system requirements become more stringent, the number of digits required for an operation increases accordingly.
There are two standard forms of adders. One is the ripple-carry adder, in which each stage provides a carry bit or digit to the following stage. Thus, each digit of the result is dependent on the results of a computation performed on a lower adjacent digit. In this structure, the Nth digit cannot be calculated until the (N--1)th operation is completed. While this is a very space-efficient approach, with the size of the structure increasing linearly with the number of digits required, the speed at which the calculation can be performed is limited by this restriction and is often unacceptable in high-speed systems with wide data paths. The other standard form is the carry look-ahead adder, which bases its calculation for each digit not on outputs of the previous stages, but on inputs to previous stages. In this type of structure speed is enhanced, since each stage of the adder can perform its calculations simultaneously, without waiting for previous stages to complete; however, each successive stage requires approximately twice the circuitry of that preceding it. The complexity of the structure thus grows exponentially with the number of bits or digits in the data path, and is often unwieldy or completely impractical for large data paths. Further, technological restrictions on gate widths often force a compromise on higher-order stages, limiting operational speed.
It is not uncommon for the above two standard adder forms to be combined into a partial look-ahead adder comprised of N ripple-carry stages of M digits each, the M digits being organized into a traditional look-ahead structure. This has neither the speed of a full look-ahead implementation, nor the space efficiency of a ripple-carry structure, but represents a trade-off between the two.
There is a need for an accumulation apparatus that is more efficient than the combination of the two standard forms, and that simultaneously maintains a relatively low level of hardware complexity.
SUMMARY OF THE INVENTION
A data processing apparatus and method for processing input data, are included, comprising at least: a plurality of first latching unit coupled in a cascade fashion for data flow from selected first latching unit to further selected pre-stage latching unit, where desired, then to data processors (DP) having: first outputs that feedback to selected pre-stage, third latching means, second outputs that are provided to second latching unit for carry, and third outputs for data flow, wherein the second latching means are coupled between selected data processing unit for allowing selected feedforward of data and wherein the pre-stage third latching unit coupled between selected data processing unit and selected pre-stage latching unit for storing selected data processing unit feedback outputs for utilization in subsequent data processing; data processing unit coupled between preselected post-stage latching unit, where desired, and pre-stage latching unit for performing a predetermined data processing operation; and combing unit coupled to selected post-stage latching unit for determining an output for a cumulative data processing operation.
The cumulative data processing operation is one of: integration, and differentiation. Input data are typically parceled into consecutive preselected digit lengths prior to latching. Latching and data processing are generally initiated by clock pulse.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a first embodiment of a data processing apparatus in accordance with the present invention.
FIG. 2 is a flow diagram of a method utilized by a data processing apparatus in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1, numeral 100, is a block diagram of a first embodiment of a data processing apparatus in accordance with the present invention, the apparatus implementing a pipelined look-ahead accumulation format of the present invention. The data processing apparatus, 100, utilizes at least pre-stage latches (102, 104, 106, . . . ) to receive input data, wherein the input data is parceled into consecutive preselected digit lengths (0 to M-1, M to 2M-1, 2M to 3M--1, . . . ). In binary data processing, for example, the digit length selected is typically determined by a number of bits that can be processed in a single clock cycle.
A plurality of first latches (LAT) is coupled in a cascade fashion for data flow from each selected first latch (FIRST LAT, SECOND LAT, THIRD LAT, . . . ;102, 104, 106, . . . ) to further selected pre-stage latches (none, FOURTH LAT, FIFTH LAT; none, 110, 112, 118, . . . ) to data processors (DP) having first outputs (FIRST DP, SEC DP, THIRD DP, . . . ; 108, 120, 128, . . . ) that feedback to a selected pre-stage latch (TWEL LAT, THIRT LAT, FOURTEEN LAT, . . . ;103, 105, 107;, . . . ), that provide second outputs to second latches (SEV LAT, ELEV LAT, . . . ; 116, 126, . . . ) for carry, and that provide desired data flow forward through selected post-stage latches (SIXTH LAT, NINTH LAT, . . . -114 122, . . . ; TENTH LAT, . . . -124, . . . ). In a first cascade, a FIRST LAT (102) is coupled to a FIRST DP (108) that is coupled to a SIXTH LAT (114), the SIXTH LAT (114) being coupled to a NINTH LAT (122), continuing with coupling to further latches as desired. Further, the FIRST DP (108) is coupled to a SEV LAT (116) to provide a carry to a next data processing grouping and feeds back to a pre-stage TWEL LAT (103). Data processors (FIRST DP, SEC DP, THIRD DP, . . . ; 108, 120, 128, . . . ) perform a built-in designated operation, being one of: addition and subtraction.
Third latches (TWEL LAT, THIRT LAT, FOURTEEN LAT, . . . ;103, 105, 107, . . . ) are coupled between inputs and outputs of selected data processing means (FIRST DP, SEC DP, THIRD DP, . . . ; 108, 120, 128, . . . ) for storing selected data processor feedback outputs for utilization in subsequent data processing. At least a first COMBINER (130) is coupled to selected poststage latching means, including an output of a last selected data processor, for determining an output for the predetermined data processing operation. A clock (140) signal/pulse is typically utilized to initiate sequential implementation of latch and data processor functions.
Clearly a number of stages of operation, illustrated as horizontal rows of latches and at least a first data processor (DP) (a first row being latches 102, 114, 122, . . . and data processor 108) is selectable. Also, a number of groupings (102, 108, 114, 122, . . . ; 104, 110, 116, 120, 124, . . . ; 106, 112, 118, 126, 128, . . . ; . . . ) , each grouping data processing a preselected digit length, is selectable by a user, typically based on a user's desired speed of data processing.
The first embodiment incorporates a pipelined look-ahead format of the present invention wherein at least a first carry-ahead latch (SEV LAT, ELEV LAT, . . . ;116, 126, . . . ) is utilized to implement a carry to the at least second data processor of a second stage of operation, thereby facilitating an integration operation. Although binary arithmetic is described in detail below, it will be apparent to one versed in the art that the concept of the present invention may be extended to other number bases.
An operand, A , representable by a number of bits, is input to an apparatus, being the first embodiment in accordance with the present invention. Consecutive M bits of A (IP1 (0 to M-1); IP3 (M to 2M-1); IP5 (2M to 3M-1); . . ) are, where desired, input into a first latch (102, 104, 106, . . . ) of each first stage of operation. The first latch (FIRST LAT, FOURTH LAT, EIGHTH LAT, . . . )(102, 110, 118, . . . ) immediately prior to a data processor (FIRST DP, SEC DP, THIRD DP, . . . )(108, 120, 128, . . . ) also latches in a previous cumulative output of the data processor immediately following (FIRST DP, SEC DP, THIRD DP, . . . )(108, 120, 128, . . . ). Low order bits of both inputs are utilized by the data processor (FIRST DP, SEC DP, THIRD DP, . . .)(108, 120, 128, . . . ) to determine a low-order sum and a carry that is provided to second latches (SEV LAT, ELEV LAT, . . . )(116, 126, . . . ). It is important to note that, although the entire data processing operation has not been completed yet, the operation just described is independently determined, since it in no way depends on higher order bits of previous data processing operations. Higher order bits of the input are stored in first latches (SECOND LAT, THIRD LAT, ...)(104, 106, . . . ) for later use in accordance with the above procedure. The operand input bits are valid at the time when the CLOCK(140) strobes them into a set of first latches (FIRST LAT, SECOND IAT, THIRD LAT, . . . (102, 104, 106, . . . ). Lowest order bits of the operand stored in a first pre-stage latch (FIRST LAT)(102) are applied directly to a first data processor (FIRST DP)(108), typically an M-bit adder, while all higher bits are buffered by a further set of first latches (FOURTH IAT, FIFTH LAT, . . . )(110, 112, . . . ). At the same time, lower bits of a previous cumulative result are stored in a TWEL LAT(103) and presented to the FIRST DP(108). Latches are operated by a clock signal generated by the CLOCK (140), that defines a rate of data processing and updates the operand inputs supplied to the data processing apparatus, 100, as well as to the output.
Simultaneously, operand input bits from the SECOND LAT (104) are strobed into the FOURTH LAT (110), the previous cumulative result from the next-to-lowest order bits from SEC DP, typically an M bit adder(120), are strobed into a THIRT LAT (105), and the carry result from the operation previously performed on the lower order bits by the FIRST DP(108) is strobed into the SEV LAT(116). These data are then presented to the SEC DP(120), typically a second M bit adder, which proceeds with the determination of a next-to-lowest order bits of a next result. The first data processor (FIRST DP)(108) is simultaneously determining low-order bits of a next result. For an embodiment implementing a three grouping set of levels (THIRD LAT, FIFTH LAT, EIGHTH LAT -106, 112, 118, 128 being a last set of latches and data processor implemented), on a third clock cycle, a second data processor (SEC DP)(120) sum output is stored in the TENTH LAT (124), a corresponding result of low-order bits is transferred from the SIXTH LAT (114) to the NINTH LAT (122), and high-order bits are transferred from the FIFTH LAT (112) to the EIGHTH LAT (118). The FOURTEEN LAT (107) also stores a previous result from the third data processor (THIRD DP) (128). A carry result from the SEC DP (120) is stored in the ELEV LAT (126), and the contents of the ELEV LAT (126) and the EIGHTH LAT (118) are latched to the THIRD DP (128). At the next clock cycle, a COMBINER (130) combines, typically by summing, outputs of the THIRD DP (128), as well as outputs of the TENTH and NINTH LAT (122, 124) to obtain a desired accumulated result.
While the above text describes only integration, it will be obvious to one skilled in the art that the concepts described for integration are directly applicable to the problem of differentiation.
FIG. 2, 200, sets forth a flow diagram of a method utilized by a data processing apparatus in accordance with the present invention. The present invention utilizes a method of performing a carry look-ahead cumulative data processing operation. An input value is utilized such that the input value is parceled into consecutive preselected digit lengths comprising a first lowest digit length LD1 and first upper digit length(s) UD(S)(202). The first upper digit length(s)(FIRST UD(S)) and lowest digit length (LD1) of the consecutive preselected digit lengths are latched in parallel in selected pre-stage latches (204). The first lowest digit length LD1 is data processed, typically by addition, to obtain a processed first lowest digit length LD2 and a first carry CB1, and to feed back the processed first lowest digit length to a selected pre-stage latch, respective parallel digit length(s) being latched to provide data flow (206). Latching the processed first lowest digit length LD2, latching the first carry CB1, and latching the upper digit length(s) provides a second lowest digit length LD10 and next respective upper digit length(s) (SECOND UD(S))(208). Respective parallel digit length(s), here LD2, are latched in each step simultaneously to provide data flow (214).
The second lowest digit length LD10 is data processed, typically by addition, to provide a processed second lowest digit length LD11 and a second carry CB2, and to feed back the processed second lowest digit length to a selected pre-stage latch, respective parallel digit length(s) being latched to provide data flow (210). Latching of the processed second lowest digit length LD11, latching the second carry CB2, and latching the second upper digit length(s) provide a third lowest digit length LD100 and third respective upper digit length(s) (THIRD UD(S))(212).
The third lowest digit length LD100 is data processed to provide a processed third lowest digit length LD101 and a third carry CB3, and to feed back the processed third lowest digit length to a selected pre-stage latch, respective parallel digit length(s) being latched to provide data flow (214).
Latching and data processing are continued, implementing respective carry in the fashion described above, for a selected number of repetitions (216). Then latch outputs are combined to obtain a desired output (218).
Clearly, while binary input data format is described above, format is selectable. Also, as set forth for the data processing apparatus, the method of the present invention utilizes clock pulse initiation of data processing and latching.
For example, referring to FIG. 1, assume M=1 and a total number of bits available is N=3; i.e., A and B are 3-bit operands. Thus, the first DP (108) is a 1-bit half-adder, and the second DP (120) and the third DP (128) are 1-bit full adders. Each line for data flow in the FIG. 1 is equivalent then to 1 bit. Operand A presented at each clock cycle (time slice) is represented in the following discussion with its representative letter and the time slice at which presented; i.e., A1 is an operand presented at a first clock cycle, A2 is an operand presented at a second clock cycle, and so on. Due to pipelining, a first result R1=A1 is not available until a third clock cycle, a second result R2=A1+A2 is not available until a fourth clock cycle, and a third result R3=A1+A2+A3 is not available until a fifth clock cycle. Carry out is normally ignored in an integration operation in order to maintain consistency of overflow operation. Individual bits of operands and results are represented by a bit number following the operand or result; therefore, A2(0) is a least significant bit of a second A operand, and R1(2) is a most significant bit of the first result. Note that the carry output of a result is normally ignored for integration. All outputs described represent a stable result at the end of the time slice.
For the purposes of this example, the following values for operands will be used:
A1=2 (binary 010)
A2=3 (binary 011)
A3=5 (binary 101)
Implementation of these operands provides a normal overflow of a result, with an expected sum of 10 (binary 1010) limited to three bits, and thereby overflowing to 2 (binary 010).
The following tables show outputs of latches and adders in each time slice as the above operands are sequentially applied to the apparatus of the present invention. For simplicity, the latches are assumed to be initialized to zero before the first clock cycle, and all operands successive to the third time slice are assumed to be zero. Different stages of the pipeline are staggered for clarity; the time slices are delineated by vertical lines.
______________________________________Time slice: 1 2 3 4 5______________________________________Latch 106 0 0 1 0 0Latch 104 1 1 0 0 0Latch 102 0 1 1 0 0Latch 103 0 0 1 0 0Adder 108 (carry out) 0 0 1 0 0Adder 108 (sum) 0 1 0 0 0Latch 112 0 0 0 1 0Latch 110 0 1 1 0 0Latch 105 0 0 1 0 0Latch 116 0 0 0 1 0Adder 120 (carry out) 0 0 1 0 0Adder 120 (sum) 0 1 0 1 0Latch 114 0 0 1 0 0Latch 118 0 0 0 0 1Latch 107 0 0 0 0 0Latch 126 0 0 0 1 0Adder 128 (carry out) 0 0 0 0 1Adder 128 (sum) 0 0 0 1 0Latch 124 0 0 1 0 1Latch 122 0 0 0 1 0______________________________________
The lower three bits in the table represent a result in descending order of magnitude. Therefore, R1 (seen in time slice 3) is binary 010, or 2, R2 (seen in time slice 4) is binary 101, or 5, and R3 (seen in time slice 5) is binary 010, or 2. These are the results from the given operands.
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An apparatus (100, 200) and method (300, 400) include an improved architecture for data processing that maintains data throughput while maintaining a reasonable circuit complexity. The method utilizes a system of calculating subsets of desired results that are independent of results of subsets not yet calculated, while providing a system of storage for data yet to be used and previously calculated results.
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TECHNICAL FIELD OF THE INVENTION
The present invention relates in general to systems for the generation of electricity through renewable means such as water-driven turbines. More specifically, the present disclosure relates to turbine generator systems that remote-controllably convert nontidal high seas current energy to low cost electricity where the systems are self-propelled and submersible containing current amplifiers and marine life protectors.
BACKGROUND OF THE INVENTION
The cost of power in the United States is one of the most expensive cost of living elements incurred by the consumer. This makes finding less expensive sources of electricity of paramount importance for the continued economic vitality of the country. Depending mainly upon the geographic location and the source of power generation, these costs may vary considerably. This is clear from the following comparative listing of power sources, a five-year forecast of the estimated U.S. average power costs in dollars per kilowatt hour for most regular and renewable sources of energy as prepared by the U.S. Energy Information Agency (EIA) as of 2015:
Geothermal
$.048/kwh
Onshore Wind
.074
Hydro
.083
Conventional Coal
.095
Advanced Nuclear
.095
Biomass
.100
Advanced Turbine, Natural Gas
.113
Solar, Photovoltaic
.125
Offshore Wind
.197
Concentrated Solar Power
.240
The above $/kwh listing represents the EIA's estimated levelized cost of electricity (LCOE) and is a measure of a power source which attempts to compare different methods of electricity generation on a comparable basis. It is an economic assessment of the average total cost to build and operate a power-generating asset over its lifetime divided by the total energy output of the asset over that lifetime. The LCOE can also be regarded as the minimum cost at which electricity must be sold in order to break-even over the lifetime of the project.
By comparison, the LCOE for several versions of this invention was estimated to be in the order of $0.045/kwh, or about the same low cost as geothermal.
Our above LCOE for this invention was computed on the same basis as that of the EIA in that our cost range consisted of the capital to build and to operate the present invention including all maintenance, overhead and interest expenses over the asset lifetime divided by the total energy output of the asset over that lifetime. Our estimates thus indicate that the present invention has the potential of saving the public substantial expenses for future power costs.
It has been well established that renewable energy is a more desirable power source alternative than other fuel means since it is much cleaner than fossil fuel, far safer than nuclear energy and is abundant. Solar, offshore and onshore wind projects require extensive areas for operation, may be environmentally disruptive and are generally expensive and considered by many to be unsightly. Geothermal, onshore wind and inland hydro may also be unsightly and environmentally disruptive but are the least expensive of the alternative energy power sources. However, they are less desirable for investment for generation purposes owing to the general scarcity of their areas for suitable economic operation. Thus marine currents offer attractive potential for a source of power since the cost will generally be lower for certain types, the systems are usually submerged out of sight and the area of suitable ocean current availability is the most extensive available. These factors probably account for the present increase in tidal current programs throughout the world although such programs may be problematic owing to high installation cost and environmental impact. However, at this time there are no known commercially active power generation systems designed for operating in the high seas in non-tidal areas except for this invention.
Excluding offshore wind projects, virtually all renewable ocean power generation systems in use today extract energy from tidal mechanisms that rely on water moving alternatively in two directions where the full generation of power is limited to somewhat less than a full day. Such systems are located at or near shallow edge water areas where environmental conditions may be disrupted and their presence may be unsightly. This is especially true of power generation systems requiring the building of extensive shoreline embankments or levees to form lagoons that temporarily retain and store incoming seawater for release during periods when the tide recedes. The lagoon systems can be unsightly and all are expensive to build because of the often extensive land work needed to build the levees. Such expenses must be passed on as the cost of power to the consumer. Other tidal systems may be comprised of a free standing submerged turbine generators that are mounted on large stands or on buried foundations located in shallow waters where there is a significant danger to marine life and may be a hazard to water sports and other surface activity. Tidal energy is harnessed in a cyclical manner from the incoming and outgoing currents resulting in a discontinuous pattern of electricity generated.
In the past, various patents have addressed the issue of using the hydrodynamic force of water to generate power. For example, U.S. Pat. No. 3,986,787 issued to Mouton and Thompson and published on Oct. 19, 1976, describes a platform upon which is mounted above water an electrical power generator connected by a drive belt to an underwater turbine wheel on a horizontal shaft that is coaxially mounted below the platform within an intake nozzle in a river current. The system is manually transported and anchored to the river bottom to a location where it remains floating at the surface where it may be subject to accident with surface marine traffic; it has no means of amplifying the ocean current speed.
U.S. Pat. No. 4,163,904 issued to Lawrence Skendrovic and published on Aug. 7, 1979, provides for a turbine plant anchored to the sea floor that provides for generating electrical power by means of the flow of coastal water currents. Each turbine plant has a large central opening within which is mounted a large turbine impeller. An electrical generator is mounted within the watertight housing of the plant adjacent to the central opening. The opening of the plant has a large diametrical forward entrance and a large diametrical rearward exit with a substantially central portion of smaller diametrical extent. The impeller of the turbine plant is mounted in the smallest diametrical extent of the opening. The contour of the opening provides for a Venturi effect increasing the efficiency of plant operation. The system is manually transported and anchored to the river bottom but has no means of amplifying the ocean current speed.
U.S. Pat. No. 4,219,303 granted to Mouton and Thompson and published on Aug. 26, 1977, calls for a power plant for the generation of electricity from the flow of water currents that uses turbine wheels within nozzles submerged in the water current, anchored to the bottom of the water course, as for example, the ocean, and self-buoyed to a level well below the water surface. Pairs of counter-rotating turbines are supported by their rims, which bear against friction drive wheels, which in turn drive electrical generators contained in water-tight deep-water machine rooms within the wall of the nozzle. The system is manually transported to the selected site then anchored to the sea bottom where the elevation of the system above the sea floor is manually set; it has no means of amplifying the ocean current speed.
U.S. Pat. No. 4,224,527 received by Jack E. Thompson and published on Sep. 23, 1980, wherein he describes a method of intensifying a relatively slow speed, substantially horizontal flow of a natural fluid, such as a tidal flow, as opposed to a tidal rise, or a river flow, the natural flow being used to turn about a substantially horizontal axis rotary means arranged to act directly on a working fluid, which may be the natural fluid, where the latter is a liquid, or a separate liquid, and force it through a pipe system to a flow intensifier in the form of a constriction anchored to the floor of the body of water. The working liquid is forced through the pipe system without the formation of a head, and can be used to drive means for generating electricity. Flow intensifying apparatus is also described using seawater as the natural fluid and either fresh water or the seawater as the working fluid. Several of the apparatus may be disposed to cause a vortex or maelstrom which then serves to drive the apparatus which must be set manually. It has no means of amplifying the ocean current speed and offers no protection for marine life.
U.S. Pat. No. 4,383,182 granted to Wallace W. Bowley and published on May 10, 1983 is based on energy being produced in a power producing module by means of a turbine energized by ocean currents where a shaft rotationally connecting the turbine to a pump then moves a system fluid that is conveyed from the power producing module to a separate power absorbing module by means of piping; the moving system fluid then drives a turbine in the power absorbing module where a turbine is axially connected to a generator that rotationally produces power. He relates that large quantities of power may be produced in this manner by coupling several such power producing modules to the power absorbing module and thence to a power grid for sales. The system must be transported and positioned manually; it has no means of amplifying the ocean current speed and offers no protection for marine life.
U.S. Pat. No. 7,768,145 received by Hector Fillipus, Alexander Van, Drentham Susman, Kenneth Stewart and Donald Stewart, published on Aug. 3, 2010, relates to an underwater turbine unit housed in a cylindrical body and connected rotationally to a electrical power generator mounted on the seafloor in shallow water to capture energy from reversing tidal ocean currents. A multiplicity of such turbine generators are connected to a power center for transfer by cable to shore. The system must be transported and positioned manually; it has no means of amplifying the ocean current speed and offers no protection for marine life.
US WO2015142737 A1 credited to James G. P. Dehlsen and published on Sep. 24, 2015, provides for a floating tower frame for a plurality of connected turbine systems placed in ocean currents for the purpose of generating electrical power or high pressure seawater for reverse osmosis or fresh water production from steady (gyre) or tidal currents. The subsea turbines are mounted near the base of a plurality of floating towers held in parallel between a horizontal truss structure above water and a horizontal wing at the base of the towers, below the surface. Part of the structure is above water and subject to the risk of an accident with marine traffic. Further, the system must be transported and positioned manually; it has no means of amplifying the ocean current speed and offers no protection for marine life.
U.S. Pat. No. 6,091,161 registered to James G. P. Dehlsen, James B. Dehlsen and Geoffrey F. Deane was published on Jul. 18, 2000. This art form may be described as two tethered, submerged, ocean current-driven turbines with counter-rotating, variable pitch blades. The two turbines are axially connected to separate electric generators and are joined by a water-wing like structure having a canard-like device located centrally on the wing to assist in controlling the depth of the system. This power-generating device may be set to a predetermined maximum depth and a predetermined minimum depth in addition to the selective setting of a sensing depth involving an ascend command or a descend command where the operating depth of the system is midway between the predetermined maximum depth and the predetermined minimum depth. Further, the system must be transported and positioned manually; it has no means of amplifying the ocean current speed and offers no protection for marine life.
U.S. Pat. No. 8,272,831 issued to Barry Johnston and published Sep. 25, 2012, is comprised of an apparatus for the generation of power from sea currents that includes an elongate, generally circular in cross section, free floating tubular buoyancy vessel having affixed to its underside on a mounting means, rotatable rotor blades. The rotor blades are connected to a power generating means whereby the movement of sea water currents across the rotor blades, drives them so as to generate power. The apparatus is tethered to the sea bottom or other fixed point where power is exported by cable attached to the tether line. The system must be transported and positioned manually; it has no means of amplifying the ocean current speed and offers no protection for marine life.
SUMMARY OF THE INVENTION
Except for those prior art devices that are offshore wind driven power generation systems, prior hydrodynamic art systems provide only for tidal operation but not for nontidal, high seas power generation. Those offshore wind-driven power generation systems that operate on the surface of high seas require substantial room, appear unsightly, result in high cost power and may be a hazard to marine water fowl and to surface traffic. As noted earlier, the remaining tidal and other onshore power generation systems also have serious unsightly appearance, environmental issues and safety problems.
The prior art power generator systems are essentially all burdened with a high cost to produce electricity thus resulting in an excessive charge of power to the consumer. For example, the country of Denmark currently relies on wind turbines for 42% of their electricity. Danish consumers now pay the highest electricity charges in Europe owing to expensive offshore and onshore wind-generated power. Reliability has also become a serious problem since on some days the Danish wind farms produce more electricity than required while on other days the turbines are still and power from expensive storage batteries must be used. Germany and Great Britain are now having similar problems and are scaling back plans for wind energy. In addition to high capital and operating costs, the hazard to wildlife and the unsightly appearance are also contributing factors to the unpopularity of wind farms.
Wind energy is not an isolated case since tidal current power generators that are planned, being installed or are operating in shoreline areas of Great Britain and northwestern Europe will produce power at high costs with various levels of environmental difficulties. As noted herein, certain extreme cases of tidal energy generation require a man-made levee or berm in which to temporarily trap tidal sea water for operation. These types of tidal energy generators could have a serious impact on the environment while their construction costs must be paid by the end user customer in the form of higher electric costs.
Relative to the prior art, there remains a need for a renewable energy generating system that is submersible and self positioning that can operate safely in non-tidal, deep water areas and safely below marine surface traffic in a manner that would not be unsightly or harm the marine environment. The system must be capable of economically generating power from high and lower speed currents in order to be applicable in worldwide bodies of water. But the system must also be capable of moving to new locations to capture the energy of fast, meandering ocean currents. Such a system must be capable of producing large amounts of continuous clean power at a cost to the consumer below that of fossil fuel systems such as natural gas and within required environmental parameters. For optimum operations the system must be continuously controlled at all times by either live operators or by programmed software within defined limits and monitored onshore by live operators. The present invention embodies these features.
One of the major issues in converting non-tidal sea currents to electric power is the relatively slow speed of most ocean currents that cover very large areas as opposed to the generally much faster tidal currents that are usually located in remote areas of smaller areal size. To increase current speeds in all ocean current areas, the proposed invention provides for a cone-like current amplifier where sea currents are accelerated to much higher levels based on the Bernoulli Principle as demonstrated in this document. This concept was formulated by Daniel Bernoulli in 1738 and has been utilized extensively since that time in the fluid flow analyses of air, water and other fluids. The geometric form of the Bernoulli Principle as applied for the proposed invention is a truncated cone with water entering the large end and exiting at a much higher speed at the small end as demonstrated herein. This is a valuable concept since seawater currents may be accelerated using a current amplifier by a factor of from 7 to over 9, depending upon the turbine design, ratio of cone intake to outlet diameters and other physical factors. The present invention utilizes this principle.
Another of the major issues in converting non-tidal sea currents to power is maintaining the location of the generating system within the area of maximum current speeds for greatest turbine rotation and power generation. Studies have demonstrated the meandering aspect of currents in many regions such as the Florida Straits where the high speeds of “jet stream” shallower currents are some of the highest velocities in the world but are capable of changing their location over time as discovered by oceanic field studies. Oceanographic studies reveal that these currents have their highest speeds closer to the surface. Today, these high speed meandering surface currents may be continuously monitored from shore to distant offshore areas by high frequency radar. Onshore operators of the proposed invention will utilize this type of radar in selecting certain areas of maximum current velocity and will then move the invention remotely by self-propelled means to that selected area, remotely anchor the system and then produce power at a lower cost in the higher speed currents. Such a power generating system would be of great benefit to developing coastal and other similar countries having substantial power needs. The present invention utilizes a self-propelled means and relies on high frequency radar for detection of high speed current areas.
Aspects of the present invention provide for the generation of electric power from ocean currents. More specifically, aspects of the present invention provide for power generation from generally unidirectional high speed shallower non-tidal currents in the high seas. A system based on the present invention may be deployed in any body of water having moving currents.
Example Operation
The operation of the present invention may be best examined through the description of an example of a typical move of the invention to a new location. The setting for a new location would be in the Florida Straits, or similar areas worldwide, where the surface current speeds of the south-to-north traveling currents are high and may exceed five knots in shallower depths at some distance eastward from shore. It is important to note that the fast moving currents generally take the form of a water “jet stream” within the ocean and are often of a meandering nature. The water depths in these areas are about 400 meters. The invention would be positioned offshore near the deep water end of a previously laid and buried power trunk line that would extend from a onshore power grid location and eastward at a right angle to a distance of least 16 kilometers from the Florida shoreline. The power trunk line will have a plurality of connecting points along its length that extend vertically a short distance above the ocean floor. Any single connecting point on the power trunk line may be coupled to the branch power transmission line, referred to herein as the power and utility line that is contained and stored reelably within the invention in order to transfer generated electricity to the trunk line and into to the onshore power grid location. The connections may be made with remotely operated vehicles or ROV's that are used extensively in the offshore oil industry for such mechanical operations.
Basically the embodiments of the present disclosure consist of a large truncated cone-like submerged device that is remotely collapsible in an umbrella-like fashion and is referred to as a current amplifier. It is constructed of a rigid metal frame covered by flexible urethane sheeting or similar material, the large end or front of which is the ocean current intake and is joined to, and covered by a metal gridwork called a marine life protector that is also collapsible in an umbrella-like fashion simultaneously with the current amplifier. The small end of the current amplifier is coupled to a turbine that is rotationally activated by substantially accelerated sea currents received from the current amplifier and is rotationally connected to a power generator. The rotationally activated power generator then transmits electricity to a reelable power and utility line contained within the body of the invention. The power and utility line is further extended downward to the sea floor where it is coupled to the power trunk line as the means of transmitting electricity to the onshore power grid location. Because of the meandering nature of the faster currents it would be necessary to move the invention on occasion to maintain a position within these currents by means of azimuth thrusters affixed to the invention that provide mobility in any lateral direction. In this embodiment of the invention the power generation system would be transported in an east-west direction along the buried trunk line line and perpendicular to the direction of current travel. Ballast tanks would be utilized for vertical positioning of the invention. The invention would be under the monitoring and operative command of the onshore control center at all times.
The first step in the movement to a new location is the selection by the onshore control center of that offshore area having the greatest ocean surface current speeds as these areas contain the highest energy potential for conversion to power. The invention will be positioned at a depth of about 60 meters and below the keels of large vessels for power generation. Thus a review of surface currents by the onshore control center will be undertaken to locate high current speed areas. Commercial shore entities provide detailed information on the movement of surface currents based on readings from high frequency radar (HFR) installations located onshore near tidal zones. The HFR imagery process is referred to as ionospheric radar or over-the-horizon-radar and is used extensively for a number of offshore applications where large surface areas of up to 200 kilometers from shore may be surveyed. With the use of HFR and satellite imagery, the desired location area of highest current velocities is selected by the onshore control center for placement of the invention as guided by global positing systems or GPS.
The system control memory of the present invention is then supplied with the desired depth and GPS coordinates of the target location area as provided by the onshore control center. The invention begins its journey to the new location while remotely submerged at a depth of about 60 meters and in a transit mode with the current amplifier and marine life protector and all other withdrawable appendages remotely retracted for maximum streamlining and minimum resistance to movement. The turbine blades are remotely locked stationery and neutrally positioned for minimum resistance to forward movement. A plurality of battery-powered, remote controlled azimuth thrusters that propel the device in any lateral direction serve as the means for managing the lateral transit of the invention while ballast tank control serves as the means of vertically positioning the invention. An internal supply of power in the form of high capacity lithium ion batteries or other similar battery forms may be the means of power for the electrically driven azimuth thrusters and ballast water pumps while ballast air may be supplied by high pressure storage bottles. A snorkel-like device may be remotely deployed that may serve as an alternate supply of air and radio communication with the onshore control center in addition to surveillance of surface conditions with a video camera. The onshore control center is in operative command at all times during both transit and while anchored. The invention can also be remotely surfaced using less battery power while in transit for longer travel distances.
Upon arrival at the intended location, the depth to the ocean floor is remotely measured by sonar through the onshore control center followed by the remote setting of the anchors in a pre-selected pattern. If the power and utility line of the invention remains connected to the power trunk line during shorter distance travel to the new location then, following anchoring, the current amplifier and marine life protector are remotely deployed and extended in an umbrella-like fashion by means of an internal mechanical device referred to as a retraction unit where the invention will resemble a large truncated cone with ocean currents entering the large end. The turbine blades are remotely unlocked and positioned for rotating operations. The systems are checked and power generation begins. If the power and utility line of the invention is disconnected from the power trunk line for longer distance travel to the new location then, upon arrival at the new location the power and utility line of the invention is reelably and remotely coupled to a connecting point on the power trunk line by a ROV of the type commonly used in the offshore oil industry for similar remote mechanical operations, systems are checked and power generation begins. The power and utility line is stored reelably in the body of the invention and may be completely retracted for long transit conditions or totally deployed for short transit conditions, depending upon the circumstances.
One general embodiment of the present disclosure is one or more power generation systems for the production of electricity from generally unidirectional currents in a body of water. The system will operate submerged in the body of water and may include: a remote control system connecting the power generation system by fiber optic means or other suitable type of conveyance of operating performance information to onshore management that will then control all operations of the power generation system by the same fiber optic or other means; a truncated cone-shaped current amplifier receives ocean currents at its large end and passes said ocean currents at the small end at a much higher speed to an axially connected cylindrically housed turbine caused to rotate by said currents that is rotationally coupled to a power producing generator further connected by a power transmission cable to an onshore power delivery point; a means of marine transportation for self mobility of the power generation system through a plurality of hydraulic thrusters affixed to the power generation system where said thrusters expel high pressure water in any horizontal direction that may cause horizontal movement to a desired location; a means of vertical control of the power generation system in the form of ballast tanks that may contain various amounts of seawater where said tanks are in hydraulic communication with water pumps; an anchoring means to tether the power generation system so as to maintain it in a desired fixed position; a covering gridwork configured to encircle and cover the large end of the current amplifier so as to protect marine wildlife and prevent other objects from entering the turbine; a motor driven retraction mechanism in operative connection with said current amplifier and marine life protector wherein said mechanism is configured to horizontally retract the joint current amplifier and the marine life protector in an umbrella-like fashion thereby forming a streamlined body to permit ease of movement of the power generation system to different areal locations; following the selection of a specific site and anchoring of the power generating system said retraction mechanism may also open the combined current amplifier and marine life protector in an umbrella-like manner for maximum amplifier image for the purpose of maximizing power generation while protecting marine life; provide the supply of air for buoyancy control when submerged through a flexible, retrievable snorkel-like tubular air conveyance device positioned vertically and in operative communication with said air compressors and the surface for ballast air supply when submerged; an auxiliary communication line affixed lengthwise to said tubular air conveyance device for the purpose of sending and receiving messages when submerged and when in transit; and a video camera whose wiring is affixed lengthwise to said tubular air conveyance device for the purpose of monitoring surface marine traffic when submerged. During transit to different areal locations the power production cable may be reelably retrieved into the power generation system and reconnected following anchoring of the power generation system.
Other possible embodiments of the present disclosure include a self-propelled, remote controlled, submerged power generation system comprising twin buoyancy pods, each flanking and affixed to the pod of a single ocean current powered turbine system in operative communication with onshore management for the purpose of converting renewable hydrodynamic energy from steady-state, generally unidirectional high sea ocean currents to electricity. Said currents may be non-tidal and of a meandering nature. The system comprises: a current amplifier means comprised of a cone-like structure consisting of flexible material held by a rigid framework receiving ocean currents at the larger end coupled at the smaller end to a turbine to cause ocean currents to be conically passed through said amplifier to substantially increase the velocity of the exiting current that is then received by the turbine that is joined rotationally to a generator to create an electric current that is transmitted by power cable connecting the generator to onshore commercial sales; a fiber optic or similar means of communication cable joined lengthwise to said power cable in a continuous manner to receive from the onshore control location such signals as to move the power generation system to a specific location through a self-contained means, then to adjust the vertical position of the system through a self-contained buoyancy means to a specific operating depth below said surface and then to set a plurality of anchors through a self-contained winching means to maintain the system at a specific stationary operating location and depth for power generation operations where said anchors are affixed to the ends of the twin buoyancy pods whose flotation means may be separately controlled to assist in offsetting the effects of torque caused by the rotating turbine.
DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying Drawings in which FIGS. 1 through 20 show various aspects for a Self-positioning Robotic Subsea Power Generation System made according to the present invention, as set forth below:
FIG. 1 . is a schematic diagram of a submerged subsea power generation system, showing a trunk line on the ocean floor which connects the subsea power generating system to onshore power grid facilities;
FIG. 2 is a left side elevation view of the submerged and retracted power generating system in accordance with the embodiments of the invention and illustrating the retracted form of the invention during transportation and prior to power generation;
FIG. 3 is a top view of the submerged and retracted power generating system in accordance with the embodiments of the invention and illustrating the retracted form of the invention during transportation and prior to power generation;
FIG. 4 is a perspective view of the submerged, anchored and deployed power generating system in accordance with the embodiments of the invention and illustrating the form of the invention during power generation;
FIG. 5 is a left side view of the submerged, anchored and deployed power generating system in accordance with the embodiments of the invention and illustrating the form of the invention during power generation;
FIG. 6 is a top plan view of the submerged, anchored and deployed power generating system in accordance with the embodiments of the invention during power generation and illustrating the line of cross section as presented in FIG. 7 ;
FIG. 7 is a cross sectional view of the submerged, anchored and deployed power generating system in accordance with the embodiments of the invention taken from the cross section depicted in FIG. 6 ;
FIG. 8 is a rear view of the submerged, anchored and deployed power generating system in accordance with the embodiments of the invention and illustrating the form of the invention during power generation;
FIG. 9 is a front view of the submerged, anchored and deployed power generating system in accordance with the embodiments of the invention and illustrating the form of the invention during power generation;
FIG. 10 is a control diagram illustrating a system in accordance with embodiments of the invention;
FIG. 11 is a side elevation view of one of the power generating units and has hidden lines which show operation of the retraction unit for the marine life protector;
FIG. 12 and FIG. 13 are partial cutaway drawings of an air supply snorkel which is located near the rear topside of the power generating units, with FIG. 12 showing the snorkel in a retracted position and FIG. 13 showing the snorkel in an extended, or deployed, position;
FIG. 14 and FIG. 15 are partial cutaway drawings of the emergency flotation system;
FIG. 16 is a cutaway drawing for the upper stabilizer-rudder, located near the rear of one of two power generators;
FIG. 17 and FIG. 18 are partial, cutaway views of one of the azimuth thrusters for the power generating system; and
FIG. 19 and FIG. 20 are partial cutaway drawings of an anchor cable reel for selectively spooling an anchor cable to secure the power generating units in selected positions within ocean currents.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the Figures, the principles of the invention are explained by describing in detail specific example embodiments of devices, systems and methods for generating electrical power in a body of moving water. Those skilled in the art will understand, however, that the invention may be embodied as many other devices, systems, and methods. Many modifications and variations will be apparent to those of ordinary skill in the art. Embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. The scope of the invention is not intended to be limited by the details of exemplary embodiments described herein. The scope of the invention should be determined through study of the appended claims.
Aspects of the present invention are described below with reference to drawings and flowchart illustrations of methods according to embodiments of the invention. Specific design details have been provided for illustration, but should not be considered limiting. Readers of skill in the art will recognize that many variations of power generation systems may be implemented consistent with the scope of the invention as described by the appended claims.
Generally, aspects of the disclosure concern the generation of electricity by a power generation system in high seas, lagoons, lakes, rivers, reservoirs and other bodies of moving water. Aspects of the present disclosure are unique in that they provide a robotic system that is self-positioning, submersible, offers a current amplification system, marine life protection and continuous monitoring. This power generation system is mobile through the use of electrically-powered water propulsion thrusters located in the stern. This self-propelled feature allows the power generation system to be moved to maintain a desired position within fast moving meandering ocean currents such as those of the Florida Straits. The system also has a retractable aspect that allows the current amplification system and the marine life protection device to be remotely collapsed in an umbrella-like manner for transit. This power generation system has rudder and elevator controls on the stabilizers should secondary horizontal and vertical control be required; normally primary control for these directions may be provided by ballast tank control for vertical movement and azimuth thruster control for horizontal movement either while anchored or in transit. The reelable anchoring system may also offer a means of directional control while stationed at a power generation site since each of the anchor cables may be separately reeled up or down. Following transit to a new location the power generation system may then be anchored by remote control. The power generation system is equipped with an emergency flotation system in the event of an accidental loss of buoyancy.
FIG. 1 . is a schematic diagram of power generation system 1 connected to a trunk line 90 which connects the power generation system 1 to onshore power grid facilities 92 and then to customer distribution. The trunk line 90 has a plurality of connecting points 91 spaced apart at regular intervals, in this view showing four of the connection points 91 . The power generation system 1 can be connected at various specific connection points 91 , thus operating in different regions in the sea where the power generation system 1 may be placed according to the location for optimal sea currents for generating electric power. The power and utility line 4 connects between the power generation system 1 and the connection point 91 of the trunk line 90 . The power generation system 1 is preferably self-propelled for moving to a desired location with swift portions of the ocean currents, controlled either by onboard electronics or controlled manually by an operator for moving to a desired location. Anchors 20 are provided for securing to the seabed floor, with anchor cables 11 connecting between the anchors 20 and the power generation system 1 . As discussed below in reference to FIGS. 19 and 20 , anchor cable reels 45 may be used for fine tuning the position of the power generation system 1 within the swifter portions of the ocean currents.
FIG. 2 is an elevation view of the left side of the power generation system 1 in a submerged position where the invention is readied for transit in accordance with embodiments of the present disclosure. As will be apparent in FIG. 3 , the side view of FIG. 2 does not reveal the adjacent twin power generating system, the twin of which is located directly behind this view. The current amplifier 3 is retracted in an umbrella-like fashion in order to streamline the exterior of power generation system 1 for minimizing resistance during transit. The turbine 12 with pitch controlled blades (not shown here) is coupled with the current amplifier 3 where it receives high velocity ocean currents when anchored and is further coupled rotationally with power generator 2 . Ballast tanks 6 and 9 provide buoyancy and pitch control for the power generation system 1 while in transit, and are automatically governed by system 16 control 29 (not shown here) contained in ballast tank 9 and monitored by the onshore control center. During transit azimuth thruster 17 causes movement in any 360 degree horizontal direction and is the primary lateral control mechanism of power generation system 1 while in transit. The upper stabilizer-rudder 8 , the lower stabilizer-rudder 13 and the stabilizer-elevator 10 may provide attitude control of the power generation system 1 generally while anchored but may also provide control while in transit. The upper stabilizer-rudder 8 and lower stabilizer-rudder 13 acting independently or together may control the roll or yaw of the system during movement. Similarly, the stabilizer elevator 10 may control the pitch of the power generation system 1 . The action imposed on the current amplifier hinge mechanism 14 and the turbine hinge mechanism 15 allow for the deployment or retraction of the current amplifier 3 and the marine life protector 5 (not shown here) for the initiation of power generation or for transit, respectively. Anchors 20 are retracted as shown during transit.
FIG. 3 is a top, plan view of the power generation system 1 in a submerged position where the invention is readied for transit. The current amplifier 3 is retracted in an umbrella-like fashion over the inwardly retracted marine life protector 5 (not visible in this drawing but appears in the remaining illustrations) in order to streamline the exterior of power generation system 1 thus minimizing resistance during transit. The turbine 12 with pitch controlled blades (not shown here) is coupled with the current amplifier 3 where it receives high velocity ocean currents when anchored and is further coupled rotationally with power generator 2 . Ballast tanks 6 and 9 provide buoyancy and pitch control for the power generation system 1 while in transit, and are automatically controlled by a system control 29 contained in ballast tank 9 and monitored by onshore management. During transit azimuth thruster 17 causes movement in any 360 degree horizontal direction and is the primary lateral control mechanism of power generation system 1 while in transit. The upper stabilizer-rudder 8 , the lower stabilizer-rudder 13 (not shown here) and the stabilizer-elevator 10 may provide attitude control of the power generation system 1 generally while anchored but may also provide control while in transit. The action imposed on the current amplifier hinge mechanism 14 and the turbine hinge mechanism 15 allow for the deployment or retraction of the current amplifier 3 and the marine life protector 5 (not shown here) for the initiation of power generation or for transit, respectively. Communication means may be sent and received during transit by tube-like snorkel 16 (not deployed here) which also serves as a visual means for surface cameras and as a means of conveying air from the surface to the power generation system 1 for ballast control. The emergency flotation system 18 may be activated automatically or manually by shore management. Anchors 20 (not shown here) are retracted during transit.
FIG. 4 is a perspective view of power generation system 1 in a submerged position and anchored for power generation in accordance with embodiments of the present disclosure. This view shows that power generation system 1 is comprised of two interconnected cone-like systems containing counter rotating turbines with adjustable blades (not shown here) that are moved rotationally by ocean currents. The purpose of the counter rotating movement is to eliminate torque that may be caused by rotating equipment. The four anchor cable 11 systems for this example are remotely set in a pattern upon arrival at the offshore site to maintain the power generation system 1 in a fixed and specified position. Only the upper part of the anchor cable 11 systems are shown here. The current amplifier 3 and marine life protector 5 are opened in umbrella-like fashion as seen here to capture large volumes of sea currents for power generation. Ocean currents first enter power generation system 1 around bow ballast tank 6 , marine life protector hinge mechanism 19 and retraction unit 7 , and through the marine life protector 5 and current amplifier hinge mechanism 14 and into the current amplifier 3 where the currents are accelerated to a much higher level as they enter through the turbine hinge mechanism 15 , then through the turbine 12 where the hydraulic force of the ocean currents causes rotational movement of the axially connected power generator 2 such that the generated electricity is transported to shore for commercial use by the reelable power and utility line 4 . The ocean currents continue movement over flow control surfaces as seen by stabilizer-elevator 10 , upper stabilizer rudder 8 and azimuth thruster 17 .
All operations for the equipment shown in FIG. 4 are monitored through fiber optic or similar communication means by system control 29 (not shown here) and contained in power and utility line 4 where electronic operating commands are also sent from the onshore control center to power generation system 1 ; emergency power may also be transmitted from shore by means of power and utility line 4 . Said communication means may alternatively be sent and received by radio means either while anchored or during transit through snorkel 16 , a vertical tubular device which also serves as a means of conveying air from the surface to the power generation system 1 as required for ballast control either while anchored or during transit. Snorkel 16 may also contain a video camera to monitor surface activities. Air for ballast control purposes may also be provided by auxiliary compressed air bottles mounted within the ballast tank-utilities 9 housing (not shown here) where such control mechanisms are in active communication with shore management.
FIG. 5 is a view of the left side of the power generation system 1 in a submerged position where the deployed invention is held stationary by a plurality of anchor cable 11 and readied for power generation in accordance with embodiments of the present disclosure. This side view does not reveal the adjacent twin power generating system 18 that is directly behind this view. The current amplifier 3 is comprised of a metallic frame covered with high-strength, flexible polyurethane material for this example and is extended umbrella-like and coupled at the current amplifier hinge mechanism 14 to the marine life protector 5 which is comprised of a metallic grid-like guard extending over the intake of the current amplifier 3 in order to prevent sea life and other objects from passing into the turbine 12 . The retraction unit 7 telescopically moves horizontally inward or outward thereby activating the coupled current amplifier hinge mechanism 14 , the turbine hinge mechanism 15 and the marine life protector hinge mechanism 19 to be moved so as to mechanically deploy or retract the current amplifier 3 and the marine life protector 5 . The turbine 12 receives high velocity ocean currents from the current amplifier 3 and is coupled rotationally with power generator 2 . The power generated is then transmitted to onshore commercial markets through the reelable power and utility line 4 that carries electricity from power generation system 1 in addition to transmitting monitoring information to the onshore control center through system control 29 (not shown) contained in ballast tank-utilities 9 . Power and utility line 4 also transmits operating commands from the onshore control center to system control 29 (not shown).
Ballast tanks 6 and 9 provide buoyancy and pitch control, and are automatically governed by the system control 29 (not shown) contained in ballast tank 9 and monitored by onshore control center. In this version there are four anchor cable 11 systems that may be withdrawn for transit or may be lowered and set to retain the power generation system 1 in a specified location and these anchor lines are located at the bow and stern ends of the power generator 2 housings. Azimuth thruster 17 causes movement in any 360 degree horizontal direction and is the primary control mechanism of power generation system 1 and is generally employed while in transit where it is supplied power by high capacity batteries. The upper stabilizer-rudder 8 , the lower stabilizer-rudder 13 , and the stabilizer-elevator 10 may provide attitude control of the power generation system 1 while anchored or during transit. The upper stabilizer-rudder 8 and lower stabilizer-rudder 13 acting independently or together may control the roll or yaw of the system. Similarly, the stabilizer-elevator 10 may control the pitch of the power generation system 1 . The control center commands are imposed through the system control 29 (not shown here) contained in ballast tank 9 on the current amplifier hinge mechanism 14 , the turbine hinge mechanism 15 and the marine life protector hinge mechanism 19 allow for the deployment or retraction of the current amplifier 3 and the marine life protector 5 for the initiation of power generation or for transit.
FIG. 6 is a top, plan view of the power generation system 1 located in a submerged position and readied for power generation. A cross section 7 is noted on this drawing that is presented in the following FIG. 7 . FIG. 6 shows that power generation system 1 is comprised of two interconnected cone-like systems containing counter rotating turbine 12 units with adjustable blades (not shown here) that are activated rotationally by ocean currents. The purpose of the two counter rotating turbine 12 units is to eliminate torque that may be caused by rotating equipment. The four anchor cable 11 systems appearing in this version are remotely set upon arrival at the offshore site to maintain the power generation system 1 in a fixed and specified location and depth. The current amplifier 3 and marine life protector 5 are then deployed as seen here to initiate power generation. Ocean currents first enter power generation system 1 around bow ballast tank 6 , marine life protector hinge mechanism 19 and retraction unit 7 , and through the marine life protector 5 and current amplifier hinge mechanism 14 and into the current amplifier 3 where the currents are accelerated to a much higher level as they enter through the turbine hinge mechanism 15 , then through the turbine 12 where the hydraulic force of the ocean currents causes rotational movement of the axially connected power generator 2 such that the generated electricity is transported to shore for commercial use by the reelable power and utility line 4 . The ocean currents continue movement over flow control surfaces as seen by stabilizer-elevator 10 , upper stabilizer rudder 8 and azimuth thruster 17 .
In FIG. 6 all operations are monitored through fiber optic communication means of system control 29 contained in power and utility line 4 where electronic operating commands are also sent from the onshore control center to power generation system 1 ; emergency power may also be transmitted from shore in power and utility line 4 . Said communication means may alternatively be sent and received by tube-like snorkel 16 (not deployed here) which also serves as a visual means for surface cameras and a means of conveying air from the surface to the power generation system 1 for ballast control. Air for ballast control purposes may also be provided by auxiliary compressed air bottles mounted within the ballast tank-utilities 9 housing where such control mechanisms are in active communication with onshore control center. The emergency flotation system 18 may be activated automatically or manually by shore management.
FIG. 7 is a sectional view of the power generation system 1 , taken along section line 7 - 7 of FIG. 6 which is drawn through the primary area of power generation system. Marine current hydraulic forces acting on the blades of turbine 12 cause its rotational movement where such movement is transmitted axially to the coupled power generator 2 (not shown here, but is located directly behind turbine 12 ) and such power as generated is then combined from both power generator 2 systems (not shown) in ballast tank-utilities 9 where the power is then transmitted to shore for commercial use through reelable power and utility line 4 extending from the bottom of ballast tank-utilities 9 (not shown here). The pitch of the turbine 12 blades is adjustable during rotation for maximum generating efficiency or for transit purposes. In this case, a four-bladed device housed within turbine 12 with a wide blade surface is employed but the turbine could be comprised of a plurality of blades and of various blade designs. The upper stabilizer-rudder 8 , the lower stabilizer-rudder 13 and the stabilizer-elevator 10 may provide attitude control of the power generation system 1 while anchored or in transit. However, the anchor cable 11 system shown for this case may be the primary source of system control under certain conditions while anchored since the four anchor cable 11 system lines extending from the power generator 2 housings (not shown here but are located directly behind turbine 12 ) may be remotely and independently adjusted reelably inward or outward from the housings for attitude control. If required, additional attitude control may also be provided by azimuth thruster 17 . Emergency flotation system 18 is mounted on the top side of ballast tank-utilities 9 .
FIG. 8 is a rear view of the power generation system 1 , showing the configuration of the twin power units. The rear side of the current amplifier 3 is shown for both of the generators 2 which are comprised of a heavy, foldable polyurethane or other suitable sheet material that is held in a circular fashion by retractable metallic ribbing. The lowermost portion of the electrically-powered azimuth thruster 17 unit is mounted in a similar vertical position at the bottom of turbine 12 and is used primarily to transport the power generation system 1 to selected locations for optimum power production. Said azimuth thruster 17 may also be used for attitude control while the system is anchored. Attitude control may also be done by means of reelably and independently adjusting the anchor cable 11 lengths where such cables are stored on remote controlled drums contained in the power generator 2 housings as shown. As noted above, attitude control may also be exercised through the remote-controlled movement of the upper stabilizer-rudder 8 , the lower stabilizer-rudder 13 and the stabilizer-elevator 10 while anchored. Emergency flotation system 18 and snorkel 16 are mounted on the top side of the ballast tank-utilities 9 housing while the power and utility line 4 is reeled from the lower side of the housing where power is transmitted to an onshore delivery point for commercial power delivery.
FIG. 9 is a front view of the twin power units of power generation system 1 . Offshore ocean currents flow around bow ballast tank 6 , current amplifier hinge mechanism 14 and marine life protector 5 , then into current amplifier 3 where the currents are significantly accelerated as they pass into turbine 12 that is in operative coupled connection with power generator 2 (not shown here) such that the power generated is combined in ballast tank-utilities 9 where such power is then exported to shore for commercial delivery by reelable power and utility line 4 . Two of the four anchor 11 systems are visible in this view as well as a portion of azimuth thruster 17 .
FIG. 10 is a control system block diagram of power generation system 1 in accordance with embodiments of the present disclosure. The generation system control 29 includes a monitoring system 32 comprising a programmed logic circuit 31 and a plurality of sensors 30 positioned in critical areas of power generation system 1 for transmitting operating conditions to, and receiving commands from, the onshore control center. Sensors 30 detect conditions at and around power generation system 1 and are operatively coupled to the programmed logic circuit 31 . The sensors 30 deliver information to the programmed logic circuit 31 indicative of the operating state of power generation system 1 . The operating state may include either nominal operating conditions or transportation conditions. For example, sensor 30 may transmit signals reflecting that a reduction in ocean current speed has occurred at the anchored position due to meandering current conditions. This information may be transmitted by sensor 30 as analog or digital signals utilizing parallel or serial transfer, and may be sent as data packets. Said data may be acted upon automatically by the program logic circuit 31 or manually by onshore management through monitoring system 32 thus causing power generation system 1 to be activated to transportation conditions through system controller 33 where the generation system is remotely transported to a newly selected location through the actions of the retraction unit 7 , power generator 2 , power and utility line 4 , anchor cable 11 , turbine 12 , snorkel 16 , motion control/navigation system 35 , ballast system 36 and camera monitoring system 37 . The signals may be implemented in any manner as will occur to one of skill in the art.
The program logic circuit 31 further includes a memory (not shown) storing a data structure associating received signal values with an operating condition value. The programmed logic circuit 31 includes a memory access circuit (not shown) operatively coupled to the memory configured to access the data structure and return the operating condition value associated with the operating state. The monitoring system 32 may transmit the operating condition data to system controller 33 .
A system controller 33 of the control system 34 may receive operating condition values from monitoring system 32 . The system controller 33 may be activated to send signals to components of the ballast system 36 , such as, for example, the pumping system contained in ballast tank-utilities 9 (not shown), to employ the ballast system 36 to move to a revised operating depth when conditions necessitate. Such a revision could further activate the system controller 33 to send signals to power generator 2 , power and utility line 4 , anchor cable 11 , turbine 12 , snorkel 16 , motion control/navigation system 35 and camera monitoring system 37 . In the event of transport of power generation system 1 to an alternate location the system controller 33 could further activate retraction unit 7 in addition to the above systems. Should it be necessary, emergency flotation system 18 may be activated automatically or manually through system controller 33 .
Memory may be embedded in programmed logic circuit 31 in whole or in part, or may be a separate element operatively coupled to programmed logic circuit 31 . Memory may include any forms of volatile random access memory (‘RAM’) and some form or forms of non-volatile computer memory such as a hard disk drive, an optical disk drive, or an electrically erasable programmable read-only memory space (also known as ‘EEPROM’ or ‘Flash’ memory), or other forms of random access memory (‘RAM’).
FIG. 11 is a side elevation view of one of the power generation system 1 and has hidden lines which show operation of the retraction unit 7 for the marine life protector 5 . Various positions for the marine life protector are shown, in which Position 1 is fully deployed, Position 2 is intermediate, and Position 3 is fully retracted. The basal point connection of the marine life protector 5 is attached to the marine life protector hinge mechanism 19 and the marine life protector 5 moves down the side of the hinge mechanism 19 between Position 1 and Position 2 during retraction.
FIG. 12 and FIG. 13 are partial cutaway drawings of the snorkel 16 which is located near the rear topside of the ballast tank-utilities 9 . FIG. 12 shows the snorkel 16 in a retracted position and FIG. 13 shows the snorkel 16 in an extended, deployed position. A housing 51 has a hatch 52 from which the snorkel 16 is deployed by means of spooling a snorkel line 55 from a snorkel reel 53 , powered by an electric motor 54 . The snorkel 16 has an air intake 56 and a float 57 . The float 57 provides buoyancy for deploying the snorkel line 55 from the snorkel reel 53 . A radio antenna 58 and video camera with microphone 59 are mounted atop the snorkel 16 , and may be rotated 360 degrees. An entry guide cone 60 is provided for assisting entry of the snorkel 16 back into the housing 51 when the snorkel line 55 is being retracted back onto the snorkel reel 53 . An air supply outlet 61 is provided at the snorkel reel 53 .
FIG. 14 and FIG. 15 are partial cutaway drawings of the emergency flotation system 18 . The flotation system has a housing 63 with an upwardly disposed deployment hatch 64 . Both permanent floats 65 and inflatable bladders 66 are provided, with the inflatable bladders 66 preferably initially in a deflated, packaged condition. An end view shows the cylindrical high pressure bottles 67 that are provided for inflating the inflatable bladders 66 . A cable storage reel 68 is provided for spooling a tethering cable 69 , with a cable release 49 for deploying the emergency flotation system 18 . A motor 62 is provided for selectively retracting the tethering cable 69 after deployment. Operation of the emergency flotation system 18 is done manually or automatically through sensors and through system controls signals causing the activation of the reel release that will signal the flotation system to be buoyed to the surface by the floats 65 . The bladders 66 will then be automatically inflated by the bottle gas 67 . This is a “wet” system. The above view is near the rear topside of the ballast tank utilities 9 . These bladders will be automatically inflated with bottle gas upon reaching the surface and will enlarge by a factor of about 400.
FIG. 16 is a cutaway drawing for the upper stabilizer-rudder 8 , located near the rear of the power generator 2 . The stabilizer-rudder 8 has a hinge and support assembly 70 , pivotally connecting a movable portion to a stationary portion of the stabilizer-rudder 8 . A power shaft 71 is connected at one end to a worm gear box driven by a two-way electric motor 74 with the other end movably affixed to a bell crank 72 in order to provide sideways movement of the movable portion of the stabilizer-rudder 8 . The mechanical configuration for the movement of the stabilizer-rudder 8 is virtually identical for stabilizers 10 and 13 .
FIG. 17 and FIG. 18 are partial, cutaway views of one of the azimuth thrusters 17 . A power cable 76 provides power to a 360 degree horizontal rotator 77 . The rotator 77 is mounted to a frame 82 and has a rotary portion which is connected to a shaft 83 . An electric motor 79 and a thruster cowling 78 are connected to the lower end of the shaft 83 . The rotator is selectively powered to rotate the shaft 83 with the thruster cowling 78 and an electric motor 79 beneath the frame 82 . A rotary of the electric motor 79 is connected to a drive propeller 81 . A nose cone 80 is mounted to an outward end of the electric motor 79 . The horizontal rotator 77 enables the thruster 17 to be rotated 360 degrees for complete control of horizontal transit of the power generation system 1 .
FIG. 19 and FIG. 20 are partial cutaway drawings of an anchor cable reel 85 for selectively spooling the anchor cable 11 to secure the power generation system 1 in selected positions within ocean currents. The anchor cable reel 85 is preferably mounted directly to a frame of the power generation system 1 on the forward and the rearward ends and an underside of the power generation system 1 . The anchor cable reel 85 has a cable spool 86 about which the anchor cable 11 is selectively wound or from which the cable 11 is deployed. An electric motor 87 is operatively connected to the cable spool 86 . Power is preferably supplied to the electric motor 87 by a power cable 88 .
Example Application
As an example potential application area of the amount of power that could be produced from the present invention, the Florida Straits is an eastern offshore Florida region that is axially oriented north-south and contains some of the world's fastest marine currents and are relatively close to shore. These currents carry virtually all of the Gulf of Mexico water mass through the narrow straits area and north to the New England regions and beyond. Other significant world wide areas include the Kuroshio, offshore eastern Japan and Agulhas Current, offshore eastern Africa. This example application also demonstrates the increase in current velocity and corresponding power increase resulting from the use of the Bernoulli Principle.
The Florida Straits have been the subject of a number of oceanic studies owing to the significant potential of power that might be converted from hydrodynamic energy carried by the currents that may be subject to meandering. This power could be utilized by the large population centers in eastern Florida, such as Miami, that is located in the straits region. These currents have a maximum velocity of about 5.0 knots (2.57 meters/second). The area for this example is located east of Miami on an east-west line beginning about 16 kilometers east of Miami and ending some 42 kilometers east of Miami, thus resulting in a width of approximately 26 kilometers covering the fastest part of, and perpendicular to, the Florida Straits. The current velocity over the 26 kilometer width averages about 3.50 knots (1.80 meters/second) where the currents are subject to periodic meandering of varying degrees. The north-south length of the Florida Straits is over 1,000 kilometers while the depth is in the order of 400 to 900 meters.
The following would apply to the present invention, a counter-rotating, twin turbine, self-propelled, remote controlled submersible power generating system that is capable of self-transiting in meandering currents:
Given:
Velocity of Ocean Current,
v C = 1.80 M/sec (3.50 kts)
Diameter of Inlet (current amplifier 3),
D i = 60.97 M (200 Ft.)
Area of Inlet (current amplifier 3),
A i = 2,919.6 M 2 (31,416 Ft.) 2
Diameter of Outlet (turbine 12),
D T = 18.29 M (60 Ft.)
Area of Outlet (turbine 12),
A T = 262.7 M 2 (2,827 Ft.) 2
Ratio,
A i to A T = 11.11:1.00
Density of Seawater,
d S = 1,023 Kg/M 3
System Hydraulic Estimated Efficiency,
E H = 80%
Turbine Estimated Efficiency,
E T = 90%
Generator Estimated Efficiency,
E G = 95%
Combined Efficiencies,
E C = Product of
[E H ][E T ][E G ] = 68.4%
Depth to Ocean Floor,
380 M (1,246 Ft.)
Depth to Top of Power Generation,
55 M (180 Ft.)
System 1 to Avoid Surface Traffic
Determine:
Power Available at Inlet (current amplifier 3 ), P I =W (watts) Power to be Delivered (at export, turbine 12 ), P T =W (watts) Where, P T =[P I ][E C ]
Assuming seawater has negligible compressibility for this estimate, the power available from one power generator at the inlet cross section area based on a steady-state mass flow rate is:
P
I
=
[
0.5
]
[
d
S
]
[
A
i
]
[
v
C
3
]
=
[
0.5
]
[
1
,
023
Kg
/
M
3
]
[
2
,
919.6
M
2
]
[
1.80
M
/
sec
]
3
=
8
,
709
,
360
W
Then delivered power becomes,
PT
=
[
8
,
7909
,
360
W
]
[
0.684
]
=
6
,
000
,
000
W
(
rounded
)
power
from
one
power
generator
2
delivered
into
power
and
utility
line
4.
Thus, 12,000,000 watts would be the total power produced by twin generators 2 as delivered into power and utility line 4 . This delivered power would be sufficient to service about 10,000 average households.
In this example it is obvious that several power generation system 1 units could be coupled to deliver significant amounts of power for the Miami area.
It should be noted that without the use of current amplifier 3 and the intake of seawater currents through the turbine 12 only, the above 12,000,000 W of power would be reduced to only about 1,567,000 W or a reduction of some 87% using the above equations.
v T , the current velocity at turbine 12 entry of is also increased substantially compared to the 1.80 M/sec velocity at current amplifier 3 as noted from the equation of continuity:
[ A T ][v T ]=[A I ][v C ]
Where, Area of Inlet (current amplifier 3 ), A I =2,920 M 2 Area of Outlet (turbine 12 )=A T =263 M 2 v T =[2,920 M 2 ][1.80 M/sec]/[263 M 2 ]=19.98 M/sec
After considering the effects of E H , V T reduces to approximately 16 M/sec, which is about nine times as great as the 1.80 M/sec seawater velocity. This nine-fold increase in velocity is the result of seawater conically passing through current amplifier 3 where the Bernoulli Principle is applied.
The discussion above has focused primarily on embodiments of the invention employing renewable power generation by means of a tethered, submerged generating system for converting hydrodynamic energy from high sea currents to electricity for lower cost to the consumer. The invention is self propelled in order to mobilize and to redeploy to alternate locations since many desirable locations for offshore power generation are in regions of meandering currents. The invention also has the means to significantly increase the speed of ocean currents passing through the system to much higher levels to allow greater amounts of power generated and to permit its operating in areas of lower current speeds. It should be understood that the inventive concepts disclosed herein are capable of many modifications. To the extent such modifications fall within the scope of the appended claims and their equivalents, they are intended to be covered by this patent.
The present invention provides the following unique features for offshore, subsea devices for generating power:
1. ROBOTIC OPERATION—All of the inventions operations may either be preprogrammed or conducted manually by means of either a connecting power delivery cable to shore control or by radio control through a snorkel (See 6 , below).
2. CURRENT AMPLIFIER—A retractable cone-like device constructed of a flexible material with a rigid framework and configured for ocean currents entering the large end of the cone and expelled at the small end at a much higher velocity in accordance with the Bernoulli Principal, first published in 1738. The resulting higher velocity significantly increases the power density of current entering the turbine for much greater amounts of power production at a lower cost.
3. MARINE LIFE PROTECTOR—A grid-like cover that fits over the current amplifier to prevent marine life from entering the current amplifier/turbine.
4. RETRACTION UNIT—A device that retracts the current amplifier and marine life protector resulting in a streamlined body suitable for transportation while submerged. The current amplifier and marine life protector are also deployed by the retraction unit at the selected location of anchoring.
5. SELF-PROPELLED FEATURE—The invention can move independently to selected locations to position itself in areas of faster meandering marine currents that often behave in a manner similar to atmospheric “jet streams.” This self-propelled means is provided by azimuth thrusters that move the device in any lateral direction in concert with the air/water ballast system for precise positioning of the invention for optimum power production.
6. SNORKEL—A tubular device extended vertically from the invention to the atmosphere to provide ballast air and a means of radio communication with shore management.
7. ANCHOR SYSTEM—That is remote controlled from the shore management location for either setting anchors in a selected pattern or retrieving them for transit.
Although the preferred embodiment has been described in detail, it should be understood that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
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A self-propelled, robotic power generating system remains submerged in deep water areas, tethered within steady-state, generally unidirectional sea currents in non-tidal areas for the continuous production of turbine-generated electricity that is transmittable by multipurpose undersea power cable to onshore electric grids. System aspects include a shore-to-system communication means to remotely manage all system functions; a sea current intake consisting of a cone-like, retractable current amplifier to significantly increase the energy density of the currents passing through the amplifier to the turbine; a self propulsion means to move the system to maintain a desirable location within a prescribed area that may be subject to meandering currents; a snorkel-like vertical air conduit for ballast control; a seawater pumping means for ballast control; a retractable marine wildlife protector to cover the sea current intake; and a remotely retractable anchor means to maintain the generating system in a target position for extended time periods.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser. No. 12/077,045 filed Mar. 14, 2008, which is a continuation of U.S. application Ser. No. 11/888,850 filed Aug. 2, 2007, now U.S. Pat. No. 7,730,149, which applications claim priority under 35 USC 119 of United Kingdom Application GB 0621874.7 filed Nov. 2, 2006, the entire disclosure of each of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a method of, and system for, controlling access to a plurality of communications sessions involving a plurality of users, and is particularly, but not exclusively, suitable for allocating a group of users to a communications session based on a match between characteristics of a given communications session and characteristics associated with the group.
BACKGROUND INFORMATION
[0003] As is well known, communications networks provide a means for users to communicate with one or more other users. Users of a communication system are typically provided with numerous services, such as calls, data communication such as messaging and/or multimedia services, or simply provide users with a gateway to another network, such as the Internet. In relation to any one service, various communication systems, such as public switched telephone networks (PSTN), wireless communication systems, e.g. global system for mobile communications (GSM), general packet radio service (GPRS), universal mobile telecommunications system (UMTS), wireless local area network (WLAN) and so on, and/or other communication networks, such as an Internet Protocol (IP) network, may simultaneously be concerned in providing a connection. An end-user may access a communication network by means of any appropriate communication device, such as user equipment (UE), a mobile station (MS), a cellular phone, a personal digital assistant (PDA), a personal computer (PC), or any other equipment operable according to a suitable network protocol, such as a Session Initiation Protocol (SIP) or a wireless applications protocol (WAP) or a hypertext transfer protocol (HTTP). The user equipment may support, in addition to call and network access functions, other services, such as short message service (SMS), multimedia message service (MMS), electronic mail (email), Web service interface (WSI) messaging and voice mail and one-way messages such as WAP PUSH messages.
[0004] Communications services involving more than two users are generally referred to as group communications services, and include the “push-to-talk over cellular” (PoC) service also known as the PTT (push-to-talk service), the instant messaging (IM) service, IRC (“Internet Relay Chat”), and the ICQ (“I Seek You”) service. In the case of the IM service, users are allowed to send messages to one or more in a list of predetermined users (a so-called “private list”) in a conversational mode, and because they are transmitted “instantly”, the transfer of messages back and forth is fast enough for participants to maintain an interactive conversation. The IRC service is a system for chatting that involves a set of rules and conventions and is implemented via client/server software. An IRC client can be downloaded to a user's computer, and the client is then used to connect to an IRC server in an IRC network to start or join an IRC chat group. The fourth group messaging application, ICQ (“I Seek You”), is a client application that provides information as to which “friends” and “contacts” are also online on the Internet, pages them, and operates so as to coordinate a “chat” session with them. The IM system is similarly arranged to generate alerts whenever a member of a given private list is online.
[0005] When designing a service, the objectives of the service provider—in terms of their effect on end users—have a significant bearing on the technology that is selected to support the service. For example, services that are designed to deliver information to a selected group of users (with a view to triggering a particular action to be taken on the part of the group members) make use of technology that is designed to match characteristics of the users with those of the information so as to improve the match between what the user receives and what the user wants to receive. Typically such information is delivered from a single source to many recipients, and any subsequent interactions proceed between the recipient and communications devices related to the information source.
[0006] As will be appreciated from the foregoing, in addition to transmitting information from one→one and one→many recipients, information can be distributed between members of a group so as to encourage discussion between—and thus impact on—group members, thereby increasing the effectiveness of the information. As described above and in international patent application having publication number WO2006/027407, known group communications methods involve discussions between predetermined or specified members of a group. Thus whilst known group communications services provide a means of increasing the impact of information on users, the extent of this impact is nevertheless limited to that achievable within a closed group of recipients.
SUMMARY OF THE INVENTION
[0007] In accordance with one aspect of the present invention, there is provided a method of controlling access to a communications session. Embodiments of the invention thus provide a means of selecting a communications session, or discussion forum, to host a group discussion between members of a group of users, and thus advantageously provide a means of controlling the context for discussion among the group members.
[0008] The members of the group are preferably notified of the selected communications session via a WAP message, which contains a link to the communications session, while selection of the communications session can be triggered by receipt of a short message—such as an SMS message—from a member of the group. The SMS message conveniently identifies the group and can contain a line of text or image that the member wants to pass on for discussion. Since the majority of terminals are capable of sending and receiving SMS and WAP messages, the terminals of participating group members do not need to have any bespoke software applications installed on their handsets in order to make use of the new service.
[0009] According to another aspect of the present invention there is provided a method which provides a means for groups of users to take part in communications sessions involving participants of a publicly accessible and interactive communications session, and thus provides a mechanism for information to be discussed and disseminated—in a particular period of time—by a wider audience than is possible with present methods.
[0010] Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic diagram showing a mobile network and network components arranged in accordance with an embodiment of the invention;
[0012] FIG. 2 is a schematic block diagram showing in detail the functionality associated with a distribution server shown in FIG. 1 ;
[0013] FIG. 3 is a schematic flow diagram showing a process for coordinating group participation in a communications session according to an embodiment of the invention; and
[0014] FIG. 4 is a schematic diagram showing an example of an outgoing message created by the distribution server shown in FIG. 2 .
DETAILED DESCRIPTION
[0015] As described briefly above, embodiments of the invention are concerned with coordinating access to a communications session, specifically coordinating access by a predetermined group of terminals to one of a plurality of available communications sessions.
[0016] Identification of the group members and the methods of providing members with access data for enabling access to the communications session will be described in detail later in the description, but first a description of the infrastructure needed to coordinate access to the communications session will be described.
[0017] FIG. 1 shows an example of a data messaging system 100 within which embodiments of a first aspect of the invention operate; the arrows indicate data flows within the data messaging system 100 and the objects indicate components of the data messaging system 100 . This Figure shows an arrangement of network components suitable for the delivery of WAP messages, Short Message (SMS messages), Multimedia messages (MMS messages), bespoke messages in the form of GPRS data and/or streamed data; as will be appreciated, the specific arrangement of the data messaging system 100 is dependent on the type of message being used to facilitate the coordination.
[0018] In the arrangement shown in FIG. 1 , a terminal T 1 communicates with various network devices within the data messaging system 100 . The terminal T 1 may be a wireless terminal such as a mobile phone, a PDA or a Laptop computer, or it may be a fixed terminal, e.g. in the form of a Personal Computer. In the arrangement shown in FIG. 1 the data messaging system 100 comprises: a WAP gateway 7 , which is typically a network operator's WAP gateway; a distribution server S 1 ; and a database DB 1 , arranged to store at least some of:
data in respect of users of the data messaging system 100 , including data identifying interests and characteristics of individual users and groups of users; data in respect of terminals such as terminals T 1 , T 2 , T 3 and T 4 ; data in respect of tagging content, including image (static, dynamic and/or interactive images), alphanumeric characters and content control information, the data having been provided by various content providers CP 1 , CP 2 ; and communications sessions data in respect of communications sessions, including: data identifying sponsors; demographic requirements (in terms of types of users who are preferred participants of a given communications session); priority information; and status information (e.g. active, inactive etc.). The communications sessions, and thus sponsor, demographic and priority information, can be related to the content providers CP 1 , CP 2 .
[0023] In one arrangement the distribution server S 1 and the database DB 1 are located within a proprietary network, which means that they operate independently of any specific network operator and can be shared across a plurality of network operators. Using techniques known in the art, the database DB 1 can store the preference and demographic data that are used to control selection of a communications session, or discussion forum, as described below.
[0024] The functionality of the distribution server S 1 will now be described with reference to FIGS. 2 and 3 . In addition to standard CPU, memory, data bus, Input/Output ports, data storage, and operating system programs, the distribution server S 1 comprises certain bespoke functional components, namely:
tagging data selector software component 201 for selecting tagging data from the database DB 1 ; message analyser component 203 for identifying group members that are to be joined with the selected communications session; and outgoing message generator component 205 for selecting a communications session to which the group members are to be joined and for creating messages that include access data enabling recipients of a given message to join the selected communications session.
[0028] In a first embodiment the incoming (or initiating or originating) message M 1 is an SMS message originating from the terminal T 1 ; the originating message M 1 contains a message body and carries details of a group of recipients such that the incoming message analyser 203 can identify the group identifier from the message. In one arrangement, during message creation the sending terminal T 1 prompts the sending subscriber to select a group from a preconfigured list of groups stored on the terminal T 1 , causing the terminal T 1 to create an SMS message identifying the selected group and having a format compatible with the format requirements of the message analyser component 203 . This arrangement presupposes that the message analyser component 203 has access to the predetermined groups and members thereof.
[0029] In an alternative arrangement, the user of the terminal T 1 enters an identifier for a group manually within the content of the SMS message M 1 ; for example groups could be identified by numbers or by special characters, such as: “% This is a group message”, “#This is a group message”, “&This is a group message”, where first one would be forwarded to group identified with %, second with # and third with &. As for the first arrangement, the group members corresponding to a given character would be accessible to the message analyser component 203 (such special character definitions groups could be specified via web interface).
[0030] In a yet further arrangement, and instead of selecting a group identifier that relates to a predetermined set of group members, the sending terminal T 1 could prompt the user to simply select “Group” from a list of possible message types, without selecting a specific group identity. In this arrangement the terminal T 1 would create an SMS message identifying that message M 1 is intended to spawn creation of a group message, but identification of the group members would be a process performed by the message analyser component 203 , and thus in real time rather than based on any predetermined group lists. In a yet further arrangement the terminal could be configured to analyse the content of individual messages, and for those whose content is determined to be identical to that of other messages, the terminal could send out a single message with an identifier indicating the message to be of a group type.
[0031] The message M 1 could include additional information entered at terminal T 1 , such as keywords identifying subject matter of particular interest at the time of sending the message, and these can be used by the tagging data selector 201 when selecting the communications session to which the group members are to be joined.
[0032] In any of these arrangements, the destination address of the SMS message M 1 would be the network identity of the server S 1 .
[0033] For an arrangement in which individual messages are sent out to individual recipients (without analysis by the terminal T 1 in the manner specified above), the message analyser component 203 would either be directly associated with SMSC 3 , or the SMSC 3 would be provisioned with specific forwarding instructions in respect of individual recipients so as to ensure that the individual SMS messages M 1 are forwarded to the server S 1 . Once received, the message analyser component 203 would analyse the content of individual messages so as to determine those having identical content, and deriving a group on the basis of the content of the messages M 1 .
[0034] It will be understood from the foregoing that the function of the message analyser component 203 is at least to derive the identities of group members to whom communications sessions invitations are to be sent. These process steps are indicated in FIG. 3 by S 3 . 1 and S 3 . 3 .
[0035] Turning now to the creation of messages inviting group members to communications sessions, the outgoing message generator 205 is arranged to create individual invitation messages M 2 a, M 2 b, M 2 c, one for each member of the group identified by the message analyser component 203 . In one embodiment these messages M 2 a, M 2 b, M 2 c are embodied as WAP messages; WAP is a convenient choice of format for the outgoing messages because it allows links such as URLs and the like to be included within a message, these being displayed as a selectable object on a recipient's terminal which, when selected, cause the terminal to retrieve data from the network address associated with the object.
[0036] As described above, embodiments of the invention are concerned with coordinating the joining of members of a group to a communications session, and the links that are inserted into a given WAP message M 2 a, M 2 b, M 2 c created by the outgoing message generator 205 include links to discussion forums and the like. Preferably at least some of the discussion forums are publicly accessible so that, in at least some embodiments, whilst a group identifier is used to select individuals to involve in a communications session, the communications session to which they are invited to attend is not limited to group members only. This differs significantly from conventional methods such as those described in international patent application having publication number WO06/027407, where the group identifier serves both to identify individuals to involve in a given discussion, and to define the participants in the discussion. Selection of a communications session can be dependent on attributes such as keywords specified in the initiating message M 1 (if available), and/or time of receipt of the initiating message M 1 , and/or profile data corresponding to the group and/or one or more of the identified group members. Accordingly, upon receipt of the group member identities, the outgoing message generator 205 is arranged to access the database DB 1 and retrieve interests and preference data corresponding to at least some of the group and/or individual group members, and to compare these data with attributes of currently active and accessible communications sessions. The attributes of a given communications session include a set of demographic requirements, these having been specified by the host of a given communications session and being matched against the preference and interests data corresponding to individuals of the group G (or the group itself), thereby effectively controlling which types of groups are allowed to access a given communications session. In addition the attributes can include priority information, this having been specified or negotiated by a content provider CP 1 , CP 2 (for example) and being used by the outgoing message generator 205 when selecting a specific communications session from those available.
[0037] An example outgoing, or invitation, message M 2 a including a link 401 to a communications session is shown in FIG. 4 : the link 401 is embodied as a selectable object and is identifiable from the text “Press here to chat!”
[0038] The outgoing message generator 205 can also cooperate with the tagging data selector software component 201 so as to select and insert information tags (such as those identified by reference numerals 403 , 407 ) into the invitation messages M 2 a, M 2 b, M 2 c. The tagging software component 201 is arranged to select image and/or text and/or audio and/or video tagging data on the basis of demographic data corresponding to one or more of the identified group members and from the repository of tagging data stored in the database DB 1 and/or the text contained within the initiating message M 1 . For the example shown in FIG. 4 , it can be seen that the text 405 of the initiating message M 1 has been used to select both the image tag 403 and the text tag 407 : the invitation messages M 2 a, M 2 b, M 2 c include the text 405 included in the initiating message M 1 , together with information as to the origins of the invitation messages M 2 a, M 2 b, M 2 c (“Message from Pete . . . ”) thereby providing suitable context for the tag data 403 , 407 when the invitation message M 2 a is reviewed by a recipient. The foregoing message creation process is indicated generally in FIG. 3 at step S 3 . 5 .
[0039] In view of the fact that the tags 403 , 407 are included with the link to the selected communications session, it will be appreciated that these tags 403 , 407 can be used to steer group discussions within the communications session towards the subject matter of the tagging data, for example with incentives in the event that any participant of the group communications session purchase certain goods—from certain providers—during the communications session (or within a specified period thereafter).
[0040] Furthermore, since the link 401 is the trigger for the IM chat session, the tags 403 , 407 accompanying the link 401 essentially serve to announce or promote the selected communications session. Thus in at least some embodiments, the data to be selected for inclusion in a given message are advertisement data, and in the case of the advertisement data relating directly or indirectly to the communications session associated with the link 401 , the tags 403 , 407 could identify a sponsor thereof.
[0041] Once the WAP messages M 2 a, M 2 b, M 2 c have been created, they are sent to the recipients identified at step S 3 . 3 via the WAP gateway 7 (step S 3 . 7 ), as is known in the art. It is to be noted that whilst not shown in FIG. 1 , a WAP message is also preferably sent to the terminal T 1 from which the initiating message M 1 was received (in this example, Pete's terminal).
[0042] The transmission of the WAP messages M 2 a M 2 c marks the end of the involvement of the distribution server S 1 , since selection of the link 401 is transmitted to network components associated with the link, and this process is independent of the distribution server 51 . Thus, if activation of the link 401 results in a HTTP request message to be transmitted to a web server running an IM chat session for example, subsequent messages would be transmitted in accordance with IM and its associated protocols (step S 3 . 9 ).
[0043] Whilst in the embodiments described above the message M 1 is an SMS message, it is to be understood that message M 1 could alternatively be a USSD, MMS, email or any other type of message capable of identifying a group of recipient terminals. Similarly, whilst in the above embodiments the outgoing messages are embodied as PUSH WAP messages, they could alternatively be embodied as MMS messages, SMS messages with link in text form, bookmarks to mobile terminal, e-mail, voice call, broadcast message using cellular networks (such as Multimedia Broadcast/Multicast Service (MBMS) over Wideband Code Division Multiple Access (WCDMA)) or broadcast messages using broadcast networks (such as Digital Video Broadcast—Handheld (digital TV) (DVB-H), Integrated Services Digital Broadcasting—Terrestrial (ISDB-T), Digital Audio Broadcasting (DAB), Forward Link Only (Qualcomm) (Flo), Digital Multimedia Broadcasting (DMB), Radio Data Service (RDS) channel of radio network to mention few), any multicast or broadcast IP session indicator protocol.
[0044] In the above embodiments, access to a communications session is described in relation to a single group. However, selection of a communications session could be made on the basis of the identity—and thus demographic data—corresponding to groups that have already been notified of a communications session. Thus in addition to reviewing priority and demographic requirements of a given communications session, the outgoing message generator 205 could be arranged to review the identity of groups to whom invitation messages have previously been sent, and compare the demographic data between the respective groups in order to select a communications session for the subsequently requesting group members.
[0045] The above embodiments are to be understood as illustrative and non-limiting examples of the invention, which is concerned with facilitating access to discussion forums by predetermined groups of users. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.
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An interactive system and method for controlling access to a plurality of communications sessions involving a plurality of users including controlling access to a plurality of communications sessions, each of said communications sessions being for access by a plurality of users, wherein data identifying said plurality of communications sessions have been stored in association with data indicative of one or more characteristics thereof. The method includes receiving a request to initiate communications among members of a group of users, wherein said request includes data identifying the group of users, responsive to receiving said request, selecting a communications session on the basis of data identifying the group and at least some of said stored data indicative of characteristics of a given communications session, and transmitting messages to at least some members of the group. Each message has a message body including data providing access to the selected communications session and a destination address determined from data indicative of a given member of the group.
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BACKGROUND OF THE INVENTION
This invention relates to the field of power dividers and, more specifically, to the use of such dividers with radio frequency (RF) power sources.
Power control systems which deliver input RF power to several output ports are typically very lossy. Many of such systems use transformers and transmission lines coupled to absorptive attenuators. Unfortunately, these systems do not deliver a large amount of their input power to their output ports, so such systems are not power efficient. Furthermore, many of these systems deliver power to output ports which have been turned off, which wastes power and makes it unavailable for other output ports.
For example, U.S. Pat. Nos. 4,028,632, 3,986,147 and 3,928,804 to Carter et al describe systems having an N-port circulator and isomismatch devices. The impedance mismatches, however, are fixed impedance transmission line mismatches and are not remote-controllable.
One of the objects of this invention is a highly efficient power controller which delivers virtually all of the input RF power to its output ports.
It is also an object of this invention to have a power efficient power controller which can be connected to a variable number of output ports.
Another object of this invention is a power controller which delivers power to several output ports and which can be easily adjusted to deliver no power to output ports that are turned off.
Yet another object of this invention is an efficient power controller which allows easy adjustment of the amount of power switched to any of its output ports.
Additional objects and advantages of this invention are set forth in the description which follows and in part would be obvious from that description or may be learned by practice of the invention. The objects and advantages of this invention may be realized by the apparatus pointed out in the appended claims.
SUMMARY OF THE INVENTION
The power controller of this invention uses variable reactive elements in its power distribution circuitry to deliver virtually all of the input power to the output ports. By using variable reactive elements, the amount of power delivered to any output port can be easily adjusted. If an output port is turned off, the power distribution circuitry can be adjusted to deliver virtually no power to that port.
The total power from the input (less insertion loss) source is always available to those ports which are still active. Virtually none of the power is absorbed at the off ports and the total power available may be apportioned as desired to the active ports.
To achieve the objects and in accordance with the purpose of this invention, as embodied and as described below, the power controller of this invention comprises a source of input power; a plurality of power output ports; and a first number of power distribution means coupled to the input power source and the power output ports for delivering substantially all of the input power to the plurality of output ports, each of the power distribution means receiving a fraction of input power, selectively transmitting a portion of that fraction of the input power to the output ports coupled to that power distribution means, and reflecting out the portion of the fraction of input power not transmitted to its coupled output ports.
More specifically, a power controller according to this invention for selectively distributing power supplied by a power source to n (where n is greater than one) output ports comprises n-1 circulators connected in series between the power source and an nth output port; and n-1 variable reflection coefficient devices each associated with and connected to a different one of the circulators and to a different one of the output ports, each of the variable reflection coefficient devices receiving input power from its associated circulator, transmitting a selective portion of the received input power to its associated output port, and reflecting back to its associated circulator the portion of the received input power not transmitted to its associated output port.
The accompanying drawings, which are incorporated in and which form a part of the specification, illustrate embodiments of the invention and, together with the description, explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an embodiment of a power controller of this invention for supplying input power to two output ports;
FIGS. 2 and 2a show variable reflection coefficient devices which can be used with the power controller shown in FIG. 1;
FIG. 3 shows a branch line coupler which can be used with the varable reflection coefficient device shown in FIG. 2; and
FIG. 4 shows an embodiment of a power controller of this invention for supplying input power to several output ports.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a power controller 1 according to this invention which supplies input power from an RF input port 10 to output ports 21 and 22. In accordance with the present invention, the power controller includes a first number of power distribution means coupled to a source of input power and to power output ports for delivering substantially all of the input power to the output ports. Each of the power distribution means receives a fraction of input power, selectively transmits a variable portion of that fraction of input power to the power output ports coupled to that power distribution means, and reflects out the portion of the received fraction of input power not transmitted to its coupled output ports. In power controller 1 shown in FIG. 1, circulator 30 and variable reflection coefficient device 40 receive input power from RF input port 10, transmit a portion of that power to output port 22, and reflect out to the output port 21 via a power distribution line 23 the portion of the input power not transmitted to output port 22.
Circulator 30 is a conventional three terminal circulator. It sends the RF power from RF input port 10 into input/output terminal 41 of variable reflection coefficient device 40. It also sends to output port 21 via the power distribution line 23 any reflected power received from device 40 via input/output terminal 41.
The present invention also includes means for setting a reflection coefficient between zero and one to indicate the portion of power to be transmitted to the associated output port. Variable reflection coefficient device 40 has a set terminal 43 which is used to adjust the transmission coefficient r, or alternatively the reflection coefficient 1-r, of device 40 to a value between zero and one. The transmission coefficient r indicates what portion of the power received from input port 10 will be transmitted to output port 22, while the reflection coefficient 1-r indicates what portion of the RF input power is reflected back through circulator 40. For example, when r=0.1, only one tenth of the input power is transmitted to output port 22 and nine-tenths of that power is reflected.
Since the portion of the input power which is not transmitted to the output port is reflected back out to circulator 32 and to output port 21, virtually all of the input power from RF input port 10 is divided between output ports 21 and 22. By adjusting set terminal 43, the portions of the input power outputted to ports 21 and 22 can be adjusted. If output port 22 is turned off, for example, then r of device 40 can be set to zero so virtually all of the input power will be delivered to output port 21.
An embodiment of the variable reflection coefficient device 40 is shown in greater detail in FIG. 2. Device 40 includes a branch line coupler circuit 45, an example of which is shown in FIG. 3. Branch line coupler circuit 45 in FIG. 3 is a microstrip circuit which includes two horizontal legs 142 and 144 and two vertical legs 141 and 143 connected to form a square. The width of the horizontal legs and of the vertical legs are different. For example, for the 3 db coupler required for circuit 45, the series impedance should be 35.35 ohms and the shunt impedance should be 50 ohms. So in this case is also assumed to be 50 ohms. For a microstrip circuit in a circuit board whose dielectric constant is 2.2 and thickness is 0.010 inches, a 50 ohm line is 0.031 inches wide and a 35 ohm line is 0.053 inches wide. The length of these lines is 1/4 of the center operating frequency wavelength.
Alternatively, branch line coupler circuit 45 could include a waveguide or a coaxial circuit.
In FIGS. 2 and 3, input/output terminal 41 is shown in the upper left hand corner of device 40 and the output terminal 42 is shown at the lower left hand corner of device 40. Without any external circuitry, branch line coupler circuit 45 would divide the input power received at terminal 41 such that half of the power would appear at the upper right hand corner of circuit 45 and half the power would appear at that circuit's lower right hand corner. By adding reactive components to the upper and lower right hand corners of circuit 45, the amount of input power transmitted to output terminal 42 and reflected out of input/output terminal 41 can be adjusted.
In FIG. 2, the lower and upper right hand corners are denoted as 48a and 48b, respectively. In accordance with the present invention the power controller of this invention includes a variable reactive means coupled to the branch line coupler circuit. In FIG. 2, a transmission line 50 of length l 1 and varactor diode 52 are coupled to terminal 48a. Similarly, transmission line 60 of length l 2 and varactor diode 62 are coupled to terminal 48b. The length of transmission lines l 1 and l 2 can have the same or different lengths depending upon the application.
Varactor diodes 52 and 62 provide a variable capacitance at RF frequencies. Each varactor diode and transmission line combination provide a specific reactance for the variable reflection coefficient device 40. The value of the reactance provided at terminals 48a and 48b determines the value of r for device 40.
The value of the reflection coefficient seen at terminals 48a & b is proportional to impedance mismatch between the hybrid transmission line impedance and the impedance of the reactance element at the operating frequency. For example if the impedance at 48a is 50 Ω(Z MIN) and the impedance at the end of l 1 was 70 Ω(Z MAX) the reflection coefficient can be calculated by: ##EQU1## For this example 1-r=0.167.
The lengths of transmission lines l 1 and l 2 have the property of altering the actual impedance seen at the output ports 48a & b due to the varactor diode. These transmission line lengths and their characteristic impedance alter the limited impedance range of the varactor diode and transform this into the desired values to achieve high and low levels of reflection coefficients.
The operation of elements 50-54 will be described with the understanding that elements 60-64 behave analogously. A voltage variable capacitance device, such as the varactor diode 52 has a capacitance that is determined by the voltage across that diode. To set that voltage, RF choke 53 and a variable power supply 54 are connected to the junction of varactor diode and transmission line 50.
Typically, RF choke 53 is a transmission line which is one or two times narrower than transmission line 50. RF choke 53 isolates the RF signals from power supply 54 because it appears as a very high impedance to RF frequency signals. To the constant voltage signals from power supply 54, however, choke 53 appears as a very low impedance, hence the bias voltage from supply 54 can pass through choke 53 to a set the capacitance of varactor diode 52.
To provide an even higher impedance for the input RF power, the length of RF choke 53 is set to about 1/4 of the wave length of the RF power and the RF choke is connected to the power supply by large printed circuit board capacitors (65, 66) to ground which act as low impedance at RF frequencies.
The capacitance of DC blocking capacitors 67 and 68 is chosen to be large at the RF operating frequencies so that they contribute an insignificant reactance or impedance in the circuit. Alternatively, DC blocking capacitors 65 and 66 may be removed if RF chokes 53 and 63 are moved directly to the left of varactor diodes 62 and 52 and connected across those diodes as in FIG. 2a.
The voltage of power supply 54 is set via terminal 43a just as the voltage of power supply 64 is set by terminal 43b. Preferably, terminals 43a and 43b are electronically controlled for speed and convenience. Terminals 43a and 43b together form set terminal 43 in FIG. 2.
For example, if the varactor diodes 52 and 62 are set to 1 picofarad, reactance of a 1 picofarad capacitor at 100 Megahertz operating frequency is computed by: ##EQU2##
The reflection Coefficient due to this reactance is computed if for example the impedance at 48a is 50 ohms. ##EQU3##
FIG. 4 shows an embodiment of the present invention to divide input power for N output ports. A circulator and a variable reflection coefficient device correspond to all but output port N. Specifically, output port 1 corresponds to circulator 200 and variable reflection coefficient device 203, output port 2 corresponds to circulator 210 and variable reflection coefficient device 213, output port 3 corresponds to circulator 220 and variable reflection coefficient device 223, and output port N-1 corresponds to circulator 290 and variable reflection coefficient device 293. Output port N does not correspond to a circulator and variable reflection coefficient device, but N is coupled to circulator 290 and receives that portion of the input power which is not sent to any of the other output ports.
Circulators 200, 210, 220 and 290 function similarly to circulator 30 in that power input to a circulator is sent to the associated variable reflection coefficient device. That variable reflection coefficient device reflects certain of that power back to the circulator which then transmits that power via power distribution lines 204, 214, 224 and 294 to the next circulator or, in the case of circulator 290, to output port N.
The input voltage from RF input 10 is sent via circulator 200 to variable reflection coefficient device 203 having a transmission coefficient, r 1 . The voltage output to port 1 equals r 1 times the input voltage and the voltage reflected back through circulator 200 and into circulator 210 equals (1-r 1 ) times the input voltage. Circulator 210 delivers that reflected power into device 213 which has a transmission coefficient of r 2 . Thus, output port 2 receives r 2 of its incident input voltage or r 2 x (1-r 1 ) times the input voltage to the controller.
If r 1 and r 2 equaled 1/2, output port 1 would receive 1/2 of the RF input voltage and output port 2 would receive 1/4 that input voltage. The amount of voltage reflected into circulator 220 is also equal to 1/4 the input voltage.
The other variable reflection coefficient devices similarly split the power input to them between their output ports and the following circulator according to their reflection coefficients. The power reflected by variable reflection coefficient device 293 is output to port N.
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A multi-port power controller uses remote-controllable variable reactive elements to set the amount of power delivered to the ports.
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BACKGROUND OF THE INVENTION
The invention relates to window framing systems which use corner keys, and which seal against embossed surfaces, particularly for use in garage doors. The corner keys are insertable into hollow portions of extruded window frames and which preliminarily hold the window frame together prior to more permanent fastening within a garage door by a plurality of screws or even via a snap-fit arrangement. The angularity of at least two internal ribs of the corner key into which a fastener impinges thereupon, facilitates tightening engagement of each mitered window frame corner, leading to a superior appearance and preventing moisture from getting inside the window unit.
Consumers often request the inclusion of a series of decorative windows in garage doors. These windows are usually incorporated into the upper section of the garage door. The windows are formed in individual panels of the upper section and provide daylight illumination of the closed garage. A window opening is generally cut or preformed in each panel into which a window is to be inserted.
In the past, a rather cumbersome window and window framework system was inserted into the opening. Improvements to this base system included using a corner key to facilitate holding the mitered frame together, followed by insertion into the window opening and ultimate fastening to the garage door using screws. This process, while partially effective did suffer from some drawbacks. First, while the insertion of a corner key into hollow voids contained within the extruded plastic frames did initially hold the mitered window frame together thereby facilitating initial insertion of the frame into the opening, subsequent screwing of the frame into the garage door resulted in the creation of a gap between the mitered edges of the window frame as the frame was drawn close to the planar surface of the garage door. This gap leads to both an inferior exterior appearance as well as permitting rain or other external moisture to seep through the gaps created in the corners and migrate downwardly through the garage door panels, leading to internal rusting of the door and often through repeated exposure to moisture, unsightly water trails containing rust particles on both the exterior and interior garage door panels.
Additionally, the window framework system presented problems in sealing against the exterior, and possibly interior surface of a garage door, in that these doors almost always include some form of a decoratively embossed or bas-relief surface. This surface treatment provides important decorative and structural functions. Decoratively, this surface treatment is designed to mimic conventional wood panels while structurally it imparts a certain degree of dimensional stability to the garage door section. However, while an embossed surface is esthetically pleasing, the surface texture makes it difficult to effectively seal upon.
In the embossing process, a plurality of impressions are formed in a substrate, e.g., steel, by working rolls. Plateaus are formed between impressions. The inclination (i.e., slope) of surfaces of the substrate between plateaus and impressions is important for many reasons. It has been found to be an important surface feature with respect to premature corrosion, discoloration, and non-aesthetically pleasing appearance. Unduly high slopes of surfaces cause paint to flow downward into impressions leading to paint thinning at transition points between plateaus and impressions, which makes these sites prone to premature corrosion. Slopes which are too low, on the other hand, cause a loss of crispness in the painted embossed surface, which leads to a less aesthetically pleasing appearance. The balancing of these factors has additionally led to problems in trying to place and seal window frames into these highly embossed garage door panels, in that the linear distance between a recessed plateau and a raised impression is almost impossible to seal using a thin flexible strip of coextruded polymer, which is positioned on the raised impressions. While the thin flexible strip may sag between the raised impressions, it is not possible for this strip to physically conform into the plateaus, thereby inherently leading to a leaking situation.
The Prior Art solutions fail to effectively provide a window framework system which effectively seals against a high-relief embossed surface.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a shift in the paradigm of conventional wisdom and effects sealing engagement with an edge of an opening which has been cut into a garage door panel, rather than on the highly embossed surface.
It is an object of this invention to effect sealing engagement with the cut edge of a garage door panel with a flexible coextruded inwardly angled seal on the window frame, the opposite direction of conventional outwardly angled seals.
It is another object of this invention to use a corner key fastener for use in the decorative window system for a window opening in a garage door wherein the installation of the decorative window framing system is achieved by the use of these corner keys inserted into hollow extruded plastic window frame with subsequent attachment into the garage door by screws or snap-fit engagement with a mating engagement frame on an opposed side of the garage door panel.
It is an object of this invention to provide improvements in the area of the installation of garage door window systems.
It is another object of this invention to provide improvements in the formation of the decorative window systems by achieving a secure and tight framing system by imparting at least a non-transverse vector force component to the window frame by the deployment of at least a pair of angled ribs within the corner key. The use of these corner key fasteners in a window framing system achieves a more secure and tighter seal at the miter joint of the frame, thus preventing moisture, water, or other natural elements from entering the hollow interior of the garage door.
These and other objects of this invention will be evident when viewed in light of the drawings, detailed description and the pending claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may take physical form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein:
FIG. 1 is a plan view of a corner key in accordance with the present invention;
FIG. 2 is a sectional view of the key shown in FIG. 1 as may be taken at line 2 — 2 in the Figure;
FIG. 3 is a sectional view similar to FIG. 2 but showing a fastener as may be applied to the key;
FIG. 4 is a plan view of the opposite face of the key shown in FIG. 1 illustrating its application to a window framework which is illustrated in ghost lines;
FIG. 5 is a cross-sectional view of a window frame having hollow portions disposed therein showing a Prior Art outwardly facing sealing strip in ghost lines and an inwardly facing sealing strip of the present invention;
FIG. 6 is a cross-sectional view of a window frame of FIG. 5 showing the inwardly facing sealing strip sealing on an edge of one partially shown embossed garage door panel with a corner key of FIGS. 1-4 shown inserted into one hollow void in ghost lines; and
FIG. 7 is a cross-sectional view of a window frame of FIG. 5 showing the outwardly facing sealing strip sealing on an edge of one partially shown embossed garage door panel with a corner key of FIGS. 1-4 shown inserted into one hollow void in ghost lines.
DETAILED DESCRIPTION
Referring now to the drawings wherein the showing is for the purpose of illustrating the preferred embodiment of the invention only and not for purposes of limiting the same, the figures show a corner key which connects the framing system without resort to the installation methods involving either physical pounding or the use of machine screws with nuts alone in conjunction with an effective sealing method which is applicable to embossed surfaces.
As illustrated in FIG. 1, a 90° corner key device 10 is shown having two perpendicularly extending legs 12 , 14 joined at a common vertex 20 , and two ends 16 , 18 . One leg of the corner key device will be at least partially inserted into mating engagement with a first receiving longitudinal hollow void of an extruded plastic profile, while the other leg is at least partially inserted into mating engagement with a second receiving hollow void of an extruded plastic profile. While the device typically has a plane of symmetry, typically a mirror image opposed side, there is no requirement to limit to such, and the invention is applicable to situations where the legs have different geometries, physical dimensions and links.
While the key corner device 10 shown in FIG. 1 has a 90° bend, it is recognized that this is due to the fact that the typical garage door window has four sides, thereby necessitating this angle. For other window configurations, the angle of the key corner device is a matter of common knowledge of trigonometry. While the length of the two legs of the corner device as shown in the figure are equal, there is no need to limit the invention to such, and it is possible for either leg of the device to extend into the longitudinal receiving void to varying degrees, depending on the application requirements for corner rigidity and dimensional stability. The device will penetrate at least part way longitudinally and into the hollow voids.
Each leg of the key will have an interior 22 and exterior 24 wall with contiguous floor thereby creating a channel profile. In one embodiment, the interior and exterior walls will have a slight taper 36 , 38 at both peripheral ends 16 , 18 of the key device. This tapered arrangement facilitates insertion of each leg of the device into the mating hollow voids of the extruded frame. The floor 26 of each leg 12 , 14 has at least one aperture 28 , 30 disposed therein, typically positioned toward a peripheral end 16 , 18 of the key device. Each leg of the device additionally has at least one inwardly angled rib 32 , 34 positioned so as to intersect a vertical axis of the at least one aperture. The angle of the inwardly angled ribs 32 , 34 must be less than 90°, preferably from approximately 10° and 80° inclusive, more preferably from approximately 30° and 80° inclusive, and most preferably from 45° and 70° inclusive. Depending on the degree of stiffness required of the corner key, the inwardly angled ribs may be in connected relationship with an interior wall 22 along the entire length of the rib or only in connected relationship with a portion 34 a of the length of the rib. As illustrated with inwardly angled rib 32 , if the strength of the rib is sufficient, there may be no contact with either interior wall 22 along a length of the rib.
Insertion of a fastening device, e.g., screw 40 , through an exterior mitered frame of the framing system generates an axial downward force F y (i.e., Y-direction) as illustrated in FIGS. 3 & 4, permitting axial movement through an opening 46 in the window system and in colinear alignment with an aperture e.g., 30 of the key device. With further penetration of the fastening device into a channel 26 of the device, impinging contact is made with inwardly angled rib 34 which imparts a lateral deflecting force vector having at least a component normal to penetrating axial movement (F z or z-direction as illustrated in FIG. 4 for window framing member 44 and F x or x-direction as illustrated for window framing member 42 ). As the fastening device continues to migrate upwardly on the angled rib or ramp, additional vector forces normal to the axis of penetration are created which force the window frame to force the window frame in the direction of its opposed mitered corner end (not shown). Each ramp does the same behavior with the result being that each mitered corner is in tight communication resulting in an aesthetically pleasing visual appearance lacking in mitered corner gaps 48 , 50 .
Use of the corner key described above is but a first step in the ability to insert a window frame into a stamped opening in a garage door panel. The second step involves the ability of the installer to produce an essentially water-proof seal on an embossed surface where the difference between an elevated impression and a recessed plateau makes it difficult, if not close to impossible to effect an effective seal. As illustrated in FIG. 5, the window frame 60 into which a pane of glass will be sandwiched between (not shown) will include at least one hollow internal void 62 , having a pair of side walls 72 , 76 , a bottom and a top 74 , 78 . The frame will optionally have a laterally extending leg 68 with leg void 66 therein. When required, a reinforcing rib 94 can optionally be extruded therein thereby creating a secondary void 64 adjacent to the primary void 62 . In order to minimize any leakage on the interior side of the window frame, to which the glass is positioned adjacent thereto, a flexible seal 70 is coextruded with the window frame. Such coextrusions are known in the industry and typically involve a dual die head.
On the exterior side of the window frame, a second flexible seal is typically coextruded thereto on frame overlapping section 84 . In the Prior Art, this flexible seal was an outwardly facing seal 80 , and this arrangement is suitable for applications whereupon the sealing surface is essentially smooth. However, newer garage door panels are manufactured so as to mimic the look of wood and the metal door panels are embossed to attempt to reproduce the texture wood. It is known that attempting to effectively seal on an embossed surface using an outwardly facing seal which originates from the shelf is minimal.
Shifting the paradigm and focusing the efforts on sealing the window frame into the embossed garage door panel by sealing on an edge of the door panel using an inwardly facing seal 82 a, however, can achieve the desired results. As illustrated in FIG. 5, a portion of an embossed garage door panel 86 is shown in secured engagement with an inwardly facing seal 82 of the window frame 60 . By sealing on an edge, rather than an embossed exterior surface, an essentially leak-tight seal can be achieved which effects the goals of minimizing water ingress into the interior of the door panel, with attendant staining and rusting issues. Additionally, as illustrated in FIG. 5, the corner key 10 is insertable into a void 62 of the window frame 60 for initial engagement of the mitered corners. In a manner similar to that shown in FIG. 1, the key has two essentially parallel legs 22 , 24 extending essentially vertically from a base 26 .
While inwardly facing seal 82 a has been described so far as being coextruded from panel overlapping section 84 , there is no need to limit the attachment point to that location. In fact, in many applications, it is desirable to have this seal 82 b affixed to side wall 76 and extending in a similarly angled fashion toward overlapping section 84 as illustrated in FIG. 7 . The important consideration is that effective sealing engagement is made with the seal and an edge of the door panel and not with the embossed surface.
Thus, what has been described is both a window framing corner key and a window framing system utilizing the same, particularly suitable for use in garage door applications, although the application is not limited to such, but rather encompasses any situation wherein a window with associated frame needs to be assembled on-site and with minimal assistance. One of the aspects of the invention is the capitalization on an inwardly facing angled rib within a channel of the key device. As a fastening means, e.g., screw is pushed axially through a hole in a mitered window frame, and through an aperture in colinear alignment with the mitered window frame hole, a biasing force is generated normal to the axis of the fastening device which forces the window frame in tight physical alignment with the mitered corners, thereby promoting an aesthetically pleasing appearance with minimal opportunity for exterior weather elements to penetrate inside the door.
This invention has been described in detail with reference to specific embodiments thereof, including the respective best modes for carrying out each embodiment. It shall be understood that these illustrations are by way of example and not by way of limitation.
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The invention relates to window framing systems which use corner keys, and which seal against embossed surfaces, particularly for use in garage doors. The corner keys are insertable into hollow portions of extruded window frames and which preliminarily hold the window frame together prior to more permanent fastening within a garage door by a plurality of screws or even via a snap-fit arrangement. The angularity of at least two internal ribs of the corner key into which a fastener impinges thereupon, facilitates tightening engagement of each mitered window frame corner, leading to a superior appearance and preventing moisture from getting inside the window unit by the positioning of a sealing surface which seals on an edge of a door or panel.
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This application is a continuation of application Ser. No. 727,699, filed Apr. 26, 1985, now abandoned.
BACKGROUND OF THE INVENTION
The invention concerns an arrangement of a container on a vehicle so that it can pivot from an operating position around the longitudinal central axis of a bearing spindle into an installation position.
Containers installed on a vehicle usually serve to hold liquids or gases that are required for the operation of the vehicle. Thus, for example, lubricating oil, coolant, fuel, hydraulic oil or compressed air for a brake unit can be held in a container and removed from it when needed. Since such containers with the materials held in them are usually required as soon as the vehicle is assembled for it to function and be tested, they must often be installed even before the vehicle is painted and before other assembly procedures in the area of the container are completed. Moreover, depending on the location and size of the container, it may happen that it hinders or even blocks access to maintenance points, which is undesirable even after completion of the vehicle.
An arrangement of a container for the fuel of a starter motor of an internal combustion engine is shown in U.S. Pat. No. 2,833,365. This container is mounted on a cowl that is pivoted on the bearing of a motor hood of a tractor. The cowl, with the container, can be swung away from the machine into an installation position in order to install maintenance parts or it can be swung to the machine and fixed in place on the motor hood by a locking device to take up an operating position and remain there during the operation of the tractor.
Such an arrangement of a container assumes that it can be brought into the installation or operation positions by simple rotation, but this is not always possible in a number of design variants and is also not always desirable.
SUMMARY OF THE INVENTION
The task on which the invention is based is to improve the arrangement of the container in such a way that it can be brought to the vehicle in several positions in order to better fit the particular situation.
This task is solved according to the invention by the fact that the container is mounted so that it can be moved in the direction of the longitudinal central axis of the bearing spindle. In this way, the container can, when it pivots from the operating position to the installation position or viceversa, be displaced in another direction so that it undergoes as great a swinging motion as possible and does not collide with pipes, frame parts or brackets in this range of swing. Moreover, it can, without swinging, be brought into a position with respect to the vehicle in which access to maintenance parts is possible or other components can be installed. In particular, in this simple and inventive way, it is possible to bring the container, which is held in the operating position by means of a lock mechanism, into the installation position by lowering it out of the lock mechanism into another position to move it into the installation position. It is thus possible in a simple way to bring the container into the grasp of the lock mechanism, which need not necessarily consist of a special lock mechanism, but may consist entirely of sliding the container into a niche on the vehicle.
Especially in the case of containers with a large capacity that can normally be moved into the right position on the vehicle by a workman only with great difficulty due to their weight, even when empty or only partially full, it is quite advantageous if only for reasons of safety if the container is limited in its freedom of movement on the bearing along the longitudinal axis and the installation problems resulting from gravity are reduced when the container can be pushed toward or away from the contact surface of the vehicle according to the invention. For reasons of installation, it is particularly advantageous if the bearing can be turned to move the container so that a tool powered by compressed air or electricity, such as a wrench, can be used to perform the movement as quickly as possible and thus to shorten installation times, for which the invention provides the bearing with threads and the container engages the bearing by means of corresponding opposing threads. For reasons of safety, the invention also provides that the bearing also be able to be secured against turning.
According to a further suggestion of the invention, the above-described advantageous features can also be achieved if the container engages the bearing by means of a support that permits the movement so that the functions of storage of operating fluids and weight support can be separated. It is thus possible to select a suitable material, e.g., a plastic, for the container for storage of strongly aggressive hydraulic oil, while the support, on the strength of which high demands are placed, can be made of a suitably high-strength steel. In order to hold the container with the weight of its contents, the support is formed, according to the invention, in such a way that it is an angle with two legs, where one leg serves for connection with the container itself, in which case the leg holding the container may itself be designed as a case for the container, which is of great interest particularly in the case of forest work due to the danger from branches. This case can actually be formed so that it fulfills the legal prescriptions with respect to fire resistance for fuel containers.
The design according to the invention is such that the support has a trough and first and second end pieces through which the container is held in the trough. The first end piece engages the pivot axis by means of a guide element and the second end piece can be releasably fastened to the vehicle resulting in a secure attachment of the container to the vehicle.
A secure fastening of the container to the vehicle, according to the invention, is achieved by a lock mechanism consisting of two brackets with a U-shaped cross section that are fixed in a position on the vehicle to receive the container between their legs when the container is moved to the operational position.
In a highly functional way, the movement of the container from the operating position to the installation position is achieved according to the invention by the fact that the guide element is formed as a track with a guideway having a bracket with a threaded hole at its upper end, the bearing is in the form of a screw spindle and can be screwed into the threaded hole, the screw spindle is hung in brackets on the vehicle so that it can rotate and the lock mechanism consists of a carriage bolt that engages the guideway with its head end and is fastened to an angle bracket by means of a nut on its other end and the angle bracket is pivoted on a screw spindle bracket by means of a bolt whose longitudinal axis is coaxial with the longitudinal axis of the spindle.
The arrangement of a container according to the invention is especially useful when the container is an auxiliary fuel tank to the main fuel tank and is connected in series with it, in which case the auxiliary fuel tank can be filled through the main fuel tank and/or the main fuel tank can be emptied through the auxiliary fuel tank.
Some of the above features of the invention can be achieved without further ado by mounting the auxiliary tank below the main fuel tank, since, for example, when the main fuel tank is filled the fuel will run down into the auxiliary tank due to gravity alone and no additional fuel pump will be required.
The above and additional objects and advantages, and the details of construction of a preferred embodiment of the invention, will become apparent to those skilled in the art from a reading of the description of the preferred embodiment when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a tractor, cut away in the area of a rear wheel;
FIG. 2 is an enlarged side elevational view of an auxiliary fuel tank with a front and a rear frame member and a protective trough;
FIG. 3 is a schematic representation of a fuel injection circuit used on the tractor illustrated.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A vehicle illustrated in FIG. 1 is in the form of a tractor having an undercarriage 16 which is supported on front wheels 12 and rear wheels 14. A driver's cab 18 is mounted on the rear of the undercarriage. The undercarriage 16 consists essentially of an unshown front axle bracket which holds the floating front axle, a motor 20, a clutch housing 22 and a gearbox 24. Ballast weights 26 are fastened to the front axle bracket and above this is the front part of the hood 28, which contains a main fuel tank 164, which is only schematically shown in FIG. 3. Between this main fuel tank 164 and the driver's cab 18 is the motor 20, from which an exhaust pipe 32 extends upward through a hood 30. The driver's cab 18 is supported on the undercarriage 16 by several rubber mounts 34, of which only one is visible in FIG. 1. The rubber mount 34 shown is supported on a bracket 36 which, in turn, is bolted to the clutch housing. An axle housing 38, which holds an unshown rotating shaft for the corresponding rear wheel 14, is flanged to the corresponding side surface 42 of the gearbox 24 by a number of bolts 40 arranged in a circle at the rim of the axle housing. Finally, the attachment of an auxiliary fuel tank 46 which is held by a front bracket 48, a rear pivot structure 50 and a protective trough 52, should be noted in FIG. 1. Here, the front bracket 48 is bolted to the bracket 36 for the rubber mount 34, while the rear pivot structure 50 is held by the bolts 40 that fasten the axle housing 38 to the gearbox 24 so that the auxiliary fuel tank 46 extends on the left along the clutch housing 22 and part of the gearbox 24.
The front bracket 48 consists of a piece of flat steel bar 54 bent twice in opposing directions in the same plane with a short lower leg 56 and a long upper leg 58. The short leg is provided with a hole 60 for a bolt 62. At the end of the upper leg 58 is welded the bight 64 of a U-shaped bar 66. The legs 68 (only one of which is visable) grasp the auxiliary fuel container 46 on either side. The leg 68 on the left with respect to the direction of travel has a threaded hole 70 through which a bolt (not shown) can be screwed to hold a protective metal cover, also unshown. A bracket 72 extends upward from the upper leg 58 of the steel bar 54 and serves to fasten the front bracket 48 to the rubber mount by means of unshown bolts.
The rear pivot structure 50 is composed principally of an upper bracket 74, a lower bracket 76 and a positioning screw 78 that serves as a bearing and extends between the two of them. The upper bracket 74 has an approximately triangular plate 80 with two holes 82 through which the corresponding bolts 40 for fastening the axle housing 38 are secured. Welded at a right angle to this plate 80 is a flat steel bar 86 which extends in the direction of the front frame bracket 48 and has a U-shaped bar 84 welded to its forward end. This bar 84 grasps the auxiliary fuel tank 46 with two legs 88 (of which only one can be seen) in the same manner as the legs 68 of the bar 66. The leg 88 of bracket 84 that is away from the gearbox 24 is likewise bored to accept an unshown bolt for mounting the previously mentioned, but not illustrated, cover. The steel bar 86 has a hole 90 in the region of its end where it is welded to plate 80 through which the positioning screw 78 can freely pass, as will be described later. In the installed state, the side of plate 80 toward the gearbox 24 lies against the axle housing 38.
The lower bracket 76 is formed of a plate 92 that is bent away from the gearbox 24 at right angles at the top and bottom in order to form upper and lower pivot bearings 94 and 96 which in turn are pierced by holes 98 and 100, where the upper pivot bearing holds the positioning screw 78 and the lower pivot bearing 96 holds a bolt 102. The plate itself also has two holes 104 which are arranged like the holes 82 in plate 80 so that they align with the corresponding unshown mounting holes in the axle housing 38 and the corresponding bolts 40 for fastening the axle housing 38 can pass through them. The holes 82, 104 in the two plates 80, 92 all lie in the circle of holes for fastening the axle housing 38, so that the bolts 40 secure the axle housings to the gearbox and the plates to the axle housing. In the installed state, the side of plate 92 toward the gearbox 24 also lies against the axle housing 38. The two plates 80, 92 are mounted on the axle housing 38 so that when installed, the centers of hole 90 in the bar 86 of the upper bracket 74, hole 98 of the upper pivot bearing and hole 100 of the lower pivot bearing 96 lie in a vertical line.
The positioning screw 78 is a hex-head bolt with a continuous thread, the length of which is determined by the distance between the upper pivot bearing 94 and the flat steel plate 86 of the upper bracket 74. It should be at least long enough that when it is inserted through the hole 90 in the bar 86 of the upper bracket 74 and its head sits on this, its threaded shaft 110 protrudes beyond the underside of the upper pivot bearing 94 by at least the thickness of a self-locking nut 112 and a washer 114. An additional nut 116 is also screwed onto the threaded bolt 110 and lies above the upper pivot bearing 94 when installed.
The bolt 102 used in the lower pivot bearing 96 makes a pivoting connecting between an angle bracket 118 having two legs 122, 124 and the lower pivot bearing 96, wherein the bolt 102 passes through the one leg 122 and is held on the underside of the lower pivot bearing 96 by a self-locking nut 120. The other leg 124 of the angle bracket 118 also has a hole 126, in which a carriage bolt 128 that serves as a holding element is inserted.
The protective trough 52 is constructed in three pieces and consists of a left end piece 130, a right end piece 132 and a trough element 134 between them. Both end pieces have flanges to connect to the trough element 134 and are either spot welded or soldered at the overlapping points. An angle bracket 136 is attached to the left piece 130 and welded or screwed on and has a horizontal upper leg 138 that is parallel to the lower short leg 56 of the front bracket 48. A hole 140 is provided in the horizontal upper leg 138 in alignment with the hole 60 in the short lower leg 56 to accept the bolt 62. This bolt 62 passes through the hole 140 in the angle bracket 136 and screws into a nut 142 so that when another nut 144 is screwed on at the front bracket 48 it cannot turn. Nut 142 also prevents loss of bolt 62 if the protective trough 52 is not secured at the front bracket 48 by nut 44.
A rectangular tube 146 whose longitudinal axis is parallel to the longitudinal axis of the positioning screw 78 is welded to the right end part 132 and on the side 148 of the tube turned toward the positioning screw is a long slot 150 that extends the entire length of the tube 146. The rectangular tube 146 serves as a guide element and due to its shape can be called a track. Its upper end is closed by a bracket 154 that has a threaded hole 152 and extends between the rectangular tube 146 and the positioning screw 78, so that the positioning screw 78 can be screwed into the threaded hole 152. The lengthwise slot 150 forms a guideway in which slides the carriage bolt 128, whose rounded head cannot be seen in the interior of the rectangular tube 146 and the square section under the head, which is also not shown, comes to lie in the lengthwise slot 150 so that the angle bracket 118 can be clamped in place on the tube 146 by means of the carriage bolt 128 and a nut 106. However, it is also possible to use another sort of guide, such as a rod and clamp or an I-beam with an overlapping clutch. The carriage bolt 128 can be inserted into the slot 150 at the open lower end of the rectangular tube 146. When the carriage bolt 128 is loosened, the rectangular tube 146, and with it the protective trough 52, can be moved generally vertically relative to the rear pivot structure 50 by turning the positioning screw 78, which moves the auxiliary fuel tank 46 away from or toward the bars 66, 84 and thus brings it out of or into their grip.
The trough element 134 is made of bent sheet metal and is folded in the area of its upper end 156 to make a positive connection with the previously mentioned cover. Both the protective cover and the trough element 134 are made of about 3 mm thick sheet steel in order to provide effective protection for the auxiliary fuel tank 46 from forces from outside, for example impacts from branches when working in the woods. Considered schematically, the right end piece 132, the trough element 134 and the rectangular tube 146 form a two-legged support where one leg consists of the rectangular tube 146 and the right end piece 132 and grasps the positioning screw 78, while the other leg consists of the trough element 134.
The auxiliary fuel tank 46 is in the form of a plastic tank, the external form of which can be fitted to the particular local relationships in the area of the gearbox 24 and the clutch housing 22 and which can be positively grasped by the two brackets 66, 84 and the protective trough 52 when installed. In particular, it may have bulges and projections that permit installation of frame members or units that would normally extend into the area of the auxiliary fuel tank. It is provided with a connector 158 for a supply line, an air inlet/outlet connector 160 and a fuel line connector 162 which permit connection to an injection unit 190 shown schematically in FIG. 3 and to the main fuel tank 164.
The arrangement and the connection of the main fuel tank 164 with the auxiliary fuel tank 46 can be seen in FIG. 3. When installed, as shown, the main fuel tank 164 is mounted above the auxiliary fuel tank 46 and is provided in conventional fashion with a filler connection 168 and cap 166 on its upper side 170. The cap 166 has an air inlet/outlet valve 172 so that when fuel is removed from the main fuel tank 164 no vacuum can form therein and any overpressure that may form due, for example, to excessive solar radiation can be dissipated. At the height of the filler connection 168 is the opening of a return line 176 and a vent line 178 opens to the top of this main fuel tank 164.
The auxiliary fuel tank 46 has a raised portion 186 in its top 184 where a fuel line 180 coming from the bottom 182 of the main fuel tank opens into the feed line connection 158. The vent line 178 and the fuel line 192 running to the injection unit 190 connect to the auxiliary fuel tank by means of the vent line connector 160 and the fuel line connector 162 respectively. Depending on the design of the fuel tank 164, the vent line 178 could alternatively connect to the return line 176 before it enters the filler connection 168 instead of directly into the top of the main tank. The injection unit 190 is composed of a water separator 194 connected with the fuel line at the input side, and following that, a fuel pump 196, a fuel filter 198, an injection pump 200 and injectors 202, from which the unused fuel is returned to the main fuel tank by means of the return line 176.
The filling and emptying process for the main and auxiliary tanks is as follows. The fuel is first filled into the main tank 164 through the filler connection 168 and flows on directly to the auxiliary tank 46 through the feed line 180; the air in the latter tank can flow through the vent line 178 to the main fuel tank 164 and out into the atmosphere through the air inlet/outlet valve 172. Fuel can be added until the main fuel tank 164 is completely full. Even when the auxiliary fuel tank 46 is already full and fuel is flowing only into the main fuel tank 164, venting continues through the air inlet/outlet valve 172. When the motor 20 of the tractor 10 is started, the fuel pump 196 sucks fuel from the auxiliary tank 46 through the fuel line 192 and the water separator 194 and sends it through the fuel filter 198 to the injection pump, which feeds the injectors 202. Fuel that is not injected by the injectors into the combustion chambers of the motor 20 is returned to the main fuel tank 164 through the return line 176, from which it can be fed again into the injection cycle from the auxiliary tank 46. There accordingly occurs a constant circulation of fuel so that fuel is not allowed to stand for a long time in either fuel tank 46, 164.
The installation of the auxiliary fuel tank 46 is accomplished as follows. Assuming that the front bracket 48 is fastened to the bracket 36 for the rubber mount 34 of the driver's cab 18 and the rear pivot structure 50 is fastened to the axle housing 38, the protective trough 52 is placed in a position where the threaded hole 152 of bracket 154 is aligned with the hole 90 in the bar 86 of the upper bracket 74 and the hole 98 in the upper pivot bearing 94. Then the positioning screw 78 is inserted through the hole 90 in the flat bar 86 of the upper bracket 74, screwed into the threaded hole 152 and turned until it extends about 40 mm on the other side of the bracket 154. Then, the nut 116 is screwed onto the positioning screw 78 until it reaches the underside of the bracket 154 and the positioning screw 78 is inserted into the hole 98 of the upper pivot bearing 94 until its head 108 comes to rest on the upper side of the flat bar 86 of the upper bracket 74. Next, the washer 114 is brought into position against the underside of the upper pivot bearing 94 by the nut 112 so that the positioning screw 78 can still be turned without excessive force. In addition, the angle bracket 118 is attached by means of the carriage bolt 128 to the rectangular tube 146 and secured with nut 106 so that a relative motion between the bracket 188 and the rectangular tube 146 is possible and the angle bracket 118 is placed on the upper side of the lower pivot bearing 96 and secured with the bolt 102 and the self-locking nut 120. At this stage of installation, the entire protective trough 52 can still be pivoted around bolt 102 and the positioning screw 78 either into the operating position or into an installation position away from the gearbox 24 in which the region of the gearbox 24 and the clutch housing 22 that is covered by the auxiliary fuel tank can be painted.
When the protective trough 52 is pivoted into the installation position, the auxiliary fuel tank 46 can be set into it and pivoted back into the operating position alongside the gear box so that it lies underneath the two brackets 66, 84 and the two holes 60, 140 in the short lower leg 56 of the front frame member 48 and in the holding bracket 136 line up. The vent line 178, the feed line 180 and the fuel line 192 are flexible and long enough that they do not prevent the auxiliary fuel tank 46 from pivoting.
In order to bring the auxiliary fuel tank 46 into the grasp of the legs of the bars 66, 84, the positioning screw 78 is then turned, which may be done using a compressed-air powered wrench, so that the protective trough 52 is moved toward the bars 66, 84 by means of the rectangular tube 146, the bracket 154 and the screw connection of the threaded hole 152 with the positioning screw 78. During this movement, the bolt 62 engages the hole 60 in the short lower leg 56 of the front bracket 48, and the carriage bolt 128 slides along in the long slot 150. The positioning process ends when the auxiliary fuel tank 46 is firmly engaged by the bars 66, 84 and the positioning screw 78 can no longer be turned. In order to secure the auxiliary fuel tank 46 in the operating position finally, the bolt 62 is fastened in the front bracket 48 with the nut 144 and the protective trough is thus pressed upward so that the auxiliary fuel tank 46 is firmly located in the bar 66 of the front bracket 48 and the positioning screw 78 is locked by bringing the additional nut 116 onto the upper side of the upper pivot bearing 94 so that loosening and potential downward movement of the protective trough 52 is prevented. Finally, the carriage bolt 128 is tightened by means of the nut 106, so that the rectangular tube 146 and the protective trough 52 are firmly connected to the rear frame member 50. Depending on the working conditions, the previously mentioned protective cover can be attached by bolting it into the holes 70 in the brackets 66, 84.
Having thus described a preferred embodiment of the invention, various modifications thereto will become apparent to those skilled in the art and can be made without departing from the underlying principles of the invention. Therefore, the invention should not be limited to the preferred embodiment but only by spirit and scope of the following claims.
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A container such as a fuel tank pivotally mounted on a vehicle for movement between an operation position adjacent the vehicle and an assembly position remote from said vehicle. The pivotal movement is accomplished by having a support for the container threadably engaged with a screw spindle supported on the vehicle. The support can swing about the screw spindle and also be moved vertically along the axis of the screw spindle by rotating said screw spindle. The vertical movement serves to bring the container in or out of mesh with a lock mechanism which avoids a further pivot movement in the operation position.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of metal matrix composite materials and its subject is more particularly a method for manufacturing an insert formed of ceramic fibres in a metal matrix for reinforcing a metal part.
2. Description of the Related Art
Particularly in the aeronautics field, a constant aim is to optimize the strength of the parts for a minimal weight and footprint. Certain parts may now comprise an insert made of metal matrix composite material hereinafter called CMM, the part also being able to be monolithic. Such a composite material comprises a metal alloy matrix, for example of titanium alloy Ti, within which fibres extend, for example silicon carbide SiC ceramic fibres. Such fibres have a tensile strength that is markedly greater than that of titanium (typically 4000 MPa as opposed to 1000 MPa). It is therefore the fibres that absorb the forces, the metal alloy matrix performing a binder function with the rest of the part, and of protection and of isolation of the fibres, which must not come into contact with one another. Moreover, the ceramic fibres are erosion resistant but must necessarily be reinforced by metal.
These composite materials can be used in the manufacture of discs, of shafts, of cylinder bodies, of housings, of struts, such as reinforcements for monolithic parts such as blades, etc.
For compressor discs in a turbojet for example, a known reinforcement technique consists in inserting into the part a circular winding of coated fibres. One technique for manufacturing a CMM insert relies on the principle of winding coated yarns described in patent EP 1.726.677 filed in the name of Snecma. The insert is obtained from a plurality of coated yarns each comprising a ceramic fibre covered with a metal sheath. This type of yarn is called a coated yarn hereinafter. The manufacture comprises a step of winding a bundle or a bound layer of coated yarns around a part of revolution perpendicularly to the axis of the part. The insert is then subjected to a step of hot isostatic compression in a container. A container is a metal part blank into which a cavity has been machined for receiving the insert made of CMM material and which is then subjected to a hot isostatic compaction treatment. This treatment is called CIC hereinafter.
The parts described thus obtained are of circular type and are particularly suitable for not only compressor discs but for the production of circular parts such as shafts, cylinder bodies or housings.
Other mechanical parts require properties that differ from those presented by the circular parts. This is particularly the case of the connecting rods used for example in landing systems or of the structural parts such as engine suspensions, that are essentially of oblong shape. The function of these parts is to transmit a one-way traction and/or compression force. The reinforcement of these parts then requires inserts made of CMM that are rectilinear or substantially rectilinear in shape, at least in part. Specifically, the fibres must be oriented in the direction of the forces.
The manufacture of these inserts in an industrial manner and at least cost is awkward.
A method is known for manufacturing a mechanical part comprising at least one insert made of CMM material. The method comprises the manufacture of an insert blank by winding a bundle or a bound layer of coated yarns about an annular support of which a portion comprises a rectilinear or substantially rectilinear section.
The method described in patent FR 2.919.284 in the names of Snecma and Messier-Dowty develops this principle and then comprises the insertion of the insert blank hereinabove in a first metal container, the hot isostatic compaction of the first container, followed by the machining of the latter in order to form an insert element. After the manufacture of this insert element, the method for manufacturing a mechanical part comprises the following steps: insertion of the insert element into a second container, hot isostatic compaction of the second container and machining of the second container in order to form the desired mechanical part. The mechanical part thus obtained, for example a connecting rod, advantageously makes it possible to transmit one-way traction and/or compression forces in the direction of the ceramic fibres that have been incorporated therein.
Instead of passing through the intermediate step of compaction of the insert blank followed by cutting it into rectilinear insert elements, it would be possible to envisage cutting the annular coil forming the blank while keeping the coated yarns in a bundle. Patent application FR 2.925.896 teaches of the incorporation of this type of bundle in a rectilinear groove opening out at its ends.
This solution has several drawbacks which have an effect on the industrialization of these operations:
The coated yarns are lost in the non-straight portions. This loss is not insignificant because the half-produced coated yarn represents a considerable cost in the total cost of the part.
The winding, notably on oval shapes, induces stresses in the wound insert that risk being released which results in a deformation of the insert when cut.
These techniques require increasing the number of systems for keeping the coated yarns in line with the cutting zones.
Moreover, a technique based on coiling by winding a layer of previously assembled coated yarns is aimed essentially at the production of inserts with a cross section, perpendicular to the fibres, that is square or rectangular.
For certain applications, it would be desirable to have an insert with a section that is not square or rectangular in order to improve the absorption of forces between the composite insert and the rest of the structure of the part. Specifically, reinforcements with a cross section that is for example trapezoidal or elliptical would make it possible to prevent or at least to limit the leaps in stiffness and thus improve the mechanical strength of the transition zones.
For example, for elongate parts such as parts of landing gear, or connecting rods for suspending the engine comprising lateral attachments between their ends, a reinforcement in which the number of fibres is smaller along the edge of the part secured to the attachment allows a better transition of the forces at this attachment.
BRIEF SUMMARY OF THE INVENTION
The objective of the present invention is to perfect a technique for producing inserts that is of reduced cost and is easy to industrialize.
A further object of the invention is a manufacturing technique that allows the production of inserts that are called shaped, that is to say of which the cross section may be different from the square or rectangular shape.
This object is achieved with a method for manufacturing an insert of elongate shape designed to be incorporated by CIC into a metal container, comprising coated yarns bound together, the said coated yarns being formed of metal-coated ceramic fibres, characterized in that it comprises a step consisting in placing the coated yarns side by side in a bundle consisting of a plurality of layers of coated yarns, in pulling the bundle of coated yarns through a shaping element so as to compact it transversely while forming it with a determined cross section by the shaping element, and in placing straps transversely clamping the bundle, downstream of the shaping element.
Preferably, the bundle is shaped from coated yarns that are unwound from yarn reels.
The bundle of yarns, before it passes through the shaping element, has interstitial spaces resulting from the circular section of the coated yarns. The shaping element is dimensioned so as to reduce the spreading of the yarns and the interstitial spaces while giving the bundle the desired shape. The problem of industrialization and the shaping of the bundle of yarns is thus simply resolved. The passageway cross section of the shaping element is chosen freely depending on the shape, in the transverse plane, that is desired for the insert.
According to one embodiment, the shaping element comprises at least two rotary rollers, the axes of the two rollers being oriented perpendicularly to the direction of travel of the coated yarns. In order to complete the contour, the shaping element notably comprises lateral supports fixed between the rollers. The shaping element may also comprise a plurality of rollers forming the contour of the passageway cross section. The function of the rollers is to reduce the friction on the bundle of coated yarns while accompanying its movement. Fixed elements are also suitable to the extent in which the friction of the fibres is reduced.
It is thus possible to shape a shaping element of which the passageway cross section is polygonal with sides that are rectilinear or curved or else of oval or circular cross section.
In order to ease the guidance of the fibres to the shaping element and subsequently to keep them together in the bundle, a metal sheet, also called foil, is advantageously interposed between the coated yarns of the bundle and at least one portion of the sides of the shaping element.
The assembly of the coated yarns is maintained by collars or rings placed along the insert downstream of its passage through the shaping element. The rings are formed for example of a metal sheet forming a strap with which the bundle is surrounded tightly and of which the ends are welded after they are folded over one another.
The bundle of coated yarns is then cut to the desired length corresponding to the length of the insert to be placed in the metal container. In order to prevent the spreading of the coated yarns at ends of the insert, making it difficult to handle the latter and to place it in the container, it is wise to saw the bundle through a clamping ring because the portions of ring obtained are placed at the end and provide the clamping of the bundle.
According to one embodiment of the method, the coated yarns, before they are combined into a bundle, are guided in their movement towards the shaping element so as to form subassemblies or elementary bundles. These may be layers that are superposed on one another to form the said bundle. An elementary bundle is formed by simultaneously unwinding the coated yarns of the subassembly from separate reels. For example it is possible thus to form a stack of layers of rectilinear coated yarns obtained by flatly juxtaposing a determined number of coated yarns until a determined number of layers is obtained. More particularly, a first layer is placed on a bearing surface, notably comprising a metal sheet, and the last layer is overlapped through the shaping element. Instead of layers, the elementary bundles may have any cross-sectional shape.
According to another embodiment, the coated yarns are combined into elementary bundles in a plurality of guides, channels or tubes that are placed so as to converge on the passageway cross section of the shaping element.
The method of the invention is a step of a method for manufacturing a metal part comprising the incorporation of the insert and carried out in a metal container and the hot isostatic compaction of the assembly, as described for example in patent application FR2933422 or application FR2933423 in the name of Messier Dowty.
According to this type of method,
at least one housing for an insert is machined in a metal body forming the container, the said insert is placed in the housing, a metal cover is placed on the body so as to cover the insert, the cover is welded onto the metal body, the assembly of the metal body with the cover is welded by hot isostatic compression and the said treated assembly is machined to obtain the said part.
The solution of the invention allows the incorporation of the insert in a container, immediately downstream of the shaping element. For example, the container may comprise a longitudinal through-housing into which the bundle of coated yarns is slipped. In this case, it is possible to dispense with the retaining rings or even with the longitudinal foils.
The invention also relates to a part of elongate shape comprising at least one fibrous reinforcement in the longitudinal direction, the said part being obtained according to the previous method, of which the cross section of the reinforcement has a shape that is not rectangular or square, such as a trapezoidal or oval shape.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The invention will be better understood and other objects, details, features and advantages of the latter will appear more clearly in the course of the following detailed explanatory description of embodiments of the invention that are given as purely illustrative and non-limiting examples with reference to the appended schematic drawings.
In these drawings
FIG. 1 shows the various steps 1 a to 1 d for manufacturing a part of elongate shape according to the prior art;
FIG. 2 represents a side view of an installation for manufacturing a rectilinear insert according to the invention;
FIG. 3 shows the installation of FIG. 2 in front view;
FIG. 4 shows an insert manufactured according to the invention;
FIG. 5 shows a shaping die variant.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 a , extracted from patent application FR 2.919.284 in the names of Snecma and of Messier-Dowty, shows a container 1 with a main body 4 of elongate shape designed to form a connecting rod of a landing gear for example. A groove 41 has been machined on each of the two faces of the body 4 . This groove allows the housing of an insert 3 which comprises two rectilinear portions which may or may not be parallel with one another joined together at the ends by a circularly arcuate portion. The inserts are of the type with ceramic fibres coated with metal such as titanium.
The grooves and the inserts are of matching shapes so that the insert is fitted without clearance in the groove. Note that the groove in the container and the tenon on the cover must be assembled perfectly in order to prevent the fibres, that have a very small diameter, of the order of 0.25 mm, from escaping during the hot isostatic compaction. Two covers 5 are provided with a protruding portion forming a tenon 51 and cover the faces of the body 4 . The tenon rests on the insert housed in the groove and plugs the latter. The cover 5 is welded, for example by electron beam, to the body 4 ensuring a vacuum inside the container.
The container can be seen in FIG. 1 b ; it is partly cut away in order to show the inserts. The container is then placed in an appropriate enclosure in order to sustain therein a hot isostatic compaction treatment. The object of this treatment is to secure to one another the container, its cover and the layers of coated yarns and to form a monolithic part. The cross section of the container of FIG. 1 c shows that the edges 42 of the groove 41 are bevelled so as to arrange a clearance with the portion of the cover 5 that is adjacent to the tenon 51 . During the hot isostatic compaction operation, pressure is exerted in the direction perpendicular to the surface of the cover generating the collapse of the covers.
The heat and the pressure, respectively of the order of 1000° C. and 1000 bar, allow the metal of the matrix to fill the empty spaces between the coated yarns forming the insert. The volume of the insert reduces by approximately 23%. The tenon is thus moved in the direction of the bottom of the groove and the clearance on either side of the tenon is absorbed. At the end of the process, the metal portions are welded together by diffusion and the insert of coated yarns is compacted; the part is thus reinforced by the coated yarns trapped in the solid block.
FIG. 1 d shows the part blank obtained with two inserts that can be seen transparently. The blank is then machined so as to obtain the desired part. The ceramic fibres are thus incorporated into the zones of the part that transmit the tension and compression forces.
The inserts used according to the teaching of this patent FR 2 919 283 are of annular shape but as has been described in patent application FR 2 919 284, they can be formed of elongate bar-shaped elements. In the latter case, the inserts are incorporated, according to the technique explained in this document, in the container after having been compacted beforehand.
The production of the rectilinear inserts according to FR 2 919 284 comprises the winding of the coated yarns around a coiling device of annular shape with rectilinear portions. The shape may be oblong, with rectilinear portions, or else polygonal in which the sides of the polygon form the rectilinear portions.
After formation of the winding of the coated yarn or yarns in a collar, the turns of the collar are immobilized with respect to one another by means of welded metal straps. The assembly is incorporated into a container and sustains a hot isostatic compaction treatment according to the technique described above. From the semi-finished part, compact inserts of elongate shape are machined that are incorporated individually into containers for the manufacture of parts with ceramic fibre reinforcements.
According to the invention, the production of the inserts is simplified by forming inserts of elongate shape consisting directly of coated yarns 13 assembled like bunches or bundles.
With reference to FIG. 2 , a typical installation allowing the implementation of the method of the invention comprises a spool 10 supporting a plurality of rows of reels 12 onto which the coated yarns 13 are wound. The coated yarns are pulled from their respective reels in a system of channelled slides 14 on which they converge. The system brings the coated yarns together in a bundle. At this stage, the bundle is relatively spread. The coated yarns are advantageously placed in a plurality of subassemblies or layers of juxtaposed coated yarns 13 that are parallel with one another.
A foil or a metal sheet 16 , which is thin, is placed on the bottom of the tool in the form of a gutter 14 . The metal of the foil is preferably the same as that of the metal part for which the insert is intended. It is for example a titanium alloy.
The coated yarns rest on the lower foil 16 . They are stacked on one another for example in layers. The width of the layers, the number of the coated yarns that form the layers, may vary from the base to the upper layer. For example, the bundle may have a trapezoidal shape in cross section. A foil 15 is placed on the top of the stack of layers of coated yarns.
The number of yarns in the layers is not limiting; it depends on the part to be manufactured; the representation of the figures is simply an indication; the diameter of the yarns is not on the same scale as that of the gutter. The coated yarns are juxtaposed in the layers with no looseness or with a minimum of looseness between the yarns. At this stage the coated yarns have sustained no transverse stress.
Instead of layers, it is possible to have the yarns in subassemblies formed of elementary bundles that are brought together in a single bundle 13 f.
The bundle 13 f of coated yarns is thus guided through the shaping element 17 where it sustains a transverse compression. The shaping element in this instance comprises two rollers 17 g with horizontal axes. As can be seen in FIG. 3 , the rollers are rotatably mounted in a frame 17 b . The spacing between the two rollers may be adjusted by vertical movement of their support. Appropriate motors, not shown, optionally rotate them. The contour of the passageway cross section of the shaping element is supplemented by two fixed supports forming sliders 171 , placed laterally on either side of the bundle. The supports 171 are secured to the frame 17 b . According to this example, they are inclined relative to the vertical. The contour of the passageway cross section of the shaping element is therefore trapezoidal.
Passing through the shaping element, the bundle of coated yarns takes the form of the shaping element, in this instance trapezoidal. At the outlet of the shaping element, it is therefore necessary to keep the bundle in the given shape.
Small foils 18 forming straps are then put in place to maintain the assembly, running round the bundle of coated yarns.
The bundle is thus pulled through the shaping element by means of a pulling tool using pincers for example.
The insert 13 i is shown finished in FIG. 4 .
It is understood that the present method is not limited to the production of inserts of square, rectangular or trapezoidal cross section. Many shapes are within the scope of those skilled in the art. It is possible to have in the shaping element a plurality of rolls or rollers around the bundle in order to give it a polygonal shape. The sides of the polygon may be straight but they may also be curved. It is sufficient to choose a convenient profile.
The shape and the transverse dimensions of the shaping element may be defined by the geometry and the dimensions of the insert that it is desired to use. In this case, the number of coated yarns necessary to form the insert is determined. Conversely, there may be a need for an insert with a determined number of coated yarns. In this case, the passageway cross section of the shaping element is adjusted so that it can contain the desired number of coated yarns at the outlet.
It is advantageous to have guiding elements that can be adjusted in position transversely in order to allow, in the retracted position, the bundle of coated yarns to be put in place before they are clamped onto the bundle. Adjusting the spacing of the rollers and of the metal supports makes it possible to adjust the cross section of the passageway and that in which the bundle of coated yarns comes out.
It may also be advantageous to place vibrating elements helping the coated yarns to consolidate in the bundle.
FIG. 5 shows another non-limiting exemplary embodiment of the shaping element. It is formed of two rollers 17 ′ g with horizontal axes and with a curved profile interacting with two rollers 17 ′ 1 with vertical axes and a straight profile.
The present method also allows the production of a plurality of inserts simultaneously; the inserts are cut in the length of the bundle thus obtained.
Once the insert is finished, such as the one shown in FIG. 4 , it is incorporated into a metal container according to the method known and described above to form a metal part. In comparison with the method of the prior art illustrated by FIG. 1 for producing an elongate part, rectilinear grooves are produced in which two rectilinear inserts are placed on each face of the container. For the rest, the method is the same.
According to a particular method for producing the metal part, one of the foils is used both as a support and as a cover of the metal container in which the insert is placed. The cover is welded onto the container while producing a vacuum in the part before the hot isostatic compaction treatment.
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A method of manufacturing an elongate insert configured to be integrated by CIC in a metal container, including coated yarns bonded together, the coated yarns being formed from metal-coated ceramic fibers. The method includes placing the coated yarns side by side in a bundle and pulling the fiber bundle through a shaping element so as to compact the fiber bundle transversely while forming the fiber bundle so as to have a defined cross section. A metal part incorporating a fibrous insert can be manufactured by the CIC technique.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a network that implements Distributed Hash Table (DHT) and, more particularly, but not exclusively to classify the nodes into different roles for the purpose of routing packet and storing data.
[0003] 2. Description of Related Art
[0004] Identity:
[0005] The node ID in DHT network is usually randomly generated, for example, using the SHA1 hash value of the node's RSA public key, which make the ID evenly distributed in the DHT namespace.
[0006] The data ID is generated based on the hash value of the key part of its key-value pair. The same SHA1 hash function for node ID generation is used, so it has the same bit-length as the node ID, and both ID's are put into a single DHT namespace.
[0007] Routing:
[0008] When a node N receive a packet P with destination node ID of T, and N find that, of all the neighbor nodes that N is keeping track of, the closest node to T is S, then N just forwards P to S, which will perform the same logic and eventually the packet is routed to its destination of node T.
[0009] Storage:
[0010] In the DHT network, the node ID and data ID shares the same namespace (for example, a 128-bit number). For a key-value pair data of ID D, it's stored at the node of ID R, where R is the numerically closest neighbor to D. Node R is then called the Rood node for data D, i.e. R:=Root(D).
[0011] Distance by XOR Values
[0012] The way each node in DHT keeps track of neighboring nodes is given that XOR of node ID's numeric values is used as the distance between nodes. An example (and popular) algorithm is Kademlia:
[0013] Please refer to FIG. 1 which is an example of a distance tree with XOR property. As shown in the figure, number N here may be number 6 for simplicity. Thus, the node A may have a node ID 000000 which denotes from bit 0 to bit 6 (from bit 0 , left hand side branch may be 0 and right hand side may be 1), and the node B aside node A may have a node ID 000001 which also denotes from bit 0 to bit 6 . After XOR procedure, the distance between node A and node B is 000001. Also, the node C may have a node ID 000011 which denotes from bit 0 to bit 6 . After XOR procedure, the distance between node A and node C is 000011, and the distance between node B and node C is 000010. Therefore, by using XOR of node ID's numeric values the distance between nodes can be known.
SUMMARY OF THE INVENTION
[0014] A method of classifying nodes for routing packet and storing data is disclosed, comprising: defining a plurality of nodes into a plurality of kinds of node groups in a network: a server node group, a peer node group and a client node group, wherein the nodes in the server node group are used for packet routing and data storage, and the nodes in the peer node group are used for packet routing; and dividing a plurality of data IDs into a plurality of types: a first type and a second type, wherein the data IDs in the first type are closer to the server node group than the peer node group, and farthest to the client node group, and the data IDs in the second type are closer to the peer node group than the server node group, and farthest to the client node group.
[0015] A system for routing packet and storing data is further provided. The system comprises a plurality of node groups, comprising: a server node group, a peer node group and a client node group, wherein the nodes in the server node group are used for packet routing and data storage, and the nodes in the peer node group are used for packet routing; and two types, comprising: a first type and a second type, wherein the data IDs in the first type are closer to the server node group than the peer node group, and farthest to the client node group, and the data IDs in the second type are closer to the peer node group than the server node group, and farthest to the client node group.
[0016] A network with a peer-to-peer protocol for routing packet and storing data is further provided. The network with a peer-to-peer protocol comprises a transceiver to send and receive data over the network; and a processor that is configured to: define a plurality of nodes into a plurality of kinds of node groups in a network: a server node group, a peer node group and a client node group, wherein the nodes in the server node group are used for packet routing and data storage, and the nodes in the peer node group are used for packet routing, and wherein the client node group is closer to the server node group than the peer node group; and divide a plurality of data IDs into a plurality of types: a first type and a second type, wherein the data IDs in the first type are closer to the server node group than the peer node group, and farthest to the client node group, and the data IDs in the second type are closer to the peer node group than the server node group, and farthest to the client node group.
[0017] With these and other objects, advantages, and features of the invention that may become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the detailed description of the invention, the embodiments and to the several drawings herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The exemplary embodiment(s) of the present invention will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the invention, which, however, should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding only.
[0019] FIG. 1 is an example for XOR distance tree.
[0020] FIG. 2 is a system diagram of one embodiment of an environment in which the invention may be practiced.
[0021] FIG. 3 is a schematic view illustrating an embodiment of a distance graph of various roles according to the present invention.
[0022] FIG. 4 is a schematic view illustrating another embodiment of a distance graph of various roles according to the present invention.
[0023] FIG. 5 illustrates operation of certain aspects of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, specific exemplary embodiments by which the invention may be practiced. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Among other things, the present invention may be embodied as methods or devices. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. The following detailed description is, therefore, not to be taken in a limiting sense.
[0025] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrase “in one embodiment” as used herein does not necessarily refer to the same embodiment, though it may. Furthermore, the phrase “in another embodiment” as used herein does not necessarily refer to a different embodiment, although it may. Thus, as described below, various embodiments of the invention may be readily combined, without departing from the scope or spirit of the invention.
[0026] In addition, as used herein, the term “or” is an inclusive “or” operator, and is equivalent to the term “and/or,” unless the context clearly dictates otherwise. The term “based on” is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of “a,” “an,” and “the” include plural references. The meaning of “in” includes “in” and “on.”
[0027] Illustrative Operating Environment
[0028] FIG. 2 shows components of one embodiment of an environment in which the invention may be practiced. Not all the components may be required to practice the invention, and variations in the arrangement and type of the components may be made without departing from the spirit or scope of the invention. As shown, system 200 of FIG. 2 includes networks that enable communication between client and network devices or servers. A network 205 may comprise one or more local area networks (“LANs”) and/or wide area networks (“WANs”). A wireless network 210 may comprise LANs, WANs, telephony networks, or the like. System 200 also includes a general purpose peer device 201 , mobile client devices 202 - 204 , and content server 206 .
[0029] Generally, mobile devices 202 - 204 may include virtually any portable computing device capable of receiving and sending a message over a network, such as network 205 , wireless network 210 , or the like. Mobile devices 202 - 204 may also be described generally as client devices that are configured to be portable. Thus, mobile devices 202 - 204 may include virtually any portable computing device capable of connecting to another computing device and receiving information. Such devices include portable devices such as, cellular telephones, smart phones, display pagers, radio frequency (RF) devices, infrared (IR) devices, Personal Digital Assistants (PDAs), handheld computers, laptop computers, wearable computers, tablet computers, integrated devices combining one or more of the preceding devices, and the like. As such, mobile devices 202 - 204 typically range widely in terms of capabilities and features. For example, a cell phone may have a numeric keypad and a few lines of monochrome LCD display on which only text may be displayed. Such mobile devices may include a messaging client that enables a user to send and receive limited size text messages, but may not enable a user to send or receive long messages, graphics, images, or other content.
[0030] In another example, a web-enabled mobile device may have a touch sensitive screen, a stylus, and several lines of color LCD display in which both text and graphics may be displayed. A web-enabled mobile device may include a messaging client and a browser application that is configured to receive and to send web pages, web-based messages, and the like. The browser application may be configured to receive and display graphics, text, multimedia, and the like, employing virtually any web based language, including a wireless application protocol messages (WAP), and the like. In one embodiment, the browser application is enabled to employ Handheld Device Markup Language (HDML), Wireless Markup Language (WML), WMLScript, JavaScript, Standard Generalized Markup Language (SMGL), HyperText Markup Language (HTML), extensible Markup Language (XML), and the like, to display and send a message. In one embodiment, a user of the mobile device may employ the browser application to exchange text messages that include search queries and search results. A user may also employ a browser application to access additional search result content that is identified in one or more text messages.
[0031] Peer device 201 may include virtually any computing device capable of communicating over a network to send and receive information, including search query information, location information, social networking information, or the like. The set of such devices may include devices that typically connect using a wired or wireless communications medium such as personal computers, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, or the like. Peer device 201 may include a messaging system and/or interface for sending or receiving text messages with mobile devices 202 - 204 or other client devices.
[0032] Wireless network 210 is configured to couple mobile devices 202 - 204 and its components with network 205 . Wireless network 210 may include any of a variety of wireless sub-networks that may further overlay stand-alone ad-hoc networks, and the like, to provide an infrastructure-oriented connection for mobile devices 202 - 204 . Such sub-networks may include cellular networks, mesh networks, Wireless LAN (WLAN) networks, and the like.
[0033] Network 205 is enabled to employ any form of computer readable media for communicating information from one electronic device to another. Also, network 205 can include the Internet in addition to local area networks (LANs), wide area networks (WANs), direct connections, such as through a universal serial bus (USB) port, other forms of computer-readable media, or any combination thereof. On an interconnected set of LANs, including those based on differing architectures and protocols, a router acts as a link between LANs, enabling messages to be sent from one to another. Also, communication links within LANs typically include twisted wire pair or coaxial cable, while communication links between networks may utilize analog telephone lines, full or fractional dedicated digital lines including T1, T2, T3, and T4, Integrated Services Digital Networks (ISDNs), Digital Subscriber Lines (DSLs), wireless links including satellite links, or other communications links known to those skilled in the art. Furthermore, remote computers and other related electronic devices could be remotely connected to either LANs or WANs via a modem and temporary telephone link. In essence, network 205 includes any communication method by which information may travel between content server 206 , peer device 201 , and other computing devices.
[0034] Content server 206 represents a variety of content and/or other data that may useable on mobile devices 202 - 204 and/or on peer device 201 . Such content may include text content, web content, audio content, video content, FTP data, or the like. Data services may include, but are not limited to SMS, IM services, email services, services, web services, third-party services, audio services, video services, VOIP services, calendaring services, photo services, or the like. Devices that may operate as content server 206 include personal computers desktop computers, multiprocessor systems, microprocessor-based or programmable consumer electronics, network PCs, servers, and the like.
[0035] Generalized Implementation
[0036] As noted herein, exemplary embodiments are directed to quality of service in a structured peer-to-peer network. In a network that implements Distributed Hash Table (DHT), a node in the network can be used to store both routing information and key-value pair data, based on both node ID and data ID. Each node keeps track of a set of neighboring nodes, such that any node in the network can find all other nodes in the network through relays without keeping information of every node in the network.
[0037] Not all nodes in the DHT network are created equal in the present invention. For example, mobile devices, with limited bandwidth & battery, might prefer not want to route traffic in the network, whereas untrusted/unreliable nodes should not store important data. In order to keep all nodes and data within one single namespace while being able to prioritize the routing and storage preferences, each node in the DHT network is assigned different roles based on its node ID, without any change to the DHT algorithm that make the routing & storage logic sound.
[0038] In one embodiment, for given nodes are defined 3 roles in the DHT network: (1) Server node, which prefers to do both packet routing and data storage functionalities. (2) Peer node, which prefers to do only packet routing, but not data storage, functionalities. (3) Client node, which prefers neither packet routing nor data storage.
[0039] Also, to implement the above 3 different node roles, here's the requirements:
[0040] (1) For data storage, it's desired that the data ID is always closer to some specific set of node ID than the rest of nodes, so that data identified by data ID can be stored at the “Root” node whose node ID is the one with the closest numeric distance to data ID than the rest of nodes. Furthermore, data IDs can be divided into two types: (i) S-Data ID: those who are closer to Server nodes than Peer nodes, and farthest to Client nodes. (ii) P-Data ID: those who are closer to Peer nodes than Server nodes, and farthest to Client nodes.
[0041] Here's the above requirements in mathematical forms: (d(x,y) represents the distance/closeness between ID x and ID y, and the value of distance is represented in Hexadecimal). Also, please refer to FIG. 4 which is a schematic view illustrating an embodiment of a distance graph of various roles according to the present invention.
[0042] Distance Requirement for Storage Preference:
[0000] d ( S .DATA, Server)< d ( S .DATA, Peer)< d ( S .DATA, Client) (I)
[0000] d ( P .DATA, Peer)< d ( P .DATA, Server)< d ( P .DATA, Client) (II)
[0043] (2) For packet routing, it's desired that a set of node IDs (Client) are always closer to some specific set of node ID (Server) than the rest of nodes (Peer). This means Client nodes only need to keep connection with its closest Server nodes, which will receive packets from the rest of the system that's destined for Client nodes. This would spare Client node from packet routing responsibilities.
[0044] Here's the above requirements in mathematical forms: (d(x,y) represents the distance/closeness between ID x and ID y). Also, please refer to FIG. 3 which is a schematic view illustrating an embodiment of a distance graph of various roles according to the present invention.
[0045] Distance Requirement for Routing Preference:
[0000] d (Peer, Server)< d (Client, Server)< d (Client, Peer)
[0046] Further, given a node ID or data ID with numeric value, and given that the “closeness” of ID is calculated via mathematic XOR operator. Prefix can be added to the ID to satisfy the 2 requirements above. Here's an embodiment of pretending some calculated bit values in front of the IDs for implementing the design:
[0000]
[0047] As shown in the embodiment, Server, Peer, Client, S.DATA and P.DATA may be divided into 2 groups by Data Bit. Server, Peer and Client may be in one group (with Data Bit as 0), and S.DATA and P.DATA may be in the other group (with Data Bit as 1). In addition, by using Client Bit and Peer Bit, Server, Peer and Client can be keeping in their positions (virtual), respectively in one group. Similarly, through Peer Bit, S.DATA and P.DATA can be kept in their positions (virtual), respectively in the other group. Therefore, by using XOR of node ID's numeric values the distance between all the nodes can be known. The smaller result after XOR procedure between two nodes, the closer they are.
[0048] Please see the following XOR results according to the prefix embodiment above:
[0000]
XOR
Server
Peer
Client
Distance
(0x9)
(0xB)
(0xC)
S.DATA (0x0)
0x9
0xB
0xC
P.DATA (0x2)
0xB
0x9
0xE
[0049] Distance Requirement for Storage Preference:
[0000]
d
(
S
.
DATA
,
Server
)
0
×
9
<
<
d
(
S
.
DATA
,
Peer
)
0
×
B
<
<
d
(
S
.
DATA
,
Client
)
0
×
C
(
I
)
d
(
P
.
DATA
,
Peer
)
0
×
9
<
<
d
(
P
.
DATA
,
Peer
)
0
×
B
<
<
d
(
P
.
DATA
,
Client
)
0
×
E
(
II
)
[0050] Also, by Routing Bit, the routing distances of Server, Peer and Client can be calculated via mathematic XOR operator. Please see the results below.
[0000]
XOR
Server
Peer
Client
Distance
(0x9)
(0xB)
(0xC)
Server
(0x9)
0x0
0x2
0x5
Peer
(0xB)
0x2
0x0
0x7
Client
(0xC)
0x5
0x7
0x0
[0051] Distance Requirement for Routing Preference:
[0000]
d
(
Peer
,
Server
)
0
×
2
<
<
d
(
Client
,
Server
)
0
×
5
<
<
d
(
Client
,
Peer
)
0
×
7
[0052] Please refer to FIG. 4 which is a schematic view illustrating another embodiment of a distance graph of various roles according to the present invention. As shown in the figure, A, B, C, X 1 , X 2 , X 3 , Y 1 , Y 2 , and Y 3 denotes the distances between the nodes, respectively. Based on previous discussion, the distance between Server, Peer, Client, S.DATA and P.DATA will be shown as the following:
[0000] X1<X2<X3, Y1<Y2<Y3, and C<B<A.
[0053] FIG. 5 illustrates operation of certain aspects of the invention. The method of classifying nodes for routing packet and storing data comprises the following steps:
[0054] (S 501 ) defining a plurality of nodes into three kinds of node groups in a network: a server node group, a peer node group and a client node group, wherein the nodes in the server node group are used for packet routing and data storage, the nodes in the peer node group are used for packet routing but not for data storage, and the nodes in the client node group are not used for packet routing and data storage; and
[0055] (S 502 ) dividing a plurality of data IDs into two types: a first type and a second type, wherein the data IDs in the first type are closer to the server node group than the peer node group, and farthest to the client node group, and the data IDs in the second type are closer to the peer node group than the server node group, and farthest to the client node group.
[0056] The detailed description and embodiments of method according to this invention are given above, and so unnecessary details are not given here.
[0057] In summary, here are the advantages of the invention over both the pure peer-to-peer mode and traditional Client-Server architecture:
[0058] 1. Simplicity: there's no need to change the existing proximity-based DHT algorithms for grouping the nodes, as well as data, into multiple classes and provision them with various functionalities based on class type. For this invention to be adopted by any XOR-based algorithm, the only implementation change is to add prefix digits in the node or data ID, in order to classify them into multiple categories, and provide different level of quality of service over them.
[0059] 2. Zero-Configuration: this invention allows automatic provisioning of service, like routing and storage, without any configuration changes of the network. For a given node to provide routing or storage service, all it needs to do is to announce a new Node ID with custom prefixes in this invention, and the whole network would be able to find and use its service immediately.
[0060] 3. Efficient usage of resource: for devices with limited capacity like cellular phones or dispensable sensors, they can be classified as Client group role in this invention, and be spared from the responsibility of routing or storage in a peer-to-peer network. This would greatly reduce their network bandwidth usage, and increase their battery life and power efficiency.
[0061] 4. Faster network response: nodes in the network can be classified according to this invention, so that only those with high bandwidth and/or low latency are allowed to provide network relay service in a structured peer-to-peer network. This would improve the response time of the connection, and increase the throughput of the overall network.
[0062] 5. Reliable Storage: by using algorithm in this invention, the designated group is preferred as the root storage for specific data. For example, S.DATA would be stored at Server if available, and P.DATA at Peer. An application of this is that, data that need reliable storage at Server can be classified as S.DATA, whereas transient data can be stored at Peer node that may not always be available.
[0063] While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from this invention and its broader aspects. Therefore, the appended claims are intended to encompass within their scope of all such changes and modifications as are within the true spirit and scope of the exemplary embodiment(s) of the present invention.
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This present invention is to classify the nodes into different roles for the purpose of routing packet and storing data. This is needed because each node in the Distributed Hash Table (DHT) network may have various capacities in terms of network bandwidth and disk storage. That is to say, this invention is focusing on assigning distinct functional roles (Server/Peer/Client) to nodes in the network based on the prior art (algorithm Kademlia). By using XOR of node ID's numeric values the distance between all the nodes can be known.
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BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to a system for pumping oil from a well, and more particularly to an artificial lifting system in which a composite tubing string is used for operating a reciprocating pump at the foot of the well and for transporting oil to the head of the well.
2. Background Art
Artificial lifting systems of the type commonly employed in the hydrocarbon production industry normally have a carbon steel tubing string which runs from a wellhead at the surface of the earth downwardly through a well bore to an oil bearing formation. The tube is connected at its lower end to a carbon steel or alloy pump, and the pump has a reciprocating plunger for extracting oil from the formation and transporting oil upwardly through the steel tube to the wellhead.
More particularly, the pump plunger is actuated in a reciprocating manner by a rod string which extends downwardly through the tubing string. The rod string typically is made of carbon steel or fiberglass, and is vertically lifted by a pump drive unit which is located at the wellhead and aligned directly over the well bore. Fluids which are extracted by the pump are ported into the annular space between the rod string and the tubing string. The fluids then are forced to the surface and discharged through a pumping tee to surface flow lines which, in turn, are connected to surface production and/or storage equipment.
Fluid containment at the wellhead is accomplished with a polished rod and stuffing box. The polished rod is connected to the upper end of the rod string, and is reciprocated through the stuffing box by the pump drive. The stuffing box contains a series of compression rubbers for accommodating movement of the polished rod without incurring fluid loss at the top of the tubing string.
A problem which exists with lifting systems of the character described is the likelihood of a leak developing in the tubing string, and further, the potential for structural failure in the rod string used to actuate the pump. Due to the abusive down-hole environments in which artificial lifting systems are used, and more specifically due to the deleterious nature of the fluids to which lifting systems are subjected, the tubing strings and rod strings of the current art are susceptible to corrosion, scaling and abrasive wear from fluid borne solids.
In addition, due to the minimal clearances between the rod strings and the interior surface of the tubing strings, abrasions causing tubing wear and rod failure are commonplace. As can be understood from the above discussion, either of these incidents results in a loss of operability in the lifting system and requires time-consuming and expensive repair.
The present invention is directed toward overcoming the problems set forth above and advancing the state of the lifting system art by utilizing the weight savings and corrosion resistance properties uniquely associated with composite materials. In addition, the invention is directed to various features employed with such a composite system.
SUMMARY OF THE INVENTION
It is an object of the present invention, therefore, to provide a new and improved lifting system in which a composite tubing string is used for operating a reciprocating pump within the well and for transporting oil to the surface of the well.
In the exemplary embodiment of the invention, an artificial lifting system is designed for use at a pumping installation which has a pump drive at the surface or head end of a well and a reciprocating pump positioned in the lower end or foot of the well. The artificial lifting system has a tubing string connected between the pump drive and the pump for performing the dual functions of reciprocating the pump plunger in response to activation of the pump drive, and for transporting oil from the underground source to the wellhead.
The tubing string advantageously is constructed of a plurality of lightweight, non-metallic tubing segments which are axially connected to form an elongated conduit of several thousand feet in length. The individual segments are approximately 30 to 40 feet long and are made of a fiber reinforced composite material. In the preferred embodiment disclosed herein, the tubing segments are made of a thermosetting resin which is reinforced with glass and graphite fibers. Preferably, the fiber reinforced resin has a density of less than 0.1 pounds per square inch and a fiber content of approximately 60 percent by volume, with the resulting composite material having an elastic modulus in excess of 700,000 psi.
Non-metallic threaded fittings are attached at each end of the tubing segments to Join individual segments to form a conduit of desired length. The threaded fittings are formed of fiber reinforced resin and are entrapped and bonded within the tubing segments. Each segment of tubing includes one internally threaded fitting and one externally threaded fitting. Preferably, the thread forms on the fittings are produced without cutting the fiber reinforcement within the couplings and with a thread pitch less than six threads per inch. The externally threaded fitting at the end of each tubing segment is rotatably received in an associated internally threaded fitting in the end of an adjacent tube.
Oil which is transported upwardly through the composite tubing string is discharged at an upper end thereof through a perforated hollow tube. An elongated collection tube depends from the wellhead and has a peripheral sidewall which surrounds the perforated tube. A precision seal is provided at the lower end of the collection tube for slidably receiving the perforated tube. Because the lower end of the collection tube is sealed, the collection tube defines an annular collection chamber at the top of the tubing string for receiving oil which is discharged from the perforated tube.
An anchor mechanism fixes the top of the collection tube to the wellhead assembly. The wellhead defines an upward and outwardly tapered region surrounding the top of the collection tube. Toothed grips are wedged inside the tapered space engaged with the collection tube to prevent the collection tube from moving downwardly into the well. Rubber packing elements are placed above the toothed grips. A lower lockdown member is fixed to the wellhead and is clamped into engagement with the rubber packing elements by a wellhead cap assembly. The wellhead cap is threadedly engaged with the wellhead, which, in turn, is rigidly secured to the surface casing of the well. An annular upper lockdown member engages the upper end of the collection tube, and is drawn downwardly by a number of vertical adjustment rods connected between the upper lockdown member and the lower lockdown member. Movement of the upper lockdown member toward the lower lockdown member forces the collection tube downwardly and into continuous engagement with the toothed grips.
The lower lockdown member is split axially into two halves to facilitate installation of the wellhead assembly. Once the wellhead cap assembly is mounted over the lower lockdown member, a circular split plate is bolted to an unflanged upper end of the lower lockdown member. Split locations in the lower lockdown member and circular split plate are rotated to a staggered position 90 degrees apart to rigidly secure the assembly.
A metal/composite adaptor is located at each end of the composite tubing string and provides a transition between metallic components at the top and bottom of the well and the assembled composite tubing string. A metal/composite adaptor has a corrosion resistant metallic tube with a gentle taper at one end of the adaptor and a threaded attachment at the opposite end of the adaptor. A necked center section is provided between the opposite ends of the adaptor.
Composite material is wound over the taper of the metallic tube and is entrapped and bonded to the necked section of the tube. Circumferential fibers hold the composite in the necked region and provide a strong traplock feature when cured. Diametrically opposed pins on the adaptor extend radially outward through both the composite and metal near the threaded end of the adaptor to provide torsional resistance should the bond between the composite material and the metal fail. A composite fitting is entrapped and bonded in the tapered end of the metal/composite adaptor to facilitate attachment to the composite tubing string.
A locking mechanism near the bottom of the tubing string holds the pump assembly in constant position with respect to the well casing. The mechanism is of a type whereby an application of torque actuates a number of radially extendable toothed grips for securely engaging the well casing. A clearance is maintained between the locking device and the well casing to accommodate the free flow of gaseous material. The locking mechanism advantageously is locked and unlocked without removal from the hole to allow full control of its placement within the well bore.
A J-lock mechanism is attached to the bottom of the composite tubing string and permits the transmission of torque to the lower portion of the tubing string by rotating the upper end of the string assembly, and, in addition, permits the upper end of the string assembly selectively to be reciprocated independently of the lower tubing string portion. The mechanism includes a J-lock body connected to the upper tubing string portion and a J-lock sleeve connected to the lower tubing string. The J-lock body is received in the J-lock sleeve and is selectively disengaged therefrom to permit reciprocation of the upper tubing string portion.
A reciprocating pump includes a plunger, a pump barrel for guiding reciprocal movement of the plunger, and a plunger cage valve assembly. The plunger is suspended within the pump barrel by a plunger tube connected to the J-lock body. The plunger cage assembly is connected to the bottom of a protective tube which extends downwardly from the J-lock sleeve. The pump barrel is encased within the protective tube and is attached at its bottom to the plunger cage assembly.
A bottom lock adaptor threadedly engages a standard tubing coupling which attaches the protective tube surrounding the pump. The bottom lock adaptor provides a threaded attachment point for the bottom locking mechanism and the cage assembly, with the lower end of the pump barrel supported on the cage assembly. The locking device is connected to the bottom of the protective tube by means of a cylindrical tubing coupling and a bottom lock adaptor.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and advantages, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which:
FIG. 1 is a schematic illustration of an artificial lifting system in which the present invention is employed;
FIGS. 2-10 are diagrammatic illustrations of the present lifting system, in downward sequential order of sections of the lifting system from the top wellhead to the bottom pump;
FIG. 11 illustrates the construction of a composite tubing segment;
FIG. 12 illustrates an alternative embodiment of a composite connectors for joining a pair of adjacent composite tubing segments;
FIG. 13 illustrates the trap lock feature of the composite connectors;
FIG. 14 illustrates a metal/composite transition member;
FIGS. 15 and 16 illustrate alternative embodiment of an anti-abrasion element; and
FIG. 17 and 18 illustrate the a J-lock body and J-lock sleeve, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The artificial lifting system of the present invention is illustrated schematically in FIG. 1 and is generally designated 8. The artificial lifting system is shown in a hydrocarbon producing application wherein a well bore 10 extends from the surface of the earth 12 down to an oil bearing formation 14. A wellhead 16 is fixed to a well casing 18, and a reciprocating pump 20 is fixed within the lower end of well bore 10 by a locking device 21 and is connected to the wellhead by a hollow string assembly, generally designated 22. Pump drive means in the form of a generally known jack unit 24 is mounted at the surface and, as will be discussed below, is operable to reciprocate string assembly 22. Reciprocation of the string assembly is effective to perform the dual functions of activating pump 20 and transporting oil from formation 14 upwardly through the well to fluid collection means, generally designated 25. Fluid is accumulated by collection means 25 and is discharged through a fluid outlet 26.
FIGS. 2-10 illustrate in a downwardly sequential fashion the components which comprise artificial lifting system 8. In order to facilitate an understanding of the lifting system, the top and bottom portions of FIGS. 2-10 include what is believed an appropriate degree of overlap with respect to the preceding and subsequent illustrations. Details of the specific components are recited following the sequential description provided hereinbelow.
Beginning with FIGS. 2 and 3, a solid polished rod 28 is reciprocally driven by jack unit 24 through a stuffing box 30 on wellhead 16. A rod rotator 29 movably receives polished rod 28 and is operatively engaged with jack unit 24 for incrementally rotating polished rod 28 a predetermined number of degrees during each stroke of the jack unit. The polished rod is connected in series to a polished hollow tube 32 by means of a threaded coupling 33 which is received in the upper end of well casing 18. The polished hollow tube has a number of perforations 32a which communicate with the interior of hollow tube 32.
Referring next to FIGS. 4-6, hollow string assembly 22 includes composite tube means 34 coupled for vertical reciprocation with perforated tube 32. The composite tube means extends downwardly through the well bore to engage reciprocating pump 20 and is connected to the perforated tube 32 by a threaded polished tube adaptor 35 and an elongated metal/composite adaptor 37. Adaptor 37 advantageously is constructed of corrosion resistant metal and has a threaded upper end 37a engaged with polished tube adaptor 35 and a tapered lower end 37b bonded and entrapped within a composite tube connector 37c.
Composite tube means 34 is made up of a plurality of serially connected tubing segments, with each tubing segment having a length of approximately 40 feet. The construction of the individual tubing segments, as well as the manner in which the segments are connected, provide the strength of prior art lifting systems while greatly reducing corrosion and other degradation arising from hazards normally associated with doom-hole hydrocarbon-producing environments.
More specifically, and as described in greater detail below, composite tube means 34 is formed from a carbon and glass fiber-reinforced thermosetting epoxy resin in which the fibrous reinforcements make up approximately 60% of the composite material by volume. The composite material preferably has a density less than 0.1 pounds per cubic inch and provides an axial modulus of elasticity in excess of 700,000 psi. As a result of the strong, relatively lightweight construction of the individual tubing segments, the artificial lifting system is capable of reciprocating a composite tube which has a length sufficient to extract oil from well formations at depths ranging from approximately 2,000 feet to 12,000 feet below the surface of the earth.
Connector means, designated generally 50 in FIG. 5, are provided for joining the ends of a pair of adjacent composite tube segments 52 and 54. Of course, as noted above, the present invention envisions a tubing string 22 having a sufficient number of tube segments to collectively form a tube having a length sufficient to extract oil from a desired depth. Connector means 50 include tubular fittings 56 and 58 which cooperate to securely mate the adjacent tube segments and provide an impermeable seam for preventing the leakage of fluid which is transported by composite tube means 34. An anti-abrasion element 78 is mounted exteriorly of the seam between the ends of tube segments 52 and 54, respectively. Anti-abrasion element 78 prevents composite tube means 34 from striking well casing 18 during pumping operations. Rotation of polished rod 28 and string assembly 22 by rod rotator 29 assures uniform wear around the periphery of anti-abrasion elements 78.
An elongated metal/composite adaptor 80 is connected at the bottom of composite tube means 34. Metal/composite adaptor 80 is similar to adaptor 37 and is constructed of corrosion resistant metal. Adaptor 80 has a tapered upper end 80a bonded to a composite tube connector 80b and a threaded lower end 80c threadedly engaged with a cylindrical tubing drain 82.
As shown also in FIG. 7, a two-piece J-lock mechanism 84 is connected below tubing drain 82 and permits the upper end of string assembly 22 to be selectively disengaged from pump 20 and locking device 21. To this end, J-lock mechanism 84 has a reciprocable body 85 releasably engaged with an elongated sleeve 86. A centralizing member 90 positions J-lock sleeve 86 within casing 18. For reasons which wall become apparent from the description below, the J-lock mechanism permits the transmission of torque to the lower portion of the tubing string by rotating the upper end of the string assembly, and, in addition, permits the upper end of the string assembly to be reciprocated independently of the lower portion of lifting system 8.
Pump 20 has a reciprocable plunger 94 (FIG. 8) and a cylindrical pump barrel 96. Plunger 94 is connected to J-lock body 85 with a rigid plunger tube 97 and a plunger tube adapter 98. The plunger tube adapter is cylindrical metal coupling having internally threaded opposite ends for interconnecting plunger tube 97 and reciprocable plunger 94. Pump barrel 96 is housed within a tubing segment 100 which, in turn, extends from a tubular adaptor 102 connected to J-lock centralizer 92. The pump barrel is positioned within tubing segment 100 by a pump barrel centralizer 104 and extends downwardly through casing 18 to a plunger cage and valve assembly 106. The cage and valve assembly is internally attached to the bottom of tubing segment 100 and supports pump barrel 96 within the tubing segment. Bottom locking device 21 is connected to the bottom of tubing segment 100 by means of a cylindrical tubing coupling 108 and a bottom lock adaptor 110.
Referring lastly to FIGS. 9 and 10, bottom locking device 21 is a hollow elongated mechanism having two axially spaced series of radially extendable toothed locking slips 112. More particularly, it is envisioned that locking device 21 is of a commercially available character wherein locking slips 112 are alternatively extended and retracted in response to the application of torque or axial force to the upper end of string assembly 22. The extended locking slips engage the interior sidewall of well casing 118 to anchor the bottom of lifting system 8 during pumping operations. A perforated nipple 114 extends downwardly from a coupling 116 on locking device 21 and terminates at a bull plug 118.
Operation of lifting system 8 is summarized briefly as follows. Once an appropriate vertical well bore is drilled through the earth, well casing 18 is lowered into the well and wellhead 16 is secured to the upper end of the casing. The aforesaid components then are sequentially assembled and lowered through the well casing, beginning with bull plug 118 and perforated nipple 114. Bottom locking device 21 and pump 20 are then attached and lowered through the casing, followed by the described components of string assembly 22.
Following the installation of all of the aforesaid components, a torque is applied to the top of tubing string 22 to actuate locking slips 112 and anchor the bottom of lifting system 8 within the well. Application of torque disengages J-lock body 85 from J-lock sleeve 86 to permit vertical reciprocation of composite tube means 34, plunger tube 97, and plunger 94 independently of pump barrel 96. Relative axial movement between the pump plunger and pump barrel 96 draws oil from formation 14 through perforated nipple 114 and upwardly through composite tube means 34 and into collection means 25.
As discussed above with respect to composite tube means 34, the tubing string is made up of a plurality of serially connected fiber-reinforced tube segments, with a representative tube segment designated generally 120 in FIG. 11. As previously discussed, the composite fiber and resin construction of the tube segments results in tube segments which have a density less than 0.1 pounds per cubic inch, and provide an axial modulus of elasticity in excess of 700,000 psi.
A preferred arrangement of reinforcing fibers which provides an axial modulus of elasticity in excess of 5,000,000 psi is illustrated in FIG. 11 with respect to tube segment 120, wherein it can be seen that the tube segment has a plurality of coaxial cylindrical layers or plies 122, 124, and 126. Each of the coaxial plies contains a thickness of wound fibers which are oriented with respect to the longitudinal axis of tube segment 120 so as provide the aforesaid material stiffness in segment 120.
In one construction, ply 122 has "hoop" fibers 128 which are wound about tube segment 20 at an angle of substantially ninety degrees with respect to the longitudinal axis of the tube segment and carry hoop or pressure loads. Accordingly, fibers 128 in ply 122 must be of a type possessing sufficient integrity to withstand internal pressurization of tube segment 120. Glass fibers which are wound to a thickness of approximately 0.120 inches have been found to provide acceptable levels of performance in ply 122 in wells having a depth of approximately 5,000 feet.
Ply 124 has "longitudinal" fibers 130 which are wound in alternating directions and at small angles with respect to the longitudinal axis of tube segment 120, such as plus and minus ten degrees. Due to the orientation of fibers 130, the fibers are adapted to carry axial loads and must be of a type possessing sufficient cyclic fatigue resistance to support the weight of lifting system 8. Carbon fibers which are wound to a thickness of approximately 0.050 inches have been found to provide acceptable levels of performance in ply 124 in wells having a depth of approximately 5,000 feet.
More particularly, carbon fibers characteristically provide relatively high resistance to static and dynamic fatigue failure. In terms of percent ultimate stress, the capability of carbon/epoxy composite materials to sustain static loads decreases over time at a more gradual rate than the decrease in static strength of other filament wound materials, such as fiberglass. Carbon/epoxy composite material also provides a substantially more constant relationship between the percentage of static strength which can be dynamically withstood as a function of fatigue cycles. Consequently, cyclic loading does not have as great an effect on the strength of the lifting system as in systems employing other filament wound materials, such as fiberglass.
Ply 126 has "helical" fibers 132 which are wound about tube segment 120 at alternating directions with respect to the longitudinal axis of the tube segment, such as plus and minus forty-five degrees. Due to the orientation of fibers 132, the fibers are adapted to carry torsional loads and must be of a type possessing sufficient integrity to transmit torque between the upper end and the lower end of tubing string 22. Glass fibers which are wound to a thickness of approximately 0.060 inches have been found to provide acceptable levels of performance in ply 126 in wells having a depth of approximately 5,000 feet.
The following discussion relates to the construction of connector means 50, as shown in FIGS. 5, 12 and 13. First referring to FIG. 5, tube segment 52 has a flared end 62 with a tapered inner sidewall 64. Tube segment 54 has a flared end 66 with a tapered inner sidewall 68. Fittings 56 and 58 are generally molded cylindrical tubes which are bonded to the respective composite tube segments by an adhesive film layer applied at the interface between the components. Fitting 56 has an internally threaded opening 56a for receiving an externally threaded end 58a of fitting 58. In an alternative connector illustrated in FIG. 12, an internally threaded molded fitting 56' is bonded to each opposite end of a pair of adjacent tube segments. A cylindrical fitting 58' having axially spaced externally threaded ends is provided for joining the segments.
Tube segments 52 and 54 have a smooth inner sidewall 79 and 80, respectively, to facilitate the transportation of oil from reciprocating pump 20 to outlet 26. Each fitting 56 and 58 has a smooth inner sidewall portion 56b and 58b, respectively, which is aligned with the sidewalls 79 and 80 when the tube segments 52 and 54 are connected. The fittings are formed of fiber reinforced resin. Preferably the thread forms on the fittings are produced without cutting the fiber reinforcement and have a thread pitch less than six threads per inch.
FIG. 13 illustrates an exemplary construction of a film-adhesive bond for joining a threaded fitting with an associated composite tube segment. As shown in FIG. 13, a threaded fitting 134 has a tapered peripheral sidewall 136 which is bonded With a generally cylindrical sidewall 138 on a composite tube segment 140. An adhesive bond, generally designated 142, is established between tapered surface 136 and cylindrical surface 138 such that fitting 134 cannot be axially extracted from composite tube segment 140 without destroying the bond in a shear direction. More specifically, adhesive bond 142 is made up of adjacent layers of carbon' fiber 144 and surrounding carbon hoop plies 146. A thin layer of adhesive is applied between the adjacent layers 144 and 146 and sidewalls 136 and 138 to form a high strength trap for rigidly bonding the insert and the composite tube segment. In order for the fitting to move to the left, as shown in FIG. 13, the high strength carbon hoop ring 146 must separate or break before the fitting can be withdrawn.
The described "traplock" also is provided on the metal/composite transition members 37 and 80. As shown with respect to transition member 37 in FIG. 14, each transition member includes a center section 37d necked to a smaller diameter intermediate a threaded opening at one end 37a and a gentle taper at an opposite end 37b. Composite material is wound over the taper of the transition member and is entrapped and bonded to the member in necked section 37d. Circumferential fibers hold the composite in the necked region and provide the noted traplock feature when cured. Pins 37e extend diametrically through the composite and the threaded end of member 37 to provide torsional resistance should the bond between the composite material and the member 37 fail. A rubber liner 37f is bonded between the member 37 and the composite material.
Anti-abrasion elements 78 are illustrated in FIGS. 15 and 16 and prevent composite tube means 34 from striking well casing 18 during pumping operations. In the preferred embodiment shown in FIG. 15, an anti-abrasion element 78 has a carrier 148 with a central opening 150 for receiving hollow string assembly 22. A plurality of rotatable elements 152 have associated axles 154 journaled on carrier 148. Rotatable elements 152 extend radially outward of the periphery of carrier 148 and engage the interior wall of well casing 18 to reduce frictional resistance between the well casing and an anti-abrasion element 78 when string assembly 22 is reciprocated in the well.
Alternatively, and as shown in FIG. 16, an anti-abrasion element 78' is an annular collar formed of nylon or ultrahigh molecular weight (UHMW) polyethylene. Anti-abrasion element 78' has axially spaced end openings 78a' and 78b' for receiving the ends of a pair of adjacent composite tubing segments.
J-lock body 85 and J-lock sleeve 86 are shown in greater detail in FIGS. 17 and 18, respectively. J-lock body 85 has a hub 156 with a reduced diameter shaft 158 extending therefrom. Hub 156 has a circular bore 160 for receiving fluid drain 82, and the shaft 158 has a longitudinal passage 162 in communication with bore 160. A pair of diametrically opposed pins 164 extend laterally from J-lock body 85. The lower end 166 of J-lock body 85 has an exterior annular groove 168 and an interior annular groove 170. Referring also back to FIG. 7, annular groove 168 seats a coil spring 171 which is interposed between the J-lock body and J-lock centralizer 92. Plunger tube 97 is threadedly engaged with interior annular groove 170.
J-lock sleeve 86 is a cylindrical member having an axial passage 172 for receiving shaft 158 on J-lock body 85. A pair of generally J-shaped slots 174 are formed in the sidewalls of J-lock sleeve 86 and are adapted to receive diametrically opposed pins 164 on the J-lock body. More particularly, each slot 174 has a crook portion 176 in which an associated one of pins 164 is disposed when lifting system 8 is lowered into a well. That is, the weight of locking device 21 and the biasing force generated by coil spring 171 maintain pins 164 in corresponding crook portions 176 and hold J-lock mechanism 84 in a locked position.
When a clockwise (as looking downward through passage 172) torque is applied to the top of string assembly 22 pins 164 engage the sidewall 176a of the crook portions 176 and J-lock sleeve 86 similarly is caused to rotate in a clockwise direction. Thus, the torque is transmitted to locking device 21, and the toothed locking slips 112 are extended into engagement with well casing 18. A counterclockwise torque then is applied to the top of string assembly 22 to rotate pins 164 out of engagement with sidewalls 176a. The J-lock body is rotated until pins 164 engage an axial slot portion 177 on each slot 174. String assembly 22 then is lifted to disengage J-lock body 85 from J-lock sleeve 86, whereby tubing string assembly 22 and plunger 94 can be reciprocated independently of pump barrel 96.
To remove the lifting system from a well, J-lock body 85 is lowered into engagement with J-lock sleeve 86 and pins 164 are guided downwardly through axial slot portions 177 of J-slots 174. When the J-lock body is fully lowered, string assembly 22 is rotated in a clockwise direction to move pins 164 into engagement with sidewalls 176a of crook portions 176. The torque is thereby transmitted to locking device 21, which, in turn, causes locking slips 112 to retract. The thusly unsupported weight of locking device 21 pulls J-lock sleeve 86 downward and forces pins 64 relatively upward into the crook portion 176 of each slot 174. String assembly 22 then can be extracted from the well bore.
Collection means 25 now will be discussed- As shown in FIG. 4, wellhead 16 is secured to the top of well casing 18 during installation of the well and is stationary with respect to ground. A wellhead cap 180 surrounds the upper end of wellhead 16 and is attached thereto along a threaded interface 182. Wellhead cap 180 has a radial flange 184 for purposes to be described.
An elongated metal tube 186 extends downwardly through wellhead cap 180 and surrounds perforated tube 32 to form an annular collection chamber 188 around the perforated tube and polished rod 28. Fluid which is drawn from formation 14 upwardly through hollow string assembly 22 is discharged through perforations 32a into collection chamber 188. Precision seal means, generally designated 190, slidably receive the bottom of perforated tube 32 and prevent fluid received in collection chamber 188 from leaking to the bottom of the well.
More particularly, and as shown in greater detail in FIG. 4, precision seal means 190 include a plurality of upward and outwardly flared cup seals 192 stacked within a cylindrical seal housing 194. The seal housing is connected to the bottom end of elongated tube 186 by an adaptor 196. A lower end 197 of seal housing 194 is engaged with a cylindrical seal retainer 198 and a coaxial seal compressor 199. A coil spring 200 is interposed between spring compressor 199 and the bottommost cup seal 192. Axially spaced spring centralizers 201a and 201b have an annular groove for seating opposite ends of spring 200. The coil spring continuously compresses cup seals 192 upward against adaptor 196. The cup-shaped construction of the seals causes an application of compressive axial force to continuously urge the seals into engagement with perforated tube 32 regardless of wear of cup seals 192.
Lockdown means, generally designated 202, are provided at the head of the well for supporting metal tube 186 at wellhead 16. As best illustrated in FIGS. 2 and 3, lockdown means 202 has a split lower lockdown member 204 with an annular flange 206 which is captured beneath flange 184 on wellhead cap 180. A rubber packing element 208 and tapered locking slips 210 are held against an upward and outwardly tapered wall 211 on wellhead 16. Locking slips 210 have a toothed wall 212 for engaging metal tube 186.
In order to provide a downward force on metal tube 186, lockdown means 202 has an upper lockdown member 212 with an integral collar 214 and a split plate 216 associated with lower lockdown member 204. Split plate 216 is attached to an unflanged upper end 218 of lower lockdown member 204 with a plurality of screws 220 after wellhead cap 180 is installed. Split locations in lower lockdown member 204 and split plate 216 are rotated to a position ninety degrees apart to provide a rigid unit when the two components are fastened together.
Upper lockdown member 212 is threadedly engaged at an upper end thereof with a standard T-fitting 220. The lower end of upper lockdown member 212 has an interior annular groove 222 for receiving the upper end of elongated metal tube 186. In order to apply and maintain a downward force on tube 186, a plurality of circumferentially spaced vertical rods 224 are secured between lockdown members 212 and 204 by means of internally threaded nuts 226. Appropriate rotation of nuts 226 draws lockdown members 212 and 204 toward each other and forces elongated tube 186 downward and into engagement with locking slips 210. The locking slip, in turn, are wedged into the annular space defined by upward and outwardly tapered wall 211 on wellhead 16.
It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.
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An artificial lifting system is designed for use at a pumping installation which has a pump drive at the surface or head end of a well and a reciprocating pump positioned in the lower end of the well. The artificial lifting system has a tubing string connected between the pump drive and the pump for performing the dual functions of reciprocating the pump plunger in response to activation of the pump drive, and for transporting oil from the underground source to the wellhead. The tubing string advantageously is constructed of a plurality of lightweight, non-metallic tubing segments which are axially connected to form an elongated conduit of several thousand feet in length. In the exemplary embodiment, the tubing segments are made of a glass and carbon reinforced epoxy resin. Preferably, the composite material has a density of approximately 0.1 pounds per cubic inch and a fiber content of approximately 60% by volume, with the resulting composite material having an elastic modulus in excess of 700,000 psi. The invention additionally is directed to various structural features for facilitating the implementation of such a composite lifting system.
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RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2011-021278 filed on Feb. 3, 2011, the entire content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a slide processing apparatus for processing a slide within a cassette.
2. Description of the Related Art
There are known conventional specimen staining apparatuses for holding a smeared specimen on a slide enclosed in a specimen cassette and automatically performing a staining process on the held specimen (for example, Japanese Laid-Open Patent Publication No. 2006-38781). The specimen staining apparatus disclosed in Japanese Laid-Open Patent Publication No. 2006-38781 stains a specimen by injecting a staining liquid into a specimen cassette which holds the specimen, and after the staining process washes the specimen by injecting water into the specimen cassette.
In the specimen staining apparatus disclosed in Japanese Laid-Open Patent Publication No. 2006-38781, staining liquid may adhere inside the specimen cassette following repeated use of the specimen cassette. Therefore, in order to repeatedly use the specimen cassette, the user must manually wash the specimen cassette to remove the staining liquid adhered inside the specimen cassette.
SUMMARY OF THE INVENTION
A first aspect of the present invention is a slide processing apparatus comprising: a liquid transporter for transporting a staining liquid reserved in a first liquid container and a washing liquid reserved in a second liquid container; a first instruction receiver for receiving a first instruction that instructs to initiate preparation of a slide stained with the staining liquid; a second instruction receiver for receiving a second instruction that instructs to initiate washing of a housing element which accommodates therein a slide to be stained; and a controller, wherein, when receiving the first instruction, the controller performs staining of the slide accommodated in the housing element by causing the liquid transporter to transport the staining liquid into the housing element; and, when receiving the second instruction, the controller performs washing of the housing element by causing the liquid transport to transport the washing liquid into the housing element.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing the structure of an embodiment of a clinical sample processing apparatus;
FIG. 2 is a plan view showing the structure of an embodiment of a smear preparation apparatus viewed from above;
FIGS. 3( a ) and 3 ( b ) are perspective views showing the structure of an embodiment of a cassette;
FIGS. 4( a )- 4 ( c ) show the operation of the staining unit of the embodiment;
FIG. 5 briefly shows a fluid circuit diagram of the smear preparation apparatus of the embodiment;
FIG. 6 shows the structure of a first methanol chamber of the embodiment;
FIG. 7 briefly shows the structures of a transport device and the smear preparation apparatus of the embodiment;
FIG. 8 is a flow chart showing the processes of the smear preparation apparatus of the embodiment;
FIGS. 9( a ) and 9 ( b ) show a start setting screen and a shutdown setting screen of the embodiment;
FIGS. 10( a ) and 10 ( b ) are flow charts showing the methanol dispensing process in the staining process and smear preparation process of the embodiment;
FIGS. 11( a ) and 11 ( b ) show threshold number setting screen and a flow chart of the threshold number setting process of the embodiment;
FIGS. 12( a ) and 12 ( b ) are flow charts of the cassette washing process and a flow chart of the methanol dispensing process in the washing process of the embodiment;
FIGS. 13( a ) and 13 ( b ) are flow charts of the methanol collection process and the counting process of the collection counter of the embodiment;
FIG. 14 is a flow chart of the methanol replacement process of the first methanol chamber of the embodiment;
FIG. 15 is a flow chart of the methanol supplying process of the first methanol chamber and the second methanol chamber of the embodiment; and
FIGS. 16( a )- 16 ( f ) show specific examples of the washing process of the embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present embodiment is an application of the invention in a clinical sample processing apparatus for preparing a smear sample from a blood sample. The clinical sample processing apparatus of the present embodiment is provided with a smear preparation apparatus and a transport device. Note that the necessity of preparing a smear sample is usually determined based on blood sample analysis results of a blood analyzer or the like at a previous stage. When preparing a smear sample, a sample rack holding a sample container which contains a sample is placed in the transport device. Subsequently, the sample rack is moved by the transport device and a smear sample is prepared by the smear preparation apparatus.
The embodiment of the clinical sample processing apparatus is described below with reference to the drawings.
FIG. 1 is a perspective view showing the structure of a clinical sample processing apparatus 1 . The clinical sample processing apparatus 1 is provided with a smear sample preparation device 2 and a transport device 3 . Note that below the X-axis positive direction is referred to as the left direction, the X-axis negative direction is the right direction, the Y-axis positive direction is the backward direction, the Y-axis negative direction is the forward direction, the Z-axis positive direction is the upward direction, and the Z-axis negative direction is the downward direction.
The smear sample preparation device 2 is provided with an operation display unit 2 a configured by a touch panel disposed on the front surface of a cover. openings 2 b and 2 c are respectively formed at the top right and top left of the front surface of the cover of the smear sample preparation device 2 . The smear sample preparation device 2 also has a hand unit 41 a for holding a sample container T through an opening 2 d . The user controls the smear sample preparation device 2 by operating the operation display unit 2 a , sets a cassette 20 in a cassette receiver 47 (refer to FIG. 2 ; described later) through the opening 2 c , and removes the cassette 20 deposited in the cassette storage unit 51 (refer to FIG. 2 ; described later) through the opening 2 c.
Bottle 101 through 105 for containing staining liquid and the like to be used by a staining unit 50 (described later) are connected to the smear sample preparation device 2 . In the present embodiment, the bottles 101 through 105 respectively contain methanol, May-Grünwald solution (staining liquid), Giemsa solution (staining liquid), phosphate buffer solution (diluting liquid), and water for washing samples. Two chambers (a first methanol chamber 111 and a second methanol chamber 112 ) containing methanol are also connected to the smear sample preparation device 2 .
Note that, in addition to the first methanol chamber 111 and second methanol chamber 112 , the smear sample preparation device 2 is also connected to a first staining liquid chamber 121 , second staining liquid chamber 122 , staining liquid chamber 131 , diluting liquid chamber 143 , first mixing chamber 151 , second mixing chamber 152 , and discard chamber 165 , as shown in FIG. 5 .
The transport device 3 is arranged at the front side of the smear sample preparation device 2 , and has a loader 3 a and an ejector 3 b . The transport device 3 transports a sample rack L that is positioned on the loader 3 a to the ejector 3 b . When the sample rack L is positioned in front of the hand unit 41 a , the sample rack L is removed therefrom by the hand unit 41 a and placed within the smear sample preparation device 2 .
FIG. 2 is a plan view showing the structure of the smear sample preparation device 2 viewed from above.
The smear sample preparation device 2 is provided with an aspirating/dispensing mechanism 41 , slide glass supplier 42 , slide glass cross-feeder 43 , smearing mechanism 44 , smear drier 45 , printer 46 , cassette receiver 47 , cassette cross-feeder 48 , cassette rotator 49 , staining unit 50 , and cassette storage unit 51 .
The aspirating/dispensing mechanism 41 has a hand unit 41 a , piercer (aspirating needle) 41 b , and dispensing pipette 41 c . A sample container T that is positioned in front of the hand unit 41 a is removed from the sample rack L that is gripped by the hand unit 41 a . Then, the blood sample accommodated in the sample container T is aspirated by the piercer 41 b , and dripped by the laterally movable dispensing pipette 41 c onto a slide glass 10 that is position in front of the smearing mechanism 44 .
The slide glass supplier 42 holds a plurality of new slide glasses 10 , and sequentially moves new slide glasses 10 up to the slide glass cross-feeder 43 . The slide glass cross-feeder 43 moves the new slide glass 10 supplied from the slide glass supplier 42 in a leftward direction to position the slide glass 10 in front of the smearing mechanism 44 .
The smearing mechanism 44 smears the blood sample when the blood sample is dripped onto the slide glass 10 positioned in front of the smearing mechanism 44 . The slide glasses 10 bearing the smeared blood samples are moved in the rightward direction by the slide glass cross-feeder 43 and positioned directly below the printer 46 and in front of the smear drier 45 . The smear drier 45 dries the blood sample smeared on the slide glass 10 positioned in front of the smear drier 45 via a fan (not shown in the drawing). The printer 46 is a printer (not shown in the drawing) that prints the sample number, day, receipt number, name and the like on the end of the slide glass 10 .
The cassette receiver 47 has a belt 47 a that is movable in a forward direction, and transmission type sensors 47 s configured by a light emitter and a light receiver disposed near the front end and the back end of the belt 47 a . The user can place an empty cassette 20 on the belt 47 a through the opening 2 b (refer to FIG. 1 ). The empty cassette 20 placed on the belt 47 a is transported by the moving belt 47 a in a forward direction. The sensors 47 s detect whether a cassette 20 is placed on the belt 47 a.
FIGS. 3( a ) and ( b ) are perspective views showing the structure of the cassette 20 . Note that FIGS. 3( a ) and ( b ) show the coordinate axes of FIG. 2 when the cassette 20 is placed on the belt 47 a.
Referring to FIG. 3( a ), the cassette 20 is formed of resin, and has a thickness in the Y-axis direction so as to accommodate a slide glass 10 in a receiver 20 e . Receiving holes 20 a and 20 b , which are laterally partitioned by a partition 20 c , are formed on the top part of the cassette 20 . The receiver 20 e is formed within the cassette 20 with a partition 20 d arranged in the downward direction of the partition 20 c . Flanges 20 f and 20 g are formed on the lateral sides of the cassette 20 , and the bottom surface of the flanges 20 f and 20 g are disposed on the belt 47 a of FIG. 2 and maintained thus by the bottom surface of the flanges 20 f and 20 g . A bottom part 20 h is formed below the cassette 20 . The slide glass 20 can be inserted from the top side through the receiving hole 20 a.
FIG. 3( b ) is a perspective view showing the slide glass 10 accommodated in the cassette 20 , as shown in FIG. 3( b ), when the slide glass 10 is accommodated, there is a gap in the region on the right side of the partitions 20 c and 20 d in the receiver 20 e . This gap allows the insertion of a pipette through the receiving hole 20 b even when a slide glass 10 is accommodated in the cassette 20 .
Returning to FIG. 2 , the cassette cross-feeder 48 has a cassette support 48 a , a laterally movable belt 48 b , and transmission type sensors 48 s configured by a light emitter and a light receiver. The cassette support 48 a is attached to the belt 48 b so as to support the bottom part 20 h of the cassette 20 in an upward direction. An empty cassette 20 which is positioned in front of the cassette receiver 47 is supported by the cassette support 48 a and transported leftward to in front of the cassette rotator 49 . The sensors 48 s are positioned in front of the cassette rotator 49 to detect whether a slide glass 10 is accommodated in the cassette 20 that is positioned in front of the cassette rotator 49 supported on the cassette support 48 a.
The cassette rotator 49 has a flat surface 49 a . The flat surface 49 a is configured so as to rotate while maintaining parallel to the X-Y plane and parallel to the X-Z plane. The cassette rotator 49 receives the empty cassette 20 positioned in front of the cassette rotator 49 , and the slide glass 10 is pushed from the printer 46 into the cassette 20 . Then, the cassette 20 , which contains the slide glass 10 on the flat surface 49 a , is moved to the cassette support 48 a of the cassette cross-feeder 48 . Subsequently, the cassette 20 is transported leftward by the cassette cross-feeder 48 and positioned in front of the staining unit 50 .
The staining unit 50 has a feed unit 50 a , belt 50 b that is movable in a backward direction, methanol processing unit M, stain processing units D 1 through D 3 , wash processing unit W, and feed unit 50 c . Each processing unit includes dispensing pipettes Ma, D 1 a , D 2 a , D 3 a , and Wa, collecting pipettes D 1 b , D 2 b <D 3 b , and Wb, and sensors Ms, D 1 s , D 2 s , D 3 s , and Ws.
The sensor Ms is a transmission type sensor configured by a light emitter and light receiver to detect when a cassette 20 is positioned at a position Mp (left end position of the cassette cross-feeder 48 ) for processing by the methanol processing unit M. The sensors D 1 s , D 2 s , D 3 s , and Ws are contact type sensors for detecting a cassette 20 respectively positioned at the stain processing units D 1 , D 2 , D 3 , and positions D 1 p , D 2 p , D 3 p , and Wp for processing by the wash processing unit W.
When the cassette 20 is detected by the sensor Ms, methanol is dispensed from the receiving hole 20 b of the cassette 20 into the receiver 20 e via the dispensing pipette Ma of the methanol processing unit M. At this time, the cassette 20 is supported by the cassette support 48 a of the cassette cross-feeder 48 . Thereafter, the cassette 20 is fed onto the belt 50 b by the feeding unit 50 a.
The cassette 20 which has been fed onto the belt 50 b by the feeding unit 50 a is supported by the flanges 20 f and 20 g . In this state, the cassette 20 is transported backward by the moving belt 50 b.
When the cassette 20 is detected by the sensor D 1 s , the methanol inside the receiver 20 e is recovered (aspirated) from the receiving hole 20 b of the cassette 20 via the recovery pipette D 1 b of the stain processing unit D 1 . The smear sample on the slide glass 10 is then dried by a fan not shown in the drawing. The fixing (adhesion) of the smear sample by methanol then ends. Subsequently, May-Grünewald solution is dispensed (discharged) into the receiver 20 e of the receiving hole 20 b of the cassette 20 via the dispensing pipette D 1 a . The cassette 20 is then transported backward by the belt 50 b.
When the cassette 20 is detected by the sensor D 2 s , the May-Grünewald solution inside the receiver 20 e is recovered (aspirated) from the receiving hole 20 b of the cassette 20 via the recovery pipette D 2 b of the stain processing unit D 2 . Subsequently, May-Grünewald diluting liquid is dispensed (discharged) into the receiver 20 e of the receiving hole 20 b of the cassette 20 via the dispensing pipette D 2 a . The cassette 20 is thereafter transported backward by the belt 50 b . Note that the May-Grünewald diluting liquid is a mixture of the May-Grünewald solution of bottle 102 and diluting liquid of bottle 104 .
When the cassette 20 is detected by the sensor D 3 s , the May-Grünewald solution inside the receiver 20 e is recovered (aspirated) from the receiving hole 20 b of the cassette 20 via the recovery pipette D 3 b of the stain processing unit D 3 . Then, Giemsa diluting liquid is dispensed (discharged) into the receiver 20 e of the receiving hole 20 b of the cassette 20 via the dispensing pipette D 3 a . The cassette 20 is thereafter transported backward by the belt 50 b . Note that the Giemsa diluting liquid is a mixture of the Giemsa solution of bottle 103 and diluting liquid of bottle 104 .
When the cassette 20 is detected by the sensor Ws, the Giemsa liquid inside the receiver 20 e is recovered (aspirated) from the receiving hole 20 b of the cassette 20 via the recovery pipette Wb of the wash processing unit W. Then, water used for sample washing is dispensed (discharged) into the receiver 20 e of the receiving hole 20 b of the cassette 20 via the dispensing pipette Wa. The water used for sample washing is then recovered (aspirated) from inside the receiver 20 e of the cassette 20 by the recovery pipette Wb. The cassette 20 is thereafter transported backward by the belt 50 b.
The cassette 20 which has been moved backward by the belt 50 b is then sent leftward by the feed unit 50 c . The cassette 20 is therefore positioned at the back of the cassette storage unit 51 .
The cassette storage unit 51 has a feeding unit 51 a and a belt 51 b which is movable in a forward direction. The cassette 20 which has been sent from the feed unit 50 c is moved onto the belt 51 b by the feeding unit 51 a . The cassette 20 which has been sent onto the belt 51 b is transported forward by the moving belt 51 b . The cassette 20 positioned in front of the belt 51 b is removed by the user through the opening 2 c (refer to FIG. 1 ). The smear sample preparation therefore ends. Note that the cassette 20 which has been recovered in the cassette storage unit 51 and removed by the user through the opening 2 c (refer to FIG. 1 ), is thereafter again placed in the cassette receiver 47 through the opening 2 b (refer to FIG. 1 .
The operation of the staining unit 50 (methanol processing unit M, stain processing units D 1 through D 3 , and wash processing unit W) is described next, referring to FIG. 4 . Note that the operation of the methanol processing unit M, stain processing units D 1 through D 3 , and wash processing unit W is identical to that of the stain processing unit D 1 .
FIGS. 4( a ) through ( c ) are side views of the stain processing unit D 1 viewed in the Y-axis positive direction. The stain processing unit D 1 has, in addition to the dispensing pipette D 1 a and recovery pipette D 1 b shown in FIG. 2 , a substrate D 11 , stopper D 12 , support member D 13 , and holder D 14 .
Referring to FIG. 4( a ), the substrate D 11 is attached within the smear sample preparation device 2 . The stopper D 12 is a metal plate which is vertically movable (Z-axis direction) relative to the substrate D 11 , and the sensor D 1 s is provided on the front surface (surface on the side in the Y-axis negative direction) of the stopper D 12 . The dispensing pipette D 1 a , recovery pipette D 1 b , and holder D 14 are integrated with the support member D 13 so as to be vertically movable.
In the state shown in FIG. 4( a ), the backside surface of the cassette 20 , which has been transported backward supported on the belt 50 b , abuts the stopper D 12 and is stopped. At this time, the cassette 20 is positioned at position D 1 p of FIG. 2 , and the arrival of the cassette 20 is detected by the sensor D 1 s . In this state, the support member D 13 moves downward and the tips of the dispensing pipette D 1 a and recovery pipette D 1 b are positioned within the receiver 20 e of the cassette 20 as shown in FIG. 4( b ).
In the state shown in FIG. 4( b ), the methanol within the cassette 20 is recovered by the recovery pipette D 1 b . The slide glass 10 in the cassette 20 is then gripped by the holder D 14 and lifted upward from the cassette 20 . In this condition, the slide glass 10 is dried by a fan not shown in the drawing, and thereafter the slide glass 10 is returned into the cassette 20 . May-Grünwald solution is then dispensed into the cassette 20 from the dispensing pipette D 1 a . The support member D 13 and the stopper D 12 then move upward and in the state shown in FIG. 4( c ) the cassette 20 is transported backward by the belt 50 b.
Note that the methanol processing unit M has a configuration wherein the stopper D 12 of FIG. 4 corresponds to the recovery pipette D 1 b . In the methanol processing unit M, the slide glass 10 , which is accommodated in the cassette 20 positioned at position Mp (refer to FIG. 2 ), is raised upward by the holder corresponding to the holder D 14 of FIG. 4 , and thereafter methanol is dispensed to the cassette 20 via the dispensing pipette Ma. The raised slide glass 10 is then returned into the cassette 20 . Thereafter, the cassette 20 is fed onto the belt 50 b by the feeding unit 50 a.
The stain processing unit D 2 , stain processing unit D 3 , and wash processing unit W have a structure corresponding to the holder D 14 of FIG. 4 . In the stain processing unit D 2 , stain processing unit D 3 , and wash processing unit W, staining liquid and the like is dispensed and recovered while the slide glass 10 is housed in the cassette 20 respectively positioned at position D 2 p , D 3 p , and Wp.
The cassette 20 stored in the cassette storage unit 51 is again placed in the cassette receiver 47 . Therefore, when the cassette 20 is used repeatedly, the staining liquid adheres to the cassette 20 . In the smear sample preparation device 2 of the present embodiment, the interior of the cassette 20 is washed by dispensing methanol into the cassette 20 in a process separate from the staining process.
In this case, the empty cassette 20 housed in the cassette receiver 47 is transported to the staining unit 50 . At position Mp, methanol is dispensed into the cassette 20 by the dispensing pipette Ma, and at position D 1 p the methanol in the cassette 20 is recovered by the recovery pipette D 1 p . Hence, the staining liquid adhered within the cassette 20 is washed therefrom.
Note that in the washing process for the interior of the cassette 20 only dispensing of the methanol by the dispensing pipette Ma and the recovery of the methanol by the recovery pipette D 1 b are performed. That is, the cassette 20 is moved backward without being stopped by the stopper at positions D 2 p , D 3 p , and Wp.
In the washing process of the cassette 20 , the liquid surface of the methanol dispensed into the cassette 20 by the dispensing pipette Ma is the same height as the liquid surface of the methanol dispensed into the cassette 20 by the dispensing pipette Ma in the staining process. That is, the amount of methanol dispensed for the washing process of the interior of the cassette 20 is a volume just sufficiently greater for the immersion of the slide glass 10 than the amount of methanol dispensed into the cassette 20 in the staining process. Hence, washing is reliably performed since the methanol is in contact with the staining liquid adhering to the interior of the cassette 20 while washing the cassette 20 .
FIG. 5 briefly shows a fluid circuit diagram of the smear sample preparation device 2 .
The smear sample preparation device 2 has flow passes formed so as to connect the first staining liquid chamber 121 , second staining liquid chamber 122 , staining liquid chamber 131 , diluting liquid chamber 143 , first mixing chamber 151 , second mixing chamber 152 , and discard chamber 165 in addition to the bottles 101 through 104 , first methanol chamber 111 and second methanol chamber 112 shown in FIG. 1 . Note that although the wash water bottle 105 , dispensing pipette Wa, recovery pipette Wb and their corresponding flow passes are illustrated, they are omitted in FIG. 5 for convenience.
As shown in the drawing, valves v 11 through v 17 , v 18 a , v 18 b , v 19 , v 20 through v 28 , v 20 a , v 29 b , v 30 a , v 30 b , v 31 through v 34 , v 35 a , v 35 b , v 41 a through v 43 a , v 41 b through v 43 b , v 51 a , v 51 b , v 52 a , v 52 b , and v 53 through v 56 are connected to the flow pass. The staining liquid and the like is allowed to flow or is blocked via the valves which are set to either an open state or a closed state. Pressure regulators 113 through 115 , 123 through 125 , 127 , 132 , 133 , 141 , 146 , 161 , 163 , 166 for regulating pressure, and diaphragm pumps 116 , 126 , 128 , 134 , 142 , 145 , 147 , 162 , and 164 which function to aspirate or discharge a set amount of staining liquid or the like are connected to the flow pass as shown in the drawing.
Referring to FIG. 6 , the first methanol chamber 111 is configured by a tank 111 b provided with an internal float switch 111 a . The float switch 111 a is configured by a float member 111 c , and a support rod 111 d for supporting the float member 111 c so as to be movable in vertical directions. A magnet 111 e is embedded within the float member 111 c . The float member 111 c moves vertically according to the liquid surface within the tank 111 b , and the magnet 111 e is positioned at the height of the liquid surface. A magnetic sensor type reed switch 111 f is embedded at a predetermined position (hereinafter referred to as “standard position”) in the vertical direction of the support rod 111 d.
The reed switch is turned on when the surface of the liquid within the tank 111 b is positioned at the standard position. The reed switch is turned off when the surface of the liquid in the tank 111 b is not at the standard position. Hence, it is possible to determine whether a predetermined amount of methanol is retained in the first methanol tank 111 .
Note that the second methanol chamber 112 , first staining liquid chamber 121 , second staining liquid chamber 122 , staining liquid chamber 131 , diluting liquid chamber 143 , and discard chamber 165 have the same structure as the first methanol chamber 111 , and are provided with an internal float switch. The standard amount of liquid retained in each chamber, is set individually, and the standard position at which the reed switch is in the turned on state is set individually in accordance therewith.
Returning to FIG. 5 , when supplying methanol from the bottle 101 to the first methane chamber 111 , the valves v 12 through v 16 are closed and valve v 11 is open. In this state, a vacuum is created within the first methanol chamber 111 by the pressure regulator 113 . Hence, the methanol retained in the bottle 101 is supplied into the first methane chamber 111 .
When supplying methanol from the bottle 101 to the second methanol chamber 112 , the valves v 11 , v 13 , v 17 , and v 19 are closed and valve v 12 is opened. In this state, there is a vacuum created within the second methanol chamber 112 by the pressure regulator 114 . Hence, the methanol retained in the bottle 101 is supplied into the second methane chamber 112 .
When the methanol retained in the first methanol chamber 111 is dispensed from the dispensing pipette Ma to the cassette 20 , valves v 11 , v 14 , v 15 , v 17 , and v 18 b are closed and valves v 16 and v 18 a are opened. In this state, there is a vacuum created within the diaphragm pump 116 by the pressure regulator 115 . Hence, a fixed amount of the methanol retained in the first methanol chamber 111 is aspirated into the diaphragm pump 116 . Then, the valve v 18 a is closed and the valve 18 b is opened. In this state, a positive pressure is created within the diaphragm pump 116 by the pressure regulator 115 . Hence, the methanol within the diaphragm pump 116 is dispensed from the dispensing pipette Ma to the cassette 20 .
When the methanol retained in the second methanol chamber 112 is dispensed from the dispensing pipette Ma to the cassette 20 , valves v 12 , v 16 , v 18 b , and v 19 are closed and valves v 17 and v 18 a are opened. In this state, there is a vacuum created within the diaphragm pump 116 by the pressure regulator 115 . Hence, a fixed amount of the methanol retained in the second methanol chamber 112 is aspirated into the diaphragm pump 116 . The methanol in the diaphragm pump 116 is then dispensed from the dispensing pipette Ma to the cassette 20 in the same way as the case of the first methanol chamber 111 .
When recovering the methanol retained in the cassette 20 in the first methanol chamber 111 via the recovery pipette D 1 b , the valves v 11 , v 14 , v 16 are closed and the valve 15 is opened. In this state, a vacuum is created within the first methanol chamber 111 by the pressure regulator 113 . Hence, the methanol aspirated from the recovery pipette D 1 b is recovered in the first methanol chamber 111 .
When discharging the methanol retained in the first methanol chamber 111 , the valves v 11 , v 15 , v 16 are closed and the valve v 14 is opened. In this state, the pressure is increased within the first methanol chamber 111 by the pressure regulator 113 . Hence, the methanol retained in the first methanol chamber 111 is discharged therefrom.
Next, when supplying the May-Grünewald solution as a staining liquid from the bottle 102 to the first staining liquid chamber 121 , the valves v 22 through v 24 , v 26 , and v 27 are closed and the valves v 20 and v 21 are opened. In this state, a vacuum is created within the first staining liquid chamber 121 by the pressure regulator 123 . Hence, the May-Grünewald solution retained within the bottle 102 is supplied to the first staining liquid chamber 121 .
When supplying May-Grünewald solution from the bottle 102 to the second staining liquid chamber 122 , the valves v 21 , v 23 , v 25 , and v 28 are closed and the valves v 20 and v 22 are opened. In this state, a vacuum is created within the second staining liquid chamber 122 by the pressure regulator 124 . Hence, the May-Grünewald solution retained within the bottle 102 is supplied to the second staining liquid chamber 122 .
When the May-Grünwald solution retained in the first staining liquid chamber 121 is dispensed from the dispensing pipette D 1 a to the cassette 20 , the valves v 21 , v 24 , v 26 , v 28 , v 29 b , and v 30 a are closed and the valves v 27 and v 29 a are opened. In this state, there is a vacuum created within the diaphragm pump 126 by the pressure regulator 125 . Hence, a fixed amount of the May-Grünewald solution retained in the first staining liquid chamber 121 is aspirated into the diaphragm pump 126 . Then, the valve v 29 a is closed and the valve v 29 b is opened. In this state, pressure is increased within the diaphragm pump 126 by the pressure regulator 125 . Hence, the May-Grünewald solution within the diaphragm pump 126 is dispensed from the dispensing pipette D 1 a to the cassette 20 .
When the May-Grünewald solution retained in the second staining liquid chamber 122 is dispensed from the dispensing pipette D 1 a to the cassette 20 , the valves v 22 , v 25 , v 27 , v 28 , v 29 b , and v 30 a are closed and the valves v 28 and v 29 a are opened. In this state, there is a vacuum created within the diaphragm pump 126 by the pressure regulator 125 . Hence, a fixed amount of the May-Grünewald solution retained in the second staining liquid chamber 122 is aspirated into the diaphragm pump 126 . The May-Grünewald solution in the diaphragm pump 126 is then dispensed from the dispensing pipette D 1 a to the cassette 20 in the same way as the case of the first staining liquid chamber 121 .
When recovering the May-Grünewald solution retained in the cassette 20 in the first staining liquid Chamber 121 via the recovery pipette D 2 b , the valves v 21 , v 24 , v 27 are closed and the valve v 26 is opened. In this state, a vacuum is created within the first staining liquid chamber 121 by the pressure regulator 123 . Hence, the May-Grünewald solution aspirated from the recovery pipette D 2 b is recovered in the first staining liquid chamber 121 .
When supplying the May-Grünewald solution retained in the first staining liquid chamber 121 to the first mixing chamber 151 , the valves v 21 , v 24 , v 26 , v 28 , v 29 a , and v 30 b are closed and the valves v 27 and v 30 a are opened. In this state, there is a vacuum created within the diaphragm pump 128 by the pressure regulator 127 . Hence, a fixed amount of the May-Grünewald solution retained in the first staining liquid chamber 121 is aspirated into the diaphragm pump 128 . Then, the valve v 30 a is closed and the valve v 30 b is opened. In this state, pressure is increased within the diaphragm pump 128 by the pressure regulator 127 . In this way the May-Grünewald solution within the diaphragm pump 128 is supplied to the first mixing chamber 151 . Note that an opening is provided in the first mixing chamber 151 to equalize the pressure within the chamber with the ambient pressure outside.
When supplying the May-Grünewald solution retained in the second staining liquid chamber 122 to the first mixing chamber 151 , the valves v 22 , v 25 , v 27 , v 29 a , and v 30 b are closed and the valves v 28 and v 30 a are opened. In this state, there is a vacuum created within the diaphragm pump 128 by the pressure regulator 127 . Hence, a fixed amount of the May-Grünewald solution retained in the second staining liquid chamber 122 is aspirated into the diaphragm pump 128 . The May-Grünewald solution in the diaphragm pump 128 is then supplied to the first mixing chamber 151 in the same way as the case of the first staining liquid chamber 121 .
When discharging the May-Grünewald solution retained in the first staining liquid chamber 121 , the valves v 21 , and v 25 through v 27 are closed and the valve v 24 is opened. In this state, the pressure is increased within the first staining liquid chamber 121 by the pressure regulator 123 . Hence, the May-Grünewald solution retained in the first staining liquid chamber 121 is discharged.
When discharging the May-Grünewald solution retained in the second staining liquid chamber 122 , the valves v 22 , v 24 and v 28 are closed and the valve v 25 is opened. In this state, the pressure is increased within the second staining liquid chamber 122 by the pressure regulator 124 . Hence, the May-Grünewald solution retained in the second staining liquid chamber 122 is discharged.
Similarly, by controlling the corresponding valves, pressure regulator and diaphragm pump, the Giemsa solution (staining liquid) is supplied from the bottle 103 to the staining solution chamber 131 Giemsa solution retained in the staining liquid chamber 131 is supplied to the second staining chamber 152 , phosphate buffer solution (diluting liquid) is supplied from the bottle 104 to the diluting liquid chamber 143 , diluting liquid retained in the diluting liquid chamber 143 is supplied to the first mixing chamber 151 , and diluting liquid retained in the diluting liquid chamber 143 is supplied to the second mixing chamber 152 .
In the first mixing chamber 151 , the May-Grünewald solution supplied from the first staining liquid chamber 121 or the second staining liquid chamber 122 is mixed with the diluting liquid supplied from the diluting liquid chamber 143 . Hence, a May-Grünwald dilute solution is produced within the first mixing chamber 151 . In the second mixing chamber 152 , the Giemsa solution supplied from the staining liquid chamber is mixed with the diluting liquid supplied from the diluting liquid chamber 143 . Hence, a Giemsa dilute solution is produced within the second mixing chamber 152 .
By controlling the corresponding valves, pressure regulator and diaphragm pump, the Giemsa solution retained in the staining liquid chamber 131 is dispensed from the dispensing pipette D 2 a to the cassette 20 , and Giemsa dilute solution retained in the second mixing chamber 152 is dispensed from the dispensing pipette D 3 a to the cassette 20 . The May-Grünewald dilute solution retained in the cassette 20 is recovered in the discard chamber 165 via the recovery pipette D 3 b , the May-Grünewald dilute solution retained in the first mixing chamber 151 is supplied to the discard chamber 165 , and the Giemsa dilute solution retained in the second mixing chamber 152 is supplied to the discard chamber 165 . The staining solution and the like retained in the discard chamber 165 is discharged therefrom by controlling the valves v 53 through v 56 and the pressure regulator 166 .
Note that the Giemsa dilute solution retained in the cassette 20 is recovered similar to the above through the recovery pipette Wb via chamber, diaphragm pump, and valves not shown in the drawings. The washing water retained in the bottle 105 is similarly dispensed to the cassette 20 through the dispensing pipette Wa and recovered through the recovery pipette Wb via chamber, diaphragm pump, and valves not shown in the drawing.
Thus, the staining liquid and the like accommodated in the bottles 101 through 105 can be dispensed to the cassette 20 through the flow pass by the dispensing pipettes Ma, D 1 a through D 3 a , and Wa. The staining liquid and the like aspirated by the recovery pipettes Wb and D 1 b through D 3 b can be recovered in the corresponding chambers through the flow pass. The staining liquid and the like retained in each chamber also can be discharged through the flow pass.
FIG. 7 briefly shows a the structures of the smear sample preparation device 2 and the transport device 3 .
The smear sample preparation device 2 is provided with a controller 201 , memory unit 202 , drive unit 203 , sensor unit 204 , fluid transporter 205 , communication unit 206 , and operation display unit 2 a.
The controller 201 controls the parts of the smear sample preparation device 2 by executing a computer program stored in the memory unit 202 . The memory unit 202 is a memory device such as a hard disk and the like, and stores a computer program for operating the smear sample preparation device 2 .
The memory unit 202 stores a reuse counter Rk for indicating the frequency of methanol reuse, a threshold frequency R 0 for indicating the upper limit reuse frequency, a recovery counter Ck for indicating the methanol recovery frequency, and a threshold frequency C 0 for indicating the upper limit of the recovery frequency, which will be described later. These frequencies are described later with reference to FIGS. 10( b ), 12 ( b ), and 14 .
The drive unit 203 includes an aspirating/dispensing mechanism 41 , slide glass supplier 42 , slide glass cross-feeder 43 , smearing mechanism 44 , smear drier 45 , printer 46 , cassette receiver 47 , cassette cross-feeder 48 , cassette rotator 49 , staining unit 50 , and cassette storage unit 51 , and a mechanism for driving each part within the smear sample preparation device 2 , and is controlled by the controller 201 .
The sensor unit 204 includes a sensor Ms for the methanol processing unit M, sensors D 1 s through D 3 s for the stain processing units D 1 through D 3 , and sensor Ws for the wash processing unit W. The sensor unit 204 includes a reed switch 111 f for the first methanol chamber 111 , and similar reed switches disposed in the other chambers. Each sensor included in the sensor unit 204 is controlled by the controller 201 , and the detection signals of the sensor unit 204 are output to the controller 201 .
The liquid transporter 205 includes pressure regulators 113 through 115 , 123 through 125 , 127 , 132 , 133 , 141 , 144 , 146 , 161 , 163 , 166 , and valves v 11 through v 17 , v 18 a , v 18 b , v 10 , v 20 through v 28 , v 29 a , v 29 b , v 30 a , v 30 b , v 31 through v 34 , v 35 a , v 35 b , v 41 a through v 43 a , v 41 b through v 43 b , v 51 a , v 51 b , v 52 a , v 53 b , v 53 through v 56 . The parts included in the liquid transporter 205 are controlled by the controller 201 .
The operation display unit 2 a is a touch panel with integrated input and display functions, as shown in FIG. 1 . When the user operates the operation display unit 2 a , a signal indicting the operation content is output to the controller 201 . The controller 201 displays each type of information on the operation display unit 2 a . The communication unit 206 performs data communication with the communication unit 304 of the transport device 3 .
The transport device 3 is provided with a controller 301 , drive unit 302 , sensor unit 303 , and communication unit 304 . The controller 301 controls the parts within the transport device 3 . The drive unit 302 includes mechanism for driving each part in the transport device 3 , and is controlled by the controller 301 . The sensor unit 303 includes sensors in the transport device 3 , is controlled by the controller 301 , and the detection signal of the sensor unit 303 is output to the controller 301 . The communication unit 304 performs data communication with the communication unit 206 of the smear sample preparation device 2 .
FIG. 8 is a flow chart showing the processes of the smear sample preparation device 2 .
The controller 201 executes processes corresponding to the pressed button when the user presses any of the buttons including the smear sample preparation start button 401 , cassette washing start button 402 , or shutdown start button 501 .
FIG. 9( a ) shows the start setting screen 400 displayed on the operation display 2 a . The smear sample preparation start button 401 and the cassette washing start button 402 are displayed on the start setting screen 400 . FIG. 9( b ) shows the shutdown setting screen 500 displayed on the operation display 2 a . The shutdown start button 501 is displayed on the shutdown start setting screen 500 . Note that the user can suitably display the start setting screen 400 and the shutdown setting screen 500 by operating the operation display unit 2 a.
Returning to FIG. 8 , when the controller 201 determines that the smear sample preparation start button 401 has been pressed (step S 11 : YES), the smear sample preparation process is executed (S 12 ). When the controller 201 determines that the cassette washing start button 402 has been pressed (step S 12 : N 0 , S 13 : YES), the cassette washing process is executed (S 12 ). When the controller 201 determines that the shutdown start button 501 has been pressed (S 11 : N 0 , S 13 : N 0 , S 15 : YES), the shutdown process is executed for the smear sample preparation device 2 . The smear sample preparation process and the cassette washing process are described below referring to FIGS. 10( a ) and 12 ( a ). Note that the controller 201 displays the message “Smear sample preparation process is executing” is displayed on the operation display unit 2 a while the smear sample preparation process (S 12 ) is being performed. On the other hand, that the controller 201 displays the message “Cassette washing process is executing” is displayed on the operation display unit 2 a while the cassette washing process (S 14 ) is being performed. Hence, the operator and others can readily comprehend whether the device is currently performing a process by confirming the indication on the operation display unit 2 a of the smear sample preparation device 2 .
Selection of the cassette wash start button 402 is disabled while the smear sample preparation process (S 12 ) is being performed after selecting the smear sample preparation start button 401 . On the other hand, selection of the smear sample preparation start button 401 is disabled while the cassette washing process (S 14 ) is being performed after selecting the cassette wash start button 402 . Thus, mixing of washed cassettes 20 and cassettes 20 with adhered staining liquid in the cassette storage unit 51 can be prevented by not interrupting an ongoing process with another process. Suspending a process through operation error also is prevented.
FIG. 10( a ) is a flow chart showing the smear sample preparation process.
The controller 201 aspirates the sample positioned in front of the hand unit 41 a (refer to FIG. 1 ) and performs the smear process (S 121 ). That is, the controller 201 prepares a smear sample from the aspirated sample, houses the smear sample in the cassette 20 , and positions the cassette 20 at the position Mp. The controller 201 then performs the staining process on the cassette 20 positioned at the position Mp via the staining unit 50 , and transports the cassette 20 to the cassette storage unit 51 .
The controller 201 then determines whether the smear preparation (S 121 , S 122 ) has been completed for all samples (S 123 ). When smear preparation of all samples is not complete (S 123 : NO), the controller 201 returns the process to S 121 , and sequentially performs smear preparation for subsequent samples. When smear preparation for all samples is completed (S 123 : YES), the smear sample preparation process ends.
In the staining process of the present embodiment, methanol, which has been dispensed from the first methanol chamber 111 to the cassette 20 through the dispensing pipette Ma, is then recovered in the first methanol chamber 111 through the recovery pipette D 1 b , and reused for dispensing through the dispensing pipette Ma.
FIG. 10( b ) is a flow chart showing the methanol dispensing process in the staining process of the present embodiment.
When the dispensing process starts, the controller 201 awaits the arrival of the cassette 20 at the position Mp. When the cassette 20 arrives at the position Mp (S 201 : YES), the controller 201 dispenses methanol from the first methanol chamber 111 to the cassette 20 (S 202 ), and adds [1] to the reuse counter Rk (S 203 ). The reuse counter Rk is stored in the memory unit 202 and is reset during initial startup of the smear sample preparation device 2 . The controller 201 then determines whether the reuse counter Rk has attained a preset threshold frequency R 0 (S 204 ). The threshold frequency R 0 is stored in the memory unit 202 .
Note that the methanol dispensed to the cassette 20 is recovered from the cassette 20 to the first methanol chamber 111 at the position D 1 p . Therefore, as the dispensing process progresses, the methanol in the first methanol chamber 111 is gradually degraded. The methanol recovery process is described below referring to FIG. 13( a ).
When the reuse counter Rk has not attained the threshold frequency R 0 (S 204 : NO), the controller 201 returns the process to S 201 , and the process of S 201 and subsequent steps are repeated. Therefore, the methanol is dispensed from the first methanol chamber 111 to the cassette 20 until the reuse counter Rk reaches the threshold frequency R 0 . In the present embodiment, the threshold frequency R 0 is user settable. The threshold frequency R 0 is an indicator to replace the methanol in the first methanol chamber 111 with fresh methanol.
FIG. 11( a ) is a flow chart showing the process for setting the threshold frequency R 0 .
When the controller 201 receives a display instruction of the threshold frequency setting screen 600 from the user (S 301 : YES), the controller 201 displays the threshold frequency setting screen 600 on the operation display unit 2 a (S 302 ) (refer to FIG. 1 ).
FIG. 11( b ) shows the threshold frequency setting screen 600 displayed on the operation display unit 2 a . The threshold frequency setting screen 600 has an input field 601 , OK button 602 , and cancel button 603 . The input field 601 is an area capable of receiving numbers 1 to 20 input by the user. The input field 601 includes up and down buttons; when the user presses the up button, the number in the input field 601 is incremented, whereas the number in the input field 601 is decremented when the down button is pressed. Note that the number 20 is set as the default value in the threshold frequency R 0 .
When the user presses the OK button 602 (S 303 : YES), the controller 201 writes the numerical value entered in the input field 601 in the threshold frequency R 0 stored in the memory unit 202 (S 304 ) and the threshold frequency setting screen 600 closes; when the cancel button 603 is pressed (S 303 : NO, S 305 : YES), the value entered in the input field 601 is deleted and the threshold frequency setting screen 600 closes.
Returning to FIG. 10( b ), when the reuse counter Rk attains the threshold frequency R 0 (S 204 : YES), the controller 201 starts, in parallel with the dispensing process, a process for replacing the methanol in the first methanol chamber 111 with fresh methanol (S 205 ). When the replacement process of the first methanol chamber 111 ends, the controller 201 resets the reuse counter Rk (S 206 ) and returns the process to S 201 . Thus, a new dispensing process starts after the methanol replacement.
FIG. 12( a ) is a flow chart showing the cassette washing process.
When the cassette wash start button 402 of FIG. 9 is pressed, the controller 201 transports the cassette 20 held in the cassette receiver 47 toward the cassette storage unit 51 (S 141 ). At this time, the cassette 20 held in the cassette receiver 47 is transported forward by the belt 47 a and supported by the cassette support 48 a of the cassette cross-feeder 48 . The cassette 20 supported on the cassette support 48 a is positioned in front of the cassette rotator 49 . Here, the controller 201 determines whether a slide glass 10 is accommodated in the cassette 20 via the sensor 48 s (S 142 ).
When the cassette 20 does not contain a slide glass 10 (S 142 : YES), the controller 201 performs the washing process on the cassette 20 (S 143 ). That is, methanol is dispensed by the dispensing pipette Ma to the cassette 20 positioned at position Mp, and methanol is recovered by the recovery pipette D 1 b from the cassette 20 positioned at the position D 1 p as previously described. After the washing process ends, the washed cassette 20 is transported to the cassette storage unit 51 . When the cassette 20 contains a slide glass 10 (S 142 : NO), the washing process is not performed, and the cassette 20 is moved backward by the belt 50 b of the staining unit 50 to the cassette storage unit 51 .
The controller 201 then determines whether washing (S 141 through S 143 ) has been completed for all cassettes 20 (S 144 ). This determination is YES if a cassette 20 is detected by the sensor 47 , and this determination is NO is a cassette 20 is not detected. When washing of all cassettes 20 is not complete (S 144 : NO), the controller 201 returns the process to S 141 , and sequentially performs washing for subsequent cassettes 20 . When washing of all cassettes 20 is completed (S 144 : YES), the cassette washing process ends.
In the washing process of the present embodiment, methanol, which has been dispensed from the first methanol chamber 111 to the cassette 20 through the dispensing pipette Ma, is then recovered in the first methanol chamber 111 through the recovery pipette D 1 b , and reused for dispensing through the dispensing pipette Ma similar to the smear sample preparation process.
FIG. 12( b ) is a flow chart showing the methanol dispensing process in the washing process of the present embodiment.
When the dispensing process starts, the controller 201 awaits the arrival of the cassette 20 at the position Mp. When the cassette 20 arrives at the position Mp (S 401 : YES), the controller 201 dispenses methanol from the first methanol chamber 111 to the cassette 20 (S 402 ), and adds [1] to the reuse counter Rk (S 403 ). Note that when the cassette 20 washing operation started after the staining operation, the incrementation by S 403 was made on the reuse counter Rk incremented in S 403 of FIG. 10 b ). The controller 201 then determines whether the reuse counter Rk has attained a preset threshold frequency R 0 (S 204 ). The reuse counter Rk and the threshold frequency R 0 are the same as the Rk and R 0 used in the dispensing process of the staining process of FIG. 10( b ).
Note that, in this case also, the methanol dispensed to the cassette 20 is recovered from the cassette 20 to the first methanol chamber 111 at the position D 1 p . Therefore, as the dispensing process progresses, the methanol in the first methanol chamber 111 is gradually degraded. Recovery of the methanol is performed according to the recovery process of FIG. 13( a ).
When the reuse counter Rk has not attained the threshold frequency R 0 (S 404 : NO), the controller 201 returns the process to S 401 , and the process of S 401 and subsequent steps are repeated. Therefore, the methanol is dispensed from the first methanol chamber 111 to the cassette 20 until the reuse counter Rk reaches the threshold frequency R 0 .
When the reuse counter Rk attains the threshold frequency R 0 (S 404 : YES), the controller 201 starts, in parallel with the dispensing process, a process for replacing the methanol in the first methanol chamber 111 with fresh methanol (S 405 ), and starts the count of the recovery counter Ck (S 406 ). The recovery counter Ck is stored in the memory unit 202 . The methanol recovery process is described below referring to FIG. 14 . The counting process of the recovery counter Ck is described below referring to FIG. 13( b ).
Thereafter, the controller 201 awaits the arrival of the cassette 20 at the position Mp (S 407 ). When the cassette 20 arrives at the position Mp (S 407 : YES), the controller 201 dispenses methanol to the cassette 20 from the second methanol chamber 112 rather than from the first methanol chamber 111 . Hence, when the methanol replacement process starts, the methanol chamber used to dispense methanol to the cassette 20 is switched from the first methanol chamber 111 to the second methanol chamber 112 .
It is then determined whether the methanol replacement in the first methanol chamber 111 is complete (S 409 ). When the methanol replacement in the first methanol chamber 111 is not complete (S 409 : NO), the controller 201 returns the process to S 407 . Hence, the methanol is dispensed from the second methanol chamber 112 to the cassette 20 until the methanol replacement in the first methanol chamber 111 is completed. Note that the recovery process of FIG. 13( a ) is performed and the methanol from the cassette 20 is recovered to the first methanol chamber 111 even when methanol is dispensed from the second methanol chamber 112 . When the methanol replacement in the first methanol chamber 111 is completed (S 409 : YES), the controller 201 resets the reuse counter Rk (S 410 ), and returns the process to S 401 . Thus, a new dispensing process starts after the methanol replacement.
FIG. 13( a ) is a flow chart showing the methanol recovery process.
The controller 201 awaits the arrival of the cassette 20 at the position D 1 p (S 501 ). When the cassette 20 arrives at the position D 1 p (S 501 : YES), the controller 201 recovers the methanol from the cassette 20 to the first methanol chamber 111 (S 502 ). Then, the controller 201 determines whether the liquid surface of the first methanol chamber exceeds the standard position (S 503 ); when the liquid surface exceeds the standard position (S 503 : YES), the methanol is discharged from the first methanol chamber 111 until the liquid surface in the first methanol chamber 111 is at the standard position (S 504 ). Thereafter, the controller 201 returns to S 501 and awaits the arrival of the next cassette 20 at the position Dp 1 . Hence, methanol dispensed to the cassette 20 is recovered in the first methanol chamber 111 . The methanol in the second methanol chamber 112 is therefore maintained in a fresh unused condition.
FIG. 13( b ) is a flow chart showing the count process of the recover counter Ck.
When the recovery counter Ck count process starts in S 406 of FIG. 12( b ), the controller 201 resets the recovery counter Ck (S 511 ). When recovering the methanol from the cassette 20 in the first methanol chamber 111 via the process of FIG. 13( a ), the controller 201 adds [1] to the recovery counter Ck (S 513 ). The counting process is performed until the recovery counter Ck count process is canceled. Cancellation of the recovery counter Ck counting process is performed in S 602 of FIG. 14 .
FIG. 14 is a flow chart showing the methanol replacement process of the first methanol chamber 111 .
When the methanol replacement process starts in S 405 of FIG. 12 , the controller 201 waits for the recovery counter Ck to attain the threshold frequency C 0 (S 601 ). The threshold frequency C 0 is a value pre-stored in the memory unit 202 . When the recovery counter Ck attains the threshold frequency C 0 (S 601 : YES), the controller 201 cancels the count of the recovery counter Ck (S 602 ), discharges all methanol in the first methanol chamber 111 (S 603 ), and thereafter replenishes fresh methanol from the bottle 101 to the first methanol chamber 111 (S 604 ). Hence, the replacement process ends when the methanol is replenished in the first methanol chamber 111 until the liquid surface attains the standard position (S 605 : YES). The determination of S 409 of FIG. 12( b ) is therefore YES.
On the other hand, when the methanol is not replenished in the first methanol chamber 111 until the liquid surface reaches the standard position (S 605 : NO), the controller 201 alerts the user to replace the bottle 101 by a methanol replenishment error (S 606 ). This alert is accomplished, for example, by displaying an alert screen on the operation display unit 2 a (refer to FIG. 1 ). When a replenishment error is detected, transporting of the cassette 20 and dispensing of methanol to the cassette 20 are suspended.
Thereafter, the controller 201 awaits the replacement of the bottle 101 (S 607 ). When the error alert is received the user replaces the bottle 101 with a fresh bottle 101 and thereafter, when, for example, replacement completed input is entered from the screen of the operation display 2 a (S 607 : YES), the controller 201 replenishes the first methanol chamber 111 with fresh methanol from the new bottle 101 (S 608 ). Methanol replenishment is thus started.
When the methanol is not replenished in the first methanol chamber 111 until the liquid surface reaches the standard position (S 609 : NO), the controller 201 alerts the user of a bottle replacement error (S 611 ), and the controller 201 awaits proper installation of the new bottle 101 (S 607 ). On the other hand, when the methanol is replenished in the first methanol chamber 111 until the liquid surface reaches the standard position (S 609 : YES), the controller 201 cancels the replenishment error (S 610 ), and the replacement process ends. When a replenishment error is canceled, transporting of the cassette 20 and dispensing of methanol to the cassette 20 are restarted.
Note that in the replacement process of FIG. 14 , the methanol is discharged from the first methanol chamber 111 after the recovery counter Ck has attained the threshold frequency C 0 in S 601 without immediately discharging the methanol from the first methanol chamber 111 even when the methanol replacement process has started in S 405 of FIG. 12( b ). This is done to prevent recovery of repeatedly used methanol in the first methanol chamber 111 after the replacement with fresh methanol. That is, a plurality of cassettes 20 are usually present from the position Mp to the position D 1 p with the timing of starting the methanol replacement process in S 405 of FIG. 12( b ). The methanol degraded through repeated use is dispensed from the first methanol chamber 111 to these cassettes 20 . Therefore, it is not desirable to recover methanol to the first methanol chamber 111 after replacing the methanol from the cassettes 20 .
In the present embodiment, discharge and replenishment of the methanol is not performed for the first methanol chamber 111 immediately until the recovery counter Ck has attained the threshold frequency C 0 even though the methanol replacement process starts. The threshold frequency C 0 is set so that the cassette 20 that has been dispensed unused methanol from the second methanol chamber 112 in S 408 of FIG. 12( b ) reaches the position D 1 p with the timing of the completion of the methanol replacement.
Note that the threshold frequency C 0 is preset based on the time (immersion time) from the dispensing of the methanol to the cassette 20 at position Mp to the recovery of the methanol from the cassette 20 at position D 1 p . Therefore, recovery of pre-replacement degraded methanol in the first methanol chamber 111 immediately after methanol replacement is prevented by providing a time lag based on the threshold frequency C 0 until the methanol replacement process is performed for the first methanol chamber 111 .
FIG. 15 is a flow chart showing the methanol replenishment process of the first methanol chamber 111 and second methanol chamber 112 . The replenishment process is performed every time methanol is dispensed from the first methanol chamber 111 or second methanol chamber 112 to the cassette 20 . Note that the description of the methanol replenishment process for the first methanol chamber 111 is identical to the methanol replenishment process for the second methanol chamber 112 .
When the liquid surface in the first methanol chamber 111 falls below the standard position (S 701 : YES), the controller 201 supplies fresh methanol to the first methanol chamber 111 from the bottle 101 (S 702 ). Methanol replenishment is thus started.
When the methanol is replenished in the first methanol chamber 111 until the liquid surface attains the standard position (S 703 : YES), the replenishment process ends. On the other hand, when the methanol is not replenished in the first methanol chamber 111 until the liquid surface reaches the standard position (S 703 : NO), the controller 201 alerts the user to replace the bottle 101 by a methanol replenishment error (S 704 ). When a replenishment error is detected while washing a cassette, transporting of the cassette 20 and dispensing of methanol to the cassette 20 are suspended.
Thereafter, the controller 201 awaits the replacement of the bottle 101 (S 705 ). When the error alert is received the user replaces the bottle 101 with a fresh bottle 101 and thereafter, when, for example, replacement completed input is entered from the screen of the operation display 2 a (S 705 : YES), the controller 201 replenishes the first methanol chamber 111 with fresh methanol from the new bottle 101 (S 706 ). When the methanol is not replenished in the first methanol chamber 111 until the liquid surface reaches the standard position (S 707 : NO), the controller 201 alerts the user of a bottle replacement error (S 709 ), and the controller 201 awaits proper installation of the new bottle 101 (S 705 ). On the other hand, when the methanol is replenished in the first methanol chamber 111 until the liquid surface reaches the standard position (S 707 : YES), the controller 201 cancels the replenishment error (S 708 ), the process returns to S 701 and the next replenishment timing is awaited. When a replenishment error is canceled, transporting of the cassette 20 and dispensing of methanol to the cassette 20 are restarted.
FIG. 16 shows an example of the washing process.
As shown in FIG. 16( a ), while the methanol is being reused, the methanol is dispensed from the first methanol chamber 111 to the cassette 20 at position Mp, and methanol is recovered from the cassette 20 to the first methanol chamber 111 at position D 1 p . When the reuse counter Rk attains the threshold frequency R 0 , processes are started during replacement and methanol is dispensed from the second methanol chamber 112 to the cassette 20 at position Mp, and methanol is recovered from the cassette 20 to the first methanol chamber 111 at position D 1 p , as shown in FIG. 16( b ). At this time the is at most dl individual cassettes 20 present between the position Mp and the position D 1 p . This process is repeated until the recovery counter Ck attains the threshold frequency C 0 . During this time, when the methanol retained in the first methanol chamber 111 exceeds the standard position, the methanol is discharged from the first methanol chamber 111 as shown in FIG. 16( c ).
Thereafter, when the recovery counter Ck attains the threshold frequency C 0 , the methanol is discharged from the first methanol chamber 111 as shown in FIG. 16( d ). At this time methanol from the second methanol chamber 112 is dispensed to the cassette 20 at position Mp. Thereafter, when methanol is replenished to the first methanol chamber 111 to the standard position as shown in FIG. 16( e ), the process is switched during reuse and the process using the first methanol chamber is restarted as shown in FIG. 16( f ).
According to the present embodiment described above, washing of all cassettes 20 placed in the cassette receiver 47 is performed automatically by pressing the cassette wash start button 402 when the empty cassette 20 has been placed in the cassette receiver 47 . Therefore, the labor required to wash the cassette 20 is greatly reduced.
According to the present embodiment, the cassette 20 washing process is skipped when a slide glass 10 is detected in the cassette 20 via the sensor 48 s during the cassette washing process. Therefore, washing a cassette 20 without removing the slide glass after preparing the smear sample can be avoided even when the cassette 20 is placed in error in the cassette receiver 47 .
According to the present embodiment, during the washing process the methanol dispensed to the cassette 20 is recovered through the recovery pipette D 1 b and the methanol of the first methanol chamber 111 is reused. Thus, the consumption of methanol is reduce compared to when methanol is discarded with each washing. This also reduces the environmental burden.
Although described in terms of the present embodiments, the present invention is not limited to these embodiments.
For example, although a single slide glass 10 (smear sample) is accommodated in a single cassette 20 in the above embodiment, the present invention is not limited to this arrangement inasmuch as a plurality of slide glasses 10 (smear samples) also may be accommodated.
Although another process cannot be performed while one of the smear sample preparation process (S 12 ) and cassette washing process (S 14 ) is being performed in the present embodiments, the present invention is not limited to this configuration inasmuch as another process may be performed through an interrupt while performing one process. For example, the smear sample preparation process may be performed through an interrupt even during an ongoing cassette washing process. In this case, a sample can be rapidly prepared when an urgent sample preparation is required during an ongoing cassette washing process.
In the above embodiments, the process of replacing the first methanol chamber 111 is started when the methanol reuse frequency (reuse counter Rk) attains a preset frequency (threshold frequency R 0 ) while methanol is reused (S 107 of FIG. 8 ). When the liquid surface of the first methanol chamber 111 is below a standard position while methanol is being reused, methanol is resupplied to the first methanol chamber 111 until the liquid surface attains the standard level (S 402 of FIG. 12 ). However, the present invention is not limited to this configuration inasmuch as methanol replenishment need not be performed when the liquid surface of the first methanol chamber 111 is below the standard position while methanol is being reused. In this case, the process for replacing the first methanol chamber 111 may be performed based on the amount of remaining methanol in the first methanol chamber 111 and need not be performed in accordance with the methanol reuse frequency (reuse counter Rk).
Although the connection of the flow passes shown in FIG. 5 are switched by valves in the above embodiments, the present invention is not limited to this configuration inasmuch as syringe pumps may be respectively provided to the flow passes to switch the connections of the flow passes by switching the actuation of the syringe pumps.
Although the methanol recovered from the cassette 20 through the recovery pipette D 1 b is moved to the first methanol chamber 111 in the above embodiments, the present invention is not limited to this configuration inasmuch as the recovered methanol also may be moved to a chamber other than the first methanol chamber 111 . In this case, the methanol moved to another chamber also may be reused. The recovered methanol also may be recovered in the discard chamber 165 so as to be discharged from the smear sample preparation device 2 .
Although dispensing and recovery of the methanol to/from the cassette 20 is performed once each in the cassette washing process of the above embodiments, the present invention is not limited to this configuration inasmuch as dispensing and recovery may be performed a plurality of times. The cassette 20 containing the methanol also may be shaken in the cassette washing process. Shaking the cassette 20 may be performed by, for example, moving the belt 50 b forward and back, or changing the lateral height of the belt 50 b via another mechanism. Methanol in the cassette 20 also may be caused to flow in the cassette washing process. The flow of the methanol may be induced by, for example, repeatedly dispensing and discharging the methanol in the cassette 20 via the recovery pipette D 1 b at position D 1 p . This operation reliably washes the cassette 20 .
Although methanol is used to fix the sample when washing the cassette 20 in the above embodiments, the present invention is not limited to this configuration inasmuch as a washing liquid other than methanol (for example, water) also may be used. Note that when was is used as the washing liquid, it is preferable to perform a process to dry the interior of the cassette 20 after the water is recovered from the cassette 20 .
Although the cassette 20 is moved to the positions Mp and D 1 p by the belt 50 b in the above embodiments, the present invention is not limited to this configuration inasmuch as the dispensing and recovery of methanol also may be performed while the cassette 20 is positioned at a predetermined position. In this case, for example, a pipette for dispensing methanol and a pipette for recovering methanol may be moved to the position of the cassette 20 and dispensing and discharge of the methanol may be performed at that position.
Although the same threshold frequency R 0 is used in the staining process and the washing process in the above embodiments, the present invention is not limited to this configuration inasmuch as different threshold frequencies also may be used. In this case, tolerance ranges can be set relative to the degrading of the reused methanol for both the staining process and the washing process, respectively. For example, a lower threshold frequency may be set for the washing process than for the staining process. In this case, the washing process is performed with less degraded methanol.
Note that, in the above embodiments, when the washing operation is started after the staining operation, the incrementation by S 403 was made on the reuse counter Rk incremented in S 403 of FIG. 10 b ). However, the present invention is not limited to this configuration inasmuch as the washing operation may be started after the methanol in the first methanol chamber 11 has been replaced with fresh methanol and the reuse counter Rk has been reset.
Although the smear sample preparation process is performed when a user presses the sample preparation start button 401 ( FIG. 9( a )) in the above embodiments, the present invention is not limited to this configuration inasmuch as the process also may be performed when the smear sample preparation device 2 receives a smear sample preparation instruction. For example, the clinical sample processing apparatus 1 of the above embodiment may be used as part of a sample processing system that includes a plurality of analyzers and a transport controller for controlling transport. In this case, the smear sample preparation process also may be performed when the controller 201 of the smear sample preparation device 2 receives a smear sample preparation instruction from the transport controller, or when the controller 201 receives a smear preparation instruction sent from the transport controller via the transport device 3 .
Although the above embodiments are configured to display a sample preparation start button and a cassette wash start button as software keys on the display unit, these buttons also may be implemented as hardware keys on the device.
The embodiments of the present invention may be variously and appropriately modified insofar as such modification is within the scope of the meaning expressed in the claims.
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A slide processing apparatus is disclosed. The apparatus comprise a liquid transporter for transporting a staining liquid reserved in a first liquid container and a washing liquid reserved in a second liquid container; a first instruction receiver for receiving a first instruction that instructs to initiate preparation of a slide stained with the staining liquid; a second instruction receiver for receiving a second instruction that instructs to initiate washing of a housing element which accommodates therein a slide to be stained; and a controller. When receiving the first instruction, the controller performs staining of the slide accommodated in the housing element by causing the liquid transporter to transport the staining liquid into the housing element. When receiving the second instruction, the controller performs washing of the housing element by causing the liquid transport to transport the washing liquid into the housing element.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a handrail for escalators or moving walkways with a grip piece of a thermoplastic elastomer with soft and hard segments, a handrail for escalators or moving walkways with a grip piece of a polymer material and a sliding layer made of a woven fabric with warp threads and weft threads and arranged thereon or connected thereto, extending at least in part over a lower surface—relative to the mounting orientation, and a method for producing handrails of this type.
[0003] 2. Description of Background and Other Information
[0004] Handrails for escalators, moving walkways, or similar applications are used as safety elements for passenger transport. For this purpose, the handrail must render possible a safe grip for the passenger and must withstand the dynamic loads or the environmental influences during operation without being damaged thereby. Handrails known from the prior art have a C-shaped cross section and are usually constructed from a plurality of different materials in order to meet these requirements. The handrail surface that can be touched by the passenger usually comprises an elastomer mixture. Furthermore, the handrail cover protects all of the components lying underneath from diverse environmental influences and must therefore be resistant thereto. To increase the dimensional stability of the handrail cross section, reinforcement inserts, e.g., fabric cords, are used. A sufficiently high lip rigidity, i.e., rigidity of the side areas of the handrail can also be achieved thereby.
[0005] The handrail is expected to retain its cross-sectional shape during its entire service life, i.e., the cross section must not be excessively enlarged or excessively reduced during its service life. In addition to a development of great noise, upon contact with the handrail track, the reduction would also lead to heat generation, to drive problems and ultimately to the destruction of the handrail. In turn, the result of an enlargement would be that, on the one hand, the passenger could become jammed between the handrail lip and the guide track and, on the other hand, that the handrail could jump out of the guide track.
[0006] Furthermore, to absorb longitudinal forces the handrail contains in its cross section so-called tensile carriers that must have a defined minimum breaking strength including in the impact area.
[0007] Finally, the so-called sliding layer forms the contact surface of the handrail to the handrail guide or to the handrail drive system.
[0008] Currently, essentially three materials are used in the handrail sector for moving walkways or escalators. On the one hand, this is a natural rubber or synthetic styrene butadiene rubber (SBR). Furthermore, there are handrails of Hypalon®, a chlorosulfonated polyethylene, and handrails of polyurethane on the market.
[0009] In addition, handrails have also already been described, which comprise at least in part a thermoplastic elastomer.
[0010] DE 197 42 258 A1 thus discloses a handrail for escalators and moving walkways with a grip piece of a polymer material, a reinforcing layer absorbing tensile forces, a layer for shape stabilization of textile layers arranged in the transverse direction and a finishing sliding layer. The layers are combined to form a textile structure in one piece and can be connected to the grip piece in a manufacturing operation. The grip piece itself can be made of a thermoplastic elastomer.
[0011] DE 198 32 158 A1 describes a handrail for an escalator or a moving walkway with a thermoplastic elastomer that preferably has at least a Shore hardness of 80 and preferably has a C-shaped profile. The inwardly facing surface of the handrail can comprise a section of a different material that preferably has a lower hardness than the rest of the handrail and that moreover is extruded. Ribs or grooves may be provided on the inwardly facing or drive surface of the handrail in order to vary the surface area of contact with the drive means. The use of the hard thermoplastic material to form the nose and the outer section of the handrail increases shape retention during extensive use and lowers the requirement for further reinforcement. The friction between the guide means on which the handrail travels is also reduced.
[0012] DE 299 03 376 U1 discloses a handrail for escalators and moving walkways that is produced (extruded) from a thermoplastic elastomer (TPE, TPO, TPU), preferably a thermoplastic polyurethane elastomer. A tensile carrier that is located in the center of the handrail is embodied as a roller chain with lateral bolts and can be clipped from below in a positive manner into a recess provided for this purpose. Hollow channels can be provided in the extruded profile, which channels help to save material as well as reducing the bending stiffness. Channels located to the right and to the left next to the tensile carrier recess can be provided on the underside of the handrail, in which channels the balustrade guide of the escalator runs. A thin-walled hose of ultra high molecular weight polyethylene (alternatively polytetrafluoroethylene) can be arranged therein, which hose is compressed when fixed onto the balustrade guide. The friction coefficient between guide and handrail and the abrasive wear are thereby reduced to a minimum.
[0013] Finally, handrails are also described, which comprise at least in part a thermoplastic material. For example, a handrail with a C-shaped profile is known from WO 00/01607 A, which handrail comprises a first layer of a thermoplastic material, a second layer of a likewise thermoplastic material, which second layer is arranged on the first layer and defines the outer surface of the hand rail, as well as a sliding layer that is arranged on the lower first thermoplastic layer. A tensile carrier is incorporated into the first layer and this first layer is of a harder thermoplastic material than the second layer.
SUMMARY OF THE INVENTION
[0014] The present invention is directed to a handrail with improved properties.
[0015] More particularly, the invention includes a handrail in which the grip piece comprises a thermoplastic elastomer in which the ratio of the proportions of soft segments to hard segments is selected, in a particular embodiment, from a range with a lower limit of 1:1 and an upper limit of 9:1. In another particular embodiment, the ratio of soft to hard segments is selected from a range with a lower limit of 1.5:1 and an upper limit of 6:1. In another particular embodiment, the ratio of soft to hard segments is selected from a range with a lower limit of 2.5:1 and an upper limit of 4:1. Further, the sliding layer of the handrail comprises weft threads and warp threads, the weft threads having a higher rigidity (modulus of elasticity) than the warp threads. Still further, the invention includes a method for producing a handrail of this type.
[0016] It is advantageous thereby that a handrail embodied in this manner, on the one hand, has a good tactile property and, on the other hand, the corresponding strength, so that it can be used if necessary without additional reinforcing elements. Handrails according to the invention show a good abrasion resistance, which is advantageous with respect to the constant contact with drive elements. Furthermore, the handrails according to the invention have a high service life despite the frequent negative and positive bending of the handrail. Moreover, only a very low, reversible, temperature-dependent change of length is present, so that handrails of this type also exhibit a good dimensional stability. Furthermore, through the greater rigidity of the weft threads of the fabric of the sliding layer a corresponding rigidity and thus in turn a dimensional stability of the handrail is achieved, the handrail in the longitudinal direction also having a corresponding flexibility, which is important for the bending behavior of the handrail.
[0017] To further improve these properties, it is advantageous if according to an embodiment the proportion of the hard segments is selected from a range with a lower limit of 10%, 15% in a variation, or 20%, in another variation, and an upper limit of 50%, or 40% in a variation, or 30% in another variation, and/or the proportion of the soft segments is selected from a range with an upper limit of 90%, or 85% in a variation, or 80% in another variation, and a lower limit of 70%, or 60% in a variation, or 50% in another variation, based on the total composition of the thermoplastic elastomer.
[0018] For the improvement of the ratio of rigidity to flexibility, it is possible according to a variant of the invention for the degree of crystallinity of the thermoplastic elastomer to be selected from a range with a lower limit of 10%, or 20% in a variation, or 25% in another variation, and an upper limit of 50%, or 40% in a variation, or 30% in another variation.
[0019] The thermoplastic elastomer can be a thermoplastic polyurethane block copolymer, at least comprising monomer units A and B, e.g., a diblock copolymer ([AB] n ), a triblock copolymer (A n -B m -A n ) a segment copolymer ([A a -B b ] n ) a star block copolymer ([A n -B m ] x X where x>2). It is advantageous thereby that a corresponding flexibility of the handrail is retained over a broad temperature range so that it can be assembled in the same manner all over the world, regardless of the place of use. Furthermore, a handrail of this type also exhibits a high wear resistance. The buckling resistance and breaking strength are likewise high and the dynamic loadability is also improved. A handrail of this type exhibits a good weather resistance as well as a resistance to oil, grease and solvents.
[0020] For the further improvement of these properties it is advantageous if the proportion of the monomer units B of the molecules of the soft segments in the polymer chain of the thermoplastic polyurethane is selected from a range with a lower limit of 20%, or 30% in a variation, or 35% in another variation, and an upper limit of 70%, or 60% in a variation, or 50% in another variation, based on the total mixture of soft and hard segments.
[0021] The soft segments can thereby be formed at least of one long-chain compound with at least two hydroxy groups, in particular a long-chain diol, such as a polyester diol and/or a polyether diol, with a relative molecular mass of 600 to 4000, the long-chain diol being selected in particular from a group comprising 1,4-bis(2-hydroxyethoxy)benzene[hydroquinone bis-(2-hydroxyethyl)ether], polytetrahydrofurane, poly(oxytetramethylene)glycol, poly(1,2-oxypropylene)glycol, poly(tetramethylene adipic acid)glycol, poly(ethylene adipic acid)glycol, poly(ε-caprolactam)glycol, poly(hexamethylene carbonate)glycol, polycaprolactone. Mixtures thereof, such as, e.g., 1,4-bis(2-hydroxyethoxy)benzene[hydroquinone bis-(2-hydroxyethyl)ether] and/or poly tetrahydrofurane and/or poly(oxytetramethylene)glycol and/or poly(1,2-oxypropylene)glycol and/or poly(tetramethylene adipic acid)glycol and/or poly(ethylene adipic acid)glycol and/or poly(ε-caprolactam)glycol and/or poly(hexamethylene carbonate)glycol and/or polycaprolactone with 1,4-bis(2-hydroxyethoxy)benzene[hydroquinone bis-(2-hydroxyethyl)ether] and/or poly tetrahydrofurane and/or poly (oxytetramethylene)glycol and/or poly(1,2-oxypropylene)glycol and/or poly(tetramethylene adipic acid)glycol and/or poly(ethylene adipic acid)glycol and/or poly (ε-caprolactam)glycol and/or poly(hexamethylene carbonate)glycol and/or polycarprolactone are likewise possible. The advantage is attained in particular with the polyether diols that a handrail made thereof shows an improved hydrolytic resistance and microbial resistance so that, if necessary, further additives for improving these properties can be omitted. It is furthermore advantageous thereby that the flexibility of the handrail can be varied through the use of the given compounds, so that different handrail lengths can be taken into account. It is advantageous thereby that the rigidity of the handrail does not fall below a predetermined measurement.
[0022] In order to obtain a desired ratio between flexibility and rigidity of the handrail, it is provided according to a further embodiment variant of the invention that the hard segments are formed by at least one short-chain compound with at least two hydroxyl groups, in particular a short-chain diol, with a relative molecular mass of 61 to 600, the short-chain diol being selected in particular from a group comprising 1,4-butanediol,1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 2,2-dimethyl-1,3-propanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol. Mixtures thereof, such as, e.g., 1,4-butanediol and/or 1,6-hexanediol and/or ethylene glycol and/or diethylene glycol and/or triethylene glycol and/or propylene glycol and/or dipropylene glycol and/or 2,2-dimethyl-1,3-propanediol and/or 1 , 10 decanediol, 1,4-cyclohexanedimethanol with 1,4-butanediol and/or 1,6-hexanediol and/or ethylene glycol and/or diethylene glycol and/or triethylene glycol and/or propylene glycol and/or dipropylene glycol and/or 2,2-dimethyl-1,3-propanediol and/or 1,10-decanediol and/or 1,4-cyclohexanedimethanol, are likewise possible.
[0023] The thermoplastic elastomer can be formed by reaction of the compound(s) comprising at least two hydroxy groups with at least one isocyanate from a group comprising aromatic isocyanates, in particular diisocyanates, such as, e.g., 4,4′-methylene diphenyl diisocyanate, 3,3′-dimethyl-4,4′-biphenyldiisocyant, 1,5-naphthalene-diisocyanate, toluoylene diisocyanate, aliphatic isocyanate, such as, e.g., 4,4′-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, hexamethylene diisocyanate-triisocyanurate, isophorone diisocyanate. The compound(s) comprising at least two hydroxy groups can be a polyol selected from a group comprising polyols based on polyadipates of short-chain diols with two functional hydroxy groups and 2 to 20 carbon atoms, e.g., polycaprolactones, polycarbonate diols and/or polyols with more than two free hydroxy groups, such as, e.g., pentaerythrite. The compound(s) comprising the at least two hydroxy groups can likewise be a polyol that has a relative molecular mass, selected from a range with a lower limit of 1000 and an upper limit of 2000. Mixtures of the cited compounds, such as, e.g., aromatic isocyanates, in particular diisocyanates, such as, e.g., 4,4′-methylene diphenyl-diisocyanate and/or 3,3′-dimethyl-4,4′-biphenyldiisocyant and/or 1,5-naphthalene-diisocyanate and/or toluoylene diisocyanate, aliphatic isocyanates, such as, e.g., 4,4′-dicyclohexylmethane diisocyanate and/or hexamethylene diisocyanate and/or hexamethylene diisocyanate-triisocyanurate and/or isophorone diisocyanate with at least one aromatic isocyanate, in particular diisocyanate, such as, e.g., 4,4′-methylene diphenyl-diisocyanate and/or 3,3′-dimethyl-4,4′-biphenyldiisocyanate and/or 1,5-naphthalene-diisocyanate and/or toluoylene diisocyanate and/or at least one aliphatic isocyanate, such as, e.g., 4,4′-dicyclohexylmethane diisocyanate and/or hexamethylene diisocyanate and/or hexamethylene diisocyanate-triisocyanurate and/or isophorone diisocyanate, or a polyol that has a relative molecular mass, selected from a range with a lower limit of 1000 and an upper limit of 2000, are also possible.
[0024] For the number of bonds, thus also for mechanical strength, it is advantageous if compound comprising at least two hydroxy groups has an acid number of less than 1 mg KOH/g compound.
[0025] In addition to embodying the grip piece as thermoplastic polyurethane it is also possible within the scope of the invention to form the handrail from a thermoplastic vulcanisate (TPE-V). It is thus possible to combine the properties of vulcanizable rubber with the easy processability of thermoplastic materials. A resistance to chemicals is achieved therewith that is comparable to chloroprene rubber mixtures, in particular for aqueous liquids, oil and hydrocarbons. An improved dynamic fatigue strengths are also achieved. The ozone resistance and weather resistance can also be improved.
[0026] The thermoplastic vulcanisate can be formed by an ethylene/propylene diene methylene (EPDM) polypropylene mixture, the EPDM proportion of the mixtures being selected according to an embodiment variant from a range with a lower limit of 20%, or 25% in a variation, or in 30% in another variation, and an upper limit of 45%, or 40% in a variation, 35%, or is selected pursuant to a further embodiment of the polypropylene proportion of the mixture from a range with a lower limit of 5%, or 7% in a variation, or 10% in another variation, and an upper limit of 25%, or 17% in a variation, or 15% in another variation. Depending on the embodiment of the EPDM/PP blends, i.e., mechanical EPDM/PP blend or EPDM/PP blend with partly crosslinked EPDM phase or highly crosslinked EPDM phase, the elongation at break can be adjusted to values from approx. 300 or 350% or for mechanical EPDM/PP blends values in the order of magnitude of 600% to 800% can be achieved. The breaking strength can be likewise varied in a corresponding manner, for example, between 5 MPa and 30 MPa.
[0027] In order to vary the handrail properties further or to produce special properties it is possible to add to the EPDM/PP mixture at least one further additive, selected from a group comprising softening agents, fillers, colorants, antibacterial active ingredients, crosslinking agents or mixtures thereof.
[0028] As mentioned above, it is possible with the handrail according to the invention to embody the grip piece in one layer, through which the production as well as the subsequent splice formation to join the handrail ends can be simplified accordingly, thus reducing the production costs.
[0029] It is thereby possible that at least one tensile carrier, for example, of steel, is embedded in the grip piece in order to render possible a higher longitudinal stability, i.e., a low variance of the change in length during the operation of the handrail. A correspondingly simpler structure is also possible by embedding in the grip piece.
[0030] Within the scope of the invention it is of course also possible to embody the grip piece in multiple layers if required and to embody at least several of the layers of optionally different thermoplastic elastomers in order to obtain a mix of properties, which cannot be achieved through one material.
[0031] It is advantageous thereby if the tensile carrier is embedded in an outer layer of the grip piece, which can make it possible to improve the flexibility of the handrail during bending.
[0032] It is further possible to embody the grip piece in at least two layers with a cover layer and a reinforcing layer arranged beneath it relative to the mounting orientation of the handrail, short fibers being embedded in the reinforcing layer. The handrail can thus be given an improved rigidity, wherein the tensile carrier can optionally be omitted. Furthermore, the production of the handrail is simplified, since the short fibers can already be added to the mixture for the handrail, i.e., the reinforcing layer, and this mixture can therefore be processed with conventional methods.
[0033] The short fibers can be formed by a material selected from a group comprising inorganic materials, such as, e.g., carbon, glass, metals or alloys, such as, e.g., steel, aluminum, copper, and organic materials, such as, e.g., synthetic fibers, e.g., of nylon, polyester, aromatic polyamides (Kevlar), or natural fibers, for example of cotton, cellulose fibers, viscose, and mixtures thereof, such as, e.g., inorganic materials, such as, e.g., carbon, and/or glass, and/or metals or alloys, such as, e.g., steel and/or aluminum and/or copper and/or organic materials, such as, e.g., synthetic fibers, for example of nylon and/or polyester and/or aromatic polyamides (Kevlar) and/or natural fibers, for example, of cotton and/or cellulose fibers and/or viscose with inorganic materials, such as, e.g., carbon and/or glass and/or metals or alloys, such as, e.g., steel and/or aluminum and/or copper and/or organic materials, such as, e.g., synthetic fibers, for example of nylon and/or polyester and/or aromatic polyamides (Kevlar) and/or natural fibers, for example, of cotton and/or cellulose fibers and/or viscose.
[0034] The reinforcing layer can be embodied to be interrupted in the longitudinal direction, wherein, if a tensile carrier is used in the handrail, it is advantageous in this case if this tensile carrier is arranged in the cover layer. Improved bending properties can be achieved by the interruption of the reinforcing layer.
[0035] Furthermore, it is possible that the reinforcing layer has at least approximately the same hardness as the cover layer, so as not to thus negatively influence the hardness of the entire handrail.
[0036] In a further embodiment of the sliding layer it is provided that the warp threads have an initial modulus of elasticity according to ASTM D 885, selected from a range with a lower limit of 4.5 GPa, or 5.0 GPa in a variation, or 5.3 GPa in another variation, and an upper limit of 12 GPa, or 10 GPa in a variation, or 9 GPa in another variation, through which the handrail can be given an improved longitudinal elasticity.
[0037] The warp threads can be formed by staple fibers, wherein these staple fibers can be selected according to an embodiment variant from a group of materials comprising polyamides, polyimides, in particular aromatic para-aramids, polyester, polyolefins, e.g., polypropylene and mixtures thereof, such as, e.g., polyamides and/or polyimides and/or in particular aromatic para-aramids and/or polyester and/or polyolefins, e.g., polypropylene, with polyamides and/or polyimides, in particular aromatic para-aramids and/or polyesters and/or polyolefins, e.g., polypropylene. The breaking strength of the warp threads can thus be improved.
[0038] On the other hand, it is also possible to form the warp threads from rubber threads, wherein the material compatibility to the material of the cover layer or the other layers of the handrail can be improved.
[0039] The weft threads can have a rigidity (modulus of elasticity) according to ASTM D 885, selected from a range with a lower limit of 6.0 GPa, or 7.0 GPa in a variation, or 8.0 GPa in another variation, and an upper limit of 175 GPa, or 165 GPa in a variation, or in 150 GPa in another variation, through which a high lip rigidity of the handrail is achieved and thus the lifting of the handrail from the balustrade or guide arrangement can be better prevented.
[0040] The weft threads can thereby be selected from a group of materials comprising polyamide, polyester, multifilament yarns, aramids or mixtures thereof, such as, e.g., polyamide and/or polyester and/or multifilament yarns and/or aramids with polyamide and/or polyester and/or multifilament yarns and/or aramids in order to improve these properties of the sliding layer for handrails.
[0041] The polymer material of the grip piece can be selected from a group of materials comprising thermoplastic elastomers, such as, e.g., TPU (thermoplastic polyurethane), TPV (thermoplastic vulcanisates), TPO (thermoplastic polyolefins) SBS or SIS or SBC (thermoplastic styrene triblock copolymers), TP-NR (thermoplastic natural rubber), TP-NBR (thermoplastic nitrile rubber), TP-FKM (thermoplastic fluorinated rubber), CPO or CPA (copolymer polyester), PEBA (polyether block amides), furthermore EPDM, natural rubber, CSM, CR (isoprene rubber), SBR (styrene-butadiene rubber), BR (butyl rubber), NBR (nitrile rubber), PU (polyurethane) and mixtures or blends thereof. The sliding layer can thus also be used for handrail materials already known.
[0042] It is advantageous thereby if the grip piece has a hardness according to Shore A, selected from a range with a lower limit of 55 ShA, or 63 ShA in a variation, or 70 ShA in another variation, and an upper limit of 50 ShD, or 45 ShD in a variation, or 40 ShD in another variation. In particular grip pieces of a thermoplastic elastomer can thereby have a hardness in the range of 40 ShD to 45 ShD and those of a cross-lined elastomer can have a hardness in the range between 60 ShA and 70 ShA.
[0043] It is thus also possible to form the grip piece in one layer with high strength of the handrail at the same time.
[0044] It is also advantageous if the sliding layer is embedded, at least in some areas, in particular the side areas thereof, into the grip piece in order to prevent the tear resistance of the delamination of the sliding layer as far as possible.
[0045] The handrail can be produced continuously through extrusion or, in the case of multiple layers, by means of coextrusion and or intermittently through stacking the individual layers and subsequently by press vulcanization, continuous methods being preferred within the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] The invention is described in more detail below based on the exemplary embodiments, illustrated in a very diagrammatically simplified manner in the following drawing figures, in which:
[0047] FIG. 1 is a section from a handrail in oblique view;
[0048] FIG. 2 shows the handrail according to FIG. 1 in cross section;
[0049] FIG. 3 shows another embodiment of a handrail in oblique view.
DETAILED DESCRIPTION OF THE INVENTION
[0050] In the differently described embodiments the same parts are provided with the same reference numbers or the same component designations, wherein the disclosures contained in the entire specification can be applied analogously to the same parts with the same reference numbers or the same component designations. The location data selected in the specification, such as, e.g., at the top, at the bottom, at the side, etc., also refer to the drawing figure directly described and shown and should be applied analogously to the new location in the event of a change in location. Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described can also represent per se independent, inventive solutions or solutions according to the invention.
[0051] All of the data regarding value ranges in this specification should be understood to include any and all partial ranges therefrom, e.g., in the specification 1 to 10 is to be understood in that all partial ranges, starting from the lower limit 1 and the upper limit 10 are included, i.e., all partial range begin with a lower limit of 1 or greater and end with an upper limit of 10 or below, e.g., 1 to 1.7, or 3.2 to 8.1 or 5.5 to 10.
[0052] FIG. 1 shows a handrail 1 for an escalator or a moving walkway. This handrail comprises a grip piece 2 , which faces the user of the escalator or moving walkway in the installed position of the handrail 1 . A tensile carrier 3 can be arranged in the grip piece 2 , which tensile carrier absorbs longitudinal forces that act on the handrail 1 , and thus prevents at least in part changes in the length of the handrail 1 . A sliding layer 4 is arranged on the underside of the handrail 1 , via which sliding layer the handrail 1 can be brought into engagement with guide devices, not shown, such as, for example, the balustrade of an escalator, as well as drive devices, which are known from the prior art.
[0053] The drive of the handrail 1 can be carried out in any desired manner, as already known from the prior art. Drive devices of this type are, e.g., reel drives, track drives, etc.
[0054] The tensile carrier 3 , as is known per se, can comprise a metal or of an alloy, e.g., of steel. Furthermore, the tensile carrier 3 can comprise individual wires or steel cables. It is likewise possible that the tensile carrier 3 is a continuous steel band or the like.
[0055] The sliding layer 4 usually comprises a fabric of threads and is used to reduce the friction between the handrail 1 and the guide device during the movement of the handrail to an extent that are necessary for the drive of the handrail 1 . In principle, the sliding layer 4 can be embodied according to the prior art, so that reference can be made to the relevant literature or according to the invention, as set forth below in more detail. The sliding layer 4 can be adhered to the grip piece 2 or connected to the grip piece 2 in a different manner, e.g., in that a rubber material is attached to the surface of the sliding layer 4 before it is installed and this rubber material is connected to the other layers of the handrail 1 during the production of the handrail, e.g., the vulcanization. It is likewise conceivable that if the handrail 1 is produced by an extrusion method, the sliding layer 4 is fed to the extruder and the grip piece 2 is extruded onto this sliding layer.
[0056] The sliding layer 4 , as can be seen better from FIG. 2 , extends into an outer lip area 5 of the grip piece 2 of the handrail 1 . However, it is also conceivable that the sliding layer 4 merely via a partial area of a recess 6 that is defined by the cross section of the handrail 1 and in the present exemplary embodiment of the invention, since the handrail has a C-shaped profile, is embodied in a T-shaped manner. For example, this sliding layer 4 can extend up to an inner edge 7 of the recess 6 , wherein the edge 7 can be located at a transition between an at least approximately horizontal area 8 of a lip 9 of the handrail 1 and an at least approximately vertical area 10 of an inner surface 11 of the handrail 1 .
[0057] Furthermore, it is possible that the sliding layer 4 is anchored with its lateral end areas in the grip piece 2 , i.e., projects into the grip piece 2 with these end areas, as indicated by broken lines in FIG. 2 .
[0058] According to the embodiment shown in FIGS. 1 and 2 , the grip piece 2 is embodied in one piece, i.e., in one layer. It is likewise possible within the scope of the invention to embody this grip piece in multiple layers with a reinforcing layer, as set forth in more detail below.
[0059] The grip piece 2 is produced from a thermoplastic elastomer. As known per se, thermoplastic elastomers are polymer materials that combine the properties of elastomers and the processing properties of thermoplastics. This is achieved in that soft and elastic segments with high expandability and low glass-transition temperature as well as hard, crystallizable segments with low expandability, high glass-transition temperature and tendency to form associates (physical crosslinking) are present at the same time in the macromolecules of the corresponding plastics. Usually the soft segments and hard segments are incompatible with one another and are present as individual phases. Thermolabile, reversibly fissile crosslink points, mostly of a physical but also of a chemical nature, are thus characteristic of thermoplastic elastomers. According to the invention, the proportions of the soft segments and hard segments are measured such that they are selected from the ranges given above. Handrails 1 can thus be produced in a relatively cost-effective manner with processing methods for thermoplastics, for example, extrusion or co-extrusion, which on the one hand have a sufficient rigidity, and on the other hand also render possible sufficient bending, in order to thus withstand undamaged over a long period the negative or positive bending normally occurring for handrails 1 in the area of the drives and deflections. Furthermore, through the soft segments a corresponding tactile quality is achieved that is comparable at least to that known from handrails of natural rubber.
[0060] Within the scope of the invention, thermoplastic polyurethanes (TPU) or thermoplastic vulcanisates (TPV) are particularly used as thermoplastic elastomers. However, it is also possible to use other thermoplastic elastomers, such as, e.g., styrene-based thermoplastic elastomers (SBS, SIS, SIBS), thermoplastic natural rubber (NR-TP), EVA/PVDC blends, NBR/PP blends, polyether ester, polyether aramides, olefin-based thermoplastic elastomers, thermoplastic nitrile rubber (TP-NBR), thermoplastic fluorinated rubber (TP-FKM), thermoplastic silicone rubber (TP-Q), copolymer polyether ester (CPE, CPA), polyether block aramides (PEBA), blends of crosslinked EPM or EPDM with polyolefins (TPO), blends of uncrosslinked EPM or EPDM in polyolefins (EPDM/PP).
[0061] A thermoplastic polyurethane according to the invention can comprise, e.g., short-chain diols with isocyantes for hard segments, long-chain polyester diols and/or polyether diols for the soft segments in the form of an [AB] n -block polymers. The short-chain diols can thereby have molecular masses M g in the range of 61 to approx. 600 (weight average), the long-chain diols can have molecular masses M n in the range between 600 and 4,000 (number average). However, polyols, in particular of the above-mentioned type with molecular masses between M g 1,000 and 2,000 (weight average) and/or an acid number <1 mg KOH/g polyol can also be used as hydroxyl compounds. For example, mixtures of long-chain polyols, diisocyanates and short-chain diols can thus be produced within the scope of the invention. In addition, this mixture can also contain further additives, for example, internal separating agents, montanic acid ester, silicones, aramide waxes, softening agents, in the event that the thermoplastic elastomer is to have a hardness of <70 ShA. Aromatic processing oils, naphthenic processing oils or paraffinic processing oils can be used as softening agents. Softening agents of this type are known to one skilled in the art working in this field, and reference is made here by way of example to the Association of the German Rubber Industry Guideline (W.d.K.-Leitlinie) (wdk) 1315, page 2, with respect to the specification.
[0062] The production of the thermoplastic polyurethanes can be carried out within the scope of the invention in a solvent-free manner, with an NCO/OH ratio that is stoichiometric in a particular embodiment, but no less than in approx. 0.95 or 0.97.
[0063] Other production methods are of course likewise within the scope of the invention, for example using solvents, etc.
[0064] In Table 1 below some exemplary formulas are given for thermoplastic polyurethanes that are used within the scope of the invention. The NCO/OH ratio of these seven mixtures lies in the range of between 1.01 and 1.05.
[0000]
TABLE 1
Parts by weight
Formula examples
No. 1
No. 2
No. 3
No. 4
No. 5
No. 6
No. 7
Poly(oxytetramethylene)glycol 2000
100.0
100.0
100.0
Poly(1,6-hexanediol carbonate)glycol
100.0
100.0
3000
Polycaprolacton glycol 2000
100.0
100.0
1,4-butanediol
6.5
2-ethyl-1,3-hexanediol
15.1
17.0
16.5
15.1
2,2,4-trimethylpentane-1,3-diol
15.1
15.1
Tinuvin B75
1.6
1.6
1.6
1.6
1.6
1.6
1.6
4,4′-diphenylmethanediisocyanate (MDI)
39.1
39.1
38.2
26.9
37.4
4,4′-dicyclohexylmethanediisocyanate
40.9
40.9
(H 12 -MDI)
[0065] With respect to the thermoplastic vulcanisates, such as EPDM/PP blends, are used and a composition are given to this end in Table 2 by way of example. A peroxidic resin crosslinking system can thereby be used as the crosslinking system.
[0000]
TABLE 2
Material 1
Material 2
Material 3
Material 4
60 A
62 A
70 A
60 A
Softening agent
39%
44%
31%
36%
(paraffinic)
EPDM
34%
32%
36%
30%
PP
13%
14%
16%
20%
Carbon black
—
3%
—
—
Light filler (kaolin)
11%
5%
15%
11%
Crosslinking system
3%
2%
2%
3%
[0066] The numerical data in the first line below the respective material hereby mean the hardnesses according to Shore A.
[0067] Exemplary formulas for further thermoplastic elastomers that can be used within the scope of the invention are given in Tables 4 through 8, wherein “phr” stands for “parts per hundred rubber.”
[0000]
TABLE 3
SBR/BR/NR
phr
%
SBR
40.0
18.3
BR
50.0
22.8
NR
10.0
4.6
Carbon black
75.0
34.2
Oil
17.0
7.8
TOR
10.0
4.6
Antiozonant
2.0
0.9
wax
ZnO
5.0
2.3
Stearic acid
1.0
0.5
Sulfur
2.0
0.9
TBBS
2.0
0.9
HMT
2.0
0.9
HPPD
2.0
0.9
TMQ
1.0
0.5
219.0
[0000]
TABLE 4
EPDM
PHR
%
EPDM
100.0
37.2
Carbon black
100.0
37.2
Oil
60.0
22.3
ZnO
5.0
1.9
Stearic acid
1.0
0.4
Sulfur
1.0
0.4
TMTD
1.2
0.4
MBT
0.8
0.3
269.0
[0000]
TABLE 5
CSM
PHR
%
CSM
100.0
45.7
Kaolin
80.0
36.5
MgO
4.0
1.8
Oil
30.0
13.7
Pentaerythritol
3.0
1.4
DPTT
2.0
0.9
219.0
[0000]
TABLE 6
NR/BR
PHR
%
NR
70.0
35.0
BR
30.0
15.0
Carbon black
50.0
25.0
Silica
20.0
10.0
Silane
1.0
0.5
Oil
15.0
7.5
6PPD
3.0
1.5
Antiozonant
2.0
1.0
wax
ZnO
5.0
2.5
Stearic acid
1.0
0.5
Sulfur
1.4
0.7
TBBS
1.8
0.9
200.2
[0000]
TABLE 7
NBR
PHR
%
NBR
100.0
46.6
Carbon black
70.0
32.6
Chalk
20.0
9.3
DOP
8.0
3.7
6PPD
3.0
1.4
Antiozonant
2.0
0.9
wax
ZnO
5.0
2.3
Stearic acid
1.0
0.5
Sulfur
0.4
0.2
TMTD
1.5
0.7
OTOS
2.5
1.2
CBS
1.0
0.5
214.4
[0068] These mixtures or the handrails 1 produced therefrom all show—more or less pronounced—positive properties, such as, e.g., a higher creep resistance, better elasticity, etc.
[0069] The invention is not restricted to the examples of the formulas given or the individual compounds given as preferred for producing these formulas, instead they are to be seen within the scope of the invention given in the claims for protection.
[0070] Further additives, such as, e.g., colorants, etc., can be added to all of the mixtures. Since the handrail 1 according to the invention comprises a thermoplastic elastomer, the splice formation, i.e., the connection of the two ends of the handrail 1 to form an endless belt, is simplified compared to the conventional splice forming methods in the field of natural rubber. For example, simple processing techniques from thermoplastic chemistry, for example, extrusion methods, can be used for this purpose. Likewise, a direct welding or adhesion of the two ends to one another is possible. The positioning of a connecting piece and its complex pattern embodiment for overlapping individual layers in order to produce a permanent connection may thus possibly be omitted.
[0071] In addition to the embodiment in one layer of the grip piece 2 , within the scope of the invention it is also possible to embody it, as already mentioned, in multiple layers, i.e., in at least two layers. According to the invention it can thereby be provided for a further layer to be arranged as a reinforcing layer beneath a first layer that faces the user of the escalator or moving walkway. Short fibers, as stated above, can be arranged in this reinforcing layer, wherein the orientation of these short fibers in the reinforcing layer is completely arbitrary, i.e., no preferred direction is prescribed. This means that at least one proportion of the short fibers will come to rest crosswise to the longitudinal extension or at an angle to the longitudinal extension of the handrail 1 , and thus the handrail 1 can be given a corresponding transverse rigidity, in particular also a lip rigidity. For this reason a majority of the short fibers is also arranged at an angle to the longitudinal extension of the handrail 1 . This second layer can thereby have the same hardness as the cover layer of the grip piece 2 . Other hardnesses are likewise conceivable, although layers of equal hardness are used in a particular embodiment. The layers of the grip piece 2 can be formed by different materials, in particular different thermoplastic elastomers, but the embodiment from the same elastomer is likewise also possible. A coextrusion method can be used to produce a multilayer handrail, wherein the short fibers have already been added to the plastic strand.
[0072] Furthermore, it is also possible that the cover layer, i.e., the outermost layer of the grip piece 2 , is drawn into the lip area, so that therefore the other layers or the inner layer is covered by the cover layer, therefore nothing can be seen from the outside of the inner layers thus produced, since these inner layers are covered on the underside by the sliding layer 4 .
[0073] In an embodiment variant in the case of the multilayer structure of the handrail 1 , i.e., of the grip piece 2 , in turn a tensile carrier 3 can be provided, wherein this tensile carrier, in a particular embodiment, is embedded in the cover layer, that is, for example, the reinforcing layer is embodied free from a tensile carrier.
[0074] The use of thermoplastic elastomers for the handrails 1 means the advantage can also be achieved that they can be given a coloration with relatively simple means compared to natural rubber, i.e., a color that does not correspond to that of the base material. This can be achieved, for example, in that the base material itself is colored, i.e., is provided with a colorant, however, on the other hand it is also possible with coating systems already known to paint a layer onto the handrail, i.e., the grip piece 2 , in particular during the extrusion process, that is to carry out a so-called online coating.
[0075] FIG. 3 shows another embodiment of a handrail 1 according to the invention. This comprises in turn the grip piece 2 , the tensile carrier 3 in the grip piece 2 , and the sliding layer 4 on the underside of the grip piece 2 . The grip piece 2 in turn can be embodied in one layer or multiple layers, wherein the layers can also have different mechanical properties and can comprise different materials. In general the grip piece 2 is made of a polymer material, that is in particular of a thermoplastic elastomer, such as, e.g., TPU, TPV, TPO, of EPDM, natural rubber, CSM, CR, SBR, BR, NBR, BU, and mixtures or blends thereof.
[0076] The sliding layer 4 comprises a structure of warp threads 12 running at least approximately in the longitudinal direction of the handrail 1 and weft threads 13 running at least approximately orthogonally thereto. According to the invention, the weft threads have a higher rigidity than the weft threads, i.e., they are more rigid, that is they have a higher modulus of elasticity. The warp threads or weft threads can be produced from above-mentioned materials, wherein the fabric of the sliding layer 4 , i.e., the warp threads 12 and the weft threads 13 , can comprise the same material with different rigidities or materials differing from one another. For example, combinations of staple fibers of polyamide or polyester can be used for the warp threads 12 with fibers of polyester, multifilament yarns or aramide fibers for the weft threads 13 . This means that the handrail 1 can be given a higher lip rigidity while at the same time achieving flexibility in the longitudinal direction. The incorporation or arrangement of the sliding layer 4 into or on the grip piece 2 can be carried out here, as described for FIGS. 1 and 2 .
[0077] The weft threads 13 can thereby have an initial modulus of elasticity according to ASTM D 885 selected from a range with a lower limit of 6.0 GPa and an upper limit of 175 GPa. It is likewise possible for the weft threads 13 to have an initial modulus of elasticity selected from a range with a lower limit of 7.0 GPa and an upper limit of 165 GPa or of from a range with a lower limit of 8.0 GPa and an upper limit of 150 GPa. For example, the weft threads can have an initial modulus of elasticity according to ASTM D 885 of 80 GPa, 85 GPa, 90 GPa, 100 GPa, 115 GPa, 125 GPa or 150 GPa.
[0078] In return, the warp threads 12 can have an initial modulus of elasticity according to ASTM D 885 selected from a range with a lower limit of 4.5 GPa and an upper limit of 12 GPa.
[0079] In a particular embodiment, para-aramide fibers are used as weft threads 13 , for example, Twaron® or Kevlar® fibers.
[0080] The exemplary embodiments represent possible variations of the handrail 1 according to the invention, although the invention is not restricted to the these specific embodiments, but instead diverse combinations of the individual embodiments among one another are also possible and this variation possibility based on the directive for technical actions through the present invention lies within the ability of one skilled in the art working in this technical field. Therefore, all conceivable embodiments that are possible through combinations of individual details of the embodiments shown and described are also covered by the scope of protection.
[0081] To make it easier to understand the structure of the handrail 1 , the handrail 1 or its components have been shown in part not to scale and/or enlarged and/or reduced in size.
[0082] The object on which the independent inventive solutions are based can be taken from the specification.
[0083] Above all, the individual embodiments shown in FIGS. 1 , 2 ; 3 form the subject matter of independent inventive solutions. The objectives and solutions according to the invention in this regard can be taken from the detailed descriptions of these figures.
LIST OF REFERENCE NUMBERS
[0000]
1 Handrail
2 Grip piece
3 Tensile carrier
4 Sliding layer
5 Lip area
6 Recess
7 Edge
8 Area
9 Lip
10 Area
11 Surface
12 Warp threads
13 Weft threads
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The invention encompasses a handrail for escalators or moving walkways that includes a grip piece of a thermoplastic elastomer including soft segments and hard segments and optionally a sliding layer arranged on the underside of the grip piece relative to the mounting orientation of the handrail. A ratio of the proportions of the soft segments to the hard segments is selected from a range with a lower limit of 1:1 and an upper limit of 9:1, or, in a variation, from a range with a lower limit of 1.5:1 and an upper limit of 6:1, or, in another variation, from a range with a lower limit of 2.5:1 and an upper limit of 4:1.
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[0001] This application claims the benefit of Korean Patent Application No. 10-2006-0028932, filed on Mar. 30, 2006, which is hereby incorporated by reference for all purposes as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a drum washing machine capable of re-circulating wash water to clean laundry with a relatively less amount of water.
[0004] 2. Discussion of the Related Art
[0005] Generally, drum washing machines are home appliances that are used to clean laundry inside a drum by friction force between a rotary drum and laundry. Due to development of drum washing machines, laundry can be less damaged and less entangled and the laundry can be washed as if it were scrubbed by human hands.
[0006] A door is provided in a front part of a body in a conventional drum washing machine to load or unload laundry. When a user tries to put or take the laundry in or from a drum, the user should bend his/her waist or sit down, which is inconvenient to the user. The drum washing machine having a door provided in a front portion of its body will be referred to as a front loading-type drum washing machine.
[0007] Recently, top loading-type drum washing machines have been developed, in which an opening for loading/unloading laundry is formed in a circumference of a drum and a drum door is coupled to the opening. Thus, a user can open the door without bending his/her waist and can load or unload laundry inside the drum.
[0008] FIG. 1 illustrates a conventional top loading-type drum washing machine.
[0009] As shown in FIG. 1 , a conventional top loading-type drum washing machine 1 includes a body 3 , a tub 5 mounted within the body 3 to store wash water, and a drum 7 rotatable within the tub 5 to wash laundry therein.
[0010] There are provided in both sides of the drum a motor shaft 9 , a spider 2 , a motor 4 and a motor housing 6 . The motor shaft 9 transmits rotational force to the drum 7 . The spider 2 transmits the rotational force of the motor shaft 9 to the drum 7 . A plurality of elastic members 8 may be provided under the tub 5 to support the tub 5 .
[0011] According to the conventional top loading-type drum washing machine, the rotational force of the motor 7 is transmitted to the spider 2 via the motor shaft 9 and the drum 7 rotates during a washing and ringing cycle. The drum 7 rotates and the rotation of the drum 7 is damped by the elastic members 8 connected to the housing 6 in media of the bearing fastened to shafts provided in both sides of the drum 7 .
[0012] Since the conventional top loading-type drum washing machine may not have any secured space connected to the drum, a nozzle used in a conventional front loading-type drum washing machine may not be installed in the conventional top loading-type drum washing machine and it is impossible to re-circulate wash water.
[0013] That is, as shown in FIG. 1 , a drum operation mechanism is provided in a side of the drum and a mechanism for supporting rotation of the drum is provided in the other side of the drum. Hence, the overall drum is closed and it is impossible to install any means for connecting an inside of the drum to an outside of the drum.
SUMMARY OF THE INVENTION
[0014] Accordingly, the present invention is directed to a drum washing machine that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
[0015] An advantage of the present invention is to provide a top loading-type drum washing machine capable of re-circulating wash water to easily clean laundry with a relatively less amount of wash water.
[0016] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0017] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a drum washing machine includes a body; a drum rotatable in the body, wherein the drum comprises an opening formed in a predetermined portion of a circumference thereof and a hole formed in one side of the drum; a motor assembly mounted adjacent to the other side of the drum, wherein the other side of the drum is opposite to the hole; and an injection unit adjacent to the hole, wherein at least one of wash water or steam is injected into the drum through the hole.
[0018] In another aspect of the present invention, the drum washing machine further includes at least one bracket unit provided in the other side of the drum. The bracket is secured to the motor assembly and the body to support the drum.
[0019] The bracket unit includes at least one bracket secured to the motor assembly to support the drum; and at least one damper for damping vibration of the drum. One end of the damper fastened to the bracket and the other end of the damper fastened to the body.
[0020] The injection unit includes an injection nozzle adjacent to the hole to inject at least one of the wash water or steam into the drum through the hole.
[0021] In another aspect of the present invention, the drum washing machine may further include a nozzle window. At least one of the wash water or steam injected through the nozzle dampens laundry inside of the drum smoothly.
[0022] The nozzle window may include a lattice provided in some portion or an overall portion of the hole.
[0023] The nozzle window may include a lattice provided in some portion or overall portion of the hole, the lattice having an appearance substantially radial shape.
[0024] The hole may be formed in a substantially donut shape with respect to a center of one side of the drum.
[0025] A center of the hole may be spaced apart a predetermined distance from a center of one side of the drum.
[0026] The motor assembly includes a motor provided in one side of the drum to operate the drum; and a motor housing for mounting the motor. An end of the bracket is secured to the motor housing, and the other end of the bracket is bent and secured to an upper end of the damper.
[0027] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.
[0029] In the drawings:
[0030] FIG. 1 is a diagram schematically illustrating key parts of a conventional drum washing machine;
[0031] FIG. 2 is a diagram schematically illustrating key parts of a drum washing machine according to an embodiment of the present invention;
[0032] FIG. 3 is a sectional view schematically illustrating a damper shown in FIG. 2 ; and
[0033] FIGS. 4 to 7 are diagrams illustrating embodiments of the drum washing machine according to the present invention.
DETAILED DESCRIPTION
[0034] Reference will now be made in detail to the specific embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0035] FIG. 2 schematically illustrates key parts of a drum washing machine according to an embodiment the present invention and FIG. 3 schematically illustrates a damper shown in FIG. 2 . FIGS. 4 to 7 illustrate embodiments of the drum washing machine according to the present invention, respectively.
[0036] As shown in FIG. 2 , a drum washing machine 100 includes a body 10 , a drum 20 , a tub 22 , a motor assembly 30 and an injection unit 40 . The drum is rotatable within the body 10 . An opening 21 is formed in a predetermined portion of a circumference of the drum 20 and a hole 41 is formed in one side of the drum 20 . The tub 22 is installed to cover the drum 20 and it stores wash water therein. The motor assembly 30 is mounted adjacent to the other side of the drum 20 , which is opposite to the hole 41 , and it operates the drum 20 . The injection unit 40 is adjacent to the hole 41 to inject at least one of wash water or steam into the drum 20 through the hole 41 .
[0037] Also, the drum washing machine shown in FIG. 2 includes the motor assembly 30 as a drum operation mechanism, which is provided in the other side of the drum 20 , a bracket unit 36 and a damper 37 as a drum supporting mechanism, and the injection unit 40 for injecting at least one wash water or steam into the drum 20 through the hole 41 formed in the other side of the drum 20 , in which the hole is formed, to communicate with the inside of the drum 20 .
[0038] The opening 21 is in communication with the inside of the drum 20 so that a user may load laundry into the drum 20 through the opening 21 . Thus, it is preferred that an upper end of the tub 22 , that covers the drum 20 , and an upper end of the body 10 , that covers the tub 22 , are opened corresponding to the opening 21 .
[0039] The drum 20 includes a drum door 24 for closing the opening 21 . The drum door 24 may be sliding to close the opening 21 or one side of the drum door 24 may have a hinge structure to close the opening 21 .
[0040] The motor assembly 30 is provided in the other side of the drum 20 , which is opposite to the hole 41 , to operate the drum 20 so that the drum performs washing. Here, the motor assembly 30 includes a motor 33 and a motor housing 35 .
[0041] The motor 33 includes a motor operation shaft 31 connected to the drum 20 and thus the motor 33 transmits a driving force to the drum 20 via the motor operation shaft 31 . The motor 33 is secured to the other side of the drum 20 by the motor housing 35 .
[0042] As mentioned above, the hole 41 is provided in one side of the drum 20 in communication of the inside of the drum 20 . Together with the hole 41 , the injection unit 40 is also provided in the one side of the drum 20 , adjacent to the opening 21 . Thus, at least one of wash water or steam is injected into the drum 20 through the hole 41 by the injection unit 40 .
[0043] As shown in FIG. 2 , the injection unit 40 includes an injection nozzle 45 adjacent to the hole 41 . Also, the injection unit 40 may include an injection spray mechanism that sprays wash water or steam into the drum 20 through the hole 41 . That is, the injection unit 40 may includes all kinds of structures that can supply wash water or steam into the drum 20 in a predetermined pressure and speed, for example injecting or spraying, to make wash water or steam reach the laundry adhering to inner surfaces of the drum 20 . If the injection unit 40 injects steam, a steam generation part may be connected to the injection unit 40 , though not shown in the drawings. The drum washing machine of the embodiment of FIG. 2 further includes a nozzle window 43 provided at a hole provided at one side of the drum. The nozzle window 43 orients wash water or steam injected through an injection unit 40 to dampen the laundry inside of the drum smoothly.
[0044] The drum washing machine according to the present invention is a top loading-type drum washing machine characterized in that the drum is supported in one side and the injection unit is provided in the other side of the drum to inject at least one of wash water or steam into the drum.
[0045] When the drum is supported in one side, vibration may be generated severely and the supporting force may be insufficient during the drum rotation. As a result, the drum and the motor assembly provided in one side of the drum might collide against each other and become damaged.
[0046] To damp the vibration and supply the sufficient supporting force, the drum washing machine according to the present invention may further include a bracket unit.
[0047] As shown in FIG. 2 , the bracket unit includes at least one bracket 36 and at least one damper 37 . The bracket 36 is fastened to the motor assembly 30 to support the drum 20 . One end of the damper 37 is fastened to the bracket 36 and the other end of the damper 37 is fastened to the body 10 to damp the vibration of the drum 20 transmitted through the bracket 36 .
[0048] One end of the bracket 36 is secured to a predetermined portion of the motor housing 35 and the other end of the bracket 36 is secured to an upper end of the damper 37 . It is preferred that the bracket 36 is provided in plural, considering safety of drum operation.
[0049] As shown in FIG. 2 , one end of the bracket 36 is secured to the motor housing 35 and thus the vibration of the drum 20 is transmitted through the bracket 36 during the drum rotation. The other end of the bracket 36 is movable due to the vibration of the drum 20 .
[0050] Since the damper fastened to the other end of the bracket 36 damps the motion of the other end of the bracket 36 , the vibration generated from the drum rotation may be effectively damped.
[0051] Here, the bracket 36 is bent at a predetermined portion and a bending part (B) is formed at the bracket 36 to damp some of the vibration of the drum before the vibration is transmitted to the damper 37 .
[0052] The damper 37 may be fixed under the rotation center of the drum 20 within the body 10 . The rotation center of the drum 20 is a rotation center in connection with the weight of components related to the drum rotation.
[0053] As shown in FIG. 3 , the damper 37 of the embodiment of FIG. 2 may include a damper housing 39 , an elastic member 32 and a piston member 34 . The damper housing 39 is mounted in the body 10 . The elastic member 32 is provided in a longitudinal direction of the damper housing 39 . The piston member 34 is movable upward/downward along the longitudinal direction of the damper housing 39 .
[0054] The other end of the bracket 36 is fastened to an upper end of the piston member 34 and the elastic member 32 is provided at a lower end of the piston member 34 , to support the piston member 34 .
[0055] Fluid having high coefficient of viscosity may be provided within the damper housing 39 and the portion through which the fluid is filled is tightly sealed, such that the damping efficiency of the damper 37 may be enhanced.
[0056] As shown in FIG. 2 , balancing members 23 are provided at four side ends of the drum 20 , respectively. Also, a pump 25 is provided on an inner bottom surface of the body 10 to pump wash water so that the wash water is injected into the drum by the injection unit 40 .
[0057] Embodiments shown in FIGS. 4 to 7 will be now described.
[0058] As shown in FIGS. 4 to 7 , a drum washing machine according to the present invention further includes a nozzle window 43 , 63 and 73 provided at a hole provided at one side of a drum. The nozzle window 43 , 63 and 73 orients wash water or steam injected through an injection unit to dampen the laundry inside of the drum smoothly.
[0059] According to a first embodiment, as shown in FIG. 4 , the nozzle window 43 may be provided at some portion or an overall portion of the hole 41 in a lattice shape. In other words, the nozzle window 43 is formed by a lattice 44 .
[0060] The injection unit 40 is installed adjacent to the nozzle window 43 . The hole 41 is provided in a center of one side of the drum 20 and the nozzle window 43 is provided at an overall portion of the hole 41 or provided at a predetermined portion of a center of the hole 41 .
[0061] Thus, wash water or steam may be distributed over the inside of the drum 20 by the lattice 44 of the nozzle window 43 , or a motion path of the wash water or steam injected in a predetermined pressure and speed is changed to uniformly supply the wash water or steam to the laundry. Especially, when a soaking cycle is performed, the laundry may be adhering to an inner surface of the drum during the drum rotation. At this time, the lattice 44 of the nozzle window 43 allows the wash water or steam to be supplied to and to dampen the laundry adhering to the inner surface of the drum 20 uniformly.
[0062] FIG. 5 illustrates a nozzle window and a lattice according a second embodiment.
[0063] As shown in FIG. 5 , a hole 41 provided at one side of the drum 20 and a center of the hole 41 is spaced apart a predetermined distance from a center of one side of the drum 20 .
[0064] That is, the hole 41 is eccentric from the center of one side of the drum 20 and it rotates eccentrically when the drum 20 rotates. Accordingly, the nozzle window 43 eccentrically rotates with respect to the center of the drum 20 such that the wash water or steam injected by the injection unit may easily reach the laundry adhering to the inner surface of the drum 20 through the nozzle window 43 .
[0065] FIG. 6 illustrates a nozzle window 63 and a lattice 64 according to a third embodiment.
[0066] As shown in FIG. 6 , the nozzle window 63 is radial from a center of one side of the drum 20 . That is, a lattice 64 having a radial shape is provided at the hole 41 and the radial shaped nozzle window 63 is formed by the radial shaped lattice 64 . The nozzle window 63 is provided in a radial shape and the wash water or steam is injected in all direction, that is, a radial direction.
[0067] FIG. 7 illustrates a nozzle window 73 and a lattice 74 according to a fourth embodiment.
[0068] As shown in FIG. 7 , the nozzle window 73 is formed in a donut shape with respect to the center of one side of the drum 20 . For the donut shaped nozzle window 73 , a hole 71 is also formed in a donut shape with respect to the center of one side of the drum 20 . The nozzle window 73 is formed at one side of the drum 20 in a donut shape, such that wash water may be injected to an upper and lower part of the laundry uniformly.
[0069] As mentioned above, in the drum washing machine according to the present invention, which is a top loading-type, the predetermined components to support the drum may be provided in one side of the drum and not provided in the other opposite side of the drum. Thus, inner space of the drum may be relatively wide and washing capacity may be enhanced, compared to the same overall size of a conventional top loading-type drum washing machine as well as a conventional front loading-type drum washing machine.
[0070] Moreover, while there are provided in one side of the drum the components for supporting the drum, there are provided in the other side of the drum the injection unit for injecting at least one of wash water or steam. At least one of wash water or steam is injected into the drum through the hole and thus washing efficiency is high even with a relatively small amount of wash water.
[0071] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
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The present invention relates to a drum washing machine capable of re-circulating wash water to clean laundry with a relatively less amount of water. The drum washing machine includes a body, a drum rotatable in the body, wherein the drum comprises an opening formed in a predetermined portion of a circumference thereof and a hole formed in one side of the drum, a motor assembly mounted adjacent to the other side of the drum, wherein the other side of the drum is opposite to the hole, and an injection unit adjacent to the hole, wherein at least one of wash water or steam is injected into the drum through the hole.
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PRIORITY CLAIM
[0001] This U.S. application for utility patent is a divisional of U.S. patent application Ser. No. 10/944,635, filed Sep. 17, 2004.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to compositions of cyanoacrylate monomer and polymer adhesive compositions, a process for sterilizing them for application in the medical and veterinary fields, and a method of assaying the sterilization of cyanoacrylate compositions.
[0004] 2. Background
[0005] It is known to use 2-cyanoacrylate esters as adhesives for bonding tissue in medical or surgical procedures performed upon the human or animal body. 2-cyanoacrylate esters polymerize rapidly, and often instantaneously, upon contact with tissue or body fluid. In these applications, the adhesive composition can be used to close wounds, as well as for covering and protecting surface injuries such as lacerations, abrasions, burns, sores and other open surface wounds. To be used in medical and veterinary fields, 2-cyanoacrylates must be sterilized. This is generally done in sealed containers to provide sterility, and from a practical perspective, to protect the compositions from moisture and premature polymerization. Previous sterilization methods involved either the use of ionizing radiation, including e-beam and gamma ray irradiation, dry heat at elevated temperatures (160° C.), or chemical sterilization such as with ethylene oxide.
[0006] When an adhesive composition is applied to a surface to be closed or protected, it is usually in its monomeric form, and the resultant polymerization produces the desired adhesive bond. However, at ordinary temperatures, the monomeric form of the adhesive has a low viscosity which results in the adhesive spreading into undesired areas. Therefore, it is desirable to increase the viscosity of the composition to prevent this unwanted flow. In order to achieve an increased viscosity, thickening agents can be added to the monomeric composition.
[0007] The previous methods of sterilization are undesirable in that the high temperatures required for the previous dry heat sterilization processes or irradiation could cause premature polymerization of the monomers. In addition, many polymers that could be used as thickeners underwent degradation resulting in loss of viscosity when exposed to typical dry heat conditions of 160° C. This significantly limits the formulators ability to formulate adhesive compositions which have the desirable stability and flow characteristics, and which can be sterilized.
BRIEF SUMMARY OF THE INVENTION
[0008] The present invention is directed to a method of sterilizing 2-cyanoacrylate compositions, including heating the composition in a device at a temperature of from about 70° C. to about 140° C. for an effective amount of time. In another aspect, the invention includes sterilized 2-cyanoacrylate ester compositions for use in medicine or surgery, the compositions being disposed in sealed aluminum containers and being sterilized at a temperature of between about 70° C. and about 140° C. The compositions can be disposed in sealed aluminum, tin, stainless steel tubes or pouches or glass containers. Preferably, the 2-cyanoacrylate compositions are adjusted to an initial viscosity of 400 to 600 centipoises by the addition of polycyanoacrylate thickeners, and are sterilized in a preferred method by heating them at a temperature of no greater than about 110° C. for no more than about 120 minutes. Articles of manufacture are vials or squeezable tubes made of compatible glass, aluminum, or plastic.
[0009] In yet another aspect, the invention is directed to a method for assaying the sterilization of cyanoacrylate compositions.
DETAILED DESCRIPTION OF THE INVENTION
[0010] As embodied and described herein, the present invention provides a novel method of sterilizing 2-cyanoacrylate ester compositions using a combination of chemical and heating means, and the resulting novel compositions. The combination of monomeric 2-cyanoacrylate, heat and time have a lethal effect on microbials, rendering sterilized compositions when the appropriate sterilization condition is achieved and when the method is applied to 2-cyanoacrylates in sealed containers.
[0011] As used herein, the following terms have the following meanings:
[0012] The term “cyanoacrylate adhesive composition” or “cyanoacrylate adhesive compositions” refers to polymerizable formulations comprising polymerizable cyanoacrylate ester monomers. The term aldose is intended to refer to both common disaccharides and monosaccharides.
[0013] In the method of the invention, 2-cyanoacrylate adhesive compositions are sterilized through an unexpected and heretofore unknown combination of heat and time, sterilizing at temperatures significantly lower than previously thought to be effective. Previous dry heat sterilization methods have required temperatures of at least 160° C. to 180° C. Heating times at these temperatures were from 2 hours at 160° C. to 30 minutes at 180° C. Under the present invention, the 2-cyanoacrylate adhesive compositions can be sterilized at temperatures from about 70° C. to about 140° C. As would be expected, the time required to effect sterilization will vary depending on the temperature selected to accomplish the sterilization. At 140° C., sterilization requires approximately 30 minutes. At 70° C., sterilization requires about 600 minutes. Required heating times for intermediate temperatures are reported in Tables 2 and 3. Ultimately sterilization times for any composition can be readily determined by one skilled in the art by standard test methods without undue experimentation.
[0014] Typical sterilization times are listed in Table 1.
[0000]
TABLE #1
sterilization heating times
70° C.
600 minutes
80° C.
480 minutes
90° C.
300 minutes
100° C.
120 minutes
110° C.
90 minutes
120° C.
60 minutes
130° C.
60 minutes
140° C.
30 minutes
[0015] According to the assay method of the invention, sterilization of cyanoacrylate compositions can be assayed for the effectiveness of a given temperature and sterilization time. Samples containing formulated n-butyl cyanoacrylate and 2-octyl cyanoacrylate in sealed borosilicate glass and aluminum tubes were inoculated with Bacillus subtilis lyophilized spores at a concentration of 1×10 +6 per ml of formulation. In other embodiments, spores can be introduced into the cyanocrylate adhesive compositions prior to sterilization using commercially available biological indicators or spore test strips. Among the commercially available biological indicators which may be used are: bacterial spores on a stainless steel disc, bacterial spores on a steel wire, bacterial spores on steel coupons, bacterial spores on borosilicate paper and bacterial spores on woven cotton threads. Among the species of spores which may be chosen for use in the commercially available biological indicators are Bacillus subtilis and Geobacillus stearothermophilus . Commercially available biological indicators may be obtained from any commercial supplier, such as Raven Labs. Some inoculated glass vials and tubes samples were kept at room temperature without sterilization as positive controls, while the rest of the samples were sterilized at temperatures ranging from 70 to 140° C. with different time exposures. Samples were sent to a microbiology laboratory for determination of the presence or absence of growth after the sterilization procedure was completed to assay the effectiveness of the process conditions.
[0016] In accordance with the present invention it is preferred to utilize microorganisms which may be killed by the sterilization process but which show significant resistance to this process. The term microorganism refers to bacteria, fungi, yeast, protozoa algae, viruses and protozoa. Bacterial spores are very resistant to heat and chemicals; more so than vegetative bacterial cells, therefore the spores are often used to monitor sterilization procedures. A preferred organism for monitoring dry heat sterilization is Bacillus subtilis.
[0017] The spores represent a resting stage in the life cycle of the Bacillus genus. The resting spore contains a large number of active enzymes which allow the transformation from dormant cell to vegetative cell. The germination process, or the return to the vegetative state, has been described as a time-ordered sequence involving activation, triggering, initiation and outgrowth. Activation is reversible and involves an increase in the rate and extent of germination. Triggering is irreversible and is the result of spore contact with the germinant. Initiation involves the loss of heat resistance, release of dipicolinic acid and calcium, loss of refractility and absorbance. Outgrowth results in formation of the vegetative cell.
[0018] In accordance with the present invention a cyanoacrylate composition test sample comprising at least one sterility test strip, or lyophilized spores is utilized. While reference is made to “spores” as a test microorganism it should be understood that microorganisms other than spore formers may be used in conjunction with the present invention. The spore strips utilized with the present invention are preferably constructed of materials which are inert to the microorganisms and inert to cyanoacrylate monomer. A variety of commercial spore strips is readily available and can be utilized with the present invention. The spore strips can contain more than one type of microorganism.
[0019] To assay the sterilized samples and controls, the compositions including the biological indicators are transferred into containers filled with an aqueous aldose solution, shaken, and transferred into a quantity of nutrient medium in an aseptic container. Transferring the samples to an aldose solution serves to emulsify the cyanoacrylate monomer without causing it to polymerize as it would upon exposure to water alone. Aldoses which act to emulsify the cyanoacrylate include without limitation, dextrose, lactose, arabinose, mannose, galactose, rhamnose, fructose, sucrose and glucose. In one embodiment of the invention, the aldose is dextrose. The concentration of the aldose solution may be from about 2% to about 50% on a weight/weight basis. A preferred range for the concentration of the aldose solution is from about 3% to about 15%. A more preferred aldose concentration is from about 5% to about 10% weight/weight. The nutrient medium supports the germination of spores and growth of any viable microorganisms. The nutrient medium contains a protein substrate for the proteases liberated during spore germination and during subsequent microbial growth. The nutrient medium preferably comprises an aqueous solution or suspension of nutrient components (including the protein substrate) needed in order to promote the growth of viable microorganisms that may exist after the sterilization process. One example of a suitable culture medium is a protein-containing microbiological broth such as tryptic soy broth (TSB) and/or TSB with specific protein additives, such as, for example, casein. Formulations for culture media are well-known to those in the art.
[0020] The mixture of microorganisms, cyanoacrylate, aldose and nutrient medium are then sealed within a containing means. The samples are then incubated for a predetermined period of time at from about 28° C. to about 37° C. Any microorganisms not killed during the sterilization process begin to germinate and grow during the incubation period. In a preferred embodiment the microorganisms are incubated for at least about seven days. Thereafter the sample is examined to detect the presence of growth by different methods, such as visual examination of the samples followed by microscope Gram stain examination, addition of an enzymatic indicator such as tetrazolium salts followed by UV spectrophotometric analysis, or direct UV spectrophotometric analysis of incubated samples. In one embodiment, after visual examination a gram stain smear is prepared to look for gram positive rods which would confirm growth. In another embodiment, growth can be determined by the addition of enzymatic biological indicator such as tetrazolium salts, wherein bacterial activity is determined by development of color which may be measured quantitatively with an ultraviolet spectrophotometer at 257 nm. In yet another embodiment, a sample without enzymatic indicator is analyzed under a spectrophotometer at a wavelength of 480 nm to determine growth.
[0021] The method of the invention can be applied in principle to any 2-cyanoacrylate ester monomer. The 2-cyanoacrylate is preferably an aliphatic cyanoacrylate ester and preferably an alkyl, cycloalkyl, alkenyl, alkoxyalkyl, fluoroalkyl, fluorocyclic alkyl or fluoroalkoxy 2-cyanoacrylate ester. The alkyl group may contain from 2 to 12 carbon atoms, and is preferably a C 2 to C 8 alkyl ester, and is most preferably a C 4 to C 8 alkyl ester. Suitable 2-cyanoacrylate esters include without limitation, the ethyl, n-propyl, iso-propyl, n-butyl, pentyl, hexyl, cyclohexyl, heptyl, n-octyl, 2-ethylhexyl, 2-methoxyethyl and 2-ethoxyethyl esters. Any of these 2-cyanoacrylate monomers may be used alone, or they may be used in mixtures.
[0022] The 2-cyanoacrylate monomers of the invention can be prepared by any of the methods known in the art. U.S. Pat. Nos. 2,721,858, 3,254,111 and 4,364,876, each of which is hereby incorporated in its entirety by reference, disclose methods for preparing 2-cyanoacrylates. For example, cyanoacrylates for the instant invention were prepared by reacting cyanoacetate with formaldehyde in the presence of heat and a basic condensation catalyst to give a low molecular weight polymer. A depolymerization step followed under heat and vacuum in the presence of acidic and anionic inhibitors, yielding a crude monomer that could be distilled under vacuum and in the presence of radical and acidic inhibitors. The distilled 2-cyanoacrylate monomers are then formulated with radical and acidic inhibitors depending upon their application and to provide the necessary stability.
[0023] The 2-cyanoacrylate compositions of the invention may in some embodiments contain a thickening agent to increase the viscosity of the composition. This thickening agent may be a polymer. The thickening agent may be selected from the group consisting of without limitation, poly alkyl-2-cyanoacrylates, poly cycloalkyl-2-cyanoacrylates, poly fluoroalkyl-2-cyanoacrylates, poly fluorocycloalkyl-2-cyanoacrylates, poly alkoxyalkyl-2-cyanoacrylates, poly alkoxycycloalkyl-2-cyanoacrylates, poly fluoroalkoxyalkyl-2-cyanoacrylates, polyalkoxycyclofluoroalkyl-2-cyanoacrylates, poly vinylacetate, poly lactic acid and poly glycolic acid. In order to obtain optimum solubility of the polymer in the monomer, the polymer is often chosen to be a polymer of the monomer or one of the monomers which comprise the 2-cyanoacrylate composition. Preferably, the polymer is soluble in the monomer composition at ambient temperature. Preferred polymers include polymers of octyl 2-cyanoacrylate, vinyl acetate lactic acid, or glycolic acid. The preferred weight average molecular weight of the polymers is from about 300,000 to about 2,000,000. More preferably, the polymer molecular weight is from about 500,000 to about 1,600,000.
[0024] Cyanoacrylate polymers of the invention can be prepared by slow addition of the monomer to a mixer containing 0.1% bicarbonate deionized water. Water is then decanted away, and the polymer is rinsed several times with deionized water and decanted again. Following steps include neutralizing the polymer with 0.1 N HCl, rinsing with deionized water, drying on a vacuum heated oven at temperature of less than 80° C. and grinding the polymer to fine particles.
[0025] The amount of thickening agent that is added to the monomer composition is dependent upon the molecular weight of the polymer and the desired viscosity for the adhesive composition. The thickening agent typically is added at from about 1% to about 25% by weight of the composition. Preferably it is added at from about 1% to about 10%. More preferably it is added at from about 1% to about 5%. A typical viscosity of the composition is from about 25 to about 3000 centipoise, as measured by a Brookfield viscometer at 25° C. Preferably, the viscosity is between from about 50 to 600 centipoise at 25° C. The specific amount of a given thickening agent to be added can be determined by one of ordinary skill in the art without undue experimentation.
[0026] The 2-cyanoacrylate compositions may contain one or more acidic inhibitors in the range from 1 to 1,000 ppm. Such acidic inhibitors include without limitation: sulfur dioxide, nitrogen oxide, boron oxide, phosphoric acid, ortho, meta, or para-phosphoric acid, acetic acid, benzoic acid, cyanoacetic acid, tri-fluoroacetic acid, tribromoacetic acid, trichloroacetic acid, boron trifluoride, hydrogen fluoride, perchloric acid, hydrochloric acid, hydrobromic acid, sulfonic acid, fluorosulfonic acid, chlorosulfonic acid, sulfuric acid, and toluenesulfonic acid.
[0027] The 2-cyanoacrylate compositions may contain one or more free radical polymerization inhibitors in the range from 0 to 10,000 ppm. Examples such radical inhibitors include, without limitation, catechol, hydroquinone, hydroquinone monomethyl ether and hindered phenols such as butylated hydroxyanisol, butylated hydroxytoluene (2,6-di-tert-butyl butylphenol and 4methoxyphenol), 4-ethoxyphenol, 3 methoxyphenol, 2-tert-butyl-4methoxyphenol, and 2,2 methylene-bis-(4-methyl-6-tert-butylphenol).
[0028] The 2-cyanoacrylate compositions may contain single or mixtures of plasticizers such as tributyl acetyl citrate, dimethyl sebacate, diethyl sebacate, try-ethyl phosphate, tri-(2ethylhexyl)phosphate, tri-cresyl phosphate, glyceryl triacetate, glyceryl tributyrate, dioctyl adipate, isopropyl myristate, butyl stearate, trioctyl trimellitate, and dioctyl glutarate. The plasticizers may be added to the compositions in proportions of less than 50% w/w of the formulation.
[0029] The 2-cyanoacrylate compositions may contain small amounts of dyes like the derivatives of anthracene and other complex structures. Some of these dyes include, without limitation, 1-hydroxy-4-[4-methylphenylamino]-9,10 anthracenedione (D&C violet No.2), disodium salt of 6-hydroxy-5-[(4-sulfophenyl)axo]-2-naphthalene-sulfonic acid (FD&C Yellow No.6,), 9-(o-carboxyphenyl)-6-hydroxy-2,4,5,7-tetraiodo-3H-xanthen-3-one disodium salt monohydrate (FD&C Red No.3), 2-(1,3dihydro-3-oxo-5-sulfo-2 -indole-2-ylidine)-2,3-dihydro-3-oxo-IH-indole-5-sulfonic acid disodium salt (FD&C Blue No.2), and [phthalocyaninato (2)] copper added in proportions of less than 50,000 ppm.
[0030] The sterilized cyanoacrylate adhesive compositions of the invention may be packaged in a container made of any suitable material. Suitable materials must be heat stable and resistant up to the sterilization temperature, must provide an adequate barrier to atmospheric moisture and be compatible with the cyanoacrylate monomer or monomers. Materials meeting these requirements include metals and borosilicate type I glass. Suitable metals can include without limitation aluminum, tin, and stainless steel. Metals can have different forms like pouches and tubes. Glass can be used as vials, breakable tubes or any other shape, and contained inside tubes made out of the same material, or combinations or materials including plastics. Particularly preferred materials are aluminum and type I glass. Preferred aluminum tubes comprise a nozzle which is hermetically sealed by a pierceable membrane of aluminum and are filled at their end remote from the nozzle prior to closure of the open end by tight crimping. The glass vials used in this invention, are made out of borosilicate type I glass and sealed with a threaded phenolic cap with a silicone/Teflon septum or sealed with an aluminum crimp cap and a silicone/Teflon septum. In the result, therefore, preferred embodiments of the invention reside in a substantially hermetically sealed aluminum container, e.g. an aluminum tube, containing a sterile 2-cyanoacrylate composition or type I glass vials hermetically sealed with a phenolic threaded cap and a silicone/Teflon septum.
EXAMPLES
Example 1
Sample Testing: (Sterility Test Method for All Samples)
[0031] The method was tested by first performing the USP bacteriostasis and fungi stasis test on glass vials and aluminum tubes. The sterility test was performed by obtaining spores of Bacillus subtilis var. niger suspended in irrigation water at a concentration of 2.3×10 +8 /ml. Aliquots of 0.48 ml of these spores were placed in glass serum bottles, lyophilized and then reconstituted with 50 ml of n-butyl or 2-octylcyanoacrylate compositions to obtain a volume of 50 ml of inoculated spore solution with a concentration of 2×10 +6 /ml. These cyanoacrylate spore solutions were used to fill the tubes and vials for the sterilization trials at different temperatures and time and for the non-sterilized (standard biological indicators) control vials and tubes. Each tube and vial was filled with a volume of 0.5 to 0.6 ml of a cyanoacrylate composition that rendered a spore concentration of 2×10 +6 /ml. Non-sterilized biological indicators and sterilized spores inoculated samples at different temperatures and time were transferred to a 5% dextrose USP solution, shaken and transferred to soy casein digested broth (SCDB) and incubated at 35-37° C. for at least seven days. A vial of lyophilized spores with no cyanoacrylate was tested for population verification. The vial was transferred to sterile purified water and vortexed for 10 minutes. Serial dilutions of 10 +4 , 10 +5 , and 10 +6 were plated in duplicate using soy casein digested broth (SCDB) and incubated for 48 hours at 35-37° C. The 10 +6 dilution yielded duplicate plates in the countable range. The final calculations showed there were 6.1×10 +6 CFU/ml, or 3.1×10 +7 CFU/vial.
Polymer Preparation: (Polymer Method for Samples Containing Polymer)
[0032] 2-OCA polymer was made by adding drop by drop 30 grams of 2-OCA monomer to a blender containing 1000 ml of 0.1% sodium bicarbonate deionized water while swirling. Bicarbonate water with the polymer was vacuum filtered on a Kitasato with a Fisherbrand #Q5 quantitative filter paper, rinsed five times with 500 ml aliquots of deionized water and decanted. The polymer was neutralized with 500 ml of 0.1 N hydrochloric acid. The neutralized polymer was rinsed with three aliquots of 500 ml, decanted, dried in a vacuum oven at 80° C., and after drying was finely ground with a mixer.
Sample Composition Preparation:
[0033] The sample of 2-OCA containing polymer was made by mixing 2-octyl cyanoacrylate (stabilized with 100 ppm of SO 2 , 1000 ppm of butylated hydroxyanisole) with 3.5% of 2-OCA polymer. The polymer was dissolved in the formulated 2-OCA by heating and mixing in a round glass flask equipped with a paddle shaft and mixer at a temperature no higher than 80° C. and obtaining a viscosity of 567 cp (measured with a Brookfield DV-III at 25° C.). Then, the composition was inoculated with lyophilized Bacillus subtilis spores to produce a minimum concentration of 1×10 +6 which were filled in aluminum tubes and glass type I glass threaded vials. Tubes were sealed by crimping with a Kentex automatic tubes filler and sealer. The glass vials were filled with an Eppendorf automatic pipette and sealed with threaded phenol caps and silicone/Teflon septa. Some inoculated glass and tube samples were not sterilized and were used as positive standard biological indicators to indicate livable spores. The rest of the inoculated and sealed tubes and vials were exposed to the experimental temperatures and time stipulated in the sterilization testing protocol conditions.
[0034] Tables #2-3 shows example results.
[0000] TABLE #2 2-OCA sterilization example packed in glass vials with pre-sterilization viscosity of 567 cp Sterilization Type of Incubation Number Number of Sterilization time Media temperature samples days of Number of Viscosity @ ° C. minutes 400 ml ° C. tested incubated positives 25° C. sterile 90 240 SCDB 30-35 3 7 1 566 100 120 SCDB 30-35 3 7 0 569 100 180 SCDB 30-35 3 7 0 562 110 60 SCDB 30-35 3 7 0 526 110 120 SCDB 30-35 3 7 0 452 120 60 SCDB 30-35 3 7 0 418 120 90 SCDB 30-35 3 7 0 N/A 130 60 SCDB 30-35 3 7 0 343 130 120 SCDB 30-35 3 7 0 N/A 140 30 SCDB 30-35 3 7 0 110 140 45 SCDB 30-35 3 7 0 N/A
Table #2 above shows minimum sterilization temperatures, incubation temperature, incubation time and the results obtained for samples of Bacillus subtilis spores inoculated 2-OCA containing 3.5% 2-OCA polymer (567 cp), 100 ppm SO 2 and 1000 ppm BHA.
[0000] TABLE #3 2-OCA sterilization example packed in aluminum tubes with pre-sterilization viscosity of 567 cp Sterilization Type of Incubation Number Number of Sterilization time Media temperature samples days of Number of Viscosity @ ° C. minutes 400 ml ° C. tested incubated positives 25° C. sterile 90 240 SCDB 30-35 3 7 2 565 100 120 SCDB 30-35 3 7 0 566 100 180 SCDB 30-35 3 7 0 570 110 60 SCDB 30-35 3 7 0 526 110 120 SCDB 30-35 3 7 0 435 120 60 SCDB 30-35 3 7 0 405 120 90 SCDB 30-35 3 7 0 N/A 130 60 SCDB 30-35 3 7 0 351 130 120 SCDB 30-35 3 7 0 N/A 140 30 SCDB 30-35 3 7 0 102 140 45 SCDB 30-35 3 7 0 N/A
Table #3 above shows minimum sterilization temperatures, incubation temperature, incubation time and the results obtained for samples of Bacillus subtilis spores inoculated 2-OCA containing 3.5% 2-OCA polymer (567 cp), 100 ppm SO 2 and 1000 ppm BHA. Note the sharp drop in the viscosities of the compositions tested and shown in Tables 2 and 3 as temperature passes 110° C. The average viscosity drop from the base viscosity (567 cp) in the last column in each table going from row 4 to row 5 is 14.45%.
Example II
Sample Composition Preparation:
Sample IIA:
[0035] A sample of n-butyl cyanoacrylate (n-BCA) with a viscosity of 2.8 cp (measured with a Brookfield DV-II at 25° C.) containing 100 ppm of SO 2 and 1000 ppm of butylated hydroxyanisole (BHA) was prepared for this example. Then, the composition was inoculated with biological indicator standards such as borosilicate spore discs, cotton threads and spore wires with a spore concentration of 1×10 +6 Geobacillus stearothermophilus . The spore inoculated composition was filled in type I glass threaded vials with an Eppendorf automatic pipette and sealed with threaded phenol caps and silicone/Teflon septa. Some inoculated glass vials were not sterilized and were used as positive standard biological indicators to indicate livable spores. The rest of the inoculated sealed vials were exposed to the experimental temperatures and times stipulated in the sterilization testing protocol conditions.
[0000] Table #4 shows example results.
[0000] TABLE #4 n-BCA monomer sterilization example in glass vials with pre-sterilization viscosity of 2.8 cp Sterilization Type of Incubation Number Number of Sterilization time Media temperature samples days of Number of Viscosity @ 100° C. minutes 400 ml ° C. tested incubated positives 25° C. sterile Borosilicate 240 SCDB 55-60 3 7 0 2.9 disc Cotton 240 SCDB 55-60 3 7 0 2.8 threads SS wires 240 SCDB 55-60 3 7 0 2.8 Positive NO SCDB 55-60 3 2 3 2.8 control borosilicate disc Positive NO SCDB 55-60 3 2 3 2.9 Control cotton threads SS wires NO SCDB 55-60 3 2 3 2.8
Table #4 above shows sterilization temperatures, incubation temperature, incubation time and the results obtained for samples of Geobacillus stearothermophilus spores inoculated n-BCA containing, 100 ppm SO 2 and 1000 ppm BHA.
Sample IIB:
[0036] A sample of n-butyl cyanoacrylate (n-BCA) with a viscosity of 2.8 cp (measured with a Brookfield DV-II at 25° C.) containing 100 ppm of SO 2 and 1000 ppm of butylated hydroxyanisole (BHA) was prepared for this example. Then, the composition was inoculated with biological indicator standards cotton threads with a spore concentration of 1×10 +6 Bacillus subtilis . The spore inoculated composition was filled in type I glass threaded vials with an Eppendorf automatic pipette and sealed with threaded phenol caps and silicone/Teflon septa. Some inoculated glass vials were not sterilized and were used as positive standard biological indicators to indicate livable spores. The rest of the inoculated sealed vials were exposed to the experimental temperatures and times stipulated in the sterilization testing protocol conditions.
[0000] Tables #5 shows example results.
[0000] TABLE #5 n-BCA monomer sterilization example in glass vials with pre-sterilization viscosity of 2.8 cp Sterilization Type of Incubation Number Number of Sterilization time Media temperature samples days of Number of Viscosity @ 100° C. minutes 400 ml ° C. tested incubated positives 25° C. sterile Cotton 240 SCDB 55-60 3 7 1 2.8 threads Positive NO SCDB 55-60 3 2 3 2.8 Control cotton threads
Table #5 above shows sterilization temperatures, incubation temperature, incubation time and the results obtained for samples of Bacillus subtilis spores inoculated n-BCA containing 100 ppm SO 2 and 1000 ppm BHA.
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Adhesive 2-cyanoacrylate compositions are adjusted to a preferred initial viscosity of 400 to 600 centipoises by the addition of polycyanoacrylate thickeners, and are sterilized in a preferred method by heating them at a temperature of no greater than about 110° C. for no more than about 120 minutes. Articles of manufacture are vials or squeezable tubes made of compatible glass, aluminum, or plastic.
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FIELD OF THE INVENTION
The invention relates to a fabric teaseling machine of the type that comprises a rotor to which the fabric to be processed is fed and from which said fabric is drawn; this rotor comprises a plurality of revolving cylinders provided with teaseling clothing and arranged on the periphery of the rotor with their axes parallel to that of said rotor and being rotated simultaneously with each other and independently of the revolution of the rotor by which the fabric is caused to advance. The fabric is deflected by the various teaseling cylinders, each of which deflects the fabric by a small amount toward the adjacent cylinder along a rectilinear span; the geometry of the assembly of rotor and teaseling cylinders is such that the fabric is deflected through a fixed angle by each cylinder, so that the amount of teaseling effected by the surface clothing of each cylinder is determined partly and uncertainly by the adjustment of the tension of the fabric that is sent around the cylinders of the rotor.
The invention relates to an improved teaseling machine with which it is possible to vary the deflection of the fabric from one teaseling cylinder to the next and so to vary the action of the teaseling clothing on the fabric, as a function of adjustment that may be carried out on the rotor of said machine. This makes it possible both to adjust the teaseling or brushing action and also to utilize differing teaseling clothings, including clothings with relatively flexible brushes or abrasive coverings. These and other objects and advantages will become evident on reading the following text.
BACKGROUND OF THE INVENTION.
A teaseling machine of the abovementioned type has already been proposed: it has groups of cylinders on individual mountings that can be moved angularly to put teaseling cylinders from each group, selected from a set of three,.teaseling cylinders, in an active position; in particular it provides for the activation of only one of the teaseling cylinders of a set of three or two teaseling cylinders of a set of three on each mounting designed to be regulated angularly at the periphery of the rotor. However, this arrangement does not make it possible to achieve the results obtained with the present invention.
SUMMARY AND OBJECTS OF THE INVENTION
In essence, according to the invention a teaseling machine—of the type comprising a rotor to which the fabric being processed is fed and from which it is drawn, and arranged in which rotor, at regular intervals around the periphery, are a plurality of revolving cylinders provided with teaseling or brushing clothing acting on the contacting fabric which is slightly deflected by adjacent cylinders—is characterized in that it comprises, in the space between adjacent cylinders, a deflecting means that extends parallel to the axis of the rotor and to the axis of the cylinders and that can be adjusted radially relative to the rotor so that it produces an adjustable deflection of the span of fabric between one cylinder and the next, thereby varying the teaseling action of the cylinder clothings.
Said deflecting means may advantageously be in the form of revolving rollers that are also free to revolve under the action of the fabric with which they come into contact.
The machine may comprise means for the simultaneous control of all of said deflecting means. Said deflecting means may be mounted on bearings supported on eccentrics or cranks or the like controlled by a control system common to all of these, such as a ring gear, a chain or the like.
A teaseling machine according to the invention can employ clothings for the teaseling cylinders composed of thin flexible wires that may be of relatively great length. The cylinders may possess teaseling clothings or abrasive coverings of differing characteristics.
A clearer understanding of the invention will be gained from the description and the accompanying drawing, which latter shows a practical, non-restrictive example of said invention.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a diagram of a conventional teaseling machine of the type indicated earlier;
FIGS. 2 and 3 show an enlarged detail of the perimeter of a rotor constructed in accordance with the invention, in two different conditions of the apparatus that varies the position of the fabric with respect to the teaseling cylinders; and
FIGS. 4 and 5 show possible modified schematic embodiments of the adjustment system according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As illustrated in the accompanying drawing, and referring initially to FIG. 1, the number 1 denotes a rotor around which the fabric T arriving in the direction of arrow f 1 is deflected at a deflecting roll 3 , while 5 denotes another deflecting roll around which the fabric is deflected so as to be removed in the direction of arrow f 3 . The rotor has a plurality of teaseling cylinders 7 around its perimeter and these are made to revolve, each around its own axis in the same direction or in opposing directions either between one cylinder and the next or with respect to the direction of rotation of the rotor 1 . This arrangement, which is known per se, is modified in accordance with the invention as follows, reference being made in particular to FIGS. 2 and 3.
FIG. 2 shows the position adopted by the fabric T when the apparatus in accordance with the invention is inactive. The fabric T travels between one teaseling cylinder 7 and the next along a rectilinear span T 1 and is deflected by each cylinder through an angle αT which is fixed in the conventional arrangement of this teaseling machine shown schematically in FIG. 1 . Since the deflection imposed by each teaseling cylinder 7 is fixed—in the conventional arrangement shown in FIG. 1 —the teaseling action can in practice be modified only by varying the relative speeds of the cylinders and of the rotor and by varying the tension applied to the fabric in its path around the rotor 1 .
By contrast, in accordance with the invention and with the diagrams of FIGS. 2 and 3, between each pair of adjacent cylinders 7 , or between certain of the adjacent cylinders 7 is a deflecting means 9 which in the form shown in FIGS. 2 and 3 consists of a roller capable of revolving idly or otherwise with its axis parallel to that of the cylinders 7 and the rotor 1 . The position of the deflecting roller 9 can be modified in the radial direction relative to the rotor 1 , as indicated by the line R—R in FIGS. 2 and 3, by, for example, providing guide means 12 on the structure of the rotor 1 for sliding members which are adjusted for position with an adjustment facility that may be very fine, and then locked to support their respective rollers 9 in a number of positions, which may be varied between an inactive position as shown in FIG. 2 —where the deflecting rollers 9 do not influence the path of the span T 1 of the fabric between two cylinders 7 in which the deflecting roller 9 is placed —to one or more positions projecting beyond the path T 1 so as to alter this path between two adjacent teaseling cylinders 7 (FIG. 3 ). In the inactive position of a roller 9 , the deflection of the fabric by a teaseling cylinder 7 is labelled αT.
By positioning a deflecting roller 9 so as to interfere with the path T 1 , the span between one teaseling cylinder 7 and the adjacent cylinder 7 is deflected in such a way that the angle of deflection imposed by the teaseling cylinders 7 is modified; basically, the arc of deflection and of contact of the fabric T on the teaseling cylinders 7 between which the deflecting roller 9 is positioned is modified in such a way as to interfere with the span T 1 , as can be seen by comparing FIGS. 2 and 3 : in FIG. 3 the angle of deflection imposed by each teaseling cylinder 7 (when a deflecting roller 9 is interfering with the path T 1 ) is an angle βT that is less than the angle αT and that is adjustable by means of the centrifugal movement of the deflecting roller 9 .
With this arrangement it is therefore possible to vary the action of the clothing of each teaseling cylinder 7 on the fabric without changing the clothing.
In particular with the arrangement in accordance with the invention it is possible to use teaseling cylinders with a clothing that may be of a type having even quite long springy metal wires, by adjusting the deflecting rollers 9 so as to prevent an excess of flexibility of the clothing or metal brushes, by adjusting the incidence, that is the interference, and the arc of fabric supported by the clothings of the teaseling cylinders 7 .
In essence it is possible to adjust the incidence of the fabric, i.e. the deflection of the fabric, on the individual teaseling cylinders 7 . It is consequently also possible to use both paper or abrasive textile clothings and clothings with metal brushes having more than usually tall flexible filaments without the danger that the individual flexible wires will be bent and therefore prone to being deformed and becoming unusable; instead the fact that the deflecting means such as the rollers 9 can be adjusted also means that these types of brushes composed of metal or synthetic composite filaments or abrasive belts are useable. It is also possible to use teaseling l cylinders of different kinds alternating with each other by appropriate and selective adjustment of each of the deflecting means such as the deflecting rollers 9 .
Where it is wished to allow for simultaneous and identical adjustment of all deflecting means such as the rollers 9 , the rollers 9 may be mounted idly on spindles 9 A eccentrically with respect to supporting shafts 9 B as indicated in FIG. 5, the angular positions of the eccentrics 9 A of the various rollers being modifiable by a single system that controls the angular adjustment of the eccentrics 9 A. As a further alternative to the versions illustrated in FIGS. 2, 3 on the one hand and 5 on the other, each of the deflecting cylinders 9 can be mounted on a crank 9 C that can be rotated about the axis of one of the teaseling cylinders 7 between which the means 9 is located; here again, angular control of the position of the crank 9 C can be achieved on all the cranks or some of the cranks through a single control member, e.g. a ring gear, a toothed belt or the like.
Each deflecting means 9 may also be constructed differently from the form of an idle roller as illustrated in the drawing.
It will be understood that the drawing shows only an example given purely as a practical demonstration of the invention, which latter can be varied as regards shapes and arrangements without thereby departing from the scope of the concept on which said invention is based.
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The teaseling machine, comprising a rotor, arranged at regular intervals around the periphery of which are a plurality of revolving cylinders with teaseling clothing, has, in the space between adjacent teaseling cylinders, a deflecting cylinder that extends parallel to the axis of the rotor and to the axis of the cylinders and that can be adjusted radially relative to the rotor so that it produces an adjustable deflection of the span of fabric between one cylinder and the next, thereby varying the teaseling or brushing action of the cylinder clothings.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The current application claims the benefit of co-pending U.S. Provisional Application No. 60/488,913 filed Jul. 21, 2003, which is hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] (1) Technical Field
[0003] The present invention relates generally to storage devices and more particularly to a storage device capable of rapid and substantially full inversion, thereby releasing its contents.
[0004] (2) Related Art
[0005] Pockets and pocket-like storage devices have long been used as a method of transporting items. Generally, removal of the contents of a pocket requires a user to place his or her hand into the pocket, grasp the item or items, and remove the item or items from the pocket.
[0006] In many circumstances, such a method of removal is sufficient. However, an alternate method of removal is desirable when (1) removal of the item or items must be done quickly, (2) grasping an item or items would be difficult, and/or (3) complete removal of an item or items would be difficult or time consuming. Thus, a need exists for a storage device permitting the rapid and complete removal of its contents.
SUMMARY OF THE INVENTION
[0007] The claimed invention discloses a storage device capable of rapid and substantially full inversion, permitting the rapid and substantially complete removal of its contents. Such a storage device is useful when its contents must be quickly removed, including, for example, where the storage device contains equipment useful to an emergency responder such as a police officer, a firefighter, or a paramedic. Such a storage device is also useful where its contents are otherwise difficult to remove, as where the contents include liquids or many small objects.
[0008] In a first embodiment, the claimed invention discloses a storage device comprising an outer container forming an exterior and an interior, an inner container having a first portion that is attached to the outer container and a second portion that is disposed on the interior, and an exterior inversion means that allows a user to invert the second portion of the inner container to reside substantially on the exterior.
[0009] In a second embodiment, the claimed invention discloses an apparatus comprising means for carrying the apparatus, a storage means comprising an outer container forming an exterior and an interior and an inner container having a first portion that is attached to the outer container and a second portion that is disposed in the interior, and an exterior inversion means that allows a user to invert the second portion of the inner container to reside substantially outside the outer container.
[0010] In a third embodiment, the claimed invention discloses a storage device comprising a member having a first side and a second side and an aperture between, a container having a first portion that is attached around the aperture on the first side of the member and a second portion that is unattached to the member, and an inversion means that allows a user from the second side to invert the second portion of the container, moving it from the first side of the member to the second side of the member.
[0011] The foregoing and other features of the invention will be apparent from the following more particular description of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The embodiments of this invention will be described in detail, with reference to the following figures, wherein like designations denote like elements, and wherein:
[0013] FIG. 1 shows an inverted storage device according to a first embodiment of the claimed invention.
[0014] FIG. 2 shows a closed storage device according to a second embodiment of the claimed invention.
[0015] FIGS. 3A-3C show the various conformations of a third embodiment of the claimed invention.
[0016] FIG. 4 shows a vest having two storage devices according to a fourth embodiment of the claimed invention.
[0017] FIG. 5 shows a storage device according to a fifth embodiment of the claimed invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring to FIG. 1 , storage device 1 comprises outer container 10 , inner container 20 , and inversion means 30 . As depicted, inversion means 30 is an elongate member attached at one end to a surface of inner container 20 . Preferably, where inversion means 30 is an elongate member, inversion means 30 is configured to extend beyond a surface of outer container 10 when inner container 20 is not inverted and residing within outer container 10 . Optionally, where inversion means 30 is an elongate member, a handle 32 may be attached at or near an end opposite the end attached to a surface of inner container 20 .
[0019] A first portion of inner container 20 is attached to an interior or exterior surface of outer container 10 while a second portion of inner container 20 is disposed adjacent an interior surface of outer container 20 , such that the second portion of inner container 20 may be inverted by means of inversion means 30 and made to substantially reside adjacent an exterior surface of outer container 10 , as shown in FIG. 1 .
[0020] First portion of inner container 20 may be attached to a portion of outer container 10 and inversion means 30 may be attached to a portion of inner container 20 by any means known in the art. In one embodiment, such attachments are of sufficient strength as to permit inversion of inner container 20 without detachment of inner container 20 from outer container 10 or inversion means 30 from inner container 20 . Suitable attachment means include stitching and adhesives.
[0021] Outer container 10 , inner container 20 , and inversion means 30 may be of any materials known in the art, including cotton, silk, wool, nylon, polyester, or rayon. In addition, outer container 10 , inner container 20 , and/or inversion means 30 may be of the same or different materials.
[0022] Handle 32 may be of any material known in the art, including wood, plastic, ceramic, or metal. In one embodiment, handle 32 is a rigid material. Where inversion means 30 is an elongate member, a portion of which extends beyond an edge of outer container 10 , handle 32 preferably provides added weight to the elongate member, so as to locate inversion means 30 in an area outside of outer container 10 that is predictable by a user. For example, where storage device 1 is configured to be oriented in a substantially horizontal direction, handle 32 preferably provides sufficient weight to an end of inversion means 30 that a portion of inversion means 30 will normally be located below storage device 1 . This orientation is depicted most clearly in FIG. 3A . Optionally, handle 32 may be a loop, knot, or similar structure formed in elongate member.
[0023] Referring to FIG. 2 , storage device 100 is depicted in a closed position, wherein inner container (not shown) resides substantially within outer container 110 . In one embodiment, a portion of inversion means 130 , again depicted as an elongate member with handle 132 , resides on the exterior of outer container 110 .
[0024] In one embodiment, from its closed position, storage device 100 is preferably made to release its contents by a user grasping and pulling a portion of inversion means 130 in a direction away from the openings of outer container 110 and inner container. Upon such action, storage device 100 adopts a conformation similar to that depicted in FIG. 1 , wherein inner container 20 is substantially inverted to reside outside outer container 10 .
[0025] In one embodiment, storage device 100 may contain a lid 112 and attachment means 114 . Attachment means 114 may be of any kind known in the art, including hooks-and-loops, snaps, etc., provided that attachment means 114 do not prevent or substantially interfere with inversion of inner container or the release of its contents. Attachment means 114 may be located on lid 112 , outer container 110 , or both.
[0026] Referring to FIGS. 3A through 3C , storage device 200 is depicted in the various conformations it will adopt in transitioning from its closed position ( FIG. 3A ) to its inverted position ( FIG. 3C ). As depicted in FIGS. 3A through 3C , storage device 200 is oriented in a substantially horizontal direction, as it may be oriented on an article of clothing or carrying means, such as a backpack. Storage device 200 may similarly be oriented in a substantially vertical direction, with an opening in outer container 210 facing either upward or downward.
[0027] Referring now to FIG. 3A , storage device 200 again consists of outer container 210 , an inner container (not shown), and an inversion means 230 . As depicted, inversion means 230 consists of an elongate member and handle 232 , wherein a portion of elongate member extends beyond an edge of outer container 210 . As depicted, storage device 200 further comprises a lid 212 and attachment means 214 . Attachment means 214 attaches a portion of lid 212 to a portion of outer container 210 .
[0028] Referring now to FIG. 3B , upon applying a directional force F upon inversion means 230 , attachment means 214 is released from at least one of lid 212 and outer container 210 . As depicted, attachment means 214 is released from outer container 210 .
[0029] Referring now to FIG. 3C , upon continued application of directional force F upon inversion means 230 , inner container 220 is inverted from its position within outer container 210 . Upon inversion of inner container 220 , its contents are moved to a location outside both outer container 210 and inner container 220 .
[0030] Referring to FIG. 4 , a vest 300 is shown having two storage devices 302 , 304 located on an outer surface of its left front side. First storage device 302 is located on the left breast of vest 300 and is oriented with its opening facing downward. As depicted, inner container 320 has been inverted to reside substantially outside outer container 310 . Inversion means 330 is shown as an elongate member with optional handle 332 .
[0031] Second storage device 304 is located on the left front of vest 300 at approximately waist level and is oriented in a horizontal direction with its opening facing medially. As depicted, lid 312 covers the opening to outer container 310 and is attached to outer container 310 by attachment means 314 . Inversion means 330 is shown as an elongate member with optional handle 332 , a portion of elongate member extending beyond an edge of outer container 310 .
[0032] Although depicted as a vest, any similar article of clothing or carrying means could similarly be used, including a jacket, coat, shirt, pair of pants, backpack, book bag, handbag, shoulder bag, messenger bag, duffle bag, tote bag, or fanny pack. Where storage device is located on an article of clothing or a carrying means, it may be fixedly or non-fixedly attached. Methods of attachment can be any known in the art, including stitching, adhesives, zippers, buttons, snaps, ties, loops, hooks-and-loops, or clips.
[0033] Referring to FIGS. 5A and 5B , storage device 400 comprises container 420 , inversion means 430 , and a member 410 having a first side 416 , a second side 417 , and an aperture 418 therebetween. As such, the illustrative embodiment of the invention depicted in FIGS. 5A and 5B is similar to the embodiments described above, with the exception that member 410 need not be a container. That is, member 410 need not be able to hold container 420 . For example, member 410 may be the material comprising the leg of a pair of pants, vest, etc., wherein container 420 resides on one or the other side of the leg material.
[0034] Referring to FIG. 5A , container 420 is attached around aperture 418 on second side 417 of member 410 . Inversion means 430 is shown as an elongate member attached to a surface of container 420 and extending beyond first side 416 of member 410 . Optional handle 432 is shown as a loop formed in inversion means 430 . Application of directional force F results in the substantial inversion of container 420 , as depicted in FIG. 5B . Once substantially inverted, the portion of container 420 not attached to second side 417 of member 410 resides adjacent to first side 416 of member 410 .
[0035] While this invention has been described in conjunction with the specific embodiments outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the embodiments of the invention as set forth above are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.
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The claimed invention discloses a storage device capable of rapid and substantially full inversion, permitting the rapid and substantially complete removal of its contents. Such a storage device is useful when its contents must be quickly removed, including, for example, where the storage device contains equipment useful to an emergency responder such as a police officer, a firefighter, or a paramedic. Such a storage device is also useful where its contents are otherwise difficult to remove, as where the contents include liquids or many small objects, such as grains of sand.
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FIELD OF INVENTION
[0001] The present invention discloses a process for modulating the growth of body and/or head/cranial hair on mammalian organisms, for example humans, by administering thereto, whether topically and/or systemically, therapeutically effective amounts of at least one cannabinoid modulators, in combination with or without other suitable therapeutically active agents.
BACKGROUND AND PRIOR ART
[0002] Cannabinoids are present in Indian hemp Cannabis saliva and have been well known for their medicinal properties for ages. Cannabinoids as a therapeutic agents is however a recent phenomenon. (Williamson E. M. & Evans E. J. Drugs 2000 December; 60(6): 1303-14) Research in this area over the last decade have provided very important information on the cannabinoid receptors and their agonists and antagonists.
[0003] There has been an increased interest among the different pharmaceutical companies in developing drugs for the treatment of diseases connected with disorders of the cannabinoid systems (Greenberg D. A, Drugs News & Perspectives 1999; 12: 458; Kulkarni S. K. & Ninan, Indian Journal of Pharmacology 2001; 33; 170-184; Piomelli D et. al., Trends Pharmacol Sci. 2000 June; 21(6); 218-24). Several compounds which are either CB 1 , CB 2 &/or CB 3 antagonists have been reported and are under various stages of development for e.g. SR-141716 A (Sanofi), CP-272871 (Pfizer), LY-320135 (Eli Lily), AM-630 (Alexis), SR-144528 (Sanofi) etc.
[0004] Compounds which mimic the actions of the cannabinoids are useful for preventing or reversing the symptoms that can be treated with cannabis, some of its derivatives, and synthetic cannabinoids in a human or other mammalian subject. Thus compounds which are modulators of cannabinoid receptors are known to be useful in the treatment or amelioration of disorders, in mammals, such as (a) pulmonary disorders including asthma, chronic bronchitis; (b) ocular disorders such as glaucoma; (c) allergies and allergic reactions; (d) inflammatory conditions like arthritis, inflammatory bowel disease; (e) pain, (f) immune system disorders like AIDS, lupus; (g) allograft rejections; (h) central nervous system disorders like Torette's syndrome, Parkinson's disease, Huntington's disease, epilepsy, various psychotic disorders like depression, manic depression etc.; (i) vomiting, nausea and vertigo; (O) obesity; (k) cognitive disorders such as Alzheimer's disease; (1) schizophrenia; (m) smoking cessation
[0005] Use of cyclooxygenase or a lipoxygenase inhibitor as hair growth modulators have been described in U.S. Pat. No. 6,465,421 & U.S. Pat. No. 5,928,654.
[0006] We herein disclose compounds, which are cannabinoid receptors ligands, as hair growth modulators suitable for use in mammals either alone or in combination with other suitable therapeutically active agents.
DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0007] FIGS. 1 and 2 : Effect of Compound 2 on Hair Growth in C57BL/6J Mice
DETAILED DESCRIPTION
[0008] The present invention discloses compounds, which are cannabinoid receptors ligands, suitable for modulating hair growth in mammals. Several compounds which act as cannabinoid receptors ligands, their preparation and their use in medicine have been reported in U.S. 20050101592, U.S. 20050096379, U.S. Pat. No. 5,925,768, U.S. Pat. No. 6,344,474, U.S. Pat. No. 6,028,084, U.S. Pat. No. 5,462,960, EP 0656354, U.S. Pat. No. 6,432,984, U.S. Pat. No. 6,509,367, U.S. Pat. No. 5,624,941, U.S. 20010053788, U.S. Pat. No. 6,476,060, U.S. 2004039024, EP1230222, EP 122952, FR 2816938, FR 2761266, FR 2800375, EP 0656354, EP 0576357, WO 0170700, WO 02076949, WO 2005044822, WO 2004096801, WO 2004094429, WO 2004096794, WO 2004094421, WO 2004094417, WO 2004096763, WO 200435566, WO 2004048317, WO 2004037823, WO 2004017920, WO 2004029204, WO 2004026301, WO 2004021974, WO 03082833, WO 03027076, WO 03026648, WO 03026647, WO 03020217, WO 03082191, WO 03084930, WO 03084943, WO 0228346, WO 0158450, WO 0185092, WO 0132663, WO 0132629, WO 9719063. Other compounds having similar activity have been disclosed in J Pharmacology & Experimental Therapeutics, 2003, 306(1), 363-370; Bioorganic Medicinal Chemistry, 1997, 5, 1591-1600; J Med. Chem. 1999, 42, 769-776; Bioorg. Med. Chem. Lett., 1999, 9, 2233-2236; Bioorg. Med. Chem. 2003, 11, 251-263; Bioorg. Med. Chem. 2003, 11, 3121-3132; Bioorg. Med. Chem. 2004, 12, 393-404, J Biological Chemistry, 1996, 271, 6941-6946; J. Med. Chem., 2002, 45, 1748-1756; J. Med. Chem., 2002, 45, 2708-2719; J Med. Chem., 2002, 45, 3649-3659; J Med. Chem., 2002, 45, 1447-1459; J. Med. Chem., 2003, 46, 642-645; J. Med. Chem., 2004, 47, 627-643; J Pharmacology & Experimental Therapeutics, 2002, 301(3), 963-968; Molecular Pharmacology, 2002, 62(6), 1274-1287; Drugs Fut., 2002, 27 (Suppl. A): XVIIth Int. Symposium on Medicinal Chemistry, Chem. Pharm. Bull., 2002, 50, 1109-1113. However, use of such compounds as modulators of hair growth has not been envisaged.
[0009] In a specific embodiment, the present invention discloses use of compounds disclosed in any of the above references or pharmaceutical compositions containing them as modulators of hair growth in mammals either alone or in combination with one or more other suitable therapeutic agents.
[0010] A “cannabinoid receptor ligand” according to the present invention includes a cannabinoid receptor antagonist, agonist or an inverse agonist.
[0011] A “hair growth modulator” according to the present invention includes a compound which hair growth stimulant or a repressant.
[0012] In a further embodiment the present invention provides method of modulating hair growth in mammals by treatment with compounds which axe ligands of the cannabinoid receptors.
[0013] In one of its embodiments the suitable cannabinoid receptor ligands for use according to the present invention bind to CB 1 , CB 2 and/or CB 3 receptors.
[0014] In a preferred embodiment, the compounds may be selected from the group which are preferentially antagonist or an inverse agonists of the CB 1 receptor.
[0015] Non-limiting examples of cannabinoid receptor ligands are Rimonabant or its analogues, SLV-319 and the like.
[0016] In a further embodiment, the present invention discloses compound of formula (I) or pharmaceutical composition containing the same, as modulators of hair growth in mammals,
wherein,
R 1 represents substituted or unsubstituted groups selected from (C 3 -C 7 )cycloalkyl, (C 3 -C 7 )cycloalkenyl, bicycloalkyl, bicycloalkenyl, aryl, aralkyl, heterocyclyl, heteroaryl, heterocyclyl(C1-C 12 )alkyl & heteroar(C 1 -C 12 )alkyl; R 2 represents a substituted or unsubstituted single or used heteroaromatic or a heterocyclic group containing one or more heteroatoms selected from N, O or S; R 3 represents hydrogen, halo, cyano, nitro, (C 1 -C 12 ) substituted or unsubstituted alkyl, (C 1 -C 12 ) substituted or unsubstituted haloalkyl, hydroxyalkyl, cycloalkyl, alkylsulfonyl groups; X is either a direct bond or a group —(CH 2 ) n N(R 4 )—, wherein R 4 is H, or a (C 1 -C 3 )alkyl and n is 0-2; R represents —NR 5 R 6 where R 5 is either H or (C 1 -C 6 )alkyl; R 6 is
where R a is (C 1 -C 6 )alkyl or R a forms a bridge with one of the atoms of the heterocyclic radical formed by —NR b Rc;
R b and R o represents substituted or unsubstituted groups selected from alkyl, aralkyl or alkenyl or R b & R c together with the nitrogen atom to which they are bonded, form a 5 to 8 membered saturated or unsaturated heterocyclic radical which may be optionally substituted and may be fused.
[0023] In yet another embodiment, the present invention discloses compound of formula (Ia) or pharmaceutical composition containing the same, as regulators/promoters/stimulators of hair growth in mammals,
wherein,
‘R 7 ’ and ‘R 8 ’ are the same or different and represent phenyl, thienyl or pyridyl groups, which may be optionally substituted with 1-3 substituents Y, which may be same or different and selected from the group C 1-3 -alkyl or alkoxy, hydroxy, halogen, trifluoromethyl, trifluromethylthio, trifluromethoxy, nitro, amino, mono- or dialkyl (C 1-2 )-amino, mono- or dialkyl (C 1-3 )-alkyl sulfonyl, dimethylsulfamido, C 1-3 -alkoxycarbonyl, carboxyl, trifluromethylsulfonyl, cyano, carbamoyl and acetyl, or R 7 and/or & represent naphtyl; ‘R 9 ’ represents hydrogen, hydroxy, C 1-3 -alkoxy, acetyloxy or propionyloxy;
‘Aa’ represents one of the groups (i), (ii), (iii), (iv) or (v)
wherein
‘R 11 ’ and ‘R 12 ’ independently of each other represent hydrogen or C 1-8 branched or unbranched alkyl or C 3-8 cycloalkyl or ‘R 11 ’ represents acetamido or dimethylamino or 2,2,2-trifluroethyl or phenyl or pyridyl with the proviso that R 12 represents hydrogen ‘R 13 ’ represents hydrogen or C 1-3 unbranched alkyl; ‘Bb’ represents sulfonyl or carbonyl; ‘R 10 ’ represents benzyl, phenyl, thienyl or pyridyl which may be substituted with 1,2 or 3 substitutents Y, which can be the same or different, or ‘R 10 ’ represents C 1-8 branched or unbranched alkyl or C 3-6 cycloalkyl, or ‘R 10 ’ represents naphthyl.
[0030] The present invention also envisages the use of compounds, which are potentially suitable as cannabinoid receptors ligands as modulators of hair growth in mammals.
[0031] The present invention also discloses use of cannabinoid receptors ligands, in combination with other suitable therapeutically active agents for e.g. an inhibitor of cyclooxygenase or 5-lipoxygenase, or other hair growth modulators as are known in the art, as modulators of hair growth in mammals. Preferably, the other therapeutically active agent may be selected from Dutasteride, Finasteride, Minoxidil, Fluorominoxidil, Fluridil, Viprostol, Trequinsin hydrochloride, Namindil and Procyanidin B-2.
[0032] The quantity of active component, according to the present invention, in the pharmaceutical composition and unit dosage form thereof may be varied or adjusted widely depending upon the particular application method, the potency of the particular compound and the desired concentration. Generally, the quantity of active component will range between 0.5% to 90% by weight of the composition.
[0033] The precise dose and method of administration of cannabinoid receptors ligands to be used according to the present invention, will be determined by a number of factors, which will be apparent to those skilled in the art, in light of the disclosure herein.
[0034] Any suitable cannabinoid receptors ligands may be employed. A cannabinoid receptors ligands will be suitable if:
(a) at the dose and method of administration to the mammalian subject, it is not acutely toxic, and does not result in chronic toxicity disproportionate to the therapeutic benefit derived from treatment; and (b) at the dose and method of administration to the mammalian subject it modulates hair growth in the subject.
[0037] Methods for conducting toxicity studies are known in the art.
[0038] The patient is preferably mammalian. In one embodiment the patient in which hair growth is modulated is a human. In another embodiment, it is a domestic animal such as cat, dog or horse.
[0039] In one embodiment of the invention, there is provided a method of modulating hair growth in mammalian patient in need thereof. The method comprises: selecting a patient in need of modulating hair growth, and administering a suitable cannabinoid receptor ligand.
[0040] In an embodiment is provided a topical formulation comprising atleast one caunabinoid receptor ligand, as a hair growth stimulant. The topical formulation may optionally contain one or more further hair growth stimulant. The formulation may further comprise other pharmaceutically acceptable excipients, suitable for suitably formulating the composition. The formulation may be prepared by techniques known in the art.
[0041] In one embodiment of the invention, there is provided a kit containing a cannabinoid receptor ligand and a pharmaceutically acceptable excipient. In one embodiment, the kit further comprises of, instnrctions for administering the cannabinoid receptor ligand to modulate hair growth in a mammalian subject. In yet another embodiment the kit still further comprises a means to administer the cannabinoid receptor ligand. Such kits may be prepared by techniques known.
[0042] Representative compounds suitable for carrying out the present invention includes;
Compound Structure IUPAC name Compound 1 Hydrochloride salt of 5-(5-Chloro- thiophen-2-yl)-1-(2,4-dichloro- phenyl)-4-methyl-1H-pyrazole-3- caxboxylic acid piperidin-1-ylamide Compound 2 5-(4-Chloro-phenyl)-1-(2,4-dichloro- phenyl)-1H-pyrazole-3-carboxylic acid ethyl ester Compound 3 4-Chloro-N-{[3-(4-chloro-phenyl)-4- phenyl-4,5-dihydro-pyrazol-1-yl]- methylamino-methylene}-benzene sulfonamide Compound 4 4-Chloro-N-{[3-(4-chloro-phenyl)-4- phenyl-4,5-dihydro-pyrazol-1-yl]- methylamino-methylene}-benzene sulfonamide
[0043] The present invention is illustrated by the following examples, which are provided for the sake of illustrations only and should not be construed as limiting the scope of the invention in any way.
EXAMPLE
Effect of Compound 1 and Compound 2 on Hair Growth and Body Weight in Male C57BL/6 Mice
[0044] The C57BL/6 mice were housed on a lightdark cycle in a room with temperature (22±2° C.) and humidity control. They were fed either a high-fat diet (HFD) (49% fat, 18% protein, 33% carbohydrate) or a standard mouse diet (STD) (8% fat, 19% protein, 73% carbohydrate). Six-week-old C57BL/6J male mice were given HFD or STD diets for 17 wks before drug treatment started. This diet treatment caused significantly higher body weight gain in high-fat fed male animals as compared to normal diet animals. Simultaneously, the animals in the high fat diet fed group showed significant loss of body hair, especially on the back. After this, mice were weighed and treated as per the following three groups, while the diet treatment continued.
[0045] High-fat diet fed & vehicle treated (HFD-V),
High-fat diet fed & treated with 10 mg/kg Compound 2 (HFD-R 10 mg) High-fat diet fed & treated with 10 mg/kg Compound 1 (HD-ZY 10 mg) Compound 1 and Compound 2 were administered orally in distilled water with 0.1% Tween 80 one hour before the onset of the dark phase.
[0049] The animals were observed daily. Body weights were recorded daily, and the animals were photographed on 28 th day on the back, The results are mentioned in Table 1 and Table 2. It indicates that the treatment with 10 mg/kg Compound 1, has significantly enhanced the growth of body hair. The same treatment has resulted decrease in body weight.
TABLE 1 Effect of different treatments on the hair growth on male C57BL/6J mice Table indicate the bald area (where hair growth or pigmentation has not appeared) after 28 th day of dosing (n = 6) Group Area (cm 2 ) (Mean ± Standard Error Mean) HFD-V 0.346 ± 0.079 HFD-Compound 2 0.156 ± 0.068 HFD- Compound 1 0.011 ± 0.223
[0050]
TABLE 2
Effect of different treatments on the body
weight in male C57BL/6J mice (n = 6)
Group
Body Weight on Day 0 (g)
HFD-V
30.5 ± 1.3
HFD- Compound 2
30.5 ± 1.6
HFD- Compound 1
29.2 ± 1.1
Body Weight on Day 28 (g)
HFD-V
29.7 ± 1.1
HFD- Compound 2
27.1 ± 1.1
HFD- Compound 1
26.9 ± 1.1
Change in Body Weight (g) in 28 days versus Day 0
HFD-V
−0.8 ± 0.4
HFD- Compound 2
−3.5 ± 0.8
HFD- Compound 1
−1.7 ± 0.5
Change in Body Weight (g) versus HFD-V
HFD-V
HFD- Compound 2
−9.7 ± 2.8
HFD- Compound 1
−3.3 ± 1.8
[0051] These data indicate that compound 1 and compound 2 are able to stimulate hair growth in addition to decreasing body weight.
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The present invention discloses method for modulating the growth of body and/or head/cranial hair on mammalian organisms, for example humans, by administering thereto, whether topically and/or systemically, therapeutically effective amounts of at least one cannabinoid ligands, in combination with or without other suitable therapeutically active agents.
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This application is a continuation of application Ser. No. 934,581 filed on Nov. 25, 1986, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to thermoplastic shrink films, and particularly thermoplastic shrink films which provide a very high oxygen barrier. More particularly, this invention relates to a thermoplastic coextruded oriented shrink film which provides very high oxygen barrier properties.
Ethylene vinyl alcohol copolymer (EVOH) is well known as an oxygen barrier resin suitable for use in multi-layer films. It is also recognized that vinylidene chloride copolymers, commonly known as SARAN also exhibit oxygen barrier characteristics in a multi-layer film. However, the characteristics of these barrier materials are such that their effectiveness as oxygen barriers is effected by the humidity of the environment in which the film is used, i.e. the barrier properties of these barrier materials are humidity sensitive. The dependence of EVOH on humidity in estimating its gas barrier properties is discussed in the article Ethylene Vinyl Alcohol Resins for Gas-Barrier Material by T. Iwanami and Y. Hirai. This article discusses the degradation in oxygen barrier properties of the EVOH as humidity increases.
Vinylidene chloride copolymers (SARAN) typically exhibit the opposite behavior, with oxygen barrier properties improving somewhat with an increase in humidity conditions.
The combination of EVOH and saran in a coextruded multi-layer film is therefore desirable. This would reduce the overall effect of changes in humidity on the oxygen barrier characteristics of the film.
An additional problem in the use of EVOH, with or without a separate saran layer in a multi-layer structure, is.the cracking problem associated with EVOH. In the past, this cracking problem has been somewhat alleviated by blending EVOH with nylon. The nylon also contributes to ease in orientation of a film containing an EVOH resin. Such processing advantages are made, however, at the expense of higher oxygen transmission rates of EVOH/nylon blends compared with EVOH alone.
Still another problem with unblended EVOH is the difficulty in orienting coextruded EVOH out of a hot water system where EVOH is an inner layer. The EVOH has significantly higher orientation temperature ranges than saran, and when both materials are utilized within a single multi-layer film, an incompatibility in orientation temperature ranges results. While a saran material orients relatively easy after being passed through a hot water system, the EVOH inner layer does not respond as well, and difficulty in orientation results. This is particularly true in the blown bubble technique for orientation well known in the art for producing biaxially oriented film useful in many shrink film applications.
An additional problem with "trapped" EVOH, i.e. EVOH forming an interior layer of a multi-layer structure is the difficulty in removing water from the layer once wetting has occurred. Of course, this difficulty in drying trapped EVOH results in a corresponding loss in oxygen barrier properties because of the poorer barrier performance of EVOH at higher relative humidities.
A past solution to the problem of orienting EVOH out of hot water has been the use of relatively high mole percents of ethylene in the EVOH copolymer. Typically, EVOH resins having between 32 and 38 mole percent ethylene have been employed, and especially those at the higher end of this range, to permit EVOH to approach more closely the orientation characteristics of ethylene vinyl acetate copolymer, and therefore orient more easily.
While the higher ethylene content EVOH resins solve to some extent the problem of orienting an EVOH containing film out of hot water, they also suffer from the disadvantage of reduced barrier properties. As a general rule, the higher the ethylene content in the EVOH, the lower the oxygen barrier properties of the resin, in films employing the resin.
It has now been found that EVOH may be coextruded as an outside layer in a multi-layer film having for example at least one additional polyolefin layer and/or a saran layer, and the coextruded film can be passed through a hot water system and thereafter oriented. The EVOH is wetted and softened by the hot water during the passage of the coextruded film through the hot water. This wetting and softening effect significantly reduces the orientation temperature range of the EVOH to render it much more compatible with the saran layer of the structure if one is present, and in any case to lower the orientation temperature range of the EVOH significantly. Blending of minor amounts of nylon for processing purposes is unnecessary.
Such a reduction in the orientation temperature range of EVOH results in efficiencies in processing compared to a hot oil or hot air orienting system.
Although the EVOH is obviously wetted during the orientation process, its position as an outside layer of the multi-layer film permits relatively rapid drying of the same layer to substantially restore its oxygen barrier characteristics.
An additional advantage is that by employing this method, EVOH resins with a lower mole percent of ethylene can be used, and therefore a higher barrier EVOH resin can be employed.
For extrusion purposes, it is preferable to use a relatively high melt index EVOH resin as an outside layer. Melt indexes of at least 15 grams per 10 minutes (ASTM D-1238) and more preferably at least 20 grams per 10 minutes are preferred. With a melt index of less than about 15 grams per 10 minutes, extrusion becomes increasingly difficult. At melt indexes below about 10 grams per 10 minutes, coextrusion of a multi-layer film with the EVOH as an outside layer becomes very difficult or impossible.
It is an object of the present invention to provide a method of using lower ethylene content EVOH resins in multi-layer shrink films in order to obtain the better oxygen characteristics of these lower ethylene content resins.
Its a further object of the present invention to provide a method for orienting EVOH-containing multi-layer films at relatively low temperatures.
It is yet another object of the present invention to provide an EVOH-containing multi-layer oriented shrink film wherein the EVOH can dry relatively easily compared to trapped EVOH-containing structure.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a method of producing an oxygen barrier shrink film comprises coextruding a multi-layer film comprising an outside ethylene vinyl alcohol copolymer layer, and at least one layer bonded to the outside layer and comprising a polymeric material selected from the group consisting of a polyolefin or chemically modified polyolefin and a vinylidene chloride copolymer; and softening and wetting the ethylene vinyl alcohol copolymer layer by passing the coextruded film through hot water.
In another aspect of the present invention, a multi-layer oriented film is produced by the steps of coextruding a multi-layer extrudate comprising an ethylene vinyl alcohol copolymer as an outside layer, and at least one layer bonded to the outside layer and comprising a polymeric material selected from the group consisting of a polyolefin or chemically modified polyolefin and a vinylidene chloride copolymer; and softening and wetting the ethylene vinyl alcohol copolymer layer by passing the coextruded film through hot water.
Of interest is U.S. Pat. No. 4,576,988 issued to Tanaka et al and disclosing a melt molding material having a silicon-containing ethylene vinyl alcohol copolymer coated with vinylidene chloride.
Also of interest is UK Patent Application GB 2014476 A issued to Kuga et al and disclosing a substrate of polyvinyl alcohol coated on one or both sides with an aqueous dispersion of vinylidene chloride vinyl chloride copolymer.
Also of interest is UK Patent Application GB 2121062 A issued to Mollison disclosing a pouch made from a film comprising a laminate of a base film and a sealant fim. The base film may be a saponified ethylene vinyl acetate film. A layer of PVDC may be interposed between the base film and sealant film.
Also of interest is UK Patent Application No. GB 2106471 A issued to Maruhashi et al disclosing a vessel comprising one or more layers of ethylene vinyl alcohol copolymer coated with a vinylidene chloride copolymer layer.
DESCRIPTION OF THE DRAWINGS
In the sole drawing attached to this application and made a part of this disclosure:
FIG. 1. is a schematic cross-sectional view of a multi-layer film in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a schematic cross section of a multi-layer film is shown. Outside layer 10 comprises an ethylene vinyl alcohol copolymer having a melt index of at least about 10 grams per cubic centimeter, more preferably a melt index of at least about 15 grams per cubic centimeter, and most preferably a melt index of at least about 20 grams per cubic centimeter. Optionally, a nylon or nylon copolymer may be blended with the EVOH. Because of the advantages obtained by the present invention, EVOH resins with relatively low percentages of ethylene, and therefore higher oxygen barrier characteristics can be used in outside layer 10. Preferred ethylene contents range from 22 to 29 mole percent. EVOH resins having between 32 and 38 mole percent can also be used, but of course will provide relatively inferior barrier properties.
Layer 12 comprises a polyolefin or modified polyolefin. In the event that optional layers 14, 16, 18, and/or 20 are incorporated into the multi-layer film structure, layer 12 is preferably an anhydride-modified or otherwise chemically modified polyolefin which promotes adhesion between layer 14 and outside layer 10. These adhesives are commercially available from several suppliers including the Plexar series of adhesive resins from Norchem, the CXA series from DuPont, and Admer modified resins available from Mitsui Company. Layer 14 is preferably a barrier material, more preferably a saran. Both plasticized and unplasticized sarans are available.
Layer 16 preferably comprises polyolefin or a copolymer of ethylene with a comonomer such as vinyl acetate. Most preferably, layer 16 comprises a relatively high vinyl acetate EVA.
Layer 18 comprises a polyolefin or blend of polyolefins, and more preferably comprises a blend of polybutylene and polypropylene.
The outer layer 20 may comprise a polyolefin such as polypropylene.
As depicted in the drawing, only a relatively thin layer of the outside layer 10 is necessary to obtain the advantages of the invention.
The invention may be better understood with reference to the following examples given by way of illustration only.
EXAMPLE 1
A six layered structure was extruded by supplying six extruders. The first extruder which supplied the die orifice for the outside layer was provided with a blend of 90% EVOH (Soarnol ZL from Nippon Goshei) and 10% copolyamide (Grillon CA6). The EVOH had a melt index of 20 grams per 10 minutes.
The second extruder supplied the die orifice for the layer adjacent the outside layer with a modified ethylene vinyl acetate copolymer (CXA-E162 from DuPont).
The third extruder supplied a die orifice for the next layer and was provided with unplasticized SARAN (PV864 from Solvay). The SARAN was pre-blended with minor amounts of processing aids.
The fourth extruder supplied a die orifice for the next layer and was provided with ethylene vinyl acetate copolymer (Alathon 3170 from DuPont).
The fifth extruder supplied a die orifice for the next layer, and was provided with a blend of 50% ethylene propylene copolymer having about 3.8% ethylene by weight (Eltex KS 409x6206 from Soltex) and 50% polybutylene (PB 8640 from Shell).
The sixth extruder supplied the die orifice for the inside layer and was provided with ethylene propylene copolymer (Dypro from Cosden Chemical Company).
The various layers were coextruded through a die orifice as a tubular extrudate.
The tape was then quenched in a cold water bath, and passed to a hot water system. The entire film, including the outside blend layer containing the EVOH, was passed through the hot water. This step allowed the EVOH layer to be thoroughly wetted, and softened.
The coextruded film was then biaxially oriented using a blown bubble technique well known in the art.
EXAMPLE 2
A multi-layer oriented film substantially similar to that of example one, but having an outside layer of 100% EVOH (Soarnol ZL) was made under the same conditions as those described in example 1.
EXAMPLE 3
A multi-layer film similar to that of example 2 was made, with a relatively low melt index EVOH (EVAL EC-FlOl available from Eval Company of America). The resulting film had a poor outer surface (EVOH) because of the viscosity mismatch between the relatively viscous EVOH and the remainder of the film material.
The term "hot water" as used in the above examples refers primarily to water at or near its boiling point, i.e. in the vicinity of 180° to 212° F. However, this term is also used herein to describe embodiments in which water at lower temperatures is subsequently heated by some additional processing step. For example, in orienting a coextruded film, it is preferred that the water be at or near 212° F. However, water at lower temperatures could be used. After the tape is passed through the water bath, it may then be heated by passing the tape through a hot air oven or other heating means which will bring the tape up to its orientation temperature. In another embodiment, a thermoformable film constructed as described may be passed through a water bath at substantially room temperature, and then heated by suitable heating means at the beginning of a thermoforming operation.
It has been discovered that utilizing gan outside surface layer of EVOH provides oxygen barrier properties in the film, at relatively high humidities, which actually improve somewhat after the first two or three weeks. This is demonstrated by Table 1, showing dry and wet O 2 transmission readings for the films of Examples 1 and 2. The 100% RH readings run from Day 1 of testing to Day 23. Figures in parenthesis are gauge in mils. Oxygen transmission was measured in cubic centimeters, standard temperature and pressure (24 hours, square meter, atmosphere) according to ASTM D 3985.
TABLE I__________________________________________________________________________ EXAMPLE 1 EXAMPLE 2 SAMPLE 1 SAMPLE 2 SAMPLE 3 SAMPLE 1 SAMPLE 2 SAMPLE 3__________________________________________________________________________Oxygen Trans- 1.1(1.32) 1.2(2.10) 1.4(1.88) 0.7(2.54) 0.8(2.07) 1.4(1.21)mission at 73° F.,0% RHOxygen Trans-mission at 73° F.,100% RHDay 3 1.5(1.32) 0.4(2.10) 1.7(1.88) 1.5(2.54) 1.5(2.07) 2.8(1.21) 4 3.9 2.0 1.5 1.5 3.7 5.8 5 4.3 2.2 1.5 1.5 3.5 5.8 8 4.0 1.7 1.9 1.9 1.9 5.6 9 3.9 1.7 1.9 1.9 1.7 5.410 4.0 1.5 2.0 2.0 1.5 5.215 3.9 1.3 2.0 2.0 0.9 5.216 4.1 1.5 2.1 2.1 0.8 5.217 3.9 1.3 2.1 2.1 0.6 5.218 3.7 1.1 1.9 1.9 0.6 5.119 3.7 1.1 1.7 1.7 0.4 4.823 2.0 0.2 0.2 0.2 0.2 3.4__________________________________________________________________________
Another advantage of the use of EVOH as an outside layer of a multilayer film, oriented out of hot water, is the improvement in free shrink. It is believed that this improvement results from the softening and moisturizing action of the hot water on the EVOH as the tubular film is passed through the hot water bath. In Table 2, free shrink data for a film passed through hot water is compared with the same film passed through hot oil.
TABLE 2__________________________________________________________________________ EXAMPLE 1 EXAMPLE 2 EXAMPLE 1 EXAMPLE 2 (HOT WATER) (HOT WATER) (HOT OIL) (HOT OIL)__________________________________________________________________________Free Shrink %at 185° F.Av. Long. 19. 15. 16. 12.Std. Dev. 1. 2. 1. 1.95% C.L. 2. 3. 2. 1.Av. Trans. 22. 18. 16. 12.Std. Dev. 3. 2. 2. 3.95% C.L. 4. 3. 3. 5.Free Shrink (%)at 205° F.Av. Long 30. 27. 25. 22.Std. Dev. 3. 3. 2. 1.95% C.L. 5. 5. 3. 2.Av. Trans. 30. 28. 27. 26.Std. Dev. 3. 2. 2. 1.95% C.L. 5. 4. 3. 2.__________________________________________________________________________
Example 1 and 2 of Table 2 refer to the same materials as in Examples 1 and 2 of Table 1.
Free shrink was measured according to ASTM D 2732-70 (reapproved 1976).
All values in Table 2 are averages obtained from four (4) replicate measurements.
C.L. is confidence limit, e.g. if the reported average was 10, and the 95% C.L. was 2, then of 100 replicate readings, 95 would have a value between 8 and 12 inclusive.
Av. Long. represents average longitudinal direction free shrink. Av. Trans. represents average transverse direction free shrink.
Std. Dev. represents standard deviation.
It should be understood that the detailed description and specific examples which indicate the presently preferred embodiments of the invention are given by way of illustration only since various changes within the spirit and scope of the invention will become apparent to those of ordinary skill in the art upon review of the above detailed description. As an example, the outside wetted EVOH layer may be combined with one or more layers of various polymeric materials by coextrusion techniques in order to provide coextruded films useful in different packaging applications.
Additionally, although it is preferred for many applications to make use of an oriented film with substantial shrink characteristics, benefits can be obtained by wetting a coextruded tape in a hot water bath, the tape having an outside layer of EVOH, without the need for subsequent orientation.
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A method of producing an oxygen barrier film, and the resulting film, includes the coextrusion of a multi-layer extrudate having an outside ethylene vinyl alcohol copolymer layer which has been passed through a hot water system to soften and wet the ethylene vinyl alcohol copolymer. The wetted film can be more easily oriented to produce a shrinkable film.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser. No. 09/974,524, filed on Oct. 10, 2001, which is related to U.S. application Ser. No. 09/811,272, filed Mar. 17, 2001, entitled “Tools Used In Performing Femoral And Tibial Resection In Knee Surgery”, now abandoned; U.S. application Ser. No. 09/811,043, now U.S. Pat. No. 6,595,997, filed Mar. 17, 2001, entitled “Methods Used In Performing Femoral And Tibial Resection In Knee Surgery”; U.S. application Ser. No. 09/811,042, filed Mar. 17, 2001, entitled “Systems Used In Performing Femoral And Tibial Resection In Knee Surgery”; U.S. application Ser. No. 09/811,318, now U.S. Pat. No. 6,685,711, filed Mar. 17, 2001, entitled “Apparatus Used In Performing Femoral And Tibial Resection In Knee Surgery” and U.S. application Ser. No. 09/746,800, now U.S. Pat. No. 6,558,391, filed Dec. 23, 2000, entitled “Methods and Tools For Femoral Resection In Primary Knee Surgery”, the disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to methods and tools used in knee arthroplasty. More particularly, the invention relates to methods and tools used in knee surgery where artificial femoral and tibial components are installed.
[0003] Total knee arthroplasty involves the replacement of portions of the patellar, femur and tibia with artificial components. In particular, a proximal portion of the tibia and a distal portion of the femur are cut away (resected) and replaced with artificial components.
[0004] As used herein, when referring to bones or other body parts, the term “proximal” means closest to the heart and the term “distal” means more distant from the heart. When referring to tools and instruments, the term “proximal” means closest to the practitioner and the term “distal” means distant from the practitioner.
[0005] There are several types of knee prostheses known in the art. One type is sometimes referred to as a “resurfacing type”. In these prostheses, the articular surface of the distal femur and proximal tibia are “resurfaced” with respective metal and plastic condylar-type articular bearing components.
[0006] The femoral component is a metallic alloy construction (cobalt-chrome alloy or 6A14V titanium alloy) and provides medial and lateral condylar bearing surfaces of multi-radius design of similar shape and geometry as the natural distal femur or femoral-side of the knee joint.
[0007] One important aspect of these procedures is the correct resection of the distal femur and proximal tibia. These resections must provide planes which are correctly angled in order to properly accept the prosthetic components. In particular, the resection planes must be correctly located relative to three parameters: proximal-distal location, varus-valgus angle, and flexion-extension angle.
[0008] Moreover, following distal resection, the femur must be shaped with the aid of a cutting block. The cutting block must be correctly located relative to internal-external rotation, medial-lateral position, and anterior-posterior position.
[0009] Recently, various computerized systems have been introduced to aid the practitioner during different surgical procedures. A typical system is described in the attached Appendix.
[0010] These systems include multiple video cameras which are deployed above the surgical site and a plurality of dynamic reference frame (DRF) devices, also known as trackers, which are attached to body parts and surgical instruments. The trackers are generally LED devices which are visible to the cameras. Using software designed for a particular surgical procedure, a computer receiving input from the cameras guides the placement of surgical instruments.
[0011] The prior art instruments used for determining the correct planes for tibial and femoral resection in total knee arthroplasty are not well suited for use with computerized systems. The known tools utilize either intramedullary alignment or extra-medullary alignment and adjustment of the degrees of freedom simultaneously is difficult or impossible. Moreover, in order to be useful with computer aided navigation systems, trackers must be attached to the tools. Existing tools do not permit the attachment of trackers.
BRIEF SUMMARY OF THE INVENTION
[0012] It is therefore an object of the invention to provide methods and tools for performing femoral resection.
[0013] It is also an object of the invention to provide methods and tools for femoral resection which allow location of a cutting guide relative to six parameters.
[0014] It is another object of the invention to provide methods and tools for femoral resection which are infinitely adjustable.
[0015] It is still another object of the invention to provide methods and tools for femoral resection which are adapted to be used with computer aided navigation systems.
[0016] In accord with these objects which will be discussed in detail below, the tools according to a first embodiment of the present invention include an anchoring device for attachment to the femur and, a three-way alignment guide attachable to the anchoring device and adjustable relative to three parameters, a resection guide attachable to the alignment guide and equipped with couplings for trackers, an adjustable anterior-posterior sizer, a distal-proximal medial-lateral positioning guide, a medial-lateral cam lock, an anterior-posterior positioning guide, a femoral sizing block bushing, and femoral cutting guide.
[0017] The tools according to a second embodiment of the present invention include an anchoring device for attachment to the femur and, a six-way alignment guide attachable to the anchoring device and adjustable relative to six parameters, a pivotal 5-in-l positional alignment jig attachable to the alignment guide and equipped with couplings for trackers, a pair of mounting diodes attachable to the epicondylar region of the femur, and a 5-in-l cutting guide mountable on the diodes.
[0018] A first embodiment of the methods of the invention includes operating the computer aided navigation apparatus in the conventional manner including attaching one or more trackers to the bone to be resected; choosing a location for the anchoring device with or without guidance from the computer and installing the anchoring device; attaching the three-way alignment guide to the anchoring device; attaching a resection guide to the alignment guide; attaching one or two trackers to the resection guide; locating the resection guide with the aid of the alignment guide and the computer; fixing the resection guide to the bone with pins through the rotatable pin guides; and resecting the bone.
[0019] After the bone is resected, the adjustable anterior-posterior sizer is used to size the femur.
[0020] Next, the distal-proximal medial-lateral positioning guide, medial-lateral cam lock, anterior-posterior positioning guide, and femoral sizing block bushing are attached to the alignment guide.
[0021] The distal-proximal medial-lateral positioning guide, medial-lateral cam lock, and anterior-posterior positioning guide, when attached to the three-way guide, convert the three-way guide into a six-way guide. A tracker is preferably attached to the femoral sizing block bushing. The position of the bushing is adjusted in proximal-distal, varus-valgus, medial-lateral, and anterior-posterior directions. Two holes are drilled using the bushing as a guide. The femoral cutting guide is attached to the holes and the anterior and posterior cuts and chamfer cuts are made.
[0022] A second embodiment of the methods of the invention includes operating the computer aided navigation apparatus in the conventional manner including attaching one or more trackers to the bone to be resected; choosing a location for the anchoring device with or without guidance from the computer and installing the anchoring device; attaching the six-way alignment guide to the anchoring device; attaching the pivotal 5-in-i positional alignment jig to the alignment guide; attaching a tracker to the jig; positioning the jig in the varus-valgus, flexion-extension, internal-external rotation, distal-proximal, and anterior-posterior directions; drilling four holes in the epicondylar region using the jig as a guide; removing the jig, the alignment guide, and the anchoring device; installing a pair of diodes in the epicondylar region with screws in the holes; and mounting the 5-in-i cutting guide on the diodes.
[0023] The 5-in-1 cutting guide is then used to perform all of the femoral cuts as described in previously incorporated application Ser. No. 09/746,800.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a broken perspective view of the distal femur with an anchoring device according to the invention;
[0025] FIG. 2 is a side elevational view of the anchoring device installed in the distal femur;
[0026] FIG. 3 is a perspective view of the anchoring device installed in the distal femur with a three-way alignment guide according to the invention not yet attached to the anchoring device;
[0027] FIG. 4 is a view similar to FIG. 3 showing the alignment guide attached to the anchoring device;
[0028] FIG. 5 is a perspective view showing a first embodiment of a resection guide according to the invention not yet attached to the three-way alignment guide;
[0029] FIG. 6 is a perspective view showing a first embodiment of a resection guide according to the invention attached to the three-way alignment guide;
[0030] FIG. 7 is a side elevational view showing a first embodiment of a resection guide according to the invention attached to the three-way alignment guide;
[0031] FIGS. 8 and 8A are perspective views of an anterior-posterior sizer;
[0032] FIG. 9 is an exploded perspective view of the distal-proximal medial-lateral positioning guide, medial-lateral cam lock, anterior-posterior positioning guide, and femoral sizing block bushing;
[0033] FIG. 10 is a plan view of the distal-proximal medial-lateral positioning guide, medial-lateral cam lock, anterior-posterior positioning guide, and femoral sizing block bushing coupled to the alignment guide;
[0034] FIGS. 11 and 12 are perspective views of the distal-proximal medial-lateral positioning guide, medial-lateral cam lock, anterior-posterior positioning guide, and femoral sizing block bushing coupled to the alignment guide;
[0035] FIG. 13 is a side elevation view of the distal-proximal medial-lateral positioning guide, medial-lateral cam lock, anterior-posterior positioning guide, and femoral sizing block bushing coupled to the alignment guide;
[0036] FIGS. 14 and 15 are perspective views of a femoral cutting guide;
[0037] FIG. 16 is an exploded perspective view of a pivotal 5-in-l positional alignment jig and five-way alignment guide;
[0038] FIGS. 17-19 are perspective views of the pivotal 5-in-l positional alignment jig and five-way alignment guide coupled to the anchoring device;
[0039] FIG. 20 is a perspective view of a pair of diodes coupled to the epicondylar region of the femur; and
[0040] FIG. 21 is a perspective view of a 5-in-one cutting block mounted on the diodes.
BRIEF DESCRIPTION OF THE APPENDIX
[0041] The attached ten page Appendix describes the parts and assembly of a computer navigation system suitable for use with the invention.
DETAILED DESCRIPTION
[0042] Turning now to the Figures, the apparatus of the invention will be best understood by a description of the methods—of the invention with reference to the Figures. As shown in FIGS. 1 and 2 an anchoring device 10 is installed in the bone 1 in a region proximal to the lateral anterior cortex and within the incision. The location for the anchoring device may be chosen by eye or with the aid of the tracking/navigation software, with an emphasis on paralleling the anchoring device body to the sagittal plane. As shown in the Figures, the anchoring device 10 is a pin which is screwed into the bone. Other anchoring devices such as plates could be used, however.
[0043] With the anchoring device 10 in place, the alignment guide 12 is lowered on to it as shown in FIGS. 3-5 . As seen best in FIG. 5 , the alignment guide 12 has three cam locks 12 a , 12 b , 12 c . The cam lock 12 a allows the alignment guide to be adjusted according to flexion-extension angle relative to the anchoring device 10 . The cam lock 12 b allows the alignment guide to be adjusted according to varus-valgus angle relative to the anchoring device 10 . The cam lock 12 c opens the end of the alignment device to receive the resection guide 14 shown in FIGS. 5-7 and also allows for distal-proximal adjustment.
[0044] Referring now to FIGS. 5-7 , the resection guide 14 has a cutting guide surface 14 a , an attachment rod 14 b , a pair of connectors 14 c , 14 d for connecting trackers (not shown), a pair of rotatable pin guides 14 e , 14 f , and a pair of fail safe mounting bores 14 g , 14 h . The resection guide 14 is attached to the alignment guide 12 by opening cam lock 12 c and inserting the attachment rod 14 b into the alignment guide. It will be appreciated that the cam lock 12 c allows proximal-distal positioning of the resection guide 14 . After the resection guide 14 is attached to the alignment device 12 , a tracker is attached to the guide 14 .
[0045] With the tracker attached, the first cam lock 12 a is opened and the resection guide is moved in the varus-valgus plane until the navigation software indicates the proper alignment. The cam lock 12 a is then locked. Cam lock 12 b is unlocked and the resection guide is moved in the flexion-extension plane until the navigation software indicates the proper alignment. The cam lock 12 b is then locked
[0046] Lastly, the cam lock 12 c is opened and the resection guide is positioned in the proximal-distal plane until the navigation software indicates the proper alignment. The cam lock 12 c is then locked. With the resection guide properly located, it may be affixed to the bone with pins (not shown) via the rotatable pin guides 14 e , 14 f . The pin guides are rotatable so that the practitioner may choose the best site for inserting a pin. The next step in the procedure is to resect the distal end of the femur using the resection guide 14 .
[0047] Those skilled in the art will appreciate that if the˜anchor pin 10 is not substantially parallel to the sagittal plane, the steps may need to be repeated to tune out error introduced by the misaligned anchor pin. One possible solution is to install the pin with a drill having an attached tracker thereby allowing the navigation software to guide the placement of the pin.
[0048] Following distal femoral resection, the femur is sized using either of the following methods:
[0049] 1) Conventional sizing using either the Monogram or X-celerate sizing guides is performed. Surface digitization of the posterior condyles must be performed by the surgeon using the pointer by running the pointer tip over the posterior condylar bone and/or cartilage. The sizing guide is placed flush on the resected distal femur with the posterior skids against the posterior condyles. Either the sizing stylus or blade runner (or saw blade) is used to measure the most prominent aspect of the femoral lateral cortex. The femoral sizing block bushing can now be navigated.
[0050] An exemplary sizing guide 15 is shown in FIGS. 8 and 8 a . The adjustable A-P sizer 15 sets internal-external rotation and also allows an AP movement of +/−2 mm. This instrument is used after the femoral distal cut is performed. The feet 15 a , 15 b are inserted under the posterior condyles. The jig is allowed to move through six degrees either internally or externally as shown by the indicia between the letters “L” and “RI”.
[0051] A blade runner is introduced into one of the slots (labeled in 3, 5, 7, 9, 11, and 13 mm). The slot selected is the one that gives the required run-out anteriorly. If the surgeon is in between sizes, if he goes down a size, he will notch the femur, or if he moves up a size he will leave a gap. The jig allows the surgeon to obtain the optimal position.
[0052] Alternatively, software algorithms are used to size the femur. Surface digitization of the trochlear groove (patella track) and posterior condyles are performed by the surgeon using the pointer by running the pointer tip over the posterior condylar bone and/or cartilage. Digitized data is analyzed in the sagittal plane. Direct correlation to (or matching of) the correct femoral component is achieved via the software coding/algorithms. The surgeon will be able to visualize the matching on the operating room computer monitor (graphical interface). Sizing is complete using solely digitization methods. The femoral sizing block bushing can now be navigated.
[0053] Turning now to FIGS. 9-13 , after the distal femur is resected and sizing is completed, the appropriately sized femoral sizing block bushing 16 is attached to the alignment guide 12 using an anterior-posterior positioning guide 18 having a cam lock 18 a , a medial-lateral cam lock 20 , and a distal-proximal medial-lateral positioning guide 22 . The bushing 16 has a vertical shaft 16 a , a pair of drill guides 16 b , 16 c , and a tracker coupling 16 d . The vertical shaft 16 a is inserted into the anterior-posterior positioning guide 18 which is coupled to the medial-lateral cam lock 20 which is slidably coupled to the distal-proximal medial-lateral positioning guide 22 .
[0054] A tracker (not shown) is coupled to the coupling 16 d . Using the cam locks, the distal-proximal position is set by manually presenting the bushing 16 to the resected face of the femur. The internal-external rotation is navigated and the cam lock is locked on the positioning guide. The medial-lateral positioning of the bushing is navigated and locked using the medial-lateral cam lock 20 . Finally, anterior-posterior positioning is navigated and locked with the cam lock 18 a . Verification of the navigated position is done in conjunction with the screens on the computer. Once satisfied with the navigated position, two holes are drilled through the drill guides 16 b , 16 c . The complete anchoring mechanism is removed and the appropriate femoral cutting block is attached.
[0055] FIGS. 14 and 15 illustrate an exemplary cutting block 24 . The cutting block 24 has a pair of pins 24 a , 24 b which are impacted into the holes drilled with the bushing 16 (described above).
[0056] Additional fixation holes 24 c - 24 f are provided for optional fixation with pins. The cutting guide has four guiding surfaces: the anterior cut guiding surface 24 g , the posterior cut guiding surface 24 h , the anterior chamfer cut guiding surface 24 i , and the posterior chamfer cut guiding surface 24 j . After these four cuts are made, the cutting block is removed and the femur is near ready for accepting the prosthesis.
[0057] A second embodiment of the methods and tools of the invention is illustrated with reference to FIGS. 16 through 21 . The second embodiment utilized the same anchoring device 10 , alignment guide 12 , and the alignment devices 18 , 20 , 22 with a minor alteration. The anterior-posterior alignment device 18 ′ shown in the Figures has its cam lock 18 ′ a oriented in a slightly different position than the cam lock 18 a on the alignment device 18 . According to this embodiment, the devices 12 , 18 ′, 20 , and 22 are assembled to provide what amounts to a six-way alignment guide. Further according to this embodiment, a pivotal 5-in-l positional alignment jig is provided which includes the components 26 , 28 , and 30 . Component 26 is a T-bar having a vertical shaft 26 a , a lateral arm 26 b and a medial arm 26 c . Component 28 is a medial drilling guide arm having a mounting hole 28 a , a set screw 28 b , and drill guides 28 c . Component 30 is a lateral drilling guide arm having a mounting hole 30 a , a set screw 30 b , and drill guides 30 c.
[0058] After the femur is digitized as described above with reference to the first embodiment, the components are assembled as shown in FIGS. 17-19 . A tracker (not shown) is attached to one of the set screws 28 b , 30 b.
[0059] Using the various CAM locks, the medial and lateral drilling guides 28 , 30 are positioned in the following directions in the following order: varus-valgus, flexion-extension, internal-external rotation, distal-proximal, and anterior-posterior directions.
[0060] More particularly, the sequential locking of the guide begins with flexion-extension. The cam lock 12 b is opened and the jig is navigated until the recommended position is reached. Once reached, the flexion-extension cam lock 12 b is engaged.
[0061] Next, varus-valgus lock 12 a is opened and flexion-extension is navigated. The jig is navigated until the recommended position is reached. Once attained, the varus-valgus cam lock 12 a is engaged. Next, internal-external rotation is navigated.
[0062] The cam lock 12 c is opened and the jig is navigated until the recommended positions are reached.
[0063] Once attained, the internal-external rotation and distal-proximal translation are engaged. Next, anterior-posterior positioning is navigated. The cam lock 18 a is opened and the jig is navigated until the recommended position is reached. Once attained, the anterior-posterior cam lock 18 a is engaged. The medial-lateral positioning is not performed until the 5-in-l cutting guide is attached as described below with reference to FIG. 21 .
[0064] After the drilling guides are positioned, four holes are drilled into the epicondylar region using the drill guides 28 c , 30 c . All of the devices are then removed from the femur.
[0065] Referring now to FIG. 20 , a pair of diodes 32 , 34 are installed in the epicondylar region with screws (not shown), in the holes which were drilled in the previous step, using a screwdriver 36 .
[0066] Turning now to FIG. 21 , a 5-in-l cutting guide 38 is mounted on the diodes as described in previously incorporated application Ser. No. 09/746,800. Prior to fixing the cutting guide with pins, the medial-lateral position of the guide is fine tuned by the surgeon. The 5-in-l cutting block is then pinned in position and is used to perform all of the femoral cuts as described in previously incorporated application Ser. No. 09/746,800.
[0067] There have been described and illustrated herein methods and tools for resection of the distal femur. While particular embodiments of the invention have been described, it is not intended that the invention be limited thereto, as it is intended that the invention be as broad in scope as the art will allow and that the specification be read likewise. For example, the first two positioning steps may be reversed in sequence, provided that the navigation software is suitably modified. Moreover, the clamps on the alignment guides need not be cam locks, but could be other types of clamps. Although the apparatus has been described as separate pieces (e.g. the anchor, the alignment guide, and the resection guide), it could be two pieces or a single piece. In general, the methods and tools of the invention could be used with other joints other than the knee. It is believed that the methods and tools could be used in arthroplasty of the hip, shoulder, elbow, etc.
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Tools for resecting the femur include an anchoring device, a three-way alignment guide and a six way alignment guide attachable to the anchoring device, a resection guide attachable to the three-way alignment guide and equipped with couplings for trackers, an A-P sizer, a femoral sizing block bushing attachable to the six-way alignment guide, a 4-in-i femoral cutting block, a 5-in-i positional alignment guide attachable to the six-way alignment guide, a pair of diodes, and a 5-in-one cutting block. Methods of utilizing the apparatus are also disclosed.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to an intervertebral spacer and method for spacing and fusing adjacent vertebrae and, more particularly, to a porous, strong, intervertebral spacer formed of a biologically inert material.
2. Description of the Prior Art
Techniques and devices for fusing two or more vertebrae of the spine together are well known. Such techniques are commonly performed to correct problems, such as chronic back pain, which result from degenerated intervertebral discs. One technique for fusing together two or more vertebrae of the lumbar spine includes excising a portion of the disc extending between adjacent vertebrae and grafting one or more portions of bone of a desired shape, known as an intervertebral spacer, between the adjacent vertebrae. The intervertebral spacer may be inserted by either an anterior or posterior approach to the spinal column depending on a number of factors, including the number of vertebrae to be fused and past operative procedures. Upon healing, the vertebrae are desirably fused together through the intervertebral spacer.
Conventionally, intervertebral spacers have been autogenic bone harvested from other areas of the body, such as the pelvis, allogenic bone taken from cadavers or xenogenic bone, such as bovine bone sections. However, the use of bone grafts can add complications to the fusion procedure. For example, when using an autogenic bone graft, a second incision must be made in the patient to harvest the additional bone to be used in the graft, thus increasing the pain and blood loss to the patient. When allogenic or xenogenic bone grafts are used there is a potential for the transmission of disease from the cadaver or other graft source to the patient.
The use of non-biological implants, such as carbon fiber spacers, also has been attempted in the past, but these spacers tend to lack sufficient porosity and tissue ingrowth characteristics to function adequately.
It would be desirable to provide a non-biological spacer which is non-reactive in the body and which has the strength and tissue ingrowth characteristics of a bone graft spacer.
SUMMARY OF THE INVENTION
The present invention provides a porous intervertebral spacer which can be used in the same manner as a bone graft spacer to fuse vertebrae together. The inventive spacer preferably is composed biologically inert strands, or a mixture of such strands and biologically inert beads sintered in a mold of a desired shape and size. The spacer is made of metals such as titanium, and thus is non-biologically reactive and provides for tissue ingrowth to facilitate fusion with adjacent vertebrae.
In accordance with one aspect of the invention, a porous intervertebral spacer is formed in a variety of shapes such as a prism (for example, a rectangular prism), a cylinder, and a plate. In each instance, the spacer is made of a plurality of fused, tortuous strands or a mixture of tortuous strands and beads of a biologically inert material such as titanium or a titanium alloy.
In accordance with another aspect of the invention a method of fusing adjacent vertebrae of the spine includes the steps of excising a portion of an intervertebral disc separating adjacent vertebra and portions of the adjacent vertebrae to define a graft bed, and inserting into the graft bed at least one porous intervertebral spacer formed from a plurality of fused, tortuous strands or a mixture of tortuous strands and beads of a biologically inert material such as titanium or a titanium alloy.
In general, the invention comprises the foregoing and other features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail a certain illustrated embodiment of the invention, this being indicative, however, of but one of the various ways in which the principles of the invention may be employed.
BRIEF DESCRIPTION OF THE DRAWINGS
In the annexed drawings:
FIG. 1 is a perspective view of an intervertebral spacer similar to the spacer of the present invention, the spacer being in the form of a rectangular prism;
FIG. 2 is an elevational view of the anterior of a portion of the lumbar spine and sacrum illustrating a graft bed;
FIG. 3 is a view similar to FIG. 2 showing spacers according to the invention implanted in the graft bed;
FIG. 4 is a side elevational view of two representative lumbar vertebrae illustrating the location of a posterior-formed graft bed;
FIG. 5 is an elevational view of the posterior of representative lumbar vertebrae illustrating the locations of separate posteriorly formed graft beds;
FIG. 6 is a view similar to FIG. 5 showing two spacers according to the invention implanted in the graft beds;
FIG. 7 is an enlarged view of the surface of the spacer of FIG. 1;
FIG. 8 is a view similar to FIG. 7 showing the surface enlarged to an even greater extent;
FIG. 9A is a perspective view similar to FIG. 1, showing a spacer provided with a plurality of parallel apertures-opening through the top and bottom faces of the spacer;
FIG. 9B is a perspective view of an intervertebral spacer in accordance with the invention, the spacer being in the form of a cylinder and including a plurality of apertures that are disposed parallel to the end faces of the cylinder;
FIG. 9C is a view similar to FIG. 9A, showing the use of external teeth, or ribs;
FIG. 9D is a view similar to FIG. 9B in which a large cylindrical opening extends longitudinally through the center of the spacer;
FIG. 9E is a view similar to FIG. 9A in which the top and bottom faces of the spacer are rounded;
FIG. 9F is a perspective view of a intervertebral spacer according to the invention, the spacer being in the form of a hexagonal prism with apertures opening through the top and bottom faces;
FIG. 9G is a view similar to FIG. 9F in which the spacer is in the form of an octagonal prism with apertures opening through the top and bottom faces;
FIG. 9H is a view similar to FIG. 9F in which the end faces are rhombuses;
FIG. 9I is a perspective view of a plate-like intervertebral spacer which, when viewed from above, is generally C-shaped;
FIG. 9J is a-view similar to FIG. 9I in which ribs have been added to the upper and lower faces of the spacer;
FIG. 9K is a view similar to FIG. 9I showing an elliptical spacer with an elliptical opening at its center;
FIG. 9L is a view similar to FIG. 9K in which ribs have been added to the upper and lower faces of the spacer;
FIG. 9M is a view similar to FIG. 9I showing a kidney-shaped spacer; and
FIG. 9N is a view similar to FIG. 9M in which ribs have been added to the upper and lower faces of the spacer.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawings and initially to FIGS. 1, 7 , and 8 , there is shown an intervertebral spacer 10 similar to the present invention. The embodiment of FIG. 1 is disclosed and claimed in U.S. Pat. No. 5,961,554, the disclosure of which is incorporated herein by reference.
The spacer 10 is in the form of a porous biologically inert block in the form of a rectangular prism. The corners and edges of the spacer 10 may be formed with a small radius if desired. One or more such rectangular, block-shaped spacers 10 are sized to fit within an opening or graft bed formed between adjacent vertebrae by the surgical excision of a portion of the intervertebral disc and confronting portions of the adjacent vertebral bodies. The particular size of the spacer 10 will be determined by the particular vertebrae to be fused, and condition of the vertebrae. Advantageously, because the spacers are not made of a biological material, they are easily stored and can be manufactured in a variety of shapes and sizes to accommodate anticipated situations. A typical spacer 10 for fusing vertebrae of the lumbar spine may be from 10 to 13 millimeters in width, 12 to 18 millimeters in height, and 25 to 30 millimeters in length.
It will be appreciated that while the specific example of the intervertebral spacer described herein is with reference to a spacer for fusing vertebrae of the lumbar spine together or to the sacrum, the invention applies also to spacers for fusing vertebrae of the cervical or thoracic spine as well. The particular shape of the spacer is also a function of the application. While a generally rectangular spacer is well suited to fusing lumbar vertebrae, in other instances other shapes for the spacer, such as cylindrical, may be desirable. Moreover, it will be recognized that the spacers of the invention may also be used in other areas of the body to fuse bone together where necessary.
The spacer 10 is preferably composed of biologically inert spheres or beads 94 having a diameter such as to yield, when fused, a spacer with the fused beads 94 occupying a range of generally 40 to 70 percent of the volume of the spacer. This density provides a spacer 10 which is sufficiently porous throughout to allow for the flow of bodily fluids through the spacer and to promote tissue ingrowth and bony fusion with adjacent vertebrae. The beads 94 also result in porous surfaces 12 over the spacer 10 which when implanted develop a high friction interface with the contacting vertebral bodies to facilitate maintaining the spacer in place. The beads 94 are preferably composed of titanium or a titanium alloy (such as Ti- 6 AI-4V) which is nonreactive within the body. Since the early 1970's, titanium and titanium alloys have been approved by the United States Food and Drug Administration for use in knee, shoulder, and hip implants to promote bone ingrowth. Other suitable materials include cobaltchromium alloys, tantalum, tantalum alloys, niobium, niobium alloys, and stainless steel, or any other metal having adequate strength and biocompatibility properties.
It has been found that beads of a certain size range are preferred. Suitable small beads will have a mesh size of −45 +60 (0.009 inch to 0.011 inch). Suitable medium beads will have a mesh size of −25 +30 (0.016 inch to 0.027 inch). Suitable large beads will have a mesh size of −18 +30 (0.032 to 0.046 inch). The size of the beads determines the porosity of the finished spacer 10 . The larger the beads, the greater the porosity. In certain applications, it may be desirable to mix beads of various sizes to obtain a finished spacer 10 having a variable porosity.
The invention involves the discovery that it is possible to intermix strips, or strands, of wire mesh with beads to form a spacer 10 having variable qualities of strength and porosity. In general, the use of wire mesh results in a stronger, less porous spacer 10 . It also is possible to form the spacer 10 entirely of wire mesh. Such mesh presently is used as a porous coating for knee, shoulder, and hip implants. Such mesh sometimes is referred to a spaghetti mesh, and is commercially available from the Zimmer Company of Warsaw, Ind. The types of metals suitable for the strands of wire mesh and the beads are the same as those set forth above for the beads 94 . Reference is made to U.S. Pat. No. 3,906,550; 4,693,721; and 5,665,119, the disclosures of which are incorporated herein by reference, for a discussion of the use of metal fiber as a porous bone structure material.
One suitable method of fusing titanium beads, titanium mesh, or a mixture of titanium beads and mesh to form the spacer 10 includes placing the beads and/or strands into a cavity within a substantially purified graphite mold. The mold is preferably a three piece mold forming a cavity of the finished dimensions of the spacer 10 . The mold is then heated to a high temperature, for example, 2000 degrees F. or higher until the sintering is complete, around 24 hours. Other conventional methods for fusing titanium strands or beads which provide a sufficiently strong spacer 10 also may be acceptable. When titanium spaghetti mesh is used to form the spacer 10 , the strands of mesh are placed in the mold in a tangled, tortuous mass. Sintering produces strong inter-strand bonds with variably sized openings to form a spacer 10 of suitable strength and porosity.
The procedure for fusing two or more vertebrae together using the spacer 10 of the invention is substantially the same as the procedure for fusing vertebrae using a bone graft, but without many of the complications due to obtaining a suitable bone graft and the possibility of transmitting disease from the bone graft donor. One anterior procedure for implanting a bone graft to fuse vertebra of the lumbar spine is discussed in Collis et al., “Anterior Total Disc Replacement:, A Modified Anterior Lumbar Interbody Fusion,” Lumbar Interbody Fusion, ed. Robert Watkins, Chapter 13, pp. 149-152, Aspen Publications (1989), the disclosure of which is incorporated herein by reference.
Referring to FIGS. 2 and 3, there is shown an anterior elevation view of the lumbar spine 14 including the fourth and fifth lumbar vertebrae 16 , 18 , respectively, and the sacrum 20 with the sacral vessels 22 ligated and both iliac vessels 24 retracted outwardly to expose the vertebral disc 26 between the fifth lumbar vertebra 18 and the sacrum 20 . As an example, to fuse the fifth lumbar vertebra 18 to the sacrum 20 , using an anterior approach, a graft bed 28 is prepared by surgically exposing the affected area and excising portions of the vertebral body of the vertebra 18 and the sacrum 20 and the section of the disc 24 located therebetween, as shown in FIG. 2 . An appropriate number of spacers 10 , in this example, three, are then implanted into the graft bed 28 . Over time bony tissue ingrowth will desirably fuse the vertebral bodies of the vertebra 18 and the sacrum 20 to the spacers 10 and thus fuse the vertebra to the sacrum through the spacers. The number of spacers 10 employed will be a function of a number of factors, including the particular vertebrae to be fused and the deterioration of the vertebral disc and of the vertebral bodies themselves.
The intervertebral spacers 10 may also be implanted through known posterior approaches. In a typical procedure using a posterior approach in which two spacers are implanted, such as is shown in FIGS. 4 through 6 which represent side and rear elevations of, two representative lumbar vertebrae 30 , 32 , the posterior portion of the subject area of the lumbar spine is surgically exposed. Graft beds 34 are then formed by excising the required portions of adjacent vertebral bodies 36 , 38 of the vertebrae 30 , 32 , respectively, and a section of the disc located therebetween. The graft beds 34 may be formed using a cutting tool 40 , such as is shown in FIG. 4 (FIG. 4 omits the Canda Equina and the disc for clarity), wherein portions of the lamina 41 and/or spinous process 42 of one or both of the vertebrae are removed to open a passage 44 through which the tool may be inserted to reach the vertebral bodies. To implant the spacers 10 once the graft beds 34 have been formed, the Canda Equina and protective dura 46 are first retracted to one side to expose a graft bed and a spacer is inserted into the exposed graft bed (see FIG. 5 ), and then the Canda Equina and dura are retracted to the other side to insert a spacer into the exposed other graft bed.
Referring now to FIGS. 9A-9N, the spacer according to the invention is shown in a variety of configurations. In all of these configurations, the spacer is formed by sintering titanium or titanium alloy beads or spaghetti mesh within a suitably configured mold. In particular, FIG. 9A shows the spacer 10 provided with a plurality of parallel, equidistantly spaced apertures 46 . The apertures 46 open through the top and bottom faces of the spacer 10 . It also is possible to provide a longitudinally extending opening (not shown) that opens through the end faces of the spacer 10 .
The spacer 10 can be provided in various sizes. A typical size is 10 mm wide, 27 mm long, and a variable height of 8, 10, 12, 14, 16 or 18 mm. The spacer 10 can be provided in shorter lengths of 24 mm, or longer lengths of 30 mm. For those spacers 10 having a width of 10 mm, the apertures 46 should have a diameter of about 0.1875 inch.
The spacer 10 also can be provided in the different widths, for example, 13-40 mm. With a width of 13 mm, variable lengths of 24, 27 or 30 can be provided. The height also can be selected among 8, 10, 12, 14, 16 or 18 mm. For spacers 10 having a width of 13 mm, the apertures 46 should have a diameter of 0.2188 inch.
Referring now to FIG. 9B, a spacer 50 in the form of a cylinder is shown. The spacer 50 is provided in various diameters and lengths, for example, 10 mm, 12 mm, 14 mm and 16 mm diameter, and lengths of 24, 27 and 30 mm. As with the spacer 10 , three equidistantly spaced apertures 46 are provided for the spacer 50 . For spacers 50 having diameters of 10 or 12 mm, the apertures 46 have a diameter of about 0.1875 inch, while for spacers 50 having a diameter of 14 or 16 mm, the apertures 46 have a diameter of about 0.2188 inch.
Referring now to FIG. 9C, the spacer 10 is provided with laterally extending teeth or ribs 52 . In cross section, the ribs 52 are triangular with a vertex angle of 60 degrees and a height of 2 mm. The ribs 52 prevent undesired movement of the spacer 10 within the patient after the spacer 10 has been implanted in the graft bed 28 .
Referring to FIG. 9D, the spacer 50 is shown with two spaced-apart apertures 46 . The spacer 50 also is provided with a longitudinally extending aperture 54 that opens through the end faces of the spacer 50 . The diameter of the aperture 54 is selected such that the wall thickness of the spacer 50 is approximately 3 mm.
Referring now to FIG. 9E, the spacer 56 is similar to the spacer 10 , but includes flat, parallel end faces and sidewalls, and rounded top and bottom faces 58 . As with the spacer 10 , a plurality of apertures 46 are provided for the spacer 56 . The dimensions for the width, length, and height of the spacer 56 are the same as those described previously for the spacer 10 . The radius for the top and bottom faces 58 should be approximately 9 mm.
Referring now to FIGS. 9F, 9 G and 9 H, spacers 60 , 62 and 64 are illustrated. The spacer 60 is a hexagonal prism, the spacer 62 is an octagonal prism, and the spacer 64 is a, rhomboidal prism. The spacers 60 , 62 , as with the spacer 10 , are provided with a plurality of parallel, equidistantly spaced apertures 46 . If desired, the spacers 60 , 62 and 64 could be provided with longitudinally extending openings such as the opening 54 included as part of the spacer 50 . In general, the spacer according to the invention can be provided in a variety of geometric configurations. Virtually any polyhedron prism will provide satisfactory results.
Referring to FIGS. 9I-9N, a variety of plate-like spacers are shown. The spacers are provided in a variety of lengths, widths, and depths to fit all male and female vertebral bodies. In FIG. 9I, a spacer 66 includes flat, parallel upper and lower faces 68 , 70 with a rounded exterior surface 72 and a cut-out portion 74 . The spacer 66 generally is C-shaped. In FIG. 9J, the spacer 66 is provided with a plurality of ribs 76 that are similar in size and shape to the ribs 52 and which perform the same function.
In FIG. 9K, a spacer 78 includes an elliptical body portion 80 with an elliptical opening 82 at its center. In FIG. 9L, the spacer 78 is provided with ribs 84 of the same size and shape as the ribs 52 .
Referring to 9 M, a spacer 86 includes a kidney-shaped body portion 88 having a small cut-out portion 90 . In FIG. 9N the spacer 86 is provided with ribs 92 that are the same size and shape as the ribs 52 .
It is expected that the spacers 66 , 78 , 86 will be provided in sizes large enough to perform the function of two or three spacers 10 or 50 . It is expected that a single, large graft bed 28 will be formed such that the spacer 68 , 78 , 86 will fill the graft bed 28 entirely.
Although the invention has been shown and described with respect to a certain preferred embodiment, it is apparent that equivalent alterations and modifications will occur to others skilled in the art upon reading and understanding this specification. The present invention includes all such equivalent alterations and modifications and is limited only by the scope of the following claims.
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A porous intervertebral spacer comprises a plurality of strands of fused, tortuous wire of a biologically inert material, the porosity of the spacer being sufficient to facilitate tissue ingrowth and bony fusion. The spacer also can comprise a mixture of such strands and biologically inert beads. A method of fusing adjacent vertebrae of the spine includes the steps of excising a portion of an intervertebral disc separating adjacent vertebrae and portions of the adjacent vertebrae to define a graft bed, and inserting into the graft bed at least one porous intervertebral spacer according to the invention.
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CROSS REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-238119, filed on Sep. 1, 2006, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, and particularly relates to a semiconductor device incorporating a non-volatile semiconductor memory (such as a ferroelectric memory).
2. Description of the Related Art
Generally, in a semiconductor device incorporating a ferroelectric memory, a voltage supplied via an external power supply pin or a voltage obtained by boosting/stepping down the voltage supplied via the external power supply pin is used as a power supply voltage of the ferroelectric memory. Among the semiconductor devices each incorporating the ferroelectric memory, in an IC card (Integrated Circuit Card), a RFID (Radio Frequency Identification), and so on, a stability capacitance (constituted of a ferroelectric capacitance) is often connected between a power supply pin of the ferroelectric memory and a ground line in order to stabilize the power supply voltage of the ferroelectric memory.
The ferroelectric memory has a failure mode regarding data retention called a retention failure, and hence it needs to be guaranteed to retain write data for a predetermined time or more in a power-on state (state in which the power supply voltage is being supplied) and retain write data for a predetermined time or more in a power-off state (state in which the power supply voltage is not being supplied).
Therefore, in a test process of the semiconductor device incorporating the ferroelectric memory, a screening test for a retention failure when the ferroelectric memory is powered off (power-off retention test) is performed in the following steps. First, predetermined data is written into the ferroelectric memory. Subsequently, the voltage supply from an external testing apparatus to an external power supply pin of the semiconductor device is stopped to stop the supply of the power supply voltage to the ferroelectric memory. Then, in a predetermined time after the supply of the power supply voltage to the ferroelectric memory is stopped, the voltage supply from the external testing apparatus to the external power supply pin of the semiconductor device is resumed to resume the supply of the power supply voltage to the ferroelectric memory. Thereafter, data is read from the ferroelectric memory, and the presence or absence of the retention failure is determined by comparing the read data and the predetermined data.
Moreover, Japanese Unexamined Patent Application Publication No. 2000-299000 discloses a non-volatile semiconductor memory which is configured to be able to supply a voltage obtained by stepping down a power supply voltage to a memory block in addition to the power supply voltage and to ensure reliable data retention even when the memory block is constituted of a ferroelectric memory. Japanese Unexamined Patent Application Publication No. 2004-61114 discloses a self-diagnosis test circuit which can realize a reduction in test time, an improvement in yield, and an increase in test coverage in a test of a semiconductor device.
In the conventional semiconductor device, to stop the supply of the power supply voltage to the ferroelectric memory in the power-off retention test of the ferroelectric memory, the supply of the voltage from the external testing apparatus to the external power supply pin of the semiconductor device needs to be stopped. Therefore, during the power-off retention test of the ferroelectric memory, the supply of the power supply voltage to functional blocks except the ferroelectric memory is also stopped. This causes a problem that during the power-off retention test of the ferroelectric memory, the functional blocks except the memory block cannot be tested, thereby increasing a test time of the semiconductor device.
Further, with the stability capacitance, even if the voltage supply from the external testing apparatus to the external power supply pin of the semiconductor device is stopped to stop the supply of the power supply voltage to the ferroelectric memory in the power-off retention test thereof, the voltage is supplied to the ferroelectric memory only for a time taken for discharging an electric charge accumulated in the stability capacitance. Hence, whit the stability capacitance, it is necessary to lengthen the time for stopping of the voltage supply from the external testing apparatus to the external power supply pin of the semiconductor device by the waiting time for the completion of discharge of the electric charge accumulated in the stability capacitance, which causes a problem of an increase in the test time of the semiconductor device.
SUMMARY OF THE INVENTION
An object of the present invention is to reduce a test time of a semiconductor device incorporating a non-volatile semiconductor memory.
In a first aspect of the present invention, a semiconductor device includes plural functional blocks, a voltage supply circuit, a cut-off circuit, and a self test circuit. The plural functional blocks include a non-volatile memory block. For example, the memory block is constituted of a ferroelectric memory. The voltage supply circuit supplies a power supply voltage to the functional blocks. The cut-off circuit cuts off the supply of the power supply voltage from the voltage supply circuit to the memory block. The self test circuit performs tests of the functional blocks. In a data retention test of the memory block, the self test circuit instructs the cut-off circuit to start an operation after writing predetermined data into the memory block, and instructs the cut-off circuit to stop the operation to check retention of the predetermined data in the memory block in a predetermined time after the instruction to the cut-off circuit to start the operation.
For example, the semiconductor device further includes a stability capacitance and a discharge circuit. The stability capacitance is connected between a power supply pin of the memory block and a ground line. For example, the stability capacitance is constituted of a ferroelectric capacitance. The discharge circuit discharges an electric charge accumulated in the stability capacitance. In the data retention test of the memory block, the self test circuit instructs the discharge circuit to start an operation along with the instruction to the cut-off circuit to start the operation, and instructs the discharge circuit to stop the operation along with the instruction to the cut-off circuit to stop the operation.
In the above first aspect, in the data retention test of the memory block by the self test circuit, the supply of the power supply voltage from the voltage supply circuit to the memory block is cut off, but the supply of the power supply voltage from the voltage supply circuit to the functional blocks except the memory block is not cut off. Hence, the self test circuit can perform tests of the functional blocks except the memory block in parallel with performing the data retention test of the memory block.
Further, in the data retention test of the memory block by the self test circuit, the electric charge accumulated in the stability capacitance is discharged along with cut off of the supply of the power supply voltage from the voltage supply circuit to the memory block. Therefore, in the data retention test of the memory block by the self test circuit, the time taken for cutting off the supply of the power supply voltage from the power supply circuit to the memory block does not need to include waiting time for the completion of discharge of the electric charge accumulated in the stability capacitance. In the first aspect described above, the test time of the semiconductor device can be greatly reduced, which contributes to cost reduction.
In a preferred example of the first aspect of the present invention, the cut-off circuit includes a voltage supply control switch. The voltage supply control switch is connected between a power supply line and the power supply pin of the memory block, the power supply line being supplied with the power supply voltage by the voltage supply circuit. The voltage supply control switch is turned off in response to the instruction from the self test circuit to the cut-off circuit to start the operation, and turned on in response to the instruction from the self test circuit to the cut-off circuit to stop the operation. Consequently, the cut-off circuit which cuts off the supply of the power supply voltage from the voltage supply circuit to the memory block can be easily constituted.
In a preferred example of the first aspect of the present invention, the discharge circuit includes a discharge control switch. The discharge control switch is connected between the power supply pin of the memory block and the ground line. The discharge control switch is turned on in response to the instruction from the self test circuit to the discharge circuit to start the operation, and turned off in response to the instruction from the self test circuit to the discharge circuit to stop the operation. Consequently, the discharge circuit which discharges the electric charge accumulated in the stability capacitance can be easily constituted.
In a second aspect of the present invention, a semiconductor device includes plural functional blocks, a voltage supply circuit, a cut-off circuit, and a self test circuit. The plural functional blocks include a non-volatile memory block. The voltage supply circuit supplies a first power supply voltage to the memory block and supplies a second power supply voltage to at least one of the functional blocks except the memory block. For example, the voltage supply circuit includes first and second voltage generating circuits. The first voltage generating circuit generates the first power supply voltage using an external input voltage, and the second voltage generating circuit generates the second power supply voltage by stepping down the first power supply voltage. Alternatively, the first voltage generating circuit generates the second power supply voltage using the external input voltage, and the second voltage generating circuit generates the first power supply voltage by boosting the second power supply voltage. The cut-off circuit cuts off the supply of the first power supply voltage from the voltage supply circuit to the memory block. The self test circuit performs tests of the functional blocks. In a data retention test of the memory block, the self test circuit instructs the cut-off circuit to start an operation after writing predetermined data into the memory block, and instructs the cut-off circuit to stop the operation to check retention of the predetermined data in the memory block in a predetermined time after the instruction to the cut-off circuit to start the operation.
For example, the semiconductor device further includes a stability capacitance and a discharge circuit. The stability capacitance is connected between a power supply pin of the memory block and a ground line. The discharge circuit discharges an electric charge accumulated in the stability capacitance. In the data retention test of the memory block, the self test circuit instructs the discharge circuit to start an operation along with the instruction to the cut-off circuit to start the operation, and instructs the discharge circuit to stop the operation along with the instruction to the cut-off circuit to stop the operation.
The above second aspect can obtain the same effect as the above first aspect, although in the second aspect an operation voltage of the memory block is different from an operation voltage of at least one of the functional blocks except the memory block, and the semiconductor device has two separate internal power supply systems; one with the first power supply voltage and the other with the second power supply voltage.
BRIEF DESCRIPTION OF THE DRAWINGS
The nature, principle, and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designated by identical reference numbers, in which:
FIG. 1 is a block diagram showing a first embodiment of the present invention;
FIG. 2 is a flowchart showing the operation of a BIST circuit in the first embodiment;
FIG. 3 is a block diagram showing a second embodiment of the present invention; and
FIG. 4 is a block diagram showing a third embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Embodiments of the present invention will be described below using the drawings.
FIG. 1 shows a first embodiment of the present invention. A semiconductor device 10 of the first embodiment includes a power supply circuit 11 , a logic block 13 , a memory block 14 , a BIST (Built-In Self Test) circuit 15 , a voltage supply control switch 16 , a stability capacitance 17 , and a discharge control switch 18 . The power supply circuit 11 generates a power supply voltage VDD 1 using an external input voltage VDD (voltage supplied from outside via a power supply pin PE) and supplies the power supply voltage VDD 1 to a power supply line PL 1 .
The logic block 13 embodies a processor function, a timer function, a communication interface function, and so on. The logic block 13 can perform a read access and a write access to the memory block 14 . The memory block 14 is constituted of a ferroelectric memory including plural memory cells (each constituted of a ferroelectric capacitance and a transfer transistor) arranged in a matrix. In the memory block 14 , the ferroelectric capacitance and the transfer transistor which constitute the memory cell are connected in series between a plate line and a bit line, and a gate of the transfer transistor is connected to a word line.
The BIST circuit 15 performs various tests of the logic block 13 and the memory block 14 (an operation test of the logic block 13 , an operation test of the memory block 14 , a power-on retention test/power-off retention test of the memory block 14 , and so on). The BIST circuit 15 performs on/off control of the voltage supply control switch 16 and the discharge control switch 18 when performing the power-off retention test of the memory block 14 . Details of this operation will be described later using FIG. 2 .
The voltage supply control switch 16 is provided to cut off the supply of the power supply voltage VDD 1 from the power supply circuit 11 to a power supply pin PM of the memory block 14 and connected between the power supply line PL 1 and a power supply line PL 1 a (power supply pin PM of the memory block 14 ). The power supply control switch 16 is turned on/off in response to an instruction of the BIST circuit 15 . The stability capacitance 17 is provided to stabilize a voltage (voltage of the power supply line PL 1 a ) supplied to the power supply pin PM of the memory block 14 and connected between the power supply line PL 1 a (power supply pin PM of the memory block 14 ) and a ground line GL. The stability capacitance 17 is constituted of a ferroelectric capacitance. The discharge control switch 18 is provided to discharge an electric charge accumulated in the stability capacitance 17 and connected between the power supply line PL 1 a (power supply pin PM of the memory block 14 ) and the ground line GL. The discharge control switch 18 is turned on/off in response to an instruction of the BIST circuit 15 .
FIG. 2 shows the operation of the BIST circuit in the first embodiment. When performing the power-off retention test of the memory block 14 , the BIST circuit 15 operates as follows. First, the BIST circuit 15 writes predetermined data into the memory block 14 (step S 11 ). Then, the BIST circuit 15 gives an instruction to turn off the voltage supply control switch 16 (step S 12 ). Consequently, the voltage supply control switch 16 is turned off, the power supply line PL 1 and the power supply line PL 1 a are disconnected, and the supply of the power supply voltage VDD 1 from the power supply circuit 11 to the memory block 14 is cut off. Subsequently, the BIST circuit 15 gives an instruction to turn on the discharge control switch 18 (step S 13 ). Consequently, the discharge control switch 18 is turned on, and the electric charge accumulated in the stability capacitance 17 is immediately discharged to the ground line GL.
Then, in a predetermined time T after the instruction to turn on the discharge control switch 18 is given, the BIST circuit 15 gives an instruction to turn off the discharge control switch 18 (step S 14 ). Hence, the discharge control switch 18 is turned off. Subsequently, the BIST circuit 15 gives an instruction to turn on the voltage supply control switch 16 (step S 15 ). Consequently, the voltage supply control switch 16 is turned on, the power supply line PL 1 and the power supply line PL 1 a are connected, and the supply of the power supply voltage VDD 1 from the power supply circuit 11 to the memory block 14 is resumed. After this, the BIST circuit 15 checks retention of the predetermined data in the memory block 14 (step S 16 ). To put it in more detail, after reading data from the memory block 14 , the BIST circuit 15 determines the presence or absence of a retention failure by a comparison between the read data and the predetermined data (data written into the memory block 14 in step S 11 ).
In the above first embodiment, when the BIST circuit 15 performs the power-off retention test of the memory block 14 , the supply of the power supply voltage VDD 1 from the power supply circuit 11 to the memory block 14 is cut off, but the supply of the power supply voltage VDD 1 from the power supply circuit 11 to the logic block 13 is not cut off. Hence, the BIST circuit 15 can perform an operation test of the logic block 13 in parallel with performing the power-off retention test of the memory block 14 .
Further, when the BIST circuit 15 performs the power-off retention test of the memory block 14 , the supply of the power supply voltage VDD 1 from the power supply circuit 11 to the memory block 14 is cut off, and along with this, the electric charge accumulated in the stability capacitance 17 is discharged. Therefore, when the BIST circuit 15 performs the power-off retention test of the memory block 14 , the time (predetermined time T) taken for cutting off the supply of the power supply voltage VDD 1 from the power supply circuit 11 to the memory block 14 does not need to include waiting time for the completion of discharge of the electric charge accumulated in the stability capacitance 17 . In the first embodiment described above, the test time of the semiconductor device 10 can be greatly reduced, which contributes to cost reduction.
FIG. 3 shows a second embodiment of the present invention. The second embodiment ( FIG. 3 ) will be described below, but the same reference symbols as used in the first embodiment will be used to designate the same elements as described in the first embodiment ( FIG. 1 ), and a detailed description thereof will be omitted. A semiconductor device 20 of the second embodiment is the same as the semiconductor device 10 of the first embodiment except that it includes a step-down circuit 22 and includes a logic block 23 and a BIST circuit 25 instead of the logic block 13 and the BIST circuit 15 .
The step-down circuit 22 steps down the power supply voltage VDD 1 (voltage of the power supply line PL 1 ) to generate a power supply voltage VDD 2 and supplies the power supply voltage VDD 2 to a power supply line PL 2 . The logic block 23 and the BIST circuit 25 are the same as the logic block 13 and the BIST circuit 15 except that they receive the power supply voltage VDD 2 supplied to the power supply line PL 2 instead of the power supply voltage VDD 1 supplied to the power supply line PL 1 (except that operation voltages are different).
In the above second embodiment, the operation voltage of the logic block 23 is lower than the operation voltage of the memory block 14 , and an internal power supply system of the semiconductor device 20 is separated into two systems: a power supply system for the memory block 14 (power supply system with the power supply voltage VDD 1 generated by the power supply circuit 11 ) and a power supply system for the logic block 23 (power supply system with the power supply voltage VDD 2 generated by the step-down circuit 22 ), and also in such a case, the same effect as in the above first embodiment can be obtained.
FIG. 4 shows a third embodiment of the present invention. The third embodiment ( FIG. 4 ) will be described below, but the same reference symbols as used in the first and second embodiments will be used to designate the same elements as described in the first and second embodiments ( FIG. 1 and FIG. 3 ), and a detailed description thereof will be omitted. A semiconductor device 30 of the third embodiment is the same as the semiconductor device 20 of the second embodiment except that it includes a power supply circuit 31 and a boost circuit 32 instead of the power supply circuit 11 and the step-down circuit 22 .
The power supply circuit 31 generates the power supply voltage VDD 2 using the external input voltage VDD (voltage supplied from outside via the power supply pin PE) and supplies the power supply voltage VDD 2 to the power supply line PL 2 . The boost circuit 32 boosts the power supply voltage VDD 2 (voltage of the power supply line PL 2 ) to generate the power supply voltage VDD 1 and supplies the power supply voltage VDD 1 to the power supply line PL 1 .
In the above third embodiment, the operation voltage of the logic block 23 is lower than the operation voltage of the memory block 14 , and an internal power supply system of the semiconductor device 30 is separated into two systems: a power supply system for the memory block 14 (power supply system of the power supply voltage VDD 1 generated by the boost circuit 32 ) and a power supply system for the logic block 23 (power supply system of the power supply voltage VDD 2 generated by the power supply circuit 31 ), and also in such a case, the same effect as in the above first embodiment can be obtained.
Incidentally, in the second embodiment, the example in which the operation voltage of the logic block 23 is lower than the operation voltage of the memory block 14 and the step-down circuit 22 which supplies the voltage (power supply voltage VDD 2 ) obtained by stepping down the voltage (power supply voltage VDD 1 ) of the power supply line PL 1 to the power supply line PL 2 is provided is described, but the present invention is not limited to this embodiment. Also when, for example, the operation voltage of the logic block 23 is higher than the operation voltage of the memory block 14 and instead of the step-down circuit 22 , a boost circuit which supplies a voltage obtained by boosting the voltage of the power supply line PL 1 to the power supply line PL 2 is provided, the same effect can be obtained.
Further, in the third embodiment, the example in which the operation voltage of the logic block 23 is lower than the operation voltage of the memory block 14 and the boost circuit 32 which supplies the voltage (power supply voltage VDD 1 ) obtained by boosting the voltage (power supply voltage VDD 2 ) of the power supply line PL 2 to the power supply line PL 1 is provided is described, but the present invention is not limited to this embodiment. Also when, for example, the operation voltage of the logic block 23 is higher than the operation voltage of the memory block 14 and instead of the boost circuit 32 , a step-down circuit which supplies a voltage obtained by stepping down the voltage of the power supply line PL 2 to the power supply line PL 1 is provided, the same effect can be obtained.
The invention is not limited to the above embodiments and various modifications may be made without departing from the spirit and scope of the invention. Any improvement may be made in part of all of the components.
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A cut-off circuit cuts off supply of a power supply voltage from a voltage supply circuit to a non-volatile memory block. A discharge circuit discharges an electric charge accumulated in stability capacitance. In a data retention test of the memory block, a self test circuit instructs the cut-off circuit to start operation after writing predetermined data into the memory block, and instructs the cut-off circuit to stop the operation to check retention of the predetermined data in the memory block in a predetermined time after the instruction to the cut-off circuit to start the operation. Further, in the data retention test of the memory block, the self test circuit instructs the discharge circuit to start operation along with the instruction to the cut-off circuit to start the operation, and instructs the discharge circuit to stop the operation along with the instruction to the cut-off circuit to stop the operation.
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US GOVERNMENT RIGHTS
[0001] The invention was made with US Government support under contract W911W6-08-2-0001 awarded by the US Army. The US Government has certain rights in the invention.
BACKGROUND
[0002] The disclosure relates to investment casting. More particularly, it relates to the investment casting of superalloy turbine engine components.
[0003] Investment casting is a commonly used technique for forming metallic components having complex geometries, especially hollow components, and is used in the fabrication of superalloy gas turbine engine components. The disclosure is described in respect to the production of particular superalloy castings, however it is understood that the disclosure is not so limited.
[0004] Gas turbine engines are widely used in aircraft propulsion, electric power generation, and ship propulsion. In gas turbine engine applications, efficiency is a prime objective. Improved gas turbine engine efficiency can be obtained by operating at higher temperatures, however current operating temperatures in the turbine section exceed the melting points of the superalloy materials used in turbine components. Consequently, it is a general practice to provide air cooling. Cooling is provided by flowing relatively cool air from the compressor section of the engine through passages in the turbine components to be cooled. Such cooling comes with an associated cost in engine efficiency. Consequently, there is a strong desire to provide enhanced specific cooling, maximizing the amount of cooling benefit obtained from a given amount of cooling air. This may be obtained by the use of fine, precisely located, cooling passageway sections.
[0005] The cooling passageway sections may be cast over casting cores. Ceramic casting cores may be formed by molding a mixture of ceramic powder and binder material by injecting the mixture into hardened steel dies. After removal from the dies, the green cores are thermally post-processed to remove the binder and fired to sinter the ceramic powder together. The trend toward finer cooling features has taxed core manufacturing techniques. The fine features may be difficult to manufacture and/or, once manufactured, may prove fragile. Commonly-assigned U.S. Pat. Nos. 6,637,500 of Shah et al. and 6,929,054 of Beals et al and Pre-grant Publication 2007/261814 of Luczak (the disclosures of which are incorporated by reference herein as if set forth at length) disclose use of ceramic and refractory metal core combinations.
[0006] FIG. 1 shows a trailing edge portion of a turbine airfoil 20 as cast within a shell 22 . For casting the internal passageways, the shell contains a core assembly. The exemplary core assembly includes a ceramic feed core having spanwise legs 30 , 32 , and 34 for casting associated passageway legs. The leg 34 casts a trailing spanwise passageway 36 . The core assembly also includes metallic cores, of which cores 40 , 42 , and 44 are shown. The exemplary metallic cores are formed of refractory metal sheet stock. The core 40 forms a pressure side outlet circuit, the core 42 forms a suction side outlet circuit, and the core 44 forms a trailing edge outlet slot 50 . The outlet slot 50 is fed from the passageway 36 . During core assembly, a leading portion of the core 44 is secured within a mating slot of the trailing leg 34 of the ceramic core.
SUMMARY
[0007] One aspect of the disclosure involves a method for manufacturing an investment casting core from a metallic blank. The blank has a thickness between parallel first and second faces less than a width and length transverse thereto. The blank is locally thinned from at least one of the first and second faces. The blank is through-cut across the thickness. The blank is inserted into the leading portion into a slot in a pre-formed ceramic core.
[0008] In various implementations, through-cutting may comprise at least one of laser cutting, liquid jet cutting, and EDM. The thinning may comprise at least one of EDM, ECM, MDP, and mechanical machining.
[0009] In an investment casting method, the investment casting core may be at least partially overmolded by a pattern-forming material for forming a pattern. The pattern may be shelled. The pattern-forming material may be removed from the shelled pattern for forming a shell. Molten alloy may be introduced to the shell. The shell may be removed. The method may be used to form a gas turbine engine component. An exemplary component is an airfoil wherein the core forms trailing edge outlet passageways.
[0010] Another aspect of the disclosure involves an investment casting core having a metallic core element and a ceramic core. The metallic core element has a tapered leading portion, an intermediate portion downstream of the tapered leading portion, and a trailing portion downstream of the intermediate portion and thicker than the intermediate portion. The ceramic casting core has a slot receiving the leading portion.
[0011] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a partial streamwise sectional view of a trailing edge portion of a prior art airfoil cast within a ceramic shell.
[0013] FIG. 2 is a partial streamwise sectional view of a modified airfoil.
[0014] FIG. 2A is an enlarged view of a portion of FIG. 2 .
[0015] FIG. 3 is a partially schematic/simplified view of a pattern including the core assembly.
[0016] FIG. 4 is a partially schematic/simplified view of a blade cast in a shell formed over the pattern.
[0017] FIG. 5 is an enlarged partial pressure side view of a discharge slot of the blade of FIG. 4 .
[0018] FIG. 6 is a flowchart of a core manufacture process.
[0019] Like reference numbers and designations in the various drawings indicate like elements.
DETAILED DESCRIPTION
[0020] FIG. 2 shows an alternative refractory metal core 60 which has a leading/upstream edge/end 62 and a trailing/downstream edge/end 64 . The exploded view of FIG. 3 shows an inboard end 66 and an outboard end 68 . As is discussed further below, an upstream-most portion 70 extending aft from the leading edge/end 62 is configured to be received within and mate with a trailing slot 72 of a trailing leg 74 of a ceramic feedcore 76 . The RMC 60 has an intermediate portion 80 which casts the majority of the ultimate trailing edge discharge slot. In the exemplary RMC 60 , along this region 80 , the RMC pressure side/surface 82 and suction side/surface 84 are separated by an essentially constant RMC thickness T 1 ( FIG. 2A ). Downstream of the portion 80 , the exemplary RMC thickens. A relatively thick portion 86 having an essentially constant thickness shown as T 3 extends to the trailing end/edge 64 . Of this portion 86 , a smaller upstream portion 88 casts pressure side discharge openings in the airfoil.
[0021] FIG. 3 (a partially schematic/simplified view of a pattern) shows the portion 80 having holes 100 for casting posts within the slot. FIG. 3 further shows the portion 88 as having streamwise elongate tapering holes 102 which are interspersed with intact portions 104 . The intact portions 104 cast pressure side openings from the trailing edge discharge slot; whereas the holes 102 cast walls therebetween.
[0022] In the exemplary core assembly, the feedcore slot 72 and RMC portion 70 both have an upstream-ward taper. The exemplary thickness T 2 of the RMC at the leading edge is less than T 1 (e.g., 30-60%). The exemplary RMC taper is essentially constant at an angle of θ 1 over a streamwise length L 1 . The exemplary taper is provided by relieving/beveling only one of the two faces 82 and 84 (the face 84 in the exemplary embodiment with a bevel facet/surface 110 ). The exemplary relief provides the taper angle θ 1 . Exemplary θ 1 are 0.1-3.0°, more narrowly 1.0-2.5°. Exemplary taper length L 1 is coincident with or slightly less than a depth D 1 of the slot. The exemplary slot has an opening 120 having a height H 1 which may be greater than T 1 and has a base 122 with a height H 2 which is greater than T 2 . A portion of the slot between respective slot walls 124 and 126 and the RMC may be filled with an adhesive or slurry 130 . The exemplary streamwise cross-section of the RMC is shown as generally arcuate with concavity along the pressure side and convexity along the suction side so as to correspond to a median of the airfoil cross-section.
[0023] Exemplary L 1 is 0.040-0.100 inch (1-2.5 mm), more narrowly 0.050-0.075 inch (1.3 mm-9 mm). Exemplary T 1 is 0.012 inch (0.3 mm), more broadly 0.005-0.020 inch (0.13-0.5 mm) or 0.010-0.015 inch (0.25-0.38 mm). Exemplary T 2 is 0.005 inch (0.13 mm), more broadly 0.002-0.015 inch (0.05-0.38 mm) or 0.003-0.007 inch (0.08-0.18 mm) or 25-75% of T 1 , more narrowly, 40-60%. Exemplary T 3 is 0.035 inch (0.9 mm), more broadly 0.020-0.050 inch (0.5-1.3 mm) or 200-500% of T 1 , more narrowly 250-400%. Exemplary feedcore thickness at either side of the slot base 122 (shown as T 4 to the pressure side and T 5 to the suction side) may be at least 0.018 inch (0.46 mm), more narrowly 0.018-0.040 inch (0.46-1.0 mm) or 0.08-0.025 inch (0.46-0.64 mm).
[0024] In an exemplary sequence 200 of manufacture ( FIG. 6 ), the RMC 84 may be machined from a strip having a thickness equal to T 3 , a greater width, and a yet greater length. In an initial stage of manufacture, gross thickness features may be machined 202 to provide the thickness T 1 of the intermediate portion and provide the bevel/taper. Specifically, the exemplary machining is from the pressure side face 82 to define the intermediate portion and from the suction side face 84 to provide the taper of the leading portion. However, the step 202 may easily be further divided. Exemplary machining may be mechanical machining or may be an abrasive grinding, electrodischarge machining (EDM), electrochemical machining (ECM), or a molecular decomposition process (MDP).
[0025] Additionally, a series of through-cuts are cut 206 to define the holes/apertures 100 for forming posts 150 ( FIG. 4 ) within the outlet slot and holes/apertures 102 for forming trailing dividing walls 152 along the slot outlet 154 at the trailing edge 156 . FIG. 4 further shows: the airfoil 160 having a leading edge 162 and a tip 164 ; the platform 170 at the inboard end of the aitrfoil; and the firtree attachment root 172 depending from the underside of the platform. The root has the inlet ports 174 to the trunks of the cooling passageway network (cast over the ceramic feedcore trunks). FIG. 5 shows the outlet 154 as including a spanwise array of segments/portions/openings 180 along the airfoil pressure side between associated pairs of the dividing walls 152 . As is discussed above, the openings 180 are cast by the intact portions 104 of the RMC portion 88 of FIG. 2 . A curving transition 89 ( FIG. 2 ) between the RMC portions 80 and 86 / 88 casts a curving transition 182 ( FIG. 5 ) between a main portion 184 of the slot and the openings 180 .
[0026] Exemplary cutting may be via a punching/stamping operation or, alternatively, mechanical drilling, laser cutting, liquid jet cutting, and/or EDM. To provide the RMC in the desired arcuate shape corresponding to the airfoil median 500 , the RMC is bent 208 (e.g., via stamping). This bending may also form a spanwise variation (e.g., to accommodate a varying relationship in the position of the feedcore relative to the discharge slot) such as creating a net spanwise twist. An exemplary stamping is performed via one or more pressing stages in custom presses having opposing die faces contoured to mate with the RMC. The RMC may be coated 210 with a protective coating. Alternatively a coating could be applied pre-assembly. Suitable coating materials include silica, alumina, zirconia, chromia, mullite and hafnia. Preferably, the coefficient of thermal expansion (CTE) of the refractory metal and the coating are similar. Coatings may be applied by any appropriate line-of-sight or non-line-of sight technique (e.g., chemical or physical vapor deposition (CVD, PVD) methods, plasma spray methods, electrophoresis, and sol gel methods). Individual layers may typically be 0.1 to 1 mil thick. Layers of Pt, other noble metals, Cr, Si, W, and/or Al, or other non-metallic materials may be applied to the metallic core elements for oxidation protection in combination with a ceramic coating for protection from molten metal erosion and dissolution.
[0027] The ceramic core may be (e.g., silica-, zircon-, or alumina-based) molded 212 . The as-molded ceramic material may include a binder. The binder may function to maintain integrity of the molded ceramic material in an unfired green state. Exemplary binders are wax-based. After the molding 212 , the preliminary core assembly may be debindered/fired 214 to harden the ceramic (e.g., by heating in an inert atmosphere or vacuum). The slot 72 may have been formed as part of the molding 212 or may be cut in the ceramic (e.g., in the green state or in the fired state). The RMC may be inserted 216 into the ceramic core to assemble and an adhesive or slurry introduced 218 .
[0028] FIG. 6 shows an exemplary method 220 for investment casting using the core assembly. Other methods are possible, including a variety of prior art methods and yet-developed methods. The fired core assembly is then overmolded 230 with an easily sacrificed material such as a natural or synthetic wax (e.g., via placing the assembly in a mold and molding the wax around it). There may be multiple such assemblies involved in a given mold.
[0029] The overmolded core assembly (or group of assemblies) forms a casting pattern with an exterior shape largely corresponding to the exterior shape of the part to be cast. The pattern may then be assembled 232 to a shelling fixture (e.g., via wax welding between end plates of the fixture). The pattern may then be shelled 234 (e.g., via one or more stages of slurry dipping, slurry spraying, or the like). After the shell is built up, it may be dried 236 . The drying provides the shell with at least sufficient strength or other physical integrity properties to permit subsequent processing. For example, the shell containing the invested core assembly may be disassembled 238 fully or partially from the shelling fixture and then transferred 240 to a dewaxer (e.g., a steam autoclave). In the dewaxer, a steam dewax process 242 removes a major portion of the wax leaving the core assembly secured within the shell. The shell and core assembly will largely form the ultimate mold. However, the dewax process typically leaves a wax or byproduct hydrocarbon residue on the shell interior and core assembly.
[0030] After the dewax, the shell is transferred 244 to a furnace (e.g., containing air or other oxidizing atmosphere) in which it is heated 246 to strengthen the shell and remove any remaining wax residue (e.g., by vaporization) and/or converting hydrocarbon residue to carbon. Oxygen in the atmosphere reacts with the carbon to form carbon dioxide. Removal of the carbon is advantageous to reduce or eliminate the formation of detrimental carbides in the metal casting. Removing carbon offers the additional advantage of reducing the potential for clogging the vacuum pumps used in subsequent stages of operation.
[0031] The mold may be removed from the atmospheric furnace, allowed to cool, and inspected 248 . The mold may be seeded 250 by placing a metallic seed in the mold to establish the ultimate crystal structure of a directionally solidified (DS) casting or a single-crystal (SX) casting. Nevertheless the present teachings may be applied to other DS and SX casting techniques (e.g., wherein the shell geometry defines a grain selector) or to casting of other microstructures. The mold may be transferred 252 to a casting furnace (e.g., placed atop a chill plate in the furnace). The casting furnace may be pumped down to vacuum 254 or charged with a non-oxidizing atmosphere (e.g., inert gas) to prevent oxidation of the casting alloy. The casting furnace is heated 256 to preheat the mold. This preheating serves two purposes: to further harden and strengthen the shell; and to preheat the shell for the introduction of molten alloy to prevent thermal shock and premature solidification of the alloy.
[0032] After preheating and while still under vacuum conditions, the molten alloy is poured 258 into the mold and the mold is allowed to cool to solidify 260 the alloy (e.g., after withdrawal from the furnace hot zone). After solidification, the vacuum may be broken 262 and the chilled mold removed 264 from the casting furnace. The shell may be removed in a deshelling process 266 (e.g., mechanical breaking of the shell).
[0033] The core assembly is removed in a decoring process 268 to leave a cast article (e.g., a metallic precursor of the ultimate part). The cast article may be machined 270 , chemically and/or thermally treated 272 and coated 274 to form the ultimate part. Some or all of any machining or chemical or thermal treatment may be performed before the decoring.
[0034] One or more embodiments have been described. Nevertheless, it will be understood that various modifications may be made. For example, the principles may be implemented using modifications of various existing or yet-developed processes, apparatus, or resulting cast article structures (e.g., in a reengineering of a baseline cast article to modify cooling passageway configuration). In any such implementation, details of the baseline process, apparatus, or article may influence details of the particular implementation. Accordingly, other embodiments are within the scope of the following claims.
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A method for manufacturing an investment casting core uses a metallic blank having a thickness between parallel first and second faces less than a width and length transverse thereto. The blank is locally thinned from at least one of the first and second faces. The local thinning forms a taper on a leading portion of the RMC. The blank is through-cut across the thickness. The blank is inserted into the leading portion into a slot in a pre-formed ceramic core.
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BACKGROUND OF THE INVENTION
The present invention relates to apparatus for use in driving tunnels, galleries, trenches -- open or otherwise, similar excavations and for convenience referred to hereinafter as "tunnels or the like".
When tunnels or the like are being formed in water-bearing strata by conventional apparatus it is known to utilize ancillary equipment including suction lances to withdraw water from the working. The use of such equipment is complicated, time consuming and costly and adversely affects the efficiency of the overall operation. There is thus a need for an improved form of apparatus and a general object of this invention is to provide such an apparatus.
SUMMARY OF THE INVENTION
In its broadest aspect the invention provides apparatus for use in driving tunnels or the like; said apparatus having an advanceable drive shield provided with devices extendible from the front of the shield to treat the working face. The treatment of the working face contemplated by the invention is primarily, but not exclusively withdrawing water by suction and processes such as ejecting fluid under pressure against the face to assist in breaking up the face. Accordingly in another aspect the invention provides apparatus for use in driving tunnels or the like; said apparatus having an advanceable drive shield provided with hollow devices extendible from the front of the shield to treat the working face by withdrawing water or by conveying fluid under pressure thereto.
Preferably means such as cams or the like are provided for selectively locking the devices in various positions and/or for automatically extending the devices at certain stages during the driving operation. In the case where the drive shield is of continuous cylindrical form, the devices can be distributed around the periphery of the shield and movable therewith. The extension of the devices for operation can then be effected manually or by a suitable mechanism such as an hydraulic unit or units or by spindles or the like.
Where the drive shield is composed of a plurality of elongate drive members mounted side-by-side on a support frame which supports and guides the members for longitudinal displacement the invention can be realized by making at least some of these drive members hollow and by mounting the devices for movement longitudinally of these members. To this end guides can be provided in the hollow members with the devices located in the guides for telescopic movement.
The provision of the devices enables various operations, such as the water removal and other face treatment referred to above to be performed efficiently. Nevertheless, the devices may not be needed in some circumstances and here it is convenient to retract the devices inside the members or the shield and to close off the guides with suitable covers or flaps. It is desirable, however, to provide for removal or insertion of the devices from the rear of the members or the shield by leaving the shield or the members and the guides open at the rear end. Thus where the devices are not needed at all they can be withdrawn from the members or the shield quite easily.
Where the drive shield is composed of drive members supported on a frame, means such as hydraulic rams are usually provided to alternatively move the members, individually or in groups and the frame in the advancing direction towards the working face. It is then desirable to design the apparatus so that the relative movement between the members and the frame extends the devices forwardly. To this end means, such as cams or the like can be arranged between the frame and the devices so as to engage and extend the devices when the frame is shifted up. In one constructional form, a series of projections can be provided on each device which ride over a spring-biased stop carried by the frame in the manner of a ratchet. When the device is moved with its drive member the stop may then engage on one of the projections to prevent the retraction of the device and thereby ensure the device is moved with the frame to extend from the drive member as the frame is shifted. The projections and the associated stop may have interengageable faces designed to engage and to inhibit movement of the device.
Preferably the stops are mounted for swivelling so that the stops can be orientated to allow or inhibit retraction of the devices into the drive members. To avoid interference with the displacement of the drive members, the stops of the frame can be mounted in sleeves which project through slotted apertures in the members. The drive members may also each have a spring-biased stop similar to those of the frame and engageable with the projections of its associated device to permit or inhibit movement of the device relative to the drive member and the guide. Again it is preferable to mount the stops of the drive members for swivelling so that the stops can be orientated to allow or inhibit retraction of the devices into the drive members. As with the stops of the frame, the stops of the drive members can be located in sleeves and slots in the guides can receive the projections.
The provision for swivelling of the stops enables the devices to remain inactive within the drive members whenever desired and the facility for automatic extension of the devices will be rendered inoperative. Nevertheless, the devices can be extended manually or the stops easily re-orientated by a wrench or other suitable tool when the automatic extension facility is again desired. The stops can reliably prevent the devices from retracting under the reactive pressure from the working face but again by re-orientating the stops the devices can be allowed to retract whenever desired.
The characteristic of re-orientating the stops for different actions on the devices can be achieved by providing faces both perpendicular and diametric to the tunnel axis and inclined thereto on the stops and the projections. Thus each projection may have an inclined front face and a perpendicular rear face while each stop may have an inclined rear face and a perpendicular front face when orientated to inhibit retraction of the device. The stop may then be swivelled through 180° to bring its inclined face to the front thereby allowing the passage of a projection or projections and the retraction of the device in question.
As will become apparent hereinafter the invention also provides apparatus for use in driving tunnels or the like and comprising a plurality of elongate drive members arranged side-by-side, a frame supporting the members for longitudinal displacement, means for relatively shifting the members and the frame to effect advancement of the tunnel, devices mounted to move with at least some of the drive members and means for automatically extending said devices from the drive members when the frame is shifted relative to the member to thereby bring the devices into a position for treating the working face in front of the drive members.
The invention may be understood more readily, and various other features of the invention may become apparent, from consideration of the following description.
BRIEF DESCRIPTION OF DRAWINGS
Embodiments of the invention will now be described, by way of examples only, with reference to the accompanying drawings, wherein:
FIGS. 1 to 3 are sectional side views of a single drive member of a drive shield of apparatus made in accordance with the invention showing the components thereof in different operating positions; and
FIGS. 4 and 5 are views generally corresponding to FIGS. 1 to 3 and showing a modified extendible device in different operating positions.
DESCRIPTION OF PREFERRED EMBODIMENTS
In general, apparatus constructed in accordance with the invention and as described hereinafter is used in driving tunnels, galleries, trenches or similar excavations especially in water-bearing soil. As shown in the drawings, and as is generally known in the art, the apparatus has a rigid support frame 10 which supports and slidably guides a plurality of elongate drive members 14 also referred to as knives or planks. The members 14 are arranged side-by-side in parallel relationship in contact with the wall of the tunnel or other excavation to form a shield. The members 14 are each individually displaceable in a longitudinal sense in the tunnel driving direction V (FIG. 1). The frame 10 is here composed of two ring structures 11, 12 spaced apart in the driving or advancement direction V and interconnected by means of longitudinal and diagonal frame parts generally designated 13.
To advance the members 14 and the frame 10, means (not shown) such as double-acting hydraulic rams are provided. Such rams would be normally articulated to the frame 10 and to one, or a group, of the members 14. The rams can then advance the members 14 individually or in groups in succession. When the members 14 have been advanced in the direction V by the working stroke of the rams the frame 10 would be shifted up to follow the advanced members 14. In this frame-shifting operation the rams would be operated in unison in a reverse sense with the members 14 lying in frictional contact with the tunnel wall acting as an abutment. The sequence would then be repeated. The foregoing features are well known per se.
When the members 14 are advanced they usually penetrate a working face at the front end of the tunnel. Material can be removed and transported away from the face by any known method. In the case where the material is water bearing and otherwise the features which will now be described are especially useful.
In accordance with the invention and as shown in the drawings, the members 14 are of hollow boxlike cross section having an upper or outer surface and a lower or inner surface. A guide 15, conveniently of tubular form, is provided within some or all of the members 14. The guides 15 can be welded into the members 14. A hollow device 16 used for the purposes described hereinafter and again of tubular form is slidably mounted within each guide 15 so as to be extendible and retractible in a telescopic manner. Each guide 15 extends over the entire length of its associated member 14 and is open at the rear end 14 (FIG. 1) to permit the device 16 thereof to be inserted or withdrawn from the rear. Each device 16 is of such a length to permit the device 16 to be fully retracted and housed within its guide 15. At its front end adjacent the working face, each guide 15 is provided with a flap or cover 17 which is hinged and preferably spring biased to its closed position to permit the guide 15 to be closed off or opened to allow the device 16 to extend out therefrom. FIGS. 1 and 2 show the fully retracted position of the device 16 with the cover 17 closing off the guide 15 whereas FIGS. 3 to 5 show the device 16 extending out from the guide 15 with the cover 17 pivoted to an open position.
Each guide 15 has an elongate slot and the associated device 16 has a set of cams or saw-tooth like projections 18 on its exterior which engage through this slot. The front faces 19 of these projections 18 are inclined as shown whereas the rear faces of the projections 18 are perpendicular or diametric to the tunnel axis. The foremost ring structure 11 of the frame 10 is provided with radial sleeves 21 each slidably guiding a cam follower or complementary stop 20 engageable with the projections 18 of an associated device 16. The sleeves 21 also accommodate springs 22 which resiliently bias the stops 20 outwardly perpendicular to the driving direction V. The stops 20 each have a rear face 23 inclined as shown to correspond with the faces 19 of the associated projections 18 and a front face perpendicular to the tunnel axis. The sleeves 21 project through slots 24 (FIG. 1) in the members 14 provided with the guides 15 so that these members 14 can be displaced in relation to the frame 10 as described hereinbefore without hinderance by the sleeves 21. The members 14 provided with guides 15 are also provided with further sleeves 28 at their central regions. In a similar manner to the sleeves 21, each sleeve 28 slidably guides a further cam follower or complementary stop 25 engageable with the projections 18 of the associates device 16. The sleeves 28 similarly accommodate springs 27 which resiliently bias the stop 25 outwardly perpendicular to the driving direction V. As with the stops 20, the stops 25 each have a rear face 26 which is inclined to correspond with the faces 19 of the projections 18 as well as a front perpendicular face. Engagement between the relatively moving faces 19, 23 or 19, 26 will tend to urge the stops 20, 25 inwards.
However the stops 20, 25 are each capable of being swivelled through 100° about the axis 29 (FIGS. 4 and 5) of the sleeves 21, 28 to thereby bring the inclined faces 23, 26 to the front. In this case engagement between these faces 23, 26 and the relatively moving rear faces of the projections 18 will again tend to move the stops 20, 25 inwards. Preferably detents or the like bias the stops 20, 25 into the two alternative positions. In general, therefore the devices 16 can be extended or retracted as desired. Nevertheless, the arrangement is such as to enable the devices 16 to be extended automatically as the drive shield advances as will now be described.
As shown in FIG. 1, the device 16 depicted therein is completely retracted within the member 14 and the cover 17 closes the front end of the guide 15. The front or first projection 18 is disposed between the stops 20, 25 and the second projection 18 from the front has its rear face closely adjacent the front face of the stop 25. As will be appreciated the following description is related to the single member 14 depicted in the drawings but the same sequence of events occurs with all the members 14 provided with the guides 15 and devices 16.
FIG. 2 shows the components after the member 14, in question has been shifted up in the direction V.
During the advancing of the member 14 the front face 19 of the first projection 18 engages with the rear face 23 of the stop 20 thereby urging the stop 20 inwards to permit the device 16 and the member 14 to shift until the stop 20 is free of the projection 18 whereupon the spring 22 biases the stop 20 outwards again so that the rear face of the projection 18 is closely adjacent the front face of the stop 20 as shown in FIG. 2. The stop 25 maintains its positional relationship with the second projection 18 as also shown. It will be recalled that when the members 14 have all been advanced the frame 10 is shifted up.
FIG. 3 shows the positional relationships when the frame 10 has been shifted up. As can be appreciated from FIGS. 2 and 3 as the frame 10 is displaced the front face of the stop 20 engages on the rear face of the front projection 18 so that the device 16 is extended with the frame 10. The cover 17 is automatically pivoted by the extending device 16 although it is possible to open the cover 17 separately. As the device 16 extends the front face 19 of the third projection 18 from the front engages the rear face 26 of the stop 25 and the stop 25 is urged inwards by the projection 18 against the force of the spring 27 to permit the extension of the device 16. When the device 10 has been advanced with the frame 10 in this manner the first and third projections 18 have their rear faces in abutting relationship with the front faces of the stops 20, 25 thereby preventing inward movement of the device 16 under reactive force from the working face. By swivelling the stops 20, 25 through 180° with a suitable tool the device 16 can be unlocked so that it will be retracted by the reactive pressure of the face or otherwise.
The devices 16 can be connected up to a suction pump in order to withdraw water from the face. Alternatively a source of compressed air or water under pressure can be connected to the devices to assist in breaking up the face. Other forms of treatment are also possible.
If the device 16 is to maintain the extended position shown in FIG. 3 the stop 20 would be swivelled back and forth through 180° so that the device 16 advances with the member 14 but the movement of the frame 10 does not cause further extension of the device 16. It is possible to design the cover 17 so that it permits the passage of the first projection 18 thereby permitting the device 16 to be extended further from the position shown in FIG. 3. Alternatively, as representated in FIGS. 4 and 5, the projections 18 can be positioned closer to the rear of the device 16 as compared with FIGS. 1 to 3. In this case after shifting of the member 14 the device 16 would adopt the position shown in FIG. 4 (c.f. FIG. 2) and when the frame 10 is shifted the device 16 would be further extended by the stop 20 with the third projection 18 riding over the stop 25 to finish up in the position shown in FIG. 5.
|
Tunnel-driving apparatus utilizes a plurality of elongate drive or knife members arranged side-by-side and supported and guided for longitudinal movement on a frame. The members and the frame are advanced in succession during the driving process. Some or all of the drive members are hollow and accommodate telescopically extendible and retractible devices, conveniently of tubular form, used for treating the working face, for example, by conveying fluid to or from the face. The devices each have a series of cam-like projections engageable with spring-biased stops supported on the frame and the drive members. These stops serve to lock the devices in various positions and to automatically extend the devices from the members when the frame is shifted.
The stops can be displaced however to generally engage the projections in such manner as to allow or prevent movement of the devices inwardly or outwardly of the drive members.
| 4
|
FIELD
[0001] The present disclosure relates generally to materials useful to prevent wear on surfaces subjected to abrasion, impact and high temperatures and methods of using those materials. In one embodiment the present disclosure relates to materials useful to prevent wear on coal burners and methods of using those materials.
BRIEF DESCRIPTION OF RELATED TECHNOLOGY
[0002] Thermal power plants run continuously 24 hours a day, 7 days a week burning pulverized coal in large furnaces to generate steam that drives turbines to generate electricity. Coal tip burners are primarily used to direct the pulverized coal to predetermined position in the center of the furnace. The coal is burned as a fire ball in this predetermined position. Coal tip burners are required to work continuously in a very harsh environment of high temperature and constant abrasion. Coal tip burners see continuous temperature of 700° C. to 800° C. and intermittent temperatures up to 1200° C. The pulverized coal is very abrasive and travels at 15-35 ton/hr through coal tip. The coal tip also sees occasional impact from larger pieces of coal.
[0003] These harsh conditions cause baffle plates in the coal tip burners to wear out in less than 6 months. The worn baffle plate negatively affects the pulverized coal flow into the furnace changing fire ball height and lessening efficiency. Unplanned replacement of coal tip burners is expensive as it requires shutdown of the facility. Planned replacement during a shut down is also expensive due to the size of the coal burner tip and difficulty in accessing the burner tip within the power plant.
[0004] Silica dispersion or colloidal silica and ceramic based coatings are known for their high temperature properties (>2000° C.) and are used in furnaces and kilns in steel plants and cement plants. However most of these applications are static where the coating is subjected to a high temperature environment but not impact or abrasion. Silica dispersion or colloidal silica and ceramic based coatings are inherently brittle and have poor impact resistance. Silica dispersion or colloidal silica and ceramic based coatings also have poor adhesion to metals and spall or chip off the base surface when subjected to impact of parts, etc. Despite the high temperature stability, silica dispersion or colloidal silica and ceramic based coatings are not suitable for use as a protective coating on coal tip burners as they tend to spall and break off when exposed to the continuous sliding abrasion and impact of coal particles on the coating.
[0005] Hard facing with tungsten carbide based coatings are also used for such application. However, these coatings are very expensive, require highly trained personnel using specialized equipment and application conditions and can be difficult to apply to all areas. Other methods such as plasma spraying, flame spraying, hot spraying etc. are limited due to complexity in application or limitations like coating thickness etc.
SUMMARY
[0006] The present disclosure relates generally to materials useful to prevent wear on surfaces subjected to abrasion, impact and high temperatures and methods of using those materials. In one embodiment the disclosure provides a method of forming a protective surface for a coal tip burner resistant to high temperatures, abrasion and impact. The protective surface is prepared from curable composition comprising a silica dispersion or colloidal silica used in conjunction with a reinforcing support. In one embodiment the reinforcing support is a metal mesh or screen attached to a coal tip burner baffle plate. The curable composition is applied over and through the reinforcing support. This curable composition develops very good green strength after setting at room temperature (R.T) and develops additional strength after heat curing at temperatures above room temperature. Its full strength is developed once it is fired at temperature of >800-1000° C.
[0007] It is observed that the curable composition, when applied to a cleaned steel substrate without the reinforcing support, does not have good adhesion and the cured coating delaminates easily from the substrate after a single drop from <1 meter. The combination of curable silica dispersion or colloidal silica based composition applied over a reinforcing support attached to the substrate surface and cured has good adhesion and impact resistance and withstands more than 10 drops from a height of 1-2 meter without chipping and separating from the base substrate.
[0008] The disclosed compositions include any and all isomers and steroisomers. In general, unless otherwise explicitly stated the disclosed materials and processes may be alternately formulated to comprise, consist of, or consist essentially of, any appropriate components, moieties or steps herein disclosed. The disclosed materials and processes may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants, moieties, species and steps used in the prior art compositions or that are otherwise not necessary to the achievement of the function and/or objective of the present disclosure.
[0009] When the word “about” is used herein it is meant that the amount or condition it modifies can vary some beyond the stated amount so long as the function and/or objective of the disclosure are realized. The skilled artisan understands that there is seldom time to fully explore the extent of any area and expects that the disclosed result might extend, at least somewhat, beyond one or more of the disclosed limits. Later, having the benefit of this disclosure and understanding the concept and embodiments disclosed herein, a person of ordinary skill can, without inventive effort, explore beyond the disclosed limits and, when embodiments are found to be without any unexpected characteristics, those embodiments are within the meaning of the term about as used herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Referring now to the drawings wherein like elements are numbered alike in the several Figures:
[0011] FIG. 1 is a schematic view of one embodiment of a portion of a coal tip burner.
[0012] FIG. 2 is a schematic, broken away view showing a reinforcing support on a section of baffle plate with disclosed composition applied over a portion of the baffle plate and reinforcing support.
[0013] FIG. 3 is a schematic, cross sectional view of a portion of a baffle plate with attached reinforcing support and disclosed composition disposed thereon.
DETAILED DESCRIPTION
[0014] As shown in FIG. 1 , one embodiment of a coal tip burner 2 comprises an outer shell 4 . A plurality of baffle plates, each 6 , are disposed within the outer shell and attached thereto by a plurality of stays, each 8 . The baffle plates 6 and stays 8 are generally planar metal sections. Typically the baffle plates 6 are made from stainless steel or another metal that will retain strength and abrasion resistance at the high working temperatures the coal tip burner 2 is exposed to during use. The baffle plates have wear surfaces 10 that are in contact with pulverized coal during use.
[0015] As shown in FIG. 2 a reinforcing support 14 is attached to a surface 10 of the coal tip burner 2 where enhanced abrasion resistance is desired. In one advantageous embodiment the reinforcing support 14 comprises a plurality of intersecting metal elements, each 16 , such as wires that form a screen or grid or mesh. The reinforcing support 14 can be attached to surfaces 10 of the baffle plate by, for example, welding. Spot welds, each 18 , of the reinforcing support 14 to the surface 10 at spaced locations have been found suitable. The reinforcing support 14 can be formed from a metal that can be welded to the surface 10 . The reinforcing support material should also retain strength at the high working temperatures the coal tip burner is exposed to during use. Metals such as stainless steel have been found suitable for use as a reinforcing support 14 material.
[0016] A silica dispersion or colloidal silica based composition 22 is disposed over the surface 10 and attached reinforcing support 14 . The silica dispersion or colloidal silica based composition 22 will be a semi-fluid or paste-like or putty-like like material that can be handled using conventional techniques and equipment for such materials. The composition 22 is disposed into the spaces between the intersecting metal elements 16 and down to the surface 10 . Typically the silica dispersion or colloidal silica based composition 22 will form a wear resistant surface 24 , shown best in FIG. 3 . Thickness of the composition 22 layer will be a function of the metal element 16 size and desired wear resistance. Cured composition 22 thicknesses of 1 mm to 10 mm, advantageously 3 mm to 6 mm over surface 10 are believed to be useful in significantly reducing wear on baffle plates 6 during use.
[0017] The silica dispersion or colloidal silica based composition 22 disposed on the surface 10 and support 14 must cure before use. The disposed composition 22 will cure at room temperature to a green or semi-hard state. The green cured composition will be a hard, monolithic mass that can no longer be applied or used. The plate 6 , reinforcing support 14 and composition 22 can be handled when the composition 22 is in the green cure state. In some embodiments the composition in the green cure state has a compressive strength (ASTM D-695 at 25° C.) of 5 to 15 mPa and advantageously 10 to 15 mPa.
[0018] Exposure of the composition 22 , either shortly after application or in the green cure state, to temperatures above room temperature will further increase strength of the composition 22 . Raising the temperature above room temperature shortens the time required to cure the composition 22 . Curing can be done by exposing the silica dispersion or colloidal silica based composition 22 disposed on the surface 10 and support 14 to room temperature for about 12 to 36 hours and advantageously about 24 hours. Alternatively, the silica dispersion or colloidal silica based composition 22 disposed on the surface 10 and support 14 can be exposed to room temperature for about 12 to 36 hours followed by exposure to a temperature above room temperature for a shorter time. An elevated temperature of 90 to 200° C. for a time of 1 to 8 hours has been found useful to increase strength. In some embodiments the composition in the fully cured (after firing at 800 ° C.) state has a compressive strength (ASTM D-695 at 25° C.) of 45 to 65 mPa and advantageously 55 to 60 mPa.
[0019] The silica dispersion or colloidal silica based composition 22 typically comprises multiple parts that must be stored separately to prevent unwanted curing. In some embodiments the silica dispersion or colloidal silica based composition 22 has three separately stored parts. In some embodiments the silica dispersion or colloidal silica based composition 22 has two separately stored parts. Just before use the multiple parts are mixed and the mixed composition 22 is applied to the reinforcing support 14 and surface 10 . The mixed composition 22 can have a pot life of 10 minutes to an hour or more before it has cured to the point where it is no longer capable of being applied.
[0020] The composition 22 includes a colloidal silica part. There are many grades of colloidal silica, but all of them are composed of silica particles ranging in size from about 1 nm up to about 150 nm. These particles are typically spherical in shape, and they may be present as discrete particles or slightly structured aggregates. These particles may also be present in a narrow or wide particle size range—depending on the process by which they were created. Colloidal silica can come as a low viscosity dispersion of silica particles in fluid. The maximum weight fraction of silica in the dispersion is limited based on the average particle size. Dispersions with a smaller average diameters have larger overall specific surface areas and are limited to low concentration dispersions. Conversely, dispersions with larger average diameters have lower smaller overall specific surface areas and are available in more concentrated dispersions. The appearance of colloidal silica dispersion depends greatly on the particle size. Dispersions with small silica particles (<10 nm) are normally quite clear. Midsize dispersions (10-20 nm) start to take on an opalescent appearance as more light is scattered. Dispersions containing large colloidal silica particles (>50 nm) are normally white. Dispersion stability can also be enhanced with surface modification of the colloidal silica particles to incorporate functional groups such as silanes. The silanol groups can be isolated silanol groups or silanediol groups or vicinal types. Despite the fact that colloidal silica has the same chemical formula (SiO2) as quartz or sand, colloidal silica has very different properties from larger size quartz particles and colloidal silica provides compositions with very different properties from the same composition using larger size quartz particles.
[0021] Useful colloidal silica can be a dispersion of 20-40% of 20 nanometer to 100 nanometer silica particles in a liquid phase. The liquid phase typically comprises water and materials such as surfactants to help keep the silica particles dispersed. BINDZIL 401/170 or 40/220 or CC401 colloidal silica from Akzo Nobel and AREMCO 644s colloidal silica from Aremco have been found useful in the inventive compositions.
[0022] The composition 22 includes a filler and aggregate part. This part comprises a mixture of different fillers, metal and ceramic powders and inorganic or ceramic aggregate materials. Material size for components in this part is chosen to provide a final uncured composition that can be readily applied to the support and to provide a final cured composition on the support with desired wear resistant properties. Suitable sizes range from particle sizes of 0.010 inches (500 mesh) to 0.1 inches (7 mesh). Beads or aggregate materials can be larger than 0.1 inches.
[0023] Materials useful in the filler and aggregate part include one or more of alumina powder; ceramic powder; ceramic fiber; metal powder such as steel powder or stainless steel powder; silicon carbide powder; crystalline silica powder; ceramic beads; accicular shaped alumina powder; calcium metasilica dispersion or colloidal silica (CaSiO 3 or Wollastonite) powder; engineered ceramic fibers and metal oxides such as copper oxide, titanium oxide and iron oxide.
[0024] The composition 22 includes a cross linker part. This part comprises materials that will bind the mixed composition together by reduction of pH and removal of negatively charged individual particle and or when exposed to heat. Material size for components in this part is chosen to provide a final uncured composition that can be readily applied to the support and to provide a final cured composition on the support with desired wear resistant properties. Commercially available powders are suitable. Materials useful in the cross linker part include one or more of magnesium oxide (MgO); sodium dihydrogen orthophosphate (Na 2 HPO 4 ); sodium silica fluoride (NaSiF 6 ); and sodium borate.
[0025] The composition 22 can optionally include a fluid. The fluid is beneficial in extending open time of the mixed compositions. Suitable fluids include water and organic liquids. Organic liquids having a boiling point above 40° C. can be used as part or all of the fluid part. The fluid part can be separate from the other parts or incorporated into one part, into more than one part or into the final mixture, for example the fluid part can be incorporated into the filler and/or aggregate part and/or the cross-linker part.
[0026] The composition 22 advantageously avoids the use of organic gelation agents such as formaldehyde, formamide, paraformaldehyde, glyoxal, methyl formate, methyl acetate, ethyl formate and ethyl acetate.
[0027] The following components, parts and compositions would be useful in the invention.
[0000]
range
preferred
Component
(pbw) 1
range (pbw)
Part A
colloidal silica part
colloidal silica
10-70
10-30
Part B
fillers and aggregates
alumina powder
30-70
30-70
metal powder
0-20
5-20
silicon carbide powder
0-40
5-40
crystalline silica powder
ceramic beads
10-70
10-70
accicular shaped alumina (Wollastonite)
0-20
5-20
powder
Wollastonite powder
0-20
5-20
metal oxides
0-5
0.5-5
Part C
cross-linker
magnesium oxide (MgO)
0-2
0.05-2
sodium dihydrogen orthophosphate
0-5
0.05-5
(Na 2 HPO 4 )
sodium silica fluoride (NaSiF 6 )
0-5
0.05-5
sodium borate
0-3
0.05-3
Part D
fluid part
water, organic solvent
0-5
0-3
1 pbw is parts by weight
[0028] In one embodiment the composition 22 comprises separate colloidal silica, filler and aggregate, and cross linker parts and optionally a fluid part. In some embodiments one or more of the parts can be combined as long as storage stability of the mixed parts is retained. In one embodiment the composition 22 comprises separate colloidal silica, filler and aggregate and cross linker parts and the fluid part is incorporated into one of these parts. In one embodiment the composition has a first part comprising colloidal silica and a second part comprising filler and aggregate and cross linker.
[0029] Another embodiment comprises a silica part, a silicate part, a filler and aggregate part, a cross linker part and optionally a fluid part. The filler and aggregate part and the cross linker part may be combined. Addition of a silicate part advantageously provides a composition that can cure to a useful hardness with no post cure heating.
[0030] The silicate part comprises an alkaline silicate such as, for example, calcium silicate, magnesium silicate, potassium silicate and/or sodium silicate. Potassium silicate is advantageously useful.
[0031] The following table exemplifies one variation of this embodiment.
[0000]
range
preferred
Component
(pbw) 1
range (pbw)
Part A
colloidal silica part
colloidal silica
4-30
4-20
Part B
Silicate part
alkaline silicate
2-70
2-30
Part C
fillers and aggregates and cross-linker
part
alumina powder
30-70
30-70
metal powder
0-20
5-20
silicon carbide powder
0-40
5-40
crystalline silica powder
ceramic beads
10-70
10-40
accicular shaped alumina (Wollastonite)
0-20
5-20
powder
Wollastonite powder
0-20
1-20
metal oxides
0-5
0.05-5
magnesium oxide (MgO)
0-2
0.05-2
sodium dihydrogen orthophosphate
0-5
0.05-5
(Na 2 HPO 4 )
sodium silica fluoride (NaSiF 6 )
0-5
0.05-5
sodium borate
0-3
0.05-3
Part D
fluid part
water, organic solvent
0-5
0-3
1 pbw is parts by weight
[0032] In any embodiment the fluid part, if used, can be incorporated into one, two or all of the parts.
[0033] The separate parts are mixed shortly before use to form a final, uncured composition 22 . In some advantageous embodiments the uncured composition 22 will be a pasty to putty-like material comprising about 50% to about 90% solids, advantageously 80% to 90% solids, such as 85% solids. In some advantageous embodiments the uncured composition 22 will have a specific gravity greater than 2.0 grams/cc and advantageously a specific gravity of about 2.8 grams/cc.
[0034] The mixed composition 22 is applied to the support 14 and worked through open areas between the support elements 16 to contact the baffle surface 10 . The composition 22 will start curing when mixed so the time to apply the mixed composition 22 to the support 14 and surface 10 is limited.
[0035] The following examples are included for purposes of illustration so that the disclosure may be more readily understood and are in no way intended to limit the scope of the disclosure unless otherwise specifically indicated.
[0036] The following compositions 1 through 4 were prepared as shown in the following Table. All amounts are parts by weight.
[0000]
Component
1
2
3
4
Part A
colloidal silica 1
30
22
22
20
Part B
alumina powder 2
60
60
40
60
metal powder 3
5
10
0
10
silicon carbide powder
5
0
0
0
ceramic beads
20
20
20
20
accicular shaped alumina powder
0
0
10
0
metal oxides
0.5-1
0
0
0
Part C
magnesium oxide 4
0
.1
0
0
sodium dihydrogen
0
0
0.5
0
orthophosphate 5
sodium silica fluoride 6
0
0
0
0.3
sodium borate 7
0
0.2
0
0.2
total
121
112.3
92.8
110.2
open time (Minutes)
>55
10-15
30-45
10-20
1 dispersion of 40 wt % colloidal silica (20-80 nm) in fluid
2 Alumina powder, 325 mesh
3 stainless steel, 325 mesh
4 magnesium oxide powder, 98% purity
5 sodium dihydrogen orthophosphate, 98% purity
6 sodium silica fluoride, 98% purity
7 sodium borate, 99% purity
[0037] Open time is the elapsed time between mixing of the composition parts and curing of the mixed composition to the point it can not be readily applied to a reinforcing substrate and surface.
[0038] The following compositions were prepared as shown in the following Table. All amounts are weight %.
[0000]
Composition (wt %)
Ratings
Colloidal
K
Alumina
Metal
Ceramic
Na
Mg
Binder
Sample
silica 1
silicate 2
powder 3
powder 4
beads 5
borate 6
oxide 7
% 8
P/B 9
R 10
Crack
5
7.92
13.68
45.00
15.00
18.13
0.18
0.09
21.6
3.6
3
0
6
3.70
12.89
54.56
10.44
18.13
0.18
0.09
16.6
5.0
0
3
7
10.00
13.31
53.29
5.00
18.13
0.18
0.09
23.3
3.3
5
0
8
3.70
12.89
54.56
10.44
18.13
0.18
0.09
16.6
5.0
3
5
9
10.00
19.00
45.00
7.60
18.13
0.18
0.09
29.0
2.4
5
5
10
3.42
13.36
49.82
15.00
18.13
0.18
0.09
16.8
4.9
3
5
11
3.70
12.89
54.56
10.44
18.13
0.18
0.09
16.6
5.0
3
5
12
10.00
5.00
51.60
15.00
18.13
0.18
0.09
15.0
5.7
3
3
13
0.00
19.00
47.60
15.00
18.13
0.18
0.09
19.0
4.3
0
5
14
6.59
5.00
57.54
12.47
18.13
0.18
0.09
11.6
7.6
0
0
15
0.00
16.60
60.00
5.00
18.13
0.18
0.09
16.6
5.0
0
0
16
10.00
5.00
60.00
6.60
18.13
0.18
0.09
15.0
5.7
0
5
17
9.50
13.58
48.75
9.78
18.13
0.18
0.09
23.1
3.3
5
0
18
5.10
19.00
52.50
5.00
18.13
0.18
0.09
24.1
3.2
3
5
19
0.57
6.03
60.00
15.00
18.13
0.18
0.09
6.6
14.1
0
0
20
5.32
11.14
59.72
5.42
18.13
0.18
0.09
16.5
5.1
0
5
21
5.10
19.00
52.50
5.00
18.13
0.18
0.09
24.1
3.2
5
3
22
0.00
19.00
52.58
10.02
18.13
0.18
0.09
19.0
4.3
0
5
23
3.70
12.89
54.56
10.44
18.13
0.18
0.09
16.6
5.0
3
5
24
10.00
13.31
53.29
5.00
18.13
0.18
0.09
23.3
3.3
5
0
25
4.75
14.25
52.23
18.99
9.5
0.19
0.09
20.0
4.0
5
0
26
4.8
14.25
52.2
9.5
19.0
0.2
0.09
19
4.25
1 dispersion of 40 wt % colloidal silica (20-80 nm) in fluid (Bindzil 40/170 available from Akzo Nobel).
2 potassium silicate (Ricasil K-40 available from Ricasil Industries; Kasil-6 available from PQ Corp.).
3 Alumina powder, 325 mesh (Tabular alumina T60 available from Almatis).
4 stainless steel, 325 mesh (Duramet available from Washington Mills Electro Minerals Corp).
5 Sintered alumina ceramic beads (Sintered Alumina Ceramic available from CoorsTek).
6 sodium borate, 99% purity.
7 magnesium oxide powder, 98% purity.
8 Binder % is weight of (colloidal silica + K silicate)/weight of composition × 100.
9 P/B is weight of (all fillers + all crosslinkers)/ weight of (colloidal silica + K silicate)
10 Rheology test results.
Rating Standard:
[0039] Rheology The mixed putty is applied on a metal panel at a 5 mm thickness to assess the sag resistance, wetting and holding power. A rating of 5 is given to a composition which is creamy, easy to apply and wets properly on metal but does not sag. A rating of 3 is given to a composition that is thicker and beyond a paste consistency. A rating of 0 is given to a composition that readily crumbles and does not properly hold to the matrix.
[0040] Cracking A composition is applied at 3 mm thickness to a 2 inch aluminum disc and allowed to cure. After full cure, if there were no visible crack then rating is 5; if there were one or two cracks then rating is 3; and if the material has more than two cracks then rating is 0.
[0000]
5
3
0
Rheology
Comparable to CTR, non-
thicker but can be
Highly thick
sag (runny), easy mix
mixed
or not mixed
[0000]
5
3
0
Cracking
No Crack
Moderate cracking
High cracking
[0041] A four inch by four inch stainless steel panel was obtained. A reinforcing support comprising a plurality of perpendicularly arranged 1.8 mm diameter wires forming 12.8 mm squares was spot welded to a surface of the panel surface. The composition of sample 26 was disposed over the attached reinforcing support and panel surface to form a 3 to 6 mm thick layer and wear surface. The disposed composition was cured on the panel by exposure to ambient temperatures for 4 to 24 hours, followed by heating to 150° C. for 1 hour before fully curing for 12 hrs @ 800° C. The cured composition was hard to the touch and had a grey appearance. The cured composition had the following properties.
[0000]
weight loss after 800° C. for 24 hours
0%
Rockwell hardness (ASTM D-785)
35 HRA
compressive strength (ASTM D-695)
41 MPa (@ 25° C.)
compressive strength (ASTM D-695)
65 MPa (@ 250° C.)
compressive strength (ASTM D-695)
80 MPa (@ 586° C.)
Taber abrasion H18-1000 cycles
0%
(firing sample to 400° C.)
Taber abrasion CS-65 (WC wheel,
0%
firing sample to 400° C.)
[0042] Falling drop Impact resistance was tested as per ASTM D-2463 on cured examples of sample 26. The 4-lb hammer was dropped from 160 inch height on the coating w. metal reinforcement mesh prepared as described in line 38-44. The coating remain intact after five drops sustaining impact of 160 in-lbs of force. The wear surface and none of the cured composition had broken away from the plate.
[0043] Falling drop Impact resistance was tested as per ASTM D-2463 on a four inch by four inch stainless steel panel containing fully cured 3 to 6 mm thick layer of the composition of sample 26 with no reinforcing support. The comparative test panel without any reinforcement mesh failed only after one drop and cured composition shattered and came off the metal substrate.
[0044] The combination of reinforcing support and cured composition provided an impact resistant wear coating that is believed to be suitable for use with coal tip burners. The test panel with cured composition alone was substantially more fragile and not suited for use with coal tip burners.
[0045] Compositions comprising potassium silicate were surprisingly found to achieve a coating hardness suitable for use as a coal tip burner coating after drying at room temperature and without heat curing at temperatures above room temperature. Heat curing the potassium silicate comprising compositions above room temperature further increased the cured hardness. The same compositions without potassium silicate did not achieve the same coating hardness with only room temperature drying.
[0046] From the above variation of potassium silicate and colloidal silica amount, it was observed that the amount of colloidal silica has a direct impact on the flow property and the crack formation after drying. The higher binder amount (i.e lower P/B value) shows optimum performance with material rheology and reduced crack formation. Sample numbers 8, 9, 10, 11 and 21 was found to provide a very desirable balance of both the characteristics (rheology and reduced crack formation).
[0047] While preferred embodiments have been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the disclosure herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and scope of the present disclosure.
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A wear resistant substrate including a metal substrate having a surface, a reinforcing support attached to the surface and cured reaction products of an inorganic curable composition disposed over and through the reinforcing support and bonded to the surface. Also a method of enhancing the wear resistance of a metal surface by attaching a reinforcing support to the surface; disposing an inorganic curable composition over and through the reinforcing support and into contact with the surface; and curing the composition.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a water saver valve. More particularly, the present invention relates to a water saver valve for water consumption devices such as toilets and the like which prevents excess water usage even in the event of a water consumption device failure.
2. Prior Art
The provision of a water saver valve coupled to the inlet of a toilet tank is known in the art. Klaus, U.S. Pat. No. 4,964,421, discloses one such device. The Klaus device, however, utilizes a complex and expensive hour glass shaped chamber in combination with a gate which is activated by a pilot valve sensing pressure across a flow restriction. The Klaus device also utilizes a variable restrictor which requires an external tool for fine adjustment.
There remains a need for a water saver valve which is simple in its design, relatively inexpensive, less complex and one which is less likely to become stuck or fail from a lack of use.
SUMMARY OF THE INVENTION
The present invention provides such a water saver valve. In its simplest form, the present invention includes an intensifier piston chamber including a reciprocating piston movable by fluid pressure between a first position and a second position, a shutoff spool chamber juxtaposed to said piston chamber, a control spool chamber, an inlet having a supply orifice connected to said shutoff spool chamber and having a control spool supply line connected to said control spool chamber, an outlet having an outlet orifice connected to said shutoff spool chamber and having a pilot line connected to said control spool chamber, a piston first position supply line connected from a first side of said piston to said control spool chamber and a piston second position supply line connected from a second side of said piston to said control spool chamber and a drain tank line port. A shutoff spool is positioned in said shutoff spool chamber said shutoff spool movable between a first open position and a second closed position, said shutoff spool being biased to said first open position and movable to said second closed position by direct physical contact by said piston against said shutoff spool. A control spool is positioned in said control spool chamber to control movement of said intensifier piston.
Preferably, the shutoff spool is spring biased to said first open position.
Preferably, the control spool is movable from a first position to a second position by fluid pressure from said pilot line and movable from said second position to said first position by fluid pressure from said control spool supply line, said control spool supply line providing a fluid connection to said piston first position supply line when said control spool is in said first position causing movement of said piston in a first direction, said control spool supply line providing a fluid connection to said piston second position supply line when said control spool is in said second position causing movement of said piston in a second direction and said piston first position supply line being connected through said control spool to said drain line when said control spool is in said second position.
Preferably, the control spool supply line provides said fluid connection to said piston first position supply line and to said piston second position supply line through a control spool passageway in said control spool.
Preferably, the control spool has an outward end which extends at least partially out of a housing containing said control spool chamber and control spool.
Preferably, the control spool is also movable from a first position to a second position by manually depressing said outward end of said control spool.
The supply orifice preferably has a diameter of approximately 0.125 inches. The outlet orifice preferably has an internal diameter of between 0.125 inches and 0.140 inches. The pilot line preferably has an internal diameter between 0.062 inches and 0.078 inches.
Preferably, the control spool supply line and said pilot line provide equal fluid pressure to opposite ends of said control spool when fluid needs of a water consumption device connected to the outlet is satisfied. Preferably, the pilot line provides fluid pressure to a larger surface area of said control spool than is provide by said control spool supply line thus biasing said control spool to said second control spool position when equal fluid pressure is provided to opposite ends of said control spool.
Preferably, the piston and said control spool are caused to move from said first position to said second position and back to said first position every time fluid is caused to flow from said inlet to said outlet thus reducing the possibility that said moving components might become frozen in place because of infrequent use.
Preferably, the water saver valve provides an automatic reset function whereby said piston, said shutoff spool and said control spool are each initially biased in a first position which allows fluid to flow unrestricted from said inlet line to said outlet line for a period of time required for said piston to move by fluid pressure to said second position, after fluid needs of a water consumption device are satisfied fluid pressure then causing said control spool to move to said second position and causing said piston to move back to said first position.
Preferably, the control spool is biased to said first position by fluid pressure when fluid flow is passing from the inlet to the outlet.
Preferably, the control spool is biased to said first position by fluid pressure when said shutoff spool is in a said second closed position.
Preferably, the control spool is biased to said second position by fluid pressure when a fluid flow cannot pass from said inlet to said outlet because fluid needs of a water consumption device connected to said outlet have been satisfied.
Preferably, the control spool is biased to said second position by providing a control spool with a larger surface area subjected to fluid pressure from said pilot line and a smaller surface area subjected to fluid pressure from said control spool supply line. Preferably, the larger surface area is approximately 1.3 times as large as said smaller surface area.
Preferably, the water saver valve provides a device failure function whereby if flow continues to enter said inlet for a period of time longer than that required for said piston to move from said first position to said second position said shutoff spool will be pushed to its second closed position, said piston and said shutoff spool will remain in said second position until said control spool is manually reset or until fluid ceases to enter said inlet.
Preferably, said inlet is connected to a water supply line and said outlet is connected to an inlet to a water consumption device such as a toilet, washing machine, water heater or the like.
Preferably, the intensifier piston chamber and said shutoff spool chamber are provided in a first housing and said control spool chamber is provided in a second housing hydraulically connected to said first housing.
Alternatively, the intensifier piston chamber, said shutoff pool chamber and said control spool chamber are provided in a single housing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a hydraulic schematic diagram of the present invention.
FIG. 2A is a cross-sectional view of the present invention with the piston, control spool and shutoff valve each in a first position.
FIG. 2B is a cross-sectional view of the present invention with the piston and the shutoff valve in a first position and the control spool in a second position.
FIG. 2C is a cross-sectional view of the present invention with the piston and the shutoff valve in a second position and the control spool in a first position.
FIG. 3 is a cross-sectional view of the present invention with the control spool shown in a first housing and the piston and the shutoff valve in a second housing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the Figures, the following is a listing of component names and reference numbers as utilized in the following descriptions.
Device inlet ( 1 ) Supply orifice ( 2 ) Shutoff spool chamber ( 3 ) Outlet diversion ( 4 ) Outlet orifice ( 5 ) Outlet port ( 6 ) Inlet diversion ( 7 ) Supply port of the control spool ( 8 ) Control spool, 2 piece ( 9 ) Supply port of the intensifier piston extend chamber ( 10 ) Intensifier piston extend chamber ( 11 ) Reciprocating piston ( 12 ) Intensifier piston retract chamber ( 13 ) Shutoff spool ( 14 ) Shutoff spool orifice ( 15 ) Supply port of the intensifier piston retract chamber ( 16 ) Control spool pilot orifice ( 17 ) Control spool pilot port ( 18 ) Control spool passageway ( 19 ) Tank port of the control spool ( 20 ) Drain tank line ( 21 ) Drain tank ( 22 ) Shutoff spool biasing spring ( 23 ) Manual reset button of the control spool ( 24 ) Shutoff spool seat ( 25 ) Control spool supply orifice ( 26 ) Control spool screen ( 27 ) Exhaust port ( 28 ) Control spool chamber ( 29 ) Control spool pilot line (PL 1 ) Control spool supply line (SL 1 ) Piston first position supply line (SL 1 A) Piston second position supply line (SL 1 B)
The present invention is designed to operate in three different functional modes which will be described in detail below as an Operational Mode with Auto Reset Function; an Operational Mode with Outlet Device Failure and No Reset; and a Manual Reset of the Valve.
Operational Mode with Auto Reset Function
In this mode, water flows into the device inlet ( 1 ) at a specified minimum of 25 dynamic psi diverting into the 0.125″ supply orifice ( 2 ) flowing through the shutoff spool chamber ( 3 ), into the outlet diversion ( 4 ) through the 0.125″–0.140″ outlet orifice ( 5 ) to the device connected to the outlet port ( 6 ). The device connected to the outlet port ( 6 ) will begin to be filled with water through the described circuit.
As the device connected to the outlet port ( 6 ) is being filled with water, water also flows through the device inlet ( 1 ) to the inlet diversion ( 7 ) through the control spool supply orifice ( 26 ) through control spool supply line (SL 1 ) then into the supply port of the control spool ( 8 ) through the 0.011″ perforated control spool screen ( 27 ), which filters debris, creating and maintaining pressure to allow biasing of the control spool then through the control spool passageway ( 19 ) through piston first position supply line (SL 1 A) diverting the flow of water through the supply port of the intensifier piston extend chamber ( 10 ) to the intensifier piston extend chamber ( 11 ) allowing pressure and volume to build on the reciprocating piston ( 12 ) causing movement of the reciprocating piston ( 12 ) to move into the direction of the intensifier piston retract chamber ( 13 ) forcing water to be emptied from the intensifier piston retract chamber ( 13 ) through the shutoff spool orifice ( 15 ) located in the shutoff spool( 14 ).
The shutoff spool ( 14 ) will be held in the open position by the shutoff spool biasing spring ( 23 ) allowing water to flow through the shutoff spool chamber ( 3 ) to the outlet diversion ( 4 ) through the outlet orifice ( 5 ) which upon diverging and converging of fluid at the outlet orifice ( 5 ), a venturi effect is created which causes a vacuum or a minimal pressure that will assist the biasing of the control spool then fluid flows to the device connected to the outlet port ( 6 ). Thus the reciprocating piston ( 12 ) has begun its timing function directly related to the volume of the water flow.
Upon reaching the capacity satisfaction of the device located at the outlet port ( 6 ), the auto reset function of the circuit shall occur as follows:
Water flows into the device inlet ( 1 ) diverting into the supply orifice ( 2 ) flowing through the shutoff spool chamber ( 3 ), into the outlet diversion ( 4 ) and is blocked from entering the outlet orifice ( 5 ) because the device connected to the outlet port ( 6 ) has been satisfied and will block water flow. The water at the outlet diversion ( 4 ) will be forced to go through the 0.0625″ control spool pilot orifice ( 17 ) through control spool pilot line (PL 1 ) causing pressure to be present at the control spool pilot port ( 18 ) to overcome the biasing of the control spool, creating a force to move the control spool ( 9 ) which is shown as a two piece design, the upper piston has an area of 0.41 sq./in. and the lower piston has an area of 0.31 sq./in., which could be manufactured as one piece, then allowing trapped air to exit through the exhaust port ( 28 ). A diversion of water will occur from the device inlet ( 1 ) to the inlet diversion ( 7 ) through the control spool supply orifice ( 26 ) through control spool supply line (SL 1 ) to the supply port of the control spool ( 8 ) through the control spool passageway ( 19 ) through piston second position supply line (SL 1 B) to flow to the supply port of the intensifier piston retract chamber ( 16 ) causing water to be supplied to the intensifier piston retract chamber ( 13 ) causing pressure to be created at the intensifier piston retract chamber ( 13 ) causing movement of the reciprocating piston ( 12 ) to move in the direction of the intensifier piston extend chamber ( 11 ). The pressure created at the intensifier piston extend chamber ( 11 ) will be forced to flow through the supply port of the intensifier piston extend chamber ( 10 ) through piston first position supply line (SL 1 A) through the control spool ( 9 ) to the tank port of the control spool ( 20 ) connected to the drain tank line ( 21 ) emptying into the drain tank ( 22 ).
The foregoing actions allow the total reset of the valve. The reset will be held in position due to the supply pressure being present and the device at the outlet port ( 6 ) being satisfied.
The Auto Reset Function described in this section is the normal operational mode of the present invention. Each time a user flushes a toilet (or utilizes a predetermined amount of water from any water consumption device), the actions described above will occur. Because the reciprocating piston ( 12 ) and control spool ( 9 ) are put into motion on a regular basis, there is less likelihood that these components will become frozen in place because of long periods of remaining in a stationary position.
Operational Mode with Outlet Device Failure and No Reset
When failure of the water consumption device occurs, the following actions occur with the water saver valve of the present invention. Water flows into the device inlet ( 1 ) diverting into the supply orifice ( 2 ) flowing through the shutoff spool chamber ( 3 ), into the outlet diversion ( 4 ) through the outlet orifice ( 5 ) to the device connected to the outlet port ( 6 ). The water consumption device connected to the outlet port ( 6 ) will begin to be filled with water through the described circuit. As the device connected to the outlet port ( 6 ) is being filled with water, water also flows through the device inlet ( 1 ) to the inlet diversion ( 7 ) through the control spool supply orifice ( 26 ) into the supply port of the control spool ( 8 ) creating and maintaining pressure to allow biasing of the control spool then through the control spool passageway ( 19 ) diverting the flow of water through the supply port of the intensifier piston extend chamber ( 10 ) to the intensifier piston extend chamber ( 11 ) allowing pressure and volume to build on the reciprocating piston ( 12 ) causing movement of the reciprocating piston ( 12 ) to move into the direction of the intensifier piston retract chamber ( 13 ) forcing water to be emptied from the intensifier piston retract chamber ( 13 ) through the shutoff spool orifice ( 15 ) located in the shutoff spool ( 14 ). The shutoff spool ( 14 ) will be held in the open position by the shutoff spool biasing spring ( 23 ) allowing water to flow through the shutoff spool chamber ( 3 ) to the outlet diversion ( 4 ) through the outlet orifice ( 5 ) to the device connected to the outlet port ( 6 ). Thus, the reciprocating piston ( 12 ) has begun its timing function directly related to the volume of the water flow.
Upon no capacity satisfaction of the device located at the outlet port ( 6 ) and after the volume timing function has been reached, the reciprocating piston ( 12 ), which was moving in the direction of the shutoff spool ( 14 ), will directly contact the shutoff spool ( 14 ) and begin to move the shutoff spool ( 14 ) in the direction of the shutoff spool biasing spring ( 23 ). Supply pressure is present on the reciprocating piston ( 12 ) in the intensifier piston extend chamber ( 11 ) side of the reciprocating piston ( 12 ) creating a force to overcome the pressure of the shutoff spool biasing spring ( 23 ) causing the shutoff spool ( 14 ) to contact the shutoff spool seat ( 25 ) stopping the flow of water from the device inlet ( 1 ) flowing through the supply orifice ( 2 ) and stopped at the shutoff spool ( 14 ) which is now contacting the shutoff spool seat ( 25 ). Allowing the flow of water to be stopped to the shutoff spool chamber ( 3 ), outlet diversion ( 4 ), control spool pilot orifice ( 17 ), outlet orifice ( 5 ) and the outlet port ( 6 ) prevents water from going through to the device which has failed attached to the outlet port ( 6 ).
Supply pressure will hold the shutoff spool ( 14 ) in place due to the supply pressure being present at the device inlet ( 1 ) to the inlet diversion ( 7 ) through the control spool supply orifice ( 26 ) through control spool supply line (SL 1 ) into the supply port of the control spool ( 8 ) creating and maintaining pressure to allow biasing of the control spool then through the control spool passageway ( 19 ) through piston first position supply line (SL 1 A) diverting the flow of water through the supply port of the intensifier piston extend chamber ( 10 ) to the intensifier piston extend chamber ( 11 ) applied to the reciprocating piston ( 12 ).
The valve is now in the shutoff mode due to a device connected to the outlet port ( 6 ) failing to stop consuming water at the predetermined consumption level. Simply put water which flows to the “running toilet” or other failed water consumption device is shutoff and remains shutoff until the present invention is manually reset in the manner described below.
Manual Reset of the Valve
Upon the failure of a device connected to the outlet port ( 6 ), a manual reset is required after correcting the failure problem.
A manual reset is accomplished as follows: Depress and hold the manual reset button ( 24 ) which will move the control spool ( 9 ) allowing a diversion of water to occur from the device inlet ( 1 ) to the inlet diversion ( 7 ) through the control spool supply orifice ( 26 ) through control spool supply line (SL 1 ) to the supply port of the control spool ( 8 ) then through the control spool passageway ( 19 ) diverting the flow of water through piston second position supply line (SL 1 B) to flow to the supply port of the intensifier piston retract chamber ( 16 ) causing water to be supplied to the intensifier piston retract chamber ( 13 ) causing pressure to be created at the intensifier piston retract chamber ( 13 ) causing movement of the reciprocating piston ( 12 ) to move in the direction of the intensifier piston extend chamber ( 11 ).
The pressure created at the intensifier piston extend chamber ( 11 ) will be forced to flow through the supply port of the intensifier piston extend chamber ( 10 ) through piston first position supply line (SL 1 A) through the control spool( 9 ) to the tank port of the control spool ( 20 ) connected to the drain tank line ( 21 ) emptying into the drain tank ( 22 ). The reciprocating piston ( 12 ) will be in the original home or first position and the shutoff spool biasing spring ( 23 ) will extend the shutoff spool ( 14 ) to the reset (first) position off of the shutoff spool seat ( 25 ) which will then allow water to flow into the device inlet ( 1 ) diverting into the supply orifice ( 2 ) flowing through the shutoff spool chamber ( 3 ), into the outlet diversion ( 4 ) through the outlet orifice ( 5 ) to the device connected to the outlet port ( 6 ) allowing the device connected to the outlet port ( 6 ) to be filled with water. Release of the reset button ( 24 ) allows the pressure to reset the control spool ( 9 ) to the biased first position.
The three operational modes have now been described. What may not be apparent to those skilled in the art is that for the present invention to operate properly, some of the dimensions of the various ports, orifices, passageways and other components of the present invention are quite critical and have been discovered only after extensive experimentation. While the present invention is intended for use for a variety of different water consumption devices, the detailed description and the dimensions provided herein have been designed specifically for use of the present invention with a standard toilet.
The invention having been disclosed in connection with the foregoing variations and examples, additional variations will now be apparent to persons skilled in the art. The invention is not intended to be limited to the variations specifically mentioned and accordingly, reference should be made to the appended claims rather than the foregoing discussion of preferred examples, to assess the scope of the invention in which exclusive rights are claimed.
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The present invention relates to a valve designed to be in series with a toilet water supply line and the inlet of a toilet tank so that water which is flowing into the tank must flow through the valve. The valve includes a shutoff spool that is actuated by an intensifier piston. When the water volume exceeds the tank capacity due to a failure of the float valve in the toilet supply tank, the shutoff spool is actuated by the intensifier piston allowing flow to the toilet to be blocked.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 61/468,968, filed on Mar. 29, 2011. The entire disclosure of the above application is incorporated herein by reference.
FIELD
[0002] The present disclosure relates to a door for controlling temperature and airflow distribution in a heating, ventilation, and air conditioning system in a vehicle.
BACKGROUND
[0003] This section provides background information related to the present disclosure which is not necessarily prior art.
[0004] Heating, venting, and air conditioning (HVAC) systems in a vehicle typically include a blower, an evaporator, a heater core, a temperature door, and an airflow door. The blower blows air through the evaporator and the heater core. The temperature door controls the temperature of airflow exiting the HVAC system by adjusting airflow through the evaporator and/or the heater core. The airflow door controls the distribution of airflow exiting the HVAC system by adjusting airflow to various outlets.
[0005] HVAC systems that include two doors to control temperature and airflow distribution typically include a linkage that couples the two doors. These HVAC systems may be difficult to package in a vehicle due to space constraints, such as those associated with auxiliary HVAC systems. In addition, these systems include a large number of parts, increasing complexity and cost.
SUMMARY
[0006] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
[0007] A heating, venting, and air conditioning (HVAC) system for a vehicle according to the principles of the present disclosure includes a blower, an evaporator, a heater core, and a single door. The blower is operable to blow air. The evaporator is positioned downstream from the blower and is operable to cool air flowing through the evaporator. The heater core is positioned downstream from the evaporator and is operable to heat air flowing through the heater core. The single door is positioned downstream from the heater core and is rotatable to control airflow through the heater core and to direct airflow to at least one of a first outlet and a second outlet.
[0008] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
[0009] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
[0010] FIG. 1 is a section view of a heating, venting, and air conditioning (HVAC) system including a first door for controlling temperature and airflow distribution according to the principles of the present disclosure;
[0011] FIG. 2 is an isometric view of the door shown in FIG. 1 ;
[0012] FIG. 3 is a section view of the HVAC system of FIG. 1 illustrating the first door adjusted to a first position;
[0013] FIG. 4 is a section view of the HVAC system of FIG. 1 illustrating the first door adjusted to a second position;
[0014] FIG. 5 is a section view of the HVAC system of FIG. 1 illustrating the first door adjusted to a third position;
[0015] FIG. 6 is a planar view of a second door for controlling temperature and airflow distribution of an HVAC system according to the principles of the present disclosure;
[0016] FIG. 7 is a planar view of the second door in the direction of arrows 7 shown in FIG. 6 ;
[0017] FIG. 8 is a planar view of the second door in the direction of arrows 8 shown in FIG. 6 ;
[0018] FIG. 9 is a section view of the second door taken along a line extending between arrows 9 shown in FIG. 7 and in the direction of the arrows 9 ;
[0019] FIG. 10 is the section view of FIG. 9 illustrating the second door adjusted to the first position;
[0020] FIG. 11 is the section view of FIG. 9 illustrating the second door adjusted to the second position; and
[0021] FIG. 12 is the section view of FIG. 9 illustrating the second door adjusted to the third position; and
[0022] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
DETAILED DESCRIPTION
[0023] Example embodiments will now be described more fully with reference to the accompanying drawings.
[0024] Referring to FIG. 1 , a heating, ventilation, and air conditioning (HVAC) system 10 includes a blower 12 , an evaporator 14 , a heater core 16 , and a door 18 . The blower 12 blows air through the evaporator 14 and the heater core 16 . The evaporator 14 cools air flowing through the evaporator 14 . The heater core 16 heats air flowing through the heater core 16 . The door 18 controls the temperature and distribution of airflow exiting the HVAC system 10 . The HVAC system 10 is an auxiliary or rear HVAC system for a vehicle, however, the door 18 may be included in a primary or front HVAC system for a vehicle.
[0025] The door 18 controls the temperature by adjusting the amount of airflow through the heater core 16 . The door 18 controls the airflow distribution by adjusting the amount of airflow directed to an outlet 20 and an outlet 22 . The outlet 20 may be a face outlet and the outlet 22 may be a foot outlet. Alternatively, the outlet 20 may be the foot outlet and the outlet 22 may be the face outlet. Additionally, the heater core 16 may be positioned as shown in dashed lines. The location of the face and foot outlets may be independent from the position of the heater core 16 .
[0026] With additional reference to FIG. 2 , the door 18 includes a first portion 24 , a second portion 26 , and bosses 28 on opposite sides of the door 18 at the interface between the first portion 24 and the second portion 26 . Components of the door 18 may be integrally formed as a single unit or formed separately and joined together. The first portion 24 and the second portion 26 may be symmetric with respect to a rotational axis of the door 18 extending through the bosses 28 . To this end, the door 18 may be referred to as a dual door, as the first portion 24 and the second portion 26 may resemble opposite facing doors.
[0027] The first and second portions 24 , 26 include closed ends 30 and closed sides 32 defining an opening 34 extending through the door 18 . The closed ends 30 of the first and second portions 24 , 26 may have a round or dome shape. To this end, the door 18 may be referred to as a dual dome door. The closed sides 32 of the first and second portions 24 , 26 may have a flat pie shape. The opening 34 may extend between the closed ends 30 of the first and second portions 24 , 26 and between the closed sides 32 of the first and second portions 24 , 26 . The bosses 28 may not extend through the closed sides 32 to leave the opening 34 undivided between the first and second portions 24 , 26 . In this regard, the first and second portions 24 , 26 may be opposite-facing, pie-shaped portions defining a single hollow interior (i.e., the opening 34 ).
[0028] The first and second portions 24 , 26 may include ribs 36 and seals 38 . The ribs 36 may be formed on the inner surfaces of the closed ends 30 for structural support. The seals 38 may extend along the edges of the closed ends and sides 30 , 32 defining the opening 34 . When the door 18 hits a stop, such as an inner surface of a duct, the seals 38 may form a seal with the stop. The seals 38 may be rubber and the remainder of the door 18 may be plastic.
[0029] In operation, the door 18 may be rotated in the direction of arrows 40 to decrease the temperature of airflow exiting the HVAC system 10 and to direct more airflow to the outlet 20 and less airflow to the outlet 22 . The door 18 may be rotated using an actuator (not shown), such as a servomotor, coupled to the bosses 28 of the door 18 . Rotating the door 18 in the direction of the arrows 40 decreases the temperature of the exit airflow because less air is allowed to flow through the heater core 16 .
[0030] Conversely, the door 18 may be rotated in the direction of arrows 42 to increase the temperature of airflow exiting the HVAC system 10 and to direct more airflow to the outlet 22 and less airflow to the outlet 20 . Rotating the door 18 in the direction of the arrows 42 increases the temperature of the exit airflow because more air is allowed to flow through the heater core 16 . In this manner, the temperature and distribution of the exit airflow may be adjusted by simply rotating the door 18 .
[0031] Adjusting the temperature and distribution of the exit airflow using a single door eliminates the need to include multiple actuators driving multiple doors or complex linkages coupling a single actuator to multiple doors. In turn, the number of parts included in the HVAC system 10 and the amount of space required to package the HVAC system 10 in a vehicle are reduced relative to conventional HVAC systems. As a result, the cost and complexity of the HVAC system 10 are reduced relative to conventional HVAC systems.
[0032] Referring to FIGS. 3 through 6 , the door 18 may be adjusted to various positions to control the temperature and distribution of airflow exiting the HVAC system 10 . Each position may correspond to a mode of operating the HVAC system 10 . Although only three positions are shown, the door 18 may be adjusted to positions between the three positions, and the positions between the three positions may correspond to transitional phases between the modes.
[0033] FIG. 3 shows the door 18 adjusted to a first position. When the door 18 is in the first position, the door 18 prevents air from flowing through the heater core 16 or the outlet 22 and allows air to flow around the heater core 16 (i.e., directly from the evaporator 14 to the outlet 20 ) and through the outlet 20 . Arrows 44 represent the airflow through the HVAC system 10 when the door 18 is in the first position. Thus, the door 18 may be adjusted to the first position to provide maximum cooling and to direct all of the exit airflow to the outlet 20 .
[0034] Additionally, the HVAC system 10 may include a sliding door 46 . The sliding door 46 may be extended when the door 18 is in the first position, as shown in FIG. 3 , to prevent scrubbing. Scrubbing occurs when heated air between the heater core 16 and the door 18 flows back through the heater core 16 and to the outlet 20 . The sliding door 46 may be retracted when the door 18 is not in the first position to allow air to flow through the heater core 16 .
[0035] FIG. 4 shows the door 18 in a second position. When the door 18 is in the second position, the door 18 allows air to flow through the heater core 16 , around the heater core 16 , to the outlet 20 , and to the outlet 22 . Arrows 48 represent the airflow through the HVAC system 10 when the door 18 is in the second position. Thus, the door 18 may be adjusted to the second position to provide some heating and to direct the exit airflow to both of the outlets 20 , 22 . Air flowing through the heater core 16 (i.e., hot air) may flow to the outlet 22 , and air flowing around the heater core 16 (i.e., cold air) may flow to the outlet 20 . The hot and cold air may mix within the door 18 due to their crossing flow paths, and air may bypass the door 18 , which may eliminate temperature stratification.
[0036] FIG. 5 shows the door 18 in a third position. When the door 18 is in the third position, the door 18 allows air to flow through the heater core 16 and the outlet 22 and prevents air from flowing around the heater core 16 or through the outlet 20 . Arrows 50 represent the airflow through the HVAC system 10 when the door 18 is in the third position. Thus, the door 18 may be adjusted to the third position to provide maximum heating and to direct all of the exit airflow to the outlet 22 .
[0037] Referring to FIGS. 6 through 9 , a door 52 may be similar to the door 18 and include additional features to improve the mixing of hot and cold air. The door 52 includes closed sides 54 , 56 , partially opened sides 58 , 60 , closed ends 62 , 64 connecting the closed sides 54 , 56 , and bosses 66 projecting from the closed sides 54 , 56 and centered about a rotational axis of the door 52 . The door 52 may be symmetric with respect to a plane extending through the centers of the bosses 66 perpendicular to the closed sides 54 , 56 and the partially open sides 58 , 60 . In addition, the closed ends 62 , 64 may be dome shaped. To this end, the door 52 may be referred to as a dual dome door, as the symmetric portions of the door 52 may resemble two doors having dome-shaped ends.
[0038] FIG. 7 shows partition portions 68 , 70 defining openings 72 a through 82 a to allow air to flow through the partially open side 58 of the door 52 . When the door 52 is in the second position discussed above with reference to FIG. 4 , the openings 72 a , 76 a , and 80 a may allow cold air to flow out of the door 52 , and the openings 74 a , 78 a , and 82 a may allow hot air to flow into the door 52 . Although FIG. 7 delineates the partition portions 68 , 70 , the partition portions 68 , 70 may form a single partition extending between the closed ends 62 , 64 .
[0039] FIG. 8 shows the partition portions 68 , 70 defining openings 72 b through 82 b to allow air to flow through the partially open side 60 of the door 52 . When the door 52 is in the second position, the openings 72 b , 76 b , and 80 b may allow cold air to flow into the door 52 , and the openings 74 b , 78 b , and 82 b may allow hot air to flow out of the door 52 . Thus, the partition portions 68 , 70 may define hot air channels 74 , 78 , and 82 respectively extending between the openings 74 a , 78 a , and 82 a in the partially open side 58 and the openings 74 b , 78 b , and 82 b in the partially open side 60 . The partition portions 68 , 70 may also define cold air channels 72 , 76 , and 80 respectively extending between the openings 72 a , 76 a , and 80 a in the partially open side 58 and the openings 72 b , 76 b , and 80 b in the partially open side 60 .
[0040] FIG. 9 illustrates a mixing chamber 84 that extends between the closed sides 54 , 56 and connects the hot and cold air channels 72 through 82 , thereby improving the mixing between hot and cold airflow through the door 52 . As shown in FIG. 9 , the hot air channel 74 and the cold air channel 76 overlap, and the mixing chamber 84 extends between the overlapping portions of the channels 74 , 76 . Thus, hot air is allowed to flow from the hot air channel inlet 74 a , through the mixing chamber 84 , and to the cold air channel outlet 76 a . Conversely, cold air is allowed to flow from the cold air channel inlet 76 b , through the mixing chamber 84 , and to the hot air channel outlet 74 b . In this manner, cold air flows into the openings 72 b , 76 b , and 80 b , hot air flows into the openings 74 a , 78 a , and 82 a , the hot and cold air mixes in the mixing chamber 84 , and the mixed air flows to the openings 72 a , 74 b , 76 a , 78 b , 80 a , and 82 b.
[0041] Referring to FIGS. 10 through 12 , the door 52 may be used in place of the door 18 , and the door 52 may be adjusted to various positions to control the temperature and distribution of airflow exiting the HVAC system 10 . FIG. 10 shows the door 52 adjusted to the first position discussed above with reference to FIG. 3 . When the door 52 in the first position, the door 52 blocks hot airflow from the heater core 16 , blocks airflow to the outlet 22 , and allows cold air to flow directly from the evaporator 14 to the outlet 20 . Cold air may flow through the door 52 via any one of the channels 72 through 82 .
[0042] FIG. 11 shows the door 52 adjusted to the second position. When the door 52 is in the second position, the door 52 allows cold airflow from the evaporator 14 , hot airflow from the heater core 16 , and mixed airflow to both of the outlets 20 , 22 . Hot air enters the door 52 through the opening 74 a of the channel 74 (i.e., the hot air channel), and cold air enters the door 52 through the opening 76 b of the channel 76 (i.e., the cold air channel). The hot and cold air may mix in the mixing chamber 84 , and the mixed air may flow through the openings 74 b , 76 a . In this manner, the mixing chamber 84 improves the mixing of hot and cold air flowing through the door 52 .
[0043] FIG. 12 shows the door 52 adjusted to the third position discussed above with reference to FIG. 3 . When the door 52 in the third position, the door 52 blocks cold airflow from the evaporator 14 , blocks airflow to the outlet 20 , and allows hot air to flow from the heater core 16 to the outlet 22 . Hot air may flow through the door 52 via any one of the channels 72 through 82 .
[0044] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
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A heating, venting, and air conditioning (HVAC) system for a vehicle according to the principles of the present disclosure includes a blower, an evaporator, a heater core, and a single door. The blower is operable to blow air. The evaporator is positioned downstream from the blower and is operable to cool air flowing through the evaporator. The heater core is positioned downstream from the evaporator and is operable to heat air flowing through the heater core. The single door is positioned downstream from the heater core and is rotatable to control airflow through the heater core and to direct airflow to at least one of a first outlet and a second outlet.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention broadly relates to a printer sheet feed device for conveying recording paper sheets, and a sheet feed control method thereof, and, more particularly, to a printer sheet feed device for conveying recording sheets with high precision, and a sheet feed control method thereof.
2. Description of the Related Art
A serial-type printer is often used, which prints one line while a print head moves along a platen, and then conveys the recording sheet by an amount corresponding to one line in order to perform printing on the next line.
FIG. 4 illustrates a thermal transfer printer as an example of a serial-type printer. In the thermal transfer printer, a flat platen 2 is disposed at about the center of a printer frame 1 such that the print face of the platen 2 is disposed substantially vertically. A carriage shaft 3 is disposed at a location of the frame 1 forwardly of and below the platen 2 and parallel to the platen 2. A flange-shaped guide section 4 is formed at the front edge of the frame 1, while a carriage 5 is mounted to the carriage shaft 3 and the guide section 4 such that it can reciprocate along the carriage shaft 3 and the guide section 4. A thermal head 6, functioning as a print head, is mounted to an end of the carriage 5 which opposes the platen 2, and can come into contact with and move away from the platen 2 by means of a drive mechanism (not shown). A ribbon cassette (not shown) is removably mounted to the upper face of the carriage 2 in order to guide an ink ribbon between the thermal head 6 and the platen 2. A take-up bobbin for taking up the ink ribbon and a supply bobbin are disposed at the upper face of the carriage 5, and engage the ribbon cassette take-up reel and the supply reel, respectively.
A sheet insertion opening 9 is formed behind the platen 2 in order to feed the recording sheet (not shown) forwardly of the platen 2. Sheet feed rollers 10 are disposed at the sheet insertion opening 9 in order to convey the recording sheet between the thermal head 6 and the platen 2. Press-contacting rollers 11, rotatably disposed below the sheet feed rollers 10, press-contact their sheet feed rollers 10. Actually, a plurality of the press-contacting rollers 11 are provided at different locations where they press-contact the sheet feed rollers 10 in the direction of the circumference, in which at the start of conveying one recording sheet, only the press-contacting roller at the upstream side in the direction of conveyance of the recording sheet contributes to the conveyance of the recording sheet, while at the end of the conveyance of the recording sheet, only the press-contacting at the downstream side in the direction of the conveyance of the recording sheet contributes to the conveyance of the recording sheet.
A sheet feed gear 12, mounted coaxially with the sheet feed roller 10, projects out from a side face of the frame 1. A motor gear 15 driven by a sheet feed motor 14 which is a stepping motor is connected to the sheet feed gear 12 via a plurality of transmission gears 13. Driving the sheet feed motor 14 rotationally drives the sheet feed roller 10 via the motor gear 15, the transmission gears 13, and the sheet feed gear 12, whereby a recording sheet, nipped between the sheet feed rollers 10 and the press-contacting rollers 11, is conveyed.
FIG. 5 is a view showing the critical portion of a printer sheet feed device, wherein the sheet feed gear 12 is mounted to one end of a rotating shaft 16 and coaxially with the sheet feed roller 10. The sheet feed roller 10 is mounted to the rotating shaft 16, and is disposed such that the outer peripheral surface of the rotatable press-contacting roller can press contact it. The sheet feed motor 14, being a stepping motor, is disposed in the vicinity of the sheet feed gear 12 in order to rotationally drive the sheet feed roller 10. A motor gear 15 is affixed to an output shaft 17 of the sheet feed motor 14, with the motor gear 15 and the sheet feed gear 12 connected via a first transmission gear 13a, a second transmission gear 13b, and a third transmission gear 13c, which are formed at the outer peripheral portion. The first transmission gear 13a comprises a large gear section 18a and a small gear section 19a formed coaxially therewith. The second transmission gear 13b comprises a large gear section 18b and a small gear section 19b formed coaxially therewith. The third transmission gear 13c comprises a large gear section 18c and a small gear section 19c formed coaxially therewith. The motor gear 15 engages with the large gear section 18a of the first transmission gear 13a, the small gear section 19a of the first transmission gear 13a engages with the large gear section 18b of the second transmission gear 13b, the small gear section 19b of the second transmission gear 13b engages with the large gear section 18c of the third transmission gear 13c, and the small gear section 19c of the third transmission gear 13c engages with the sheet feed gear 12. The rotation of the sheet feed motor 14 is slowed down by these gear groups in order to transmit the rotation to the sheet feed gear 12.
When the sheet feed roller 10 is rotationally driven by an amount corresponding to one line feed pitch, the gear ratio of the motor gear 15 and the transmission gears 13a, 13b, and 13c is set such that the motor gear 15 and the transmission gears 13a, 13b, and 13c always stop at the rotation start position. For example, the gear ratio of the motor gear 15, the transmission gears 13a, 13b, and 13c, and the sheet feed gear 12 is set at 3:4:4:5. With the gear ratio set thus, the motor gear 15 and the transmission gears 13a, 13b, and 13c stop at the same position both before the start of line feeding (shown in FIG. 6A) and after the line feeding (shown in FIG. 6B), so that the problem related to the eccentricities of each of the gears 15, 13a, 13b, and 13c does not occur.
More specifically, when the number of teeth of the motor gear 15 is 14, the number of teeth of the large gear section 18a and that of the small gear 19a of the first transmission gear 13a are 42 and 14, respectively; the number of teeth of the large gear section 18b and that of the small gear section 19b of the second transmission gear 13b are 56 and 14, respectively; and the number of teeth of the large gear section 18c and that of the small gear 19c of the third transmission gear 13c are 56 and 14, respectively; and the number of teeth of the sheet feed gear is 70.
When the desired printing is performed using the serial-type printer, the paper sheet is inserted into the sheet insertion opening and the sheet feed motor 14 is driven to rotate the sheet feed roller 10 via the motor gear 15, the transmission gears 13a, 13b, and 13c, and the sheet feed gear 12, whereby the recording sheet is conveyed such that its printing start position is at the printing position. Thereafter, with the thermal head 6 kept press-contacted with the platen 2, each of the thermal elements of the thermal head 6 are driven on the basis of a desired drive signal, while the carriage 5 is driven, as a result of which the desired printing is performed on the recording sheet.
Upon completion of one line of printing, while the thermal head 6 is kept separated from the platen, the sheet feed motor 14 is driven by a predetermined number of steps to rotate the sheet feed roller 10 by a predetermined angle, whereby the recording sheet is conveyed by one line feed pitch. Here, as described above, the motor gear 15, and the transmission gears 13a, 13b, and 13c rotate an integral number of times and returns to its initial start position, so that the problem related to eccentricities or the like of the gears 15, 13a, 13b, and 13c does not occur, resulting in a very accurate amount of sheet feeding.
In the above-described printer sheet feed device, however, at the moment the back edge of the recording sheet passes between the sheet feed roller and the press-contacting roller 11 disposed upstream in the direction of conveyance of the recording sheet, the recording sheet is bent due to the rigidity of the sheet so that a force which pushes out the recording sheet forwardly acts on the recording sheet (the mechanical condition of the sheet feed mechanism with respect to the recording sheet is changed), causing the recording sheet to be conveyed by an amount greater than the specified line feed pitch (the difference being equal to the amount of backlash between the sheet feed gear 15 and the transmission gear 13c), even when the press-contacting roller 11 disposed downstream in the direction of conveyance of the recording sheet is conveying the recording sheet by the correct amount. Therefore, when line feeding is terminated at a location immediately following this location, the excess amount of line feeding being in correspondence with the amount of backlash is not eliminated, so that a space is produced between lines during printing immediately following the termination of the line feeding, resulting in reduced printing quality.
Excessive line feeding tends to be particularly noticeable when a relatively rigid recording paper sheet, such as a relatively thick postcard, is used.
Other mechanical condition changes, such as displacement of the back edge of the recording paper sheet from the edge of the sheet guide section, occur, may change the line feed pitch.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a printer sheet feed device and a sheet feed control method thereof, wherein in the case where a recording sheet is conveyed at a plurality of locations of the recording sheet, even when a mechanical condition changes during line feeding when the back edge of the recording sheet passes between an upstream roller in the direction of conveyance of the recording sheet, line feeding at a predetermined pitch is performed by means of another roller.
Another object of the present invention is to provide a printer sheet feed device and a sheet feed control method thereof, wherein in the case where a recording sheet is conveyed at either a single location or a plurality of locations of the recording sheet, when other mechanical conditions change, such as when the back edge of the recording sheet is displaced from the edge of the sheet guide section, sheet feeding is performed at a predetermined line feed pitch.
A further object of the present invention is to provide a control means for controlling the setting position of a recording sheet at the printing section when line feeding is started at a predetermined pitch, in accordance with the type of recording sheet.
A still further object of the present invention is to provide a control means for controlling the position of starting line feeding of a recording sheet at a predetermined pitch such that line feeding at a portion where a mechanical condition changes with respect to the recording sheet is performed at a position allowing continuation of line feeding by a predetermined amount from the moment the mechanical condition changes.
A still further object of the present invention is to make it possible to set a starting position of line feeding of the recording sheet by a predetermined pitch, such that line feeding at a portion where a mechanical condition changes with respect to the recording sheet is performed at a location allowing sheet feeding by a predetermined amount from the moment the mechanical condition changes, after which the sheet feed motor is driven under control by a predetermined number of drive steps which corresponds to a predetermined line feed pitch.
A still further object of the present invention is to make it possible to perform line feeding unaffected by changes in the mechanical condition of the sheet feed mechanism with respect to the recording sheet, even when line feeding at a constant pitch is performed, by terminating the line feeding after elimination of the extra line feeding being equivalent to the amount of backlash produced due to changes in the mechanical condition by constant continued line feed operations by more than a predetermined amount from the position the back edge of the recording sheet jumps due to its rigidity, that is from the position the mechanical condition of the sheet feed mechanism changes with respect to the recording sheet.
A still further object of the present invention is to make it possible to constantly perform line feeding by an equal amount by another conveying means, even when a first conveying means does not contribute to the conveyance of a recording sheet at a plurality of locations in the direction of conveyance of the recording sheet; and to make it possible to constantly perform line feeding by an equal amount in the same way, even when the mechanical condition changes, such as when the back edge of the recording sheet is displaced from the sheet guide section or the like.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an embodiment of a printer to which a sheet feed device of the present invention is applied.
FIG. 2 is a view showing the construction of the critical portion of the sheet feed mechanism of the printer of FIG. 1.
FIG. 3 is a diagram showing deviations from a predetermined pitch, when line feeding is to be performed at a constant pitch in the embodiment of FIG. 1.
FIG. 4 is a perspective view showing the construction of the critical portion of a conventional serial-type printer.
FIG. 5 is a perspective view showing the construction of the critical portion of a sheet feed mechanism of the conventional printer.
FIGS. 6A and 6B are diagrams for illustrating a drive power transmission system of the sheet feed mechanism of FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A description will now be given of the preferred embodiments of the printer sheet feed device and a sheet feed control method thereof, with reference to the drawings. Corresponding component parts to those of the conventional example are given the same reference numerals, and will not be described in detail below.
FIG. 1 is a block diagram showing the construction of the critical portion of a printer to which an embodiment of the sheet feed device in accordance with the present invention is applied. FIG. 2 is a view showing the construction of the critical portion of the sheet feed mechanism thereof. Although, as shown in FIG. 2, the illustrated printer of the present embodiment partly differs from the conventional printer in that recording paper sheets 20 are supplied from a sheet feed cassette 21 and separated one sheet at a time by a sheet feed roller 22 and conveyed between a platen 2 and a thermal head 6 by means of a sheet feed roller 10 and a press-contacting roller assembly 11, it is obvious that the printer may have the same construction as the aforementioned conventional printer. The press-contacting roller assembly 11 comprises two press-contacting rollers 11A and 11B which press contact two different locations of the sheet feed roller 10 in the direction of conveyance of the recording sheet, so that the recording sheet 20 is conveyed at a plurality of locations in the direction of conveyance of the recording sheet.
A sheet detector 23, being a photo-sensor which opposes the sheet feed roller 10, is disposed at a location downstream from the press-contacting roller assembly 11 in the direction of conveyance of the recording sheet 20, in order to detect whether or not a sheet is present and the front or back edge of the recording sheet 20. The sheet feed motor, the transmission mechanism, etc., are essentially the same as the conventional ones, so that they will not be described below.
In FIG. 1, a sheet selection means 25 is connected to a central processing unit (CPU) 24, being a control means which performs various control operations in the printer. When the sheet selection means 25 is used to set the type of recording sheet for printing, a signal of the set sheet type is input to the CPU 24. An image memory 26 is connected to the CPU 24, allowing input and output of printing information therebetween.
A sheet feed motor drive circuit 27 is connected to the CPU 24 in order to drive a sheet feed motor (not shown) which is a stepping motor for rotationally driving the sheet feed roller 10. A control signal from the CPU 24 causes the sheet feed motor drive circuit 27 to control the driving of the sheet feed motor. In addition, the CPU 24 is connected to a thermal head drive circuit 28 for supplying power to thermal elements (not shown) of the thermal head 6 on the basis of printing information, a carriage drive circuit 29 for driving a carriage drive motor (not shown) for causing reciprocating movement of a carriage carrying a thermal head 6, and a sheet detection circuit for inputting a sheet detection signal from the sheet detector 23.
As described above, variations in the sheet feed pitches occur at the moment the back edge of the recording sheet 20 passes between the sheet feed roller 10 and the upstream press-contacting roller 11A in the direction of conveyance of the recording sheet 20, when the recording sheet is conveyed at a predetermined pitch by the rotation of the sheet feed roller 10. The present applicant, however, found out that sheet feeding can be performed at the ordinary line feed pitch when line feeding is terminated after further rotationally driving the sheet feed motor, from the moment the back edge passes between the roller 10 and the roller 11A, by a greater number of steps than the predetermined number of steps in order to further convey the recording sheet between the sheet feed roller 10 and the press-contacting roller 11B. Sheet feeding can be performed at the ordinary line feed pitch because the extra amount of feeding (the amount being equal to the amount of backlash) produced upon passage between the rollers is eliminated by the additional rotation.
More specifically, when the sheet feed roller 10 is constantly rotated by a certain angle as a result of rotationally driving the sheet feed motor 14 by a predetermined number of driving steps, large variations in the sheet feeding occur at a particular location, as shown in FIG. 3. Referring to FIG. 3, the horizontal axis indicates the positions from an edge of the recording sheet 20, and the horizontal line represents the reference sheet feeding amount, above which the sheet feed amount is positive, and below which the sheet feed amount is negative. The recording sheet 20 is conveyed as a result of driving the sheet feed motor 14. The portions where line feeding of the recording sheet 20 is performed are denoted by A and B. When line feeding is performed first at A-1, line feeding of the recording sheet 20 is successively performed at A-2, A-3, etc. On the other hand, when line feeding is first performed at B-1, line feeding of the recording sheet 20 is successively performed at B-2, B-3, etc.
As can be seen from FIG. 3, when line feeding is successively performed from A-1, defined as the line feed start position, at an initial predetermined pitch, the back edge of the recording sheet 20, as described above, jumps, causing the sheet feed amount to deviate by a large amount in the positive direction at A-7, while the sheet feed amount at A-8 deviates by a large amount in the negative direction. On the other hand, when line feeding is performed from B-1, defined as the line feed start position, the line feed amount is always substantially on the horizontal line, so that the line feed amount at B-7 is not affected by jumping of the back edge of the recording sheet 20.
Accordingly, it is possible to minimize variations in the line feed pitches and control the line feeding to a constant amount by setting the initial line feed start position so that line feeding is not terminated, immediately after passage of the back edge of the recording sheet 20 between the sheet feed roller 10 and the press-contacting roller 11A. Since the recording sheet 20 used is a standard type sheet whose length is set, computation based on the printer characteristics is performed to permit line feeding of the recording sheet 20 under control such that it is performed by a predetermined amount from B-1 of FIG. 3 and successively performed therefrom by a constant amount at all times, which is a distinctive feature of the present invention.
In other words, since the sheet detector 23 and the printing section are separated from each other by a predetermined distance, after the front end of the recording sheet 20 conveyed by the sheet feed roller 10 has been detected by the sheet detector 23, the recording sheet 20 is set to the recording start position by rotationally driving the sheet feed motor 14 by the predetermined number of drive steps set at the CPU 24.
Here, the thermal head 6 has a resolution of 400 dpi, and a one line feed pitch of 9.906 mm, with the number of thermal element dots being 160. For a postcard used as the recording sheet, when the entire length of the postcard in the direction of vertical feeding is 148 mm, and printing can only be performed 3 mm from the top edge of the postcard due to mechanical limitations of the printer, itself, the printing start position is set at 3 mm from the top edge (front face) of the postcard. Here, when the postcard is selected as the recording sheet to be used by the sheet selection means 25, the CPU 24 controls each of the circuits 27 to 30 under the assumption that a postcard is being used as the recording sheet. From the time the sheet detector 23 detects the front edge of the postcard, the sheet feed motor 14 is rotationally driven by a predetermined number of steps in order to set the postcard between the platen 2 and the thermal head 6 such that the printing start position is 3 mm from its front edge. Repeating printing operations and ordinary 9.906-mm line feed operations from the setting causes the line feed operations to be terminated immediately after passage of the back edge of the postcard between the sheet feed roller 10 and the press-contacting roller 11A, so that the line feed pitch at this portion becomes large. This occurs in the present embodiment due to the distance between the thermal head 6 and the press-contact position of the sheet feed roller 10 and the press-contacting roller 11A. To overcome such a problem in the present invention, the reference position is set at 5 mm from the front edge of the postcard, and line feeding at the predetermined line feed pitch of 9.906 mm is performed from the reference position. In other words, printing is performed on a postcard, whose printing start position is set at 3 mm from the front edge, which is set at the printing section, using 34 thermal element dots, starting from those at the upper portion of the thermal head 6. Thereafter, the postcard is fed 2 mm to set the printing start position of the postcard at 5 mm from the top edge. With the printing start position set thus, control operations are performed so that ordinary printing and line feed operations are performed. Here, the line feed pitch is set four thermal element dots less than a printing range of one line in order to prevent the production of gaps between lines due to variations in the amount of line feeding. The problem regarding dark printing portions produced by overlapping between lines is overcome by print data processing.
According to the controlling method described above, a line feeding operation is terminated at a position immediately preceding the position of passage of the back edge of the postcard between the sheet feed roller 10 and the press-contacting roller 11a, and the back edge of the postcard passes between the sheet feed roller 10 and the press-contacting roller 11A immediately after the start of a next line feeding operation. Accordingly, after passage of the postcard between the rollers, line feeding is continued by means of the sheet feed roller 10 and the press-contacting roller 11B. Thereafter, the line feeding is terminated after further conveyance of the postcard by a predetermined amount, that is after rotationally driving the sheet feed motor 14 by the predetermined number of driving steps.
When more than 5 millimeters of non-printing space is to be left from the top edge of the postcard, the printing start position is initially set at 5 mm from the top edge and line feeding operations are performed at a constant pitch.
In the present embodiment, the number of drive steps of the sheet feed motor 14 is set to permit line feeding of 9.906 mm. At the moment the back edge of the postcard passes between the sheet feed roller 10 and the press-contacting roller 11A, the number of steps is set to more than two-thirds the number of steps permitting the 9.906-mm line feeding in order to perform line feeding of about 6 mm or more by means of the sheet feed roller 10 and the press-contacting roller 11B, thereby overcoming the problem of variations in the amount of line feed due to postcard jumping.
Although in the present embodiment of the invention, the settings of the printer are as described above, the line feed pitch, the type of recording 20 used, the printable recording sheet range, and the distance from the sheet feed roller and the press-contacting roller to the printing section vary with printers. Therefore, at the moment the back edge of the recording sheet 20 passes between the sheet feed roller 10 and the press-contacting roller 11, the printing start position of the recording sheet 20 to be subjected to ordinary line feeding is set to permit line feeding performed when the number of steps is more than two-thirds that of the set number of steps.
Although the present embodiment has been described for the case where the recording sheet is conveyed by being nipped between the sheet feed roller 10 and the press-contacting roller 11, jumping of the back edge of the recording sheet 20 does not necessarily occur only at the location where the back end of the recording sheet passes between the sheet feed roller 10 and the press-contacting roller 11. For example, jumping of the recording sheet may occur when it is displaced from the sheet guide section, which produces a location where the mechanical conditions of the sheet feed mechanism change. In such a case, it is obvious that the position for starting line feeding by a predetermined amount is set, taking into account such a location.
The present invention is not limited to the above-described preferred embodiments, so that various modifications can be made, when necessary. For example, in the present embodiment, two press-contacting rollers 11A and 11B were used as the rollers which press-contact the sheet feed roller 10 in the construction where the recording sheet is conveyed at a plurality of locations in the direction of conveyance of the recording sheet. However, in another construction, a roller at a recording sheet discharge side in the printer may be used to convey the recording sheet in the printer, with the sheet feed roller 10 press-contacted by only one press-contacting roller.
As can be understood from the foregoing description, according to the printer sheet feed control method of the present invention, the starting position of line feeding at an initial constant pitch is at the portion of the recording sheet where the mechanical conditions of the sheet feeding mechanism change with respect to the recording sheet, in accordance with the type of recording sheet used. Accordingly, sheet feeding can be performed at a fine line feeding pitch by simply controlling the line feeding such that it is performed at a constant pitch from the set position.
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The invention comprises a rotatable sheet feed roller; a rotatable press-contacting roller capable of press-contacting against an outer peripheral surface of the sheet feed roller; a sheet feed motor, being a stepping motor, for rotationally driving the sheet feed roller; and a transmission mechanism for transmitting the rotational power of the sheet feed motor to the sheet feed roller; wherein a line feed starting position of the recording sheet at a initial predetermined pitch is set to permit continuation of line feeding by a predetermined amount from a moment a mechanical condition with respect to the recording sheet changes during line feeding at a portion where the mechanical condition changes. The invention provides a printer that performs line feeding by a very accurate amount by line feeding at a constant pitch, even though a mechanical condition of the sheet feed mechanism changes.
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BACKGROUND OF THE INVENTION
[0001] 1. Technical Field of the Invention
[0002] The present invention relates to protein detection and purification. More specifically the invention relates to protein recognition sites. Even more specifically the invention relates to the modified peptide sequence from the Semliki Forest Virus (SFV) encoded non-structural protein suitable for use as recognition site for recombinant non-structural protease of SFV (hereafter “SFV protease site”), the nucleotide sequence and its variants that encode the recognition site. The invention also extends to the SFV protease recognition site fused into a polypeptide, inserted into a polypeptide sequence or placed between any peptide or protein tag and polypeptide sequence. The invention also extends to the methods for using the SFV protease site and corresponding enzyme.
[0003] 2. Background of the Invention
[0004] Site-specific proteolytic processing of expressed proteins is a widely used technical approach. This approach is used to remove unwanted sequences from expressed and purified recombinant proteins. Such unwanted sequences are often expression and/or purification tags; they can be peptide tags or protein tags. Peptide tags usually contain 4 to 20 amino acids, while protein tags usually have a molecule weight of some kdas. This approach is also used to process the multi-domain proteins into individual proteins both in vitro and in vivo (in living cells) conditions. Currently this approach is commonly used, but along with development of the methods of functional proteomics and methods for analysis of protein-protein interactions and protein functions directly in cell there is an increasing need for more precise, highly specific effective instruments.
[0005] Tagging (epitope tags, affinity tags, tags which stabilize the expressed protein or facilitate its correct folding in cells) is a widely used technology. Most of the proteins, currently used in biotechnology industry and for research purposes, are at some stage expressed as tagged fusion proteins since this allows using common and well established technologies for their detection, purification and concentration. However, because tags are usually immunogenic; because they can affect the protein structure and its ability to crystallize; because they can also mask the functional domains of recombinant protein and/or block specific and significant interactions with other proteins or cofactors, removal of the tags is an essential step before functional characterization of these recombinant proteins is possible. The tag removal is usually achieved by use of site specific processing with different proteases (thrombin, enterokinase, factor Xa, TEV (tobacco etch virus) protease and several others). Tag removal with proteases requires that the sequence encoding for protease recognition site has to be included in the expression vector. This sets certain limitations for protease recognition sites that can be used for this kind of vector type design:
sites should be relatively short; sites should be cleaved only by specific protease; sites should be cleaved with efficiency close to 100%.
[0009] Since all these properties can not always be combined inside of one vector, one usually has to choose between different sets of vectors depending on the purposes: Vectors with maximally efficient cleavage site provide rapid and highly efficient cleavage. With this kind of cleavage sites in the vector the amount of substrate processed by one unit of enzyme is as high as possible. Vectors with maximally precise cleavage site provide cleavage to take place as close as possible to the N- or C-terminus of recombinant proteins. Thus, depending on the nature of experimental and/or technological setup using one and same enzyme different cleavage sites can provide different results.
[0010] For use of the cleavage in in vivo conditions additional requirements will apply. The protease used for these experiments must be highly specific, must not cause injuries of the cells and the cleavage should be highly efficient. One application of the in vivo cleavage is to affect on the expression protein stability by removing degradation signals from the protein or to cleave protein in such a way that the N-terminal amino acid residue of cleaved protein will be recognized by protein degradation machinery and the cleaved protein will be degraded by N-end rule. For this kind of approach either inducible cell lines, conditionally expressing the protease or high efficiency cell co-transfection systems would be beneficial.
[0011] The high importance of these problems has led to commercialization of set of enzymes with site specific protease activity and corresponding vector plasmids. The enzymes have different (cellular, viral) origins and include thrombin, enterokinase, factor Xa, TEV (tobacco etch virus) protease and several others. The list of enzymes used for these purposes is growing and the information of the enzymatic and structural properties is expanding. The ideal combination of protease and its recognition sequence should fulfill the following criteria:
high efficiency at wide diapason of conditions (temperature, ionic condition, pH); high specificity for cleavage consensus, no secondary cleavages or side effects; possibility to make cleavages precisely at the end (N- and/or C-terminus) of recombinant protein; possibility to perform the reaction in vivo and in vitro; existence of easy to use and reversible inhibitors of protease activity.
[0017] In spite of the efforts to develop an ideal combination, so far none of the available protease/recognition site-combinations meets all the conditions of an ideal system as listed above. The present invention discloses a system that meets all these conditions and thereby introduces a novel, highly useful, precise and specific tool for site-specific proteolytic processing of proteins.
[0018] Semliki Forest virus (SFV) belongs to genus Alphavirus (family Togaviridae) together with 27 other known viruses. Alpha viruses infect their vertebrate hosts (mammals, birds and fish) and invertebrate transmission vectors (mosquitoes). In infected organisms the alpha viruses replicate in different cells to a high titer.
[0019] Alphavirus genome encodes for two protease activities—one is associated with virus coat protein which is an autoproteinase and another with non-structural protein nsP2, which cleaves three cleavage sites in alpha virus non-structural polyprotein P1234 (Merits et al., 2001, J. Gen Virol. 2001: 82:765-773). These cleavage sites have different consensus sequences and they differ from each other by the mode of proteolytic cleavage (in cis or in trans), the enzymatic activity required for the cleavage (intact nsP2 or protease domain of nsP2) and by the cleavage efficiency (Vasilieva et al., 2001: J. of Biol. Chem. 276(33): 30786-30793).
[0020] NsP2 consists of two enzymatically active domains: N-terminal NTPase/helicase/RNA triphosphatase domain and C-terminal cystein protease domain. Both domains are needed for virus replication and for processing of the second cleavage site in SFV polyprotein, while only the C-terminal protease domain is needed for processing the third cleavage site (between nsP3 and nsP4). Cysteine 481 and histidine 558 have been identified as essential residues for the protease activity of nsP2. It has been shown that nsP2 protease domain (hereafter named Pro39) can be expressed as recombinant protein in E. coli, purified with Ni-NTA chromatography and used for in vitro processing of the recombinant substrates, containing 37 aa region of the protease recognition site (19 aa residues upstream and 18 aa residues downstream of the cleavage point; hereafter 19/18 recognition site). (Vasiljeva et al. 2001). The cleavage is highly specific and active; Pro39 is capable to process 50% of 400-fold molar excess of substrate in 5 minutes. (Vasilieva et al., 2001). FIG. 1 illustrates the structure and processing pattern of SFV nonstructural polyprotein.
[0021] One of the biological functions of cleavage of the protease site between nsP3 and nsP4 proteins is to release the nsP4 from P1234 precursor protein and from alpha virus early replicase complex. SFV, in contrast to majority of alpha viruses analyzed to the date produces atypically large amounts of P1234 polyprotein; in case of most other alpha viruses the P1234 production is about 20 fold down-regulated by presence of leaky termination codon at the end of nsP3 region. This leads us to believe that compared to most alpha virus proteases the SFV nsP2 protease should have a higher cleavage activity for the last processing site, since it has to digest significantly higher amounts of substrate. It may also be that proteases from other alpha viruses may have similar high activities.
SUMMARY OF THE INVENTION
[0022] The present invention relates to linear protease recognition site from the SFV encoded polyprotein which in truncated and modified forms can be used as highly efficient and precise target sequence for the SFV non-structural protease nsP2 and for its C-terminal protease domain Pro39. The target sequence has earlier been identified as a 37 aa long sequence which however, is far too large for use in any practical expression system. On the contrary, the present disclosure provides a target sequence that can easily be used in various expression systems.
[0023] The present disclosure provides details of the protease recognition site requirements. This disclosure shows that the target sequence of Pro39 can surprisingly be truncated into shorter but still very efficiently cleavable variants. The cleavage efficiency for the artificial protease substrates containing these sequences is somewhat lower than the efficiency of full-size 19/18 recognition site, but unexpectedly it is high enough to enable protease to process over 10-fold molar excesses of substrate within one hour. According to the present disclosure the cleavage specificity was also maintained for these truncated sites. The preferred sequences according to the present disclosure for active recognition site variants are:
1. (−10)DVLRLGRAGA(↓)YIFSS (+5), (SEQ ID NO: 1) designated as 10/5 site 2. (−6)LGRAGA(↓)YIFSS (+5); (SEQ ID NO:2) designated as 6/5 site.
[0024] Moreover, the present disclosure shows that the +1 amino acid residue of the protease recognition site can be substituted from native Y (tyrosine) to virtually any type of amino acid with no change of protease cleavage specificity. If the native Y residue is substituted with S (serine) and R (arginine) residues the cleavage site recognition and/or processing efficiency is significantly enhanced. G (glycine) was found to be the best residue to substitute native Y residue as the substrate containing G was processed 3 fold more effectively as compared to native Y containing substrate. Substrates with R and S residues are processed 2 fold more efficiently as compared to substrates with native Y in the same position.
[0025] Even further, the present disclosure shows that the protease recognition downstream region can be substituted with His-tag repeat. Such substitution does not affect the cleavage as such but only the efficiency of the cleavage.
[0026] In one aspect of the invention these inventive steps are successfully combined. It is demonstrated that artificial truncated substrates with altered +1 amino acid residues are efficiently recognized and actively processed by Pro39, the processing is more rapid and complete as compared to substrates where it truncated sites are used. Preferred embodiments of the present invention therefore include the following variants of the highly effective protease recognition sites:
3. (−10)DVLRLGRAGA(↓)RIFSS (+5), (SEQ ID NO:3) designated as 10/R5 site 4. (−6)LGRAGA(↓)RIFSS (+5); (SEQ ID NO:4) designated as 6/R5 site 5. (−10)DVLRLGRAGA(↓)GIFSS (+5), (SEQ ID NO:5) designated as 10/G5 site 6. (−6)LGRAGA(↓)GIFSS (+5); (SEQ ID NO:6) designated as 6/G5 site 7. (−6)LGRAGA(↓)SIFSS (+5); (SEQ ID NO:32) designated as 6/S5 site 8. (−10)DVLRLGRAGA(↓)SIFSS (+5), (SEQ ID NO:33) designated as 10/S5 site
[0027] Importantly, cleavage specificity is preserved for all of these modified recognition sites.
[0028] In another aspect of this invention the ability of Pro39 to process differently positioned modified recognition sites in recombinant target protein was examined. Positioning the recognition sequence between highly structured thioredoxine domains does surprisingly not cause decrease of protease cleavage efficiency, but on the contrary, the cleavage efficiency is significantly enhanced as compared to cleavage of recognition sites placed between structured and non-structured protein sequences.
[0029] According to the present disclosure Pro39 cleaves substrates possessing the truncated and modified recognition site in wide temperature range (including low temperatures) 4-39° C., in neutral pH region (i.e. pH 7-8) and in presence of high concentration NaCl (up to 4 M) or urea (up to 1.5 M). Furthermore, according to the present disclosure the cleavage of the substrates possessing the truncated and modified recognition sites can be reversibly inhibited by addition of Zn-ions and re-activated by addition of EDTA. Furthermore, Pro39 cleaves substrates having the recognition site according to this disclosure both in liquid phase as well as in resin-bound state.
[0030] One object of the present invention is to use modified recognition sites for Pro39 for removal of large and structured protein tags such as thioredoxine, GST (glutathione S-transferase), MBP (maltose binding protein) or CBP (calmoduline binding protein) from recombinant proteins.
[0031] Another object of the present invention is to insert the modified recognition site(s) for Pro39 into recombinant protein sequence and the recombinant protein can subsequently be processed into subdomains with desired sizes.
[0032] A still another object of the present invention is to provide a cleavage site and a protease that can be used in wide temperature range, at neutral pH, and under high salt concentration. Moreover, an object of the present invention is to provide a cleavage site and protease that can be used as well in liquid phase as in a resin bound stage.
[0033] An even further aspect of the present invention is to provide expression vectors comprising sequences encoding recombinant proteins and modified recognition sites for Pro39 to subsequently process the protein
BRIEF DESCRIPTION OF THE FIGURES
[0034] FIG. 1 shows the source of the protease and its recognition sequence. The structure and processing pattern of SFV non-structural polyprotein are shown. Protease recognition sequence (native nsP3/nsP4 site) is given in one letter code; bond cleaved by protease is indicated by arrow. The domain structure of nsP2 protease is shown; asterisk indicates the position of catalytic cystein residue in Pro39 domain.
[0035] FIG. 2 shows examples of results obtained by mass-spectrometry analysis of the recombinant substrates processed in vitro by Pro39. Analysis was performed by use of MALDI TOF Voyager DE Pro instrument (Applied Biosystem). The names of the substrates are indicated on each panel.
[0036] FIG. 3A represents a schematic structure of the recombinant substrates used for determination of influence of the length of upstream region of the ¾ cleavage site on the cleavage efficiency of Pro39. (In the figures the cleavage site is called ¾ cleavage site because in vivo the site is between nsP3 and nsP4).Trx indicates thioredoxin tag. The arrow on the top indicates the position of Pro39 cleavage. HHHHHHHH is a histidine tag used for purification of the substrate.
[0037] FIG. 3B shows influence of the length of upstream region of the ¾ cleavage site on the cleavage efficiency of Pro39. Recombinant substrates as illustrated in FIG. 3A were used for cleavage. Purified substrates were incubated with Pro39 for 60 minutes at 30° C in molar ration 20:1. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. Substrates are indicated at the top of each lane. Lane 1 contains the control substrate with no Pro39 added. The position of Pro39, substrates and cleavage products are indicated at the right hand side of the blot.
[0038] FIG. 4A shows the structure of the recombinant substrates used for analyzing the role of upstream and downstream regions in processing of the ¾ site. EGFP indicates Enhanced Green Florescent Protein. Upstream regions of the cleavage sites are shown as shadowed boxes, and downstream regions as clear boxes. The C-terminus of all substrates contains a Leu-Glu dipeptide followed by 8× His tag. The arrow indicates the position of the cleavage.
[0039] FIG. 4B demonstrates the role of upstream and downstream regions of the processing of the ¾ site. Recombinant substrates illustrated in FIG. 4A were used for the cleavage. Purified substrates were incubated with Pro39 for 60 minutes at 30° C. in molar ratio 20:1. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. Substrates are indicated on the top of each lane. Lane 1 contains the control substrate (E2-EGFP 20/20′) with no Pro39 added. Positions of Pro39, substrates and cleavage products are indicated at the right hand side of the blot.
[0040] FIG. 5A shows a schematic structure of the recombinant substrate used for analysis of the role of the P1′ (position 1) residue in processing of the ¾ site. Trx indicates thioredoxin tag, and the amino acid sequence surrounding the cleavage site is given in one letter code. Amino acid residue at position P1′ is indicated with boldface X. Arrow indicates the position of Pro39 cleavage.
[0041] FIG. 5B demonstrates effect of random mutagenesis of downstream amino acid residue P1′ (position 1) for processing of the ¾ site. Pro39 digestion of substrates as illustrated in FIG. 5A with different amino acid residues at position P1′ of the ¾ site were used. Purified substrates were incubated with Pro39 for 60 minutes at 30° C. in molar ratio 20:1. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. The amino acid residue at position P1′ is indicated at the top of the panel. Lane 1 contains the control substrate with no Pro39 added. The positions of Pro39, substrates, and cleavage products are indicated on the right hand side of the blot.
[0042] FIG. 6A shows schematic structures of the recombinant substrates used for demonstrating that Pro39 prefers substrates where recognition sequence is placed between two highly structured protein domains. Trx indicates thioredoxin tag, Ter indicates the non-structured truncated Trx tag. Arrow indicates the position of Pro39 cleavage.
[0043] FIG. 6B demonstrates Pro39 digestion of substrates as illustrated in FIG. 5A with one structured tag (left panel) and with two structured tags (right side panel). Purified substrates were incubated with Pro39 for 60 minutes at 30° C. in molar ratio 20:1. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. The name of substrate is indicated at the top of each lane. Lane 1 on both panels contains the control substrate with no Pro39 added. Positions of Pro39, substrates and cleavage products are indicated on the right hand side of the blot.
[0044] FIG. 7 illustrates the effects of cleavage conditions for processing of the modified recognition sites by Pro39. The substrate used in this experiment was Trx fused with 10/5 recognition site.
[0045] A. Effect of temperature. Purified substrate was incubated with Pro39 for 60 minutes in molar ratio 20:1 at temperature indicated on the top of each lane. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. Lane 1 contains the same substrate with no Pro39 added. Positions of Pro39, substrates and cleavage products are indicated on the right hand side of the blot.
[0046] B. Effect of pH. Purified substrate was incubated with Pro39 for 60 minutes at 30° C. in molar ration 20:1 in HEPES buffer with pH indicated at the top of each lane. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie staining. Positions of Pro39, substrates and cleavage products are indicated on the right hand side of the blot.
[0047] FIG. 8 illustrates the effects of cleavage conditions for processing of the modified recognition sites by Pro39. The substrate used in this experiment was Trx fused with 10/5 recognition site.
[0048] A. Activity of Pro39 in presence of high molar salt. Purified substrate was incubated with Pro 39 for 60 minutes at 30° C. in molar ration 20:1 in presence of NaCl concentrations indicated at the top of each Lane. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. Lane 1 contains the same substrate with no Pro39 added. Positions of Pro39, substrates and cleavage products are indicated on the right hand side of the blot.
[0049] B. Activity of Pro39 in presence of urea. Purified substrate was incubated with Pro39 for 60 minutes at 30° C. in molar ration 20:1 at presence of urea concentrations indicated at the top of each lane. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. Lane 1 contains the same substrate with no Pro39 added. Positions of Pro39, substrates and cleavage products are indicated on the right hand side of the blot
[0050] FIG. 9 demonstrates the reversible inhibition of Pro39 at the presence of zinc ions. Purified substrate was incubated with Pro39 at 30° C. in molar ration 20:1. Lane 1 (control) contains substrate with no Pro39 added. Lane 2 represents the products of reaction after 10 minutes of incubation. Lane 3 represents the products of reaction incubated for 10 minutes, stopped by addition of zinc ions and incubated for an additional 60 minutes. Lane 4 represent the products of reaction incubated for 10 minutes, stopped by addition of zing, reactivated by addition of EDTA and incubated for an additional 60 minutes. Lane 5 represents the products of reaction after 60 minutes of incubation with no zinc addition. Position of Pro39, substrates and cleavage products are indicated on the right hand side of the blot.
[0051] FIG. 10A shows the schematic structure of TAP-DBD substrate used to demonstrate Pro39 cleavage of substrate purified on anti-E2Tag antibody conjugated Sepharose resin. E2Tag indicates sequence SSTSSDFRDR (SEQ ID NO: 7) recognized by anit-E2Tag antibody 5El 1, E4Tag indicates sequence GTTGHYSVRD (SEQ ID NO: 8) recognized by anti-E4Tag antibody 1E2, DBD represents BPV-1E2 protein DNA Binding and Dimerization domain. Arrow indicates the position of Pro39 cleavage.
[0052] FIG. 10B demonstrates Pro39 cleavage of substrate purified on anti-E2Tag antibody conjugated Sepharose resin. Purified substrate TAP-DBD as illustrated in FIG. 10A was incubated with Pro39 at 30° C. for times indicated at the top of each lane. Reaction products were analyzed by Western Blot method using anti-E4Tag antibody 1E2 and goat anti-mouse IgG alkaline phosphatase conjugate as secondary antibody. Signals visualized using bromochloroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). Lane 1 represents non purified substrate (TAP-DBD lysate). Lane 2 represents the products of reaction after 2 hours incubation. Lane 3 represents the products of reaction after 4 hours incubation. Positions of substrate and cleavage products are indicated on the right hand side of the blot.
[0053] FIG. 11A shows a schematic structure of HisTag-EGFP-HisTag substrate used to demonstrate effect of low incubation temperature on the Pro39 cleavage activity. FIG. 11B demonstrates activity of Pro39 on the recombinant substrate under low temperature conditions. Purified substrate (E2Tag-HisTag-EGFP-HisTag as illustrated in FIG. 11A , was incubated with Pro39 in molar ratio 10:1 at 8C for times indicated on top of each lane. Reaction products were analyzed by Western Blot method using anti-His antibody and goat anti-mouse IgG alkaline phosphatase conjugate as secondary antibody. Signals were visualized using bromoclhoroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). Lane 1 represents the products of reaction after 23 hours incubation. Lane 2 represents the products of reaction after 6 hours incubation. Lane 3 represents the products of reaction after 9 hours incubation. Lane 4 resents the products of reaction after 21 hours incubation. Lane 5 represents non treated substrate and Pro39 as molecular weight markers. Positions of Pro39, substrate and cleavage products are indicated on the left hand side of the blot.
[0054] FIG. 12 demonstrates cleavage of column-bound substrate TAP-DBD (illustrated in FIG. 10A ) by Pro 39 on column. Reaction products were analyzed by Western Blot method using anti-E4Tag antibody 1E2. Goat anti-mouse IgG alkaline phosphatase conjugate was used as secondary antibody. Signals were visualized using bromoclhoroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). Lane 1 represents total cell lysate. Lane 2 represents flow through fraction after Pro39 cleavage. Lane 3 represents elution of cleavage product. Lane 4 represents column-bound fraction (uncleaved substrate and cleavage products) after Pro39 cleavage and elution. Positions of substrate and cleavage products are indicated on the right hand side of the blot.
[0055] FIG. 13 demonstrates cleavage of column-bound substrate TAP-DBD (illustrated in FIG. 10A ) by Pro39 on column. Reaction products were analyzed by Western blot method using anti-E2Tag antibody 5E11. Goat anti-mouse IgG alkaline phosphatase conjugate was used as secondary antibody. Signals were visualized using bromoclhoroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). Lane 1 represents total cell lysate. Lane 2 represents flow through fraction after Pro39 cleavage. Lane 3 represents elution of cleavage product. Lane 4 represents column-bound fraction after Pro39 cleavage and elution. The positions of substrate and cleavage product are indicated on the right hand side of the blot.
[0056] FIG. 14 demonstrates that column-bound substrate TAP-DBD (illustrated in FIG. 10A ) is not cleaved without Pro39. In this control experiment anti-E2Tag antibody conjugated Sepharose resin bound substrate was incubated without Pro39 in buffer under the same conditions as with Pro39. Reaction products were analyzed by Western Blot method using anti-ETag antibody 1E2. Goat anti-mouse IgG alkaline phophatase conjugate was used as secondary antibody. Signals were visualized using bromoclhoroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). Lane 1 represents total cell lysate. Lane 2 represents flow through fraction after Pro39 cleavage. Lane 3 represents elution of cleavage products. Lane 4 represents column-bound fraction after Pro39 cleavage and elution. Position of substrate is indicated on the right hand side of the blot.
[0057] FIG. 15 demonstrates that column bound substrate TAP-DBD (illustrated in FIG. 10A ) is not cleaved without Pro39. In this control experiment anti-E2Tag antibody conjugated Sepharose resin bound substrate was incubated without Pro39 in buffer under the same conditions as with Pro39. Reaction products were analyzed by Western Blot method using anti-E2Tag antibody 5E11. Goat anti-mouse IgG alkaline phosphatase conjugate was used as secondary antibody. Signals were visualized using bromoclhoroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). Lane 1 represents total cell lysate. Lane 2 represents flow through reaction after Pro39 cleavage. Lane 3 represents elution of cleavage products. Lane 4 represents column-bound fraction after Pro39 cleavage and elution. Positions of substrate and cleavage of the product are shown on the right hand side of the blot.
[0058] FIG. 16 shows the design of a vector for purposes of expression of recombinant proteins in mammalian cells. The vector is based on vector pQM-CMV-E2-N-A-intron (Quattromed Ltd. catalog number P1-114-020) Underlined sequences indicate cloning adapters for Bam HI and HindIII sites. Dotted underlined sequences indicate 6×His-tag encoding sequence. Double underlined sequences indicate cleavage site for Pdi1 (NaeI).
[0059] FIG. 17 shows the design of a vector for purposes of expression of recombinant proteins in mammalian cells. The vector is based on vector pQM-CMV-E2-N-A-intron (Quattromed Ltd. catalog number P1-114-020). Underlined sequences indicate cloning adapters for Bam HI and Hind III sites. Dotted underlined sequences indicate 6× His-tag encoding sequence. Double underlined sequences indicate CGC codon for R (Arginine) activates the cleavage of recombinant protein.
[0060] FIG. 18 depicts the full sequence of pQM-CMV-E2Tag-N-A-intron vector. The vector is of 5055 bps. Nucleotides 1-444 are for PolyA tail, 444-644 for SV40Ori, 2503-1643 for Amp, 3584-4189 for CMV, 4190-4259 for the leader, 4275-4304 E2Tag, 4304-4336 for Multiple Cloning Site and 4336-5055 intron.
DETAILED DESCRIPTION OF THE INVENTION
[0061] The present invention is related to linear protease recognition site from the SFV encoded polyprotein P1234 which, in truncated and modified forms can be used as highly efficient and precise target sequence for the SFV non-structural protease nsP2 and for its C-terminal protease domain Pro39. In contrast to the previously identified target sequence, which is 37 aa long, and as such far too large to be used in practical expression systems, this disclosure provides shortened and still active variants as well as minimal, but still recognizable and cleavable forms of the recognition site. Additionally, this disclosure provides highly efficient modifications of the recognition site.
[0062] We produced a specific set of expression vectors (for prokaryotic expression and for in vitro translation) for analysis purposes. Extensive analysis was preformed using both in vitro translated substrates as well as substrates expressed in E. coli and purified as recombinant proteins by using Ni-NTA chromatography. Using crude deletion analysis we successfully demonstrated that the recognition site for the Pro39 can be considerably shortened. This shortening of recognition sequence eventually led to gradual decrease on the processing efficiency and was used for preliminary mapping of essential sequences. The precise mapping of the essential sequences was made by construction of the protease recognition sequence variants from synthetic oligonucleotides. The cleavage efficiency of the artificial protease substrates, selected as results of this procedure, was somewhat lower than for substrates containing the full-size 19/18 recognition site, but markedly it was high enough to enable protease to process over 10-fold molar excess of substrate within one hour. MALDI-TOF mass-spectrometry showed that the cleavage specificity surprisingly was also maintained for these truncated sites ( FIG. 2 first panel). These sequences of detected active recognition site variants are among preferred embodiments of the invention and are as follows:
1. (−10)DVLRLGRAGA(↓)YIFSS (+5), (SEQ ID NO:1) designated as 10/5 site 2. (−6)LGRAGA(↓)YIFSS (+5); (SEQ ID NO:2) designated as 6/5 site.
[0063] The intermediate variants, containing 9, 8 or 7 aa from the nsP3 region (upstream region with the respect of cleavage point) were cleaved specifically but with significantly lower efficiency ( FIG. 3 ). Based on the fact that longer sequences are able to become organized into an alpha helical structure we conclude that one preferred embodiment according to the present invention is an expression vector design having an alpha-helical region in the protease recognition site. Another preferred embodiment is insertion of a protease recognition site with an alpha-helical region into a recombinant protein to be cleaved. These embodiments are supported also with the data shown in FIG. 6 , where non structured Ter substrate is poorly cleaved while Trx substrate is effectively cleaved.
[0064] Multiple biotechnological approaches require production of proteins with native N-terminus which, quite often, starts with an amino acid different from methionine. The same applies for processing proteins in in vitro conditions with the aim to produce stabilized or destabilized proteins (use of the N-end rule in cell). This approach can serve as powerful approach to create conditional protein knockout (protein will be destabilized and rapidly degraded after removal of stabilizing amino acids from its N-terminus) or knock-in constructs (recombinant protein will be stabilized after removal by protease destabilizing elements like pest-sequences or ubiquitine fusion part). To obtain the recombinant proteins or their subdomains with native N-terminal residues there is a need for a protease being able to cleave specifically substrates with any amino acid residue at its N-terminus (in other words, all elements required for protease site recognition and protease activity should be located upstream from the cleavage point). At the same time site specificity should be maintained. The invention according to the present disclosure is applicable to these approaches.
[0065] We performed a two step functional analysis and found out that recognition sequence of Pro39 and the corresponding enzyme meet the criteria set forth above. First, deletion mutagenesis of the protease recognition consensus downstream region was carried out. This experiment showed that the downstream region is not needed for cleavage as such to take place, only the cleavage efficiency was affected ( FIGS. 4A and B). When the downstream region was substituted with His-tag repeat containing two amino acids (-LEHHHHHHHH-SEQ ID NO: 9) introduced by XhoI restriction cloning procedure only the cleavage efficiency was affected. Secondly, the extensive site-directed mutagenesis of +1 amino acid residue was carried out. The oligonucleotide derived constructs encoding protease recognition site in configuration +15/X (where X indicates the variable amino acid residue) were cloned into vectors, expressing recombinant substrates. We demonstrated by using expressed and purified substrates that the N-terminal amino acid residue of the protease recognition site can be substituted from Y (tyrosine) to virtually any type of amino acids (S, G, R, N, D, E, C, M, V, L and A) except P without any change of protease cleavage specificity ( FIG. 2 and FIG. 5 ). Most importantly, these experiments clearly indicated that if the native +1 amino acid residue Y (tyrosine) was substituted with S (serine), R (arginine) or G (glycine) residues the cleavage site recognition and/or processing efficiency was significantly enhanced ( FIG. 5 ). This finding also indicates that other residues of the cleavage consensus are useful for the cleavage activity and opens possibility for future selection of high-efficiency cleavage consensuses.
[0066] This disclosure shows that artificial truncated substrates with altered +1 amino acid residues were efficiently recognized and actively processed by Pro39. When activating (G, S or R) amino acids were used as +1 amino acid residues, the processing was more rapid and complete as compared to substrates where wild type truncated sites where used. At the same time the rule that the most efficient cleavage required 10 or 6 native upstream amino acid residues remained unchanged. This led us to conclude that following variants of the highly effective protease recognition sites are among preferred embodiments of the invention:
3. (−10)DVLRLGRAGA(↓)RIFSS (+5), (SEQ ID NO:3) designated as 10/R5 site 4. (−6)LGRAGA(↓)RIFSS (+5); (SEQ ID NO:4) designated as 6/R5 site 5. (−10)DVLRLGRAGA(↓)GIFSS (+5), (SEQ ID NO:5) designated as 10/G5 site 6. (−6)LGRAGA(↓)GIFSS (+5); (SEQ ID NO: 6) designated as 6/G5 site 7. (−6)LGRAGA(↓)SIFSS (+5); (SEQ ID NO:32) designated as 6/S5 site 8. (−10)DVLRLGRAGA(↓)SIFSS (+5), (SEQ ID NO:33) designated as 10/S5 site
[0067] Importantly, cleavage specificity was preserved for all of these modified recognition sites (demonstrated by mass-spectrometry). All this leads us to conclude that one preferable embodiment of the present invention includes insertion of 10/0 or 6/0 recognition sites into a recombinant protein for protease cleavage with Pro39 so that:
alpha-helical region of the protease recognition site is preserved the +1 position of the newly inserted cleavage consensus most preferably is G, S or R residue and preferably also T or K residue (processing product will have these aa residues at its N-terminus), +1 position of the newly inserted cleavage consensus may also be any other residue than P, D or E provided that more protease units are used to obtain the same cleavage efficiency.
[0071] Two sets of recombinant proteins with inserted protease sites were used for studying the ability of Pro39 to process the modified recognition sites positioned differently in recombinant target protein:
[0072] 1. recombinant protein consisted of two full size thioredoxine domains and modified protease recognition site between them (shown in FIG. 6A ). In this case the protease recognition site is positioned between two compact protein domains (each with size approximately 100 aa residues).
[0073] 2. recombinant protein consisted of full size thioredoxine domain (compact structure) followed by protease recognition site and truncated C-terminal region (40 aa residues) of thioredoxin (non-structured domain) (shown in FIG. 6A ). In this case protease recognition site is positioned between compact N-terminal domain and non-structural smaller C-terminal domain.
[0074] Positioning of the recognition sequence between highly structured thioredoxine domains did not cause the decrease of protease cleavage efficiency, but surprisingly on the contrary, the cleavage efficiency was significantly enhanced as compared to cleavage of recognition sites placed between structured and non-structured protein sequences ( FIG. 6B ) Signals were visualized using bromoclhoroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). Therefore, according to one preferred embodiment of the current invention modified recognition site for Pro39 can be used for removal of large and structured protein tags such as thioredoxine, GST, MBP or CBP from recombinant proteins. According to another preferred embodiment modified recognition site(s) for Pro39 can be inserted into recombinant protein sequence and the recombinant protein can subsequently be processed into subdomains with desired sizes.
[0075] A still another aspect the present invention provides the conditions for use of the Pro39 for cleavage of the recombinant proteins containing the modified recognition sequences. This is essential part of the invention, since there has been an unmet need for a protease operable in wide range of conditions. A wide variety of conditions was tested to estimate stability of Pro39 and its preferences for cleavage of recombinant substrates. According to this disclosure Pro39 cleaves these substrates in wide temperature range including low temperatures with temperature optimum around 30° C. ( FIGS. 7A and 11 ). An important aspect of this invention is that substrates with modified recognition sites can be cleaved by Pro39 at +4° C. property which may be highly useful for processing of delicate and temperature sensitive recombinant proteins. Cleavage activity was maintained also at as high temperature as 39° C. but with greatly reduced efficiency ( FIG. 7A ).
[0076] Pro39 cleaves the substrates in neutral pH region ( FIG. 7B ) in most commonly used buffer systems, including Tris, HEPES and phosphate buffers. The pH optimum was detected to be about 7.5-8.0 and the HEPES buffer as the most suitable buffer for maximal cleavage efficiency.
[0077] Pro39 cleaves these substrates at the presence of high concentration of NaCl (up to 4 M) or urea (up to 1.5M) ( FIGS. 8A and B). This feature is important because it allows protease cleavage in conditions where protein-protein interactions are minimized (high NaCl concentrations). For example this includes cleavage of the substrates purified by immuno-absorption chromatography or ion-exchange chromatography without previous desalting of the eluted proteins. Capability to cleave in presence of high concentration of urea can be used for cleavage of partially denatured (or renatured) proteins. This can be important if the protease site is not opened for cleavage under native conditions.
[0078] Cleavage of these substrates by Pro39 can be reversibly inhibited by addition of Zn-ions and re-activated by addition of EDTA. Low concentration of Zn-ions cause rapid and complete block of the processing, removal of Zn-ions activates the processing ( FIG. 9 .). This property can be used to block premature or unwanted processing of recombinant proteins. This also indicates that addition of EDTA is needed for the cleavage buffer to remove endogenous inhibitors of protease activity. For that it was demonstrated the EDTA does not suppress processing by Pro39 even at high concentrations (up to 100 mM).
[0079] Pro39 cleaves these substrates both in liquid phase as well as in resin-bound state on the immuno-absorption column ( FIG. 11-15 ). This allows easy performance of the protease reaction as well as simple separation of the cleaved products for unprocessed material.
[0080] 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 1
Construction of Vectors for Expression of Recombinant Proteins in Mammalian Cells
[0081] Vector 1 was designed based on the vector pQM-CMV-E2-N-A-int (Quattromed Ltd. P1-114-020). Full sequence of the vector is shown in FIG. 18 . The design of vector 1 is shown in FIG. 16 . Full sequence of the This vector was designed so that it allows both precise positioning of the N-terminus of recombinant protein into +1 position of protease cleavage site as well as cloning downstream of the +5 position of modified protease consensus for higher efficiency of the cleavage. Introduction of cleavage site Pdil changes +1 residue in protease recognition site to G, but does not change invariant position of −1. The sequence of the protease recognition site in this vector is thereby according to SEQ ID NO: 5.
[0082] Vector 2 is designed for cloning of recombinant protein expressing gene downstream of optimized 10/R5 cleavage site for maximally efficient cleavage of recombinant protein. The vector is based on vector pQM-CMV-E2-N-A-int (Quattromed Ltd.). Full sequence of the vector is shown in FIG. 18 . The design of vector 2 is shown in FIG. 17 . The CGC codon for arginine (underlined in the figure) is designed to activate the cleavage of recombinant protein. The protease recognition site in this vector is according to SEQ ID NO:3.
EXAMPLE 2
[0083] Design of insertion elements which can be used in QM-CMV-E2-N-A-intvector (Quattromed Ltd. Catalog number P1-114-020) based constructs and/or directly inserted into chosen position of recombinant protein using site-specific mutagenesis Cassette designs are based on the use of optimized 1I0/R5 or 6/R5 sites (SEQ ID NO: 3 and SEQ ID NO: 4, respectively). These sites can be inserted into expression vector or introduced directly into recombinant protein encoding sequence by site directed mutagenesis:
10/R5 5′ GAC GTC CTG CGA CTA GGC CGC GCG GGT GCC CGC ATT TTC TCC TCG 3′ 3′ CTG CAG GAC GCT GAT CCG GCG CGC CCA CGG GCG TAA AAG AGG AGC 5′ D V L R L G R A G A R I F S S G
[0084] Construct was made by using oligonucleotides:
5′GA TCT GAC GTC CTG CGA CTA GGC CGC GCG GGT GCC CGC ATT TTC TCC TCG GGA TCC A 3′A CTG CAG GAC GCT GAT CCG GCG CGC CCA CGG GCG TAA AAG AGG AGC CCT AGG TTC GA
[0085] Oligos were annealed and cloned into the vector pQM-CMV-E2-N-A-int, digested with restrictases BamHI and HindIII. The underlined GCG codon codes for arginine, which activates the cleavage of recombinant protein.
6/R5 5′ CTA GGC CGC GCG GGT GCC CGC ATT TTC TCC TCG 3′ 3′ GAT CCG GCG CGC CCA CGG GCG TAA AAG AGG AGC 5′ L G R A G A R I F S S G
[0086] Construct was made by using oligonucleotides:
5′GA TCT CTA GGC CGC GCG GGT GCC CGC ATT TTC TCC TCG GGA TCC A 3′A GAT CCG GCG CGC CCA CGG GCG TAA AAG AGG AGC CCT AGG TTC GA
[0087] Oligos were annealed and cloned into the vector pQM-CMV-E2 N-Aint, digested with restrictases BamHI and HindIII. The underlined GCG codon codes for arginine, which activates the cleavage of recombinant protein.
[0088] The insertion strategy is also usable for non-optimized 10/0 and 6/0 type cassettes, which can be used for production of cleavage products with exact N-terminal amino acid residues.
[0089] Cassette designs are based on the use of use non-optimized 10/0 or 6/0 sites which can be inserted into expression vector or introduced directly into recombinant protein encoding sequence by site directed mutagenesis.
10/0 5′ GAC GTC CTG CGA CTA GGC CGC GCG GGT GCC 3′ 3′ CTG CAG GAC GCT GAT CCG GCG CGC CCA CGG 5′ D V L R L G R A G A
[0090] Construct was made by using oligonucleotides:
5′GA TCT GAC GTC CTG CGA CTA GGC CGC GCG GGT GCC CGC GGA TCC A 3′A CTG CAG GAC GCT GAT CCG GCG CGC CCA CGG GCG CCT AGG TTC GA
[0091] Oligonucleotides were annealed and cloned into the vector pQM-CMV-E2-N-A-int, digested with restrictases BamHI and HindIII.
6/0 5′ CTA GGC CGC GCG GGT GCC 3′ 3′ GAT CCG GCG CGC CCA CGG 5′ L G R A G A
[0092] Construct was made using oligonucleotides:
5′GA TCT CTA GGC CGC GCG GGT GCC GGA TCC A 3′A GAT CCG GCG CGC CCA CGG CCT AGG TTC GA
[0093] Oligonucleotide were annealed and cloned into the pQM-CMV-E2-N-Aint, digested with restrictases BamHI and HindIII.
EXAMPLE 3
Identification of the Minimal Cleavage Consensus of Pro 39 Using Deletion Mutagenesis
[0094] The analysis of the cleavage consensus requirements was made as a two step experiment. First, the set of constructs, expressing recombinant proteins with truncated protease recognition sites were made. For this purpose the green fluorescent protein was fused with following truncated cleavage consensus elements constructed by PCR:
[0095] 20/20 site (control, previously reported to serve as excellent substrate for Pro39), encoding the recognition peptide with SEQ ID NO: 10 as follows:
S G I T F G D F D D V L R L G R A G A ↓ Y I F S S D T G S G H L Q Q K S V R . . . . . . . . . . − 19 −15 −10 −5 −1 +1 +5 +10 +15 +18
[0096] 15/20 site (construct 1) encoding the recognition peptide with SEQ ID NO: 11 as follows:
F G D F D D V L R L G R A G A ↓ Y I F S S D T G S G H L Q Q K S V R . . . . . . . . . −15 −10 −5 −1 +1 +5 +10 +15 +18
[0097] 10/20 site (construct 2) encoding the recognition peptide with SEQ ID NO:12 as follows:
D V L R L G R A G A ↓ Y I F S S D T G S G H L Q Q K S V R . . . . . . . . −10 −5 −1 +1 +5 +10 +15 +18
[0098] 5/20 site (construct 3) encoding the recognition peptide with SEQ ID NO:13 as follows:
G R A G A ↓ Y I F S S D T G S G H L Q Q K S V R . . . . . . . −5 −1 +1 +5 +10 +15 +18
[0099] 20/15 site (construct 4) encoding the recognition peptide with SEQ ID NO:14 as follows:
S G I T F G D F D D V L R L G R A G A ↓ Y I F S S D T G S G H L Q Q K . . . . . . . . . − 19 −15 −10 −5 −1 +1 +5 +10 +15
[0100] 20/10 site (construct 5) encoding the recognition peptide with SEQ ID NO:15 as follows:
S G I T F G D F D D V L R L G R A G A ↓ Y I F S S D T G S G . . . . . . . . − 19 −15 −10 −5 −1 +1 +5 +10
[0101] 20/5 site (construct 6) encoding the recognition peptide with SEQ ID NO: 16 as follows:
S G I T F G D F D D V L R L G R A G A ↓ Y I F S S . . . . . . . − 19 −15 −10 −5 −1 +1 +5
[0102] 20/0 site (construct 7) encoding the recognition peptide with SEQ ID NO: 17 as follows:
S G I T F G D F D D V L R L G R A G A ↓ (LE)HHHHHHHH . . . . . − 19 −15 −10 −5 −1
[0103] The eight substrates (green fluorescent protein fused with the eight recognition site variant given above) are schematically illustrated also in FIG. 4A .
[0104] All eight substrates were expressed in E. coli and purified as recombinant proteins using Ni-NTA chromatography and subjected to the processing with Pro39. Purified substrates were incubated with Pro39 for 60 minutes at 30° C. in molar ratio 20:1. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. The results clearly demonstrate that the recognition site for the Pro39 can be considerably shortened. Referring to FIG. 4B :
as little as 5 aa residues from upstream side is needed for the processing to take place. However recombinant protein including construct 3 (5/20 site according to SEQ ID NO: 13) was processed considerably slower than recombinant proteins with 15 or 10 aa residues from the region upstream of the cleavage site. no virus specific aa residues were needed on the downstream side for the processing to take place. However, processing of the recombinant protein including construct 7 (20/0 site according to SEQ ID NO: 17) was rather ineffective as compared to that of recombinant proteins including constructs 4, 5, and 6 (20/15 site according to SEQ ID NO: 14, 20/10 site according to SEQ ID NO: 15 and 20/5 site according to SEQ ID NO: 16, respectively)
[0107] Based on these results we subjected substrates having 15 to 5 aa residues from upstream and 0-5 aa residues from downstream region of the protease recognition site for more detailed analysis.
EXAMPLE 4
Identification of the Precise Minimal Cleavage Consensus of Pro 39 Using Oligonucleotide Insertion Mutagenesis
[0108] The precise mapping of the essential sequences was made by construction of the protease recognition sequence variants from synthetic oligonucleotides. FIG. 3A illustrates schematically the substrates comprising oligonucleotide duplexes, encoding for following cleavage site variants:
[0109] 10/5 site (construct 8) encoding the recognition peptide with SEQ ID NO: 1 as follows:
D V L R L G R A G A ↓ Y I F S S −10 −9 −8 −7 −6 −5 −4 −3 −2 −1 +1 +2 +3 +3 +5
[0110] 9/5 site (construct 9) encoding the recognition peptide with SEQ ID NO: 18 as follows:
V L R L G R A G A ↓ Y I F S S −9 −8 −7 −6 −5 −4 −3 −2 −1 +1 +2 +3 +4 +5
[0111] 8/5 site (construct 10) encoding the recognition peptide with SEQ ID NO: 19 as follows:
L R L G R A G A ↓ Y I F S S −8 −7 −6 −5 −4 −3 −2 −1 +1 +2 +3 +4 +5
[0112] 7/5 site (construct 11) encoding the recognition peptide with SEQ ID NO:20 as follows:
R L G R A G A ↓ Y I F S S −7 −6 −5 −4 −3 −2 −1 +1 +2 +3 +4 +5
[0113] 6/5 site (construct 12) encoding the recognition peptide with SEQ ID NO:2 as follows:
L G R A G A ↓ Y I F S S −6 −5 −4 −3 −2 −1 +1 +2 +3 +4 +5
[0114] 5/5 site (construct 13) encoding the recognition peptide with SEQ ID NO:21 as follows:
G R A G A ↓ Y I F S S −5 −4 −3 −2 −1 +1 +2 +3 +4 +5
[0115] Corresponding recombinant proteins as illustrated in FIG. 3A were expressed in E. coli, purified by Ni-NTA chromatography and subjected to the treatment with Pro39. Purified substrates were incubated with Pro39 for 60 minutes at 30° C. in molar ratio 20:1. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie Blue staining. The results are shown in FIG. 3B . The cleavage efficiency of the substrates 8-13 was compared to each other and to the control substrate 0. Two substrates—those containing recognition sites 10/5 and 6/5—were selected as results of this procedure. The cleavage efficiencies observed for corresponding recombinant proteins were somewhat lower than it was observed for control substrate (19/18), but still high enough to enable protease to process completely over than 10-fold molar excesses of substrate within one hour. It was demonstrated by use of the MALDI-TOF mass-spectrometry that cleavage specificity was also maintained for these truncates sites. It was also found that cleavage efficiencies for substrates containing constructs 9, 10, 11, and 13 (SEQ ID NO: 18, 19, 20 and 21, respectively) were significantly lower than those containing constructs 8 and 12 (SEQ ID NO: 1 and 2, respectively).
EXAMPLE 5
[0116] Identification of the role of +1 amino acid residue for cleavage activity and specificity. Construction of the optimized recognition sites.
[0117] As indicated in examples above Pro39 is capable to process a substrate containing construct 8 (10/5 site according to SEQ ID NO: 1) with no virus-specific sequence located downstream of the cleavage point. To determine if there is any requirement for +1 amino acid residue in substrate for Pro39 recognition and cleavage specificity the protease recognition sequence variants were constructed from synthetic oligonucleotides. FIG. 5A illustrates schematically substrates comprising oligonucleotide duplexes encoding for following cleavage site variants:
[0118] 15/Y site (construct 14) encoding the recognition peptide with SEQ ID NO: 22 as follows:
F G D F D D V L R L G R A G A ↓ Y −15 −10 −5 −1 +1
[0119] 15/A site (construct 15) encoding the recognition peptide with SEQ ID NO:23 as follows:
F G D F D D V L R L G R A G A ↓ A −15 −10 −5 −1 +1
[0120] 15/G site (construct 16) encoding the recognition peptide with SEQ ID NO: 24 as follows:
F G D F D D V L R L G R A G A ↓ G −15 −10 −5 −1 +1
[0121] 15/R site (construct 17) encoding the recognition peptide with SEQ ID NO:25 as follows:
F G D F D D V L R L G R A G A ↓ R −15 −10 −5 −1 +1
[0122] 15/S site (construct 18) encoding the recognition peptide with SEQ ID NO:26 as follows:
F G D F D D V L R L G R A G A ↓ S −15 −10 −5 −1 +1
[0123] 15/N site (construct 19) encoding the recognition peptide with SEQ ID NO: 27 as follows:
F G D F D D V L R L G R A G A ↓ N −15 −10 −5 −1 +1
[0124] 15/E site (construct 20) encoding the recognition peptide with SEQ ID NO: 28 as follows:
F G D F D D V L R L G R A G A ↓ E −15 −10 −5 −1 +1
[0125] 15/D site (construct 21) encoding the recognition peptide with SEQ ID NO: 29 as follows:
F G D F D D V L R L G R A G A ↓ D −15 −10 −5 −1 +1
[0126] Corresponding recombinant proteins were expressed in E. coli, purified by Ni-NTA chromatography and subjected to the treatment with Pro39. Purified substrates were incubated with Pro39 for 60 minutes at 30° C. in molar ration 20:1. Reaction products were analyzed by SDS-PAGE and visualized by Coomassie blue staining. It was demonstrated that the N-terminal amino acid residue of the protease recognition site can be substituted from Y (tyrosine, construct 14 according to SEQ ID NO: 22) to virtually any type of amino acids (S, G, R, N, D, E, C, M, L and A) except P with no change of protease cleavage specificity. At the same time anomalous electrophoretic mobility was detected for cleavage products with acidic amino acid residues (constructs 20 and 21 according to SEQ ID NO: 28 and 29, respectively) on its N-terminal position; MALDI-TOF analysis of these products clearly indicated that this is not due the unspecific cleavage of corresponding cleavage sites but due some change of mobility during SDS-PAGE. Most importantly, these experiments clearly indicated that if the native +1 amino acid residue Y (tyrosine) was substituted with glycine (G), serine (S ) or arginine (R ) residues (constructs 16, 17 and 18 according to SEQ ID NO: 24, 25 and 26, respectively) the cleavage site recognition and/or processing efficiently was significantly enhanced.
[0127] Oligonucleotide duplexes, encoding for following cleavage site variants were inserted into specially designed vector for expression of the recombinant substrates:
[0128] 10/S site (construct 22) encoding the recognition peptide with SEQ ID NO:30 as follows:
D V L R L G R A G A ↓ S −10 −5 −1 +1
[0129] 6/S site (construct 23) encoding the recognition peptide with SEQ ID NO: 31 as follows:
L G R A G A ↓ S −6 −1 +1
[0130] Corresponding recombinant proteins where expressed in E. coli, purified by Ni-NTA chromatography and subjected to the treatment with Pro39 as described above. It was demonstrated that recombinant proteins, containing these protease recognition sites, were processed specifically and with higher efficiency that recombinant proteins containing corresponding unmodified sites (result not shown). This finding indicates that modified protease recognition sites can be used in expression vectors instead of unmodified sites.
EXAMPLE 6
Demonstration of Pro39 Cleavage of Substrate Purified on Anti-E2Tag Antibody Conjugated Sepharose Resin
[0131] Recombinant protein TAP-DBD ( FIG. 10A ) was expressed in E. coli. Cells were lysed under native conditions. E. coli cell lysate was clarified and loaded onto pre-equilibrated anti-E2Tag antibody conjugated Sepharose resin. Substrate binding to resin was performed at 8° C. for 2,5 h. Subsequent washes of the column with buffer containing 1M NaCl and 100 mM NaCl removed contaminating proteins from column. Anti-E2Tag antibody conjugated Sepharose resin -bound substrate TAP-DBD was eluted under low pH conditions (0,5% acetic acid), pH neutralizing followed with 1 M Tris pH 9,5. Eluated substrate was incubated with Pro39 at 30° C. for various times. Reaction products were analyzed by Western Blot method using anti-E4Tag antibody 1E2. Goat anti-mouse IgG alkaline phosphatase conjugate was used as secondary antibody. Signals were visualized using bromochloroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). The results are shown in FIG. 10B and it can be clearly seen that the substrate is cleaved after incubation of 2 hours.
EXAMPLE 8
Celavage of Column-Bound Substrate by Pro39.
[0132] Recombinant protein TAP-DBD ( FIG. 10A ) was expressed in E. coli. Cells were lysed under native conditions. E. coli cell lysate was clarified and loaded onto pre-equilibrated anti-E2Tag antibody conjugated Sepharose resin. Substrate binding to resin was performed at 8° C. for 2,5 h. Subsequent washes of the column with buffer containing 1M NaCl and 100 mM NaCl removed contaminating proteins from column. Column-bound substrate was cleaved by incubating with Pro39 at 30° C. for 3 h. The flow through fraction was collected after cleavage. The cleaved product was eluted using buffer containing 1M NaCl. Uncleaved and still column-bound cleaved substrate was eluted using 2×Laemmli buffer. Cleavage products or eluted proteins were analyzed by Western Blot method using anti-E2Tag antibody ( FIG. 13 ) and anti-E4Tag antibody ( FIG. 12 ). Goat anti-mouse IgG alkaline phosphatase conjugate was used as secondary antibody. Signals visualized using bromochloroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT).The result clearly reveals that the pro39 works in column; it cleaves the matrix boind protien not only in solution but alos on the packed column.
[0133] A control experiment was performed in order to show that column-bound substrate is not cleaved without Pro39. Recombinant protein TAP-DBD ( FIG. 10A ) was expressed in E. coli. Cells were lysed under native conditions. E. coli cell lysate was clarified and loaded onto pre-equilibrated anti-E2Tag antibody conjugated Sepharose resin. Substrate binding to resin was performed at 8° C. for 2,5 h. Subsequent washes of the column with buffer containing 1 M NaCl and 100 mM NaCl removed contaminating proteins from column. Column-bound substrate was incubated with buffer without Pro39 under the same conditions at 30° C. for 3 h as with Pro39 above. The flow hrough fraction collected after cleavage. Elution using buffer containing 1M NaCl performed and elution with 2×Laemmli buffer followed. Reaction products were analyzed by Western Blot method using anti-E4Tag antibody 1E2 ( FIG. 14 ) and anti-E2Tag antibody ( FIG. 15 ). Goat anti-mouse IgG alkaline phosphatase conjugate as secondary antibody was used. Signals visualized using bromochloroindolyl phosphate/nitro blue tetrazolium (BCIP/NBT). As clearly seen from the blots of FIGS. 14 and 15 the substrate was not cleaved.
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The present invention discloses highly efficient novel recognition sites for Pro39 protease. The invention further provides a wide range of conditions for protein purification and modification with the novel recognition sites. The invention even further provides expression vectors for expression of fusion proteins in cells and method to purify fusion proteins.
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FIELD OF THE INVENTION
[0001] The invention relates to a method for coating articles, such as hockey sticks, baseball bats and tennis rackets, with a composition comprising particulate rubber. The invention also relates to articles so coated.
BACKGROUND OF THE INVENTION
[0002] Until relatively recently, most hockey sticks were made of wood. The manufacturing process of these most common and conventional hockey sticks provides laminations of wood with the bend, curve and shape of a blade surface followed by a wrap of fiberglass cloth or mesh. The blade surface is then dipped or coated with resin.
[0003] In use, the stick rides an ice surface ahead of a skater, which results in a grinding off of the resin on the heel of the blade surface. Moisture can then attack the laminations of wood with resultant de-lamination and structural failure of the blade. To prevent this, over the years hockey players have covered their sticks with covering materials, including tapes, adhesive or friction adhesive strips and rubber sleeves, to protect the blade surface and to provide a desired “feel” for a hockey puck. Tape has been the most common covering material. Nevertheless, tape has a number of drawbacks, including (a) a less than satisfactory “feel” due to insufficient resiliency of the tape material; (b) hockey tapes absorb a significant amount of water which increases the weight of the hockey stick and reduces the adhesion of the tape to the blade; (c) a less than desirable protection of the blade surface; and (d) the tape becomes undone and needs frequent reapplication or repair.
[0004] Recently, hockey sticks have been manufactured comprising composite and/or synthetic materials, such as KEVLAR, in part to address the durability problems associated with wood sticks and in part because they are lighter in weight and offer more predictable performance. Nevertheless, the blades of such sticks are extremely hard and stiff and do not provide the “feel” of wood. Accordingly, hockey players have resorted to taping the new composite and synthetic blades in the hope of regaining the familiar feeling of wood. However, tape applied as a covering to a synthetic or composite hockey stick blade has the same drawbacks as tape applied to a wood blade (see above).
[0005] A number of attempts have been made to address the aforementioned and other problems attendant to the use of wood or synthetic hockey stick blades. For example, U.S. Pat. No. 5,332,212 to Susi et al describes a hockey stick blade coated with an elastomeric polymer, such as polychloroprene, to provide a coating having characteristics that are designed to improve the “feel” of the blade. U.S. Pat.No. 6,364,793 to Valarik describes an adhesive layer comprising grains of corundum, ceramics, limestone, glass, rubber, textiles or plastics, that is applied to a hockey blade surface to reduce the slipperiness of the blade surface.
[0006] The prior art solutions have been less than satisfactory in that they do not provide a hockey stick blade with an optimal or desired “feel” for a hockey puck. Moreover, in the case of U.S. Pat. No. 6,364,793, the use of a pressure sensitive adhesive to adhere a composition comprising granular material to the blade of a hockey stick presents difficulties in bonding of the pressure sensitive adhesive to the blade surface. In addition, the need to formulate the composition comprising the granular material prior to adhering the composition to the blade surface limits the amount of granular material that can be incorporated into the composition. What has been needed is a covering for a hockey stick blade that is free of the drawbacks discussed above and that provides a desired “feel” for a hockey puck.
[0007] The inventor has now found that a hockey stick with a desirable “feel” for a hockey puck can be made by incorporating particulate rubber into a polymer matrix in situ on the surface of a hockey stick blade.
SUMMARY OF THE INVENTION
[0008] In accordance with the invention, there is provided a method for coating an article comprising:
[0009] (a) coating a surface of the article with an unsolidified resin composition that, upon solidification, forms a polymeric matrix on the surface of the article;
[0010] (b) applying particles of rubber to the coated surface prior to solidification of the resin composition; and
[0011] (c) causing or permitting the resin composition to solidify on the surface to form the polymer matrix with the rubber particles embedded therein.
[0012] In a preferred embodiment of the invention, the article is a hockey stick comprising a handle portion and a blade portion, with the coating being applied to the blade portion of the hockey stick.
[0013] In another preferred embodiment, the resin composition comprises a curable resin and a curing agent, wherein the curable resin comprises at least one resin selected from the group consisting of a urea resin, a phenol resin, an imide resin, an epoxy resin and a vinyl ester resin. The method comprises a step of mixing said curable resin and said curing agent together prior to said coating step (a).
[0014] In a further preferred embodiment, the method comprises pressing the rubber particles onto said surface after said step (b) and prior to said step (c). The method also can include a step of forming a design or alphanumeric characters in the rubber particles applied to the surface in step (b) prior to said pressing, and/or forming ridges on the surface prior to said pressing.
[0015] There is also provided in accordance with the invention a hockey stick comprising a handle portion and a blade portion, the blade portion having a surface comprising a particulate rubber coating embedded in a cured polymer matrix, the particulate rubber comprising rubber that can pass through a 20 mesh minus screen. In a preferred embodiment, the particulate rubber particles cover an area of the surface of between 15-35 square inches.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] A fuller understanding of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings in which:
[0017] [0017]FIGS. 1 a - c diagrammatically depict steps of a method used for coating an article according to the present invention;
[0018] [0018]FIG. 2 is a diagrammatic view showing a pressing tool used to press rubber particles onto the surface of a hockey stick blade according to one aspect of the present invention; and
[0019] [0019]FIG. 3 is a sectional view of a blade surface coated with a particulate rubber composition according to the present invention.
DETAILED DESCRIPTION
[0020] In a preferred embodiment of the invention, a curable resin composition is prepared comprising a curable resin and a curing agent that reacts with the curable resin to promote curing thereof. A curing catalyst may optionally be added to accelerate the reaction between the curable resin and the curing agent. Rubber in the form of granules or particles is added to the curable resin composition after the curable resin and curing agent have been mixed together and the mixture has been applied to the blade of a hockey stick, but before curing of the resin has been effected. It is important that the rubber particles or granules be added to the mixture before the curing of the resin has been completed so that the rubber particles or granules can become embedded in a cured polymer matrix once the curable resin has been cured.
[0021] This sequence of steps is shown in FIGS. 1 a - c , wherein FIG. 1 a shows the mechanical mixing with a stirring tool 4 of the components of a curable resin composition 2 comprising a curable resin and a curing agent. FIG. 1 b shows the application of the mixture to the blade surface 6 of hockey stick 8 by means of a spread tool 10 . Alternatively, the blade surface 6 may be dipped into the resin composition, with prior masking of those portions of the blade surface, if any, for which the application of resin composition is not desired. FIG. 1 c shows the pressing of the blade surface 6 into granular rubber 12 so that the granular rubber may become incorporated into the resin composition on the blade surface.
[0022] In a preferred embodiment of the invention, the stirring tool 4 can comprise means for creating a texture or pattern on the blade surface. For example, the resin composition can be applied to the blade surface with a putty knife with jagged edges that produce evenly spaced ridges in the resin mix. Texturing tools can range from corrugated surfaces to cross-hatched or ridged surfaces accomplished through the use of suitable utensils, such as kitchen cooking utensils. The formation of ridges or crosshatching in the blade surface is also possible and may be used to aid in incorporation of the granular rubber into the resin mix.
[0023] [0023]FIG. 2 shows a further preferred embodiment of the invention wherein a stamp or press tool 14 is used to press the granular rubber 12 into the resin composition on the blade surface 6 in the direction shown by arrows 20 . In this step, the tool 14 can be used to press or stamp any of a variety of patterns into the granular rubber while the rubber is being pressed into the resin composition on the blade surface. For example, the tool 14 may be used to create a desired design or logo on the blade surface. Alternatively, a design or logo can be applied to the granular rubber with spray paint using a stencil or any other suitable technique. FIG. 3 shows a logo 16 that may be cut in or painted on granular rubber 12 on blade surface 6 .
[0024] The resin composition of the invention is preferably one comprising a curable or reactive resin wherein the granular rubber can adhere to the curable resin composition prior to the resin being cured, and wherein the granular rubber becomes embedded in a polymer matrix formed upon curing of the curable resin. The curable or reactive resin of the invention can, for example, comprise one or more resins selected from the group consisting of urea resins, phenol resins, imide resins and vinyl ester resins, with epoxy resins and polyol resins presently being preferred and epoxy resins being the most preferred.
[0025] Epoxy resins constitute a broad class of polymeric materials characterized by epoxide groups which are cured by reaction with certain catalysts or curing agents to provide cured epoxy resin compositions with desirable properties. One class of curing agent is the amines. The most commonly used amine curing agents are aliphatic amines such as diethylenetriamene, trietheylenetetramine and the like, and/or polyoxyalkylene polyamines, such as polyoxypropylenediamines and triamines. Epoxy resin compositions comprising a curable epoxy resin and a curing agent that are usable in the present invention are described, for example, in U.S. Pat. No. 6,417,316 to Wiesendanger et al and U.S. Pat No. 4,178,426 to Waddill. These patents are incorporated herein by reference.
[0026] Curing agents for polyol resins include isocyanates, and a preferred polyol/isocyanate curable resin system for use in the invention is a product marketed under the trademark AMERAGUARD AG 2000 manufactured by Armaguard Coatings Inc. of Alberta, Canada. This product is a two-component elastomer spray system comprising a polymeric isocyanate (polymeric diphenylmethane 4, 4 diisocyanate) as a first component and a polyether polyol as a second component. The product may be applied to the surface of a hockey stick blade (either wood or synthetic) as a heated spray composition. Resins within the heated spray composition will cure upon cooling. Accordingly, the blade surface treated with the heated spray should be immediately immersed in pulverized rubber such that, upon cooling of the resin composition, the rubber binds to and becomes embedded in the cured resin.
[0027] The rubber particles for use in the invention may be natural or synthetic rubber particles. The particles are preferably finely ground rubber known as “rubber dust” that has been, for example, reclaimed from used rubber products and, in particular, from vehicle tires by processes that are well known in the art. For example, U.S. Pat. No. 5,299,744 to Garmater and U.S. Pat. No. 6,425,540 to Morris et al (the contents of which are incorporated by reference) describe apparatus and methods for grinding of rubber material to form finely ground rubber particles. The inventor has achieved superior results using rubber dust reclaimed from recycled tire shavings that have been granulated and passed through a twenty (20) mesh minus screen. Twenty mesh minus is a term of art indicating that the dust will pass through a one-square-inch mesh of 20 holes horizontally by 20 holes vertically. For use in the invention, it is preferred that the rubber dust particles be able to pass through at least a five (5) mesh minus screen. The rubber dust particles would preferably not be so small as to pass through an eighty (80) mesh minus screen. Most preferred dust particles for use with the present invention would be able to pass through a ten (10) mesh minus screen but would not be able to pass through a thirty (30) mesh minus screen.
[0028] Larger particles than the preferred particles described above can and have been successfully applied to a hockey stick blade by the inventor. It may be appreciated in this regard that the grain, size and type of the rubber particles will depend on the surface to which they are applied and the desired “feel” to be imparted to the article coated with the rubber particles. The surface to be coated is not limited and requires only that the resin composition applied to the surface be one that, upon solidification or curing, will (a) adhere to the surface, and (b) bind the rubber particles. For example, the invention may be used with any of the materials that are presently used in hockey sticks, including wood, aluminum and composite materials such as fiber/resin composites. Such fiber/resin composites may include epoxy resins and graphite or aramid fibers, such as KEVLAR brand aramid fibers sold by E.I. DuPont de Nemours and Company of Wilmington, Del.
[0029] The coated hockey stick blade produced by the methods described above will comprise a blade surface having a coating of particulate rubber incorporated into a cured polymer matrix. The particulate rubber will preferably cover substantially the entirety of the striking surface of the blade without gaps between the rubber particles. Preferably this will comprise an area of between about 15-35 square inches on one or both sides of a hockey stick blade. This will insure that, when the coated hockey stick blade is used to strike a hockey puck, a particulate rubber-containing surface of the blade will be available to make contact with the puck. This will provide the user of the hockey stick blade with a desirable “feel” for the hockey puck. It will also serve to provide for a durable protection of the blade surface.
EXAMPLES
Example 1
[0030] 20 mesh minus rubber dust particles refined from recycled tire shavings were obtained from Community Tire Company in St. Louis, Mo. A five (5) gallon pail was filled with this rubber dust. A hockey stick blade was coated with a heated spray of AMERAGUARD AG 2000 and the stick blade was immersed in the pail. The spray was allowed to cool and cured in about 30-45 seconds. The stick with a coating of the rubber dust particles was ready to use in a matter of minutes after the spray treatment.
Example 2
[0031] A common household two-component epoxy paste of the brand name PC-7 made by Protective Coating Company Corporation of Allentown Pa. was purchased. The two-components were mixed together and applied with a spreading tool to a hockey stick blade. The rubber dust particles described in Example 1 were immediately pressed into the epoxy coating on the surface of the blade and the epoxy resin was allowed to cure for 8-10 hours. The treated hockey stick was then tested in play and was found to have superior “feel” for a hockey puck.
[0032] Although the invention has been described above with particular reference to a hockey stick blade, it may readily be appreciated that the methods and coatings of the invention are not so limited and may be applied to articles used in other sports and in other endeavors. These and other modifications and changes can be made without departing from the scope of the invention as defined by the following claims.
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A method for coating an article, including the steps of: (a) coating a surface of the article with an unsolidified resin composition that, upon solidification, forms a polymeric matrix on the surface of the article; (b) applying particles of rubber to the coated surface prior to solidification of the resin composition; and (c) causing or permitting the resin composition to solidify on the surface to form the polymer matrix with the rubber particles embedded therein. Also, an article coated by the method. In a preferred embodiment, the article is a hockey stick.
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FIELD OF THE INVENTION
[0001] The present invention relates in general to joining non-metallic and metallic components and in particular to rigid attachment of quartz and ceramic components to metal.
BACKGROUND OF THE INVENTION
[0002] The proper design and function of many devices requires rigid bonding of diverse materials. In many cases a brittle material, such as quartz or a ceramic is bonded to a metal. Adhesives can be employed for this purpose but do not allow for detachment of the two materials in the event that adjustment or maintenance is required. The use of metal clamps is unsatisfactory because of the danger of breakage of the brittle material. In addition, most metals have a very different coefficient of thermal expansion than quartz or ceramics. Thus, a clamp that is tight at one temperature can be loose at a higher temperature.
[0003] Accelerometers are devices that measure acceleration in many applications. Gravimeters (or gravity meters) are extremely sensitive and precise accelerometers that measure variations of the earth's gravitational field. Modern versions of such gravimeters can achieve relative accuracies of the order of a few micro Gals (10 −8 m/s 2 ), i.e. a few parts in 10 −9 of g, the earth's mean gravitational attraction.
[0004] A full review of the design of gravimeters, both historical and current, is found in the volume Gravimetry, authored by Wolfgang Torge, Walter de Gruyter Press, Berlin-New York, 1989. Numerous designs of gravimeters have been proposed and built over the past 100 years or more. Most of these have been based on deflection, by changes in gravity, of a proof-mass that is supported by an elastic spring member. The elastic spring member can take the form of a helical spring (e.g. LaCoste-Romberg, Worden and Scintrex, as described in the Torge reference, pages 232-236) or a torsion wire (e.g. Mott-Smith, Norgaard, and Askania—Torge pages 227-228). Both metal and quartz have been employed for the material of the elastic spring in these various gravimeters. Each material has merits and shortcomings with respect to ease of manufacture and stability with time, with changes in temperature and with shock.
[0005] On the whole, quartz appears to be the preferable material for the elastic spring, due to the inherent material properties. Quartz is highly elastic and shows little mechanical hysteresis after extension or torsion. In thin fibres for springs or hinges (for highly sensitive sensors), quartz has very high strength. This permits the use of quartz fibres for springs or hinges in unclamped mode in rough field use, with no deleterious effects. This is shown in, for example, “The potential application of the Scintrex CG-3m gravimeter for monitoring volcanic activity: results of field trials on Mt. Etna, Sicily”, by G. Budella and D. Carbone, Journal of Volcanology and Geothermal Research, 76 (1997)199-214. Because of its' elasticity, quartz is resistant to irreversible offsets caused by sudden shock, known as “sets”. On the other hand, thin metal fibres are very prone to such sets. Also, quartz has negligible magnetic susceptibility, and thus is unaffected by strong magnetic fields, unlike ferrous metals. Quartz is also a good insulator and facilitates the electrical isolation of metallic components that is necessary in the design and proper functioning of some gravimeters. From a manufacturing standpoint, a quartz-based gravity sensor is, in some respects, easier to construct, as complex forms and attachments of other quartz components may be achieved by heat forming.
[0006] A problem arises, however, when a quartz-metal joint is required, for example to support the quartz structure, or to attach a metal component to it. It is important to the proper functioning of the gravimeter that such attachments be rigid and stable, allowing no relative movement of the quartz-metal members, while avoiding stress on the quartz during clamping, causing the quartz to shatter. Glue or mechanical clamps are two approaches commonly used to solve this problem
[0007] Mechanical clamps are complex and relatively large, which makes them unsuitable for miniature components. Also it is difficult-to-distribute the required clamping force over sufficient contact surface area to prevent damage to the quartz component. This problem was clearly stated in the article “Tidal to Seismic Frequency Investigations with a Quartz Accelerometer of New Geometry”, by Barry Block and Robert D. Moore, Journal of Geophysical Research, 75, No.8, Mar. 10, 1970. To achieve mechanical support of the quartz torsion fibre, Block and Moore ground the quartz to provide flat surfaces for clamping to metal components without slippage. It was determined that the surfaces had to be ground fiat to within 12 microns to mate precisely with the corresponding metal surface. To reduce the possibility of breakage of the quartz, a layer of soft aluminum foil cushioned each clamp. Insertion of the soft aluminum foil reduced the rigidity and stability of the resulting joint.
[0008] A second means of creating such joints is the use of an epoxy cement or other type of adhesive. This approach has a number of disadvantages, however. At the microscopic level it does not form a stable and totally elastic bond. It is non-reversible, and does not allow for adjustment, alignment or later maintenance or repair. Epoxies also exude vapours, which contaminate the atmosphere in the gravity sensor and may adversely affect the performance of the gravimeter.
[0009] An additional problem that arises through the use of either metal clamps or cements to effect a bond is that there is a large difference in the coefficients of thermal expansion between most metals and quartz or ceramics. A joint created at one ambient temperature may become loose at a higher temperature.
[0010] There is a need for a means for rigid and stable attachment of quartz to metal in miniature quartz-element accelerometers such as gravimeters, which does not have the problems associated with mechanical clamps or glue. It is desirable that the attachment be reversible to allow detachment for the purpose of assembly, adjustment or maintenance.
[0011] A technique of attachment of a metal part to another metal part by thermal means, commonly known as “shrink-fit”, is well known in the art (e.g. see Timoshenko, S. Strength of Materials 3 rd edition 1956-68 Van Nostrand. P36, 205). In practice, this technique is usually carried out using only metal parts. The present invention exploits the difference in the coefficients of thermal expansion between the two materials being joined. In joining quartz or ceramics to metal, the two materials have very different coefficients of thermal expansion. It is this difference that presents difficulties in effecting joints through other means, such as clamping, or through the use of adhesives. Joints created in accordance with this invention are very simple in design, so are suitable for miniaturization.
SUMMARY OF THE INVENTION
[0012] In one aspect of the present invention, there is provided a method of attaching a first member of one of quartz and a ceramic to a metal member. The method includes creating a hole in the metal member; the hole being smaller in size than the size of the first member over a temperature range, heating the metal member to a temperature sufficient to expand the hole to allow insertion of the first member in the hole, inserting a portion of the first member into the hole, and cooling the metal member to form a joined structure of the first member and the metal member.
[0013] In another aspect of the present invention, there is provided a joined structure including a metal member having a hole therein and a first member of one of quartz and a ceramic inserted in the hole. The metal member exerts a compressive stress on the first member, over a temperature range.
[0014] In one aspect, the present invention provides a means of creating a rigid, reversible bond between quartz and metal, without the use of clamps or adhesives.
[0015] The present invention utilizes the differences between the coefficient of thermal expansion of pure fused silica and many ceramics and that of most metals. By utilizing this difference in coefficients, a thermal-based bond is created between the metal and quartz or ceramic without the complexities and detrimental effects associated with metal clamps and glues.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will be better understood with reference to the following description and the drawings, in which:
[0017] FIG. 1 is a partial sectional side view of a quartz member being joined with a metal member, in accordance with an embodiment of the present invention;
[0018] FIGS. 2A and 2B are partial section side views of the quartz member being joined with the metal member of FIG. 1 , showing a preferred geometry of the metal member;
[0019] FIGS. 3A and 3B are partial sectional side views of the quartz member being joined with the metal member of FIG. 1 , showing another preferred geometry of the metal member; and
[0020] FIG. 4 is a schematic diagram of a gravimeter in which a quartz member and metal member, joined in accordance with the embodiment of FIG. 1 , are employed for parts thereof.
[0021] FIG. 5 is a perspective view of a portion of the gravimeter of FIG. 4 , drawn to a larger scale.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] For ease of illustration only, the present discussion is directed to improvements in the design of quartz element gravimeters. It will be understood that the present invention is not limited to quartz element gravimeters, however. It will be appreciated that ceramic-elements can also be used and that the present invention is also applicable to accelerometers used for other purposes such as seismometry.
[0023] Table 1, included below, includes a list of coefficients of thermal expansion of quartz, ceramics and metals that are commonly employed in the design of various devices. Clearly there is at least an order of magnitude difference in the coefficient of thermal expansion between quartz and all the metals that are commonly employed in the construction of a typical gravity sensor. There is also a significant difference between the coefficients of thermal expansion for ceramics and most metals, although to a lesser degree than the difference between the coefficients of thermal expansion of quartz and metals.
TABLE 1 Coefficient of Thermal Expansion of Materials Material Coefficient (ppm/° C.) Quartz 0.6 Ceramics 3-5 (typical) Copper 16.7 Aluminium 23.8 Gold 14.3 Stainless steel 10.5 Invar temperature dependent (typically 1-2 (at 20° C.) to 16 (at 350° C.))
[0024] Referring first to FIG. 1 , a metal member is shown and indicated generally by the numeral 10 . The metal member 10 is machined to create a hole 14 for attachment of a quartz member 12 , also referred to as a quartz rod. A heat source 13 is provided for increasing the temperature of the portion of the metal member 10 that surrounds the hole 14 .
[0025] FIGS. 2A and 2B illustrate the quartz member 12 being joined with the metal member 10 , showing a preferred geometry of the metal member 10 . The metal member 10 is, machined such that the mouth of the hole 14 includes a taper 15 . FIGS. 3A and 3B illustrate the quartz member 12 being joined with the metal member 10 , showing an alternative geometry of the metal member 10 . In this geometry, the metal member 10 includes a tapered portion 16 , such that the metal member 10 is tapered towards the mouth of the hole 14 .
[0026] In each of FIGS. 1, 2 and 3 , the quartz member 12 is substantially cylindrical, in the form of a rod with circular cross-section of uniform radius. The hole 14 is machined in the metal member 10 such that the diameter of the hole 14 is rigidly controlled to be a predetermined amount less than the diameter of the quartz member 12 , over a range of operating temperatures for a sensor. The metal member 10 is then heated by the heat source 13 . Suitable heat sources include a flame, heating in an oven, or other suitable means. The metal member 10 is heated to a temperature well above the operating temperature range of the sensor, to the point where expansion of the metal member 10 allows the quartz member 12 to be inserted into the hole 14 . The quartz member is then inserted into the hole 14 of the metal member 10 . On cooling of the metal member 10 , the metal member 10 shrinks and the quartz member 12 is firmly clamped by the metal member 10 , thereby providing a rigid joint. If desired, the joint is heated, causing expansion of the metal member 10 to allow the quartz member 12 to be removed. Although both the quartz member 12 and the metal member 10 are heated to the same temperature, the metal member 10 expands more than the quartz member 12 . Thus, the diameter of the hole 14 increases more than the diameter of the quartz member 12 and, at a sufficiently high temperature, the quartz member 12 is withdrawn from the hole 14 of the metal member 10 .
[0027] For some applications it may be a more expedient and better controlled procedure to heat both the quartz and metal member to a common temperature in order to make the joint. In this case, the common temperature that the quartz and metal members are heated to, is the same high temperature used for the removal of the quartz member.
[0028] The following examples are submitted to further illustrate embodiments of the present invention. These examples are intended to be illustrative only and are not intended to limit the scope of the present invention.
EXAMPLE 1
[0029] In the present example, a quartz member 12 is joined to a copper metal member 10 . The quartz member 12 has a diameter of X, and the hole 14 drilled in the metal member 10 has a diameter of 0.998X. The copper metal member 10 is heated slightly more than 120° C. above ambient temperature, causing an increase in the diameter of the hole 14 by 0.2% and the quartz member 12 is then inserted into the enlarged hole 14 . To release the quartz member 12 from the copper metal member 10 , the temperature at the joint is heated to a slightly higher temperature, namely above 125° C. above ambient temperature. The difference in temperature accounts for the fact that both the quartz member 12 and the metal member 10 are heated, and that the difference in thermal coefficients of expansion between these two materials is about 16 ppm/° C.
EXAMPLE 2
[0030] In this example, Invar is employed. Invar is an alloy of iron metal with unusual thermal properties. As shown in Table 1, invar has a very low coefficient of thermal expansion (˜1-2×10 −6 ) in the usual range of ambient operating temperatures (0° C. to +45° C.). This is very desirable for stable operations. However, when heated the coefficient of thermal expansion rises, increasing ten fold when the temperature reaches 400° C., which thus allows the invar to be joined to quartz and ceramic components, in accordance with an embodiment of the present invention.
[0031] In constructing the quartz-metal joint shown in FIG. 1 , it is desirable to inhibit undue tensile stress gradients on the surface of the quartz member 12 when the metal member 10 contracts in order to avoid breakage of the quartz member 12 . The maximum tensile stress gradient on the surface of the quartz member 12 occurs at the open end of the hole 14 , between the compressed and non-compressed portions of the quartz member 12 . The geometries shown in FIGS. 2 and 3 are illustrative of two means of reducing tensile stress gradient on the surface of the quartz member 12 . In FIG. 2A , this is accomplished by machining a smoothly tapered mouth of the hole using the taper 15 , where the diameter at the mouth of the hole is equal to the diameter of the quartz member 12 at a typical operating temperature. Thus, the mouth of the hole 14 is greater in diameter than that of the quartz member 12 when the metal member 10 is heated. When the quartz member 12 is inserted and the metal member 10 cools ( FIG. 2B ), there is no stress on the quartz member 12 at the mouth of the hole 14 . The diameter progressively and smoothly changes along quartz member 12 into the hole 14 and thus reduces the tensile stress gradient on the surface of the quartz member
[0032] In FIG. 3A , the metal member 10 is formed to include a tapered portion 16 about the mouth of the hole, the diameter of which is finely tapered to the diameter of the hole 14 . The metal member 10 is heated and the quartz member 12 is inserted into the hole 14 , as described above. As the metal member 10 cools and contracts ( FIG. 3B ), the lip of the hole 14 is deformed outwardly (in a bell-like manner), thereby reducing the tensile stress gradient on the surface of the quartz member 12 in the region of the mouth of the hole 14 .
[0033] FIG. 4 is a schematic diagram of a gravimeter 30 in which the quartz member 12 and the metal member 10 , joined in accordance with the embodiment of FIG. 1 , are employed for parts thereof. The gravimeter 30 includes a rigid quartz frame 17 supporting a gravity sensing device including a quartz spring 18 , a quartz hinge 19 , a proof-mass 20 , supported by a support 23 connected to both the spring 18 and the hinge 19 . Two metal plates 21 , 22 are disposed on each side of the proof-mass 20 and are each supported by a respective support 24 , 25 . Quartz to metal joints are employed at several locations including: the support 23 to the proof-mass; the supports 24 , 25 to the supporting quartz frame for the metal plates 21 , 22 ; the point 26 at which the sensor assembly is attached to the metal enclosure 27 , and at supports for stops 28 , which are metal stops designed to limit the range of movement of the proof-mass 20 . In order for the gravity sensor to operate properly, the proof-mass 20 is electrically conductive, preferably made of metal. This proof-mass 20 acts as one plate of each of two capacitors, with plates 21 and 22 respectively as the other plates of these capacitors. The two capacitors are measured in a capacitance bridge and act as a sensitive method of sensing the position of the proof-mass 20 . The imbalance signal from the capacitance bridge is rectified to create an electrostatic feedback force, which is applied across the outer metal plates 21 , 22 to restore the proof-mass 20 to a horizontal position. To sense the position of the proof-mass 20 with sufficient precision in order to have a resolution and stability of the order of 10 −9 g, the geometry of plates 21 and 22 and the proof-mass 20 must be established and maintained to the same order, effectively a few A°.
[0034] FIG. 5 shows a perspective view of a portion of the gravimeter, according to one embodiment of the present invention, showing the positioning of the outer metal plates 21 , 22 in greater detail. As shown, the outer metal plates 21 , 22 are rigidly positioned, in parallel juxtaposition, through the supports 24 , 25 , which are quartz and attach to the frame 17 ( FIG. 4 ) of the gravimeter. In this embodiment each of the outer metal plates 21 , 22 is joined to both quartz supports 24 , 25 , thus providing a high level of stability in the relative positions of the two plates 21 , 22 . The support 23 is also a quartz member and is attached to the metal proof mass 20 through an edge that has an increased thickness to accommodate a hole, into which the quartz member 23 is inserted.
[0035] Thus, the design of the gravimeter 30 employs the junction of quartz to metal at several locations, e.g. at the support 23 to the proof-mass 20 , at the supports 24 and 25 for the plates 21 and 22 , at the point 26 , which is the basic point of attachment of the whole sensor assembly to the metal enclosure 27 , and at the supports for the stops 28 , which limit the range of travel of the proof-mass 20 . Moreover, it is important to inhibit long-term drift or shock-induced slippage. The quartz member 12 to metal member 10 joint of the present embodiment enables these conditions to be met.
[0036] For the purpose of the present invention, the quartz member 12 of the joint is of uniform diameter and of circular cross-section, for the optimum function. If the basic quartz structure is not in this desired form, a section of right-circular quartz cylinder is fused to the quartz structure at the desired connection point, thereby providing the circular cross-section quartz member 10 for the joint.
[0037] Although the present invention is described as having particular application to the design and construction of gravimeters incorporating quartz elastic members, it is equally applicable to quartz-metal joints, and ceramic-metal joints in other accelerometers and devices for other applications. It should be noted that the difference in the coefficient of thermal expansion between ceramics and metals is less than that between quartz and metals (e.g. 13 vs. 16×10 −6 ). Thus, the temperature to which the metal member is raised for release of the ceramic rod is proportionately higher than the temperature to release the quartz in the case of the quartz-metal joint.
[0038] It will be understood that the present invention has been described by way of example and modifications and variations to the embodiments described herein may occur to those skilled in the art. All such modifications and variations are believed to be within the sphere and scope of the present invention.
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A method of attaching a first member of one of quartz and a ceramic to a metal member. The method includes creating a hole in the metal member, the hole being smaller in size than the size of the first member over a temperature range, heating the metal member to a temperature sufficient to expand the hole to allow insertion of the first member in the hole, inserting a portion of the first member into the hole, and cooling the metal member to form a joined structure of the first member and the metal member.
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FIELD OF THE INVENTION
This invention relates to a suppressed carrier signal receiver and, in particular, to an improved AGC circuitry in the suppressed carrier signal receiver for preventing false lock in such a receiver.
PRIOR ART
In the early phases of the development of the suppressed carrier signal receiver the now well known Costas loop was extensively used. In such a receiver a noncoherent or total power AGC control apparatus was employed usually to provide the loop gain control. The control apparatus includes means for deriving an AGC output from one channel of the Costas loop, for example, the in-phase channel by detecting the incoming signal with a square law detector and means for comparing the resulting output with an AGC reference signal to provide the AGC feedback control signal. The signal detected in the in-phase channel contained not only the signal but also the noise contributed by the thermal noise of the receiver. However, such prior art AGC control circuitry was found still susceptible to the false lock. k
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved receiver of the type adapted to receive suppressed carrier signals.
It is another object of the present invention to provide an improved receiver of the type adapted to receive suppressed carrier signals with an improved AGC circuitry that prevents false locking of the receiver.
The foregoing and other objects of the present invention are obtained by providing a network in the Costas loop that includes means for deriving a noise estimate signal from one channel of the Costas loop and means for subtracting the noise estimate signal from the data and noise signal combination detected from the other channel and providing an automatic gain control signal that prevents false locking of the receiver.
The foregoing and other objects and features of the present invention will be more clearly apprehended from the following detailed description of an illustrative embodiment in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 shows a prior art functional block diagram of a receiver of the type with a Costas loop adapted to receive suppressed carrier signals.
FIG. 2 shows loop gain and in-phase channel response characteristics.
FIG. 3 shows a block diagram of a suppressed carrier receiver.
FIGS. 4A-4D show response characteristics of the suppressed carrier receiver that illustrate false lock condition.
FIGS. 5-6 show various response characteristics of the prior art receiver.
FIG. 7 shows the AGC receiver of the type with the Costas loop shown in FIG. 1 modified to provide the automatic gain control signal that prevents false locking of the receiver in accordance with present invention.
FIG. 8 shows response characteristics of the receiver with the inventive AGC circuitry.
DETAILED DESCRIPTION
In the conventional suppressed carrier receiver with the Costas loop, total power AGC signal is developed to provide the AGC control before and after the acquisition of the incoming signal. Such a prior art apparatus is illustrated in FIG. 1. The receiver is provided with a mixer 10, and an IF amplifier detector 11. The IF input is mixed with a voltage controlled oscillator (VCO) 12 output. The mixer output is amplified and decomposed into the in-phase and quadrature components by multipliers 13 and 14 under the control of a reference oscillator 15 for the in-phase channel and under the control of the oscillator 15 output after it is 90° phase shifted by a phase-shifting for the quadrature channel circuit 17. The decomposed signals in the respective channels are filtered through low pass filters 21 and 22 disposed in the two channels.
The in-phase of I channel signal (Cos E) output is used as the data output via output terminal 23 and is also used to obtain an AGC output feedback control signal using a square law detector 31 and AGC comparator 32. The quadrature phase or Q channel signal (Sin E) is similarly processed through a square law detector 33, an RC filter 35 and a threshold reference comparator 37 to provide a lock out signal.
As schematically illustrated, the in-phase and quadrature-phase signals are also used to obtain the voltage controlled oscillator (VCO) signal using an IQ multiplier 39, a loop filter 40 and the VCO 12 in a conventional manner. The VCO output is then applied to the mixer 10 via a multiplier 41 in a conventional manner.
As illustrated above, according to the prior art, the total power AGC control method utilizes the total power output which represent the combined power of signal and noise power appearing in the in-phase (Cos E) branch to derive the AGC feed back control signal to the IF. During the signal acquisition, the signal acquired is composed of the demodulated bi-phase data modulated by the beat frequency in the acquisition loop made up of the in-phase channel and the AGC output feedback to the IF amplifier 11. After acquisition, the gain control is provided by the data signal plus noise as follows. The signal plus noise estimate is provided by the square law detector 31 whose DC output is filtered and amplified to establish the desired AGC loop parameters.
More specifically, the lock detection is obtained by estimating the total power in the quadrature channel (Sin E) as follows: first by estimating the total power by the use of square law detector 33 in the quadrature channel and then subjecting the output of the square law detector to the RC filter circuitry 35 and then comparing the output to a preset threshold reference signal using a conventional comparator 37. When the loop is out of lock, the signal in the quadrature channel (Sin E) is substantially the same as the signal in the in-phase channel, except for its phase which is quadrature removed from the in-phase signal.
When the lock is achieved the beat note and data modulation no longer exists in the quadrature channel. Consequently only the small noise component produces an output from the square law detector in the quadrature channel. The comparator 37 provides the inlock and out of lock signal by comparing the threshold reference signal to the output of the square law detector. By suitable design of the comparator and provision of the suitable reference voltage, the output of the comparator 37 is made to present one level of DC potential to represent out of lock condition and another level of potential to represent in lock condition.
In obtaining the automatic gain control signal the amplifier 32 compares the output of the square law detector 31 with an automatic gain control reference signal. In a pg,6 conventional manner RC filter may be used to limit the lock detection response time and thereby smooth out the detected noise signal at the output of the comparator 32.
Since the total power AGC method utilizes signal plus noise estimation it causes inherent signal and loop gain suppression at the low signal to noise ratios near threshold as illustrated in the normalized voltage level versus signal characteristics shown in FIG. 2. FIG. 2 shows measured total power AGC characteristics; in the upper curve, the nature of the signal component of the in-phase channel is shown; in the lower curve, the nature of the loop gain component of IQ multiplier is shown. Ordinarily this signal suppression can be accommodated in the same manner as limiter suppression in a conventional receiver. However, the bandwidth expansion and loop gain increase at stronger signal present problems to the Costas loop in that they tend to false lock on the clock components.
FIG. 3 and FIGS. 4A-4D illustrate, in a simplified form, the process by which a false lock takes place in a conventional prior art suppressed carrier receiver. In an ideal case, as shown in FIG. 3, if an ideal detector 51 of nonlinear element character can be found, it could be used to obtain the carrier, f c , (FIG. 4A) from the suppressed carrier input (FIG. 4B). However, in fact, such an ideal detector is not available. So instead, a suitable bandpass filter 52 used generally to band limit the input signal to obtain a band limited output (FIG. 4C) and then the band limited output is processed through a nonlinear element detector of some kind to obtain the carrier. The detected output (FIG. 4D), however, contains spectral components, f c -f b , f c -1/2 f b , f c +1/2 f b , f c +f b , which are multiples of the half of the clock rate of the data. As illustrated in FIG. 4D, these spectral components, that are related to the carrier, f c , and the bandwidth, f b , of the receiver render the conventional receiver, susceptible to false lock, i.e., the receiver tends to lock onto a spectral component other than the carrier, f c .
Thus, it is evident that the mechanism by which a false lock is generated is a subtle one. In short, for a suppressed carrier signal, the nonlinear operation of squaring or multiplication reproduces the desired carrier component alone only if the inputs to the nonlinear device are not band limited. The magnitude of the false lock components, f c -f b , f c -1/2 f b , f c +1/2 f b , f c +f b , will be a function of the ratio of Costas low pass filter bandwidth (B c ) to data rate (F b ).
For the false lock to pose a problem for the suppressed carrier detector it is found that two criteria must be satisfied. First the receiver must sweep through the false lock frequency during its acquisition. Secondly, the receiver loop gain must be sufficiently high to allow acquisition at a certain desired sweep rate.
For a proposed acquisition range, for example, of +Δf kHz, the maximum frequency uncertainty during acquisition is 2Δf kHz. Thus, any data rate or half data rate component below this frequency is a potential false lock candidate.
The false lock components can be characterized by loop gain relative to the desired signal and a false lock loop bandwidth, β FL . Experimentally, a false lock component loop gain was measured using the configuration shown in FIG. 1 and they were found as illustrated in FIG. 5 wherein the vertical axis repesents in normalized form, relative gain and the horizontal line represents the bandwidth to data rate (B c /F b ) ratio. From FIG. 5, the effective loop bandwidth for both clock and 1/2 clock components for various ratios of pre-multiplier filter bandwidths to data rates (B c /F b ) can be computed by the following equation.
β FL = β LA G R
β fl = false lock loop bandwidth
β LA = Acquisition loop bandwidth
G r = relative loop gain of false lock component
To determine the loop gain margin for each case, it is then only necessary to compute ##EQU1## where β FL = effective false lock loop bandwidth β m = minimum possible bandwidth for acquisition at the desired sweep rate.
G m = False lock margin
β m will occur when the loop phase error is 45° (0.78 rad) and can be computed by ##EQU2## R s = sweep rate E = phase error in radians = 0.78 radians.
The loop gain margin (vertical axis) has been computed for both 1/2 clock and clock components and is plotted in FIG. 6 against the bandwidth to data rate ratio, B c /F b .
It is apparent from these results that the optimum premultiplier bandwidth must be a trade off between maximum signal-to-noise ratio and maximum false lock margins. The optimum bandwidth has been determined to be about three to four times the data rate. The significance of these results is that they establish an upper limit on how much the loop gain of the receiver may vary under all conditions of signal levels and frequency offsets.
Referring back to FIG. 2, note that there is approximately 20 to 1 variation in loop gain in the IQ multiplier component. This is evident from the comparison of the gain between a high gain point x and a low gain point y. This wide variation in loop gain with the total power AGC renders the total power AGC method helpless in combatting the false locks.
The foregoing discovery of the false lock problems associated with the total power AGC control led the present inventors to search for a solution whereby the loop gain can be made relatively constant at all signal levels. This led to the development of signal power sensing AGC circuitry described hereinbelow.
A functional block diagram of the inventive signal power AGC loop is illustrated in FIG. 7 schematically. As illustrated therein, the signal plus noise power in the inphase channel is estimated by a square law detector 31. The noise power only is estimated by sampling the quadrature channel with a bandpass filter 43 at a frequency where little signal energy is present but which is still within the IF bandwidth. The bandpass filter 43 may be made of a high pass filter that operates in conjunction with the IF filter of the receiver to provide necessary bandpass filtering operation. The signal pluse noise power estimate obtained by the square law detector 31 is applied to a differential amplifier 44 of a conventional design. The noise power is estimated by a square law detector 45 and the output thereof is applied to the differential amplifier 44. The differential amplifier 44 is connected to operate as a subtractive circuitry whereby the noise estimate signal from the noise estimating circuitry made of the filter 43 and square law detector 45 is subtracted from the noise plus signal power estimate signal coming from the square law detector 31 and applied to the differential amplifier 44.
In this manner the differential amplifier 44 provides an output signal which is an estimate of the signal power from which the noise power estimate is subtracted. In this manner, an output is obtained which is an estimate of signal power without the undesirable noise component present in the in-phase channel. This output is then applied to the comparator 32 where it is also filtered by the RC filters circuitry in a conventional manner and where it is compared with the AGC reference signal to provide the AGC feedback control voltage to the input IF amplifier. When the loop is acquiring and tracking, the AGC control is therefore based entirely on the signal power level.
While the ideal realization of this AGC technique would produce a truly constant signal output for any input signal level, practical realization results in some gain variation. The relationship between the input signal power and the output signal power level and the relative loop gain has been measured using an experimental Costas loop detector. The result of the experimentation is illustrated in FIG. 8 where the data signal output level is plotted in the vertical axis in a normalized form and the signal power is plotted in normalized form representing the signal to the noise ratio. The very top curve represents the locked data output level measured as a function of signal power input. The middle curve is the unlocked data plus beat note amplitude. The lower one represents the double beat note amplitude from the IQ multiplier.
The method of developing the in-lock signal with reference to FIG. 7 is by square law detecting the in-phase and quadrature channel outputs and subtracting them. The resulting difference in effect is proportional to the cosine of the tracking phase error since the AGC keeps the signal power constant. When the loop is out of lock, the signals in the in-phase and quadrature channels differ only in phase and when they are square law detected, they produce the same DC components. However, when the difference is formed, a near zero voltage results in lock comparator 37, this being because of the low threshold of the comparator and a low voltage lock signal.
The situation is different from the voltage level produced when the in-phase and quadrature channels are different only in-phase. When the loop locks the digital data is present in the in-phase channel while only noise will exist in the quadrature channel. Now when the difference is formed a substantial DC voltage results and the lock comparator produces a high output signifying the in-lock condition.
The lowpass filter made of R1 and C1 disposed between the comparator 46 and the lock comparator 37 establishes the response time of the lock detector.
Various changes and modifications may be made to the present invention, an illustrative embodiment of which is illustrated and described hereinabove, without departing from the spirit and scope thereof.
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An automatic gain control (hereinafter referred to as AGC) circuitry is used in conjunction with a Costas loop detector to provide positive gain control during the acquisition and tracking modes of the operation of a receiver. The circuitry includes circuitry for deriving a noise estimate signal from one channel of the Costas loop and circuitry for subtracting the noise estimate signal from the data and noise signal combination in the other channel of the Costas loop for providing the automatic gain control signal to prevent false locking.
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BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a method of producing a large-area membrane mask based upon an existing or to be produced multi-layered semiconductor—insulator—semiconductor carrier layer wafer (SOI substrate), in which, firstly, the semiconductor layer is structured by the forming of mask openings and, subsequently, the SOI substrate underneath the mask openings is removed from its rear side by at least one dry-etching step, so that a membrane formed by the structured semiconductor layer and held by a carrying ring is produced.
Such a dry-etching method in the SOI wafer flow process is already disclosed in International Application WO 99/49365.
In semiconductor technology, the structuring of the silicon wafer is today performed almost exclusively with the aid of the lithographic technique, in which a resist pattern is firstly produced on the wafer in a radiation-sensitive resist layer and then serves as a mask in a following process step, for example, etching. Thereafter, the resist mask is removed again. The resist pattern itself is likewise produced with the aid of a mask suitable for the respective exposure method. In conventional photolithography, chromium masks (reticles) that include a glass plate as the carrier and a thin structured chromium layer are used. Even when weakly absorbent materials such as silicon are used, masks for X-ray lithography allow only mask carrier thicknesses in the micrometer range. This is accomplished by membrane masks that have a central active region, in which they are thinned with respect to the membrane, and a supporting edge (carrying ring) in the original thickness of the silicon substrate. In the case of X-ray masks, a geometrically structured absorber layer is provided on the membrane layer.
In the case of electron and ion lithography, membrane masks in which the mask openings are not produced on the membrane layer but in it have to be used. The membrane layer, the thickness of which lies in the micrometer range, contains mask openings or holes in a way corresponding to the figures to be lithographically produced. Consequently, as in the case of all membrane masks, such aperture masks (stencil masks), as they are referred, are mechanically comparatively unstable formations.
For electron and ion projection lithography and also for newer versions of X-ray lithography, membrane masks with thicknesses in the micrometer range and with membrane areas of up to over 100 cm 2 in size have to be produced. The membrane masks produced by the method according to the invention can be used in general for lithography methods with charged particles and with photons. An example is use in the case of 13 nm lithography (soft X-rays). Similarly, use for masking with respect to neutral particles (atom lithography) and in all applications as an evaporation mask is possible. Membrane masks as a product of a method according to the present invention can also be generally used for sensors.
Based upon silicon wafers as a substrate material, two different technological process variants are pursued for producing the membrane masks. They differ in principle according to whether the process steps for the mask structuring take place before (wafer flow process) or after (membrane flow process) the production of the membrane.
In the case of what is referred to as the wafer flow process, as presented, for example, in International Application WO 99/49365, the mask structures are firstly produced on a compact silicon wafer and the production of the membrane by etching the rear side of the substrate takes place at the end of the process. Such a process variant makes it possible, on one hand, to carry out the structuring processes for the mask structures on stable wafers, which can be better controlled in terms of the process. On the other hand, in the case of such a variant, there are also very high requirements on the membrane etching process because the structured membrane side has to be protected absolutely securely from an etching attack. Boron doping of the membrane layer has been conventionally provided as the etching stop technique, although this often does not provide precisely enough defined conditions. Recently, therefore, SOI (Silicon-on-Insulator) substrates have also been used, likewise described in International Application WO 99/49365. In this case, the buried oxide layer in the SOI wafer serves as the defined etching stop and the doping of the membrane layer can be chosen as desired based upon other aspects.
The problems underlying the invention are explained below based upon FIG. 1A , which represents the result of a membrane dry-etching process according to the prior art.
Previously, the replacement of the conventional wet-chemical etching methods by dry-etching processes in the critical membrane etching step in the production process was more a wish than a reality. Even in International Application WO 99/49365, only wet-etching methods are specifically discussed. The dry-etching methods have two fundamental advantages. On one hand, it is a process that is compatible with the common methods in the semiconductor industry. On the other hand, the etching rate in dry-etching processes is independent of the crystal orientation in the silicon.
Problematical in the dry etching of silicon areas of several square centimeters in size is, in particular, the fact that the silicon etching rate is inhomogeneous over the area to be etched. FIG. 1A shows a typical inhomogeneous etching profile. Based upon a semiconductor—insulator—semiconductor carrier layer substrate, the structure of the membrane, that is, the mask openings 6 , was transferred into the uppermost semiconductor layer 1 , which serves as the future membrane layer. In a further step, the semiconductor carrier layer 3 is to be removed from the underside as far as an outer ring 8 (protected by the masking layer 4 ), so that the semiconductor layer 1 resting on the carrying ring 8 represents the structured membrane by its exposed central region, clamped by the carrying ring 8 . In general, however, there has previously been an inhomogeneous etching removal, as represented for example in FIG. 1 A. In the case of FIG. 1A , the etching rate is lower in the center of the wafer than in the edge region. In the production of large-area membrane masks, this etching inhomogeneity means a long overetching time, in particular, for the transitional membrane/wafer region. This may lead to etching through of the insulator layer and, accordingly, to destruction of the semiconductor membrane layer.
Furthermore, in the case of silicon dry-etching processes there is a problem of a strong dependence of the silicon etching rate on the silicon area offered (degree of occupancy). Added to this is the clamping and handling of thin, large-area silicon wafers during and after the dry-etching process, which cannot be carried out by the previous methods (etching cell etc.).
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method of producing large-area membrane masks by dry etching that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that is improved with regard to the problems mentioned.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a method for producing a large-area membrane mask based upon one of an existing and to be produced multi-layered semiconductor layer—insulator layer—semiconductor carrier layer wafer having a rear side, a center region, and an edge region, including the steps of structuring the semiconductor layer by forming mask openings, subsequently removing the wafer underneath the mask openings from the rear side by at least one dry-etching step to produce a membrane formed by the structured semiconductor layer and held by a carrying ring, and covering the wafer in a region of the carrying ring with a masking layer during the at least one dry etching step, thereby causing irregularity of etching conditions between the center region and the edge region of the etched portion of the wafer, and counteracting such irregularity by providing an approximately homogeneous etching removal over an entire area of the wafer to be etched by one of, for an existing wafer, providing an additional layer construction compensating for the etching irregularity to at least one of a masking region and an open area of the semiconductor carrier layer to be etched, for an existing wafer, moving a mechanical etching diaphragm in front of the semiconductor carrier layer to expose the edge region to etching attack for a shorter time than the center region, and, during a production of the wafer, providing at least two insulator etching stop layers one on top of the other and separated by an inner semiconductor carrier layer, the inner semiconductor carrier layer being thinner than the semiconductor carrier layer etched in a first partial etching step. Preferably, the wafer is an SOI substrate.
The method is based on the realization that the inhomogeneity in the silicon dry-etching processes is based on the fact that, due to different materials to be etched (silicon; oxide or resist as masking layer), different etching conditions exist in the edge region of the silicon wafer than in the center (in particular, lower consumption of etching media above the masking layer than in the center). This means a greater and quicker depletion of the reactive species in the center of the wafer and, consequently, a lower etching rate than in the edge region. The invention provides the stated alternative measures to compensate at least partially for the inhomogeneous neighboring conditions and, as a result, accomplish an approximately homogeneous etching removal. Furthermore, high etching rates and selectivities are achieved.
In accordance with another mode of the invention, the semiconductor carrier layer is a silicon carrier layer, and which further comprises applying a silicon ring, forming the additional layer construction and/or the masking layer and the additional layer construction, to the silicon carrier layer in the masking region, the silicon ring having a thickness that is sufficient to protect the silicon carrier layer in the masking region in spite of its own progressive etching removal.
Alternatively, in accordance with a further mode of the invention, it is possible for a masking pattern, reducing the degree of silicon occupancy of the semiconductor carrier layer, to be applied as an additional layer construction to the open area to be etched, so that, after a first dry-etching step, remains of the semiconductor carrier layer corresponding to the masking pattern initially remain.
In such a case, it is advantageous that, in a further etching step, the remains remaining after the first dry-etching process are removed together with the insulator stop layer by underetching. The masking pattern may be applied by depositing and subsequently structuring a masking layer or by attaching a prestructured masking, in particular, a film structured in a grid-like manner.
In accordance with an added mode of the invention, the masking pattern is applied by depositing and subsequently structuring a masking layer and/or attaching a prestructured masking.
In accordance with an additional mode of the invention, the prestructure masking is a film structured in a grid shape.
In accordance with yet another mode of the invention, a gray-scale mask is produced, and a mechanical etching diaphragm is used or an SOI substrate with at least two insulator etching stop layers is used.
In accordance with yet a further mode of the invention, a gray-scale mask is produced in the transitional masking region/open area region as an additional layer construction.
In accordance with yet an added mode of the invention, etching is performed utilizing a rotating etching diaphragm having a diaphragm opening formed larger in the center region than in the edge region.
In accordance with yet an additional mode of the invention, etching is performed utilizing a periodically opening and closing iris diaphragm.
In accordance with a concomitant mode of the invention, provides that, before the dry etching, the wafer structured on the front side is attached with the semiconductor layer on a handle wafer by wax or an adhesive film and that the wafer is separated again from the handle wafer after the membrane etching. This can be used in the case of all alternatives of the method of the invention.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method of producing large-area membrane masks by dry etching, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a diagrammatic illustration of a typical inhomogeneous etching profile according to the prior art;
FIG. 1B is a diagrammatic illustration of a typical approximately homogeneous etching profile according to the invention;
FIGS. 2A to 2 F are cross-sectional views of successive partial steps of a method according to the invention using a masking pattern;
FIGS. 3A to 3 G are cross-sectional views of successive partial steps of an alternative method according to the invention using two etching stop layers; and
FIGS. 4A to 4 D are cross-sectional views of successive partial steps of a preparation method according to the invention using a handle wafer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawings in detail and first, particularly to FIG. 1B thereof, there is shown a configuration according to the invention. By applying a silicon ring 5 of silicon to the semiconductor carrier layer, and consequently offering silicon also in the edge region (masking region) of the wafer to be etched, it is possible to compensate largely for the depletion effect described above. The virtually homogeneous etching result (remains 7 ) is shown in FIG. 1 B. The silicon ring 5 , originally having approximately the thickness of the semiconductor carrier layer 3 , was removed at the same time down to the remains shown. In addition, the size of the membrane is defined by the material-compensating silicon ring 5 , leading to matching of the etching conditions in the transitional membrane/carrying ring region. As a result, the silicon ring 5 may either directly form the additional layer construction and at the same time the masking layer 4 , or a traditional masking layer 4 , for example, polymer, dielectric, or metal, may be located under the silicon ring 5 .
FIGS. 2A to 2 F, in particular, FIG. 2A shows as a starting point 2 A an SOI substrate with a semiconductor carrier layer 3 , a semiconductor layer 1 and with a buried insulator layer 2 in between. By suitable choice of a rear side pattern (masking pattern 9 ), the degree of silicon occupancy, that is the proportion of the open silicon area within the entire silicon rear side, the semiconductor carrier layer 3 , is reduced and, as a result, the silicon etching rate is increased. At the same time, the problem of depletion of the reactive species in the center of the wafer is reduced and, consequently, the homogeneity of the etching is increased.
Partial step 2 B shows the application of a masking pattern 9 with structures of the order of magnitude of 100 micrometers. Suitable as materials for a prestructured masking are a free dielectric film, a metal foil, a polymer film, or a combination of films/foils. However, with analogous materials, a masking layer can similarly be deposited and structured for the masking pattern 9 . The masking pattern 9 effectively makes the open area to be etched match the conditions at the edge that is over the annular masking layer 4 . Furthermore, a resist layer 10 for the mask openings 6 is applied and structured.
In the next partial step 2 C, the (trench) etching of the mask openings 6 takes place in the semiconductor layer 1 and, subsequently, partial step 2 D, the removal of the resist layer 10 and the depositing of a protective layer 11 .
The masking and silicon remains 12 remaining after the membrane etching, partial step 2 E, are underetched and removed in subsequent etching steps during removal of the etching stop layer 2 . The semiconductor layer 1 , supported by the carrying ring 8 , then forms the structured membrane. After removal of the protective layer 11 , the end state shown in FIG. 2F results.
With precise knowledge of the process parameters
homogeneity etching rates selectivity
of the dry-etching process, it is possible to expose into a photoresist in the transitional membrane/carrying ring region a thickness profile that corresponds to an inverse etching profile (gray-scale mask). As a result, it is possible to compensate exactly for the irregularity of the dry-etching process.
By rotation of a mechanical etching diaphragm with a specific pattern of openings in front of the semiconductor carrier layer 3 , it is possible to achieve the effect in the etching system that the etching times are adapted to the respective etching rates such that a homogeneous etching removal takes place over the entire area. The edge region of the silicon wafer is exposed to the etching attack of the reactive species for a somewhat shorter time than the center. By adapting the diaphragm rotation speed and the degree of diaphragm opening, a very homogeneous etching removal can be achieved.
A homogeneous etching removal can likewise be achieved by periodically opening and closing a mechanical iris diaphragm, which is provided in front of the semiconductor carrier layer 3 in the etching system.
FIGS. 3A to 3 G show a simplified process flow for the production of the mask, starting with silicon wafers with two buried etching stop layers. These can be produced in a conventional way, in particular, by implantation of oxygen. The SOI substrate with a lower etching stop layer 2 and an upper etching stop layer 13 , which are separated by an inner semiconductor carrier layer 14 , serves as a mask blank, cf. FIG. 3 A. Such a construction makes it possible to compensate for etching inhomogeneities that occur during the removal of the membrane carrier layers because, although any inhomogeneities after the first partial dry-etching step, FIG. 3D , have been transferred into the upper, relatively thick etching stop layer 13 , an inhomogeneity in the stop layer 13 does not present any problem because the stop layer 13 is removed by a highly selective wet-etching process, cf., FIGS. 3E and 3F .
The etching stop layers 2 , 13 may be dielectric, metal layers or a combination of these.
To be able to use dry-etching processes for the production of membrane masks, a suitable preparation technique is needed, ensuring safe handling of the silicon wafers to be etched in the etching system during the etching process and nondestructive detachment of the thinned membrane wafer. By adhesively attaching the membrane layer, that is the front side of the SOI substrate, cf., FIG. 4A , onto a handle wafer with wax 16 or an adhesive film, the fragile stencil structures are mechanically protected and safe handling is ensured.
After the membrane etching, the membrane wafer 1 , 2 , 8 can be separated from the handle wafer 15 by dissolving the wax 16 or the adhesive film without leaving any residual remains. Such a preservational method ensures a high yield in such a critical process step.
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Based upon an existing or to be produced multi-layered semiconductor-insulator-semiconductor carrier layer wafer (SOI substrate), irregularity of the etching conditions between the center and the edge region occurring during dry etching can be counteracted by a number of alternative steps, in particular, an additional layer construction compensating for the etching irregularity so that in any event an approximately homogeneous etching removal takes place over the entire area of the wafer to be etched.
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FIELD OF THE INVENTION
This invention relates to looms or weaving machines and, more particularly, to improvements in varying warp tension for weaving stylized designs, such as leno patterns.
BACKGROUND OF THE INVENTION
The use of means for varying warp tension for fancy weaving of stylized designs, such as leno patterns, is not new. Among such means are easer-bar, slackener bars, jumper motions, etc. Those means have been operated, however, by negative type dobbies, i.e., they positively pulled the harness frames or heddles upward but the frames were pulled downward by springs. Similarly, the motion of the dobby-controlled easer-bar was negative, i.e., moved positively in one direction by the dobby, but moved in the opposite direction by springs.
Such known means for varying warp tension is satisfactory for old type fly-shuttle looms, but unsatisfactory for rapier type weaving machines which operate much faster. Full speed capabilities of rapier type looms cannot be obtained with negative motion easer-bars, even when such looms are equipped with positive motion dobbies which positively move the harness frames both upward and downward.
Moreover, some known types of easer-bars are in the form of three rollers, two fixed in spaced relation and the third movable between the two fixed rollers. This complicates the construction and renders it more expensive.
Examples of means for controlling warp tensions are disclosed in the following U.S. patents:
Bohan U.S. Pat. No. 2,246,658, June 14, 1941; willis et al. U.S. Pat. No. 2,551,920, May 8, 1951; Kulczycki et al. U.S. Pat. No. 2,589,498, Mar. 18, 1951; Pfarrwaller U.S. Pat. No. 3,125,128, Mar. 17, 1964.
Bohan is exemplary of a whip roll which is automatically raised and lowered to compensate for variations in warp tension, i.e., to maintain constant warp tension in a shedding cycle.
Willis discloses a whip roll which is moved, on movement of the shipper handle of the loom to "off" position, to relax the tension in the warp yarns to prevent "set marks".
Kulczycki et al discloses another type device for performing the same function as the movable whip roll of Bohan, i.e., maintaining constant warp tension during a shedding cycle.
Pfarrwaller discloses still another type of device for performing the same function as the devices disclosed in Willis and Kulczycki.
BRIEF SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide simple and inexpensive positive-motion easer-bar means controlled by a positive-motion dobby to control top beam warp tension in a high speed loom without limiting or restricting loom speed.
It is another object of this invention to provide such an easer-bar on a rapier type weaving machine which maintains positive control of the easer-bar motion and does not reduce or restrict machine speed.
These objects are accomplished by an easer-bar which overlies the top beam warp threads at the juncture of their vertical and their horizontal run and is mounted for rocking movement toward and away from the warp threads. Mechanical means positively connects the easer-bar to a positive-motion dobby to rock the easer-bar to decrease warp tension at predetermined intervals for weaving fancy leno type fabrics in accordance with the pattern of the dobby.
Other objects and advantages will become apparent from the following description and accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWING
The drawing is a schematic, partially exploded, perspective view of an easer-bar and driving means therefor embodying this invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawing, there is disclosed portions of a Dornier rapier type weaving machine having a frame and a top and a bottom warp beam (not shown) from which top beam warp threads 10 are drawn downwardly in a generally vertical and thence in a generally horizontal run under the arch member 14 of the frame through the usual shedding harnesses or heddles (not shown). Overlying, parallel to, and extending from side-to-side of the juncture of the vertical and horizontal run of the top beam warp threads 10 is an easer-bar in the form of a roller of light weight material, e.g., aluminum. Stub shafts 18 at each end of the roller 16 are rotatably mounted, by anti-friction bearings 20, to the ends of crank arms 22 fixedly attached to an oscillatory shaft 24 disposed parallel to the roller 16 beneath the horizontal run of the warp threads 10 and having its ends journalled in the side frame members 26 of the machine. It will be seen that the roller 16 can be rocked toward the whip roll 12 to increase the tension on warp threads 10 or rocked away from the whip roll to decrease or completely relieve the tension therein caused by engagement of the roller therewith.
Pivotally connected to each crank arm 22 and to a corresponding crank arm 28 attached to an oscillatory shaft 30 extending from side-to-side of the loom parallel to the shaft 24 beneath the arch member 14 of the frame is a connecting rod 32. The ends of the shaft 30 are journalled in brackets 34 fixed to and depending from the arch member 14. Attached to the shaft 30 adjacent the crank arms 28 are generally horizontal crank arms 36 each having a connecting rod 38 connected thereto for pivotal movement about an axis parallel to the shaft 30 and depending from such arm 36 below and at one side of the horizontal run of the warp threads 10. The lower end of each rod 38 is connected for pivotal movement about a horizontal axis to one generally horizontal arm of a corresponding double arm crank 40 mounted on a corresponding rod 42 for oscillation about a horizontal axis extending in a plane normal to the axis of the shaft 30. The crank mounting rods 42 are fastened by bracket structures 44 to side bed members 46 of the loom frame. The other arms of the double arm cranks 40 extend generally vartically, with one extending upwardly and the other downwardly. These arms of the cranks 40 are connected by a connecting rod 48 so that oscillation of one crank 40 causes the connecting rods 38 to move up or down in unison and thereby rock the easer-bar roller 16.
The generally vertical arm of one of the cranks 40 has a connecting rod 50 pivotally connected to the generally-horizontally positively-reciprocable member 52 of a dobby 54. Reciprocation of the member 52 is controlled by the predetermined pattern of the dobby 54 to rock the easer-bar roller 16 to decrease or relieve the tension in the warp threads 10 at predetermined intervals for weaving leno type stylized designs.
Although the preferred embodiment described hereinabove contemplates that the leno warp ends will be provided by a singular top beam, it is understood that the leno warp ends could be provided by a plurality of top beams or one or more bottom beams. Regardless of the location of the beam or beams providing the leno warp ends, leno warp ends will be contacted and tensioned by the easer bar of the present invention.
It thus will be seen that the objects and advantages of this invention have been fully and effectively achieved. It will be realized, however, that the foregoing specific embodiment has been disclosed only for the purpose of illustrating the principles of this invention and is susceptible of modification without departing from such principles. Accordingly, the invention includes all embodiments encompassed within the spirit and scope of the following claims.
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An easer bar for controlling the tension of the warp threads in a loom controlled by a positive action dobby for weaving leno type fabrics is directly controlled by and connected to the dobby.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system for analysis of molten metal. More particularly, this invention relates to a system capable of removing a solid sample from a source of molten metal; dissolving the sample; and then analyzing the dissolved sample.
2. Description of the Prior Art
In the production of metal alloys such as, for example, an aluminum base alloy, it is desirable to determine the alloy content while the alloy is still in molten form. This, in turn, permits the addition of further alloying materials, or more base metal if the alloying metals are more concentrated than desired, while the alloy mixture is still molten.
Various methods of analyzing such molten metals are possible. In its simplest form, such analysis could comprise taking a sample from the melt and sending it out for spectral analysis. This, of course, would involve an unacceptable time lag. On the other hand, however, direct spectral analysis of the molten metal would create problems if sensitive spectrometer equipment was located in immediate proximity to a furnace containing molten metal.
Various alternative methods of analysis have been previously proposed. For example, Bojic U.S. Pat. No. 3,659,944 describes a system wherein a stream of molten metal is drawn into a spark chamber where the molten metal comes in contact with one electrode. The light or radiation generated by a spark between the molten metal and a second electrode is directed into a spectrometer to provide direct analysis of the molten metal. However, such a method involves the transport of molten metal from a furnace to the spark chamber and further results in the need to transmit the emitted spectra to the spectrometer if the spark chamber is located near the molten metal.
Virgolet U.S. Pat. No. 3,669,546 illustrates a system for analysis of molten metal wherein one electrode is placed directly into the molten metal bath and an electric arc is generated between the surface of the bath and another electrode placed adjacent the surface. The light emitted from this electric arc is then transmitted by a series of mirrors to a spectrograph where the light is analyzed to determine the content of the molten metal. Similar systems are disclosed in Bojic et al U.S. Pat. Nos. 3,645,628 and 3,672,774 wherein light is produced by generating sparks between an electrode and the surface of a crucible filled with molten metal and in contact with a second electrode. The light thus produced is directed to a spectrometer for analysis. Such systems, however, require the transmission of the emitted light to a spectral analysis apparatus spaced some distance from the furnace and thus some distance from the point of generation of the light.
British Patent Specification No. 1,116,052 shows a mechanism for analyzing molten material by passing a gas under pressure into the molten metal to produce metal particles which are then transported out of the bath to a spectrograph for analysis by feeding the particles or dust into a plasma jet. Production of metal particles from molten metal is also shown by Maringer U.S. Pat. No. 4,154,284 who teaches the production of metal particles such as metal flake by dipping a portion of a rotating wheel into a pool of molten metal. The wheel is provided with sawtooth-like serrations which pick up the molten metal as the wheel passes through the molten metal pool. As the wheel emerges from the molten metal, centrifugal force and/or contact with gases cause the now solidified metal to break off as flakes from the rotating wheel. The serrated surface of the wheel may also be cleared of any adhering metal from the molten metal pool by contacting the serrations with a brush.
Kenney International Application PCT/US84/01148, however, points out that problems such as interruption of particle flow due to clogging can occur in attempting to transport such metal powder. Instead, Kenney proposes a system for analysis of molten metal wherein an atomization die is used in connection with pressurized inert gas to form an aerosol or dispersion of solidified metal particles in the gas. This aerosol or dispersion is then delivered to an inductively coupled plasma torch which causes the particles to emit spectra characteristics of their constituent elements which may then be analyzed with a spectrometer.
SUMMARY OF THE INVENTION
It would, however, be preferable to provide a system for on-line analysis of the contents of a molten metal bath at a position remote from the bath which was not dependent on the transporting of either emitted spectra or powders and/or aerosols to the remote spectral analysis position.
It is therefore an objective of this invention to provide an improved system for the analysis of a molten metal source.
It is a further objective of this invention to provide an improved system for the analysis of a molten metal source wherein a sample of solid metal particles from the molten metal source is removed from the source, dissolved in a solvent, and then transported to a spectrometer for analysis.
These and other objectives of the invention will be apparent from the following description and accompanying drawings.
In accordance with the invention, a system is provided for analyzing molten metal which comprises removing a sample of metal from a source of molten metal; dissolving the sample in a solvent; and analyzing the dissolved sample to determine the contents of the molten metal. In a preferred embodiment, the sample is removed from the molten metal as solid particles in a sampling zone, conveyed in a fluid to a dissolution zone where a known quantity is dissolved for subsequent spectral analysis, and the resulting solution is then passed to a spectral analysis zone.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow sheet illustrating the system of the invention.
FIG. 2 is a partial cross-sectional view of a sampling zone that includes a sampling wheel.
FIG. 3 is a schematic representation of a sample processing chamber, which chamber is a dissolution zone and compartment.
FIG. 4 is a diagramatic view of the system of the invention.
DETAILED DESCRIPTION OF THE INVENTION
As depicted in the flow sheet of FIG. 1, the system of the invention provides for the collection of solid metal particles from a source of molten metal, the fluid transmission of these particles to a dissolution zone, the dissolving of the solid metal particles in a solvent, passing the solution to a spectral analysis zone, vaporization of the solution, and analysis of the emitted spectra to determine the contents of the molten metal source.
In a preferred embodiment, as illustrated in FIG. 2, solid metal particles 12 are collected from the molten metal source 10 by partially immersing a spinning wheel 20 into the source. Wheel 20 may, for example, comprise an 11-inch diameter copper wheel, preferably with serrations or sawtooth edges 22. Wheel 20 is lowered into molten metal source 10 to a depth of, preferably, no greater than 0.5 millimeter. At the same time, wheel 20 is rotated at a speed of from about 200 rpm. As wheel 20 rotates, molten metal solidifies in the serrations 22, contracts, and is ejected from wheel 20 by centrifugal forces to be collected in hood means 40, as will be described below. A brush 34 located in the manner shown in FIG. 2 or an air jet may be used to assist in removal of metal particles from serrations 22 if desired.
Preferably, serrations 22 comprise sawtooth-shaped edges each having a leading edge of about 0.078 inch and a length of about 0.22 inch with the hypotenuse of the sawtooth forming a 20° angle with the length to thereby provide about 150 to 160 serrations on an 11-inch diameter wheel. With these dimensions, it is possible to produce metal flakes having a range of particle sizes from approximately 0.12 to 0.4 cm in length, 0.04 to 0.15 cm in width, and 0.016 to 0.020 cm thick with an approximate weight of between 0.00026 to 0.004 grams per flake.
A fairly reproducible or known amount of metal particle or flake sample can thus be collected by lowering wheel 20 into molten metal source 10 for a measured increment of time and at a known speed of rotation and then raising wheel 20 out of the pool of molten metal. Alternatively, the flakes or particles can be weighed in a weight station with an increment of sample transported to the dissolution zone only when a certain weight of sample is reached.
Turning now to FIG. 3, solid metal flakes or particles 12, as they dislodge from serrations 22 in wheel 20, are collected by hood means 40 which is positioned in the path of travel of the particles. Hood means 40 is connected, via tube or pipe 42 (FIG. 2), to a tube or pipe 62 that delivers the particles to a processing chamber 70. A vacuum is produced in 70 and in a compartment 80 of 70 by means of a blower means (not shown) attached to an exit port 90 (FIG. 3) of chamber 70. This vacuum causes metal particles to be transported from hood 40 through pipes 42 and 62 into the sample processing chamber. Tube 62 can be of substantial length to allow processing of flakes 12 at a location remote from that of their origin.
Sample processing chamber 70 includes a first compartment 80 having an inlet opening 82 connected to tube 62, which opening includes an inlet tube 84 that protrudes into compartment 80. Tube 84 terminates in an opening 86 which faces downwardly in compartment 80. The metal particles entering compartment 80 thus lose momentum and fall through compartment 80 into a dissolution chamber 100 via port 96 located below 80.
Sample processing chamber 70 includes a second, dissolution chamber 100 provided with a solvent inlet 108 through which a measured amount of solvent is admitted into chamber 100 to dissolve the metal particles entering through port 96. The solvent is dispensed in chamber 100 in such a way as to provide a washdown of the sides of dissolution vessel 100.
A lower portion of dissolution chamber 100 has a sample solution outlet 104 and a drain 106. Drain 106 contains a porous frit 110 that does not react with the solvent. Frit 110 prevents solid materials from leaving compartment 100. A vent tube 102 is shown connected to an upper side portion of compartment 100 to vent out gases that may be produced as the solid particles are dissolved. This venting is promoted by utilizing a flow of air to and through a nipple 92 during dissolution, nipple 92 being connected to an upper portion of compartment 80.
The solvent used to dissolve the metal particles preferably is a mineral acid such as a 50% HCl solution. Any other solvent capable of rapidly dissolving the metal sample may, however, be used. The term "rapidly" means the use of a solvent capable of dissolving the sample in about 30 seconds or less. For example, when a sample of aluminum flakes weighing approximately 0.1 gram is used, 10 milliliters of 50% HCl will dissolve the sample in about 10 seconds.
After the solid metal sample is dissolved, the sample solution is pumped out of dissolution compartment 100 through outlet 104 and into spectral analysis apparatus 140 (FIG. 4) in a manner described below. It should, however, be noted here that as soon as the dissolved sample leaves dissolution compartment 100 another sample may begin to be collected by again dipping wheel 20 into the molten metal to permit the collection and transport to processing chamber 70 of a new sample of solidified metal for eventual analysis. In this manner, an on-line or semi-continuous measurement of the contents of a molten metal source may be maintained.
Spectral analysis apparatus 140 may comprise any conventional spectrometer capable of vaporizing a liquid sample. Such spectral analysis equipment, conventionally known as an Inductively Coupled Emission Spectrometer, is commercially available.
Referring now to FIG. 4, the components of which are only schematically represented, a tube 116 leads from outlet 104 (FIG. 3) to a first valve 120. Valve 120 is a three-way valve which has a second inlet 132 connecting valve 120 with a standard solution which may be used to calibrate spectral analysis apparatus 140. A tube 126 connects the outlet of valve 120 with one inlet of a second three-way valve 122. A second inlet of valve 122 is connected via tube 128 to the outlet of a third three-way valve 124. Valve 124 has an inlet 134 connected to a source of wash solution which may be pumped into spectral analysis apparatus 140 to clean the apparatus between runs. A second inlet 136 to valve 124 connects to an optional second standardized solution used to calibrate apparatus 140. Valves 120, 122, and 124 preferably are solenoid-operated valves which may be controlled by a central control unit (not shown) and which may also be used to control the remainder of the sampling apparatus, including wheel 20 (FIG. 2) and the input of solvent into dissolution chamber 100 (FIG. 3).
Connected to the outlet of valve 122 via tube 138 is a pump 130 which will pump into spectral analysis apparatus 140 whichever solution is set to pass through valves 120, 122, and 124 depending upon the settings of the valves.
The sample solution then, passes through outlet 104 (FIG. 3) and tube 116 from dissolution, chamber 100 (FIG. 3) into valve 120 and then via tube 126 into valve 122 from whence it passes through pump 130 into spectral analysis apparatus 140. The sample solution then is vaporized in spectral analysis apparatus 140 and the contents of the molten metal source are determined by comparing the emission spectra given off by a known amount of the sample to the emission spectra given off by vaporizing a known amount of a metal alloy of known alloy content.
In summary, the system of the invention provides for the analysis of a molten metal source by removing a solid sample from the molten metal source, transporting the sample to a dissolution zone in a fluidized medium, and then passing to a spectral analysis apparatus a solution containing the sample. In this manner known amounts of sample may be analyzed to determine the amount of alloying materials in the molten metal in a rapid yet accurate manner. The various zones can be controlled by a central control unit, such as a process control computer, and the zones may sequentially process different samples to thereby accelerate the overall monitoring of the content of the molten metal source.
While the invention has been described in terms of preferred embodiments, the claims appended hereto are intended to encompass all embodiments which fall within the spirit of the invention.
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A system is disclosed for analyzing molten metal which comprises removing a sample of metal from a source of molten metal; dissolving the sample in a solvent; and analyzing the dissolved sample to determine the contents of the molten metal. In a preferred embodiment, the sample is removed from the molten metal as solid particles in a sampling zone, conveyed in a fluid to a dissolution zone where a known quantity is dissolved for subsequent spectral analysis, and the resulting solution is then passed to a spectral analysis zone.
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This is a continuation application of PCT/AT98/00048, filed Mar. 3, 1998.
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing an RF/HF induced, low-energy plasma, in particular noble gas plasma, and a device for producing an RF/HF induced, low-energy plasma, in particular noble gas plasma, comprising a generator and a supply element for the plasma gas.
Methods and devices for producing a plasma, in particular noble gas plasma, are known in various embodiments, wherein such a plasma can be used for example as radiation source, in particular in emission spectrometry. By providing for a sample in the plasma, further possible applications of such a plasma are for example in the field of investigations relating to atomic emission, chemiluminescence, ion mobility, and as ion source for mass spectrometry. Without providing for a sample such a plasma can for example be used as a source for slow, thermalized electrons. In the field of ionization techniques for mass spectrometry such an electric discharge can be used instead of the commonly used corona discharge to ionize a component: of the gas, whereby this component in turn ionizes the sample molecule. In the context of a photoionization detector such a plasma can be used as a point-source for VUV radiation. In the context of ozone production a microplasma can be employed when in certain applications the total gas flow during ozone production has to be very low, for example when the ozone is to be introduced into the vacuum chamber of an analytical instrument. Furthermore such a plasma can for example generally be used for the production of redox-reagents to be introduced in small amounts into gaseous or liquid systems. Further possible applications of such a plasma comprise the use as VUV light source for the treatment of surfaces, in particular at atmospheric pressure.
For the production of plasmas various methods are known. Besides the possibility to form plasmas by means of an electric arc, preferably methods and devices are used, in which the energy necessary for plasma formation and maintenance is coupled to the gas by electromagnetic waves. Such a method and apparatus for the production of an HF-induced noble gas plasma can be found for example in DE-OS 36 38 880, wherein the energy should be coupled into the plasma capacitively. Relating to a microwave-induced noble gas plasma EP-A 0 184 912 can serve as an example, wherein in that known embodiment the microwave-induced plasma is subsequently to be employed for photoionization detection.
Problematic in such known methods and devices is on the one hand the coupling of the electromagnetic energy into the plasma gas, wherein in the known methods the employed power is in the range of approximately hundred watts. Therefore the power to be coupled is very high, wherein in addition to that of course adequate heat dissipation has to be provided in immediate vicinity of the produced plasma, to avoid damage to parts of the apparatus. For this purpose for example tubes made of an electrically non-conducting, high-temperature resistant material are used to separate the gas or plasma from the remaining parts of the apparatus, wherein it is immediately apparent that by providing such enclosing elements for the plasma, there is in addition increased need for adequate cooling devices, which renders the production of a plasma of low spatial spread, and preferably of a plasma which can be termed essentially and idealized as point-like, more difficult or even impossible. Such a device is known for example from U.S. Pat. No. 4,654,504.
In addition to that a plasma panel has been known from DE-A 26 46 785, wherein a discharge path is confined by layers of insulating material, and for the production of the plasma there are provided ring electrodes, which are supplied by direct current.
Furthermore devices are known, which use a plasma for either etching or coating of surfaces, for which EP-A 303 508 or JP-A 8274069 give examples. A plasma machining apparatus can for example be found in JP-A 8273894.
In addition to the possible applications for a low-power plasma, as discussed in detail above, plasma-arc torches can be found for example in DE-A 38 14 330 or DE-OS 25 25 939, which due to their high-energetic plasmas are not directly comparable with applications in the low-energy range.
SUMMARY OF THE INVENTION
Starting from the state of the art mentioned at the outset, the present invention aims at providing a method and device for the production of a low-energy plasma, by which, from a process-engineering point of view, a simple and stable way of producing a low-energy plasma is provided. With this it is in particular aimed at providing a plasma of low spatial spread with simultaneously simplified heat dissipation.
To solve these objects, the process of the subject invention for producing a RF/HF induced low-energy plasma, in particular noble gas plasma, is essentially wherein the energy is supplied through two parallel, interspaced, in particular ring- or disk-shaped electrodes, each having at least one through-opening, that said plasma is confined by at least one isolator, positioned between said electrodes, having at least one particularly circular through-opening assigned to the through-opening of said electrode, and that the pressure of the plasma gas is selected to be at least 0.01 bars, preferably between 0.1 and 5 bars. By confining said plasma, according to the present invention, with at least one isolator, which is positioned between parallel interspaced, in particular ring- or disk-shaped electrodes, the definition of the desired dimensions of the plasma, which can be selected according to the requirements, is successfully achieved. Furthermore it is possible to achieve through said isolator, in the particularly circular through-opening of which said plasma is produced and maintained, in a simple way and without the provision of additional confining elements, such as tubes in known embodiments, safe confinement of said plasma and simultaneously securing heat dissipation from the immediate vicinity of said plasma. By the particularly ring- or disk-shaped electrodes, which are positioned at both sides of said isolator and the through-openings of which are aligned with respect to each other, the supply of the energy necessary for the ignition and maintenance of said plasma is successfully achieved in a very small volume, so that overall a simple method for the production of such a low-power plasma, in particular noble gas plasma, can be provided at low power uptake and low gas consumption.
In accordance with a preferred embodiment it is proposed that said plasma is produced at atmospheric pressure, so that a further simplification in the implementation of the method for producing a low-energy plasma at low gas consumption can be achieved.
In accordance with a further preferred embodiment it is proposed to select the power of said plasma below 30 preferably below 10 W, so that with simple means a safe and sufficient heat dissipation can be achieved without the provision of costly cooling devices, wherein in the case of an array of plasma discharges said power can be achieved for each single discharge.
Within the scope of the method of the present invention it is furthermore proposed to preferably select the operating frequency higher than 5 kHz, preferably in the range of 50 kHz to 5 GHz, more preferably higher than 10 MHz, wherein the upper limit is essentially given by the requirement that the electromagnetic energy has to be produced by discrete components and transmitted along leads. Particularly preferable are for example the frequency ranges from 25 MHz to 45 MHz, as well as beyond 1000 MHz, in particular at approximately 2450 MHz, where simple and economic electronic components are available.
According to another preferred embodiment of the method of the present invention it is proposed, that the plasma gas is selected from helium or argon, wherein in particular helium is preferred as plasma gas due to its low atomic mass, as it causes almost no erosion at the electrodes. Moreover helium provides the best excitation conditions for halogens and other non-metals, whereas argon can be used mostly in technical applications.
In addition to the use of plasma gas for the formation of the plasma it may be provided for various applications that an additive gas is admixed to said plasma gas at an amount of at most 35 vol.-%, preferably less than 25 vol.-%, wherein said additive gas is selected from CO 2 , air, hydrogen and oxygen, as being in accordance with another preferred embodiment. At this in particular hydrogen can be added, at reduced pressure, in a relatively high proportion, wherein hydrogen is particularly important for photoionization. As additive gas oxygen is used in particular for the production of ozone or in a photoionization detector for the production of oxygen atomic emission radiation, or as dopand gas in gas chromatography to prevent the deposition of soot during the fragmentation of organic compounds.
To solve the above mentioned objects, furthermore a device for producing a RF/HF induced low-energy plasma, in particular noble gas plasma, comprising a generator and a supply element for the plasma gas, is essentially wherein said generator is coupled to two in particular ring- or disk-shaped parallel, interspaced electrodes, each having at least one through-opening, that at least one isolator is positioned between said electrodes, said isolator having at least one particularly circular through-opening assigned to said through-openings of said electrodes, designed to confine said plasma formed by a plasma gas at a pressure of at least 0.01 bars, preferably between 0.1 and 5 bars, and that said inside diameter of said through-opening of said electrodes is at least double, especially approximately four to eight times that of said inside diameter of said through-opening of said isolator for confining said plasma. In that way an extremely compact embodiment of a device for producing a low-energy plasma, the dimensions of which can be easily selected according to the requirements, is successfully achieved, while it is at the same time possible to use matched elements of a simple geometry. By selecting the inside diameter of said through-opening of said electrodes to be at least double, but especially approximately four to eight times that of the inside diameter of said through-opening of said isolator confining the plasma it is possible to achieve by compact design and reliable supply of the energy necessary for the ignition and maintenance of said plasma, protection of the electrode material from said plasma, without the provision of additional confining elements for said plasma.
According to a preferred embodiment the construction is such that the electrodes each have an essentially concentric through-opening, in particular in the shape of a cylinder or a truncated cone, which, in the case of compact implementation allow the formation of a strictly defined, spatially stable discharge region.
To reduce sputtering effects at the electrodes, while providing sufficient internal electrode surface, and to limit current density while increasing the capacitance of the electrode glow, the through-openings of said electrodes are provided with rounded edges.
As already mentioned several times above, the present invention aims at the formation of a plasma of low spatial spread, and preferably of a plasma which can be termed idealized as point-like, with a strictly defined, spatially stable discharge region, wherein in this context it is preferably proposed that the internal diameter of the through-opening in the isolator confining the plasma is less than 1 mm, preferably at least 0.01 mm, and more preferably about 0.05 to 0.3 mm, wherein the thickness of the electrodes in this case is in the range of 0.1 to 1.5 mm.
In accordance with another preferred embodiment it is provided viewed with respect to the direction of gas flow, another isolator with a through-opening, which is essentially equivalent to said through-opening of said isolator positioned between said electrodes and confining said plasma, is positioned upstream of said first electrode. By positioning, viewed with respect to the direction of gas flow, another isolator with a correspondingly narrow through-opening upstream of the first electrode, a shielding action with respect to the approaching plasma gas is achieved, so that any impairment of the gas to be fed to the plasma, before the defined gap of actual plasma production between said electrodes, with potentially resulting unwanted side-effects, is avoided. Furthermore it is avoided that elements of the device according to the invention, positioned in such a way upstream of said electrodes and isolator, are subject to erosion or any other influence which could result in a change of the actual composition of the plasma gas. The isolator positioned upstream of said plasma could, if this side is at ground potential, be made of metal, for example Pt/Ir. To reduce the number of components it is proposed in another preferred embodiment that the first electrode, viewed with respect to the direction of gas flow, and the isolator positioned upstream of it are combined into one single component and that the through-opening corresponding to the through-opening confining the plasma is followed by a preferably conically expanding opening.
To protect operative equipment which is positioned downstream of the system of said two electrodes and said interposed isolator it is proposed, in particular when said system is followed by an optical analysis device, to position an additional isolator downstream of the second electrode, viewed with respect to the direction of gas flow, the through-opening of said isolator being slightly smaller than the through-opening of the adjacent electrode, which constitutes another preferred embodiment of the device according to the invention. By selecting the through-opening of this additional downstream isolator slightly smaller than the through-opening of the adjacent electrode, protection of the electrode surface is improved and the glow discharge on the electrode is spatially confined, which stabilizes the energy uptake of the entire plasma as well as the analytical zone inside the through-opening of the middle isolator. By selecting the geometry and dimensions of said downstream isolator it is possible to adapt to the requirements of subsequent devices, as it may be essential for example when using said plasma in conjunction with detectors respecting the solid angle of the emitted radiation as well as the field of view of downstream optics, wherein said downstream isolator should have a through-opening as large as possible, to take full advantage of the large solid angle of radiation emitted by the plasma.
For an accordingly simple embodiment and exact spatial confinement of the produced plasma it is proposed that the isolator confining the plasma be disk-shaped, and that its central region, showing said through-opening, is of diminished thickness compared to the peripheral regions. The greater thickness of the isolators peripheral region provides reliable protection against electrical arcing in the unit for producing a plasma, formed essentially by said electrodes and said interposed isolator, wherein the moderate thickness in the central region of the isolator enables, by selecting an appropriate geometry, the formation of an essentially point-like plasma of accordingly low power at atmospheric pressure. In this context it is furthermore preferably proposed that the decrease of thickness of the central region of said isolator in its cross-sectional view follows an arc-shaped, in particular circular arc-shaped, parabolic or cone-shaped contour, wherein through such arched bounds of the tapered or decreased, central region an eventual erosion of the isolator and electrodes can be reduced and simultaneously a defined geometry of the glow discharges upstream and downstream of said plasma can be obtained. The arched taper of the central region of the isolator improves in particular the flow profile of the gas and moreover such a structure of the isolator increases the exposure of said electrodes to the UV radiation of the plasma.
The geometry proposed according to the invention for said electrodes and isolators enables the use of the device according to the invention in various applications. For example in applications without analytical samples in the plasma, which do riot require a comparatively low dead volume, especially the upstream electrode can be essentially disk-shaped, wherein an arbitrary opening for the supply of plasma gas must be provided, which in a modified geometry of the isolators can also be positioned laterally or eventually formed by pores.
When using the device according to the invention as plasma reactor, for example for ion mobility spectrometry or ozone production, the narrow spatial confinement of the plasma discharge, which idealized can be regarded as point-like, enables a steep temperature gradient, which is particularly important at the exit from the plasma orifice or the downstream isolator, and hence the formation of thermodynamically stabile reaction products by quenching. On the other hand, when using the device to produce a microplasma according to the present invention for example for the production of ozone or hydrogen atoms, an exit-nozzle or downstream isolator, which can be a narrow isolator-nozzle or a metal orifice positioned downstream of the second isolator, can be employed, wherein, however, for the extraction of ions an electrical isolator is advantageous.
When using the device according to the invention in the field of mass spectrometry it is possible, by employing a small orifice of the last downstream isolator in combination with an accordingly high gas flow, to achieve a steep pressure gradient in the transition zone between plasma and vacuum, wherein in this case the orifice of the exit nozzle formed by the isolator is typically smaller than the through-opening of the isolator provided upstream of the electrodes. Overall the narrow spatial confinement of the plasma and the through-opening of the downstream isolator, provided by the present invention, enable at the same time the use of low gas flows, a high pressure in the plasma and precise spatial confinement. Such low gas flows consequently result in relatively low specifications on vacuum pumps, whereby, to further optimize the supply of energy in such an embodiment, the electrode closer to the vacuum region is preferably held at or near ground potential, whereas RF-power is supplied at the other electrode. To further increase the pressure inside the plasma the supply of an additive or auxiliary gas may be provided, for example in the region between the isolator positioned between the electrodes and the downstream isolator, which defines the exit-nozzle. For special applications it is also possible to introduce the sample to be analyzed or some reagent gas in such an essentially lateral region downstream of the actual plasma.
Moreover the arrangement of electrodes and isolators according the subject invention provides, that the electrodes, or preferably their cylindrical inner surface, are illuminated as directly as possible, which results in a stabilization of the discharge by the release of photoelectrons from the metal surface.
To be able to supply the energy required for ignition and maintenance of the plasma using compact electrodes, and to obtain sufficient robustness of said electrodes it is proposed in the present invention, that the material of the electrodes is selected from gold, platinum, tantalum, niobium, iridium, aluminum, platinum/iridium alloys, gold plated metal or base metals galvanically coated with noble metals. To obtain the required electrical isolation properties and sufficient thermal conductivity of the elements confining the plasma, while maintaining possibility of precise machining, it is further proposed that said isolator confining the plasma is formed by disks of aluminum-oxide ceramics, quartz, sapphire, ruby, diamond, or electrically poorly conducting or non-conducting oxide-, nitride- or carbide-ceramics, according to another preferred embodiment of the present invention.
To facilitate assembly of the device according to the invention, wherein the central section for producing plasma, consisting of electrodes and isolators, can for example be pre-assembled, it is further preferably proposed that said electrodes and isolators are either pressed together mechanically, for example by spring action, or are bonded together by known techniques of metal-ceramic bonding, in particular by soldering in vacuum or hydrogen atmosphere.
For a particularly simple mounting of the plasma production unit it is further preferably proposed that said electrodes and said isolator or isolators are held in fixtures and are mounted in a gas-tight manner. Due to the fact that in particular the spatial dimensions of the plasma are extremely small, it is further preferably proposed that the fixtures are equipped with centering mounts for said electrodes and/or isolators, in order to accomplish uniform supply of the energy required for ignition and maintenance of the plasma.
According to a further preferred embodiment it is provided that said fixtures have outlets or purging holes, in particular for supplying an additive gas, whereby besides the supply of additive gases it is in particular possible to exhaust reaction products, which may appear in the plasma producing unit for example when the plasma is used in the context of analysis- or detector equipment.
In order to achieve appropriate sealing between the single elements at high temperature it is further preferably proposed that said fixtures are coated, for example gold plated, at least in the section of the sealing surfaces facing said electrodes and/or isolators.
To accomplish an extremely compact unit while securing the appropriate coupling of electrical energy it is further preferably provided that said fixtures for said electrodes are provided with connectors for the supply of RF/HF energy.
As mentioned above, the isolator confining said plasma is, to obtain the desired properties of the essentially point-like, low-energy plasma, possibly made from materials which are difficult to produce and expensive, so that it is desirable to limit material usage to the immediate vicinity of plasma production and keep material expenditure to a minimum. For further heat dissipation and for isolation or support of the isolator having said through-opening it is further proposed that said isolator confining said plasma is enclosed by a further isolator which centers the isolator and shields said electrodes from each other, whereby said isolator can be made of correspondingly less costly material, as for example, according to temperature, boron nitride or polyimide.
As already mentioned above, such a plasma can be used for widely varying applications, wherein in this context it is preferably proposed that plasma production is followed by a device for analyzing sample materials introduced into said plasma.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is subsequently illustrated by means of embodiments shown in the attached schematic drawings, in which:
FIG. 1 shows a sectional view of a first embodiment of a device according to the invention, to produce a RF/HF-induced, low-energy plasma to implement the method according to the invention;
FIG. 2 shows in enlarged scale a partial illustration of a modified embodiment of a device according to the invention to implement the method according to the invention;
FIG. 3 shows in an illustration similar to FIG. 2 a further modified embodiment of a device according to the invention to implement the method according to the invention;
FIG. 4 is a sectional view of another modified embodiment of a device according to the invention to implement the method according to the invention using the device as plasma reactor;
FIG. 5 is a sectional view of another modified embodiment of a device according to the invention to implement the method according to the invention using the device in connection with a mass spectrometer; and
FIG. 6 is a sectional view of another modified embodiment of a device according to the invention to implement the method according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In FIG. 1 two parallel, interspaced, ring- or disk-shaped electrodes are designated as 1 , and an isolator 2 , made for example of ruby, sapphire or generically any poorly or non-conducting oxide ceramic, is positioned between said electrodes, wherein the isolator 2 has a through-opening 3 , in which subsequently a plasma of small dimensions, which idealized can be regarded as point-like, is formed. Each electrode 1 has a through-opening 4 , which significantly exceeds the dimensions of through-opening 3 of said isolator defining the dimensions of the plasma to be produced, schematically shown as 17 , and which has about two to ten times the inside diameter of opening 3 . The electrodes 1 are mounted in schematically indicated fixtures 5 or 6 , through which, in a way not specifically shown, such as a spring-loaded contact pin, a connection is made with a generator for the supply of energy for ignition and maintenance of the plasma to be formed in the through-opening 3 of said isolator 2 , wherein a sample supply is designated as 7 . Said supply 7 , which for example may be formed from a quartz capillary tube, is surrounded by a further tube-like duct 18 , through which according to arrows 19 a plasma gas, such as for example helium or argon, and if need be an additive gas such as for example CO 2 , air, hydrogen or oxygen, is supplied to the region of electrodes and isolators.
From FIG. 1 it can be seen, that viewed with respect to the direction of flow of sample and plasma gas, 8 respectively 19 , another isolator 9 with a through-opening 10 , which is essentially equivalent to said through-opening 3 of said isolator 2 confining said plasma 17 , is positioned upstream of the first electrode. Said isolator 9 , positioned upstream with respect to flow 8 serves essentially the purpose of avoiding arcing of the plasma into supply 7 and damaging the surrounding elements. It can be further seen that an additional isolator 11 is positioned downstream of the second electrode 1 , viewed with respect to the direction 8 of plasma gas flow, the through-opening 12 of it being slightly smaller than the inner diameter of the adjacent electrode 1 . This downstream isolator 11 optimizes or exactly delimits the radiation produced by plasma 17 in said orifice 3 according to the requirements. By selecting the through-opening 12 at least slightly smaller than the through-opening 4 of the adjacent electrode 1 , protection of the electrode surface is improved and in particular the glow discharge on the electrode is spatially confined, which stabilizes the energy uptake of the entire plasma as well as the analytically interesting zone inside the through-opening of the middle isolator. To avoid sputtering effects the electrodes 1 can have rounded edges or must not have sharp edges. Further it is provided that, with respect to gas flow direction 8 , the downstream surface of isolator 2 is formed by an arc-shaped generating curve 13 , so that in the central region of isolator 2 a reduced thickness results, such that the essentially square dimensions of through-opening 3 , in a sectional view, favor the production of a spherical and, in an idealized designation, point-like plasma 17 .
The diameter of through-opening 3 in isolator 2 , which defines the dimensions of the plasma to be formed, can be less than 0.5 mm and for example approximately 0.1 to 0.2 mm. The diameter of the through-openings 4 of electrodes 1 , on the other hand, is for example 0.5 to 1 mm. The thickness of the electrodes 1 as well as of the isolators 2 , 9 , and 11 can be for example 0.5 mm, wherein because of the taper of the isolator 2 results in an accordingly reduced thickness of its central region.
It is therefore possible, with a simple construction, to provide a plasma source with very small and precisely definable spatial dimensions, such that at atmospheric pressure a low-power plasma with a power of for example below 20 W, and preferably between 5 and 10 W can be formed. Due to the low power it is furthermore possible to safely dissipate the resulting heat through the isolator 2 , wherein, as can be seen from FIG. 1, the isolator 2 is surrounded by a further isolator 14 , which on the one hand further dissipates the heat, and on the other hand safely shields the electrodes 1 , which are positioned on both sides of isolator 2 . Furthermore exhaust- or purge-openings 15 are indicated in fixture 6 , through which exhaust occurs according to arrows 20 .
Providing the fixtures 5 and 6 as well as said additional isolator 14 surrounding isolator 2 enables a secure positioning of the single elements having only small dimensions, wherein furthermore correspondingly gas-tight mounting for the single elements must be provided. The fixtures 5 , 6 have centering mounts or provide directly for the centering of through-openings 3 , 10 , 12 of the single elements to be brought into line, wherein a surrounding, isolating housing is designated schematically by 16 .
To achieve the corresponding tightness it may be provided that fixtures 5 or 6 are coated, for example gold plated, at least in the section of the sealing surfaces facing said electrodes 1 and/or isolators 2 , 9 , 11 .
The joining of the electrodes 1 with the isolators 2 , 9 , or 11 can be effected either mechanically by providing appropriate springs, by which said electrodes 1 and isolators 2 , 9 and 11 are pressed together, or alternatively known techniques of metal-ceramic bonding, for example soldering in vacuum or under hydrogen atmosphere, can be employed to achieve a correspondingly tight unit of said electrodes 1 and isolators 2 , 9 and 11 in fixtures 5 and 6 or within each other.
In the representations according to FIGS. 2 and 3, which in that case only show the sub-domain of the electrodes 1 as well as of the isolator 2 and, if this is the case, the isolators 9 and 11 which are positioned up- and downstream of it respectively, for same elements the reference numbers of the previous figure have been retained.
So the embodiment according to FIG. 2 provides that all of isolators 2 , 9 , and 11 are essentially disk-shaped having essentially constant thickness, whereas the embodiment according to FIG. 3 shows said isolator 2 confining plasma 17 tapered in its central region, in that a reduction of the thickness occurs on both sides along arc-shaped generating curves 13 . Such a perfectly centered positioning of said plasma between said two electrodes 1 facing the isolator 2 is possible. To achieve maximum field strength in the plasma region, said electrodes 1 are inclined towards the isolator 2 , i.e. formed as truncated cones.
In the varied embodiment, shown in FIG. 4, of a device used as plasma reactor, for plasma production again two electrodes 1 are provided, to which isolators 2 , 9 , and 11 , all having very small orifice cross-sections, are positioned in between, up- and downstream respectively. The mounting of the unit formed of the electrodes 1 and the isolators 2 , 9 , and 11 is again in fixtures 5 and 6 . Here the electrode 1 , being coupled with the fixture 6 and another, if needed also cooled fixture 21 , and positioned downstream with respect to flow directions 8 and 19 , is kept essentially at ground potential, whereas RF energy is coupled to fixture 5 , which houses the first electrode 1 , with respect to flow direction. The fixtures 5 and 6 are at least partially covered by further isolators 22 and 23 . When using the device shown in FIG. 4 as plasma reactor a sample is fed through a central inlet 7 , whereas plasma gas and, if needed, additive gases are fed through the duct 18 surrounding said sample inlet tube 7 , according to arrow 19 . With this a fixture 24 , positioned upstream and guiding sample and plasma gas, can be heated if need be.
Further it can be seen from FIG. 4 that through inlet openings 25 being provided in the fixture 21 a further additive gas can be introduced into the region of the electrodes 1 and isolators 2 , 9 , and 11 in a direction opposite to the feeding direction 8 or 19 of either sample or plasma gas respectively, wherein said additive gas serves for example cooling purposes, increases the pressure in the region of plasma production and simultaneously serves as transport gas. The reaction products, which subsequently are used for example for mass spectrometry or chemiluminescence, are transported according to arrow 27 through outlet 26 , which again may be in the form of a quartz capillary tube, if need be into a vacuum region, for further analysis.
For pertinent applications, in particular as ion source, an altered, with respect to the representation in FIG. 4, configuration of the power supply at the electrode, for example by exchanging connections for ground potential and supply of RF energy, may be selected.
In the embodiment according to FIG. 5, which is particularly useful with a mass spectrometer, for the same components again the reference numbers of previous figures have been retained. Likewise in this embodiment in particular the isolators 2 , 9 , and 11 haze very small through-openings, wherein again the second electrode 1 , viewed with respect to the direction of flow 8 or 19 , is connected to ground potential through the fixture or support 21 , whereas the first electrode 1 is fed with RF/HF energy across fixture 5 . The region of plasma production, as it is defined by the electrodes 1 and isolators 2 , 9 and 11 , is followed by a schematically shown shielding device 28 , wherein upstream of said shielding device for use in a mass spectrometer, according to arrow 29 , a primary vacuum is formed, whereby subsequently in the outlet region of reaction products, according to arrow 30 , a higher vacuum has to be provided.
If needed, supply of an additive gas can be provided also into the region immediately upstream of the last isolator 11 , viewed in the direction of flow. Further the upstream fixture 24 may again be provided with a heating appliance not shown in detail.
In the modified embodiment shown in FIG. 6 the reference numbers of the previous figures for same components have again been retained. So the isolator 2 again has a through-opening 3 which in turn confines plasma 17 . The inlet for a sample is designated as 7 . The isolator 2 for the confinement of said plasma 17 is again positioned between two ring- or disk-shaped electrodes, wherein the downstream electrode 1 again is formed similarly to the previous embodiments. In contrast to previous embodiments the upstream electrode is combined with the isolator positioned upstream of the first electrode, the resulting unit bein designated as 31 . The unit 31 has similarly to previous embodiments again an inlet- or through-opening 10 , which corresponds essentially to the through-opening 3 of the isolator 2 for confinement of plasma 17 . Starting from the through-opening 10 of the unit 31 said unit is provided with a conically expanding or essentially pot-shaped cavity 32 , such that overall, for the lines of electric flux to be formed between the electrodes to confine the plasma, a configuration essentially corresponding to the previous embodiments results. Herewith the conically expanding or pot-like cavity may be shaped, according to geometric requirements, having a depth corresponding to about twice its diameter.
The unit formed by the electrodes and isolators is again held in fixtures, which in the embodiment shown in FIG. 6 are designatd as 33 and 34 . From FIG. 6 it can be further seen that unlike the previous embodiments the isolator 2 for the confinement of plasma 17 extends to the fixtures 33 or 34 so wherefrom overall in the embodiment shown in FIG. 6 a reduced number of components results, which have to conform to each other or be connected to each other.
To increase the total power it can furthermore be provided that both said electrodes and the isolator 2 for the confinement of the plasma are each provided with an array of corresponding through-openings, wherein said through-openings are arranged in such a way that a focussing of the power emitted from single plasma sources to a common center or focus is feasible.
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A device for producing RF/HF induced low-energy plasma, in particular noble gas plasma, including a generator and a supply element for the plasma gas. The generator is coupled in a known manner to two, in particular, ring- or disk-shaped parallel, interspaced electrodes, each having at least one through-opening, and for at least one isolator to be positioned between the electrodes, the isolator having at least one particularly circular through-opening assigned to the through-opening of the electrode, whose through-opening is designed to confine the plasma formed by a plasma gas at a pressure of at least 0.01 bars, but preferably between 0.1 and 5 bars. The inside diameter of the through-opening of the electrodes is at least double, but especially approximately four to eight times that of the inside diameter of the through-opening of the isolator for confining the plasma.
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BACKGROUND OF THE INVENTION
1. Field of The Invention
The present invention relates generally to a computer system for performing graphics operations and, more particularly, to a computer graphics and animation system that includes a lighting subsystem for performing lighting.
2. Related Art
Computer graphics systems are commonly used for displaying two- and three-dimensional graphical representations of objects on a two-dimensional video display screen. Current computer graphics systems provide highly detailed representations and are used in a variety of applications.
In a typical computer graphics system, an object or model to be represented on the display screen is broken down into multiple graphics primitives. Primitives are basic components of a graphics display and may include, for example, points, lines, vectors, and polygons such as triangles and quadrilaterals. Typically, a hardware/software scheme is implemented to render, or draw, the graphics primitives that represent a view of one or more objects being represented on the display screen.
Generally, the primitives of a three-dimensional object to be rendered are defined by a host computer in terms of primitive data. For example, when the primitive is a triangle, the host computer may define the primitives in terms of the coordinates (X, Y, Z, and W) of its vertices, as well as the red, green and blue and alpha (R, G, B and α) color values of each vertex. Additional primitive data may be used in specific applications. Rendering hardware interpolates the primitive data to compute the display screen pixels that represent each primitive, and the R, G, and B color values for each pixel.
The basic components of a computer graphics system typically include a graphics interface and some specialized graphics system hardware. The graphics interface is provided generally to enable graphics applications located on the host computer to control efficiently the graphics system hardware. One of the more popular graphics interfaces is the OpenGL® standard, which provides an application program interface (API) to the graphics system hardware. (OpenGL is a registered trademark of Silicon Graphics, Inc.).
The OpenGL software interface provides specific commands that are used to specify objects and operations to produce interactive, three-dimensional applications. OpenGL is a streamlined, hardware-independent interface designed to be implemented on many different hardware platforms. As such, in computer systems that support OpenGL, the operating systems and graphics application software programs can make calls to the computer graphics system according to the standardized API without knowledge of the underlying hardware configuration.
The OpenGL standard provides a complete library of low-level graphics manipulation commands for describing models of three-dimensional objects (the "GL" of OpenGL refers to "Graphics Library"). This standard was originally based on the proprietary standards of Silicon Graphics, Inc., but was later transformed into an open standard that is used in high-end graphics-intensive workstations, and, more recently, in high-end personal computers. The OpenGL standard is described in the OPENGL PROGRAMMING GUIDE, version 1.1 (1997), the OPENGL REFERENCE MANUAL, version 1.1 (1997), and a book by Segal and Akeley (of Silicon Graphics, Inc.) entitled THE OPENGL GRAPHICS SYSTEM: A SPECIFICATION, version 1.1 (1995), all of which are hereby incorporated by reference in their entirety.
The graphics system hardware typically includes a geometry accelerator, a rasterizer, and a frame buffer. The graphics system may also include other hardware such as texture mapping hardware. The geometry accelerator receives primitive data from the host computer via the graphics interface. The primitive data defines the primitives that make up a view of the model to be displayed. The geometry accelerator performs transformations on the primitive data and may also perform such functions as lighting and view and model clipping for each primitive. The output of the geometry accelerator, referred to as rendering data, is used by the rasterizer and the texture mapping hardware to generate final screen coordinate and color data for each pixel in each primitive. The pixel data from the rasterizer and the pixel data from the texture mapping hardware, if available, are combined and stored in the frame buffer for display on the video display screen.
In the OpenGL lighting model, one or more light sources can be individually controlled. OpenGL typically allows 8 or more light sources to be defined for any particular scene. Many parameters can be defined for each of these light sources. For example, it is possible to define the position, focus, direction, attenuation and color of each light source. OpenGL uses the defined light source information to perform lighting of geometric primitives to produce optical effects on the scene.
OpenGL specifies that light sources are to be defined in object coordinates. The term "object coordinates" is used generally to refer to a coordinate system associated with the physical item to be modeled. OpenGL further specifies that the defined light source information is to be transformed from object coordinates to eye coordinates and stored in eye coordinates. The term "eye coordinates" is used generally to refer to a coordinate system associated with the way in which the object or model is viewed in the particular scene. Coordinates, coordinate space and space will be used interchangeably herein.
An illustration may be helpful to understand the difference between eye coordinates and object coordinates. For example, think of a book sitting on a desk. The eye coordinate system would be affixed to the desk with, for example, the X coordinate extending along the front of the desk, the Y coordinate extending along the left side of the desk and the Z coordinate extending perpendicularly above the surface of the desk. The object coordinate system would be affixed to the book itself in a convenient manner, for example so as to define X', Y' and Z' coordinate axes as extending along the edges of the book. Using a coordinate system fixed to the book is simply a matter of convenience that simplifies specification of the object being defined. In this example, since the object coordinate system is attached to the edges of the book, it is easy to define the book as extending, for example, two units along the X' direction, three units along the Y' direction and 1 unit along the Z' direction. After the object has been defined in object coordinates, the object coordinate data can be easily translated into eye coordinates simply by multiplying the object coordinate data by a transformation matrix. In OpenGL, a 4×4 matrix referred to as the "model view matrix" (M) is used to transform data from object coordinates to eye coordinates.
As noted above, OpenGL specifies that light sources are defined in object coordinates and that the light source information is to be transformed into eye coordinates and stored in eye coordinates. The stored light source information is used, in connection with vertex and normal data, to perform lighting. Both the light source information and the vertex and normal data must be in the same coordinate systems to perform lighting.
The light source information stored in eye coordinates may be used directly to perform lighting in eye coordinates or may be re-transformed from eye coordinates to object coordinates to perform lighting in object coordinates. Using the light source information to perform lighting in eye coordinates will be referred to herein as "eye coordinate lighting" whereas using the light source information to perform lighting in object coordinates will be referred to herein as "object coordinate lighting."
Since the light source information is stored in eye coordinates while vertex and normal data is provided in object coordinates, eye coordinate lighting requires that the normals and vertices of all primitives be translated from object coordinates to eye coordinates. Such a transformation is resource intensive and can form a processing bottleneck in the operation of the computer graphics system.
Object coordinate lighting is advantageous in that it enables lighting to be performed without transforming normal and vertex data from object coordinates to eye coordinates. Performing lighting in object coordinates, however, is not without price. As noted, to perform object coordinate lighting, it is necessary to re-transform the light source information from eye coordinates to object coordinates. Further, since the re-transformed light source information represented in object coordinates is a function of the model view matrix (M), this re-transformation of light source information must take place any time the model view matrix (M) changes. This re-transformation of light source information is also resource intensive and can itself form a processing bottleneck in the computer graphics system.
Accordingly, there is a need for an efficient technique to perform lighting in a computer graphics system. Further, there is a need for a geometry accelerator or graphics pipeline that can perform lighting efficiently for use in a computer graphics system.
SUMMARY OF THE INVENTION
The present invention is a computer graphics system including a lighting subsystem or a geometry accelerator that performs lighting efficiently by selecting dynamically the coordinate system in which lighting is to be performed. The present invention thereby minimizes required resources for performing lighting thus increasing the overall performance of the graphics system.
In one embodiment, the lighting subsystem utilizes a heuristic to determine whether lighting calculations should be performed in object coordinates or eye coordinates. This heuristic may take into account various factors, including the rate at which vertex data is delivered to the geometry accelerator and the frequency with which the model view matrix changes. Additionally, the heuristic may take into account a user's manual selection of one of the two lighting coordinate systems to thereby override the dynamic selection process. Likewise, the heuristic may take into account that another function, such as fogging or texture generation, will require transformation of vertex data from object coordinates to eye coordinates.
This invention is also related to a method for selecting dynamically lighting coordinates in a computer graphics system. This method generally includes the steps of selecting dynamically a lighting coordinate system, and performing lighting in the selected coordinate system. Light source information may be stored in one of the coordinate systems and may then be transformed, if necessary, to the selected coordinate system prior to performing lighting. The dynamic selection can take many objective indicia into account, such as whether functions other than lighting must be performed in either of the coordinate systems, whether transformation of the light source information is possible and the relative efficiencies of performing lighting in one coordinate system verses the other coordinate system.
The invention further relates to a lighting subsystem for use in a computer graphics system. The lighting subsystem preferably includes a dynamic light space selector for selecting dynamically a lighting space in which lighting is to be performed, a lighting processor for performing lighting and at least one switch operatively associated with and controlled by the dynamic light space selector to selectively enable the transformation of vertex or normal data from a first coordinate space to a second coordinate space prior to being input into the lighting processor. The term "coordinate space" will be used herein synonymously with "coordinate system" and the term "lighting space" will be used herein synonymously with "lighting system." The dynamic light space selector thus controls the switch to operatively determine which coordinate system will be used by the lighting processor to perform lighting.
In one embodiment, the dynamic light space selector first determines if a lighting space needs to be selected. If so, the dynamic light space selector determines whether performing lighting in object coordinates would be faster than performing lighting in eye coordinates. One way to do this is to observe the rate with which vertex data is supplied to the hardware. In OpenGL this may be accomplished by noting if the computer graphics system is operating in immediate mode or in another mode, such as display list, vertex array or draw array set. If the system is in immediate mode, eye coordinate lighting is selected. If the system is in a faster mode, object coordinate lighting is selected. Thus, the invention can dynamically select the lighting space to prevent the transformation of vertex data or light source information between lighting coordinate spaces from degrading or limiting performance of the graphics system.
In yet another embodiment, the invention stores the light source information in object coordinates before determining if lighting should take place in object coordinates or eye coordinates. If lighting is determined to take place in object coordinates and the model view matrix has not changed, lighting can take place in object coordinates using the light source information without requiring the transformation of any information through the model view matrix. In this situation, a substantial savings in resources may be accomplished.
This invention may be advantageously employed in a graphics accelerator formed in hardware, a graphics pipeline formed from software, or any combination of hardware, software and firmware.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is pointed out with particularity in the appended claims. The above and further advantages of this invention may be better understood by referring to the following description when taken in conjunction with the accompanying drawings, in which:
FIG. 1A is a block diagram illustrating different coordinate spaces in which graphical operations are performed when performing eye coordinate lighting;
FIG. 1B is a block diagram illustrating different coordinate spaces in which graphical operations are performed when performing object coordinate lighting;
FIG. 2 is a block diagram illustrating an exemplary embodiment of one aspect of the present invention which selects dynamically between two different coordinate spaces in which to perform lighting calculations;
FIG. 3 is a block diagram illustrating another exemplary embodiment of one aspect of the present invention which selects dynamically between two different coordinate spaces in which graphical operations can be performed when performing lighting;
FIG. 4 is a flowchart exemplifying one embodiment of the operation of selecting dynamically the coordinate system in which lighting is to be performed;
FIG. 5 is a flowchart exemplifying a possible heuristic that may be used at step 128 of FIG. 4 to select the coordinate system in which lighting is to be performed;
FIG. 6 is a functional block diagram of the OpenGL graphics system taken from the OpenGL reference manual in which dashed lines indicating the interconnection of components within and amongst the various blocks have been omitted;
FIG. 7 is a functional block diagram of a lighting subsystem operable with the OpenGL graphics interface that has been configured, constructed and arranged in accordance with an aspect of this invention;
FIG. 8 is a functional block diagram of a matrix control subsystem operable with the OpenGL graphics interface that has been configured, constructed and arranged in accordance with an aspect of this invention;
FIG. 9 is a functional block diagram of a clipping, perspective and viewport application subsystem operable with the OpenGL graphics interface that has been configured, constructed and arranged in accordance with an aspect of this invention; and
FIG. 10 is a flowchart exemplifying another embodiment of the operation of selecting dynamically the coordinate system in which lighting is to be performed.
DETAILED DESCRIPTION
To facilitate understanding of this invention, references is now made to FIGS. 1A, 1B and 2, which depict one implementation of transforming vertex data from object coordinates 108 to window coordinates 116. As shown in FIG. 1A, after a graphics primitive is assembled in object coordinates 108, the vertex data defining the primitive is transformed into eye coordinates 110 where lighting is performed, by multiplying the vertex data by a model view matrix (M) 100. The vertex data is then transformed from eye coordinates 110 to clip coordinates 112, where clipping is performed. The transformation is performed by multiplying the vertex data by a projection matrix (P) 102. After performing clipping, the vertex data is transformed to window coordinates 116 (window space) by performing perspective division 104 and multiplying the vertex data by viewport (V) and device (D) matrices 106. Typically this transformation to window coordinates 116 is performed by multiplying the vertex data by a concatenation of the viewport (V) and device (D) matrices. The vertex data in window coordinates is then forwarded for rasterization.
Instead of performing eye coordinate lighting, which requires the vertex data to be transformed to eye coordinates 110, it is sometime possible to perform object coordinate lighting. As shown in FIG. 1B, if lighting is performed in object coordinates and the vertex data is not otherwise required to be transformed to eye coordinates, the vertex data can be transformed directly to clip coordinates 112 by multiplying the vertex data by a concatenation of the model view matrix (M) and projection matrix (P) 101. After clipping is performed, the vertex data is transformed to window coordinates 116 using the same process described above with respect to FIG. 1A.
One aspect of this invention relates to a geometry accelerator that dynamically switches between lighting in eye coordinate space 110 and lighting in object coordinate space 108. This aspect is diagrammatically illustrated by the geometry accelerator in FIG. 2, in which dynamic light space selector 202 performs the functions of determining whether lighting calculations are to be performed in object coordinates 108 or eye coordinates 110. Once this decision has been made, lighting is performed in the selected coordinate space (eye or object coordinates). The vertex data is then transformed into clip coordinates 112 and, subsequently, into window coordinates 116 in the same manner described above with respect to FIGS. 1A and 1B.
The embodiments illustrated in FIG. 2 and otherwise described herein may be implemented in software, hardware or any combination of software, firmware and hardware. As used herein, the term geometry accelerator is intended to be generic to a graphics accelerator implemented in hardware and a graphics pipeline implemented in software.
The vertex data can take any one of a number of paths through the geometry accelerator. For example, as shown in FIG. 3, it is possible to process in parallel lighting in either object or eye coordinates and transformation of vertex data from object coordinates 108 to window coordinates 116. Clip planes are typically pre-computed and transformed from clip coordinates 112 to window coordinates 116. The results of the lighting, the transformed clip planes and transformed vertex data are then all forwarded for rasterization, clipping and perspective division. This parallel process may be especially suited for implementation in hardware.
The decision process performed by the dynamic light space selector 202 will now be explained more fully with reference to FIGS. 4 and 5, in which FIG. 4 is a flowchart exemplifying one embodiment of the operation of selecting dynamically the coordinate system in which lighting is to be performed, and FIG. 5 is a flowchart exemplifying a possible heuristic that may be used to select whether lighting should be performed at step 128 of FIG. 4. These figures are particularly useful for illustrating the determination process as it would be applied to software, however the following explanation applies equally to functions performed by hardware or firmware should the selection process be embodied in such an apparatus.
In one embodiment, the dynamic determination is implemented in software routines which interoperate with the components of the geometry accelerator to perform the graphics functions in accordance with the present invention. Such software routines typically reside in a computer memory and/or disk storage devices, and may be stored on any other computer-readable medium such as, for example, magnetic disk, compact disc or magnetic tape, and may be loaded into the computer or geometry accelerator using an appropriate peripheral device as known in the art. Preferably, this embodiment of the geometry accelerator is implemented in any well-known functional or object-oriented programming language such as C or C++. Those skilled in the art will appreciate that different implementations, including different function names, programming languages, data structures, and/or algorithms may also be used in embodiments of the present invention other than those described below. It should be further understood that the invention is not limited to a particular computer platform, particular operating system, particular processor, or particular high level programming language, and that the hardware components identified above are given by way of example only. The geometry accelerator may be implemented, for example, in dedicated hardware, firmware, or any combination thereof.
In OpenGL, as shown in FIG. 4 at block 124, light sources are defined in object coordinates. OpenGL requires that light sources be defined in object coordinates, however other application program interfaces ("APIs") may adopt other conventions. Examples of the types of information defined in a light source include the intensity, color, location, direction, focus and attenuation of the light beam. Additional parameters may be defined for any given light source depending on the particular API being used. Likewise, many of these parameters may be set by default by the API unless an alternative value is specified. Defining light sources is well within the level of skill in the art and will not be discussed further.
This light source information is then transformed to eye coordinates using the model view matrix (M) at step 126. A well-known matrix transformation is performed during this process. In OpenGL, this transformation is performed since OpenGL specifies that lighting operations are to take place in eye coordinates. The light source information is then stored in eye coordinates.
A decision is then made at step 128 to either perform lighting in eye coordinates or object coordinates. This determination is revisited each time there is a modal state change, for example a light source changes or the model view matrix changes. The heuristic associated with this decision process is illustrated more fully in FIG. 5 and is discussed in more detail below. If, in step 128, it is determined that lighting should occur in object coordinates, the light source information is re-transformed to object coordinates at step 130. Re-transformation of the light source information from eye coordinates to object coordinates requires the light source information to be multiplied by an inverse transpose of the model view matrix (M -T ). Re-transformations are commonplace operations and the implementation of a reverse transformation using the model view matrix is well within the skill of someone of ordinary skill in the art. Once the light source information has been re-transformed to object coordinates 130, lighting is performed in object coordinates at step 132. The operations associated with performing lighting in object coordinates is considered to be well known in the art.
If, on the other hand, it is determined at step 128 that lighting calculations should take place in eye coordinates, the vertex data is transformed into eye coordinates using the model view matrix (step 129) and lighting calculations are then performed in eye coordinates at step 134. As noted above, lighting in eye coordinates is the standard specified by OpenGL. The implementation of lighting in eye coordinates is considered to be well known in the art and will not be described further.
FIG. 5 illustrates one embodiment of the operations performed by the dynamic light space selector 202 at block 128 of FIG. 4 when determining whether lighting should take place in object coordinates or eye coordinates. As shown in FIG. 5, many factors may be considered in the determination of the coordinate system for performing lighting. As discussed in detail below, not all of these factors are essential to this determination. The selection of certain combinations of the particular factors described below may vary depending on the implemented API, the hardware, the expected operations to be performed by the graphics system and other factors.
Initially, at step 136, the dynamic light space selector 202 determines if a user has manually selected always to perform lighting in eye coordinates. This enables the dynamic light space selector 202 to accommodate a user's preference, if specified, causing the geometry accelerator to perform lighting operations in the user's preferred coordinate system. If eye coordinate lighting has been selected, the heuristic will return a "No" result at step 128 in FIG. 4 (step 150) and proceed to perform lighting in eye coordinates.
If the user has not selected eye coordinate lighting, a determination is made as to whether texture generation is enabled (step 138) or fogging is enabled (step 140). In OpenGL, texture generation and fogging both take place in eye coordinates and both require that vertex data be transformed from object coordinates to eye coordinates. In this situation there may be little benefit to performing lighting in object coordinates since this would not eliminate performing a transformation of vertex data to eye coordinates. Moreover, since performing lighting in object coordinates requires the light source information to be re-transformed from eye coordinates to object coordinates, performing lighting in object coordinates is actually more resource intensive than performing lighting in eye coordinates when either texturing or fogging has been enabled.
It is next determined if the right-most column of the model view matrix is equal to [0 0 0 1] (step 142). In the matrix shown below, the right most column of the matrix is occupied by the letter "D":
ABCD
ABCD
ABCD
ABCD
This factor is considered in one embodiment of the invention, because it has been observed that, in certain implementations, object coordinate lighting does not always behave properly if the right-most column of the model view matrix (M) is not equal to [0 0 0 1]. The discrepancies have been mainly observed with respect to positional lights. Accordingly, unless the right-most column of the model view matrix is equal to [0 0 0 1], lighting is preferably performed in eye coordinates. Other empirically determined criteria may serve as appropriate criteria for preferring one coordinate system over another coordinate system. These criteria may emerge over time or may be specific to the API being used.
At step 144, the heuristic determines if the model view matrix (M) changes often. Since every change in the model view matrix requires the light source information to be re-transformed from eye coordinates to object coordinates, at some point it becomes more burdensome for the geometry accelerator to process the re-transformation of light source information from eye coordinates to object coordinates than it is for the geometry accelerator to process the transformation of the vertex data from object coordinates to eye coordinates. In this situation, it is more efficient to perform lighting in eye coordinates.
Determining whether it is cost-effective to perform lighting in object coordinates or eye coordinates by monitoring the frequency with which the model view matrix changes may be performed, for example, by monitoring the number of pieces of vertex data processed between successive changes in the model view matrix. The amount of vertex data that must be processed between successive changes in the mode view matrix to make object coordinate lighting advantageous will depend on many variables, such as the number of light sources defined by the user (which relates to the amount of light source information), the speed of the graphics hardware and other factors. Accordingly, the number of vertices that must be processed between successive changes to the model view matrix must be determined empirically. A person of ordinary skill in the art could make this determination as a matter of course, given the individual parameters of the processing system being employed. In general, if the amount of time it takes to transform vertex data to eye coordinates and perform lighting on that transformed vertex data is more than the amount of time it takes to transform the light source information from eye coordinates to object coordinates and perform lighting on the same amount of vertex data, then it is advantageous to perform lighting in object coordinates. Otherwise, it is advantageous to perform eye coordinate lighting. This may be represented mathematically as:
x(TimeVT(x)+TimeECL(x))>TimeLIT+x(TimeOCL(x)) Equation 1
where,
x=number of vertices
TimeVT(x)=time to transform a single vertex from object coordinates to eye coordinates;
TimeECL(x)=time to perform eye coordinate lighting on a single transformed vertex;
TimeLIT=time to transform light source information to object coordinates; and
TimeOCL(x)=time to perform object coordinate lighting on a single vertex.
In many situations, the time it takes to perform eye coordinate lighting on a single transformed vertex will be the same as, or almost the same as, the time it takes to perform object coordinate lighting on a single vertex. Accordingly, in this situation, TimeECL(x)=TimeOCL(x), and Equation 1 can be simplified as shown below:
x>TimeLIT/TimeVT(x). Equation 2
Thus, in this situation, the number of vertices which must be processed between successive changes in the model view matrix must be greater than the time it takes to transform light source information to object coordinates, divided by the time it takes to transform a single vertex from object coordinates to eye coordinates.
The determination of whether the model view matrix changes too frequently (step 144) may involve monitoring the instantaneous number of vertices processed between successive changes in the model view matrix or may use another quantity, such as a running average of the number of vertices processed between successive changes in the model view matrix over a given number of successive model view matrix changes. The optimization of this process for various applications is well within the capabilities of persons of ordinary skill in the art.
The heuristic next determines whether object coordinate lighting has been manually selected (step 146). Selection of object coordinate lighting is similar to selection of eye coordinate lighting described above in connection with step 136. If object coordinate lighting is selected, the heuristic will return a "Yes" result at step 128 of FIG. 4 (step 154) if it is otherwise possible to perform object coordinate lighting. If object coordinate lighting has not been selected at step 146, the process proceeds to step 148.
In step 148, it is determined whether the transformation of vertex data from object coordinates to eye coordinates is acting as a constraint on the speed of processing vertex data, i.e., is forming a bottleneck. A bottleneck could be formed, for example, where the data was provided to the hardware faster than the hardware could transform the vertex data from object coordinates to eye coordinates.
In one embodiment, this determination is performed by analyzing the volume of data being transferred to the geometry accelerator, such as by considering the mode of the system. The mode of the system, in OpenGL, determines the speed with which the vertex data is transmitted from the OpenGL application ultimately to the hardware. In immediate mode, vertex data is individually transferred to the hardware using separate API calls. This is a relatively slow method of transferring data to the graphics hardware, that, given current processor speeds, usually provides the geometry accelerator with enough time to transform the vertex data from object coordinates into eye coordinates before subsequent vertex data is received. Thus, the transformation process from object coordinates to eye coordinates may not be a bottleneck on the speed of the computer graphics system when operating in immediate mode (given current processor speeds). Since, if this were the case, there is no advantage to be gained, it may be more efficient to perform lighting in eye coordinates and thereby avoid incurring costs associated with re-transformation of light source information from eye coordinates to object coordinates.
In other modes of operation, for example display list, vertex array or draw array set modes, vertex data arrives much faster. In these modes of operation, given current processor speeds, vertex data may arrive faster than the computer graphics system can transform the data from object coordinates to eye coordinates. Thus, the transformation of vertex data using the model view matrix may become a bottleneck when the computer graphics system is operating in one of these other modes. In such circumstances, lighting in object coordinates eliminates the transformation from object coordinates to eye coordinates thereby alleviating the bottleneck.
In the illustrated embodiment, if eye coordinate lighting is manually enabled (step 136), texture generation or fogging is enabled (steps 138 or 140), the right-most column of the model view matrix is not equal to [0001] (step 142), the model view matrix changes frequently (step 144) or the transformation of vertex data from object coordinates to eye coordinates is not causing a bottleneck in the process (step 148), then lighting is to be performed in eye coordinates. Accordingly, a "No" result is returned at step 128 in FIG. 4 (step 150). Otherwise, if object coordinate lighting is manually selected (step 146) or none of these conditions is met, it is determined that lighting should be performed in object coordinates.
Lighting in object coordinates is not possible in certain situations. For example, if the model view matrix is anisotropic, the matrix will not preserve angles between two vectors during re-transformation. Accordingly, re-transformation of light source information from eye coordinate space to object coordinate space may result in the introduction of errors into the lighting operation. Thus, object coordinate lighting cannot be performed if the model view matrix (M) is anisotropic. One of the more common situations that may cause the model view matrix to be anisotropic is where scaling takes place within the model view matrix such that the x, y and z axes are not all scaled by the same amount.
Accordingly, if it is determined that lighting should be performed in object coordinates, or if object coordinate lighting is manually selected (step 146), a determination is made as to whether the model view matrix is anisotropic (step 152). Since the determination of whether the model view matrix is anisotropic is resource intensive, this step is preferably relegated to the end of the heuristic.
It should be noted that when the model view matrix is anisotropic, the computer graphics system will perform lighting in eye coordinates and override the user's preference for performing lighting in object coordinates. Where the user's preference has been not accepted, the user may be notified optionally that the computer graphics system has performed lighting in eye coordinates instead of object coordinates. If the model view matrix is not anisotropic, lighting is to be performed in object coordinates and a "Yes" result is returned at step 128 of FIG. 4 (step 154).
Many of the determinations performed in FIG. 5 are optional when determining whether to light in object coordinates or eye coordinates. For example, it would be possible to use a heuristic that did not allow the user to mandate that either object coordinate lighting (step 146) or eye coordinate lighting (step 136) be used. Similarly, the heuristic could eliminate the determination of whether the model view matrix changed frequently compared to the number of pieces of vertex data processed (step 144). Indeed, one presently preferred exemplary embodiment of this invention does not make any such determination of how many pieces of vertex data are processed. Additionally, in an alternative embodiment, it may be mathematically possible to perform spherical texture mapping in object coordinates, thus removing step 140 from the heuristic. However, since an accurate re-transformation of light source information is not guaranteed when the model view matrix is anisotropic, it is strongly advisable to include the step 152.
FIGS. 6-9 illustrate a hardware embodiment of one aspect of this invention. FIG. 6 is a copy of the OpenGL graphics system taken from the OpenGL reference manual in which the dashed lines indicating interconnection of components within and amongst the various blocks have been omitted. In one embodiment of this invention, three subsystems of the OpenGL graphics system are modified. Specifically, the lighting subsystem 200, the matrix control subsystem 300, and the clipping, perspective and viewport application subsystem 400 are all modified in this embodiment. These three subsystems are set forth respectively in FIGS. 7-9.
As shown in FIG. 7, the lighting subsystem 200 selectively receives normal data on line 203 and vertex data on line 205 for processing with calculated lighting information in the lighting processor 212. In accordance with the present invention, a dynamic light space selector 202 determines whether lighting is to take place in eye coordinates or object coordinates. If the dynamic light space selector 202 determines that lighting should take place in eye coordinates, the dynamic light space selector 202 provides a signal on line 201 to switches 204 and 206 to cause the normal data on line 203 and vertex data on line 205 to be input to matrix multipliers 208 and 210 respectively. Matrix multipliers 208 and 210 receive the model view matrix M from the model view matrix stack 310 in matrix control subsystem 300 and perform matrix multiplication on the normal and vertex data, respectively, to transform the data from object to eye coordinates. Lighting in eye coordinates then takes place using this normal and vertex data in eye coordinates in the lighting processor 212.
If, on the other hand, the dynamic light space selector 202 determines that lighting should take place in object coordinates, the dynamic light space selector 202 provides a signal on line 201 to switches 204 and 206. In this situation, switches 204 and 206 cause the normal and vertex data to bypass the matrix multipliers 208 and 210, and to thereby be input directly to the lighting processor 212 where lighting takes place in object coordinates.
The dynamic light space selector 202 provides a signal on line 207 to the lighting processor 212 to control the lighting processor 212 to perform lighting in object coordinates or eye coordinates. If the computer graphics system is to perform lighting in eye coordinates, light source information from light parameters 214 is provided to the lighting equations 216 without being re-transformed into object coordinates. If, however, the computer graphics system is to perform lighting in object coordinates, the light source information from light parameters 214 is re-transformed into object coordinates prior to being provided to the lighting equations 216. A re-transformation of the light source information to object coordinates may be accomplished by multiplying the light source information by the inverse transpose of the model view matrix (M -T ). The dynamic light space selector provides a signal on line 207 to control whether the light source information is provided to the lighting equations 216 in eye coordinates or is first re-transformed from eye coordinates to object coordinates. A switch and matrix multiplier (not shown) in light parameters 214 can be used, for example, to select dynamically between these two coordinate systems.
To transform vertex data from object coordinates to clip coordinates, vertex data on line 205 is also received by a concatenated matrix transform 218 at an input b, multiplied by a concatenation matrix MP (see FIG. 8), and is output (in clip coordinates) at an output MP*b. The output of the concatenated matrix transform 218 is input to the primitive assembly (not shown) and then passed to the clipping, perspective and viewport application subsection illustrated in FIG. 9.
As shown in FIG. 9 and as is well known, the clipping, perspective and viewport application subsystem 400 receives polygons, line segments and points raster positions from the primitive assembly (not shown) and performs model clipping and view clipping. Since the vertex data has been previously transformed directly from object coordinates to clip coordinates by the concatenated matrix transform 218 (FIG. 7), both model clipping and view clipping are performed in clip coordinates. Alternatively, if clipping is to be done in window coordinates (as shown in FIG. 3) the vertex data can be transformed directly from object coordinates to window coordinates and the clip planes can be transformed directly from clip coordinates to window coordinates.
In the standard OpenGL graphics system, model clipping was performed in eye coordinates and view clipping was performed in clip coordinates. Accordingly, the OpenGL graphics system provided that a transformation be performed from eye coordinates to clip coordinates after model clipping had taken place. In a graphics processor incorporating the present invention, since both model and view clipping are performed in clip coordinates (or window coordinates), it is no longer necessary to perform a transformation on the vertex data between clipping operations. Accordingly, to illustrate this difference from a standard OpenGL graphics system, dashed boxes 220 and 312 have been inserted indicating that the matrix transformer 220 and prospective matrix stack 312 have been removed from the clipping, perspective and viewport application subsystem 400. Further, the concatenated matrix MP is input to the concatenator matrix transform 224 from matrix control 300 to transform directly the clip planes from object coordinates to clip coordinates.
As shown in FIG. 7, the matrix control subsystem 300 provides matrix control to the perspective matrix stack 312, the model view matrix stack 310 and to the texture matrix stack (not shown). The OpenGL graphics system provided for the same level of control over these three matrix stacks. However, since the perspective matrix stack 312 was previously only used by the clipping, perspective and viewport application subsystem 400 shown in FIG. 9, the OpenGL graphics system included the perspective matrix stack 312 as part of that subsystem 400. Since clipping, in this embodiment, is done wholly in clip coordinates, the clipping, perspective and viewport application subsystem 400 no longer requires input from the perspective matrix stack 312. Accordingly, the perspective matrix stack 312 has been moved from the clipping, perspective and viewport application subsystem 400 to the matrix control subsystem 300.
The model view matrix M is provided from the model view matrix stack 310 to the lighting subsystem 200 to control the transformation of normal and vertex data from object coordinates to eye coordinates in the normal data and vertex data matrix multipliers 208 and 210 respectively.
The output of the perspective matrix stack 312 (the perspective matrix P) is combined with the output of the model view matrix stack (the model view matrix M) in the concatenator 314. The concatenator 314 multiplies the model view matrix M with the perspective matrix P to form concatenated matrix (MP). Note, in this regard, that matrix multiplication, while associative, is generally not commutative, i.e., M×P is not typically equal to P×M. The concatenator thus should preferably multiply M×P to form the concatenated matrix (MP). The concatenated matrix MP is provided to the concatenated matrix transform 218 in lighting subsystem 200 to control the transformation of vertex data from object coordinates to clip coordinates, and is provided to the concatenated matrix transform 224 in clipping, perspective and viewport application subsystem 400 to control the transformation of clip plan data from object coordinates to clip coordinates.
FIG. 10 illustrates an alternative embodiment of the lighting coordinate selection method of the present invention that further minimizes the amount of information which must be transformed to perform lighting operations. According to the OpenGL standard, and as shown in FIG. 4, light source information is defined in object coordinates (step 124) and then is transformed to eye coordinates (step 126).
By contrast, in the embodiment illustrated in FIG. 10, after the light sources are defined in object coordinates (step 500), the light source information is not transformed immediately to eye coordinates, but rather is stored initially in object coordinates (step 502). A determination is then made whether to perform lighting in object coordinates or eye coordinates (step 504). Since this step is analogous to the determination performed at step 128 of FIG. 4 and as described in greater detail with respect to FIG. 5, it will not be described further at this time.
If it is determined that lighting operations should be performed in eye coordinates, the light source information is transformed to eye coordinates (step 514) and the vertex and normal data is transformed from object coordinates to eye coordinates using the model view matrix (step 516). Lighting is then performed in eye coordinates using the transformed vertex data and transformed light source information (518).
If, on the other hand, it is determined at step 504 that lighting should take place in object coordinates, an inquiry is made as to whether the model view matrix has changed since the light sources were defined. If the model view matrix has changed since the light sources were defined, the light information is transformed from object coordinates to eye coordinates using the original model view matrix and then re-transformed from eye coordinates to object coordinates using the new model view matrix.
If, however, the model view matrix has not changed since the light sources were defined, a transformation of information using the model view matrix and a re-transformation of using the inverse transpose of the model view matrix would not change the original light source data, since a matrix times its inverse transpose yields the identity matrix. Thus, in this situation, it is possible to perform lighting directly without transforming the lighting information at all. This results in an additional savings by decreasing the resources required to perform object coordinate lighting after the light sources have been defined but before the model view matrix changes. Specifically, by storing the light source information in object coordinates, it becomes possible to perform object coordinate lighting without performing any transformation (of vertex data or lighting data) using the model view matrix. The elimination of these transformation would, accordingly, be expected to result in an increase in overall speed of the graphics system.
The above description was provided using the OpenGL graphics interface to describe implementation of a lighting scheme whereby the coordinate system in which lighting is to be performed is dynamically determined. Other graphics application interfaces may have additional or different functionality thus requiring modifications to be made to the heuristic or other aspects of the implementation of this invention.
Likewise it may be possible to select dynamically those factors which are used by the heuristic which are used to select dynamically the lighting space in which lighting is to take place. For example, the computer graphics system could, in real time, evaluate how well the current heuristic was performing and modify the heuristic itself depending on the current operating parameters of the computer graphics system. Alternatively, the computer graphics system could be monitored, for example, to determine how frequently each or any step of the heuristic determines that eye coordinate lighting should be selected. The computer graphics system could then modify, on a real time basis, the organizational structure of the heuristic to optimize the order of the steps. In this manner, operation of a given heuristic may be optimized to thereby achieve enhanced characteristics and minimize the amount of resources required to be expended to implement the heuristic itself.
It should be understood that various changes and modifications of the embodiments shown in the drawings and described in the specification may be made within the spirit and scope of the present invention. Accordingly, it is intended that all matter contained in the above description and shown in the accompanying drawings be interpreted in an illustrative and not in a limiting sense. The invention is limited only as defined in the following claims and the equivalents thereto.
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A computer graphics system includes a lighting system that performs lighting efficiently by selecting dynamically the lighting space in which lighting calculations are to be performed to thereby minimize resources required to be expended to perform lighting. A particular preferred lighting coordinate system is then selected, based upon particular criteria, and the light source information is transformed to the selected coordinate system (if necessary) where lighting is performed. The dynamic selection can take many objective indicia into account, such as whether functions other than lighting must be performed in either of the coordinate systems, whether transformation of the lighting information is possible and the relative efficiencies of performing lighting in one coordinate system verses the other coordinate system. In another aspect, a lighting subsystem for use in a computer graphics system includes a dynamic light space selector for selecting dynamically a lighting space for performing lighting, a lighting processor for performing lighting and at least one switch operatively associated with and controlled by the dynamic light space selector to selectively enable the transformation of data from a first coordinate space to a second coordinate space prior to being input into the lighting processor. The dynamic light space selector thus controls the switch to operatively determine which coordinate system will be used to perform lighting in the lighting processor.
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TECHNICAL FIELD
[0001] The present invention belongs to the field of the comprehensive utilization of straw resources, and particularly relates to a process for producing a bio-based product from straw hemicellulose and fully utilizing the components thereof.
BACKGROUND ART
[0002] China is a major petroleum import country, and about 50 percent of petroleum is imported each year. Besides the majority of the petroleum resource is used as fuels for production and refining, there is also a considerable part of the petroleum resource used for the production of chemicals.
[0003] With the gradual depletion of petroleum resources, the focus of energy research has been shifted to biofuels in the whole world. In addition to the clean energy sources such as methane and hydrogen, biofuels-butanol wins the favor of more people and is known as the third-generation biofuels, because of its advantages, such as capable of being mixed with gasoline in any ratio, not requiring any reconstruction for vehicles, having high economic value, effectively improving the fuel efficiency and mileage of vehicles, and so on. At the aspect of bio-based chemicals, attention has been widely paid to some of the key platform compounds, such as 2,3-butanediol currently, which as an additive, can be widely applied to inks, cosmetics, lotions, plasticizers, drug and other industries, but also has the performance of liquid fuels. In addition, lactic acid, as an important chemical, is also widely used in the processing of food, pharmaceutical, cosmetics, chemical materials and agricultural products. At present, most of these bio-based products are produced from corn, wheat and other starch materials as the major raw materials through a saccharification and fermentation process. However, the production of biofuels from food supplies not only cannot meet the needs of the community, but also will endanger food safety. It was reported by some researchers that even if all the corn and soybeans grown in the United States were used for the production of bio-energy, only 12% of U.S. gasoline demand and 6% of U.S. diesel oil demand could be satisfied. In fact, corn and soybeans cannot be all used to produce biofuels, because their priority use is for foodstuff, feedstuff and other economic needs.
[0004] China has very rich straw resources. Its annual output is about 700 million tons. However, most of the straws have not been effectively utilized till now. If we can use bio-refining technologies to produce chemicals, materials and fuels from straws, as the main raw material, the petroleum import pressure can be sufficiently alleviated in China. Therefore, exploring the fermentation of non-foodstuff plants such as straws, as the raw materials is an important route to achieve the sustainable production of bio-based products.
[0005] The main components of the cell walls of straws include cellulose, hemicellulose and lignin. Lignin together with hemicellulose are filled as an intercellular substance between the microfine fibers in the cell walls, reinforce the cell walls of the wood tissue, and are also present in the intercellular layer to allow the adjacent cells to be bonded together. Cellulose, as a chained polymer of glucoside linked by beta-1,4-glycosidic bond, can be used for the production of all kinds of chemical and material products, and can also be biodegraded into glucose for the production of a variety of fermentation products. Hemicellulose is a general designation for a large class of polysaccharides having different structures, such as pentosan, poly-arabinose, polymannose, polygalactose, wherein the main component is pentosan. The degradation products of hemicellulose mainly include xylose, arabinose, mannose, and a small amount of glucose, can be converted by microbes into biofuels such as ethanol, butanol, methane and hydrogen, and can also be fermented into butanediol, xylitol, lactic acid and single-cell protein. Lignin, as an important chemical product itself, is a class of complex amorphous materials of phenylpropanes units linked by ether bonds and carbon-carbon-bonds.
[0006] Currently, the main problems up against the use of straw to produce biofuels include the high costs for raw material pretreatment and enzymatic hydrolysis, as well as the low utilization value of the raw materials. The reasons for that are shown as follows. First, people tend to only pay attention to the use of the cellulose that is difficult to be degraded in straw, but turn a blind eye to the hemicellulose resource in an amount of 25% -35% of straw. In fact, steam explosion pretreatment and dilute acid pretreatment can be used to effectively degrade and remove hemicelluloses but remain lignin and cellulose. Then after an alkali treatment, the lignin and cellulose can be obtained. Straw cellulose, due to its special chemical structure, has a great market value in the material product industry. However, in practice, people tend to degrade straw cellulose completely, while ignoring its functional features, thus resulting in the high degradation cost and low production value. In addition, the lignin in straw is often used as fuel for direct combustion. Nevertheless, in fact, the processed lignin can be made into a chemical raw material with a high added value.
[0007] Comparison of the disclosed invention patents is shown as follows. U.S. Pat. No. 2,481,263 discloses a process of direct fermentation of acetone, butanol and ethanol from pentose acid hydrolyzate. The key innovation of this invention is that fine iron powder and limestone are used for the detoxification of the acid hydrolyzate, then the xylose solution is fermented after flash-steam sterilization. In this patent, a great amount of iron powder and limestone are required in the detoxification process, and no comprehensive utilization of the raw materials is taken into consideration. Therefore, as the environmental pressure increases gradually, it cannot be used for industrial production apparently. U.S. Pat. No. 4,424,275 discloses a method of the continuous production using butanol, characterized in that butanol is first continuously extracted by a solvent extraction method, and then the extraction solvent is recycled in combination with distillation. Although this patent involves some innovation to the fermentation method, the issues regarding the raw materials are barely considered. U.S. Pat. No. 4,539,293 discloses a method of co-fermenting Clostridium pasteurianum and C. Butylicum, so as to improve butanol production and the proportion of the butanol in the solvent. However, no innovation was made to the raw materials for fermentation. U.S. Pat. No. 4,649,112 discloses a method of directly fermenting corn bran fiber or a mixture of corn bran fiber and xylan to obtain butanol by C. acetobutylicum. Although the pre-hydrolysis step is omitted in this method, the fermentation microbes mainly utilize the starch contained in the raw materials for fermentation, which also limits the types of raw materials for butanol fermentation. U.S. Pat. No. 4,777,135 discloses a method to promote butanol fermentation by adding a fluorocarbon compound in the butanol fermentation broth. However, this patent barely involves the source of the raw materials. U.S. Pat. No. 5,063,156 ameliorates butanol fermentation from the point of view of the fermentation methods, and improves the proportion of butanol in all the products during the butanol fermentation process by means of the combination of continuous fermentation and batch fermentation. Chinese Patent with Publication No. CN 101434968A discloses a method for producing fuel butanol from tapioca. Even though cassava is a non-food raw materials, the cultivation of cassava still requires vast lands. It was also reported that since the production of cassava alcohol began in Guangxi, the price of cassava has been highly raised, which causes the cost of cassava alcohol is higher than its market price. In this case, the same problem will also be faced by the production of butanol from cassava. Therefore, the exploration of butanol production from straw-cellulose raw materials will be a better production route. Chinese Patent with Publication No. CN101358218A discloses a method to produce pentose together with acetone, butanol and ethanol from straw. Chinese Patent with Publication No. CN101358214A discloses a method to produce furfural together with acetone and butanol from straw. In both of these patents, straw is used as the raw material; after hydrolysis, the hemicelluloses in the straw is converted into five-carbon sugar or furfural; the remaining hydrolyzate is, after treated, converted into glucose through enzymolysis; then fermentation is conducted to produce butanol. Although by this method butanol can be produced, now it seems that the degradation of cellulose to glucose requires cellulase, which involves a very high production cost. As a result, using this route to the production of butanol, the production cost is high. When the butanol is used as a fuel, the price cannot be accepted by the market.
[0008] Therefore, it is desired to find a cheaper and easier process for pretreating raw materials, so as to improve the efficiency of utilization and degradation of straw, improve product yield and reduce production costs at the same time.
DISCLOSURE OF THE INVENTION
[0009] Due to the high cost for the degradation of straw cellulose, as well as the resulted high cost for the fermentation of products such as biofuels, etc., an object of the present invention is to provide an improved straw pretreatment method, so as to provide a new route for the production of low-cost straw fermentation product and achieve the high-value utilization of straw resources.
[0010] To achieve this object, the present inventors have carried out extensive research work, and found that hemicellulose can be directly used as a raw material for fermentation, so as to reduce the cost of production of bio-based products and to simplify the utilization of cellulose and lignin by using its characteristics which is susceptible to be degraded by steam explosion pretreatment and dilute acid pretreatment. At the same time, the inventors unexpectedly found that when straw is pretreated in a combination of steam explosion and dilute acid in a certain condition, a better utilization of straw can be achieved.
[0011] Accordingly, the present invention includes three aspects: the degradation of the straw hemicellulose, the preparation of bio-based products from a straw hemicellulose degradation liquid, and the separation of the cellulose and lignin of straw. In a first aspect, the present invention is to provide a method of degrading straw hemicellulose, and the method comprises two treating modes: (1) water immersion, steam explosion treatment in combination with acid treatment; and (2) acid soak in combination with steam explosion treatment.
[0012] The mode which involves water immersion, steam explosion treatment in combination with acid treatment includes the following steps:
1) straw pretreatment: straw is soaked in water; 2) steam explosion process: the straw soaked in step 1) is fed into a steam-explosion tank and maintained under a steam-explosion pressure for a steam-explosion period; then the steam-exploded straw material is released; 3) acid treatment: the steam-exploded straw material obtained in step 2) is fed into an acid-hydrolysis tank pre-filled with a dilute acid and subjected to acid hydrolysis to generate a hydrolyzed material; and 4) product collection: after acid hydrolysis, the hydrolyzed material obtained in step 3) is filtered to generate a hydrolyzate liquid, and the hydrolysis residue is collected and extruded using an extruder to obtain a solid material.
[0017] The mode which involves acid soak in combination with steam explosion treatment includes the following steps:
1) straw pretreatment: straw is soaked in a dilute acid; 2) steam explosion process: the straw soaked in step 1) is fed into a steam-explosion tank and maintained under a steam-explosion pressure for a steam-explosion period; then the steam-exploded wet straw material is released; and 3) product collection: the steam-exploded wet straw material in step 2) is added to and soaked in water thoroughly, the steam-exploded wet straw material is extruded using an extruder to obtain a solid material, and the extrusion liquid is collected simultaneously and filtered to generate a clarified hydrolyzate liquid.
[0021] In a second aspect, the present invention is to provide a method of preparing bio-based products from a straw hemicellulose degradation liquid, and the method comprises the following steps of:
a) distilling the hydrolyzate liquid obtained by the method according to the invention under a reduced pressure, collecting and refining the distillate to obtain furfural and acetic acid, wherein the distilled residue liquid is a sugar solution; and b) preparing a fermentation medium from the sugar solution obtained in step a) after detoxification treatment by adding nitrogen source therein, inoculating and culturing a seed solution of a fermentation bacterium in the logarithmic growth phase.
[0024] In a third aspect, the present invention is to provide a method of separating cellulose and lignin of straw, and the method comprises the following steps:
1) the solid material obtained from the extrusion of the steam-exploded straw is fed to an alkaline extraction tank and incubated at a temperature of 150° C. for 4 h upon the addition of a 2 wt % NaOH solution; a solid material is extruded using an extruder and alkaline extraction liquid and alkaline extraction residue are obtained; the alkaline extraction liquid passes through a PVC ultrafiltration membrane to recover NaOH; the solid material obtained by ultrafiltration is collected and dried to obtain lignin; 2) the lignin is used for the production of phenolic resin adhesive, a phenolic resin, a rubber reinforcing agent, a nano-carbon fiber; and 3) the alkaline extraction residue passes through a mechanical carding machine to separate long fibers and short fibers, wherein the long fibers are used for the production of sodium hydroxymethyl cellulose and polyether polyols and the short fibers are degraded into glucose while cellulase is added.
[0028] The present invention has the following beneficial effects:
[0029] 1 The pretreatment of straw by combination of steam explosion and acid hydrolysis allows the hemicelluloses contained therein to be sufficiently released into the hydrolyzate liquid, increases the yield of furfural and acetic acid and the concentration of the sugar solution, and also can improve efficiency of producing all kinds of fermentation products from the sugar solution.
[0030] 2. The direct utilization of the easily degraded hemicellulose in straw as a fermentation raw material to produce a fermentation product such as butanol, etc. avoid the problem in prior art (see the butanol fermentation routes disclosed in CN101358218A and CN101358214A), i.e. a great amount of cellulase is required for the fermentation of butanol from glucose obtained by cellulose enzymolysis. As a result, the raw-material cost for butanol can be effectively reduced, and a very good solution is provided to the issue in prior art (see U.S. Pat. No. 4,649,112 and the Chinese invention patent CN10143968A), i.e. only corn bran fiber, or a mixture of corn bran fiber and xylan or tapioca can be used in butanol fermentation methods.
[0031] 3 No waste or pollution is generated during the whole process. All components of straw are subjected to a high-value utilization (see FIG. 1 for the process). Lignin can be used for the production of phenolic resin adhesive, a phenolic resin, a rubber reinforcing agent, a nano-carbon fiber. Cellulose can be used for the production of sodium hydroxymethyl cellulose, bio-polyether polyol and materials. In the present invention, cellulose and lignin are obtained by alkaline extraction and removal of straw hemicelluloses, these cellulose and lignin are different from the cellulose and lignin derived from traditional paper making methods. Because the alkali is in a small amount and extraction period is short, the lignin prepared by the present invention has a high purity and uniform molecular weight, and is conducive to liquefaction into a polyether polyol and phenolic resin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a diagram showing the preparation of bio-based products through degradation of straw hemicellulose using the method of the invention and the full utilization of the straw components, wherein corn straw are used as the example; and
[0033] FIG. 2 shows the steps in the two embodiments of degradation of straw hemicellulose provided in the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] The present invention is to provide a process of producing bio-based products from the degradation liquid of straw hemicellulose (hereinafter referred to as “the method of the present invention”), and this method comprises three steps of degrading straw hemicelluloses; producing bio-based products from the degradation liquid of straw hemicelluloses; and separating cellulose and lignin of straw.
[0035] In the method of the present invention, the degradation of the straw hemicellulose can be carried out by two approaches, see Step I and Step II in FIG. 2 .
[0036] In the Step I shown in FIG. 2 (i.e. water immersion, steam explosion treatment in combination with acid treatment), the processing of straw includes the following steps: first, straw is soaked in water for a period of time and then subjected to steam-explosion treatment after fed into a steam-explosion tank; the obtained steam-exploded straw is then fed into an acid-hydrolysis tank and subjected to an acid treatment therein. After the acid treatment, the steam-exploded straw and hydrolyzate liquid are separated through a plate filter to generate a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material.
[0037] Accordingly, in the first embodiment of the present invention, the method of the present invention comprises the following steps:
1) pretreating straw, wherein the straw is soaked in water, wherein the mass ratio of straw to water is 1:1 to 1:3, the soaking temperature is 15° C. to 90° C., and the soaking period is 10 mins to 60 mins; 2) conducting steam explosion, wherein the straw soaked in step 1) is fed into a steam-explosion tank, and maintained under a certain steam-explosion pressure for a steam-explosion period; then the steam-exploded straw material is released, wherein the steam-explosion pressure is 0.3 MPa to 2.0 MPa, preferably 0.5 to 1.0 MPa, and the pressure maintenance period is 1 mins to 10 mins; 3) performing an acid treatment, wherein the steam-exploded straw material obtained in step 2) is fed into an acid-hydrolysis tank pre-filled with a 0.8 to 1.6% dilute acid and subjected to acid hydrolysis to generate a hydrolyzed material, wherein in the acid-hydrolysis tank, the mass ratio of the steam-exploded straw to the dilute acid is 1:2 to 1:7, the reaction temperature is 75° C. to 105° C., and the reaction time is 10 mins to 60 mins; and 4) collecting the product, wherein after acid hydrolysis, the hydrolyzed material obtained in step 3) is filtered to generate a hydrolyzate liquid, and the hydrolysis residue is collected and extruded using an extruder to obtain a solid material.
[0042] In the Step II shown in FIG. 2 (i.e. acid soak in combination with steam explosion treatment), the processing of straw includes the following steps: first straw is soaked in a dilute acid for a period of time and then subjected to steam-explosion treatment after fed into a steam-explosion tank. The resultant steam-exploded wet straw material is passed through an extruder to separate a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material.
[0043] Accordingly, in the second embodiment of the present invention, the method of the present invention comprises the following steps:
1) pretreating straw, wherein the straw is soaked in a dilute acid, wherein the mass ratio of straw to the dilute acid is 1:1 to 1:3, the concentration of the dilute acid is from 0.01 to 0.1 wt %, preferably from 0.02 to 0.05 wt %, and the soaking period is 10 mins to 60 mins; 2) conducting steam explosion, wherein the straw soaked in step 1) is fed into a steam-explosion tank, and maintained under a steam-explosion pressure for a steam-explosion period; then the steam-exploded wet straw material is released, wherein the steam-explosion pressure is 0.3 MPa to 1.0 MPa, and the pressure maintenance period is 0.5 min to 3 mins; and 3) collecting the product, wherein the steam-exploded wet straw material in step 2) is added to and soaked in water in the weight equal to 4-10 times of that of the dry straw material at 70° C. for 30 mins to 1 h, the steam-exploded wet straw material is extruded using an extruder to obtain a solid material, and the extrusion liquid is collected simultaneously and filtered to generate a clarified hydrolyzate liquid.
[0047] The main components of straw include cellulose, hemicellulose and lignin, wherein the first two components can be degraded into monosaccharides for production of butanol through fermentation. However, the degradation of cellulose requires a rigorous condition, and consumption of a large amount of cellulase is necessary for its effective degradation. As such, production of butanol and other chemicals from the hexose in straw faces the pressure of high costs. However, since straw hemicellulose is susceptible to degradation, it can be sufficiently degraded into monosaccharides by way of steam explosion or dilute acid treatment, then the monosaccharides can utilized by bacteria to produce butanol, butanediol, lactic acid, methane, hydrogen and other products. After the removal of hemicellulose from straw, the residue can be subjected to an alkaline treatment to effectively separate cellulose and lignin. The obtained cellulose and lignin can, after appropriate processing, be converted into cellulose derivatives and lignin derivatives with high added values.
[0048] Therefore, the straw used in the method of the present invention can be selected from a very large scope, for example, can be one or more selected from corn straw, rice straw, wheat straw, bagasse, corn cobs, sorghum straw, miscanthus sinensis, imperata cylindrica, ramie, jute, abutilon, marijuana, flax, Apocynum, kenaf, cotton stalks, banana stems, pineapple leaf, or ponnisetum hydridum. Among others, from the point of view of the hemicellulose content, corn straw, corn cobs, bagasse and marijuana are preferred.
[0049] In the embodiments described above, in the step 1) of pretreating straw, air-dried straw (water content is less than 3%) is generally cut into small pieces in the size of 3-10 cm.
[0050] In the embodiments described above, the dilute acid is typically selected from inorganic acids, such as one or more selected from the group consisting of dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid, and dilute phosphoric acid. A person skilled in the art can make the appropriate choices according to the specific process conditions, the cost of raw materials and other factors.
[0051] In another embodiment of the present invention, the method of the present invention further comprises the following steps of
a) distilling the hydrolyzate liquid obtained by the method of the present invention under a reduced pressure, collecting and refining the distillate to obtain furfural and acetic acid, wherein the distilled residue liquid is a sugar solution at a concentration of 20 g/L 150 g/L by weight of xylose and glucose; and b) adding the sugar solution obtained in step a) to a fermentation medium made from nitrogen source after a detoxification treatment, and inoculating a seed solution of a fermentation bacterium in the logarithmic growth phase at a concentration of 10% by weight of the medium, wherein the detoxification treatment is one or more selected from the group consisting of electrodialysis, macroporous resin adsorption and activated carbon adsorption, the nitrogen source is one or more selected from the group consisting of corn milk, corn extracts, yeast extract, peptone, (NH 4 ) 2 HPO 4 , (NH 4 ) 2 SO 4 and ammonium acetate, and the fermentation bacterium is Clostridium acetobutylicum, Actinobacillus succinogenes, Klebsiella, Lactobacillus or Clostridium butyricum.
[0054] In a preferred embodiment, the processing condition for the electrodialysis includes a temperature of 15 to 30° C. and a current density of 600˜1000 A/m 2 ; the processing condition for the macroporous resin adsorption includes a volume ratio of 1:3 to 1:10 between the sugar solution and the macroporous resin and a processing period of 4˜12 h; the processing condition for the activated carbon adsorption includes a volume ratio of 1:3 to 1:10 between the sugar solution and the activated carbon and a processing period of 4˜12 h. Among others, the macroporous resin can be selected from the group consisting of macroporous adsorption resin AB-8 with a weak polarity; activated carbon particles are in the size of 20-40 mesh; and iodine adsorption value: ≧1000.
[0055] In addition, for the purpose of more efficient and high-value utilization of straw, the solid material obtained in the method of the present invention can also be fed to the alkaline extraction tank; a 0.2%˜10% NaOH solution is added and kept at a temperature of 130° C. to 200° C. for 0.5 h˜4 h; solid-liquid separation is conducted to obtain an alkaline extraction residue and an alkaline extraction liquid; the extraction liquid passes through the an ultrafiltration membrane for collecting the solid material obtained by the ultrafiltration; the collected solid material is lignin with a high purity; the alkaline extraction residue is combed mechanically to separate long fibers and short fibers.
[0056] The lignin obtained in the above step can be used for the production of phenolic resin adhesive, a phenolic resin, a rubber reinforcing agent, and a nano-carbon fiber. The long fibers obtained in the above step can, after liquefaction, be used for the production of dissolving pulp, microcrystalline cellulose, and sodium hydroxymethyl cellulose. The short fibers obtained in the above step can, after liquefaction, be used for the production of polyether polyols. A sugar solution is obtained after bio-enzymolysis of the short fibers, and can be used in the production of a variety of fermentation products (see FIG. 1 for the specific process routes).
[0057] Accordingly, in another embodiment of the method of the present invention, the solid material obtained by the method of the present invention is processed into one or more of lignin, the long fibers and short fibers, wherein the lignin is further processed into industrial derivatives which is one or more selected from the group consisting of phenolic resin adhesive, a phenolic resin, a rubber reinforcing agent, and nano-carbon fiber; the long fibers and short fibers are further processed into sodium hydroxymethyl cellulose, polyether polyol and fermentation products. In a preferred embodiment, the fermentation products include butanol, succinic acid, butanediol, lactic acid, methane and hydrogen.
[0058] The method of the present invention is further explained in detail below in reference to the detailed Examples. It should be understood that the following Examples are only intended to illustrate the present invention, rather than to limit the scope of the present invention. In addition, unless otherwise specified, the raw materials and reagents used in the present invention are commercially available.
EXAMPLE 1
[0059] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Water at 15° C. was added to the straw pieces, and the straw pieces were soaked in the water for 60 min, wherein the mass ratio of straw to water was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 0.3 MPa for 10 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then fed into an acid-hydrolysis tank in a size of 80 m 3 , and hydrolyzed with 0.8 wt % sulfuric acid, wherein the mass ratio of the steam-exploded straw to the acid was 1:2, the hydrolysis temperature was 75° C. The reaction was performed for 60 mins. Then, the steam-exploded straw and hydrolyzate liquid from the hydrolysis tank were fed into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 75% (see Table 1).
EXAMPLE 2
[0060] This Example was carried out in a substantially same manner as in Example 1, except that the straw was soaked in water at 50° C. for 30 mins; the mass ratio of straw to water was 1:2; the processing conditions for the steam explosion included a 0.8 Mpa pressure for 5 minutes; acid treatment conditions included a 30 mins reaction between 1.2 wt % of sulfuric acid and the steam-exploded straw at 90° C., wherein the mass ratio of the steam-exploded straw to the acid was 1:5.
[0061] The steam-exploded straw and hydrolyzate liquid from the hydrolysis tank were fed into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 82% (see Table 1).
EXAMPLE 3
[0062] This Example was carried out in a substantially same manner as in Example 1, except that the straw was soaked in water at 90° C. for 10 mins; the mass ratio of straw to water was 1:3; the processing conditions for the steam explosion included a 2 Mpa pressure for 1 minutes; acid treatment conditions included a 10 mins reaction between 1.6 wt % of sulfuric acid and the steam-exploded straw at 105° C., wherein the mass ratio of the steam-exploded straw to the acid was 1:7.
[0063] The steam-exploded straw and hydrolyzate liquid from the hydrolysis tank were fed into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 90% (see Table 1).
COMPARATIVE EXAMPLE 1
[0064] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Water at 90° C. was added to the straw pieces, and the straw pieces were soaked in the water for 10 mins, wherein the mass ratio of straw to water was 1:3. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 2 MPa for 1 min to generate a steam-exploded wet straw material. The steam-exploded straw and hydrolyzate liquid from the hydrolysis tank were fed into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded straw reached 60% (see Table 1).
EXAMPLE 4
[0065] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Then 0.01 wt % of sulfuric acid was added to the straw pieces, and the straw pieces were soaked in the sulfuric acid for 10 mins, wherein the mass ratio of straw to acid was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 0.3 MPa for 0.5 min to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then added to and soaked in water in the weight equal to 4 times of that of the original straw material at 70° C. for 30 mins. Subsequently, the steam-exploded wet straw material was extruded using an extruder to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 60% (see Table 2).
EXAMPLE 5
[0066] This Example was carried out in a substantially same manner as in Example 4, except that the straw was soaked in 0.04 wt % of sulfuric acid for 30 mins; the mass ratio of straw to acid was 1:2; the condition for the steam explosion included obtaining of a steam-exploded wet straw material under a 0.6 Mpa pressure for 2 minutes; the conditions for the product collection included soaking the steam-exploded wet straw material in water in the weight equal to 7 times of that of the original straw material at 70° C. for 45 mins.
[0067] The steam-exploded wet straw material was extruded using an extruder to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 78% (see Table 2).
EXAMPLE 6
[0068] This Example was carried out in a substantially same manner as in Example 4, except that the straw was soaked in 0.1 wt % of sulfuric acid for 60 mins; the mass ratio of straw to acid was 1:3; the condition for the steam explosion included obtaining of a steam-exploded wet straw material under a 1.0 Mpa pressure for 3 minutes; the conditions for the product collection included soaking the steam-exploded wet straw material in water in the weight equal to 10 times of that of the original straw material at 70° C. for 10 mins.
[0069] The steam-exploded wet straw material was extruded using an extruder to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 85% (see Table 2).
COMPARATIVE EXAMPLE 2
[0070] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Then 0.1 wt % of sulfuric acid was added to the straw pieces, and the straw pieces were soaked in the sulfuric acid for 60 mins, wherein the mass ratio of straw to acid was 1:3. The wet straw material was then added to and soaked in water in the weight equal to 10 times of that of the original straw material at 70° C. for 10 mins. Subsequently, the wet straw material was extruded using an extruder to separate and obtain a straw hydrolyzate liquid and a straw solid material. The contents of cellulose, hemicellulose and lignin in the straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the acid-treated straw was 3% (see Table 2).
[0000]
TABLE 1
Degradation after water immersion, steam explosion treatment in combination with acid treatment
Pretreatment
Steam explosion
Mass ratio
treatment
Acid treatment
of straw
Steam-
Pressure
Acid
Mass ratio of
Degradation
Example
Soaking
to soaking
Soaking
explosion
maintenance
concentration
steam-exploded
Reaction
rate of
No.
solution
solution
condition
pressure
period
(wt %)
straw to acid
condition
hemicellulose
Ex. 1
water
1:1
15° C.,
0.3 MPa
10 min
0.8%
1:2
75° C.,
75%
60 min
sulfuric acid
60 min
Ex. 2
water
1:2
50° C.,
0.8 MPa
5 min
1.2%
1:5
90° C.,
82%
30 min
sulfuric acid
30 min
Ex. 3
water
1:3
90° C.,
2 MPa
1 min
1.6%
1:7
105° C.,
90%
10 min
sulfuric acid
10 min
Com.
water
1:3
90° C.,
2 MPa
1 min
—
—
—
60%
Ex. 1
10 min
[0000]
TABLE 2
Degradation after acid immersion in combination with steam explosion treatment
Pretreatment
Steam explosion
Product
Mass ratio
treatment
collection
Soaking
of straw
Steam-
Pressure
Mass ratio of
Degradation
Example
solution
to soaking
Soaking
explosion
maintenance
steam-exploded
Soaking
rate of
No.
(wt %)
solution
condition
pressure
period
straw to water
condition
hemicellulose
Ex. 4
0.01%
1:1
15° C.,
0.3 MPa
0.5 min
1:4
70° C.,
60%
sulfuric acid
10 min
30 min
Ex. 5
0.04%
1:2
15° C.,
0.6 MPa
2 min
1:7
70° C.,
78%
sulfuric acid
30 min
45 min
Ex. 6
0.1%
1:3
15° C.,
1.0 MPa
3 min
1:10
70° C.,
85%
sulfuric acid
60 min
10 min
Com.
0.1%
1:3
15° C.,
—
—
1:10
70° C.,
3%
Ex. 2
sulfuric acid
60 min
60 min
[0071] As seen in Table 1, the conditions for the pretreatment and steam explosion treatment of straw were the same in Comparative Example 1 and Example 3, but the steam-exploded straw was not subjected to an acid treatment in Comparative Example 1. In Comparative Example 1, the degradation rate of the hemicellulose in the steam-exploded straw reached 60%, whereas in Example 3, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 90%. From the comparison of the degradation rate of the hemicellulose in Examples 1˜3 and in Comparative Example 1, it was demonstrated that the degradation rate of the hemicellulose was higher after the straw was subjected to water immersion, steam explosion treatment in combination with acid treatment than to water immersion and steam explosion treatment only.
[0072] As seen in Table 2, the conditions for the pretreatment (i.e. acid soaking) of straw were the same in Example 6 and Comparative Example 2, but the acid-soaked straw was not subjected to a steam explosion treatment in Comparative Example 2. In Comparative Example 2, the degradation rate of the hemicellulose in the acid-soaked straw was 3%, whereas in Example 6, the degradation rate of the hemicellulose in the steam-exploded and acid-soaked straw reached 85%. From the comparison of the degradation rate of the hemicellulose in Examples 4˜6 and in Comparative Example 2, it was demonstrated that the degradation rate of the hemicellulose was higher after the straw was subjected to acid soaking in combination with steam explosion treatment than to acid soaking only.
EXAMPLE 7
[0073] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Water at 15° C. was added to the straw pieces, and the straw pieces were soaked in the water for 60 mins, wherein the mass ratio of straw to water was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 0.8 MPa for 4 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then fed into an acid-hydrolysis tank in a size of 80 m 3 , and hydrolyzed with 1.6 wt % hydrochloric acid, wherein the mass ratio of the steam-exploded straw to the acid was 1:2, the hydrolysis temperature was 105° C. After 60 mins reaction, the steam-exploded straw and hydrolyzate liquid were fed from the acid-hydrolysis tank into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 85%.
EXAMPLE 8
[0074] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Then 0.1 wt % of hydrochloric acid was added to the straw pieces, and the straw pieces were soaked in the sulfuric acid for 30 mins, wherein the mass ratio of straw to acid was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 1.0 MPa for 3 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then added to and soaked in water in the weight equal to 10 times of that of the original straw material at 70° C. for 30 mins. Subsequently, the steam-exploded wet straw material was extruded using an extruder to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 75%.
EXAMPLE 9
[0075] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Water at 15° C. was added to the straw pieces, and the straw pieces were soaked in the water for 60 mins, wherein the mass ratio of straw to water was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 0.8 MPa for 4 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then fed into an acid-hydrolysis tank in a size of 80 m 3 , and hydrolyzed with 1.6 wt % phosphoric acid, wherein the mass ratio of the steam-exploded straw to the acid was 1:2, the hydrolysis temperature was 105° C. After 20 mins reaction, the steam-exploded straw and hydrolyzate liquid were fed from the acid-hydrolysis tank into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 82%.
EXAMPLE 10
[0076] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Then 0.1 wt % of phosphoric acid was added to the straw pieces, and the straw pieces were soaked in the phosphoric acid for 30 mins, wherein the mass ratio of straw to acid was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 1.0 MPa for 3 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then added to and soaked in water in the weight equal to 10 times of that of the original straw material at 70° C. for 30 mins. Subsequently, the steam-exploded wet straw material was extruded using an extruder to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 69%.
EXAMPLE 11
[0077] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Water at 15° C. was added to the straw pieces, and the straw pieces were soaked in the water for 60 mins, wherein the mass ratio of straw to water was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 1.3 MPa for 4 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then fed into an acid-hydrolysis tank in a size of 80 m 3 , and hydrolyzed with 1.0 wt % nitric acid, wherein the mass ratio of the steam-exploded straw to the acid was 1:2, the hydrolysis temperature was 105° C. After 60 mins reaction, the steam-exploded straw and hydrolyzate liquid were fed from the acid-hydrolysis tank into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 85%.
EXAMPLE 12
[0078] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Then 0.1 wt % of nitric acid was added to the straw pieces, and the straw pieces were soaked in the sulfuric acid for 30 mins, wherein the mass ratio of straw to acid was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 1.0 MPa for 3 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then added to and soaked in water in the weight equal to 10 times of that of the original straw material at 70° C. for 30 mins. Subsequently, the steam-exploded wet straw material was extruded using an extruder to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 72%.
EXAMPLE 13
[0079] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Water at 15° C. was added to the straw pieces, and the straw pieces were soaked in the water for 60 mins, wherein the mass ratio of straw to water was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 1.3 MPa for 4 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then fed into an acid-hydrolysis tank in a size of 80 m 3 , and hydrolyzed with a 1.0 wt % acid mixture (the mass ratio of sulfuric acid to phosphoric acid was 4:3 in the acid mixture), wherein the mass ratio of the steam-exploded straw to the acid was 1:2, the hydrolysis temperature was 105° C. After 60 mins reaction, the steam-exploded straw and hydrolyzate liquid were fed from the acid-hydrolysis tank into a plate filter to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 85%.
EXAMPLE 14
[0080] One ton of air-dried corn straw (its water content is less than 5 wt %) was cut into 5-10 cm pieces by a cutting machine. Then a 0.1 wt % acid mixture (the mass ratio of sulfuric acid to hydrochloric acid was 1:1 in the acid mixture) was added to the straw pieces, and the straw pieces were soaked in the acid for 30 mins, wherein the mass ratio of straw to acid was 1:1. Then the wet straw material was fed into a steam-explosion tank in a size of 11 m 3 , and processed at a pressure of 1.0 MPa for 3 mins to generate a steam-exploded wet straw material. The steam-exploded wet straw material was then added to and soaked in water in the weight equal to 10 times of that of the original straw material at 70° C. for 30 mins. Subsequently, the steam-exploded wet straw material was extruded using an extruder to separate and obtain a steam-exploded straw hydrolyzate liquid and a steam-exploded straw solid material. The contents of cellulose, hemicellulose and lignin in the steam-exploded straw solid material were measured. Compared with the chemical composition of the original straw, the degradation rate of the hemicellulose in the steam-exploded and acid-treated straw reached 72%.
EXAMPLE 15
[0081] The purpose of this Example is to demonstrate use of the hydrolyzate liquid obtained after the degradation of straw for butanol fermentation, wherein the straw was processed in the same manner as in Example 2.
[0082] The steam-exploded straw hydrolyzate liquid separated and obtained through the plate filter was distilled under a reduced pressure of 0.9 MPa and at 70° C. The distillate was collected and rectified. Then 1.1 kg of furfural and 3.3 kg of acetic acid were obtained.
[0083] The sugar solution that was distilled under a reduced pressure first passed through an electrodialysis device to separate acid radical ions therein, wherein the separation conditions included a temperature of 15° C. and a current density of 600 A/m 2 . Then, the sugar solution passed through macroporous resin (AB-8, The Chemical Plant of Nankai University, Tianjin) to remove pigment in the sugar solution, wherein the separation conditions included a volume ratio of 1:5 between the sugar solution and the resin and a processing period of 12 hours. Finally, soluble lignin was removed from the sugar solution using activated carbon, wherein the separation conditions included a volume ratio of 1:5 between the sugar solution and the activated carbon (GH-6, Guanghua Jingke Activated Carbon Co., Ltd.) and a processing period of 12 hours. The sugar solution processed as above was used as the carbon source, wherein the concentration of sugar (glucose and xylose) was 50 g/L. Ammonium acetate was used as the nitrogen source. Then trace elements were added to prepare the fermentation medium. The proportion of the carbon source to nutrients was 1:10. The fermentation medium was adjusted to pH6.5 using NaOH, and sterilized at 121° C. for 10 mins.
[0084] C. acetobutylicum ATCC824 was inoculated into 7% (v/v) corn medium, cultured at 37° C. in an anaerobic condition for 24 hours, and after complete floating of the mash cover, transferred to the fermentation medium. The inoculation solution and the fermentation broth are in a volume ratio of 1:10. After the anaerobic culture at 37° C. for 72 hours, fermentation mash having a total solvent content of 22 g/L was obtained in the fermentation broth, wherein the concentration of butanol was 15 g/L.
EXAMPLE 16
[0085] The purpose of this Example is to demonstrate use of the hydrolyzate liquid obtained after the degradation of straw for butanol fermentation, wherein the straw was processed in the same manner as in Example 5.
[0086] The steam-exploded straw hydrolyzate liquid separated and obtained through the extruder was distilled under a reduced pressure of 0.9 MPa and at 70° C. The distillate was collected and rectified. Then 2.1 kg of furfural and 5.2 kg of acetic acid were obtained.
[0087] The sugar solution that was distilled under a reduced pressure first passed through an electrodialysis device to separate acid radical ions therein, wherein the separation conditions included a temperature of 15° C. and a current density of 1000 A/m 2 . Then, the sugar solution passed through macroporous adsorption resin (S-8, Anhui Sanxing Resin Technology Co., Ltd.,) to remove pigment in the sugar solution, wherein the separation conditions included a volume ratio of 1:7 between the sugar solution and the resin and a processing period of 8 hours. Finally, soluble lignin was removed from the sugar solution using activated carbon, wherein the separation conditions included a volume ratio of 1:10 between the sugar solution and the activated carbon (GH-6, Guanghua Jingke Activated Carbon Co., Ltd.) and a processing period of 12 hours. The sugar solution processed as above was used as the carbon source, wherein the concentration of sugar (glucose and xylose) was 80 g/L. Peptone was used as the nitrogen source. Then trace elements were added to prepare the fermentation medium. The proportion of the carbon source to nutrients was 1:8. The fermentation medium was adjusted to pH6.5 using NaOH, and sterilized at 121° C. for 10 mins.
[0088] The seed medium for Klebsiella sp. LN145 contained yeast extract 2.0 g/L, peptone 5.0 g/L, NaCl 5.0 g/L, malt extract 1.5 g/L, and glucose 20 g/L. Klebsiella sp. LN145 in the logarithmic growth phase was inoculated into the fermentation medium, wherein the inoculation amount was 10% (v/v). After an aerobic culture at 30° C. for 96 hours, the concentration of 2,3-butanediol was 34.4 g/L in the fermentation broth.
EXAMPLE 17
[0089] The purpose of this Example is to demonstrate use of the hydrolyzate liquid obtained after the degradation of straw for butanol fermentation, wherein the straw was processed in the same manner as in Example 3.
[0090] The steam-exploded straw hydrolyzate liquid separated and obtained through the plate filter was distilled under a reduced pressure of 0.9 MPa and at 70° C. The distillate was collected and rectified. Then 1.5 kg of furfural and 3.9 kg of acetic acid were obtained.
[0091] The sugar solution that was distilled under a reduced pressure first passed through an electrodialysis device to separate acid radical ions therein, wherein the separation conditions included a temperature of 30° C. and a current density of 800 A/m 2 . Then, the sugar solution passed through macroporous adsorption resin (Amberlite XAD-4, USA) to remove pigment in the sugar solution, wherein the separation conditions included a volume ratio of 1:7 between the sugar solution and the resin and a processing period of 8 hours. Finally, soluble lignin was removed from the sugar solution using activated carbon(GH-6, Guanghua Jingke Activated Carbon Co., Ltd.), wherein the separation conditions included a volume ratio of 1:10 between the sugar solution and the activated carbon and a processing period of 12 hours. The straw hemicellulose degradation liquid obtained from the above processing was used as the carbon source, wherein the concentration of sugar (glucose and xylose) was 100 g/L. Peptone was used as the nitrogen source. Then trace elements were added to prepare the fermentation medium. The proportion of the carbon source to nutrients was 1:8. The fermentation medium was adjusted to pH6.5 using NaOH, and sterilized at 121° C. for 10 mins.
[0092] The seed medium for Lactobacillus sp ZJU-1 contained 10 ml of malt juice (10° Brix) and 1 g of CaCO 3 , and was sterilized at 115° C. for 20 mins. Lactobacillus sp ZJU-1 in the logarithmic growth phase was inoculated into the fermentation medium, wherein the inoculation amount was 10% (v/v). After an aerobic culture at 30° C. for 96 hours, the concentration of lactic acid was 88 g/L in the fermentation broth.
EXAMPLE 18
[0093] The purpose of this Example is to demonstrate use of the hydrolyzate liquid obtained after the degradation of straw for butanol fermentation, wherein the straw was processed in the same manner as in Example 6.
[0094] The steam-exploded straw hydrolyzate liquid separated and obtained through the plate filter was distilled under a reduced pressure of 0.9 MPa and at 70° C. The distillate was collected and rectified. Then 2.5 kg of furfural and 5.3 kg of acetic acid were obtained.
[0095] The sugar solution that was distilled under a reduced pressure first passed through an electrodialysis device to separate acid radical ions therein, wherein the separation conditions included a temperature of 30° C. and a current density of 1000 A/m 2 . Then, the sugar solution passed through macroporous adsorption resin (Amberlite XAD-6, USA) to remove pigment in the sugar solution, wherein the separation conditions included a volume ratio of 1:3 between the sugar solution and the resin and a processing period of 8 hours. Finally, soluble lignin was removed from the sugar solution using activated carbon(GH-6, Guanghua Jingke Activated Carbon Co., Ltd.), wherein the separation conditions included a volume ratio of 1:3 between the sugar solution and the activated carbon and a processing period of 12 hours. The sugar solution processed as above was used as the carbon source, wherein the concentration of sugar (glucose and xylose) was 20 g/L. Peptone was used as the nitrogen source. Then trace elements were added to prepare the fermentation medium. The proportion of the carbon source to nutrients was 1:8. The fermentation medium was adjusted to pH6.5 using NaOH, and sterilized at 121° C. for 10 mins.
[0096] Activated sludge was obtained from the Gaobeidian Sewage Plant, Beijing. The activated sludge was added directly to the fermentation medium, and the inoculation amount was 10% (v/v). The anaerobic fermentation was carried out for 10 d. One liter of methane was collected from each liter of the fermentation medium.
EXAMPLE 19
[0097] The purpose of this Example is to demonstrate use of the hydrolyzate liquid obtained after the degradation of straw for butanol fermentation, wherein the straw was processed in the same manner as in Example 1.
[0098] The steam-exploded straw hydrolyzate liquid separated and obtained through the plate filter was distilled under a reduced pressure of 0.9 MPa and at 70° C. The distillate was collected and rectified. Then 1.1 kg of furfural and 3.3 kg of acetic acid were obtained.
[0099] The sugar solution that was distilled under a reduced pressure first passed through an electrodialysis device to separate acid radical ions therein, wherein the separation conditions included a temperature of 15° C. and a current density of 600 A/m 2 . Then, the sugar solution passed through anion exchange resin (HZ-803, Huazhen Technology Company, Shanghai) to remove salt ions in the sugar solution, wherein the separation conditions included a volume ratio of 1:10 between the sugar solution and the resin and a processing period of 12 hours. Finally, soluble lignin was removed from the sugar solution using activated carbon (GH-6, Guanghua Jingke Activated Carbon Co., Ltd.), wherein the separation conditions included a volume ratio of 1:10 between the sugar solution and the activated carbon and a processing period of 12 hours. The straw hemicellulose degradation liquid obtained from the above processing was used as the carbon source, wherein the concentration of sugar (glucose and xylose) was 40 g/L. Ammonium acetate was used as the nitrogen source. Then trace elements were added to prepare the fermentation medium. The proportion of the carbon source to nutrients was 1:8. The fermentation medium was adjusted to pH6.5 using NaOH, and sterilized at 121° C. for 10 mins.
[0100] The seed medium for Clostridium butyrium AS 1.209 contained glucose 20 g/L, yeast extract 0.5 g/L, KH 2 PO 4 0.2 g/L, K 2 HPO 4 1.6 g/L, MgSO 4 .7H 2 O 0.2 g/L, NaCl 0.1 g/L, CaCl 2 0.01 g/L, Na 2 S.9H 2 O 0.25 g/L, NaMoO 4 .2H 2 O 0.01 g/L, NaHCO 3 0.2 g/L and (NH 4 ) 2 SO 4 3.0 g/L, and was sterilized at 115° C. for 15 mins. Clostridium butyrium AS1.209 in the logarithmic growth phase was inoculated into the fermentation medium, wherein the inoculation amount was 10% (v/v). After an anaerobic culture at 37° C. for 60 hours, 0.5L of hydrogen was collected from each liter of the fermentation medium.
EXAMPLE 20
[0101] The purpose of this Example is to demonstrate use of the solid material obtained after the degradation of straw for the production of industrial derivatives, wherein the straw was processed in the same manner as in Example 1.
[0102] The solid material obtained by squeezing the steam exploded straw was fed to an alkaline extraction tank. A 2 wt % NaOH solution was added and kept at a temperature of 150° C. for 4 hours. The solid material was extruded by an extruder, so as to obtain an alkaline extraction liquid and an alkaline extraction residue; the extraction liquid passed through a PVC ultrafiltration membrane to recover NaOH. The solid material obtained by the ultrafiltration was collected and dried to obtain lignin. The lignin was used for the production of phenolic resin adhesive, phenolic resin, rubber reinforcing agent, nano-carbon fiber. The alkaline extraction residue passed through a mechanical carding machine to separate long fibers and short fibers, wherein the long fibers were used for the production of sodium hydroxymethyl cellulose and polyether polyols and the short fibers were degraded into glucose while cellulase was added.
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Provided is a process for producing biomass-based product from straw hemicellulose and utilizing the components thereof thoroughly. Steam-explosion and acid-hydrolysis are combined in the pre-treatment of straw in the process, thus a higher concentration of a sugar liquid can be obtained, and furfural and acetic acid can be recovered. The hemicellulose obtained by the pre-treatment can be used directly as ferment materials for producing butanol, succinic acid, butylene glycol, lactic acid, hydrogen and firedamp, which reduces the cost of these biomass-based products. The cellulose and lignin obtained by extracting the straw with an alkaline solution can produce products, such as sodium hydroxymethyl cellulose etc. In the process, all components in the straw can be utilized thoroughly and waste and pollutant will not be produced.
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BACKGROUND
The field of the invention is infusion pumps and relates generally to systems, apparatuses, and methods for pumping or infusing volumes of medical fluids to a patient, typically via an intravenous route.
Infusion pumps are used to infuse drugs and liquids into patients, typically via intravenous lines. While some infusion pumps deal with relatively large volumes, there may be more interest in pumps with a capability of delivering only very small controlled volumes of liquid. The drugs used may be very important, such as analgesics, anesthetics including opiates, anti-inflammatory agents, insulin, anti-spasmodic drugs, antibiotics, chemotherapy agents, cardiovascular drugs, and the like. Many of these drugs are needed in very low doses on a continuous basis, so that the patient has a steady, reliable stream over a long period of time, such as 0.1 ml per hour. If pulses are used, the dosage rate may be measured in terms of nanoliters or microliters per pulse or bolus. Patients thus depend on infusion pumps for reliable, consistent delivery of very small volumes.
Some infusion pumps propel or pump the liquid of interest by admitting a quantity of liquid into a length of tubing and isolating that quantity, as by occluding a valve at an inlet of the tubing. A mechanism then opens a valve at an outlet of the tubing and another mechanism compresses or otherwise massages the length of tubing in question. Since the inlet is blocked by the closed valve, the liquid can only exit through the outlet, with an open valve. This method works. However, there are at least two drawbacks to this method. Present day infusion pumps, using this type of shuttle mechanism, may squeeze the length of tubing by pressing a moving shuttle against a stationary block.
In cross-section, the tube resides in a diamond-shaped groove or pumping chamber formed by the opposed shuttle and block. Typically, the profiles of the shuttle and the block, or stationary portion, are not very well suited for maintaining the tube in an ideal position throughout the entire compression cycle. Because of this, the profile of the shuttle and block do not always achieve full compression of the tube at any given point during the pumping cycle. For example, prior art infusion pumps operate by occluding tubing between a moving shuttle and a stationary block. The tubing is not completely occluded because prior art pumps do not entirely compress the tubing, leaving the ends of the tubing non-occluded. This situation has at least two disadvantages: an unpredictable amount of liquid remains in the tubing, negatively affecting pump accuracy, and full pumping capacity is not utilized. Over-squeezing the tubing to complete the occlusion can adversely affect tubing life, while under-squeezing lessens the pumping capacity and may adversely affect pumping volume control accuracy.
Typically, the inlet valve, shuttle, and outlet valves previously mentioned are operated via a single motor or actuator. The timing of the operation of each is accomplished by a mechanical linkage. Accordingly, each stroke of the shuttle mechanism pumps a fixed amount of fluid. Therefore, it is difficult or impossible to adjust the pumping capacity or other pumping characteristic of the pump.
SUMMARY
An improved infusion pump is provided in several embodiments.
One embodiment is an infusion pump. The infusion pump includes an inlet valve, an outlet valve, and a shuttle including a shuttle stationary portion and a shuttle moveable portion configured for squeezing a length of tubing between the shuttle stationary portion and the shuttle movable portion, wherein the shuttle moveable portion moves toward and away from the shuttle stationary portion to operate the infusion pump, wherein the shuttle stationary portion and the shuttle moveable portion each include a symmetrical groove for holding and squeezing the length of tubing, the groove symmetrical about a central axis of the groove.
Another embodiment is an infusion pump. The infusion pump includes a housing and contained within the housing, an inlet valve, an outlet valve, and a shuttle including a shuttle stationary portion and a shuttle moveable portion configured for squeezing a length of tubing between the shuttle stationary portion and the shuttle movable portion, wherein the shuttle moveable portion moves toward and away from the shuttle stationary portion to squeeze the tubing, wherein the shuttle stationary portion and the shuttle moveable portion each include a base with a symmetric channel for containing the tubing, each of the shuttle stationary portion and the shuttle movable portion including a plurality of transverse ridges and transverse recesses rising from the base and the channel, wherein a height of the ridges above the channel is less than an outer diameter of the tubing.
Another embodiment is a method of pumping an infusate. The method includes the steps of furnishing an infusion pump, the infusion pump including at least one shuttle having a shuttle stationary portion and a shuttle moving portion, wherein the shuttle stationary portion and the shuttle moveable portion each include a base with a symmetric channel and a plurality of ridges and recesses rising from the base and the channel, wherein the ridges on both sides of the channel are symmetrical. The method also includes controlling operation of the infusion pump by entering commands through at least one input to a controller of the pump, pumping infusate by periodically moving the shuttle moveable portion with respect to the shuttle stationary portion, whereby substantially all of an outer circumference of the tubing is in contact with the portions of the shuttle stationary portion and the shuttle moving portion, and sequentially opening and closing at least one valve of the infusion pump to admit the infusate and to allow the infusion pump to pump the infusate.
Another embodiment is a linear shuttle peristaltic pump. The linear shuttle peristaltic pump includes at least one stationary section, the at least one stationary section including a base, a symmetric channel, at least one ridge on a first side of the channel and at least one recess on a second side of the channel, wherein the channel is formed with symmetrical angles on each side of a center of the channel. The pump also includes a plurality of moveable sections, each moveable section including a base, a symmetric channel, a ridge on a first side of the channel and a recess on a second side of the channel, wherein the channel is formed with symmetrical angles on each side of a center of the channel, and wherein the at least one ridge and at least one recess in the at least one stationary section fit into the recesses and ridges of the moveable sections, and wherein when the at least one stationary section and the plurality of movable sections are assembled, the channels form an opening suitable for a length of tubing, whereby substantially all of an outer circumference of the tubing is in contact with portions of the at least one stationary section and portions of the moving sections when the moving sections operate to squeeze the length of tubing, and a plurality of linear actuators connected to the plurality of moveable sections, each of the plurality of linear actuators further including a sensor for reporting a position of the actuator. In another embodiment, the linear actuators are replaced with a single motor and a cam in contact with each of the plurality of moveable sections.
Another embodiment is a method of pumping a liquid. The method includes the steps of providing a linear shuttle peristaltic pump, the pump including a plurality of shuttle stationary sections and a plurality of shuttle moving sections, each of the sections having a symmetric groove with at least one transverse ridge and at least one transverse recess, wherein the ridges and the recesses of the stationary sections fit into matching recesses and ridges of the moving sections, and wherein substantially all of an outer circumference of tubing in the pump is in contact with surfaces of the stationary sections and the moving sections when the tubing is squeezed. The method also includes controlling operation of the linear shuttle peristaltic pump by entering commands through at least one input to a controller of the pump, pumping liquid by sequentially moving the shuttle moveable sections with respect to the shuttle stationary sections, and sequentially opening and closing at least one valve of the infusion pump to admit the infusate and to allow the infusion pump to pump the infusate.
Another embodiment is a geometry-controlled valve. The valve includes a stationary section, the stationary section including a base, a symmetric channel, at least one ridge on a first side of the channel and at least one recess on a second side of the channel, wherein the channel is formed with symmetrical angles on each side of a center of the channel, and a moveable section, the moveable section including a base, a symmetric channel, a ridge on a first side of the channel and a recess on a second side of the channel, wherein the channel is formed with symmetrical angles on each side of a center of the channel, and wherein the at least one ridge and at least one recess in the stationary section fit into the recesses and ridges of the moveable section, and wherein when the stationary section and the movable section are assembled, the channels form an opening suitable for a length of tubing, whereby substantially all of an outer circumference of the tubing is in contact with the portions of the stationary section and the moving section when the moving section operates to squeeze the length of tubing.
Additional features and advantages are described herein, and will be apparent from, the following Detailed Description and the Figures.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic view of an infusion pump controller with two infusion modules;
FIG. 2 is a partial cross-section of a prior-art infusion pump geometry;
FIG. 3 is a partial cross-section of a profile view of a new infusion pump shuttle geometry;
FIGS. 4A and 4B are perspective views of an improved shuttle pump geometry;
FIGS. 5A and 5B are partial cross-sectional views depicting filling and pumping phases of a shuttle pump with the improved geometry;
FIG. 6 is a perspective view of another shuttle design;
FIG. 7 is a perspective view of another shuttle geometry design;
FIG. 8 is a perspective view of yet another shuttle geometry design;
FIG. 9 is a perspective view of another application of the improved shuttle design;
FIG. 10 is a perspective view of an embodiment of a moving shuttle section;
FIG. 11 depicts another embodiment of a shuttle-type infusion pump;
FIG. 12 depicts yet another embodiment of a shuttle-type infusion pump;
FIGS. 13A and 13B depict infusion pumping by the embodiment of FIG. 6 ; and
FIG. 14 depicts an application wherein a single controller is used to control and monitor a plurality of infusion pumps for a patient.
DETAILED DESCRIPTION
One embodiment is depicted in FIG. 1 . Infusion pump system 10 includes a housing 12 for the infusion pump microcontroller 28 , and also includes first infusion pump 14 and second infusion pump 16 , a video output 18 and an audio output or speaker 20 . The video output 18 is a screen, which may be a touch-screen, allowing for inputs to the microcontroller 28 . The infusion pump system 10 also includes inputs 26 , which may be conveniently located near screen 18 . The infusion pump system 10 includes additional inputs/outputs (I/O), including a landline 22 suitable for cable or other I/O, such as an intranet or cable for a home, a hospital or other care center. There is also an antenna 24 for wireless communication to and from a central monitoring station or other controller (not shown). The infusion pump system 10 includes a battery 25 and may also receive power from an external source via a power cord 27 .
The first infusion pump 14 receives liquid from a first container 34 and the second infusion pump 16 receives liquid from a second container 36 . The flow of liquid is then conveyed to the respective infusion pump via tubing 348 , 366 . The tubing 348 , 366 in this embodiment is continuous before and after the infusion pumps 14 , 16 and extends to an access device connector 368 for each line. The access device connector 368 may be a vascular access device and may be used for administering a drug or other medicament to the patient.
The system controller is a microcontroller 28 , which includes a central processing unit (CPU), input/output capability (I/O), digital to analog converter (D/A), and random access memory (RAM) and read-only memory (ROM), and may include additional memory (MEM). A computer program for operating one or more infusion pumps 14 , 16 is stored in MEM or ROM. Microcontroller 28 receives inputs from the drip counters 342 , to monitor the input to the infusion pumps. The microcontroller 28 also receives inputs from a number of sensors or devices associated with the infusion pumps 14 , 16 , such as encoder data from rotary encoders on a motor driving the infusion pump, linear voltage displacement transducer (LVDT) data or other position or displacement data from linear actuators, voltage or current readings from temperature or pressure sensors in the infusion pumps 14 , 16 , and the like. The data may be sent via wire harnesses 322 , 324 , 326 , or may be wireless, such as wireless signals conforming to the ZigBee/IEEE 805.15.4 wireless standard. The data may be received by the microcontroller 28 or the microcontroller 28 may include a separate interface for sensor circuits 32 , as shown. The infusion pumps 14 , 16 in this embodiment have a separate section for driver circuits 30 , for driving or controlling linear actuators, rotary actuators, motors, and the like.
Infusion pump 14 is driven by a motor 148 driving an infusion pump moveable shuttle section 144 by a camming drive train 146 . The moveable shuttle section 144 squeezes tubing 348 against the shuttle stationary section 142 to pump the liquid from container 34 . Upper valve 140 opens to admit liquid into the tubing 348 and closes when the tubing 348 is full. Lower valve 141 then opens just before the controller 28 commands infusion pump 14 to actuate and cycle the moveable shuttle section 144 . With upper valve 140 closed and lower valve 141 open, the liquid is forced through the lower valve and downstream through connector 368 . An encoder or other feedback device on motor 148 informs controller 28 of the position of the motor 148 , and thus the position of the moveable shuttle section 144 , and also allows calculation of volume pumped by the infusion pump 14 by the computer program.
The second infusion pump 16 operates with linear actuators. A linear actuator is a device that develops force and motion, from an available energy source, in a linear manner, as opposed to a device that operates in a rotary manner, as one that receives torque directly from a rotary electric motor. Examples of linear actuators include electric linear solenoids, linear pneumatic actuators, and hydraulic cylinders. Other examples include ball screws and jack screws, and also cylinders actuated by a linear motor. Infusion pumps as described herein place a premium on space and on reliability. While many types of linear actuators may be used, lead screws and stepper motors from and Haydon Switch & Instrument (HSI) of Waterbury, Conn., U.S.A. and from Portescap, West Chester, Pa., U.S.A., have been found useful for the present infusion pump application.
Infusion pump 16 includes a stationary portion 162 and two moveable shuttles 164 , 166 , as well as three valves 160 , 165 , and 170 , and five linear actuators 168 . The commands to the linear actuators 168 and their positions are reported via harness 326 to the driver circuit portion 30 and are also reported to the microcontroller 28 . Infusion pump 16 receives liquid from container 36 and drip chamber 346 and pumps via tubing 366 . In this embodiment, tubing 366 is a continuous piece of tubing 366 from the drip chamber 346 to connector 368 . Valve 165 closes and valve 160 opens to admit liquid into the tubing 366 downstream from valve 160 . When this portion of the tubing 366 is full, valve 160 closes, valve 165 opens, and shuttle 164 advances, pumping liquid downstream through valve 165 . Shuttle 166 is open to receive the liquid and valve 170 is closed. Then valve 165 closes, valve 170 is opened, and shuttle 166 closes, pumping the liquid downstream to connector 368 and to the patient. While shuttle 166 is closing, shuttle 164 retracts and valve 160 opens, admitting liquid upstream from valve 165 . The process is then repeated, with sequential advance and retraction of the shuttles and appropriate opening and closing of the valves.
The use of two shuttles smoothes the pumping process, so that part of the tubing is being pumped (emptied) while the remainder is being filled. When the first shuttle 164 pumps, the contents of the upper portion of the tubing 366 are discharged into the lower portion of the tubing 366 adjacent the second shuttle 166 . When the second shuttle 166 is pumping liquid to the patient, the tubing adjacent the first shuttle 164 is being re-filled. The tubing is quickly filled because the liquid has only to traverse the tubing immediately adjacent the first shuttle 164 . Using this technique, a smooth, virtually continuous flow is achieved. In this embodiment, intermediate valve 165 acts as both the outlet valve for upper shuttle 164 and as input valve for lower shuttle 166 .
Prior art infusion pumps, such as the one shown in cross-section in FIG. 2 , do not uniformly squeeze the tubing 4 . Instead, an upper shuttle 6 and a lower stationary portion 7 may tend to compress the tubing so that a small amount of liquid may be left in the tubing, as seen in FIG. 2 , thus contributing to inaccuracy in the operation of the infusion pump. In one embodiment of the infusion pump disclosed herein, shown in FIG. 3 , the infusion pump has a central groove 8 that is symmetrical with respect to a center line L of the groove, with equal angles A on both sides 9 of the groove 8 . In one embodiment, the corner so formed has a gentle radius from about 0.020 inches to about 0.060 inches (about 0.50 mm to about 1.5 mm). A first embodiment of an improved shuttle pump made of a stationary block 40 and a moving shuttle 42 is depicted in FIGS. 4A and 4B .
The block 40 and the shuttle 42 are each made of a base with a plurality of alternating ridges 46 and recesses 48 , with a central channel 44 . The ridges 46 of one portion fit into the recesses 48 of the other, allowing sliding movement of the moving shuttle 42 with respect to the stationary block 40 . The central channel 44 is configured for receiving a length of tubing, and should have a generous radius and be free from nicks and burrs. The ridges 46 rise perpendicularly from the base at the top and bottom edges of block 40 and shuttle 42 , but form an angle B to the central channel of about 45 degrees. In this embodiment, the angles B and the channel are symmetrical with respect to a horizontal plane H bisecting the central channel, i.e., angles B are equal. The sum of the two angles B is from about 60 degrees to about 120 degrees. The tubing will be held or contained in a symmetrical manner, helping to insure that the tubing is not distorted when pumping takes place.
FIGS. 5A and 5B depict a cross-section of the joined stationary and moving portions. In FIG. 5A , the stationary block 40 and moving shuttle 42 are aligned, exerting slight pressure on tubing 38 , which is contained within the area as shown between the block 40 and the shuttle 42 , with only sufficient pressure to deform normally round tubing 38 into the slightly compressed state shown. FIG. 5A depicts ridges 424 from shuttle 42 , which fit into recesses (not shown) of the block 40 . Tubing 38 rests in the open area and is symmetrical with respect to the horizontal plane H. Vertical plane V is perpendicular to the horizontal plane and is taken at the locus of the corner or central channel 44 . As seen in FIG. 5A , about three-fourths of the diameter of tubing 38 is contained within the block 40 , while about one-fourth extends about the top (right) surface of shuttle 42 .
As seen in FIG. 5B , the left and right portions, block 40 and shuttle 42 , match and overlap, and about three-fourths of the diameter of tubing 38 is also contained within the open area of shuttle 42 . The radius of the corner or central channel 44 in one embodiment is about 0.030 inches (about 0.75 mm). Base 402 of block 40 is the portion to the left of the vertical plane V. The base 404 of the shuttle 42 is similarly defined, but is to the right to of a vertical plane taken from the locus of its central channel. Block 40 has ridges 414 extending from its base 402 , while shuttle 42 has ridges 424 extending from its base 404 . In FIG. 5B , shuttle 42 has moved downward to squeeze the tubing 38 and pump the liquid infusate within the tubing 38 to the patient. Tubing 38 is deformed within the space, but with this geometry, the entire outer circumference or periphery of the tubing 38 , adjacent to ridges 414 , 424 is constrained between the matching ridges 414 of the block 40 and ridges 424 of the shuttle 42 .
Another embodiment of a block 410 and a shuttle 420 are shown in FIG. 6 . The block 410 and shuttle 420 are configured to accommodate and squeeze tubing 38 between them. In this embodiment, fingers 406 , 408 are added on both the block 410 and the shuttle 420 to help secure and squeeze the tubing 38 . In block 410 , rear fingers 406 and front fingers 408 are positioned adjacent the tubing 38 to fit into matching slots 48 in shuttle 420 . The fingers 406 , 408 push against the tubing 38 and help to contain and squeeze the tubing 38 when the shuttle 420 contacts the tubing 38 by squeezing it against block 410 . In this depiction, shuttle 420 has rotated downward and away from contact with the tubing 38 and fingers 406 , 408 in the block 410 are shown in contact with tubing 38 . Shuttle 420 also has rear fingers 406 (not shown), and front fingers 408 for performing the same function, containing and squeezing the tubing 38 , on the other side of the tubing. The fingers 406 , 408 on shuttle 420 fit into matching slots or recesses 48 on block 410 .
The block 410 and shuttle 420 described above may also be made and used in smaller portions for occluding the tubing 38 . For example, instead of squeezing a longer portion of the tubing 38 for pumping, a much shorter version may be used as a valve. FIGS. 7 and 8 depict an example. In FIG. 7 , occluder 70 may be used as the stationary portion or block, or alternatively may be used as the moving portion or shuttle, of a valve to occlude tubing. Occluder 70 is similar to the stationary and moving portions described above. Occluder 70 includes a base portion 72 , a central channel 74 , a single ridge 76 and a single recess 78 . The occluder 70 shown is used with a matching occluder 70 atop occluder 70 , with the ridge 76 of one occluder 70 placed into the recess 78 of the other, and vice versa. By sliding or maneuvering one occluder 70 back and forth, a length of tubing may be opened and closed, thus allowing and ceasing flow of liquid in an infusion pump. This configuration has the same advantages as the shuttle pumps discussed above, in that the entire circumference or periphery of the tubing is occluded and is less likely to be subjected to excessive pressures, leading to premature failure.
Another embodiment of an occluder that is capable of acting as a valve is depicted in FIG. 8 . In this embodiment, occluder 80 with base portion 82 includes two ridges 86 and two recesses 88 , a ridge 86 and a recess 88 on each side, the positions of the two reversed across the transverse central channel 84 . The embodiment is intended for use with two occluders 80 , one stationary and one moving, as with occluders 70 , block 40 and shuttle 42 . In addition, since both occluder embodiments 70 , 80 may also be used to push liquid from the tubing, they may be used to pump the liquid.
FIG. 9 depicts an embodiment in which a plurality of occluder sections 70 are used for both the stationary and moving portions of a linear peristaltic pump 60 . In the figure, several stationary sections 70 a are placed adjacent each other, their recesses 78 visible and accommodating ridges 76 from a matching number of identical moving portions 70 b placed atop the stationary sections 70 a . The moving portions 70 b are portrayed as staggered, as would be the sections of a linear peristaltic pump 60 . The moving sections 70 b move in sequence, with a fixed small volume of liquid passing from one to another as each section 70 b closes to pass the volume to the next and then opens to receive another small volume. The sections 70 b are movable by linear actuators, e.g., solenoid actuators or other actuators (not shown). The volume pumped per unit time is variable if the displacement of the actuator is variable. For example, a three-position solenoid may be used to pump volumes in accordance with either of the two possible positions besides the closed position. Linear actuators that can be programmed to move a particular distance may also be used to control pumping volume. Of course, an inlet valve and an outlet valve may also be used with such a linear peristaltic pump 60 . It will be understood by those with skill in the art that the linear peristaltic pump 60 of FIG. 9 could also operate with a single stationary portion (not shown), with appropriate ridges 76 and recesses 78 , and a plurality of moving portions 70 b mounted to the stationary portion. This would make such a pump less expensive and easier to repair.
Other linear actuation embodiments are depicted in FIGS. 10 and 11 . In FIG. 10 , a infusion pump 120 includes an inlet valve 122 , an outlet valve 124 , a stationary or block section 125 and a shuttle or moving section 126 . The infusion pump 120 manipulates tubing 38 to pump infusion liquid. The valves 122 , 124 are opened and closed by linear actuators 128 , which may be standard, 2-position electric solenoids. The shuttle 126 is moved linearly back and forth by linear actuator 130 . The block and shuttle 125 , 126 may be similar to those depicted in FIGS. 4A , 4 B, 5 A and 5 B, or may be different. The timing of the valve 122 , 124 openings and closings, and the actuation of linear actuators 128 , 130 , i.e., the pumping, are determined by a controller (not shown), to which the linear actuators 128 , 130 are connected, and, in this embodiment, by a computer program in the controller. An infusion pump 120 with a shuttle 126 whose motion is controlled by a linear actuator 130 is known as a linear shuttle infusion pump or, in context, a linear shuttle pump.
FIG. 11 depicts actuation for another infusion pump design with virtually continuous pumping motion. One problem with some designs is that periodically, no fluid is pumped in order to allow the tubing set to fill with more fluid. To eliminate this period of no flow, a second shuttle may be added so that the pump can continue to deliver liquid while the primary shuttle refills. Infusion pump 150 also manipulates tubing 38 to infuse liquid to a patient. In this embodiment, liquid is admitted through inlet valve 152 and is pumped first by primary shuttle 164 . Primary shuttle 164 pumps liquid to secondary shuttle 166 , which is only about half as long as primary shuttle 164 . In this embodiment, there is an intermediate valve 154 between the primary and secondary shuttles 164 , 166 , but there is no outlet valve.
When the primary shuttle has finished pumping and is being replenished, inlet valve 152 is opened and intermediate valve 154 is closed. The secondary shuttle 166 continues the delivery of the fluid. Later, when the intermediate valve is open and the inlet valve is closed, the primary shuttle pumps fluid and fills the secondary shuttle 166 . Since the primary shuttle is twice as long and encounters twice the length of tubing, it pumps about twice as much volume as the secondary shuttle. Other embodiments may be used.
The linear movement of the shuttles and valves described in the above embodiments is easy to understand. However, there are also embodiments in which the tubing for an infusion pump is squeezed or actuated by rotary motion, using a shuttle 420 as depicted in FIG. 6 . Thus, while linear-actuated embodiments depicted in FIGS. 7 to 11 have advantages, other embodiments may achieve more uniform pumping using a single motor and one or more cam surfaces in engagement with the moveable shuttles or moveable sections.
Such an embodiment is further depicted in FIGS. 12 , 13 A and 13 B. Shuttle 420 includes a plurality of ridges 46 and recesses 48 , arrayed along a central transverse channel 460 . As mentioned above, shuttle 420 may also include fingers 422 for restoring the tubing 38 to an open configuration after an individual pumping sequence has been completed. Shuttle 420 includes a pivot 450 with a bore 452 for a pivot pin 454 . The shuttle 420 moves when a motor moves a cam 432 on camming surface 430 . The camming surface 430 , its movement amplified by lever arm 428 , causes shuttle 420 to pivot about pivot 450 and the pivot pin 454 , and forcing the ridges 46 against a length of tubing 38 , thus pumping liquid and infusing liquid into a patient.
Side views of closed and open positions of this embodiment are further shown in FIGS. 13A-13B . In FIG. 13A , stationary block 410 is fixed in place, as is tubing 38 . Shuttle 420 is squeezing tubing 38 in central space 460 . Motor rotates cam 432 clockwise against camming surface 430 , pressing down on camming surface 430 , and through lever arm 428 , urging moving shuttle 420 in a clockwise rotation, upwards against the tubing 38 . When the liquid in the tube 38 has been pumped, the moving shuttle 420 allows the tubing 38 to open and re-fill with the infusing liquid. In FIG. 13B , cam 438 has rotated counter-clockwise, to allow clockwise pivoting about pivot 450 and pivot pin 454 . Tubing 38 can now refill until the next cycle occurs.
FIG. 14 depicts an application with an infusion pump system 100 . In this system 100 , infusion pump controller 112 controls a plurality of infusion pumps 114 , as described above. Each infusion pump 114 receives one liquid for infusing into a patient P, in this instance from containers 102 , 104 , through drips 106 , 108 , and W tubing 38 leading to the respective infusion pumps 114 . The tubing 38 optionally has a connector 110 , for addition of medicaments to the infusion liquid. The pumped liquid in this embodiment is output from each of the infusion pumps 114 through a check valve 116 and then though another length of IV tubing 38 to the patient P. The IV tubing 38 includes a clamp 118 .
It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
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An infusion pump uses an improved shuttle mechanism to more reliably pump liquids in low volumes for medical and other purposes. The improved shuttle uses linear translation and wider, symmetric jaws to grasp infusate tubing and pump liquid infusate through the tubing. Adjustment of the linear motion allows a user to also adjust a pumping volume of the infusion pump. Other shuttles with wider jaws may also pump infusate using a rotary motion. In addition, more than one shuttle, such as two or three shuttles, may be used to approximate continuous pumping. A series of several smaller linear shuttles with sequential actuation may be used as a linear peristaltic pump for general peristaltic pump applications.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to inflators for use in inflatable occupant restraint systems in motor vehicles and, more particularly, to baffle systems for replacing filters used in inflators to remove particulates from combustion gases and to cool the gases.
[0002] Installation of inflatable occupant restraint systems, such as airbags, as standard equipment in all new vehicles has intensified the search for smaller, lighter and less expensive restraint systems. Accordingly, since the inflator used in such systems tends to be the heaviest and most expensive component, there is a need for a lighter and less expensive inflator.
[0003] A typical inflator includes cylindrical steel or aluminum housing having a diameter and length related to the vehicle application and characteristics of a gas generant propellant contained therein. Inhalation by a vehicle occupant of particulates generated by propellant combustion-during airbag-activation can be hazardous. Thus, the inflator is generally provided with an internal, more rarely external, filter comprising one or more layers of steel screen of varying mesh and wire diameter. Gas produced upon combustion of the propellant passes through the filter before exiting the inflator. Particulate material, or slag, produced during combustion of the propellant in a conventional system is substantially removed as the gas passes through the filter. In addition, heat from combustion gases is transferred to the material of the filter as the gases flow through the filter. Thus, as well as filtering particulates from the gases, the filter acts to cool the combustion gases prior to dispersal into the airbag.
[0004] However, the wire mesh filter assembly increases the weight and expense of the inflator. In addition, due to factors such as spatial constraints within the gas generator/inflator and/or the type of gas generant used, combustion of the gas generant may be incomplete when combustion products exit the combustion chamber, resulting in flaming of the combustion products as the gases exit the combustion chamber and enter the wire mesh filter. The porous structure of the wire mesh filter may be unable to contain the flaming combustion products.
SUMMARY OF THE INVENTION
[0005] Various gas generant formulations have been developed in which the particulates resulting from combustion of the gas generant are substantially eliminated or significantly reduced. To solve the problems of reducing airbag inflator size, weight, cost and efficiency, the present invention obviates the need for a conventional filter by appropriate selection of a state of the art gas generant, or a smokeless gas generant if desired, and by incorporation of a baffle tube which cools the combustion gases prior to dispersal of the gases into an airbag. Obviating the need for a filter in an inflator allows the inflator to be simpler, lighter, less expensive and easier to manufacture.
[0006] The baffle tube includes an inner annulus and an outer annulus exterior of and spaced apart from the inner annulus to define a baffle between the inner and outer annuli. A plurality of walls extends between the inner annulus and the outer annulus to connect the outer annulus to the inner annulus, partitioning the baffle into a series of adjacent baffle chambers.
[0007] The baffle tube also provides an extended travel path for combustion gases flowing from the propellant chamber to discharge nozzles in the inflator, thereby allowing time for complete combustion of the gas generant in the inflator.
[0008] In another embodiment, the present invention provides orifices formed in the inner annulus, the outer annulus, and the walls. The walls and the orifices formed in the walls divide the baffle into a series of adjacent fluidly-communicating baffle chambers. Gases flow out of the inner annulus orifice, then sequentially through the fluidly-communication baffle chambers, the out of the baffle via the outer annulus orifice. This arrangement enables the degree of cooling of the gases to be controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is cross-sectional side view of an inflator incorporating a baffle member in accordance with the present invention;
[0010] FIG. 2 is an end view of the baffle member incorporated into the inflator of FIG. 1 ;
[0011] FIG. 3 is a cross-sectional side view of the baffle member shown in FIGS. 1 and 2 taken along section line 3 - 3 of FIG. 2 ;
[0012] FIG. 4 is an end view of a second embodiment of a baffle member in accordance with the present invention;
[0013] FIG. 5 is a partial cross-sectional view of the baffle tube shown in FIG. 4 taken along section line 5 - 5 ;
[0014] FIG. 6 is a partial cross-sectional view of the baffle tube shown in FIG. 4 taken along section line 6 - 6 ;
[0015] FIG. 7 is a partial cross-sectional view of the baffle tube shown in FIG. 4 taken along section line 7 - 7 ;
[0016] FIG. 8 is a partial cross-sectional view of the baffle tube shown in FIG. 4 taken along section line 8 - 8 ;
[0017] FIG. 9 is cross-sectional side view of an inflator incorporating the embodiment of the baffle member shown in FIG. 4 ; and
[0018] FIG. 10 is a schematic representation of an exemplary vehicle occupant restraint system incorporating an inflator including a baffle tube in accordance with the present invention.
DETAILED DESCRIPTION
[0019] FIG. 1 shows a gas generator or inflator 10 , in accordance with one embodiment of the invention. Inflator 10 includes a housing 12 , for example, an aluminum forging. In this embodiment, housing 12 is provided with at least one gas discharge nozzle 14 , or a plurality of gas discharge nozzles 14 arranged in at least one circumferentially and homolaterally extending row. Nozzles 14 may be circumferentially spaced apart substantially evenly. Housing 12 has an integral end closure 16 at one end and an end closure 20 at the opposite end that is crimped in place. A perforated propellant chamber 22 is centrally and longitudinally disposed within housing 12 for containment of propellant grains 24 . Propellant chamber 22 has a longitudinal axis L.
[0020] The inside of the propellant chamber 22 may be provided with a burst foil covering perforations 11 of chamber 22 to facilitate pressure buildup and flame front propagation through propellant grains 24 . End closure 20 accepts an electrical squib 26 in fluid communication with propellant chamber 22 facilitating electric ignition of propellant grains 24 .
[0021] A cap 90 abuts an end portion of propellant chamber 22 and an end portion of a baffle tube 30 (described in greater detail below) to aid in positioning and securing chamber 22 and tube 30 within housing 12 . Cap 90 is shaped so as to form an annular void 91 when seated with respect to chamber 22 and baffle tube 30 . Void 91 allows the passage of combustion gases between plenum 40 and a baffle formed in baffle tube 30 .
[0022] The propellant 24 residing in propellant chamber 22 may be any known smokeless gas generant composition useful for airbag application and is exemplified by, but not limited to, compositions and processes described in U.S. Pat. Nos. 5,872,329, 6,074,502, 6,287,400, 6,306,232 and 6,475,312 incorporated herein by reference. As used herein, the term “smokeless” should be generally understood to mean such propellants as are capable of combustion yielding at least about 90% gaseous products based on a total product mass; and, as a corollary, less than about 10% solid products based on a total product mass. It has been generally found that filters as used in other inflator designs can be eliminated by using compositions having the described combustion characteristics. Other suitable compositions are set forth in the U.S. patent application Ser. Nos. 10/407,300 and 60/369,775, incorporated herein by reference.
[0023] Referring again to FIGS. 1, 2 , and 3 , a baffle tube 30 encloses propellant chamber 22 in a radially spaced relationship to propellant chamber 22 , thereby defining an annular plenum 40 extending between propellant chamber 22 and baffle tube 30 . In the embodiment shown, baffle tube 30 is arranged concentrically with propellant chamber 22 .
[0024] Baffle tube 30 has an inner annulus 32 and an outer annulus 34 exterior of and spaced apart from inner annulus 32 to define a baffle extending between the inner and outer annuli. Inner annulus 32 has a first length D 1 and outer annulus 34 has a second length D 2 . First length D 1 is greater than the second length D 2 . At least one wall 38 extends between inner annulus 32 and outer annulus 34 to connect the outer annulus to the inner annulus. In the embodiment shown, a plurality of circumferentially spaced-apart walls 38 is formed to connect outer annulus 34 to inner annulus 32 . Also, as seen in FIG. 3 , walls 38 are coextensive with a length D 2 of outer annulus 34 . In addition, as shown in FIG. 2 , walls 38 partition baffle tube 30 into a series of parallel baffle chambers 41 extending along a length D 2 of baffle tube 30 between inner annulus 32 and outer annulus 34 .
[0025] In the embodiment shown in FIGS. 1-3 , baffle tube 30 is extruded from an aluminum alloy, although other, alternative materials and fabrication methods are also contemplated. Propellant chamber 22 and baffle tube 30 each have a substantially cylindrical cross-section. However, a wide variety of alternative cross-sectional shapes may be used in accordance with the design criteria and spatial constraints relating to a particular application. For example, propellant chamber 22 and/or baffle tube 30 may have rectangular cross-sections.
[0026] In operation of the gas generator, and referring again to FIGS. 1-3 , upon activation of squib 26 , combustion gases exit propellant chamber 22 through perforations 11 in the propellant chamber. The gases proceed through plenum 40 along the circumference of propellant chamber 22 toward-first end 80 of inner annulus 32 . The gases pass out of plenum 40 , transit annular void 91 extending between plenum 40 and baffle tube 30 , and proceed into baffle chambers 41 . The gases then flow through baffle chambers 41 along length D 2 of outer annulus 34 to exit the inflator via discharge nozzles 14 . Combustion gases exiting propellant chamber 22 are volumetrically expanded and cooled by passing along baffle tube 30 , prior to entering an airbag via discharge nozzles 14 . In addition, passage of the gases through baffle tube 30 allows extra time for full combustion of the gases prior to exiting the inflator, thereby minimizing flaming of the combustion products exiting discharge nozzles 14 .
[0027] FIGS. 4-9 show another embodiment of the baffle tube of the present invention.
[0028] Referring to FIG. 4 , a baffle tube 130 includes the same basic features set forth in the above description of baffle tube 30 , including an inner annulus 132 and an outer annulus 134 exterior of and spaced apart from inner annulus 132 to define a baffle extending between the inner and outer annuli. In addition, a plurality of walls 138 extend between inner annulus 132 and outer annulus 134 to connect the outer annulus and the inner annulus. As shown in FIG. 4 , walls 138 partition baffle tube 130 into a series of parallel baffle chambers 141 extending along the length of baffle tube 130 between inner annulus 132 and outer annulus 134 . However, it may be seen from FIG. 9 that outer annulus 134 in this embodiment is substantially coextensive with inner annulus 132 .
[0029] Also, referring to FIGS. 4-9 , an orifice 160 is formed in each of walls 138 proximate an end of outer annulus 134 for passage of an inflation fluid therethrough. More specifically, referring to FIGS. 4 and 5 , a first orifice 160 - 1 in a first wall 138 - 1 is formed proximate a first end 170 of outer annulus 134 . Referring to FIGS. 4 and 6 , a second orifice 160 - 2 is formed in a second wall 138 - 2 adjacent first wall 138 -l. However, second orifice 160 - 2 is formed proximate a second end 172 of outer annulus 134 , opposite the first end 170 of the outer annulus. This pattern of orifices formed in adjacent walls proximate alternating ends of outer annulus 134 is continued around the circumference of baffle tube 130 . It may also be seen that orifices 160 - 1 and 160 - 2 enable fluid communication between adjacent baffle chambers 141 .
[0030] Referring to FIG. 7 , in addition to orifices formed in walls 138 , an orifice 180 is formed in inner annulus 132 proximate an end portion of the annulus to enable fluid communication between an interior of inner annulus 132 and an associated baffle chamber 141 . Also, referring to FIG. 8 , another orifice 182 is formed in outer annulus 134 proximate an end of the outer annulus to enable fluid communication between a baffle chamber 141 and an exterior of outer annulus 134 .
[0031] Operation of the embodiment shown in FIGS. 4-9 is substantially the same as described above for baffle tube 30 . Referring to FIGS. 4-9 , upon activation of squib 26 , combustion gases exit propellant chamber through perforations 11 in propellant chamber 22 . The gases proceed through plenum 40 along the circumference of propellant chamber 22 toward first end 181 of inner annulus 132 . However, in this embodiment, rather than passing out of plenum 40 along the entire circumference of propellant chamber 22 , the gases exit plenum 40 via orifice 180 formed in first annulus 132 ( FIGS. 4 and 7 ). Gases exiting orifice 180 flow into a baffle chamber 141 - 3 bounded by adjacent walls 138 - 2 and 138 - 3 and outer annulus 134 , then proceed along the length of baffle chamber 141 - 3 until they reach orifice 160 - 3 formed in wall 138 - 3 . At this point, the gases flow through orifice 160 - 3 into the next, adjacent baffle chamber 141 - 4 . The gases then flow along the length of this baffle chamber until the orifice in the next wall 138 - 4 is reached. Thus, the gases flow sequentially from one baffle chamber to another around the circumference of inner annulus 134 until baffle chamber 141 -F is reached. Gases then exit baffle tube 130 via orifice 182 ( FIG. 8 ) formed in outer annulus 134 . An outer plenum 135 fluidly communicates with orifice 182 to provide fluid communication with nozzles 14 . The gases then exit the inflator via discharge nozzles 14 , as previously described.
[0032] In sum, the embodiment shown in FIGS. 4-9 facilitates alternating and sequential fluid flow through each of the channels within the baffle plenum, whereby alternating longitudinal flow of the gas as it proceeds circumferentially about the baffle provides for slag deposition and excellent cooling of the gases.
[0033] As in the previously described embodiment, passage of the gases through the baffle chambers allows extra time for full combustion of the gases prior to exiting the inflator, thereby minimizing flaming of the combustion products exiting discharge nozzles 14 . In addition, combustion gases exiting propellant chamber 22 are volumetrically expanded and cooled by passing along baffle chambers 141 , prior to entering an airbag via discharge nozzles 14 . In this embodiment, the gases are forced through a series of sequential baffle chambers 141 formed in baffle tube 130 to affect the residence time of combustion gases in the baffle tube. This is done to ensure that the gases reside in the baffle for a length of time sufficient to cool the gases to a temperature within a predetermined temperature range prior to the gases exiting inflator 10 . The degree of gas cooling may be controlled by controlling the number of baffle passages 141 formed along baffle tube 130 . In addition, more than one pathway through sequential fluidly-communicating passages may be formed by forming multiple exit orifices in inner annulus 132 and outer annulus 134 , with an appropriate arrangement of walls 138 and orifices formed therein being positioned between an inner annulus orifice 180 and a respective outer annulus orifice 182 .
[0034] Referring to FIG. 10 , any of the baffle tube embodiments described herein may be incorporated into an inflator 10 used in an inflatable vehicle occupant protection system, such as an airbag assembly 200 . Airbag assembly 200 includes at least one airbag 204 and an inflator 10 as described herein coupled to airbag 204 so as to enable fluid communication with an interior of the airbag. Airbag assembly 150 may also be in communication with a crash event sensor 210 including a known crash sensor algorithm that signals actuation of airbag assembly 200 via, for example, activation of airbag inflator 10 in the event of a collision.
[0035] Referring again to FIG. 10 , airbag assembly 200 may also be incorporated into a broader, more comprehensive vehicle occupant restraint system 280 including additional elements such as a safety belt assembly 150 . FIG. 10 shows a schematic diagram of one exemplary embodiment of such a restraint system. Safety belt assembly 150 includes a safety belt housing 152 and a safety belt 151 extending from housing 152 . A safety belt retractor mechanism 154 (for example, a spring-loaded mechanism) may be coupled to an end portion 153 of the belt. In addition, a safety belt pretensioner 156 may be coupled to belt retractor mechanism 154 to actuate the retractor mechanism in the event of a collision. Typical seat belt retractor mechanisms which may be used in conjunction with the safety belt embodiments of the present invention are described in U.S. Pat. Nos. 5,743,480, 5,553,803, 5,667,161, 5,451,008, 4,558,832 and 4,597,546, incorporated herein by reference. Illustrative examples of typical pretensioners which may be used in system 280 are described in U.S. Pat. Nos. 6,505,790 and 6,419,177, incorporated herein by reference.
[0036] Safety belt system 150 may be in communication with a crash event sensor 158 (for example, an inertia sensor or an accelerometer) including a known crash sensor algorithm that signals actuation of belt pretensioner 156 via, for example, activation of a pyrotechnic igniter (not shown) incorporated into the pretensioner. U.S. Pat. Nos. 6,505,790 and 6,419,177, previously incorporated herein by reference, provide illustrative examples of pretensioners actuated in such a manner.
[0037] It should be understood that the preceding is merely a detailed description of various embodiments of this invention and that numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit or scope of the invention. The scope of the invention should not therefore be limited by the preceding description, but should be given its broadest interpretation as stated in the claims appended hereto.
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The present invention provides an inflator for an inflatable restraint system in an automobile. The inflator includes an elongate inflator body containing a baffle tube that cools gases as they are shunted therethrough upon gas generator activation.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to an apparatus for producing thrust force reactions in an automatic transmission, particularly such forces due to transmitting torque between meshing helical gear teeth.
[0003] 2. Description of the Prior Art
[0004] In an automatic transmission a planet pinion carrier supports a set of planet pinions, each member of the set being engaged with a sun gear and a ring gear. Typically, an axial force component, i.e., thrust load, produced due to the helix angle of the meshing gears and pinions and torque transmitted between them, is captured between the sun gear and the ring gear. Thrust load from the sun gear is directed at the ring gear hub, and the thrust load from the ring gear hub is directed at the sun gear. This allows the thrust loads to be cancelled, i.e., reacted by a force of equal magnitude and opposite direction.
[0005] Between the ring gear hub and the sun gear hub, a thrust needle bearing is typically used to react the thrust loads and handle the relative speed between the two components. Under coast load conditions, the planetary ring gear and sun gear may thrust apart from each other. Therefore, thrust from the ring and sun must be captured in both directions.
[0006] In some transmission applications, the speed differential between the ring gear and the sun gear is very high. That high speed differential across a thrust bearing causes significant frictional loss and adversely affects fuel economy.
SUMMARY OF THE INVENTION
[0007] A system producing force reactions in a transmission includes a case including front and rear surfaces, a reaction component, a gearset including a ring gear and a sun gear that transmits a forward force to the front surface, a first path for transmitting a rearward force from the ring gear to the rear surface, a second path for transmitting a forward force from the ring gear to the reaction component, and a third path for transmitting a rearward force from the sun gear to the reaction component.
[0008] The system provides an alternate way to transmit ring gear-to-sun gear thrust loads in cases where the speed differential between the ring gear and sun gear is high.
[0009] No thrust bearing between the sun gear and the ring gear is required or used.
[0010] The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims and drawings. It should be understood, that the description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will become apparent to those skilled in the art.
DESCRIPTION OF THE DRAWINGS
[0011] The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which:
[0012] FIG. 1 is a schematic diagram showing a side view of the kinematic assembly for an automatic transmission for a motor vehicle;
[0013] FIG. 2 is a cross section of an intermediate portion of the kinematic assembly of FIG. 1 ;
[0014] FIG. 3 is a front view of the thrust washer shown in FIG. 4 ; and
[0015] FIG. 4 is a cross section of a front intermediate portion of the kinematic assembly of FIG. 1 ;
[0016] FIG. 5 is a cross section of a rear portion of the kinematic assembly of FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] The assembly 10 FIG. 1 includes an input 12 ; output 14 ; intermediate shaft 16 ; a first planetary gear set 20 having a first sun gear 22 , a first ring gear 24 , a first carrier 26 ; and a set of planet pinions 30 supported on carrier 26 and in continuous meshing engagement with the sun gear 22 and the ring gear 24 .
[0018] A second planetary gear set 32 includes a second sun gear 34 fixedly coupled to sun gear 22 ; a second ring gear 36 ; a second carrier 38 fixedly coupled to the input 12 ; and a set of planet pinions 40 in supported on carrier 38 and in continuous meshing engagement with sun gear 34 and ring gear 36 .
[0019] A third planetary gear set 42 includes a third sun gear 44 fixedly coupled to ring gear 36 ; a third ring gear 46 ; a third carrier 48 ; and a set of planet pinions 50 supported on carrier 48 and in continuous meshing engagement with sun gear 44 and ring gear 46 .
[0020] A fourth planetary gear set 52 includes a fourth sun gear 54 fixedly coupled to ring gear 46 ; a fourth ring gear 56 fixedly coupled by a shell 58 to carrier 26 ; a fourth carrier 60 fixedly coupled to output 14 ; and a set of planet gears 62 supported on carrier 60 and in continuous meshing engagement with sun gear 54 and ring gear 56 .
[0021] A first brake 64 selectively holds ring gear 24 against rotation.
[0022] A second brake 66 selectively holds sun gears 22 , 34 against rotation on the transmission case 124 .
[0023] A first clutch 68 selectively couples ring gear 36 to a clutch housing 70 rotation also on the transmission case 124 .
[0024] A second clutch 72 selectively couples carrier 48 to clutch housing 70 .
[0025] A third clutch 74 selectively couples ring gear 46 to input 12 .
[0026] A fourth clutch 76 selectively couples shell 58 to clutch housing 70 .
[0027] FIG. 2 shows that carrier 26 is secured to shell 58 .
[0028] Clutch housing 70 includes an axial arm 82 formed with internal spine teeth, to which external teeth on the spacer plates 84 of clutch 68 are fixed for rotation with clutch housing 70 . The friction plates of clutch 68 are splined to external spline teeth formed on a ring 85 , which is formed with ring gear 36 .
[0029] Intermediate shaft 16 , which extends along axis 86 on the radial outer side of input 12 , is secured to ring 84 where a snap ring 88 completes the connection. Clutch housing 70 is supported by axially spaced bushings 90 , 92 on the radial outer surface of intermediate shaft 16 .
[0030] Clutch housing 70 includes another axial arm 94 formed with external spine teeth, to which internal teeth on the spacer plates 96 of clutch 76 are fixed for rotation with clutch housing 70 . The friction plates of clutch 76 are splined to internal spline teeth formed on a shell 58 .
[0031] External teeth 98 on the spacer plates of clutch 72 engage internal spline teeth formed on arm 94 of the clutch housing 70 . The friction plates of clutch 72 are splined to external spline teeth formed on carrier 48 .
[0032] Located between bushings 90 , 92 and formed in the hub 100 of clutch housing 70 are four feed circuits. A single balance oil feed supplies automatic transmission fluid (ATF) to the pressure balance volumes 102 , 104 , 106 of clutches 68 , 72 , 76 . Balance dams 103 , 105 , 107 seal the pressure balance volumes 102 , 104 , 106 at the pistons 110 , 112 , 114 of the clutches 68 , 72 , 76 .
[0033] Each of the servo cylinders 69 , 73 , 77 of clutches 68 , 72 , 76 is supplied with actuating pressure through individual circuits formed in the clutch housing 70 . When no actuating pressure is applied to clutches 68 , 72 , 76 , the clutch housing 70 has no fixed connection to any other component of assembly 10 .
[0034] FIG. 4 shows a pump support 120 secured by bolts 122 to the transmission case 124 and supporting the input shaft 12 on a bushing 126 . A hub 128 for brakes 64 , 66 includes a radial arm 130 , secured to the pump support, and an axial arm formed with external and internal axial splines, to which the spacer plates of the two brakes 64 , 66 are secured, respectively.
[0035] The friction discs 132 of brake 66 are connected to external, axial spline teeth formed on a disc 134 , which is secured to the sun gears 22 , 34 through intermediate shaft 18 . The friction discs 136 of brake 64 are connected to internal, axial spline teeth formed on a disc 138 , which is secured to ring gear 24 and is supported between two thrust bearings 140 , 141 located on the carrier 26 .
[0036] The planet pinions 30 of gearset 20 are supported for rotation on a pinion shaft 142 , which is supported on carrier 26 .
[0037] Pump support 120 is formed with a first cylinder 144 containing a piston 146 , which extends though openings 148 into contact with one of the spacer plates of brake 64 . Brake-apply pressure is carried through passages 150 , 151 to cylinder 144 . The openings 148 in hub arm 130 allow an assembler of the brake hub assembly to see though the arm 130 while aligning friction plates 136 with disc 138 .
[0038] Support 120 is also formed with a second cylinder 154 containing a piston 156 , which contacts one of the spacer plates of brake 66 . Brake-apply pressure is carried through passage 158 to cylinder 154 .
[0039] The radial arm 130 of the brake hub 128 is secured to the transmission case 124 such that the arm contacts an axial stop 152 , which limits axial displacement of the arm and provides an axial reaction force to the force of piston 146 applied to the plates of brake 64 and the force of piston 156 applied to the plates of brake 66 .
[0040] Shell 58 is fixed to the carrier 26 of gearset 20 at a snap ring 160 .
[0041] The thrust washer 162 of FIG. 3 is formed with tabs 164 , which engage the forward disc 166 of carrier 26 . A retaining ring 168 secures the thrust washer 162 to carrier disc 166 .
[0042] The lower arrow represents the direction of the thrust force applied to the teeth of sun gear 22 of gearset 20 during positive drive conditions, i.e., when the engine is driving the driven wheels located at the rear of the vehicle.
[0043] The upper arrow represents the direction of the thrust force applied to the teeth of ring gear 24 of gearset 20 during positive torque conditions.
[0044] The forward directed thrust force of sun gear 22 is transmitted directly through a thrust bearing, located between sun gear 22 and the front surface at the pump support 120 , through the pump support 120 , to bolts 122 and into the transmission case 124 , with which bolts 122 are engaged.
[0045] The rearward directed thrust force of ring gear 24 is transmitted by disc 138 to thrust bearing 141 , which applies that thrust force to disc 166 of carrier 26 . Carrier 26 transmits the force to shell 58 .
[0046] The rearward thrust force of ring gear 24 is transmitted axially rearward by shell 58 to ground at a rear surface of the transmission case 124 near the rear of the transmission. No thrust bearing between sun gear 22 and ring gear 24 is required or used.
[0047] As shown in FIG. 5 , shell 58 is secured to a disc 174 , which extends radially toward axis 86 between thrust bearings 176 , 177 . The discs 180 , 182 of carrier 60 are secured mutually. A bearing 184 is secured to the transmission case 124 by a retaining ring 186 . A ring 188 fitted over the outer diameter of output shaft 14 , contacts the carrier 60 and the inner and outer races of bearing 184 where the rearward thrust force of ring gear 24 is reacted at the rear surface of the transmission case 124 .
[0048] Under positive torque conditions, the thrust force of ring gear 24 is transmitted axially rearward by shell 58 to ground on the transmission case 124 near the rear of the transmission. The rearward thrust force of ring gear 24 is transmitted through a path that includes disc 174 , thrust bearing 176 , disc 180 of carrier 60 , disc 182 of carrier 60 , ring 188 , and bearing 184 to an axial thrust force reaction on transmission case 124 .
[0049] Under negative torque conditions, i.e., when the wheels are transmitting torque to the engine, the direction of the ring gear thrust force and sun gear thrust force is reversed relative to the direction of the arrows shown in FIG. 2 .
[0050] Under negative torque conditions, the forward thrust force of ring gear 24 is transmitted through a path that includes disc 138 , thrust bearing 140 , thrust washer 162 , retaining ring 168 , carrier 26 , shell 58 , ring gear 56 , disc 174 and thrust bearing 177 to disc 190 .
[0051] Under negative torque conditions, the rearward thrust force of sun gear 22 is transmitted through a path that includes sun gear 34 , thrust bearing 192 , carrier 38 , input shaft 12 , thrust bearing 202 to disc 190 .
[0052] Disc 190 is an intermediate reaction component, to which the rearward thrust force of sun gear 22 and the forward thrust force of ring gear 24 are applied under negative torque conditions and within which these oppositely directed forces are mutually reacted.
[0053] In accordance with the provisions of the patent statutes, the preferred embodiment has been described. However, it should be noted that the alternate embodiments can be practiced otherwise than as specifically illustrated and described.
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A system producing force reactions in a transmission includes a case including front and rear surfaces, a reaction component, a gearset including a ring gear and a sun gear that transmits a forward force to the front surface, a first path for transmitting a rearward force from the ring gear to the rear surface, a second path for transmitting a forward force from the ring gear to the reaction component, and a third path for transmitting a rearward force from the sun gear to the reaction component.
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CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of Provisional Application No. 60/774,195, filed Feb. 17, 2006, the entire content of which is hereby incorporated by reference in this application.
FIELD
The exemplary illustrative non-limiting implementations relate to systems and/or methods for distributing data to client devices. More particularly, the exemplary illustrative non-limiting implementations relate to systems and/or methods for distributing a game and/or other data to a plurality of client game devices for game play, or the like.
BACKGROUND AND SUMMARY
With the current availability of networking technology, many video games have been designed to allow a number of players to participate in a game from different locations using different machines. Players often will purchase a game, pay to use an online account, connect to a network using a network cable, and compete against other players in a network environment.
Unfortunately, this conventional model has several drawbacks. First, it often is difficult for a group of players to share a common environment and each play their own version of a game competitively against one another. For example, it often is difficult for a group of players to meet in someone's living room and each play their own version of the game against one another. Each machine would need to be provided with its own display, and each player would need a network connection. Alternatively, the players could play on one television using one game machine, but there are limitations on the number of players that can play the game. These conventional limitations occur because the display typically must to be split to show each individual perspective. Additionally, if a single display is used, each player can see the other players' respective viewpoints, thus becoming aware of where those players are going and what those players are doing.
Recently, smaller handheld devices have been provided with wireless networking capabilities, solving the need for each player to have his own display. These devices may allow players to play a game over a local area network, and friends can gather and compete with one another. In the absence of a server, however, one or more of the wireless devices must act as a server, taking on the role of serving required game play information to all of the devices participating in the game. This distribution requirement can burden the devices, which often are designed to play games, rather than to serve requests from other devices.
Even if a server was provided, it often would be handling a plurality of simultaneous download requests from the devices. While a more expensive server might be able to quickly handle these requests more quickly, it nonetheless is desirable to provide an effective solution to this problem where a limited capability server can efficiently handle a plurality of requests without the need for high-priced hardware.
Another possible use of a server would be to provide that server with a plurality of game demonstrations. The server then could be used to respond to a number of game demonstration file requests. However, this arrangement may have the drawback of creating a bottleneck at the server when a large number of file requests are received in a relatively short period of time.
Problems may occur with conventional arrangements because a server typically will receive a number of requests for a game file and process the requests in the order received. This one-at-a-time processing makes the slowdown worse, because all other users must wait while all the requests ahead of them are served. Typically, the requests come at different times, and the server begins processing one request for a file as it is receiving other requests. Any machine later requesting the file has to wait in line until the preceding file requests have been processed by the server.
Thus, it will be appreciated that there is a need in the art to overcome one or more of the above-noted problems. According to one aspect of the exemplary illustrative non-limiting implementations, a download station and/or server is provided whereby a plurality of file requests can be received and processed in an efficient and effective manner. If a plurality of devices are requesting a single file, the server can send packets, or pieces of the file, to each device simultaneously. The devices can then combine these pieces to create the desired file.
Through this method, the server does not have to wait until it is completed processing a single file request before sending the file to a second device. If a device requests a file, the server will begin transmission. If a second device then requests the same file at a later time, the server will continue transmission of the file, and the second device can also receive the same transmission. The later requesting device will receive the packets relating to the presently untransmitted portions of the file, and then can have the previously transmitted portions of the file sent to it when the previous send request is completed. Thus, at the point where the second device moves up to first in a request queue, it has already received a portion of the file, and completing the file request takes a shorter period of time. Additionally, if a third device has then requested the file, the packets sent to complete the file on the second device can also be sent to the third device, and when that device has moved to the front of the request queue, it will then also have a partially completed version of the file in memory.
This method allows a server to process a plurality of requests for a similar file much more quickly than if the server had to send a full copy of the file to each device before it moved on to process the next file request. For example, if five users requested a file, each request coming at a different time, then the four later requesting users would receive all of the packets currently being sent to the first requesting user while the four users were waiting in the queue. Then, when the first user's request was complete, the three remaining later requesting users would also receive the “fill in” packets sent to the second requesting user's device. This method continues until the last user is the first in line, at which point that user's device already has a portion of the file stored therein, allowing completion of the file in a much shorter time. If additional users have subsequently requested the file, they also will receive pieces of the file sent to any users ahead of them in the queue, so the process can continue, potentially perpetually, eliminating the bottleneck associated with multiple file requests.
According to another aspect of the exemplary illustrative non-limiting implementations, a server is provided with a method of tracking file-receipt acknowledgements. This allows the server to know which packets a given device has received. Once the device has moved to the head of the queue, the server can then determine which packets that device needs to complete the file. This prevents the server from having to re-send the entire file each time and relying on the device to fill in the appropriate packets.
According to a further aspect of the exemplary illustrative non-limiting implementations, a client device is provided with a method of tracking received packets. This way, if a device is, for example, fifth in the queue, the device does not redundantly store duplicate information which may be broadcast to it as it moves up in the queue. Because the server is specifically sending out packets based on the needs of the first device in the queue, a device which is fifth will not have its individual packet needs addressed until it is first in the queue. Because more than one device ahead of it may need the same packets from the server, the server would send those packets out based on the needs of the devices ahead of the fifth device as the queue advanced. By tracking the received packets, the device does not attempt to store duplicate versions of the information as it is broadcasted out based on the needs of the preceding devices.
According to another aspect of the exemplary illustrative non-limiting implementations, packets are sent to a plurality of devices simultaneously. Each device will put in its request for a file, and then monitor a broadcast channel for packets pertaining to that file. Whenever a packet is detected, the device checks an internal list of received packets, and if the presently sent packet has not been received and stored, the device stores the packet and flags it as received.
One application for the exemplary illustrative non-limiting embodiments is use in a game demonstration distribution server. A store or other location provided with a plurality of operable game devices can run a server distributing demo versions of games to various devices. This application prevents a user from having to change a cartridge to demo a new game. Accordingly, the server will be able to provide multiple users with new games more quickly, encouraging users to demo and possibly buy multiple games.
While the application of the exemplary illustrative non-limiting embodiments has been discussed in terms of game systems, it will be appreciated that this method could be used in any distribution system where files are distributed from a central server to a plurality of requesting devices.
Certain exemplary illustrative embodiments relate to a method of distributing files from a server to a plurality of client devices in operable communication with the server. The method may comprise, for example, maintaining a queue of requests, with each request being associated with a client device and a client request for a file. One or more needed portions of the file associated with the request first in queue may be identified, with the one or more needed portions of the file corresponding to portions of the file that the client device associated with the request has not yet received. The needed portions of the file may be simultaneously sent for receipt by the client device associated with the request first in queue and for receipt by each client device also having requested the file.
Certain other exemplary illustrative embodiments relate to a system for distributing files. Such systems may comprise a server and a plurality of client devices. The server and the client devices may be in operable communication. Such systems may further comprise a database of files operably connected to the server. The server may be operable to maintain a queue of requests, each request being associated with a client device and a client request for a file; identify one or more needed portions of the file associated with the request first in queue, the one or more needed portions of the file corresponding to portions of the file that the client device associated with the request has not yet received; and simultaneously send the needed portions of the file for receipt by the client device associated with the request first in queue and for receipt by each client device also having requested the file. Each client device may be operable to receive the file portions sent to it by the server.
Yet further exemplary illustrative embodiments relate to a download station comprising a storage location storing a plurality of files for download to client devices and a processor. The processor may be operable to execute the following steps of: receiving requests for files from the client devices; enqueuing the requests in a queue; tracking the files the client devices have requested, portions of the files already downloaded by the client devices, and portions of the files yet to be downloaded by the client devices; and, simultaneously broadcasting at least a portion of the file for receipt by the client devices based in part on the files the client devices have requested, the portions of the files already downloaded by the client devices, and the portions of the files yet to be downloaded by the client devices.
In certain non-limiting implementations, the portions of the file are sent wirelessly, and in certain non-limiting implementations the portions of the file are sent via a single channel. The client devices may be portable game devices, and the files may be games executable by the client devices and/or game-related data interpretable by the client device. The portions of the files may be packets. A completed request may be dequeued based on a checksum of the file associated with the request. A server stripe may be maintained on the server. The server stripe may identify, for each request, downloaded portions of the file associated with the request and not yet downloaded portions of the file associated with the request. A request may be dequeued based on the server stripe. The client devices to which the file will be sent may be determined based at least in part on the server stripe. A client stripe on the client device may be maintained. The client stripe may include portions of the file already received by the client device. Portions of the file may be filtered based on the client stripe, the filtering being performed by the client device.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages will be better and more completely understood by reference to the following detailed description of exemplary illustrative embodiments in conjunction with the drawings, of which:
FIG. 1 shows an exemplary external view of an illustrative game device;
FIG. 2 shows a diagram illustrating an exemplary internal configuration of an illustrative game device;
FIG. 3 shows a representation of an exemplary game server and a plurality of illustrative devices communicating with the server;
FIG. 4 shows a representation of an exemplary client request queuing operation;
FIG. 5 shows a representation of an exemplary client request processing operation performed by a server;
FIG. 6 shows a representation of an exemplary server information receipt processing operation performed by a client;
FIG. 7A shows an illustrative flowchart detailing an exemplary client request queuing operation;
FIG. 7B shows an illustrative flowchart detailing an exemplary queue processing operation;
FIG. 8 shows an illustrative flowchart detailing an exemplary client request processing operation; and,
FIG. 9 shows an illustrative flowchart detailing an exemplary server information receipt processing operation.
DETAILED DESCRIPTION
Referring now more particularly to the drawings, FIG. 1 is an external view of a game device included in the wireless network system shown in FIG. 3 . In FIG. 1 , a game device includes a first liquid crystal display (LCD) 11 and a second LCD 12 . A housing 13 comprises an upper housing 13 a and a lower housing 13 b . The first LCD 11 is disposed in the upper housing 13 a , and the second LCD 12 is disposed in the lower housing 13 b . Each of the first and second LCDs 11 and 12 has a resolution of 256 dots×192 dots. Although the present illustrative game device shows an example where LCDs are used as display devices, any other display devices, such as display devices using, for example, electroluminescence (EL) technology, can be used. Also, display devices of any level of resolution can be used.
The upper housing 13 a has formed therein sound holes 18 a and 18 b for emitting sound from a pair of loudspeakers ( 30 a and 30 b in FIG. 2 , which will be described below). The lower housing 13 b is provided with input mechanisms, such as, for example, a cross switch 14 a , a start switch 14 b , a select switch 14 c , an “A” button 14 d , a “B” button 14 e , an “X” button 14 f , a “Y” button 14 g , an “L” button 14 L, and an “R” button 14 R. Also, a further input mechanism (touch panel 15 ) is mounted on the screen of the second LCD 12 . The lower housing 13 b is provided with a power switch 19 and insertion slots for receiving a memory card 17 and a stylus 16 . The stylus 16 is used for input operations on the touch panel 15 .
The memory card 17 is a storage medium having stored therein a game program and a wireless communication program. The memory card is removably loaded into an insertion slot provided in the lower housing 13 b.
The internal configuration of the game device 10 will be described with reference to FIG. 2 . In FIG. 2 , a CPU core 21 is mounted on an electronic circuit board 20 , which is disposed in the housing 13 . Via a bus 22 , the CPU core 21 is connected to a connector 23 , an input/output interface circuit 25 (labeled “I/F CIRCUIT” in FIG. 2 ), a first graphics processing unit (GPU) 26 , a second GPU 27 , a RAM 24 , an LCD controller 31 , and a wireless communication section 33 . The memory card 17 is detachably connected to the connector 23 . The memory card 17 includes a ROM 17 a , which has stored therein a game program and a wireless communication program, and a RAM 17 b , which has retrievably stored backup data stored therein. The game program and the wireless communication program, which are stored in the ROM 17 a of the memory card 17 , are loaded on to the RAM 24 , and executed by the CPU core 21 . In addition to the game program and the wireless communication program, the RAM 24 stores temporary data, which is obtained by the CPU core 22 for executing the game program, and data for generating a game image. The I/F circuit 25 is operably connected to the touch panel 15 , a right loudspeaker 30 a , a left loudspeaker 30 b , and an operation switch section 14 (shown in FIG. 1 , including the cross switch 14 a , the “A” button 14 d , etc). The right loudspeaker 30 a and the left loudspeaker 30 b are placed inside the sound holes 18 a and 18 b.
Although the example illustrates an example where the game device 10 includes only one CPU core, the device is not so limited. For example, the game device may be provided with a plurality of CPU cores which share processes by the CPU core 21 .
The first GPU 26 is connected to a first video-RAM (VRAM) 28 . The second GPU 27 is connected to a second VRAM 29 . In accordance with an instruction from the CPU core 21 , the first GPU 26 generates a first game image on the basis of data used for image generation stored in the RAM 24 , and writes the image into the first VRAM 28 . Similarly, in accordance with an instruction from the CPU core 21 , the second GPU 27 generates a second game image, and writes the image into the second VRAM 29 . The first and second VRAMs 28 and 29 are connected to the LCD controller 31 .
The LCD controller 31 includes a register 32 . The register 32 stores a value of 0 or 1 in accordance with an instruction from the CPU core 21 . If the value in the register 32 is 0, the LCD controller 31 outputs to the first LCD 11 the first game image written on the first VRAM 28 , and also outputs to the second LCD 12 the second game image written on the second VRAM 29 . Alternatively, if the value of the register 32 is 1, the first game image written on the first VRAM 28 is output to the second LCD 12 , and the second game image written on the second VRAM 29 is output to the first LCD 11 .
The wireless communication section 33 is operable to exchange game process and other data with a wireless communication section 33 of another game device. In the present example device, it is assumed that a wireless communication section has a radio communication function in conformity with IEEE 802.11 wireless LAN standards, for example.
It will be appreciated that the above-described configuration of the game device 10 is merely illustrative and should not be construed as limiting. Also, the game program and wireless communication program may be supplied to the game device 10 not only via an external storage medium, such as the memory card 17 , but also via a wired or wireless communication channel. Alternatively or in addition, the game program and wireless communication program may be previously stored in a nonvolatile storage device within the game device 10 .
According to one aspect of the exemplary illustrative non-limiting implementations, as shown in FIG. 3 , a server 291 is provided to serve out copies of files to one or more requesting devices 295 . The server 291 is configured to communicate wirelessly 293 with the devices 295 , and the devices 295 are also provided with wireless communication 297 capability.
According to an exemplary illustrative non-limiting embodiment, the server 291 receives requests from the devices and broadcasts packets pertaining to requested files. Devices that request a particular file monitor the broadcast channel and receive and store the broadcast packets, assembling them to complete the requested file.
An exemplary representation of a server queuing operation is shown in FIG. 4 . As time passes, requests 301 are received from various clients. The server builds a client requests queue 303 , which is implemented as a first-in, first-out (FIFO) queue in this exemplary representation. If the request 305 from Client 1 is received first, it will be the first request processed. Although this exemplary representation shows a FIFO queue, any type of queue may be used instead of a FIFO queue, such as, for example, a LIFO queue, a priority queue, etc. Also, it will be appreciated that the queue may be implemented as a one or more stacks, as a heap, etc. In the example shown in FIG. 4 , Clients 1 and 3 request File A, and Client 2 requests File B, all for download.
FIG. 5 shows an exemplary representation of a client request processing operation performed by a server. In this representation, a client first in the queue 303 has requested file A 305 . A client second in the queue has requested file B, and a client third in the queue also has requested file A.
In a conventional system, the server would process the requests in a designated order. For example, if a FIFO queue were implemented with such a conventional system, each client would receive their file in the order that they requested it. This means that the client also requesting file A and third in line would have to wait for A to be sent to the first client, for B to be sent to the second client, and then for A to be re-sent to the third client.
According to one aspect of the exemplary illustrative non-limiting implementations, once the first request for A 305 is being processed, the client third in line also can benefit from the processing of this request. Once the first request for A 305 is in, the server checks to see what information that client already has received. In this case, the information already received is designated by the “already sent” area 309 . Then, the server sends all information that had not yet been received by that client, designated by the “downloading file A” area 311 . However, because the server is broadcasting this information and the third client is monitoring the channel for information relating to file A, the third client also can store this information, partially completing the file requested by the third client. Once the server request for A is complete for the first client, the server then will move on and send file B 313 . Finally, after B is sent, the third client only needs to fill in the missing information designated by the “make up” area 315 . Because “make up” area 315 represents only a portion of the file, the client will not need to wait for the entire file to be re-sent in its entirety. Additionally, any other clients having subsequently requested file A will be able to receive the data that is being sent to the third client. This information corresponding to, for example, which clients have requested which files, the pieces of the files already received, and the pieces of the files yet to be received, is tracked in server stripe 307 , which may be located on the server. It will be appreciated that in certain other exemplary illustrative embodiments, other information in addition to and/or in place of the information described herein may be stored. Also, it will be appreciated that the server stripe (or corresponding information store) may be located on the client, in a separate database, etc., depending on the particular implementation.
FIG. 6 shows an exemplary representation of a server information receipt processing operation performed by a client. Because the requested files may be broadcasted to the client in a fragmented form, the client may need to track which packets have already been received. This tracking process allows the client to store the needed packets only once, and prevents a mistaken alteration of a checksum that may be used to check for file completeness. The client tracks the whole file 317 , and it can determine which packets have been received 319 and which packets are still needed 321 . If a packet is received that previously has not yet been received, the client saves the packet and updates the checksum and the marker for that packet. Once the checksum matches the expected sum, the client can stop downloading the file and can process it. It will be appreciated that in certain exemplary illustrative embodiments, the downloaded packets may be inserted into the ultimate file in the correct places, thus potentially eliminating the need to reorder the packet after all data has been received. It also will be appreciated that other data verification methods may be used apart from, or in addition to, checksums, such as wireless checksums.
FIG. 7A shows a flowchart detailing an exemplary client request queuing operation. When the server receives a request from a client, the server needs to order those requests in some fashion. According to an exemplary representation, the server checks for incoming client requests 323 . If a request is received 325 the server adds the client request to the queue 327 . If no requests are received, or after the server has added the request to the queue, the server returns to looking for client requests 323 .
FIG. 7B shows a flowchart detailing an exemplary queue processing operation. First, the server checks to see if there are any requests pending in the queue 329 . If the server finds a pending request 331 , the server processes that request and sends out the desired information. If the server does not find a request, or when the current request processing is complete, the server then checks the queue again for requests 329 .
FIG. 8 shows a flowchart detailing an exemplary client request processing operation. If the server finds a request pending in the queue, the server must then process that request. According to one aspect of an exemplary illustrative non-limiting implementation, the server checks markers which it has stored for a particular client. These markers may be set when earlier packets were broadcast while the current request was still pending in the queue. For example, if a file has ten packets, and packets two, three and seven have been sent while the current client was waiting in the queue, then markers corresponding to that client are set for those parts because the server has gotten a confirmation that the packets were received. Thus, the server knows which packets the client has not received and can send them out. In certain exemplary illustrative embodiments, alternatively, or in addition, the markers may be stored on the client side device.
Upon processing the client request, the server determines whether or not packets are still needed by this client 337 . If the file is complete, then the server can exit 339 processing for this particular request. If the client still needs packets, the server can send out a needed packet 341 and update the corresponding client marker 343 . The server must also check the queue to see if other clients were requesting the same file 349 . For example, if there were ten other clients requesting the same file, then the server would update the markers corresponding to those clients 351 so that when any of those clients reached the front of the queue, the server would not waste time re-sending a packet that that client had already received. The server then checks the packet markers for the current file 335 to determine again if any packets are additionally needed 337 .
FIG. 9 shows a flowchart detailing an exemplary server information receipt processing operation. According to one aspect of the illustrative exemplary non-limiting implementations, a client may use a checksum to verify that a file has been fully received. If the client updates this checksum based on the packets received, then it would be best if the client does not redundantly store a packet and mistakenly alter the checksum based on this redundant store. To that end, the client may be provided with a method to protect against redundant packet storage, an exemplary flow of which is shown in FIG. 9 .
The client, which knows it is waiting for a request, checks for incoming data 353 . If incoming data is detected 355 , the client checks an internal set of data markers 357 . These markers are similar to the markers kept by the server and aid the client in determining which pieces of information still need to be stored. If the client determines that a particular packet is already present, the client does not store the packet and update the checksum. Using the example from above, the client would have markers two, three, and seven set, indicating that if packets two, three, or seven were detected, the client would not store that data again. If a particular packet does not need to be stored by a particular client, the client then goes back to checking for new incoming packets.
If the client does not yet have a detected packet, the client will store a copy of that packet 361 and adjust the checksum accordingly. The client then checks the checksum 363 to determine if the file is complete 365 . If the checksum matches the expected sum, then the file is complete and the client no longer needs to look for the file. If the file is not complete, then the client can update the corresponding data maker and continue to look for additional incoming packets. The client may also notify the server 371 that the piece of information was received.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
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Striped Multiplexing Download Queue software facilitates and increases throughput for client-server downloads through a limited communication device. In the “DS Download Station” application, this is used to queue many requests and to broadcast download segments to requesters seeking the same data. This works by employing a “download stripe” on both the server and client. The download stripe on the server side tracks acknowledgements from clients per download segment. On the client side, the stripe tracks received segments to account for duplicate data. Requesters are queued on a first-come first-serve basis. Requesters in the queue may receive segments of downloads while waiting in queue, if the client at the front of the queue is downloading the same file. This recursively saves waiting time for clients in the queue.
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RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 10/209,053, filed Jul. 30, 2002 (now U.S. Pat. No. 6,700,995). The Ser. No. 10/209,053 application is a continuation in part of co-pending U.S. patent application Ser. No. 09/553,084, filed Apr. 19, 2000 (now U.S. Pat. No. 6,590,996). Each of these patent documents is herein incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates steganography and more particularly to the digital watermarks.
BACKGROUND AND SUMMARY OF THE INVENTION
[0003] The technology for applying digital watermarks to images and to other types of data is well developed. For example see issued U.S. Pat. No. 5,748,783, issued U.S. Pat. No. 5,768,426 issued U.S. Pat. No. 5,822,435 and the references cited in these patents. Also various commercially available products (such as the widely used image editing program Photoshop™ marketed by Adobe Corporation) have image watermarking capability. There are many other patents and much technical literature available relating to the application of digital watermarks to images and to other types of data.
[0004] Co-pending application Ser. No. 09/553,084 (now U.S. Pat. No. 6,590,996) describes a technique of color adaptive watermarking. With the technique described in application Ser. No. 09/553,084 a change in an image attribute such as luminance (or chrominance) is mapped to a change in color components such that the change is less visible application Ser. No. 09/553,084 describes the “scale to black” and the “scale to white” techniques for applying watermarks. By using the scale to white method for colors with a high yellow content such as yellow, red and green, and by using the scale to black for blue, cyan and magenta a watermark with a lower visibility and the same detect ability can be embedded in an image.
[0005] It is known that when an image is printed on a standard offset press, the relationship between the digital value of a color and the amount of ink actually applied by the press is not linear. FIGS. 1 illustrates the dot gain curve for a typical standard offset printing press. The horizontal axis gives a digital value of a color and the vertical axis indicates the amount of ink actually transferred by the press. The shape of the dot gain curve of offset printing presses is well known.
[0006] As a result of the dot gain curve illustrated in FIG. 1, when an image containing a watermark is printed on an offset press, a watermark signal in the shadows (i.e. in an area with more ink) is reduced and a watermark signal in the highlights (i.e. in an area with less ink) is amplified. Note that the slope of the dot gain curve is different in the shadow area and in the highlight area. Thus, the same amount of change in color value produces a different amount of change in the ink applied in the two different areas. The present invention provides a technique which insures that a watermark signal is preserved in an printed image as accurately as possible not withstanding the fact that the dot gain curve of the printing press is not linear.
[0007] With the present invention, the image data is first modified in accordance with the forward dot gain curve of a printing press, next the watermark “tweak” values (i.e. the watermark change values) are calculated for this modified image data. The calculated “tweak” values are then modified in accordance with the backward dot gain curve of the printing press. The modified tweak values are then added to the original image data values to produce a watermarked image. The watermark image is then printed on the printing press. The result is that the “effective” tweak on printed paper is not materially affected by the dot gain curve of the printing press.
BRIEF DESCRIPTION OF FIGURES
[0008] [0008]FIG. 1A shows a forward dot gain curve.
[0009] [0009]FIG. 1B shows a backward dot gain curve.
[0010] [0010]FIG. 2 illustrates scaling to black.
[0011] [0011]FIG. 3 illustrates scaling to white.
[0012] [0012]FIG. 4 is a program block flow diagram of the operation of the preferred embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS
[0013] Co-pending application Ser. No. 09/553,084, filed Apr. 19, 2000 (Now U.S. Pat. No. 6,590,996) describes a system for watermarking images. The system described in application Ser. No. 09/553,084 inserts watermarks in images by selecting and modifying colors to obtain approximately equal visibility for all colors. The preferred embodiment of present invention, as described herein, is described as a modification of the system described in application Ser. No. 09/553,084. The object of the modifications is to compensate for the dot gain curve of a printer. The entire specification of application Ser. No. 09/553,084 is hereby incorporated herein by reference.
[0014] It is desirable that a watermark embedding algorithm produce luminance changes with approximately equal visibility through color space. Adaptive color embedding as described in application Ser. No. 09/553,084, selects the colors that are modified to produce a required luminance change, in a way that obtain approximately equal visibility for all colors. The dot gain correction provided by the preferred embodiment described herein approximately compensates for the non-linear effect of the printing process, so that a desired percentage change is achieved on press (that is, in the amount of ink applied to create the image). It is noted that the slope of the dot gain curve is different in the shadow area and in the highlight area. Thus, the same amount of change in color value produces a different amount of change in the ink applied in the two different areas. The preferred embodiment insures that a watermark signal (i.e. a change value) is preserved in a printed image as accurately as possible not withstanding the fact that the dot gain curve of the printing press is not linear.
[0015] As explained in application Ser. No. 09/553,084 a watermark can be applied to images using either a scale to black or a using a scale to white technique. With the scale to black technique, the image pixel is like a vector between black and the pixel color value. The vector is increased or decreased as shown in FIG. 2. That is, FIG. 2 illustrates the color changes for a luminance change utilizing the scale to black technique. The following table lists for each color, the colors that are modified as a result of a luminance change. The table also indicates the degree to which the modification is visible.
[0016] For Scale to Black:
Color Colors Modified Visibility of the change yellow cyan/magenta high red cyan high green magenta medium Blue Yellow low Cyan Magenta/yellow low Magenta Cyan/yellow low
[0017] [0017]FIG. 3 illustrates the color changes that occur with a scale to white technique. The scale to white technique obtains the same luminance change as the scale to black technique; however, when scaling to white the image pixel is a vector between white and the pixel color value as shown in FIG. 2. The following table lists for each color, the colors modified as the result of a luminance change. The table also indicates the degree to which the modification is visible.
[0018] For Scale to White
Color Colors Modified Visibility of change yellow yellow low red magenta/yellow low green cyan/yellow medium Blue Cyan/magenta high Cyan Cyan high Magenta Magenta medium
[0019] By using the scale to white method for colors with high yellow content such as yellow and red, and scale to black for blue, cyan, magenta and green a lower visibility mark can be made with the same detectability. Scaling to white results in the watermark being applied mainly to the dominant colors, and scaling to black implies that the watermark is mainly in the secondary colors.
[0020] When images are printed on an offset press, it is known that there is not a straight line relationship between the digital value of the color at any point in the image and the corresponding amount of ink applied to the paper at that point. This is known as dot gain. FIG. 1A shows the forward dot gain curve. That is the relationship between the digital value of a color and the amount of ink actually applied. FIG. 2B shows a backward dot gain curve. That is, FIG. 2 indicates the value needed in order to get a particular amount of ink on the paper.
[0021] The following is a list of 256 values that generate a curve as shown in FIGS. 1A. That is, the following is a list of 256 positions on the vertical axis for 256 positions (i.e. for 0 to 255) on the horizontal axis.
0 7 12 18 22 26 29 32 34 37 39 42 44 46 48 50 52 54 55 57 59 60 62 64 65 67 68 70 71 73 74 76 77 78 80 81 83 84 85 86 88 89 90 91 93 94 95 96 97 99 100 101 102 103 104 105 106 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 135 136 137 138 139 140 141 142 143 144 144 145 146 147 148 149 150 150 151 152 153 154 155 155 156 157 158 159 160 160 161 162 163 164 164 165 166 167 168 168 169 170 171 171 172 173 174 175 175 176 177 178 178 179 180 181 181 182 183 184 184 185 186 186 187 188 189 189 190 191 191 192 193 194 194 195 196 196 197 198 198 199 200 201 201 202 203 203 204 205 205 206 207 207 208 209 209 210 211 211 212 213 213 214 215 215 216 216 217 218 218 219 220 220 221 222 222 223 224 224 225 225 226 227 227 228 229 229 230 230 231 232 232 233 234 234 235 235 236 237 237 238 238 239 240 240 241 241 242 243 243 244 244 245 246 246 247 247 248 249 249 250 250 251 251 252 253 253 254 254 255
[0022] The following is a list of 256 values that generate the curve shown in FIG. 1B. That is, the following are the vertical values for 256 positions (i.e. 0 to 255) on the horizontal axis.
0 1 1 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 7 7 7 8 8 9 9 9 10 10 11 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 19 19 20 20 21 22 22 23 23 24 25 25 26 27 27 28 29 29 30 31 31 32 33 34 34 35 36 36 37 38 39 40 40 41 42 43 44 44 45 46 47 48 49 49 50 51 52 53 54 55 56 57 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 86 87 88 89 90 91 92 93 94 96 97 98 99 100 101 103 104 105 106 107 109 110 111 112 113 115 116 117 118 120 121 122 123 125 126 127 129 130 131 132 134 135 136 138 139 140 142 143 144 146 147 149 150 151 153 154 156 157 158 160 161 163 164 166 167 168 170 171 173 174 176 177 179 180 182 183 185 186 188 189 191 193 194 196 197 199 200 202 203 205 207 208 210 211 213 215 216 218 219 221 223 224 226 228 229 231 233 234 236 238 239 241 243 244 246 248 250 251 253 255
[0023] It is noted that different offset processes produce different amounts of dot gain; however, with most offset processes, the dot gain curve has the shape shown. For some particular offset processes, the actual values may to 50 or 75 percent of the values given above. The values used in any particular application should be the values appropriate for the particular printing process that will be used to print a particular image.
[0024] [0024]FIG. 4 is a block program flow diagram of a program for the preferred embodiment of the invention. The process begins with an image 401 which is in the CYMK color space. As indicated by block 402 , the values for each color in the image are first modified in accordance with the values of the forward dot gain curve. This generates a modified image.
[0025] Next as indicated by block 403 calculations are made using the modified image to determine the “tweak” (i.e. the change) values needed to embed a particular watermark in the modified image. This calculation can be done using known watermarking techniques. In the preferred embodiment, the tweak values are calculated using the technique available in the commercially available Photoshop image editing program. However, in other embodiments, other watermarking techniques can be used.
[0026] The tweak values are next modified in accordance with the backward dot gain curve values as indicated by block 404 . Next as indicated by block 405 , the modified tweak values are added to the values in the original image 401 , thereby producing a watermarked image. Finally as indicated by block 406 the watermarked image is printed using an offset press which has the forward and backward dot gain values used in blocks 402 and 404 .
[0027] The watermark can then be read from the printed image using known watermarks reading techniques.
[0028] In an alternate embodiment of the invention, the tweak values are added to the modified image values and then the resultant image is modified in accordance with the backward dot gain curve values; however, it has been found that in most instances, the process described in FIG. 4 eliminates some rounding errors.
[0029] In some applications, it has been found desirable to add back a constant that controls the amount of the scale to black signal when a color with high yellow-blue saturation is being embedded. This is sometime necessary, since some cameras are insensitive in the blue channel, so changes in yellow are not detected very well.
[0030] In general to dot gain correction is only applied to the CMY channels, and not to K channel. However, if desired the dot gain correction can be applied to all the channels.
[0031] The preferred embodiments described above relate to the dot gain curve for offset printing processes. It is noted that other processes such as ink jet printing have a different type of dot gain curve. The invention can be applied to most types of printing processes by merely using a dot gain curve appropriate to the particular process.
[0032] Images watermarked using the embodiments described above can be read with conventional watermark reading techniques. Naturally as is conventional the watermark reading technique used should coincide with the particular technique used to generate the change values, that is, with the technique used to watermark the image.
[0033] While the invention has been described with respect to watermarking images it should be understood that the principle is applicable to other types of data.
[0034] The preferred embodiment relates to an image in the CYMK color space. Other embodiments using the same principles can operate on images in various other color spaces.
[0035] While the invention has been shown and described with respect to preferred embodiments, it should be understood that various changes in form and detail may be make without departing from the spirit and scope to the invention. The scope of the invention is limited only by the appended claims.
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Image color values are modified in accordance with printing process characteristics. Digital watermark signal representations are determined and modified in accordance with the characteristics. The modified signal representations are combined with the original image color values. The image is then printed by the printing process. The resulting printed image includes a watermark that is not materially affected by the printing process characteristics.
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BACKGROUND OF THE INVENTION
This invention relates to an auxiliary front wheel drive system for a vehicle, and more particularly, to such a system which utilizes implement system pressurized fluid flow for driving said front wheels.
Systems of the general type disclosed herein are shown in U.S. Pat. No. 3,458,005 to Malm et al., U.S. Pat. No. 3,480,099 to Nighswonger et al., and U.S. Pat. No. 3,481,419 to Kress et al. In such systems, a vehicle includes motors for driving the front wheel thereof, such motors being of the hydraulic type to be driven by fluid under pressure, in a series or parallel mode. Pressurized fluid supplied to each motor actuates a clutch associated with that motor so that a front wheel of the vehicle is drivingly engaged with the motor.
In any of the clutch engaging systems of these patents, it will be seen that the fluid pressure to be applied to such clutch for engagement thereof may be directed from either the fluid conduit of the motor associated with such clutch, or the fluid outlet conduit of such motor. While it will be seen that, in such situations, the higher of such two fluid pressures may be applied to the clutch for the engagement thereof, such clutch may in other situations be exposed to both the higher and lower pressures defined by such motor inlet and outlet conduits, resulting in a less than maximum fluid pressure being applied to such clutch to actuate it.
In addition, in the area of such clutch in any of these three patents, no means are provided for preventing excessive pressure buildup in the clutch.
Of more general interest in this area are U.S. Pat. No. 2,818,699 to Clemson, U.S. Pat. No. 3,153,908 to Lawrence, U.S. Pat. No. 3,184,994 to Stahl, U.S. Pat. No. 3,186,506 to Leach, U.S. Pat. No. 3,255,840 to Tangen, U.S. Pat. No. 3,272,576 to Budzich, U.S. Pat. No. 3,272,279 to Budzich, U.S. Pat. No. 3,302,741 to Brazuk, U.S. Pat. No. 3,354,977 to Swift, U.S. Pat. No. 3,391,753 to Anderson, U.S. Pat. No. 3,361,223 to Baver, U.S. Pat. No. 3,415,334 to Vriend, U.S. Pat. No. 3,469,648 to Cannon, U.S. Pat. No. 3,447,547 to Kress et al., U.S. Pat. No. 3,493,067 to Rumsey, U.S. Pat. No. 3,522,861 to Middlesworth et al., and U.S. Pat. No. 3,579,988 to Firth et al.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an auxiliary drive system for a vehicle which incorporate fluid motors and fluid pressure actuated clutches which engage such motors with wheels of the vehicle, wherein the fluid pressure actuated clutches are properly supplied with the highest of the fluid pressures in the motor inlet and outlet means.
It is a further object of this invention to provide a system which, while fulfilling the above object, includes means for preventing excessive fluid pressure buildup in such clutches.
It is a still further object of this invention to provide a system which, while fulfilling the above objects, is simple in design and efficient in use.
Broadly stated, the invention is in a vehicle having a fluid motor associated with a wheel thereof, and a fluid pump and a fluid supply associated therewith. Inlet conduit means connect the pump and motor for supplying fluid under pressure from the pump to the motor, and outlet conduit means extend from the motor, the fluid flowing from the motor through such outlet conduit means. The fluid passes through the motor to drive the motor. Clutch means are engageable upon an application of fluid pressure thereto to effect a driving connection between the motor and wheel, and are disengageable to disconnect the motor and wheel. The improvement in such system comprises means for applying the greater of the fluid pressures in the inlet and outlet conduit means to the clutch means for inducing engagement thereof, and blocking the lesser of the fluid pressures in the inlet and outlet conduit means from the clutch means.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects of the invention will become apparent from a study of the following specification and drawings, in which:
FIG. 1 is a schematic illustration of a first embodiment of a front wheel drive system of a vehicle; and
FIG. 2 is a schematic illustration of a second embodiment of a front wheel drive system of the vehicle.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Shown in FIG. 1 is an auxiliary hydrostatic front wheel drive system for use with the front wheels 90 of a vehicle (not shown). The vehicle includes a main power source and rear wheels to be driven thereby, as is well known. The main power source of the vehicle drives the pump 35 which is utilized to operate the front wheel drive system of FIG. 1.
The operation of the combination of a motor 56, clutch 86, and wheel 90 associated therewith, and also the combination of the motor 62, clutch 86, and wheel 90 associated therewith, will be later described in detail. However, it should be understood that the motor 56 and clutch 86 combination are mounted in fixed positions relative to each other, and are in turn pivotally mounted to an end of an axle (not shown) so as to be pivotable relative thereto to allow changing of the attitude of the wheel 90 associated therewith, as is well-known. Likewise, the motor 62 and clutch 86 combination are in fixed positions relative to each other, and are pivotally mounted to the opposite end of such axle (not shown) to allow changing of the attitude of the wheel 90 associated therewith. Appropriate well-known means may be utilized to interconnect the structures associated with the ends of such axle so that the wheels 90 of the vehicle may be moved to chosen pivotal attitudes, so that the vehicle may be steered. It is to be understood that the conduits associated with the motors 56,62 and clutches 86 are flexible so as to allow such proper turning of the wheels.
Referring to FIG. 1, reduced pilot pressure in a conduit 10 is selectively communicated to a three-position pilot operated forward and reverse valve 12 via solenoid operated pilot control valve 14 and 16, which are in communication with conduits 18 and 20, respectively. Reduced pressure is also supplied from conduit 10 to a solenoid operated pilot control valve 22 which is selectively actuatable and permits the pilot signal to be communicated to control valve 24 and control valve 26 via conduits 28 and 30 respectively. The solenoid operated control valves 14,16 and 22 receive an electrical signal for actuation thereof which corresponds to the ground speed of the vehicle. An electrical on/off switch, not shown, that is selectively controlled by the operator, may block the current flow in lines 32, which places the system in its neutral condition when the front wheel drive is not required. When the vehicle transmission, not shown, is in the neutral position, or the electrical switch described above is blocking lines 32, the solenoid operated pilot signal control valves 14,16 and 22 vent the pilot signal lines to tank 34.
To operate the front wheel drive system, the operator closes the electrical switch described above, and shifts the vehicle transmission to the first position, forward. An electrical signal is then communicated to solenoid operated pilot control valves 14 and 22 which communicate pressurized fluid in conduit 10 to conduit 18, which shifts the forward and reverse control valve to its forward position "A." Pilot signal pressure in conduit 10 is also communicated to conduit 28 and conduit 30 by control valve 22, which shifts control valve 24 and control valve 26, respectively, to their second positions. Pressurized fluid in the vehicle implement system which is supplied by a variable displacement pressure compensated pump 35 associated with a fluid supply 37 is directed by a conduit 36 to a priority valve 38. Priority valve 38 maintains a predetermined minimum pressure in the implement system. When the pressure in conduit 36 is sufficient, priority valve 38 will shift to communicate pressurized fluid to conduit 40 and through valve 12 to conduit 42. Control valve 26 in its shifted position communicates the fluid from conduit 42 to conduit 44 and through flow divider/combiner valve 46, which proportionally divides the flow and directs it by conduits 48 and 50 to control valve 24 which is shifted to its actuated position to communicate flow to conduits 52 and 54.
Conduit 52 connects to conduit 53 which in turn is connected to fixed displacement hydraulic motor 56, and conduit 54 is ultimately connected to fixed displacement hydraulic motor 62 via conduits 58 and 60. The pressurized inlet fluid entering the motors 56 and 62 via the above path will cause them to rotate. Conduits 61 as shown are motor case drains and communicate motor leakage to tank 34. Outlet fluid from motor 56 flows through conduit 64 and is directed back to tank via conduit 66, valve 26, conduit 68, conduit 70, valve 12 and conduit 72. A pilot operated check valve 74 is normally open to tank during operation of the drive motors 56,62, and will be discussed later in conjunction with the operation of clutches associated with the motors 56,62. Fluid flow discharged from motor 62 is directed to tank 34 via conduits 76,78,70, valve 12 and conduit 72.
As seen in FIG. 1, a conduit 81 communicates with conduits 52,53, a conduit 84 communicates with conduits 64,66 and a conduit 88 communicates with a clutch 66, which is engageable upon application of fluid pressure in the conduit 88 to effect a driving connection between motor 56 and a wheel 90 of the vehicle. Likewise, a conduit 83 communicates with conduits 58,60, a conduit 85 communicates with conduits 76,78, and a conduit 94 communicates with a clutch 86 which is engageable upon application of fluid pressure in the conduit 94 to effect a driving connection between the motor 62 and a wheel 90 of the vehicle. These clutches are, of course, disengageable to disengage the respective motors and wheels.
A shuttle valve 80 connects conduits 81,84,88, so that the greater or higher of the fluid pressure in the conduits 81 (motor inlet pressure) or 84 (motor outlet pressure) is directed into the conduit 88 to engage the clutch 86, the shuttle valve 80 meanwhile blocking the lesser of the fluid pressures in conduits 81,84 from the conduit 88.
Likewise, a shuttle valve 92 connects conduits 83,85,94, and applies the greatest or highest of fluid pressure in conduits 83,85 to engage the clutch 86, meanwhile blocking off the lower of the fluid pressures in conduits 83,85 from the clutch 86.
The pilot operated check valve 74 establishes the necessary back pressure in the system at startup to insure clutch actuation. Once the system is in operation, the pilot operated check valve 74 is unseated by pilot pressure in conduit 40 to permit free flow to tank 34.
The above description details the operation of the parallel flow concept which establishes the low speed, high torque operation of the drive motors 56,62.
When the vehicle transmission control is shifted to its second speed range, the solenoid operated pilot signal valve 22 is vented to tank, which allows control valve 26 to shift back to its normal, or first or series position, as shown in FIG. 1, and allows control valve 24 to shift to its deactuated position, also as shown in FIG. 1. Pilot signal valve 14 remains actuated, and permits flow from the implement system to pass through conduits 36,40 and 42 to control valve 26 and further through conduits 82 and 53 to motor 56. Outlet flow from motor 56 passes through conduits 64 and 66, through control valve 26, conduits 58 and 60 and through motor 62, conduit 76, conduits 78 and 70, and through valve 12 and conduit 72 to tank 34. Actuation of the clutches 86 is achieved in a manner similar to that previously described.
When the vehicle transmission control is shifted to the reverse position, the solenoid operated pilot signal valve 16 communicates reduced pilot pressure to valve 12 which shifts the valve 12 to its position "C" allowing implement system flow to be directed to the motors in a direction opposite that previously described, and ultimately back to tank 34. Thus, inlet and outlet flows are reversed.
Referring to FIG. 2, this system is similar to that of FIG. 1 in that it uses the series-parallel flow concept and directional control valve to obtain two motor speeds in the forward direction and one motor speed in reverse. Clutch actuation in this system is achieved in a similar manner in that it utilizes shuttle valves 80,92 to pick a higher system pressure for actuating the clutches 86 by means of conduits 91, 93, equivalent to conduits 88,94 of FIG. 1, through which fluid pressure is supplied to the clutches 86. However, pressure reducing valves 96 are included in conduits 91,93 to prevent excessive pressure buildup in the clutches 86. Such valves are exposed to fluid pressure in the conduits 91,93 and will shift upon a level of pressure being achieved in conduits 91,93 to prevent further pressure buildup in the clutches 86.
It is to be noted that, in order to achieve series drive of the motors, the control valve 98 is shifted into its first or series position (as shown in FIG. 2). Parallel drive of the motors is provided only with the control valve 98 shifted into its second or parallel position, and the control valve 100 shifted from its deactuated position (as shown in FIG. 2) to its actuated position. (As set forth above, the system of FIG. 1 is substantially the same in this area.) The shifting of the valves 98,100 into such parallel and actuated conditions in the FIG. 2 embodiment takes place upon application of fluid pressure which is operatively associated with the valves 98,100 to so shift them upon a certain level of fluid pressure being achieved, the level of such fluid pressure being determined by the speed of the vehicle.
The forward and reverse valve 102 is manually actuated by the vehicle operator to any one of its three selectively actuated positions.
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A vehicle such as a motor grader includes a hydrostatic auxiliary front wheel drive system which utilizes implement system pressurized fluid flow to drive a pair of fixed displacement hydraulic motors, such motors being drivingly connected to cause rotation of the front wheels. A pilot operated series-parallel valve in combination with a flow divider allows the motors to be driven in series or in parallel. A directional control valve is selectively responsive to operator control, and clutch actuation is accomplished automatically by directing a controlled portion of system fluid to such clutches to overcome the normal spring bias thereof.
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STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore.
CROSS REFERENCE TO OTHER RELATED APPLICATIONS
Not applicable.
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to transducers, and more specifically to an acoustic wave transducer that functions based on the same transduction principles found in cicadas, designed by means of efficient computation of the higher order (i.e., nonlinear) kernels in a Volterra or Wiener expansion used to validate the transducer model.
(2) Description of the Prior Art
Cicadas emit one of the loudest sounds in all of the insect population despite their relatively small size. A cicada's sound production system allows for propagation distances of approximately one quarter of a mile for the periodic cicada and beyond a mile for some annual cicadas. The sound level for some species is over 120 dB relative to (the intensity of a plane wave of) pressure equal to 20 micro-Pascals. This represents an exceptional transmission distance for the size of the sound production system. The cicada's highly effective sound-production system occupies a physical space typically less than 3 cubic centimeters. Males create sound by flexing a pair of ridged abdominal membranes called tymbals. The cicada uses its tymbal muscle to pull the tymbal, which causes the tymbal ribs to buckle releasing sound impulses. The sounds made by these tymbals are amplified by the hollow abdomen functioning as a tuned resonator. The cicada song has been classically modeled using linear mathematical methods. Unfortunately, these linear methods are insufficient for a true model of the system because the non-elastic (i.e., nonlinear) buckling tymbals of the cicada sound production system are essential to the acoustic level and propagation of the sound. The present invention is a method and apparatus that emulates the cicada sound production system. This bio-inspired method and apparatus potentially provides a precision method for improved detection, classification and generation of acoustic signals in air and in water.
Most acoustic signal processing methods in use today are based on a first order (linear) kernel estimation. Whenever higher order kernels exist in physical systems, these kernels will masquerade as noise in a first order approximation. By uncovering the higher order kernels in physical systems, new possibilities exist for achieving significant computational gains in receiver signal-to-background interference levels not possible using linear methods. Moreover, the signal content of these higher order kernels, once detected, can provide new and useful information about an acoustic signal source.
Previous work in acoustic signal processing has demonstrated a utility in the application of the Volterra series expansion and other nonlinear methods for the exploitation of signals via application of a Volterra and/or Wiener signal processing procedure to measure and quantify higher-order non-linearities. The present invention teaches a signal processing breakthrough that significantly alleviates the “Curse of Dimensionality” (COD) in the characterization of nonlinear physical systems; namely, the reduction in the number of coefficients used to describe the higher order (i.e., nonlinear) kernels in the Volterra series expansion used to validate the finite element (FE) model that is instrumental in the development of the transducer model. The latter technique provides the means to evaluate simultaneously from a wide band excitation, all the inter-modulation products up to a specified order by greatly reducing the number of coefficients in the higher order kernel estimation to a manageable set that can be easily manipulated by current personal computers.
SUMMARY OF THE INVENTION
It is a general purpose and object of the present invention to provide a method and apparatus that emulates the cicada sound production system.
It is also an object to uncover the higher order kernels in acoustic signal processing methods.
This object is accomplished by a signal processing breakthrough that significantly alleviates the “Curse of Dimensionality” (COD) in the characterization of nonlinear physical systems; namely, the reduction in the number of coefficients used to describe the higher order (i.e., nonlinear) kernels in the Volterra series expansion. The latter technique provides the means to evaluate simultaneously from a wide band excitation, all the inter-modulation products up to a specified order by greatly reducing the number of coefficients in the higher order kernel estimation to a manageable set that can be easily manipulated by current personal computers used to validate the finite element (FE) model that is instrumental in the development of the transducer model.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated and understood by referencing the following detailed description when considered in conjunction with the accompanying drawings wherein:
FIG. 1A is an illustration of the stages of a Finite Element bio-acoustic transducer design;
FIG. 1B is an illustration of the stages of a bio-acoustic transducer design;
FIG. 1C is an illustration of the stages of a bio-acoustic transducer design;
FIG. 2A is an illustration of schematic of the two degree of freedom coupled vibration system of the cicada sound generation system that simulates the tymbal excitation and abdominal cavity;
FIG. 2B is an illustration of schematic of the two degree of freedom coupled vibration system of the cicada sound generation system that simulates the tymbal excitation and abdominal cavity;
FIG. 3 is an illustration of the depiction of stiffness parameter as a function of time in the FE model;
FIG. 4 is an illustration of a graph of radiated acoustic power (W) versus time (s) during one sequence of three buckling ribs;
FIG. 5 is an illustration of a preferred embodiment of the apparatus for a nonlinear sound production system of the present invention;
FIG. 6 is an illustration of the measurement and fitting procedure;
FIG. 7 is an illustration of the flow chart of the method of the Volterra signal processing for a third-order solution;
FIG. 8 is an illustration of the method of the Volterra signal processing for a third-order solution;
FIG. 9 is an illustration of a spectral representation of second order modeled output of the bio-acoustic signal; and
FIG. 10 is an illustration of diagonal strips in f 1 ,f 2 -plane depicting second-order kernel construction.
DETAILED DESCRIPTION OF THE INVENTION
To generate an accurate description of the acoustics of cicada sound production system, the physical dimensions and anatomical features of the cicada must be understood through a Finite Element (FE) model. The general functionality of the cicada's anatomy is accurately described in the scientific literature; although, the explicit details of the functionality are not known. Previous apparatus that has been based upon the cicada tymbal buckling does not accurately represent the structural acoustics produced by the insect as the present invention does. In a preferred embodiment, the core anatomy cicada sound production system is executed in a Finite Element (FE) computer model. The acoustical sounds are created by invoking an appropriate forcing function applied to the tymbal in order to simulate muscle motion (i.e., contraction and expansion) and tymbal rib buckling. In order to produce the acoustics, these anatomical structures are placed in a surrounding fluid of air and the forcing function loads are applied to the appropriate elements in the model to generate the sound. Alternatively, this finite element model is simulated in water in which hydrodynamic effects are compensated for as well.
There are several steps in the translation of the FE model to a working device. The material properties designed by the FE model are translated into a transducer device as illustrated in FIGS. 1A , 1 B, and 1 C. The illustrated steps translate the cicada sound production system into the physical and material properties and dimensions (i.e., the spring-mass-damper system), which describe the apparatus for emulation of man-made acoustic sounds. (F Applied shown in the FIG. 1C is determined by emulating an experimental data set obtained from an actual tymbal signal). The tymbal 10 , air sac 12 and Tonpilz transducer 14 electrical wire diagrams in the FIGS. 1A , 1 B and 1 C show the transformers, resistors, and capacitors required to convert material properties to an actual physical system in order to generate the desired acoustics. The process of translation of the FE model to a working device leads to the developing a two coupled systems model representing the (1) vibration of the tymbal plate and (2) the abdominal air sac. The cicada sound production system is modeled as a coupled two degree of freedom vibration system. Two schematics of the system are shown in FIG. 2A (the spring mass damper system 19 ) and 2 B (the resonating cavity 21 ). The primed quantities indicate transformed quantities.
The input force provided by the muscle contraction and expansion and subsequent inner and outer buckling of the tymbal ribs is represented by the force F T (t). The subscripts (T and A) stand for tymbal and abdomen, respectively. The tymbal vibrational system is represented by the equivalent stiffness K T (x T ), moving mass M T (x T ), and loss element R T . The tymbal displacement is given by x T . The lumped elements of the spring mass damper system 19 of FIG. 2A are modeled as nonlinear elements, and the nonlinear stiffness of the tymbal is modeled as a function of the tymbal displacement x T as shown in FIG. 3 .
The wiring model 19 in FIG. 2A adjusts the different compliances of the tymbal motion in the outward and inward direction, as different slopes of the stiffness in the expansion or compression region. Adjustments are also made to the hardening or softening behavior found in the spring constant from the stiffness. Similarly, the consecutive mass loading of the tymbal by the buckled ribs is included via a nonlinear inertial element M T (x T ) and damper. The second schematic system, FIG. 2B , is akin to a ‘linear acoustic’ Helmholtz resonator, only it has been modified and adapted to the specific purpose of this invention as a ‘nonlinear acoustic’ resonator 21 . The equivalent stiffness is K A (x A ), inertial element is M A (x A ), and internal damping is R Int (x A ). The acoustic displacement is represented by the displacement x A . Here, the stiffness K A (x A ) is based on the air volume in the abdominal sac. The inertial element M A (x A ) is that of the moving mass of the tympana, and the inertial damping R Int (x A ) represents acoustic damping within the air in the abdominal sac. Again, nonlinear representations of the lumped elements are used. The schematic is terminated by the radiation resistance R Rad , which represents the radiation of the sound away from the tympana. The excitation force F T is generated by the successive buckling of the ribs.
Equation (1) is a nonlinear system of ordinary differential equations representing the models in FIG. 2A and 2 B. The nonlinear system is solved numerically. The nonlinear model computation is accomplished based on certain assumptions. Namely, the nonlinear stiffness is accomplished by motion of the tymbal plate mass. For example, the moving mass of the tymbal plate is the sum of the tymbal plate mass, one third of the mass of the dorsal resilin pad, and the mass of the first buckling rib during the buckle of a rib. The next buckling event, the mass of the second rib is added to the tymbal moving mass. Finally, for the third buckle the mass of the third rib is added to the moving mass. The example given is for a simple three rib cicada.
y
1
=
x
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The results of the dynamic analyses were done with slightly different values of the dynamic stiffness, once the ribs start to buckle, the stiffness of the ribs were set to zero, and the only remaining stiffness was the dorsal pad. FIG. 4 shows the radiated acoustic power for the combination of tymbal displacement and acoustic pressure in the abdominal air sac. The time window used for the analyses is a little larger than the time to have three ribs buckle. Finally, the analysis yields a peak power of 30 mW for this model. Several variations that include additional nonlinear effects and refinements are also possible for someone skilled in the art. These include variations in: nonlinear stiffness, successive rib buckling, tymbal plate mass, air sac mass and abdominal cavity volume.
Referring now to FIG. 5 there is a preferred embodiment of the apparatus for a nonlinear sound production system of the present invention. FIG. 5 provides an overview description of the electronics and components required to create a transducer 100 based upon the cicada nonlinear sound production system. In a preferred embodiment, there is an electronic control suite 20 containing a programmable digital processor with a non-volatile memory component 22 (e.g. PC104 or GumStix®). The processor 22 is programmed with an algorithm designed to operate a series of or arrays of discrete ceramic elements 24 made of a piezo-electric material arranged in a housing 26 . The housing 26 is filled with a resin 28 that holds the discrete ceramic elements 24 in place at the transducer face 34 . The housing 26 also contains an electronic circuit board 30 that is wired to each discrete ceramic element 24 . The arrays of discrete ceramic elements 24 are actuated with voltage inputs originating from an electrical power source 32 (in a preferred embodiment the power source 32 is a direct current source such as a battery) initiated by the electronic control suite 20 , which generate compression and contractions in each discrete ceramic element 24 in a non-linear manner that emulates the cicada sound production system. The electronic control suite 20 regulates which discrete ceramic elements 24 are activated in series or parallel for particular regions within the element array. Therefore, the discrete ceramic elements 24 generate mode shapes on the transducer face 34 that emulate the cicada tymbal face. The discrete ceramic elements 24 control activation replaces the physical tymbal ribs functionality. Therefore, the complex mode shapes produced at the transducer face 34 are analogous to the complex modes created by the cicada sound production system. The resonating chamber 36 emulates the cicada abdomen resonator and the operculum 38 is the opening from which sound propagates. The transducer 100 forms similar waveforms as the cicada sound production system, with similar acoustic efficiency. The acoustic components generate nonlinear waveforms by emulating the elastic buckling impulse trains of the tymbal ribs repeated several hundred times a second.
The Volterra-Wiener model assesses the higher-order dynamics present in both the cicada and transducer 100 acoustic wave forms. Then, the FE-based model provides the material properties used in the design of the transducer model. Using the experimental data obtained from live insect vocalizations, the Volterra-Wiener expansion model authenticates the emulated sound outputs. The nonlinear sound production system apparatus creates the high-order structural acoustics found in actual cicada vocalizations.
Nonlinear system excitation x(t) is sampled at frequency f s Hz, resulting in time-sampling increment Δ=1/f s seconds and sampled sequence {x(nΔ)}. For simplicity of notation, the Δ symbol will be suppressed in equation (2) and is comparable to the x T in equation (1) and the excitation sequence will be denoted simply by {x(n)}. Later in equation (2), Δ will be kept in order to stress the time dependence. Moreover, the excitation input sequence {x(n)}, the actual sampled output sequence {z(n)} and model sampled output sequence {y(n)} in equation (2) and is equivalent to the y solution in equation (1), which is referred to as waveforms.
Consider a time-invariant nonlinear system with actual sampled input sequence {x(n)} and actual sampled output sequence {z(n)}, both of which are sampled at the same rate f s and recorded simultaneously. The causal time-invariant Volterra model sampled output sequence {y(n)} is then given, to third order, by:
y ( n ) = h 0 + ∑ k 1 = 0 K - 1 h 1 ( k 1 ) x ( n - k 1 ) + ∑ k 1 = 0 K - 1 ∑ k 2 = 0 K - 1 h 2 ( k 1 , k 2 ) x ( n - k 1 ) x ( n - k 2 ) + ∑ k 1 = 0 K - 1 ∑ k 2 = 0 K - 1 ∑ k 3 = 0 K - 1 h 3 ( k 1 , k 2 , k 3 ) x ( n - k 1 ) x ( n - k 2 ) x ( n - k 3 ) ≡ y 0 + y 1 ( n ) + y 2 ( n ) + y 3 ( n ) , ( 2 )
where h 0 , h 1 , h 2 , h 3 are the zeroth-order through third-order (time-invariant) time-domain kernels of the Volterra expansion. It is assumed that the Volterra kernels h 0 , h 1 , h 2 , h 3 are represented with the same time-sampling increment as used for the nonlinear system input and output waveforms x(n) and z(n). It is also assumed for simplicity that the same “memory length” K in equation (2) is appropriate for all three orders of these kernels. Different sizes K 1 , K 2 , K 3 of the summations may be considered in an alternative form of equation (2).
The unknowns in the Volterra expansion in equation (2) are the four kernels h 0 , h 1 , h 2 , h 3 which appear linearly in the model output y(n). A least squares approach is used to fit model output y(n) to the actual measured nonlinear system output z(n); See FIG. 6 . The major problem associated with the Volterra expansion is the curse of dimensionality (COD), namely, the extreme number of coefficients (kernel values) required in equation (2). At first order, the number of coefficients that must be determined is M 1 =K; at second order, the number of coefficients is approximately M 2 =K 2 /2; and at third order, it is approximately M 3 =K 3 /6. In the normal equations that arise in least squares, the size of the data product matrix that must be inverted is M×M. The M 2 ×M 2 case can often be solved with current-day computer random access memory (RAM), but the M 3 ×M 3 matrix will often not fit into RAM. If a simultaneous fit of all the components in equation (2) to measured nonlinear system output z(n) were of interest, the desired RAM requirements could exceed that which is achievable by modern computer memory storage allocations.
The present invention describes a method devised of partitioning the various kernels so that meaningful useful estimates are obtainable at higher orders and can be obtained by a modern computer. Referring to FIG. 7 , the procedure entails performing a least squares calculation on the acoustic wave form to obtain approximations of kernels h 0 , h 1 , h 2 , h 3 from the zero order to the third order 50 , determining a number of indices k 1 , k 2 , k 3 for each kernel h 0 , h 1 , h 2 , h 3 through Fourier analysis 52 , transforming the time domain kernels into the frequency domain kernels 54 , assessing which frequency domain kernels h 0 , h 1 , h 2 , h 3 have a frequency content with the highest decibel level and discarding the remaining frequency domain kernels 56 , segmenting the wide-frequency band kernels into overlapping sub-bands and discarding the overlap between sub-bands while maintaining the summed up sub-band partitions with the full frequency extent 58 , placing the whole kernels back into the time domain from the frequency domain using an inverse fast Fourier transform for each kernel 60 and solving for y(n) with least squares for the least amount of indicies and redundant frequencies 62 .
As illustrated in FIG. 8 for the case of a second order kernel, model response y(n) is compared with nonlinearity z(n), using a least squares procedure as shown in FIG. 6 . The comparison can be conducted band-by-band in frequency. The equations determining the best kernels (h 0 , h 1 , h 2 , h 3 ) are the solutions (y(n)) of simultaneous linear equations in the least squares sense. The usefulness of this technique is illustrated in FIGS. 8 and 9 .
Referring to FIG. 9 , a spectral representation of the second-order modeled output for a cicada bio-acoustic signal in air is plotted. Note there are several peaks in the spectral plot near 0, 6, 8 and 12 kHz, lower amplitude peaks around 14 and 17 kHz, and an even lower peak near 31 kHz. The peaks in the frequency spectrum provide some information about the non-linearity from which the spectrum is generated (for example, a peak amplitude at 6 kHz) but do not provide the details of all the possible nonlinear interactions (i.e., all the frequency inter-modulation contributions) that are used to derive the 6 kHz amplitude peak in the spectrum. However, Volterra equations are derived and a model is calculated to include all contributions from inter-modulation products in the kernel estimate that contribute to the (modeled) broadband spectrum of the acoustic signal ( FIG. 9 ). A two dimensional template for the third-order kernel construction of the feasible inter-modulation products is shown in FIG. 10 .
The equations for this illustrated second-order kernel are as follows:
y 2 ( n Δ)=Δ 2 ∫∫df 1 df 2 exp[ i 2π( f 1 +f 2 ) nΔ]H 2 ( f 2 ) X ( f 1 ) X ( f 2 ). (3)
Note that this is not a double Fourier transform; there is only one time variable on the right-hand side, namely, nΔ, where Δ is the sampling interval. Note also that the only place that time variable nΔ appears on the right-hand side of equation (3) is with the frequency combination f 1 +f 2 . If second-order Volterra output y 2 (nΔ) is to have frequency content only in the band (f a ,f b ) for purposes of fitting to a corresponding filtered version of z(nΔ) and if X(f) is broadband, then second-order frequency-domain kernel H 2 (f 1 ,f 2 ) must be restricted to be nonzero only for
f a <f 1 +f 2 <f b (4)
(and the corresponding negative frequencies). This condition allows complex exponential in equation (3) to take on frequency variation only in the band (f a ,f b ). The region in equation (4) is definitely not square in f 1 ,f 2 space. Rather, see the shaded regions in FIG. 10 .
Equation (4) describes an infinite strip at angle −45° in the f 1 ,f 2 plane, with perpendicular width (f b −f a )/√{square root over (2)}=W/√{square root over (2)}. However, the fundamental region is limited to be below the +45° line in the f 1 ,f 2 plane. In addition, frequency f b cannot exceed the limit F. The shape of this finite confined strip in the f 1 ,f 2 plane is similar to the shape of the state of Nevada. This is the restricted region of f 1 ,f 2 space in which H 2 (f 1 ,f 2 ) is allowed to be nonzero if y 2 (nΔ) in equation (3) is to contain frequency content limited to the frequency range (f a ,f b ).
One of the advantage of the present invention over the prior art is the alleviation of the COD at second and higher orders. This break through provides new possibilities for characterization of nonlinear physical systems. There are a number of applications including acoustic transmission and reception devices in water (e.g., sonar) and in air (e.g., sound systems). Another advantage of the present invention is the ability to quantify nonlinear systems obtained from Volterra-Wiener methods, which extends to analyzing nonlinear channels. Utilizing the cicada's efficient sound propagation technique broadens the knowledge of constructive and deconstructive interference, which may extend to higher frequencies applications.
In light of the above, it is therefore understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
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A method and apparatus is taught for a signal processing breakthrough that significantly alleviates the “Curse of Dimensionality” (COD) in the characterization of nonlinear physical systems; namely, the reduction in the number of coefficients used to describe the higher order (i.e., nonlinear) kernels in the Volterra series expansion. The latter technique provides the means to evaluate simultaneously from a wide band excitation, all the inter-modulation products up to a specified order by greatly reducing the number of coefficients in the higher order kernel estimation to a manageable set that can be easily manipulated by current personal computers used to enhance a finite element (FE) model that generates a bio-inspired acoustic transducer model.
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FIELD OF THE INVENTION
The invention relates to a method of and an apparatus for controlled regeneration of a diesel soot filter of a diesel engine.
BACKGROUND OF THE INVENTION
It is known that diesel soot filters having a porous wall permit gaseous components of the exhaust gas to pass, while they prevent the passage of solid particles which result, above all, from coagulation of carbon molecules and heavy hydrocarbons.
The soot particles deposited in the diesel soot filter and, in the course of operation, progressively clogging the diesel soot filter can be decomposed by thermal (burning), catalytic, or other processes to regenerate the diesel soot filter.
Thermal regeneration with the engine running, e.g. during operation of a vehicle equipped with the same, may cause an uncontrolled rise of the reaction speed of the combustion of the particles collected in the diesel soot filter under stochastic conditions when the regeneration is released automatically. That may lead to an inadmissible temperature increase and result in partial or total fusion or destruction of the diesel soot filter.
It has been suggested to measure the temperature of the exhaust gas downstream of the diesel soot filter (DE 38 06 219 A1) to avoid uncontrolled combustion. If a predetermined maximum admissible temperature is exceeded in this case valves upstream and downstream of the diesel soot filter are actuated by means of an electronic unit so that all of the exhaust gas will be discharged through a bypass circumventing the diesel soot filter. Thus the diesel soot filter, temporarily, is disconnected entirely from the exhaust gas stream.
Although operation through the by pass makes up only a small percentage of the overall operating time of the engine, muffling equipment is need to dampen the annoying noise which is created during the bypass operation. Moreover, it is undesirable from the ecological point of view to discharge unscrubbed exhaust gases without filtering into the atmosphere even for a short time, as occurs in bypass operation.
It is likewise known (CH 663 253 A) to divide a particle filter in the exhaust gas tract of an internal combustion engine, especially one with exhaust gas supercharging, into two sections connected in parallel, namely one thermally well insulated "high temperature flow zone" and one "low temperature flow zone". By means of a control flap, exhaust gas will flow through the low temperature flood only at low engine load and through both flow zones at high engine load, by corresponding adjustment of the control flap. The results hereof, apart from frequent particle combustion, is that the exhaust gas supercharger connected downstream of the exhaust gas tract always is fed quickly with exhaust gas of sufficient temperature in order to prevent the so-called "turbo hole" upon depression of the accelerator pedal. However, protection against uncontrolled burn off of deposited particles in the flow zones cannot be achieved by the measure according to the Swiss patent.
SUMMARY OF THE INVENTION
It is the object of the invention to indicate a method and an apparatus to regenerate diesel soot filters in diesel engines with which effective protection against damage or destruction of the diesel soot filter can be achieved in simpler manner than before and under avoidance of the inconveniences of bypass operation.
A method according to claim 1 and an apparatus according to claim 2 serve to solve that problem.
According to the invention, the diesel soot filter is divided into a plurality of sections which are connected in parallel in the exhaust gas flow and of which at least one is adapted to be shut off totally or in part from the exhaust gas stream in response to the particular exhaust gas temperature prevailing at the outlet of the respective section.
While the reaction in the isolated section is reduced or interrupted, the mass flow rate through the remaining section or sections not disconnected of the diesel soot filter is increased. Hereby the reaction speed of the thermal regeneration in these remaining sections is reduced.
If the maximum admissible temperature should be surpassed also in one of the remaining sections not shut down of the diesel soot filter then this section, too, will be disconnected from the exhaust gas stream. This is continued in accordance with the invention until the mass flow rate through at least the last remaining section of the diesel soot filter has risen to such a degree that the reaction which was started will be broken off or "extinguished".
In this manner effective protection is provided against damage or destruction of the diesel soot filter by uncontrolled combustion of the deposited particles, making a bypass and thus the emission of unfiltered exhaust gas into the atmosphere during bypass operation dispensable as well as expensive muffling equipment.
Advantageous modifications of the invention are indicated in the subclaims.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be described further by way of example, with reference to the accompanying diagrammatic drawings, in which:
FIG. 1 shows a four cylinder diesel engine comprising a downstream diesel soot filter according to the invention in the exhaust gas tract;
FIG. 2 is a diagram of the reaction speed of regeneration above the mass flow rate of the diesel soot filter;
FIG. 3 shows a six cylinder engine comprising a modified diesel soot filter according to the invention;
FIGS. 4, 5, and 6 illustrate further modifications of diesel soot filters according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a four cylinder diesel engine 1 in the exhaust gas tract 3 of which diesel soot filters 2, 4, and 6 are installed, with no bypass being provided to bridge the diesel soot filters. These three diesel soot filters are installed parallel to each other in the exhaust gas tract 3 and comprise a common inlet 5 from which individual inlet pipe ends 5a, 5b, 5c are branched off, each opening into an associated diesel soot filter 2, 4, 6, and individual outlet pipe ends 7a, 7b, 7c which each start from a diesel soot filter 2, 4, 6 and are joined in a common outlet 7.
In the inlets 5a, 5b, 5c, a throttling member 10, 12, 14 each--in other words as many throttling members as diesel soot filters 2, 4, 6--are provided. Also, thermocouples 9, 11, 13 are provided in the outlets 7a, 7b, 7c for individually detecting the exhaust gas temperatures of the three diesel soot filters. Their output signals are input into an electronic unit 100 which controls the throttling members. The throttling members 10, 12, 14 here are designed as throttle flaps.
From time to time, soot particles deposited in the diesel soot filters are regenerated by combustion due to a temperature increase during operation or by means of exhaust gas throttling. In the case of enforced regeneration all the throttling members 10, 12, 14 are actuated simultaneously by the electronic unit 100.
That diesel soot filter 2, 4, or 6 behind which the exhaust gas temperature measured exceeds a given temperature is shut off from the exhaust gas stream by blocking the corresponding throttling member 10, 12, or 14 for protection against uncontrolled burning during regeneration. The closing of the respective inlet 5a, 5b, or 5c takes place totally or partly by means of the corresponding throttling member 10, 12, or 14 upon an ON/OFF signal or an analog actuating signal emitted by the electronic unit 100. This unit 100 receives the output signals of the thermocouples 9, 11, 13 as input signals.
The reaction speed of the combustion started of the soot accumulated in the diesel soot filter at constant exhaust gas temperature is a function of the mass flow rate m. The dependence of the reaction speed w of the combustion on the mass flow rate m is illustrated qualitatively in the form of a diagram in FIG. 2. If the temperature downstream of the diesel soot filter 2 loaded with a quantity G of particles (FIG. 1) exceeds the maximum admissible exhaust gas temperature this filter 2 is blocked partly or even totally by actuation of the corresponding throttle flap 10. And, as a consequence, the mass flow is reduced under m 1 . Now the main exhaust gas flow rate is passed through the diesel soot filters 4 and 6. Accordingly, the mass flow rate m through these filters 4 and 6 is increased to above m 2 . This means that the reaction speed w in all filters is reduced, as may be gathered from the diagram of FIG. 2. In the event that the exhaust gas temperature surpasses the maximum admissible value downstream another filter, e.g. downstream of filter 4, this filter is throttled or closed in the same manner as filter 2 previously. This leads to a further increase of the mass flow rate m through the filter 6 in which, therefore, the reaction speed is reduced by such an amount that a reaction possibly initiated will be broken off or "extinguished".
Normal operation of the system is resumed when the exhaust gas temperature downstream each diesel soot filter 2, 4, 6 drops below the maximum admissible value.
It is a prerequisite for full protection against uncontrolled combustion of the amount of particles deposited in the diesel soot filter that the mass flow rate in the last filter causes break-off or "extinction" of the reaction already when the diesel engine is running idle.
Thus the volume and number of diesel soot filters are determined in advance for a particular diesel engine.
FIG. 3 illustrates an arrangement of a six cylinder diesel engine comprising four diesel soot filters 16, 18, 20, 22. Here, too, a throttling member 24, 26, 28, 30 each in the corresponding inlets, not designated here, and a thermocouple 32, 34, 36, 38 each in the corresponding outlets, not designated here, are associated with each diesel soot filter.
The individual shutoff of the diesel soot filters from the exhaust gas stream is effected stepwise by means of the electronic unit, not shown here, in the same manner as with the embodiment according to FIG. 1, with at least one diesel soot filter being left in operation in the final stage.
The throttling members may be embodied by throttle flaps or poppet valves.
FIG. 4 shows a diesel soot filter with two inlets 50, 51 and consisting of a monolith. The exhaust gas is introduced through inlet 51 which does not incorporate a throttling member into section 52 of the soot filter. Exhaust gas introduced through the inlet 50 flows through section 57. This inlet 50 is provided with a throttling member 40. Corresponding thermocouples T1 and T2 are installed centrally downstream of the outlet cross sections of both sections 52 and 57.
Protection against uncontrolled combustion is warranted by actuation of the throttling member at the inlet 50, regardless of which one of the two thermocouples T1 or T2 recorded an inadmissible temperature. By virtue of the dimensioning of the tubular inlet 51, the section 52 is selected to be so small that the resulting mass flow during idle running already is so great that the combustion of the deposited soot is delayed or even interrupted.
Other than with the embodiments shown in FIGS. 1 and 3, the one illustrated in FIG. 4 (and also the embodiments according to FIGS. 5 and 6) can do with but one throttling member 40, whereby the number of movable and, therefore, sensitive parts is reduced and the structure simplified. Surprisingly, the omission of the throttling member for section 52 does not affect the forced regeneration by exhaust gas throttling.
Regeneration by particle burnoff is forced by the closing of the only blocking member 40. Thereby, an increase is obtained of the exhaust gas counterpressure and, accordingly, of the temperature upstream of both sections of the diesel soot filter.
Protection against uncontrolled burning usually becomes effective at low to medium rotational speeds or at low load. Under these circumstances the driver does not notice any deterioration of the driving characteristics due to the increased counterpressure caused by the reduced outlet area since he can push down further on the accelerator pedal to achieve the desired performance. If, on the other hand, the protection should occur in the range of maximum rotational speed or performance the protection process can be interrupted by a kickdown switch. As is known, protection against uncontrolled burning in this operating range is taken over by the cooling effect of the exhaust gas stream. By analogy, throttling that has commenced can be cancelled if the driver should demand full power.
FIG. 5 shows a diesel soot filter which includes two sections, namely a bigger section 67 and a smaller one 62, and no blocking members in the inlets 60, 61. A single blocking member is embodied by a thermostat 64 which is disposed in the common outlet passage of the two sections 62, 67 and through which pass the exhaust gas streams through the sections 62, 67. When the thermostat expands it closes the outlet 63 of the greater section 67 at a predetermined exhaust gas temperature. With this embodiment, monitoring of the temperatures at the filter outlet and, therefore, an electronic control unit become superfluous since the thermostat 64 automatically takes over the protection against uncontrolled burning of both sections 62, 67 when the given exhaust gas temperature is reached.
With this embodiment the thermostat 64 consists of a closed corrugated tube which expands axially under elevated internal pressure. It is provided with a suitable filling of a substance (such as sodium) which will evaporate when a certain temperature is reached, thereby causing a quick rise of the internal pressure. Thereby, the thermostat 64 is extended elastically and the outlet 63 becomes blocked.
A variant of the embodiment according to FIG. 5 is presented in FIG. 6 where small and big sections 72, 77 of a filter 71 are formed as two sections of a monolith 72. Exhaust gas flows through the sections via a common inlet 70. As with the embodiment according to FIG. 5, a thermostat 74 in the form of an axially expandable corrugated tube is arranged in the outlet 73 of the great section 77 in such a way that it will automatically close the outlet 73 thereof when a predetermined temperature is reached.
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With a method of controlled regeneration of a diesel soot filter of a diesel engine the diesel soot filter is divided into a plurality of sections which are connected in parallel in the exhaust gas tract and into at least one of which the influx of exhaust gas is blocked in response to the exhaust gas temperatures measured downstream of the diesel soot filter. When the maximum admissible exhaust gas temperature downstream of the diesel soot filter is exceeded this section, consequently, is shut off in part or even completely from the exhaust gas stream so that the mass flow rate through the corresponding filter section is reduced or even cut off, while the mass flow rate through the remaining sections is increased in a way so as to again control the regeneration or even discontinue it.
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BACKGROUND OF THE INVENTION
In the field of high-speed printing devices which are especially suitable for use in connection with electronic data processing systems, the wire matrix type of printer has come into increasing use. In this type of printer, letters, numbers and symbols are formed from a series of dots produced by the impact of the ends of a plurality of wire elements on record media, most customarily in combination with an ink ribbon which provides the ink needed to produce a mark on the record medium being printed upon.
One problem which has arisen in connection with use of printers of the wire matrix type is that of fatigue breakage of the print wires and associated springs employed to return the wire to a non-printing position after a printing stroke. This breakage results from bending and vibration of the print wires caused by the high force employed to drive the wires over a short distance to impact upon the record medium being printed upon or the ink ribbon associated therewith. In order to reduce or eliminate such breakage, in some prior art structures, the individual print wires have been confined within print head blocks or units, or within tubes or coil springs anchored in the printer framework. However such structures have the disadvantages of increasing the parts and labor costs, and also tend to impede the movement of the printer wires by frictional engagement between the wires and the tubes. This, in turn, has led in some instances to further structural alterations of the printers to provide means for lubricating the wires within the tubes, thereby additionally increasing the cost and complexity of the assembly.
In another approach to solution of this problem, tubular elements have been placed on the print wires to ride freely thereon and exercise a vibration dampening function, as disclosed and claimed in the co-pending United States patent application Ser. No. 758,521, filed Jan. 11, 1977, inventors Nelson et al., now U.S. Pat. No. 4,060,161, issued Nov. 29, 1977, assigned to the assignee of the present application.
SUMMARY OF THE INVENTION
This invention relates to a printer of the matrix type, and more particularly relates to such a printer which includes means for dampening vibration and bending of the print elements to reduce or eliminate fatigue failure.
In accordance with one embodiment of the invention, a printing mechanism comprises frame means including at least one transverse support member located intermediate of the ends of the frame means; a plurality of elongated printing elements extending through and supported by said support member in an array of generally conical configuration and capable of being driven in an axial direction to effect printing; driving means operatively connected to said printing elements for axially driving said printing elements; and dampening means of generally conical configuration disposed completely within said array of elongated printing elements, secured to said support member and having a surface from which each of the elongated printing elements is physically separated when at rest and when in normal axial movement, said dampening means being positioned to limit undesired transverse movement and vibration of said elongated printing elements during and following operation thereof by said driving means.
One advantage of the present invention is that dampening of the bending and vibration of the print elements is achieved without frictional drag on the print elements since the print elements are not normally in contact with the dampening means and are free to move axially in normal printing movement without engaging the dampening means.
Another advantage of the present invention is that dampening means for the print elements are provided which are inexpensive both in terms of the cost of the parts and in terms of the cost of assembly.
It is accordingly an object of the present invention to provide a print head including elongated printing elements having an internal fixed vibration dampening means for the printing elements which is both inexpensive and effective in operation.
Another object is to provide a print head having elongated printing elements and also having vibration dampening means which does not impose a frictional load on the print elements during their normal operation.
A further object is to provide a print head which is durable and reliable in operation.
With these and other objects, which will become apparent from the following description, in view, the invention includes certain novel features of construction and combinations of parts, one form or embodiment of which is hereinafter described with reference to the drawings which accompany and form a part of this specification.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view, taken along line 1--1 of FIG. 2, of one embodiment of a print head in accordance with the present invention;
FIG. 2 is a cross-sectional view, taken along line 2--2 of FIG. 1;
FIG. 3 is an exploded elevation view, partly broken away, showing the frame, the elongated printing elements, and the dampening means, of the embodiment of FIG. 1 of the print head;
FIG. 4 is an enlarged end view, taken along line 4--4 of FIG. 3;
FIG. 5 is a cross-sectional view, taken along line 5--5 of FIG. 3;
FIG. 6 is a cross-sectional view, taken along line 6--6 of FIG. 3;
FIG. 7 is an elevation view, partly broken away, showing the frame, the elongated printing elements, and the dampening means, of a second embodiment of the invention; and
FIG. 8 is a cross-sectional view, taken along line 8--8 of FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now particularly to FIGS. 1 and 2 of the drawings, a print head 10 of the wire matrix type is shown. This print head is similar in general configuration to the print head disclosed in U.S. Pat. No. 3,929,214, issued Dec. 30, 1975, to which reference may be had for a more detailed description of certain aspects of the print head structure.
A frame 12 is provided to support a plurality of elongated print elements or print wires 14, only two of which are shown, for purposes of simplification and ready understanding of the drawings. Each wire 14 has a cap 16, which may be made of plastic or other suitable material, attached to its impact-receiving end to enlarge the area of the impact-receiving surface. Each wire 14 also has a spring 18 disposed at its upper end, which exerts an upward force upon the cap 16 to resiliently bias the wire upwardly, as shown in FIGS. 1 and 3, relative to the frame 12. The spring 18 has been omitted from one of the wires of FIG. 1, in order that the cap 16 may be more clearly depicted.
The frame 12 includes three side walls 20, 22, and 24, a print end support member 26, two intermediate support members 28 and 30 positioned in grooves in the side walls 20 and 22, and an upper end support member 32 which is formed integral with the side walls 20, 22 and 24 of the frame 12. The members 26, 28, 30 and 32 constrain the various print wires 14 in predetermined paths, and accomplish the translation of the wires from a circular formation at the upper end as seen in FIG. 1 to a linear formation at the printing end. The translation is accomplished by passing each wire 14 through a separate hole 34 in the upper member 32, through similar holes in the members 24 and 22, and into a defined position within a bearing 36 in the print end support member 26, as shown in FIG. 4. The bearing 36 is of a material which resists wear and has a low co-efficient of friction.
A pair of mounting flanges 38 and 40 extend laterally from the upper ends of side walls 20 and 22. The frame 12 is circular in cross-sectional shape above the flanges 38, 40 as seen in FIG. 1, and terminates in the upper end support member 32, which is of circular cconfiguration. An apertured post 42 extends from the member 32 and provides means for assembling the driving means for the wires 14 to the frame 12, as will subsequently be described in greater detail.
As shown in FIGS. 1 and 2, a plate 44 is provided with a central aperture 46 and is secured to the flanges 38, 40 on the frame 12 by suitable fastening means 48. The circular portion of the frame 12 extends through the aperture 46. A plurality of holes 50 are provided in the plate 44 for mounting a corresponding plurality, nine in the illustrated embodiment, of actuating means for the wire printing elements 14.
A coil 52, a center pole 54, an "L" shaped outer pole 56 and an armature 58 form the electromagnetic actuating means used in the print head. An armature shim 59 spaces the armatures 58 away from the poles 54 for the purpose of effecting faster armature release.
A unitary connector 62 is mounted by means of a screw 64 and a washer 66 to the post 42 of the frame 12. The connector 62 has a circular central portion 68 with an annular groove 70 provided in its bottom surface. An O-ring 72 is inserted in the groove 70 to act as a shock absorber and to provide a reference surface for the cap 16 of the print wire 14 striking the end of the armature 58. Nine arms 74 are formed integral with the central portion 68 of the connector 62 and extend therefrom. Each arm 74 has associated with it a first armature receiving structure 76 and a second armature receiving structure 78. One end of each armature 58 is received and held in place by the structure 76 and the other end of each armature is received and guided by the structure 78. With the connector 62 installed in the position shown, the arms 74 apply forces to the cantilevered distal ends of the armatures, causing their print wire impacting ends to rotate about the fulcrum formed by the top edge of the pole 56 and upwardly into engagement with the O-ring 72. The caps 16 associated with the print wires 14 are maintained in contact with the ends of the armature 58 by means of the forces applied by the springs 18.
As discussed in greater detail in the previously-cited U.S. Pat. No. 3,929,214, the unitary connector 62 serves a number of functions in the assembly and operation of the print head 10, including retaining the armatures 58 in proper relationship to the remainder of the structure, acting as a biasing means for the armatures, providing means for adjusting the air gap between the armatures 58 and corresponding center poles 52, forming a reference surface for the armatures 58 and print wire caps 16, to assure that all actuated print wires 14 impact the record medium at substantially the same time during a printing cycle, and, by means of the O-ring 72, absorbing energy from the armatures 58 and the print wires 14 on return motion after actuation.
As is also described in greater detail in the previously mentioned U.S. Pat. No. 3,929,214, characters such as numbers, letters or symbols are generated by the print head by a sequence of print cycles. Selective actuation of predetermined combinations of print wires 14 through energization of their corresponding coils 52 during each cycle results in the formation of the desired character on the record medium, with the print head being shifted one position with respect to the record medium after each cycle to be properly located for the next printing cycle.
When a coil 52 is energized, a magnetic flux is created which causes armature 58 to be drawn into contact with center pole 54. The movement of armature 58 transmits energy into print wire 14, causing it to move in an axial direction in the frame 12. The force imparted into the wire 14 causes it to move against the spring 18 and its inertia causes it to continue to move downwardly with the armature 58. The impact-delivering end of the print wire 14 extends beyond bearing 36 and strikes the record medium, causing a dot to be imprinted. The energy stored in the moving print wire 14 and armature 58 is partially absorbed by the impacted record medium and partially returned to the print wire 14, aiding the spring 18 in returning the print wire 14 to its rest position.
At approximately the same time that the print wire 14 is impacting the record medium, the coil 52 is deenergized. The moment exerted on the armature 58 by the arm 74 causes it to rotate away from the center pole 54 and to return into contact with the O-ring 72.
The structure which has been described to this point is conventional and provides an operable print head of the wire matrix type. However extended use of print heads of this type has resulted in problems of breakage of print wires 14 and springs 18 by fatigue failure.
The print wires 14 are small in diameter in order to produce proper character line width, a typical diameter being 0.014 inches. Print wire length is relatively long (typically 3 inches), in order to enable the print wires to be fanned out from their tight linear pattern at the bearing 36 to the larger circular pattern required to coact with the armatures 58. Due to the large ratio of wire length to wire diameter, and the fact that a relatively large impact force (approximately 4.5 pounds) is required to print, the wire 14 has a tendency to buckle. This tendency can be reduced by the addition of transverse supporting members along the length of the wire. As has been previously noted, some matrix print heads also employ anchored tubes or coil springs as supports, in order to further reduce the likelihood of buckling of the print wire.
In the present structure, a series of simple supports 28, 30 and 32 are spaced at intervals along the wire. However wire buckling still tends to take place between the supports. It is believed that a major cause of fatigue failure of print wires is radial oscillation of the wire caused by buckling under printing impact. After the initial buckling takes place, the frequency of the oscillation is dependent upon the natural frequency of the wire between the supports. The amplitude of this oscillation is, from time to time, increased by constructive interference of the wave motion supplied by subsequent impacts. When this occurs, the stress in the wire exceeds the endurance limit of the material.
The present invention reduces wire radial motion by adding a centrally disposed dampening means or internal mode changer 84.
As shown in FIGS. 1 to 6 inclusive, in one embodiment of the invention, the internal mode changer 84 is formed in two portions 86 and 88. The portion 86 is formed integrally with the intermediate support member 30, while the portion 88 is a separate element which is joined to the combination of the portion 86 and support member 30 by any suitable means, such as a snap fit. The effect is to provide a centrally disposed mode changer 84 which is positioned within the array of print wires 14, and which is connected to the frame 12 only by the support member 30. The mounting of the mode changer 84, which is relatively long with respect to its cross-sectional dimensions, to the frame at a location which is intermediate of the ends of the mode changer contributes to its stability and minimizes any tendency toward vibration of the smaller end portion thereof in response to action of the wires thereon.
It will be noted that the surface of the mode changer 84 is of the same general contour as a surface which includes the array of print wires 14, and that each individual print wire 14 is spaced substantially the same distance as the remaining wires from the surface of the mode changer 84. It will further be noted that the cross section of the mode changer 84 varies from a larger oval configuration at the end closest to the support member 32, as shown in FIG. 5, to a smaller oval shape at the end which is closest to the support member 28, as shown in FIG. 6. This corresponds to the wire array which is arranged in an oval configuration near the support member 32, in conformity to the circular arrangement of the coils 52, and which is guided by the support members 32, 30, 28 and 26 to a linear alignment at the printing end of the print head, as shown in FIG. 4.
A second embodiment of the invention is shown in FIGS. 7 and 8. This embodiment is quite similar to the embodiment of FIGS. 1 to 6 inclusive, except that an internal mode changer 90, while of the same general configuration, is connected to the frame 12 in a different manner. A first portion 92 of the mode changer 90 is formed integral with the support member 30 in the same manner as in the first embodiment. However a second portion 94, instead of being attached to the combined support member 30 and first portion 92, is formed integral with the support member 32. Here again the design avoids stability problems which might be found if the relatively long mode changer 90 were fixed to the frame only at its large end. Other means of securing portions of the mode changer to one or more support members of the frame in accordance with the above teaching will suggest themselves to those skilled in the art.
The purpose of the mode changer, in either embodiment, is two-fold. First, by its close proximity to the printing wires 14, it prevents an excessive radial excursion of the wires during printing movement, due to initial buckling, and second, by this same restraint it prevents the printing wires 14 from oscillating at their natural frequency. It will be noted that the internal mode changer 84 or 90 is held stationary inside the array of print wires 14, so that the wires do not contact the mode changer until after they buckle. Therefore no frictional drag or extra mass is added to the print wires on their flight toward the impacct surface.
While the forms of the invention shown and described herein are admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the forms or embodiments disclosed herein, for it is susceptible of embodiment in various other forms within the scope of the appended claims.
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In a matrix print head, a plurality of elongated printing elements, mounted in a frame, are driven axially by electromagnetic means to effect printing on record media positioned adjacent to the printing ends of the printing elements. A dampening element, of generally conical configuration, is centrally disposed in the frame, within the volume defined by the plurality of printing elements, in order to dampen the bending and vibration of the printing elements, and thus reduce or eliminate consequent fatigue failure.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the design of an improved delivery apparatus for applying two component fibrinogen/thrombin tissue sealants. More particularly, this invention is directed to the design of an apparatus that is easy to use and to fill, that allows accurate dispensing of small volumes and rapid dispensing of large volumes of tissue sealant, that allows minimal dilution of the fibrinogen component, and that ensures thorough mixing of the two sealant components, thus promoting rapid coagulation with a minimal amount of thrombin to produce a homogeneous tissue sealant.
2. Discussion of the Background
Clotting of blood in vivo takes place by conversion of the soluble plasma protein fibrinogen into fibrin, which spontaneously polymerizes into an insoluble gel matrix which may attach to adjacent tissue. The gel matrix stops bleeding and stabilizes structures. Thrombin catalyzed conversion of fibrinogen to fibrin can be reproduced in vitro and has great utility for adhering tissues and achieving hemostasis. Such fibrin sealants and fibrin glues are available commercially and are also made in blood processing laboratories. Preparation and use of fibrinogen-based sealants have been extensively reviewed 1 .
Fibrin sealants, fibrin glues and adhesives based on combining fibrinogen-containing solutions with thrombin-containing solutions are used to reduce bleeding and restore hemostasis during surgical procedures. They have been known and in use for many years during which technology has evolved significantly. For example, fibrin clots can be made using different concentrations of fibrinogen in conjunction with the thrombin solution 2 . Subsequent developments in technology include cryoprecipitate fibrinogen 3 . Concentrated plasma can be used as the fibrinogen component in fibrin sealants 4 .
Similarly, various types of applicators for fibrin glue are known 5 . An optimal design is not obvious because of the chemical and biological properties of the liquid resulting from combining fibrinogen and thrombin solutions. Because of the rapid polymerization upon intimate interaction of fibrinogen and thrombin, it is important to keep separate these two blood proteins until application to the site of use. In practice, the two components are typically dispensed simultaneously from separate syringes and brought together by means of an applicator manifold.
For example, one syringe-type apparatus for applying a tissue adhesive includes a plurality of standardized one-way syringe bodies of synthetic material 6 . Each syringe body accommodates a plunger and ends in a conus. The apparatus also includes a means for holding together the various syringe bodies, a guide rod, common actuating means and a head collecting the coni of said syringe bodies. This design, however, does not appear prevent clogging when flow of materials is interrupted during the course of its use in applying these materials to a surface. The connecting head brings the two materials together and the materials then travel together to a single mixing needle. Because of the rapid coagulation of the materials on mixing, this arrangement facilitates clogging of the apparatus (and in particular, the head or manifold), thus rendering the apparatus unusable.
In a later design, a medicinal gas is used to clear the mixing needle and address the clogging problem 7 . It is acknowledged that the tissue adhesive may set in the mixing needle in case of an interruption of the flow of the components during application or when using long and thin mixing needles. Consequently, the mixing needle must be exchanged immediately (e.g., upon interruption of use). However, from a practical perspective, the use of a medicinal gas is not suitable for most situations.
Similar arrangements/designs may be subject to the same deficiency, clogging. One design makes use of a ribbon-like separation means to confine clogging to a disposable tip 8 . Another design has the useful feature of specifying that the two syringes have different cross sections 9 . This arrangement includes a plurality of syringe bodies having equal effective strokes, each of the syringe bodies ending in joining pieces; a piston in each syringe body for commonly actuating them; and a connecting head attached to the joining pieces of the syringe bodies and provided with a separate conveying channel for each of the components to be applied. In this design, one of said syringe bodies has a cross-sectional area that is two to nine times larger than the cross-sectional area of the remaining syringe bodies. The larger syringe body contains an adhesive protein solution having a fibrinogen content of from 3 to 12%.
One reason for this arrangement/design is that the strength of the sealant is proportional to the fibrinogen concentration. Further, since cryoprecipitate fibrinogen is not very soluble a smaller volume of thrombin solution is useful in making a gel with greater adhesive and tensile strength.
An alternative embodiment that may help to minimize the clogging problem arranges for the two components to meet and mix within a disposable mixing tip 10 . This apparatus includes a plurality of distinct, elongate chambers containing fluids, each chamber including a piston for forcibly ejecting the fluid therefrom through a tapered nozzle; needle means having a corresponding plurality of interior conduits for dispensing fluid from said nozzles; lock means including a ridge projecting about an exterior surface of each tapered nozzle; and releasable retaining means comprising a separable needle and a releasable retaining means comprising a separable needle block having a fluid conduit with an interior groove for engaging a corresponding nozzle ridge and means for retaining associated needle means in sealing relationship with the chamber nozzles and the fluid conduits.
The apparatus, however, may be inappropriate for use in delicate microsurgical applications. Separation of the two components in separate channels in the mixing tip is effective but not optimal.
It is known that the tensile and adhesive strengths of fibrin sealants are best if the two solutions are mixed well, preferably rapidly to homogeneity 11 . One apparatus which addresses the clogging problem prevents commingling of the two sealant components until they reach the treatment site 12 . This apparatus, however, may not provide thorough and adequate mixing of the two solutions. The same limitation is found in an endoscope design 13 .
Moreover, all of the heretofore referenced patents similarly fail to effectively address the issue of providing for thorough mixing of the sealant components during application, particularly if the apparatus is designed to overcome the clogging problem. This has two undesirable consequences: (1) the resultant gel is inhomogeneous and not as strong as that resulting from homogeneously mixed solutions and (2) more thrombin may be required to ensure rapid gelling. Risks associated with use of bovine thrombin make it undesirable to use excessive amounts. The U. S. Food and Drug Administration has expressed concern over coagulopathies associated with immunological reactions to commonly used bovine thrombin preparations 14 . The risk of zoonotic disease transmission has prompted the United Kingdom, Ireland and France to ban the use of bovine thrombin.
A method for conversion of autologous fibrinogen to non-cross-linked fibrin II or incomplete fibrinogen cleavage products (fibrin I or des BB fibrin, having one or the other of the two fibrinopeptides intact) using an insolubilized enzyme addresses a need for a thrombin-free fibrin glue 15 . The resulting unstabilized gel is dissolved by pH adjustment, separated from the insolublized enzyme, then mixed with buffer to restore conditions favorable to the repolymerization of the solubilized fibrin monomer solution, thus avoiding the addition of any soluble foreign animal protein (thrombin) to effect gelation of the sealant. A similar single protein solution method uses a mixture of thrombin and fibrinogen with an agent that inhibits the clotting activity of thrombin 16 .
Limitations of these two methods include their multi-step nature and the consequent expense and time required to carry out the processes. Additionally, the molecular structure and physical and adhesive properties of the resultant gels are not likely to be equivalent to those of naturally formed clots 7 .
Yet another limitation of previous applicator designs is that depressing syringe plungers may render accurate dispensing of small volumes of sealant (e. g., single drops) difficult. Proposed solutions to this difficulty include a dispenser with a push button actuator 18 and a device using a lever and ratchet and pawl mechanism 19 to dispense sealant components by pressure so that small volumes can be dispensed during delicate operations such as otological surgical procedures. Both of these devices are limited by the inability to rapidly dispense larger volumes of sealant when required, thus falling short of practical volume flexibility needs.
The use of unequal amounts of solutions within the syringe bodies dispensed simultaneously advantageously allows for minimizing dilution of the fibrinogen containing solution by the thrombin solution. However, filling the separate compartments with the respective sealant components and assembling the mechanical components comprising these devices can be complicated and time consuming.
One applicator, designed to produce a mist of mixed components 20 , is similarly complicated to assemble and use. If care is not taken in assembly of the device, misalignment of the two syringes with respect to the applicator device and incomplete sealing of the syringe Luer ports into the docking ports of the applicator manifolds may occur. In addition, mixing takes place in a spray head which may clog after use.
Alternatively, the two components of a fibrinogen-based tissue sealant may be applied as separate aerosols and mixed in the field 21 ,22. These devices may not allow for adequate mixing of the two sealant components, Consequently, greater amounts of thrombin and inferior gels may be produced, a problem inherent in field mixing.
REFERENCES
The following references are incorporated herein by reference, in their entireties or to any extent desired and/or necessary.
1. Matras, H. (1985). "Fibrin seal: the state of the art." J Oral Maxillofac Surg 43(8): 605-11.
Sierra, D. H. (1993). "Fibrin sealant adhesive systems: a review of their chemistry, material properties and clinical applications." J Biomater Appl 7(4): 309-52.
Thompson, D. F., N. A. Letassy, et al. (1988). "Fibrin glue: a review of its preparation, efficacy, and adverse effects as a topical hemostat." Drug Intell Clin Pharm 22(12): 946-52.
2. Ferry, J. D. and P. R. Morrison (1950). "Fibrin clots and methods for preparing the same." U.S. Pat. No. 2,553,004.
3. Alterbaum, R. (1987). "Method and apparatus for use in preparation of fibrinogen from a patient's blood." U.S. Pat. No. 4,714,457.
Lontz, J. F. (1995). "Phase Transfer Process For Producing Native Plasma Protein Concentrates." U.S. Pat. No. 5,420,250.
Matras, H., H. P. Dinges, et al. (1972). "Zur nahtlosen interfaszikularen Nerventransplantation im Tierexperiment." Wein Med Woschtr 122(37): 517-523.
Rose, E. and A. Dresdale (1986). "Fibrin adhesive prepared as a concentrate from single donor fresh frozen plasma." U.S. Pat. No. 4,627,879.
4. Antanavich, R. and R. Dorian (1995). "Plasma concentrate and tissue sealant compositions . . . ." U.S. patent application Ser. No. 08/351,010.
5. See Section 4, pages 320-321, in Sierra, D. H. (1993). "Fibrin sealant adhesive systems: a review of their chemistry, material properties and clinical applications." J Biomater Appl 7(4): 309-52.
6. Redl, H. and G. Kriwetz (1982). "Apparatus for applying a tissue adhesive on the basis of human or animal proteins." U.S. Pat. No. 4,359,049.
7. Redl, H. and G. Habison (1986). "Apparatus for Applying a tissue adhesive." U.S. Pat. No. 4,631,055.
8. Keller, W. A. and S. A. Chen (1988). "Dispensing and mixing apparatus." U.S. Pat. No. 4,767,026.
9. Eibl, J., G. Hobbesian, et al. (1988). "Arrangement for applying a tissue adhesive." U.S. Pat. No. 4,735,616.
10. Speer, S. J. (1977). "Packaging and dispensing kit." U.S. Pat. No. 4,040,420.
11. Thompson, D. F., N. A. Letassy, et al. (1988). "Fibrin glue: a review of its preparation, efficacy, and adverse effects as a topical hemostat." Drug Intell Clin Pharm 22(12): 946-52. See paragraph pp. 948-9.
Redl, H., G. Schlag, et al. (1982). "Methods of Fibrin Seal Application." Thorac. cardiovasc. Surgeon 30: 223-227.
Redl, H. and G. Schlag (1986). Fibrin Sealant and Its Modes of Application. Fibrin Sealant in Operative Medicine. G. Schlad and H. Redl. Heidelberg, Springer-Verlag: 13-26.
Shimada, J., K. Mikami, et al. (1995). "Closure of leaks by fibrin gluing. Effects of various application techniques and temperatures." J Cardiovasc Surg (Torino) 36(2): 181-4.
12. Miller, C. H., J. H. Altshuler, et al. (1989). "Fibrin glue delivery system." U.S. Pat. No. 4,874,368.
13. Maslanka, H. (1990). "Injection equipment with a twin tubular needle for an endoscope." U.S. Pat. No. 4,932,942.
14. Alving, B. M., M. J. Weinstein, et al. (1995). "Fibrin sealant: summary of a conference on characteristics and clinical uses." Transfusion 35(9): 783-90.
15. Edwardson, P. A. D., J. E. Fairbrother, et al. (1993). "Fibrin sealant compositions and method for utilizing same." EP (Application) Patent 592,242.
16. Morse, B. S., R. T. McNally, et al. (1994). "Fibrin sealant delivery kit." U.S. Pat. No. 5,318,524.
17. Sporn, L. A., L. A. Bunce, et al. (1995). "Cell proliferation on fibrin: modulation by fibrinopeptide cleavage." Blood 86(5): 1802-10.
18. Tang, R. A. (1986). A New Application Method for Fibrin Sealant: The Glue Gun. Fibrin Sealant in Operative Medicine. G. Schlad and H. Redl. Heidelberg, Springer-Verlag.
19. Epstein, G. H. (1993). "Method and apparatus for preparing fibrinogen adhesive from whole blood." U.S. Pat. No. 5,226,877.
20. Capozzi, E., and H. S. Cooksten (1992). "Biological syringe system." U.S. Pat. No. 5,116,315.
Capozzi, E., and H. S. Cooksten (1990). "Biological syringe system." U.S. Pat. No. 4,978,336.
21. Avoy, D. R. (1990). "Fibrinogen dispensing kit." U.S. Pat. No. 4,902,281.
22. Lonneman, A. and C. H. Miller (1994). "Sprayer assembly for physiologic glue." U.S. Pat. No. 5,368,563.
OBJECTS OF THE INVENTION
The present invention disclosed herein addresses and solves the limitation of the prior devices. The present applicator is easy to assemble, can accurately dispense small volumes or rapidly dispense large volumes of sealant, minimizes dilution of the fibrinogen component, adequately mixes the two components, does not clog event when set aside for several minutes, and is relatively easy to fill, assemble, use and manufacture.
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 shows an embodiment of the present invention employing two syringes 1 and 8 affixed in a bracket 2 with rack and pinion drive 3, manifold 4 and optional replaceable applicator static mixing tip 5. Syringes 1 and 8 are affixed to bracket 2. Syringe plungers 6 and 9 are depressed by movement of the rack 7.
FIG. 2 shows a side view of and embodiment of the bracket 2 and rack and pinion drive 3. Syringes 1 and 8 are affixed to bracket 2. Rack 3 can be depressed directly to rapidly dispense larger volumes of sealant, or the thumb wheel pinion 14 can be turned to displace small volumes accurately. Syringe plungers are depressed by movement of the rack.
FIGS. 3A, 3B and 3C show cross sections of three arrangements for the separate compartments for containing and dispensing the separate fibrinogen and gel-forming agent solutions: FIG. 3A shows syringes 1 and 8 held together side-by-side in a bracket as shown in FIGS. 1 and 2; FIG. 3B shows integral side-by-side cylinders 15, made from a single mold; FIG. 3C shows and embodiment comprising coaxially arranged cylinders 10 and 11. The fibrinogen solution is put in the compartment with the larger cross section 12 and the thrombin and/or calcium solution is put in the compartment with the smaller cross section 13.
FIG. 4 is a cross-sectional view of an embodiment of the manifold 4 and applicator static mixer tip 5 of the syringe of FIG. 1. Swivel Luer locks 21 provide a means for attaching the syringes. Thrombin is dispensed through the inner needle 22 and fibrinogen through the void 23 between inner needle 22 and outer sleeve 25. Inserted static mixer device 26 fits snugly within the outer sleeve 25. Notched rings 28 on the rod mixer device ensure mixing of the two sealant components by creating turbulent flow. The distal tip 24 of the inner needle is located within the outer sleeve near the mixing device insert 26.
FIG. 5 shows a cross-sectional view of coaxially arranged cylindrical compartments as shown in FIG. 3C. The inner syringe 32 containing thrombin solution is coaxial with the large syringe 31 containing fibrinogen solution. The inner syringe plunger 34 operates normally, traveling through a hole or slot in the plunger for the outer compartment 35. The cylinders are maintained coaxial with a cylindrical washer 38 made of rubber of other suitable material. The needle 37 leading from the inner compartment 40 conducts the thrombin into the replaceable mixing tip 39.
FIG. 6 is a detailed cross-sectional view of the lower part of the coaxial syringe shown in FIG. 5. The mixing tip is removed. The needle 37 leading from the inner compartment 40 exits through the center of a male Luer lock 42. The fibrinogen solution in the outer compartment is conducted through a channel 41 in the washer 38 and exits from the male Luer lock around the inner chamber needle 37.
FIG. 7 is a cross-sectional view of an embodiment of a filling device (a "connecting tee") used to fill the two compartments of the coaxial syringe shown in FIG. 5. A female Luer lock 53 is joined with the male on the syringe 42. The needle 37 from the inner chamber 40 pierces a rubber septum 52. The inner needle tip 39 may then be used to fill the inner compartment (e.g. by piercing a septum on a container containing the gel-forming agent solution). The outer compartment may then be filled with fibrinogen solution by fluidly connecting a chamber containing fibrinogen solution to a male Luer lock 51.
FIGS. 8, 9, 10 and 11 each show cross-sectional views of various embodiments of the manifolds and mixing tips of the present apparatus for applying tissue sealant. In all cases, the coaxial syringe shown in FIG. 5 is used. A Luer lock 42 is used to attach each of the four applicator tips to the double syringe.
FIG. 8 shows a disposable static mixer tip 26 essentially identical to the one in FIG. 4.
FIG. 9 shows a flexible double lumen catheter 62 for application of tissue sealant at a distance from the syringe, (e.g., in a body cavity made accessible by laparotomy). The Luer lock 61 allows attachment of the double lumen catheter 62 to the syringe, permitting separation of the solutions as they travel through the catheter 62. The catheter ends with a disposable static mixer tip 26 essentially identical to the one in FIG. 4.
FIG. 10 shows a spray tip 71. The two components mix in the tip 71 and the mixture is nebulized by a small orifice 72.
FIG. 11 shows a simple mixing needle tip 81 that does not clog, even if one intermittently applies sealant using the same applicator and component solutions.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention concerns, in part, a dispenser comprising:
a plurality of separate parallel cylindrical compartments of the same or different cross sectional area, arranged concentrically or side-by-side, each of said cylindrical compartments having an outlet port at one end,
a number of plungers equal to said plurality of cylindrical compartments, and
a manifold having separate means for transporting fluid through the manifold from the outlet port of each cylindrical compartment to a common location on the surface of the manifold opposite said outlet ports.
In further embodiments, the dispenser may further comprise a means for separately or commonly actuating said plungers in mechanical connection to said plungers, preferably both a means for commonly actuating said plungers and a means for separately actuating said plungers. The means for commonly actuating said plungers may comprise a rack and pinion mechanism. Alternatively, the means for commonly actuating said plungers comprises a bar, rod or other means for mechanically connecting said pinion to the cap of each plunger.
The cylindrical compartments of the dispenser may be coaxial, and said means for commonly actuating said plungers and said means for separately actuating said plungers may comprise a coaxial inner plunger having a cap and a coaxial outer plunger having a coaxial cylindrical void into which said inner plunger is located, the diameter of said cap being greater than the diameter of said cylindrical void. In other words, the cylindrical compartments may comprise inner and outer concentric compartments, the inner concentric cylindrical compartment being fitted with an inner plunger, and the outer concentric compartment being fitted with a cylindrical plunger having a coaxial cylindrical void within which said inner plunger is located.
In one embodiment, the present dispenser comprises two coaxial cylinders of different sizes. When the plurality of cylinders is 2, said cylinders may have equal heights, and the volume ratio of said cylinders may be 9 or more, preferably 10 or greater. In the present application, "coaxial cylinders" refers to cylinders which share a common axis, or parallel cylinders of different diameters in which the void of the smaller cylinder is contained within the larger cylinder.
The present dispenser may further comprise a manifold comprising separate inner and outer means for conveying the contents of said cylinders to a common outlet, wherein the inner means extends further than the outer means. The present dispenser may also further comprise a disposable tip which promotes mixing of said contents of the cylinders. In addition, the present dispenser may further comprising a means for atomizing effluent fluid in fluid connection to one end of said cylindrical fluid conduit.
Fibrinogen and thrombin solutions are contained separately within compartments in an apparatus comprising: (1) syringes held together side-by-side in a bracket, the plungers of said syringes commonly actuable or depressible by an activating means or (2) integral side-by-side cylinders fitted with coupled plungers for simultaneously expressing or dispensing the contents of said cylinders or, preferably, (3) coaxially arranged cylinders fitted with commonly (or separably) depressible or actuable plungers, the outermost of which is shaped to seal against both the inner wall of the outer cylinder and the outer wall of the inner cylinder.
Other factors being constant, tensile and adhesive strengths of tissue sealant are generally proportional to the concentration of fibrinogen after combination with thrombin. To minimize dilution of fibrinogen by the thrombin solution, the cross-sectional areas of the two compartments are preferably different so that a common stroke will displace a small amount of thrombin solution relative to fibrinogen solution. Any ratio of cross-sectional areas is workable. A ratio of cross-sectional areas of greater than 1:5 is preferable and a ratio of 1:10 up to 1:40 is most preferable.
The volume of the compartments may vary depending on the intended use. Tissue sealants are typically dispensed from fibrinogen preparations of volume ranging from 0.5 cc to 5 cc. As described above, the corresponding thrombin compartment typically would have a volume of one tenth to one fortieth the volume of the fibrinogen compartment.
In the embodiments of the present apparatus comprising side-by-side syringes or cylinders, to facilitate assembly, convenient fittings such as swivel Luer lock fittings or the like are provided for coupling to a manifold so that coupling can be effected without the necessity of rotating the syringes or cylinders relative to the assembly fixture and manifold. Alternatively, the two syringes or cylinders terminate in needles which may serve the dual functions of (1) facilitating filling with appropriate components of the fibrin sealant and (2) connecting to a manifold fitted with septa to mate with the needles, allowing fluid communication between the respective compartments and appropriate channels within the manifold.
A further aspect of the present invention concerns a manifold for combining the contents of a multicomponent dispenser, comprising
a first inlet port,
an inner fluid transport means in fluid connection with said first inlet port, said inner fluid transport means having a first outlet port located at the end opposite said first inlet port,
a second inlet port distinct from the first inlet port, and
an outer fluid transport means in fluid communication with said second inlet port, said outer fluid transport means having a second fluid outlet port located at the end opposite said second inlet port,
wherein said second fluid outlet port is in the same location as said first outlet port and at least part of said inner fluid transport means is located within said outer fluid transport means.
In more specific embodiments of the manifold, the inner fluid transport means and said first inlet port comprise a hypodermic needle, and said second inlet port and said outer fluid transport means comprises a channel in a solid material through which said hypodermic needle is located or is able to penetrate (see FIG. 4).
In order to minimize the problem of plugging due to coagulation of sealant within the manifold, the manifold is configured in such a way as to prevent commingling of the two sealant components until the expression of one component, through a needle or the like which separately conducts said component, into a flow of the second component within a sleeve, e.g. a larger bore hypodermic needle or the like, which surrounds said first hypodermic needle, the outer sleeve terminating at a point distal to the point at which commingling of the two fluids first occurs.
The needle conducting the lower-volume (e.g., thrombin) solution may be a standard 22 gauge needle, and the larger bore needle conducting the higher-volume (e.g., fibrinogen) solution may be a standard 18 gauge needle. The larger needle may be of any size from 3 to 25 gauge, and from 0.5 cm to 6 cm in length, preferably 1 to 3 cm. The smaller needle must fit within the larger and not obstruct flow.
In a further embodiment of the present apparatus comprising coaxially arranged cylinders, the contents of the inner compartment are in fluid communication with a hypodermic needle or the like which extends beyond the distal terminus of a coaxial effluent port of the outer compartment and which is of an outer diameter less than the inner diameter of said effluent port. The contents of said outer compartment are isolated from those of the inner compartment, but are in fluid communication with the effluent port of the outer compartment. By means of a Luer fitting or the like, an outer sleeve comprising a hypodermic needle or the like, of greater internal diameter than the outer diameter of the inner hypodermic needle described above, is affixed to the effluent port of the outer compartment. The outer sleeve extends beyond the distal terminus of the inner hypodermic needle. The volume of the compartments may vary depending on the intended use. Tissue sealants are typically dispensed from fibrinogen preparations of volume ranging from 0.5 cc to 5 cc. As described above, the corresponding thrombin compartment typically would have a volume of one tenth to one fortieth.
By commonly depressing the respective plungers of the inner and outer compartments, the contents of the separate compartments are expressed, dispensed or exhausted separately but simultaneously through the inner hypodermic needle and the outer sleeve. As they are expressed, the two separate fluid components merge at the distal terminus of the inner hypodermic needle within the outer sleeve. The merged fluids commingle and become mixed as they flow within the outer sleeve towards the distal terminus, becoming more thoroughly mixed by the time they are applied to the site of use. If flow is interrupted during sealant dispensing , a gel may form in the outer sleeve at a location between the distal terminus of the inner hypodermic needle to the distal terminus of the outer sleeve. The gel typically forms a short cylinder in the void within the outer sleeve and does not substantially adhere to the material of the outer sleeve or inner needle. Rather, the short gel cylinder extends from the distal terminus of the inner needle toward the distal terminus of the outer sleeve. Because of its shape, small size and lack of adherence to the surrounding outer sleeve, the gel which may form does not effectively plug the device and can be dispensed or expressed by resuming application of sealant without exerting perceptibly greater force to depress the commonly actuated plungers.
Mixing of the two fluid components as they are extruded is adequate for most applications, yielding strong gels which rapidly polymerize at low thrombin concentrations. optionally, if perfectly homogeneous mixing of the two fluid components is desirable, the outer sleeve may incorporate a static mixer comprising, for example, of parallel arcs centered on the axis of a shaft snugly fitted to the inner wall of the outer sleeve from a point just distal to the distal terminus of the inner hypodermic needle and extending to a point proximal to the distal terminus of the outer sleeve. Thus, the present invention also concerns a static mixing means, comprising:
a cylindrical fluid conduit,
a coaxial shaft having parallel arcs thereon, fitted within said cylindrical fluid conduit, wherein said parallel arcs promote mixing of said fluid.
Adjacent arcs may be rotated about the axis of the cylinder to force a more tortuous and turbulent flow of the commingled fluids. Preferably, the arcs are positioned along the mixing tip so that the gaps of the rings are located opposite the gaps of the adjacent rings. Most preferably, the gaps on adjacent rings are on opposite sides. The static mixing insert may be of any length from 0.1 cm to 5 cm, preferably 0.25 to 1 cm. The number of arcs may range from two to fifty, preferably five to fifteen. Thus, each arc of the present mixing means may comprise a ring having a void of from 5° to 90°, the void of one ring being located opposite the void on adjacent ring(s).
On interruption of flow, coagulation of the sealant about the static mixer will occlude the flow path. Removing and replacing the outer sleeve and static mixer may be necessary in this embodiment. However, the combination of the outer sleeve and static mixer is inexpensive, and the method of removing and replacing this combination is a very simple operation which sacrifices a minute included volume of sealant and is completely effective in restoring functionality of the applicator device.
Prior to dispensing sealant as variously described above, the separate fibrinogen solution and thrombin or other clot-promoting solutions must be charged into the respective applicator compartments. For this purpose, a connecting tee can be used to direct the flow of the two solutions separately into the appropriate compartments.
Thus, a further aspect of the present invention concerns a device for filling a two-compartment dispenser, comprising
a first means for fluidly connecting said device with an outlet port of a first container for fluid,
a first means for transporting fluid from said first means for fluidly connecting said device to a first compartment of said dispenser,
a second means for fluidly connecting said device to a second container for fluid,
a second means for transporting fluid through said device from said second means for fluidly connecting said device to an outlet port for the other of said two compartments of said dispenser.
A more specific embodiment of the device for filling the present dispenser may comprise
a cylindrical shaft having a Luer fitting at one end and a pierceable septum at the other end, and
a Luer fitting attached to the outer wall of said cylindrical shaft.
As shown in FIG. 7, the tee comprises a female Luer coupling 53 or equivalent means for docking with the effluent port 42 of the outer compartment. The inner hypodermic needle 37 is directed through this coupling and pierces a septum 52 which seals the opposing end of the tee so that said hypodermic needle passes in a straight path through the tee and isolates its contents from the void within the tee and is free beyond the tee to collect the appropriate solution. The tee must be short enough that the needle pierces the septum but should not have excessive volume. The length thus may be as little as 0.5 cm and may be as long as slightly shorter than the inner needle. Preferably, the tee is 1.5 to 3 cm in length.
The inner plunger is separably actuable from the outer plunger and is pulled back separately from the outer plunger to withdraw appropriate solution from a source into the inner compartment. The orthogonal arm of the tee can be fitted with a hypodermic needle or tubing or the like. By separately pulling back the outer plunger, the second sealant component is withdrawn from a source through said hypodermic needle or tubing or the like and into the outer compartment. Alternatively, both solutions can be separately and simultaneously introduced into the appropriate compartments by pulling back simultaneously on both plungers while the inner hypodermic needle and appropriate means for the orthogonal arm of the tee to communicate fluidly with an appropriate fluid component source are simultaneously in separate fluid communication with the respective sealant component sources. The plungers are so arranged that each may be separately pulled back or both together.
The inner and outer plungers are separably actuable by virtue of an arrangement whereby the inner plunger moves freely and independently within a hollow outer plunger (i.e., the outer plunger contains a cylindrical void within which the inner plunger is located). The top of the outer plunger may comprise a button with a center opening of sufficient diameter to allow the inner plunger to move freely. A button on the top of the inner plunger, however, which is larger than the opening in the top of the outer plunger button engages the two plungers to move in concert when the upper plunger is depressed and encounters the outer plunger button. In other words, the hole in the center of the outer plunger has a diameter smaller than the diameter of the inner plunger button (e.g., insufficient to allow the inner plunger button to travel further without simultaneously effecting an equal stroke of the outer plunger). The bases of the inner and outer cylinders are tapered in such a way as to conduct air entrapped within the two compartments to a high point communicating with the respective effluent channels when the apparatus is inverted, thus permitting entrapped air to be expelled after filling and before application of sealant to the site of use.
To permit accurately controlled dispensing of small volumes of sealant (e.g., single drops), depression of the commonly actuable plungers of any of the above described embodiments may be effected by a means for depressing the plungers (e.g., a rack and pinion mechanism driven, for example, by a thumb wheel pinion as shown in FIG. 2). When rapid dispensing of sealant is desired, said rack can be depressed directly. The rack and pinion may be used with any of the three cylinder arrangements previously described.
When a spray sealant is desired, any of the above described embodiments may further comprise an atomizing nozzle at the outlet port. Mixing occurs before atomization, assuring homogeneous sealant and the strongest gel while using a minimal amount of thrombin. However, interrupting sealant flow may lead to clogging the atomizing attachment and may thereby necessitate replacing the atomizing attachment.
Thus, either the present dispenser or the present mixing means may further comprise a means for atomizing effluent fluid in fluid connection to one end of said cylindrical fluid conduit in the means for applying the mixed fluids to the desired site of application.
A further aspect of the present invention concerns a method for applying two or more solutions of reactive components to a common site, comprising:
filling a first compartment of a multi-compartment applicator with a first reactant,
filling a second compartment of said multi-compartment applicator with a second reactant, said second reactant being capable of instantaneously reacting with said first component,
simultaneously dispensing the components of each of said compartments through a common location in a manifold into a mixing tip, from which the mixed components are applied to said site.
In the present method, the components may react to form a product selected from the group consisting of tissue sealant and epoxy glue. In a further embodiment, the compartments of said applicator have the same height but different cross-sectional areas, said components react to form tissue sealant and the compartment with larger cross section contains fibrin or fibrinogen solution. The applicator may have two compartments, and the compartment with smaller cross section may contain a thrombin solution.
Other features of the present invention will become apparent in the course of the following descriptions of the exemplary embodiments which are given for illustration of the invention, and are not intended to be limiting thereof.
EXPERIMENTS
Example 1
Plasma Gel Made with Mixing Needle
One cubic centimeter of 300 millimolar calcium chloride solution containing 100 units of bovine thrombin was loaded into the inner compartment of a coaxially arranged two compartment dispenser constructed according to the design illustrated in FIG. 5. Ten cubic centimeters of porcine plasma separated by centrifugation (1500×g for 15 minutes) from whole blood collected in standard citrate anticoagulant solution was loaded into the outer compartment. The cross-sectional area of the outer compartment was 14.3 times greater than that of the inner compartment. The two solutions were expressed by pressing the button in the center of the plungers and simultaneously depressing both plungers. The thrombin solution was extruded through a standard 22 gauge hypodermic needle housed within a standard 18 gauge hypodermic needle (which served as conduit for the expressed plasma) the arrangement shown in FIGS. 5 and 11. The two solutions merged within the outer needle approximately 1 cm from the tip of the outer needle. The sealant was extruded in this manner directly into cylindrical mold cavities of 9.3 mm diameter and approximately 5 cm length. Coagulation of the extruded fluid occurred within approximately 5 seconds. Approximately 5 minutes were allowed to elapse between filling each of three molds. No noticeable increase in force was required to begin dispensing sealant into the molds after these interruptions of flow. After 20 minutes incubation at room temperature to allow factor XIII mediated crosslinking of the molded gels, the gels were removed from their molds, clamped at either end and assembled into a device for measuring tensile strength. Tensile strength was found to be 66±12 (mean±standard deviation) grams per square centimeter.
Example 2
Plasma Gel Film Made with Nebulizer
One cubic centimeter of 300 millimolar calcium chloride solution containing 100 units of bovine thrombin was loaded into the inner compartment of a coaxially arranged two-compartment dispenser constructed per the design represented by the illustration of FIGS. 5 and 10. Ten cubic centimeters of porcine plasma separated by centrifugation (1500×g for 15 minutes) from whole blood collected in standard citrate anticoagulant solution was loaded into the outer compartment. The cross-sectional area of the outer compartment was 14.3 times greater than that of the inner compartment. The two solutions were dispensed by pressing the button in the center of the plungers and simultaneously depressing both plungers. The thrombin-calcium solution was dispensed through the nebulizer tip shown in FIG. 8. The two solutions merged within the tip and emerged as a fine spray which was deposited on glass. Microscopic examination of the film showed a homogeneous thin layer of fibrin gel.
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A device and method for applying a fibrinogen-based tissue sealant to seamlessly connect human or animal tissues or organ parts, to seal wounds, stop bleeding and the like by mixing fibrin or fibrinogen with blood clot-promoting coagulation factors are disclosed. The device includes two cylindrical compartments for separately containing the separate fluid components of the sealant preparation, which are simultaneously displaced from the respective compartments by means of plungers commonly depressable with the same effective strokes. The plungers may be depressed directly or by means of a common mechanism (e.g., rack and pinion) for accurately controlling the rate of dispensing fluid. The cylindrical compartments are of the same or different cross-sectional area and are arranged either concentrically or side-by-side. The device further includes a means for merging the two fluid components within an outer sleeve housing an inner needle. The sleeve and needle contain conduits for the flow of the two fluid sealant components as they are expressed from the respective compartments. Also disclosed are a convenient means of filling the two compartments, a means for mixing the fluid components, and for atomizing the effluent sealant fluid stream (i.e., spraying).
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BACKGROUND OF THE INVENTION
[0001] The inventions disclosed herein generally relate to mobile phone cases. More specifically, they relates to a mobile phone case integrated with a selfie-stick.
[0002] With the selfie photograph turning into a fashion, selfie-stick also becomes much more popular. Selfie-stick, with a long pole attached to mobile or camera, may function as photo taking assisting device. Hand-held selfie portrait may only include few people due to the limitation of one's arm's length. With the help of a selfie-stick, shooting angle and range are much bigger. More people and larger scale of backgrounds can be included into a single photo. Till now the selfie-stick is a separate part and has not been successfully integrated with a cell phone. The selfie-stick is usually carried separately from the phone or camera. Additional storage space is required to store a selfie-stick. In sum, innovative solutions are needed to solve these issues and shortcomings with current designs of selfie-stick for selfie photo shooting.
SUMMARY
[0003] The mobile phone case designs disclosed herein provides a phone case that not only protects the phone from scratches but also fully integrates a selfie-stick. It provides a fully integrated case that is artistically desirable and easy to carry with no additional burden to the user. The highlight for the present invention is that a foldable and extendable settle-stick is integrated into the back of cellphone case. When the selfie function is not used, the selfie-stick can be fully folded and stored in the cellphone case. When the selfie function is used, the selfie stick could be fully extended out of the case.
[0004] The integrated selfie-stick includes a rotary rod and an adjustable rod. The rotary rod has an L shaped exterior. One side of the rotary rod is attached to the back of the cellphone case. The other side of the rotary rod is attached to the adjustable rod. A selfie remote control button is located on the adjustable rod. The control button is connected with as selfie control device.
[0005] A groove is located at the back of cellphone cover. The groove is designed to store the adjustable rod and the rotary rod.
[0006] An installation hole is located at the back of cellphone case. A fist position lock with an axial hole is inserted into said installation hole to hold tight of the selfie stick. A first connection hole that matches said installation hole is located on one side of said rotary rod. The rotary rod is connected to the installation hole via a first bolt knob. The bolt diameter of said first bolt knob matches the size of the hole in the first position lock. The first bolt knob includes thread in the far end of the bolt. Through the first bolt knob, the rotatory rod is connected with said cellphone case through the first position lock into the installation hole. The end of the bolt may also include a screw nut.
[0007] A first connection component is located on one side of the rotary rod. A second connection hole is located at the top of the first connection component. The axis of the second connection hole is perpendicular to the axis of the first connection hole. A U shaped second connection component is located at the connection section of adjustable rod. A third connection hole that matches with the second connection hole is located at the second connection component. The second connection component connects the first connection component via a second bolt knob. The bolt diameter of the second bolt knob matches the size of the second connection hole. The second bolt knob crosses through said connection holes of the first and second connection components and is screwed into said second connection hole. The second bolt knob includes thread in the far end of the bolt and may include a screw nut.
[0008] The mobile phone case designs disclosed herein include a cellphone case with a main case body and a cellphone back board. The main case body of the cellphone case is designed to cover a cellphone. The selfie-stick connects to the back of the cellphone case. The cellphone back board is detachably attached to the side of the main case body facing a cellphone.
[0009] The mobile phone case designs disclosed herein provide a phone case that not only protects the phone from scratches but also fully integrate a selfie-stick. The case designs disclosed herein may provide extra space for storage of the selfie-stick. It is multifunctional, portable, and provides many easy-to-use features.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is an overall design diagram of one preferred embodiment with a folded selfie-stick.
[0011] FIG. 2 is an overall design diagram of one preferred embodiment with an integrated selfie-stick in use.
[0012] FIG. 3 is a schematic diagram of the various components in a preferred embodiment of the present inventions.
[0013] The figures depicts a cellphone case 1 , a main case body 11 , an installation hole 111 , storage groove 112 , cellphone back board 12 , selfie-stick 2 , rotary rod 21 , a first connection hole 211 , a first connection component 212 , a second connection hole 213 , adjustable rod 22 , selfie control button 221 , a second connection component 222 , a third connection hole 223 , a first bolt knob 23 , the bolt portion of the first knob 231 , a first position lock 24 , the axial hole of the first position lock 241 , a second bolt knob 25 , the bolt portion of the second knob 251 , a cellphone 3 .
DETAILED DESCRIPTION
[0014] The following description provides details with reference to the accompanying drawings. It should be understood that the inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
[0015] As shown in FIGS. 1 through 3 , the mobile phone case disclosed herein includes the main case body 11 , the cellphone back board 12 and selfie-stick 2 .
[0016] As shown in FIGS. 1, 2 and 3 , the main case body of cellphone case 11 may cover and protect a cellphone 3 . The shape and size of the main case body 11 may be redesigned to fit the different brands and shapes of a cellphone 3 . An installation hole 111 is located at the back of the main case body 11 . The installation hole 111 functions as the connection point to selfie-stick 2 . A storage groove 112 is located in the main cellphone case body 11 . The cellphone back board 12 is located inside the main case body 11 , facing a cellphone. The shape and size of the cellphone back board 12 matches to the cellphone 3 . The side of the cellphone back board 12 facing the cellphone 3 is flat. The other side of the cellphone back board 12 connects with the selfie-stick. The main case body 11 and the cellphone back board 12 are detachably attached with snap posts or screws.
[0017] As shown in FIGS. 2 and 3 , the selfie-stick 2 connects to the back of the main cellphone case body. The selfie-stick is extendable. When not used, the selfie-stick 2 may fold into the storage groove 112 .
[0018] As shown in FIG. 3 , the integrated selfie-stick 2 contains a rotary rod 21 and an adjustable rod 22 . The rotary rod 21 has an L shaped exterior. One side of the rotary rod is attached into the back of the main cellphone case body. The other side of the rotary rod is attached to the adjustable rod 22 . This design makes the adjustable and rotary rods easily foldable. To fully integrate the selfie stick into the cellphone case, a first connection hole 211 is located at one side of the rotary rod. The first connection hole is in round shape and matches the installation hole 111 that is located in the main cellphone case body 11 . The rotary rod 21 connects to the main case body 11 via a first bolt knob. The bolt portion 231 is located at the center of the first bolt knob 23 . The length of the first bolt knob 23 is substantially the same or longer than the sum of the thickness of the rotary rod 21 and the main case body 11 , which makes it possible for the bolt knob to pass through the rotary rod 21 and the main case body 11 and reaches to the other side of the main case body 11 . The far end of the first bolt knob has external thread and may have a screw nut. A first position lock 24 is inserted inside the installation hole 111 and cannot rotate. A positioning groove is located in the installation hole 111 . A positioning component, matching the positioning groove, is located at the first position lock 24 . The first position lock 24 is inserted into the positioning groove in the installation hole 111 . The first position lock 24 is then fixed to ensure that the rotary rod remains connected with the main case body. The first position lock includes an axial hole 241 . The rotary rod 21 connects to the back of the main case body 11 . The first connection hole 211 is located on one side of the rotary rod 21 and faces the axial hole 241 in the first position lock 24 . The bolt portion 231 , which is part of first bolt knob 23 , passes through the first connection hole 211 and the axial hole 241 and extends to the other side of the main case body 11 . The end of the bolt portion can be screwed into the main case body 11 . The rotary rod 21 connects to the back side of the main case body 11 .
[0019] The other side of the rotary rod 21 connects with the adjustable rod 22 . A first connection component 212 is located on the other side of rotary rod 21 . The first connection component includes one or more spaced compartments designed hook with the adjustable rod. A second connection hole 213 is located in the first connection component 212 . The second connection hole matches the third connection hole in the second connection component, which allows a connection with the adjustable rod 22 through a second bolt knob 25 . The axis of the second connection hole 213 is perpendicular to the axis of the first connection hole 211 . The selfie-stick 2 can be rotated towards at least three directions, which make it possible to rotate freely to take selfie photos.
[0020] The adjustable rod 22 is designed as a hollow stick that includes a selfie control device. A selfie control button 221 is located on the outside of the adjustable rod 22 and connects to the selfie control device. The design of a selfie control device may be found in prior or current known designs. A U shaped second connection component 222 is located at the connection side of the adjustable rod 22 . The size and shape of the second connection component 222 matches the first connection component 212 . The second connection component 222 can be inserted into the first connection component 212 . A third connection hole 223 , which matches the size of the second connection hole 213 , is located at the second connection component 222 . The bolt portion 251 is located at the center of a second bolt knob 25 . The length of the bolt portion 251 is substantially the same or longer than the length of the first connection component 212 . The far end of the bolt portion 251 has external thread which may be connected to a screw nut. All three sizes, i.e., the diameter of the bolt portion 251 , the diameter of the second connection hole 213 , and the diameter of the third connection hole 223 matches with each other. The bolt portion 251 passes through the first connection component 212 , the connection hole on the second connection component 222 , and extends to the second connection hole 213 located in the rotary rod 21 . The far end of the bolt portion 251 has thread and may be fixed by a screw nut. The rotary rod 21 and the adjustable rod 22 are therefore connected.
[0021] Rotary bolt knobs connects the rotary rod to the main case body 11 and the adjustable rod 22 , which make it possible to rotate freely when taking a selfie photo. The storage groove 112 may store selfie-stick when not in use. These new cellphone cases with a foldable selfie-stick may not only protect a cellphone but also make it convenient to take selfie photo.
[0022] Although exemplary embodiments of the present inventions have been illustrated in the accompanied drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by the following claims.
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A mobile phone case is fully integrated with an extendable selfie stick where the selfie stick can be folded and stored in the back of the mobile phone case when not used. The selfie stick can be unfolded and extended for settle photographs when needed. This mobile phone case combines a selfie stick into a protection case. It is multifunctional, portable, and easy-to-use.
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PRIORITY INFORMATION
This application claims the benefit of U.S. Provisional Application No. 60/589,053, filed on Jul. 19, 2004.
FIELD OF THE INVENTION
The field of the invention related to milling downhole with a bottom hole assembly delivered on coiled tubing with provisions to absorb torque reaction from milling and to collect generated debris near the milling location.
BACKGROUND OF THE INVENTION
Workovers in existing wells can require removal of packers or plugs by milling them out. Other occasions can also occur where there is a need to mill out a tool or even a casing section. If the well is not too deviated, rigid tubing has been used to support a mill and the rotation force provided from surface equipment. Alternatively, where the deviated nature of the wellbore precludes rotation from the surface, the bottom hole assembly includes a mud motor to turn the mill. The bottom hole assembly is still delivered on rigid tubing but such tubing above the mud motor remains stationary, with the output of the mud motor driving the mill below. In either alternative a workover rig must be erected over the well to handle the rigid tubing string for trips into and out of the well. There is a fair amount of expense associated with erecting the rig on site and handling the tubing to assembly and disassemble the string for trips into the well. It would be advantageous if a coiled tubing unit could be used at the surface instead of a workover rig. Being able to use coiled tubing would save time and money for the operator over using rigid tubing. However, the use of coiled tubing creates other issues that are not of concern when using rigid tubing. The main problem is that coiled tubing is considerably weaker than rigid tubing. During milling a reaction torque is created that is passed to the supporting tubing. In the past, milling on coiled tubing has been attempted in small casings that are less than 4-½ inches with equally small mud motors driving the mill. These attempts worked, after a fashion, because the torque output from the motor and the resultant torque reaction from milling was sufficiently small so as to not twist the coiled tubing. If the torque reaction turns the coiled tubing it can raise the mill off the packer being milled or bounce it, resulting in erratic milling. Worse still, the coiled tubing can fail from being over-torqued. For this reason milling with coiled tubing was limited in the past to very small applications, generally with casing sizes fewer than four inches.
The milling process generates debris in the wellbore. Even if a milling job in a larger casing were attempted with small coiled tubing and an equally low powered mud motor, the return flow in the larger casing sizes would reduce the velocity of the returning fluid so as to allow the debris to drop out rather than be carried to the surface for separation with surface equipment. While debris catchers of various designs are known they have operational shortcomings. Some require a separate trip. They generally let the debris-laden fluid passes through an open port on the trip downhole. When the tool is brought uphole, the bypass port is closed and the fluid passes through a screen leaving the debris inside the screen. Some examples of such tools are the H-3015 and the 10084-1 offered by Baker Oil Tools. Some debris catchers can be run in the same trip as the milling equipment but due to the way such tools operate they can't have a mud motor below them. These tools use a venturi effect to direct the cuttings into the tool and generally must be coupled with specially designed mills that create the type of cuttings that will enter this type of debris catcher. One such tool offered by Baker Oil Tool s is the VACS tool. U.S. Pat. No. 6,176,311 illustrated the concepts of central circulation, annulus diversion of debris into the tool, an interior capture area and screen. This design has been improved in the present invention to minimize issues of plugging and damage to the annulus diverter device when running in or removing the tool. Other debris removal tools are described in U.S. Pat. Nos. 5,176,208; 5,402,850; and 6,276,452.
Anchors for tubing downhole are known, as illustrated in U.S. Pat. No. 6,276,452.
The present invention permits small coiled tubing to support large mud motors for big milling jobs. The coiled tubing is anchored in position and the mud motor operates the mill in conjunction with a thruster to keep the mill on the tool being milled. Other variations are envisioned that secure the coiled tubing against torque reaction while allowing the mill to progress and mill out downhole. An improved debris catcher is incorporated into the assembly with greater debris retention capacity and other operational enhancements to improve its operation. These and other aspects of the invention will be more readily apparent to those skilled in the art from the description of the preferred embodiment and the claims that appear below.
SUMMARY OF THE INVENTION
Milling in casing that is over 4-½ inches is done with coiled tubing that is anchored against torque reaction. An improved debris catcher is part of the bottom hole assembly to capture cuttings from the milling. A thruster can be used to maintain weight on the mill during the milling. The coiled tubing supports a mud motor to drive the mill. Return fluid is separated from the cuttings and returned to the surface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 a - e are a sectional elevation of the bottom hole assembly for coiled tubing milling.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 a , coiled tubing 10 is run into casing 12 . At the lower end 14 is a threaded connection 16 to which an anchor 18 is attached. The anchor 18 is preferably of a known design as described in U.S. Pat. No. 6,276,452. It features extending gripping members 20 and 22 that are hydraulically actuated by fluid circulation down the coiled tubing 10 . A connection 24 is at the lower end of the anchor 18 to attach the debris catcher 26 . The debris catcher 26 runs from upper end 28 to lower end 30 in FIG. 1 c . Continuing with the preferred assembly, a jet sub 34 is connected to lower end 30 . A mud motor 36 (shown schematically) is connected to jet sub 34 . A thruster 38 (shown schematically) is connected to mud motor 36 . A mill 40 is connected to the thruster 38 . Mill 40 comes in contact with the object 42 (shown schematically) to be milled in the wellbore. That object 42 could be a packer, a bridge plug, another downhole tool, or a section of casing or tubular. Depending on the specific attributes of the components selected they can be attached in different orders. The thruster 38 can be optionally omitted and instead the anchor 18 can be repositioned periodically during the milling by cutting circulation to release the anchor 18 and letting the assembly move down to a new position. At that time the circulation can begin again and the anchor 18 will take another grip of the casing 12 . Of course, the anchor 18 is above the mud motor 36 to isolate the coiled tubing 10 from reaction torque from the mill 40 milling the object 42 . The coiled tubing 10 can be sized as small as practicable to not only support the load of the bottom hole assembly but also to keep the pressure drop in flow passage 32 at a reasonable level. Initiating flow through the coiled tubing 10 will set the anchor 18 first before any significant milling by mill 40 can take place. At that point the coiled tubing is protected from reaction torque transmitted through the mud motor 36 . The mud motor 36 can be of a type known in the art as well as the thruster 38 whose purpose is to keep weight on the mill 40 to hold it against the object 42 for efficient milling. As long as the anchor 18 is properly sized for the casing 12 , the other components simply need to be small enough to easily pass through the casing 12 . As a result, the illustrated assembly can be rapidly deployed at the surface without a workover rig and the trip time to reach the object 42 to be milled can be greatly reduced as compared to running the bottom hole assembly on rigid tubing. Objects 42 in casing sizes larger than 4-½″ can be easily milled out with coiled tubing smaller than 3-½ inches in diameter. It is conceivable that coil tubing as small as 1-¼″ could be used to support milling equipment in casing as large as 9-⅝″ or larger.
The details of the debris catcher will now be described. Flow enters near the top 28 through passage 32 . A diverter sub 44 has downhole-oriented passages 46 spaced apart from uphole return passages 48 . Arrow 50 shows the flow beyond passages 46 and around the outside of sleeve 52 that is secured at thread 54 to the diverter sub 44 . Flow continues through annular space 56 between the sleeve 52 and the outer screen housing 57 and emerges in FIG. 1 c as arrow 50 . The flow 50 emerges in an annular space 58 around a diverter tube 60 . Seals 62 seal around diverter tube 60 . Accordingly the pressure is directed downwardly through the inside of sleeve 64 as shown by arrow 66 and outside sleeve 64 as shown by arrow 68 . Flow 68 encounters a piston 70 that has a movable bearing 72 below it and a pack off sleeve 74 below the bearing 72 . A return spring 76 biases the pack off sleeve 74 uphole to a retracted position. Pressure on piston 70 represented by arrow 68 pushes the piston 70 and bearing 72 downhole against the pack off sleeve 74 . A stationary ramp 78 catches the lower end 80 of the pack off sleeve 74 to force it out into sealing contact with the casing 12 . In this manner, the pack off sleeve 74 is protected from damage during run in or removal because the return spring 76 keeps it retracted and away from casing 12 until circulation through passage 32 in coiled tubing 10 is established. Another bearing 82 is supported by reverse flow sub 84 . Together bearings 72 and 82 allow the pack off sleeve 74 to rotate relative to the sleeve 64 to promote sealing and to minimize wear on the pack off sleeve 74 .
The flow 66 through sleeve 64 emerges near lower end 30 of the debris catcher 26 in a chamber 86 between restrictor 88 and venturi jet 90 . The venturi jet 90 discharges into return path 92 in diverter tube 60 to reduce pressure in return port 94 so as to draw debris laden fluid in (as will be explained below). Restrictor 88 creates enough backpressure to supply adequate pressure to the venturi jet 90 . This restrictor is optional and can be used when the mill nozzles (not shown) are fairly large so that insufficient backpressure is available for proper operation of the venturi jet 90 . After going through the restrictor 88 the flow 66 goes to the nozzles in the mill 40 and comes back uphole laden with cuttings in annulus 96 as shown by flow arrow 98 .
Flow 98 with cuttings is forced into return port 94 and aided by the action of the venturi jet 90 . It passes up the diverter tube 60 and comes out of outlets 100 The top 102 of the diverter tube 60 is capped off above outlets 100 . A screen 104 has a lower end 106 capped but the annular space 108 outside the screen is left open for the debris-laden flow 98 . The debris free flow 110 goes to the surface outside of the coiled tubing 10 . The debris 112 falls down to catch plate 114 which can be many feet below the lower end 106 of screen 104 .
Those skilled in the art can appreciate some of the improvements in the debris catcher 26 as compared to the design shown in U.S. Pat. No. 6,176,311. The pack off sleeve 74 is retractable for run in and removal to protect it from damage. A venturi jet 90 accelerates the debris-laden flow 98 . The debris-laden flow 98 passes a screen 104 with a relatively large open area reducing the risk of plugging using the random slots of the prior design. The debris storage area below the screen 104 can be quite long to minimize the chance of plugging.
Those skilled in the art will now appreciate that coiled tubing milling is possible with small coiled tubing sizes in casing bigger than 4-½ inches. The coiled tubing is isolated from reaction torque by an anchor. The milling is done with a mud motor with the additional optional use of a thruster to keep weight on the mill. A debris catcher incorporates improvements to enhance performance, capacity and reliability. A hydraulically operated cutter my be used rather than a mill to sever casing.
While the preferred embodiment has been set forth above, those skilled in art will appreciate that the scope of the invention is significantly broader and as outlined in the claims which appear below.
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Milling in casing that is over 4½ inches is done with coiled tubing that is anchored against torque reaction. An improved debris catcher is part of the bottom hole assembly to capture cuttings from the milling. A thruster can be used to maintain weight on the mill during the milling. The coiled tubing supports a mud motor to drive the mill. Return fluid is separated from the cuttings and returned to the surface.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to column assemblies used in the construction of building structures. More particularly, this invention relates to column assemblies having reinforcement rods imbedded within columns and extending from the ends thereof to facilitate alignment of the columns, end to end, during erection.
2. Description of the Background Art
Presently there exists many varieties of construction techniques that employ vertically disposed, floor-height columns which support bearing beams interconnecting adjacent columns, with the bearing beams providing support for the floor above constructed of precast floor slabs, poured-in-place, or the combination of the two.
It is always desirable to erect the column assemblies as precisely vertical as possible while minimizing shoring. In this regard, one technique for minimizing shoring is to extend the reinforcement rods of each column to protrude from their ends and then provide means for aligning the ends via the protruding rods as the columns are stacked vertically one on top of another. In some techniques, the protruding reinforcement rods are aligned by means of an intermediate plate, in others, by slip fitting the rods together. Illustrative examples of such techniques are described in U.S. Pat. No. 976,182, U.S. Pat. No. 1,657,197, U.S. Pat. No. 2,724,261, U.S. Pat. No. 3,613,325, U.S. Pat. No. 3,733,757, U.S. Pat. No. 3,867,805, U.S. Pat. No. 4,081,935, U.S. Pat. No. 4,330,970, U.S. Pat. No. 4,583,336, French Patent 2,387,325 and British Patent 1,045,331.
Of all the above-referenced patents, only U.S. Pat. No. 976,182 employs the use of turnbuckles which threadably engage the aligned ends of the protruding reinforcement rods of columns positioned end to end. Unlike slip-fit sleeves and the other interconnection means shown in the other patents, the turnbuckles taught by U.S. Pat. No. 976,182 provide a means for mechanically interconnecting the rods of adjacent columns stacked one on top of the other. However, the use of turnbuckles for such interconnection requires that the turnbuckles be individually adjusted until the upper column is positioned vertically. Considering the weight of the column, leveling adjustment of the turnbuckles during erection would appear to be difficult since the column would have to remain suspended by a crane as the turnbuckles were threaded onto the rods. Also the total weight of the structure above will have to be carried by the threads of the buckles.
It is an object of this invention to provide an apparatus which overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the column assembly art.
Another object of this invention is to provide a column assembly, comprising in combination a first column having a first end and a second end, at least one first threaded rod extending from the second end of said first column, a second column having a first end and a second end, at least one second threaded rod extending from the first end of the second column in axial and contiguous alignment with the first threaded rod defining a space between the second end of said first column and the first end of the second column, and a threaded sleeve threadably interconnecting the first threaded rod and the second threaded rod.
Another object of this invention is to provide a column assembly described hereinabove, wherein a plurality of the first threaded rods extend from the second end of the first column, wherein a corresponding plurality of the second threaded rods extend from the first end of the second column in axial and contiguous alignment with respective first threaded rods, and wherein a corresponding plurality of the threaded sleeves threadably interconnect respective the first threaded rods and the second threaded rods.
Another object of this invention is to provide a column assembly described hereinabove, wherein the first threaded rods extend from the second end of the first column equal distances and wherein the second threaded rods extend from the first end of the second column equal distances.
Another object of this invention is to provide a column assembly described hereinabove, wherein the threaded sleeves comprise a length less than the distance the first threaded rods extend from the second end of the first column or the distance that the second threaded rods extend from the first end of the second column, thereby allowing said threaded sleeves to be threaded fully onto the first threaded rods or the second rods prior to the rods being positioned in axial and contiguous alignment.
Another object of this invention is to provide a column assembly described hereinabove, further comprising grout means filling the space between the second end of the first column and the first end of the second column.
Another object of this invention is to provide a column assembly described hereinabove, wherein the first column further comprises a capital positioned at the second end of the first column, the capital having a surface area greater than the cross-sectional area of the first column defining a ledge for supporting a bearing beam when the columns are positioned vertically.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
For the purpose of summarizing this invention, this invention comprises a column assembly having a plurality of floor-height columns which are erected vertically, one on top of the other, to define the floors of the building structure to be constructed. The upper end of each column comprises a capital for supporting bearing beams which extend from one column assembly to an adjacent column assembly. The bearing beams provide support for a precast slab floor or a cast-in-place floor.
A primary feature of the invention is the manner in which the columns of each column assembly are interconnected. Specifically, each column comprises a plurality of reinforcement rods which are embedded in the column and extend outwardly from the ends thereof. The rods are cut at precisely equal lengths to extend precisely equal distances from each end of the column. Each rod is threaded in a precise manner with the thread beginning at the same orientation for each rod such that when the columns are stacked end-to-end, the rods are in perfect axial alignment with the thread of one rod continuously leading into the thread of the contiguous rod to which it is aligned.
The precise cutting and threading of the rods extending from the ends of the columns allow a threaded sleeve to be threaded onto the rods extending from the lower end of the upper column and, after stacking of the upper column end-to-end onto a lower column, the threaded sleeve may be threaded onto the axially aligned and contiguous rods extending from the lower column. A rigid mechanical connection is therefore made between adjacent columns sufficient to support the columns vertically without additional shoring. Most importantly, the preciseness of the length of the rods assures that a precisely, vertically aligned column assembly is achieved. Leveling adjustment is therefore not necessary or minimized.
Another feature of the column assembly of the invention is the use as a capital at the upper end of a lower column for supporting bearing beams which straddle adjacent column assemblies so as to provide support for the laying of precast floor slabs or, alternatively, to provide support for pouring a cast-in-place floor.
A still additional feature of the column assembly of the invention is the ability to interconnect the adjacent columns through the bearing beams so as to provide a stronger structure. Likewise, the space created between adjacent columns in a column assembly may be filled with grout or other solidifying material to provide added support for the adjacent, interconnect columns. Finally, the cast-in-place floor or the precast floor slabs may be tied to the lower end of the upper column so as to provide more rigid support.
The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:
FIG. 1 is a front view of the column assembly of the invention;
FIG. 2 is a longitudinal cross-sectional view of the column assembly of the invention employing a precast capital on which is seated bearing beams which support a precast slab floor;
FIG. 2A is a plan view of FIG. 2 taken along lines 2A--2A illustrating the side support precasts;
FIG. 3 is a longitudinal cross-sectional view of the column assembly of the invention employing an integral capital on which is seated bearing beams which support a cast-in-place floor; and
FIG. 4 is a front view of two column assemblies of the invention supporting a bearing beam.
Similar reference characters refer to similar parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the column assembly 10 of the invention comprises a plurality of columns 12 each having an upper end 12U and a lower end 12L. A plurality of reinforcement rods 14 (e.g. 4) are imbedded in each column 12 throughout the length thereof and extend from the upper end 12U and the lower end 12L. Each reinforcement rod 14 is of equal length such that their upper ends 14U extend from the upper end 12U of each column 12 by equal distances and such that their lower ends 14L extend from the lower end 12L of the column 12 by equal distances. Both the upper and lower ends 14U and 14L of the reinforcement rods 14 are threaded with the same thread. The beginning of the thread 16 of the upper end 14U of each reinforcement rod 14 of a column 12 is aligned with the beginning of the thread 16 of the lower end 14L of the corresponding reinforcement rod 14 of an adjacent column 12 so that when the respective ends 14U and 14L of the reinforcement rods 14 are positioned in axial and contiguous alignment, the threads 16 of the ends 14U and 14L form a continuous, uninterrupted thread 16 allowing a threaded sleeve 18 to threadably interconnect the upper end 14U of the reinforcement rods 14 extending from the upper end 12U of the column 12 with the lower end 14L of the reinforcement rods 14 extending from the lower end 12L of an upper column 12. In this regard, the length of threaded sleeve 18 is preferably less than the distance that the end 14U or 14L of the reinforcement rods 14 extend from the ends 14U and 14L of the column 12 thereby allowing the threaded sleeve 18 to be threaded onto the end 14U or 14L prior to positioning the respective ends 14U and 14L of the reinforcement rods 14 of the adjacent columns 12 in axial and contiguous alignment.
During assembly, a lowermost floor-height column 12 is positioned vertically and embedded or otherwise rigidly supported by foundation 20. A threaded sleeve 18 is threaded all the way onto the lower end 14L of each reinforcement rod 14 that extends from the lower end 12L of the columns 12 to be erected. A column 12 is hoisted, such as by means of a crane, above the lowermost column 12 and then lowered such that the lower ends 14L of the reinforcement rods 14 extending from the lower end 12L of the column 12 are in axial alignment with and resting on the upper ends 14U of the reinforcement rods 14 extending from the upper end 12U of the lowermost column 12. A space 19 between the upper end 12U of the lowermost column 12 and the lower end 12L of the adjacent column 12 is created. The threaded sleeves 18 are then threaded downwardly so as to secure the axially and contiguously aligned ends 14U and 14L of the reinforcement rods 14, thereby rigidly securing the rods 14 together and forming a mechanically sound connection between the two adjacent columns 12 separated by the space 19. The threaded sleeves 18 may be tack-welded to the rods 14 to preclude any further threaded movement along either ends 14U or 14L of the reinforcement rods 14. As described below, space 19 may be grouted to provide a more solid support.
Additional floor-height columns 12 may be rigidly connected in series so as to extend the column assembly 12 upwardly to the desired height defining the floors of the structure to be constructed. It should be appreciated that the column assembly 12 as thus constructed comprises a self-supporting, rigid structure that does not require shoring of each added column 12 during assembly.
As shown in FIGS. 2 and 3, the upper end 12U of each column 12 may be provided with a capital, generally indicated by numeral 22, for supporting bearing beams, generally indicated by numeral 24, which straddle adjacent column assemblies 10 aligned in a row. Additional bearing beams 24 may be provided for straddling adjacent rows of column assemblies 10. The bearing beams 24 provide support for a precast floor slab (see FIG. 2). Alternatively, the bearing beams 24 allow, with appropriate shoring, the pouring of a cast-in-place floor supported by the bearing beams 24 (see FIG. 3).
More particularly, referring to FIG. 2, in one embodiment, capital 22 comprises a precast capital 26 having a metal top plate 28. Apertures 30 are formed through the precast capital 26 so as to allow the upper ends 14U of the reinforcement rods 14 to extend therethrough. The precast capital 26 comprises a surface area greater than the cross-sectional area of the column 12 so as to over-hang the column 12 and define four ledges 32 around the four sides of the column 12 for supporting the bearing beams 24.
During assembly, the lowermost column 12 is positioned vertically as hereinabove described. The precast capital 26 is lowered onto the upper end 12U of the lowermost column 12 so that the upper ends 14U of the reinforcement rods 14 extend through apertures 30 in the precast capital 26. Another column 12 (with threaded sleeves 18 installed) is lowered into place with its lower ends 14L of the reinforcement rods 14 extending from its lower end 12L positioned in axial and contiguous alignment with the upper ends 14U of the reinforcement rods 14 extending through apertures 30 from the upper end 12U of the lowermost column 12. The threaded sleeves 18 are then threaded onto the upper ends 14U of the reinforcement rods 14 so as to rigidly interconnect the columns 12. Notably, the thickness of the precast capital 26 is dimensioned relative to the distance by which the upper ends 14U of the reinforcement rods 14 extend from the upper end 12U of the lowermost column 12 such that the threaded sleeves 18 additionally function to rigidly secure the precast capital 26 to the upper end 12U of the column 12 as the threaded sleeves 18 are threaded onto the upper ends 14U of the reinforcement rods 14.
Without departing from the spirit and scope of this invention, it is noted that the precast capital 26 may comprise simply the metal top plate 28 without precast. In such event, the thickness of the capital 22 would be appreciably less than the distance by which the upper ends 14U of the reinforcement rods 14 extend from the upper end 12U of the column 12. The reinforcement rods 14U should be correspondingly dimensioned shorter to allow the threaded sleeve 18 to rigidly secure the metal top plate 28 to the upper end 12U of column 12.
As shown in FIG. 2, the ends of the bearing beams 24 are seated on the respective ledges 32 of capital 22. Means are provided for rigidly securing the bearing beams 24 to the ledges 32 of the capital 22. More particularly, the edges of the bearing beams 24 are rigidly secured to the ledges 32 of the capital 22 by means of a threaded fastener 34 which extends through hole 36 in the end of each bearing beam 24 and through an aligned hole 38 in ledge 32. As shown, the threaded fastener 34 may comprise a rod 40 threaded at both ends for receiving a washer 42 and nut 44 at both ends. A recess 46 may be formed in the lower surface of the ledge 32 for receiving the washer and nut 42 and 44 at the rods 40 lower end. It is noted that a neoprene sheet 48 may be positioned between the ends of the bearing beams 24 and the ledges 32. Also, a dense plastic foam spacer 50 may be provided between the end of the bearing beams 24 and the lower end 12L of the upper column 12.
As mentioned earlier, the bearing beams 24 provide support for a precast floor slab (see FIG. 2) or, alternatively, the bearing beams 24 allow, with appropriate shoring, the pouring of a cast-in-place floor supported by the bearing beams 24 (see FIG. 3).
More specifically, the bearing beams 24 are rigidly connected to opposing ledges 32 formed on opposing sides of the upper 12U of each column 12. As shown in FIG. 2A, a side support precast, generally indicated by numeral 52, is positioned on the two other ledges 32 of the capital 22 to function as a form for pouring grout into the space 19 between the upper end 12U of the lower column 12 and the lower end 12L of the upper column 12. The side support precasts 52 are connected to each other by means of threaded fasteners 54 which pass through space 19 and extend horizontally through holes 56 formed in both the side support precasts 52. Upon tightening, fasteners 54 draw the side support precasts 52 together thereby rigidly clamping the side support precasts 52 about the ends of the bearing beams 24.
The side support precast 52 each comprises at least one pour hole 58 positioned on its superior surface allowing grout 60 (see FIG. 2) to be poured into the space 19 after the side support precast 52 are secured into position. Grout 60 functions to provide added support for the column assembly 10.
After the grout 60 is poured, a plurality of precast floor slabs 62 are positioned on the bearing beams 24 as is conventional in the trade for constructing a floor.
As shown in FIG. 3, in another embodiment of the capital 22, the capital 22 is integrally formed at the upper end 12U of the column 12 to define the four ledges 32 for supporting the bearing beams 24. The ends of the bearing beams 24 are rigidly secured together on opposing sides of the upper column 12 by means of an elongated member 64 which passes through space 19 and extends through angled slots 66 formed through the ends of the bearing beams 24. The elongated member 64 preferably comprises a stranded cable which, after passing through space 19 and angled slots 54, extends along the upper surface of the bearing beams 24.
As illustrated, bearing beams 24 are constructed with protruding anchors 68. Once appropriate shoring is erected, a cast-in-place floor can then be poured as is conventional in the trade. During pouring, the stranded cable 64 and the protruding anchors 68 of the bearing beams 24 ar imbedded thereby rigidly securing the bearing beams 24 on opposing sides of the columns 12. However, for added strength, another elongated member 70, such as a stranded cable, may be positioned through a horizontal hole 72 in the lower end 12L of the upper column 12 to extend along the upper surface of the bearing beams 24 to also be imbedded during pouring of the cast-in-place floor.
Without departing from the spirit and scope of this invention, the cast-in-place floor as described hereinabove may alternatively be used in lieu of the precast floor slabs 62 described in connection with the precast capital 26. Finally, it is noted that when employing four bearing beams 24 seated on the four ledges 32 of the capital 22 (ninety degrees from each other) of the column 12, the side support precasts 52 are not needed. However, in order to fill the space 19 with grout for added support, a pour hole 74 must be formed angularly within the lower end 12L of the column 12 allowing grout to be poured therethrough to fill the space 19 or grouted by means of a pressure pump.
Referring now to FIG. 4, a plurality of column assemblies 10 of the invention may be positioned in a row for supporting a bearing beam 80 having holes 82 positioned transversely therethrough in alignment with the upper ends 14U of the reinforcement rods 14 which extend from the upper end 12U of the columns 12. Holes 82 may be found over-size to facilitate assembly on top of the upper end 12U of the column 12. After assembly, holes 82 may be grouted. A washer plate (not shown) may then be installed over the ends 14U of the rods 14, to provide a base for the threaded sleeves 18. Similar to the above description in regard to capital 22, the length of the upper ends 14U of the rods 14 may be dimensioned such that the threaded sleeves 18 can be tightened onto the upper ends 14U so as to rigidly secure the bearing beam 80 to the upper end 12U of the column 12. This embodiment of bearing beams 80 may be used to support the floor above, or can be used in combination with the columns 12 and capitals 22 described hereinabove.
The present disclosure includes that contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention.
Now that the invention has been described,
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A column assembly having a plurality of floor-height columns which are erected vertically, one on top of the other, to define the floors of the building structure to be constructed. Each column comprises a plurality of reinforcement rods which are embedded in the column and extend outwardly from the ends thereof. The rods are cut at precisely equal lengths to extend precisely equal distances from each end of the column. Each rod is threaded in a precise manner with the thread beginning at the same orientation for each rod such that when the columns are stacked end-to-end, the rods are in perfect axial alignment with the thread of one rod continuously leading into the thread of the contiguous rod to which it is aligned. A threaded sleeve is threaded onto the rods extending from the lower end of the upper column and, after stacking of the upper column end-to-end onto a lower column, the threaded sleeve may be threaded onto the axially aligned and contiguous rods extending from the lower column. A rigid mechanical connection is therefore made between adjacent columns sufficient to support the columns vertically without additional shoring.
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FIELD OF THE INVENTION
[0001] The present invention relates to an anti-pilling processing method of protein-base fiber materials for imparting pilling resistance to protein-base fiber materials such as, for example, wool, silk, and animal fibers. The present invention also relates to protein-base fiber materials having a pilling resistance using the processing method.
BACKGROUND OF THE INVENTION
[0002] Woven and knitted fibers utilizing protein-base fiber materials such as merino type wool, angora, cashmere, alpaca, mohair, camel, lamb wool, etc., have excellent heat retaining properties and stretching properties. These fibers also have enriched hygroscopicity, water repellency, strong shape recovering power without shape crumbling, and elasticity. Consequently, they are suitable as fiber materials for clothes and have been industrially widely produced.
[0003] However, in general, in woven and knitted products of protein-base fiber materials, cellulose-base fibers, etc., there is a problem when the fibers are subjected to friction or impact when worn. The micro fibers entangle with each other or with single fibers to form complicated entaglements or pilling which spoil the appearance of cloth products prepared from such fibers. Pilling also causes trouble in the handling the cloth product. Therefore, the pilling treatment becomes necessary and hand washing becomes necessary when the product is washed.
[0004] Thus, with respect to protein-base fiber materials, it has been reported that processing methods for preventing felting and shrink resistance result in a slight anti-pilling effect. Various anti-pilling processing methods for cellulose-base fibers have been proposed.
[0005] With respect to protein-base fiber materials, however, a by-product pilling has not been reduced to a pilling resistance of class 5 in the pilling test, JIS L1076.
[0006] Processing methods suitable for cellulose-base fibers, when simply applied to the protein-base fiber materials, result in protein-base fiber deterioration by the treating liquid.
SUMMARY OF THE INVENTION
[0007] The present invention has been made in view of the above-described problems in the related art. The object of the invention is to provide an anti-pilling processing method that obtains excellent pilling resistance without spoiling the feel of the protein-base fiber materials. A further object of the invention is to provide protein-base fiber materials having pilling resistance prepared by the above-described method.
[0008] For attaining the above-described objects, the anti-pilling processing method of the invention is as follows: a compound having both of a glycidyl group and a vinyl group, a compound having at least two of either one of the above-described groups, or a glycidyl methacrylate compound are used as a crosslinking agent in a crosslinking reaction in which the pH of a treating liquid containing the above-described crosslinking agent is controlled to be in the range of from 2.0 to 8.0.
[0009] The use of such a crosslinking reaction in the anti-pilling processing method of the invention yields excellent pilling resistance in the protein-base fiber materials, and cloth products without deterioration of the protein-base fiber materials.
DETAILED DESCRIPTION OF THE INVENTION
[0010] In the anti-pilling processing method of the invention the protein-base fiber materials are contacted with a treating liquid which contains a compound having both a glycidyl group and a vinyl group, a compound having at least two of either one of these groups, or a glycidyl methacrylate compound. This compound is used as a crosslinking agent. The crosslinking reaction is carried out by controlling the pH of the treating liquid to be within the range of from 2.0 to 8.0.
[0011] The protein-base fiber material may be a single spun or a mixed spun fiber. If the material contains protein-base fibers such as, for example, wool, silk, animal wool, etc., as the main constituent, composite fibers containing so-called synthetic fibers may be used.
[0012] In the case of animal fibers, it is more desirable to use a material made of, as the main constituent, off-scale fibers, wherein flaky scales are removed. This is because when the off-scale fibers are used, the reactivity of the treatment of the invention is improved. The anti-pilling effect is stabilized, and additionally shrink resistance may be improved.
[0013] In the anti-pilling processing method of the invention, a compound having both of a glycidyl group and a vinyl group, a compound having at least two of either one of the groups, or a glycidyl methacrylate compound is used as a crosslinking agent. That is, the crosslinking agent is one of (1) a compound having both of a glycidyl group and a vinyl group, (2) a compound having at least two glycidyl groups, (3) a compound having at least two vinyl groups, and (4) a glycidyl methacrylate compound.
[0014] Also, in the anti-pilling processing method of the invention, the crosslinking reaction is carried out by maintaining the pH of the treating liquid to the range of from 2.0 to 8.0. When the pH of the treating liquid is in the range described above, the protein-base fiber material is not deteriorated.
[0015] There is no particular restriction on the method of controlling the pH of the treating liquid. For example, when the pH is adjusted to the acidic side formic acid can be used, and when the pH is adjusted to the weak-alkaline side, soda ash can be used.
[0016] The amount of the crosslinking agent, which is added to the treating liquid in the invention, is in the range of usually from 3 to 80% by weight, and preferably from 3 to 20% by weight based on the amount of the fiber material, and the bath ratio can be in the range of, for example, 1:9 to 24. Also, if necessary, from 0.03 to 1% by weight of a catalyst may be added to the treating liquid to improve the efficiency of the crosslinking reaction.
[0017] There are no particular restrictions on the reaction conditions of the crosslinking reaction. However, to improve the reaction efficiency, it is desirable to increase the temperature to from 100 to 105° C. while sufficiently stirring the treating liquid in a treatment bath and to carry out a heat treatment at the temperature for from 1 to 3 hours. After completing the crosslinking reaction at the temperature, water washing and soaping may be carried out. The resultant fiber material of the invention will have pilling resistance.
[0018] The concentration of the treating liquid, the bath ratio, the catalyst, and the reaction conditions of the crosslinking reaction can be changed according to the kind and the processing purpose of the protein-base fiber material outside of the temperatures and times above-described. The fiber material of the invention may be of any type such as cottons, yarns, raw stocks, textiles, knitted products, etc. The anti-pilling processing method of the invention can be applied to any type of woven or knitted product, such as yarns or semi-finished products.
EXAMPLES
[0019] The anti-pilling processing method and the protein-base fiber materials of the invention are also described in the following examples. The invention is not limited to the following examples.
Example 1
[0020] A cheese roll of 500 g per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment is mounted on a cheese dyeing machine for 1 kg test, and water of room temperature is added to the treatment bath such that the bath ratio becomes 1:18.
[0021] While circulating water in the treatment bath, allyl glycidyl ether is added in an amount of 19% by weight to the weight of the fibers as a crosslinking agent.
[0022] Then, 2-2′azobis(2-amidinopropane) di-hydrochloride of 0.3% by weight to allyl glycidyl ether is added as a catalyst.
[0023] By adding formic acid to the above-described treating liquid, the pH of the treating liquid is adjusted to 3.2.
[0024] Thereafter, the treating liquid is circulated, the temperature is gradually raised to 100° C., and the treating liquid is maintained at this temperature for 3 hours. The pH at the end of the reaction is 3.2.
[0025] After a slow cooling treatment, the treating liquid is removed, water washing is repeated three times, and then hot water washing is carried out at 60° C. for 10 minutes. Thereafter, water washing is carried out three times and a softening treatment is applied for 15 minutes at 45° C. to finish the processing treatment.
[0026] The yarns thus obtained were knitted plain to obtain a protein-base fiber material. Using the fabric of Example 1, a pilling test using JIS L1076 ICI type test machine, pilling resistance was evaluated. A very excellent pilling resistance was obtained as shown in Table 2 below.
Example 2
[0027] A cheese roll of 500 g per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment is mounted on a cheese dyeing machine for 1 kg test, and water of room temperature is added to the treatment bath such that the bath ratio becomes 1:18.
[0028] While circulating water in the treatment bath, glycidyl methacrylate is added in an amount of 5% by weight to the weight of the fibers as a crosslinking agent.
[0029] By adding formic acid to the above-described treating liquid, the pH of the treating liquid is adjusted to 2.0.
[0030] Thereafter, the treating liquid is circulated, the temperature is gradually raised to 100° C., and the treating liquid is maintained at this temperature for 3 hours. The pH at the end of the reaction is 2.0.
[0031] After a slow cooling treatment, the treating liquid is removed, water washing is repeated three times, and then hot water washing is carried out at 60° C. for 10 minutes. Thereafter, water washing is carried out three times, and a softening treatment is applied for 15 minutes at 45° C. to finish the treatment.
[0032] The yarns thus obtained were knitted plain, and the pilling test described in Example 1 was conducted. A very excellent pilling resistance was obtained as shown in Table 2 below.
Example 3
[0033] A cheese roll of 500 g per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment is mounted on a cheese dyeing machine for 1 kg test, and water of room temperature is added to the treatment bath such that the bath ratio becomes 1:18.
[0034] While circulating water in the treatment bath, ethylene glycol dimethacrylate is added in an amount of 5% by weight to the weight of the fibers as a crosslinking agent.
[0035] By adding formic acid to the above-described treating liquid, the pH of the treating liquid is adjusted to 3.0.
[0036] Thereafter, the treating liquid is circulated, the temperature is gradually raised to 100° C., and the treating liquid is maintained at this temperature for one hour. The pH at the end of the reaction is 3.0
[0037] After a slow cooling treatment, the treating liquid is removed, water washing is repeated three times, and then hot water washing is carried out at 60° C. for 10 minutes. Thereafter, water washing is carried out three times, and a softening treatment is applied for 15 minutes at 45° C. to finish the treatment.
[0038] The yarns thus obtained were knitted plain, and the pilling test described in Example 1 was conducted. A very excellent pilling resistance was shown as in Table 2 below.
Example 4
[0039] A cheese roll of 500 g per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment is mounted on a cheese dyeing machine for 1 kg test, and water of room temperature is added to the treatment bath such that the bath ratio becomes 1:18.
[0040] While circulating water in the treatment bath, ethylene glycol diglycidyl ether is added in an amount of 12% by weight to the weight of the fibers as a crosslinking agent.
[0041] By adding formic acid to the above-described treating liquid, the pH of the treating liquid is adjusted to 4.2.
[0042] Thereafter, the treating liquid is circulated, the temperature is gradually raised to 100° C., and the treating liquid is maintained at this temperature for 3 hours. The pH at the end of the reaction is 4.2.
[0043] After a slow cooling treatment, the treating liquid is removed, water washing is repeated three times, and then hot water washing is carried out at 60° C. for 10 minutes. Thereafter, the yarns are dyed to black by an ordinary dyeing condition, and a softening treatment is carried out.
[0044] The yarns thus obtained were knitted plain, and the pilling test described in Example 1 was conducted. A very excellent pilling resistance was shown as in Table 2 below.
Example 5
[0045] A cheese roll of 500 g per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment is mounted on a cheese dyeing machine for 1 kg test, and water of room temperature is added to the treatment bath such that the bath ratio becomes 1:18.
[0046] While circulating water in the treatment bath, ethylene glycol diglycidyl ether is added in an amount of 12% by weight to the weight of the fibers as a crosslinking agent.
[0047] Aluminum chloride is added to the treating liquid as a catalyst in an amount of 1% by weight to the amount of ethylene glycol diglycidyl ether. In this case, the pH of the treating liquid was 7.4.
[0048] Thereafter, the treating liquid is circulated, the temperature is gradually raised to 100° C., and the treating liquid is maintained at this temperature for 2 hours. The pH at the end of the reaction is 7.4.
[0049] After a slow cooling treatment, the treating liquid is removed, water washing is repeated three times, and hot water washing is carried out at 60° C. for 10 minutes. Thereafter, the yarns are dyed to black by an ordinary dyeing condition, and a softening treatment is carried out.
[0050] The yarns thus obtained were knitted plain and the pilling test described in Example 1 was conducted. A very excellent pilling resistance was shown as in Table 2 below.
Example 6
[0051] A cheese roll of 500 g per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment is mounted on a cheese dyeing machine for 1 kg test, and water of room temperature is added to the treatment bath such that the bath ratio becomes 1:18.
[0052] While circulating water in the treatment bath, ethylene glycol diglycidyl ether is added in an amount of 12% by weight to the weight of the fibers as a crosslinking agent.
[0053] Then, 100 g/liter of Glauber's salt is added.
[0054] By adding soda ash to the above-described treating liquid, the pH of the treating liquid is adjusted to 8.0.
[0055] Thereafter, the treating liquid is circulated, the temperature is gradually raised to 100° C., and the treating liquid is maintained at this temperature for 2 hours. The pH at the end of the reaction is 8.0.
[0056] After a slow cooling treatment, the treating liquid is removed, water washing is repeated three times, and then hot water washing is carried out at 60° C. for 10 minutes. Thereafter, the yarns are dyed to black by an ordinary dyeing condition, and a softening treatment is carried out.
[0057] The yarns thus obtained were knitted plain, and the pilling test described in Example 1 was conducted. A very excellent pilling resistance was shown as in Table 2 below.
Comparative Example 1
[0058] A cheese roll of 1 kg per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment was dyed to an ordinary black dye color using a cheese dyeing machine for 1 kg test, and then was subjected to a softening treatment for 15 minutes at 45° C. The yarns thus obtained were knitted plain to prepare a fabric.
Comparative Example 2
[0059] A cheese roll of 500 g per one yarn of off-scale wool yarns of 1/48 count subjected to a scouring treatment is mounted on a cheese dyeing machine for 1 kg test, and water of room temperature is added to the treatment bath such that the bath ratio becomes 1:18.
[0060] While circulating water in the treatment bath, glycidyl methacrylate is added in an amount of 5% by weight to the weight of the fibers as a crosslinking agent.
[0061] By adding sodium hydroxide to the above-described treating liquid, the pH of the treating liquid is adjusted to 11.7.
[0062] Thereafter, the treating liquid is circulated, the temperature is gradually raised to 100° C., and the treating liquid is maintained at this temperature for 3 hours. The pH at the end of the reaction is 11.7.
[0063] After a slow cooling treatment, the treating liquid is removed, water washing is repeated three times, and then hot water washing is carried out at 60° C. for 10 minutes. Thereafter, water washing is carried out three times, and a softening treatment is applied for 15 minutes at 45° C. to finish the treatment.
[0064] Preparation of a fabric was attempted using the yarns thus obtained. However, since the yarns were deteriorated and their strength was lowered, a fabric could not be prepared.
[0065] Characteristics and conditions of Examples 1 to 6 and Comparative Examples 1 and 2 are summarized in Table 1. The test results are summarized in Table 2.
[0066] The crosslinking agent “allyl glycidyl ether” used in Example 1 is an example as a compound having one glycidyl group and one vinyl group, the crosslinking agent “ethylene glycol dimethacrylate” used in Example 3 is as a compound having two vinyl groups, the crosslinking agent “ethylene glycol glycidyl ether” used in Examples 4 to 6 is as a compound having two glycidyl groups. The purities of the crosslinking agents used in the examples were almost 100%.
TABLE 1 pH of Crosslinking Agent Added to Treating Treating Liquid Pattern Liquid Example 1 Allyl glycidyl ether 2 3.2 Example 2 Glycidyl methacrylate 4 2.0 Example 3 Ethylene glycol dimethacrylate 3 3.0 Example 4 Ethylene glycol diglycidyl ether 1 4.2 Example 5 Ethylene glycol diglycidyl ether 1 7.4 Example 6 Ethylene glycol diglycidyl ether 1 8.0 Comparative — — 6.8 Example 1 Comparative Glycidyl methacrylate — 11.7 Example 2
[0067] [0067] TABLE 2 (Using JIS L1076 ICI type test machine) Pilling Test Results Example 1 Class 5 Example 2 Class 5 Example 3 Class 5 Example 4 Class 5 Example 5 Class 5 Example 6 Class 5 Comparative Example 1 Class 2 Comparative Example 2 —
[0068] As shown in Table 2, the protein-base fiber materials of Examples 1 to 6 have excellent pilling resistance. The pilling test results by JIS L1076 method of each are class 5. Also, as shown in Examples 1 to 6, since in the processing method of the invention, the pH of each treating liquid is adjusted to the range of from 2.0 to 8.0, the protein-base fiber materials are not deteriorated as in Comparative Example 2. Therefore, these fiber materials have sufficient practical usable properties.
[0069] The anti-pilling processing method of the invention yields an excellent pilling resistance to the protein-base fiber materials without spoiling the feel of the protein-base fiber materials. Also, since in the anti-pilling processing method of the invention, the pH of the treating liquid is adjusted to the range of from 2.0 to 8.0, the fibers are not deteriorated by the treating liquid.
[0070] The processing method of the invention yields the excellent pilling resistance far greater than the slight pilling resistance obtained as a by-product of other processing methods aimed at preventing felting and shrink resistance. The functional properties of a protein-base fiber material processed according to the present invention are improved. These materials can be used not only as general cloth materials but also in stockings and clothes for sports, etc., which are liable to pilling damage. Also, since the anti-pilling processing method of the invention does not require specific equipment and the crosslinking agents used are relatively inexpensive, the method of the invention is also economical and practical.
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An anti-pilling processing method of protein-base fiber materials, which comprises contacting said protein-base fiber materials with a treating liquid at a pH ranging from 2.0 to 8.0, said treating liquid comprising a crosslinking agent selected from the groups consisting of a compound having both of a glycidyl group and a vinyl group, a compound having at least two glycidyl groups, a compound having at least two vinyl groups, and a glycidyl methacrylate compound as a crosslinking agent, wherein said protein-base fiber is crosslinked by said compound.
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FIELD OF THE INVENTION
This invention relates to a process for preparing aqueous blends of sulfo-polyesters and solid acrylic resins without volatile organic compounds (VOC's) and surfactants. More specifically, the acrylic resins are characterized by an inverse relationship between the molecular weight and acid number of the resin, and the sulfo-polyesters contain at least 12 mole percent of a difunctional sulfomonomer. The aqueous sulfo-polyester/acrylic resin blends of the present invention are useful in inks, overprint varnishes, primers, paints, and coatings.
BACKGROUND OF THE INVENTION
Organic solvents that evaporate during the application of coatings and inks contribute significantly to a wide variety of air quality problems. Sunlight is one of the key factors that cause these chemicals to react with each other, thus the term "photochemical smog". These polluting organic solvents are most commonly referred to as Volatile Organic Compounds (VOC's). Ozone is formed by photochemical reactions between nitrogen oxides from fuel combustion and VOC's. Elevated ozone concentrations reduce lung function, aggravate allergies, damage vegetation and cause eye irritations.
Consequently, the Environmental Protection Agency (EPA) and local Air Quality Management Districts have stepped up their efforts to regulate the amount of VOC's. Although coating and ink formulations represent only a small segment of the total market, any reduction of VOC's from these products will help achieve acceptable environmental conditions, and help prepare the industry for the probability of more stringent air pollution regulations in the future.
U.S. Pat. Nos. 4,704,309 and 4,738,785 relate to aqueous ink compositions containing a water dispersible sulfo-polyester. Inks containing such water dispersible sulfo-polyesters have many desirable properties such as good adhesion to a variety of substrates and a wide viscosity range. However, such inks display poor water resistance and poor block resistance on certain substrates.
U.S. Pat. Nos. 4,921,899 and 5,075,364 disclose ink compositions containing water dispersible sulfo-polyesters, acrylic polymer emulsions, surfactants and volatile organic compounds. Inks containing the blend of these polymers exhibit improved block, alcohol and water resistance as compared to inks containing the water dispersible polyester alone. The presence of surfactants, however, in the ink formulations creates several problems related to ink stability, printing process and print quality of the ink film.
U.S. Pat. Nos. 4,996,252 and 5,039,339 disclose ink compositions containing blends of water dispersible sulfo-polyesters and acrylic polymer emulsions. The acrylic polymer emulsions have molecular weights of greater than 200,000. In contrast, the blends of the present invention do not contain acrylic polymer emulsions.
Copending commonly assigned U.S. Pat. application Nos. 638,929 and 638,912 disclose processes for preparing water-dispersible sulfo-polyesters and acrylic resin blends. However, the acrylic resins used in the preparation of the blends require volatile organic compounds in the range of 7-15 weight percent. Without such volatile compounds, the blends gel upon cooling.
The present inventor has unexpectedly developed a process for preparing blends of water dispersible sulfo-polyesters and acrylic resins which do not contain volatile organic compounds and surfactants. Moreover, the present inventor has unexpectedly determined that a correlation exists between the molecular weight and the acid number of the acrylic resin. The blends produced by the process of the present invention provide ink compositions with good water resistance and good block resistance.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a process for preparing blends of water dispersible sulfo-polyesters and acrylic resins which exhibit good water resistance and good block resistance.
Another object of the present invention is to provide a process for preparing blends of water dispersible sulfo-polyesters and acrylic resins which do not contain volatile organic compounds.
These and other objects are accomplished herein by a process for preparing aqueous sulfo-polyester/acrylic resin blends without volatile organic compounds, said process comprising the following steps:
(A) contacting a solid acrylic resin with a solubilizing amount of an alkaline solution comprising an amine or ammonium compound dissolved in water so as to achieve an acrylic resin solution having a pH of at least 8, said acrylic resin comprising repeating units of the formula ##STR1## wherein R is selected from the group consisting of hydrogen and an alkyl group having 1 to 20 carbon atoms, and R 1 is selected from the group consisting of hydrogen and methyl, provided that the molecular weight and acid number of the acrylic resin is inversely related;
(B) heating the acrylic resin solution of step (A) at a temperature of 60° C. to 99° C. to result in an acrylic resin solution having a pH of 7.5 to 9;
(C) contacting the acrylic resin solution of step (B) with a water dispersible polyester consisting essentially of repeat units from:
(a) a dicarboxylic acid selected from the group consisting of aromatic dicarboxylic acids, saturated aliphatic dicarboxylic acids, cycloaliphatic dicarboxylic acids, and combinations thereof;
(b) a diol; and
(c) a difunctional sulfomonomer containing at least one sulfonate group attached to an aromatic nucleus wherein the functional groups are hydroxy, carboxy or amino, provided the difunctional sulfomonomer is present in an amount from 12 to 25 mole percent based on 100 mole percent dicarboxylic acid and 100 mole percent diol;
said contacting occurring under agitation and at a temperature of 60° C. to 99° C. to result in a polymer blend wherein the sulfo-polyester is dispersed in the acrylic resin solution, and the weight ratio of acrylic resin to sulfo-polyester is 10:90 to 90:10; and
(D) cooling the polymer blend while applying agitation.
DESCRIPTION OF THE INVENTION
The process of the present invention involves four steps. In the first step, an essentially solid acrylic resin is added to an alkaline solution to form an acrylic resin solution. It is important that agitation be applied to the solution while the addition is taking place. The alkaline solution may comprise an amine or ammonium compound dissolved in water. Examples of useful amine or ammonium compounds are ammonium hydroxide, methyl amine, methyl ethyl amine, and the like. The amine or ammonia compounds should be present in an amount such that the acrylic resin has a pH of at least about 8. A pH of less than about 8 results in precipitation and/or separation of the acrylic resin. The first step is preferably conducted at a temperature of from 18° C. to 50° C.
The acrylic resin contains repeating units of the formula ##STR2## wherein R is hydrogen, or an alkyl group having 1 to 20 carbon atoms, and R 1 is hydrogen or a methyl group. The alkyl group may be a straight, branched, or cyclic alkyl group. Suitable alkyl groups include methyl, ethyl, propyl, isopropyl, n butyl, sec butyl, isobutyl, tertbutyl, hexyl, heptyl, 2-ethylhexyl, 2-ethylbutyl, dodecyl, hexadecyl, 2-ethoxyethyl and cyclohexyl. Optionally, the alkyl group may have up to two substituents selected from C 1 -C 6 alkoxy and halogen. Preferably, R is a straight, branched, or cyclic alkyl group having 1 to 10 carbon atoms which is substituted with up to two substituents selected from C 1 -C 6 alkoxy, chlorine and bromine.
The weight average molecular weight of the solid acrylic resin is 1,000 to 9,000 preferably 1,500 to 8,000. The acrylic resin has an acid number of 140 to 250, preferably 160 to 235. In addition, it is critical that the molecular weight and the acid number of the acrylic resin within such ranges be inversely related. For example, it has been determined that a solid acrylic resin having a molecular weight of 8,000 and an acid number of 160 and an acrylic resin having a molecular weight of 1,700 and an acid number of 235 are compatible with a sulfo-polyester in a non alcohol system. However, it has also been determined that an acrylic resin having a molecular weight of 8,000 and an acid number of 200 is not compatible with a sulfo-polyester in a non alcoholic system.
The acrylic resin may optionally contain styrene repeating units, acrylonitrile repeating units, or a mixture thereof. Useful acrylic resins are commercially available under the tradename "JONCRYL", especially JONCRYL 682 and JONCRYL 683 which are styrene/acrylic copolymers from S. C. Johnson and Sons, Inc., Racine, Wis., and "VANCRYL" from Vantage.
The second step of the process involves heating the acrylic resin solution of step (A) at a temperature of about 60° C. to about 99° C. to result in an acrylic resin solution having a pH of 7.5 to 9. In this step, excess ammonia or amine is driven off which decreases the pH. The pH of the acrylic resin solution should not be allowed to fall below 7.5 since precipitation or separation of the acrylic resin solution may occur. Preferably, the temperature for step (B) is 70° C. to 95° C.
The third step involves adding a water-dispersible or water dissipatable sulfo-polyester to the acrylic resin solution of Step (B) at a temperature of 60° C. to 99° C. while continuously applying agitation in order to disperse the sulfo-polyester in the acrylic resin solution. Preferably, the temperature for Step (C) is 75° C. to 95° C. The weight ratio of acrylic resin to sulfo-polyester is 10:90 to 90:10, preferably 70:30 to 30:70.
The sulfo-polyester is a water-dispersible or water-dissipatible, linear polyester. The sulfo-polyester contains repeat units from a dicarboxylic acid, a diol and a difunctional sulfomonomer. The sulfomonomer must be present in an amount of at least 12 mole percent of the dicarboxylic acid component based on 100 mole percent dicarboxylic acid and 100 mole percent diol. Dicarboxylic acids useful in the present invention include aromatic dicarboxylic acids preferably having 8 to 14 carbon atoms, saturated aliphatic dicarboxylic acids preferably having 4 to 12 carbon atoms, and cycloaliphatic dicarboxylic acids preferably having 8 to 12 carbon atoms. Specific examples of dicarboxylic acids are: terephthalic acid, phthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, cyclohexanedicarboxylic acid, cyclohexanediacetic acid, diphenyl-4,4'-dicarboxylic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and the like. The sulfo-polyester may be prepared from two or more of the above dicarboxylic acids.
It should be understood that use of the corresponding acid anhydrides, esters, and acid chlorides of these acids is included in the term "dicarboxylic acid".
The diol component of the polyester includes cycloaliphatic diols preferably having 6 to 20 carbon atoms or aliphatic diols preferably having 3 to 20 carbon atoms. Examples of such diols are: ethylene glycol, diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, hexane-1,6-diol, 3-methylpentanediol-(2,4), 2-methylpentanediol-(1,4), 2,2,4-trimethylpentane-diol-(1,3), 2-ethylhexanediol-(1,3), 2,2-diethylpropane-diol-(1,3), hexanediol-(1,3), 1,4-di-(hydroxyethoxy)-benzene, 2,2-bis-(4-hydroxycyclohexyl)-propane, 2,4-dihydroxy-1,1,3,3-tetramethyl-cyclobutane, 2,2-bis-(3-hydroxyethoxyphenyl)-propane, and 2,2-bis-(4-hydroxypropoxyphenyl)-propane. The sulfo-polyester may be prepared from two or more of the above diols.
The difunctional sulfomonomer component of the sulfo-polyester may be a dicarboxylic acid or an ester thereof containing a sulfonate group (--SO 3 - ), a diol containing a sulfonate group, or a hydroxy acid containing a sulfonate group. The cation of the sulfonate salt may be Na+, Li+, K+, NH 4 +, and substituted ammonium. The term "substituted ammonium" refers to ammonium substituted with an alkyl or hydroxy alkyl radical having 1 to 4 carbon atoms. The difunctional sulfomonomer contains at least one sulfonate group attached to an aromatic nucleus wherein the functional groups are hydroxy, carboxy or amino. Advantageous difunctional sulfomonomer components are those wherein the sulfonate salt group is attached to an aromatic acid nucleus such as benzene, naphthalene, diphenyl, oxydiphenyl, sulfonyldiphenyl or methylenediphenyl nucleus. Preferred results are obtained through the use of sulfophthalic acid, sulfoterephthalic acid, sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and their esters. The sulfomonomer must present in an amount of at least 12 mole percent, preferably 15 to 25 mole percent, and most preferably 17 to 20 mole percent, based on 100 mole percent dicarboxylic acid. Sulfo polyesters containing less than 12 mole percent of the difunctional sulfomonomer form unstable blends with acrylic resins.
Preferably, the water dispersible sulfo-polyester is derived from a mixture of dicarboxylic acids consisting of isophthalic acid (or ester) and 5-sodio-sulfoisophthalic acid, a diol component consisting of diethylene glycol, or a mixture of diols consisting of 45 to 80 mole percent diethylene glycol with the remaining diol being either ethylene glycol or 1,4-cyclohexane dimethanol. More preferably, the mixture of diols contains 52 to 56 mole percent diethylene glycol and 48 to 44 mole percent 1,4-cyclohexanedimethanol.
The inherent viscosity of the sulfo-polyester should be in the range of 0.1 to 0.5 dl/g as measured in a 60/40 parts by weight solution of phenol/tetrachloroethane at 25° C. at a concentration of 0.25 grams of polymer in 100 mL of the solvent. Preferably, the inherent viscosity of the sulfo-polyester is 0.28 to 0.35 dl/g.
The acrylic resin and the sulfo-polyester should be compatible with each other. The term "compatible" means that a blend of acrylic resin and sulfo polyester in water will not gel or have a significant increase in viscosity after being held at 120° F. (48.9° C.) for 24 hours. The term "gel" means that the blend is not pourable at room temperature.
The fourth step, Step (D), in the process of the present invention involves cooling the polymer blend formed in Step (C). The blend may be used at any temperature, however, for most applications a temperature of about 15° C. to about 25° C. is preferred. It is important to apply agitation, preferably continuously, during this step. Upon cooling, the polymer blend should have a Brookfield viscosity of about 10 cps to about 1,000 cps as measured at 30 rpm. More preferably, the Brookfield viscosity should be 20 cps to 500 cps. The polymer blend contains about 5 to about 50 weight percent solids, preferably 15 to 40 weight percent solids. In addition, the pH of the blend is about 7 to about 8. Upon drying, the polymer blend has an I.V. of about 0.05 to about 0.30, preferably 0.1 to 0.2, and an acid number of about 20 to about 100, preferably 35 to 80.
The materials and testing procedures used for the results shown herein are as follows:
Brookfield viscosity was determined according to ASTM D2196.
Inherent viscosity (I.V.) was determined according to ASTM D2857-70. The I.V. was measured at 25° C. using 0.25 grams of polymer per 100 ml of a solvent consisting of 60% by weight phenol and 40% by weight tetrachloroethane. The units for reporting I.V. are deciliters/gram. The I.V. was determined by heating the polymer/solvent system at 120° C. for 15 minutes, cooling the solution to 25° C. and measuring the time of flow at 25° C. The I.V. is calculated from the equation: ##EQU1## where: (η)=inherent viscosity at 25° C. at a polymer concentration of 0.25 g/100 mL of solvent;
ln=natural logarithm;
t s =sample flow time;
t o =solvent blank flow time; and
C=concentration of polymer in grams per 100 mL of solvent=0.25.
The acrylic resins used in the examples are:
Joncryl 682® resin is available from Johnson Wax and is an acrylic resin having a molecular weight of 2,500, an acid number of 230, and a Tg of 50° C.
Joncryl 683® is available from Johnson Wax and is an acrylic resin having a molecular weight of 8,000, an acid number of 150, and a Tg of 74° C.
The water-dispersible sulfo polyesters used in the examples are:
A. Sulfo-Polyester A was prepared as follows: A 500 mL round bottom flask equipped with a ground-glass head, an agitator shaft, nitrogen inlet and a side arm was charged with 74.0 grams of isophthalic acid, 16.0 grams of 5-sodiosulfoisophthalic acid, 106.0 grams of diethylene glycol, sufficient titanium isopropoxide to provide 50 ppm of titanium, and 0.45 grams of sodium acetate tetrahydrate. The flask was immersed in a Belmont bath at 200° C. for two hours under a nitrogen sweep. The temperature of the bath was increased to 280° C. and the flask was heated for one hour under reduced pressure of 0.5 to 0.1 mm of Hg. The flask was allowed to cool to room temperature and the copolyester was removed from the flask. The copolyester had an I.V. of about 0.42 and a glass transition temperature of about 30° C. as measured using a differential scanning calorimeter (DSC). The copolyester was extruded and pelletized.
A 28% solids dispersion of Sulfo-Polyester A in water was prepared by heating the water to a temperature of 75° C. to 85° C. and adding the required amount of pellets while agitating at a rate sufficient to maintain the pellets in suspension. The heating was continued until all the pellets were dispersed, approximately, 20 to 30 minutes. Water was added to replace evaporation loss. The dispersion was cooled and filtered.
B. Sulfo-Polyester B was prepared as follows: A 500 mL round bottom flask equipped with a ground-glass head, an agitator shaft, nitrogen inlet and a side arm was charged with 74.0 grams of isophthalic acid, 16.0 grams of 5-sodiosulfoisophthalic acid, 83.0 grams of diethylene glycol, 16.0 grams of 1,4-cyclohexanedimethanol, sufficient titanium isopropoxide to provide 50 ppm of titanium, and 0.45 grams of sodium acetate tetrahydrate. The flask was immersed in a Belmont bath at 200° C. for one hour under a nitrogen sweep. The temperature of the bath was increased to 230° C. for one hour. The temperature of the bath was increased to 280° C. and the flask was heated for 45 minutes under reduced pressure of 0.5 to 0.1 mm of Hg. The flask was allowed to cool to room temperature and the copolyester was removed from the flask. The copolyester had an I.V. of about 0.36 and a glass transition temperature of about 38° C. as measured using a differential scanning calorimeter (DSC). The copolyester was extruded and pelletized.
A 28% solids dispersion of Sulfo-Polyester B in water was prepared by heating the water to a temperature of 90° C. to 95° C. and adding the required amount of pellets while agitating at a rate sufficient to maintain the pellets in suspension. The heating was continued until all the pellets were dispersed, approximately, 20 to 30 minutes. Water was added to replace evaporation loss. The dispersion was cooled and filtered.
C. Sulfo-Polyester C was prepared as follows: A 500 mL round bottom flask equipped with a ground glass head, an agitator shaft, nitrogen inlet and a side arm was charged with 136.0 grams of isophthalic acid, 53.0 grams of 5-sodiosulfoisophthalic acid, 155.0 grams of diethylene glycol, 78.0 grams of 1,4-cyclohexanedimethanol, sufficient titanium isopropoxide to provide 50 ppm of titanium, and 1.48 grams of sodium acetate tetrahydrate. The flask was immersed in a Belmont bath at 200° C. for one hour under a nitrogen sweep. The temperature of the bath was increased to 230° C. for one hour. The temperature of the bath was increased to 280° C. and the flask was heated for 45 minutes under reduced pressure of 0.5 to 0.1 mm of Hg. The flask was allowed to cool to room temperature and the copolyester was removed from the flask. The copolyester had an I.V. of about 0.33 and a glass transition temperature of about 55° C. as measured using a differential scanning calorimeter (DSC). The copolyester was extruded and pelletized.
A 28% solids dispersion of Sulfo-Polyester C in water was prepared by heating the water to a temperature of 85° C. to 90° C. and adding the required amount of pellets while agitating at a rate sufficient to maintain the pellets in suspension. The heating was continued until all the pellets were dispersed, approximately, 20 to 30 minutes. Water was added to replace evaporation loss. The dispersion was cooled and filtered.
The composition of Sulfo-Polyesters A, B and C are summarized as follows:
______________________________________Sulfo- IPA SIP DEG CHDMPolyester Mole % Mole % Mole % Mole % I.V. Tg______________________________________A 89 11 100 0 .42 30B 89 11 78 22 .36 38C 82 18 34 46 .33 55______________________________________
The invention will be further illustrated by a consideration of the following examples, which are intended to be exemplary of the invention. All parts and percentages in the examples are on a weight basis unless otherwise stated.
EXAMPLE 1
This example illustrates the preparation of an aqueous 70/30 weight percent blend of Sulfo-Polyester C and an acrylic resin. The blend was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 682 ® Flakes 175.0 9.0Polyester C Pellets 408.0 21.0Ammonium Hydroxide (28% soln.) 44.0 2.2Water 1315.0 67.8______________________________________
The following procedure was used for preparing the blend:
1. Water and NH 4 OH were combined to form an alkaline solution. Joncryl 682® flakes were added to the alkaline solution while stirring was applied to form a solution.
2. Excess ammonia was removed by heating the solution to 90° C. while continuously stirring the solution.
3. While the solution was at 90° C., Sulfo-Polyester C pellets were added while stirring was continued to form a polymer blend.
4. The polymer blend was allowed to cool to about 25° C. while stirring was continued.
The blend was stored at room temperature for six months during which time no phase separation occurred.
EXAMPLE 2
This example is similar to Example 1 except that Joncryl 683® was used instead of Joncryl 682®. The polymer blend was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 683 Flake 120.0 8.33Sulfo-Polyester C 280.0 19.45NH.sub.4 OH (28% soln.) 20.0 1.39Water 1020.0 70.83______________________________________
The polymer blend had a solids content of 28.5% and an inherent viscosity of 0.182. The blend was stored at room temperature for six months during which time no phase separation occurred.
EXAMPLE 3
This example is similar to Example 2 except that the ratio of Sulfo polyester C/Joncryl 683® was 60/40 instead of 70/30. The polymer blend was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 683 ® 360.0 8.56Sulfo-Polyester C 540.0 12.84NH.sub.4 OH (28% soln.) 90.0 2.14Water 3214.0 76.46______________________________________
The polymer blend had a solids content of 26.4%, an inherent viscosity of 0.181, and a Brookfield viscosity at 25° C. of 10 cps. The blend was stored at room temperature for six months during which time no phase separation occurred.
EXAMPLE 4
This example is similar to Example 2 except that the ratio of Sulfo-Polyester C/Joncryl 683® was 65/35 instead of 70/30. The polymer blend was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 683 ® 140.0 8.56Sulfo-Polyester C 260.0 15.90NH.sub.4 OH (28% soln.) 35.0 2.14Water 1200.0 73.40______________________________________
The polymer blend had a solids content of 27.9%, an inherent viscosity of 0.152, and a Brookfield viscosity at 25° C. of 11 cps. The blend was stored at room temperature for six months during which time no phase separation occurred.
EXAMPLE 5
This example is similar to Example 2 except that the ratio of Sulfo-Polyester C/Joncryl 683® was 50/50 instead of 70/30. The polymer blend was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 683 ® Flakes 150.0 14.29Sulfo-Polyester C 150.0 14.29NH.sub.4 OH (28% soln.) 37.5 3.57Water 712.5 67.85______________________________________
The polymer blend had a solids content of 31.6%, an inherent viscosity of 0.144, and a Brookfield viscosity at 25° C. of 11.5 cps. The blend was stored at room temperature for six months during which time no phase separation occurred.
EXAMPLE 6
This example is similar to Example 2 except that the ratio of Sulfo-Polyester C/Joncryl 683® was 40/60 instead of 70/30. The polymer blend was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 683 ® Flakes 180.0 16.36Sulfo-Polyester C 120.0 10.91NH.sub.4 OH (28% soln.) 45.0 4.09Water 755.0 68.64______________________________________
The polymer blend had a solids content of 29.9%, an inherent viscosity of 0.124, and a Brookfield viscosity at 25° C. of 11.0 cps. The blend was stored at room temperature for six months during which time no phase separation occurred.
EXAMPLE 7
In this example, the freeze thaw stability of the Sulfo-Polyester/acrylic resin blends prepared in Examples 1-6 was examined. Samples of the polymer blends prepared in Examples 1-6 were placed in a freezer at 0° C. After 24 hours, the samples were removed from the freezer, and thawed at 25° C. The Brookfield viscosity of each sample was measured. This process was repeated for up to five freeze-thaw cycles.
The freeze-thaw stability test results indicated that the Brookfield viscosity of the samples did not significantly increase. The Brookfield viscosity of the samples even after five freeze-thaw cycles remained in the range of 10-13 cps. Such results indicate that the polymer blends prepared in Examples 1-6 are freeze-thaw stable.
EXAMPLE 8
In this example, the storage stability or shelf-life of the Sulfo-Polyester/acrylic resin blends prepared in Examples 1-6 was examined. Samples of the polymer blends prepared in Examples 1-6 were stored at 0° C., 25° C. and 50° C. for three weeks. The Brookfield viscosity of each sample was determined at the end of the storage period and compared to the initial Brookfield viscosity.
The storage stability test results indicated that the Brookfield viscosity of the samples did not significantly increase. The Brookfield viscosity of the samples even after being stored for three weeks at 0° C., 25° C. and 50° C. remained in the range of 10-13 cps. Such results indicate that the polymer blends prepared in Examples 1-6 are storage stable. The pH remained constant during the storage period.
EXAMPLE 9
In this example, an aqueous 70/30 weight percent blend of Sulfo-Polyester C and an acrylic resin was prepared using temperature conditions that fall outside the range acceptable to the process of the present invention. The acrylic resin solution was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 682 ® Flakes 175.0 30.0Ammonium Hydroxide (28% soln.) 44.0 7.5Water 364.0 62.5______________________________________
The following procedure was used for preparing the blend:
1. Water and NH 4 OH were combined to form an alkaline solution. Joncryl 682® flakes were added to the alkaline solution while stirring was applied to form an acrylic resin solution.
2. Excess ammonia was removed from the acrylic resin solution by heating the solution to 70°-80° C. while continuously stirring the solution. The solution was allowed to cool to 25° C.
3. Sulfo-Polyester C which is in the form of a 28% dispersion was prepared.
4. The acrylic polymer solution of Step (2) was added to the Sulfo-Polyester C dispersion with agitation.
The polymer blend gelled within 24 hours.
EXAMPLE 10
Water-based inks were prepared using the polymer blends of Examples 1-6. The composition of the water-based inks were as follows:
______________________________________INGREDIENTS (wt %)______________________________________Blue Pigment (PV Fast Blue B2G-A) Millbase 10.0Polymer Blends (Examples 1-6) 75.0Water 15.0______________________________________
The water-based ink samples were applied to aluminum foil, polyester film and coated paper with Nos. 3 and 6 Meyer rods. The samples were either allowed to dry for 24 hours at 25° C. or were dried in an oven at 100° C. for three seconds. Water resistance of the samples was determined by a water spot test wherein distilled water drops were left for 5, 10, 15 and 20 minutes and then wiped off gently with a tissue. The integrity of the ink films was visually assessed and rated as follows:
Poor: Total film removed
Fair: Partial film removed
Good: Dull or discolored film, but no removal
Excellent: The film was substantially unchanged
The effect of water drops on the water-based ink films prepared using the polymer blends of Examples 1-6 resulted in dull or discolored film but no removal. The films, therefore, achieved a rating of "Good".
EXAMPLE 11
The water-based ink samples prepared in accordance with Example 10 were tested to determine blocking resistance. The water-based ink samples were applied to aluminum foil, polyester film and coated paper with Nos. 3 and 6 Meyer rods. The samples were evaluated for blocking temperature using a PI Sentinel Heat Sealer at 40 psi for five seconds. Blocking temperature is the highest temperature at which the printed ink retains blocking resistance. The samples were folded such that the printed surface was face-to-face. The folded samples were placed under the PI Sentinel Sealer at different temperatures until blocking occurred. The blocking resistance of the ink films was visually assessed and rated as follows:
Poor: Picked and complete film removed
Fair: Picked, but partial film removed
Good: Slightly picked, but no film removed
Excellent: No picking and no film removed
The blocking temperature was in the range of 140°-160° F. for the water based ink films prepared using the polymer blends of Examples 1-6. The films, therefore, achieved a rating of "Good".
EXAMPLE 12
This example is similar to Example 5 except that Sulfo-Polyester B was substituted for Sulfo-Polyester C. The polymer blend was prepared using the following ingredients:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Joncryl 683 ® Flakes 150.0 14.29Sulfo-Polyester B 150.0 14.29NH.sub.4 OH (28% soln.) 37.5 3.57Water 712.5 67.85______________________________________
The polymer blend has a solids content of 31.6%. The blend was not stable and separated into two phases.
EXAMPLE 13
Example 12 was repeated except that Sulfo-Polyester A was substituted for Sulfo-Polyester B. The blend was not stable, and separated into two phases.
EXAMPLE 14
This example demonstrates the use of Sulfo-Polyester C/acrylic resin blends in pigment grinding to prepare ink millbases. The following ingredients were used for grinding pigments:
______________________________________ AMOUNTINGREDIENTS (grams) (wt %)______________________________________Polyester C/Joncryl 683 ® Blend 250.0 50.0Blue Pigment PV Fast Blue B2G-A 125.0 25.0Water 125.0 25.0______________________________________
Millbase was prepared by adding pigment to the diluted polymer blend. The mixture was shaken using equal weight of glass beads for four hours on a paint shaker. The millbase was filtered using cheese cloth. The millbase was stored in a plastic/glass container. The average particle size of the pigment in the millbase was about 2.0 μm as measured by light scattering method. The gloss of the film on coated paper ranged between 20-30 at 60° C.
Many variations will suggest themselves to those skilled in this art in light of the above detailed description. All such obvious modifications are within the full intended scope of the appended claims.
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This invention relates to a process for preparing aqueous blends of sulfo-polyesters and solid acrylic resins without volatile organic compounds (VOC's) and surfactants. More specifically, the acrylic resins are characterized by an inverse relationship between the molecular weight and acid number of the resin, and the sulfo-polyesters contain at least 12 mole percent of a difunctional sulfomonomer. The aqueous sulfo-polyester/acrylic resin blends of the present invention are useful in inks, overprint varnishes, primers, paints, and coatings.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Japanese Patent Application P 2002-324135, filed Nov. 7, 2002 in the Japanese Patent Office, the disclosure of which is incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method for fabricating a through-hole interconnection substrate and a through-hole interconnection substrate. More specifically, the present invention is adapted for a high-density three-dimensional packaging of stacking a silicon IC chip and the like or to a contact thereof. The present invention is also adapted for a silicon optical bench for implementing an optical device such as a laser diode, a photodiode and an optical waveguide.
[0004] According to the present invention, a metal for a conductor is filled in micro-holes for through-hole electrodes. The through hole electrodes are utilized for interconnecting wiring patterns formed on front and back surfaces of a silicon substrate, to be employed as electrodes or contacts, and to form bumps.
[0005] 2. Description of the Related Art
[0006] An example of a related art technology for filling metal in micro-holes is a moltenmetal suction method disclosed in Japanese Patent Laid-Open No. 2002-158191. According to this method, a molten metal is filled in the holes by means of a pressure difference. An example of a method for forming bumps on one surface of a substrate simultaneously with this filling work, is one in which metal layers are formed in the peripheries of openings of the micro-holes, followed by the metal filling by the molten-metal suction method.
[0007] In the molten-metal suction method, heat sometimes deteriorates adhesion of a heatresistant sheet, thus making it impossible to fill the metal fully in the ends of the micro-holes.
[0008] Specifically, when the melting temperature of the metal material in use exceeds 350° C. (degrees centigrade) during the filling work, such high temperature is beyond a tolerance of the heat-resistant sheet.
SUMMARY OF THE INVENTION
[0009] In order to solve the above problems, a first aspect of the invention is directed to a method for fabricating a through-hole interconnection substrate. The method includes forming a blind hole in a substrate from a first side of the substrate toward a second side of the substrate, forming a conductor in the blind hole, and removing a portion of the substrate from the second side of the substrate to expose an end of the conductor.
[0010] The conductor may be molten and pressurized into the blind hole.
[0011] The method may include the step of forming an insulated layer on a surface of the substrate and an inner wall of the blind hole.
[0012] The substrate may be etched from the opposite side.
[0013] A second aspect of the invention is directed to a through-hole interconnection substrate. The through-hole interconnection substrate includes a substrate having a through-hole and a conductor protruding through the through-hole. The substrate is formed with a blind hole extending from a first side of the substrate toward a second side of the substrate, the conductor is formed in the blind hole by pressurizing molten conductor material, and a portion of the substrate and an end portion of the conductor are removed from the second side of the substrate, exposing the conductor filled in the blind hole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above and other aspects and advantages of the invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:
[0015] [0015]FIG. 1 is an exploded perspective view of a three-dimensional multilayer device.
[0016] [0016]FIGS. 2A to 2 E are cross-sectional views of an exemplary embodiment of an insulator substrate according to the invention, showing steps of forming through-hole interconnections.
[0017] [0017]FIGS. 3A to 3 D are cross-sectional views of an exemplary embodiment of a semiconductor substrate according to the invention, showing steps of forming through-hole interconnections.
[0018] [0018]FIGS. 4A to 4 E are cross-sectional views of the semiconductor substrate, showing steps following FIG. 3D.
[0019] [0019]FIGS. 5A to 5 C are schematic views showing steps of a molten-metal suction method.
[0020] [0020]FIG. 6A is a schematic view of an apparatus for use in photo assisted electro-chemical etching.
[0021] [0021]FIG. 6B is a schematic view showing a principle of the photo assisted electrochemical etching.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0022] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. The described exemplary embodiments are intended to assist the understanding of the invention, and are not intended to limit the scope of the invention in any way.
[0023] Referring to FIG. 1, a multilayer device 100 includes IC (Integrated Circuit) chips 101 , 102 , and 103 as three stacked layers. Multilayer device 100 includes a sensor chip 104 on IC chip 103 . IC chips 101 , 102 , and 103 include through-hole interconnections 101 a , 102 a , and 103 a in peripheral edges thereof, respectively. Through-hole interconnections 101 a , 102 a and 103 a electrically connect IC chips 101 , 102 and 103 with each other. Sensor chip 104 includes gas sensor 104 a , pressure sensor 104 b , and IR sensor 104 c on a surface thereoL
[0024] A method for fabricating multilayer device 100 includes the steps of processing a work, forming a circuit pattern, and bonding a wire. The work is processed as below.
[0025] Fabrication of a work or a through-hole interconnection substrate of an insulated material will be described with reference to FIGS. 2A to 2 E (the case where the work is a substrate is assumed in the description below).
[0026] The work is fabricated by the steps of forming blind holes (refer to FIG. 2A), forming metal layers (refer to FIG. 2B), and filling molten metal (FIGS. 2C and 2D).
[0027] Referring to FIG. 2A, a plurality of micro-holes 3 are formed on one surface 5 of a glass substrate 1 . Micro-holes 3 are made blind. Thickness T of glass substrate 1 is larger than depth D of each micro-hole 3 from one surface 5 .
[0028] For example, a DRIE (Deep Reactive Ion Etching) method, a laser method, a micro drill method or a sandblast method may be applied to form micro-holes 3 . The DRIE is an ICP-RIE (Inductively Coupled Plasma-Reactive Ion Etching) method. The laser method employs a laser for drilling. The micro drill method employs a micro drill (micro diameter drill) for drilling. In the sandblast method, micropowder is sprayed.
[0029] Additionally, the substrate is not limited to glass substrate 1 . For example, a ceramic, a resin or a composite material thereof is also applicable as long as it has heat resistance higher than a melting temperature of a metal to be filled therein. The thickness of the substrate is on the order of several ten micrometers (μm) to several centimeters (cm). The diameter and depth of each micro-hole are on the order of several nanometers (nm) to several millimeters (mm). There are no limitations in the number of micro-holes to be formed on the substrate.
[0030] Referring to FIG. 2B, metal layers 7 are formed in the peripheries of openings of the plurality of micro-holes 3 , for example, by sputtering, and are patterned into a predetermined shape. The shape of metal layers 7 is predetermined to assist in the formation of a bump shape (described below). An example of the metal layer (underlayer) is a layer of Cr and then Au sputtered with thicknesses of 30 nm and 500 nm, respectively. After coating photoresist thereon, the resist is patterned by photolithography. The Au and then the Cr are etched by use of the patterned resist as a mask.
[0031] Referring to FIGS. 2C and 5A, a molten-metal bath 67 and substrate 1 are disposed in a chamber 51 . Substrate 1 is supported by substrate holder 55 . A molten metal 11 is stored in bath 67 . Molten metal 11 is a gold-tin eutectic solder (Au—20 wt % Sn). Molten metal 11 is heated up, for example, to 330° C. to be molten by a heater 65 . The atmospheric pressure in chamber 51 is reduced to vacuum. Next, referring to FIG. 5B, substrate 1 is immersed in molten metal 63 in bath 67 . At this stage, molten metal 63 is not filled in micro-holes 3 . Next, referring to FIG. 5C, after substrate 1 reaches a temperature substantially equal to that of molten metal 63 , chamber 51 is pressurized, for example, to the atmospheric pressure or higher. This pressurization fills molten metal 63 into micro-holes 3 . Subsequently, substrate 1 is raised from bath 67 . At this time, bumps are formed on micro-holes 3 .
[0032] Glass substrate 1 formed by the above process corresponds to FIG. 2D. Molten metal 11 has been filled and is solidified inside the plurality of micro-holes 3 of substrate 1 , forming blind contacts 13 . The formation of metal layers 7 also forms bumps 15 .
[0033] Referring to FIG. 2E, the opposite surface (bottom surface) 17 of glass substrate 1 is then ground and polished off for flattening. The grinding and polishing allow the bottom surfaces of the filled metal to appear. Thus, contacts 13 are exposed from glass material Ma. Specifically, glass substrate 1 including through-hole interconnections 13 and bumps 15 is completed.
[0034] Next, the steps of forming micro-holes in a substrate made of a material other than the insulated material will be described.
[0035] Referring to FIG. 3A, a plurality of micro-holes 23 are formed on one surface 25 of a silicon substrate 21 . In this case, micro-holes 23 are made blind. A thickness T 2 of silicon substrate 21 is larger than a depth D 2 of each micro-hole 23 from one surface 25 .
[0036] To the formation of holes 23 , for example, the Photo Assisted Electro-Chemical Etching (hereinafter, referred to as a PAECE method) is applied. In the PAECE, an aqueous hydrofluoric acid (HF) solution is brought into contact with the front surface of an n-type silicon substrate, and lights of a xenon lamp are irradiated onto the back surface thereof. The silicon substrate functions as an anode. A platinum plate in the aqueous hydrofluoric acid solution functions as a cathode. A voltage is applied between the silicon substrate and the platinum plate.
[0037] Specifically, referring to FIG. 6A, an apparatus 70 includes electrolytic bath 71 storing electrolyte 72 of the HF solution. Apparatus 70 includes a cathode electrode 73 immersed in the electrolyte, and silicon substrate 21 . Apparatus 70 includes a DC power 74 between silicon substrate 21 and cathode electrode 73 . Apparatus 70 includes a light source 75 placed outside an electrolytic bath 71 . Apparatus 70 includes an infrared filter 76 between electrolytic bath 71 and light source 75 .
[0038] On surface 21 b of the silicon substrate, a V-groove 21 a is formed by use of KOH in advance. Lights are radiated from light source 75 , pass through filter 76 , and are irradiated onto back surface 21 c of the silicon substrate, which coincides with V-groove 21 a . During this irradiation, current flows between substrate 21 and electrode 73 .
[0039] Referring to FIG. 6B, V-groove 21 a is selectively etched to form a hole. Specifically, by the irradiation of lights 75 a onto back surface 21 a of the silicon substrate, carriers (positive holes) are produced on back surface 21 c . These carriers concentrate on the tip end of the bottom of V-groove 21 a , and the tip end is intensively etched.
[0040] The substrate is not limited to silicon substrate 21 . The substrate may be made of, for example, a chemical compound, a semiconductor or a metal, as long as it has heat resistance greater than the melting temperature of the metal to be filled therein. The thickness of the substrate is the order of several ten micrometers to several centimeters. The diameter and depth of each micro-hole are the orders of several nanometers to several millimeters. There are no limitations in the number of micro-holes to be formed on the substrate.
[0041] A DRIE method, a laser method, a micro drill method or a sandblast method may be applied to a substrate of a non-insulated material in place of the PAECE method.
[0042] Referring to FIG. 3B, an insulated layer 27 is formed on the inner walls of microholes 23 and the surface of the substrate. For example, a SiO 2 film, a SiN film or the like is formed by use of a method such as thermal oxidization, CVD or coating of a spin-on-glass film. The thickness of insulated layer 27 is the order of several ten nanometers to several millimeters.
[0043] Next, referring to FIG. 3C, metal layers 29 are formed by sputtering in the peripheries of openings of micro-holes 23 , and patterned into a predetermined shape. The shape of metal layers 29 is predetermined to assist in the formation of a bump shape (described below). An example of the metal layer (underlayer) is a layer of Cr and then Au sputtered with thicknesses of 30 nm and 500 nm, respectively. After coating photoresist thereon, the resist is patterned by photolithography. The Au and then the Cr are etched by use of the patterned resist as a mask.
[0044] Referring to FIG. 3D, a molten metal 33 is filled in micro-holes 23 of silicon substrate 21 by the molten-metal suction method. Subsequently, substrate 21 is raised from the molten metal bath 67 . At this time, bumps 37 (refer to FIG. 4A) are formed on micro-holes 23 .
[0045] Silicon substrate 21 after the process will be described with reference to FIG. 4A. Molten metal 33 has been filled in the plurality of micro-holes 23 , and formed the plurality of contacts 35 . Bumps 37 are formed on metal layers 29 . As described above, the surface of silicon substrate 21 is covered with insulated layer 27 .
[0046] Referring to FIG. 4B, the opposite surface (bottom surface) 39 of silicon substrate 21 is ground and polished. The grinding and polishing are stopped back from insulated layer 27 formed in micro-holes 23 . Thickness T3 of silicon substrate 21 is larger than depth D3 of each micro-hole 23 on which insulated layer 27 is provided and in which molten metal 33 is filled.
[0047] Referring to FIG. 4C, only the substrate material is etched, for example, by chemical etching. This etching allows the bottom portions of the micro-holes (that is, contacts 35 as filled metal covered with the insulated layer) to appear in the order of several micrometers. Plate thickness T4 of silicon substrate 21 is made smaller than length D4 of each contact 35 . The bottom portions of the micro-holes may be exposed from the start only by, for example, the chemical etching, without grinding and polishing, other than in the method described above.
[0048] Referring to FIG. 4D, an insulated layer 41 is formed on the surface of the exposed substrate material. A process temperature during the formation of the insulated layer 41 is set at a temperature lower than a melting point of the filled metal. This set temperature prevents the filled metal from melting and falling out of micro-holes 23 during the operation. There are no limitations on the material of insulated layer 41 , except that it must be possible to form insulated layer 41 at a process temperature lower than the melting point. The thickness of insulated layer 41 is the order of several micrometers to several ten micrometers.
[0049] Specifically, if the filled metal is gold-tin eutectic solder (Au—20 wt % Sn) with the melting point of 280° C., a SiO 2 film with a thickness of 5 μm is deposited at 200° C. by plasma CVD. Again, the opposite surface (bottom surface) 39 of the substrate is ground and polished, exposing the bottoms of the metal-filled portions. Thus, the through-hole interconnections are completed.
[0050] Silicon substrate 21 after the process will be described with reference to FIG. 4E. The surfaces of material Mb of silicon substrate 21 is covered with insulated layer 27 and insulated layer 41 . Contacts 35 with bumps 37 made of metal layers 29 are formed. The surface of the substrate material is covered with the insulated layer, and there is no potential risk that the filled metal would contaminate the substrate material.
[0051] Thus, according to an aspect of the invention, a substrate is formed with a blind hole. Next, the inner wall of the hole and the surface of the substrate are formed with an insulated material, except in the case of a substrate formed of an insulated material. A metal layer is formed around an opening of the hole. A molten-metal suction method is employed to fill a metal in the hole and to form a bump.
[0052] Thus, according to the method, the sealing of the hole on one side by the substrate itself requires no heat-resistant sheet, and allows sealing not to be broken by heat.
[0053] In a case of a substrate of an insulated material, after filling a metal, the bottom surface is ground and polished to expose a filled metal. This completes a through-hole interconnection.
[0054] Next, in a case of a substrate without an insulated material, after filling a metal, the bottom surface is ground and polished in the same manner. However, the grinding and polishing are stopped back from the insulated layer formed in a micro-hole. Thereafter, only a substrate material is etched, using, for example, chemical etching, exposing the bottom of the micro-hole. The insulated layer at the bottom of the micro-hole is employed as a protection layer against etching. The reason not to grind and polish the filled metal in the micro-hole is to prevent the attaching or dispersing of a metal powder to or in the substrate material and the resulting contamination of the substrate. In a case of a substrate of a single crystal, for example, chemical etching after grinding and polishing can remove a fractured layer on the polished surface that is produced by grinding and polishing. This effectively removes defects such as micro-cracks on the surface of the substrate.
[0055] Next, an insulated layer is formed on the exposed surface of the substrate. A process temperature during the formation of the insulated layer is set at a temperature less than melting point of the filled metal. This prevents the filled metal from melting and flowing out during the operation. Thereafter, again, the bottom of the substrate is ground and polished to expose a metal filled portion. This completes a through-hole interconnection. The surface of the substrate is covered with an insulated layer, and no contamination due to the filled metal occurs.
[0056] Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art, in light of the above teachings. The scope of the invention is defined with reference to the following claims.
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A blind hole ( 3 ) is formed on a substrate ( 1 ) from a first side of the substrate toward a second side of the substrate ( 1 ). A conductor ( 11 ) is filled in the blind hole ( 3 ). The substrate ( 1 ) is removed from the opposite side to expose the conductor ( 13 ) filled in the blind hole ( 3 ).
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FIELD OF INVENTION
This invention relates to sewage disposal systems and more particularly to effluent flow controller.
BACKGROUND OF INVENTION
In the past, the absorption field or subsurface tile structure of septic tank and sanitation systems has consisted of a field of 12 inch lengths of four inch architectural drain tile, 2 to 3 foot lengths of vertured clay sewer pipe, or extended lengths of perforated, non-metallic pipe. These fields are laid in such a manner that the effluent flow from the septic tank is distributed with reasonable uniformity to the ambit soil.
It is considered essential to have a distribution box or similar means in each absorption field to divert the effluent into separate pipe systems. In other words, the purpose of the box or junction is to insure equal distribution of the effluent from the septic tank into the various lateral lines. The main purpose of the junction is to prevent overloading and thus failure of one of the lines while the other line or lines are left empty.
Plain pipe fittings in the form of T's and Y's have been proposed to replace distribution boxes but they have been found not to give even distribution. Even using distribution boxes, the same must be installed in a perfectly level condition or more effluent will move into one line than the other thus causing the problems outlined above.
One earlier solution to the above-indicated problems was the present invention Distribution Means disclosed in U.S. Pat. No. 3,497,067, where a distribution box or modified T included a flow divider with a knife edge which, even though the box or joint was not level, would allow the flow of effluent to still be almost evenly divided into each of the different distribution lines.
Although the above system has proved successful in commercial use, there can still be a buildup of solid particles on or around the knife edge of the divider, particularly when the effluent is moving slowly, and can, if not eliminated, eventually cause uneven flow and defeat the purpose of the system.
SUMMARY OF THE INVENTION
After much research and study into the above-mentioned problems, the present invention has been developed to provide an improved distribution means for septic tank effluents which not only divides the effluent flow but also prevents the buildup of solids on the divider means. This is accomplished through the provision of a relatively steep knife edge beginning at an overhanging lip and extending downwardly to a second angular knife edge at the lower end thereof.
All large flows of effluent begin and end with small, slow amounts of flow. It is during this slow flow that small particles may become lodged on or adjacent the prior art flow divider and begin to build up. By having the overhanging lip adjacent the divider knife edge, even a small, slow flow, as it drops off the lip, will increase in speed thus preventing particle lodging and buildup. Also any buildup that does occur on the knife edge will eventually be washed by the heavier flows down the knife edge and from continued heavy flow pressure, will be cut by the second or angular knife edge and washed to either side thereof.
In view of the above, it is an object of the present invention to provide a distribution means for septic tank effluent which assures that undesirable buildup of solids does not occur on the flow dividing means.
Another object of the present invention is to provide an improved distribution means for septic tank and similar effluents which includes a double knife edge separating means.
Another object of the present invention is to provide a simple, relatively inexpensive, and yet highly efficient improved flow distribution means.
Another object of the present invention is to provide a simple, inexpensive, and yet highly efficient flow divider which is self-cleaning.
Another object of the present invention is to provide, in a flow dividing distribution system, an overhanging lip with adjacent knife edges for preventing buildup of solid particles.
Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention.
BRIEF DESCRIPTION OF FIGURES
FIG. 1 is a cutaway perspective view of a typical prior art septic tank distribution box and absorption field.
FIG. 2 is a side elevational view of the improved distribution means of the present invention; and
FIG. 3 is a partially cutaway perspective view thereof.
DETAILED DESCRIPTION OF INVENTION
With further reference to the drawings, a typical prior art septic tank sewage disposal system is shown in FIG. 1 including an inlet line 10 from the house or other structure, a septic tank 11, a connector line 12 between said septic tank 11 and distribution box 13. Finally, distribution lines 14 lead from the distribution box to the absorption field 15.
In the above described prior art system, the distribution box 13 has an open interior and, therefore, must be disposed absolutely level on a solid foundation that will not settle. If this is not accomplished, complete failure of the system will rapidly develop due to all of the septic tank effluent passing into one of the distribution lines, to the exclusion of the other, as a result of the natural phenomenon of liquids seeking their lowest level. Even when using the distribution system disclosed in U.S. Pat. No. 3,497,067 with a central partition and generally curved knife edge, problems can develop due to buildup of slow moving solid particles in the effluent.
The present invention, indicated generally at 16, can be used in conjunction with the usual inlet line 10 from the house or other structure, the standard septic tank 11, and the associated connector line 12. A coupling sleeve 17 is used to communicatively connect line 12 to the present invention. Coupling sleeves of the type shown are well known to those skilled in the art and further detailed discussion of the same is not deemed necessary.
The inlet portion 18 of the present invention is effectively a continuation of the connector line 12 through coupling sleeve 17. An end cap 19 is used to seal the open end inlet portion 18. A clean-out opening 20 is provided in the upper portion of inlet 18 and a clean-out cover 21, formed from a plastic or similar material having a memory, is adapted to be snapped thereover as shown in FIGS. 2 and 3.
The distribution portion 22 of the present invention is notched into the inlet portion 18 with such portions being fused, welded, glued, cemented or otherwise secured to each other. A transverse opening 23 is provided in the lower portion of inlet 18 and, when viewed from the side as shown in FIG. 2, is slightly smaller in diameter than the interior diameter of the distribution portion 22. This forms a lip or overhang 24 at the throat 25 of the present invention which is defined as the juncture between the flow divider partition 26 and inlet portion 18.
The flow divider partition 26 is formed from a relatively thin material and includes a primary knife edge 27 which is rather steeply sloped downwardly from throat 25. A secondary knife edge 28 is formed in partition 26 at a slightly obtuse angle to the primary knife edge 27 as can clearly be seen in FIG. 2.
Although the improved distribution means of the present invention can be constructed from various types of metals, concrete, or the like, standard PVC type materials presently used in the plumbing industry have been found to be easy to work with and to stand up well under all types of weather and use conditions.
When it is desired to use the improved distribution means 16 of the present invention, the inlet portion 18 thereof is aligningly abutted against line 12 coming from septic tank 11 and sleeve 17 is slipped over the joint. A sealer such as PVC cement can then be used to permanently join line 12 with inlet portion 18. The distribution portion 20 of the present invention should always be disposed horizontally or as close to horizontally as possible. This is not always absolutely possible, however, and certainly the shifting of the soil thereunder can throw the same out of horizontal alignment as is encountered with the prior art distribution systems.
Once the distribution portion has been horizontally aligned, connector sleeves 29 can be slipped over the ends thereof and used to secure the same to distribution lines 14 leading into the absorption field 15. The clean-out cover 21 is then snapped over clean-out opening 20. All of the lines, tanks, distribution means, etc. can then be covered with dirt and the system is ready for use.
Whenever toilets are flushed, showers are taken, or the liquids are introduced into the full septic tank 11, treated effluent will be forced therefrom in equal amounts and at equal flow rates. At the beginning and end of each flow, there is slow movement which tends to allow any small particles in the effluent to settle. In normal flow lines, the next heavy flow will wash such particles on but they can and do build up on in any obstructions encountered. As the slow-moving effluent flow and the particles being carried thereby reach the throat area 25 of the present invention, such flow and its particles fall from lip 24 thus increasing the speed, whether it be a stream flow or a drip flow.
Further, any particles which happen to be lined up with the primary knife edge 27 of the flow divider partition 26, when they come into contact with such knife edge, will tend to be carried downwardly by the downwardly disposed angle of the same thus throwing such particles to one side of the partition or the other. Also, the next time a relatively heavy flow is introduced into the improved distribution means of the present invention from connector line 12, any particles lodged on the knife edge will be washed therefrom.
Should larger effluent solids or an accumulation of solids build up on the primary knife edge 27, they will be washed by the force of the heavier flows of effluent down such primary knife edge to its juncture with the secondary knife edge 28. This knife edge is set only a few degrees off perpendicular to the heavier effluent flows which will press the accumulated particles or solids against such secondary knife edge thereby effectively cutting the same into and with the help of the heavier effluent flow, wash the same to one side or the other of partition 26. Thus it can be seen that the flow divider partition 26 and its associated knife edges 27 and 28 are effectively self-cleaning.
From the above it can be seen that the present invention has the advantage of providing an improved distribution means which is relatively inexpensive to manufacture, is highly efficient in dividing effluent flows into distribution lines, and is effectively self-cleaning.
The present invention can, of course, be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
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This invention is an improved distribution joint used in conjunction with septic tank absorption field systems. The invention more particularly divides and accurately controls the distribution of septic tank effluent into separate portions of the absorption fields while eliminating the buildup of flow disrupting sediment on the divider by providing a unique flow pattern thereover.
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BACKGROUND OF THE INVENTION
The present invention refers to a clothes washing machine, in particular a household-type clothes washing machine, provided with special means and related operating modes to enable the particular type of textiles, or mix thereof, forming the washload in the drum of said washing machine to be appropriately identified.
Although the present invention relates particularly to front-loading clothes washing machines, and for reasons of greater simplicity and convenience the following description refers to such a type of washing machines, it will be appreciated that the invention may similarly apply to other types of washing machines, such as top-loading washing machines.
Washing machines are known in the art that are provided with means adapted to identify the type of textiles, or mix thereof, forming the particular washload being handled in the drum of the washing machine. A purpose of such identification is to provide the machine with the ability of selecting the washing cycle automatically, with the various process parameters selected so as to optimize the operation of the machine and the washing results. For instance, the U.S. Pat. No. 5,161,393 to the name of General Electric Company discloses a quite effective method for identifying the type of textiles in the washload. However, such a method only applies to washing machines having their drum rotating about a vertical axis, so that it is not suitable for use in conjunction with the great majority of washing machines having their drum rotating about a horizontal axis, that is, nearly all of the European-built machines. Furthermore, such a method is a sort of a trial-and-error one based on a set of successive measurements, so that it is quite complex and time-consuming.
SUMMARY OF THE INVENTION
It would therefore be desirable, and is in fact a main purpose of the present invention, to provide a clothes washing machine that has a drum rotating about a horizontal axis and is, nevertheless, capable of performing the measurements required to identify the type of textiles in the washload by using safe, reliable, inexpensive methods and means on the basis of readily available technologies.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a first arrangement of component parts and levels of a clothes washing machine according to the present invention;
FIG. 2 is a graph illustrating diagrammatically the water absorption capacity of textiles of different nature;
FIG. 3 is a graph illustrating water level vs. time, with the machine drum both at a standstill and rotating, for different types of textiles;
FIG. 4 is a schematic view of a second arrangement of component parts and levels of a clothes washing machine according to the present invention;
FIG. 5 is a graph illustrating diagrammatically the evolution of the level of the water measured in a clothes washing machine according to the present invention as a function of the progression of the washing cycle, for a low-absorbing type of textile; and
FIG. 6 is a view of a similar diagram as the one shown in FIG. 5, but referring to a highly absorbing type of textiles, all other conditions being the same.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The term "water" will be used in the following description to mean both washing liquor and rinsing water. Such a simplification, however, will by no means affect the clarity of the disclosure considering the context in which such terms are being used, as anyone skilled in the art will be able to readily understand.
Referring now to FIG. 1, which illustrates a preferred embodiment of the present invention, a solution according to the present invention is explained along with the related operation principles.
The described clothes washing machine comprises a washing tub 1, a drum 2 rotating inside said washing tub and adapted to hold the washload, and a pressure switch 3 having an air intake 4 situated at a position below the lower edge 5 of the washing tub. The clothes washing machine is further provided with programming and controlling means, including control means 6, such as an electromagnetic valve, for opening and closing the water supply from an external source. A recirculation circuit (not shown) is provided for recirculating the water contained in the tub, the recirculation circuit being adapted to be selectively activated by said programming and controlling means of the machine and to take up the water from the bottom of the tub and let the water flow back into or onto the drum so that all washload items contained in said drum are, in as short a time as possible, affected simultaneously by said flow of recirculated water.
Textile items to be washed are largely known to have water soaking characteristics that can vary to a very large extent according to the particular nature of their fiber material and the manner in which the material has been processed. It is also a commonly known fact that water soaking characteristics are most marked in items made of sponge-cloth, whereas soaking characteristics are less marked in cottons and/or fabrics made of man-made fibers. The term "soaking" is used here to mean the amount of liquor taken up by the cloth before saturation, that is, before any further liquor added starts to be released. This technical term, like some other terms used here, is a part of the common knowledge of those skilled in the art and, as such, it is assumed to be commonly known.
The present invention therefore consists substantially in filling a definite amount of water into the tub, including also all possible cavities associated therewith, such as for instance an outlet pipe, an airtrap of the pressure switch and the like. Then the clothes are soaked as much as possible by said water, possibly by subsequently filling in additional amounts of water as needed to restore the water level. The amount of residual water is measured after the clothes have been soaked to saturation. Finally, based on the weight of the clothes loaded into the drum and the amount of water absorbed, the average soaking characteristic of the washload is calculated and, hence, the mix of textile types in the washload is determined.
Identifying the mix of textile types included in the washload on the basis of their water absorption capacity and, of course, the respective weight is an experimentally viable technique that is widely known in the art, so that no further explanation will be given here in this connection.
The diagram appearing in FIG. 2 represents on the ordinate the amounts, in liters, of water absorbed by several types of fabrics the weights of which are plotted on the abscissa, wherein the upper curve A refers to sponge-cloth, while the lower curve C refers to cotton and synthetics.
Since the nature of the fabrics, which is not known, is identified on the basis of the capacity thereof to absorb water, it proves necessary that a pre-determined amount of water be filled into the tub, and the related level be checked, after allowing the fabrics being tested to attain their highest inherent soaking points by letting the drum rotate a certain number of times at a low speed with the recirculation circuit operating normally, so that all textile material can be wetted and, therefore, absorb water.
It is, however, necessary that the amount of water to be filled be defined and such an amount may be an arbitrary value. What really matters is the percentage of water absorbed after agitating or rotating so as to enable each type of fabric to attain its highest possible soaking point. There is only one limitation in this connection, said arbitrary value shall in any case lie between the highest and lowest theoretically possible water absorption values (curves A and C).
At this point the machine, upon being given a further command or by acquiring it directly in some other manner, which is not a part of the present invention, acquires information concerning the weight of the washload introduced in the drum.
A water fill curve B is then selected that is exactly intermediate with respect to both above-mentioned extreme curves and, therefore, corresponds to a hypothetical washload formed by both sponge-cloth and cotton fabrics on a fifty-fifty weight-percent basis.
As a result, the washing machine fills in the amount of water corresponding to the total weight of the washload as detected directly or fed as an input into the programming system by suitable means. For instance, 12.5 liters of water would be filled in for a washload with a total weight of 3 kg, as shown in FIG. 2.
Upon completion of this phase, the programming system controls the machine so as to cause the drum to complete a number of rotations and the recirculation circuit to be activated until all of the textile material in the washload has the opportunity of being wetted and absorbing water. In the case that the water is in excess, excess water is released. As a result, with reference to FIG. 1, the level of the water in the tub will shift from the original level L1 to a new level L2, which is duly detected by the pressure switch 3.
At this point, the programming and control system of the machine, which will have been appropriately programmed and supplied with all necessary data, identifies and automatically expresses the average soaking value of the fabrics being tested and, hence, the type of fabrics, or mix of fabrics, having a behavior corresponding to the soaking value detected.
It may be observed that, when the water is being filled in up to its normal level, the water touches and penetrates the walls of the drum and is absorbed by the clothes, thereby generating a measurement error which is proportional to the washload and its overall water absorption capacity.
Such an error induces a flow rate to be calculated which is quite often smaller than the actual flow rate. It therefore ensues that time-controlled water filling is almost invariably wrong, in that more water is filled than actually needed. However, such a slight error can be easily compensated by an appropriate correction of the calculation means based on the behavior determined experimentally.
A variation of the aforedescribed procedure consists in filling an excessive amount of water, for a given weight of the washload, so as to fully soak any possible type of fabric.
With reference to FIG. 3, the curve indicates the water level in the tub, with the drum at a standstill, as a function of the inflow time (on the abscissa) of water from outside for a certain total weight of the washload. A step can be noticed in this curve which corresponds to the moment at which the level reaches up to the lower edge of the drum, and the points A, B and C along the curve correspond to respective types of fabrics or mix of fabrics, according to the aforegiven definitions. The point K corresponds to the level of excess water selected for any type of fabric and referred to a respective weight of the washload.
By causing the drum to start rotating and the recirculation pump to start operating, the level defined by the water level falls according to the water absorption by the clothes. From point K, a plurality of curves are defined. Among these, the curve P defines the changing level for a highly absorbent type of fabric (sponge-cloth), the curve Q gives the same indication for a type of fabric with a medium absorbency (eg. PES/cotton), and the curve R indicates the same for a low-absorbing type of fabric (synthetics).
From the graphs it therefore ensues that, after the level has stabilized, that is, after a pre-determined period of drum rotation and water recirculation, it is possible for the mix of types of fabrics in the washload to be recognized and identified (according to the respective absorption rates) by measuring said level and comparing it with experimental data previously stored in the system, as well as on the basis of the weight of the washload.
In order to better emphasize the behavior of the water level under extreme conditions of the type of fabric in the washload, the two FIGS. 5 and 6 should be closely observed. FIG. 5 illustrates an example of a graph (to be read from right to left) relating to the level of the water as measured in a machine according to the above-described operating mode in which an excess amount of water is filled in and this water is entirely retained by the high-absorbency clothes during a plurality of rotations of the drum under water recirculation conditions. In some phases 30, the level tends to increase and then to correspondingly decrease down to almost nil owing to the instability of the soaking process. Subsequently, the level tends to first increase in a very sharp manner through a certain distance 31 and then slow its rate of increase markedly over a subsequent distance 32, until it substantially stabilizes at a level 33. The same experiment carried out with a low-absorbency type of fabric, as shown in FIG. 6, indicates that the level stays high and substantially stable through a distance 34, in which the rapid variations are indicative of oscillations induced by the rotation of the drum. Then the level increases in a progressive manner, although at a decreasing rate, through a further distance 35, until it eventually stabilizes at a final value 36. The difference between said two stable levels 33 and 36 that, in conjunction with the machine parameters that are already stored in the system and previous experimental data and the actual weight of the washload, enables the mix of types of fabrics in the washload to be calculated (as a function of the respective absorption rates).
A variant form of the aforedescribed methods for measuring and calculating the absorbency characteristics of the fabrics is implemented by making use of the different water retention characteristics of the fabrics after wringing or spinning as compared to the water retention capacity of the same fabrics before wringing or spinning. It has, in fact, been observed experimentally that the accuracy in measuring water retention is usually greater (in the sense of a lesser variability under the same conditions) in the case of spin-extracted clothes with respect to clothes which are only wetted or soaked, but not spin-extracted.
Such a variant consists in carrying through an operating sequence that ensures that all fabrics being tested are entirely wetted and soaked. The fabrics undergo a spin-extraction phase while maintaining such conditions in the tub as to make sure that the level of the free surface of the water is, in all cases, lower than the lowest level of the side wall of the drum (this, of course, in order to ensure the effectiveness of the spin-extraction action). Then, the water absorbed is calculated based on the difference between the total amount of water filled in and the amount of residual water remaining in the tub. The absorbed water is then compared, with reference to the weight of the washload, with previously recorded and stored experimental data relating to a plurality of measurements made on washloads of known weight subjected to a similar spin-extraction process with known contents in terms of mix of types of fabrics.
Based on such a comparison, it is then quite simple to identify, for each weight of the washload, the mix of types of fabrics to be determined.
According to such a variant, the machine goes through a sequence consisting in:
filling into the tub such an amount of water that the level thereof does not exceed the lowest level of the side wall of the drum and storing this amount in a memory of the program controller;
carrying out a plurality of operation sequences, each one of which comprises a plurality of low-speed drum rotation cycles and high-speed drum rotation cycles under simultaneous water recirculation, while recording and storing the level of the water at the end of each sequence of high-speed drum rotation cycles;
carrying out a plurality of level-restoring water additions alternating with said plurality of operation sequences until the level of water measured at the end of said plurality of high-speed drum rotation cycles is equal to or exceeds the previously recorded level, said level-restoring water additions being limited in all cases so as to make sure that the free surface of the water bath in the tub remains constantly below the lowest level of the side wall of the drum;
calculating the amount of water absorbed by the washload in the drum by subtracting the amount of water corresponding to the last recorded level from the total amount of water filled into the tub; and
calculating the "washload-to-absorbed water" ratio and selecting the mix of types of fabrics through a comparison with a previously stored database.
According to such a process, the level tends to stabilize under all circumstances below the original level, owing to the water being absorbed by the clothes. This fact, however, does not cause any problem, since such a case is fully taken into account by the planned operating modalities which provide that, under such a circumstance, the aforedescribed sequence of successive water additions, spin-extractions, measurements and comparisons is carried through or continued.
The above described variant allows for a particularly advantageous improvement in view of accelerating the measurement time requirements. It is, in fact, possible for the minimum amount of water to be filled to be assessed just once, allowing it to be entirely absorbed by the clothes during a low-speed rotation phase of the drum under water recirculation conditions for a few minutes (approx. 3 minutes), then restoring operation according to the aforedescribed modalities starting after the first level-restoring water addition, instead of carrying out a first water fill procedure up to the limit set by the maximum attainable level (side wall of the drum) and then going through an extended sequence of water additions, etc. This variant enables the overall time requirements to be reduced by allowing an amount of water corresponding to several successive water fills and water additions, which would have required a correspondingly longer time to be completed, to be filled in just once, that is, the first time.
A particularly advantageous feature, which is applicable to the cases in which the amount of water to be filled in has to be pre-determined, regardless of the level that can be reached by the water in the tub, is described below.
Such a feature applies for instance to the case of a washload made up of synthetic/cotton fabrics, where the water filled in to soak such fabrics while maintaining, during the subsequent stabilizing cycles, a significant pressure on the filter bell-shaped trap for an appropriately long period of time.
Quite to the contrary, in the case of a washload made up by sponge-cloth fabrics, the same amount of water proves insufficient in view of ensuring a total soaking effect and, therefore, it is absorbed rapidly and entirely under an abrupt fall of the pressure below significant values in a relatively short time, so that it proves impossible to record the new level.
In order to eliminate the drawback of the pressure switch not being able to directly measure the amount of water filled in, it is necessary that the amount of water filled in be accurately measured, regardless of the pressure head existing on the pressure switch.
This can be achieved by letting the water be filled in under time control, once that the flow rate, which depends substantially on both the water inlet means and the water delivery line pressure, is known.
However, for the actual flow rate to be known, considering that it may vary due to a number of factors, among which the water supply pressure from the mains is certainly a very significant one, the following procedure shall be carried out, by first bringing the water level in the conduit up to the level L3 and then defining a second level L4 (see FIG. 4) lying above the level L3 and preferably situated in the outlet conduit in such a manner that the volume V between said levels is known. At this point, the flow-rate measurement sequence is started by switching in the water inlet system and recording the time taken by the water level in said conduit to rise from the level L3 to the level L4. The V-to-time ratio then gives the exact indication of the actual flow rate at which water is filled in.
Once such a flow rate is known, it will be possible for the programming and controlling system of the machine to switch in the water inlet means of the machine just for the time required to let into the tub the exact amount of water needed, with an accuracy which is of course within the tolerances allowed for by the sensitivity of the sensors of the mechanical configuration adopted and the accuracy of calculation arrangement used.
Finally, a measurement error may in some cases be induced by the fact that, during the water filling phase, a part of such water, while flowing down along the wall of the drum, penetrates the same drum where it wets part of the washload. This, of course, brings about an error in the calculation of the flow rate, in the sense that a lower flow rate than the actual one is calculated by the system.
In order to eliminate such a possible error, provisions should be appropriately taken so as to prevent the inflowing water from entering in contact with the clothes contained in the drum. This can be achieved by filling in the water directly from: the lower portion of the tub.
It will be appreciated that anyone skilled in the art is able to identify further solutions and optimizations in the use of the elements and parts associated therewith by relying on techniques and knowledges which are readily available in the art. Therefore, although it has been described using generally known terminology, the present invention should not be considered as being limited by the examples given in this description, since those skilled in the art can add a number of variations and modifications thereto. The appended claims are therefore meant to include any possible, obvious modification that may fall within the common abilities of those skilled in the art.
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A clothes washing machine is provided with a wash tub (1) and a rotating arm (2) accommodated within the wash tub and adapted to contain washload items and capable of being driven so as to rotate both at high and low rotating speeds. A pressure switch (3) is arranged within an appropriate air chamber connected with the intake thereof at a location (4) situated below the lower level (5) of the wash tub. An inlet and shut-off (6) governs the water supply from the water delivery mains to the wash tub. The inlet and shut-off is arranged to detect average soaking characteristics of the washload items placed in the drum by first measuring their overall capacity of absorbing a defined amount of water, and then processing the measured capacity on the basis of the weight of the washload items, the weight being known. The machine operates by letting defined water amounts into the wash tub, wherein the water is allowed to be absorbed by the washload up to the maximum soaking capacity thereof and the amount of absorbed water is then measured at the difference between the amount of water let into the tub and the residual amount of water. Alternatively, the machine operates by performing a substantially similar procedure, except the washload undergoes a spin-extraction phase before the amount of residual water is measured and the calculations are made on the basis of the different water retention characteristics of the spin-extracted washload items.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains to a brake system for a motor vehicle with an actuating device for the individual wheel brakes controlled by the brake pedal; the actuating device, which is connected to the brake pedal through electric lines and which causes brake linings to press against the respective brake disk, is an electromechanical wheel-brake actuator which is mounted on a mount for a brake caliper of the respective wheel brake. The system further includes a sensor disposed at the wheel brake which produces a signal that serves to control the wheel-brake actuator.
2. Description of the Related Art
In conventional motor vehicles, the braking force is controlled by the force exerted by the driver on the brake pedal. Braking interventions by anti-blocking or anti-lock devices, drive-stability control systems, drive-slip control or traction control and the like may be superimposed on this control. This is realized in conventional brake systems (see, for instance, German Patent DE-C 29 54 162) with hydraulic pumps and solenoid valves. In that case, however, the effect of the brake pressure on the braking operation cannot be accurately detected, since the brake-lining/brake-disk and tire/road coefficients of friction are not accurately known. The maximum braking force (adhesion limit) to be absorbed by a tire depends on the state of the tire and in particular on the state of the roadway; it varies within wide limits on a dry or wet roadway surface, in snow, on ice, etc. Since the maximum braking force is not known, the prior art anti-lock systems detect the adhesion limit via an evaluation of the wheel rotary speeds. The evaluation of the wheel rotary speeds and the determination of the adhesion limit is rather time-consuming.
In a published electromechanical vehicle brake (Automobil-technische Zeitschrift, 1996, No. 6, pp. 328-333), the driver's intention is passed via the brake pedal to a master computer which is responsible for the brake management of the entire vehicle. The master computer transmits the driver's intention to the individual brake modules, which set a required wheel braking torque for each individual wheel. Each wheel brake has a brushless electric motor which presses the brake lining against a brake disk via a spindle and is held on the caliper of the disk brake. A spindle nut is driven directly by the rotor of the electric motor. A rotary-position transducer (resolver) supplies an actual value for the engine governing and is used at the same time for the electrical commutation.
A prior art method of controlling the braking effect of hydraulically actuated brakes on aircraft landing wheels utilizes the wheel slip in order to control the braking force. The wheel slip is determined from the rotary speeds of a braked and an unbraked wheel (see German patent publication DE 12 60 324 B). The brake is released after a limit value of the slip is exceeded. In addition, the wheel load, as normal force, and the braking torque (brake moment) are measured, and then the wheel slip, the slip change per unit of time, the braking coefficient, the braking-coefficient change per unit of time, and the ratio of the braking-coefficient change to the slip change are calculated from the above-mentioned variables with the aid of an entire series of computers. The braking torque, which is detected with a torque sensor, enters with many other variables into a very complicated calculation of the ratio of the braking-coefficient change to the slip change, and it is this ratio alone which serves as the actual value for the brake control.
A prior art sensor for braking-force distribution systems and/or anti-lock systems for motor vehicles (German published patent application DE 19 27 282 A) detects the deceleration of the motor vehicle by measuring the stresses or extensions in a part stressed by deceleration forces, for example in the brake caliper of a disk brake or at the fixing point of the brake caliper, specifically with wire strain gauges attached there. Accurate measurement of the elastic extension enables the acting force and thus the deceleration to be deduced. The sensor produces an (actual-value) signal which is a measure of the deceleration of the motor vehicle.
A brake system for a motor vehicle of interest is described in a commonly owned copending application Ser. No. 08/899,748 (filed Jul. 24, 1997). That brake system has an actuating device for the individual wheel brakes which is controlled by the brake pedal via electric lines. The actuating device is designed as an electromechanical wheel-brake actuator which is mounted on the brake caliper of each wheel and by means of which the brake linings are pressed against the respective brake disk.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a TITLE, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which enables a direct measurement of the braking force.
With the foregoing and other objects in view there is provided, in accordance with the invention, a brake system for a motor vehicle with a plurality of wheels and a driver-actuated brake pedal, comprising:
a plurality of individual wheel brakes each for braking a wheel of a motor vehicle, each of the wheel brakes including a brake caliper and brake linings pressing against respective brake disks with a defined contact force for braking the wheels of the motor vehicle;
an electromechanical wheel-brake actuator connected to each of the wheel brakes, the wheel brake actuator being controlled by a brake pedal of the motor vehicle via electric lines;
a force sensor disposed at each of the wheel brakes for directly measuring a circumferential force produced by a brake torque and outputting an output signal; and
a control device connected to and controlling the wheel-brake actuators, the control device receiving the output signal of the force sensor and taking the output signal into account for setting the contact force of the brake linings.
In accordance with an added feature of the invention, there is provided a mount at each of the wheels of the motor vehicle, the wheel-brake actuator and the caliper of each of the wheel brakes being commonly mounted on the mount.
In accordance with an additional feature of the invention, the sensor is mounted at the brake caliper.
In accordance with another feature of the invention, the brake caliper is connected to the mount with a fastening screw or bolt and the force sensor is disposed on the fastening screw.
In accordance with a further feature of the invention, the brake caliper is connected to the mount with two fastening screws and the force sensor includes one force sensor disposed on each of the fastening screws, the fastening screws and the force sensors being arranged behind one another in a circumferential direction of the brake disk, such that a first one of the two force sensors is stressed in tension and a second one of the force sensors is stressed in compression during braking.
In accordance with again a further feature of the invention, the braking force instantaneously exerted on a roadway by the wheel is determined from a difference between the output signals of the two force sensors.
In accordance with a concomitant feature of the invention, the contact force instantaneously exerted on the brake disk by the wheel-brake actuator is determined from a sum of the output signals of the two force sensors.
In summary, the advantages of the invention lie in particular in the fact that the direct measurement of the braking force means that this information is available very quickly and can be evaluated correspondingly quickly in the brake control devices. The braking distance is thus shortened. In addition, due to different coefficients of friction between the brake linings and the brake disk, which, for example, may stem from spray water or from different temperatures of the brake disks, a yaw moment which turns the vehicle out of a direction of travel is produced in the case of conventional hydraulic brake systems. This appears owing to the fact that, although the braking pressures are equal, the braking forces at the individual wheels differ from one another on account of the different coefficients of friction. Such effects can be effectively compensated for by the direct measurement of the braking force.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a brake system for a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagrammatic illustration of a brake system according to the invention; and
FIG. 2 is an enlarged view, relative to FIG. 1, of a single wheel brake of the novel brake system.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is seen a brake system 1 for a motor vehicle with four wheels (the motor vehicle is not shown in detail for reasons of clarity). The wheels are braked by four brakes 2, which each include a brake disk 3 and an actuating device in the form of a wheel-brake actuator 4. Each wheel-brake actuator 4 is integrated in an associated brake caliper 5, i.e., it is combined with the latter to form a structural unit. The brake caliper 5 is a floating caliper. A braking torque is exerted on the brake disk 3 via brake linings 6 when the wheel-brake actuator 4 is actuated.
Each wheel-brake actuator 4 has an electronic power and control unit 8 which is supplied with control signals, for example for the desired force or pressure to be applied by the wheel-brake actuator 4, from an associated control device 9, and delivers feedback variables, for example relating to the actual value of the force, to the control device 9.
The electronic power and control unit 8 likewise receives from the wheel-brake actuator 4 feedback variables, for example relating to the contact force with which the brake linings 6 are pressed against the brake disk 3 by the brake actuator 4. The desired variables for each wheel-brake actuator are determined by the control device 9 from measured variables which are delivered by various sensors. Such sensors include a force sensor 10 and a displacement sensor 12, which are each integrated with a pedal-force simulator 13 actuated by the brake pedal 14 of the motor vehicle. The pedal-force simulator 13 converts the motion of the brake pedal 14, i.e. the force exerted as usual by the driver and the pedal travel, into electrical signals which are fed to the control device 9. These signals thus represent desired values for the brakes 2, in particular for the vehicle deceleration and the torque or brake torque to be applied to the brake disks. To calculate the desired values in the event of intervention of anti-lock or drive-stability control systems, further sensor signals, for example the transverse acceleration or the yaw angular velocity and the wheel rotary speed, can be evaluated by the control device 9.
The brake system of FIG. 1 has two brake circuits 16 and 17, which are respectively assigned to the front axle and the rear axle. A diagonal assignment of the brake circuits, which is equally possible, differs herefrom only by the wheel-brake units being allocated differently to the control devices and power supplies. Each brake circuit 16, 17 has a separate control device 9 and a separate power supply in the form of a battery Bat.1 or Bat.2 respectively. The energy supplies and the control devices may be accommodated in a common housing in each case, but must then be functionally separate from one another.
In FIG. 1, supply lines are depicted as thick lines and are not provided with arrows; control and signal lines are depicted as thin lines and are provided with arrows in accordance with the signal-flow direction.
The two control devices 9, which work independently of one another, can communicate with one another via a bidirectional signal line and can thereby recognize the failure of a brake circuit 16 or 17 in the respectively other brake circuit. If need be, each brake circuit may take suitable measures. The brake system may also be supplemented by a non-illustrated third control device which, as supervisor, monitors the two brake-circuit control devices.
Referring now more specifically to FIG. 2, a brake disk 21 is braked by two brake pads or brake linings 22 disposed in a brake caliper 23. An electromagnetic brake actuator 24 presses the brake linings 22 against the brake disk 21 during braking. The brake caliper 23 is fastened to a mounting bracket or mount 26 by fastening screws 25.
The brake caliper 23 is only shown schematically here, since such brake calipers are known. The caliper 23 illustrated is a floating caliper and is displaceably mounted in a fixed part. A piston or another actuating element of the wheel-brake actuator 24 presses the left-hand brake lining 22 against the brake disk 21. The reaction force occurring in the process displaces the brake caliper 23 against the frame and the latter pulls the right-hand brake lining 22 against the brake disk 21.
A force sensor 27 is disposed on each of the fastening screws 25. The sensors each measure the force acting on the respective fastening screw and transmit a corresponding signal to the control device 9 (FIG. 1) via signal lines.
In the drawing, the arrangement of the two fastening screws 25 and of the force sensors 27 is shown rotated through 90° into the drawing plane for the sake of clarity. In reality, the two screws and sensors are arranged one behind the other in the circumferential direction of the brake disk, i.e. at right angles to the drawing plane.
A reaction force is produced in the fastening screws 25 due to the adhesion between the roadway and the tire of the motor vehicle, which reaction force corresponds exactly to the braking force at the tire. Due to the lever arm between the force-application point on the brake linings 22 and the fastening screws 25, one of the two fastening screws is stressed in tension and the other in compression. These forces are detected by the two force sensors 27. The two fastening screws 25 are prestressed, and the force sensors 27 measure a force even in the state of rest. The difference between the forces which stress the two fastening screws 25 during braking and which are transmitted from the force sensors 27 to the control unit is a measure of the instantaneous braking force of the tire, and the sum of these two measured forces is a measure of the contact force of the brake actuator 24.
The signals from the force sensors 27 are subtracted or added in the control device and--if necessary by taking into consideration the geometry of the brake using constant factors--directly result in the desired braking forces.
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The brake system of a motor vehicle has a wheel-brake actuator for each wheel brake. The wheel-brake actuator, which is controlled by the brake pedal via electric lines, presses the brake linings against the brake disk. A force sensor senses the circumferential force produced by the brake torque. The output signal of the sensor is taken into account as the current value by the control of the wheel-brake actuator when setting the contact force between the brake linings and the brake disk.
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RELATED APPLICATIONS
[0001] This is a continuation of co-pending application Ser. No. 11/001,698 entitled “Flexible Graphite Article and Method of Manufacture” filed Dec. 1, 2004, which in turn is a continuation of copending and commonly assigned U.S. patent application Ser. No. 09/906,281, filed Jul. 16, 2001, entitled “Flexible Graphite Article and Method of Manufacture,” now U.S. Pat. No. 6,923,631, which in turn is a divisional of U.S. patent application Ser. No. 09/548,118, filed Apr. 12, 2000, entitled “Flexible Graphite Article and Method of Manufacture,” now U.S. Pat. No. 6,432,336, which in turn is a continuation-in-part of U.S. patent application Ser. No. 09/287,899, filed Apr. 7, 1999, the disclosures of each of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to planar flexible graphite articles, such as flexible graphite sheet, and to a system and method for continuously producing such articles. More particularly, the present invention relates to flexible graphite sheet material that exhibits enhanced isotropy with respect to thermal and electrical conductivity and fluid diffusion, as well as to a method for producing the sheet.
BACKGROUND OF THE INVENTION
[0003] Graphites are made up of layer planes of hexagonal arrays or networks of carbon atoms. These layer planes of hexagonally arranged carbon atoms are substantially flat and are oriented or ordered so as to be substantially parallel and equidistant to one another. The substantially flat, parallel equidistant sheets or layers of carbon atoms, usually referred to as basal planes, are linked or bonded together and groups thereof are arranged in crystallites. Highly ordered graphites consist of crystallites of considerable size: the crystallites being highly aligned or oriented with respect to each other and having well ordered carbon layers. In other words, highly ordered graphites have a high degree of preferred crystallite orientation. It should be noted that graphites possess anisotropic structures and thus exhibit or possess many properties that are highly directional, e.g., thermal and electrical conductivity and fluid diffusion. Briefly, graphites may be characterized as laminated structures of carbon, that is, structures consisting of superposed layers or laminae of carbon atoms joined together by weak van der Waals forces. In considering the graphite structure, two axes or directions are usually noted, to wit, the “c” axis or direction and the “a” axes or directions. For simplicity, the “c” axis or direction may be considered as the direction perpendicular to the carbon layers. The “a” axes or directions may be considered as the directions parallel to the carbon layers or the directions perpendicular to the “c” direction. The natural graphites suitable for manufacturing flexible graphite possess a very high degree of orientation.
[0004] As noted above, the bonding forces holding the parallel layers of carbon atoms together are only weak van der Waals forces. Graphites, especially natural graphites, can be treated so that the spacing between the superposed carbon layers or laminae can be appreciably opened up so as to provide a marked expansion in the direction perpendicular to the layers, that is, in the “c” direction and thus form an expanded or intumesced graphite structure in which the laminar character of the carbon layers is substantially retained.
[0005] Natural graphite flake which has been expanded and more particularly expanded so as to have a final thickness or “c” direction dimension which is at least about 80 or more times the original “c” direction dimension can be formed without the use of a binder into cohesive or integrated sheets, e.g., webs, papers, strips, tapes, or the like. The formation of graphite particles which have been expanded to have a final thickness or “c” dimension which is at least 80 times the original “c” direction dimension into integrated sheets by compression, without the use of any binding material is possible. It is believed that this is due to the excellent mechanical interlocking, or cohesion that is achieved between the voluminously expanded graphite particles.
[0006] In addition to flexibility, the sheet material, as noted above, has also been found to possess a high degree of anisotropy with respect to thermal and electrical conductivity and fluid diffusion, comparable to the natural graphite starting material due to orientation of the expanded graphite particles substantially parallel to the opposed faces of the sheet resulting from very high compression, such as roll pressing. Sheet material thus produced has excellent flexibility, good strength and a very high degree of orientation.
[0007] Briefly, the process of producing flexible, binderless anisotropic graphite sheet material comprises compressing or compacting under a predetermined load and preferably in the absence of a binder, expanded graphite particles which have a “c” direction dimension which is at least 80 times that of the original particles so as to form a substantially flat, flexible, integrated graphite sheet. The expanded graphite particles are generally worm-like or vermiform in appearance, and once compressed, will maintain the compression set and alignment with the opposed major surfaces of the sheet. The density and thickness of the sheet material can be varied by controlling the degree of compression. The density of the sheet material can be within the range of from about 5 pounds per cubic foot to about 125 pounds per cubic foot. The flexible graphite sheet material exhibits an appreciable degree of anisotropy due to the alignment of graphite particles parallel to the major opposed, parallel surfaces of the sheet, with the degree of anisotropy increasing upon roll pressing of the sheet material to increased density. In roll pressed anisotropic sheet material, the thickness, i.e. the direction perpendicular to the opposed, parallel sheet surfaces comprises the “c” direction and the directions ranging along the length and width, i.e., along or parallel to the opposed, major surfaces comprises the “a” directions and the thermal, electrical and fluid diffusion properties of the sheet are very different, by orders of magnitude, for the “c” and “a” directions.
[0008] This very considerable difference in properties, i.e., anisotropy, which is directionally dependent, can be disadvantageous in some applications. For example, in gasket applications where flexible graphite sheet is used as the gasket material and in use is held tightly between metal surfaces, the diffusion of fluid like gases or liquids occurs more readily parallel to and between the major surfaces of the flexible graphite sheet. It would, in most instances, provide for greater gasket performance, if the resistance to fluid flow parallel to the major surfaces of the graphite sheet (“a” direction) were increased, even at the expense of reduced resistance to fluid diffusion flow transverse to the major faces of the graphite sheet (“c” direction). With respect to electrical properties, the resistivity of anisotropic flexible graphite sheet is high in the direction transverse to the major surfaces (“c” direction) of the flexible graphite sheet, and very substantially less in the direction parallel to and between the major faces of the flexible graphite sheet (“a” direction). In applications such as seals or other components (such as fluid flow field plates or gas diffusion layers) of fuel cells, it would be of advantage if the electrical resistance transverse to the major surfaces of the flexible graphite sheet (“c” direction) were decreased, even at the expense of an increase in electrical resistivity in the direction parallel to the major faces of the flexible graphite sheet (“a” direction).
[0009] With respect to thermal properties, the thermal conductivity of a flexible graphite sheet in a direction parallel to the upper and lower surfaces of the flexible graphite sheet is relatively high, while it is relatively very low in the “c” direction transverse to the upper and lower surfaces. At times, and in certain applications, such as thermal interfaces, it may be desirable to increase the thermal conductivity of the sheet in the “c” direction.
[0010] In some applications, it is important to incorporate additives in the flexible graphite sheet in order to achieve corrosion resistance and to impregnate the flexible graphite sheet with resins and/or other material to increase the strength and water resistance of the flexible graphite sheet. Also, it is important at times to provide such additives in the course of processing the natural graphite into flexible graphite.
[0011] These foregoing situations are accommodated by the present invention.
SUMMARY OF THE INVENTION
[0012] In accordance with the present invention, a flexible graphite article in the form of a sheet having opposed, relatively planar, major surfaces is provided. The article is formed of particles of expanded (or exfoliated) graphite, an optically detectable portion of which, at magnifications of 100× or less, are substantially unaligned with the opposed planar major surfaces of the flexible graphite article. Preferably, at least a portion of the unaligned particles are transverse to the opposed major surfaces of the article. The flexible graphite article is characterized by having decreased electrical resistivity and increased thermal conductivity in a direction transverse to the opposed planar major surfaces of the flexible graphite sheet and increased resistance to fluid flow in a direction parallel to the opposed planar major faces of the flexible graphite sheet. The flexible graphite sheet, with or without additives and/or impregnants, can be mechanically altered, such as by embossing, die molding and cutting to form components for electrochemical fuel cells, gaskets and heat conducting and heat resistant articles.
[0013] The present invention also includes an apparatus, system and method for producing flexible graphite sheet articles, such as those having decreased electrical resistivity and increased thermal conductivity in a direction transverse to the opposed planar major surfaces of the flexible graphite sheet and increased resistance to fluid flow in a direction parallel to the opposed planar major faces of the flexible graphite sheet.
[0014] The inventive method comprises reacting raw graphite particles with a liquid intercalant solution to form intercalated graphite particles; exposing the intercalated graphite particles to a temperature of at least about 700° C. to expand the intercalated graphite particles to form a stream of exfoliated graphite particles; continuously compressing the stream of exfoliated graphite particles into a continuous coherent self-supporting mat of flexible graphite; continuously contacting the flexible graphite mat with liquid resin and impregnating the mat with liquid resin; and continuously calendering the flexible graphite mat to increase the density thereof to form a continuous flexible graphite sheet having a density of from about 5 to about 125 lbs/ft 3 and a thickness of from about 1.0 to 0.003 inches.
[0015] The method also advantageously includes mechanically deforming a surface of the continuous flexible graphite sheet to provide a series of repeating patterns on a surface of the flexible graphite sheet or the removal of material from the flexible graphite sheet in a series of repeating patterns and vaporizing at least some of the solvent from the resin prior to mechanically deforming a surface of the continuous flexible graphite sheet.
[0016] As noted, the present invention also includes an apparatus for the continuous production of resin-impregnated flexible graphite sheet, comprising a reactor vessel for containing as reactants graphite particles in mixture with a liquid intercalant solution to form intercalated graphite particles; an expansion chamber in operative connection with the reactor vessel, the interior of the expansion chamber being at a temperature of at least about 700° C. (and preferably enclosing an open flame), such that passing intercalated graphite particles from the reactor vessel to the expansion chamber causes expansion of the intercalated graphite particles to form exfoliated graphite particles; a compression station positioned to receive exfoliated graphite particles for compressing such particles into a coherent self-supporting mat of flexible graphite; an impregnation chamber for contacting the flexible graphite mat with liquid resin and impregnating the mat with the liquid resin; a calendar mill disposed to receive the flexible graphite mat for increasing the density of the mat to form a continuous flexible graphite sheet preferably having a density of from about 5 to about 125 lbs/ft 3 and a thickness of no more than about 1.0 inches, more preferably about 1.0 to about 0.003 inches.
[0017] The inventive apparatus also preferably includes a device for mechanically deforming a surface of the continuous flexible graphite sheet to provide a series of repeating patterns on a surface of the flexible graphite sheet or the removal of material from the flexible graphite sheet in a series of repeating patterns. It further advantageously has an oven for receiving the mat from the device for mechanically deforming a surface of the continuous flexible graphite sheet, to cure the resin with which the continuous flexible graphite sheet is impregnated.
[0018] In a particular embodiment of the invention, a system for the continuous production of surface patterned, resin-impregnated flexible graphite sheet is presented. The system includes:
[0019] (i) a reactor vessel for containing as reactants raw natural graphite flake-like particles in mixture with sulfuric and nitric acids;
[0020] (ii) an acid containing vessel communicating with said reactor vessel for the introduction of a mixture of sulfuric and nitric acid into said reactor vessel;
[0021] (iii) a graphite particle containing vessel for the introduction of graphite particles into the reactor vessel;
[0022] (iv) a first additive containing vessel communicating with said reactor vessel for the introduction of intercalation enhancing materials, acids or organic chemicals;
[0023] (v) a wash vessel containing water communicating with the reactor vessel to receive reaction product in the form of acid intercalated graphite particles and remove acid from the surface of the acid intercalated graphite particles and a portion of the mineral impurities contained in the natural graphite particles introduced into the reactor vessel;
[0024] (vi) a drying chamber for drying washed acid intercalated graphite particles;
[0025] (vii) conduit means extending from said wash vessel to said drying chamber for passing washed acid intercalated graphite particles from the wash vessel to the drying chamber;
[0026] (viii) a second additive containing vessel communicating with the conduit means of (vii) for adding pollution reducing chemicals to the washed, intercalated graphite particles to the washed acid intercalated graphite particles;
[0027] (ix) a collecting vessel for collecting washed acid intercalated graphite particles admixed with pollution reducing chemicals;
[0028] (x) conduit means extending from said drying chamber to said collecting vessel for passing acid intercalated graphite particles admixed with acid additives from said drying chamber to said collecting vessel;
[0029] (xi) a third additive containing vessel communicating with said conduit of (x) for the introduction of ceramic fiber particles in the form of macerated quartz glass fibers, carbon and graphite fibers, zirconia, boron nitride, silicon carbide and magnesia fibers, naturally occurring mineral fibers such as calcium metasilicate fibers, calcium aluminum silicate fibers, aluminum oxide fibers and the like into said conduit and the admixing and entrainment thereof with acid intercalated graphite particles passing from the washing vessel to the drying chamber;
[0030] (xii) an expansion chamber enclosing an open flame at a temperature of 800 to 1300° C.;
[0031] (xiii) conduit means extending from said collecting vessel to said expansion chamber for passing dried acid intercalated graphite particles admixed with ceramic particles to said expansion chamber;
[0032] (xiv) gas inlet means communicating with the conduit means of (xii) for entraining the acid intercalated graphite particles admixed with ceramic particles in a stream of non-reactive gas and passing the entrained acid intercalated graphite particles admixed with ceramic particles into the open flame enclosed in said expansion chamber to cause expansion of the acid intercalated graphite particles of at least about 80 times to form vermiform elongated graphite particles;
[0033] (xv) a collecting hopper for receiving said vermiform elongated graphite particles admixed with ceramic particles;
[0034] (xvi) a separator vessel interposed between the expansion chamber and the collecting hopper to collect by gravity separation heavy solid mineral impurity particles from the mixture of vermiform graphite particles with ceramic particles;
[0035] (xvii) a gas scrubber communicating with said collecting hopper to collect gases generated in the expansion chamber;
[0036] (xviii) a compression chamber positioned to receive vermiform graphite particles mixed with ceramic fiber particles for compressing said vermiform particles mixed with ceramic particles into a coherent self-supporting mat of flexible graphite from about 1 to about 0.015 inches in thickness and having a density of from about 5 to about 25 lbs./ft. 3 ;
[0037] (xix) an impregnation chamber for contacting the flexible graphite mat of (xviii) with liquid resin and impregnating said flexible graphite with liquid resin;
[0038] (xx) a dryer disposed to receive the impregnated flexible graphite mat of (xix) and heat and dry said mat;
[0039] (xxi) a calendar mill disposed to receive the flexible graphite mat of (xix) for increasing the density of said flexible graphite mat to form a continuous flexible graphite sheet having a density of from about 5 to about 80 lbs/ft 3 , a thickness of from about 0.5 to about 0.005 inches and relatively evenly spaced apart opposite surfaces;
[0040] (xxii) a device for mechanically deforming a surface of the continuous flexible graphite sheet of (xxi) to provide a series of repeating patterns on said surface flexible graphite sheet or the removal of material from said flexible graphite sheet in a series of repeating patterns; and
[0041] (xxiii) an oven for receiving the mat from the dryer of (xxii) to cure the resin the mat.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIGS. 1 , 1 (A) show the making of a mass of un-aligned expanded graphite particles;
[0043] FIGS. 2 , 2 (A) show planar bodies of flexible graphite having portions of un-aligned graphite particles;
[0044] FIG. 3 shows a planar body of flexible graphite that does not have portions of un-aligned graphite particles;
[0045] FIG. 4 is a photograph (original magnification 100×) of a planar body of flexible graphite that corresponds to the sketch of FIG. 2 ;
[0046] FIG. 5 shows a system for the continuous production of mechanically deformed planar flexible graphite articles;
[0047] FIGS. 5(A) and 5(B) show different types of the flexible graphite articles noted above; and
[0048] FIGS. 5(C) and 5(D) show conventional mechanisms for producing different types of flexible graphite articles noted above.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0049] Graphite is a crystalline form of carbon comprising atoms covalently bonded in flat layered planes with weaker bonds between the planes. By treating particles of graphite, such as natural graphite flake, with an intercalant of, e.g., a solution of sulfuric and nitric acid, the crystal structure of the graphite reacts to form a compound of graphite and the intercalant. The treated particles of graphite are often referred to as “particles of intercalated graphite.” Upon exposure to high temperature, the particles of intercalated graphite expand in dimension as much as about 80 or more times its original volume in an accordion-like fashion in the “c” direction, i.e., in the direction perpendicular to the crystalline planes of the graphite. The exfoliated graphite particles are vermiform in appearance, and are therefore commonly referred to as worms. The worms may be compressed together into flexible sheets that, unlike the original graphite flakes, can be formed and cut into various shapes.
[0050] A common method for manufacturing graphite sheet or foil is described by Shane et al. in U.S. Pat. No. 3,404,061, the disclosure of which is incorporated herein by reference. In the typical practice of the Shane et al. method, natural graphite flakes are intercalated by dispersing the flakes in a solution containing an oxidizing agent of, for instance, a mixture of nitric and sulfuric acid. The intercalation solution contains oxidizing and other intercalating agents known in the art. Examples include those containing oxidizing agents and oxidizing mixtures, such as solutions containing nitric acid, potassium chlorate, chromic acid, potassium permanganate, potassium chromate, potassium dichromate, perchloric acid, and the like, or mixtures, such as for example, concentrated nitric acid and chlorate, chromic acid and phosphoric acid, sulfuric acid and nitric acid, or mixtures of a strong organic acid, e.g. trifluoroacetic acid, and a strong oxidizing agent soluble in the organic acid.
[0051] In a preferred embodiment, the intercalating agent is a solution of a mixture of sulfuric acid, or sulfuric acid and phosphoric acid, and an oxidizing agent like nitric acid, perchloric acid, chromic acid, potassium permanganate, hydrogen peroxide, iodic or periodic acids, or the like. Although less preferred, the intercalation solutions may contain metal halides such as ferric chloride, and ferric chloride mixed with sulfuric acid, or a halide, such as bromine as a solution of bromine and sulfuric acid or bromine in an organic solvent.
[0052] After the flakes are intercalated, any excess solution is drained from the flakes and the flakes are water-washed. The quantity of intercalation solution retained on the flakes after draining may range from 20 to 150 parts of solution by weight per 100 parts by weight of graphite flakes (pph) and more typically about 50 to 120 pph. Alternatively, the quantity of the intercalation solution may be limited to between 10 to 50 parts of solution per hundred parts of graphite by weight (pph) which permits the washing step to be eliminated as taught and described in U.S. Pat. No. 4,895,713, the disclosure of which is also herein incorporated by reference.
[0053] Referring now to FIG. 1 , intercalated graphite flakes are advantageously exfoliated into flexible graphite particles by passing a stream of intercalated graphite flakes 2 through a flame 3 for only a few seconds at temperature up to or greater than 700° C., more typically 1000° C. or higher, to exfoliate, i.e. expand the particles, and a resulting stream of expanded graphite particles, or worms 5 , are passed to the top 6 of a large open-topped vessel 7 into which the particles fall freely and are randomly dispersed. From about 1-30% by weight of ceramic additives, indicated at 4 , can be blended with the intercalated graphite flakes 2 to provide enhanced properties in the final flexible graphite product. The additives include ceramic fiber particles having a length of 0.15 to 1.5 millimeters. The width of the particles is suitably from 0.04 to 0.004 mm. The ceramic fiber particles are non-reactive and non-adhering to graphite and are stable at temperatures up to 2000° F., preferably 2500° F. Suitable ceramic fiber particles are formed of macerated quartz glass fibers, carbon and graphite fibers, zirconia, boron nitride, silicon carbide and magnesia fibers, naturally occurring mineral fibers such as calcium metasilicate fibers, calcium aluminum silicate fibers, aluminum oxide fibers and the like.
[0054] The dispersed expanded particles 5 , with optional additive 4 , are collected and confined in the large open-topped vessel as a layer 8 of pre-determined depth “d” and are to a large extent omnidirectionally oriented, with some horizontally aligned, as shown at 50 in FIG. 1(A) , and many extending in other directions, including vertically as shown at 500 in FIG. 1(A) , and in various directions other than vertical or horizontal as shown as 5000 in FIG. 1(A) . The large open-topped vessel used to collect the omnidirectionally oriented particles can be in the form of a mold as shown at 7 shaped to receive a die 9 which is used to compress the layer 8 of omnidirectionally oriented exfoliated graphite particles 50 , 500 , 5000 to a density of from about 0.1 to 25 pounds per cubic foot at a thickness of from 25 to 0.15 inches. Under these conditions, the omnidirectional orientation of the exfoliated acid treated graphite is conserved to a substantial extent in the compressed planar flexible graphite article 100 , having parallel opposed faces or major surfaces 101 , 103 , as shown in the sketch of the edge of the planar article illustrated in FIG. 2 and is also conserved when the material of FIG. 2 is pressed into sheet having a density of 25 to 100 pounds per cubic foot and a thickness of 0.15 to 0.04 inch as shown in the similar sketch of FIG. 2(A) .
[0055] The use of continuous converging opposing belts, as shown at 457 , 458 in FIG. 5 , such as porous belts converging from a spacing of 25 inches to a spacing of 0.15 inch over a length of 8 to 12 feet, approximates the action of a mold and die with longer lengths, more than 8 feet providing increased conservation of omnidirectional orientation. A prior art highly densified sheet 200 of directly roll pressed intercalated acid treated graphite is illustrated in the sketch of FIG. 3 which shows the orientation of the exfoliated, expanded graphite particles 210 to be substantially parallel to the major opposed parallel surfaces 301 , 303 of the planar sheet 200 . FIG. 4 is a photograph of the edge of a compressed (100 lb./cu. ft.) planar article in accordance with the present invention corresponding generally to the sketch of FIG. 2 with the omnidirectionally oriented exfoliated, expanded graphite particles being correspondingly indicated at 50, 500, 5000.
[0056] The article of FIG. 3 is highly anisotropic with respect to thermal and electrical conductivity; the articles of FIGS. 2 , 2 (A) and 4 exhibit enhanced isotropy with respect to thermal and electrical conductivity, as compared to the article of FIG. 3 .
[0057] The articles of FIGS. 2 , 2 (A) and the material shown in the photograph (100×) of FIG. 4 can be shown to have increased thermal and electrical conductivity in the direction transverse to opposed planar surfaces 101 , 103 as compared to the thermal and electrical conductivity in the direction transverse to surfaces 301 , 303 of prior art material of FIG. 3 in which particles of expanded natural graphite unaligned with the opposed planar surfaces are not optically detectable.
[0058] With reference to FIG. 5 , a system is disclosed for the continuous production of roll-pressed flexible graphite sheet. In the inventive system, graphite flakes and a liquid intercalating agent are charged into reactor 404 . More particularly, a vessel 401 is provided for containing a liquid intercalating agent. Vessel 401 , suitably made of stainless steel, can be continually replenished with liquid intercalant by way of conduit 406 . Vessel 402 contains graphite flakes that, together with intercalating agents from vessel 401 , are introduced into reactor 404 . The respective rates of input into reactor 404 of intercalating agent and graphite flake are controlled, such as by valves 408 , 407 . Graphite flake in vessel 402 can be continually replenished by way of conduit 409 . Additives, such as intercalation enhancers, e.g., trace acids, and organic chemicals may be added by way of dispenser 410 that is metered at its output by valve 411 .
[0059] The graphite flakes in reactor vessel 404 are subjected to interlayer attack by the acid mixture intercalant, as described in U.S. Pat. No. 3,404,061 to Shane et al. The resulting intercalated graphite particles are soggy and acid coated and are conducted (such as via conduit 412 ) to a wash tank 414 where the particles are washed, advantageously with water which enters and exits wash tank 414 at 416 , 418 . The washed intercalated graphite flakes are then passed to drying chamber 422 such as through conduit 420 . Additives such as buffers, antioxidants, pollution reducing chemicals can be added from vessel 419 to the flow of intercalated graphite flake for the purpose of modifying the surface chemistry of the exfoliate during expansion and use and modifying the gaseous emissions which cause the expansion.
[0060] The intercalated graphite flake is dried in dryer 422 , preferably at temperatures of about 75 to about 150° C., generally avoiding any intumescence or expansion of the intercalated graphite flakes. After drying, the intercalated graphite flakes are fed as a stream into flame 300 , by, for instance, being continually fed to collecting vessel 424 by way of conduit 426 and then fed as a stream into flame 300 in expansion vessel 428 as indicated at 2 . Additives such as ceramic fiber particles formed of macerated quartz glass fibers, carbon and graphite fibers, zirconia, boron nitride, silicon carbide and magnesia fibers, naturally occurring mineral fibers such as calcium metasilicate fibers, calcium aluminum silicate fibers, aluminum oxide fibers and the like can be added from vessel 429 to the stream of intercalated graphite particles propelled by entrainment in a non-reactive gas introduced at 427 .
[0061] The intercalated graphite particles 2 , upon passage through flame 300 in expansion chamber 301 , expand more than 80 times in the “c” direction and assume a “worm-like” expanded form; the additives introduced from 429 and blended with the stream of intercalated graphite particles are essentially unaffected by passage through the flame 300 . The expanded graphite particles may pass through a gravity separator 430 , in which heavy ash natural mineral particles are separated from the expanded graphite particles, and then into a wide topped hopper 432 . Separator 430 can be by-passed when not needed.
[0062] The expanded, i.e., exfoliated graphite particles fall freely in hopper 432 together with any additives, and are randomly dispersed and passed into compression station 436 , such as through trough 434 . Compression station 436 comprises opposed, converging, moving porous belts 457 , 458 spaced apart to receive the exfoliated, expanded graphite particles 50 , 500 , 5000 . Due to the decreasing space between opposed moving belts 457 , 458 , the exfoliated expanded graphite particles are compressed into a mat of flexible graphite, indicated at 448 having thickness of, e.g., from about 1.0 to 0.003, especially from about 1.0 to 0.1 inches, and a density of from about 5 to 125 lbs./ft 3 . Gas scrubber 449 may be used to remove and clean gases emanating from the expansion chamber 301 and hopper 432 .
[0063] The mat 448 is passed through vessel 450 and is impregnated with liquid resin from spray nozzles 438 , the resin advantageously being “pulled through the mat” by means of vacuum chamber 439 and the resin is thereafter preferably dried in dryer 460 reducing the tack of the resin and the resin impregnated mat 443 is thereafter densified into roll pressed flexible graphite sheet 447 in calendar mill 470 . Gases and fumes from vessel 450 and dryer 460 are preferably collected and cleaned in scrubber 465 .
[0064] The calendered flexible graphite sheet 447 is passed through surface shaping unit 480 and is mechanically deformed at its surface by embossing die stamping or the like, and thereafter heated in oven 490 to cure the resin, to continuously provide a flexible graphite sheet 444 of repeated surface altered patterns such as the grooved patterns 600 shown in FIG. 5A , which can be cut to provide flexible graphite components 650 of a fuel cell such as fluid flow plate shown at 650 in FIG. 6A or gaskets 750 as shown at 700 in FIG. 5B .
[0065] Depending on the nature of the resin system employed, and especially the solvent type and level employed, a vaporization drying step may be included prior to the surface shaping (such as embossing) step. In this drying step, the resin impregnated flexible graphite sheet is exposed to heat to vaporize and thereby remove some or all of the solvent, without effecting cure of the resin system. In this way, blistering during the curing step, which can be caused by vaporization of solvent trapped within the sheet by the densification of the sheet during surface shaping, is avoided. The degree and time of heating will vary with the nature and amount of solvent, and is preferably at a temperature of at least about 90° C. and more preferably from about 90° C. to about 125° C. for about 3 to about 20 minutes for this purpose.
[0066] The above description is intended to enable the person skilled in the art to practice the invention. It is not intended to detail all of the possible variations and modifications which will become apparent to the skilled worker upon reading the description. It is intended, however, that all such modifications and variations be included within the scope of the invention which is defined by the following claims. The claims are intended to cover the indicated elements and steps in any arrangement or sequence which is effective to meet the objectives intended for the invention, unless the context specifically indicates the contrary.
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A flexible graphite sheet exhibiting enhanced isotropy is provided. In addition, an apparatus, system and method for continuously producing a resin-impregnated flexible graphite sheet is also provided.
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FIELD OF THE INVENTION
This invention claims the benefit of US Provisional Application No. 61/355,857 titled “Air Cycle Heat Pump Clothes Dryer” filed on Jun. 17, 2010, which is hereby incorporated by reference (see additional incorporations by reference in paragraph below). Applicant claims priority pursuant to 35 U.S.C. Par 119( e )(i). The present invention relates to dryers, more particularly to clothes dryers which utilize a heat pump.
US Patent Application 2007/0256430 filed by Prueitt is hereby incorporated by reference. U.S. Pat. No. 7,726,960 by Kim Tiow Oui is also incorporated by reference.
BACKGROUND
In a traditional dryer shown in FIG. 1 , clothes are placed in a rotating tumbler. Air from the outside is drawn in, heated, circulated through the tumbler and vented outside.
Even though the basic design is simple, reliable, and cheap, the high operating temperature (about 180 F) causes lint to form and clothes to shrink. In addition, this basic design requires venting ducts to the outside to prevent the buildup of high indoor humidity. It is inherently inefficient because no attempt is made to recycle the heat that is applied to the laundry load.
Just as in a traditional dryer, a condenser dryer illustrated in FIG. 2 requires that heated air pass through the load. However, instead of venting this air outside, the dryer uses a heat exchanger to cool the air and condense the water vapor. After the water is extracted, the air is heated and goes through the loop again. The heat exchanger uses as its coolant, ambient air which is vented in the immediate surroundings; alternatively it may use cold water, resulting in increased water usage.
Even though condenser dryers are “closed loop” requiring no venting of the humid air from the laundry, they do not recycle heat energy and their heat exchangers still dump heat in the environment. They are about 15% less efficient than conventional clothes dryers because of inefficiency introduced by the heat exchanger.
In a heat pump dryer shown in FIG. 3 heat energy is recycled. The same heat pump is used simultaneously to cool the air leaving the tumbler and to heat the air entering the tumbler. Such dryers not only avoid the need for ducting, but also conserve much of their heat within the dryer instead of exhausting it into the surroundings. Heat pump dryers can therefore use less than half the energy required by either condensation or traditional dryers.
Disadvantages of heat pump dryers include their need for two heat exchangers and their reliance on hydrochlorofluorocarbon (HCFCs) refrigerant fluids such as R-22 or R-134a. These fluids have been shown to be 2000 times more powerful than carbon dioxide at causing global warming. Their predecessors, the Chlorofluorocarbons (CFCs) such as Freon™, were banned because of their deleterious effect on the ozone layer. There is therefore a strong incentive to eliminate these chemicals from devices using a heat pump such as clothes dryers and, air conditioners. The proposed technology is an improvement to, and is more efficient, simple, compact and environmentally friendly than, the heat pump dryer.
Vacuum dryers are the subject of numerous patents. However, very little of this technology has reached the market because of their slow drying speed. Little consideration is given in the prior art to how the heat flows: as water evaporates, heat of vaporization is provided by the clothes which get colder, slowing down the evaporation process. Heating the clothes, a possible solution, is inefficient and does not address the issue of recycling the heat energy. Another problem is their need for a strong sealed vacuum chamber to enclose the tumbler and the possibility of implosion should this chamber fail.
Microwave dryers operate around 2.45 GHz. At this frequency microwaves have the interesting property of being selectively absorbed by water and are appropriate for food items. Unfortunately the presence of metal in clothing could result in sparking and fires, making microwaves unacceptable for laundry applications. No clothes dryer described in the prior art, however, offers the economy, reliability, efficiency and environment sustainability of the present invention. Further features, aspects, and advantages of the present invention over the prior art will be more fully understood when considered with respect to the following detailed description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is prior art and illustrates the construction of a traditional clothes dryer comprising of a tumbler and an air heater module.
FIG. 1A is prior art and shows a condenser clothes dryer comprising a tumbler and a heat exchanger.
FIG. 1B is prior art and shows a dryer utilizing a heat pump comprising a pump and a Venturi valve.
FIG. 2 illustrates a possible implementation of this invention. It comprises a tumbler, a pump and a heat exchanger.
FIG. 3 provides an illustration of an alternative embodiment comprising a turbo-compressor and a turbine.
FIG. 4 presents time graphs of expected changes in temperature and pressure of the air as it goes around the cycle.
FIG. 5 illustrates hybrid approaches which may include a heater to provide heat to the air before it enters the tumbler, a bleed-off valve to create a vacuum in the tumbler enclosure, a supplemental heat exchanger to further cool the air and valves to convert the closed loop into an open loop.
FIG. 5A illustrates how a bleed valve positioned at a high pressure point and an air insert valve located at a low pressure point can be used to operate the device in a partially open loop mode.
FIG. 5B illustrates how a bleed valve assisted by a pump and positioned at a low pressure point and an air insert valve assisted by a pump and located at a high pressure point can be used to operate the device in a partially open loop mode.
FIG. 5C illustrates how a second heat exchanger can be positioned between the primary heat exchanger and the expander.
FIG. 6 shows how the device could be constructed in module by separating for example the heat exchanger from the tumbler module.
SUMMARY OF THE INVENTION
The proposed dryer technology is an improvement to the conventional heat pump dryer. It is more efficient, simpler and environmentally safer. The refrigerant cycle, based on a hydrochlorofluorocarbon-based fluid in a conventional heat pump dryer, is replaced in the proposed system by an air cycle, thereby eliminating one heat exchanger and shortening the path of the heat flow. Instead of having to traverse four boundary layers and two heat exchanger walls (air/wall/fluid, fluid/wall/air), heat needs to cross only two boundary layers and one wall (air/wall/air) resulting in heightened efficiency, simplicity and compactness. In addition, the need for a hydrochlorofluorocarbon refrigerant fluid having a global heat warming capacity 2000 times greater than carbon dioxide is eliminated. The proposed dryer can be closed loop, requiring no venting or exhaust. Because both heat and mechanical energy can be regenerated, it produces little heat compared to other dryers. Assuming ideal conditions such as no friction and no turbulence, it can operate in a thermodynamically reversible fashion and approach the maximum thermodynamically allowed efficiency.
In one embodiment of the proposed invention, air goes through the following:
1. The air from the tumbler and laden with moisture is directed through a pump also named compressor which adiabatically compresses and heats it. The terms compressor and pump shall be used interchangeably. 2. The hot compressed and humid air then traverses the hot side of a heat exchanger where it loses its heat energy. 3. The air is then allowed to expand adiabatically through a Venturi valve where it loses more energy, cooling to a temperature significantly below its dew point. 4. The cold air filled with condensed water is then directed through a separator (for example a cyclone) that extracts the liquid water condensate. 5. The air is then fed back into the cold side 6 of the heat exchanger, where it recaptures some of the heat that it has previously lost; 6. The warm air is then blown through the wet laundry in the tumbler 1 where it acquires some moisture. 7. Finally the air is directed back to the pump, thus closing the loop.
An alternative design utilizes a turbo compressor and turbine in lieu of a pump and a Venturi valve, thereby recycling mechanical energy in addition to the heat energy already recycled by the heat exchanger.
The invention also includes a method of drying wet objects, comprising:
a. passing air through the wet objects. This step allows the air to absorb moisture from the wet objects; b. compressing the air. Adiabatic compression results in heating of the air; c. extracting heat from the air by passing it through the hot side of a heat exchanger. This step cools the air; d. expanding the air. This step cools the air even further, below its dew point; e. separating condensate from the air; f. restoring all or part of the heat that has been extracted to the air by passing it through the heat exchanger's cold side. This step heats the air. g. redirecting all or part of the air back to the wet objects thereby forming a loop in the flow of the air.
Other alternatives also comprise a heater that heats the air before it enters the tumbler enclosure; a bleed valve located after the compressor, for creating a partial vacuum within the tumbler enclosure to speed up the evaporation of water; a secondary heat exchanger located after the Venturi valve or after the turbine for removing additional heat from the air, wherein this secondary heat exchanger can have its cold side connected to a source of cool fluid such as tap water; and a valve system to bleed air off the loop or inserting air in the loop depending on whether outside air has better drying capacity than the air in the loop.
DETAILED DESCRIPTION
An embodiment of the invention is illustrated in FIG. 2 . Clothes are placed in an enclosed tumbler 1 . The air which is blown through it goes through the following:
1. The air from the tumbler and laden with moisture is directed through a pump 2 which adiabatically compresses and heats it. 2. The hot compressed and humid air then traverses the first side 3 of a heat exchanger where it loses its heat energy. 3. The air is then allowed to expand adiabatically through a Venturi valve 4 where it loses more energy, cooling to a temperature significantly below its dew point. 4. The cold air filled with condensed water is then directed through a separator 5 (for example a cyclone) that extracts the liquid water condensate. 5. The air is then fed back into the second side 6 of the heat exchanger, where it recaptures some of the heat that it has previously lost; 6. The warm air is then blown through the wet laundry in the tumbler 1 where it acquires some moisture. 7. Finally the air is directed back to the pump 2 , thus closing the loop.
This dryer implementation has noteworthy differences with a conventional heat pump dryer:
1. Air is used as a refrigerant fluid instead of a global warming Hydrochlorofluorocarbon (HCFC) fluid, making this dryer more eco-friendly. These compounds have been found to be 2000 times more powerful than carbon dioxide as global warming gases. 2. This dryer is simpler and more compact because it has one heat exchanger 12 instead of two. 3. It is more efficient than a conventional heat pump dryer because heat needs to cross only two boundary layers and a single heat exchanger wall (air/wall/air) instead of four boundary layers and two heat exchanger walls (air/wall/fluid, fluid/wall/air). Greater efficiency results in less heat dumped into the environment.
An alternative version of this invention is presented in FIG. 3 , which makes use of the well known inverted Brayton cycle. This version is similar to the first, except that the pump is replaced by a turbo compressor 7 and the Venturi valve 4 by a turbine 8 . This approach allows the mechanical energy generated by the air as it expands through the turbine 8 to be recycled back to the compressor 7 through a common axle between the compressor 7 and the turbine 8 . One should note that this version is thermodynamically reversible assuming no friction, no turbulence and a perfect heat exchanger, and, therefore, in theory, it has the highest possible efficiency and the lowest heat generation. Heat is recycled by the heat exchanger 12 and mechanical energy is recycled by the compressor 7 and turbine 8 . The heat of vaporization of water is recovered since the condensate 11 is liquid. In the limit when there is no temperature difference between the laundry and the condensate 11 , the required energy is zero. Of course, this is an ideal case: system inefficiencies do exist and the process must be driven forward and, therefore, energy must be expended. However, this argument points to the potential for high efficiency and low thermal emission by the proposed dryer.
The compressor 7 and turbine 8 combination operating a Brayton cycle is a mature technology. A study [1] has been conducted by Gui, Reinarts and Scaringe for the US Air Force to develop high speed, low flow rate centrifugal compressors for air-conditioning application in aircraft. The same type of compressor can be used for the proposed dryer. Conventional ball bearings can be used. Advances in bearing technology, more particularly in magnetic bearings, make this compressor/turbine combination very efficient and reliable. Turbo compressor and turbine technology is well known and will not add significant risk to this approach.
In this alternate embodiment, the performance of the dryer depends on the performance of the compressor 7 and turbine 8 which in turn depends on the type of bearings they employ. A lot of information can be found in the literature regarding such bearings, in particular bearings used for centrifuge and ultra centrifuge and bearings used in turbochargers. Of particular interest are conventional ball bearings, active magnetic bearings (which are relatively expensive), passive magnetic bearings and air foil bearings. If magnetic bearings are used it may be advantageous to combine the bearing mechanism with the electric drive mechanism. Mohawk Innovative Technology Inc. is one of the manufacturers of air foil bearings and hybrid foil magnetic bearings.
As is well know to persons versed in the art, the turbo-compressor and turbine combination is one of several possible methods of compressing and decompressing air, which include reciprocating pumps and rotary devices. For example one could use a rotary compressor such as the kind described in U.S. Pat. No. 7,726,960 by Kim Tiow Oui, which is incorporated by reference.
FIG. 4 shows n example of how temperature and pressure are changing around the air cycle loop.
Hybrid approaches are also possible. For example, the embodiments discussed above do not utilize a heater (as traditional dryers do) and a vacuum (as vacuum dryers). However, these features are not incompatible with this invention and can easily be incorporated in the following four embodiments of the invention illustrated in FIG. 5 .
A filter 15 can be added after the tumbler to remove material such as lint if the objects being dried are clothes.
The drying speed can be speeded up by passing the air through a heater 9 before it enters the tumbler 1 .
The drying speed can also be speeded up by creating a partial vacuum in the tumbler 1 . This can be done in the first embodiment (pump and Venturi valve) by bleeding off air after the pump 2 stage by means of a bleed valve 10 , or, as shown in FIG. 5 for the second embodiment (turbo compressor 7 and turbine 8 ), by adjusting the operation of the compressor 7 and turbine 8 . The trade-off, of course, is that the container holding the tumbler must be sturdily built and its door must include a vacuum seal. In addition the lower heat capacity of the air at low pressure slows down the drying process.
The technique used in condenser clothes dryers can be borrowed by adding a secondary heat exchanger 13 that uses water to cool the circulating air. The trade-off in this case is that heat is dumped in the environment.
The dryer could be operated in a fully closed loop or in a partially open loop. The air at any point around the loop may have a lower drying capacity than outside air, this drying capacity being a function of its relative humidity and temperature. If the drying capacity of the air at any point in the loop is higher than that of the outside air, then it is preferable to operate in a closed loop fashion. Otherwise, it is more efficient to open the loop and replace some or all of the air at that point in the loop by air from outside (unless there is no convenient venting or exhaust for the dryer, as in a submarine or to save space, in a building). Open loop operation shown in FIG. 5A is implemented by the insertion of valves 16 and 17 designed to switch the configuration of the loop from closed to open. For example, the bleed off valve 16 can be located where pressure is high, that is, immediately after the compressor, and the air insertion valve 17 can be located where pressure is low, that is, immediately before the compressor. Such valves can also be located at other points around the loop but the air would have to be actively bled or inserted by separate pumps. For example as shown in FIG. 5B a bleed off valve 16 could be located immediately before the compressor to get rid of air laden with moisture, but, because of the low pressure, a separate pump 18 would have to be installed to force air outside. Similarly an air insertion valve 17 could be installed immediately after the separator but, because of the high pressure, a separate pump 19 would have to be installed to force air inside the loop.
FIG. 5C illustrates how a second heat exchanger 13 can be positioned between the primary heat exchanger 12 and the expander 4 . This secondary heat exchanger 13 would utilize an available source of cold fluid such as outside air or tap water 20 .
The dryer can be built in modular fashion. For example as shown in FIG. 6 , the heat exchanger module 12 can be built in a separate compartment from the tumbler 1 and the enclosure 14 of the tumbler can be made of hinged plates for easy storage, transportation and assembly.
This invention has the following advantages:
1. Completely Green: Air itself is used as a refrigerant and therefore no global warming refrigerant fluid is required. Conventional refrigerant fluids, (hydrochlorofluorocarbons or HCFCs), have a global warming potential 2000 times that of carbon dioxide and are employed by conventional heat pump dryers. 2. Closed Loop: Air is recirculated; no venting or exhaust is required except that condensate water must be drained. 3. Efficient: The proposed technology has better performance than a conventional heat pump dryer because of the greater efficiency of the heat exchangers. In the proposed dryer, heat needs to traverse only two boundary layers and a single heat exchanger wall (air/wall/air). In conventional heat pump dryers, heat must cross four boundary layers and two heat exchanger walls (air/wall/fluid, fluid/wall/air). 4. Energy Regenerating: In both proposed versions, heat is recirculated through the heat exchanger 12 . Furthermore, in Version 2, mechanical energy is recycled from the turbine 8 to the compressor 2 . This approach minimizes the heat transferred to the indoor environment. 5. Simple, Compact and Economical Design: The proposed dryer is simpler, more compact and more economical than a conventional heat pump because it requires only one heat exchanger instead of two. 6. Low Heat Emission: Because of the high efficiency of the proposed design, very little heat is dumped into the environment. Unlike in a traditional dryer, the proposed dryer does not rely on heating of the air beyond the adiabatic heating by the compressor. Hybrid options, shown in FIG. 5 , include a heater 9 for heating the air before it enters the tumbler 1 ; a bleed of valve 10 for bleeding off the air to create a partial vacuum in the tumbler 1 ; and a secondary heat exchanger 14 for cooling the air before the separator. 7. Thermodynamically Reversible (Version 2 Only): The process described in FIG. 5 is thermodynamically reversible. This means that in theory, assuming no friction, no turbulence, a perfect heat exchanger and no temperature difference between the clothes and the condensate, zero energy is required to dry clothes. Water leaves the system in liquid form, that is, in the same phase as it enters it and therefore no energy needs to be spent on vaporizing water. Of course, in practice, the process includes friction and turbulence and needs to be driven forward and therefore, energy must be expended. However, the proposed technology has the potential for requiring significantly less energy than any other competing clothes drying technique. 8. Hybrid Operation Possible. The proposed dryer can easily incorporate features from other approaches such as a heater and vacuum. 9. Modular Construction Possible. The proposed dryer can be modular, with the tumbler, heat exchanger and pump/venture or compressor/turbine constructed in module to be assembled on board.
References: Design and Experimental Study of High-Speed Low-Flow-rate Centrifugal Compressors by Fulin Gui, Thomas R. Reinarts, and Robert P. Scaringe, Mainstream Engineering Corporation, and Joseph M. Gottschlich USAF Wright Laboratory. IECEC Paper No. CT39, ASME 1995.
Even though the description above is directed to a dryer for clothes, it should be clear to anyone versed in the arts that the same technology can be used to dry a wide diversity of other objects.
While the above description contains many specificities, the reader should not construe these as limitations on the scope of the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision many other possible variations within its scope. Accordingly, the reader is requested to determine the scope of the invention by the appended claims and their legal equivalents, and not by the examples which have been given.
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This invention is a method and apparatus for drying wet objects, comprising passing air through the wet objects thereby having air absorb moisture from said wet objects; compressing the air adiabatically, thereby heating it; extracting heat from the air by passing it through the hot side of a heat exchanger thereby cooling it; expanding the air adiabatically, thereby cooling it further, below its dew point; separating the condensate from the air; restoring to the air all or part of the heat by passing it through the second side of the heat exchanger; and redirecting all or part of the air back to the wet objects thereby forming a loop in the flow of the air.
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This is a nationalization of PCT/DK04/000084 filed Feb. 4, 2004 and published in English.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a package for a collecting bag to be secured to the abdomen of a patient or to a body side ostomy member for collecting fluids or excretions emerging from an abdominal stoma and the preparation thereof.
In connection with surgery for a number of diseases in the gastro-intestinal or urinary tract a consequence is, in many cases, that the colon, the ileum or the ureter has been exposed surgically and the patient is left with an abdominal stoma, or, in nephrostomy or ureterostomy, the ureter or a catheter is exposed in the back or the chest region or abdominal region, and the effluents or waste products of the body, which are conveyed through these organs, are discharged through the artificial orifice or opening and are collected in a collection bag, which is usually adhered to the skin by means of an adhesive wafer or plate having an inlet opening for accommodating the stoma/ureter/catheter. Also in connection with a fistula, the patient will have to rely on an appliance to collect the bodily material emerging from such opening.
Ostomy appliances are well known. Such appliances may be two-piece or one-piece appliances. In both types of appliances, an adhesive barrier member (or base plate) is attached to the wearer's abdomen/back/chest. In case of a one-piece appliance, a receiving member or bag is attached to the base plate. In case of a two-piece appliance, the adhesive barrier member forms part of a body side member and a receiving member or bag is attached releasably to the body side ostomy member for receiving exudates from the stoma.
When using one-piece appliances, the whole appliance, including the adhesive skin barrier securing the appliance to the skin is normally removed and replaced by a fresh appliance. When using two-piece appliances, the body side ostomy member is left in place up to several days, and only the receiving member or bag attached to the body side member is replaced. The attachment means for attaching an ostomy receiving bag may e.g. be a system comprising matching coupling rings or matching flanges and adhesive surfaces engaging with and sealing against a flange area of the body side member.
A known major problem with such receiving bags is that it can be difficult to dispose of the used bag in a convenient and hygienic manner. Some ostomists will cut the used bags open, e.g. by cutting off an edge thereof and deposit the contents into a WC for flushing away and dispose or deposit the empty bag in a waste bin. Such disposal of used bags and the contents therein is indeed unhygienic and unpleasant for the user, and the problems with disposal of a used bag is even more pronounced if the user does not have access to normal toilet facilities, e.g. when travelling.
SUMMARY OF THE INVENTION
The present invention relates to a package for a disposable ostomy receiving bag.
The invention also relates to a method of producing a package for containing a disposable ostomy receiving bag.
The present invention is described with reference to use in connection with an ostomy collecting bag but other uses of the package overcoming corresponding problems are also considered a part of the invention, e.g. the use in connection with handling hygienic articles such as sanitary towels or diapers.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is disclosed more in detail with reference to the drawings, in which
FIG. 1 shows a front view of a package of the invention comprising an ostomy appliance,
FIG. 2 shows a first stage in a process for preparing a package of the invention containing an ostomy appliance,
FIG. 3 shows a second stage in a process for preparing a package of the invention containing an ostomy appliance,
FIG. 4 shows a third stage in a process for preparing a package of the invention containing an ostomy appliance,
FIG. 5 shows an alternative way of folding the package, and
FIG. 6 shows a cross-sectional view of the package folded according to the present invention.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The present invention relates to a package for a disposable ostomy receiving bag, said package comprising a first compartment capable of accommodating a (fresh) ostomy receiving bag and a second compartment capable of accommodating a used ostomy receiving bag, said second compartment being sealable so as to confine the receiving bag, wherein the package is in the form of a bag having an open end and a cavity, the cavity defining the second compartment and wherein the bag is folded so as to define the first compartment.
In one embodiment the folded bag defines at least three folded edges.
The bag of the invention facilitates the handling of fresh and used bags and renders the user more independent on immediate availability of a lavatory or toilet facilities when having to substitute a bag while being out of the daily whereabouts. Thus, the invention renders it easy for an ostomate to carry a fresh bag in a discrete manner and also to handle the used bag in a safe and discrete manner reducing the risk of embarrassing situations in case of a leak liberating odour or the contents of the bag. This will increase the chances of living a more normal social life and increase the quality of life of the ostomate.
The package of the invention may be used for receiving bags for both one-piece and two-piece applications.
Suitable materials for a package of the present invention are thin flexible sheet materials, which are moisture resistant and impervious to liquids and preferably also odours, e.g. polyolefins such as polyethylene or polypropylene, EVA, polyvinylidene chloride, or chlorinated polyethylene or copolymers of PE and EVA or combinations of such foils. The walls of the bag may in a special embodiment be laminated with materials conventionally used in the production of ostomy appliances such as non-woven materials of polyethylene, polypropylene or a polyester.
The package for a disposable ostomy receiving bag, is in the form of a bag. The second compartment of the package is constituted by the bag which has an opening defining the entrance of said second compartment. The bag may have a first wall and a second wall of sheet material which could be attached to each other by means of glue, welding or any other suitable means of attachment. When the first and second walls are attached to each other they define the inner surfaces of the cavity and thus the inner walls of the second compartment.
Seen from one side the bag may have any shape such as rectangular, triangular or any other polygonal shape or e.g. a semi-circle. The circumference of the opening may be larger than the circumference of any other part of the cavity. In another embodiment the circumference of the opening is smaller than the circumference of at least a part of the cavity.
In order to define the first compartment the bag is folded. When the bag, and thereby the second compartment, is defined by a first and second wall, the inner surfaces of the first compartment is defined by the outer surface of the first wall. Seen from the patient/skin side of the package the order of the materials/compartments may thus be
1) second wall
2) second compartment
3) first wall
4) first compartment
5) first wall (first folded part)
6) second wall (first folded part)
if the folded slips overlap each other the following is furthermore added to the order of the materials
7) first wall (second folded part)
8) second wall (second folded part)
as 5) and 6) defines one slip and 7) and 8) the other slip.
A suitable embodiment of a package is in the form of a bag having a closed end and an open end and having a first wall and a second wall, said bag having edges connecting the closed and open ends of the bag wherein the edges are folded so as to cover each a longitudinal strip of the first wall, said bag also being folded so that the closed end of the first wall is parallel to the open end of the first wall to form the first compartment. To prevent a fresh ostomy appliance confined by the first compartment from falling out, the opposing sides of the first wall may be connected with releasable adhesive dots or a releasable label may be applied across the opening of the first chamber. In this embodiment, a relatively large bag which may accommodate a used bag with contents is also rendered suitable for accommodating a fresh receiving bag and, at the same time, ensures as high a degree of discretion as it may e.g. be carried in a hand bag or a pocket. It is preferred that the material for a package of the invention is opaque for blurring the contents for improving the discretion when it is necessary to carry the package containing a used bag. Furthermore, the bag is easy to unfold without risk of damaging the walls of the bag compromising the later use for carrying the used bag.
It is preferred that the closed end of the bag, in its folded position, leaves a part of the open end of the bag free as a flap capable of covering the inlet opening of the compartment when folded as this flap will protect a fresh bag against mechanical damage when stowed in a hand bag or a pocket.
In accordance with another preferred embodiment, one of the walls of the open end of the bag (the one being at the outside after folding the bag) is extended beyond the edge of the other wall forming an extended flap, which may have a general rectangular, triangular or oval shape or the shape of a part of a circle.
The safety against damage and unintended catching of the bag is increased when the flap and the outer surface of the second wall forming the first compartment are provided with means for releasable attachment of the flap to the surface of the wall. Such means may be a releasable adhesive sealing or a peelable weld seam. The sealing of the first compartment may preferably be effected using an adhesive label placed on the flap. Such a label may also be used in a manner known per se for carrying information identifying the product.
Due to the stiffness of the double folding and the supporting effect of the ostomy appliance, an unintended unfolding of the bag and opening of the first compartment and uncovering the ostomy appliance may be ensured alone by applying an adhesive label without having to rely on further sealing of the package of the invention.
The second compartment of the package is advantageously sealed by tying a knot on a part of the open end or using another suitable sealing means such as a clamp known per se for sealing an ostomy bag or an adhesive sealing which is preferably covered by a protecting release liner made from a suitable material such as polyethylene or a siliconised paper to be removed before use or a reusable adhesive placed on the flap. When a reusable adhesive is used on the flap for closing the first compartment, this may also be used for closing the second compartment in which the used receiving bag is then safely confined.
The package may be made from a bag made from a thermoplastic material in a manner known per se. It is preferred that the edges are folded so as to cover each a longitudinal strip of the first wall having a width of from 15% to 50% of the total width of the bag, preferably from 25% to 40% of the total width of the bag, e.g. from 30% to 35% which together with the stiffness of the ostomy appliance will be sufficient to prevent an unintended unfolding of the bag and opening of the first compartment and uncovering the ostomy appliance when sealing the first compartment using an adhesive label.
A safe and discrete depositing of the used bag when having to rely on using a waste bin is secured when the bag is made from a material being substantially impervious to odour. A suitable such material is a material conventionally being used for production of ostomy appliances, e.g. the ones mentioned above.
In another (second) aspect the invention relates to a method of producing a package containing a disposable ostomy receiving bag, said package comprising a first compartment capable of accommodating a (fresh) ostomy receiving bag and a second compartment capable of accommodating a used ostomy receiving bag, said second compartment being sealable so as to confine the receiving bag, said method comprising placing an ostomy appliance on a bag having a closed end and an open end and having a first wall and a second wall and said bag having edges connecting the closed and open ends of the bag wherein the edges are folded so as to cover each a longitudinal strip of the first wall and a part of the ostomy appliance, and subsequently folding the closed end of the first wall of said bag so that is parallel to the open end of the first wall and covers the folded strips and the ostomy appliance to form the first compartment.
The package of the second aspect may be in the form as described in claim 1 wherein the wherein the package is in the form of a container bag having an open end and a cavity, the cavity defining the second compartment and wherein the container bag is folded so as to define the first compartment. The package may be folded such that the edges of the closed end and the open end are not necessarily parallel but may be transverse to each other. However it is essential that the package is folded so as to define the first compartment.
It is preferred that the bag is folded so that the closed end of the bag, in its folded position, leaves a part of the open end of the bag free as a flap which is then folded to cover the inlet opening of the first compartment.
In a preferred embodiment, the flap is then secured to the outer surface of the second wall for closing the first compartment by means for releasable attachment of the flap to the surface of the wall.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention is now explained more in detail with reference to the drawings showing preferred embodiments of the invention.
Reference is made to FIGS. 1 and 4 showing a front view of an embodiment of a package of the invention is in the form of a bag 1 having a closed 2 end and an open end 3 and having a first wall 4 and a second wall 5 and said bag having edges 6 , 6 ′ connecting the closed and open ends of the bag wherein the edges are folded so as to cover each a longitudinal strip 7 , 7 ′ of the first wall, said bag subsequently being folded so that the closed end of the first wall is parallel to the open end of the first wall to form the first compartment. The first compartment comprises an ostomy appliance 8 and is open in FIG. 3 and closed in FIG. 4 in which the first compartment is also sealed using an adhesive label 9 . FIGS. 2 and 3 show stages one and two in a process for preparing a package of the invention comprising an ostomy appliance, FIG. 4 showing a third stage and FIG. 1 the finished package.
In a method of producing a package of the invention containing a disposable ostomy receiving bag, said package comprising a first compartment capable of accommodating a (fresh) ostomy receiving bag and a second compartment capable of accommodating a used ostomy receiving bag, said second compartment being sealable so as to confine the receiving bag, said method comprising in a first stage placing an ostomy appliance 8 on a bag 1 having a closed end 2 and an open end b and having a first wall 4 and a second wall 5 and said bag having edges 6 , 6 ′ connecting the closed 2 and open 3 ends of the bag wherein the edges 6 , 6 ′ are folded so as to cover each a longitudinal strip 7 , 7 ′ of the first wall 4 and a part of the ostomy appliance 8 , and then folding the closed end 2 of the first wall 4 of said bag so that is parallel to the open 3 end of the first wall and covers the folded strips and the ostomy appliance leaving the upper end of the bag forming a flap 10 to form the first compartment. Then, the first compartment closed by folding the flap 10 so that the first wall contacts the outer surface of the second wall 5 , said compartment encasing an indicated ostomy receiving bag 8 , the outer surface of the second wall and further being provided with an adhesive label 9 for closing the first compartment
When using the package of the invention, the ostomate breaks the seal of the flap, opens the first compartment and removes the fresh ostomy receiving bag for substituting the one in use. Then, the first compartment of the bag is unfolded giving access to the full space of the package forming the second compartment. After detaching the used receiving bag from the abdomen or from an ostomy body side member, the bag may be placed in the second compartment with or without emptying the bag as is appropriate. Then the package is advantageously sealed by tying a knot on a part of the open end or using another suitable sealing means such as a clamp known per se for sealing an ostomy bag or an adhesive sealing which is preferably covered by a protecting release liner made from a suitable material such as polyethylene or a siliconised paper to be removed before use or a reusable adhesive placed on the flap. When a reusable adhesive is used on the flap, this may also be used for closing the second compartment in which the used receiving bag is then safely confined.
In FIG. 5 is seen a package 30 folded prior to the folding process which defines the first compartment (not shown as the package in this figure is not folded according to claim 1 ) which is next to second compartment 32 . The package comprises a first wall 34 and a second wall 36 which are attached to each other along an edge 38 . Prior to the folding according to claim 1 , the edges 38 are folded in inwards such that the area of the first wall 34 and the second wall 36 visually seems to be smaller, as a part of the walls are hidden inside the bag. Edges on the sides and/or the bottom may be folded this way.
Afterwards the package is folded as described previously such that the lines 40 becomes the outer edges of the package in the folded state.
FIG. 6 shows a cross-sectional view of the bag folded according to the present invention. The bag 50 comprises a first wall 52 and a second wall 54 attached to each other in edges 56 . The order of materials/compartments along the direction indicated by arrow 58 is
1) second wall 54
2) second compartment 60
3) first wall 52
4) first compartment 62
5) first wall (first folded part) 52
6) second wall (first folded part) 54
7) first wall (second folded part) 52
8) second wall (second folded part) 54
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A package for a disposable ostomy receiving bag, said package comprising a first compartment capable of accommodating a (fresh) ostomy receiving bag and a second compartment capable of accommodating a used ostomy receiving bag, said second compartment being sealable so as to confine the receiving bag facilitates the handling of fresh and used bags and renders the user more independent of the availability of a lavatory.
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This application is a divisional of U.S. Ser. No. 08/806,207 filed Feb. 26, 1997, now U.S. Pat. No. 5,778,841.
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a camshaft for an internal combustion engine and more particularly, to a hollow camshaft for reducing the overall weight of an engine and effectively supplying lubricant to camshaft journal bearings.
BACKGROUND OF THE INVENTION
In an effort to remain competitive, engine manufacturers are continuously seeking ways to improve the efficiency and reliability of their engine products without compromising performance. Through research and innovation, manufacturers are continuously attempting to reduce manufacturing costs, yet provide the customer with a reliable and efficient product that meets or exceeds their needs. A known technique for achieving greater efficiency, especially in engines used in over-the-road vehicles, is to reduce the weight of such engines. Such weight reduction can lead to greater fuel efficiency, reduced tire wear, and other reduced costs associated with manufacture and use of the engine product.
The camshaft of an internal combustion engine has evolved through the years to meet ever increasing performance requirements, e.g. increased stress tolerances, need for longer durability, and cost effective manufacture. In certain types of engines, such as diesel engines used in over-the-road commercial trucks, manufacturers have increased injection pressures to improve the performance, efficiency and lowered emissions to meet governmentally mandated standards. However, these high injection pressures have significantly increased stress tolerances and torsional loads on such engine cam shafts. Increasing the camshaft's diameter is one way to meet such increased demand. One problem associated with using a large diameter camshaft, however, is the amount of weight it adds to the engine. Hence, at least some of the benefits associated with a camshaft of unusually large diameter could be lost unless its weight is minimized.
Another problem faced by engineers in the engine industry is designing an engine that provides an adequate amount of lubricant to the camshaft and camshaft bearing journals in order to cool these parts, reduce undesired friction and minimize wear during engine operation. If any of these factors are not met, the engine could suffer substantial damage and possibly engine failure.
Certain engine manufacturers have attempted to develop hollow camshafts to reduce the weight of the engine while trying to provide adequate lubrication to the camshaft journal bearings. For example, U.S. Pat. No. 4,957,079 to Nakatani et al. discloses an exhaust overhead camshaft formed with an axial oil passage extending along substantially its entire length and communicating with radial oil passages formed in the camshaft bearing journals. An oil passage extends upward from midway of a laterally extending oil passage and opens to an annular groove of a plain split thrust bearing for the exhaust overhead camshaft. The engine lubrication oil flows through the oil passage and into the annular groove of the plain split thrust bearing for the exhaust overhead camshaft, to oil the thrust collars. The lubricating oil passing up to the thrust collars further flows, through the radial oil passages formed in the thrust collars, into the axial oil passage in the camshaft. The radial oil passages formed in the camshaft bearing journals of the camshaft allow the lubricating oil to flow in the axial oil passage to lubricate the bearings of the camshaft.
The '079 Nakatani patent discloses only one inlet for lubricant to flow into the axial oil passage of the camshaft which limits the volume and distribution of lubricant to the camshaft bearing journals during engine operation. In addition, if the one inlet of Nakatani becomes clogged, no lubricant would be available for the camshaft bearing journals potentially causing severe engine problems. In addition, the structural design of the Nakatani camshaft does not allow for even distribution of lubricant from the engine head to the camshaft journal bearings since lubricant is introduced only at one end of the camshaft. As stated above, it is imperative that lubricant is allowed to enter into the camshaft unimpeded to prevent any clogging or other undesirable event which could impair fluid communication between engine parts and impair adequate lubrication of critical engine parts.
By creating a hollow camshaft structure including a hollow shell with radial holes formed therein, a manufacturing engineer must consider torsional and other load influences on the camshaft body during engine operation. A hollow camshaft used in a large, heavy duty engine environment must be able to withstand high injection pressures and other stress-related forces which can over stress or even break the camshaft. Therefore, the hollow camshaft must be formed in a way that reduces the impact of torsional loads exerted on the camshaft during engine operation while providing adequate lubrication to the camshaft journal bearings. The '079 patent does not suggest the desirability of maximizing the volume and selecting the shape of the hollow interior to reduce thereby the weight of the camshaft while also producing adequate strength and other operating characteristics as discussed above.
One reference which focuses on this problem is U.S. Pat. No. 4,072,448 to Loyd, Jr. which discloses holes formed in a camshaft body to allow lubricant to flow therethrough. Each of the holes are formed spaced apart in different planes in the camshaft body. The formation of the holes in this manner improves the load characteristics of a hollow camshaft. However, the structural design of the Loyd camshaft does not insure adequate fluid communication and distribution to the camshaft journal bearings and other critical areas of the camshaft.
It is evident, based on the references discussed above, no hollow camshaft has been developed which provides effective fluid communication between the engine cylinder head, camshaft and camshaft journal bearings while operating under high injector pressures and torsional loads.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide an improved high strength, lightweight camshaft which facilitates effective lubricant flow between an engine cylinder head, camshaft and camshaft journal bearings while facilitating high performance engine operation.
It is also an object of the present invention to achieve the above object and to provide an improved high strength, lightweight camshaft that reduces expensive-to-manufacture lubricant drillings within the cylinder head that would normally be required to accomplish lubricating the camshaft journal bearings.
It is another object of the present invention to achieve one or more of the above objects, and to provide an improved high strength, lightweight camshaft for use in an internal combustion engine wherein a supply a lubricant always remains in the camshaft to aid in lubricating bearings during engine start-up conditions.
It is further an object of the present invention to achieve one or more of the above objects, and to provide an improved high strength, lightweight camshaft having a hollow interior formed in the camshaft body for receiving lubricant from an engine cylinder head and effectively transferring the lubricant to at least one camshaft journal bearing during engine operation.
It is also an object of the present invention to achieve one or more of the above objects, and to further provide an improved high strength, lightweight camshaft having at least a pair of camshaft journal bearings positioned adjacent the ends of the camshaft body which include a lubricant transfer means for providing at least two paths for lubricant to flow into the hollow interior of the camshaft to insure even distribution of lubricant to the camshaft journal bearings.
It is still another object of this invention to provide a camshaft having a drive gear mounting at one end and plural journal bearings located at spaced apart positions along the axial length of the camshaft wherein the camshaft has a hollow interior extending along substantially its full axial length, but the effective diameter of the hollow interior is substantially less from the drive gear mounting end to the second bearing journal closest to the drive gear mounting end as compared with the effective diameter of the hollow interior along the remainder of the camshaft to minimize total weight of the camshaft while providing adequate distortion resistant strength at the drive gear mounting end of the camshaft.
It is a yet another object of the present invention to achieve one or more of the above objects and also provide an improved high strength, lightweight camshaft having radial holes formed in different axial planes of the camshaft body to minimize the impact of torsional and other stress-related loads on the camshaft body during engine operation.
It is also another object of the present invention to achieve one or more of the above objects and also provide an improved high strength, lightweight camshaft having a camshaft body capable of withstanding at least a minimum bending stress of 10,000 psi with minimal camshaft deformity.
It is a further object of the present invention to achieve one or more of the above objects and also provide an improved high strength, lightweight camshaft having a hollow interior diameter between 24 percent and 59 percent of the camshaft body diameter.
These, as well as other objects of the present invention, are achieved by a high strength, lightweight camshaft for an internal combustion engine, comprising a shaft body having an axially oriented hollow interior extending a predetermined length from between a pair of spaced points, respectively, adjacent the ends of the shaft body. Plural camshaft journal bearings are spaced apart on the shaft body and include a pair of end camshaft journal bearings positioned adjacent the ends of the shaft body, respectively, with at least one inner camshaft journal bearing positioned intermediate the pair of end camshaft journal bearings. Each end camshaft journal bearing has a lubricant transfer means formed therein for receiving lubricant from an external supply and for transferring lubricant into the hollow interior of the camshaft. At least one radial hole is formed in the shaft body for providing lubricant from the hollow interior to an inner camshaft journal bearing wherein the lubricant transfer means associated with the pair of end camshaft journals provides at least two paths for lubricant to flow into the hollow interior of the camshaft for providing an even distribution of lubrication to each inner camshaft journal bearing during operation of the internal combustion engine.
The camshaft body includes an axial passage extending from an end of the shaft body to the hollow interior to allow fluid communication between the axial passage and hollow interior. A cap and a plug are secured to the respective ends of the shaft body for preventing lubricant leakage from the axial passage and hollow interior, respectively. A supply of lubricant always remains in the camshaft to assist in lubricating the camshaft journal bearings during engine start-up.
The lubricant transfer means includes a groove which radially extends along the outer surface of each end camshaft journal bearing and a flow passage for allowing fluid to communicate between an external supply and the hollow interior via the groove. Radial holes are equal angularly arranged about the circumference of the camshaft body. These radial holes intersect the hollow interior of the camshaft to allow fluid communication.
In addition, the camshaft is arranged to be rotatably mounted on an engine head and supported thereon by a plurality of bearing collars located in spaced apart positions along the axial length of the camshaft. The camshaft also has a camshaft journal bushing positioned in an abutting relationship between at least one of the camshaft journal bearings and at least one of the plurality of collars. The camshaft journal bushing has a radial opening formed therein to allow lubricant to flow therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is an elevational view of a camshaft in accordance with a preferred embodiment of the present invention;
FIG. 1b is a cross-sectional view of the camshaft of FIG. 1a in accordance with a preferred embodiment of the present invention;
FIG. 2 is a perspective view of a cylinder head for an internal combustion engine in accordance with a preferred embodiment of the present invention;
FIG. 3 is side elevational view of the cylinder head of FIG. 2 and the camshaft of FIG. 1 in accordance with a preferred embodiment of the present invention;
FIG. 4 is a cross-sectional view of a camshaft positioned in a cylinder head in accordance with a preferred embodiment of the present invention;
FIG. 5 is perspective view of a camshaft journal bushing identified in FIG. 4 in accordance with a preferred embodiment of the present invention; and
FIG. 6 is a partial cross-sectional view of a diesel engine illustrating the camshaft of FIGS. 1 and 2 mounted within the engine head of FIG. 2 and arranged to cyclically operate an engine unit injector through a rocker arm and link.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is directed to a high-strength, light-weight camshaft for use in an internal combustion engine, particularly for use in compression-ignition engines equipped with high pressure, cam operated, unit fuel injectors. The camshaft is designed to withstand high bending and torsional loads while producing high injection pressures and increased engine power to improve the performance of vehicles, such as over-the-road commercial trucks, in which the camshaft is used. By increasing the pressure of fuel, such as liquid diesel fuel, as it is injected into a combustion chamber, the fuel is mixed more thoroughly with the charge air within the combustion chamber. Ideally, the fuel and charge air are homogeneously mixed prior to ignition. Injection pressures of about 18,000 psi, and as high as 25,000 psi, help promote better mixing of the fuel and charge air. Better mixture of fuel and charge air not only helps to reduce undesired emissions, such as smoke and unburned hydrocarbons, but also significantly improves engine power and efficiency. High fuel injection pressures can be obtained by the use of cam operated unit fuel injectors such as disclosed in a variety of patents issued to Cummins Engine Co., Inc., assignee of the subject invention. For example, note U.S. Pat. Nos. 4,721,247; 4,986,472; and 5,094,397.
One of the factors imposing limitations on increased fuel injection pressure is the inability of cam surfaces to withstand surface pressure above a certain limit without failure or excessive wear. Another limitation is the ability of a camshaft to avoid excessive bending stress and excessive bearing wear. One technique for overcoming, to some degree, these limitations is to increase the diameter of the cam to increase the cam surface area and the strength of the camshaft. A camshaft of increased size and rigidity permits the camshaft to withstand the significantly greater bending and torsional loads imposed when the injection pressure is increased. In FIG. 6, for example, a cam 61 attached to a camshaft may be used to actuate a rocker arm 63 which, in turn, actuates the plunger of a high pressure fuel injector 65 via link 67 used in a diesel engine. Rocker arm 63 is pivotally mounted on a support rod 69 which is positioned in a rod mounting 66 (shown partially in FIG. 3) attached to an engine cylinder head. One revolution of the camshaft moves rocker arm 63 a distance d, shown in FIG. 6, between a first and second position, to actuate the plunger of high pressure fuel injector 65 and inject fuel under high pressure into an engine cylinder (not shown) through an injector nozzle to form fuel spray patterns 68a-68d. A cam increased in diameter allows the fulcrum of the rocker arm to be moved closer to the injector, thus, increasing the distance "y" and decreasing the distance "x" illustrated in FIG. 6, to provide an increased mechanical advantage (thereby allowing greater injection pressure) without increasing pressure on the cam surfaces. Thus, in accordance with one aspect of the subject invention, a camshaft having a relatively large diameter is able to generate the desired injection pressures while withstanding the bending and torsional loads acting thereon.
By simply increasing the diameter of the camshaft to obtain the benefit of high injection pressure, however, the weight of the engine would be undesirably increased. The present invention provides a camshaft of sufficient size and rigidity to withstand high injection pressures without significantly adding weight to the internal combustion engine. In addition, the camshaft of the present invention facilitates even distribution of lubricant to vital engine parts during all stages of engine operation, including start-up, in order to reduce wear and also to reduce manufacturing costs normally associated with conventional camshaft designs. The present invention, as used in the environment described above, is explained in detail below with reference to FIGS. 1-5.
FIGS. 1a and 1b provide an elevational and cross-sectional view, respectively, of a camshaft designed in accordance with the preferred embodiment of the present invention. Specifically, FIG. 1a illustrates a camshaft 1 which is dedicated exclusively to operate a plurality of unit injectors in timed synchronization with the reciprocal movement of corresponding pistons within the cylinders of a compression ignition engine. Camshaft 1 comprises a camshaft body 3 having a tubular shape. Camshaft body 3 includes a series of injector cams or lobes 5a-5f and camshaft journal bearings 7a-7g spaced equidistant apart in an alternating pattern beginning from a first end 6 to a second end 8. A plurality of grooves 9 separate the injector lobes and camshaft journal bearings. The minimum cross-sectional diameter of camshaft body 3 occurs within the trough of each groove 9. The minimum diameter is significant in determining the maximum bending and torsional stress limits of camshaft 1 as discussed in greater detail below. Each of the camshaft journal bearings 7b-7f includes radial holes 11a-11e formed therein. Radial holes 11a-11e extend perpendicularly with respect to the camshaft axis and provide a passage that delivers lubricant to each of camshaft journal bearings 7b-7f during engine operation.
Camshaft journal bearings 7a and 7g are positioned adjacent to first end 6 and second end 8, respectively. Moreover, camshaft journal bearings 7a and 7g include lubricant transfer grooves 13a and 13b which radially extend along the central perimeter of each camshaft journal bearing. Flow passages 15a and 15b (FIG. 1a) are formed within camshaft body 3 to provide fluid communication from lubricant transfer grooves 13a and 13b, respectively, into the hollow interior of camshaft body 3. First end 6 of camshaft body 3 includes a tapered portion 10 formed thereon to allow a camshaft drive gear (not shown) to be mounted onto camshaft body 3 for rotatably driving the camshaft. The drive gear forms part of a gear train (not illustrated) mounted on the end of the engine and is driven by a drive gear mounted for rotation with the crankshaft of the engine. Camshaft body 3 further includes a timing lobe 2 and a fuel system gear lobe 4 positioned between camshaft journal bearing 7e and injector lobe 5d, and camshaft journal bearing 7c and injector lobe 5c, respectively. Timing lobe 2 is used to track the rotational position of the camshaft at a particular time. Fuel system gear lobe 4 is formed on camshaft body 3 to drive a fuel pump (not shown) in an internal combustion engine.
FIG. 1b is a cross-sectional view of camshaft 1 illustrated in FIG. 1a. As shown in FIG. 1b, camshaft body 3 includes an axially oriented hollow interior 21 which extends from camshaft journal bearing 7b to second end 8. Hollow interior 21 may be formed by an axial drilling or other manufacturing process. An axial passage 23 is also formed in camshaft body 3 and extends from first end 6 to camshaft journal bearing 7b, where axial passage 23 intersects hollow interior 21. Camshaft body 3 is hollowed from first end 6 to second end 8, as illustrated in FIG. 1b, to allow lubricant to freely flow therethrough.
The inner cavity of camshaft body 3, namely hollow interior 21 and axial passage 23, is sealed at both ends to prevent lubricant from escaping therefrom. At first end 6, a capscrew 25 is provided to mount the camshaft drive gear (not shown) as well as to effectively seal off axial passage 23 extending through camshaft body 3. Likewise, an expansion plug 27 is provided at second end 8 to seal off hollow interior 21. Alternatively, a pressure plug or other type of sealing device may be used to seal off hollow interior 21, however, expansion plug 27 is preferred. With the use of capscrew 25 and expansion plug 27, the inner cavity of camshaft body 3 is effectively end sealed to ensure that a supply of lubricant always remains in camshaft 1 to aid in lubricating camshaft journal bearings 7b-7f through radial holes 11a-11e during engine start-up conditions. Normally, when an engine is cranked, engine parts immediately contact one another before lubricant is fully supplied, resulting in undesired bearing surface engine wear. By supplying lubricant immediately to the camshaft journal bearings during engine start-up, engine wear can be significantly reduced over the life of the engine, thus, reducing maintenance cost and undesired downtime. An oil return passage 29 is also formed in camshaft body 3 to drain any oil which leaks from camshaft journal bearing 7g and becomes trapped between second end 8 and an end cap (not shown) during engine operation. Oil return passage 29 prevents build-up of fluid pressure between second end 8 and the end cap (not shown) due to the oil leakage.
Hollow interior 21 and axial passage 23 allow camshaft 1 to have an increased outer cross-sectional diameter without adding excessive weight to the engine. Therefore, the benefits of camshaft body 3 as explained herein can be realized without any undesired effects. In particular, the exterior diameter of each injection cam or lobe 5a-5f can be increased in diameter to allow substantially increased injection pressure without exceeding the limit of cam surface pressures and without exceeding the torsional and bending stress limits of the camshaft. At the same time, engine weight is held within acceptable limits by providing the maximum possible hollow interior volume. In particular, camshaft body 3 is designed to withstand the high bending and torsional loads that necessarily result from increasing the pressure at which fuel is injected. To accomplish this without excessive weight increase, hollow interior 21 is formed with the maximum possible diameter from camshaft journal bearing 7b to the second end 8 of the camshaft body 3. The portion of camshaft body 3 extending from first end 6 to camshaft journal bearing 7b includes axial passage 23, which has a significantly smaller diameter than hollow interior 21, thus, resulting in a thicker camshaft portion at the first end of camshaft body 3. This feature of the present invention is critical, since first end 6 experiences higher torsional and bending loads than second end 8 due to the force exerted by the cam drive gear (not shown) which attaches to camshaft body 3 at first end 6. By having a smaller axial passage in the portion of camshaft body 3 connected to a cam gear (not shown), the camshaft has increased rigidity at its first end between the first and second camshaft bearings 7a and 7b to ensure that undesired bending stresses and torsional loads do not adversely impact camshaft body 3 when generating high injection pressures. Furthermore, radial holes 11a-11c are arranged angularly about the circumference of camshaft body 3 to minimize the impact of stress and torsional loads on the camshaft. Thus, the present invention achieves a high-strength. lightweight camshaft that is designed to counteract any adverse bending or torsional stresses while having the necessary size to create high injection pressures for optimal engine performance.
In a preferred embodiment, the diameter of camshaft journal bearings 7a-7g, illustrated in FIG. 1a, is approximately 85 millimeters; however, depending on the desired injection characteristics, the diameter of camshaft journal bearings 7a-7g could range between 70 millimeters and 100 millimeters. The inner surface of groove 9, in the preferred embodiment, is 58 millimeters. As with the diameter of the camshaft journal bearings, this diameter may vary depending on the desired injection response. The preferred diameter of the hollow interior is 40 millimeters with a length of approximately 850 millimeters. However, the inner diameter may range between 20 millimeters and 50 millimeters, depending on a particular camshaft application. For most practical applications, the inner diameter of the hollow interior may be between 24% and 59% of the diameter of the camshaft journal bearings, however, in the preferred embodiment, the percentage is approximately 47%.
Camshaft 1 preferably has a length of approximately 1,104 millimeters and weighs approximately 64 pounds. This camshaft is designed to be used with a 6-cylinder engine and may be modified to accommodate an engine having a smaller or a larger number of cylinders, as desired. The camshaft of the preferred embodiment is preferably formed from steel and is capable of withstanding at least a minimum bending stress of 10,000 pounds per square inch (psi). The camshaft, however, may be formed from other suitable materials, such as cast iron, depending on the desired characteristics and applications.
Certain factors to consider in forming camshaft 1 to meet a specific application are discussed in detail below. These factors may include stress, moment, and moment of inertia which are used to calculate the camshaft's ability to withstand bending loads. A mathematical representation of these factors using the inside diameter of hollow interior 21 and the inner surface diameter of groove 9 is provided. Depending on the combination of diameters, and based purely on bending stress, the equations below could be used to cover a range of practical applications based on the camshaft size and desired rigidity.
When considering only pure bending, the following parameters are used:
σ--Stress
m--Moment (Force×Distance)
I--Moment of Inertia
d 1 --Inner surface diameter of groove 9
d 2 --Inside diameter of hollow interior 21
C--Radius of groove 9 (C=d 1 /2)
Bending stress is determined by:
σ.sub.B =MC/I
wherein
I=π/64(d.sub.1.sup.4 -d.sub.2.sup.4)
Substituting I into the equation for bending stress:
σαMC/(d.sub.1.sup.4 -d.sub.2.sup.4)
Practical diameter values of the inner surface diameter of groove 9 (d 1 ), the inside diameter of hollow interior 21 (d 2 ) and radius (C) are provided below:
d 1 =58 mm
d 2 =40 mm
d 2 =20 mm
C=29 mm
Using the formula for stress and the variables defined above, a mathematical representation of bending stress with respect to a camshaft size (inner and outer diameters) is provided below:
To determine bending stress using d 2 =40 mm:
σαM(29)/(58).sup.4 -(40).sup.4 (64/π)
σd.sub.1 α67.47×10.sup.-6 (M)1/mm.sup.3
Substituting 67.47×10 -6 (M) 1/mm 3 in for σd 1 , the following equation for bending stress results (note that M cancels out):
67.47×10.sup.-6 =C/I
67.47×10.sup.-6 =C/π/64(d.sub.1.sup.4 -d.sub.2.sup.4)
where
C=d.sub.1 /2
To determine bending stress using d 2 =20 mm:
σαM(29)/((58).sup.4 -(20).sup.4)(64/π)
σd.sub.2 α52.95×10.sup.-6 (M)1/mm.sup.3
Substituting 52.95×10 -6 (M) 1/mm 3 in for σd 1 , the following equation for bending stress results (note that M cancels out):
52.95×10.sup.-6 =C/I
52.95×10.sup.-6 =C/π/64(d.sub.1.sup.4 -d.sub.2.sup.4)
where
C=d.sub.2 /2
The mathematical analysis presented above may be used to calculate the amount of bending stress a camshaft is able to withstand based on the inner surface diameter of the camshaft body (outer diameter) and the inner diameter of the camshaft's hollow interior. For example, using the diameters provided above, the bending stress σ of a camshaft having an inner surface diameter of 58 mm, a hollow interior diameter of 40 mm and a radius of 29 mm is approximately 67.47×10 -6 (M) 1/mm 3 , depending on the moment M. Thus the above equations could be used to determine the type of material from which the camshaft needs to be made or to allow the diameters d 1 and d 2 to be adjusted to insure that the camshaft will have adequate strength.
FIG. 2 is a perspective view of a cylinder head 31 for an internal combustion engine in accordance with the preferred embodiment of the present invention. Cylinder head 31 includes a cylinder head body 33 having two sets of collars 34a-34g and 35a-35g located in positions along the lateral sides of the head. These collars are spaced apart and rigidly attached to the head to form an axial mounting for two separate camshafts. Collars 35a-35g are formed to receive a more conventional type of camshaft for actuating the exhaust or intake valves associated with each engine cylinder. In contrast thereto, collars 34a-34g are arranged to receive a camshaft of substantially greater diameter, such as camshaft 1, formed in accordance with the subject invention, dedicated solely to driving the engine's fuel injectors through rocker arms, as illustrated in FIG. 6. Although cylinder head body 33 is designed to receive dual camshafts, only the mounting of camshaft 1 will be discussed herein. In addition, cylinder head body 33 merely illustrates one environment in which camshaft 1 may be used. One skilled in the art should recognize that camshaft 1 may be used in a variety of engine applications including a dual overhead cam design or a single cam design.
Camshaft 1 is rotatably mounted in cylinder head body 33 by inserting second end 8 of camshaft 1 through opening 37 formed in cylinder head body 33, and subsequently advancing camshaft 1 through collars 34a-34g until each of camshaft journal bearings 7a-7g is located within the respective collars 34a-34g as shown in FIGS. 3 and 4. Camshaft 1 is able to freely rotate within cylinder head body 33 when mounted and secured thereto by end plates (not shown). In addition to collars 34a-34g, cylinder head body 33 further includes lubricant passages 39a and 39b which are formed in the sidewalls of cylinder head body 33.
During engine start-up conditions, lubricating oil is pumped from an oil pan (not shown) located underneath the cylinder head and forced upward to lubricate vital engine parts during engine operation. The pump forces oil into lubricating passages 39a and 39b which deliver oil to a plurality of rocker arms (FIG. 6) through supply passage 47 of FIG. 2, camshaft 1 and ultimately camshaft journal bearings 7a-7g. Lubricating passages 39a and 39b terminate at lubricating grooves 43a and 43b, illustrated in FIG. 2, at which lubricant is transferred to camshaft 1. One advantage of the present invention is that lubricant is supplied to both ends of camshaft 1 simultaneously to provide an even distribution of lubricating oil to all the camshaft bearing journals during engine operation. This is critical in maintaining proper lubrication to reduce engine wear resulting from extreme temperatures and friction. The transfer of lubricating oil from cylinder body 33 to camshaft 1 will be described in greater detail with reference to FIGS. 4 and 5.
FIG. 4 is a cross-sectional view of camshaft 1 positioned in cylinder head 31 in accordance with a preferred embodiment of the present invention. This cross-sectional view is taken along line 4a--4a in FIG. 3. FIG. 4 specifically shows the manner by which camshaft 1 is rotatably mounted within cylinder head 31 and illustrates the manner by which lubricant is transferred into and out of the interior of camshaft 1 to insure adequate lubrication of the camshaft bearings at all stages of engine operation. Lubricant is transferred from engine cylinder head 31 to camshaft 1 via lubricating grooves 43a and 43b, which are respectively aligned with lubricant transfer grooves 13a and 13b with a camshaft journal bushing 55 (see FIG. 5) positioned therebetween. As shown in FIG. 5, the camshaft journal bushing 55 is a ring-shaped bushing having an aperture 59 formed therein. Lubricant flows through aperture 59 as it is transferred between lubricating passages 39a and 39b and lubricant transfer grooves 13a and 13b formed in camshaft journal bearings 7a and 7g, respectively. After lubricant travels into lubricant transfer grooves 13a and 13b, it flows through radial flow passages 15a and 15b and into axial passage 23 and hollow interior 21, respectively. Since an even flow of lubricant is introduced into each end of the camshaft, the inner cavity of camshaft 1 rapidly becomes fully pressurized with lubricant which is critical during engine start-up conditions. This pressurization forces lubricant into each of radial holes 11a-11e to lubricate camshaft journals 7b through 7f. Even before the lubricant is fully pressurized, the hollow interior 21 and axial passage 23 will have trapped lubricant upon previous termination of engine operation. This reservoir of lubricant will help insure that at least some lubricant reaches critical bearing surfaces before the engine's lubrication pump is able to provide sufficient lubricant to fully pressurize interior 21 and axial passage 23. Faster and more even pressurization occurs because lubricant is simultaneously supplied at opposite ends of the camshaft. Moreover, the redundancy also helps to insure adequate lubricant flow even if one of the supply passages were to become clogged.
The present invention introduces a novel approach of providing lubricant to camshaft journal bearings without requiring complex manufacturing techniques. In addition, the present invention provides a camshaft design that is simple to manufacture, reduces the weight of an engine, facilitates adequate lubrication to vital engine parts, and is able to facilitate high injection pressures resulting in increased engine power and performance.
INDUSTRIAL APPLICATION
The present invention is particularly useful in compression ignition engines for use in over-the-road vehicles such as commercial trucks and buses.
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A high strength, lightweight camshaft for an internal combustion engine, comprising a shaft body having an axially oriented hollow interior extending a predetermined length from between a pair of spaced points, respectively, adjacent the ends of the shaft body. Plural camshaft journal bearings are spaced apart on the shaft body and include a pair of end camshaft journal bearings positioned adjacent the ends of the shaft body, respectively, with at least one inner camshaft journal bearing positioned intermediate the pair of end camshaft journal bearings. Each end camshaft journal bearing has a lubricant transfer means formed therein for receiving lubricant from an external supply and for transferring lubricant into the hollow interior of the camshaft. At least one radial hole is formed in the shaft body for providing lubricant from the hollow interior to an inner camshaft journal bearing wherein the lubricant transfer means associated with the pair of end camshaft journals provides at least two paths for lubricant to flow into the hollow interior of the camshaft for providing an even distribution of lubrication to each inner camshaft journal bearing during operation of the internal combustion engine. A supply of lubricant always remains in the camshaft to assist in lubricating the camshaft journal bearings during engine start-up.
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BACKGROUND OF THE INVENTION
The invention relates to a hydraulic lifting device on harvesting machines to lift and lower a harvesting implement. A lifting apparatus is already known wherein a reference pressure corresponding to the ground bearing load of a mower table is applied against lifting cylinders via a relief valve, wherein the reference pressure is not undercut. It is thereby possible in certain constructions, that by lowered setting of the reference pressure by the actuating valves results in a momentary lifting of the mower table, thereby increasing the risk of accident.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a lifting apparatus wherein a constant preselectable working height is setable by lowering of the mower table.
It is also an object of the present invention that the process of moving the mower table to the preselected working height is automatically ended upon reaching the working height.
Pursuant to these objects and others which will become apparent hereafter , in a first setting the lowering of the mower table is possible until it reaches a ground bearing load that is set by a reference pressure from a relief valve. In a second setting a lowering is possible without the reference pressure.
Through further embodiments of the invention additional advantages are made possible. In particular, a suspension of the lifting cylinder of the mower table is possible with the help of a second hydropneumatic reservoir. It is thereby possible to achieve a soft or a hard suspension of the lifting cylinder, depending upon the lowering process.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawing illustrates a circuit diagram of a hydraulic lifting arrangement pursuant to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In a lifting arrangement 10 for a mower table of a combine, a pressure medium is driven by a pump 11 from a tank 12 along an inlet line 13 to a 6/3-distributing slide valve 14. This valve 14 has three switch settings I, II, III and three connections a, b, c on one side and connections d, e, f on the other side. The distributing side valve 14 also has a servo-piston 15 that is attached to a cam 16. In the switch settings II and III, the cam 16 opens an electric switch 17, and in the switch setting I it closes the switch 17. Furthermore, in the switch setting II the servo-piston 15 is spring centered. From connection d of the distributing slide valve 14 a return line 18 leads to the tank 12. The connection c connects a line 19 with the return line 18, and the connection b connects a line 21 with the inlet line 13. The inlet line 13 is connected to the return line 18 by a line 22 in which a relief valve 23 is located. A line 24 leads from connection f over a hydraulic presettable check valve 25 to a stop valve 26. The check valve 25 serves to cut off the line 24 from the distributing sliding valve 14. A line 27 leads from connection e of the distributing slide valve 14 to a 2/2-solenoid valve 28 with a return spring 28'. A control line 29 branches from the line 27 shortly after the connection e and leads to the check valve 25.
The stop valve 26 has a multiple recessed housing bore 30 in which four annular T-slots are provided which define a receiver chamber 31, an inlet chamber 32, a return chamber 33 and a pressure chamber 34. Between the inlet chamber 32, in which the line 24 empties, and the return chamber 33, a piston-shaped valve element 35 is slidably led. On the end of the valve element 35 removed from the inlet chamber 32, rests a spring 36. The other end of the spring 36 rests against a stopping piece or cap 37 which closes off housing bore 30. The other end of the valve element 35 has a closing cone 35' which rests against a valve seat 39 of the return chamber 33 as a result of the force of the spring 36. A piston 38 is tightly and slidably guided in the housing bore 30 between the return chamber 33 and the pressure chamber 34, and works upon the valve element 35 against the force of the spring 36. The housing bore 30 is closed on this end by a second closing piece 40. A blind bore 41 is provided centrally in the valve element 35 extending toward the closing cone 35'. A cross-drilled hole 42 empties into the blind bore 41 at the bottom of the blind bore 41. The valve element 35 has an outer circumference in which an annular T-slot 43 is provided in the area of the cross-drilled hole 42.
A line 44 extends from the receiving chamber 31 to a 2/2-solenoid valve 45 with a return spring 45'. The solenoid valve 45 has two switch settings I and II and also has connections a, b on one side and connections c, d on the other side of the switch. From one setting of the solenoid valve 45, a line 46 connects the line 44 to connection a of the solenoid valve 45 and a line 47 connects the line 44 to the connection b. The connection d is connected with two parallel connected hydropneumatic storage tanks 49, 51 by a line 48. A line 52 runs from connection c of the solenoid valve 45 to two lifting cylinders 53, 54 each provided with a lifting piston 55, 56. The lifting cylinders 53, 54 serve to raise and lower and mower table 57. A line 58 branches before the lifting cylinders 53, 54 to a third hydropneumatic storage tank 59. This suspension line is steeper than the lines of the storage tanks 49, 51.
From the return chamber 33 of the stop valve 26 runs a first line 60 in which an adjustable relief valve 61 is provided. First line 60 runs back to the reservoir 12. A second line 62 runs from the return chamber 33 to the solenoid valve 28. A throttle 63 is located in the line 62 shortly after the return chamber 33. After the throttle 63 a line 64 branches from the line 62 to the pressure chamber 34.
The solenoid valve 28 has switch settings I and II and connections a, b on one side and connections c, d on the other side. The line 62 is connected to connection c, and the line 27 is connected to the connection b. The line 62 runs from the connection a back to the reservoir 12. A closed line 66 is connected to connection d, and is also connectable with the line 27.
An electrical lead 68 of an electric circuit runs from switch 17 to two series-connected switches 69, 70 that are associated with the lifting pistons 55, 56. The switches 69, 70 are attached to the chassis of the combine so that they are accessible from the driver compartment so that they can be selectively operated to set a desired working height of the mower table 57. With the help of, for example, terminals 71 connected to the lifting piston 56, the switches 69, 70 remain in operat:ve connection with the lifting pistons 55, 56. A lead 72 runs from the switch 70 to a magnet 73 of the solenoid valve 45, and a lead 74 runs from the switch 69 to a magnet 75 of the solenoid valve 28. A hand-actuatable multiple switch 76 with three switch settings I, II and III is connected to both leads 72 and 74. In switch setting I the lead 72 is closed, and switch setting III the lead 72 is closed and in switch setting II both leads 72 and 74 are disconnected.
When the distributing slide valve 14 finds itself in switch setting II, whereby the switch 17 is opened, the pressure medium flows from the pump 11 nearly pressureless over the inlet line 13, the distributing slide valve 14, and the return line 18 back into the reservoir 12. The check valve 25 is closed, and the solenoid valve 45 is in switch setting I because the magnet 73 is not excited. The lifting cylinders 53, 54 and the storage tanks 49, 51, 59 are closed tight from the reservoir 12 by the check valve 25. The lifting cylinders 53,54 are connected with the storage tank 59 by line 58, and are connected to the storage tanks 49, 51 by the line 52 of the solenoid valve 45, lines 46, 47 and the line 48. This results in the following: a working pressure already prevails in the lifting cylinders 53, 54, in this way the largest portion of the weight of the mower table 57 is carried by the lifting cylinders 53, 54, and thereby the mower table is relatively softly suspended over the storage tanks 49, 51 and 59.
If the distributing slide valve 14 is moved into switch setting III, the switch 17 is further opened, and the solenoid valves 28 and 45 are moved further into switch setting I. The pressure medium flows from the pump 11 over the inlet line 13, the line 21, the check valve 25, the line 24, the opened stop valve 26, the lines 44, 46, 47 of the solenoid valve 45 and the lines 48, 52 to the storage tanks 49, 51, 59 and to the lifting cylinders 53, 54. The lifting pistons 55, 56 are guided out and the mower table 57 is lifted. The lifting process is ended when the distributing slide valve 14 is returned to switch setting 2. Thereby the pump 11 is released and the check valve 25 disconnects the lifting cylinders 53, 54 from the pump 11.
When the distributing slide valve 14 is put in switch setting I, the switch 17 is closed by the cam 16. Here however the switches 69, 70 and the multiple setting switch 76 are opened and the solenoid valves 28, 45 find themselves again in their switch setting I. The working height of the mower table 57 is set manually by the driver through lowering of the mower table 57. In addition to this, the pressure medium flows from the pump 11 over the inlet line 13, the line 21, the distributing slide valve 14, the control line 29 to the check valve 25 and opens the check valve 25. The pressure medium overcomes the opening pressure of the check valve 25 and the surplus of the pressure medium flows over the line 22 and the relief valve 23 and over the return line 18 back to the reservoir 12. Now, pressure medium from the lifting cylinders 53, 54 and the storage tanks 49, 51, 59 can flow over the lines 48, 52 of the solenoid valve 45, the lines 46, 47, 44 of the stop valve 26, the line 24 and the now opened check valve 25, the distributing slide valve 14 and the line 19 to the return line 18 and back into the reservoir 12. When the desired working height is reached, the driver manually sets the distributing slide valve into the switch setting II. The check valve 25 again closes the line 24 to the distributing slide valve 14, and the selected working height of the mower table 57 remains held.
If the distributing slide valve 14 is again put in switch setting I, the switch 17 is closed. The multiple setting switch 76 is switched to the switch setting III, so that the electric lead 72 is closed. On switch 70, a desired working height of the mower table 57 is selected by sliding of the switch 70, namely the working height, that should be automatically ended by the lowering of the mower table 57. The pressure medium from pump 11, as described above, in the control line 29 and closes hydraulically the check valve 25. Pressure medium escaping from the lifting cylinders 53, 54 can again flow back to the reservoir 12 as described above.
When the working height of the lifting pistons 55, 56 as set by the switch 70 is reached, the switch 70 is closed with the help of the terminals 71. The circuit is thereby closed, so that the magnet 73 of the solenoid valve 45 is excited. The solenoid valve 45 is then set into switch setting II. Thereby the backflow of the pressure medium from the lifting cylinders 53, 54 through the lines 46, 47 to the reservoir 12, is closed. At the same time, the connection of the line 52 to the line 58 is blocked. The lifting pistons 55, 56 and therewith the the mower table 57 find themselves at the desired working height of the soil surface. At the end of the lowering movement the mower table 57 is cushioned only by the storage tank 59. The suspension through the storage tank 59 is firmer than that with the storage tanks 49, 51 together. This is necessary because the soft suspension of the mower table would allow the mower table to strike hard against the soil surface. However, a soft suspension is necessary for mowing along the soil surface. If the distributing slide valve 14 is set back into switch setting
II the selected working height of the mower table 57 is held. If the distributing slide valve 14 finds itself in switch setting I, the switch 17 is closed. The multiple setting switch 76 is now moved into switch setting I so that the electric lead 74 is connected. By a switch 69 the desired working height of the mower table 57 over the soil surface, for example, 200 mm, is set. At this working height certainly the mower table 57 lies upon the soil surface, however, the major portion of the weight of the mower table 57 is supported by the lifting cylinders 53, 54. The mower table 57 thereby lays on the soil surface with a small ground bearing force and follows all unevenness of the soil surface only with the adjusted weight. Any unevenness occuring in the soil surface is compensated for by the soft suspension with the help of the storage tanks 49, 51, 59. The ground bearing force is asserted against a reference pressure selected in the relief valve 61. The pressure medium flows from the pump again, as described above, in the control line 29 and opens the check valve 25. The pressure medium from the lifting cylinders 53, 54 and the storage tank 49, 51, 59 flows over the opened stop valve 26 in the opened check valve 25 back into the reservoir 12. If the working height selected by the switch 69 is reached, the switch 69 is closed with the help of the terminal 71, and the electric leads 68 and 74 are connected. The magnet 75 of the solenoid valve 28 is excited so that the solenoid valve is switched into switch setting II. A pressure medium flowing from the pump 11 can now flow over the control line 29 to the check valve 25 as well as over the line 27 into the line 62. From there the pressure medium reaches over the throttle 63, the return chamber 33 and the line 60 to the pressure relief valve 61. So long as the reference pressure set in the pressure relief valve 61 is higher than the pressure of the pressure medium in the line 60, no pressure medium flows further back into the reservoir 12. The pressure medium flows from the line 62 over the line 64 into the pressure chamber 34, so that the pressure let off from the throttle 63 is able to influence the piston 38. So long as pressure medium still flows out of the lifting cylinders 53, 54 into the reservoir 12, the bearing pressure on the valve element 35 is higher than the pressure working on the piston 38 which is fixed from the reference pressure of the pressure relief valve 61.
If the mower table 57 now lays on the soil surface and the pressure in the lifting cylinders 53, 54 has lowered to the reference pressure of the pressure relief valve 61, the piston 38 and with it the valve element 35 is lifted from the valve seat 39 by the working pressure in the pressure chamber 34. The inlet chamber 32 is thereby closed, so that no more pressure medium can flow from the lifting cylinders 53, 54 and from the storage tanks 49, 51, 59 to the reservoir 12, notwithstanding the opened check valve 25. At the same time however, the return chamber 33 of the stop valve 26 is connected with the storage tanks 49, 51, 59 and the lifting cylinders 53,54 by way of the blind bore 41, the cross-drilled hole 42 and the now opened valve seat 39. The reference pressure of the pressure relief valve 61 prevails in the return chamber 33, and therewith works also the reference pressure in the lifting cylinders 53, 54 in the storage tanks 49, 51, 59. A further lowering of the working pressure in the lifting cylinders 53, 54 under the reference pressure is prevented. The reference pressure is thereby selected to be so large that the largest portion of the weight of the mower table 57 is braced by the lifting cylinders 53, 54 and only a small residual weight is placed against the earth. This remaining ground bearing force is also dependent upon the difference between the weight of the mower table 57 and the reference pressure on the pressure relief valve 61.
If now the distributing slide valve 14 is again set in switch setting II the check valve 25 is closed. No more pressure medium flows in line 27 and in line 62 so that the pressure on the piston 38 is reduced. The connection of the receiver chamber 31 to the inlet chamber 32 is once again opened, due to the valve element 35 sliding onto the valve seat 39. With the help of the cam 16 the switch 17 is opened so that the magnet 75 of the solenoid valve 28 is no longer excited. The solenoid valve 28 returns thereby to its switched setting I. The pressure adjust the number of lifting cylinders 53, 54, which now corresponds with the reference pressure, is maintained by way of the storage tanks 49, 51, 59. The ground bearing force of the mower table 57 only varies within the suspension range of the storage tanks 49, 51, 59. Since these are relatively soft, namely having a flat characteristic, the variations are lowered. The mower table 57 can thereby slide along the soil surface without the need for additional corrections from the driver.
Without changing the function of the invention, it is also possible, that the stop valve 26 can be constructed as a mechanical or electromagnetically actuated 2/2-distributing slide valve. The magnet of the electromagnetically actuated valve can thereby be connected to the line 74.
While the invention has been illustrated and described as embodied in a hydraulic lifting apparatus for a harvester, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.
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A hydraulic lifting apparatus for harvesting machines, the apparatus having a plurality of lifting cylinders connected to the undercarriage of the harvesting machine which support a mower table so that it rests on the ground with a minimal resting weight, and also having energy storing tanks to provide different suspension of the mower table. To accomplish this a hydraulically actuatable stop valve is located in a first circuit of working lines running between a distributing slide valve and the lifting cylinders. This stop valve is actuated by a control pressure which is branched from a second circuit of working lines. The second circuit of working lines runs from the distributing slide valve over a pressure relief valve to a reservoir, and is able to be disconnected by a solenoid valve. The stop valve has a valve element with a series of bores through which the pressure set by the pressure relief valve passes through the blocked first circuit of working lines into the lifting cylinders. Thereby the mower table automatically lowers with a preselected ground bearing force or selectively without the ground bearing force.
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This application is a 371 of PCT/DE04/02122 filed on Sep. 16, 2004.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a method for measuring the voltage at a point in a power distribution network by means of a measuring circuit, which has a voltage sensor, which is coupled to a current-carrying conductor of the network, and a further-processing arrangement, which is connected to the voltage sensor, and outputs a measured voltage value as the output signal at its output, and to an apparatus for carrying out this method.
In power distribution networks, preferably in the voltage range of 6-20 kV, at present devices are still predominantly used for protection and control purposes which represent directionally independent overcurrent protection. This is sufficient in networks having a central supply and in which the current direction is predetermined. In the case of a decentralized supply, however, it is also necessary, for the response of protective devices, for the direction of a current to also be detected, in addition to the level of the current. This can be determined by additional voltage measurements in the network. For this purpose, inductive voltage transformers are generally used today as the voltage sensors. They make it possible to measure the voltage accurately, but represent a considerable cost factor, in particular if they are installed retrospectively in existing networks.
The German laid-open specification DE 23 25 449 A1 describes the use of a capacitive voltage transformer as a voltage sensor for the purpose of measuring the voltage in high-voltage switchgear assemblies, said voltage transformer being formed from a current-carrying conductor of the high-voltage network and an electrode embedded in a post insulator of the conductor. Such capacitive voltage transformers are generally used today, however, merely for establishing the presence of a voltage having a specific minimum level on a line of a power distribution network the displacement current of a high-voltage coupling capacitor, since the measurement result obtained is sometimes relatively inaccurate, with the result that it can only be used to establish the presence of the voltage but not to determine its precise value.
SUMMARY OF THE INVENTION
The object of the present invention is to specify a method and an apparatus of the abovementioned type, by means of which accurate voltage measurement can be carried out irrespective of the type of voltage sensor.
In terms of the method, this object is achieved according to the invention by the fact that, in a method of the mentioned type, the output signal from the measuring circuit is corrected so as to achieve a correct measured value by means of a correction element having a transfer function which is inverse to the transfer function of the measuring circuit. As a result of the fact that the output signal from the measuring circuit is corrected so as to achieve a correct measured value by means of a correction element having a transfer function which is inverse to the transfer function of the measuring circuit, it is possible, using comparatively simple means, for sufficiently accurate voltage measurement to be carried out irrespective of the type of voltage sensor.
The method according to the invention can advantageously provide for a capacitor device to be used as the voltage sensor of the measuring circuit. The use of a capacitor device—i.e. a capacitive voltage transformer—as the voltage sensor represents a comparatively cost-effective possibility for voltage measurement.
In this context, it is also regarded as advantageous if a coupling capacitor, formed from the current-carrying conductor of the network and an electrode which is DC-isolated from said current-carrying conductor, is used as the capacitor device. Such capacitor devices have a comparatively simple design; in addition, capacitor devices of this type are already often provided, for example, in high-voltage bushings of switchgear cells.
As an alternative, however, it is also advantageously possible to provide for an inductive voltage transformer, which is connected on the primary side to the current-carrying conductor, to be used as the voltage sensor. This is regarded as being particularly advantageous because such an inductive voltage transformer generally makes very accurate voltage measurement possible. Since, however, the measuring circuit can also have a transfer function which slightly falsifies the measured voltage value when an inductive voltage transformer is used, even more accurate measured voltage values can be achieved in this case too when using the correction by means of the correction element in accordance with the method according to the invention.
In this case, however, it is also regarded as advantageous if a correction element is used which can optionally be bypassed via a switch. In this manner, the correction element can easily be bypassed if the measured voltage values achieved using the inductive voltage transformer are sufficiently accurate; in such a case no correction of the measured voltage values therefore takes place.
Depending on whether the output signal from the measuring circuit is analog or digital, an analog or digital filter having a transfer function which is inverse to the transfer function of the measuring circuit can be used as the correction element. The analog filter expediently simulates a transfer function having a PID characteristic.
When using a digital filter, a temporally discrete transfer function is suitable as the inverse transfer function. This can be generated in a manner known per se by means of a bilinear transformation.
In this context, it is also regarded as advantageous if, in the case of the digital filter, the coefficients of the temporally discrete transfer function can be altered. In this case, the transfer function of the correction element can be matched in a particularly simple manner to transfer functions of the measuring circuit brought about by different voltage sensors.
One further advantageous development of the method according to the invention also provides for a further-processing arrangement to be used which has a DC isolating element in its input region. The further-processing arrangement and the correction element can thus be DC-isolated from the high-voltage side without any problems.
In terms of the apparatus, the object on which the invention is based is achieved by a measuring apparatus for measuring the voltage at a point in a power distribution network by means of a measuring circuit, which has a voltage sensor, which is coupled to a current-carrying conductor of the network, and a further-processing arrangement, which is connected to the voltage sensor, and outputs a measured voltage value as the output signal at its output, a correction element being connected to the measuring circuit on the output side in accordance with the invention so as to achieve a correct measured value from the output signal from the measuring circuit, said correction element having a transfer function which is inverse to the transfer function of the measuring circuit. Owing to the use of a correction element having a transfer function which is inverse to the transfer function of the measuring circuit, it is possible to achieve accurate measured voltage values with such a measuring apparatus using any desired measuring sensors.
For reasons of cost, provision can advantageously be made for the voltage sensor to be a capacitor device. In accordance with one preferred embodiment, such a capacitor device may also be a coupling capacitor formed from the current-carrying conductor of the network and an electrode which is DC-isolated from said current-carrying conductor. An electrode having this design may preferably be a so-called ring electrode.
As an alternative, however, provision may also be made for the voltage sensor to be an inductive voltage transformer, which is connected on the primary side to the current-carrying conductor.
Since such an inductive voltage transformer often already produces measured voltage values of a very high quality, in this context provision may also be made for it to be possible for the correction element to be optionally bypassed via a switch.
However, even in the case of an inductive voltage transformer, the quality of the measured voltage values can often be increased further still by the use, according to the invention, of a correction element having an inverse transfer function, with the result that it is also worthwhile in this case to use the correction element, which in this case is therefore not bypassed.
In other words, a measuring apparatus according to the invention has, for example, an input terminal for the optional connection to any desired voltage sensors, for example to the electrode of the coupling capacitor or to the secondary winding of an inductive voltage transformer, which is connected on the primary side to the current-carrying conductor. As a result, it is in this case possible to connect the measuring apparatus to the corresponding voltage sensor irrespective of whether a coupling capacitor or an inductive voltage transformer has already been installed at the measurement point in the network. The measuring apparatus is then provided with a switch for optionally switching the correction element which simulates the inverse transfer function on or off in order to switch the correction element on in the event of a connection to the coupling capacitor and to switch the correction element off, if required, in the event of a connection to the voltage transformer. Even in the case of the inductive voltage transformer, in this case the correction element could remain switched on, in which case the inverse transfer function of said correction element would have to be correspondingly altered. It would be possible for this to be carried out in a simple manner, in particular in the case of a digital filter having a temporally discrete transfer function as the correction element, by adjusting the coefficients.
Depending on whether the output signal from the measuring circuit is an analog or a digital output signal, an analog filter having a PID characteristic or a digital filter can correspondingly be used.
One advantageous development of the measuring apparatus according to the invention provides for the further-processing arrangement to have a DC isolating element in its input region. It is thus possible to DC-isolate the high-voltage part of the measuring apparatus from the low-voltage part in a simple manner. The DC isolating element can preferably be an inductive current transformer.
In accordance with one further advantageous development of the measuring apparatus according to the invention, the voltage sensor is connected on the output side to a series circuit comprising a resistor having a high resistance value and the primary winding of the inductive current transformer. The input voltage of the further-processing arrangement is converted to a comparatively low current via the resistor having a high resistance value such that the inductive current transformer can be designed to be comparatively small and thus inexpensive.
One further advantageous development of the measuring apparatus according to the invention also provides for the secondary winding of the current transformer to be loaded by a negative feedback operational amplifier with an internal resistance of 0 ohm. In turn, a current/voltage conversion takes place using the operational amplifier, in which case the range of the level of the resulting voltage can be adjusted by the negative feedback of the operational amplifier, for example via a resistor arranged in the negative feedback path.
In addition, one advantageous embodiment of the measuring apparatus according to the invention is regarded as the fact that the measuring circuit has an analog-to-digital converter on the output side in order to generate digital output signals from the measurement arrangement.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE of the drawing is a schematic diagram of a measuring apparatus according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention will be explained in more detail below with reference to an exemplary embodiment illustrated in the FIGURE. The FIGURE shows the circuit diagram of a measuring apparatus MV for voltage measurement using a digital filter as the correction element KG in order to correct the measured voltage values.
A current conductor 1 of a power distribution network forms an electrode of a capacitive voltage transformer as the voltage sensor SG in the form of a high-voltage coupling capacitor 2 . The other electrode of the coupling capacitor 2 , which is preferably passed around the current conductor 1 in annular fashion such that it is DC-isolated from said current conductor 1 , is connected to an input terminal 3 of a further-processing arrangement WA of the measuring apparatus MV. In a similar manner, other forms of capacitive voltage transformer are also possible as the voltage sensor SG, however. As illustrated in the FIGURE, the capacitive voltage transformer may optionally be a capacitive divider, whose low-voltage capacitor is represented by dashed lines in the FIGURE. An embodiment in the form of a capacitive divider is not absolutely necessary, however. Instead, as is indicated by the further dashed line, the secondary winding of an inductive voltage transformer 4 , which is connected on the primary side to the current conductor 1 , can also be connected to the input terminal 3 of the further-processing arrangement WA. As is indicated in the FIGURE by the curved bracket, the voltage sensor SG and the further-processing arrangement WA together form a so-called measuring circuit MS.
The text which follows will consider the case in which the coupling capacitor 2 as the voltage sensor SG is connected to the input terminal 3 of the further-processing arrangement WA. A series resistor 5 (Rv), which generally has a high resistance value and is arranged downstream of the input terminal 3 , carries out a voltage/current conversion of the voltage, which has been tapped off capacitively at the electrode, which is DC-isolated from the current conductor 1 , of the coupling capacitor 2 , to a displacement current. In addition, the series resistor 5 forms, with the capacitance of the coupling capacitor 2 , a high-pass filter and therefore improves the input-side EMC (electromagnetic compatibility) performance of the measuring apparatus MV.
A DC isolating element, which is connected on the primary side in series with the series resistor 5 and is in the form of an inductive current transformer 6 , on the one hand serves the purpose of potential isolation and, on the other hand, serves the purpose of reducing the coupling capacitance with respect to the high-voltage conductor and thus brings about further EMC shielding. Owing to the displacement current which is low as a result of the dimensions of the series resistor 5 , the inductive current transformer 6 can be designed to be relatively small.
An operational amplifier 7 having a feedback resistor 8 (Rm) is connected to the secondary side of the inductive current transformer 6 . The operational amplifier 7 acts as an active load for the inductive current transformer 6 with an internal resistance of 0 ohm. At the same time, the operational amplifier 7 takes on the function of current/voltage conversion and converts the current produced by the inductive current transformer 6 to a voltage. The ratio between the output voltage and the input current of the operational amplifier 7 is determined by the value Rm for the feedback resistor 8 . This value can be switched over by means of a link or an analog switch, as indicated in the FIGURE, in order to be able to match the driving of the current transformer 6 , which driving is dependent on the coupling capacitor 2 or the voltage transformer 3 , to the measurement range of an analog-to-digital converter 9 downstream of the operational amplifier 7 .
Said analog-to-digital converter 9 converts its input voltage to a digital sample sequence.
If the input terminal 3 of the further-processing arrangement WA is connected to the inductive voltage transformer 4 , the transfer performance of the measuring circuit MS formed from the voltage sensor SG (i.e. in this case the inductive voltage transformer 4 ) and the further-processing arrangement WA is independent of the frequency in the relevant frequency range (50 or 60 Hz).
In contrast, in the event of a connection to the coupling capacitor 2 , the following transfer function for the measuring circuit MS to the analog-to-digital converter 9 results:
U A U Prim = j ω C D · R m 1 + j ω C D · R v
where U A is the voltage at the output of the operational amplifier 7 , U Prim is the voltage of the current conductor 1 , and C D is the capacitance of the coupling capacitor 2 . If the value for U A resulting using this transfer function is left unchanged, a measured voltage value is obtained which is completely unsuitable for accurate voltage measurement. The transfer function of the entire measuring apparatus MV (comprising the voltage sensor SG, the further-processing arrangement WA and the correction element KG) therefore needs to be corrected by a downstream correction element KG by means of a transfer function which is inverse to the transfer function of the measuring circuit MS. This correcting inverse transfer function of the correction element KG should be formed in accordance with the following equation:
G
corr
=
1
+
j
ω
C
D
·
R
v
1
+
j
ω
T
K
The resultant transfer function of the entire measuring apparatus MV in turn represents a high-pass filter, but with a new cut-off frequency 1/(2*pi*T K ). The time constant T K can in this case be selected such that the cut-off frequency is below the frequency range to be detected for the measured voltage value, with the result that the transfer function of the entire measuring apparatus MV is linear in this frequency range. It is particularly advantageous if T K is equal to the time constant of the current transformer used for detecting the current signals, which are likewise measured at the same time as the voltage signal.
If, as shown in the FIGURE, a digital filter 10 is used to correct the transfer function of the measuring circuit MS, the correcting transfer function G corr can previously be transformed into a temporally discrete transfer function G(z −1 ). This takes place with the aid of the bilinear transformation
ⅇ
-
j
ω
T
A
=
2
T
A
·
z
+
1
z
-
1
.
The right-hand side of this equation is the series expansion, terminated after the first element, of the function e −jω·T . This gives:
G ( z - 1 ) = a 1 z - 1 + a 0 1 + b 1 z - 1 ,
where z −1 is the delay of a sampled value by a sampling interval; a 0 , a 1 and b 1 are coefficients of the temporally discrete transfer function. This temporally discrete transfer function G(z −1 ) is implemented by the digital filter 10 illustrated in the FIGURE. This in turn has a final amplification at the frequency 0, with the result that the numerical stability of the apparatus is ensured even in the case of an offset of the analog-to-digital converter 9 .
A switch 11 is used to connect the output of the analog-to-digital converter 9 to the measured value output 12 of the measuring apparatus MV either directly or via the digital filter 10 . The direct connection can be selected if the inductive voltage transformer 4 as the voltage sensor SG is connected to the input terminal 3 of the further-processing arrangement WA, and the connection via the digital filter 10 is selected if the coupling capacitor 2 as the voltage sensor SG is connected to the input terminal 3 . The switch 11 could, however, also be dispensed with, with the result that, in both cases, the digital filter 10 is included since an improvement in the quality of the measured voltage values can be achieved owing to the shift in the cut-off frequency of the transfer function of the entire measuring apparatus MV even in the case in which the inductive voltage transformer 4 is used. However, the coefficients of the digital filter 10 can in each case be adjusted differently for the connection to the inductive voltage transformer 4 , on the one hand, and to the coupling capacitor 2 , on the other hand.
Correspondingly, a measuring apparatus can also be implemented using analog voltage signals, in which case an analog filter would be used in place of the digital filter, and the analog-to-digital converter would be dispensed with.
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A method measures a voltage at a point of a current distribution network via a measuring circuit. The measuring circuit contains a voltage transmitter which is coupled to a current-conducting conductor of the network, and a further processing configuration which is connected to the voltage transmitter and which outputs a voltage measuring value as an output signal at the output thereof. The output signal of the measuring circuit is corrected by a correction element that has a transfer function that is inverse to the transfer function of the measuring circuit in order to obtain precise voltage measuring values that are independent from the type of the selected voltage transmitter. A measuring device is provided for carrying out the method.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from German Patent Application No. 102 29 172.1, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a card top bar for a carding machine, having a carrying member and a releasable clothing portion.
[0003] In a known card top bar there are provided two end headpieces (card top heads), each of which slides on a slideway, the end head-pieces comprising at least one sliding region, which is in contact with the slideway, and at least one fixing region, which is in engagement with the card top bar and which at the same time holds the sliding region. In that known card top bar, the end head-pieces (card top heads) are associated with the carrying member.
SUMMARY OF THE INVENTION
[0004] It is an aim of the invention to improve the known card top bar still further.
[0005] The invention provides a card top bar for a carding machine, having a carrying member and a releasable clothing portion, the clothing portion having clothing, a carrier for the clothing, and two card top heads, the card top heads comprising at least one sliding region arranged for sliding, in use, on a slideway, wherein the card top heads and the carrier for the clothing are in engagement with one another and form a structural unit.
[0006] The fact that the card top heads are in engagement with the carrier for the clothing makes it possible for the clothing portion, including the card top heads, to be manufactured as a separate component. In the process, it is made possible for a constant setting to be obtained for the important spacing between the sliding surface of the card top heads and the free ends (tips) of the clothing. Manufacturing tolerances in the carrying member, which is made, for example, from extruded aluminium, are substantially prevented from having an adverse effect on that spacing. A further advantage is that, when the clothing has become worn, the complete clothing portion (clothing strip, holding device and card top heads) can be removed and thrown away. It is especially advantageous that replacement of the clothing portion is carried out by simple means in the spinning room, it being possible for the carrying members to be re-used without modification. Precise setting of the card top heads relative to the clothing tips and, accordingly, of the important spacing between the clothing tips and the cylinder clothing (carding nip) is made possible by means of the measures according to the invention.
[0007] The carrier may be of one-piece construction. The carrier may instead consist of a carrying element for the clothing and a compensating layer which may be connected to one another. The compensating layer may be arranged between the carrier and the carrying member. The card top heads may be in engagement, preferably non-releasably, with the carrier, for example with a compensating layer thereof, for example, directly or by way of an auxiliary carrier.
[0008] The fixing region for the card top heads may be arranged in the compensating layer, for example with the sliding region extending outwardly beyond the carrier. Each card top head may have two elements, for example, pins of hardened steel or the like, the sliding surface of which may be ground, fine-ground and/or polished. The card top heads may be fixed in the respective end face of the carrier. Advantageously, the lower boundary of the card top heads is spaced from the free clothing tips. The carrying member and the clothing portion may form at least two composite components. The clothing portion advantageously comprises the carrier, the clothing and the card top heads. The carrying member and the clothing portion are advantageously connected to one another by releasable fixing means, for example, clips, clamps or the like. Fixing means, for example, resilient snap-fit elements, may be attached to the carrying member or to the clothing portion.
[0009] The card top heads maybe connected to the carrier by adhesive action or the like. Advantageously, at least one continuous rod or the like, advantageously of a wear-resistant material, is provided, which extends over the width of the card top bar. The rod or the like may be accommodated within the carrier. The ends of the rod or the like may extend out beyond the carrier on both sides, in the form of card top heads.
[0010] Where a compensating layer is present, that may be of plastics material or the like, for example of a synthetic resin such as epoxy resin, or of polyester or the like. The plastics material, synthetic resin or the like may be curable, and/or may be pourable. It may be, for example, an adhesive. The plastics material, synthetic resin or the like advantageously adheres more strongly to the clothing carrier than at the bottom surface of the carrying member. The compensating layer may be a rigid foam. Advantageously, an adhesive layer may be provided between the compensating layer and the bottom surface of the card top bar. A compensating step may be provided in the bottom surface of the carrying member.
[0011] The card top bar and the card top clothing are associated with the same reference plane. The reference plane may be a flat counterpart surface for the tip of the card top clothing, for example a plate or the like. The card top carrying member may be an extruded member of a light metal, for example aluminium, which is advantageously hollow and may be cut to length, for example by sawing. Advantageously, the cut-to-length carrying member can be straightened. Two end head-pieces (card top heads) may be associated with the carrier. Advantageously, a carrying element for the card top clothing, for example of textile material, and a compensating layer are arranged at a recess in the bottom surface of the carrying member. Advantageously, a spacing between the sliding surfaces at the card top heads on the outer surface of the slideway and the envelope curve of the card top clothing tips is even.
[0012] The card top heads may lie on a reference plane, for example a flat metal member or the like. The reference plane may be a magnetic plate. The plate and the reference plane may be attached to a common holding element. The reference plane and a further reference plane coinciding with the clothing tips may be orientated parallel to one another. The spacing between the reference planes may be adjustable.
[0013] For manufacture, the clothing tips are set down on the further reference plane and the card top heads are set down on the reference plane, and an intermediate layer is applied between the carrying member and the clothing strip. The intermediate layer may be applied by melting, for example, after warming or otherwise heating. The underside of the carrying member may be structured, for example having recesses, protrusion, holes or the like. The carrier may have lateral recesses, grooves or the like for engagement of the fixing elements. Fixing elements may be present on the carrying members for engagement with the bottom surface of the carrier. The carrying member may have lateral shoulders, recesses or the like for engagement of fixing elements present on the carrier. For fixing the clothing portion, fixing means for example resilient snap-in elements may be attached to the carrier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1 is a diagrammatic side view of a carding machine having the apparatus according to the invention;
[0015] [0015]FIG. 2 is a diagrammatic side view of clothed card top bars, portions of a slideway and flexible bend, and the spacing between the card top bar clothing and cylinder clothing;
[0016] [0016]FIG. 3 a is a sectional side view of the rear part and carrying member of the card top bar;
[0017] [0017]FIG. 3 b is a a side view of a carrier;
[0018] [0018]FIG. 3 c is a side view of a clothing strip;
[0019] [0019]FIG. 3 d shows the card top bar having the apparatus according to the invention, in an assembled state;
[0020] [0020]FIGS. 4 a, 4 b show a further arrangement of the card top bar and holding element, having a click and snap-in connection;
[0021] [0021]FIG. 5 shows, in a side view and partly in section, an arrangement according to the invention, having a device for alignment of the card top bar for application of a compensating layer;
[0022] [0022]FIG. 6 is a detailed view of a part of the arrangement according to FIG. 5; and
[0023] FIGS. 7 to 10 show further embodiments of the apparatus according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] With reference to FIG. 1 a carding machine, for example a Trützschler DK 903 (trade mark) high-performance carding machine, having a feed roller 1 , feed table 2 , lickers-in 3 a, 3 b, 3 c, cylinder 4 , doffer 5 , stripper roller 6 , nip rollers 7 , 8 , web-collecting element 9 , web funnel 10 , draw-off rollers 11 , 12 , revolving card top 13 having clothed card top bars 14 , can 15 and can coiler 16 . Curved arrows indicate the directions of rotation of the rollers. Reference letter A denotes the work direction. Stationary carding elements 33 and 34 are arranged opposite the cylinder clothing 4 a.
[0025] In accordance with FIG. 2, on each side of the carding machine, a flexible bend 17 having several adjustment screws is fixed laterally to the machine frame. The flexible bend 17 has a convex outer surface 17 a and an underside 17 b. On top of the flexible bend 17 there is a slideway 20 , for example made of low-friction plastics material, which has a convex outer surface 20 a and a concave inner surface 20 b. The concave inner surface 20 b rests on top of the convex outer surface 17 a and is able to slide thereon in the direction of arrows B, C. Each card top bar, which may be constructed, for example, in accordance with EP 0 567 747 A1, consists of a rear part 14 a and a carrying member 14 b. The carrying member 14 b has a bottom surface 14 c, two lateral surfaces 14 d, 14 e and two upper surfaces 14 f, 14 g (see FIG. 3 a ). Each card top bar 14 has, at each of its two ends, a card top head 14 ′, 14 ″ (cf. FIG. 5), each of which comprises two steel pins 14 1 , 14 2 and 14 3 , 14 4 , respectively, a portion of which in the axial direction is fixed in a compensating layer 24 . Those portions of the steel pins 14 1 , 14 2 (see FIG. 9) that extend out beyond the end faces of the carrying member 14 b slide on the convex outer surface 20 a of the slideway 20 in the direction of the arrow D. The clothing strip 18 is attached to the underside of the carrying member 14 b. Reference numeral 21 denotes the circle of tips of the card top clothings 19 . The cylinder 4 has on its circumference a cylinder clothing 4 a, for example a sawtooth clothing. Reference numeral 22 denotes the circle of the tips of the cylinder clothing 4 a. The spacing between the circle of tips 21 and the circle of tips 22 is denoted by reference letter a and is, for example, {fraction (3/1000)}″. The spacing between the convex outer surface 20 a and the circle of tips 22 is denoted by reference letter b. The radius of the convex outer surface 20 a is denoted by reference letter r 1 and the radius of the circle of tips 22 is denoted by reference letter r 2 . The radii r 1 and r 2 intersect at the centre point M of the cylinder 4 .
[0026] In accordance with FIG. 3 a, the card top bar 14 , which is extruded from aluminium, is composed of the rear part 14 a and the carrying member 14 b. The carrier 26 according to FIG. 3 b, which is extruded from aluminium, is composed of a holding element 26 a and two fixing elements 26 b and 26 c. The free end regions 26 b 1 and 26 c 2 of the holding elements 26 b and 26 c are bent at right angles in different directions. They may, in each case, also be bent at an acute angle. The carrier 26 is made of one piece from one material. The fixing elements 26 b and 26 c may also be attached to the holding element 26 a, for example by laser welding. The fixing elements 26 b, 26 c and the holding element 26 a may also be made from different materials. The regions 26 a 2 and 26 a 3 are used for additional holding of the carrying element 23 for the clothing strip 18 (see FIG. 3 c ). In accordance with FIG. 3 c, the clothing strip 18 consists of clothing tips 19 (small wire hooks) and a carrying element 23 made from a textile material. Reference letter f denotes the thickness of the carrying element 23 . At one of their ends, the small wire hooks 19 are fixed in the carrying element 23 , through the surface 23 ′. At the other end, the small wire hooks 19 , that is to say the clothing tips, are free.
[0027] [0027]FIG. 3 d shows the card top bar 14 according to FIGS. 3 a to 3 c in the assembled state. The clothing strip 18 is fixed to one face 26 2 (the inner face) of the carrier 26 . The other face 26 1 (the outer face) of the carrier 26 lies against the carrying member 14 b. The end regions 26 b 2 and 26 c 2 of the fixing elements 26 b and 26 c, respectively, press against the upper surfaces 14 f and 14 g, respectively, of the carrying member 14 b, as a result of which the carrier 26 , together with the clothing strip 18 , is fixed to the card top bar 14 . Arranged between the inner face 26 2 of the carrier 26 and the carrying element 23 is an intermediate layer 24 , for example made from cured synthetic resin or the like which may act as a compensating layer. The compensating layer 24 is able to compensate for disparate spacings between the card top bar 14 , namely the bottom surface 14 c, and the card top clothing 19 , namely the envelope contour of the free tips. The fixing region for the steel pins 14 1 , 14 2 forming the card top head 14 ′ is arranged in the compensating layer 24 (see FIG. 6). The sliding region of the steel pins 14 1 , 14 2 extends freely outwards, beyond the end face of the compensating layer 24 (see FIGS. 5 and 6). In that manner, the card top heads 14 ′, 14 ″ and the holding device—which, in accordance with FIG. 3 d, is composed of the holding element 26 and the compensating layer 24 —for the clothing strip 18 are in engagement with one another and together form a structural unit. The structural unit consisting of holding element 26 , compensating layer 24 , clothing strip 18 and card top heads 14 1 , 14 2 is prefabricated separately. A further advantage is that the structural unit can be mounted on the carrying member 14 b, and removed from the carrying member 14 b, by simple means both in the manufacturing factory and at the user's premises, that is to say in the spinning room itself. The structural unit can be supplied to the user in the form of a prefabricated replacement part.
[0028] [0028]FIG. 5 shows an arrangement suitable for manufacturing a card top bar according to the invention. Arranged in a fixed position on a flat plate 25 , between the card top pins 14 1 , 14 2 and the plate 25 , is a parallelepipedal supporting element 27 a having parallel and flat surfaces and, between the card top pins 14 3 , 14 4 and the plate 25 , a further parallelepipedal supporting element 27 b of the same height h. Using this apparatus and further lateral fillet elements (not shown) or the like (for example, displaceable boundary surfaces for the compensating layer 24 and/or the carrying element 23 ), it is possible to position the clothing tips 19 of the clothing strip 18 on the plate 25 and the pins 14 1 , 14 2 , 14 3 , 14 4 on the supporting elements 27 a, 27 b. The compensating layer 24 is then introduced between the carrier 26 and the carrying element 23 . That may be accomplished by, for example, pouring it in, injecting it, spreading it in, laying it in or the like. The compensating layer 24 , for example of paste-like consistency, becomes distributed in the intermediate space, filling it in compensating manner. In accordance with FIG. 6, there is provided a static carrier element 14 *, which can, for example, in accordance with FIG. 3 a, be constructed in the form of a T-carrier or the like. The receiving portion for the card top pins 14 2 may consist of, for example, a poured compound/adhesive, construction foam or the like. The height h always has the same dimension in the case of all card top bars, thereby eliminating dimensional tolerance. The fixing region of the card top pin 14 2 is arranged in the compensating layer 24 , and the free end thereof—the region sliding on the slideway 20 a of the sliding bend 20 (see FIG. 2)—is located outside the compensating layer 24 .
[0029] In the embodiment of FIG. 7, separate spring clips 29 a, 29 b are provided, by means of which the structural unit composed of compensating layer 24 , clothing strip 18 (consisting of clothing 19 and carrier 23 ) and card top pins 14 1 , 14 2 ( 14 3 and 14 4 are not shown) is releasably fixed to the carrying member 14 b of the card top bar 14 .
[0030] [0030]FIG. 8 shows an embodiment wherein resilient clips 14 h, 14 i are integrally formed on the carrying member 14 b, for example during extrusion. As a result, the clips 14 h, 14 i are integrated into the card top bar 14 . The compensating layer 24 has longitudinal grooves 30 a, 30 b on its sides, extending in the width-wise direction, in which the bent-over free ends of the resilient clips 14 h, 14 i releasably engage.
[0031] [0031]FIG. 9 shows an embodiment, wherein resilient clips 26 d, 26 e are integrally formed on the carrier 26 , for example during extrusion. As a result, the clips 26 d, 26 e are integrated into the carrier 26 . The clips have, on their free ends, engagement portions, which are in releasable engagement with corresponding engagement surfaces on the carrying member 14 b. The parts in engagement with one another may be bent over, for example at an acute or obtuse angle.
[0032] In the embodiment of FIG. 10, the compensating layer 24 is enclosed by an approximately U-shaped tension bar 31 made from metal, above which the rear part 14 a of the card top bar 14 is formed from rigid foam or the like. Provided at the top of the rear part 14 a is an approximately U-shaped compression bar 32 made from metal. The compression bar 32 and tension bar 31 equalise forces and stabilise the rear part 14 a. The statically supporting part is also integrated into the wearing component. A sandwich construction makes that technically possible. This solution precludes the need for on-site assembly.
[0033] The apparatus according to the invention substantially reduces the flatness tolerance and dimensional tolerance, measured over the clothing surface, within a card top set consisting of several card top bars 14 . A further important advantage is that, when clothings are replaced at the customer's premises, the installation work is reduced. As a result of the invention, the interface between pins (and clothing) is shifted. The pins are an integral part of the wearing portion, namely the clothing. As especially FIGS. 3 d, 5 , 6 and 7 to 10 show, the clothing 19 , material 23 , tolerance-compensating layer 24 and card top pins 14 1 , 14 2 form one component. It is accordingly possible for dimension h always to be kept the same and for the customer to be provided with a component in which precision is already in-built.
[0034] FIGS. 7 to 10 show, by way of example, secure and simple mounting of this unit (component) on the static carrier. It is envisaged, however, that any convenient form of mounting may be used for that purpose.
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A card top bar for a carding machine, has a carrying member and a releasable clothing portion in which card top bar there are provided two card top heads, each of which slides on a slideway, the card top heads comprise at least one sliding region, which is in contact with the slideway, and at least one fixing region, which is in engagement with the rest of the card top bar and which at the same time holds the sliding region.
In order to improve the card top bar, the card top heads are in engagement with the carrier for the clothing.
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BACKGROUND
[0001] 1. Field of Invention
[0002] The present disclosure relates in general to a wellhead assembly having a seal between coaxial members, where wickers are formed on a surface of the seal.
[0003] 2. Description of Prior Art
[0004] Seals are typically inserted between inner and outer wellhead tubular members to contain internal well pressure. The inner wellhead member is generally a hanger for supporting either casing or tubing that extends into the well. Outer wellhead members are usually one of a wellhead housing, or can be a casing hanger when the inner member is a tubing hanger. A variety of seals located between the inner and outer wellhead members are known. Examples of known seals are elastomeric, metal, and combinations thereof and elastomeric rings. The seals may be set by a running tool, or they may be set in response to the weight of the string of casing or tubing. One type of metal-to-metal seal has seal body with inner and outer walls separated by a cylindrical slot, forming a “U” shape. An energizing ring is pushed into the slot in the seal to deform the inner and outer walls apart into sealing engagement with the inner and outer wellhead members, which may have wickers formed thereon. The energizing ring is typically a solid member with a lower end having a wedge-shaped cross section. The deformation of the seal's inner and outer walls exceeds the yield strength of the material of the seal ring, making the deformation permanent.
[0005] Thermal growth between the casing or tubing and the wellhead may occur. The well fluid flowing upward through the tubing, and annulus fluids, heats the string of tubing, and to a lesser degree the surrounding casing. The temperature increase may cause the tubing hanger and/or casing hanger to move axially a slight amount relative to the outer wellhead member. During the heat up transient, annulus pressure may build up as the fluids comprising the volume below the seal try to expand. This annulus pressure build-up and thermal expansion of the casing and/or tubing string combine to exert a large upward axial force, often referred to as a “lockdown force”, against the annulus seal. If this force exceeds the retention capacity of the seal, the pressure controlling barrier between the inner and outer wellhead tubular members can be compromised. Seal leakage can also occur due to a collection of debris on the wickers that interferes with energizing the seal and introduces a leak path across the wickers.
[0006] A large axial load between the seal and its mating surfaces due to thermal transients may also cause the seal to leak. One approach to preventing this type of movement is through the use of lockdown C-rings on the seal. The C-rings engage the outer tubular member and/or the hanger when the seal is set, locking the seal to the hanger, as well as the hanger to the wellhead. Another approach has been to use the sealing element itself as a locking mechanism. In these approaches, lockdown as well as sealing is thus provided by the seal. Further, a lockdown style hanger may be utilized to lock the casing hanger in place. This requires an extra trip to install the lockdown style hanger.
SUMMARY OF THE INVENTION
[0007] Disclosed herein is an example of a seal assembly for use in a wellhead assembly which includes an annular seal body which is made up of an elongate inner leg, an elongate outer leg set radially outward from the inner leg, and an elongate slot defined between the inner and outer legs. Wickers are provided on a curved surface of the seal body and selectively engage a tubular surface within the wellhead assembly. The wickers can be on the inner leg, the outer leg, or on both legs. Optionally, the tubular can be a casing hanger, tubing hanger, or wellhead housing. The seal assembly can further include a protective foam layer adhered to the wickers.
[0008] Also disclosed herein is a wellhead assembly which includes inner and outer wellhead tubulars, an annulus between the inner and outer tubulars, and an annular seal in the annulus. In this example the annular seal is made up of an inner leg that is in selective sealing contact with the inner tubular, an outer leg that is in selective sealing contact with the outer tubular, a space between the inner and outer legs, and wickers on a circumference of a curved surface of the seal. In an example, the wickers are on an inner surface of the inner leg and project into an outer surface of the inner tubular. Optionally, the wickers can be on an outer surface of the outer leg and project into an inner surface of the outer tubular. In another example, wickers are on an inner surface of the inner leg and are on an outer surface of the outer leg. An inlay may be set in one of the inner and outer tubulars and strategically located for engagement with the wickers when the legs are in sealing contact with the tubulars. In one example the seal includes nickel alloy.
[0009] A method of sealing an annulus between an inner and outer tubular in a wellhead assembly is disclosed herein. In one example the method includes providing a seal assembly with an annular seal body with inner and outer legs, and with wickers that circumscribe a curved surface on the body, inserting the seal assembly into the annulus, and urging the inner and outer legs radially apart and into respective sealing engagement with an outer surface of the inner tubular and an inner surface of the outer tubular. The wickers can be on an outer surface of the outer leg and embed into the inner surface of the outer tubular during the step of urging the legs apart. In an alternative, the wickers can be on an inner surface of the inner leg and embed into the outer surface of the inner tubular when the legs are urged apart. The method can further involve removing the seal assembly from the wellhead assembly, applying a protective layer onto the wickers, and repeating the steps of inserting and urging apart.
BRIEF DESCRIPTION OF DRAWINGS
[0010] Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:
[0011] FIG. 1 is a side sectional view of an example of a seal assembly in accordance with the present invention.
[0012] FIG. 1A is a side sectional and enlarged view of a portion of the seal assembly of FIG. 1 .
[0013] FIG. 2 is a side sectional view of an alternate embodiment of the seal assembly of FIG. 1 and in accordance with the present invention.
[0014] FIG. 3 is a side sectional view of the seal assembly of FIG. 1 installed in a wellhead assembly.
[0015] While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF INVENTION
[0016] The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.
[0017] It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.
[0018] Shown in FIG. 1 in side sectional view is an example embodiment of a wellhead assembly 10 in which a production casing hanger 12 is shown landed onto an intermediate casing hanger 14 . A downward facing shoulder 15 on production casing hanger 12 contacts an upward facing shoulder 16 on an upper terminal surface of casing hanger 14 . An annular wellhead housing 18 circumscribes both the production hanger 12 and intermediate hanger 14 . An annulus 20 extends axially between the intermediate hanger 12 , and wellhead housing 18 . In the example of FIG. 1 , an upper end of annulus 20 is defined by the sealing interfaces created between the outer seal leg 30 and wellhead housing 18 as well as the inner seal leg 28 and intermediate hanger 14 .
[0019] Inserted within annulus 20 is a seal assembly 22 shown urged into sealing contact with the respective outer and inner surfaces of intermediate casing hanger 14 and wellhead housing 18 . An annular retaining ring 24 threadingly engages an upper end of the seal assembly 22 and annular energizing ring 26 is shown inserted within the seal assembly 22 . Energizing Ring 26 urges inner leg 28 of the seal assembly 22 radially inward and against the intermediate casing hanger 14 . Energizing ring 26 also urges outer leg 30 of seal assembly 22 radially outward against casing hanger 18 . The seal assembly 22 is an annular member having a curved surface along its outer radius and inner radius. The legs 28 , 30 are elongate members whose elongate sides extend in a direction substantially parallel with an axis A X of the seal assembly 22 . Outer leg 30 , which is shown into sealing contact with an inner surface of wellhead housing 18 , further includes wickers 34 on its outer radial surface, and which extend an axial length on the outer radial surface.
[0020] When the seal assembly 22 is energized and outer leg 30 is urged radially outward, wickers 34 project radially outward and into the wellhead housing 18 ; a sealing surface is formed along the interface between the outer leg 30 and wellhead housing 18 . The material of the seal assembly 22 is harder than material of the wellhead housing 18 so that the wickers 34 can penetrate and plastically deform the wellhead housing 18 . An optional inlay 36 may be strategically located on the inner circumference of the wellhead housing, so the wickers 34 engage the inlay 36 when seal assembly 22 is energized. In this example, inlay 36 can be formed from a metal softer than wellhead housing 18 and the metal making p seal assembly 22 . Example materials for the seal assembly include nickel-based alloys, such as Inconel® 718. In addition to providing a sealing interface between the seal assembly 22 and wellhead housing 18 , engaging wickers 34 with wellhead housing 18 can also create a coupling which opposes axial respective movement between seal assembly 22 and wellhead housing that may be introduced by thermal expansion and other similar occurrences.
[0021] Referring now to FIG. 1A , an enlarged view of a portion of the wellhead assembly 10 is shown in side sectional view. In this example, wickers 34 are generally triangular elements with a tip 37 with sharp pointed ends. The sharp ends reduce the force required to embed the wickers 34 into wellhead housing 18 and plastically deform the material of the wellhead housing 18 . Although the wickers 34 are shown as adjoining, spaces may be included between adjacent wickers 34 , or optionally spaces may exist between adjacent groups of wickers 34 . In one example, the distance between adjacent tips 37 is about 0.125 inches. Additionally, the material of what is being deformed by the wickers 34 (e.g. the casing 14 , housing 18 , or inlays 36 , 40 ), can have a hardness that ranges from about 45% to about 55%, or more, of the hardness of the material of the seal assembly 22 .
[0022] Referring back to FIG. 1 , inner leg 28 may also include wickers 38 that are shown engaging with an outer radial surface of casing hanger 16 and plastically deforming that portion to create a sealing interface between inner leg 28 and casing hanger 16 . Optionally, an inlay 40 may be provided on the outer surface of casing hanger 16 and strategically located so that inlay 40 is engaged by wickers 38 . Similar to inlay 36 , inlay 40 may be formed from a material softer than the material used for forming production casing hanger 12 and/or inner leg 28 . Optional embodiments exist, wherein no inlays are provided on either of the casing hanger 16 or wellhead housing 18 . Further optionally, wickers 34 may be provided on a single one of the legs 28 , 30 ; in this example the other leg 28 , 30 would be substantially smooth.
[0023] FIG. 2 illustrates an alternate embodiment of the seal assembly 22 A in an uninstalled configuration wherein the energizing ring 26 is set upward from its energizing position of FIG. 1 . In this example, an upward facing shoulder on the outer radial surface of the energizing ring 26 is in contact with a lower terminal end of the retaining ring 24 . Further in the example of FIG. 2 , foam 42 is provided on the wickers 34 on the outer leg 30 . Also in the example of FIG. 2 , the inner radial surface of inner leg 28 is substantially smooth and having no wickers 34 formed thereon as mentioned above. In this example, the foam 42 fills the space between adjacent wickers 34 . In an example, the foam includes gas filled beads suspended in a matrix, such as a binding agent or resin. The beads (not shown) can be glass. By axially urging energizing ring 26 downward so that its lower nose enters space 32 between legs 28 , 30 , wickers 34 are urged radially outward. In an example, the resulting forces from energizing the seal assembly 22 , 22 A crushes the foam 42 and releases a volume of gas trapped inside the glass beads which reduces the hydraulic pressure that builds between the wicker tips 37 as the seal assembly 22 , 22 A is energized in a submerged environment into particles that do not interfere with formation of the sealing interface between wickers and the associated tubular in which the wickers are embedded. Advantages of the embodiments described herein are that the seal element 22 can be constructed from a much higher yield strength than the wellhead housing 18 or the casing hangers 12 , 14 , which in turn allows much greater lockdown capacities to be achieved. While at surface, the seal assembly 22 , 22 A can either be replaced or repaired, and a fresh amount of foam 42 reapplied before inserting the replacement or repaired seal assembly 22 , 22 A back into the wellhead assembly 10 . Current known embodiments of seal assemblies with wickers are provided on tubulars, which are usually not pulled when replacing a seal, and as such wickers will no longer benefit from the original volume of foam during a reinstallation of a seal assembly because the foam is crushed and consumed during an initial seal assembly installation.
[0024] The wellhead assembly 10 is shown in FIG. 3 and which includes a production tree 44 mounted on wellhead housing 18 . In this example embodiment, production casing hanger 12 and intermediate casing hanger 14 are circumscribed by wellhead housing 18 and seal assembly 22 is shown set in the annulus between tubing and casing hangers 12 , 14 and wellhead housing 18 . Further shown in FIG. 3 is the wellbore 46 over which wellhead assembly 10 is mounted. Depending into wellbore 46 is a casing string 48 whose upper end is attached to intermediate casing hanger 14 , and which circumscribes a tubing string 50 which is supported on production casing hanger 12 . In the example of FIG. 3 , wellhead assembly 10 can be subsea or on surface and used for controlling fluids produced from within wellbore 46 .
[0025] The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.
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An annular seal for use in a wellhead assembly has inner and outer legs that each extend in a direction that is generally parallel with an axis of the seal to define an annular space therebetween. Wickers are provided on an outer surface of the seal, so that when the seal is energized and the legs are urged radially apart from one another, the wickers engage with a mating surface of a downhole tubular. Embedding the wickers into the tubular creates a flow barrier across the interface between the seal and the tubular. The wickers deform the surface of the tubular, which creates a lock down force that opposes relative axial movement of the tubular.
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FIELD OF THE INVENTION
The present invention relates to field-effect transistors and, more particularly, to dual-gated field-effect transistors.
BACKGROUND OF THE INVENTION
A field-effect transistor (FET)is a type of transistor commonly used in Ultra Large Scale Integration (ULSI). In the FET, current flows along a semiconductor path called the channel. At one end of the channel, there is an electrode called the source. At the other end of the channel, there is an electrode called the drain. The physical dimensions of the channel are fixed, but its number of electrical carriers can be varied by the application of a voltage to a control electrode called the gate. The conductivity of the FET depends, at any given instant in time, on the number of electrical carriers of the channel. A small change in gate voltage can cause a large variation in the current from the source to the drain. This is how the FET amplifies signals. In one popular type of FET, known as a MOSFET, the channel can be either N-type or P-type semiconductor. The gate electrode is a piece of metal whose surface is insulated from the channel by an oxide layer between the gate electrode and the channel. Because the oxide layer acts as a dielectric, there is little current between the gate and the channel during any part of the signal cycle. This gives the MOSFET an extremely large input impedance.
As semiconductor devices, such as FETs, have become smaller, a number of techniques have been employed to ensure that performance, speed, and reliability of the devices are not adversely affected. One technique, useful for a number of different devices, includes Silicon-On-Insulator (SOI) structures in which a silicon layer has a buried oxide layer (BOX) between it and a handle wafer. The active elements (e.g., transistors) are fabricated in the silicon layer over the BOX. The BOX is present to provide thick, robust vertical isolation from the substrate thereby resulting in better turn-off characteristics and low capacitance. One method of forming an SOI substrate is to bond two oxidized wafers, then thin one of those wafers so as to form a silicon layer of a thickness appropriate for device fabrication. This structure leaves a thin silicon layer above a layer of oxide.
Another technique, specifically for improving field-effect transistors, involves using dual-gates. In a dual-gated transistor, a top gate and a bottom gate are formed around an active region. Specifically, the advantages for dual gate devices over their single gate counterparts include: a higher transconductance and improved short-channel effects. The improved short-channel effects circumvent problems involving tunneling breakdown, dopant quantization, and dielectric breakdown associated with increasingly high channel doping of shrinking single gate devices. These benefits depend on the top and bottom gates being similar in construction and properly aligned in the vertical direction and aligned with the source/drain regions.
SOI techniques have been used in previous attempts at forming dual-gated devices. In these attempts, the buried oxide layer under a portion of the SOI island is removed, usually by dipping in an etchant, to gain access to the bottom surface of the silicon. Once exposed, a dielectric can be grown on this bottom surface and a gate conductor material deposited. One significant shortcoming of this technique is that the top gate and the bottom gate are not precisely aligned. Accordingly, the advantages of dual-gating are diminished or lost.
One recent attempt to form dual-gated devices that have self-aligned gates is the FinFET. Unlike traditional devices, FinFETs are constructed vertically rather than horizontally and, thus, requires a difficult-to-perform directional etch to determine the device gate length. As gate length is one of the most critical characteristics of a device and its behavior, the fabrication steps that define gate length should be easy to control, very reliable, and easy to duplicate.
Accordingly, there remains a need for a dual-gated device formed horizontally that has self-aligned top and bottom gates. Additionally, there remains a need for a method of forming these gates that simply, accurately, and reliably controls the gate length during fabrication.
SUMMARY OF THE INVENTION
Accordingly, embodiments of the present invention use an SOT structure to form a wrap-around gate electrode for a FET. By wrap-around gate, it is meant that the gate electrode material encircles the periphery, or a majority thereof, of the silicon channel used to form the source and drain regions. In particular, a vertical reference edge is defined, by creating a cavity within the SOI structure, and used during two etch-back steps that can be reliably performed. The first etch-back removes a portion of an oxide layer, for a first distance, over which a gate conductor material is applied. The second etch-back removes a portion of the gate conductor material for a second distance. The difference between the first and second distances defines the gate length of the eventual device. After stripping away the oxide layers, a vertical gate electrode is revealed that surrounds the buried silicon island on all four side surfaces.
One aspect of the present invention relates to a method for forming a wrap-around-gate field-effect transistor, gated on all four active surfaces by a self-aligned electrode, on a handle wafer. In accordance with this aspect, an SOI structure is formed on the handle wafer and then a cavity is formed in this structure extending from its top surface to the handle wafer. Within the cavity, an oxide material is etched back so as to expose the sides of a buried SOI island. With the sides of the SOI island exposed, a gate conductor material can be deposited thereon. This gate conductor material can then, itself, be etched back thereby forming a self-aligned gate electrode that surrounds the SOI island on its four sides.
Another aspect of the present invention relates to a portion of a wrap-around-gated field-effect transistor. This portion includes a handle wafer, an SOI island and a gate electrode. More particularly, the SOI island includes four side surfaces and extends, for its length, in the horizontal direction. The gate electrode surrounds and supports the SOI island. The gate electrode extends in a vertical direction from the handle wafer and has a thickness smaller than the SOI island's length. In other words, the gate electrode includes a first portion below the SOI island, a second portion on one side of the SOI island, a third portion on another side of the SOI island, and a fourth portion above the SOI island such that the gate
Yet another aspect of the present invention relates to a field-effect-transistor that includes a silicon-on-insulator (SOI) island having a top surface, a bottom surface, a right-side surface, a left-side surface, and two edge faces, wherein the SOI island is oriented substantially in a horizontal direction. This transistor also includes a wrap-around gate electrode oriented in substantially a vertical direction intersecting with the SOI island in-between the two edge faces such that the SOI island surrounds the SOI island along a portion of the top surface, the bottom surface, the right-side surface and the left-side surface. Additionally, the transistor includes a source region formed on a first part of the SOI island on one side of the gate electrode; and a drain region formed on a second part of the SOI island on another side of the gate electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a perspective view of a SOI structure having a silicon island surrounded by an oxide.
FIG. 2 illustrates a cross-sectional view of the structure of FIG. 1 .
FIG. 3 illustrates the structure of FIG. 1 with an etching boundary defined on its top surface.
FIG. 4 illustrates a cross section of an SOI structure after a cavity has been formed along its entire thickness.
FIG. 5 illustrates the structure of FIG. 4 after the oxide has been etched-back a predetermined distance.
FIG. 6 illustrates a top view of the structure of FIG. 5 showing the outline of the oxide.
FIG. 7 illustrates a cross-sectional view of an intermediate stage of the structure of FIG. 5 after a gate dielectric, a gate conductor material and fill material have been formed within the cavity.
FIG. 8 illustrates the structure of FIG. 7 after the gate conductor material has been etched-back a predetermined distance.
FIGS. 9 and 10 illustrate different views of the structure of FIG. 8 that has been cut into separate devices and had the fill material within the cavity removed.
FIGS. 11 and 12 illustrate different views of the structure of FIG. 10 after a hard mask layer has been removed from the top of that structure.
FIGS. 13 and 14 illustrate different views of the structure of FIG. 12 after the oxide layers outside of the gate conductor material has been removed.
FIGS. 15A and 15B illustrate different views of an alternative structure to that of FIG. 13 .
FIG. 16 illustrates the structure of FIG. 13 along with electrodes connected to the gate, source and drain regions.
DETAILED DESCRIPTION
The structure 100 shown in the perspective view of FIG. 1 is a typical SOI structure formed using conventional patterning and etching techniques. A wide variety of methods of forming the SOI structure 100 can be employed. This SOI structure 100 includes a handle wafer 102 that in many applications can be a non-silicon material such as a nitride and will have a thickness of approximately 200 nm-1mm. Alternatively, if a silicon handle wafer is employed, it can be capped with a nitride layer (not shown) to prevent interaction of the silicon with other materials.
The central region of the structure 100 is an oxide such as, for example silicon dioxide. This central region includes a buried oxide (BOX) layer 104 and a cap oxide layer 105 . Within the oxide layers 104 , 105 is a silicon-on-insulator (SOI) island 108 . On top of the cap oxide layer 105 , a hard mask 106 is formed.
FIG. 2 illustrates a cross-sectional view of the exemplary structure 100 taken along the plane A-A depicted in FIG. 1 . From this view, it is apparent that in this embodiment the SOI island 108 extends the entire length of the structure 100 and that the oxide layers 104 , 105 are approximately as thick above the island 108 as below the island 108 . However, these relative dimensions can vary without departing from the scope of the present invention. In practice, the BOX layer 104 is typically between 100 to 1000 nm thick as is the cap oxide layer 105 . The SOI island 108 generally ranges between 20 to 250 nm thick.
It is from this structure 100 that the wrap-around-gate of the present invention is formed. A cavity 402 is formed in the structure 100 as shown in FIGS. 3 and 4 . In particular, conventional photolithography techniques, such as a photo resist layer, are used to print a etching region 302 on the hard mask 106 to define the boundaries of an etching step. Once the boundaries are defined, the cavity 402 is etched through the hardmask layer 106 , the cap oxide layer 105 , the island 108 and the BOX layer 104 below the island 108 . After etching, the resist layer is stripped off the hard mask 106 . One of ordinary skill would recognize that a variety of etching compounds are available that can remove these layers in one step or in a plurality of steps. Furthermore, the etching can be performed in a timed-manner or simply by relying on selectivity between the various materials to ensure that only portions of the desired layers are removed.
As shown in the cross-sectional view of FIG. 4 , the etching step to form the cavity 402 is performed so as to form substantially vertical sidewalls 404 , 406 As a result, an SOI island 108 is created on each side of the cavity 402 . The width 306 of the etching region 302 , and therefore of the cavity 402 as well, is approximately between 50 to 200 nm. The length 304 , however, depends on the application. For example, the structure of FIG. 1 only has a single SOI island 108 and the length 304 would typically only need to be enough to overlap each edge of the island 108 by around 20 nm. If however, a plurality of side-by-side SOI islands were formed between oxide layers 104 and 105 , then the length 304 would typically need to be enough to overlap the outside islands by around 20 nm. Thus, as SOI islands can vary between 25-2000 nm, the length 304 can vary widely based on the size of the island and the number of buried SOI islands.
The next step in the process is to use the cavity 402 to etch the cap oxide layer 105 and the BOX layer 104 . For example, buffered hydrofluoric acid (BHF) can be used to etch the oxide (layers 104 , 105 ) but it will not remove any of the SOI island 108 , the hard mask 106 , or the handle wafer 102 . The etch of the BOX layer 104 is timed or controlled so as to create the cross section profile shown in FIG. 5 . Because the etch of the oxide layers 104 , 105 occurs in three dimensions, the sides, top and bottom of each SOI island 108 are exposed.
FIG. 6 is a top view of the structure 500 of FIG. 5 with some of the visible features omitted. In particular, FIG. 6 highlights the shape 602 of the cap oxide layer 105 and the BOX layer 104 after the etching step with BHF is completed. While not shown in FIG. 6 for clarity, the hardmask 106 and island 108 also would extend into the region 602 and be visible from a top view. Dotted lines 604 and 606 depict the outline of the buried island 108 .
FIG. 7 illustrates a cross-sectional profile of the SOI structure after completion of a number of intermediate steps. The first step is to form gate dielectric material 703 on all the exposed surfaces of each SOI island 108 . Once this gate dielectric 703 is formed, a gate conductor material 702 , such as polysilicon, is conformally deposited over the hard mask 106 and within the cavity 402 at a thickness of about 50 nm. This material coats the exposed surfaces of all the layers within the cavity 402 . In particular, the conformal gate conductor material 702 coats the top, bottom, face, and sides of the SOI island 108 , which are coated with the gate dielectric 703 . In one embodiment of the present invention, the gate conductor material 702 substantially fills the cavity 402 and no other material-depositing steps are used.
However, the cross-sectional view of FIG. 7 illustrates an alternative embodiment, in which the gate conductor material 702 does not fill the cavity 402 . In this embodiment, a gap-fill material 704 , usually an organic material, is used to substantially fill the cavity 402 once the gate conductor material 702 is deposited. Using the hardmask 106 as the guide, directional etching, such as reactive ion etching (RIE), is used to remove some of the gap-fill material 704 within the cavity 402 to create substantially vertical sidewalls. The etching of the gap-fill material 704 is continued until a portion 706 of the gate conductor material 702 on the edge face of each SOI island 108 is exposed within the cavity 402 . At this point, the SOI structure 100 is as illustrated in FIG. 7 .
Next, referring to FIG. 8 , the gate conductor material 702 is isotropically etched back as shown by region 802 . Throughout the cavity 402 , all exposed gate conductor material 702 is uniformly etched back. Referring back to FIG. 5 , the oxide layers 104 , 105 were isotropically etched-back a first distance, such as 100 to 500 nm. Now, the gate conductor material 702 is being etched back a second distance 802 , such as 90 to 400 nm. The difference between these two distances is what determines the channel length (i.e., the length of the region between the source and drain, of the resulting transistor) and will be approximately 10 to 120 nm.
The structure of FIG. 8 is then modified by stripping the organic gap-fill material 704 from within the cavity 402 . A perspective view of the resulting structure is depicted in FIG. 9 . From FIG. 6 and FIG. 7 , it can be determined that the gate conductor material 702 follows the profile of the oxide layers 104 , 105 and, therefore, is substantially annular in shape. Thus, the gate conductor material 702 contacts both buried islands 108 . To form discrete structures, the sides of the annular gate conductor material can be trimmed, as shown in FIG. 9 , so as to create two separate gates 904 and 906 . Of particular interest, the gates 904 , 905 have a conductor region, such as 902 , that wraps around the respective island 108 . FIG. 10 shows a cross-sectional profile of the structure of FIG. 9 . The C-shaped profile of the portions 904 and 906 is a result of using the gap-fill material 704 in previous fabrication steps. An alternative embodiment is illustrated later that does not use the gap-fill material and has solid portions in place of the C-shaped profiles of gates 904 , 906 . The gate dielectric 703 can be trimmed back now, as shown in FIG. 10 , or etched away at a later stage to expose the surfaces of the SOI island 108 .
After the hardmask 106 has been stripped, the structure is nearing its final form as shown in FIG. 11 . FIG. 12 is a cross-sectional profile view of FIG. 11 and shows that one side of each island 108 still has oxide layers 104 and 105 present. Accordingly, it would be difficult to connect a contact, or other material layer, to this section 1202 as depicted in FIG. 12 . Accordingly, the oxide layers 104 and 105 can be stripped, as depicted in FIG. 13 , to result in two wrap around gates 904 and 906 that each surround a respective portion of the SOI island 108 .
As more clearly seen in the cross-sectional profile of FIG. 14 , the top and bottom portions of each gate 904 and 906 are aligned with each other and with the source and drain regions. The source and drain regions 1402 , 1404 are exposed, and contacts to all regions can be easily formed. As understood, by one of ordinary skill, the exposed source/drain regions 1402 , 1404 are doped with group 3 or group 5 elements before the contacts are formed. Thus, an SOI device having self-aligned wrap-around gates is formed in such a manner that channel length can be easily controlled using two etch-back steps instead of a difficult long directional etch.
FIGS. 15A and 15B illustrate an alternative embodiment of the device of FIG. 14 . In particular, the mechanical strength of the SOI island 108 can be enhanced by stripping away all the BOX material 104 except that under the SOI island 108 . A directional etching method, such as RIE, could be used to effect such a result. Even in this embodiment, the top of the SOI island 108 remains exposed to facilitate later processing steps such as passivation or salicidation. A second difference illustrated in FIGS. 15A and 15B involves the gate structures 1502 and 1506 .
Referring back to FIG. 7 , gate conductor material 702 and gap-fill material 704 were used to fill the cavity 402 . However, if only gate conductor material 702 had been used, then the subsequent etching steps would have resulted in the gate structures 1502 and 1506 . In particular, these structures 1502 and 1506 do not have the C-shaped profile that is exhibited by the gate structures 904 and 906 of FIG. 10 .
FIG. 16 illustrates the wrap-around gate structure of FIG. 13 with contact formed on the source/drain regions as well as on the gates 904 , 906 . For example, the contact 1606 provides connectivity with the gate 906 ; the contact 1602 provides connectivity with one of the source/drain regions of the island 108 ; and contact 1604 provides connectivity with the other source/drain region of the island 108 .
One of ordinary skill would recognize that there are still further modifications and variations that can be made to the disclosed exemplary embodiments without deviating from the intended scope of the present invention. For example, the exemplary silicon island 108 herein described includes substantially a rectangular cross-sectional profile. In addition to this particular shape, other styles of islands, such as circular, trapezoidal, and polygonal, can be adapted to wrap-around gates as well. Additionally, the wrap-around gate does not have to completely encircle the silicon island as herein described. Performance improvements are still achieved if the wrap-around gate encircles more than a majority around the periphery of the silicon island. By encircling the silicon island by at least that much, the wrap-around gate is able to act as two gate electrodes on opposite sides of the silicon island. Also, the semiconductor island within the SOI structure can include other semiconductor materials in conjunction with, or in replacement of, the exemplary silicon island herein described.
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A field effect transistor is formed having wrap-around, vertically-aligned, dual gate electrodes. Starting with an silicon-on-insulator (SOI) structure having a buried silicon island, a vertical reference edge is defined, by creating a cavity within the SOI structure, and used during two etch-back steps that can be reliably performed. The first etch-back removes a portion of an oxide layer for a first distance over which a gate conductor material is then applied. The second etch-back removes a portion of the gate conductor material for a second distance. The difference between the first and second distances defines the gate length of the eventual device. After stripping away the oxide layers, a vertical gate electrode is revealed that surrounds the buried silicon island on all four side surfaces.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of provisional application Ser. No. 60/154,860 filed Sep. 20, 1999.
FIELD OF THE INVENTION
This invention relates to the production of industrial chemicals. More specifically, the invention describes a novel process for producing chlorine dioxide through the reduction of ammonium chlorate in an aqueous acidic solution.
BACKGROUND OF THE INVENTION
Until recently, chlorine was used as a bleaching agent in the production of white pulp and paper. However, environmental protection agencies have prohibited the use of chlorine for pulp bleaching since it has been found to produce highly hazardous organochlorine compounds. Chlorine dioxide has replaced chlorine as the primary bleaching agent in the production of white pulp and paper. Chlorine dioxide is also used for water purification. It is now the most important worldwide commodity for these purposes.
Existing technologies for commercial production of chlorine dioxide involves the reduction of sodium chlorate/chloric acid with reducing agents such as hydrogen peroxide and glycerol, glycol (See e.g. U.S. Pat. Nos. 5,093,097; 5,091,166; 5,380,517; 5,486,344; and 5,487,881 and Japanese Pat. No. JP88-8203), methanol (U.S. Pat. Nos. 4,978,517 and 5,174,868) and chloride (U.S. Pat. No. 5,458,858; Canadian Pat. Nos. 461586 and 782574). The disclosures of these listed patents are hereby incorporated by reference. These commercial processes incorporate the following chemical reactions:
6NaClO 3 + 3H 2 SO 4 + 3H 2 O 2
→
6ClO 2 + 6H 2 O + 3Na 2 SO 4 + 3O 2
6NaClO 3 + 3H 2 SO 4 + 2CH 3 OH
→
6ClO 2 + 5H 2 O + 3Na 2 SO 4 + O 4 +
2HCOOH
NaClO 3 + Alcohols + H 2 SO 4
→
ClO 2 + Na 2 SO 4 + CO 2 + H 2 O
6HClO 3 + 3H 2 O 2
→
6ClO 2 + 6H 2 O + 3O 2
6NaClO 3 + 12HCl
→
6ClO 2 + 3Cl 2 + 6H 2 O + NaCl
There are many drawbacks involved with the use of these existing technologies. For instance, methanol is a poisonous and volatile chemical. In addition, as shown above, the major oxidized product formed in methanol reduction processes is formic acid, which is also a toxic chemical. Thus, the use of methanol as a reducing agent in the production of chlorine dioxide creates an environmental hazard.
Chloride as a reducing agent is supplied either as hydrogen chloride or as sodium chloride. While chloride is not expensive, its use as a reducing agent in these processes is also disadvantageous since it makes chlorine dioxide with large amounts of chlorine impurity. This is problematic since there has traditionally been no practical means of disposing of chlorine waste material.
The use of methanol as a reducing agent in chlorine dioxide processes also has the disadvantage of producing the inevitable by-product sodium sulfate (Na 2 SO 4 ), which is commercially known as salt cake. A part of the salt cake by-product is consumed by pulp mills to make sodium sulfide, a component of black liquor. However, the bulk of the salt cake does not have any use and must simply be disposed of.
Hydrogen peroxide can also be used as an efficient reducing agent in the production of chlorine dioxide. Although expensive, the use of hydrogen peroxide is an attractive alternative since it does not result in the formation of the formic acid and chlorine toxic by-products. However, the use of hydrogen peroxide also results in the production of large amounts of undesirable salt cake as a waste product.
There is therefore a need in the art for an improved method of producing chlorine dioxide.
It is therefore a primary objective of the present invention to provide a method of producing chlorine dioxide which does not form toxic by-products and is environmentally safe.
It is a further objective of the present invention to provide a means of producing chlorine dioxide in higher yield with a faster reaction rate than commercially known processes.
It is yet a further objective of the present invention to provide a means of producing chlorine dioxide which is economical.
It is a further objective of the present invention to provide a means of producing chlorine dioxide without the need for recycling the by-products.
These and other objectives will become apparent from the following description.
SUMMARY OF THE INVENTION
The present invention describes a method of producing chlorine dioxide using a novel chemical reaction. Specifically, the invention involves the chemical reduction of ammonium chlorate in an aqueous acidic solution. The reducing agent may include any one of hydrogen peroxide, sugars, alcohols, aldehydes, ketones, organic acids, sulfur dioxide, ammonium sulfite, ammonium bisulfite, or mixtures thereof. The reduction reaction is performed with or without a catalyst at elevated temperatures.
The yield of chlorine dioxide in this invention is over 110% on the basis of reducing agents than in existing processes, as well as at least a 50% higher rate. Further, the resulting chlorine dioxide is substantially free of chlorine impurity. Using sulfuric acid as the acidifying agent, ammonium sulfate is produced as a by-product which may be used as a fertilizer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As set forth above, the present invention discloses the production of chlorine dioxide through the reduction of ammonium chlorate in an aqueous acidic solution, preferably in the absence of a substantial amount of sodium ions, meaning that there are insignificant amounts of sodium ions to produce salt cake by-product.
Any source of ammonium chlorate is suitable for this invention. The ammonium chlorate is preferably prepared by the double decomposition reaction of ammonium sulfate and barium chlorate, and most preferably as described in U.S. Pat. No. 5,948,380, the disclosure of which is hereby incorporated by reference. The concentration of chlorate ion (ClO 3 − ) in the aqueous acidic solution is preferably maintained at about 0.5M to saturation, and most preferably between about 1.5M to 4.5M.
The source of acidity for this invention may be any strong acid, with sulfuric acid, ammonium bisulfite, chloric acid, perchloric acid, and mixtures thereof being preferred.
There are four preferred categories of aqueous acidic solutions for use in the invention. The first category is aqueous solutions of chloric acid or a mixture of chloric acid and ammonium chlorate with acidity ranging preferably from about 0.2N to 7N, and most preferably from about 1.5N to 5N. The chloric acid feed solution is available from the reaction of sulfuric acid with barium chlorate. The preparation of barium chlorate is described in U.S. Pat. No. 5,948,380.
The second preferred category of aqueous acidic solutions is aqueous solutions of perchloric acid or a mixture of perchloric acid and chloric acid or a mixture of perchloric acid and chloric acid, with acidity ranging preferably between about 0.2N to 1N, and most preferably between about 1.5N to 5N. The perchloric acid for making such mixtures is available commercially.
The third preferred category of aqueous acidic solutions is aqueous solutions of chloric acid and sulfuric acid, with acidity ranging preferably between about 1N to 14N, and most preferably between about 2N to 8N.
The fourth preferred category of aqueous acidic solutions is aqueous solutions of sulfuric acid and ammonium bisulfate and ammonium sulfate, with acidity ranging preferably between about 1N to 14N, and most preferably between about 2N to 8N. The source of aqueous acidity in these solution is sulfuric acid and ammonium bisulfate.
The concentrated aqueous solution of the reducing agent is fed into a reactor so as to maintain a concentration of reducing agent ranging from about 0.00005M to 0.88M in the reaction mixture. The preferred concentration of reducing agent is from about 0.005M to 0.4M, with the most preferred concentration being maintained in a range of from about 0.01M to 0.2M.
The reducing agent used in this invention is not critical, and may include any conventional reducing agents. These may include, but are not limited to hydrogen peroxide, sugars, alcohols, aldehydes, ketones, organic acids, sulfur dioxide, ammonium sulfite, ammonium bisulfite and mixtures thereof. Preferred sugars for use as a reducing agent in this invention are sucrose, glucose and fructose. Preferred alcohols are methanol, glycerol and ethylene glycol. Preferred acids are oxalic acid, malonic acid, citric acid, tartaric acid, and ascorbic acid. The most preferred reducing agents are hydrogen peroxide, glycerol, and sucrose.
The reduction of ammonium chlorate to chlorine dioxide by the reducing agents is carried out at a temperature ranging from about 20° C. to 100° C., preferably from about 45° C. to 85° C., and most preferably from about 55° C. to 80° C., and at a pressure ranging from about 50 to 800 mm of Hg, and preferably from about 65 to 500 mm of Hg.
Under the above reaction conditions, the reduction of ammonium chlorate in accordance with this invention proceeds smoothly at rates higher than with other industrially used processes using sodium chlorate in the absence of substantial amounts of chloride as a catalyst. As used herein, the phrase “in the absence of substantial amounts of chloride as a catalyst” means there are insufficient amounts of chloride present in the reduction reaction to function as a catalyst. Chloride may, however, be added to the reaction mixture as alkali or earth alkali metal chloride, in particular strontium chloride, hydrochloric acid, or ammonium chloride in an amount ranging from about 0.00001M to 0.6M to accelerate the rate of chlorine dioxide production by these reducing agents. A preferred concentration of chloride catalyst in the reaction is 0.0002M to 0.05M. The addition of ammonium chloride appears to accelerate chlorine dioxide production more than alkali metal chloride, and is therefore the most preferred catalyst. Reduction reactions of this invention may also be catalyzed by transition metal ions, with silver, cobalt, manganese, rare earth metals, or mixtures thereof being preferred. Other appropriate transition metal ions include manganese, cobalt, and strontium.
Under similar acidity, chlorate and sulfate concentrations, the rate of chlorine dioxide production in accordance with this invention is over 50% faster in a reaction mixture containing sulfuric acid, ammonium chlorate, and ammonium sulfate than in a mixture containing sulfuric acid, sodium chlorate and sodium sulfate.
The chemical combination of ammonium chlorate and the preferred reducing agents of this invention and a preferred aqueous acidic solution of sulfuric acid results in the following net reactions to produce chlorine dioxide, ammonium sulfate, nitrogen, and carbon dioxide:
8NH 4 ClO 3 +3H 2 SO 4 +H 2 O 2 →3(NH 4 ) 2 SO 4 +8H 2 O+O 2 +N 2 +8ClO 2
33NH 4 ClO 3 +C 12 H 22 O 11 +18H 2 SO 4 →33ClO 2 +32H 2 O+9(NH 4 ) 3 H(SO 4 ) 2 +12CO 2 +3N 2 sucrose
17NH 4 ClO 3 +C 3 H 9 O 3 +10H 2 SO 4 →17ClO 2 +16H 2 O+5(NH 4 ) 3 H(SO 4 ) 2 +3CO 2 +N 2 glycerol
14NH 4 ClO 3 +C 2 H 6 O 2 +8H 2 SO 4 →14ClO 2 +13H 2 O+4(NH 4 ) 3 H(SO 4 ) 2 +2CO 2 +N 2 ethylene glycol
The major by-product, ammonium sulfate, may be used as a fertilizer or recycled by heating in the presence of a catalyst to produce useful industrial chemicals, such as sulfur dioxide and ammonia (U.S. Pat. No. 4,081,515). Thus, unlike the salt cake by-products of existing chlorine dioxide production processes, the ammonium sulfate by-product of the present invention does not require expensive disposal or reprocessing/recycling.
As shown above, the present inventors have discovered a way of preventing the production of the unwanted chlorine and sodium sulfate by-product generated by chlorine dioxide plants. This finding could potentially save the chemical industry large sums of money which would have otherwise been spent disposing of this waste product.
In addition, the methods of this invention using ammonium chlorate produces chlorine dioxide in a yield of 110% on the basis of reducing agent, and at a greater than 50% higher rate than in conventional processes using sodium chlorate, as demonstrated in Examples 2, 4, and 9 below.
The following examples are offered to illustrate but not limit the invention. Thus, they are presented with the understanding that various formulation modifications as well as reactor modifications may be made and still be within the spirit of the invention.
EXAMPLE 1
Preferred Method of Production of Chlorine Dioxide Using Hydrogen Peroxide as a Reducing Agent
An aqueous solution of 304 g/h NH 3 ClO 3 together with 150 g/h H202 of 30% solution was continuously added to a laboratory chlorine dioxide generator. H 2 SO 4 of 50% concentration was added in order to keep the acid strength of 4.56N. An aqueous solution of 4.0 g NH 4 Cl was also added together with an excess of chlorate solution. The generator was run continuously at a temperature of around 70° C., and chlorine dioxide was collected under reduced pressure of 400 mm of Hg to keep the reaction mixture at boiling during the chlorine dioxide collection. A neutral salt (NH 4 ) 2 SO 4 was crystallized in the crystallization region. The rate of chlorine dioxide production was 7.78 kg/l/d, with a yield of 99% and a rate of production of 8007×10 −5 moles/min/l reaction-mix.
EXAMPLE 2
Preferred Method of Production of Chlorine Dioxide Using Hydrogen Peroxide as a Reducing Agent in Acidic Solution Saturated with Ammonium Sulfate
A mixture of 171 g/h NH 4 ClO 3 and 51 g/h, H 2 O 2 (30%) together with 3.6 g/h NaCl was continuously added to a chlorine production generator. H 2 SO 4 was also fed to the reaction mixture to keep the acid strength of 4.0 N. The reaction mixture was saturated with (NH 4 ) 2 SO 4 . The generator was run continuously at temperature around 80° C., and chlorine dioxide was collected under reduced pressure of 250 mm of Hg in order to keep the reaction mixture at boiling during collection of ClO 2 . A neutral salt (NH 4 ) 2 SO 4 was crystallized in the crystallization region. Production of chlorine dioxide was 4.66 kg/l/d, and the yield was 99% with a rate of chlorine dioxide production of 4800×10 −5 moles/min/l reaction-mix.
This experiment was conducted in accordance with Example 3 of U.S. Pat. No. 5,091,166 to Engström, only substituting ammonium chlorate for the sodium chlorate. While Engström's rate of chlorine dioxide production was only 1.5 kg/l/day, as shown above, Applicant was able to achieve a rate of 5.25 kg/l/day, or a rate 3.1 times higher than that of Engström.
EXAMPLE 3
Preferred Method of Production of Chlorine Dioxide Using Hydrogen Peroxide as a Reducing Agent
An aqueous solution of 134 g/h NH 4 ClO 3 together with 60 g/h H 2 O 2 (30% solution) was continuously added to a laboratory chlorine dioxide production generator. A required amount of H 2 SO 4 was also fed to the reaction mixture to keep the acid strength of 4.0 N. An aqueous solution of 1.96 g/h NaCl was added together with excess NH 4 ClO 3 solution. The generator was run continuously at temperature around 70° C., and chlorine dioxide was collected under reduced pressure of 150 mm of Hg in order to keep the reaction mixture at boiling during collection of ClO 2 . A neutral salt (NH 4 ) 2 SO 4 was crystallized in the crystallization region. Production of chlorine dioxide was 3.62 kg/l/d, and the yield was 95% with a rate of chlorine dioxide production of 3628×10 −5 moles/min/l reaction-mix.
EXAMPLE 4
Preferred Method of Production of Chlorine Dioxide Using Hydrogen Peroxide as a Reducing Agent
A mixture of 172 g/h NH 4 ClO 3 together with 77 g/h H 2 O 2 (30% solution) was continuously added to a laboratory chlorine dioxide production generator. A required amount of H 2 SO 4 was also fed to the reaction mixture to keep the acid strength of 4.0 N. An aqueous solution excess of NH 4 ClO 3 together with 3.25 g/h NaCl was added to the generator. The reaction mixture in the generator was kept at boiling throughout the collection of ClO 2 , and chlorine dioxide was collected at 70° C. under reduced pressure of 150 mm of Hg. A neutral salt (NH 4 ) 2 SO 4 was crystallized in the crystallization region. Production of chlorine dioxide was 4.10 kg/l/d, and the yield was 98% with a rate of chlorine dioxide production of 4218×10 −5 moles/min/l reaction-mix.
This experiment was conducted in accordance with Example 1 of U.S. Pat. No. 5,091,166 to Engström, only substituting ammonium chlorate for the sodium chlorate. While Engström's rate of chlorine dioxide production was only 1.2 kg/l/day, as shown above, Applicant was able to achieve a rate of 4.10 kg/l/day, or a rate 3.4 times higher than that of Engström.
EXAMPLE 5
Preferred Method of Production of Chlorine Dioxide Using Hydrogen Peroxide as a Reducing Agent in Acidic Solution Saturated with Amimonium Sulfate
A mixture of 173 g/h NH 4 ClO 3 together with 51 g/h H 2 O 2 (30% solution) was continuously added to a laboratory chlorine dioxide production generator. A required amount of H 2 SO 4 was also fed to the reaction mixture to keep the acid strength of 4.0 N. An aqueous solution excess of NH 4 ClO 3 together with 3.2 g/h NH 4 Cl was added to the generator. The reaction mixture was saturated with (NH 4 ) 2 SO 4 . The generator was continuous run at a temperature of around 80° C. Chlorine dioxide was collected under reduced pressure of 250 mm of Hg while keeping the reaction mixture at boiling. A neutral salt (NH 4 ) 2 SO 4 was crystallized in the crystallization region. Production of chlorine dioxide was 5.25 kg/l/d, and the yield was 99% with a rate of chlorine dioxide production of 5400×10 −5 moles/min/l reaction-mix.
EXAMPLE 6
Preferred Method of Production of Chlorine Dioxide Using Sugar as a Reducing Agent
A water solution of 225 g/h NH 4 ClO 3 together with 60 g/h sugar (50% aqueous solution) were added continuously to a laboratory reactor. A required amount of H 2 SO 4 (50% solution) was also added to keep the acidity 7N. The reactor was run continuously at temperature around 65° C., and chlorine dioxide was collected under reduced pressure 250 mm of Hg in order to keep the reaction mixture boiling during the collection of chlorine dioxide. The crystals of (NH 4 ) 3 H(SO 4 ) 2 were isolated in the crystal region. The chlorine dioxide production was 4.70 kg/l/d, and yield was 95% with a rate of production of 4837×10 −5 moles/min/l reaction mix.
EXAMPLE 7
Preferred Method of Production of Chlorine Dioxide Using Sugar as a Reducing Agent
7A—NH 1 ClO 3 /Sugar System
To a chlorine dioxide production generator, a aqueous solution of 255 g/h NH 4 ClO 3 and 60 g/h sugar (50% aqueous solution) were added continuously. A 50% solution of H 2 SO 4 was also added to keep the aqueous acidity at 8N. The generator was run continuously at a temperature of around 70° C. while chlorine dioxide was collected under reduced pressure of 250 mm of Hg. Reduced pressure was maintained in order to keep the reaction mixture at boiling. The crystals of (NH 4 ) 3 H(SO 4 ) 2 were isolated in the crystal region. The chlorine dioxide production was 12.50 kg/l/d, and the yield was 99% with a rate of production 12869×10 −5 moles/min/l reaction mix.
7B—NaClO 3 /Sugar System
319 g/h NaClO 3 and 60 g/h sugar (50% solution) was added to a chlorine dioxide production generator. A required amount of H 2 SO 4 was also added to keep acid at 8.0N. The generator was continuously run at 70° C., and chlorine dioxide was continuously collected under reduced pressure of 250 mm of Hg. The production of chlorine dioxide was 7.78 kg/l/d and at a rate of 8000×10 −5 moles/l/min.
Thus, as shown above, the production of chlorine dioxide was much more efficient using Applicant's method using ammonium chlorate than the previous method using sodium chlorate.
EXAMPLE 8
Preferred Method of Production of Chlorine Dioxide Using Sugar as a Reducing Agent
A water solution of 170 g/h NH 4 ClO 3 and 50 g/h sugar (50% aqueous solution) were continuously added to a chlorine production generator at temperature around 80° C. 50% aqueous H 2 SO 4 was added to keep the acid concentration at 8N. The generator was run continuously at a temperature of around 80° C. during which time chlorine dioxide was collected under reduced pressure of 150 mm of Hg. The crystals of (NH 4 ) 3 H(So 4 ) 2 were isolated in the crystal region. The chlorine dioxide production was 24.50 kg/l/d, and the yield was 99% with a production rate of 25185×10 −5 moles/min/l reaction mix.
EXAMPLE 9
Preferred Method of Production of Chlorine Dioxide Using Glycerol as a Reducing Agent
255 g/h NH 4 ClO 3 aqueous solution and 30 g/h glycerol (50% aqueous solution) were added continuously to a laboratory chlorine dioxide generator. A H 2 SO 4 /50% aqueous solution was also added to maintain the acidity of the reaction mixture at 7N. The reactor was run continuously at around 70° C. while chlorine dioxide was collected under reduced pressure at 250 mm of Hg. The crystals of (NH 4 ) 3 H(SO 4 ) 2 were isolated in the crystal region. The chlorine dioxide production was 8.60 kg/l/d, and the yield was 99% with a rate of production 8848×10 −5 moles/min/l reaction mix.
This experiment was conducted in accordance with Example 3 of U.S. Pat. No. 5,093,097 to Engström, only substituting ammonium chlorate for the sodium chlorate. While Engström's rate of chlorine dioxide production was only 1.7 kg/l/day, as shown above, Applicant was able to achieve a rate of 8.60 kg/l/day, or a rate over 5 times hither than that of Engström.
EXAMPLE 10
Preferred Method of Production of Chlorine Dioxide Using Ethylene Glycol as a Reducing Agent
To a laboratory chlorine dioxide generator an aqueous solution of 170 g/h NH4 ClO 3 and 30 g/h ethylene glycol (20% aqueous solution) were added continuously. 50% aqueous H 2 SO 4 solution was added to keep the acidity at 7N. The generator was run continuously at around 65° C. during which time chlorine dioxide was collected at a reduced pressure 350 mm of Hg. Reduced pressure was applied to keep the reaction mixture at boiling. The crystals of (NH 4 ) 3 H(SO 4 ) 2 were isolated in the crystal region. The chlorine dioxide production was 8.75 kg/l/d, and the yield 99% with a rate of production 8992×10 −5 moles/min/l reaction mix.
EXAMPLE 11
Determination of Rates of Chlorine Dioxide Production in Flow Reactor
The rate determination experiments were carried out as described in Examples 1-5. The rates were calculated based on the amount of chlorine dioxide collected, time of collection and the volume of the reaction mixtures. The rates and reaction conditions are given in Table 1 below:
TABLE 1
Results of Flow Reactor Experiments from Hydrogen Peroxide Reduction
Amount
Pressure
Example
of ClO 2
in mm
Catalyst
Temp.,
Molarity of
Normality
ClO 2 rate
Numbers
in g/l/min
of Hg
Catalyst
Molarity
° C.
Chlorate ion
of H 2 SO 4
moles/min./lit.
1
7.78
400
NH 4 Cl
0.0010
70
2.00
4.56
8007 × 10 −5
2
4.66
250
NaCl
0.00045
80
2.00
4.00
4800 × 10 −5
3
3.62
150
NaCl
0.00136
70
2.00
4.00
3628 × 10 −5
4
4.10
150
NH 4 Cl
0.00056
70
2.00
4.00
4218 × 10 −5
5
5.25
250
NH 4 Cl
0.00049
80
2.00
4.00
5400 × 10 −5
Examples 2 and 5 were carried out in a reaction mixture saturated with ammonium sulfate.
EXAMPLE 12
Determination of Rates of Chlorine Dioxide Production in Flow Reactor
The rate determination experiments were carried out as described in Examples 6-10. The rates were calculated based on the amount of chlorine dioxide collected, time of collection and the volume of the reaction mixtures. The rates and reaction conditions are given in Table 2 below:
TABLE 2
Results of Flow Reactor Experiments from Sugar, Glycerol and Ethylene Glycol
Amount
Molarity of
Reducing
of ClO 2
Pressure in
Temp.,
reducing
Molarity of
Normality
ClO 2 rate
Agents
in g/l/min
mm of Hg
° C.
agents
NH 4 ClO 3
of H 2 SO 4
moles/min./lit.
Sugar
4.70
250
65
0.058
2.0
7
4837 × 10 −5
12.50
250
70
0.058
2.0
8
12869 × 10 −5
24.50
150
80
0.073
2.0
8
25185 × 10 −5
Glycerol
8.60
250
70
0.197
2.0
7
8848 × 10 −5
Ethylene
8.75
350
65
0.322
2.0
7
8992 × 10 −5
Glycol
It is therefore submitted that the present invention accomplishes at least all of its stated objectives.
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A novel method is described whereby chlorine dioxide is produced through the chemical reduction of ammonium chlorate in an aqueous acidic solution. The reduction reaction takes place at elevated temperatures with or without a catalyst. The reducing agent of this reaction is preferably hydrogen peroxide, glycerol, or sucrose. Chlorine dioxide may be produced in accordance with this invention at a substantially higher rate and in higher yield than with conventional methods using sodium chlorate. Further, the chlorine dioxide produced is substantially chloride-free. The ammonium sulfate by-product of this method has direct use as a fertilizer.
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STATEMENT OF GOVERNMENT INTEREST
[0001] The Federal government has rights in this invention pursuant to contract no. MDA 90499C2506 between the Department of the Defense and the University of Maryland.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to the use of precisely positioned micron-sized thermally conducting via holes in semiconductor materials to precisely and efficiently remove heat from high heat producing areas in semiconductor components/devices or chips to ambient atmosphere or a heat sink.
[0004] 2. Description of Related Art
[0005] Microelectronic chips are typically thermally insulated by passivation and bulk materials, which make thermal transfer extremely inefficient. As a result, the design and operation of the microelectronic chip is adversely affected. Additionally, significant size and financial costs are associated with removing heat from high performance microelectronic chips.
[0006] Within the microelectronic chip industry, there is a continuous effort to improve operation of microelectronic chips. However, as shown in FIG. 1 , there is a rather significant problem of localized high heating areas 114 among circuit components 112 for chips 110 , which results from high switching frequency and/or high operating voltages or currents. The localized heating problem is typically aggravated by the use of multiple layers of thermally insulating materials 130 , such as oxides and nitrides added for electrical isolation, or use of spin-on-glass (SOG) for environmental protection and packaging. In addition, heat problems can be exacerbated simply by the presence of bulk substrates 120 , which are made primarily of silicon, upon which active devices, e.g., circuit components, are fabricated.
[0007] FIG. 2 illustrates a conventional method of extracting heat from a microelectronic chip 210 via external heat dissipation H. The conventional method involves adding a heat sink 250 , such as metallic fins, mounted to a top surface of the chip 210 . However, the problem of localized high heating areas 214 remains among the components 212 , as a result of, for example, high switching frequency and/or much higher current densities. The higher current densities are a direct result of the continuing trend to put more devices or circuits into a smaller area. Multiple layers of thermally insulating material 230 are disposed between the heat sink 250 and active devices 212 , which are typically manufactured upon a bulk substrate 220 .
[0008] While these methods provide some thermal extraction for the entire chip, unfortunately, the methods are not very efficient and may even be totally ineffective in extracting heat from localized high heat producing areas because of the presence of multiple layers of thermally insulating materials disposed between the heat producing region and the external package and/or heat sink.
[0009] Another conventional method for reducing heat effects involves reducing the thermal budget of the microelectronic chip by imposing operational limits. However, this approach sacrifices the performance of the microelectronic chip.
[0010] Other conventional methods of extracting heat from microelectronic chips include employing micro-fluidic cooling pumps that use micro-channels to pump a coolant around the chip, as disclosed, for example, in U.S. Pat. No. 5,170,319 to Chao-Fan Chu et al. A method of extracting heat from microelectronic chips by controlled spray cooling is disclosed in U.S. Pat. No. 5,992,159 to Edwards et al. In particular, the method of Edwards involves providing a condensed vapor mist on the chip package. Unfortunately, micro-fluidic pumps, as well as the spray cooling method, are difficult to implement. Moreover, rather complex apparatuses must be fabricated and then attached thereto, but without damaging the existing microelectronic chip, which add several levels of risk of component failure, while increasing cost and overall size.
[0011] Yet another method of extracting heat from microelectronic chips is disclosed by U.S. patent application Publication Number 2003/0042006 to German et al., wherein large diameter, through-substrate heat plugs using powder injection molding are employed. While large diameter through-substrate heat plugs are generally more reliable than the above-described conventional heat extraction methods, the large diameter heat plugs generally cannot be fabricated during initial device fabrication and are unable to specifically or accurately target high heat producing areas of the microelectronic chip.
SUMMARY OF THE INVENTION
[0012] To overcome the above-described problems of the conventional and other methods, as well as others, according to an aspect of the present invention, a thermal insulation layer is formed on a surface of a body of a microcircuit having at least one component thereon. The component has at least one high heat producing area that occurs from such factors as a high switching frequency, or current densities, and the like. At least one thermally conducting, e.g., filled with aluminum or some other conductive material, via (also interchangeably referred to herein as “hole”) is formed through an entire thickness of the thermal insulation layer so as to be in direct communication by being either in direct contact or close proximity to the high heat producing area (also interchangeably referred to herein as a “shunt”). It is also possible to etch and form the thermally conducting via, or shunt, through the backside of the substrate material, which may be formed from such materials as silicon or gallium arsenide, upon which the electrical devices and circuits are built or otherwise fabricated. Such vias provide a direct path of thermal extraction from the high heat producing area to a cooler area. The cooler area may be ambient air or an element having a high rate of thermal conductivity, such as a heat sink, that is attached to a surface of the thermal insulation layer remote from the body of the microcircuit.
[0013] The present invention provides several advantages compared to other known thermal extraction approaches. For example, the present invention extracts heat more accurately from required areas as a result of the conductive thermal via shunts capable of being made less than 1 micron in diameter and positioned with extreme precision, i.e., to less than 1 micron accuracy anywhere within the circuit. As a result, the present invention provides a more efficient and cost effective technique for extracting heat from desired areas. Furthermore, because the technology required to place and position the thermal via shunts of the present invention is the same technology used to form the integrated circuits, the technique of the present invention is amenable to processing automation, which results in lower costs.
[0014] Also, the present invention may be particularly advantageous for use with three-dimensional circuits, although the present invention is also useful for two-dimensional circuits. The present invention is also particularly useful in high power applications.
[0015] According to one aspect of the present invention, the body of the microcircuit may be a microelectronic chip having a silicon-based substrate upon which the component is formed. According to another aspect of the present invention, the via may be formed through the entire thickness of the thermal insulation layer by dry etching, wet etching, micro-machining, or using liftoff techniques for layer patterning, or the like.
[0016] Moreover, according to yet another aspect of the present invention, a thermally conductive material may be deposited in the via to increase the rate of heat extraction through the via. The heat sink is preferably formed from a thermally conductive material, such as or including metal. Examples of the thermally conductive material include, but are not limited to, substances containing diamond, graphite, copper, aluminum, gold, and silver. Furthermore, the thermally conductive material may be deposited within the via by any one of physical vapor deposition, chemical vapor deposition, electroplating, vacuum casting, and spin casting.
[0017] According to yet another aspect of the present invention, the structural configuration of the present invention permits determining dimensions of the via using a height-to-width ratio between approximately 20:1 and 10:1. Therefore, when the thermal insulation layer has a thickness of, for example, 1 μm, the via would have a diameter in a range of 0.05 to 0.10 μm. Having such small vias allows placement of the thermal via shunts virtually anywhere near or between devices and circuits.
[0018] Additional advantages and novel features of the invention will be set forth in part in the description that follows, and in part will become more apparent to those in the art upon examination of the following or upon learning by practice of the invention.
BRIEF DESCRIPTION OF DRAWINGS
[0019] The present invention is illustrated by way of example and is not limited by the figures of the accompanying drawings, in which like references indicate similar elements, and in which:
[0020] FIG. 1 is a cross-sectional view of a microelectronic chip;
[0021] FIG. 2 is a cross-sectional view of a microelectronic chip having a heat sink provided thereon for passive heat extraction;
[0022] FIG. 3 is a cross-sectional view of a microelectronic chip having vias filled with conductive material according to an embodiment of the present invention;
[0023] FIG. 4 is a cross-sectional view of a microelectronic chip having vias with conductive material and a heat sink according to another embodiment of the present invention; and
[0024] FIG. 5 is a flow chart illustrating a method for manufacturing the microelectronic chip of the present invention.
DETAILED DESCRIPTION
[0025] An apparatus and method for removing heat from localized high heat producing areas of circuitry in microelectronic systems and devices, such as microelectronic chips, is described. In the following description, specific details are set forth, such as material types, dimensions, processing steps, and the like, in order to provide a thorough understanding of the present invention. However, the invention may be practiced without these specific details. In other instances, well-known elements and processing techniques have not been shown in particular detail in order to avoid unnecessarily obscuring the description of the present invention. This discussion will mainly be limited to those needs associated with removing heat from microelectronic systems and devices. It will be recognized, however, that such focus is for descriptive purposes only and the apparatus and methods of the present invention are applicable to other devices and components.
[0026] FIG. 3 illustrates a cross-sectional view of an examplary microelectronic chip 310 having components and other circuit elements 312 , fabricated thereon and, for example, electrically coupled, in a conventional manner, on a bulk substrate 320 . The active devices 312 are disposed on a top surface 320 t of the bulk substrate 320 . The bulk substrate 320 is typically made of silicon, but may also be manufactured from any other well-known or later developed material having similar properties or applications.
[0027] The components 312 have localized high heat producing areas 314 a , 314 b that occur due to high switching frequency, and/or much higher current densities, high operating voltages or currents, or the like. A thermally insulating material 330 is formed on a top surface 312 a of the components 312 . Although only one layer 330 of thermally insulating material is shown in FIG. 3 , it should be noted that a single layer is illustrated merely to simplify the description of the present invention, and it is within the scope of the invention and would be obvious to one of ordinary skill in the industry to form a plurality of thermal insulation layers 330 on the top surface 312 a of the components 312 .
[0028] As shown in FIG. 3 , an outer surface 330 a of the thermal insulation layer 330 is exposed to the ambient atmosphere. However, in another embodiment of the present invention shown in FIG. 4 , a stiffening plate or heat sink 450 is thermally coupled to or otherwise emplaced on the outer surface 330 a of the thermal insulation layer 330 . The heat sink 450 may be any number of well-known conventional structures used for heat dissipation, such as a finned heat sink, constructed from well-known materials, such as metal. However, it is within the scope of the present invention to manufacture and use a heat sink 450 that is formed from an alternative material having similar strength, thermal and/or other conductivity characteristics as metal.
[0029] As shown in both FIGS. 3 and 4 , at least one heat plug via, or simply via, 360 is defined in the thermal insulation layer 330 and passes completely therethrough. Each via 360 has a first end 360 a at the upper surface 330 a of the thermal insulation layer 330 and a second end 360 b at the lower surface 330 b of the thermal insulation layer 330 . In the embodiment of the present invention shown in FIG. 3 , the first end 360 a of each via 360 communicates with the ambient atmosphere 340 . Alternatively, and in the embodiment of the present invention shown in FIG. 4 , the first end 360 a of each via 360 communicates with a bottom surface 450 b of the heat sink 450 .
[0030] Moreover, in the embodiments of the present invention shown in FIGS. 3 and 4 , the second end 360 b of each via 360 communicates with the top surface 312 a of the components 312 .
[0031] Each via 360 is formed to pass entirely through the thermal insulation layer 330 typically in a manner so as to directly communicate with high heat producing areas, but to avoid contacting existing or future electrical routing, e.g., metal. Each via 360 directly communicates with the corresponding high heat producing areas 314 by either being in direct contact or sufficiently close proximity to extract heat from the high heat producing areas 314 . Moreover, it should be noted that each via 360 may be formed to be less than 1 micron (μm) in diameter and less than 1 micron (μm) from the electrical routing and/or the high heat producing areas 314 . It is within the scope of the present invention to form each via 360 by etching; using liftoff techniques for layer patterning; LIGA, a German acronym for Lithographic, Galvanoformung, und Abformung; sacrificial bulk and surface micromachining; and any other known or future developed opening or aperture forming process. It should be noted that each via 360 can be formed by dry etching or wet etching. For example only, such dry etching processes as reactive ion etching (RIE), deep reactive ion etching (DRIE), helicon (MORI) high-density plasma source, plasma, and chemical, e.g., Xenon Difluoride (XeF 2 ), may be used. Likewise, all known and future developed etch chemicals may be used for the wet etching process.
[0032] After each via 360 is formed to pass entirely through the thermal insulation layer 330 , the via 360 is optionally filled with a thermally conductive material to create a direct thermal contact or shunt from a heat producing layer to another layer. In other words, the via 360 , upon being filled with the thermally conductive material, forms a shunt from the localized heat producing areas 314 of the microelectronic or other (e.g., optical) chip 310 to either the ambient atmosphere 340 as shown in the embodiment of FIG. 3 or to the heat sink 450 shown in the embodiment of FIG. 4 . Each via 360 may be filled with a thermally conductive material using several well known processes, such as physical vapor deposition; chemical vapor deposition, electroplating, vacuum or spin casting, and any other known or future developed filling process. Examples of physical vapor deposition include, but are not limited to sputtering, e-beam evaporation, reflow, and forcefill. Examples of chemical vapor deposition include, but are not limited to chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), metal organic chemical vapor deposition (MOCVD), atmospheric pressure chemical vapor deposition (APCVD), and molecular beam epitaxy (MBE) growth.
[0033] Each via 360 that is filled with the thermally conductive material provides direct thermal conduction from the targeted high heat producing areas 314 to the ambient atmosphere 340 or a heat sink 450 to facilitate efficient heat extraction H at a point of greatest or highest heat generation of the chip 310 .
[0034] In one embodiment, an approximately 20 to 1 to 10 to 1, i.e., 20:1 to 10:1, aspect or height-to-width ratio is used to determine the dimensions of the vias 360 . For example, for a thermal insulating layer 330 having a thickness of 1 μm, each via 360 has a diameter that is 0.05 to 0.10 μm. Likewise, for a relatively thick thermal insulating layer 330 , such as 20 μm, each via 360 has a diameter that is 1.0 to 2.0 μm. It is within the scope of the present invention to provide, for use with a thick thermal insulating layer 330 , several fabrication iterations, which produce thin insulating layers 330 and obtain vias 360 of corresponding diameter.
[0035] The direct contact provided by the via 360 filled with thermally conductive material when targeting the localized high heat producing areas 314 allows highly efficient thermal conduction to a cooling medium. Among other things, this approach overcomes the disadvantages of conventional cooling methods, which rely solely on cooling by exterior packaging or reducing thermal budget in a manner that limits chip performance. Because vias 360 provide a passive cooling technology, the use of vias 360 that directly contact a high heat producing area of the chip 310 , among other things, also overcomes the disadvantages of other active cooling approaches, by eliminating the need for any external systems.
[0036] Further, the use of vias 360 addresses the disadvantages of through-substrate heat plug technology using powder injection molding. The present invention is Complimentary Metal Oxide Silicon (CMOS)-compatible and allows high-volume, batch processing during or after chip fabrication, while simultaneously providing smaller diameter channels that permit specific targeting of the high heat producing areas 314 on the chip 310 .
[0037] The use of the vias 360 filled with thermally conductive material and in direct contact with the top surface 312 a of the components 312 having the high heat producing areas 314 , shown in FIGS. 3 and 4 , also provides a direct path, by thermal conduction, from the high heat producing areas 314 to a cooler area, e.g., ambient atmosphere 340 or a heat sink 450 , using sub-micron or micron sized vias 360 . Moreover, with the present invention, a manufacturer is able to target specific high heat producing areas 314 on the chip 310 , provide high-efficiency thermal conduction from the thermally insulated areas, obtain CMOS compatibility, and produce high throughput and batch compatibility. The present invention enables mass production at a low cost, can be implemented during or after the chip is manufactured, allows for a relaxation of thermal budgets, which permits a widening or increase in operational limits, and enables technology for next generation, three-dimensional circuits and devices.
[0038] FIG. 5 is a flow chart of a method for manufacturing the microelectronic chip 310 having a plurality of vias 360 formed therein.
[0039] In step 501 , a thermal insulation layer 330 is formed to the top surface 312 a of the microelectronic chip 310 .
[0040] In step 502 , vias 360 are formed through an entire thickness of the thermal insulating layer 330 to contact a top surface 312 a of the region of the chip 310 having the components 312 in locations of high heat production 314 a , 314 b . The vias 360 are formed so as not to contact existing or future electrical routing, or any other components of the circuitry of the chip 310 . The thermal insulation layer 330 may be dry or wet etched, micro-machined, subjected to liftoff techniques for layer patterning, and the like to form or define the vias 360 therein.
[0041] In step 503 , a thermally conductive material, such as material containing diamond, graphite, copper, aluminum, gold, silver, silicon carbide (SiC), superconducting polymers, ceramics, and the like, is deposited within each via 360 from a top surface 312 a of the components 312 to the upper surface 330 a of the thermal insulation layer 330 . The deposition may be performed during the chip manufacturing process or after the chip 310 has been produced. The thermally conductive material may be deposited in the vias 360 by physical or chemical vapor deposition, electroplating, vacuum or spin casting, and the like.
[0042] In step 504 , a heat sink 350 is thermally coupled to the upper surface 330 a of the thermal insulation layer 330 . (It should be noted that step 504 can be omitted for the embodiment of the present invention shown in FIG. 3 .)
[0043] The present invention presents the ability to target the high heat producing areas of a microelectronic chip and provide significant operational advantages over the conventional methods, such as spray cooling, by providing passive cooling. As a result, the present invention costs less to manufacture and does not require the maintenance of additional equipment. Moreover, the vias filled with thermally conductive material can be placed as needed, with higher concentrations positioned in higher heat producing areas of the chip while avoiding critical structures, such as the electrical interconnects. Also, the filled vias directly communicate with the localized heat generating areas of the chip at one end while communicating with the ambient atmosphere or a heat sink at the other end, so as to create a direct heat conduction path that allows excess heat to efficiently flow from a point of origin or generation to the atmosphere or heat sink. The chip is thus cooled more efficiently than currently known approaches. Additionally, the filled vias permit the easy extraction of heat from individual circuit components or portions thereof.
[0044] What has been described herein is an apparatus and method for extracting heat from a microelectronic chip. In the foregoing detailed description, the apparatus and method of the present invention have been described with reference to exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention. The present specification and figures are accordingly to be regarded as illustrative rather than restrictive.
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A cooling device for a microcircuit provides a direct path of thermal extraction from a high heat producing area to a cooler area. A thermal insulation layer is formed on a body having at least one component thereon that generates the high heat producing area. At least one via is formed through an entire thickness of the insulation layer and is in direct communication with the high heat producing area. Heat from the high heat producing area is channeled through each via to the cooler area, which may be ambient atmosphere or a good thermal conductor, such as a heat sink. A thermal conductive material may be deposited within the via and increase the rate of thermal extraction therethrough.
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CROSS REFERENCE TO RELATED APPLICATIONS
Not Applicable
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
MICROFICHE APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
This invention relates generally to downhole tools for use in oil and gas wellbores and methods of drilling such apparatus out of wellbores, and more particularly, to such tools having drillable components made from metallic or nonmetallic materials, such as soft steel, cast iron, engineering grade plastics and composite materials. This invention relates particularly to improvements in the initial retention of slip-elements commonly used in the setting or anchoring of downhole drillable packer and bridge plug tools in wellbores.
In the drilling or reworking of oil wells, a great variety of downhole tools are used. For example, but not by way of imitation, it is often desirable to seal tubing or other pipe in the casing of the well, such as when it is desired to pump cement or other slurry down the tubing and force the slurry out into a formation. It thus becomes necessary to seal the tubing with respect to the well casing and to prevent the fluid pressure of the slurry from lifting the tubing out of the well. Downhole tools referred to as packers and bridge plugs are designed for these general purposes and are well known in the art of producing oil and gas.
The EZ Drill SV® squeeze packer, for example, includes a set ring housing, upper slip wedge, lower slip wedge, and lower slip support made of soft cast iron. These components are mounted on a mandrel made of medium hardness cast iron. The EZ Drill® squeeze packer is similarly constructed. The Halliburton EZ Drill® bridge plug is also similar, except that it does not provide for fluid flow therethrough.
All of the above-mentioned packers are disclosed in Halliburton Services--Sales and Service Catalog No. 43, pages 2561-2562, and the bridge plug is disclosed in the same catalog on pages 2556-2557.
The EZ Drill® packer and bridge plug and the EZ Drill SV® packer are designed for fast removal from the well bore by either rotary or cable tool drilling methods. Many of the components in these drillable packing devices are locked together to prevent their spinning while being drilled, and the harder slips are grooved so that they will be broken up in small pieces. Typically, standard "tri-cone" rotary drill bits are used which are rotated at speeds of about 75 to about 120 rpm. A load of about 5,000 to about 7,000 pounds of weight is applied to the bit for initial drilling and increased as necessary to drill out the remainder of the packer or bridge plug, depending upon its size. Drill collars may be used as required for weight and bit stabilization.
Such drillable devices have worked well and provide improved operating performance at relatively high temperatures and pressures. The packers and bridge plugs mentioned above are designed to withstand pressures of about 10,000 psi (700 Kg/cm 2 ) and temperatures of about 425° F. (220° C.) after being set in the well bore. Such pressures and temperatures require using the cast iron components previously discussed.
In order to overcome the above long standing problems, the assignee of the present invention introduced to the industry a line of drillable packers and bridge plugs currently marketed by the assignee under the trademark FAS DRILL. The FAS DRILL line of tools consist of a majority of the components being made of non-metallic engineering grade plastics to greatly improve the drillability of such downhole tools. The FAS DRILL line of tools have been very successful and a number of U.S. patents have been issued to the assignee of the present invention, including U.S. Pat. No. 5,271,468 to Streich et al., U.S. Pat. No. 5,224,540 to Streich et al., U.S. Pat. No. 5,390,737 to Jacobi et al., and U.S. Pat. No. 5,540,279 to Branch et al. The preceding patents are specifically incorporated herein.
The tools described in all of the above references typically make use of metallic or non-metallic slip-elements, or slips, that are initially retained in close proximity to the mandrel but are forced outwardly away from the mandrel of the tool to engage a casing previously installed within the wellbore in which operations are to be conducted upon the tool being set. Thus, upon the tool being positioned at the desired depth, the slips are forced outwardly against the wellbore to secure the packer, or bridge plug as the case may be, so that the tool will not move relative to the casing when for example operations are being conducted for tests, to stimulate production of the well, or to plug all or a portion of the well.
It is common practice to initially restrain the slips about the mandrel with a frangible restraining member such as a steel wire usually in the case of essentially metallic tools, and a non-metallic band in the case of essentially non-metallic tools, so that the downhole tool could be transported, handled, and placed in the wellbore without the slips becoming disassociated from the tool or extending outwardly from the tool prematurely. After the tool has positioned at the desired location within the wellbore, the tool is set by a setting tool or other means that loads the tool in such a way that the slips are forced outwardly and the retaining means is broken allowing the slips to properly position themselves between the wellbore and the tool.
In the smaller sizes of the subject packers and bridge plugs, such a prior art non-metallic retaining band has not generated many if any problems. However, in the larger sizes, those exceeding approximately 7 inches (178 mm) in nominal diameter, occasional problems have been encountered during the setting of the tool with composite retaining bands breaking and pieces thereof becoming lodged between the outer face of the slips and the wellbore. The pieces of retaining band being lodged between the slips and the wellbore can then prevent one or more of the slips from effectively engaging the wellbore and properly anchoring the tool within the wellbore. Such non-effective engagement can significantly lower the ability of the tool to resist slipping longitudinally along the wellbore when the tool is subjected to fluid pressures and thereby jeopardize the success of the planned treatment or plugging of the well.
There is also a need of an improved slip retaining means, especially in the case of non-metallic downhole packers and bridge plug type tools for the slip retaining means to be easily drillable, inexpensive, and strong enough to withstand surface handling, traveling downhole, and fluid flow around the tool within the wellbore prior to the actual setting of the tool. Furthermore, the retaining means needs to consistently and reliably release the slips at a preselected load which serves to set the tool in the wellbore. If the slip-retaining means does not release the slips at a preselected load, it may not be possible to set the tool with certain setting tools that may be available at a given well.
Thus, there remains a need within art for a reliable and consistent means for retaining the slips in their initial positions yet when the tool is sufficiently loaded, will allow the slips to properly reposition themselves upon setting the tool in the wellbore.
Another object of the present invention, especially when using two or more retaining members about a group of slips, is to provide a design that allows the two members to break at approximately the same preselected tool setting load that causes the slips to be forced outward away from the tool. Typically, a 1000 pound force, or load, is selected as the force that the packing tool must be subjected to set the tool. Upon the tool being subject to the predetermined set load, the slips will cause the retaining member closest to the packer member to break and the slips will begin to pivot outwardly because the further most retaining members from the packing assembly will not yet be subjected to the requisite tensile forces causing it to break due to the design and coaction of the slips and the slip wedge. For example, when using non-metallic slips and non-metallic slip wedges as discussed in U.S. Pat. No. 5,540,279, the inside faces of the slips and outside face of the wedge have bearing surfaces that slide against each other at an angle with respect to the centerline of the tool. Thus, as the slips move outward the retaining member may not be subjected to the requisite tensile forces needed to break the member notwithstanding that the tool itself remains subjected to the predetermined setting load.
BRIEF SUMMARY OF THE INVENTION
The slip retaining system of the present invention is a method and apparatus particularly suitable for tools having a center mandrel, a plurality of slip segments disposed in an initial position around the mandrel and requiring a retaining means for holding the slip segments in an initial position prior to setting the tool downhole. The subject retaining system is characterized by at least one frangible retaining band extending at least partially around the slips and at least one elastic O-ring extending at least partially around the slips. Preferably the retaining band is non-metallic and both the retaining band and the elastic O-ring reside in a common groove formed in the outer face of each slip. The groove further preferably has an L-shape due to an under cut in the groove to form a lip extending over the retaining band. Hardened inserts may be molded into the slips. The inserts may be metallic, such as hardened steel, or nonmetallic, such as a ceramic material.
An alternative embodiment of a rectangular shaped groove having a elastic member installed over a frangible retaining member is also disclosed.
Additional objects and advantages of the invention will become apparent as the following detailed description of the preferred embodiments is read in conjunction with the drawings which illustrate the preferred embodiment of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of representative prior art downhole packer apparatus depicting prior art slip assemblies and slip retaining elements.
FIG. 2A is a front view of a representative prior art slip segment shown in FIG. 1.
FIG. 2B is a cross-sectional side view of a representative prior art slip segment shown in FIG. 2A.
FIG. 2C is a top view of the prior art slip segments shown in FIGS. 2A and 2B.
FIG. 3A is top view of a slip wedged typically used with the prior art and with the preferred slip segment of the present invention.
FIG. 3B is a cross-sectional side view of the slip wedge of FIG. 3A.
FIG. 3C is an isolated sectional view of one of the multiple planar surfaces of the slip wedge taken along line 3C as shown in FIG. 3A.
FIG. 4A is a front view of the preferred slip having L-shaped grooves.
FIG. 4B is a side view of an embodiment of the preferred slip retaining system and further depicts the present retaining system including elastic O-ring members and frangible band members installed in their respective positions within their respective L-shaped grooves.
FIG. 5 is a side view of an alternative embodiment of the present invention having a rectangular groove and an elastic O-ring member positioned on-top of a frangible retaining band.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, FIGS. 1-3 are of prior art and have been provided as a convenient background reference. The slip retention system of the present invention is quite suitable for use with the slip segments in the representative prior art tool shown in FIGS. 1-3. Therefore a description of the workings of the prior art tool and associated slips will be followed by the description of the present invention as the present invention is very adaptable to the particular prior art slips shown in FIGS. 1-3 as well as other slips not shown.
FIG. 1 is a prior art representation of a downhole tool 2 having a mandrel 4. The particular tool of FIG. 1 is referred to as a bridge plug due to the tool having a plug 6 being pinned within mandrel 4 by radially oriented pins 8. Plug 6 has a seal means 10 located between plug 6 and the internal diameter of mandrel 4 to prevent fluid flow therebetween. The overall tool structure, however, is quite adaptable to tools referred to as packers, which typically have at least one means for allowing fluid communication through the tool. Packers may therefore allow for the controlling of fluid passage through the tool by way of a one or more valve mechanisms which may be integral to the packer body or which may be externally attached to the packer body. Such valve mechanisms are not shown in the drawings of the present document. The representative tool may be deployed in wellbores having casings or other such annular structure or geometry in which the tool may be set.
Packer tool 2 includes the usage of a spacer ring 12 which is preferably secured to mandrel 4 by pins 14. Spacer ring 12 provides an abutment which serves to axially retain slip segments 18 which are positioned circumferentially about mandrel 4. Slip retaining bands 16 serve to radially retain slips 18 in an initial circumferential position about mandrel 4 as well as slip wedge 20. Bands 16 are made of a steel wire, a plastic material, or a composite material having the requisite characteristics of having sufficient strength to hold the slips in place prior to actually setting the tool and to be easily drillable when the tool is to be removed from the wellbore. Preferably bands 16 are inexpensive and easily installed about slip segments 18. Slip wedge 20 is initially positioned in a slidable relationship to, and partially underneath slip segments 18 as shown in FIG. 1. Slip wedge 20 is shown pinned into place by pins 22. The preferred designs of slip segments 18 and co-acting slip wedges 20 will be described in more detail herein.
Located below slip wedge 20 is at least one packer element, and as shown in FIG. 1, a packer element assembly 28 consisting of three expandable elements positioned about mandrel 4. At both ends of packer element assembly 28 are packer shoes 26 which provide axial support to respective ends of packer element assembly 28. Backup rings 24 which reside against respective upper and lower slip wedges 20 provide structural support to packer shoes 26 when the tool is set within a wellbore. The particular packer element arrangement show in FIG. 1 is merely representative as there are several packer element arrangements known and used within the art but.
Located below lower slip wedge 20 are a plurality of multiple slip segments 18 having at least one retaining band 16 secured thereabout as described earlier.
At the lowermost terminating portion of tool 2 referenced as numeral 30 is an angled portion referred to as a mule-shoe which is secured to mandrel 4 by radially oriented pins 32. However lowermost portion 30 need not be a mule shoe but could be any type of section which serves to terminate the structure of the tool or serves to be a connector for connecting the tool with other tools, a valve, or tubing etc. It should be appreciated by those in the art, that pins 8, 14, 16, 22, and 32, if used at all, are preselected to have shear strengths that allow for the tool be set and to be deployed and to withstand the forces expected to be encountered in a wellbore during the operation of the tool.
Referring now to FIGS. 2-3 of the drawings. It is not necessary to have the particular slip segment and slip wedge construction shown in FIGS. 2-4 in order to practice the present invention, as the disclosed slip retention system can be used in connection with any type of downhole tool employing slips that are forced outwardly away from the tool and it does not matter whether or not the tool is made essentially of only metallic components, non-metallic components, or a combination of metallic and non-metallic components.
Slip segment 18 as shown in a front view of the slip segment, denoted as FIG. 2A, has an outer external face 19 having a plurality of inserts 34 that have been molded into, or otherwise secured into, face 19. Optional inserts 34 are typically made of zirconia ceramic which have been found to be particularly suitable for a wide variety of applications. Slip segment 18 can be made of a composite material obtained from General Plastics as referenced herein in addition to the materials set forth in the present Assignee's patents referenced herein or it can be cast iron.
FIG. 2B is a cross-sectional view taken along line 2B of slip segment of 18 FIG. 2A. Slip segment 18 has two opposing end sections 21 and 23 and has an arcuate inner mandrel surface 40 having topology which is complementary to the outer most surface of mandrel 4. Preferably end section surface 23 is angled approximately 5°, shown in FIG. 2B as angle θ, to facilitate outward movement of the slip when setting the tool. Slip segment bearing surface 38 is flat, or planar, and is specifically designed to have topology matching a complementary surface on slip wedge 20. Such matching complementary bearing surface on slip wedge 20 is designated as numeral 42 and can be viewed in FIG. 3A of the drawings. A top view of slip segment 18, having a flat, but preferably angled, top surface 23 is shown in FIG. 2C. Location and the radial positioning of sides 25 define an angle α which is preselected to achieve an optimal number of segments for a mandrel having an outside diameter of a given size and for the casing or well bore diameter in which the tool is to be set. Angle α is preferably approximately equal to 60°. However, an angle of α ranging from 45° to 60° can be used.
Returning to FIG. 2B, the sides of slip segments 18 are designated by numeral 25. It is preferred that six to eight segments encircle mandrel 4 and be retained in place prior to setting of the tool by at least one, and preferably two slip retaining bands 16 that are accommodated by circumferential grooves 36. Prior art slip retaining bands 16 are made of composite material obtained from General Plastics as referenced herein or other suitable materials such as ANSI 1018 steel wire available from a wide variety of commercial sources.
Referring to FIG. 3A, a top view is provided of preferred slip wedge 20 having flat, or planar, surfaces 42 which form an opposing sliding bearing surface to flat bearing surface 38 of respectively positioned slip segments 18. The relationship of such surfaces 38 and 42 as installed initially are best seen in FIG. 2B, FIG. 3C, and FIG. 1. As can be seen in FIG. 3C, which is a broken away sectional view taken along line 3C shown in FIG. 3A. It is preferred that slip wedge bearing surface 42 be defined by guides or barriers 44 to provide a circumferential restraint to slip segments 18 as the segments travel axially along slip wedge 20 and thus radially outwardly toward the casing or well bore during the actual setting of the packer tool. Preferably angle β, as shown in FIG. 3B is approximately 18°. However, other angles ranging from 15° to 20° can be used depending on the frictional resistance between the coacting surfaces 42 and 38 and the forces to be encountered by the slip and slip wedge when set in a well bore. Internal bore 46 is sized and configured to allow positioning and movement along the outer surface of mandrel 4.
It has been found that material such as the composites available from General Plastics are particularly suitable for making a slip wedge 20 from in order to achieve the desired results of providing an easily drillable slip assembly while being able to withstand temperatures and pressures reaching 10,000 psi (700 Kg/cm 2 ) and 425° F. (220° C.). However, any material can be used to form slips adapted to use the present slip retentions system.
A significant advantage of using such co-acting flat or planar bearing surfaces in slip segments 18 and slip wedges 20 is that as the slips and wedges slide against each other, the area of contact is maximized, or optimized, as the slip segments axially traverse the slip wedge thereby minimizing the amount of load induced stresses being experienced in the contact area of the slip/slip wedge interface. That is as the slip axially travels along the slip wedge, there is more and more contact surface area available in which to absorb the transmitted loads. This feature reduces or eliminates the possibility of the slips and wedges binding with each other before the slips have ultimately seated against the casing or wellbore. This arrangement is quite different from slips and slip cones using conical surfaces because when using conical bearing surfaces, the contact area is maximized only at one particular slip to slip-cone position. Again the present invention will work quite well with any multiple slip arrangement made of any suitable material.
Referring now to FIG. 4, which depicts a preferred embodiment of the present invention. Slip segment, or slip, 25' has the same general layout as the above discussed prior art slip 25, including outer face 19', end faces 21' and 23', mandrel surface 40', slip bearing surface 38'. Optional inserts 34' are shown in FIG. 4A but are not shown in FIG. 4B. It is contemplated that such inserts would be installed in slip 25' to provide the benefits of using such inserts to better engage the wellbore therewith.
Note that L-shaped groove 52 differs from prior art groove 36 in that L-shaped groove 52, of a preselected size, is provided with an undercut region 55 that preferably forms a protective lip 54.
Preferably, a composite frangible retaining band 56 having a preselected cross section such as a square cross section and being sized to break at a predetermined load, is first installed within undercut region 55 behind protective lip 54. Such retaining members, or bands, can be obtained from General Plastics, 5727 Ledbetter, Houston, Tx. 77087-4095. Cross-sectional profiles other than square or rectangular shapes can be used, however square or rectangular are preferred for ease of manufacture and retention characteristics. After installing band 56, an elastic nitrile rubber O-ring 58 having a durometer hardness of 90 is next installed within groove 54. As can be seen in FIG. 4A, O-ring 58 and groove 56 is sized to be accommodated by groove 54 in such a manner that O-ring 54 does not extend beyond outer face 19', and further constrains frangible retaining band member 56 within undercut region 55 and behind lip 54. Elastic member 58 need not have a circular cross-sectional profile, but such elastic members are readily available from a multitude of commercial vendors. By O-ring 58 not extending beyond face 19', O-ring 58 will not be subjected to objects or irregularities in the wellbore snagging, pulling, or otherwise damaging O-ring 58 during surface handling and downhole placement of the downhole tool in which the slip retaining system is installed. Additionally, by sizing the depth of L-shaped groove 52 and O-ring 58 so that O-ring 58 does not extend past outer face 19', the possibility of O-ring 58 being forced out of groove 52 by any fluid flowing around the packer tool as it is in the wellbore is essentially, if not completely eliminated. Thus, it is recommended that O-ring 58, or equivalent member, not be so positioned where it could be subjected unnecessarily to fluid flow induced forces within the wellbore that could damage or remove the member. By constraining frangible band member 56 behind lip 54 with elastic member 58 as taught herein, upon band 56 breaking in several places about its original circumference, the elastic member serves to somewhat restrain slips 25' in a position about slip wedge 20 while allowing slips 25' to be free enough to seek their proper set position against the wellbore. This provides an additional advantage over prior art retaining bands or wires, in that once the prior art bands were broken the slips were free to fall randomly. This could be a problem when using packer tools that are nominally much smaller than the wellbore that the packer tool is to be placed within. Thus the present invention provides a means for providing a flexible retention of the slips until the slips have reached their final position against the wellbore.
An alternative embodiment of the present retaining system is shown in FIG. 5, a rectangular shaped groove 36" dimensioned and configured to accommodate first a frangible retaining band 56" and then second an elastic O-ring 58" positioned on top of retaining band 56". The lack of a L-shaped groove does not offer the same protection of the retaining band nor does it offer the same amount of freedom for the retaining band to move about within the confines of the elastic band and the back of the groove as does the preferred embodiment. Again it is preferred that the O-ring be flush with face 19" to prevent snagging or undue exposure to fluidic forces. The other features of the depicted slip segment are the same as those discussed previously and are appropriately labeled with a double prime mark.
The alternative embodiment offers many of the other benefits of the preferred embodiment such as the constrainment of the retaining band upon it ultimately being broken while allowing a more simple to construct groove. In a yet further alternative embodiment the frangible retaining band of the present invention could be eliminated entirely and a stronger elastic O-ring, or other elastic member, be set in a groove to retain the slips until the tool is subjected to enough of a force, or load, to set the tool. Such a embodiment does not offer the redundancy of having a separate elastic member and a separate frangible member and care would have to be exercised not to provide a single elastic member that was so strong that the slips could not fully and properly be forced outwardly toward the wellbore upon being set.
A composite packer having a nominal seven (7) inch (17.8 cm) diameter was constructed to have two sets of slips of eight slips per set about the tool. Each slip had an upper L-groove and lower L-groove as shown in FIGS. 4A and 4B. The L-groove was 0.140 inches (3.56 mm) deep, 0.210 inches (5.33 mm) tall at the back of the groove, 0.155 inches (3.94 mm) at the front thereby providing a lip of 0.055 inches (1.4 mm), or in other words an undercut of 0.055 (1.4 mm) inches. A nitrile O-ring #248 having a durometer hardness 90 was used to restrain a composite retaining band having a square cross section measuring 0.050 inches (1.27 mm) per side in one groove and a like O-ring was used to retain a fiberglass composite retaining band having a rectangular cross section measuring 0.070 inches (1.78 mm) in height and 0.065 (1.65 mm)inches in width. Both retaining bands were obtained from General Plastics company. The retaining bands were cut from fiberglass-reinforced thin walled composite tube wrapped with a 1543 E-glass industrial fabric containing approximately 86% fiber by volume in wrap direction with generally available resins. The 1543 E-Glass fabric is available from Hexcel Corporation in California as well as others. Proper layup and using care in maintaining tube dimensions provided a stable retaining band tensile strength. The retaining bands were made of differing sizes in order to cause the larger band placed opposite bearing surface 38' to break at approximately the same tool load as the smaller band placed opposite mandrel surface 40'. This is based upon the differing interaction of the slips and the wedge surfaces as the slips are being forced outwardly by the wedge bearing surfaces as the tool is being set. Having differing cross sectional areas of the same retaining band material is not necessary but provides a more consistent setting of the packer tool. Of course, one could use a plurality of same sized retaining bands, and merely change the tensile strength characteristics appropriately. Furthermore merely one frangible retaining band and one elastic member per set of slips could also be used if desired.
The practical operation of downhole tools embodying the present invention, including the representative tool depicted and described herein, is conventional and thus known in the art as evidenced by prior documents.
Furthermore, although the disclosed invention has been shown and described in detail with respect to the preferred embodiment, it will be understood by those skilled in the art that various changes in the form and detail thereof may be made without departing from the spirit and scope of this invention as claimed.
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Method and apparatus particularly suitable for tools having a center mandrel, a plurality of slip segments disposed in an initial position around the mandrel and requiring a retaining means for holding the slip segments in an initial position prior to setting the tool downhole. The subject retaining system is characterized by at least one frangible retaining band extending at least partially around the slips and at least one elastic O-ring extending at least partially around the slips. Preferably the retaining band is non-metallic and both the retaining band and the elastic O-ring reside in a common groove formed in the outer face of each slip. The groove further preferably has an L-shape due to an under cut in the groove to form a lip extending over the retaining band. Hardened inserts may be molded into the slips. The inserts may be metallic, such as hardened steel, or non-metallic, such as a ceramic material.
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TECHNICAL FIELD
[0001] The present invention relates to a water treatment system.
BACKGROUND ART
[0002] When extracting oil from an oilfield, there has been carried out a so-called water flooding process, in which injection water is injected into an oil layer in the ground, and thus the oil is pushed up over the ground from the oil layer by a pressure generated in the oil layer. As oil extraction technologies with use of the water flooding process, the technologies described in Patent Documents 1 and 2 have been known.
CITATION LIST
Patent Literature
[0003] {Patent Document 1}
[0004] Japanese Patent Application Publication No. 2001-002937
[0005] {Patent Document 2}
[0006] Japanese Patent Application Publication No. 2010-270170
SUMMARY OF INVENTION
Technical Problem
[0007] During the water flooding process, water which is referred to as produced water is pushed up along with the oil from under the ground. The produced water contains various organic and inorganic substances. Therefore, it has been an urgent issue how to deal with the produced water from a viewpoint of environmental protection. Since the produced water contains heavy metals and the like, a large scale processing is necessary to release or discard the produced water in nature. Therefore, it is preferable to reuse the produced water as the injection water in order to increase an oil recovery rate.
[0008] However, the produced water as it is, is not suitable for the injection water, because it has generally a high concentration of total dissolved solids (TDS concentration: details of TDS concentration will be described later). Further, if a Reverse Osmosis membrane (RO membrane) is used in order to reduce the total dissolved solids concentration, clogging of the RO membrane is likely to occur, and there are problems such that the RO membrane cannot be easily discarded because concentrated water, which is a by-product, contains heavy metals or the like. For these points, technologies related to agents for improving oil recovery efficiency from the oil layer are described in Patent Documents 1 and 2 , however, handling or utilization of the produced water, which is produced along with oil extraction, is not disclosed.
[0009] Further, it is conceivable to use seawater, which is present in large amounts on the earth, as the injection water, in particular in areas where it is difficult to obtain fresh water. However, since many metal ions are contained in the seawater, if the seawater is used as the injection water, for example, sulfate ions react with calcium, magnesium, strontium, and the like in the ground, to produce sulfate salts in some cases. Since such sulfate salts are poorly soluble in water, when the sulfate salts are produced in the ground, clogging occurs in a pipe connecting the underground (oil layer) and the ground, and oil extraction efficiency is reduced in some cases. For seawater desalination, it is effective to reduce the sulfate ion concentration by treating with a nanofiltration membrane (NF membrane). However, it is said that use of the RO membrane is suitable for reducing not only the sulfate ion concentration but the total dissolved solids concentration.
[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a water treatment system capable of preparing the injection water from the seawater and the produced water, the injection water being capable of extracting oil without reducing oil extraction efficiency, while considering environmental protection.
Solution to Problem
[0011] As a result of intensive studies in order to solve the above problems, the present inventors have found that it is possible to solve the problems by producing injection water by mixing the produced water to the fresh water obtained by desalination of seawater.
Advantageous Effects of Invention
[0012] According to the present invention, it is possible to provide a water treatment system capable of preparing the injection water from the seawater and the produced water, the injection water being capable of extracting oil without reducing oil extraction efficiency excessively, while considering environmental protection.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 is a system diagram of a water treatment system according to a first embodiment;
[0014] FIG. 2 is a control flow in the water treatment system according to the first embodiment;
[0015] FIG. 3 is a control flow in a water treatment system according to a second embodiment;
[0016] FIG. 4 is a control flow in a water treatment system according to a third embodiment; and
[0017] FIG. 5 is a control flow in a water treatment system according to a fourth embodiment.
DESCRIPTION OF EMBODIMENTS
[0018] Hereinafter, embodiments (present embodiments) implementing the present invention will be described with reference to the drawings as appropriate.
1. First Embodiment
<Configuration>
[0019] FIG. 1 is a system diagram of a water treatment system 100 according to a first embodiment. The water treatment system 100 is configured to include four flow paths of a seawater desalination flow path A, a produced water treatment flow path B, an injection water production flow path C, and a bypass flow path D. Hereinafter, the water treatment system according to the first embodiment will be described while showing specific values, however, these values are merely an example, and the embodiment is not limited thereto.
[0020] The seawater desalination flow path A is for obtaining fresh water by desalination of seawater. The fresh water which is obtained through the seawater desalination flow path A becomes a part of injection water to be described later. A flow rate of the seawater to be supplied to the seawater desalination flow path A is 50,000 barrels/day (1 barrel is about 159 1). Further, in the first embodiment, total dissolved solids concentration in the seawater is 35,000 mg/L, and sulfate salt concentration is 3,000 mg/L.
[0021] Note that, in this specification, “total dissolved solids (Total Dissolved Solids; TDS)” refers to metal salts which are contained in the seawater, produced water, or the like. Such metal salts are, for example, sulfate salts or metal chlorides. The metal salts are ionized into minus ions (for example, sulfate ions or chloride ions) and metal ions (for example, magnesium ions or sodium ions) constituting the metal salts, to be dissolved in the seawater, the produced water, or the like.
[0022] The seawater desalination flow path A is provided with a filter device 1 for removing foreign matter by filtering the seawater, a water tank 2 for storing the seawater after removing the foreign matter, and a reverse osmosis membrane 3 (seawater desalination device) for desalination of seawater. Further, the seawater desalination flow path A is provided with pumps 4 , 6 for feeding the seawater which flows through the flow path, and a valve 5 for adjusting an amount of the seawater to be supplied to the filter device 1 based on a water level in the water tank 2 .
[0023] The filter device 1 is, for example, a sand filtration device (multimedia filter (MMF)). By this device, the foreign matter (dust or the like) in the seawater is removed, and clear seawater is supplied to the water tank 2 .
[0024] The water tank 2 is for storing the seawater which is clarified by the filter device 1 . The water tank 2 is provided with a water level sensor (not shown) for measuring the water level in the water tank 2 . An opening degree of the valve 5 is controlled so that the water level in the water tank 2 is constant, and excess seawater is returned to the ocean through the valve 5 . Note that, in addition to the seawater flowing through the filter device 1 , seawater returned from the bypass flow path D to be described later is also supplied to the water tank 2 .
[0025] The reverse osmosis membrane 3 is for obtaining fresh water by permeation of the seawater from the water tank 2 while applying pressure to the seawater. That is, in the first embodiment, on a downstream side of the reverse osmosis membrane 3 , a fresh water flow path through which the fresh water flows is formed. In the reverse osmosis membrane 3 , in addition to obtaining fresh water, a concentrated water in which ions or the like are concentrated is produced, and the concentrated water is returned to the ocean. By flowing through the reverse osmosis membrane 3 , the TDS and the like contained in the seawater are removed, and the obtained fresh water flows through the injection water production flow path C to be described later.
[0026] In the first embodiment, out of the seawater of 50,000 barrels/day which is supplied to the seawater desalination flow path A, the seawater of 40,000 barrels/day is supplied to the reverse osmosis membrane 3 . Then, in the reverse osmosis membrane 3 , out of the seawater of 40,000 barrels/day which is supplied thereto, the fresh water of 16,000 barrels/day and the concentrated water of 24,000 barrels/day are produced. Further, the remaining seawater of 10,000 barrels/day, which is not supplied to the reverse osmosis membrane 3 , is supplied to the produced water treatment flow path B through the bypass flow path D, although the details will be described later.
[0027] The produced water treatment flow path B is for obtaining treated water by removing oil contained in the produced water from an oilfield. In the first embodiment, a flow rate of the produced water to be supplied to the produced water treatment flow path B is 10,000 barrels/day. Further, in the first embodiment, the total dissolved solids concentration in the produced water is 100,000 mg/L, and the sulfate salt concentration is 1,500 mg/L. Furthermore, an amount of oil contained in the produced water is 1,000 mg/L or less, and a total solids content (Solids State; SS) is 300 mg/L or less.
[0028] The produced water treatment flow path B is provided with an oil-water separator 10 for removing oil contained in the produced water from the oilfield, and a microfiltration membrane (microfilter) 11 for filtering the treated water which is obtained by removing oil.
[0029] Further, the produced water treatment flow path B is provided with a valve 12 for adjusting the flow rate of the produced water, a pump 13 for feeding the treated water which flows through the flow path, an ion concentration sensor 14 (treated water ion concentration sensor) for measuring an ion concentration C 1 in the treated water, and a flow rate sensor 15 (treated water flow rate sensor) for measuring a flow rate Q 1 of the treated water.
[0030] The oil-water separator 10 is for obtaining the treated water by removing oil from the produced water. That is, in the first embodiment, on a downstream side of the oil-water separator 10 , a treated water flow path through which the treated water flows is formed. The oil-water separator 10 is, for example, a flocculation magnetic separator, a pressurized dissolved air flotation device, an induced gas flotation (IGF) separator, a compact flotation unit (CFU), or the like. However, in the first embodiment, the flocculation magnetic separator is used. By using this, it is possible to remove oil from the produced water more efficiently, thereby reducing a load of the microfiltration membrane 11 to be described later. Specifically, an amount of oil in the treated water which is obtained through the oil-water separator 10 is reduced to 5 mg/L or less. Since the oil, which is removed from the oil-water separator 10 , has a floc shape containing water, after dehydration using a dehydrator such as a centrifuge, a screw press, a belt press, or the like (although they are not shown), the oil is treated by drying and incineration, landfill, or the like.
[0031] The microfiltration membrane 11 is for removing a solid content in the treated water. Therefore, since the treated water is permeated through the microfiltration membrane 11 , the solid content in the treated water is removed. Specifically, in the first embodiment, the total solids content in the treated water after permeation through the microfiltration membrane 11 is 0.2 mg/L or less.
[0032] Note that, although details will be described later, to the treated water (10,000 barrels/day) which is obtained through the oil-water separator 10 , the seawater (10,000 barrels/day as described above) flowing through the seawater desalination flow path A is mixed through the bypass flow path D. Therefore, the TDS (including sulfate salts) in the treated water is diluted. Specifically, in the first embodiment, the TDS in the treated water after permeation through the microfiltration membrane 11 , that is, the TDS in the treated water which is mixed to the injection water production flow path C, is 67,500 mg/L, and the sulfate salt concentration out of this is 2,250 mg/L.
[0033] The ion concentration sensor 14 is for measuring the ion concentration C 1 of the treated water. In the first embodiment, at least one of TDS concentration, calcium ion concentration, magnesium ion concentration, and sulfate ion concentration is measured. Here, water quality variation of the produced water occurs over a relatively long time in many cases. Therefore, usually, responsiveness is not required in the measurement. Thus, for convenience of illustration, the ion sensor 14 is provided so as to be inline measurable in FIG. 1 , however, as for calcium ion, magnesium ion, and sulfate ion, it is assumed that analysis is carried out separately by obtaining the treated water at a position of the ion concentration sensor 14 .
[0034] The flow rate sensor 15 is for measuring the flow rate of the treated water which is obtained through the oil-water separator 10 . The ion concentration sensor 14 and the flow rate sensor 15 are connected to an arithmetic and control unit 50 through electrical signal lines shown by dashed lines in FIG. 1 . The arithmetic and control unit 50 will be described later.
[0035] The injection water production flow path C is for preparing the injection water for promoting oil extraction by injecting the produced water to the oilfield from which the produced water is pumped up. Specifically, in the injection water production flow path C, to the fresh water (12,000 barrels/day) which is obtained through the seawater desalination flow path A, the treated water (20,000 barrels/day) through the microfiltration membrane 11 is mixed (merged in the flow path C), and thus the injection water (32,000 barrels/day) is obtained. Note that, in the first embodiment, the TDS concentration of the injection water which is obtained through the injection water production flow path C is 37,500 mg/L, and the sulfate salt concentration out of this is 1,250 mg/L.
[0036] The injection water production flow path C is provided with an ion concentration sensor 7 (injection water ion concentration sensor) for measuring an ion concentration Ct of the injection water, and a flow rate sensor 8 (an injection water flow rate sensor) for measuring a flow rate Qt of the injection water. The ion concentration sensor 7 is for measuring ion concentration in the injection water in the same manner with the ion concentration sensor 14 . Since a measurement method and ions as measurement objects by the ion concentration sensor 7 are the same as the ion concentration sensor 14 , the description will be omitted.
[0037] Further, the ion concentration sensor 7 and the flow rate sensor 8 are connected to the arithmetic and control unit 50 through electrical signal lines shown by dashed lines in FIG. 1 . The arithmetic and control unit 50 will be described later.
[0038] The bypass flow path D is for mixing at least a part of the seawater, which flows through the seawater desalination flow path A, to the treated water which flows through the produced water treatment flow path B. The bypass flow path D is provided with a pump 21 for feeding the seawater, and a return valve 30 for controlling a flow rate Qm of the seawater to be supplied to the produced water treatment flow path B. Further, the bypass flow path D is provided with an ion concentration sensor 20 (a bypass flow path ion concentration sensor) for measuring an ion concentration Cm of the seawater to be supplied to the produced water treatment flow path B. Since a measurement method and ions as measurement objects by the ion concentration sensor 20 are the same as the ion concentration sensor 14 , the description will be omitted.
[0039] The return valve 30 is for returning the seawater, which is obtained from the seawater desalination flow path A, to the water tank 2 which is provided in the seawater desalination flow path A. That is, when the flow rate Qm of the seawater which is fed by the pump 21 is greater than a desired flow rate, a part of the seawater is returned to the water tank 2 by increasing an opening degree of the valve 30 . In the first embodiment, the flow rate of the seawater which is fed by the pump 21 is constant, and the flow rate of the seawater which is supplied to the produced water treatment flow path B is controlled by adjusting the opening degree of the return valve 30 . Therefore, in the first embodiment, a correlation (calibration curve, table, or the like) between the opening degree of the return valve 30 and the flow rate Qm of the seawater, which is supplied to the produced water treatment flow path B, is recorded in the arithmetic and control unit 50 . Then, the arithmetic and control unit 50 is adapted to adjust the opening degree of the return valve 30 based on the recorded correlation, so that the flow rate Qm of the seawater to be supplied becomes the desired flow rate, although the details will be described later. Note that, in the above example, the seawater flowing through the bypass flow path D is mixed to the treated water flowing through the produced water treatment flow path B, however, if the seawater is not necessary to flow through the microfiltration membrane 11 , the bypass flow path D may be connected to an outlet side flow path of the microfiltration membrane 11 . In this case, there is an effect that can reduce the load of the microfiltration membrane 11 .
[0040] The arithmetic and control unit 50 is for determining the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B, based on the ion concentrations Ct, C 1 , Cm measured by the ion concentration sensors 7 , 14 , 20 , and the flow rates Qt, Q 1 measured by the flow rate sensors 8 , 15 . Further, the arithmetic and control unit 50 is also adapted to adjust the opening degree of the return valve 30 so that the flow rate of the seawater becomes the determined flow rate Qm. A specific control method of the opening degree of the return valve 30 will be described later in a section of <Operation>.
[0041] Incidentally, the arithmetic and control unit 50 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a HDD (Hard Disk Drive), I/F (Interfaces), and the like, although they are not shown, and is implemented by executing a predetermined control program stored in the ROM by the CPU.
<Operation>
[0042] Next, a control in the water treatment system 100 will be described.
[0043] In the water treatment system 100 , for example, because of time degradation of the reverse osmosis membrane 3 or the oil-water separator 10 , the ion concentration C 1 and the flow rate Q 1 of the treated water which is obtained by passing through the oil-water separator 10 , and an ion concentration Cr and a flow rate Qr of the fresh water which is obtained by permeation through the reverse osmosis membrane 3 , are varied in some cases. As a result, the ion concentration Ct and the flow rate Qt of the injection water, which is produced by mixing the treated water and the fresh water, vary from conditions during a test operation of the water treatment system 100 in some cases. Therefore, in the first embodiment, by controlling the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B based on several parameters, it is possible to prevent the ion concentration Ct and the flow rate Qt of the injection water from varying significantly. Specifically, the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B is determined and controlled based on the flow rate Q 1 of the treated water, the ion concentration C 1 of the treated water, the flow rate Qt of the injection water, the ion concentration Ct of the injection water, and the ion concentration Cm of the seawater to be supplied to the produced water treatment flow path B. First, a method for determining the flow rate Qm will be described in the following.
[0044] First, as described above, it is assumed that the ion concentration measured by the ion concentration sensor 7 is Ct, the flow rate measured by the flow rate sensor 8 is Qt, the ion concentration measured by the ion concentration sensor 14 is C 1 , and the flow rate measured by the flow rate sensor 15 is Q 1 . Further, if it is assumed that the flow rate and the ion concentration of the fresh water, which is obtained by permeation through the reverse osmosis membrane 3 , are respectively Qr and Cr, a following formula (1) is derived based on the law of conservation of mass.
[0000] Q 1 ·C 1 +Qm·Cm+Qr·Cr=Qt·Ct
[0000] Qm =( Qt·Ct−Q 1 ·C 1 −Qr·Cr )/ Cm formula (1)
[0045] Here, since the ion concentration Cr of the fresh water is almost equal to 0, if Cr is assumed to be 0, a following formula (2) is obtained.
[0000] Qm =( Qt·Ct−Q 1 ·C 1)/ Cm formula (2)
[0046] By substituting the flow rates Qt, Q 1 measured by the flow rate sensors 8 , 15 , and the ion concentrations Ct, C 1 , Cm measured by the ion concentration sensors 7 , 14 , 20 in the formula (2), the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B can be calculated.
[0047] Hereinafter, a specific control flow of the flow rate Qm in the water treatment system 100 according to the first embodiment will be described with reference to FIG. 2 .
[0048] FIG. 2 is a control flow in the water treatment system 100 according to the first embodiment. The control flow shown in FIG. 2 is carried out by the arithmetic and control unit 50 . First, the arithmetic and control unit 50 measures the flow rate Qt with use of the flow rate sensor 8 , and the flow rate Q 1 of the treated water with use of the flow rate sensor 15 (Step S 101 ). The measured flow rates Qt, Q 1 are obtained by the arithmetic and control unit 50 . Next, the arithmetic and control unit 50 measures the ion concentration Ct of the injection water with use of the ion concentration sensor 7 , the ion concentration C 1 of the treated water with use of the ion concentration sensor 14 , and the ion concentration Cm of the seawater flowing through the bypass flow path D with use of the ion concentration sensor 20 (Step S 102 ). The measured ion concentrations Ct, C 1 , and Cm are obtained by the arithmetic and control unit 50 .
[0049] Next, the arithmetic and control unit 50 determines the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B through the bypass flow path D (Step S 103 ). Specifically, in the first embodiment, the arithmetic and control unit 50 determines the flow rate Qm by substituting measured values of the five parameters in the formula ( 2 ). And, the arithmetic and control unit 50 determines the opening degree of the return valve 30 from the determined flow rate Qm based on the correlation, which is stored in advance, between the opening degree of the return valve 30 and the flow rate Qm (Step S 104 ). Then, the arithmetic and control unit 50 controls the opening degree of the return valve 30 so as to be the determined opening degree (Step S 105 ). As a result, the seawater of the flow rate Qm, which is determined in Step S 103 , is supplied to the produced water treatment flow path B.
<Effects>
[0050] According to the first embodiment, even if the ion concentration C 1 and the flow rate Q 1 of the treated water, which is obtained by passing through the oil-water separator 10 , and the flow rate and the like of the fresh water, which is obtained by permeation through the reverse osmosis membrane 3 are, for example, varied because of time degradation of various devices, it is possible to prevent the ion concentration Ct and the flow rate Qt of the injection water from varying significantly. Therefore, it is possible to prepare the injection water capable of stably extracting oil without significant variation of injection water conditions which are set in advance and suitable for oil extraction.
[0051] Here, the treated water contains a large amount of TDS (salt). Although the injection water preferably contains a certain amount of salt in order to improve oil extraction efficiency, excessive salt reduces oil extraction efficiency in some cases.
[0052] Therefore, it is difficult to use the produced water or the treated water as it is as the injection water.
[0053] Further, even if it is intended that the treated water is, for example, desalinated by a reverse osmosis membrane, it is difficult to desalinate the treated water by the reverse osmosis membrane, because the produced water contains a very large amount of salt. Further, since various substances other than oil are also contained in the produced water, if the produced water is supplied to the reverse osmosis membrane, there is a possibility that a degradation rate of the reverse osmosis membrane is accelerated. Therefore, it is usually difficult to use the produced water as the injection water. Furthermore, even if the produced water can be desalinated by the reverse osmosis or the like, a concentrated water to be produced contains various ions and the like. Therefore, there is a possibility that the concentrated water cannot be released to the outside as it is.
[0054] In addition to these, because of the same reason as a reason why it is difficult to use the treated water as it is as the injection water, it is also difficult to use the seawater containing a large amount of salt as it is as the injection water. In particular, when the seawater is used as it is as the injection water, oil extraction efficiency is reduced in some cases, and further, sulfate ions and the like contained in the seawater and calcium, magnesium, strontium, and the like in the ground are chemically bonded, to produce poorly soluble sulfate salts in some cases. Then, by the salts, a pipe connecting the oil layer and above ground is clogged, to reduce oil extraction efficiency in some cases.
[0055] However, in the first embodiment, the treated water is produced by removing oil from the produced water, and by mixing the treated water with the fresh water obtained by desalination of seawater, the injection water is prepared. In particular, since the produced water is used to be mixed with the fresh water, it is possible to increase the flow rate of the injection water. In this manner, according to the first embodiment, the produced water can be used to prepare the injection water, although treatment of the produced water has been complicated and utilization of the produced water as the injection water has been also conventionally complicated. As a result, it is possible to reduce the produced water (including the produced water after treatment) which is discharged to the outside, and thus it is advantageous from a viewpoint of environmental protection.
[0056] Further, in the first embodiment, instead of treating all of the intaken seawater by the reverse osmosis membrane 3 , a part of the intaken seawater flows through the bypass flow path D, to be supplied to the produced water treatment flow path B. In particular, the TDS and the like are not removed by the microfiltration membrane 11 , however, as described above, it is preferable that the injection water contains a certain amount of TDS and the like. Therefore, if the concentration of the TDS and the like contained in the injection water is in a preferred range, it is not necessary to remove the TDS and the like in the seawater by desalinating all of the seawater through the reverse osmosis membrane 3 . Since the reverse osmosis membrane 3 is more elaborate than the microfiltration membrane 11 , it is possible to reduce the degradation rate of the reverse osmosis membrane 3 by reducing the amount of the seawater to be supplied to the reverse osmosis membrane 3 . As a result, it is possible to reduce replacement frequency of the reverse osmosis membrane 3 , thereby reducing cost.
2. Second Embodiment
[0057] A water treatment system according to a second embodiment has basically the same device configuration as the water treatment system 100 according to the first embodiment. However, in the second embodiment, a control which is different from that of the first embodiment is performed. Therefore, description of the device configuration is omitted, and the second embodiment will be described focusing on the control performed in the second embodiment.
[0058] In the first embodiment, the control is performed based on five measured values. However, the water treatment system 100 is operated at a constant flow rate of the produced water (that is, a constant flow rate Q 1 of the treated water to be obtained) in some cases. Further, the ion concentration (C 1 ; measured by the ion concentration sensor 14 ) of the produced water and the ion concentration Cm of the seawater do not usually vary significantly. Therefore, as a simpler control, by assuming that these parameters are constants (values measured during test operation) in the formula (2), it is possible to determine the flow rate Qm of the seawater flowing through the bypass flow path D based on the ion concentration Ct and the flow rate Qt of the injection water. In other words, the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B can be calculated based on the following formula (3) which is obtained by modifying the formula (2).
[0000] Qm =( Qt·Ct−Q 1 C 1)/ Cm=Qt·Ct/Cm−Q 1 C 1 /Cm=a·Qt·Ct−b formula (3)
[0059] Here, a and b are constants.
[0060] FIG. 3 is a control flow in the water treatment system according to the second embodiment. In FIG. 3 , the same steps as the flow shown in FIG. 2 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. The control flow shown in FIG. 3 is carried out by the arithmetic and control unit 50 .
[0061] First, the arithmetic and control unit 50 measures the flow rate Qt of the injection water by the flow rate sensor 8 (Step S 201 ). Further, the arithmetic and control unit 50 measures the ion concentration Ct of the injection water by the ion concentration sensor 7
[0062] (Step S 202 ). And, by substituting the two measured values in the formula ( 3 ), the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B is determined (Step S 103 ). Then, in the same manner as the first embodiment, the opening degree of the return valve 30 is controlled (Steps S 104 and S 105 ). As a result, the seawater of the flow rate Qm, which is determined in Step S 103 , is supplied to the produced water treatment flow path B.
[0063] By controlling the water treatment system by using the formula (3), variables are two, and thus a simple control can be carried out. In particular, water quality (ion concentration and the like) of the produced water and the seawater does not vary significantly, or varies slowly over a relatively long time even if it varies. Therefore, by determining the flow rate Qm by assuming that the flow rate of the produced water (that is, the flow rate Q 1 of the treated water), the ion concentration of the produced water (that is, the ion concentration C 1 of the treated water), and the ion concentration Cm of the seawater are constants, the control can be simplified while having a sufficient accuracy similarly to the first embodiment.
[0064] Note that, in an example described above, the water treatment system is controlled by measuring the ion concentration Ct and the flow rate Qt of the injection water, however, it can also be controlled based on only either one as a more simplified control. For example, if the flow rate of the seawater and the flow rate of the produced water to be taken in the water treatment system 100 are constant, the flow rate Qt of the injection water is also usually constant. Therefore, in addition to the above three parameters, by assuming that the flow rate Qt of the injection water is also a constant, it is possible to determine the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B based on the ion concentration Ct of the injection water. Further, for example, if the flow rate of the treated water obtained in treatment by the oil-water separator 10 varies significantly, the flow rate of the injection water is also likely to vary significantly. Therefore, in this case, by assuming that the ion concentration Ct of the injection water is a constant, it is possible to determine the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B based on the flow rate Qt of the injection water.
3. Third Embodiment
[0065] As described above, from a viewpoint of good oil extraction efficiency, it is found that the injection water has a preferred range of concentration of each ion (TDS, sulfate ion, calcium ion, magnesium ion, or the like) contained therein. Further, since the oil in the oil layer decreases as an amount of extracted oil increases, it is preferable to increase an amount of the injection water. Therefore, even if the ion concentration of the injection water is the same, it is sometimes desired to increase the amount of the injection water to be prepared.
[0066] Therefore, in the first embodiment or the like, the control for suppressing condition variations of the injection water accompanying to the time degradation or the like has been described, however, in the third embodiment, a control capable of preparing the injection water having desired conditions (the ion concentration Ct and the flow rate Qt) will be described. Note that, since a device configuration of a water treatment system 100 is the same as that of the first embodiment shown in FIG. 1 , its description and illustration will be omitted.
[0067] Further, the TDS in the injection water varies depending on geological formation of the oilfield, however, the TDS is, for example, more than or equal to 1,000 mg/L and less than or equal to 100,000 mg/L, and preferably more than or equal to 1,000 mg/L and less than or equal to 40,000 mg/L. Therefore, in the third embodiment, it is assumed that the TDS in the injection water to be prepared can be controlled to be in this range. In particular, there is cited a case in which an ion concentration set value C 2 for the TDS in the injection water is 50,000 mg/L which is substantially an intermediate value in this range, so that there is no problem even if the TDS concentration varies to some extent.
[0068] FIG. 4 is a control flow in the water treatment system 100 according to the third embodiment. In FIG. 4 , the same steps as the flow shown in FIG. 2 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. The control flow shown in FIG. 4 is carried out by the arithmetic and control unit 50 .
[0069] First, the arithmetic and control unit 50 measures the two flow rates Qt, Q 1 in the same manner as Step S 101 in FIG. 2 (Step S 101 ). The measured flow rates Qt, Q 1 are obtained by the arithmetic and control unit 50 . Next, the arithmetic and control unit 50 measures the ion concentration C 1 of the treated water by the ion concentration sensor 14 , and the ion concentration Cm of the seawater by the ion concentration sensor 20 (Step S 302 ). Here, the ions to be measured by the ion concentration sensors 14 , 20 are the ions set in the preferred range for the injection water, and are the TDS in the third embodiment. The measured ion concentrations C 1 , Cm are obtained by the arithmetic and control unit 50 .
[0070] Next, the arithmetic and control unit 50 obtains the ion concentration set value C 2 , which is inputted through an input unit (not shown) by an administrator, and stored in a storage unit (not shown) (Step S 303 ). This is an alternative to the measured value of the ion concentration Ct measured by the ion concentration sensor 7 in the first embodiment.
[0071] And, by using the four measured conditions (the two flow rates Qt, Q 1 , and the two ion concentrations C 1 , Cm), and the ion concentration set value C 2 set by the administrator, the arithmetic and control unit 50 determines the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B (Step S 103 ). In this case, the ion concentration set value C 2 , which has been set, is used in place of the flow rate Ct in the formula (2). Then, in the same manner as the first embodiment, the opening degree of the return valve 30 is controlled (Steps S 104 and S 105 ). As a result, the seawater of the flow rate Qm, which is determined in Step S 103 , is supplied to the produced water treatment flow path B.
[0072] Although the five measured values are used in the first embodiment, the four measured values and one set value are used in the third embodiment. And, the flow rate Qm corresponding to this one set value is determined. In this manner, it is possible to prepare the injection water which is, for example, set to have a desired concentration of the TDS by using the seawater and the produced water. As a result, it is possible to prepare the injection water capable of having good oil extraction efficiency, thereby improving the oil extraction efficiency.
[0073] Note that, there is cited the TDS as a component in the preferred range of the ion concentration Ct in the above example, however, for example, sulfate concentration (sulfate ion concentration), calcium ion concentration, or magnesium ion concentration may be adjusted to be in a preferred range. Then, in accordance with the ions to be adjusted, kinds of the ions, which are measured by the ion concentration sensors 14 , 20 , only have to be changed. Each preferred range is not generalized because it varies depending on geological formation or the like of the oilfield, however, the calcium ion concentration of the injection water is, for example, more than or equal to 100 mg/L and less than or equal to 10,000 mg/L, and preferably more than or equal to 150 mg/L and less than or equal to 2,000 mg/L. Further, the sulfate ion concentration of the injection water is, for example, more than or equal to 10 mg/L and less than or equal to 500 mg/L, and preferably more than or equal to 10 mg/L and less than or equal to 100 mg/L, That the preferred ranges of these ions are all satisfied is in particular preferable, however, one or more of these ranges may be satisfied.
[0074] In addition, if it is desired to change the flow rate Qt while maintaining the ion concentration Ct of the injection water, in the same manner as the case of change in the ion concentration described above, a set flow rate which is a desired flow rate may be substituted in the formula (2) in place of the measured value of the flow rate Qt measured by the flow rate sensor 8 . Thus, the injection water having both of the desired flow rate Qt and the ion concentration Ct can be prepared.
[0075] As described above, the fresh water used in the preparation of the injection water can be obtained by desalination of seawater, and is water from which the TDS or the like contained in the seawater is removed. Therefore, the fresh water used in the preparation of the injection water can be obtained with any seawater desalination technology. As described above, there is a preferred range for concentration of the TDS or the like in the injection water, however, since the TDS or the like is contained in the produced water, the fresh water, which is obtained with any seawater desalination technology, can contain the TDS or the like by using the produced water, because the TDS or the like is contained in the produced water. In particular, in the third embodiment, in accordance with the ion concentration C 1 and the flow rate Q 1 of the treated water which is obtained by removing oil from the produced water, the injection water can contain an amount of ions suitable for oil extraction, and a desired amount of injection water can also be obtained.
4. Fourth Embodiment
[0076] In the second embodiment, the simplified control has been described, and in the third embodiment, the control capable of appropriately changing the conditions (the flow rate Qt and the ion concentration Ct) of the injection water to be prepared has been described. However, according to the present embodiment, a control combining these can be carried out. Therefore, in the fourth embodiment, a simplified control method capable of appropriately changing the conditions of the injection water to be prepared will be described. Note that, in the fourth embodiment, the control method will be described with a case, in which the ion concentration of the injection water is set to be the ion concentration set value C 2 similarly to the third embodiment, as an example.
[0077] FIG. 5 is a control flow in a water treatment system according to the fourth embodiment. The same steps as the flows shown in FIGS. 2 to 4 are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. The control flow shown in FIG. 5 is carried out by the arithmetic and control unit 50 .
[0078] First, in the same manner as the second embodiment, the arithmetic and control unit 50 measures the flow rate Qt of the injection water by the flow rate sensor 8 (Step S 201 ). Next, in the same manner as the third embodiment, the arithmetic and control unit 50 obtains the ion concentration set value C 2 (Step S 303 ). And, the arithmetic and control unit 50 determines the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B by using the measured flow rate Qt and the ion concentration set value C 2 which has been set (Step S 103 ). In this case, the ion concentration set value C 2 , which has been inputted, is used in place of the flow rate Ct in the formula (3). Then, in the same manner as the first embodiment, the opening degree of the return valve 30 is controlled (Steps S 104 and S 105 ). As a result, the seawater of the flow rate Qm, which is determined in Step S 103 , is supplied to the produced water treatment flow path B.
[0079] According to the fourth embodiment, as in the second embodiment and the third embodiment, the ion concentration Ct of the injection water can be a desired value by the simplified control. Further, similarly to the third embodiment, when the flow rate Qt of the injection water is intended to be a desired value, the ion concentration Ct of the injection water is measured, and the flow rate Qm of the seawater may be calculated by using the formula (3).
5. Modified Example
[0080] Hereinabove, the present embodiments have been described with some embodiments, however, the present embodiments are not limited to the above-described examples. That is, the present invention can be implemented by arbitrarily modifying the above-described embodiments in a range without departing from the spirit of the present invention.
[0081] For example, the present invention can be implemented by appropriately combining the above-described embodiments with each other. Specifically, for example, the control (the second embodiment, the fourth embodiment, or the like) may be carried out by the administrator so that the ion concentration and the flow rate of the injection water are changed as needed, while the control (the first embodiment, the third embodiment, or the like), in which the arithmetic and control unit 50 monitors the ion concentration Ct and the flow rate Qt of the injection water always or at predetermined intervals so that these values do not change significantly, is carried out.
[0082] Further, for example, in each of the embodiments described above ( FIG. 1 ), the seawater desalination flow path A is provided with the seawater desalination device (reverse osmosis membrane 3 ), and the produced water treatment flow path B is provided with the oil-water separator 10 . In other words, in each of the embodiments described above, the seawater desalination flow path A is configured to include the flow path through which the seawater flows, the reverse osmosis membrane 3 , and the flow path (fresh water flow path) through which the fresh water flows. Further, the produced water treatment flow path B is configured to include the flow path through which the produced water flows, the oil-water separator 10 , and the flow path (treated water flow path) through which the treated water flows. However, if the flow path (fresh water flow path) through which the fresh water flows from the seawater desalination device is provided, there is no need that the seawater desalination device or the like is necessarily provided. Similarly, if the flow path (treated water flow path) through which the treated water flows from the oil-water separator is provided, there is no need that the oil-water separator or the like is necessarily provided.
[0083] Further, for example, in each of the embodiments described above ( FIG. 1 ), at least a part of the seawater flowing through the seawater desalination flow path A in FIG. 1 is supplied to the treated water flowing through the produced water treatment flow path B. However, the seawater to be supplied to the treated water may not necessarily be the seawater flowing through the seawater desalination flow path A in FIG. 1 . Specifically, for example, the seawater may be taken in a system different from the system shown in the water treatment system 100 in FIG. 1 , and the seawater which is taken may be supplied to the treated water flowing through the produced water treatment flow path B.
[0084] Further, for example, in the water treatment system 100 shown in FIG. 1 , the flow rate of the seawater flowing through the bypass flow path D is changed by adjusting the opening degree of the return valve 30 , however, in place of the return valve 30 and the pump 21 , an inverter control pump may be provided in the bypass flow path D. Thus, by changing a rotational frequency of the pump, the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B can be changed. Further, by providing a valve capable of appropriately adjusting the flow rate in the bypath flow path D in place of the return valve 30 , and by adjusting an opening degree of the valve, the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B may be controlled.
[0085] Further, for example, in the above-described embodiments, each of four ion concentrations (TDS concentration, calcium ion concentration, magnesium ion concentration, and sulfate ion concentration) are measured by each ion concentration sensor, however, one to three kinds of these ion concentrations may be measured. In other words, in accordance with ions (which can be measured by the ion concentration sensor 7 ) contained in the injection water, the kind of the ions, which are measured by the other sensors, only have to be determined. Further, there is no need that the ion concentration sensors are necessarily inline sensors, and by providing sampling ports in place of the concentration sensors 7 , 14 , 20 , ion concentrations in liquids, which are sampled through the sampling ports, may be measured at a separate place (chemical laboratory or the like).
[0086] Further, for example, there is no need that the seawater desalination device provided in the water treatment system 100 is necessarily the reverse osmosis membrane which is illustrated. Therefore, if it is a device capable of desalinating the seawater, it is not limited to the reverse osmosis membrane, and any device can be used. Further, in order to efficiently perform reduction of the sulfate ion concentration and reduction of the TDS concentration at the same time, a nanofiltration membrane and the reverse osmosis membrane may be provided in parallel, or three kinds of membranes of the microfiltration membrane (MF membrane), the nanofiltration membrane, and the reverse osmosis membrane may be provided in parallel. Further, the filter device 1 , the water tank 2 , the microfiltration membrane 11 , and the like are not essential devices, and they may not be provided as needed. Furthermore, alternate devices having similar operations can be provided.
[0087] Further, for example, in each of the embodiments described above, the flow rate Qm of the seawater to be supplied to the produced water treatment flow path B from the seawater desalination flow path A is determined by using the formula (2) or the formula (3). However, a specific determination method of the flow rate Qm is not limited thereto. Therefore, it is preferred that the flow rate Qm is determined based on at least one of the ion concentration and the flow rate (both are concepts including both a measured value and a set value) of the injection water, however, the flow rate Qm may be determined by any method.
[0088] As described above, according to the present invention, it is possible to provide a water treatment system capable of preparing the injection water from the seawater and the produced water, the injection water being capable of extracting oil without reducing oil extraction efficiency, while considering environmental protection.
REFERENCE SIGNS LIST
[0089] 3 : reverse osmosis membrane (seawater desalination device)
[0090] 7 : ion concentration sensor (injection water ion concentration sensor)
[0091] 8 : flow rate sensor (injection water flow rate sensor)
[0092] 10 : oil-water separator
[0093] 14 : ion concentration sensor (treated water ion concentration sensor)
[0094] 15 : flow rate sensor (treated water flow rate sensor)
[0095] 20 : ion concentration sensor (bypass flow path ion concentration sensor)
[0096] 50 : arithmetic and control unit
[0097] 100 : water treatment system
[0098] A: seawater desalination flow path (including fresh water flow path)
[0099] B: produced water treatment flow path (including treated water flow path)
[0100] C: injection water production flow path
[0101] D: bypass flow path
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Provided is a water treatment system with which it is possible for injection water suitable for drilling to be prepared from seawater and produced water, without decreasing drilling efficiency, and with consideration to environmental protection. To achieve this, the system is equipped with: a fresh water flow passage for conducting fresh water from a desalination apparatus which desalinates seawater to obtain fresh water; a treated water flow passage for conducting treated water from a water/oil separation apparatus which removes the oil component contained in the produced water from an oilfield, to obtain treated water; and an injection water preparation flow passage in which the flows of treated water conducted through the treated water flow passage and the fresh water conducted through the fresh water flow passage converge, and injection water for injection into the oilfield is prepared.
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This is a division of application Ser. No. 320,599, filed on Nov. 12, 1981, now U.S. Pat. No. 4,433,443.
BACKGROUND OF THE INVENTION
Marine sanitary devices in particular and waste disposal systems in general have been proceeding through an evolutionary process for a number of years. The Environmental Protection Agency (EPA) has issued various specifications regarding requirements for processing liquid and solid human waste as set forth in 33 C.F.R. 159. Sewage of waste disposal basically requires that, under certain circumstances, substantially all of the solid waste must be removed from any liquid discharged from the vessel. An additional requirement of EPA is to reduce fecal coliform bacteria to less than 200 count per 100 milliliters. In many instances recirculation of the fluid, for example water is desirable.
Separation of solid waste and collection can be accomplished in a variety of different well known manners. The difficulty resides in storage and disposal. Clearly improvements in this area are necessary particularly when stringent EPA sanitary regulations are taken into considerations and criteria such as size, cost and efficiency of operation are kept in mind.
Several effective systems are disclosed in commonly owned U.S. Pat. No. 4,393,524 and U.S. Pat. No. 4,519,103.
In addition to the factors taken in consideration in development of those systems, other factors also must be frequently considered. For example, in certain restricting and confined environments, storage of fluid such as water for use in the waste disposal system becomes burdensome and difficult. It would also be advantageous to minimize this difficulty whenever possible, for example, in geographic areas where a large volume of water is immediately and directly available, such as in marine environments like an ocean or a salt water lake. Accordingly, a system that would be designed to draw water directly from the external environment for use during a waste disposal sequence and then to discharge the water from the system back into the environment as acceptable effluent under EPA regulations would be extremely desirable. Elimination of a reservoir would reduce the size of the system and make it attractive to marine vessels where space is at a premium. With this same thought in mind, it would be helpful if the system could be designed in a modular fashion with many of the components designed as part of readily replaceable modules either for disposal of waste or replacement of components.
SUMMARY OF THE INVENTION
With the above background in mind, it is among the primary objectives of the present invention to provide a system for processing liquid and solid human waste in a manner consistent with stringent requirements of the EPA. The system includes a self-contained unit including a removable module disposable filter cassette designed to achieve "white glove" servicing of the system. The system is compact and the cassette can be interconnected with a toilet bowl and packaged beneath the bowl in a space saving arrangement which is particularly useful in confined areas, for example in marine use. Additionally, other components of the system are also formed in a compact and modular nature for space saving advantages as well as ease of maintenance. The system of the present invention is designed for use as a flow through system where virtually no fluid volume is retained within the system between uses. It is adapted for connection to an external source such as a salt water body and when actuated will immediately draw the salt water into the system during the waste disposal sequence for a relatively rapid and efficient time and operational sequence. At the end of that sequence, the salt water which now contains waste material is discharged from the system as effluent fluid. A predetermined amount of clean water from the water source is retained in the bowl between uses in preparation for the next use. The design of this system is such that, with the use of external salt water, a minimum number of components are required for the waste disposal treatment sequence and any difficulties encountered in storing treated fluid within the system are eliminated.
It is an objective of the present invention to provide a modular system whereby the filter cassette within the system can be used for efficient storage of solid waste and then removed and replaced when full. Other portions of the system are modular and compact so that they can be readily replaced for maintenance purposes.
An objective is to provide a compact inexpensive system utilizing low cost filtration materials to achieve minimum cost per flush. The system is energy efficient and only a small amount of electrical power is required for use.
A further objective is to provide a system in which solid waste is effectively filtered from fluid waste and the filtered fluid is thereafter retained separate from the collected solids to prevent recontamination and is further filtered and then discharged from the system as effluent. This is accomplished by a uniquely designed filter cassette and recirculation system elements.
The system of the present invention is designed with separate pumps for rinse and refill and recirculation and removal of filtered fluid from the system. The waste disposal system is unitary and self-contained with only the necessity of external fluid being introduced for the sanitation and filtering sequence and then discharged.
Danger of recontamination of the filtered fluid is eliminated since as soon as the solid waste has been collected and the fluid has been properly treated it is discharged from the system as effluent without the danger of contacting and being recontaminated by the separated solids. This is particularly useful under agitation conditions, for example, the pitch and roll encountered in a marine vessel.
The cassette is designed to roll filter material about a spindle or take-up roll assembly. Solid waste material is separated and rolled up into the take-up roll. Controls are provided to intitiate rolling of a predetermined amount of filter material onto the take-up roll after a flush sequence and indicating means is provided to denote a completion of use of the filter material in the cassette. The cassette can then be removed and replaced and the system used again in the same manner. In this way, the removed filter cassette can be disposed of in a simple, clean and efficient manner. There is no necessity to open the cassette or gain access to the interior thereof.
The configuration of the cassette is such that the filtered fluid is directed away from the separated solid waste material and is quickly and efficiently pumped from the cassette. The fluid is then recirculated through the system for a predetermined period of time for further filtering in the cassette and ultimately is discharged from the system as acceptably clean effluent.
The cassette take up roll for the filter material contained therein has a polyagonal configuration, for example triangular which facilitates directing the larger portions of the solid waste on the filter material with the material wrapping around the roll for collection and storage.
It is an objective of the invention to provide unique controls including a particular arrangement of pumps, valves and interconnected conduits to facilitate a predetermined and timed sequence of operation for the self-contained sewage waste disposal system. The system is designed so that the toilet bowl is rinsed and refilled, the flushed fluid containing solid waste is passed through a filter cassette where the solid waste is substantially entirely removed and the fluid waste is maintained separately from the solid waste and recirculated through the filtering system in the cassette for further filtration for a predetermined period of time and thereafter discharged from the system as effluent. The system is a flow-through system whereby the external fluid source, such as a salt water body, provides fluid directly to the system for the waste treatment sequence and then is disposed and discharged from the system as effluent. No untreated, partially or fully treated volume of fluid is stored within the system.
A processing module is provided as a separate module component of the system and includes a flush valve, a recirculation valve, and an effluent valve to provide the necessary fluid paths for the fluid passing through the system and a sanitizing and deodorizing unit. The sanitizing and deodorizing unit can be any one of a number of different types of units used for that purpose. For example, it can be in the form of an electrolytic cell, a unit employing ozone generation, or a unit utilizing ultra violet radiation. The sanitizing and deodorizing unit can also employ chemical disinfection. For example, a hypochlorite solution, either solid or liquid can be used. Alternatively, iodine, bromine, mecuric salt, or silver salt solutions can be used. Another type of chemical disinfection is by pH adjustment. Alternatively, the sanitation module can be one which employs heat. For example, the heat could be produced by electrical resistance, combustion or chemical reaction. With these other sanitizing methods, salt water is not needed.
The controls for operating the system can be conventional types of electrical or pneumatic controls which conveniently provide for the desired program timing and sequence of operation.
The present system is capable of being utilized in marine environments, camping sites, construction locations, mobile vehicles, and other similar places where self-contained waste disposal systems are applicable.
In summary, a self-contained sewage waste disposal system is provided including a housing structure and a toilet bowl adapted to receive human waste and fluid for diluting the waste, transporting the waste and rinsing the bowl. The system includes a removable filter cassette in the housing in communication with the toilet bowl. Means is provided for flushing the bowl and dumping the contents into the filter cassette and for subsequent refilling of the bowl. A filter in the cassette separates the particles of solid material from the fluid received from the bowl. Storage means in the cassette stores the solid material in a compact manner for subsequent disposal upon removal of the cassette. Pump means is provided including interconnected conduits in the housing to transport fluid directly from an external source to fill the bowl after a flush, to transport and recirculate filtered fluid through the system for further waste disposal treatment and to direct the effluent fluid from the system thereafter. Control means is provided to pass the fluid through the system to facilitate the collection and disposal of sewage waste within the system in a predetermined sequence.
With the above objectives among others in mind, reference is made to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In The Drawings:
FIG. 1 is a perspective view of the self-contained sewage waste disposal system of the present invention;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a top plan view therof;
FIG. 4 is a sectional side elevation view thereof;
FIG. 5 is a sectional rear elevation view thereof with arrows showing the direction of fluid flow through the system;
FIG. 6 is a top plan view of the processing module portion of the system;
FIG. 7 is a sectional side elevation view thereof;
FIG. 8 is a block diagram of the sequence of operations of the system;
FIGS. 9A and 9B is a schematic view of the electrical circuitry of the system; and
FIG. 10 is a schematic view of the functional timing sequence of the system.
DETAILED DESCRIPTION
System 20 as shown includes a compact housing structure 22 for the system components as well as providing a weight support contoured for the user. The components of system 20 are incorporated within the housing and thus it is an entirely self-contained system designed for disposal of sewage waste. In this manner, it is particularly useful in the marine environment since it will satisfy certain stringent EPA requirements for handling of human waste and alleviate the necessity of fluid storage in that it will operate with a flush cycle including the intake of salt water at the beginning of the cycle and the discharge of effluent clean salt water at the end of the flush cycle.
System 20 is shown in its entirety in FIGS. 1-5 with the basic parts of the system within housing 22. Housing 22 includes an upper housing subassembly 24 and side panels 26. The upper housing and side panels are interconnected in a suitable manner such as by bolt assemblies 27. The major ccomponents of the upper subassembly housing include a flush handle 28 mounted on the front exterior of the housing and interconnected with the electronic controls within the system to operate certain portions of the system when the flush lever is depressed. An electronic control panel, module or PCB assembly 30 is mounted in conventional fashion on the interior of the upper housing and contains the electrical controls for the system. A rinse pump 32 is mounted below control panel 30 in the upper housing by conventional means such as bracket 33 affixed to the side wall of the upper housing. An inlet tube 34 extends into the housing from the exterior thereof and communicates with the rinse pump 32. The exit end of the rinse pump 32 is interconnected with a conduit 36 in the upper housing which is in turn connected with a solenoid valve 38. The other end of the valve 38 has a tube 40 connected thereto extending into communication with a fitting 42 on toilet bowl assembly 44. The fitting 42 is in communication with a flush ring on the bowl 44 for rinse and refill purposes. A suitable arrangement of bowl brackets 46 are provided for mounting the vitreous china bowl assembly 44 within the upper housing 24. Two circuit breakers 48 and 49 are provided in the upper housing adjacent to the solenoid valve 38.
An interconnected venting arrangement to provide suitable vent means for the system is at the upper end of the upper housing assembly 24 and includes a vent hose 50 and a vent connector 52.
The upper housing assembly includes a rear access panel 54 which is removable to permit access to the contents of the interior of the upper housing assembly 24.
Also removably mounted in the upper housing assembly is a removable processing module 56. The processing module 56 is removable for ease of servicing and replacement when desired. It is removable by opening the rear access panel 54. The processing module has among its components a flush valve assembly 58 and an electrolytic cell assembly 60. The module 56 is interconnectable with a solenoid valve assembly 62 which are 2-two way valves operating as recirculation and effluent valves. This is an alternate means of flow direction replacing the valves in processing module 56. A tube 64 connects the solenoid valve assembly 62 to the processing module 56 and particularly the electrolytic cell 60 within the module. A conduit 66 connects the valve assembly 62 to the pump 68 in the lower housing enclosed by side panels 26 which in turn is connected to the filter cassette assembly 70 removably mounted in the lower housing enclosed by side panels 26. All of the tubes within the housing interconnecting the components for fluid flow are mounted to appropriate fittings in a conventional manner such as by overlying frictional interengagement and retained in that position by a suitable clamp and screw assembly 72.
The lower housing 25 holds a number of major components of the system including pump 68 and cassette assembly 70. The cassette 70 is removably interconnected with a cassette filter drive mechanism 72 which includes a sprocket drive 74 and a chain 76 interconnected therewith. A reed switch 78 is mounted on the lower housing. Chain 76 extends into interconnection with the drive shaft of a conventional drive motor 80 mounted in lower housing 25.
The replaceable cassette assembly 70 contains a filter 82, a supply roll 84 for the filter screen 82 and a take-up roll assembly 86.
A conventional seat and cover assembly 89 is mounted on bowl assembly 44.
Adjacent to flush lever 28 on the front exterior of the upper housing is a pair of indicator lights, an upper indicator light 88 indicating operation of the processing sequence when lit and a lower indicator light 90 indicating the need to change the filter cassette when lit. On the interior of the upper housing assembly is a harness 92 which interconnects the wiring to the control panel 30.
The cassette assembly 70 includes an outer housing 94 having a configuration generally which facilitates its use in occupying the least amount of space and keeping with the compact nature of the system 20. Additionally, the configuration is such that filtered fluid is isolated from the danger of contamination from separated waste solids within the cassette. The housing 94 includes an entrance opening 96 in its upper surface and a fluid disconnect 98 at its rear lower end for interconnection with a hose to pump 68 for recirculation and the further treatment and eventual removal of fluid from the system as effluent fluid.
Take-up roll assembly 86 includes a central shaft 100 and a polyagonally shaped member 102 mounted thereon to rotate therewith. In the embodiment shown, the member 102 has a triangular configuration which facilitates accumulation of solid waste and filter material as it is being accumulated on the take up roll assembly 84 for eventual disposal. Shaft 100 with interconnected sprockets is releasably interconnected with sprocket drive 74 to be rotated through the use of chain 76 by activation of drive motor 80.
The supply roll 84 containing the supply of filter material 82 has a suitable piece of magnetic material 104 thereon for use in determining when the filter roll 84 has been rotated to supply filter material and when the filter material is exhausted. The magnet or magnetic material 104 is sensed by an appropriate electrical switch in the circuitry.
A splash guard 106 overlies the take up roll assemnbly 86 on the interior of the cassette and is mounted in conventional fashion on the housing 94 in position to guard against splashing and contaminating dissemination of the separated and collected waste solids. A combination guideway and pressure plate 108 is mounted in alignment with the filter material 82 from the supply roll 84 and serves to guide the material into engagement with the take-up roll assembly 86. The guideway 108 is mounted so that it will act as a pressure plate in position to apply pressure to the collected filtered materials on the take-up roll assembly 86 as the roll expands in size thereby facilitating the retention of the waste and collected filter material on the roll. A take up tube 109 within the bottom of the cassette is interconnected with the disconnect 98 to provide an exit path for the filtered fluid.
A splash guard 110 is mounted on the interior of the housing 94 of the cassette adjacent to the upper opening 96 in the cassette and in position to extend downwardly and inwardly into contact with the filter material 82 coming off the supply roll 84. Splash guard 110 helps in preventing waste material entering through upper access opening 96 from contacting and contaminating the filter material contained on supply roll 84 and otherwise contaminating portions of the interior of the cassette 70 remote from the take-up roll 86 where the waste is to be collected.
An inlet filter pad 69 is incorporated in cassette assembly 70 to prevent solid particles from bypassing filter 82 and entering pump 68. Inlet filter pad 69 is held in position by filter pad supports 71.
The cassette 70 is removably replaceable through an opening in the housing assembly. A suitable removable plug can be taken out of the cassette to expose opening 96 before insertion and can be replaced after removal of the cassette to seal it for transportation and disposal. It is ready for use upon easy connection of the filter drive shaft 100 with the drive assembly on the housing and connection of the disconnect 98 with the conduit to the pump 68.
The processing manifold or module 56 is show in detail in FIGS. 6 and 7. The module includes motor 178 which is interconnected with the module 56 through motor speed reduce 112 and motor mounting plate 114 on the module. The module also includes a pad chamber 116, a switch assembly 118, a cam follower 120, a cam follower arm 122 and a cam 124. The cam follower arm is mounted at one end to a shaft 126 with the assistance of a set screw 128 and at the other end to the cam follower 120. Cam 124 is mounted to rotate about shaft 130 and is affixed thereto by means of set screw 132. The module 56 includes the flush valve assembly 58 and for that purpose a flapper 134 is normally engaged by tensioner 136 to overlie and seal opening 138 in the bottom of the manifold. A sealing gasket 140 is placed adjacent the peripheral edge of opening 138 for engagement with the flapper 134 to retain the discharge orifice in the manifold for the flush valve assembly normally in the closed position. An opening 142 is in the upper side of the manifold housing 144 for alignment with the discharge opening 146 in the toilet bowl assembly so that waste material can be flushed from the toilet bowl through discharge opening 146 in the bowl and through aligned openings 142 and 138 in the manifold when flapper 134 is shifted to the open position. When the flapper 134 is in the closed position, the bowl can be refilled with water for further use.
The valve assembly including flapper 134 is electrically operated upon an appropriate signal from the control board through the use of motor 178. An entrance opening 150 is in the module to provide introduction of a vent to the interior of cassette 70 for evacuation of displaced air after flushing system 20. Fluid is introduced to the interior of module 56 through solenoid valves 148. The fluid is subjected to treatment by an electrolytic cell 60 included in the module. The electrolytic cell includes a plurality of electrodes 152 and a plurality of stubs 154 for electrical connections to the electrodes. The electrodes are housed within a casing 156 with access being provided to the fluid circulating through the module for treatment of that fluid.
The flush valve assembly 58 formed as part of the module is electrically operated to operate in sequence along with the entrance, treatment and exit of recirculation fluid through the module. The module can be removed and replaced easily and efficiently when it is deemed to be desirable.
The toilet bowl assembly includes a conventional flush ring surrounding the upper rim portion of the bowl and the flush ring is conventionally connected for introduction of fluid to rinse the bowl. Fluid introduced through the flush ring into the bowl is normally retained in the bowl for dilution of the waste. This fluid adds in the transport of the waste material from the bowl through the flush valve assembly 58 into the cassette 70 at the same time rinsing and cleaning the bowl. Seat and cover assembly 89 is pivotable between the open and closed position in a conventional manner. The pumps in the system including pumps 68, and 32 are commercially available products and are designed to pump the fluid through the system. This includes transporting fluid from the exterior of the system to rinse and refill the toilet bowl after a flush, transporting filtered fluid from the cassette through a recirculation pathway, and transporting the fully treated fluid from the system as effluent fluid. All of the components through which fluid is directed in operation of the system are appropriately connected by suitable conduits or hoses mounted in a conventional manner to each interconnected element.
Operation of the system can be best understood when considered in light of the flow diagram of FIG. 8, the schematic electrical circuitry of FIGS. 9A and 9B and the timing diagram of FIG. 10. In general, the system is set up for use by placing a new cassette assembly 70 within the receiving recess in the lower housing 25 through the access opening therein. The cassette is positioned until the opening 96 in its upper end is in alignment with the discharge opening 146 in the toilet bowl assembly. A processing module 56 is also inserted through an access opening in the rear of the upper housing 24. The module 56 is inserted until upper opening 142 and lower opening 138 in the flush valve assembly 58 are in alignment with the discharge opening 146 of the toilet bowl assembly and the opening 96 into the cassette assembly. Suitable electrical connections and hose connections are made to the module 56 to integrate the module with the system in a quick and efficient manner. Similarly, the motor drive assembly including sprocket drive 74 and chain 76 is interconnected with the shaft 100 with its interconnected sprocket (not shown) extending from the side wall of the cassette so as to form a drive mechanism for take-up roll assembly 86. The appropriate hose is connected to fluid disconnect 98 to provide means for removal of fluid from the cassette. The system is then ready for use.
In general, the basic cycle starts with a downward action on the flush lever 28 which starts the rinse and refill pump 32 followed by the opening of the flush valve assembly 58. This allows the bowl contents to fall into the cassette 70 through opening 96. Rinse and refill pump 32 then stops and flush valve assembly 58 closes. The refill pump 32 turns on again long enough to rfill the bowl. The filter advancement motor 80 meanwhile is advancing the filter 82 in the cassette 70. Then the recirculation pump 68 turns on recirculating the fluid from the cassette 70 through the pump 68 and recirculation valve of valve assembly 62 and through the electrolytic cell 60 in the processing module 56 and back into the cassette 70 through an appropriate aperture in the module in alignment with an aperture back into the cassette. After a predetermined period of time, for example 4 minutes, the recirculation valve of valve assembly 62 closes the passageway to the processing module and opens the passageway to the exterior of the system thereby pumping the fluid out as effluent from the system. Pump 68 continues until the system is empty and ready for the next cycle.
In detail, the timing functions are accomplished with the assistance of three NE558 monolithic timing devices 160, 162, and 164. Each timing device contains four circuits which can be used to produce four entirely independent timing functions. A capacitor and resistor combination achieves the timing function. Each of the four circuits in connection with each timing device is identified by the subscript letters a through d respectively on FIGS. 9A and 9B. In the present system, this device is used primarily in a monostable (1 shot time delay) mode. The same device is also used as a set-reset flip-flop. This is achieved by leaving the timing capacitor out, therefore, essentially the monostable has a timing of 0 seconds.
When any of the timing devices 160, 162 and 164 is used in the one shot mode operation, it is necessary to supply a resistor and capacitor for timing. The time period is equal to the product of R (ohms) and C (farads). Since the output structure of the timing device is an open collector, it requires an output pull-up resistor. The output is normally low and is switched high when triggered. A trigger (start the timing) is achieved on the falling edge of the trigger pulse only, after previously being high. A reset is also available in each device to reset all sections simultaneously to an output low state. When the reset function is low, all outputs are set low and the trigger is inhibited.
Whenever the timing output of a NE558 timing device such as devices 160, 162 and 164 is needed to drive a relay, a high gain/high power D4OKI NPN transistor is used. Diodes are used across each relay coil to supress the transient voltage produced when de-energized. Diodes are also used across motors, pumps, and valves, to supress transient voltages.
Other components of the circuit include rinse pump relay 166, flush valve relay 168, cassette process relay 170, filter advance relay 172, electrolytic cell relay 174, flush valve index switch 118, flush valve motor 176, rinse pump 32, recirculating pump 68, recirculating valve 61, effluent valve 178, and filter advance motor 80. The flush lever 28 is attached to a spring return rotary switch 179. When the flush lever is turned downwards, it starts the rinse pump function through timing device 164B, the flush valve delay function through timing device 162D, the conditions to advance the filter through timing device 162A, the delay process function through timing device 160C, the main timer through timing device 160D, the effluent timer through timing device 160B, and the lever disable function through transistor 180.
In the rinse pump function, timing device 164B output goes high immediately upon turning the flush lever 28 downwards. Through diode 182, the output of device 164B saturates transistor 184 that pulls in rinse pump relay 166. The timing device 164B period is timed as determined by resistor 186 and capacitor 188 for 5.1 seconds. That is, the rinse pump 32 will push water from the sea through inlet tubes 34, 36 and 40 into the bowl for 5.1 seconds. This is the rinse interval of the rinse pump function. When timing device 164B completes its time period, its output goes low (to 0 volts). This is a command for timing device 164C to go high and stay high as determined by its resistor 190 and capacitor 192 and resistor 194 and capacitor 196 arrangements, for 4.3 seconds. This is the pause interval of the rinse pump function. The functional timing sequences can be easily seen in FIG. 10. When timing device 164C completed its time period, its output goes low. This is a command for timing device 164d to go high, and stay high for 5.1 seconds as determined by resistor 198 and capacitor 200. Through diode 202, the output of timing device 164D saturates transistor 184 again to pull-in rinse pump relay 166. Rinse pump 32 pushes water into the bowl this time to refill the bowl to its wet level determined by the timing device 164D period as set by resistor 198 and capacitor 200. This is the refill interval of the rinse pump function.
In the flush valve delay function, the flush lever 28 also starts the timing device 162D timing as set by resistor 204 and capacitor 206, its output going high and staying high for 2.2 seconds. At the end of the timing period of device 162D, timing device 160A goes high which saturates transistor 208 pulling in flush valve relay 168.
Flush valve relay 168, through the normally open contact of the flush valve index switch 118, puts voltage across the flush valve motor 176. Flush valve motor 176 drives the flush valve mechanism off its cam deactivating the flush valve index switch 118 which removes power from the flush valve motor 176, and allows the flush valve mechanism to snap the flush valve flapper 134 open.
This function together with the rinse interval of the rinse pump function achieves the following: the rinse pump 32 starts pushing water into the bowl, 2.2 seconds later the flush valve 58 snaps open unloading the bowl contents into the cassette 70 below, and rinses the bowl clean.
The conditions to advance the filter in the cassette include timing device 162A flip-flop being set by the lever switch. When the refill interval of the rinse pump function ends, device 162A resets through resistor 210. Device 162A reset is the command for device 162B to start its timing period of 15 seconds as determined by resistor 212 and capacitor 214. Through diode 216, transistor 218 saturates energizing filter advance relay 172.
With filter advance relay 172 energized, the filter advancement motor 80 will be powered as soon as rinse pump relay 166 ends its refill interval. The filter advance motor 80 advances the filter mechanism and cassette filter take-up assembly 86. This causes the filter roll 84 (provided it has some filter material 82 wrapped around it) to rotate. Filter roll 84 supports a small magnet 104 which also rotates. The reed switch assembly 78 contains three reed switches 120 degrees apart in a circle and senses that the magnet 104 has moved off one reed then onto another (it traveled 120 degrees) and, together with resistor 220, capacitor 222, and resistor 224 produce a reset pulse to reset timing device 162. Note that the reset pulse is produced only when all reeds are open, that is when the magnet 104 is not in the vicinity of a reed, and then any one is closed, that is when the magnet 104 is on top of a reed.
If the reed switch assembly 78 cannot produce a reset pulse for timing device 162, such as when the cassette is out of filter material 82, then timing device 162B will complete its 15 second timing period. The timing device 162B output then becomes a set command for flip-flop 162C. Device 162C saturates transistor 226, lights the red LED forming the change cassette light 90, and, through diode 221, prevents filter advance relay 172 from energizing. It should be noted that the reed switch assembly 78 cannot produce a reset pulse for resetting timing device 162 under the following conditions: (1) the cassette is out of filter material 82, (2) there is not enough filter material 82 for a 120 degree travel, (3) the cassette has filter material 82, however, the solids fill up the take-up roll cavity, thus stalling the filter advance motor 80, and (4) the filter becomes torn.
It should also be noted that the system 20 can be used for liquid flushes even though it is out of filter material. However, solid flushes should be avoided.
When a new cassette 70 is installed, the change cassette indicator 90 will extinguish by interrupting power with the control power circuit breaker. A reset pulse will be produced either by the reed switch assembly 78, if the magnet and reed line up, or by resistor 228 and capacitor 230 if the magnet and reed do not line up.
In regard to the delay process function, the device 160C output goes high with the flush lever 28. Transistor 232 saturates preventing transistor 234 from saturating. Therefore, the cassette process relay 170 cannot pull in for approximately 27 seconds. This timer allows the system 20 to rinse, refill, open and close the flush valve assembly 58, and advance the filter material 82 before it starts its recirculation cycle.
When device 160C times out, the 160D output through diode 236 and resistor 238, saturates transistor 234 pulling in cassette process relay 170. The recirculating pump 68 gets powered through the rinse pump relay 166, the filter advance relay 172, and the cassette process relay 170. In regard to the main timer function, device 160D output goes high with the flush lever 28. Although transistor 240 is saturated, electrolytic cell relay 174 cannot be pulled in until the delay process function of device 160C ends. Then, through the cassette process relay 170, diode 242, and saturated transistor 240, electrolytic cell relay 174 pulls in. Electrolytic cell relay 174, diode 244, cassette process relay 170 are the conditions needed to pull in recirculating valve 61. Also, electrolytic cell relay 174 completes the power circuit to the electrolytic cell.
The main timer 160D interval as determined by resistors 246 and 248 and capacitor 250 is 240 seconds.
In regard to the effluent timer, at the end of 240 seconds, timing device 160D goes low which de-energizes electrolytic cell relay 174. Electrolytic cell relay 174 and cassette process relay 170 energize effluent valve 178. Also, timing device 160B starts timing at the end of 160D. Device 160B through diode 256 and resistor 238 keeps transistor 234 saturated and cassette process relay 170 energized. This keeps recirculating pump 68 going for an additional 60 seconds as determined by resistor 252 and capacitor 254.
With the recirculating pump on, and the effluent valve energized, the treated liquids are discharged overboard.
In regard to the flush lever disable, diode 256 and diode 236 serve another function. They sum-up the main timer and effluent timer function, and, through resistor 257 saturate transistor 180. Transistor 180 lights the yellow LED which is the processsing light 88. Also, through diode 236 and diode 256 a voltage higher than 2.5 volts is produced across resistor 258 when either the main timer or the effluent timer is timing, which electrically disables the flush lever switch. That is not flushing can be achieved while the device is processing.
A 6 amperes circuit breaker 48 is provided with each system 20 to protect the rinse pump 32. Rinse pump 32 actually draws approximately 15 amperes but, because the rinse pump is activated for a few seconds, the over current is ignored by this circuit breaker.
If, however, due to a failure, the rinse pump stayed on for longer than a few seconds, circuit breaker 48 will remove power from rinse pump 32 thus preventing floods. Also, circuit breaker 48 could be used to switch power off the rinse pump for servicing, troubleshooting, and the like.
A 3 ampere circuit breaker 49 is also provided to protect all other active components. Individual protection is achieved by energizing one major component at a time. For example, power is held off the recirculating pump while the filter is advanced, etc. This circuit breaker is also used to remove control power from the system for servicing, cassette changing, and the like.
A 25 ampere circuit breaker is recommended for installation as near as possible to the battery. This protects against catastrophic failures.
The system is designed to operate at a maximum pitch and roll angle of 30 degrees. This is deemed advisable in marine environments. At these extreme angles, it is necessary to change the operation of flush valve assembly 58 such that the bowl is allowed to empty into the cassette. To achieve this, a photon coupled interrupter module is employed. This device houses an infrared emitting diode 258 coupled with a silicon photo transistor 260. The gap in the housing is interrupted by an opaque flag. This flag allows the light from the emitting diode to saturate the photo transistor when the system is pitched forward or rolled side ways for more than 15 degrees. This function is provided by unit 262, resistor 264, resistor 266, resistor 268, capacitor 270 and PNP transistor 272. It operates in the following manner. If the system's pitch or roll angle is more than 15 degrees, and the rinse pump relay 166 is energized, transistor 272 pulls flush valve relay 168 in, and the flush valve relay 168 stays in for approximately 10 seconds. This function is inoperative at all other times.
The time sequence of the system is clearly depicted in FIG. 10 and the flow sequence is clearly shown in the block diagram of FIG. 8. The waste is treated in the following manner, when the flush valve assembly 58 is opened, the solid and liquid waste in the bowl is dumped through the opening 146 in the bottom of the bowl with the assistance of rinse water supplied from an external water source introduced into the bowl. The combination of solid waste and fluid fall through the openings in the processing module 56 and into the opening 96 in the upper side of cassette 76. It is deposited on the filter material 82 in alignment with the opening in the cassette where the solid waste is substantially collected with the fluid passing through the filter material to the bottom of the cassette. The take up roll assembly 86 is advanced drawing the filter material 82 and collected solid waste thereon into engagement therewith. The triangular, or other polyagonal configuration, of the take up roll outer member 102 assists in capturing the waste material on the take up roll. The filtered fluid is pumped through inlet tube 109 out of the cassette through connector 98 and then through hose 66 to valve assembly 62 and through recirculation valve 61. From there the fluid is pumped through tube 64 back into the processing module for further treatment therein by the electrolytic cell 56. The fluid is then passed again from the module into the cassette for further filtering. This filtering cycle between the cassette and the processing module continues through a predetermined period of time and thereafter the effluent value opens to permit the treated fluid to exit the system through effluent tube 63. In this manner, the waste can be collected and the fluid discharged from the system in a clean condition which is acceptable to EPA standards.
Thus the several aforenoted objects and advantages are more effectively attained. Although several somewhat preferred embodiments have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereto and its scope is to be determined by that of the appended claims.
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A self-contained sewage waste disposal system including a housing structure and a toilet bowl adapted to receive human waste and fluid for diluting the waste, transporting the waste and rinsing the bowl. A removable filter cassette is in the housing in communication with the toilet bowl. Structure is provided for flushing the bowl and dumping the contents into the filter cassette and for subsequent refilling of the bowl. A filter is in the cassette for separating the particles of solid material from the fluid received from the bowl. The solid material is stored in the cassette in a compact manner for subsequent disposal upon removal of the cassette. Pumps and interconnected conduits are in the housing to transport fluid directly from an external source to fill the bowl after a flush, to transport and recirculate filtered fluid through the system for further waste disposal treatment, and to direct the effluent fluid from the system thereafter. Controls are provided to pass the fluid through the system and facilitate the collection and disposal of sewage waste within the system in a predetermined sequence.
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[0001] This is a divisional of U.S. patent application Ser. No. 10/641,179, filed on Aug. 14, 2003, which is a divisional of U.S. patent application Ser. No. 09/599,242 filed on Jun. 22, 2000, now abandoned.
BACKGROUND
[0002] This invention relates generally to electronic programming guides (also known as electronic content guides) for facilitating the selection of programming for viewing.
[0003] Conventionally, electronic programming guides provide a graphical display of programs that are available for viewing on a given channel at given times. Conventional electronic programming guides include a grid display with times across the horizontal axis and channels across the vertical axis. Each program associated with a given channel at a given time may be selected by mouse clicking on the program description. Upon selection, the program is automatically tuned for viewing.
[0004] While such content guides provide many advantages, there are many who would prefer to find programming content using topical or category style listings. Thus, some electronic content guides provide listings for particular categories of content such as movies or sports. However, these content guides generally dispense with any type of time and channel organization and simply list all of the content available within a given category.
[0005] Because the number of available programs at any instance in time is increasing rapidly, there is a continuing need for better ways to organize and implement electronic programming guides. Moreover, existing grid based displays require extensive scrolling to view the full extent of available program listings in some cable and satellite systems, it is sometimes difficult to quickly realize all of the available program options.
[0006] Thus, there is a need for an electronic content guide that better organizes the available content for easier selection and viewing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a view of a graphical user interface in accordance with one embodiment of the present invention;
[0008] FIG. 2 is a view of a graphical user interface of FIG. 1 after a particular program has been selected for more information;
[0009] FIG. 3 is another version of a graphical user interface for an electronic content guide in accordance with one embodiment of the present invention;
[0010] FIG. 4 is a variation of the graphical user interface shown in FIG. 3 in accordance with one embodiment of the present invention;
[0011] FIG. 5 is a flow chart for software in accordance with one embodiment of the present invention;
[0012] FIG. 6 is a flow chart for software in accordance with another embodiment of the present invention; and
[0013] FIG. 7 is a block diagram for hardware in accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
[0014] Referring to FIG. 1 , a graphical user interface 10 for implementing an electronic content guide includes a plurality of selectable category icons 12 represented as “virtual” file folders. Each category icon 12 may be predefined or may be user definable. Thus, in the embodiment illustrated in FIG. 1 , category icon 12 a is provided for favorite programs, 12 b for movies, 12 c for currently available programs, 12 d for programs available in the next hour, 12 e for sports programs, 12 f for news and 12 g for animal related content. Of course, the categorization of content is infinitely variable and a variety of different embodiments may be provided.
[0015] However, in some embodiments of the present invention, it is advantageous to organize the programming into both topical categories and time-based categories. Thus, the categories 12 a , 12 b , 12 e , 12 f and 12 g are topical categories in that they relate to some characteristic of the program other than time. In contrast, the icons 12 c and 12 d select time-based categories, namely programs available now and programs available in an hour. Additional time-based categories may be provided to cover time periods further into the future.
[0016] In the embodiment illustrated in FIG. 1 , the category icon 12 c has been selected as indicated by the highlighting 26 . A plurality of subcategory icons 14 are then displayed, for example as “virtual” file folders.
[0017] Conventionally, each of the subcategory icons 14 may be displayed in association with a particular one of the category icons 12 such as the current icon 12 c.
[0018] Thus, when the user selects currently available programs through the icon 12 c , the user may thereafter select currently available news programs through the icon 14 a , currently available sports through the icon 14 b , currently available movies through the icon 14 c , currently available drama series through the icon 14 d , currently available animal programs through the icon 14 e , currently available favorite programs through the icon 14 f and currently available series through the icon 14 g in one embodiment. Of course the variety of categorization within the icons 14 is highly variable.
[0019] One purpose of the category icons 14 may be to refine the amount of information that is displayed on a given graphical user interface. Another purpose may be to reduce the amount of information to an extent that the information is easily discernable in a single screen without excessive scrolling.
[0020] An icon 16 gives the current time. Thus, the current icon 12 c selects content currently available at the time indicated by the icon 16 .
[0021] In the illustration shown in FIG. 1 , the user has selected the current icon 12 c and the favorites subcategory icon 14 f both of which are highlighted. Thus, the user has selected favorite programs that are currently available in the illustrated example. The basis for defining favorites may be extremely varied. The user may simply enter what the user decides at any given instance of time, such as any given day of the week, are his or her favorite programs. As another example, the system can automatically discern what are the favorite programs based on how frequently the user views a given program over varying time periods.
[0022] In the illustration shown in FIG. 1 , a plurality of programs 22 are listed as entries in two columns 20 a and 20 b . These programs 22 are either currently in progress or just beginning, in keeping with the selection of currently available programs, through the icon 12 c , and favorites among currently available programs through the selection of the icon 14 f.
[0023] Thus, the X-Files program 22 , runs from 7:00 to 9:00 as indicated by the indicia 18 and 19 . The bar indicia 19 graphically indicates how much of the program has already been displayed or broadcast in the past using differently color indicia 18 and 19 . Since the X-Files started at 7:00 and the current time is 8:00, the bar indicia 19 indicates that the program is half completed. Through the juxtaposition of the start time, indicated as 7:00, and the end time, indicated as 9:00, and the bar indicia 19 , the user can determine the program timing and can determine how much of the program is left to view as indicated by the differently colored indicia 18 .
[0024] Similarly, other programs include a bar type indicia 19 of the available time left in a given program and conversely the amount of the program that has already been missed. In the case of programs that are just starting at the current time (8:00) such as ER, no such graphical bar is provided since no portion of the program has been missed. To select a given program for viewing, the user simply clicks on the program listing 22 and the program is automatically displayed for viewing.
[0025] A plurality of additional icons may be provided such as a search icon 34 , a record icon 36 and a chat icon 38 . The search icon 34 brings up a graphical user interface that facilitates a keyword search through all the programs available through the graphical user interface 10 . The keyword search may search through descriptive textual material stored in association with one or more programs.
[0026] The record icon 36 facilitates the recording of any program on the graphical user interface 10 . In one embodiment of the present invention, the user can simply click on a given program and drag and drop it into to the record icon 36 , to automatically cause a given program to automatically be recorded. The chat icon 38 may be selected after selecting a given program to automatically enter a chat room associated with a given program.
[0027] Turning next to FIG. 2 , the user has mouse selected a program 22 as indicated by the positioning of the mouse cursor 32 over the entry 22 . In response to selection of the entry 22 , an expanded graphical user interface 21 is produced which overlays the column 20 b ( FIG. 1 ). The interface 21 provides additional information about the selected program entry 22 . In this case, additional material 40 is given about the program in general. For example, the title of the program, the stars, and a description of the particular episode may be provided in the material 40 . In addition, information may be provided about the current stage of the program. This information may include a video thumbnail 44 depiction of the current frame being displayed plus a description 42 of the particular stage of the program. For example, the description 42 may be provided for a particular chapter or other subdivision within the program 22 . However, the description 42 may be even more timely, indicating what is currently going on at that instance in the given ongoing program.
[0028] In addition, the type of content associated with the program, such as science fiction, is indicated at 48 . A star system 41 may also be provided to indicate the degree to which the program is one of the user's favorites. For example, based on the number of times that the user watches the series, a program in the series may be given a star rating 41 from one to four stars in one embodiment. This information may be helpful to the user in determining that in fact this program is the one that the user wishes to watch.
[0029] In some embodiments, the entries 22 may be ordered from top to bottom in each column 20 based on the frequency with which the user views the series that includes program represented by an entry 22 . For example, the programs with the highest star rating 41 may be listed prominently at the top of the columns 20 .
[0030] Turning next to FIG. 3 , a graphical user interface 10 a displays entries 22 that satisfy the currently available category icon 12 c and favorites subcategory 12 f , where the number of these entries 22 exceeds the capacity of the two column display shown in FIG. 1 . In this case, a three column display is automatically constructed including columns 20 a , 20 b and 20 c.
[0031] While the size of the text associated with each column 20 in FIG. 3 may be unchanged from that shown in FIG. 1 , the amount of information, shown in each column 20 may be decreased in one embodiment. For example, the time information may be cut off in the graphical user interface 10 a shown in FIG. 3 to provide enough room to display, on a single display screen, all of the appropriate programs. In some embodiments, additional scrolling may be necessary to see all the available programs.
[0032] If the user wants additional information about a program, the user may select a particular program as indicated by the cursor 32 (on the program Animal Adventures) to cause additional information such as the time information to scroll into view as indicated at 24 in FIG. 4 . Thus, additional information may be made available by scrolling the display for each entry 22 .
[0033] The user can also click on the displayed entry 22 to receive the additional information, as shown in FIG. 2 , through the interface 21 . Thus, if the user right clicks on an entry 22 , the user may get the interface 21 and if the user left mouse clicks the user gets the scrolling shown in FIG. 4 , as one example. To actually select an entry 22 for viewing, the user may double click on the entry 22 , in one embodiment.
[0034] The software 50 for implementing the graphical user interface 10 , in accordance with one embodiment of the present invention shown in FIG. 5 , begins by determining whether a category icon 12 has been selected as indicated in diamond 52 . If so, the associated subcategory icons 14 are displayed as indicated in block 54 . Thus, in some cases, particular subcategory icons 14 may be associated with a given category icon 12 . A check at diamond 56 determines whether one of the subcategory icons 14 has been selected. If so, associated programs 22 are displayed as indicated in block 58 . A check at diamond 60 determines whether the user has double clicked on an entry 22 . If so, the software 50 automatically tunes the program for viewing as indicated in block 62 .
[0035] Otherwise, a check at diamond 64 determines whether a single click has occurred. If so, additional information may be displayed through the interface 21 shown in FIG. 2 , for example, as indicated in block 66 .
[0036] A check at diamond 68 determines whether the user has dragged and dropped a program into the record icon 36 . If so, the program is automatically scheduled for recording as indicated in block 70 .
[0037] The set-up software 80 , shown in FIG. 6 , for setting up the electronic content guide 10 shown in FIG. 1 begins by receiving user category input listings to complete the category icons 12 as indicated in block 82 . Next, the software 80 receives input data in the form of user subcategory icon entries 14 as indicated in the block 84 . Thereafter, the software 80 may receive the actual entries for a given subcategory in the form of program entries 22 in one embodiment of the present invention, illustrated by the block 86 .
[0038] The information received in blocks 82 , 84 and 86 may then be assembled into a graphical user interface (block 88 ). For example, depending on the number of programs that fit within a given category and subcategory, a two column graphical user interface 10 may be assembled as indicated in FIG. 1 or a three or more column interface 10 a may be assembled as indicated in FIG. 4 . In addition, the icons 12 and 14 are generated in the file folder format shown in FIG. 4 in accordance with one embodiment of the present invention.
[0039] The number of columns 20 is determined based on the number of programs that satisfy a given category and subcategory as indicated in block 90 . If the number of columns is greater than a predetermined number as determined in diamond 92 , the scroll feature may be provided. In such case, the amount of information displayed may be reduced from that shown in FIG. 1 , for example, to the format shown in FIG. 3 where scrolling is utilized to obtain the time information. In other embodiments of the present invention, depending on the number of program entries to be displayed the size of the individual entries 22 may be reduced by making the font smaller or changing the number of entries per column.
[0040] Turning finally to FIG. 7 , a processor-based system 100 for implementing one embodiment of the present invention includes a processor 102 coupled to a north bridge 104 . The system 100 , for example, may be a desktop computer, a laptop computer, a handheld computer, a processor-based appliance or a set-top box as illustrated in FIG. 7 .
[0041] The north bridge 104 couples a system memory 106 and a decoder 110 (via the link 114 ). The decoder is coupled to a demodulator/tuner 108 and may be coupled to a source of television programming such as a cable connection, the Internet or a satellite receiver. The decoder 110 is also coupled to a television receiver 112 . The decoder 110 separates audio and video demodulated content and provides the video information to the north bridge 104 and the audio information to the south bridge 116 by the bus 124 in one embodiment.
[0042] The south bridge 116 communicates with the coder/decoder (codec) 120 that provides an audio output through amplifiers and speakers 122 . A hard disk drive 118 is coupled to the south bridge 116 to store software programs 50 and 80 . A firmware hub 132 may store basic information for operation of the system 100 . The firmware hub 132 may be flash memory or other non-volatile memory in one embodiment of the present invention. The hub 132 may also store information about particular television programs which is desirable to maintain in a non-volatile memory.
[0043] A serial input/output (SIO) device 126 is coupled to an interface 128 which, in one embodiment of the present invention, is a wireless interface such as a radio or infrared interface. The interface 128 communicates with a remote control unit 130 that operates through a compatible interface.
[0044] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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An electronic content guide may organize content such as television programs into categories and subcategories. The categories and subcategories may be topical as well as time-based. As a result, the user can select a given time-based criteria and within that time-based criteria select topical subcategories. As a result, the number of programs that may be displayed in any given graphical user interface may be reduced to a manageable level. This may be done without requiring a great deal of scrolling to view selected categories, subcategories and particular programs.
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This nonprovisional application claims the benefit of U.S. Provisional Application No. 60/110,470 filed Nov. 30, 1998.
This work was supported in part by Grant No. GM 13326-26 from National Institutes of Health.
BACKGROUND OF THE INVENTION
The following references are incorporated herein in their entirety by reference: Certa, H., Fedtke, N., Wiegand. H. J., Miller, A. M. F., Bolt, H. M. Arch. Toxicol. 1996, 71, 112-122; EPA method 604, Phenols in Federal Register, Oct. 26, 1984. Environment Protection Agency, Part VIII, 40 CFR Part 136, 58-66; EPA method 625, Base/neutrals and acids in Federal Register, Oct. 26, 1984. Environment Protection Agency, Part VIII, 40 CFR Part 136, 154-174; Puig, D., Barceló . Trends in Anal. Chem, 1996, 15(8), 362-375; Li, N., Lee, H. K. Anal. Chem. 1997, 69, 5193-5199; Bender, M. L., Komiyama, M. Cyclodextrin Chemistry , Springer-Veriag, Berlin, 1978; Breslow, R., Bovy, P., Hersh, C. L. J. Am. Chem. Soc. 1980, 102, 2115; Szejtli, J. Cyclodextrin Technology , Kluwer Academie Publishers, Boston, 1988; Editor Sant'e, D. Minutes of the Sixth International Symposium on Cyclodextrins , Paris, 1992; Editor Bethell, D. Advances in Physical Organic Chemistry, 1994, Volume 29, 1-85, Academic Press. New York; Chen, E. T., Pardue, H. L. Anal. Chem. 1993, 65, 2583-2587; Ikeda, H., Kojin, R., Yoon, C.-L., Ikeda, T., Toda, F., J. Inclusion Phenom. 1989, 7, 117-124; Chen, E. T. unpublished cytotoxicity report of the mM-β-DMCD; Alarie, J. P., Vo-Dinh,T. Talanta, 1991, 38(5), 529-534; Zhao, S., Luong, H. Y. Analytica. Chimica Acta, 1993, 282, 319-327; Liu, H., Li, H., Ying, T., Sun, K., Qin, Y., Qi, D. Analytica. Chimica Acta, 1998, 358, 137-144; Li, G., Mcgown L. B. Dissertation Abstracts International. 1994, 56/02-B; Li, G., Mcgown, L. B. Science, 1994, 264, 249-251; Mallouk, T. E., Harrison, D. J. (editors) Interfacial Design and Chemical Sensing, 1994, ACS Symposium Series 561; Roberts, S. M. Molecular Recognition, Chemical and Biochemical Problems , Royal Society of Chemistry, 1989; Chidsey, C. E. D. Science, 1991, 251, 919-922; Nuzzo, R. G., Fusco, F. A., Allara, D. L. J. Am. Chem. Soc. 1987, 109, 2358-2368; Spasov, A. Ann. Univ. Sufia, II Faculte Phys. Math. Livre, 1939, 2(35), 289-291; Chen, E. T. Dissertation of Ph.D. Title “A Study of Analytical Application of the Catalytic Properties of Cyclodextrons” 1994; Chung, C. Dissertation of Ph.D. Title “Spontaneously Adsorbed Monolayer Films: Fabrication, Characterization, and Application of Monolayers of Alkanethiol and Sulfur-bearing”, 1990; Markowitz, M. A., Bielski, R., Regen, S. L. J. Am. Chem, Soc., 1988, 110, 7545-7546; Gregg, B. A., Heller, A. J. Phys. Chem. 1991, 95, 5976-5980; Komiyama, M. Ange. Macromole. Chemie, 1988, 163, 205-207; Koradecki, D., Kutner, W. J. Incl. Phenom. 1991, 10, 79-96; Lehn, J. M. Science, 1985, 227, 849; Proceedings of the NATO Advanced Research Workshop on Chemosensors of Ion and Molecular Recognition , Kluwer Academic Publishers, Bonas, France, 1997; (Editors) Scheller, F. W., Schubert, F., Fedrowitz, J. Frontiers in Biosensorics , (books one and two), Birkh-user Verlag Base, Boston, 1997; Szejtli, J., Szente, L. Proceedings of the Eighth International Symposium on Cyclodextrins , Budapest, Hungary, Kluwer Academic Publishers, Boston, 1996; Dagani, R. C & EN. Jun. 8, 1998, 35-46; Pardue, H. L. Anal. Chim. Acta, 1989, 216, 69-107; Williams, M., Pardue, H. L, Uhefbu, C. E., Smith, A. M., Studley, J. Talanta, 1996, 43, 1379-1385; Lim, K. B., Pardue, H. L. Anal. Chim. Acta, 1996, 329, 285-295; Wang, X., Pardue, H. L. Anal. Chem. 1997, 69, 4482-4489; Kotte, H., Grundig, B., Vortop, K-D., Strehlitz, B., Stottmeister,U. Anal. Chem. 1995, 67, 65-70; Bucke, C. Polysaccharide biotechnology-a Cinderella subject, Trends in Biotech. 1998, 16(2), 50-52; Ross, et al. Arch. Pathol. Lab. Med. 1998, 122:587-608; Wang, J. Anal. Chim. Acta 1997, 337:41; and Biosensors and Electronic Noses , Kres-Roger, Editor, CRC Press, N.Y., 1997.
FIELD OF THE INVENTION
The present invention relates to the field of biosensors and, in particular, to biosensors comprising a catalytically active cyclodextrins.
DESCRIPTION OF RELATED TECHNOLOGY
Many chemicals in common use in industrialized societies contain aromatic esters. Examples of the types of chemicals containing aromatic esters include detergents, antioxidants and agricultural chemicals. Upon degradation of these aromatic esters whether through enzymatic hydrolysis or bacterial degradation, toxic phenols and phenol derivatives are produced. Research has shown that these toxic chemicals can accumulate in food, soil, and water. In addition, it has been shown that the presence of these chemicals can be dangerous to humans and animals as they can have adverse effects on reproduction and have been implicated in the development of tumors (Certa et al. 1996). The United States Environmental Protection Agency (US-EPA) has listed phenolic compounds as priority pollutants due to their toxicity and persistence in the environment (EPA method 604, Phenols in Federal Register, Oct. 26, 1984, Environment Protection Agency, Part VIII, 40 CFR Part 136, 58-66; EPA method 625, Base/neutrals and acids in Federal Register, Oct. 26, 1984. Environment Protection Agency, Part VIII, 40 CFR Part 136, 154-174). Furthermore, European Community Directive 76/464/EEC recommends that the maximum level of phenolic compounds in surface water for drinking purposes should be in the 1-10 μg/L range (Puig et al.). Therefore, developing a sensitive, reliable, and fast testing method for the detection of phenolic compounds is an issue of importance to the entire industrialized world.
Current methods for the detection of phenolic compounds include liquid chromatography with electrochemical (LCEC) detection and a coupled gas chromatography/mass spectrometry (GC/MS) method which requires sample pretreatment (Puig et al. 1996; Li et al. 1997). These currently employed methods suffer from various limitations. For example, the LCEC method is subject to interference because of the high applied potential (around 1V) required for electrochemical detection of the phenolic compounds. The high polarizing potential causes oxidation of other matrix compounds; hence, an increase in background current is frequently observed. In addition, the LCEC method has problems with signal stability, pH dependence, and time consuming experimental protocols. The GC/MS method usually requires sample derivatization prior to analysis. For example, Li and co-workers (Li et al. 1997) converted phenols to phenyl acetate prior to analyzing with GC/MS. It has been suggested by Puig (Puig et al. 1996) that the US-EPA method for derivatization of nitrophenols for GC/MS may often lead to incorrect results.
Conventional electrochemical methods used to detect toxic phenols suffer from signal drift, and the probes need frequent cleaning because of polymerization caused by oxidation of phenols (Puig et al. 1996). Because traditional electrochemical methods are sensitive to pH they have limited practical application. To date, no satisfactory approach exists for measuring phenols. Cyclodextrins (CDs) and modified CDs have been used as biomimetic enzyme (BMZ) catalysts for several decades (Bender et al. 1978; Breslow et al. 1980; Szejtli et al. 1988; Editor Sant'e, D. Minutes of the Sixth International Symposium on Cyclodextrins , Paris, 1992; Editor Bethell, D. Advances in Physical Organic Chemistry, 1994, Volume 29, 1-85, Academic Press, N.Y.). CDs are cyclic carbohydrates made up of six (α-CD), seven (β-CD) or eight (γ-CD) linked D-glucopyranose units. They look like hollow truncated cones, where the interior cavity is hydrophobic and the outside is hydrophilic. The cavities can entrap a variety of chemicals having suitable size and hydrophobicity. Functional groups can be attached to the CDs enabling them to mimic enzyme catalysis. For example, one or two imidazolyl groups attached on the C-3 position of the dimethyl-β-cyclodextrin (β-DMCD) can enhance catalysis of the hydrolysis of paranitrophenyl acetate (p-NPA) to para-nitrophenolate (p-NPO − ) with rate increases up to several thousand times the un-catalyzed rate (Chen et al. 1993; Ikeda et al. 1989). The nomenclature used to identify the imidazole modified β-DMCDs is mM-β-DMCD for mono-imidazolyl substituted β-DMCD and bM-β-DMCD for bis-imidazolyl substituted β-DMCD. The M before β in the abbreviation represents imidazolyl group. mM-β-DMCD has been used in solution to mimic the natural enzyme β-chymotrypsin. The protease β-chymotrypsin has a pH optimum of 8.2 for the hydrolysis reaction of p-NPA and achieves only a modest rate acceleration at this pH. In contrast, mM-β-DMCD can work at wide range of pH values. In addition, these modified CDs have good stability, and have unique solubility in both aqueous and organic phases. The mM-β-DMCD showed good selectivity for p-NPA and the cytotoxicity of mM-β-DMCD has been studied (Chen et al. 1993; Ikeda et al. 1989; Chen, E. T. unpublished cytotoxicity report of the mM- -DMCD).
Biosensors of the prior art generally contain immobilized enzymes on the surface of an electrode. This type of biosensor has found application for the detection of various analytes. Systems of this type generally include a mediator that functions to shuttle electrons from the electrode to the electrochemically active species detected. The biosensors of the prior art based on immobilized enzymes have a major flaws in that the response time is dependent upon the concentration of the analyte and the requirement for a mediator introduces an additional complexity and source of error.
New types of biosensors have been developed utilizing CDs and CD derivatives. The unique properties of CDs have been used to enhance the performance of biosensors with both optical and electrochemical detection. Examples of the use of CDs in sensors are provided by U.S. Pat. No. 5,540,828 to Yacynych, U.S. Pat. Nos. 5,587,466 and 5,480,924 issued to Vieil, et al. and U.S. Pat. No. 5,432,274 issued to Luong, et al., the specifications of which are specifically incorporated herein by reference. A variety of analytes can be detected in a fast, selective and sensitive way using CDs. Alarie and co-workers have developed a fiber-optic CD-based fluorescence sensor that utilized CDs' inclusion property to detect pyrene (Alarie et al. 1991). When using traditional electrochemical methods, electron mediators are needed in most cases; however, most of the mediators are toxins. Luong and co-workers used modified CDs to form a water soluble complex with tetrathiafulvalene (TTF) and used the complex as an electron mediator for a glucose biosensor (Zhao et al. 1993). The inclusion property of CDs was used in the development of an amperometric glucose biosensor as reported by Liu and coworkers (Liu et al. 1998). Recently, CDs, together with inclusion compounds, were found to form molecular nanotubes through self-assembly (Li et al., Dissertation Abstracts International 1998; Li et al., Science 1994). Molecular self-assembly technology for developing membranes is recognized as superior to conventional techniques because it can provide varying degrees of spatial and orientation arrangements of amphiphilic molecules on variety of surfaces of substrates as reported elsewhere (Mallouk et al. 1994; Roberts 1989; Chidsey 1991; Nuzzo et al. 1987). The formation of nanotubes made with CD and diphenylhexatriene based on the molecular inclusion has reported in the literature (Le et al. 1994).
One analytical technique which may be used in conjunction with a biosensor is cyclic voltammetry. In cyclic voltammetry, the potential of the electrode is scanned linearly from an initial value to a second value and then back to the initial value or some other potential. As the potential is scanned in the positive direction, an anodic current occurs when the electrode becomes a sufficiently strong oxidant to oxidize the analyte. The anodic current increases rapidly until the concentration of the analyte on the electrode surface approaches zero corresponding to a peak in the current. The current then decays as the solution surrounding the electrode is depleted of the analyte due to the conversion of the analyte into an oxidized form. When the highest potential of the scan is reached, the potential is scanned in the negative direction. When the electrode becomes a sufficiently strong reductant, the oxidized form of the analyte is reduced back to the original form. This reduction causes a cathodic current that increases until the concentration of the oxidized form of the analyte on the electrode approaches zero at which point the current peaks. The cathodic current then decays as the solution of the in the vicinity of the electrode is depleted of the oxidized form of the analyte. The cycle is completed when the potential returns to the initial value or to another predetermined potential value. Additional scans may then be made. When the oxidized form of the analyte is not reduced during the scan back to the starting potential, the reaction is said to be irreversible. The parameters determined in a cyclic voltammogram are the magnitude of the anodic peak current, i pa , the anodic peak potential, E pa , the cathodic peak current, i pc , and the cathodic peak potential, E pc . The pseudo first order rate constants can be obtained from plots of the ln(i ∞ -i t ) where i ∞ is the maximum current and i t is the current at time t.
Notwithstanding the above mentioned uses of CDs, utilizing the catalytic and molecular recognition features of mM-β-DMCD for biosensor development is difficult for the following reasons: (1) low coverage due to the monolayer defects, (2) low sensitivity and (3) low reproducibility as reported in the literature (Chung 1990; Gregg et al. 1991; Komiyama 1988; Koradecki et al. 1991). Thus, there exists a need in the art for a biosensor specific for phenolic compounds. In addition, there exists a need in the art for biosensors that do not utilize electron mediator molecules. These and other needs have been met by the present invention.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a novel biosensor. In preferred embodiments, the biosensor of the present invention may comprise an electrode and a catalytically active cyclodextrin affixed thereto.
It is an object of the present invention to provide a biosensor specific for the detection of phenolic compounds. In preferred embodiments, the biosensor of the present invention may comprise a β-DMCD comprising one or more imidazole groups. In a most preferred embodiment, the biosensor of the present invention may comprise a mM-β-DMCD.
It is an object of the present invention to provide a biosensor capable of detecting molecules of interest that does not require the inclusion of a mediator.
It is an object of the present invention to provide a method for detecting an analyte of interest comprising the steps of contacting a solution containing the analyte with a biosensor and detecting the analyte wherein the biosensor comprises a catalytically active cyclodextrin.
It is an object of the present invention to provide a method of detecting the presence of o-NPA in solution comprising the step of contacting a solution containing o-NPA with a biosensor, which biosensor comprises a catalytically active cyclodextrin. In preferred embodiments, the cyclodextrin may be mM-β-DMCD.
SUMMARY OF THE INVENTION
The present invention provides a novel biosensor comprising an electrode with a catalytically active cyclodextrin attached thereto. In a preferred embodiment, the novel biosensor of the present invention comprises a modified cyclodextrin capable of catalyzing the hydrolysis of NPA thereby making possible the measurement of nitrophenyl acetate (NPA) without the use of an electron mediator. In other preferred embodiments, the catalytically active cyclodextrins of the present invention may be assembled in the form of nanotubes.
The electrode of the present invention may be constructed of any material customarily used by those skilled in the art for the construction of electrodes. In preferred embodiments, the electrode may be glassy carbon, gold or silver. In a most preferred embodiment, the electrode may be glassy carbon.
The biosensor of the present invention may be constructed by coating the surface of an electrode with a catalytically active cyclodextrin to form a membrane. This coating may be accomplished by any means known by those skilled in the art. In addition to a cyclodextrin, the electrode may be coated with one or more compounds. In preferred embodiments, the electrode may be coated with a catalytically active cyclodextrin and a polyethylene glycol (PEG). In another preferred embodiment, the electrode may be coated with a catalytically active cyclodextrin, a PEG and a polyvinylpyridine (PVP). In a most preferred embodiment, the cyclodextrin will be deposited in the form of nanotubes and will be applied by co-polymerization of mM-β-DMCD with polyethylene glycol diglycidyl ether (PEG) and poly(4-vinylpyridine) (PVP).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1. A representation of the structure of a catalytically active cyclodextrin.
FIG. 2. A representation of the structure of PVP.
FIG. 3. A representation of the structure of PEG.
FIG. 4. A micrograph obtained by Scanning Tunneling Microscopy (STM) of the surface of gold substrate coated with mM-β-DMCD in the presence of PVP and PEG.
FIG. 5. A micrograph obtained by Scanning Electron Microscopy (SEM) of the surface of gold substrate coated with mM-β-DMCD in the presence of PEG.
FIG. 6. A micrograph obtained by Scanning Electron Microscopy (SEM) of the surface of gold substrate coated with mM-β-DMCD in the presence of PVP and PEG.
FIG. 7 . Cyclic voltammogram obtained with the sensor of the present invention.
Panel A shows the results obtained with o-NPA, Panel B shows the results obtained with p-NPA and Panel C shows the results obtained with m-NPA, Panel D shows the results of o-NPA with an un-coated glassy carbon electrode.
FIG. 8 . Cyclic voltammogram of o-NPA obtained with a two component sensor.
FIG. 9 . Cyclic voltammogram of o-NPO − obtained with a three component sensor.
FIG. 10 . Amperometric response curve showing bare electrode response to o-NPO − and response of three component sensor to o-NPA and o-NPO − .
FIG. 11 . Amperometric response curve showing response of bare electrode to o-NPA and o-NPO − and three component sensor response to o-NPA.
FIG. 12 . Amperometric response cure showing response of three component sensor to varying concentrations of o-NPA.
FIG. 13 . Calibration curve plotting the data of FIG. 12 .
FIG. 14 . Graph showing the operational stability of the present invention as a function of time.
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLE 1
Construction of the Biosensor
The mM-β-DMCD as a biomimetic enzyme was synthesized as described earlier (Chen et al. 1993; Ikeda et al. 1989; Chen, E. T. unpublished cytotoxicity report of the mM-β-DMCD). Briefly, β-DMCD may be reacted first with sodium hydride in dry tetrahydrofuran under a nitrogen atmosphere at 35-38° C. for 10 hours. The solution is then cooled to 0° C. and mixed with a solution of 2-(4-imidazolyl)-ethyl bromide in tetrahydrofuran and heated to 25° C. for 10 hours to produce the mono-imidazolyl CD and 20 hours to produce the bis-imidazolyl CD. The reagents used were prepared as follows. Polyethylene glycol diglycidyl ether (PEG, MW 400, Polyscience Inc, PA 18976) was used as received. The poly(4-vinylpyridine) (PVP) (MW 50,000, Polyscience Inc, PA 18976) was purified before use by dissolving PVP into methanol and adding ether for precipitation. The precipitate was rinsed and dried. Acetonitrile was freshly distilled. o-NPA and p-NPA (Aldrich) were re-crystallized from hexane. m-NPA was synthesized according to a published method (Spasov 1939) and the purity was tested by using gas chromatography. All analyte solutions were prepared in acetonitrile and stored at 4.0° C. for 24 h before use. The aqueous buffer solutions at 0.067 mol/L concentration were prepared with various pH values for the pH dependence study. The electrolyte, potassium chloride, was used in the buffer solutions at 0.1 M KCl concentration. All solutions were prepared in deionized water that had been previously distilled (Corning megapure distillation apparatus, Corning Inc., Corning, N.Y.) and filtered through 0.2 μm pore size membrane filter (Nylon-66, Rainin Instrument Co., Inc., Woburn, Mass.). Sodium 4-(2-hydroxyethyl)-1-piperazineethanesulfonate (HEPES, Aldrich) was used as received. A solution of mM-β-DMCD (2g/L) was prepared in THF, and the PEG was prepared in water (2.3 g/L). A 0.4 mg/mL PVP solution was prepared in a 50:50 (v/v) mixture of methanol and HEPES at pH 8.2. The various ingredients may be prepared as a solution in any suitable solvent in which they are soluble. The concentrations of the solutions may be varied without affecting the practice of the present invention. The cyclodextrin solution may be from about 2 to about 4 mg/mL; the PVP solution may be from about 0.4 to about 4 mg/mL and the PEG solution may be from about 2 to about 3 mg/mL. These three solutions of PVP, PEG, and mM-β-DMCD may be mixed in various proportions to generate the three component sensor coating of the present invention. In preferred embodiments the mixture may contain from about 3 to about 8 parts PVP solution, from about 2 to about 4 parts PEG solution and from about 8 parts to about 12 parts cyclodextrin solution. In a most preferred embodiment, the solutions may be mixed in the ratio of 5:2:10 (v/v) and this ratio was tested in sensor 1. A two component sensor coating may be constructed by omitting the PVP solution. In preferred embodiments the mixture may contain from about 2 to about 3 parts PEG solution and from about 7 parts to about 8 parts cyclodextrin solution. In a most preferred embodiment, the two component sensor may be made using a 30/70 ratio of PEG/mM-β-DMCD and this ratio was used for sensor 2. Capped containers with two- or three-component solutions were deoxygenated.
Preparation of the Biosensor
In a preferred embodiment, the reactor/sensor device may comprise mM-β-DMCD cross-linked with PEG and PVP (for sensor 1), or mM-β-DMCD cross-linked with PEG (for sensor 2) coated onto the surface of a glassy-carbon (GC) electrode (3 mm diameter, Bioanalytical System, West Lafayette, Ind. 47906). In other embodiments, the electrode may be made of any material known to those skilled in the art for the construction of electrodes. In other preferred embodiments, the electrode may be constructed of gold, silver, platinum or other metals.
Those skilled in the art will appreciate that the following description of construction of the biosensor of the present invention employs a glassy carbon electrode and can be readily adapted to construction of sensors using other electrode materials. Prior to coating, the GC electrode was polished using alumina and then rinsed and placed in a sonicating water bath for several minutes. Then the electrode was rinsed thoroughly with twice distilled water before use. A 2 μL aliquot of mixed solution was coated onto the surface of the electrode. After coating, the sensor was put in an oven for 48 h at 37.0° C. After drying, the coated electrode was rinsed with twice distilled water for 10 minutes and dried in an oven for 2 h. The surface morphology of the BMZ sensor was imaged by STM (Nanoscope II, Digital Instrument), and SEM (JSM-35C, JEOL LTD, Japan). A microwave vacuum plasma cleaner was used to clean the substrate surface (Opthos Instrument, Md.). For the STM experiments, a 1×1 cm 2 gold (111) crystal film was cleaned by a microwave vacuum plasma cleaner, was dipped into prepared solutions for a day, was dried in the oven for 2 h, and was then ready for the STM image. For the SEM experiment, a gold (111) film of 2×1.5 cm 2 was immersed into a two-component mixture solution, then the procedures were followed as above.
Instrumentation
The BMZ sensors were characterized using a cyclic voltammetry (CV-27, Bioanalytical System Inc., West Lafayette, Ind. 47906). Time-dependent responses for the amperometric method were recorded with the same equipment under the amperometric mode with a controlled constant polarizing potential. The output signal was digitized (Lab Master, Scientific Products, Cleveland, Ohio 44139) and stored on-line with a computer (Gateway 2000 ) with a math coprocessor. The glassy carbon (GC) electrode was the working electrode. The reference electrode was silver/silver-chloride and the auxiliary electrode was Pt.
Amperometric Measurements
All measurements were made on 20.0 mL solutions kept at 25.0° C. (except the temperature effect study) in a water-jacketed, single-compartment electrochemical cell. Test solutions were covered all times by a stream of nitrogen that had passed through a saturated solution of sodium sulfite to remove oxygen. A polarizing potential of −0.80 V was applied, and when the Faradic current decayed to a steady-state (s-s) value, the analyte (1.0 mL) was injected. Signal acquisition (1 point/s) began when the background current reached steady-state. The stirring rate was held constant using a NUOVA II stirrer (Barnstead Thermolyne Inc., Dubuque, Iowa).
Cyclic Voltammetric (CV) Measurements
For the CV measurement, the potential sweep range may be set from −0.8 V to 0.8 V. The scan rate was set at 20 mV/s for all experiments. The concentration of NPA isomers were 0.20 mmol/L in carbonate buffer at 9.87, 25.0° C. for the molecular recognition study. Those skilled in the art will appreciate that the experimental parameters may be adjusted to optimize the results obtained for various analytes and biosensors. For example, when the electrode is constructed of silver, the scan range may be adjusted to −0.8 to 0 V to avoid oxidation of the silver electrode at higher positive potentials.
EXAMPLE 2
BMZ Nanotube Device
FIGS. 1-3 show the structures of mM-β-DMCD, PVP and PEG used for fabrication of the biomimetic sensors. Sensor 1 is constructed using all three components and sensor 2 is constructed with only two components as PVP is omitted. The nanotube structures from self-assembly of mM-β-DMCD-PVP-PEG (sensor 1) on the surface of a gold (111) crystal planar electrode as imaged by STM are shown in FIG. 4 . The structure of the molecular nanotube of mM-β-DMCD linked by PVP and PEG was imaged by a Scanning Tunneling Microscope (STM) on a gold (111) crystal film at setpoint 11.0 nA with 199.9 mV bias. The average length and width of the three nanotubes visible in FIG. 4 are 26.2±1.0 nm and 2.5 nm, respectively. The packing density of the nanotubes on the crystal gold (111) planar electrode, as revealed by STM images, influences sensor performance as discussed later.
FIG. 5 is a Scanning Electronic Microscopy (SEM) image of the surface of mM-β-DMCD linked by PEG on a crystal gold (111) substrate (2×1.5 cm 2 ) by a spontaneously adsorbed method.
In FIG. 5, the SEM image of sensor 2 shows the two component coating forms a polycrystalline film on the surface of a gold (111) planar electrode.
FIG. 6 is an SEM image of the surface of mM-β-DMCD linked by PEG and PVP on a crystal gold (111) substrate. FIG. 6 shows that the three component system forms nanotube structures. Tubules with varying length were observed on the crystal gold (111) planar surface. Comparing the two physical structures produced by the two different formulations used to make the sensors reveals that the formulation used to make sensor 1 produces a nanotube structure while the formulation used to produce sensor two results in a polycrystalline coating. From this comparison is seems reasonable to conclude that PVP is necessary for the formation of nanotubes with mM-β-DMCD. Perhaps the guest-host interaction between PVP and mM-β-DMCD promotes aligning of the CD cone to form nanotubes.
In making a comparison of the STM image of FIG. 4 to the SEM image of FIG. 6 it should be borne in mind that both films were made using the by three component formulation. The only difference is the proportion of each of the components within the formulation. Solutions of 0.4 mg/mL PVP, 2.3 mg/mL PEG and 2 mg/mL cyclodextrin were prepared as described above. For the STM image these solutions were mixed in a 5:2:10 (v/v) ratio and for the SEM image the solutions were mixed in a 3:2:12 (v/v) ratio.
The STM image reveals a denser packing of the nanotubes than that of the SEM in FIG. 6 . Thus, the density of packing of the nanotube structure can be controlled by varying the proportions of the components. The same effect was seen in the two component system.
Several different proportions were tried for the for two-component system, but none had tube structure imaged by SEM. However, after adding PVP to the two-component solution, nanotubes were formed regardless of changing the proportion.
EXAMPLE 3
Molecular Recognition
Cyclic voltammetry (CV) was used to study the unique features of the BMZ sensors and to evaluate feasibility in a preliminary study. The study revealed that mM-β-DMCD enhances current from NPA even in presence of NPO − in a homogenous buffer solution. In an expanded study, BMZ sensors were constructed by using PEG and mM-β-DMCD to coat gold, silver and GC electrodes.
The coated electrodes were used to obtain CV voltammograms and the results were compared with one another.
The various electrode materials resulted in the production of BMZ sensors having differing response characteristics. The differences between the BMZ/GC, BMZ/gold and BMZ/silver sensors are (1) the BMZ/GC sensor has fast response time, (2) the BMZ/gold sensor and BMZ/silver sensor provided oxidation-reduction peaks within the scan range from −0.8 to 0.8 V, and the peaks showed a degree of irreversibility. In contrast, the BMZ/GC electrode showed only one intense reduction peak that was predominately irreversible. The degree of molecular recognition of o-NPA among other isomers for the three BMZ sensors were in the order of GC>silver>gold. Therefore, GC electrodes were used for a detailed analysis of the ability of the BMZ electrodes to distinguish among the three isomers of NPA. There was no significant peak change in the CV profiles of o-NPA using the bare electrode through consecutive scans. The m-NPA and p-NPA have CV profiles similar to that of o-NPA. This indicates that the bare electrode has no molecular recognition, nor differences in catalytic behaviors toward the three structural isomers.
Initially, consecutive CV scans were applied to two BMZ/GC sensors, sensor 1 with three-component fabrication, and sensor 2 with two-component fabrication, in order to: (1) find whether or not there is a positive correlation between the cathodic currents and time, (2) find the right polarizing potential to measure the cathodic current (3) find the appropriate data acquisition rate for an amperometric method. An attempt was made to find the steady-state current. Cyclic voltammograms were obtained using the BMZ sensor in order to test for the molecular recognition of the various isomers of NPA. The tests were conducted in pH 9.87, 0.067 mol/L buffer solution with 0.10 M KCl at 25.0° C. FIG. 7 shows the results obtained with a glassy carbon (GC) electrode fabricated with mM-β-DMCD, PEG and PVP. Panel A shows the results obtained without (dotted curve a) and with 2.0×10 −4 mol/L o-NPA. The solid curves b-f were with o-NPA in consecutive scans (scan rate 20 mV/s). Panel B shows the results obtained without (dotted curve a) and with 2.0×10 −4 mol/L p-NPA. The solid curves b-f were obtained in consecutive scans as above. Panel C shows the results obtained without (dotted curve a) and with 2.0×10 −4 mol/L m-NPA 2.0×10 −4 mol/L. The solid curves b-f were from consecutive scans as above. The reference electrode is Ag/AgCl, and Pt is the auxiliary electrode. Panel D shows the results obtained with the bare electrode and o-NPA. Under identical experimental conditions, the BMZ sensor 1 responses to o-NPA were enhanced (FIG. 7) by comparison with the bare electrode.
The o-NPA has the highest catalytic peak as shown in FIG. 7 . The CVs for all three isomers show the current decreases as the number of consecutive CV scans increase. By plotting the peak current vs CV scan from 80 to 640 s (1-8 scans), a negative correlation for each of the three isomers was found between peak current and the elapsed time. Those skilled in the art appreciate that it is common for the initial CV scans to be different from subsequence scans and these are often ignored in analytical determinations. Scans 3-5 appear to represent a steady-state response with CV. An exponential decay curve was observed for each isomer, data is not shown.
These observations suggested (1) the sensor has very fast response time and the peak limiting current at steady-state may not be seen at the scan rate used. (2) It is appropriate to use an amperometric method to evaluate the performance of the BMZ sensors quantitatively. A well-defined catalytic reduction peak for the o-NPA is obtained at −0.68 V as shown in FIG. 7 . From FIG. 7, we can conclude that this sensor indeed selectively favors the o-NPA rather than meta and para isomers. The special recognition for ortho isomer also confirmed with other BMZ electrodes described earlier in this section. Sensors prepared with two components showed a similar trend for molecular recognition.
By comparison with sensor 2 shown in FIG. 8, it is clear, that sensor 1 has drastically reduced the background current by 2.5-fold. FIG. 8 shows a cyclic voltammogram with and without 2.0×10 −4 mol/L o-NPA in 0.067 mol/L, pH 9.87 buffer with 0.10 M KCl at 25.0° C. The GC electrode was fabricated with mM-β-DMCD and PEG only. The dotted curve is for blank as (a). The solid curves are with o-NPA using consecutive scans as (b-g). The scan rate was 20 mV/s. Comparison of FIGS. 7 and 8 reveals that sensor 1 produces 30% more peak current than produced by sensor 2. This observation has been confirmed amperometrically.
The sensors successfully demonstrate well-defined, single electrocatalytic peaks for the three isomers. The sensors do not oxidize the hydrolysis product NPO- − within the scan range employed, so the problem of fouling of the electrode can be avoided. Sensor 1 has good coverage of 3×10 19 molecule/cm 2 , based on the equation of Γ=Q/nFA, Γ is the surface coverage, Q is the charge, n is the number of electrons, F is the Faraday constant and the A is the sensor conducting area. By subtracting the charge from the bare electrode response to the analyte, the net charge will be the contribution from the electrocatalytic reaction.
Since a well-defined electrocatalytic peak was obtained and the applied potential is also known, it is advantageous to make amperometric measurements. Plots of current vs. time for the three isomers using either sensor 1 or 2 confirms that the magnitude of the amperometric current among the three isomers is in the order of o-NPA>m-NPA>p-NPA, but the order is reversed for the rate constants.
Both sensors are capable of detecting o-NPA, based on their well-defined catalytic reduction currents sensor 1 being somewhat more effective than sensor 2. PVP enhanced the biosensor performance perhaps by permitting the formation of nanotube structures. The novelty of this fabrication technology is to form a firm smooth co-polymer network of catalytically active cyclodextrin cross-linked with PVP through the PEG. This unique approach minimizes formation of pin-holes in the membrane.
The three component system acts as an electron barrier to o-NPO − as shown in FIG. 9 which shows a cyclic voltammogram with and without 4.80×10 −4 mol/L o-NPO − in 0.067 mol/L, pH 9.87 buffer with 0.10 M KCl at 25.0° C. The GC electrode was fabricated with mM-β-DMCD and PEG and PVP. The bare GC electrode responses to o-NPO − is shown by the dotted curve, and the BMZ/GC electrode responses to o-NPO − with the solid curve. The immobilized three-component monolayer has suppressed the permeation of the o-NPO − ions to the electrode. The suppressed peak is more irreversible than that of bare electrode, and the background current has been remarkably reduced by the membrane. This observation is consistent with the literature (Chung 1990).
EXAMPLE 4
Supramolecular Channel Amplification
Supramolecular channel devices were defined as structurally organized and functionally integrated chemical systems built into supramolecular architectures by Jean-Marie Lehn (Lehn 1985). Current progress in the construction and characterization of supramolecular devices has been reported ( Proceedings of the NATO Advanced Research Workshop on Chemosensors of Ion and Molecular Recognition , Kluwer Academic Publishers, Bonas, France, 1997; Editors Scheller, F. W., Schubert, F., Fedrowitz, J., Frontiers in Bosensorics , books one and two, Birkh-user Verlag Base, Boston, 1997; Szejtli et al. 1996). Molecular recognition and amplification are the two distinguishing features of supramolecular channel devices. Evaluation of the amplification effect of the new developed BMZ sensor is done based on evaluation of the signal to noise ratio (S/N), and the rate constants of the electrochemical reactions.
As shown in FIG. 4, the three component coating of the present invention spontaneously forms nanotube structures. Amperometric response curves are shown in FIGS. 10 and 11. These figures show amperometric time-dependent response curves with and without surface immobilization at pH 7.20, 0.067 mol/L buffer with 0.10 M KCl, 25.0° C. In FIG. 10, (a) represents the response curve of the BMZ/GC sensor 1 (i.e., mM-β-DMCD+PEG+PVP) to 0.48 mmol/L of o-NPA in pH 7.2 solution, (b) represents the sensor 1 response curve to 0.48 mmol/L of o-NPO − , and (c) is the bare electrode responses to 0.48 mmol/L of o-NPO − . In FIG. 11, (a) and (c) are the same as (a) and (c) of FIG. 10, and (b) is the bare GC electrode response to o-NPA. These figures clearly illustrate that the bare electrode produces high noise and weak signal. In contract, the BMZ sensor has 30-fold increase in the S/N ratio by comparison with bare electrode as illustrated in FIG. 10 between (a) and (c). This demonstrates the ability of the BMZ sensor to enhance the signal and reduce the noise based upon its electrocatalysis. Comparing (a) and (b) in FIG. 10, the BMZ sensor of the present invention responds to o-NPA and o-NPO − very differently, even under same conditions. This is also seen by comparison of the CV voltammograms of the BMZ sensor 1 response to o-NPA in FIG. 7 to the response of the sensor to o-NPO − as shown in FIG. 9 . The responses to o-NPA and o-NPO − were totally different. We are unable to explain the drastically different responses in terms of electrochemical mechanisms explicitly without further experiments.
An experiment was conducted by simultaneously measuring UV absorbance of NPO − and amperometric current under an applied potential using sensor 1. Here sensor 1 serves as an electro-optical sensor. The colorless solutions very quickly changed to yellowish color after injecting the NPA analyte or phenyl acetate. The UV absorbance of NPO − is enhanced, as is the initial rate of formation of NPO − , as measured as the change of absorbance vs time, compared with a GC bare electrode. This indicates that hydrolysis of the ester occurred, and mM-β-DMCD catalyzed the hydrolysis reactions heterogeneously. This demonstrates that sensor 1 may be used as an electro-optical probe.
Without wishing to be bound by the theory, it is hypothesized that the nanotubes with more than 20 CDs lay on the surface of the electrode and become an organic electronic conductor. The organic electron conductor serves to transfer electrons to the electrode surface when the catalysis reaction occurs. Recently, Dagani reported in C&EN about the electronic applications of carbon nanotubes (Dagani 1998). Formation of nanotubes can lead to a major changes in the electronic properties of CDs allowing them to serve as microelectronic devices. The nanotubes functioning as electronic channels promoting electron flow may explain why the response time is so fast. The first-order rate constants for the electrocatalytic reaction are 0.31 s −1 and 0.19 s −1 for sensor 1 and sensor 2 at pH 9.87, 25.0° C., respectively. This evidence clearly demonstrated that the sensor 1 has supramolecular channel amplification effect, that sensor 1 not only improved the sensitivity by 31% compared with sensor 2 described in next section, but also improved the rate constant. Perhaps the nanotube packing facilities the electron transfer, hence overall rate is increased. In contrast, sensor 2 does not have PVP, therefore nanotube structure is not likely, because PEG does not contain an aromatic ring and lacks hydrophobicity. According to Li's report, a compound with an aromatic ring is necessary to form nanotubes with CDs (Li et al., Science 1994).
In the absence of catalytic effects, the BMZ sensor only improves the S/N ratio by 4.7 times and slightly improves the signal intensity for o-NPO 31 . This is seen by comparing the response of the BMZ sensor to o-NPO − ((b) in FIG. 10) to the response of the bare electrode to o-NPO − ((c) in FIG. 10 ). The bare electrode can detect o-NPA with a very small S/N ratio, as shown in FIG. 11 ( b ).
EXAMPLE 5
Response Curves
FIG. 12 illustrates a typical set of time dependent amperometric response curves for measuring o-NPA with sensor 1 fabricated with three components. The data was obtained at different concentrations of o-NPA in pH 9.87 buffer solution with 0.10 M KCl, at 25.0° C. The concentrations were as follows from a to g: o-NPA(mmol/L) 2.86, 1.90, 1.43, 0.48, 0.38, 0.19, 0.00. Experimental data( . . . ), Fitted data (—).
All response curves approach steady-state monotonically. The dotted curves are the experimental data, and the solid curves are the fitted data by using a predictive curve fitting method to fit a first-order model to 0-40 s data. The predictive curve fitting method is to fit a suitable mathematical model to the transient data and then to predict the steady-state signal, if the signal reaches a steady-state (Chen et al. 1993; Pardue 1989; Williams et al. 1996; Lim et al. 1996; Wang et al. 1997). The pseudo first-order rate constants for the approach to steady state at different concentrations were constant at 0.31/s, this strongly suggests that the sensor's fast responses are not concentration dependent. This is truly an advantage for practical applications, and also overcomes the drawbacks of the response time depending on the analyte concentration as for an amperometric phenolic sensor made with the natural enzyme (Kotte et al. 1995).
EXAMPLE 6
Sensitivity
As shown above, utilizing the catalysis of modified CD and self-assembly of three-component fabrication enabled the detection of NPA esters in a more convenient way than those methods of the prior art. An important distinction between the present invention and those methods and devices of the prior art is that the present invention does not require a mediator molecule. As a result, no loss of signal due to the inefficiency of the coupling reaction is seen. In addition, the bioselectivity of catalytically active cyclodextrins overcomes the interference between isomers. Finally, the response of the present invention is rapid compared to those methods of the prior art; the half-life for the electrochemical detection is 2 s.
The sensor of the present invention has a linear response over the range tested. FIG. 13 shows the calibration plot of the measured amperometric current vs. concentrations of o-NPA for the BMZ sensor 1. FIG. 13 demonstrates that the sensor has good linearity for sensor 1.
The sensitivity results for comparing with two sensors were shown at first column of slope in Table 1.
TABLE I
Least-squares statistics for measured current vs. concentrations
of o-NPA for BMZ sensors with different fabrications a
Correla-
Slope b
Intercept
Std. Error
tion
Pooled
(μA/mmol/L)
(mmol/L)
of
Coeffi-
Std.
Std.
Std.
Estimate
cient
Dev. c
Value
Dev.
Value
Dev.
(mmol/L)
(r)
(mmol/L)
(Sensor I d )
102.1
2.83
0.078
0.043
0.113
0.9970
0.0953
(Sensor
II c )
78.0
3.90
0.147
0.049
0.130
0.9915
0.1295
a the unit for intercept, standard error of estimate and poled standard deviation was expressed in mmol/L, based on the values of each item divided by the value of slope, in order to facilitate the comparison.
b refers to the sensitivity on a total area of 0.07 cm 2 BMZ electrode.
c Three replicate runs on each of six concentrations in the linear range of 0.190 to 2.86 mmol/L for sensor 1. The currents are within 24.5 to 350 μA. Three replicate runs on each of five concentrations in the linear range of 0.0952 to 1.90 mmol/L for sensor 2. The currents are within 15.5 to 170 μA. Both sensors averaged 30 points of the steady-state current from 30 to 60 seconds. The reactions were monitored for 0 to 200s.
d Uses three-component fabricaton of the BMZ sensor.
e Uses two-component fabricaton of the BMZ sensor.
The slope shows the sensitivity for measured current vs. concentrations at a 0.07 cm 2 BMZ/GC electrode. The sensitivity has increased from 1.11±0.04 A L/mol cm 2 (78 μA/mmol/L/0.07 cm 2 ) for the sensor 2 to 1.46±0.04 A L/mol cm 2 (102.1 μA/mmol/L/0.07 cm 2 ) for the sensor 1. The 31% increase in sensitivity confirms the advantage of using the three-component fabrication technique with the nanotube arrangement. This novel BMZ sensor also demonstrates an increasing sensitivity by 4 to 6 fold compared with Kotte's (Kotte et al. 1995) sensors, and 14-fold compared with Luong's glucose sensor (Zhao et al. 1993). A 280-fold enhanced sensitivity compared with Liu's glucose amperometric sensor made with cyclodextrin polymer (Liu et al. 1998).
The two BMZ sensors demonstrate the capability to detect o-NPA in a linear range from 0.0952 to 1.90 mmol/L for sensor 2, from 0.19 to 2.86 mmol/L for sensor 1. Sensor 1 has negligible systematic error as shown by the negligible intercept in Table 1, the intercept for sensor 2 was not negligible according to a 2-tail t-test at 95% confidence level with P<0.001.
Imprecision
Biosensors, especially BMZ sensors, often suffer low precision. There are very few, if any, attempts in the prior art to create a highly reproducible BMZ sensor (Bucke et al 1998). The prior art recognizes that many difficulties are encountered during the development of BMZ biosensors. Likewise, the development of CD-based sensors that possess bio-recognition and reproducibility has been an equally unattainable goal. The present invention has achieved unexpectedly precise results as shown by the data in Table 1. The last column in Table 1 included the pooled standard deviations for the sensors for three replicates at each of six, and five concentrations, for sensor 1 and 2, respectively. The pooled standard deviations were 95.3 μmol/L (n=18), and 129.5 μmol/L (n=15), corresponding to relative standard deviations of 5.6 and 9.9% for signals at average concentrations for sensor 1 and 2, respectively.
Stability
The stability of the steady-state currents measured by the BMZ sensor was not dependent on analyte concentrations as shown in FIG. 12 . In other words, when the current reaches a steady-state, its magnitude remained constant regardless of the analyte concentration used. This demonstrated the utility of the sensors. The operational stability has been investigated by using the amperometric method to measure o-NPA at 1.92 mmol/L concentration at pH 7.2, 25.0° C. for a period of 2.5 months and the results are shown in FIG. 14 . Sensor 1 was quite stable under the operating conditions tested. The signal intensity had no significant drift, only 0.2%/day drift over 42 days, while the sensor has performed 68 measurements with different assays over that period. After 42 days, the rate of the signal drift increased slightly to 0.58 μA/day. Overall, the signal decreases less than 0.3%/day compared to the initial signal. Over 2.5 months, sensor 1 made 96 measurements with only a 17.7% loss in signal, and 10.7% loss in signal after two months with 80 measurements. By way of comparison to BMZ sensors of the prior art, Liu's sensor lost 14% of its original activity while in storage for: two months. It should be noted that the sensor did not make measurements during this period (Liu et al. 1999). The operational stability of the BMZ sensor is superior to the sensor made with natural enzyme that lost 30.8% of its initial response after 96 assays (Wang et al. 1997). Thus, the sensor of the present invention is unexpectedly superior instability to those of the prior art.
Effect of pH
The pH effects on first-order rate constant were determined and the response currents were included in Table 2.
TABLE II
The pH effects on the measurement objectives based
on the amperometric biomimetic sensor
9.87
8.20
7.20
6.50
pH
Value (Std. Dev.)
RSD (%)
I x (mA)
0.31(0.02)
0.33(0.08)
0.36(0.03)
0.34(0.01)
6.1
k p s −1 )
0.31(0.02)
0.30(0.02)
0.30(0.04)
0.29(0.02)
2.7
I x was obtained by an average of 30 points of the steady-state cathodic current.
k p was obtained by using a predictive multiple curve fitting method to a first-order model. The data of the rate constant were for triplicate runs. The concentration of o-NPA was 2.86 mmol/L for rate constant and current measurement at 25.0° C. The buffer concentration was 0.067 mol/L with 0.10 M potassium chloride.
The second row is the steady-state current with different pH. The current has a relative standard deviation (RSD)of ±6% of the average current from the pH range 6.50 to 9.87 at 25.0° C. This is an obvious advantage of the biomimetic enzyme over the natural enzyme. The third row is for the first-order rate constants using a predictive curve fitting method averaged for triplicate runs. The pH has even less influence on the rate constants than the current, without consideration of the current effects, only a RSD value (%) of ±2.7% error related to the average rate constant. The total error, including current effects=±(RSD 2 current +RSD 2 rate ) ½ (Ross et al. 1998). This unexpected feature of insensitivity to pH enhances potential applications of BMZ sensor.
Effect of Temperature
The effect of temperature on the rate constant and current has been studied. A temperature decrease from 25.0° C. to 0.0° C. decreases the rate constants about ten times at pH 7.20 for isomers at 2.86 mmol/L concentration. This corresponds to a 0.011 s −1 /° C. decrease. This effect was similar for all three isomers. The steady-state current intensity was less effected by comparison with the effect of pH. Values of 1.2, 0.5 and 0.6%/° C. decrease in the signal intensity for o-, m- and p-NPA isomers from 25.0 to 0.0° C. has been observed. For natural enzymes, for example tyrosinase, when the temperature is lower than 10° C., the sensor becomes dysfunctional, because the enzyme activity decreases to less than 50% of the initial activity (Wang et al. 1997). Obviously, the BMZ sensor of the present invention has improved operational characteristics compared to the sensors of the prior art.
The sensor of the present invention has demonstrated a number of unexpected and unique features as compared to those sensors of the prior art. One feature of the present invention that is unique is the catalytic activity of the cyclodextrins used. This permits the construction of a sensor that does not require the presence of a mediator. In addition, only 2.3 ng of mM-β-DMCD is needed for fabrication of a BMZ/CD sensor. The sensor of the present invention provides specific molecular recognition of o-NPA over other structural isomers leading to reduced interference. The unique molecular structure of the present invention results in a sensor with a very fast response time that is not dependent on the analyte concentrations. This overcomes one of the major problems with the immobilized enzyme based sensors of the prior art. The BMZ sensor significantly improved the S/N by 30-fold compared with bare electrode and it acts as a molecular channel amplifier. The well-defined BMZ/CD sensor system has negligible systematic error. The sensors of the present invention are less affected by pH and temperature; hence, these features made them superior to sensors made with natural enzyme.
EXAMPLE 7
Applications of the Present Invention
The present invention will find use in the analysis of samples in order to detect the presence of toxic chemicals. The samples may be derived from any source including, but not limited to, environmental sources, such as bodies of water, soil samples and the like. When the samples are solid, an extraction process may be necessary to place the toxic materials in solution or suspension in order to facilitate their detection. The samples may be derived from industrial sources including but not limited to, waste streams, reagent streams, reactors and the like. The sensors of the present invention may used in an industrial setting to monitor the course or progress of a synthetic reaction. The present invention may be used to analyze samples derived from a clinical setting including, but not limited to body fluids and the like. In a preferred embodiment, the sensors of the present invention will be incorporated into a micro device to be used in flow systems and will enable detection of even lower levels of toxic chemicals. Such a portable micro-chip device may be used to detect low levels of toxic chemicals ingested by humans and animals, for example, aspirin and salicylic acid overdoses in children. The construction of such a micro device incorporating the sensors of the present invention is well within the ambit of ordinary skill in the art (Wang 1997; Biosensors and Electronic Noses, Kres-Roger, Editor, 1997).
The present invention has been described making use of certain, non-limiting examples. One skilled in the art can easily ascertain the essential characteristics of the present invention from these examples and, without deviating from the spirit and scope thereof, can make changes and modifications to adapt the invention to various uses and conditions. Such changes and modifications are deemed to be within the scope of the present invention as defined by the appended claims. All references cited are specifically incorporated herein in their entirety.
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The present invention provides a novel biosensor for the detection of chemicals of interest. The novel biosensor of the present invention comprises an electrode having a catalytically active cyclodextrin attached thereto. The present invention will be useful for the detection of materials in a wide variety of samples. In particular, the present invention will permit the detection of nitrophenyl esters.
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[0001] This is a continuation of U.S. patent application Ser. No. 09/536,554, filed Mar. 28, 2000.
BACKGROUND OF THE INVENTION
[0002] The present application relates to throttle bodies for intake manifolds of a spark ignition internal combustion engine. More specifically, the present invention relates to an intake manifold for a spark ignition internal combustion engine that has an integrally molded plate, shaft and lever assembly.
[0003] In the past, there has been a need for easy to assemble, lightweight and more reasonably priced components for fuel injected engines which require a throttle body. In the past, throttle bodies have typically been configured as a one-piece housing in which a plate, shaft and lever assembly were assembled in separate pieces of a housing. Typically, because of the one-piece construction of the housing, a somewhat time consuming assembly process was necessary in order to pivotally secure the plate member inside of the throttle body bore and thereafter connect the peripheral portions and/or control inputs along the shaft.
[0004] Thus, in typical prior art constructions, a multi-step process was required for pressing bearings and then installing the shaft, springs, and lever assembly and the like. Typically with such constructions, the throttle control spring was inboard of the throttle lever assembly. Additionally, the throttle lever assembly, shaft and plate were all separate pieces which needed to be connected by way of rivets or the like in order to provide a finished throttle body for installation on an engine. As might be readily appreciated, most of these parts have been made from metal, which is heavy, and the steps necessary to assembly the throttle body made such units relatively expensive components of the vehicle engine.
[0005] In recent years, there have been some advances in throttle body designs, such as providing a two-piece assembly. A two-piece throttle body makes it easier to install the plate member. However, there remains a need for making an inexpensive yet reliable throttle body housing.
SUMMARY OF THE INVENTION
[0006] In accordance with the present invention, there is provided a throttle body assembly for an engine, which includes a throttle body housing having a central intake bore therethrough. In the present invention, a throttle plate member is rotatably disposed in said bore for metering air flow through the throttle body and to the engine. The throttle plate member of the present invention includes a shaft member, which is effective for pivoting the plate member about an axis. In the present invention, the throttle plate member and the shaft and lever assembly and the like are integrally formed by one-piece injection molding and installed in the throttle body as a single piece.
[0007] Further understanding of the present invention will be had by reference to the detailed description of the preferred embodiments set forth below when taken in conjunction with the examples and claims appended hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The various advantages of the present invention will become apparent to one skilled in the art by reading the following specification and subjoined claims and by referencing the following drawings in which:
[0009] [0009]FIG. 1 is a perspective view of an engine utilizing a throttle body in accordance with the present invention;
[0010] [0010]FIG. 2 is a detailed perspective view of a throttle body in accordance with the present invention;
[0011] [0011]FIG. 3 is an exploded perspective view of the throttle body of the present invention;
[0012] [0012]FIG. 4 is a section taken along line 4 - 4 of FIG. 3;
[0013] [0013]FIG. 5 is a section of an alternate embodiment of the plate, shaft and lever assembly of FIG. 3; and
[0014] [0014]FIG. 6 is a detailed broken away perspective view of a connection assembly for the throttle body taken along line 6 - 6 of FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] In accordance with the present invention, there is provided a throttle body generally shown at 10 for use on an engine 12 of a vehicle 14 . Particular throttle bodies are typically used for attachment to an intake manifold 16 of a fuel injected engine. The throttle body of the present invention is unique in that it is entirely produced from injection molded portions. The throttle body of the present invention includes a throttle body housing generally indicated at 18 . The throttle body 18 includes a central intake bore 20 therethrough. The throttle body of the present application includes an upper throttle body member 22 (air intake portion), a throttle plate, shaft, and lever assembly member 24 , and a lower throttle body member 26 (air discharge portion). The throttle plate, shaft, and lever assembly member 24 is rotatably disposed in the bore 20 for metering of air flow through the throttle body, and thus controlling engine speed.
[0016] The throttle plate, shaft, and lever assembly member 24 of the present invention is different form prior art devices in that it is a one-piece integrally molded assembly, such as shown in FIGS. 4 and 5. Prior throttle body designs required assembly of the throttle plate assembly and shaft in the throttle body after casting of the throttle body. This is labor intensive and the metal used in the castings adds undesirable weight to the vehicle.
[0017] The throttle plate, shaft and lever assembly member 24 shown in FIG. 3 includes a central plate portion 28 (as shown in FIG. 4), bearing members 30 and 32 , a throttle cable connection portion 34 , and a position sensor end 36 . The plate member is thick in the center portion 38 and tapers outward to edge portions 40 and 42 . A series of strengthening ribs 44 is provided on the upper and lower surfaces of the plate member. The profile of these ribs also provides improved air flow over the plate surfaces, for increasing engine performance. However, other strengthening ribs or the like may be included for strengthening of the throttle plate.
[0018] The throttle position sensor end engages the throttle position sensor 46 for sensing the position of the throttle plate, shaft, and lever assembly member 24 . The cable end 34 (or lever) connects to a cable 48 for throttle control of the throttle plate, shaft, and lever assembly member 24 . The cable end 34 includes a spring retaining shaft. The throttle return springs 52 and 54 engage the shaft 50 and are positioned by the spring positioning arm 56 . Cable end 34 is outboard of the bearings 30 and 32 , which provides an efficient assembly of the cable 48 to the plate assembly 24 . This also allows for the throttle return springs 52 and 54 to be installed on the outside of the assembly 24 , further streamlining the assembly process.
[0019] Lower throttle body member 26 also includes an air idle bypass chamber 27 , which is connected to an air source in the clean side of the air filter. Idle bypasses are known and typically are operably connected to a control valve that controls a linear solenoid or stepper motor for positioning of the bypass control valve at idle. The present invention differs from prior art designs in that the reference air source is taken from the clean side of the air cleaner rather than directly from the throttle body inlet.
[0020] Upon assembly, the bearings 30 and 32 rest in bearing surfaces 58 and 60 in the lower throttle body member and mating bearing surfaces 62 and 64 in the upper throttle body member. The throttle plate, shaft, and lever assembly member 24 is positioned between the upper and lower body members, and they are brought together and temporarily secured in place via clip or snap fit tab assemblies 66 , which are shown in more detail in FIG. 6. Bearing members are preferably integrally molded with the plate assembly. Alternatively, ball bearings may be used in their place. For instance, a sealed ball bearing unit could be overmolded into the throttle plate, shaft, and lever assembly member 24 .
[0021] Each clip assembly 66 includes a spring arm 68 , which engages a ledge 70 during engagement of the two halves of the throttle body. This provides for assembly during shipping of the assembled throttle body. Bolt holes 78 are provided for final attachment of the throttle body into the intake manifold. The upper throttle body member 22 includes a concentric lip 72 , which fits in a portion 74 of lower throttle body member 26 . A seal 76 is provided around the perimeter other than at the bearing areas for sealing the throttle body opening.
[0022] Upper throttle body member 22 is preferably produced from an injection moldable material which will allow strict tolerances to be maintained it the position where the edges 40 and 42 are located during the idle position (i.e., where the throttle plate, shaft, and lever assembly member 24 is substantially horizontal). In order to maintain the position, the edges 40 and 42 are positioned adjacent the lip 72 . Lip 72 is, in fact, designed with a reduced thickness at this location to ensure roundness and proper tolerances between the lip 72 and throttle plate edges 40 and 42 during molding. Materials used for the upper throttle body are preferably engineering resins such as glass reinforced polyether amide resins. A preferred resin is a 30% glass reinforced resin sold under the name ULTEM 2310, available from GE Plastics of Pittsfield, Mass.
[0023] Typically, the throttle plate, shaft, and lever assembly member 24 may also be injection molded from an engineering resin such as a polythalamide, or preferably glass-filled polythalamide. A preferred resin is an AMODEL glass reinforced resin, such as A-1145 HS, available from B.P. Amoco Chemicals, having offices in Livonia, Mich. As shown in FIG. 5, the material can be overmolded around a steel support shaft 80 as an alternate embodiment for providing added rigidity and strength if necessary.
[0024] Lower throttle body member 26 can be produced from any number of materials. Preferably, a strong inexpensive material such as nylon or the like can be used. Certainly, engineering resins would equally be useful for this component. In an alternate embodiment, the lower throttle body member 26 could also be manufactured as a part of the manifold. In this embodiment, the throttle plate, shaft, and lever assembly member 24 and upper throttle body 22 and other components would be installed in place on the manifold 16 , having the lower throttle body member 26 as an integral part. Alternatively, the upper throttle body 22 could be an integral part of the manifold 16 while the lower throttle body 26 and the throttle plate, shaft and lever assembly member 24 would be installed in place on the manifold 16 .
[0025] Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited such other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification and following claims.
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The subject invention is a throttle body for an intake manifold of a spark ignition internal combustion engine. The throttle body includes a throttle plate member comprising a shaft, a throttle plate and a lever. The throttle plate member is integrally molded as one piece from an engineering resin. The throttle body also includes an air intake portion and an air discharge portion. Either the air intake or the air discharge portions may be integrally attached to the intake manifold prior to assembly of the throttle plate member.
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FIELD OF THE INVENTION
The present invention relates to a striping apparatus of a knitting machine, particularly to a striping apparatus of a circular knitting machine.
BACKGROUND OF THE INVENTION
There are striping apparatus technologies of circular knitting machines well known to people, such as U.S. Pat. No. 6,655,176 “Striping Apparatus For Circular Knitting Machines” and U.S. Pat. No. 5,070,709 “Striping System For Circular Knitting Machine”, which respectively disclose striping apparatuses feeding different yarn into the knitting needle of a knitting machine. Besides, U.S. Pat. No. 5,218,845 “Circular Knitting Machine Striper Control System” discloses a controller for a striping apparatus.
As shown in from FIG. 1A to FIG. 1D , the striper structure of the abovementioned U.S. Pat. No. 5,218,845 comprises: yarn-changing plates 10 ; movable blades 11 ; and drive elements (not shown in the drawings), used to drive the yarn-changing plates 10 and the movable blades 11 . In normal state, the yarn-changing plate 10 is at a non-enable normal position, and the movable blade 11 also withdraws back to the main body 12 , and a hook 110 clips the yarn to position at the front edge 120 of the main body 12 . As shown in FIG. 1B , when the machine begins to feed yarns, the drive element pushes the yarn-changing plate 10 , and then, the front end of the yarn-changing plate 10 extends outward. Simultaneously, the rear end 101 of the yarn-changing plate 10 touches a first pin 111 of the movable blade 11 to drive the movable blade 11 toward the left side of the FIG. 1C until the yarn-changing plate 10 reaches an external yarn-feed position, and then, the hook 110 of the movable blade 11 releases a yarn Y, as shown in FIG. 1C . Naturally, before the hook 110 releases the yarn Y, the yarn-changing plate 10 has transferred the yarn Y to the yarn-feed position, and a knitting needle 13 hooks the yarn Y to perform knitting operation.
Lastly, when yarn is intended to change, the yarn-changing plate 10 , which has reached the external yarn-feed position beforehand, will be pulled by the drive element back to the normal position, as shown in FIG. 1A . During the process that the yarn-changing plate 10 moves to the right side of FIG. 1D , a nose 102 of the yarn-changing plate 10 will touch a second pin 112 of the movable blade 11 and actuate the movable blade 11 to move rightward and back to the normal position, and then, the hook 110 of the movable blade 11 will cut off the yarn Y and clip the tail of the yarn Y at the front edge 120 of the main body 12 .
In general, such a striping apparatus can provide multiple different colors of yarns; for example, the four-color striping apparatus has four sets of parallel-arranged yarn-changing plates 10 and movable blades 11 to change four kinds of yarns respectively, and it is the same for the six-color striping apparatus; the more the number of yarns, the greater the width of the striping apparatus. In the striping apparatus disclosed in the abovementioned U.S. Pat. No. 5,218,845, as the movable blade 11 is driven by the yarn-changing plate 10 , the time that the yarn-changing plate 10 touches the second pin 112 of the movable blade 11 is later than the time that the drive element begins pushing the yarn-changing plate 10 toward the normal position. Such a design that both the yarn-changing plate 10 and the movable blade 11 are driven by an identical drive element will bring about the delay of the time that the movable plate 11 cuts off the yarn Y. In such a design that both the yarn-changing plate 10 and the movable blade 11 are driven by an identical drive element, when an old yarn and a new yarn, e.g. a yarn 1 and a yarn 6 , are spaced farther, the time difference between two actions increases because of the larger spacing therebetween, and the time of releasing the yarn Y is too late so that the yarn will be torn off when the tail of the yarn is still clipped by the movable blade 11 and a yarnlet Y 1 will still remain clipped, as shown in FIG. 1B ; then, the yarnlet Y 1 will be released and tangled with fabric; therefore, fabric quality is degraded.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a striping apparatus of a circular knitting machine in order to avoid the appearance of yarnlets and improve fabric quality.
According to one scheme of the present invention, different cams are separately used to drive the yarn-changing plate and the movable blade, and even though a new yarn and an old yarn are farther spaced, the timings of the cams can be adjusted to rapidly withdraw the old yarn and cut it off and to release the tail of the new yarn from the movable blade before it is torn off. Thereby, the present invention can prevent a yarn from being torn off lest yarnlets appear, so that fabric quality can be improved.
The technical contents and preferred embodiments of the present invention are to be described below in detail in cooperation with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A to FIG. 1D are schematic views showing the structure of a conventional striping apparatus and the operation of the yarn-changing plate and the movable blade.
FIG. 2 is a schematic view showing a preferred embodiment of the striping apparatus of the present invention.
FIG. 3 is a schematic view showing a preferred embodiment of the drive unit of the present invention.
FIG. 4A is a schematic view showing the first portion of the yarn-feed unit at the normal position.
FIG. 4B is a schematic view showing the second portion of the yarn-feed unit at the normal holding position.
FIG. 5A , FIG. 5C , FIG. 5E and FIG. 5G are schematic views showing the sequential operational steps of the yarn-changing plate of the striping apparatus of the present invention.
FIG. 5B , FIG. 5D , FIG. 5F and FIG. 5H are schematic views showing the sequential operational steps of the movable blade of the striping apparatus of the present invention.
FIG. 6 is a schematic view showing the relative positions of old yarn, new yarn and the yarn-entering point of the knitting needle when yarn is changed.
FIG. 7 is a schematic view showing a preferred embodiment of the forward cam of the second cam set of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Refer to FIG. 2 . According to one preferred embodiment, the striping apparatus of a circular knitting machine of the present invention comprises: a controller 20 , a yarn-feed unit and a drive unit. The controller 20 is driven by a selector 30 , which rotates around the knitting portion of the circular knitting machine. The selector 30 is a kind of electronic device functioning like cams and having multiple movable elements 31 , which are normally non-enable. Under the control of a control circuit or a central computer, the movable elements 31 can move to a triggering position. When the selector 30 passes the nearby of the controller 20 , the movable elements 30 at the triggering position will actuate corresponding triggers 21 of the controller 20 to move to an enable position.
The controller 20 further comprises: triggers 21 , first safety levers 22 and second safety levers 23 . One end of the first safety lever 22 and one end of the second safety lever 23 are installed to a sideboard 24 with a first pivotal shaft 221 . The trigger 21 has a first end 210 and a second end 211 ; the first end 210 of the trigger 21 has a protrudent return nose 212 ; the portion between the first end 210 and the second end 211 has a second pivotal shaft 213 , and the triggers 21 are installed to the sideboard 24 with the second pivotal shaft 213 ; and the second end 211 of the triggers 21 also has a protrudent second nose 214 . Refer to FIG. 4A and FIG. 4B . When in normal state, the trigger 21 , the first safety lever 22 , and the second safety lever 23 are all at a lock position; the second end 211 of the trigger 21 presses against the first safety lever 22 and the second safety lever 23 . When the first end 210 of the trigger 21 is moved by an external force, it will rotate around the second pivotal shaft 213 to the enable position, and the second end 211 of the trigger 21 will slide into a notch 220 at the top side of the first lever 22 and a notch 230 at the top side of the second lever 23 , which enables the first lever 22 and the second lever 23 swing around the first pivotal shaft 221 upward to an unlock position. The entire controller 20 comprises multiple units, and each unit is formed of one trigger 21 , one first safety lever 22 , and one second safety lever 23 ; those units are parallel arranged into the entire controller 20 . When in normal state, the relationship between the trigger 21 and the first safety lever 22 of the same unit is shown in FIG. 4A , and the relationship between the trigger 21 and the second safety lever 22 of the same unit is shown in FIG. 4B .
The yarn-feed unit is fixedly installed in the perimeter of the circular knitting machine and comprises two portions. The first portion further comprises: yarn-changing plates 40 , first connecting rods 41 , and second connecting rods 42 . The first portion functions to feed a yarn Y to a yarn-entering position. The second port further comprises: movable blades 50 and a driving link 51 . The second port functions to clip the tail of the yarn Y when standby and to cut off an old yarn, so that the old yarn can be released from fabric and the operation can restore standby state. The abovementioned controller 20 is fixedly installed above the yarn-feed unit, and the preferred embodiments of them are described below.
The yarn-changing plates 40 , first connecting rods 41 , and second connecting rods 42 of the first portion interconnect head to tail to form a kind of three-bar linkage. Multiple different colors of yarns Y separately pass different yarn-guiding rings 25 and then pass the through-holes 401 at the front ends of the yarn-changing plates 40 . When in normal state, the first connecting rod 41 is like a seesaw, and the tail end of the first connecting rod 41 is coupled to the head end of the second connecting end 42 ; the upper side of the central portion of the first connecting rod 41 has a protuberance 412 ; the protuberance 412 contacts the bottom side of the first safety lever 22 normally; the upper side of the head end of the first connecting rod 41 has an upward forward-stroke protuberance 410 , and the bottom side of the head end of the first connecting rod 41 has a downward backward-stroke protuberance 411 . The tail end of the second connecting rod 42 is coupled to the tail end of the yarn-changing plate 40 . The second connecting rod 42 functions to transfer the pulling force of the first connecting rod 41 to the yarn-changing plate 40 and transform the pulling motion of the first connecting rod 41 into a motion of another direction in order to actuate the yarn-changing plate 40 to reciprocate between a normal position (shown in FIG. 4A ) and an external position (shown in FIG. 5C ). The first portion further comprises: a first elastic element 43 and a second elastic element 44 ; one end of the first elastic element 43 is fixed to the sideboard 24 , and the other end supports the first connecting rod 41 from the bottom side of the head end of the first connecting rod 41 . As shown in FIG. 5A , when the trigger 21 shifts to the enable position, the upward pressing force of the first elastic element 43 will push the head end of the first connecting rod 42 upward, and the first safety lever 22 will also move to the unlock position simultaneously, so that the forward-stroke protuberance 410 of the first connecting rod 41 rises above the sideboard 24 to a standby position. The second elastic element 44 supports the yarn-changing plate 40 from the bottom side of the yarn-changing plate 40 in order to complement the first elastic element 43 and provide elastic force for the yarn-changing plate 40 .
The tail end of the movable blade 50 is coupled to the tail end of the driving link 51 . The upper side of the central portion of the driving link 51 has a protuberance 512 , which contacts the bottom side of the second safety lever 23 normally. Both sides of the head end of the driving link 51 separately have an upward forward-stroke protuberance 510 and a downward backward-stroke protuberance 511 in order to actuate the movable blade 50 to reciprocate between a normal holding position (shown in FIG. 4B ) and an external release position (shown in FIG. 5D ). The second portion further comprises a third elastic element 52 ; one end of the third elastic element 52 is fixed to the sideboard 24 , and the other side supports the driving link 51 from the bottom side near the head end of the driving link 51 . When the trigger 21 shifts to the enable position (shown in FIG. 5B ), the upward pushing force of the third elastic element 52 will push the head end of the driving link 51 upward, and the second safety lever 23 will also be moved to the unlock position simultaneously, so that the forward-stroke protuberance 510 of the driving link 51 rises above the sideboard 24 to the standby position ready for being pushed out.
The drive unit further comprises: a first cam set 60 , a second cam set 70 , and return cams 80 , and as shown in FIG. 3 , all of them together with the selector 30 are installed to a mount board 90 and rotate around the knitting portion of the circular knitting machine synchronically. The first, second cam sets 60 , 70 respectively have forward cams 61 , 71 and backward cams 62 , 72 . The forward cam 61 of the first cam set 60 is responsible for pushing the yarn-changing plate 40 to the external position; the forward cam 71 of the second cam set 70 is responsible for pushing the movable blade 50 to the external release position; the backward cam 62 of the first cam set 60 is responsible for pulling the yarn-changing plate 40 back to the normal non-enable position; the backward cam 72 of the second cam set 70 is responsible for pulling the movable blade 50 for clipping/cutting yarns back to the normal holding position. When in the holding position, a hook 502 at the front end of the movable blade 50 will clip the tail of the yarn Y to position it at between the hook 502 and the sideboard 24 .
The practical operation is to be described below in cooperation with from FIG. 5A to FIG. 5H .
Firstly, as shown in FIG. 5A , the control circuit or the central computer controls a movable element 31 of the selector 30 to move to a triggering position. When the selector 30 passes the nearby of the controller 20 , the movable element 31 , which has reached the triggering position, will trigger the second nose 214 of the corresponding trigger 21 . The second noses 214 of the triggers 21 are respectively at different heights; therefore, different movable elements 31 of the selector 30 can be used to trigger different second noses 214 of the corresponding triggers 21 separately, so that the corresponding triggers 21 move to the enable positions, and then, the first safety levers 22 move to the unlock positions, so that the forward-stroke protuberance 410 of the first connecting rod 41 rises above the sideboard 24 to the standby position ready for being pushed out. Simultaneously, as shown in FIG. 5B , the forward-stroke protuberance 510 also rises above the sideboard 24 to the standby position ready for being pushed out.
Next, as shown in FIG. 5C , the drive unit moves to the yarn-feed unit, and a first inclined plane 610 of the forward cam 61 of the first cam set 60 touches the forward-stroke protuberance 410 of the first connecting rod 41 to actuate the first connecting rod 41 and the second connecting rod 42 to push the yarn-changing plate 40 to the external position. Further, as shown in FIG. 5D , a first inclined plane 710 of the forward cam 71 of the second cam set 70 touches the forward-stroke protuberance 510 of the driving link 51 to actuate the movable blade 50 to the external release position.
As shown in FIG. 5E , the return cam 80 moves to the controller 20 again, and the front inclined plane 801 of the return cam 80 gradually closes to the return nose 212 of the trigger 21 , and the rear plane 802 of the return cam 80 pushes the trigger 21 to the normal lock position to actuate the backward-stroke protuberance 411 of the first connecting rod 41 to emerge from below the sideboard 24 . Simultaneously, as shown in FIG. 5F , the backward-stroke protuberance 511 of the driving link 51 also emerges from below the sideboard 24 .
Lastly, as shown in FIG. 5G , the drive unit moves to the yarn-feed unit again, and the first inclined plane 620 of the backward cam 62 of the first cam set 60 touches the backward-stroke protuberance 411 of the first connecting rod 41 to actuate the first connecting rod 41 and the second connecting rod 42 to pull the yarn-changing plate 40 back to the normal non-enable position. Further, as shown in FIG. 5H , the first inclined plane 720 of the backward cam 72 of the second cam set 70 also touches the backward-stroke protuberance 511 of the driving link 51 to actuate the driving link 51 to pull the movable blade 50 back to the normal holding position; at this time, the hook 502 at the front end of the movable blade 50 for clipping/cutting yarns will not only clip the tail of the yarn Y to position it at between the hook 502 and the sideboard 24 but also will cut off the yarn Y.
The time difference between the action of the backward cam 62 of the first cam set 60 and the action of the backward cam 72 of the second cam set 70 , i.e. the time difference between that the first inclined plane 620 touches the backward-stroke protuberance 411 and that the first inclined plane 720 touches the backward-stroke protuberance 511 , can be adjusted according to demand. A practical method is installing the backward cams 62 , 72 separately at cam seats 63 , 64 ; such a design can make an old yarn be quickly withdrawn and cut off when striping (changing a yarn) and make the tail of a new yarn be released from the movable blade 50 before the new yarn is torn off lest the yarn be torn off and yarnlets appear; thereby, fabric quality can be improved.
A preferred embodiment of the forward cam 71 of the second cam set 70 show in FIG. 3 is a two-stage cam, which further comprises: a static cam 73 and a movable cam 74 , wherein the first inclined plane 710 is positioned at the front end of the static cam 73 , and the movable cam 74 further has a second inclined plane 730 . The static cam 73 and the movable cam 74 are separately positioned at different heights. The movable cam 74 is fixed to the forward cam 71 with a screw 741 , and after the screw 741 is loosened, the relative position of the movable cam 74 and the static cam 73 can be adjusted. The abovementioned forward-stroke protuberances of the multiple driving links of the yarn-feed unit are also divided into two kinds of forward-stroke protuberances 510 , 510 a , and the forward-stroke protuberance 510 can be pushed by the first inclined plane 710 of the static cam 73 , and the forward-stroke protuberance 510 a can be pushed by the second inclined plane 730 of the movable cam 74 .
Refer to FIG. 6 , wherein the present invention is exemplified by a six-color striping apparatus. Suppose that the old yarn is the yarn 6 and the new yarn is the yarn 1 herein; when the knitting needle moves to the yarn-entering point shown in FIG. 6 , the movable cam 74 can be moved forward to advance the timing that the second inclined plane 730 touches the backward protuberance 511 from time t 1 to time t 2 shown in FIG. 7 lest the old yarn be released by the movable blade 50 too late and the old yarn be torn off.
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The present invention relates to a striping apparatus of a circular knitting machine, comprising: a selector, a controller, a yarn-feed unit, and a drive unit. The yarn-feed unit has two portions; the first portion includes a yarn-changing plate, which feeds a yarn into a yarn-entering position, and the second portion includes a movable blade, which clips the tail of the yarn when standby and cuts off an old yarn so that the old yarn can depart from fabric when changing yarns and the operation can back to the standby state. In the preferred embodiments of the present invention, different cams respectively drive the yarn-changing plate and the movable blade, and even though a new yarn and an old yarn are farther spaced, the timings of the cams can be adjusted to release the tail of new the yarn from the movable blade before it is torn off.
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BACKGROUND OF THE INVENTION
This invention relates to liquid atomizer pumps. In particular, this invention relates to small hand-held, finger-operated dispensers involving pump assemblages as distinguished from pressurized aerosol containers and valves.
Hand-held atomizer pumps are known in the art, e.g., see U.S. Pat. No. 3,159,316. Among the features that are desirable in a hand-held atomizer pump are that the pump be easily primed, that it provide a leak resistant assembly when attached to a container, particularly when the container is subjected to pressure or is stored on its side or inverted. Further, it is desirable to utilize as few parts as possible in the construction of the pump and to keep the parts relatively simple to achieve low cost for the production and assembly of the pump. Another desirable feature is that the pump be permanently attached to the closure member, i.e., cap or ferrule by the pump manufacturer before shipping the pump to the customer. While some of the prior art pumps may possess some of the desirable features set forth above, no one pump is known to possess all of these features. Thus, it can be readily seen that there is a real need for an improved finger-operated spray pump.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a liquid atomizer pump including a compression chamber, a piston slidably located in the compression chamber, a stem slidable in the piston, a seal adapted to abut the piston, and a check valve located in the lower end of the cylinder.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary sectional view showing details of the pump;
FIG. 2 is a fragmentary sectional view of another embodiment of the pump;
FIG. 3 is a sectional view taken along lines 2--2 of FIG. 1;
FIG. 4 is a perspective view of the seal of the pump embodiment of FIG. 1;
FIG. 5 is a fragmentary sectional view of the pump showing the position of the seal as the actuator button begins moving downwardly;
FIG. 6 is a fragmentary partly-sectional view of the pump showing the actuator button in the fully depressed position; and,
FIG. 7 is a fragmentary partly-sectional view of the pump when the actuator button has begun its upward movement.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The atomizer pump of the invention is illustrated in FIGS. 1 thru 7 and includes a compression chamber 16 which has an integral external flange 17 thereon which rests on top of the lip 18a of container 18. A cap or ferrule 20 is affixed to the top of flange 17 by crimping around the lip 18a of container 18 as seen in dotted outline of FIG. 1. An integral annular collar 52 on the tank permits the ferrule to be crimped thereunder to assemble the pump.
Slidably located inside compression chamber 16 is hollow stem 12. At the top of stem 12 is a conventional spray button actuator 10 which includes nozzle 11 for atomizing the liquid pumped from the container 18. The downward movement of stem 12 is limited by the bottom of button 10 striking the top 20a of cap 20. Stem 12 has an exterior shoulder 13 which contacts a U-shaped retaining ring 19 formed at the upper end of cap 20. Retaining ring 19 thus limits the upward movement of stem 12. If desired, the retaining ring can be constructed by rolling under the end of cap 20a to form the retaining ring 19a as shown in FIG. 2.
The lower end 22 of stem 12 has a reduced diameter portion which forms guides 22a which can be seen in FIG. 1 and in cross-section in FIG. 3. Immediately above guides 22a is shoulder 13 which is normally spaced from, but makes contact with, piston 24 when stem 12 is forced downwardly.
Piston 24 is slidably positioned inside compression chamber 16. As can be seen in FIG. 3, piston 24 is circular in cross-section having a central annular, reduced diameter section 25. Above and below the reduced section 25 are annular increased diameter sections 26--26 which contact the inner walls of cylinder 16 to insure a sliding pressure seal therewith. The center of piston 24 has a hollow bore 27 for sliding receipt of the lower end 22 of stem 12. The relative diameters of the lower portion 22 of stem 12 and bore 27 of piston 24 is such that the lower portion 22 of stem 12 will slide inside of piston 24 while snuggly fitting therein.
Located opposite piston 24 in FIG. 1 is vent hole 30 located in the wall of compression chamber 16. Vent hole 30 allows air from outside container 18 to enter the container when button 10 is depressed as described hereinbefore.
Slidingly fitted in the lower end of stem 12 is a seal member generally indicated by the numeral 38 in FIG. 4. Seal 38 includes a middle or base portion 41 which is circular in cross-section and has an upper surface 42 which contacts the bottom of piston 24 to make a pressure seal therewith. Located above middle portion 41 and connected thereto is intermediate portion 50 which has an annular top surface 51 thereon which rests against the bottom of stem 12. At the bottom of seal 38 is a reduced diameter cylindrical section 43 adapted to receive the upper end of coil spring 28. A top center post generally indicated by the numeral 39, projects upwardly from portion 50 and has a series of spaced apart longitudinal projections 40 thereon which form slots 40a. Slots 40a slidably receive guides 22a on the lower end of stem 12 to prevent seal 38 from turning relative to stem 12. In the drawings three projections are shown although a greater or lesser number may be used.
The upper end of coil spring 28 is received on the lower section 43 of seal 38 and presses against the bottom of middle section 41 as can be seen in FIG. 1. The other end of spring 28 presses against the shoulder 45 located at the lower end of the inside of cylinder 16. Beneath the bottom end of spring 28 is a hollow portion 48 for the receipt of ball check valve 32. The upward movement check valve 32 is limited by the lower end of spring 28.
Located below check valve 32 is dip tube 34 which is connected to the lower end of compression chamber 16. Tube 34 conveys liquids from container 18 to compression chamber 16.
The operation of the atomizer of the present invention is shown in FIGS. 5 thru 7. As a downward force is applied to actuator 10, stem 12 is forced downwardly an initial distance forcing shoulder 23 to strike the top portion of piston 24 and forcing the face 41 of seal 38 away from the bottom of piston 24. At this point fluid contained beneath piston 24 begins to move upwardly in the direction indicated by the arrows in FIG. 5 around seal 38 and upward through stem 12 to nozzle 11. At the position shown in FIG. 5, piston 24 has not been forced downward any distance by stem 12.
In FIG. 6, stem 12 has been forced downward to fully compress spring 28. Valve 32 has been closed during the full downward movement of stem 12 due to the pressure on the fluid between piston 24 and valve 22, and fluid has continued to flow as shown by the arrows in FIG. 5. During such time that the depressing movement of the piston assemblage occurs, venting is effected, by which air is permitted to enter the container 18 from the exterior of the atomizer in order to replace the liquid which is being discharged. Such venting action invloves the vent hole 30 in the side of the compression chamber 16, the piston 24, and the loose fit of stem 12 in the stem guide section 19 of the ferrule.
It will be observed in FIG. 6 that piston 24 has been shifted downward to a level below the vent hole 30. In consequence, such vent hole will now have communication with the exterior atmosphere, by virtue of the looseness of the fit between the stem portion 12 and interior of the compression chamber 16, as well as the looseness of the fit between the stem portion 12 and grommet 14. Atmospheric air may enter past such loose fitting parts, into the upper portion of the compression chamber 16 and thence outward through the vent hole 30 to the interior of the container 18.
In FIG. 7 the atomizer pump is shown after the downward force on actuator 10 has been released and the piston and stem are traveling upward. At this point, spring 28 forces stem 12 upward and liquid from tank 18 travels upwardly in tube 34. The liquid forces check valve 32 up, flows therearound, and continues upward through spring 28 into the space beneath piston 24. As soon as the downward force on actuator button 10 is released, spring 28 forces the surface 42 of seal 38 into contact with the bottom of piston 24 thereby preventing any air from entering the inside of compression chamber 16 below the piston. After stem 12 has traveled completely upward, the volume beneath piston 24 and above valve 32 will be filled with liquid. Piston 24 will be opposite vent hole 30 and upper piston surface 26 will be in sealing contact with retaining ring 19, thus blocking the contents of container 18 and preventing any liquid from seeping or leaking past the loose fitting stem 12. Thus, when button 10 is again depressed the fluid within compression chamber 16 will be forced outward through nozzle 11.
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A finger-operated spray pump assembly adapted to maintain a seal against leakage under substantially all conditions normally encountered by the pump. The assembly includes a compression chamber, a piston slidable in the compression chamber, a stem slidable in the piston, and a seal member abutting the piston. The lower end of the valve stem contacts the seal member to open the seal slightly before the piston starts its downstroke. A closure member for the container to be used is permanently attached to the spray pump.
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RELATED APPLICATION DATA
[0001] This application is a continuation of application Ser. No. 09/434,757, filed Nov. 4, 1999 (now U.S. Pat. No. 6,307,949), which is a continuation-in-part of application Ser. No. 09/186,962, filed Nov. 5, 1998, which is a continuation of application Ser. No. 08/649,419, filed May 16, 1996 (now U.S. Pat. 5,862,260), which claims priority to PCT application PCT/US96/06618, filed May 7, 1996.
[0002] The present subject matter is related to that disclosed in the assignee's other patents and applications, including U.S. Pat. No. 5,862,260, and copending applications Ser. Nos. 09/074,034, 09/127,502, 09/164,859, 09/292,569, 09/292,569, 09/314,648, 09/342,675, and 09/343,104.
BACKGROUND OF THE INVENTION
[0003] Watermarking is a well-developed art, with a great variety of techniques. Generally, all vary an original signal (corresponding, e.g., to audio or image data-video being considered a form of image data) so as to encode auxiliary data without apparent alteration of the original signal. Upon computer analysis, however, the auxiliary data can be discerned and read. (For expository convenience, the following discussion focuses on image data, although the same techniques are generally applicable across all watermarking applications.)
[0004] A problem inherent in all watermarking techniques is the effect of the underlying image signal. In this context the underlying image signal—although the intended signal for human perception—acts as noise for purposes of decoding of the watermark signal. In most cases, the energy of the image signal far exceeds that of the watermark signal, making watermark detection an exercise in digging out a weak signal amidst a much stronger signal. If the encoded image has been degraded, e.g., by scanning/printing, or lossy compression/decompression, the process becomes still more difficult. As watermarks become increasingly prevalent (e.g., for device control, such as anti-duplication features in reproduction systems), the importance of this problem escalates.
[0005] The present invention seeks to redress this problem.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] [0006]FIG. 1 shows how an image may be tiled with a watermark.
[0007] [0007]FIGS. 2 and 3 are flow charts illustrating methods according to different embodiments of the invention.
DETAILED DESCRIPTION
[0008] To mitigate the problem of detecting a watermark signal in the presence of a much-stronger image signal, certain choices are made early in the process—at the embedding operation.
[0009] The “noise” introduced by the image signal doesn't always hurt the detection process. Sometimes innate biases in pixel values, or other image characteristics (e.g., DCT, wavelet, or other transform coefficients), can actually serve to accentuate the watermark signal and thereby simplify detection.
[0010] Starting with a perhaps overly simple case, consider an image prior to watermark encoding. If the un-encoded image is analyzed for the presence of a watermark, none should be found. However, there are cases in which the innate image characteristics sufficiently mimic a watermark signal that a phantom watermark payload may nonetheless be decoded. If the application permits, the user may then encode the image with this watermark payload. This encoding just accentuates the phantom data signal coincidentally present in the image. Even if all of the added watermark energy is somehow thereafter lost, the watermark may still be detectable.
[0011] Most watermark decoding algorithms are designed to guard against detection of phantom watermarks in un-encoded images. For example, the algorithms may look for checksum bits in the watermark payload; if the payload bits don't correspond as expected to the checksum, the decoder may simply report that no watermark is detected. Other algorithms may employ some confidence metric for each of the decoded bits (e.g., signal-to-noise ratio). Unless the confidence metric for all the decoded bits exceeds a threshold value, the decoder may again report that no watermark is detected.
[0012] In applying the principles detailed in this specification, it is generally desirable to disable or circumvent mechanisms that guard against detection of phantom data so as to essentially force the decoder to make its best guess of what the watermark payload is assuming there is a watermark present. In the case just discussed, this would involve circumventing checksum checks, and lowering the detection confidence thresholds until watermark data is discerned from the un-encoded image.
[0013] The approach just-discussed assumes that the image proprietor has total freedom in selection of the watermark payload. This may be the case when the image is being secretly marked with an identifier whose purpose is to identify unauthorized dissemination of the image—in such case, the identifier can be arbitrary. More commonly, however, the watermark payload data cannot be so arbitrarily selected.
[0014] A variant of the foregoing considers the phantom presence of specific watermark payload bits in the un-encoded image. Many watermark encoding techniques essentially encode each payload bit position separately (e.g., each bit corresponds to specific image pixels or regions, or to specific transform coefficients). In such arrangements, the unencoded image may mimic encoding of certain payload bits, and be indeterminate (or counter) as to others. Those bits for which the image has an innate bias may be incorporated into the watermark payload; the other bits can be set as may befit the application. Again, the image is then watermarked in accordance with the thus-determined payload.
[0015] (The notion that an image may have a preference for certain watermark payload data is expressed in various of my earlier patents, e.g., in U.S. Pat. No. 5,862,260, as follows:
[0016] The basic idea is that a given input bump has a pre-existing bias relative to whether one wishes to encode a ‘1’ or a ‘0’ at its location, which to some non-trivial extent is a function of the reading algorithms which will be employed, whose (bias) magnitude is semi-correlated to the “hiding potential” of the y-axis, and, fortunately, can be used advantageously as a variable in determining what magnitude of a tweak value is assigned to the bump in question. The concomitant basic idea is that when a bump is already your friend (i.e. its bias relative to its neighbors already tends towards the desired delta value), then don't change it much. Its natural state already provides the delta energy needed for decoding, without altering the localized image value much, if at all. Conversely, if a bump is initially your enemy (i.e. its bias relative to its neighbors tends away from the delta sought to be imposed by the encoding), then change it an exaggerated amount. This later operation tends to reduce the excursion of this point relative to its neighbors, making the point less visibly conspicuous (a highly localized blurring operation), while providing additional energy detectable when decoding. These two cases are termed “with the grain” and “against the grain” herein.)
[0017] Again, the foregoing example assumes that the user has flexibility in selecting at least certain of the payload bits so as to exploit watermark biases in the image itself. Commonly, however, this will not be the case. In such cases, other approaches can be used.
[0018] One approach is to vary the origin of the encoded watermark data within the image. “Origin” is a concept whose precise definition depends on the particular encoding technique used. In the watermarking techniques disclosed in the commonly-owned patents and applications, the watermarking is performed on a tiled basis (FIG. 1), with a square watermark data block 14 (e.g., 128×128 pixels) being repetitively applied across the image 12 . Heretofore, the upper left hand pixel of the first data block is made coincident with the upper left hand pixel in the image (the latter is the origin). Thereafter, the watermark block is tiled horizontally and vertically across the image, repeating every 128 pixels. At the right and bottom edges, the tiled data block may overlie the edge of the image, with some of the block lost off the edges. This arrangement is shown in FIG. 1.
[0019] The assignment of the origin to the upper left hand comer of the image is a matter of convention and simplicity more than design. The origin can be moved to the next pixel to the right, or the next pixel down, without impairing the watermark's operation. (The decoding technique detailed in the commonly-owned patents and applications determines the location of the origin by reference to a subliminal graticule signal embedded as part of the watermark. A related system is shown in U.S. Pat. No. 5,949,055. By such arrangements, the encoding origin can generally be placed arbitrarily.) Indeed, in the case just cited, there are 16,384 possible origins (128*128) in the image that can be used. (Beyond the first 128×128 pixels, the tiling starts duplicating one of the 16,384 states.)
[0020] When an un-encoded image is decoded using the upper left hand pixel as the origin, a first set of watermark payload biases, as described above, may be revealed. If the origin is moved a single pixel to the right, a second set of watermark payload biases becomes evident. Likewise for each of the 16,384 possible origins.
[0021] For short payloads (e.g., up to 12 bits), it is probable that one or more of the phantom watermarks that may be discerned from the un-encoded image—starting with different origin points—will exactly yield the desired payload. For longer payloads, an origin can likely be selected that will exhibit a phantom bias for many of the payload bits. The task then becomes one of searching for the origin that yields suitable results. (“Suitable” here depends on the application or the preferences of the user. At one extreme it can mean finding the single origin within the 16,384 possible that yields the best possible phantom watermark results. If several origins yield the same, desired, phantom watermark biases, then each can be analyzed to discern the one yielding the best signal-to-noise ratio. In other applications, searching for a suitable origin can mean finding the first of perhaps several origins that yield the desired innate payload bit biases-regardless of whether there may be others that yield the same payload bit biases at better signal-to-noise ratios. In still other applications, a suitable origin can be any point that yields innate payload bit biases better than the normal upper-left-corner-pixel case. Etc.)
[0022] Except in limited circumstances (e.g., encoding a watermark in a single image that may be replicated billions of times, such as a banknote), an exhaustive search to find the single best origin may be so computationally burdensome as to be impractical. There may commonly be shortcuts and clues based on particular image characteristics and the encoding/decoding algorithms that can be employed to speed the search process.
[0023] The “origin” need not be a spatial location. It can be any other reference used in the encoding process. Quantization-based watermark encoding schemes, for example, may tailor the quantization levels in accordance with the particular innate biases of the image to encode desired watermark data.
[0024] In other embodiments, the suitability of an image to accept a particular watermark having a particular origin may best be ascertained by modifying the image slightly, and analyzing the modified image to determine watermark suitability. For example, a trial watermark (complete or incomplete, reduced amplitude or full amplitude) might be inserted into part or all of the image with a trial origin. The analyzing could then include an attempted reading of the watermark to yield a performance metric (e.g., signal-to-noise ratio). Based on the results thus achieved, the suitability of the image to host such watermark data with that particular origin can be assessed, and the process repeated, if desired, with a different origin. After thus characterizing the suitability of the image to accept watermarks with different origins, the image may be watermarked using the origin found to yield the best performance.
[0025] Although the foregoing discussion focused on changing the origin of the watermarking, other parameters can also be varied to effect the “match” between the innate image characteristics and the watermark data. One such parameter is image resolution. Another is image rotation. Yet another is compression.
[0026] Consider a vector graphic image that is “ripped” to yield a set of pixel data. The conversion can yield any desired pixel spacing (resolution), e.g., 600 dpi, 720 dpi, etc. The different resolutions will yield images that may be differently suited to host a particular set of watermark data. By analyzing the image at different resolutions, one may be found that provides innate image attributes that best tend to reinforce the desired watermark signal.
[0027] Similarly, with rotation. It is not essential that the image be encoded with the “top” oriented vertically. By rotating the image 90, 180, 270 degrees (or even to intermediate rotation states) prior to watermark encoding, a state may be found that provides image attributes tending to assist with the watermark encoding.
[0028] In still other applications, image attributes may be changed by corrupting the image through differing degrees of lossy compression/compression. To human observers, the results of different compression processes may be imperceptible, yet in the encoding domains, the resulting changes may make a particular image better- or worse-suited to encoding with a particular watermark. Again, various such modifications can be made to the original image to try and find a counterpart image that coincidentally has attributes that tend to reinforce the desired watermark signal.
[0029] Image modifications other than changing resolution, rotation, and compression can similarly be pursued; these three are exemplary only.
[0030] Reference was sometimes made above to image attributes that “coincidentially” tended to reinforce the desired watermarking signal. In particular cases, such attributes needn't always be left to chance. For example, in the compression-based approach just-discussed, compression algorithms have a great deal of flexibility in determining what image components to maintain, and which to omit as visually superfluous. The decision whether or not to omit certain image components can be made dependent, in part, on a priori knowledge of a watermark payload that is to be encoded (or retained) in the image, so as to optimize the innate biases in the decompressed image accordingly. Indeed, the entire watermark encoding process may be realized through a suitable compression algorithm that operates to retain or discard image information based at least in part on the watermark-related attributes of the resulting image after processing.
[0031] In still other embodiments, a multi-way optimization process may be performed. The original image can be analyzed to find which of several different origins yields the best results. The original image can then be modified (e.g., resolution, rotation, compression), and a variety of different origins again tried. Still further modifications can then be made, and the process repeated—all with a view to optimizing the image's innate suitability to convey a particular watermark.
[0032] As is familiar to those skilled in the arts, the foregoing methods may be performed using dedicated hardware, through use of a processor programmed in accordance with firmware or software, etc. In the latter case the processor may include a CPU and associated memory, together with appropriate input and output devices/facilities. The software can be resident on a physical storage medium such as a disk, and can be loaded into the processor's memory for execution. The software includes instructions causing the CPU to perform the analysis, search, evaluation, modification, and other processes detailed above.
[0033] The variety of watermarking techniques is vast; the technology detailed above is believed applicable to all. The variety of watermarking techniques is illustrated, e.g., by earlier cited patents/applications, and U.S. Pat. Nos. 5,930,469, 5,825,892, 5,875,249, 5,933,798, 5,916,414, 5,905,800, 5,905,819, and 5,915,027.
[0034] Having described and illustrated the principles of my invention with reference to various embodiments thereof, it will be recognized that the invention can be modified in arrangement and detail without departing from such principles. For example, while the detailed embodiment particularly considered image data, the same principles are applicable to audio data. (The “origin” -based approaches would commonly use a temporal origin.) Similarly, the detailed techniques are not limited solely to use with digital watermarks in a narrow sense, but encompass other methods for processing an image to encode other information (e.g., for authentication or digital signature purposes, for image-within-an-image encoding, etc.—all regarded as within the scope of the term “watermark” as used herein.) Accordingly, I claim as my invention all such embodiments as may come within the scope and spirit of the following claims and equivalents thereto.
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Watermark detection in an image or the like is optimized by exploiting the innate biases in the image to emphasize the watermark signal. The watermark signal can be trial-located with different origins in the image to find one that yields improved results. Similarly, the image can be processed (e.g., by changing resolution, rotation, or compression) so as to change the innate biases to better reinforce the watermark signal. Compression of an image can be done in accordance with a desired watermark signal, with the compressor deciding which image components to retain and which to discard based, in part, on a watermark signal that is to be encoded (or maintained) in the image.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 61/178,216, filed May 14, 2009, the content of which is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a barrier wall system, more specifically, a non-load bearing wall panel that when joined together with other panels is used as a barrier.
BACKGROUND OF THE INVENTION
A temporary, non-load bearing wall panel that when joined together with other like panels, is used as a barrier (also known as a barricade wall) that keeps a construction area, vacant store, or any other undesirable element out of the reach and view of pedestrians.
Partition systems are often employed to separate portions of a building or room. Partitions serve as a barrier to unsightly construction, noise, light and the like. In construction zones, partitions are also useful for protecting a clean area from a work area.
Workers at construction sites often use rudimentary techniques for installing partitions. Some simply nail, screw, or staple the curtain or partition material to the floor, ceiling, and abutting walls, resulting in damage to their surfaces. Others tape or otherwise adhere a curtain or plastic sheet to the walls and ceilings. The tape usually fails to stick, but if it does stick, as the tape is removed, paint usually pulls off with the tape or adhesive is left behind.
There is a need for an easy to install barrier in-situ that provides flexibility to be adapted to various space requirements and customer's purposes. There is a need for a dust-free panel system that effectively provides dust protection across the panel system. There is a need for panels that could be laminated with a visual graphic for reasons of aesthetic enhancement, advertisement of service, announcement of future business expectations, with seamless connections without frames and interruptions in the visual image surface. There is a need for a door and/or window display, dust curtains, etc. that may be added to the panels as dictated by the end user. There is a need to have environmentally friendly barriers that can be reused continually over and then be able to be totally recycled at the end of expected life term thereby greatly reducing landfill waste.
SUMMARY OF THE INVENTION
A temporary, non-load bearing wall panel that when joined together with other like panels, is used as a barrier (also known as a barricade wall) that keeps a construction area, vacant store, or any other undesirable element out of the reach and view of pedestrians. If required by the end user, the panels could be laminated with a visual graphic for reasons of aesthetic enhancement, advertisement of service, announcement of future business expectations, etc. A door and/or window display, dust curtains, etc. may be added to the panels as dictated by the end user.
One aspect is a non-loading bearing panel and connection system including at least two panels, an aluminum frame, a connector, and a quick connect clasp assembly. Each of the at least two panels includes two vertical sides, two horizontal sides, and a planar panel extending therebetween. The planar panel has a front surface and a back surface. The aluminum frame is attached to the back surface of the at least two panels, and the aluminum frame extends adjacent the perimeter of the two vertical sides defining vertical frames. The connector is attached to the aluminum frame along one of the two vertical sides. The quick connect clasp assembly removably joins together two adjacent vertical frames from the opposing at least two panels. The at least two panels are connected together defining a panel joint, and the connector extends between the panel joint preventing dust from flowing through the panel joint.
Additional aspects include each of the at least two panels provides a frameless front surface, the panels are formed from recyclable raw materials, i.e. a co-polymer sheet, the panels are flame retardant, and/or at least one of the at least two panels can be flexible and the two vertical sides bend at an angle up to about 270° defining a corner panel. Further, at least one of the at least two panels can further include the aluminum frame attached to the back surface of the at least two panels, and the aluminum frame extends adjacent the perimeter of the two horizontal sides defining horizontal frames. At least one of the at least two panels can further include the aluminum frame attached to the back surface of the at least two panels extending between the vertical frames or the horizontal frames providing support along the length of the panels.
As above-mentioned, a vinyl graphic can be applied to the front surface of each panel, wherein the graphic is seamless between the panel joints. The system can further include a door attached to one of the at least two panels, and the door is flush mounted to the front surface of at least one of the at least two panels.
Additionally, the system can further include a wall shop attached to the vertical frames of adjacent panels. The wall shop is an inset box-like structure including a bottom wall, a top wall, a back wall, two opposed sidewalls and a front planar panel. The back wall and the two opposed sidewalls extend between the top wall and the bottom wall. The front planar panel defines an open front to access an interior to the wall shop and the front planar panel is flush with the front surface of the at least two panels. The front planar panel is attached to the vertical frames of the at least two panels.
Furthermore, the connector can be directly attached to one of the two vertical sides and the aluminum frame is slidably attached to the connector. The connector includes a male coupling member and a female coupling member, and the female coupling member and the male coupling member of opposing panels are mateable therewith to prevent dust from flowing through the panel joint and to assist with alignment of the panels. The connector can include a tail, a head and a middle attachment section extending between the tail and the head. The aluminum frame is slidably attached to the head, and the tail includes a longer portion defining the male coupling member and a shorter portion. The longer portion protrudes from the perimeter of one of the two vertical sides, and another of the two vertical sides is arranged having the shorter portion inset from another of said two vertical sides and inset from the aluminum frame defining the female coupling member. Additionally, the tail can be attached to the back surface of the panel. Further, the connector can be directly attached to the back surface of the panel, the connector includes a head and a middle portion attached to the head, and the aluminum frame slidably attaches to the head of the connector.
Additionally, the quick connect clasp assembly is a U-shaped plate having a planar plate and two end plates perpendicular to the plate. The end plates are connected to the planar plate by materials continuity, an L-shaped plate extends from the planar plate perpendicularly therefrom, and the L-shaped plate extends a portion of an edge of the planar plate. The locking portion is attached to the planar plate, and the locking portion includes a joining member attached to the planar plate, a back portion pivotally connected to the joining member, an elongated curved portion pivotally connected to the back portion. The elongated curved portion extends beyond the planar plate to attach to one of the aluminum frames, pivoting the back portion away from the elongated curved portion locks the quick connect clasp assembly to the aluminum frame.
Further aspects are each of the end plates includes a pair of openings therethrough for attachment of the panel to a perpendicular surface; the planar plate includes a pair of elongated openings perpendicular to the locking portion; a fastener extends through the opening and a locking member secures the fastener to the planar plates; and the quick connect clasp assembly is removably attached to the aluminum frames and slidable along the aluminum frame.
BRIEF DESCRIPTION OF THE DRAWINGS
For a further understanding of the above objects and advantages, reference is made to the following detailed description and to the drawings, in which:
FIG. 1 is a back plan view showing a partial panel assembly including horizontal supports of the present invention.
FIG. 2 is a cross sectional view of the support frame of the present invention.
FIG. 3 is a perspective view of the support frame of FIG. 2 .
FIG. 4 is a cross sectional view of the connector member of the present invention.
FIG. 5 is a perspective view of the connector member of FIG. 4 .
FIGS. 6 and 7 are cross sectional views of a partial panel assembly of the present invention.
FIG. 8 is a cross sectional view of the panel assembly of the present invention.
FIG. 9 is a cross sectional view of the panel assembly of the present invention.
FIG. 10 is a cross sectional view of the connector member of the present invention.
FIG. 11 is a back plan view showing a partial panel assembly including a vertical support of the present invention.
FIG. 12 is a back plan view showing a corner panel assembly absent horizontal supports of the present invention.
FIG. 13 is a back plan view of various panel assemblies attached together.
FIG. 14 is a cross sectional view of the quick-connect of the present invention.
FIGS. 15 and 16 are perspective views of the quick-connect of FIG. 14 .
FIGS. 17 and 18 are top plan views of the quick-connect of FIG. 14 .
FIGS. 19-24 are views of the insertable wall shop of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention is shown in FIGS. 1-24 and described herein. Unlike other types of barricades that are made of non-recyclable material such as, sheet rock (gypsum board), wood, thermally laminated pressed board, etc., this unique wall panel is constructed of a highly fire retardant, recycled co-polymer sheet that is attached to a rigid recycled aluminum frame by the use of cement/adhesive, all 100% recyclable. Since the co-polymer sheet could be separated from the aluminum frame, the entire wall panel could be easily recycled if the panel is ever damaged beyond reasonable repair. Additionally, the wall panel provides for easy maintenance because it never has to be painted and requires only soap and water to clean. Further, 90.9% of a typical 4′×12′ frame is welded for high strength.
FIG. 1 shows the panel assembly 10 of the present invention. FIG. 1 shows the panel assembly 10 is generally rectangular in-shape but other configurations are contemplated. Panel assembly 10 includes a frame structure 28 and a panel 20 attached thereto. A frame structure 28 is defined by a pair of vertically extending side frames 12 , 14 , and a pair of horizontally extending side frames 16 , 18 and horizontal cross members 22 extending between the side frames 12 , 14 . The frame structure 28 is formed from aluminum to provide strength and light weight. The horizontally extending side frames include a top frame 16 and a bottom frame 18 . The horizontal cross members 22 extend between the vertically extending side frames 12 , 14 and top frame 16 and bottom frame 18 to provide structural support to the panel 20 .
The bottom frame 18 extends along the bottom of the panel assembly 10 such that the width (W) of the panel assembly 10 is the same as the length of the bottom frame 18 . Side frames 12 , 14 rest on top of and attach to the bottom frame 18 such that the external surface of side frames 12 , 14 do not exceed the perimeter of the bottom frame 18 , as shown in FIG. 1 . The side frame 12 extends from the bottom frame 18 to the top frame 16 . The internal side surface of the side frame 12 abuts the end of the top frame 16 , lapping the joint, and is attached to the top frame 16 such that the top frame 16 does not add to the length (L) of the panel assembly 10 . The side frame 14 abuts the bottom surface of the top frame 16 and the top surface of the bottom frame 18 , as shown in FIG. 1 . FIG. 1 also shows side frame 12 is longer than side frame 14 by the thickness of top frame 16 . Bottom frame 18 is longer than the top frame 16 by the width of side frame 14 .
The cross members 22 are connected to the vertically extending side frames 12 , 14 by welding forged aluminum gussets to the corner where the cross member 22 extends perpendicularly from the vertically extending side frames 12 , 14 . Additionally, gussets 24 are used in the four corners that connect each vertically extending side frame 12 , 14 to each of the horizontally extending frame 16 , 18 . Panel 20 is a planar sheet attached to the frame structure 28 . FIGS. 1 and 8 show panel 20 includes two vertical sides ( 20 a , 20 b ), two horizontal sides ( 20 c , 20 d ), a front surface 20 e and a back surface 20 f . Panel 20 is constructed of a highly fire retardant, recycled co-polymer sheet. The recycled co-polymer is specially formulated with fire and smoke inhibitors that allow the extruded panel to meet ASTM E84, Class 1, standards that are the highest classification for Surface Burning Characteristics of Building Materials. Panel 20 has a smooth surface on one side and a hair-cell textured finished on the other side. The smooth surface finish insures proper surface binding with the first connector 26 or with the frame 28 and the hair-cell textured surface resists soiling and provides easy removal of vinyl graphic applications. Sandwiched between the panel 20 and the vertically extending frame 12 is a first connector member 26 which protrudes from the profile of the frame structure 28 . The first connector member 26 is attached to the edge of the panel 20 by an adhesive material to mechanically bond the first connector member 26 to the panel 20 such as glue, cement, tape and the like. The adhesive material 25 shown in FIGS. 8 and 9 is a special industrial strength, high tack, and double-sided foam core tape. The first connector member 26 provides the appearance of no seams, seamlessly securing two panel assemblies 10 together. A first connector member 26 may also be applied to the top frame 16 of the panel assembly 10 to allow for stacking of panel assemblies 10 in the vertical direction, as shown in FIG. 1 . The panel assembly 10 can be stacked at greater heights than other systems due to the panel assembly 10 design and the inherent strength of the materials, as shown in FIG. 13 . When the wall panel assembly 10 are joined side by side or extended at the top, the joints of the panel 20 are barely visible creating an almost seamless wall. The panels 20 are almost seamless when joined together as shown in FIGS. 8 and 9 , so there are no noticeable surface imperfections when a vinyl graphic is applied to the front surface 20 e of panel 20 , FIG. 8 .
FIGS. 2 and 3 show a cross sectional view of the individual frame components 44 which forms the frame structure 28 , as in FIG. 1 . The individual frame components 44 are formed from an extruded aluminum and have an X-shaped profile. The individual frame components 44 include a center core 46 which is square in-shape and arrow portions 48 extending from each corner of the center core 46 . The arrow portion 48 includes a base 50 extending from the center core 46 to an arrow head portion 52 . The surfaces of the center core 46 , base 50 and internal surface of the arrow head portion 52 creates a frame channel 54 for receiving the first connector member 26 , as in FIGS. 6 and 7 .
A first connector member 26 or a second connector member 56 , as shown in FIGS. 4 and 10 respectively, is used in conjunction with the frame structure 28 and a quick-connect member 70 of FIG. 18 to attach two panel assemblies 10 together. There are two types of connector members. FIGS. 4 and 5 show the first connector member 26 which includes a tail 32 . FIGS. 9-10 show a second connector member 56 absent a tail. The first connector member 26 is an elongated connector co-polymer profile made from 100% recycled material that slides into the aluminum frame slot, or channel 30 and protrudes beyond the frame 28 of which is to attached to, as shown in FIGS. 6-8 . FIGS. 4 and 5 show the first connector member 26 is an extruded plastic member including a tail 32 , a head 34 and a middle attachment section 36 attaching the head 34 to the tail 32 . The head 34 includes a flat top portion 34 a with angled sides 34 b extending therefrom. The angled sides 34 b extend between the top portion 34 a and a vertical side 34 c . The vertical side 34 c extends between the angled sides 34 b and an inwardly horizontal lip section 34 d . The horizontal lip section 34 d is perpendicularly attached to the middle attachment member 36 . The tail 32 is a generally planar and is slightly offset from the attachment point 32 b to the middle attachment member 36 , such that the tail 32 extends on either side from the middle attachment 36 but the tail 32 extends longer on one side than the other side. The tail 32 includes a longer portion 32 a , attachment point 32 b and a shorter portion 32 c . The horizontal lip 34 d , middle attachment 36 and the tail 32 define channels 38 , 39 for accepting the frame member therein.
FIGS. 6 and 7 show the cross sectional view of the vertically extending side frame 12 , 14 attached to the first connector member 26 . A first connector member 26 is sandwiched between each vertically extending side frame 12 , 14 and the panel 20 . The head 34 of the first connector member 26 seats within the frame channel 54 of the frame to attach the vertically extending side frame 12 , 14 to the first connector member 26 and the panel 20 . FIG. 6 shows the first connector member 26 attached to the side frame 12 and the panel 20 . The first connector member 26 is engaged with the side frame 12 such that the longer tail 32 a extends beyond the perimeter of the panel 20 . FIG. 7 shows the first connector member 26 is attached to the side frame 14 such that the shorter tail 32 c extends towards the edge of the panel 20 but does not exceed the perimeter of the panel 20 . FIG. 7 shows a side channel 30 is defined by the space between the panel 20 , shorter tail 32 c and the frame 14 . The side channel 30 accommodates the protruding profile of the longer tail 32 a from an adjacent adjoining panel assembly 10 which is connected to the panel assembly, as shown in FIG. 8 . The side channel 30 provides a connection guide and the longer tail 32 a provides a dust shield when two or more panels are connected side by side, or top to bottom.
FIG. 8 shows the first connector member 26 directly connected to the panel 20 . FIG. 9 shows the second connector member 56 is slidably attached directly to two individual aluminum frames 28 from different assembly panels 10 . FIG. 10 shows the cross sectional view of the second connector member 56 which is similar to first connector member 26 of FIGS. 4 and 5 but without the tail 32 . The second connector member 56 includes a head 58 attached to a shaft, or middle portion 60 . The head 58 is similar to the head 34 of first connector member 26 , and the middle portion 60 is similar to the middle attachment section 36 of first connector member 26 . Specifically, the head 58 includes a flat top portion 58 a with angled sides 58 b extending therefrom. The angled sides 58 b extend between the top portion 58 a and a vertical side 58 c . The vertical side 58 c extends between the angled sides 58 b and an inwardly horizontal lip section 58 d . The horizontal lip section 58 d is perpendicularly attached to the middle portion 60 . The middle portion 60 extends perpendicularly from the horizontal lip section 58 d . The first connector member 26 and the second connector member 56 provide a dust barrier between the connected panel assemblies 10 .
FIG. 11 shows a panel assembly 11 which is similar to panel assembly 10 of FIG. 1 including a frame structure 17 and a planar panel 20 . The frame structure 17 includes top frame 16 , bottom frame 18 and side frame 12 and 14 . Panel assembly 11 includes vertical cross member 23 which extend between the top frame 16 and the bottom frame 18 . The vertical cross member 23 is attached to the top and bottom frames 16 , 18 by welding a gusset 24 to the perpendicular connection corners between the vertical cross member 23 and the top and bottom sides 16 , 18 . While FIG. 11 shows one vertical cross member 23 , it is contemplated that a plurality of vertical cross members may be included. The frames 16 , 18 and vertical cross member 23 are made from the same frame component 44 as shown in FIGS. 2 and 3 .
FIG. 12 shows a corner panel assembly 13 which is similar to the panel assembly 10 of FIG. 1 including a pair of vertically extending sides 15 and a planar panel 20 . Panel assembly 13 is absent horizontal frames and cross members to allow the panel 20 to flex and bend providing curved corners, as shown in FIG. 13 . The corner panel assembly 13 exhibit flexural capabilities, such that the panel will be able to bend at an angle (A) up to 270 degrees as shown in FIG. 13 .
FIGS. 13-15 and 18 show two or more wall panel assemblies 10 and corner panel assembly 13 are removably secured together by use of a specialized quick-connect spring loaded clasp and plate assembly or quick-connect 70 . The quick-connect 70 straddles two adjoining wall panel frames 28 on the back side of the panel assemblies 10 where the two wall panel assemblies come together. Once in place, one or two bolts 62 are placed through slots 72 in the quick-connect plate 70 and into the framing as shown in FIG. 14 . Once tightened, the bolts 62 ensure a positive, secure connection. The quick-connect 70 also doubles as an attachment point for either top or bottom (or both) anchoring the panel assembly 10 to the floor or other structure. FIG. 13 also shows a door 27 flush mounted to one of the panel assemblies 10 .
FIGS. 14-17 show the quick-connect 70 of the present invention. The quick-connect 70 includes a plate 74 and a clamp mechanism 90 . The plate 74 is rectangular in-shape with two ends 76 on either side of a center portion 78 . Each of the two ends 76 is bent upwardly, perpendicular to a center portion 78 . The plate 74 has a U-shaped side profile with one side edge 64 being an unattached end and the other side edge 66 having an L-shaped extension member 80 extending from a portion of the other side edge 66 . The L-shaped extension member 80 extends downwardly from the center portion 78 in the opposing direction of the two ends 76 . The L-shaped extension 80 includes a longer leg 82 and a shorter leg 84 . The longer leg 82 is perpendicularly extending from the center portion 78 . The shorter leg 84 extends from the other end of the longer leg 82 , and parallel to the center portion 78 . FIG. 14 shows the L-shaped extension member 80 in combination with the center portion 78 provide securement of the quick-connect 70 about one of the frame structures 28 , i.e. vertical side 14 . The plate 74 includes a plurality of elongated slots 72 and holes 68 . The elongated slots 72 are used in combination with t-bolts 62 to secure the quick-connect 70 to the frame structure 28 . Bolts, screws or other anchoring hardware are placed through holes 68 to attach the panel assembly 10 to a floor or other external structure. The bottom surface of plate 74 is in contact with the support structure. The top surface of plate 74 includes a clamp mechanism 90 attached thereto.
The clamp mechanism 90 includes a base plate 92 , a hook 94 and a lever 96 as shown in FIGS. 15-18 . The base plate 92 is a flat, planar plate having a U-shaped design. The base plate 92 is attached to the plate 74 by mechanical attachment such as welding. The base plate 92 has a pair of extensions 93 which extend perpendicularly from the base plate 92 . Each extension 93 includes an aperture 91 for acceptance of a rod 86 therethrough. The lever 96 is seated between the pair of extensions 93 . The lever 96 is attached to the base plate 92 by the rod 86 which extends through the apertures 91 of the extensions 93 and though holes (not shown) in the lever 96 . The lever 96 pivots on the rod 86 . The lever 96 includes a pair of sidewalls 97 attached on opposing edges of a bottom wall 98 , and an angled front wall 99 extending from an edge of the bottom wall 98 . The front wall 99 is used by the operator to pivot the lever 96 into and out of a locking position. Hook 94 is pivotally attached to the lever 96 . Bar 88 extends through apertures in the lever 96 and one end of hook 94 is wrapped about the bar 88 such that the hook 94 pivotally rotates about the bar 88 . Hook 94 is a curved strip 95 of metal with an L-shaped attachment 100 at one end for securement to a frame structure 28 , i.e. vertical side 12 as shown in FIG. 14 .
FIGS. 15 and 18 show the clamp mechanism 90 in the locked position where the lever 96 and the hook 94 extend in opposite directions and the hook 94 is in contact and secured against the frame structure 28 . FIG. 17 shows clamp mechanism 90 in an unlocked position where the hook 94 is extended outward in the same direction as the lever 96 , the lever 96 is pivoted over such that the top surface is facing upwardly, and the bottom surface is against the hook 94 . Also the hook 94 is disengaged from the frame structure 28 . Pivoting the lever 96 extends the hook outwardly away from the base frame 92 or inwardly toward the base frame 92 for engagement and locking to the frame structure 28 .
FIG. 18 shows the clamp mechanism 90 in the locked position and securing two frame structures 28 together. FIG. 15 shows the clamp mechanism 90 in the locked position and securing two frame structures 28 together in addition to securing the frame structures 28 to an external support structure.
The frame structure 28 and clamp mechanism 90 is used to form panels as a temporary wall as above discussed. In addition, the frame structure 28 and clamp mechanism 90 can be used to incorporate various features into the panel assembly 10 , such as doors, windows, built in wall units and the like. For example, access doors may be added into a panel and are flush mounted, as shown in FIG. 13 . The framing of the various features are attached to the frame structure 28 and the frame structure 28 is attached to the panel assembly 10 in the same manner as above described, using the clamp mechanism to secure the frame structures together.
FIGS. 19-24 show an insertable wall shop 110 using frame structure 28 . The wall shop 110 has a generally rectangular box shape free standing unit with a bottom wall 112 , a top wall 113 , a back wall 114 and two opposed sidewalls 115 , 116 extending therebetween and an open front 117 . The open front 117 is defined by the top wall 113 , bottom wall 112 and two opposing sidewalls 115 , 116 . Surrounding the open front 117 is a front planar panel 118 . FIG. 20 shows the frame structure 28 attached to the bottom wall 112 , the top wall 113 , the back side wall 114 and the opposed sidewalls 115 , 116 to provide structural support for the walls. The frame structure 28 of the wall shop 110 includes vertical extents and horizontal extents to provide further support across the walls. The frame structure 28 is also attached to the front planar frame 118 about the open front 117 to create an almost seamless juncture when attached to the panel assembly 10 . The wall shop 110 is attached to the frames structure 28 of the panel assembly 10 on either side of the wall shop 110 to provide an insertable wall shop 110 where the front planar panel 118 is flush with the panel assembly 10 as shown in FIGS. 23 and 24 . The frame structure 28 of the wall shop 110 is attached to the panel assembly 10 in the same manner as opposing panel assemblies 10 are attached together using a second connector member 56 of FIGS. 9 and 10 in conjunction with a quick-connect member 70 of FIGS. 15-17 , as above-discussed.
The wall shop 110 may include various components attached and inserted within such as a cabinet 119 and a drawer 120 . Additionally, the back wall 114 includes a slat wall panel 121 with horizontal Z-channels 122 formed to allow for attachment of racks, hooks, shelving and cabinet 119 using a hook 123 , as shown in FIGS. 19 and 20 . The wall shop 110 also includes lighting 125 , a receptacle 126 which is powered through the back wall 114 , and/or an overhead coiling door 124 which is concealed by the front planar panel 118 as shown in FIGS. 19 , 20 , 23 and 24 . The coiling door 124 is used to enclose the wall shop 110 and cover the front open wall 117 . The coiling door 124 uncoils and recoils along a track as shown in FIGS. 19 , 23 and 24 . L-shaped lockable clasps 125 are located in the door and the base of the wall shop 110 as shown in FIGS. 20 , 23 and 24 . The L-shaped lockable clasps 125 are used to secure the coiled door 124 to the front planar panel 118 at the base of the wall shop 110 in a closed position.
While various embodiments of the present invention are specifically illustrated and/or described herein, it will be appreciated that modifications and variations of the present invention may be effected by those skilled in the art without departing from the spirit and intended scope of the invention. Further, any of the embodiments or aspects of the invention as described in the claims or in the specification may be used with one and another without limitation.
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A temporary, non-load bearing wall panel that when joined together with other like panels, is used as a barrier (also known as a barricade wall) that keeps a construction area, vacant store, or any other undesirable element out of the reach and view of pedestrians. If required by the end user, the panels could be laminated with a visual graphic for reasons of aesthetic enhancement, advertisement of service, announcement of future business expectations, etc. A door and/or window display, dust curtains, etc. may be added to the panels as dictated by the end user.
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FIELD AND BACKGROUND OF THE INVENTION
This invention provides a lightning protection device for structures, civil and industrial buildings, plants or the like. It includes an atmospheric electrode which is insulated from the ground and means suitable for earthing or grounding the electrode when the potential difference, which is associated with the electric field at ground, exceeds a pre-determined value.
The inventive device develops a preventive action by interacting during the downward phase of the discharge. Therefore, it can stop the advancing and development of the discharge and avoid the formation of return strokes, which is the most dangerous effect of lightning.
First of all, it is opportune to summarize the phenomena which lead to the formation of lightning. These phenomena are not yet fully explained. During storms we have inside the clouds, the formation of a storm nucleus characterized by a greater concentration of electric charges, generally positive in the upper layers and negative in the lower zones, at a distance from ground of about 2-4 km.
Therefore, between the earth's surface and clouds a strong electric field is produced. The potential difference can reach 100,000,000 volts.
When the potential difference succeeds in overcoming the dielectric resistence of air, lighting is produced, generally beginning with a leader stroke which moves in zig-zagging fashion toward the earth and carries a high quantity of current.
During the final downward phase the electric field at ground reaches such high values that a certain quantity of opposite sign charges (streamer) leaves the ground to meet the downward stroke. A conductive channel is thus produced through which the leader stroke charges are scattered to ground. A violent return stroke then occurs with development of heat and luminous energy. This is the most dangerous effect of lightning.
The described phenomena are widely illustrated in several scientific publications. See in particular:
M. A. Uman "Lightning" Mc Graw-Hill (1969).
R. H. Golde (Edited) "Lightning: Physics of Lightning and Lightning Protection" Academic Press (1977).
J. A. Chalmers "Atmospheric Electricy" Pergamon Press, Oxford (1967).
H. Baatz "Uberspannungen in Energieversorgungsnetzen" Springer-Verlag (1956).
T. Suzuki, F. Miyake, I. Kishizima "Study on experimental simulation of lightning strokes" IEEE-PAS April 1981.
The presently employed devices for lightning protection include one or more catching elements which are connected to earth by means of an opportunely sized conductor so as to constitute a preferential way for the strokes to be scattered at ground. These catching elements generally consist of pointed metallic rods or catching nets which are fixed to the upper part of the structures to be protected and connected to buried earth elements.
Such lightning rods present however several disadvantages: In the first place they offer a limited protection because they are not capable of bearing strokes of greater intensity than that for which they have been fitted.
Moreover, they are expensive because of their particular connection to earth, and require periodical maintenance.
More recently, some experiments were made with lightning rods provided with radioactive points in order to make the lightning rods more efficient. The hoped for results, however have not been obtained in this case either. Moreover, radio-active points can represent a danger to the extent that they have been forbidden in some countries.
The Italian Patent No. 767,809 in the name of De Bernardi describes means to protect TV antennas from lightning. To this end circular shielding elements are provided near the antenna dipole, to form a barrier in the vicinity to the parts most exposed to the danger of strokes.
According to the teachings of such patent, the circular shielding elements deviate the lightning strokes and oppose their effects. In other publications by the same author reference is made to protection devices the aim of which is to disperse the stroke over a wide surface so as minimize the destroying effects thereof, or to the exploitation of the high frequency electromagnetic fields to produce a shielding barrier which can deviate the lightning. However, no relevant teachings are given, nor arguments are brought in support of these theories and the working of the relative devices is not described either.
SUMMARY OF THE INVENTION
In any case the devices known at present have the aim of driving the lightning into a preferential path, or to disperse it over a wide surface. On the contrary, the device according to the present invention prevents the evolution of the lightning flash by acting on the leader stroke while the leader stroke is approaching the ground.
To this end, the device according to the invention works to favour the detaching from the ground, during one or more stages, of electric charges, which converge toward the leader stroke front, thus annulling the same.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is now described in detail, by way of a non limiting example, with particular reference to the enclosed figures, wherein:
FIG. 1 schematically shows a device according to the invention;
FIG. 2 shows the equivalent circuit for the device according to the invention;
FIG. 3 schematically shows the interaction between the leader stroke and the device and;
FIGS. from 4 to 8 schematically show the different operative phases of the device in respect to a leader stroke.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The device according to the invention consists substantially of a metallic atmospheric electrode 1 which is connected to the upper pole of a varistor arrester 2, whose opposite pole is connected to an earth electrode 3 by means of a conductor 4. Electrode 1 has a dome-shaped or spherical top area.
The electrode-varistor unit is mounted on a support 5 which is provided with an insulated base 6, fixed at the upper part to the structure 7 to be protected.
Near the lower part of the varistor 2 an electrostatic shield 8, which consists, for instance, of a metallic ring or the like, is present.
The electrode 1, which will preferably have a wide radius roundish shape, could be made for instance of aluminium.
The varistor 2 will preferably be of the zinc-oxide type. Such varistors are now used for different applications, in particular to protect electric lines from overvoltages.
The dimensions of the conductor 4 are considerably smaller than those of the condustors employed for traditional lightning rods. In fact, as they have to conduct low currents (as will be explained herein after) it is sufficient that its section be of about 1/5-1/8 that of the usual earth conductors.
FIG. 2 shows the equivalent circuit of the device according to the invention, where: ρ 0 is the resistivity of the layers produced by the poisoning elements (≃10 10 ≠Ω·cm.), being a non-linear function of the electric filed intensity;
P z .sbsb.n 0 is the zinc resistivity (≃1Ω·cm.);
Cs--is the equivlaent capacitance of the varistor (10-100 μF);
Rct--is the equivalent resistance of the earthing conductor;
Lct--is the equivalent inductance of the earthing conductor; and
Zt--is the equivalent earth impedance.
For a better understanding of the invention, there will now be provided a detailed explanation of the working thereof during its different phases and of the phisical principles on which it is based.
Further we will call:
Ke--the electric field intensity near the electrode;
Ks--the electric field intensity between the varistor poles;
Kc--the electric field value corresponding to the conduction state of the varistor; and
Kcs--the critical value of the electric field for the formation of upward strokes.
The gathering of electric charges Q n (FIG. 3) in the lower part of the cloud induces, between the cloud and the earth, an electric field where the device is present.
FIG. 3 shows the outline of the lines of force of said electric field. A concentration of elelctric charges develops on the electrode 1, which is a function of the electrode radius and of the electric field at ground.
When the potential difference between the cloud and the ground reaches a value capable of overcoming the dielectric resistance of the air, the formation of a downward leader stroke (in particular toward the electrode 1) occurs.
The overall electric charge of the leader stroke is about 5 C (according to indirect measurement), distributed with a density of about 0.5 mc/ml.
As the downward stroke gets nearer, it causes the separation of the charges present in the electrode; These charges concentrate in the upper or lower part of the electrode according to the sign. The varistor 2 is fit to operate and to become conductive when the electric field value is slightly lower than the critical value (3 to 5 KV/cm) at which the formation of upward streamers from the earth structures occurs. Therefore, when Ks<Kc the atompspehric electrode can be considered as electrically insulated from the earth.
The electrode acts as a metallic body, insulated and with null total charge, immersed in an electric field. Consequently, electric charges of opposite sign concentrate in the upper and lower part of the electrode, by electrostatic induction (FIG. 4).
When Ks exceeds the critical value Kc (because a leader stroke gets near the protected structure), the varistor becomes a conductor and the electrode becomes totally positive with further intensification of Ke (FIG. 5). During this phase a current flows through the arrester, allowing a net transfer of charges from the ground to the atmospheric electrode.
Note that the current passing through the earth conductor is lower than the first return stroke of the lightning. This is due to the lower associated charge.
The electric charge on the atmospheric electrode acts as a shield for the underlying part of the apparatus and annuls the electric field inside the arrester.
Therefore, the varistor passes to the interdiction state again (FIG. 6). The electric field Ke increases further and comes near the Kcs value, because of the leader stroke getting always nearer to it.
In the vicinity to the atomospheric electrode the electric field conditions become such as to produce a process of `corona` discharges. The discharges move toward the downward leader stroke of opposite sign (Ke≧Kcs).
Therefore, a correspondent quantity of charge is annulled in the leader stroke without the upward flux of charge affecting the whole of the apparatuses underlying the atmospheric electrode. During this last phase the Ks value increases again.
After each working the apparatus is restored to the initial conditions and is ready for another working; this is important when the quantity of charge transferred to the downward leader stroke is not enough to annul it completely and to stop its advancing toward the protected structure.
However, the apparatus can never represent a preferential path for the leader stroke--because the atmospheric electrode--earth connection is off.
The use of an atmospheric electrode with a wide radius of curvature allows a considerable charge storage before `corona effluvium` phenomena or micro-discharges occur. The electric field increase near the electrode is caused by the variation in the induced charge density. As the high-value field area is wide, charges leaving the electrode can cover a great distance before being confined in areas where the field intensity corresponds to a stasis condition.
It should be noted that, thanks to the conduction characteristics of the varistor the polarity of the lower part of the stormy cloud--that is the leader stroke polarity--does not affect the protective efficiency of the device, but only the ways of production and spreading of the corona effluvium phenomena.
An expert in the art can provide for several changes and variations which should all fall--however--within the ambit of the present invention.
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An atmospheric electrode is charged by electrostatic induction from a leader stroke which is associated with lightning formation. The electrode is earthed through a varistor which becomes conductive when the value of the tension associated to the electric field at ground exceeds a pre-determined value. In this way, a destructive return stroke, which usually follows a leader stroke during lightning formation, is avoided.
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BACKGROUND OF THE INVENTION
The invention is in the field of tools and methods for use in connection with maintained environments found in vapor phase deposition (VPD) processes, such as but not limited to vacuum environments maintained in molecular beam epitaxy (MBE) machines. In particular, the invention is directed to tools and methods for reloading source materials and performing maintenance in VPD environments, such as maintained in an MBE machine, without the necessity of breaking the vacuum of the environment to perform the reload or maintenance operation.
MBE is a technology that was developed in the early 1970's for the purpose of growing high-purity crystals, particularly epitaxial layers of compound semiconductors. Numerous types of crystal materials may be grown in MBE machines, but the most widely-used application today is III-V compound semiconductors (so called because the two elements used in forming the semiconductor are found in Groups IIIB and VB, respectively, of the periodic table of elements). Gallium Arsenide (GaAs) and other III-V compound semiconductor materials are widely used in optoelectronic components found in cellular telephones, lasers, microwave equipment, and other electro-optical applications.
In the MBE process, the elements that the semiconductors are made from are deposited onto a heated crystalline substrate wafer in the form of “molecular beams” to form thin epitaxial layers. The molecular beams are formed from thermally evaporated elemental sources. To obtain the necessarily high purity in the epitaxial layers, the material sources must be extremely pure and the entire crystalline growth process must take place in an ultra-high vacuum environment. Also, in order to finely control the deposition of material, the flow of the molecular beams must be precisely controlled. This is generally accomplished using shutters that can open and close in a fraction of a second. Fast shuttering and slow effluence rates makes possible the transition of one material to another at levels which only partially complete an atomic layer. The abrupt epitaxial transitions which can thus be achieved with MBE can be alternated to achieve superlattice structures, wherein some anomalous and highly desirable electrical, optical and magnetic properties may appear.
Most commercial and research MBE machines include at least two major components: a growth chamber and a load chamber. The load chamber is used to bring substrate wafers into and out of the machine while maintaining the vacuum integrity of the growth chambers. The load chamber is also used for the preparation, manipulation, and storage of substrate wafers. The growth chamber is where the MBE process is performed upon the substrate wafers. Effusion cells containing source materials are generally attached to and extend outward from the growth chamber. For certain source materials with very high melting points, electron beam cells may replace effusion cells.
One of the initial problems that was overcome in the design of MBE machines is the transport, storage, and manipulation of substrate wafers. A considerable length of time is required to purify and reestablish a vacuum within the growth chamber once the chamber is opened to the ambient atmosphere. Far less time is required to reestablish a vacuum in the load chamber section once it is opened, provided that the growth chamber remains closed. This is achieved by the use of an air lock between the growth chamber and load chamber. MBE machines have thus been designed so that wafers can be loaded and unloaded without the loss of vacuum in the growth chamber. Wafers are first loaded into the load chamber with the air lock between the load chamber and growth chamber closed. Once the load chamber again reaches a vacuum state, the air lock is opened so that wafers can be moved into the growth chamber. A transport system may be used to move the wafer or wafers through the load chamber. One example of such a system is a chain-driven cart that travels the length of the load chamber. Once the cart reaches the end of the load chamber nearest the growth chamber entrance, a magnetically coupled transfer arm can be used to carry the wafer or wafers lying in the cart from the load chamber into the growth chamber. The arm may be magnetically manipulated by a user situated near the MBE machine. Generally, the arm travels just into the load chamber when retracted, but may be extended into the growth chamber when pushed inward.
The load chamber may also include a vertically oriented manipulation arm, commonly referred to as a “wobble stick,” which is generally used to move wafers to and from the load chamber transport means and the magnetically coupled arm. Once the wobble stick has transferred the wafer from the transport means to the magnetically coupled arm, the air lock between the load chamber and growth chamber is opened, and the magnetically coupled arm is extended into the growth chamber to load the wafer into the wafer holder.
The wafer holder in the growth chamber must be heated to maintain the proper temperature at the crystalline substrate wafer. The exact temperature required will depend upon the materials being used. In some systems the wafers are loaded into the growth chamber in an orientation that faces away from the material sources initially, so the wafer holder must flip around to face the wafer toward the material sources before material deposition may begin. The substrate wafer holder and other components that are to be heated must be made of materials that do not decompose or outgas impurities even when heated to high temperatures; such materials as Tantalum (Ta), Molybdenum (Mo), and pyrolytic boron nitride (PBN) have been used for these applications.
MBE machines may be either solid-source or gas-source. Gas-source machines have the advantage of easier reloading of the source material, since all that is required is the replacement of a pressurized bottle holding the gas source material. For a variety of reasons, including output quality and suitability, for some applications solid-source machines are preferred over gas-source machines. There are, therefore, certain MBE applications for which only solid-source materials are used. The solid source material is sublimated within the effusion cell by applying heat. The flux travels out of the effusion cell into the growth chamber as the shutter to the effusion cell opens. In gas-source MBE machines, the sublimation step is of course unnecessary, since a pressure regulator forces the flow of material which is already in the gaseous state to the substrate.
In solid-source MBE machines, the material sources are generally held in PBN crucibles contained within the effusion cells. Each effusion cell may be heated independently to reach the desired flux of the particular material located in that cell. Small changes in flux can significantly affect the epitaxial layer deposition process for some materials, and thus highly accurate thermostats must be used on the effusion cell heaters. Also, the control shutters that open and close the flow of flux from the effusion cells may be computer controlled to allow the cells to be opened and closed quickly and precisely. It should be noted that most MBE machines may accommodate a number of different effusion cells attached to the growth chamber housing, such that numerous types of source materials may be evaporated simultaneously. Since the properties of each material differ, the specific design of each effusion cell must be different in order to properly handle the particular material in question.
Generally, commercial effusion cells may only be heated to a temperature of approximately 1300° C. before the PBN crucibles begin to disintegrate. For this reason, some materials cannot be placed in effusion cells because the temperature required to vaporize such materials is too great. Iron (Fe) is an example of one such material. When such materials are to be used, electron beam cells replace the effusion cells. Electron beam cells vaporize source material by exposing the source material to highly energized electrons. In one configuration, a rod of the source material is placed parallel to a filament. A large current is then run through the filament until, due to the filament's high resistivity, it is heated to a very high temperature. A potential difference is then applied between the filament and rod such that electrons are drawn from the filament toward the rod. These highly energized electrons then strike the surface of the source material, causing it to vaporize.
One of the most significant problems still faced by those using solid-source MBE machines is the long delay caused by the reloading of source materials into the effusion cells and electron beam cells. Typically, the growth chamber of the MBE machine must be “vented” (brought up to atmospheric pressure and opened) in order for the cells to be reloaded. Once the source material is used up, the machine is then opened, and each cell is removed so that it may be carefully reloaded by hand. In the case of effusion cells, the delicate PBN crucible within the cell must be refilled with source material. The growth chamber must again be brought to ultra-high vacuum and the environment purified in order to proceed with the MBE process after reloading of source material. Because of the extreme levels of purity and vacuum necessary for the operation of MBE machines, this process requires a substantial amount of time. It is believed that an approximate average for most solid-source commercial production MBE machines building GaAs crystals is a source material reloading downtime of approximately one month for each three months of operation. The cost of this reloading downtime includes not only the cost of labor and materials to perform the repurification of the growth chamber, but also the opportunity cost of missing one month of production, or the cost of purchasing a duplicate machine to continue producing materials while the other machine is undergoing the repurification procedure.
Several solutions to the source material reloading problem have been suggested in the prior art. One solution is to use gaseous source materials rather than solid materials. As already explained, gaseous source materials are not used for some applications. Another partial solution is to simply increase the size of the effusion cell so that it may hold a larger source sample. The principal MBE machine manufacturers have continued to increase sample size with each new generation of MBE machine, but it is believed that the ability to continue increasing sample size has approached its practical limit. For some materials, such as Ga, the size of the sample will affect the ability to maintain accurate temperature control, and thus will effect the quality of the molecular beam. As a result of this problem, the sample size cannot be increased indefinitely without affecting the operation of the machine. Also, as sample sizes increase, powered equipment is necessary to move and load the samples, greatly increasing the cost and complexity of MBE machines.
Another solution that has been attempted is to reload the cells from the back (that is, the end extending outward from the growth chamber) without venting the growth chamber. If an air lock and means to translate the cell is placed between the effusion cell and the chamber, such that the cell can be backed away and sealed from the growth chamber, then the cell can be opened and the material can be placed into the effusion cell by hand without losing the vacuum on the growth chamber. This approach does, however, have several disadvantages. First, since each cell contains a different type of material, the hardware necessary to perform reloading of each cell would necessarily be specialized to that particular cell. A machine with twelve different effusion cells, for example, may require twelve different hardware systems to perform this “back loading” operation, which would greatly increase the cost, complexity, and reliability of the machine and reloading procedure. Second, this approach would require that the cell be removed each time the material is reloaded. As a result of exposing the entire cell to the atmosphere, a lengthy purification process is still required before normal operation of the MBE machine can resume. Finally, this approach would only allow access to the cell during the source material reloading process, and would not allow simultaneous maintenance and cleaning of the growth chamber, or any other maintenance operations on the front side of the air lock separating the cell from the growth chamber. Therefore, a means to reload source material in maintained environments, including the ultra-high vacuum environments of solid-source MBE machines, where the growth chamber need not be vented and cleaning and maintenance within the growth chamber may be performed, is desired.
SUMMARY OF THE INVENTION
The invention comprises an apparatus and method to perform activities in a vapor phase deposition environment, like a vacuum environment found in a solid-source MBE machine, by the use of a tool inserted through a port on the load chamber and extending into the growth chamber; or attached directly to the growth chamber. Such tools can thus be used to reload every effusion or electron beam cell in an MBE machine. The tools are constructed of a material, such as Tantalum or Molybdenum, that can withstand the temperatures typically encountered in MBE machines without outgassing impurities.
One of the tools may include a solid source material reloader for easily melted materials. This tool may preferably be formed in the shape of a tube or cone with a small hole in the bottom. The tube is designed to receive solid source material. The handle of the tool is attached to a magnetically coupled transfer arm, similar to those employed in MBE machines to move substrate wafers into and out of the growth chamber. The handle may also be attached to a magnetically coupled transfer arm designed particularly for this purpose, which replaces the standard magnetically coupled arm used for substrate wafer loading. By manipulating the magnetically coupled arm, the tool can be moved such that the tube enters the desired effusion cell. The heater located within the effusion cell may then be used to heat the tube such that the surface material within the tube melts, and runs through the small hole in the base of the tube into the crucible located within the effusion cell. If necessary, an additional heater can be added to the tool to provide more heat to melt the source material.
For reloading solid source materials that are not easily melted, an “on-axis” embodiment of the invention features an L-shaped support attached to either a handle or the magnetically coupled arm. The support has a compression clamp at its end which holds the solid source material in place. A wire is connected at one end to one side of the compression clamp, and at its other end to the magnetically coupled arm. Once the source material is in position relative to the cell for placement, the magnetically coupled arm may be turned about its axis, such that the wire pulls one side of the compression clamp, thereby opening the clamp and releasing the source material into the cell.
In another embodiment of the invention used for reloading solid source materials that are not easily melted, an “off-axis” design features an L-shaped support that is rotateably mounted to either an attachment or the magnetically coupled arm. A wire extends from the L-shaped support to the magnetically coupled arm, such that turning the arm about its axis causes the L-shaped support to raise or lower. The compression clamp on this embodiment features two wings extending from the back part of the clamp, whereby the wings are long enough such that their wingspan exceeds the diameter of the opening to the cell of interest. To load the source material into a cell, the clamp is directed into the cell until the wings strike the opening of the cell, thereby bending each side of the clamp until the source material is released into the cell.
In a still further embodiment of the invention that is a hybrid of those two embodiments described above, both the L-shaped support and a side of the compression clamp are connected to control wires. The control wire to the compression clamp extends back to the magnetically coupled arm and can be controlled as described above to release the source material into a cell. The wire extending to the L-shaped support may be connected to other control means within the MBE machine, such as a cart used to transport materials within the buffer chamber of the machine. Thus by moving the cart forward and backward, the operator may raise and lower the L-shaped support so that it may be aligned with a cell for source material reloading.
Finally, the source material reloading processes described above may incorporate either a one-port or two-port operation technique. The single-port method, using a buffer chamber in connection with the growth chamber, has already been described. In the two-port method, a buffer chamber or load-lock device is attached to the growth chamber. In the case where source material is being reloaded, that material is moved into the load lock, the load lock is brought to a vacuum, and then the load lock is opened such that a passageway exists between the growth chamber and load lock. The reload or other tool is located in a port roughly opposite the load lock. The tool may be attached to a magnetically coupled arm, or to a wobble stick that is attached to the port. Using the magnetically coupled arm or wobble stick, the tool is pushed into the load lock to retrieve the source material, and is then extended over to the cell for loading as explained above. Generally, the geometry of such a machine would have the port for the magnetically coupled arm or wobble stick on one side of the growth chamber, and the load lock and cell to be loaded on the other side of the growth chamber.
It is therefore an object of the invention to provide a tool and method for reloading and maintaining an apparatus without affecting the environment maintained within the apparatus, for example, having an ultra-high vacuum environment without venting the environment.
It is a further object of the invention to perform source material reloading in an MBE machine without translation of the cells being loaded.
It is a further object of the invention to provide a tool and method to reduce the down-time resulting from the reloading and maintenance of an MBE machine.
Further objects and advantages of the present invention will be apparent from a consideration of the following detailed description of the preferred embodiments in conjunction with the appended drawings as briefly described following.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of an MBE machine for use with a preferred embodiment of the invention.
FIG. 2 is a perspective view of a source material reloading tool for easily melted material according to a preferred embodiment of the invention.
FIG. 3 is a partial cut-away view of a source material reloading tool for easily melted material in the load chamber of an MBE machine according to a preferred embodiment of the invention.
FIG. 4 is a partial cut-away view of a source material reloading tool for easily melted material extended into the growth chamber of an MBE machine for the purpose of reloading source material into an effusion cell according to a preferred embodiment of the invention.
FIG. 5 is a partial cut-away view of a source material reloading tool according to an “on axis” preferred embodiment of the invention.
FIG. 6 is a partial cut-away view of a source material reloading tool according to an “off axis” permanent compression preferred embodiment of the invention.
FIG. 7 is a partial cut-away view of a source material reloading tool according to an “off-axis” variable compression preferred embodiment of the invention.
FIG. 8 is a partial cut-away view of a source material reloading tool used in conjunction with a two-port growth chamber design according to a preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, the general layout of an MBE machine will be described in which the present invention may be used. Growth chamber 10 is connected to load chamber 12 through load chamber air lock 18 . Wafer holder 20 is connected to a side wall of growth chamber 10 , while effusion cell 22 is connected to the back wall of growth chamber 10 (only one effusion cell 22 is shown for clarity). Cart 34 travels on track 36 to carry items through load chamber 12 and to the entry point of growth chamber 10 . Alternatively, a transversely oriented magnetically coupled arm (not shown) could be used in place of cart 34 and track 36 as a means to transport materials within load chamber 12 .
Referring now to FIG. 2, the preferred embodiment of source material reloading tool 38 for easily melted materials is shown. Reloading tool 38 has a tubular body 44 with a tapered, closed end. Hole 40 is fashioned into reloading tool 38 at the closed end. A stiff wire (not shown) may be attached to the open end of body 44 (opposite hole 40 ) to keep solid source materials inside body 44 from slipping out during the reloading operation. In the alternative, a trap door or any other fastening means may be used to ensure that the source material remains within body 44 during manipulation of tool 38 . Reloading tool handle 46 extends from body 44 and features an attachment point at the end opposite body 44 .
FIG. 3 shows reloading tool 38 mounted on magnetically coupled arm 50 . Magnetically coupled arm 50 extends through side port 32 and thus reloading tool 38 is positioned within load chamber 12 . Handle 46 of reloading tool 38 may be connected by any conventional means, but preferably is clamped in such a manner that reloading tool 38 may be removed from arm 50 without removing arm 50 from side port 32 , thereby allowing a change of tools on arm 50 without venting load chamber 12 . Tools that are not in use may be stored in load chamber 12 so that tools may be changed without venting of load chamber 12 .
The process for reloading easily melted source material in an effusion cell 22 using reloading tool 38 may now be described with reference to FIGS. 1, 3 , and 4 . Although in this example the source material used is gallium, the invention is equally applicable to the reloading of other solid source materials. Load chamber air lock 18 is first closed. Next, load chamber 12 may be vented without losing the vacuum in growth chamber 10 . End port 56 may then be opened. Cart 34 is moved along track 36 to the position nearest end port 56 within load chamber 12 . A block of gallium is placed within cart 34 , and end port 56 is closed. As noted above, the time required to restore load chamber 12 to the required vacuum and purity levels for MBE processes is far less than the time required to restore growth chamber 10 following venting. In practice, it is believed that the time required to restore the environment of load chamber 12 on most commercial MBE machines is about two days, compared to a time of about one month for the restoration of the environment within growth chamber 10 after venting.
Cart 34 , which now contains the gallium source material block, may be pulled along track 36 until it reaches a position in load chamber 12 directly across from side port 32 . Using wobble stick 48 , the operator may remove the source material from cart 34 and place it in reloading tool 38 attached to arm 50 . It should be noted that wobble stick 48 may a so be used to attach reloading tool 38 to arm 50 if it is not already attached, and may in addition be used to disengage any other tools from arm 50 in order to attach reloading tool 38 . The result of.this process is that source material is held in body 44 of reloading tool 38 at the end of arm 50 , within load chamber 12 and aligned with the passage between load chamber 12 and growth chamber 10 . Provided that load chamber 12 has been restored to an ultra-high vacuum environment, load chamber air lock 18 may then be opened so that an open passage is created between load chamber 12 and growth chamber 10 . Arm 50 may be used to move reloading tool 38 forward past load chamber air lock 18 and into growth chamber 10 .
It has been found that a half turn is necessary to properly align reloading tool 38 into position with effusion cell 22 , if effusion cell 22 is located on the lower half of the back wall of growth chamber 10 . When reloading tool 38 is attached to arm 50 , it is aligned such that it is turned slightly upward. This alignment is necessary so that body 44 of reloading tool 38 does not strike objects in load chamber 12 , such as cart 34 , as it travels past them. Once arm 50 has been pushed inward sufficiently such that body 44 of reloading tool 38 enters growth chamber 10 , arm 50 is given a half turn such that body 44 of reloading tool 38 is now pointing downward. This downward orientation is necessary so that body 44 of reloading tool 38 clears wafer holder 20 and is properly aligned to enter effusion cell 22 . The exact alignment of reloading tool 38 with respect to arm 50 will depend upon the configuration of the growth chamber 10 and effusion cell 22 of interest.
As arm 50 continues forward, reloading tool 38 will approach effusion cell 22 as shown in FIG. 4 . Arm 50 is then manipulated such that body 44 of reloading tool 38 enters effusion cell 22 , with hole 40 in body 44 stopping at a point such that it is positioned above the opening in the crucible (not shown) within effusion cell 22 . The heater integrated into effusion cell 22 may then be activated to melt the gallium within body 44 of reloading tool 38 , such that it flows through hole 40 and pours into effusion cell 22 . Alternatively, an additional heat source may be attached to reloading tool 38 such that additional heat is supplied to the source material as needed; an additional heater is not needed for source materials such as gallium, since gallium has a relatively low melting point. Once the gallium has been drained from body 44 of reloading tool 38 , reloading tool 38 is retracted from within growth chamber 10 in the opposite manner to which it was inserted using arm 50 . Load chamber air lock 18 may then be closed, and the MBE process may continue provided that a wafer has been loaded in wafer holder 20 in a conventional manner.
FIG. 5 illustrates a preferred embodiment of the invention incorporating a reloading tool designed for use with materials that are not easily melted. Support 58 , which preferably is formed into an “L” shape, is attached to the end of magnetically coupled arm 50 . At the end of support 58 opposite arm 50 is compression claim 60 . Compression clamp 60 is adapted to hold a block of solid source material firmly between its sides. Clamp wire 62 extends from one side of clamp 60 , through a small hole in support 58 , and is attached at its opposite end to magnetically coupled arm 50 . In operation, this embodiment of the invention is directed toward cell 22 in a manner similar to that described above with respect to reloading tool 38 . When clamp 60 is in place within cell 22 , however, magnetically coupled arm 50 is rotated about its axis by the operator outside of the MBE machine. In this way, the resulting tension on clamp wire 62 causes clamp 60 to open, thereby releasing the solid source material into cell 22 . Magnetically coupled arm 50 may then be retracted in a manner similar to that already described.
Another embodiment of the invention for use with materials that are not easily melted is shown in FIG. 6 . In this embodiment, support 58 is hinged to support 58 , and support wire 66 extends from one end of support 58 to magnetically coupled arm 50 . Thus by turning arm 50 about its axis, clamp 60 attached to support 58 may be raised or lowered for alignment with cell 22 or for avoidance of objects within growth chamber 10 while maneuvering the source material into position. Once clamp 60 is within cell 22 , wings 64 on clamp 60 will strike the outer edge of cell 22 . It should be noted that wings 64 must be designed such that their wingspan is greater than the diameter of the opening leading into cell 22 . As magnetically coupled arm 50 is brought forward further, the pressure exerted by the opening of cell 22 on wings 64 will cause clamp 60 to open, thereby releasing the sold source material into cell 22 .
Yet another embodiment of the invention for use with materials that are not easily melted is shown in FIG. 7 . This embodiment is a hybrid form of the invention shown in FIGS. 6 and 7. Magnetically coupled arm 50 is hinged to support 58 . Support wire 62 is attached to support 58 and arm 50 such that when arm 50 is turned on its axis, clamp 60 attached to support 58 may be raised and lowered. Clamp wire 66 is attached at one end to support 58 , and at its other end to a movable control within the MBE machine. In a preferred embodiment, this movable control may be cart 34 . By moving cart 34 backward and forward, clamp 60 may be opened and closed. Thus when clamp 60 is in position with respect to cell 22 , cart 34 may be moved such that tension is applied to wire 62 , thereby opening clamp 60 and allowing the solid source material to fall into cell 22 .
FIG. 8 illustrates a particular geometry of growth chamber 10 wherein the present invention may be practiced using two ports. In this embodiment, load lock chamber 68 extends from growth chamber 10 opposite port 32 . Load lock 70 functions as an air lock that, when closed, separates growth chamber 10 from load lock chamber 68 . In the case where source material is being reloaded using either reloading tool 38 or clamp 60 as described below, the material may be placed in load lock chamber 68 while load lock 70 is closed. Load lock chamber 68 may then be brought to a vacuum, and load lock 70 opened to form a passage to growth chamber 10 . Reload tool 38 or clamp 60 and support 58 are attached to magnetically coupled arm 50 in port 32 , which is roughly opposite to load lock 68 across growth chamber 10 . In an alternative embodiment, wobble stick 48 may be used instead of magnetically coupled arm 50 to extend through port 32 for attachment of reloading tool 38 or support 58 . Using magnetically coupled arm 50 or wobble stick 48 , the appropriate tool is pushed into load lock chamber 68 to retrieve the source material. The tool is then extended over to cell 22 for loading as explained above. Generally, the geometry of such a machine would have port 32 on one side of growth chamber 10 , and load lock chamber 68 and cell 22 on the other side of growth chamber 10 .
The present invention has been described with reference to certain preferred and alternative embodiments that are intended to be exemplary only and not limiting to the full scope of the present invention as set forth in the appended claims.
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A tool and method for reloading source materials in a vapor phase deposition (VPD) environment is disclosed. The tool and method does not require the venting of the VPD environment in order to perform its functions. The tool may reload source material into effusion cells or electron beam cells of a molecular beam epitaxy (MBE) machine without venting the growth chamber.
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BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The invention relates to leak rate measurements in general and more specifically a system and a method for investigating and quantifying leakage rate of a fluid in an annulus.
[0003] 2. Background Art
[0004] From prior art one should refer to Xu, Rong. (2002). ANALYSIS OF DIAGNOSTIC TESTING OF SUSTAINED CASING PRESSURE IN WELLS (Ph.D. Dissertation, Louisiana State University and Agriculture and Mechanical College). This document describes properties of SCP (Sustained Casing Pressure) in wells, particularly in respect to gas pressure build-up.
[0005] References should also be made to SPE 117961: Ali Al-Tamimi et al (2008). Design and fabrication of a Low rate metering Skid to Measure Internal Leak Rates of Pressurized Annuli for Determining Well Integrity Status.
[0006] This approach suffers from the need to bleed pressure down to zero or as low as reasonably achievable pressure.
[0007] One should also refer to NO20092445, granted as NO331633 and published as WO/2010/151144, relating to a method and an apparatus to investigate and quantify a leakage rate for a fluid between a first pipe and a second pipe, the first pipe being surrounded by at least a portion of the second pipe, where the pipes are arranged in a well in a ground and where a measuring arrangement including a flow meter and a pressure meter is put into fluid communication with an annulus defined by the first pipe and the second pipe, where fluid in the gaseous phase is conveyed through the measuring arrangement, as the annulus is used as a separation chamber for gas and liquid.
[0008] NO20092445 discloses a need for separation of gas and liquid wherein this is achieved using an annulus as a separation chamber, thus eliminating the need for a dedicated separation container in the measurement system. Yet, having supposedly eliminated the need for a dedicated separation container the document still discloses the possibility for gas condensing in the measurement system and precipitating as a liquid due to e.g. temperature drop. This is compensated using heated piping. Tests show that condensation does take place and that heating of the piping is not a simpler or more adequate solution than a dedicated separation container in the measurement system.
[0000] From prior art one should furthermore refer to
[0009] G82483823 relating to leaks in flexible tubing,
[0010] US2011/0247432 relating to mass flow in aircrafts, and
[0011] US 2007/0051511 relating to breach detection in petroleum wells.
[0012] The fluid from the reservoir comprises oil, gas and water on entering a separator and will be mixed due to the fast and turbulent flow conditions in the tubing. In the separator the flow rate will be strongly reduced and thus also the turbulent forces so that gravitational forces will allow oil, water and gas to be separated. The speed of separation of water from oil will be determined by the speed water falls through the oil. The effectiveness of an annulus as a separation chamber will therefore be dependent on the separation process being given sufficient time before fluid is extracted from the annulus to further processing upstream.
[0013] Foaming is a problem and the entire liquid column can be filled with foam once the annulus is bled down and thus occupy a much larger volume than purely “inert” fluid. An echometer will register the top surface of the foam phase and thus yield incorrect information as to how much fluid has flowed in.
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0014] A main objective of the present invention is to provide an improved system and method for investigating and quantifying leakage rate of a fluid in an annulus.
[0015] It has also been realised that the need to bleed pressure down to low pressures, approaching atmospheric pressures, results in a large pressure difference between an annulus and the tubing. Since the tubing and the annuli are long this means a large force arises that can impact the integrity of the structure and increase a leak or even rupture a wall. The inventor has therefore realised the need for an approach that does not involve a large pressure differential.
[0016] It has also been realised that prior art is based on a steady state while using a valve to maintain constant pressure differential. These two aspects are not possible to combine and thus the criteria for true steady state are not really present. With an erroneous premise the method cannot be valid and there is a contradiction in terms.
[0017] Also the annulus itself represents a large volume and is capable of storing and unloading fluids. The volume can be about 30 m 3 . Volume varies and there are known cases of volumes up to 130 m 3 . This means that the flow rate measured at surface may not necessarily equal the flow rate through a leakage point deep down in the annulus. When an annulus is first opened to flow the initial production at surface may come entirely from fluids unloaded from the annulus bore and it may be a considerable time before the surface flow rate equals the leakage point flow rate. The term “considerable time” implies longer than one can normally allow the test to last.
[0018] When an annulus is shut in at surface fluids may continue to flow through the leakage point into the annulus for equally considerable time as the annulus stores fluid—a process commonly known as afterflow.
[0019] These effects are essentially due to the same phenomenon, and are collectively referred to within well test interpretation literature as wellbore storage effects.
[0020] If a test is completely dominated by annulus storage then that data will be useless as a source for leakage analysis. Annulus storage effects must therefore be considered in the design and analysis of an annulus leak test.
[0021] Based on this premise the inventors have discovered a need to find valid methods not requiring large pressure differentials for
[0000] A: determining if a leak into an annulus is through cement or tubing,
B: determining leak rate into annulus through cement, and
C: determining leak rate into annulus from tubing or annulus to annulus
The Primary Need for the Invention
[0022] An operator (an oil company) of an oil/gas well has the duty of performing planned maintenance in order to verify that all barrier elements of the well perform according to purpose. This comprises leak testing of valves installed at certain depths in a well for the purpose of leading gas from the A-annulus and into the tubing to ensure that oil flows from the reservoir to the surface. Such valves are known as GLV (Gas Lift Valves). Such valves are to be closed when there is no pressure difference between the A-annulus and tubing, or there is a higher pressure in the tubing than in the A-annulus. A closed valve has to be seal closed. There will nevertheless be a certain probability for a leak. One reason for this is that tubing and casings are pressure tested using liquid where a minor leak might not be noticed. Later this can arise once the site of the leak is exposed to a differential gas pressure.
Means for Solving the Problems
[0023] The objective is achieved according to the invention by
[0024] a method for investigating and quantifying leakage rate of a fluid in an annulus as defined in the preamble of claim 1 , having the features of the characterising portion of claim 1 ,
[0025] a method for investigating and quantifying leakage rate of a fluid in an annulus as defined in the preamble of claim 2 , having the features of the characterising portion of claim 2 , and
[0026] an apparatus for investigating and quantifying leakage rate of a fluid in an annulus as defined in the preamble of claim 8 , having the features of the characterising portion of claim 8 .
[0027] The present invention attains the above-described objective by the use of a throttle valve for setting a constant cross section opening while operating in choked flow and registering mass flow and change in pressure.
[0028] In a first aspect a method for investigating and quantifying leakage rate of a fluid in an annulus between a first pipe and a second pipe, wherein the first pipe, being surrounded by the second pipe, is provided wherein the method comprises:
[0029] a: bleeding fluid in the gas phase from the second pipe through a first throttle valve to a first mass rate, while operating in choked flow
[0030] b: registering pressure and mass rate response through a first throttle valve over a predetermined period of time,
[0031] c: determine mass rate (Q) and change in pressure (dp/dt)
[0032] repeating steps a-c to obtain at least one more reading.
[0033] In a second aspect a method for investigating and quantifying leakage rate of a fluid in an annulus between a first pipe and a second pipe, wherein the first pipe, being surrounded by the second pipe, is provided, wherein the method comprises:
[0034] x: closing throttle valve,
[0035] y: measure a resulting pressure build up (dp/dt) when Q=0,
[0036] It is preferred that the method of the second aspect is performed subsequent to performing the method according to first aspect.
[0037] In a preferred embodiment an external separation chamber that is integrated with the measurement apparatus is used.
Effects of the Invention
[0038] The technical differences over prior art according to NO331633 is the use of an external separator which is integrated in the measurement apparatus. The technical effect of this is the ability to simultaneously and reliably determine the fluid flow of gas and the fluid flow of liquid, wherein the fluid phases are pure phases which is important to make mass flow of bled gas workable.
[0039] These effects provide in turn several further advantageous effects:
[0040] it makes it possible to avoid bleeding annulus pressure down to zero, which in turn leads to reduced stresses on the tubing and the environment,
[0041] it saves time since it takes a long time to bleed pressure to zero while the present invention requires less time to reach choked flow,
[0042] it is not necessary to assume the process is in a steady state.
[0043] It should also be pointed out that prior art is based on the assumption that flow through measurement system at the surface is the same as the flow through the leak. The weakness in the argument, that the present invention overcomes, is that there is a substantial distance between the two positions of critical flow at the leak and the measurements at the surface. Between these a large amount of gas is stored compared to the rate intended to measure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The above and further features of the invention are set forth with particularity in the appended claims and together with advantages thereof will become clearer from consideration of the following detailed description of an exemplary embodiment of the invention given with reference to the accompanying drawings.
[0045] The invention will be further described below in connection with exemplary embodiments which are schematically shown in the drawings, wherein:
[0046] FIG. 1 shows a typical embodiment of the invention
[0047] FIG. 2 shows a plot of Q vs. dp/dt
[0048] FIG. 3 shows a plot of P and Q vs. t
[0049] FIG. 4 shows an embodiment of a separator
DESCRIPTION OF THE REFERENCE SIGNS
[0050] The following reference numbers and signs refer to the drawings:
[0000]
1
Well
3
Tubing
5
First casing
7
Second casing
9
Third casing
11
Sealing medium, production packer
12
Leak hole (unintentional)
13
Cement
20
Measuring arrangement - fluid flow
22
Fluid communication line comprising a tube
23
First flow meter (coriolis) for gas flow
24
Second flow meter (coriolis) for liquid
25
First pressure sensor
25′
First pressure gauge (readout, recording of data via logging system)
26
Second pressure sensor
26′
Second pressure gauge (readout, recording of data via logging
system)
27
Signal cable between pressure sensor and pressure gauge
(Alternatively wireless communication)
28
First throttle valve - gas flow control
29
Second throttle valve - liquid flow control
30
Measuring arrangement - acoustic liquid level
31
Acoustic signal analyser unit (Echometer)
33
Acoustic signal communication cable (Echometer)
35
Acoustic source (Echometer)
A
A-annulus
B
B-annulus
C
C-annulus
FG
Free gas
FL
Liquid
LL
Liquid surface (Liquid level)
LL A
Liquid surface (Liquid level) in A-annulus
LL B
Liquid surface (Liquid level) in B-annulus
40
Separation chamber
41
Separator temperature sensor
43
Separator pressure sensor
DETAILED DESCRIPTION
[0051] Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.
[0052] The invention will be further described in connection with exemplary embodiments which are schematically shown in the drawings, wherein FIG. 1 shows typical embodiment of the invention as well as the well and related devices such as casings.
Principles Forming the Basis of the Invention
[0053] The inventors have found that when using a throttle valve rather than a constant pressure difference valve the system can be modelled as a pressure reservoir, corresponding to the tubing, connected to a tank having a certain volume, corresponding to the annulus. Fluid under pressure flows from the pressure reservoir through a throttled connection between the pressure reservoir and the tank, wherein the throttled connection represents the leak. The tank is also connected to an outlet which is the apparatus according to the invention, having a throttle valve and means for measuring the mass flow.
[0054] The underlying principle of the invention is to determine the leak rate Q leak by determining a mass flow rate Q for a corresponding rate change in pressure dp/dt when operating in a choked flow. The data points can be fitted to a straight line that intersects the Y-axis representing the leak rate Q through the leak 12 shown in FIG. 1 at dp/dt=0.
[0055] FIG. 2 shows such a plot.
[0056] It will be appreciated that it is necessary with at least 2 data points to plot the line that gives the intercept. Nevertheless it is good practice to measure further data points to make sure that the system operates in the expected choked flow rate and to allow for second order terms of higher to allow for a non-perfect gas. Significant divergences from the expected behaviour indicate deviations from the basic assumptions, for instance that the leak rate is changing significantly over the time period of measuring the data points.
[0057] With this in mind it has been realised that the reduction to practice will result in two substantially different measurement methods that still are embodiments of the same inventive concept.
[0058] In a first embodiment the pressure p is reduced over time t by bleeding the pressure through a throttle valve until entering choked mass flow and then measuring a plurality of data points Q for a corresponding value of dp/dt.
[0059] In a second embodiment the pressure p is increased over time by closing the throttle valve, measuring the pressure buildup when Q=0, calculating Dp/Dt for Q=0.
[0060] The calculation to determine Q leak from the acquired data points can be made in several ways. In a first embodiment of the calculation the Q leak is represented by Q at dp/dt=0, determined by finding the intercept of the Y-axis representing values of Q where the X-axis represents values of dp/dt. In a second embodiment of the calculation the value of Q leak determined as the asymptotic approach of Q.
[0061] FIG. 3 shows a plot of Q vs. time t.
[0062] This method will uncover the leak rate with a significantly higher reliability and accuracy than is obtained in the prior art.
BEST MODES OF CARRYING OUT THE INVENTION
[0063] The embodiment of the apparatus according to the invention shown in FIG. 1 comprises 3 annuli A, B and C separated by tubing 3 and casings 5 , 7 and 9 , in such a way that A-annulus is between casings 3 and 5 and B-annulus is between casings 5 and 7 and C-annulus is between casings 7 and 9 .
[0064] All casings are sealed at the bottom using sealing medium 11 or cement 13 .
[0065] In the embodiments shown the B-annulus is fluid connected to measuring arrangement 20 using a line 22 comprising a tube leading the fluid from the annulus to the measuring arrangement. Signal cables 27 are connected to first pressure sensor 25 attached to A-annulus, and a second pressure sensor 26 attached to B-annulus. These are connected to corresponding pressure gauges 25 ′ and 26 ′ and operable to measuring pressure of A- and B-annulus respectively. Additionally downstream of the measuring arrangement there are provided a throttle valve 28 for gas flow and a throttle valve 29 for liquid flow out of separator.
[0066] The figure shows a leak hole 12 formed in a part of the first casing 5 above liquid level LL A . The hole is undesired and causes fluid flowing from the A-annulus to the B-annulus due to the pressure difference between the two. A liquid level LL B of a liquid FL in the B-annulus forms a separation between liquid FL and gas FG.
[0067] A part of the gas flowing through the measurement arrangement may condense. The condensation depends on pressure and temperature conditions in the annuli and the PVT characteristics of the fluid. The measurement arrangement is provided with a separation chamber for gas and liquid so that only gas is led through Coriolis mass measurement unit 23 . Thus it is not required to use an annulus as a separation chamber.
[0068] Using throttle valve 28 the throttle cross section can be maintained constant while measuring the pressure in the B-annulus and the gas rate Q through the measurement arrangement. It is assumed that the pressure downstream of the leak is less than or equal to half the pressure upstream of the leak, so called critical flow.
[0069] Thus the leak rate Q in terms of mass per unit time of fluid through the leak 12 will be constant. It should be noted that Q represents the mass rate of gas, nevertheless the use of a separator allows for some liquid in the mass flow.
[0070] In FIG. 1 the fluid is a gas. By determining dp/dt at different rates Q one can plot values of Q as a function of dp/dt. The points can be fitted to a straight line that intersects the Y-axis representing the leak rate through the leak 12 at dp/dt=0.
[0071] This method will uncover the leak rate with a significantly higher reliability and accuracy than is obtained in the prior art.
[0072] It is preferred that the properties of the gas are known. Having a single reading it is possible to determine volumetric gas leak rate at standard conditions. This can be determined by having the specific density of the gas as part of the calculations of a volumetric rate at standard conditions.
[0073] Also the measurement arrangement preferably comprises an acoustic measurement instrument 30 comprising a signal analyser 31 connected to acoustic source GUN 35 with cable 33 as shown in FIG. 1 . Together this is referred to as an echometer, or EM.
[0074] The purpose of EM is to provide information regarding changes in the liquid level LL of the B-annulus. This can be used to discover changes in the mutual relationship between gas and liquid in the B-annulus and thus also any liquid leakage through the leak 12 .
[0075] Liquid FL flows through the leak 12 from A to B due to the pressure difference between the two. The pressure difference can also cause some of the liquid to enter the gas phase in the B-annulus.
[0076] Using the throttle valve 28 the throttle cross section can be maintained at a constant level or opening while measuring the pressure in the B-annulus and the gas rate Q through the measurement apparatus. The gas leak rate can be determined as described above. Moreover the liquid leak rate can simultaneously be measured using EM.
Alternative Embodiments
[0077] A number of variations on the above can be envisaged. For instance a need can arise to determine the liquid level in the separator. In a first embodiment the liquid level can be determined by an echo sounder or echometer.
[0078] In a second embodiment, shown in FIG. 4 , the liquid level is determined at specific intervals by the use of pressure gauges. Starting with a separator initially filled with gas and having a lower and an upper pressure gauge connected to the separator at a lower and an upper level respectively, the two pressure gauges read substantially the same pressure. As the separator is filled with liquid the liquid level increases until reaching the connector to the lower pressure gauge the lower gauge starts reading an increased pressure compared to that of the upper gauge. As the liquid level increases further also the upper connector is reached at which point the two pressure gauges read substantially the same difference in pressure. When the liquid is drained from the separator the readout process is correspondingly reversed.
INDUSTRIAL APPLICABILITY
[0079] The invention according to the application finds use in determining leaking that relates to sustained casing pressure (SCP)
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A system and a method for investigating and quantifying leakage rate of a fluid in an annulus are provided. An objective of the present invention is to provide an improved system and method for investigating and quantifying leakage rate of a fluid in an annulus. The present invention attains the above-described objective by the use of a throttle valve for setting a constant cross section opening while operating in choked flow and registering mass flow and change in pressure.
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FIELD OF THE INVENTION
This invention relates to the field of exercise equipment, in particular to exercise equipment used to strengthen abdominal muscles.
BACKGROUND OF THE INVENTION
This invention relates to the field of exercise equipment, in particular to exercise equipment used to strengthen abdominal muscles.
The present invention relates to resistance machines for exercise. The prior art is replete with examples of exercise machines. Exercise machines known in the art, such as weight benches, often comprise a frame with a shaft and a pivot arm attached to it. Weights are loaded on the shaft, and the pivot arm functions as a handle for the person exercising. In some machines, the exerciser has the option of moving the handle to one of several positions before using the machine. This option enables the user to exercise several different muscle groups with the same machine. In order to move the pivot arm of the weight benches presently known in the art, the exerciser must remove the weights on the shaft, adjust the handle and replace the weights before beginning to exercise. This process is tedious and time consuming. The person exercising wastes valuable time removing and replacing weights. An exercise machine that does not require removing the weights to adjust the pivot arm saves exercisers' time and also increases their enjoyment of the machine.
Prior art exercise machines commonly provide weights as a source of resistance. However, resistive force may also be created by different mechanisms. Rubber elements used as stretchable members have been widely used to oppose motion of certain mechanisms in an exercise machine. Many of the resistance mechanisms known in the art are complicated and cumbersome. An exercise machine that is easy to adjust so that different muscle groups can be exercised, and that is simple and durable, would be a welcome improvement.
Many exercise machines are bulky and not only take up space, they are not easily transported or even easily moved within a room. Thus, space must be dedicated to the machine. This may make it less desirable for some exercisers to purchase the machine.
U.S. Pat. No. 4,917,379 teaches an arm extension exercise machine which utilizes a frame-journaled rotating effort arm which is mechanically linked to a frame-journaled rotating weight arm which, together with the frame of the machine and the connecting link joining them, form a simple planar double-rocking-lever four-bar linkage which acts in conjunction with the rotating weight arm to vary the resistive force applied to an operator's arm extending muscles through body-machine contact with the rotating effort arm throughout the range of the exercise movement.
U.S. Pat. No. 5,277,684 teaches a multi-function exercise apparatus that has a base frame including two vertical support members. An adjustable support means is secured to the frame and provides support for a user in a plurality of different upright and horizontal exercise positions. A lever arm is mounted to a fixed shaft extending from each of the two support members, and an elastic band biasing means cooperatively engages each lever arm and corresponding support member thereof so that each lever arm is adapted to have its forward or rearward rotational bias changed without requiring removal and relocation of the lever arm, the corresponding elastic bands, or the corresponding band support pins.
U.S. Pat. No. 5,456,644 teaches an exercise apparatus comprising a frame, a pivot arm mounted on the frame, a resistance mechanism, preferably an elastomeric torsion member, and a positioning element which allows the pivot arm to be pivotally adjusted with respect to the frame, independent of the resistance element, so as to vary the neutral position of the pivot arm. The preferred embodiment may also comprise a shaft mounted to the frame for conveying torque to the elastomeric torsion member and a support arm mounted to the frame to oppose rotation of the elastomeric torsion member about the shaft. In one embodiment, the exercise apparatus takes the form of a weight bench. In a second embodiment, the exercise apparatus is a home gym.
U.S. Pat. No. 5,632,710 teaches an exercise apparatus comprising a frame, a pivot arm mounted on the frame, a resistance mechanism, preferably an elastomeric torsion member, and a positioning element which allows the pivot arm to be pivotally adjusted with respect to the frame, independent of the resistance element, so as to vary the neutral position of the pivot arm. The preferred embodiment may also comprise a shaft mounted to the frame for conveying torque to the elastomeric torsion member and a support arm mounted to the frame to oppose rotation of the elastomeric torsion member about the shaft. In one embodiment, the exercise apparatus takes the form of a weight bench. In a second embodiment, the exercise apparatus is a home gym. In a third embodiment, the exercise machine comprises a frame, a pivot arm pivotally mounted on the frame, the pivot arm having a neutral position, the pivot arm configured to be moveable alternatively by the front and the back of a user's body, and at least one resistance member connected to the pivot arm for creating bidirectional resistance to movement of the pivot arm. In the third embodiment the machine preferably also comprises a seat, for supporting a user rotatably connected to the frame. The invention also includes the method of using the machine to perform various exercises.
U.S. Pat. No. 6,186,926 teaches a seated abdominal exercise machine that includes a frame, a seat mounted to the frame and a backrest attached to the frame rearwardly of the seat. An arm and head support assembly is mounted for rotary movement to the frame and provides a resistance adapted to be moved by an exerciser occupied in the seat. A motion translation arrangement is pivotally mounted between the frame and the arm and head support assembly for providing an unrestricted, full range abdominal crunching motion for the seated exerciser. The machine relies upon a series of transfer members pivotally interconnected together between the frame and the arm and head support assembly and moving about a first fixed horizontal axis passing through the backrest, a first movable horizontal axis passing through the arm and head support assembly, a second fixed horizontal axis passing through the frame at a location offset from the first fixed horizontal axis, and a second movable horizontal axis which moves rearwardly and upwardly relative to the frame when a downward force is exerted upon the arm and head support assembly.
U.S. Pat. No. 6,390,960 teaches a portable exercise device identified for abs and hips conditioning comprising a generally rectangular, rigid frame supporting a tilted seat and laterally aligned, handle bars used for hand bracing when the user is seated thereon. A single lever arm of an elbow configuration is transversely disposed above the seat and is adapted for pivotal lifting which is affected by the thigh movements. The device has a moment means positioned beneath the seat, which means is operatively tied to the lever arm pivot point. Resilient tensioning means are also secured to the frame and provide the variable countervailing force needed to resist the user imposed arcuate movement of the lever arm.
U.S. Pat. No. 6,634,997 teaches an invention that is an improved Pilates chair having a seat top with an underside, a base that is wider than the seat top, a plurality of bracing members between the seat top and the base, a swingable lever having an upper end and a lower end disposed between the seat top and the base, the lower end being hingeably attached from the base, an adjusting block disposed slidably along the lever between the upper and lower ends thereof, means on the adjusting block for locking it in a position along the lever, and one or more elongated helical springs each having two ends, one of the ends being attached from the underside of the seat top, and the other end being attached from the adjusting block, whereby sliding said adjusting block along said lever, and locking it in a position therealong, will result in a greater or lesser extent of stretch being imparted to the at least one helical spring.
U.S. Pat. No. 6,652,430 teaches a training apparatus designed to improve the physical readiness level of the low back and pelvic girdle of an individual includes a frame, a seat, a pivot mechanism mounted on the frame and providing a pivot point, an exercise arm rotatable about the pivot point, and a resistance assembly rotatable about the pivot point. An interlocking mechanism interlocks the exercise arm and the resistance assembly such that they rotate as a single unit about the pivot point of the pivot mechanism. The angle between the exercise arm and the resistance assembly is selectable. The resistance assembly includes at least a first resistance lever arm and, preferably, a second resistance lever arm. The first resistance lever arm includes a counterweight. The second resistance lever arm has a weight attachment mechanism for attaching a stress weight thereto, and the second resistance lever arm is angularly offset from the first resistance lever arm by an angle about the pivot point of the pivot mechanism.
U.S. Pat. No. 6,676,573 teaches a multiple function exercise device that enables simultaneous exercise of several muscle groups. The device includes a chest pad that is stationary to the support frame and a seat that moves in a path of motion that enables the user's chest to remain on the chest pad as the user's legs are extended, thereby causing movement of the seat. This combination provides activation of the leg and hip extensor muscles and the trunk flexor muscles at the same time. In another embodiment, a resistance arm is added that is pivotally attached to the frame and mechanically linked to the seat, thereby causing movement of the arm as the seat moves. This allows the additional activation of the triceps muscles, or elbow extensors of the upper arm, while also working the leg and hip extensor muscles and the trunk flexor muscles all in a single movement. The advantage to such a movement is the time saving effect of working a large group of muscles at one time as opposed to several exercises one after the other.
U.S. Pat. No. 6,984,196 teaches an abdominal exercise machine which includes a seat, which is pivotally linked to a base frame. At least one link includes a handle that can be actuated by a user sitting on the seat. The user presses the handle away from the seat by flexing the trunk muscles of the user. This curls the user's body into a flexed trunk position. As the handle is actuated forward, the linkage arrangement causes the seat to displace upward. This pushes the center of gravity of the user up, thereby doing work and thereby providing resistance to the movement caused by the exercise. The handle may be adjustable in position relative to the link, thereby varying the load used by the user. Foot supports may also be provided either in front of the seat or behind the seat. The foot supports may be mounted to the frame of the seat frame which supports the seat.
U.S. patent application Ser. No. 20010053734 teaches a training apparatus designed to improve the physical readiness level of the low back and pelvic girdle of an individual includes a frame, a seat, a pivot mechanism mounted on the frame and providing a pivot point, an exercise arm rotatable about the pivot point, and a resistance assembly rotatable about the pivot point. An interlocking mechanism interlocks the exercise arm and the resistance assembly such that they rotate as a single unit about the pivot point of the pivot mechanism. The angle between the exercise arm and the resistance assembly is selectable. The resistance assembly includes at least a first resistance lever arm and, preferably, a second resistance lever arm. The first resistance lever arm includes a counterweight. The second resistance lever arm has a weight attachment mechanism for attaching a stress weight thereto, and the second resistance lever arm is angularly offset from the first resistance lever arm by an angle about the pivot point of the pivot mechanism. Also disclosed is a seating and positioning apparatus which includes a thigh engagement device for contacting and restraining an upper surface of a thigh of an individual using the training device.
U.S. patent application Ser. No. 20020142898 teaches an office chair and office desk independently incorporating certain activity features into the chair and desk arrangements allowing the user to perform beneficial exercise without leaving the chair or desk by utilizing movable exercise arms attached to adjustable variable resistance bearing assemblies attached to the chair seat or the desk to provide a full range of omnidirectional exercises.
U.S. patent application Ser. No. 20020183173 teaches a multiple function exercise device that enables simultaneous exercise of several muscle groups. The device includes a chest pad that is stationary to the support frame and a seat that moves in a path of motion that enables the user's chest to remain on the chest pad as the user's legs are extended, thereby causing movement of the seat. This combination provides activation of the leg and hip extensor muscles and the trunk flexor muscles at the same time. In another embodiment, a resistance arm is added that is pivotally attached to the frame and mechanically linked to the seat, thereby causing movement of the arm as the seat moves. This allows the additional activation of the triceps muscles, or elbow extensors of the upper arm, while also working the leg and hip extensor muscles and the trunk flexor muscles all in a single movement. The advantage to such a movement is the time saving effect of working a large group of muscles at one time as opposed to several exercises one after the other.
U.S. patent application Ser. No. 20030078143 teaches an improved Pilates chair having a seat top with an underside, a base that is wider than the seat top, a plurality of bracing members between the seat top and the base, a swingable lever having an upper end and a lower end disposed between the seat top and the base, the lower end being hingeably attached from the base, an adjusting block disposed slidably along the lever between the upper and lower ends thereof, means on the adjusting block for locking it in a position along the lever, and one or more elongated helical springs each having two ends, one of the ends being attached from the underside of the seat top, and the other end being attached from the adjusting block, whereby sliding said adjusting block along said lever, and locking it in a position therealong, will result in a greater or lesser extent of stretch being imparted to the at least one helical spring.
U.S. patent application Ser. No. 20040058790 teaches a training apparatus designed to improve the physical readiness level of the low back and pelvic girdle of an individual includes a frame, a seat, a pivot mechanism mounted on the frame and providing a pivot point, an exercise arm rotatable about the pivot point, and a resistance assembly rotatable about the pivot point. An interlocking mechanism interlocks the exercise arm and the resistance assembly such that they rotate as a single unit about the pivot point of the pivot mechanism. The angle between the exercise arm and the resistance assembly is selectable. The resistance assembly includes at least a first resistance lever arm and, preferably, a second resistance lever arm. The first resistance lever arm includes a counterweight. The second resistance lever arm has a weight attachment mechanism for attaching a stress weight thereto, and the second resistance lever arm is angularly offset from the first resistance lever arm by an angle about the pivot point of the pivot mechanism. Also disclosed is a seating and positioning apparatus which includes a thigh engagement device for contacting and restraining an upper surface of a thigh of an individual using the training device.
U.S. patent application Ser. No. 20070037677 and International Patent Application WO2007092045 teach an exercise chair primarily directed to employing an exercise method, with independent, adjustable foot bars and a foldable configuration. The seat is supported by a plurality of support elements, at least some of which are hingeably connected with the seat, so that the chair can be folded into a compact shape for storage or transport. The independent foot bars may each be attached to a lever that is hingeably coupled with one or more of the support elements. The position of the foot bars may also be adjustable by extending out of the levers and locking into the desired position. One or more resistance elements may be removably attached to a location below the chair seat, and individually connected with the levers via an adjusting assembly that can either slide or be placed in pre-set mounting locations along the lever to provide variable resistance, or can be equipped with a turnbuckle to provide varying resistance. A platform that rests at or near the floor during use may be attached to the two front support elements, which provides stability as well as comfort when the user stands or kneels on the platform when using the chair.
U.S. patent application Ser. No. 20070042880 teaches the construction of a collapsible rotary torso exercise machine. The machine's extended parts fold down and/or detach so that it may be stored in a small space. The machine is also lightweight and therefore portable. Three different types of resistance mechanism are specifically disclosed: 1) piston in cylinder resistance 2) friction resistance and 3) elastic member resistance. The collapsible rotary torso exercise machine preferably has variable resistance and for each type of resistance mechanism disclosed, a mechanism or method for varying the resistance is also disclosed.
U.S. patent application Ser. No. 20070287619 teaches an abdominal exerciser in which the body floats with respect to the exerciser frame, which leads to isolating the abdominal muscles. The exerciser includes a seat; a frame adapted to support said seat in a position that is raised off a floor; a seat pivot connecting said seat and frame, said pivot located under said seat; an upper body arm adapted to engage the upper body of a user; an upper body arm pivot connecting said seat and said upper body arm; and a lower body arm attached to said seat.
European Patent EPO 183635 teaches an exercise machine that includes side frame members. Electromagnetic brakes supported on movable carriages slide along side frame members. Carriages include a hinge for allowing each brake to pivot between multiple positions. Both types of motion allow the output shafts on brakes to be reoriented relative to a support bench on which a user of the machine is located. Various exercise attachments may be coupled to brake output shafts for contacting various body members to perform different exercises. A controller regulates the force levels of brakes.
Much of the prior art relies on bulky weights to provide strength training. These weights must be stored on or near the machine, and are cumbersome to move when adjusting the resistance on the machine. Other prior art consists of machines that are bulky themselves and must be stationarily positioned in a room, where they take up space permanently. Other machines are designed to exercise only one or a few muscle groups, thereby rendering it necessary to buy other machines or means for exercising the remaining muscle groups.
The present invention has advantages that the prior art lacks. In a preferred embodiment, the present invention uses tension bands to provide resistance. Resistance is increased by increasing the number of bands, thus rendering it easy to use and adjust. This speeds workout time and reduces user frustration. The invention is also easily stored and transported in that it can be folded into a relatively compact form. The invention is also versatile; it can be easily employed in a variety of ways with a variety of attachments to provide strength training for a large number of different muscle groups. Additionally, the Core trainer can be adjusted to the size of the user, therefore both small and larger users can employ the same machine correctly, thereby avoiding injuries caused by incorrect use. None of the prior art combines the advantages described above in one machine.
SUMMARY OF THE INVENTION
The present invention is an exercise machine, comprising a support assembly, a seat assembly, a resistance assembly which has a gear wheel fixed to the support assembly, and a resistance arm rotatably attached to the gear wheel. The resistance arm has means to adjustably affix the resistance arm to the gear wheel, and the resistance arm has a resistance attachment means. Also included is an arm assembly having an attachment point, and a resistance band having an end attached to the attachment point and the other end attached to the resistance attachment point.
The present invention is a strength training machine that is versatile, allowing a variety of muscle groups to be exercised using one machine, either with or without attachments. The invention is easy to use and easy to adjust. It is also easily stored and transported in that it can be folded into a compact unit, and it employs light weight resistance means rather than heavy, bulky weights to provide strength training.
It is an object of the invention to provide a means for strengthening a variety of muscle groups using a single machine.
It is an object of the invention to provide a machine for strengthening the abdominal muscles.
It is an object of the invention to provide a machine for strengthening the upper body.
It is an object of the invention to provide a machine for strengthening the lower body.
It is an object of the invention to provide a versatile strength training machine that is easy to use and adjust.
It is an object of the invention to provide a strength training machine that is easily stored and transported.
It is an object of the invention to provide a strength training machine that can be easily customized to the size of the user.
It is an object of the invention to provide a strength training machine that can be easily customized to the needs of the user.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the invention.
FIG. 2 is a front view of the invention.
FIG. 3 is a front perspective view of the invention.
FIG. 4 is a rear perspective view of the invention.
FIG. 5 is a side view of the invention.
FIG. 6 is a bottom perspective view of the invention.
FIG. 7 is an exploded side view of the resistance assembly of the invention.
FIG. 8 is an exploded perspective view of the resistance assembly of the invention.
FIG. 9 is side view of the invention in an alternate form of the embodiment.
FIG. 10 is a top view of the invention.
FIG. 11 is bottom perspective view of the invention in an alternate form of the embodiment.
FIG. 12 is a bottom perspective view of the invention in a folded state.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is perspective view of the invention, core trainer 100 . Core trainer 100 has support assembly 110 , which consists of front legs 120 , rear legs 130 , seat assembly 140 , seat 150 , seat front curved portion 160 , seat rear curved portion 170 , a first handle 180 , and a second handle 190 .
FIG. 1 also shows the resistance assembly 200 , with gear wheel 210 , gear wheel holes 220 , resistance arm 230 , resistance attachment means 240 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm assembly 300 , with arm 310 , arm extension 320 , extension knob 330 , band knob 340 , arm assembly attachment point 350 , press bar 360 , and press bar attachment point 370 .
In the embodiment illustrated in FIG. 1 , a user sits on the seat 150 facing the front of the machine and places his chest against the press bar 360 . He then pushes the bar forward and down using his abdominal muscles. The arm assembly attachment point 350 pivots to allow the arm assembly 300 to move with the press bar 360 while the resistance arm 230 stays stationary and the resistance band 250 stretches, thereby providing resistance to the user. The number and strength of the resistance bands 250 on the resistance assembly 200 determine the intensity of the exercise, and may be varied by the user. The user may brace himself by holding first handle 180 and second handle 190 . There may be one handle, two or more handles, or no handles. Alternately, the handles may be included as a removable attachment.
The user may adjust the core trainer 100 to fit his body or to vary his exercise by adjusting the position of the press bar 360 . This is done by adjusting the arm extension 320 by placing the extension knob 330 in the desired placement hole on the arm extension 320 , which allows the press bar to be placed at varying heights.
Although the figures illustrate the arm assembly 300 and resistance assembly 200 attached to the right side of the core trainer 100 as the user faces the front, the arm assembly 300 and resistance assembly 200 may be attached anywhere on the core trainer 100 , including in any position on the right side, left side, back, or front.
The user may also remove the press bar 360 and replace it with an alternate press bar or other object. This is done by unfastening the press bar 360 at the press bar attachment point 370 , and subsequently attaching the alternate press bar. The press bar 360 may be a horizontal device as shown, or may be a vertical device. It may be any shape or size desired, including but not limited to, a cylinder as shown, a handle-grip bar, a full body bar, a bar that wraps part way around the upper torso, or a bar that allows for attachments, such as exercise bands or other exercise apparatus.
In a preferred embodiment the press bar 360 is a roller, which consists of a metal bar inside a vinyl covered foam pad, but the press bar 360 may be made from any material, including but not limited to, metal, fabric, foam, glass products including fiberglass, wood or wood products including paper products, plastics, rubbers, thermoplastics, and elastomers, or any combination of these materials or other materials that are useful. Also in this embodiment the press bar 360 is in a horizontal position, but it may be used in a vertical position or in any position between the two.
In a second preferred embodiment, the press bar 360 consists of a bar with hand grips. In this embodiment, the arm assembly 300 and resistance assembly 200 are moved using the hands instead of the chest, to exercise the user's arms. The press bar 360 of this embodiment may be horizontal or vertical and may contain hand grips anywhere on it or in it, and there may be multiple hand grips that are either all of the same design or of varying designs.
FIG. 1 also shows the seat 150 with a seat front curved portion 160 and a seat rear curved portion 170 . The curved portion of the seat may be on both front and back, on either front or back, or not present at all. Alternatively, the curve of the seat may be an attachment that is employed only when desired by the user. The seat may employ curved portions that curve upward. Additionally, the curved portions of the seat may be anywhere on the seat, in any combination. For instance, one side of the seat 150 may employ a curved portion, either permanently or as an attachment. The seat assembly 140 may also have an extension that is either an attachment or that is an integral part of the core trainer 100 .
Additionally, the seat 150 may include an adjustment so that it can be moved in relation to the arm assembly 300 . As seen in the drawings, bench adjustment lever 142 can be pulled, allowing seat 150 to move back and forth. The adjustment mechanism 142 is preferably a clamp type bar. When moved to the down position, the clamp, which is a bent metal bar, releases pressure off the sliding seat. The seat can then slide forward or back. It could also be a spring mechanism, or a clamp type mechanism. The seat has a certain travel distance and can be set at any point in that travel.
The primary purpose for the sliding seat is for aligning the gear mechanism, which rotates, as close to rotation point on the body. Ab crunches would have a rotation about the hip. Leg lifts/extensions would have a desired rotation about the knee. In addition a shorter user may desire to have the seat positioned further forward in relation to the arm assembly, while a taller user may want the seat back further. There may also be varying exercises for which the user wishes to adjust the seat position. The seat position may also be altered by means such as, but not limited to, an extension mechanism similar to that of the arm extension 320 , or by other means.
Not illustrated in the figures are various attachments that may be added to the core trainer 100 . One such attachment involves exercise bands that may be attached, for instance to the front legs 120 or rear legs 130 . Alternatively, the exercise bands may be attached to one front leg 120 and one rear leg 130 and the user may sit on the side of the seat, utilizing the exercise bands with hands or legs. These bands may be slipped over the legs, or there may be a built-in ring, pin, or other device for attaching the bands on the legs or anywhere on the core trainer 100 . A further attachment may be wheels on the front legs 120 or rear legs 130 to make it easier to move the core trainer 100 across a surface.
FIG. 2 is a front view of the invention, core trainer 100 . The core trainer 100 is illustrated with support assembly 110 , front legs 120 , rear legs 130 , and seat front curved portion 160 . Also shown from the front view in FIG. 2 is the resistance assembly 200 , with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance attachment means 240 , and the arm assembly 300 , with arm 310 , arm extension 320 , extension knob 330 , band knob 340 , arm assembly attachment point 350 , press bar 360 , and press bar attachment point 370 .
FIG. 3 is a front perspective view of the invention, core trainer 100 . Core trainer 100 has support assembly 110 , which consists of front legs 120 , rear legs 130 , seat assembly 140 , seat 150 , seat front curved portion 160 , a first handle 180 , and a second handle 190 . Although the legs are shown in a partially bent configuration, they could be any shape. Moreover, the legs could be wider or bent outwards. The legs could also have wide pads or “feet” to add stability.
FIG. 3 also shows the resistance assembly 200 , with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance arm 230 , resistance attachment means 240 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm assembly 300 , with arm 310 , arm extension 320 , extension knob 330 , band knob 340 , arm assembly attachment point 350 , press bar 360 , and press bar attachment point 370 .
FIG. 4 is a rear perspective view of the invention, core trainer 100 . Core trainer 100 has support assembly 110 , which consists of front legs 120 , rear legs 130 , seat assembly 140 , sliding bench lever 142 , seat 150 , seat rear curved portion 170 , a first handle 180 , and a second handle 190 .
FIG. 4 also shows the resistance assembly 200 , with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance arm 230 , resistance attachment means 240 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm assembly 300 , with arm 310 , arm extension 320 , extension knob 330 , band knob 340 , arm assembly attachment point 350 , press bar 360 , and press bar attachment point 370 .
FIG. 5 is a side view of the invention, core trainer 100 . Core trainer 100 has support assembly 110 , which consists of front legs 120 , front legs folding joint 122 , rear legs 130 , rear legs folding joint 132 , seat assembly 140 , sliding bench lever 142 , seat 150 , seat front curved portion 160 , seat rear curved portion 170 , and a first handle 180 .
FIG. 5 also shows the resistance assembly 200 , with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance arm 230 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm assembly 300 , with arm 310 , arm extension 320 , band knob 340 , press bar 360 , and press bar attachment point 370 .
The gear wheel 210 may be used to adjust the resistance arm 230 and arm assembly 300 to varying positions from 0 to 360 degrees by selecting the desired gear wheel hole 220 . For instance, the resistance assembly 200 may be attached to the arm assembly 300 on the front side of the core trainer 100 rather than on the backside. This is accomplished by moving the gearwheel adjustment knob 222 to a forward position on the gearwheel 210 by moving it into a forward gear wheel hole 220 .
In FIG. 5 , the gearwheel adjustment knob 222 is in a clockwise position of 11:00. It can be moved to the gearwheel hole 220 that is in the 2:00 position, thereby moving the arm assembly 300 to the front of the core trainer 100 . In this embodiment, the user may pull back on the press bar 360 rather than push on the press bar 360 . This allows the user to exercise different muscle groups by changing the position of the resistance assembly 200 in relation to his body position.
FIG. 6 is an exploded side view of the resistance assembly 200 of the invention. FIG. 6 shows front legs 120 with front legs folding joint 122 , sliding bench lever 142 , seat 150 , seat front curved portion 160 , and first handle 180 . The resistance assembly 200 is shown with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance arm 230 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm 310 , and the band knob 340 .
The resistance band 250 is attached on one end to the arm assembly 300 through the band knob 340 which is on the arm 310 . The resistance band 250 is attached on the other end to the resistance arm 230 through the resistance attachment point 260 . In a preferred embodiment, a resilient band is used to provide resistance. In alternative embodiments, other means may be used to provide resistance, including but not limited to, friction devices, springs, pneumatic devices, torque-oriented resistance mechanisms, electronic resistance mechanisms, magnetic resistance mechanisms, or any other mechanism for providing resistance that may be adaptable to the invention.
The resistance band 250 or other resistance mechanism may be manufactured from any material, including but not limited to, rubbers, plastics, thermoplastics, elastomers, glass such as fiberglass, wood or wood products, fabrics, metals, or any combination of these materials or other materials.
FIG. 7 is an exploded perspective view of the resistance assembly 200 of the invention. FIG. 7 shows front legs 120 , sliding bench lever 142 , seat 150 , and seat front curved portion 160 . The resistance assembly 200 is shown with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance arm 230 , resistance attachment means 240 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm 310 , the band knob 340 , and the arm assembly attachment point 350 .
FIG. 7 illustrates the invention with a plurality of resistance bands 250 , as it may be employed by an advanced user. As can be seen in FIGS. 6 and 7 , adding or removing resistance bands is straightforward, quick, and easy. The user simply removes the band knob 340 , adds or subtracts bands, then replaces the band knob 340 .
FIG. 8 is a side view of the invention, core trainer 100 . Core trainer 100 has support assembly 110 , illustrated with front legs 120 , rear legs 130 , rear legs folding joint 132 , seat assembly 140 , sliding bench lever 142 , seat 150 , seat front curved portion 160 , seat rear curved portion 170 , and a first handle 180 .
FIG. 8 also shows the resistance assembly 200 , with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance arm 230 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm assembly 300 , arm extension 320 , band knob 340 , press bar 360 , and press bar attachment point 370 .
FIG. 8 illustrates one means in which the core trainer 100 may be used to exercise the user's legs. In this embodiment, one exercise the user may perform involves the user sitting on the seat 150 and placing his ankles under the press bar 360 , then lifting up on the press bar 360 . The user may also grasp the handles 180 and 190 to brace himself. Also, comparing FIG. 8 to FIG. 5 , it can be seen that the seat 150 is in a different position. In FIG. 5 the seat has been moved forward, and in FIG. 8 the seat has been moved rearward.
FIG. 9 is a side view of the invention, core trainer 100 . Core trainer 100 has support assembly 110 , which consists of front legs 120 , front legs folding joint 122 , rear legs 130 , rear legs folding joint 132 , seat assembly 140 , sliding bench lever 142 , seat 150 , seat front curved portion 160 , seat rear curved portion 170 , and a first handle 180 .
FIG. 9 also shows the resistance assembly 200 , with gear wheel 210 , gear wheel holes 220 , gearwheel adjustment knob 222 , resistance arm 230 , resistance band 250 , and resistance attachment point 260 . Also shown is the arm assembly 300 , with arm 310 , arm extension 320 , band knob 340 , press bar 360 , and press bar attachment point 370 . FIG. 9 shows that arm 310 can be positioned over seat 150 , and could for example be used for various arm and back exercises.
FIG. 10 is a top view of the core trainer 100 . FIG. 9 shows front legs 120 , rear legs 130 , seat 150 , first handle 180 , second handle 190 , resistance assembly 200 , arm assembly 300 , and press bar 360 .
FIG. 11 is a bottom perspective view of the invention, core trainer 100 . Core trainer 100 has support assembly 110 , which consists of front legs 120 , front legs folding joint 122 , front legs pin 124 , rear legs 130 , rear legs folding joint 132 , rear legs pin 134 , seat assembly 140 , seat 150 , seat front curved portion 160 , seat rear curved portion 170 , and a second handle 190 . FIG. 6 also shows the gear wheel 210 , with gear wheel holes 220 , and press bar 360 .
FIG. 12 is a bottom perspective view of the core trainer 100 . FIG. 11 shows support assembly 110 , with front legs 120 , front legs folding joint 122 , rear legs 130 , rear legs folding joint 132 , seat 150 , seat front curved portion 160 , seat rear curved portion 170 , second handle 190 , and press bar 360 .
FIGS. 11 and 12 illustrate advantages inherent in the seat assembly 140 . The front legs 120 and rear legs 130 may be folded such that, when combined with the proper positioning of the arm assembly 300 , the invention folds into a compact unit that is easy to store and transport. The folding mechanism for the legs may be any number of mechanisms, including but not limited to, a joint that locks in place when the legs are extended, a pin mechanism that holds the legs in the desired position, or an axle.
Another feature of the core trainer 100 is that the front legs 120 and rear legs 130 may be adjusted to allow for users of varying heights. A knob may be employed that allows the user to adjust the angle of protrusion of the legs from the seat assembly, thus varying the height of the seat.
The core trainer 100 employs knobs in various places. The term ‘knob’ is meant to apply to joining devices that may be knobs or any other suitable object, of any shape, and employed in any manner, including but not limited to, screw in devices, push in devices, spring-pressured devices, or any type of method or device that allows the core trainer parts to be joined.
All of the components of the core trainer 100 may be made from any materials deemed suitable, including but not limited to, metals, fabrics, rubbers, plastics, thermoplastics, elastomers, wood or wood products, glass or glass products, animal products, or any combination of these materials or other materials.
The overall dimensions of the core trainer 100 may vary. It is contemplated that the invention may be made in different sizes for men and women, or in a smaller size for children. Generally speaking, the core trainer will have an overall height, in a preferred embodiment, of about 1020 mm, with a height to the top surface of seat 150 of about 456 mm. It will also preferably have an overall length, as determined as the distance from the front legs 120 to the rear legs 130 of about 880 mm, and a width of about 635 mm. Of course, these dimensions are given for illustrative purposes only and can be varied substantially.
Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made only by way of illustration and that numerous changes in the details of construction and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.
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The present invention is an exercise machine that is versatile, easily adjustable, and easy to store and transport. The machine may be used by varying sizes of users for a wide variety of exercises to increase strength. The Core trainer is comprised of a seat with a press bar attached to an adjustable arm, which is attached to a resistance arm. The press bar is available in various interchangeable designs. A pivot allows the adjustable arm and resistance arm to be placed in varying positions in relation to the seat to provide for a multitude of exercise options. The Core trainer can be used with a number of attachments, and also folds into a compact unit that takes up a fraction of the space of other exercise machines.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention herein pertains to an awning rod attachment and particularly to a bracket for use with awning rods which are slotted as are conventionally used with awnings in the recreational vehicle field.
2. Description of the Prior Art and Objectives of the Invention
Awnings for recreational vehicles, modular homes, mobile homes and the like have become increasingly popular in recent years and with growing use, customers are requiring more accessories, enhancements and greater convenience. In order to hang lights and other items along the front of the awning, brackets have been devised which slide into preformed awning rod slots. Conventional awning brackets include one bolt attached to a body having an aperture therein. The bolt has a particular diameter and therefore a different bracket must be used for different size awning rod slots. The lack of versatility of the awning bracket has caused great concern and problems for users who may have to replace awning rods or brackets only to determine that the brackets that they purchased are not compatible with the slots of the existing rods or vice versa.
It is therefore one objective of the present invention to provide an awning rod bracket which includes a plurality of cylindrically shaped bolts to fit a variety of awning rod slots.
It is yet another objective of the present invention to provide an awning rod bracket which is easier to use than conventional brackets and which will receive multiple wires or attachments.
It is still another objective of the present invention to provide an awning bracket which includes a plurality of openings or apertures in the body.
Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed presentation is set forth below.
SUMMARY OF THE INVENTION
The invention herein consists of an awning rod bracket which will fit a variety of awning rod slots. The bracket includes a pair of cylindrically shaped bolts having pointed ends to allow easy insertion into the various size awning rod slots. Each bolt is positioned along an opposite side of a substantially planar body portion and each bolt has a different diameter for accommodation of different slot sizes. The body portion also includes a pair of apertures which may be the same or different sizes for reception of metal or plastic hooks as are conventionally used for suspending lighting, electrical wires and other accessories.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 demonstrates one embodiment of the awning rod bracket of the present invention;
FIG. 2 illustrates the awning rod bracket as seen in FIG. 1 in use on a front awning rod of an awning as positioned on a conventional recreational vehicle;
FIG. 3 depicts a close-up view of the awning rod and bracket as shown in FIG. 2; and
FIG. 4 shows an end view of the awning rod as seen in FIG. 2 with the bracket in one of the slots.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred form of the invention is illustrated in FIG. 1 whereby an awning rod bracket of the invention is formed from a polyvinyl chloride or other suitable flexible material. The bracket includes a first bolt which is substantially cylindrically shaped and includes pointed ends. The first bolt may have a diameter of 0.1875 inches and is integrally molded to the body. The body is substantially planar shaped and may have a thickness of approximately 0.125 inches and defines two openings which can be used for accepting S-type hooks or other attachments. The openings may for example, have a diameter of three sixteenths inches although other diameters or sizes can be selected. Also attached to the body is a second bolt which has a diameter larger than the first bolt. The second or larger bolt is cylindrically shaped and has a diameter of 0.25 inches with pointed ends to assist in loading the awning rod as shown in FIG. 4. The first and second bolts add rigidity and structural integrity to the bracket. Also, the pair of bolts allow ease in gripping and installing.
DETAILED DESCRIPTION OF THE DRAWINGS AND OPERATION OF THE INVENTION
For a more complete understanding of the invention and its use, turning now to the drawings, FIG. 1 shows awning rod bracket 10 which may be formed from a flexible material such as a relatively hard polyvinyl chloride, hard rubber, metal or other suitable material. Bracket 10 includes an upper or first bolt 11 which is joined to planar body 12 and also includes a lower, larger second bolt 13. As hereinbefore mentioned, bracket 10 may be formed by injection molding as is conventional in the trade. Body 12 also defines a pair of apertures 14, 14' for accepting "S" type hooks, brackets or other attachments. As would be understood, S-type hooks are useful for stringing electrical lines for lighting and other purposes.
Bolts 11 and 13 are substantially cylindrically shaped and have pointed ends 15, 15', 16, 16' respectively to provide easy insertion into awning slots 17 in awning rod 18 as seen in FIG. 4. To accommodate various size awning rod slots 17, first bolt 11 has a diameter of 0.1875 inches whereas second bolt 13 has a larger diameter of 0.25 inches. As would be understood, various diameters could be used for bolts 11 and 13 whether the same or different diameters as desirable, depending on the particular awning rods for use therewith. By providing two different diameters for bolts 11 and 13, a greater convenience is afforded the user. This structure allows the bracket to be interchangeable between different sized awning slots. Likewise, by having a plurality of apertures in body 12, a greater variety of attachments, S-hooks and the like can be utilized.
Awning 20 as shown in FIG. 2 is assembled with awning rod 18 therein. After sliding an appropriate number of brackets 10 into one or more slots 17, receptacles such as S-hooks are then available for attachment. Brackets 10 can be spaced along awning rod 18 as desired and once the S-hooks are in place an electrical cord having lights or the like therealong can be easily and releasably positioned within the S-hooks without interference or danger to awning 20. In FIG. 2 awning rod brackets 10 are useful on RV vehicle 25 but can also be used on mobile home awnings, patio or porch awnings, on tents and for other assemblies.
The illustrations and examples provided herein are for explanatory purposes and are not intended to limit the scope of the appended claims.
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An awning rod bracket is provided which can be easily slid into preformed slots in awning rods. The bracket includes a pair of bolts opposingly mounted on a planar body which defines openings therein for receiving various types of attachments for supporting electrical cords or the like.
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FIELD OF THE INVENTION
[0001] This invention relates to expansion joints for structures that carry vehicular traffic. The invention has been devised primarily in the environment of parking structures but may find application in other similar structures, for example, bridges.
BACKGROUND OF THE INVENTION
[0002] Parking structures typically are constructed using reinforced concrete slabs to provide a traffic surface. The individual slabs are sized and spaced from one another to allow for relative movement between the slabs, in particular to accommodate expansion and contraction due to temperature changes. In some geographic areas, it is also necessary to accommodate relative movement caused by seismic events.
[0003] Expansion joints are used to cover the gaps between the slabs and prevent infiltration of moisture and debris. In a parking structure, the expansion joints must also be designed to withstand repeated cyclical movement caused by vehicles travelling over the joints. An expansion joint in a high-traffic area such as an entrance or exit ramp must be designed to withstand millions of cycles over its lifetime.
[0004] Another criterion is the ability to withstand lateral shear forces as vehicles move over the joints, and in particular lateral forces imposed on the joints when vehicles brake and/or accelerate with their wheels on the expansion joint.
[0005] In an effort to address these criteria, many different expansion joint designs have evolved, ranging from elastomeric seals that attempt to fill the gap, to cover plates that extend over and cover the gap. Typically, a cover plate is located in shallow recesses that are formed in the respective slabs on opposite sides of the gap so that the top surface of the cover plate is generally flush with the top surfaces of the slabs. The cover plate overlies a pair of rails that are bolted to the slabs in the respective recesses. A trough or water stop is provided in the gap below the cover plate to catch any moisture that might penetrate between the cover plate and the rails.
[0006] The cover plate is self-centering with respect to the gap by virtue of a series of turnbars that are pivotally coupled to the underside of the plate and engaged at their ends in slots that extend longitudinally of the rails. As the slabs move with respect to one another, changing the width of the gap, the turnbars angle more or less acutely with respect to the walls of the gap, maintaining the cover plate centred.
[0007] A drawback to this type of joint is that it is relatively vulnerable to lateral loadings, for example, when a vehicle brakes or accelerates with its wheels on the cover plate. Pivot pins or bolts coupling the turnbars to the cover plate may bend or even shear off.
[0008] Another weakness of this type of expansion joint is vulnerability to water infiltration around the rails that are mounted on opposing faces of the slabs. Typically, each rail is an extrusion that is bolted in place in a recess in the relevant slab. The extrusion is then “back filled” with elastomeric concrete which bonds to the extrusion and to the slab and is intended to seal out moisture. A difficulty with some expansion joints is that the extrusions have profiles that include undercut areas or “pockets” that can be difficult to fill with elastomeric concrete. Concrete is a highly viscous liquid that is poured into place and allowed to set. The highly viscous nature of the material makes it difficult to ensure that undercut recesses in the extrusion are completely filled. If they are not, the elastomeric concrete may tend to shrink or pull away from the extrusion and/or slab, creating areas for water infiltration.
SUMMARY OF THE INVENTION
[0009] An object of the present invention is to provide improvements in expansion joints intended to address at least some of these drawbacks.
[0010] According to one aspect of the invention there is provided an expansion joint for installation across a gap between adjacent slabs of a structure intended to carry vehicular traffic. The joint includes first and second rails for mounting on the respective slabs at opposite sides of the gap and a cover plate dimensioned to overlie the respective rails and cover the gap while permitting relative movement between slabs. A plurality of turnbars are carried by the cover plate and coupled to the respective rails for maintaining the cover plate centered over the gap. Each turnbar has end portions that are coupled to the respective rails for sliding movement longitudinally of the rails in response to relative lateral movement of the slabs. Each turnbar also defines a pivot axis between its ends about which the turnbar turns with respect to the cover plate in response to lateral movement of the slabs. Each turnbar is connected to the cover plate by coupling means that includes socket on one of the turnbar and cover plate and the rotational coupling element on the other. The coupling element and socket are complimentarily shaped to allow turning of the turnbar with respect to the cover plate about the said axis while transferring lateral loads imposed on the cover plate in use directly to the turnbar and into the relevant slab via the rail mounted on the slab.
[0011] Preferably, the coupling between each turnbar and the cover plate is a ball and socket coupling so that the cover plate and turnbar can also tip to some extent with respect to one another. On the other hand, in applications in which tipping is unlikely to occur, the coupling element could, for example, be of cylindrical form. Most importantly, the coupling should provide a solid connection between the cover plate and turnbar so that lateral loads imposed on the cover plate are transferred directly to the turnbar and any propensity for the cover plate to move laterally with respect to the turnbars is minimized.
[0012] Preferably, the end portions of each turnbar are provided by formations that are enlarged with respect to the main, elongate body of the bar that extends between the end portions. The formations preferably are in line with that main body of the bar so that forces imposed on the bar are transmitted directly to the enlarged end portions. The rails in turn preferably define undercut slots that are complimentary to the profile of the enlarged end portions of the bar and that relatively closely accommodate those formations so that there is minimum free play between the bar and the rails. Again, the objective should be to transfer directly to the rails and, from there to the slabs lateral forces that are imposed on the plates and transferred from there to the turnbars. There should be minimal free play between these components.
[0013] Another aspect of the invention relates to the profile shape of the rail of the expansion joint.
BRIEF DESCRIPTION OF DRAWINGS
[0014] In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which illustrate a particular preferred embodiment of the invention, and in which:
[0015] [0015]FIG. 1 is a vertical sectional view through an expansion joint in accordance with a preferred embodiment of the invention;
[0016] [0016]FIG. 2 is a vertical sectional view through the cover plate of the expansion joint; and,
[0017] [0017]FIG. 3 is a perspective view of the expansion joint, partly broken away to show internal structure.
DESCRIPTION OF PREFERRED EMBODIMENT
[0018] Referring first to FIG. 1, an expansion joint is shown generally at 20 installed across a gap “G” between adjacent reinforced concrete slabs “S” of a parking structure. The joint includes first and second rails 22 , 24 that are mounted in respective recesses or rabbets 26 , 28 in the two slabs adjacent respectively opposite sides of the gap. A cover plate 30 is dimensioned to overlie the respective rails 22 and 24 and cover the gap G while permitting relative movement between the slabs S. The slabs may move laterally with respect to one another (narrowing or widening the gap G or in the longitudinal direction of the gap) and vertically with respect to one another. Joint 20 must be capable of accommodating all of those movements, including simultaneous lateral and vertical movement.
[0019] Each of the rails 22 , 24 and the cover plate 30 is an aluminum extrusion of a length appropriate to the length of the gap to be covered. As shown in FIG. 1, the extrusions that define the rails 22 , 24 are of different cross-sectional shapes. This is for illustrative purposes only; in practice, both rails would normally have the same cross-sectional shape. For reasons that will be explained later, rail 22 is the preferred shape; in FIG. 3 both rails are the same (rail 22 ).
[0020] A plurality of turnbars are carried by the cover plate 30 and are coupled to the respective rails 22 , 24 for maintaining the cover plate centred over the gap G. Only one of the turnbars is visible in FIG. 1 and is denoted by reference numeral 32 . In FIG. 3, part of the cover plate 30 is broken away to show three typical turnbars 32 . Two of those bars are shown extending partially outwardly from the rails 22 , 24 , again for illustrative purposes only; the turnbars would never extend outwardly of the rails in normal use of the expansion joint.
[0021] Reverting to FIG. 2, it will be seen that each turnbar has a main elongate body portion 34 with respective formations 36 at its ends, which are enlarged with respect to body 34 . These enlarged end portions are coupled to the respective rails 22 , 24 for sliding movement longitudinally of the rails in response to lateral movement of the slabs S (to narrow or widen the gap G). Each turnbar also defines a pivot axis A-A between the enlarged end portions 36 about which the turnbar turns with respect to the cover plate 30 during such movement.
[0022] In FIG. 3, the turnbars 32 are shown angled with respect to the rails 22 , 24 . If the slabs move towards one another, the angular inclination of the turnbars 32 with respect to the rails 22 , 24 will become more acute as the turnbars pivot about their respective axes A-A. Conversely, if the slabs move apart, the angular inclination of the turnbars will become less acute.
[0023] Each of the turnbars 32 is coupled to the cover plate 30 by a ball and socket coupling 38 which in this case comprises a ball 40 on the turnbar and a socket 42 on the cover plate. As best seen in FIG. 3, the ball is a generally hemispherical formation and the main body 34 has a generally flat plate-like shape. The socket, on the other hand, is formed by respective ribs 44 at the underside of the cover plate that have arcuate surface portions 44 a corresponding to the curvature of the ball 40 . Because the cover plate 30 is an extrusion, the socket 42 engages the ball 40 only at the sides, i.e. in directions transverse to the length of the gap G. Nevertheless, since the concern is to transfer lateral loads from the cover plate 30 to the turnbars, this form of socket accomplishes the desired objective; it is unnecessary to provide what might be called a “full” socket that encircles the ball (though this certainly could be done in other applications).
[0024] In the illustrated embodiment, the turnbar 32 is coupled to the cover plate 30 for turning about axis A-A (and located longitudinally with respect to the cover plate) by a pivot element in the form of a bolt 46 that extends down through the cover plate and is threaded into a complimentarily threaded bore in the turnbar. The bolt head is shown at 46 a and is located within a recess in the top surface of the cover plate 30 . A washer 47 is used under the bolt head to allow head-to-cover plate movement. A rivet could be used as an alternative form of pivot element.
[0025] The illustrated design has the advantage that the spacing between the turnbars can be set simply by drilling holes through the cover plate 30 at appropriate locations. For example, in high traffic areas, it might be appropriate to have turnbars that are very closely spaced, while wider spacings might be acceptable for less travelled locations. That advantage would be lost if the ball and socket arrangement were reversed and the ball provided on the cover plate and the socket on the turnbar, though that certainly is a possibility within the broad scope of the invention.
[0026] The formations 36 that define the enlarged end portions of the turnbars preferably are spherical and are located generally in line with the centreline of the main body 34 of the turnbar, again so that lateral loads imposed on the turnbar are transferred directly to the formations 36 . The turnbars are one-piece metal (aluminum) castings, but could be made in more than one piece, of more than one material and not necessarily cast. For example, the formations 36 and ball 40 may be made of separate components and assembled to the main body 34 of the turnbar.
[0027] Each of the rails 22 , 24 shown in the drawings has a cross-sectional shape that includes a generally circular section undercut channel 48 that extends longitudinally of the inner face of the extrusion, i.e. so that the channels face one another. The channels 48 and formations 36 are sized relatively closely so as to minimize free movement therebetween. Above the “mouth” of each channel is a downwardly directed pointed formation 50 that provides a “drip” point for any moisture that may penetrate below the cover plate. The tip of each drip point 50 is positioned sufficiently inwardly of the inner edge of the respective slab so that any moisture drips into the gap and does not tend to migrate between the rail and the slab. Since the rails are extrusions, the drip edges 50 extend the full length of the gap.
[0028] A water stop or trough 52 is installed in the gap G between opposing faces of the two slabs S. The water stop itself is essentially a conventional elastomeric moulding that is secured to the respective slabs by bolts 54 that are driven into the slabs. Behind the head of each bolt is a retainer element 56 that is continuous along the length of the gap and includes a lip 56 a that laps over the corner of the slab adjacent the relevant rail.
[0029] Outwardly of the respective channels 48 , the two rails 22 , 24 have different profiles. Rail 24 has a lower limb 58 that lies on the bottom surface of the rabbet 28 and through which the extrusion is secured to the slab by concrete anchors 60 . An upper limb 62 of the extrusion is angled upwardly and away from channel 48 so that a cavity having a generally C-shaped inner wall 64 is defined above the concrete anchors. This cavity is filled with elastomeric concrete to complete installation of the expansion joint. While the C-shaped configuration of the inner wall of the cavity may be beneficial in that it allows the elastomeric concrete to “key” into the extrusion, there may also be a risk of air pockets developing as the elastomeric concrete is installed. Accordingly, the configuration of rail 22 may be preferred.
[0030] Referring now to rail 22 , it will be seen that the extrusion defines outwardly of channel 48 what is essentially a closed cavity 66 (as seen in cross-section) from which extends outwardly a bottom limb 68 similar to limb 58 of extrusion 24 , and through which the rail 22 is secured to the slab by concrete anchors.
[0031] A face 70 of the extrusion extends generally vertically upwardly from limb 68 adjacent the heads of the concrete anchors and includes grooves 72 that provide a key for the elastomeric concrete. Thus, face 70 defines with the rabbet 26 , a generally rectangular section cavity 74 that can be directly filled with elastomeric cement with virtually no risk of air pockets developing. As noted previously, air pockets can lead to poor bonding of the elastomeric cement to the extrusion and/or slab and consequent risk of water infiltration. Another advantage of this form of extrusion is that the cavity 66 essentially reduces the volume of cavity 74 , so that less elastomeric concrete is required.
[0032] In summary, the expansion joint provided by the invention presents a number of advantages as compared with the prior art. A primary advantage is that lateral loads imposed on the cover plate 30 are transferred directly to the turnbars 34 and from there into the relevant rail 22 or 24 and into the slab on which the extrusion is mounted. The risk of shear failure between the cover plate and the turnbars is minimized. At the same time, extrusion 22 in particular provides for secure bonding of elastomeric cement to the rail 22 and slab, reducing the risk of water infiltration. The drip edges 50 ensure that any water that does infiltrate between the cover plate 30 and the rails 22 , 24 will be directed into the water stop 22 where it can be controlled and directed appropriately.
[0033] It is of course to be understood that the preceding description relates to a particular preferred embodiment of the invention only and that many modifications are possible within the broad scope of the invention. Some of these modifications have been mentioned previously and others will be evident to a person skilled in the art. It should be noted in particular that extrusions of either form shown in the drawings may be used as part of other expansion joints, for example joints that do not include the ball and socket couplings of the present invention.
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An expansion joint for a parking structure includes first and second rails for mounting on adjacent slabs at opposite sides of a gap therebetween and a cover plate that overlies the rails and covers the gap while permitting relative movement between the slabs. A series of turnbars are pivotally coupled to the underside of the cover plate using ball and socket joints so that lateral loads imposed on the cover plate are transmitted directly into the turnbars, minimizing the risk of shear failure between the cover plate and the turnbars. At the same time, the ball and socket joints allow the cover plate and turnbars to tip with respect to one another. The turnbars have spherical end portions that are received in complimentary channels in the respective rails so that the turnbars maintain the cover plate centered over the gap.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a fiber optic radiation sensor (dose rate meter) and dosimeter and more specifically, to a fiber optic radiation dosimeter for monitoring radiation sources such as ultraviolet, x-ray, gamma radiation, beta radiation, and protons.
2. Description of the Background Art
Thermoluminescent (TL) phosphors have been used for many years to monitor radiation exposure levels. These dosimeters measure the accumulated radiation exposure over a period of time, ranging from minutes, to days to years. Phosphor materials such as metal-ion-activated lithium fluoride (LiF), or calcium fluoride (CaF 2 ) are commonly used in "TLD badges" to monitor personnel exposure to radiation. These dosimeters are generally prepared from powders of the phosphor that are pressed into opaque white pellets. When exposed to ionizing radiation, such as deep ultraviolet, x-ray or gamma radiation, free electrons are generated and are trapped in the material. The electrons remain trapped until a source of heat is applied to the material to stimulate the release of the electrons. The electrons recombine at a luminescence center in the material resulting in the emission of light. The amount of light emitted is proportional to the amount of radiation exposure. TLD phosphors have a number of problems that must be overcome to be used with confidence. TLD phosphors are limited in size because the opacity of the pellet limits the signal to light generated near the surface. As a result, the dimensions of commercial TLD dosimeters are limited, thereby limiting the dynamic range and overall sensitivity of the dosimeter. Although TLD phosphors must be heated in order to function, heating is also the origin of the most significant problems with TLD dosimeters. Heating irreversibly erases the stored information in the dosimeter. Thermoquenching of the signal at elevated temperature reduces the sensitivity. Finally, the sensitivity of the dosimeter changes upon heating such that the sensitivity must be reset before reuse.
Optically stimulated luminescent (OSL) phosphors operate much the same way as TL phosphors except the recombination luminescence is stimulated optically rather than thermally. Thus, OSL dosimeters avoid all of the problems caused by heating in TLD dosimeters. OSL readout of an OSL phosphor typically need not erase all of the stored information, providing the opportunity to perform subsequent OSL or TL readouts of the dose. The sensitivity of OSL dosimeters is not reduced by thermoquenching and it is not changed by the readout since the OSL dosimeter is not heated. Powdered OSL phosphors, however, are still opaque and experience the drawbacks associated with poor optical quality just as in the case of TLD phosphors.
Glasses have been considered previously as potential TLD phosphors since it was recognized that the optical transparency of glass offers the advantage of more efficient light collection. The effectiveness of these glasses for TLD applications has been limited for a number of reasons, including low readout temperatures, low sensitivity compared to crystalline phosphors and low saturation doses. To some extent, these problems were overcome by use of the glasses described in U.S. Pat. No. 5,656,815 to Huston et al, the entirety of which is incorporated by reference herein for all purposes. The glasses described in that patent are highly favorable for TLD dosimetry. U.S. Pat. No. 5,811,822 to Huston et al, issued Sep. 22, 1998 and entitled "OPTICALLY TRANSPARENT, OPTICALLY STIMULABLE GLASS COMPOSITES FOR RADIATION DOSIMETRY" (the entirety of which is incorporated by reference herein for all purposes) describes novel glass phosphor materials that exhibit highly favorable characteristics for OSL dosimetry applications.
Fiber optic coupled remote dosimeters using TLD and OSL phosphors have also been described. One system, described in U.S. Pat. No. 4,999,504, issued Mar. 12, 1991 to Braunlich et al., utilizes powdered TL phosphors attached to the end of a 0.6 mm diameter optical fiber. An absorbing material is applied to one surface of the phosphor and a diode laser is used to heat the absorber which in turn heats the TL material by diffusive heating. This system is described as a remote fiber optic laser TLD system. The performance of the system is limited in several ways. First, the TL material must be very thin, approximately 0.1 mm, to allow the laser heating source to be transmitted through the TL material to the absorber material. As a consequence, in order to attain sufficient TL sensitivity, the diameter of the TL material and the fiber must be fairly large. A similar approach has been described for a fiber optic coupled OSL dosimeter (U.S. Pat. No. 5,030,834, issued Jul. 9,1991, to Lindmayer et al.). In this case, the OSL phosphor powder is attached to the end of a commercial fiber using an epoxy binder. Because of the high degree of scattering in the phosphor powder, only a very thin layer of powder can be used, thereby seriously limiting the sensitivity. U.S. Pat. No. 5,606,163 to Huston et al., the entirety of which is incorporated by reference herein for all purposes, discloses a fiber-optic coupled remote dosimeter that uses a novel laser heated glass fiber dosimeter to accurately measure radiation exposure for doses from ˜1 rad to ˜8000 rad.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an optically transparent, optically-stimulable, radiation sensitive, sensor.
It is another object of the invention is to provide an optically transparent, radiation sensitive, scintillating sensor.
It is a further object of the present invention to make a fiberoptic-coupled remote radiation sensor and dosimeter using an optically transparent, optically stimulated or scintillating radiation-sensitive sensor as the detector.
These and additional objects of the invention are accomplished by an optically stimulable fiber-optic-coupled remote dosimeter that uses a glass matrix including luminescent centers and trapping centers. These glass matrices are fully described in the aforementioned U.S. Pat. No. 5,811,822 to Huston et al In these types of glasses, the trapping centers are capable of storing charges (electrons or holes), for example resulting from ionizing radiation, for extended periods of time. The trapped charges may be optically stimulated to recombine by the application of optical energy, resulting in the emission of light energy. This process is known as optically-stimulated luminescence (OSL). In several embodiments, the glass (e.g., fused quartz, fused silica, alumina glass, or borate glass) matrix includes an alkaline earth sulfide doped with an activator/co-activator pair of samarium and another rare earth element. In other alternative embodiments, the glass (e.g., silica, alumina, or borate glass) matrix is doped with ZnS and copper, lead, manganese, or cerium. In yet another embodiment, a glass (e.g., silica, alumina, or borate glass) matrix is doped with Cu or Ce.
Because they are phosphors, the OSL glasses described above also scintillate when exposed to ionizing radiation. This scintillation advantageously permits the present invention to also serve as a real-time monitor of ionizing radiation. Of course, the specific OSL glass used may be selected to maximize scintillation or optically-stimulated luminescence.
In addition to the optically stimulated luminescent glass dosimeter, the present invention also includes an optical source for providing stimulating light energy at a wavelength that stimulates the dosimeter to emit light at an emitted wavelength; a photodetector for measuring luminescent emissions at the emitted wavelength; and an optical fiber for passing the stimulating light energy from the optical source to the optically-stimulated luminescent dosimeter to stimulate the optically-stimulated luminescent dosimeter to produce optically-stimulated luminescence light from stored energy and for passing the optically-stimulated luminescence light to the photodetector to enable the photoluminescent detector to measure any optically-stimulated luminescent emissions occurring when the optically-stimulated luminescent dosimeter is exposed to the stimulating light energy.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention will be readily obtained by reference to the following Description of the Preferred Embodiments and the accompanying drawings in which like numerals in different figures represent the same structures or elements, wherein:
FIG. 1 is a schematic diagram of the optically-stimulated luminescent dosimeter system of the invention;
FIG. 2 is a first exemplary application of the optically-stimulated luminescent dosimeter system of the invention in the monitoring of nuclear contamination in pipes at a nuclear processing facility;
FIG. 3 is a second exemplary application of the optically-stimulated luminescent dosimeter system of the invention for in vivo radiation monitoring of radiation doses in patients undergoing radiation therapy.
FIG. 4 shows a signal recorded using the fiber-optic coupled OSL dosimeter of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The optically-stimulated luminescent dosimeter system described in this invention utilizes a novel, semiconductor- and/or metal ion-doped glass material that was recently developed by the present inventors and described in the above-noted U.S. Pat. No. 5,811,822 and in U.S. Pat. No. 5,585,640 to Huston et al., the entirety of which is also incorporated herein by reference for all purposes. Exposure to ionizing radiation, such as deep ultraviolet, x-ray or gamma radiation, results in the formation of trapped electrons in the composite glass material. The electrons remain trapped until the glass material is exposed to light at a stimulating wavelength. Upon exposure to light at a stimulating wavelength, the glass emits a luminescent signal.
In a first embodiment, the doped glass material used in the present invention includes a glass matrix incorporating an alkaline earth sulfide doped with an activator/coactivator pair or with the coactivator alone. The activator/coactivator pair includes samarium and an additional rare earth. The coactivator may be any rare earth, other than samarium, that does not absorb at the stimulating wavelength or the emitted wavelength. Indeed, for the purposes of the present invention, using coactivator alone (i.e., the rare earth other than samarium, e.g., cesium or europium) in glasses of this first embodiment provides results at least equivalent to those achieved by samarium/coactivator pairs. For the purpose of the present invention, the use of samarium alone in glasses of this first embodiment tends to provide inferior results. In a second embodiment, the glass matrix includes ZnS doped with copper, lead, manganese, or cerium. In the first and second embodiments, more than one coactivator may be used. In a third embodiment of the present invention, the glass matrix includes copper and/or cerium, and has either no metal sulfide or a concentration of metal sulfide that is lower than a metal sulfide concentration that significantly alters the luminescent and trapping properties of the glass for its intended purpose. That is, a trace of metal sulfide may be present in the third embodiment, so long as the concentration of the metal sulfide is below that at which the glass begins to noticably exhibit effects from sulfide doping.
In the first embodiment, any alkaline earth sulfide may be used as the alkaline earth sulfide dopant. Typical alkaline earth sulfides useful in the glass matrix of the present invention include MgS, CaS, SrS, and BaS.
When more than one co-activator is used, the additional coactivator is typically Eu, Ce, or a mixture thereof. Other rare earths should also be useful, in place of or in combination with Eu and/or Ce, as additional co-activators.
The second embodiment of the present invention also employs a sulfide component and an activator. In this second embodiment, however, the metal sulfide component is ZnS, and only a single activator, such as Cu, Pb, Mn, or Ce is required. In a third embodiment of the present invention, the glass matrix includes Cu or Ce dopants in the absence of a metal sulfide component, or even in the absence of any sulfide component. For the purpose of the present specification and claims, a glass is considered essentially free of a component if the glass lacks an amount of that component sufficient to significantly alter the optical stimulability or radiation sensitiveness of the glass.
In each of the embodiments of the present invention, the optically stimulable glasses are typically prepared by diffusing the dopants (including sulfide components) into the glass matrix. Because the dopants are diffused into the glass matrix, the glass matrix may be either porous or fused (non-porous).
The dopants may be diffused into the glass matrix by a wide variety of methods. For example, if the glass matrix is porous, it may be contacted with a solution of salts of the desired dopant metals for a sufficiently long time to diffuse the salts into the porous glass. Thereafter, the porous glass matrix is dried. In those embodiments that include a metal sulfide component that would be insoluble in the dopant solution used, the dopant solution may contain a soluble salt of the metal portion of the sulfide. After drying, the glass may be sulfided (for example by exposure to gaseous H 2 S at elevated temperatures, typically about 100° C.) to provide the desired metal sulfide diffused into the porous glass. The porous glass matrix is then consolidated and activated, for example using any of the consolidation and/or activation methods described in Huston et al., supra.
In fused glass, the dopants may be diffused, for example, by dipping the fused glass matrix into an organic-inorganic sol gel (e.g., an organosilicate sol gel) including a salt or salts of the dopant metals. The fused glass matrix is then withdrawn from the sol gel at a slow, steady rate to result in the formation of a porous, thin (typically less than about one micron thick) sol-gel film containing the salt or salts. Upon drying (typically at room temperature to about 200° C.), the organic constituents of the film volatilize and/or decompose, leaving behind a porous, film (a high silica film where an organosilicate sol-gel was used) containing the salts. The glass having the porous film thereon may be sulfided (for example by exposure to gaseous H 2 S at elevated temperatures, typically about 100° C.) to provide metal sulfides, if desired. The resulting material is then activated, typically after being placed within a glass (e.g., silica) tube that is then placed within a tube furnace. If sulfiding is not desired, the decomposition and activation steps may be combined, for example, by heating the sol-gel film to a sufficiently high temperature to decompose the organics and diffuse the resulting metal(s) into the glass and activate them. Appropriate conditions for activation are the same as those described for the activation of porous glasses. Of course, the fused glasses made according to the present invention do not require consolidation. Porous glass matrices may also be doped using this sol gel method.
After several doping operations have been performed, the fused glass tube used to hold the glass samples during activation becomes a source of metal ion dopants. Untreated glass (fused or porous) may then be doped and activated by heating to activation temperatures of typically over 1000° C. while inside the previously used glass tube. This effect apparently results from a "seasoning" of the glass with small amounts of the dopant metal ions. During heat treatment, a low vapor pressure of the metal dopant atoms or ions is created that bathes the undoped glass in a doping atmosphere. The metal doping elements diffuse into the fused or porous glass material. Even where the source glass includes metal sulfides, only the metal ions will dope the glass to a significant extent. The concentration of sulfide in the doped glass will be below that at which effects from sulfide doping become apparent. Thus, the resulting glass is essentially sulfide free. The OSL activity of fused glasses may be achieved by repeated heat treatments in the presence of unconsolidated metal sulfide-containing pieces of Vycor™ or other porous glass.
As should be apparent from the above description of doping untreated glasses by heat treatment within a "seasoned" fused glass (e.g., silica, alumina, or borate) tube, the dopants need be present in only minute amounts within the glass to cause significant and useful OSL activity. Thus, it is extremely difficult to quantitatively define a minimum dopant level required to obtain useful OSL properties. The maximum doping level is that at which either the dopants within the glass matrix obtain crystallite sizes sufficiently large to significantly increase scattering, or the OSL effect is significantly attenuated by a self-quenching mechanism.
The dopant salts used in the solutions and sol gels discussed above are typically selected so that the salt is soluble in the solution or sol gel and the anion component of the salt, upon reduction, forms a gas or mixture of gases that are non-reactive, or beneficially reactive, with the doped glass matrix. The concentrations of these salts in the sol gels and solutions may vary widely. For example, each salt is typically present at a concentration of about 0.001 g per 100 ml solution up to its saturation point at the temperature at which the glass matrix is contacted with the solution or sol gel.
The glass matrix provides a mechanically robust, chemically inert phosphor material that is fully compatible with high quality, commercial optical fibers. The material withstands cycling through temperature extremes of up to 1200° C., without any apparent loss in performance. The glass matrix may be doped in bulk form or may be doped in the form of powders or fibers (e.g., glass wool). Also, if desired, a doped bulk glass matrix may be powdered or drawn into fibers.
The optical transparency of the glass provides for applications that are not possible using traditional powder phosphors. Optically transparent OSL glass dosimeters allow for efficient detection of radioactive particles such as α, β and tritium. These particles do not penetrate deeply into the material, but the waveguiding property of the glass provides for efficient detection. The OSL readout process is much faster than thermal readout methods, making possible much faster processing.
The exemplary Cu-doped glass material absorbs ultraviolet light at about 266 nanometers (nm) and emits optically-stimulated luminescence in a broad band ranging from about 400 nm to about 620 nm and has a peak intensity at about 500 nm (with a color that appears to be blue-green). Unlike the thermoluminescent glass dosimeter used in the aforementioned U.S. Pat. No. 5,606,163, the glass used in the dosimeter system of the present invention is not heated and the OSL system is not reliant on heating for its operation. The glass is essentially free of rare earth dopants (such as Nd 3+ ) that absorb a significant fraction of the stimulation light. Trap release is not stimulated thermally by the absorption of light energy. In addition, the OSL signal is not attenuated due to absorption in the blue-green wavelength range by a rare earth ion dopant, as occurs in the invention described in the aforementioned U.S. Pat. No. 5,606,163. In the glass used in the present invention, recombination of trapped electrons results from direct optical stimulation of the trapped electrons, rather than optically induced heating.
A disadvantage in using the laser heated glass is the Nd ions absorb both the stmulation light from the optical source and the thermoluminescence signal light, thereby limiting the length of the sensor element that can be used. This problem in turn limits the sensitivity of the dosimeter. In an OSL dosimeter, an almost unlimited length of OSL glass dosimeter can be used to increase the sensitivity of the system, since the stimulation light from the optical source is absorbed only by radiation populated traps in the glass. These traps are in turn depopulated and no longer absorb the optical source light. Another advantage of the present invention is that it is much faster than the laser-heated TLD approach. Also, the OSL method does not suffer from thermal quenching of the signal as occurs in laser-TLD. There is no heating at all using the OSL approach. Thus, in in vivo applications, there will be no harmful effects due to even modest heating as might be expected for the laser-heated TLD.
The basic dosimetry system in which this novel glass is employed is described in the aforementioned U.S. Pat. No. 5,606,163. The present invention, however, uses the novel optically transparent, optically stimulable luminescent glass described above in place of the laser heated thermoluminescent glass used in that patent. In addition, the present invention includes an alternative dosimetry method using the scintillation light from the fiber-optic coupled OSL. This alternative dosimetry method, which provides a real-time readout, was not practical using the previously disclosed laser heated dosimeters.
FIG. 1 shows a schematic diagram of the Optically-Stimulated Luminescent Fiber Optic Radiation Dosimeter system 1 of this invention. The optically-stimulated luminescent fiber optic radiation dosimeter system 1 includes a remotely positioned, optically transparent, optically stimulated luminescent glass dosimeter 2 attached to an optical fiber or fiberoptic cable 3. The optically-stimulated luminescent fiber optic radiation dosimeter system 1 also includes an optical source 4 a turning mirror 5, a dichroic beamsplitter 6, a focussing lens 7, an optical filter 8, and a photodetector 9. It should be understood that a fiber splitter or optical coupler can be used in place of the dichroic beamsplitter 6.
The optically-transparent, optically-stimulated luminescent (OSL) glass dosimeter 2 contains the optically-stimulated luminescent glass dosimeter material described above.
The material of the optically-stimulated luminescent (OSL) dosimeter 2 may be in the form of a rod, fiber, plate or tube. An end of the glass dosimeter 2 may contain an optional broadband reflective coating 10.
In the operation of the optically-stimulated luminescent dosimeter system 1 of FIG. 1, about 0.8 micrometer (μm) to about 10 micrometer (μm) (typically about 0.8 micrometer (μm) to about 1.2 micrometer (μm)) light from the optical source 4 (which may be, for example, a diode laser in the range of 0.8 micrometer (μm) to 10 micrometer (μm) (typically about 0.8 micrometer (μm) to about 1.2 micrometer (μm)), a gas laser, a molecular laser, a solid state laser, or a lamp) and at an exemplary 800 nanometer (nm) wavelength is reflected by the dichroic beam splitter 6 and focused by the lens 7 into the optical fiber or fiberoptic cable 3 which may be, for example, several kilometers in length. The optical fiber 3 is fused at its far end 11 to the dosimeter glass material of the optically-stimulated luminescent dosimeter 2 so that the dosimeter glass material effectively becomes a part of the optical fiber 3. Thus, the optical fiber 3 directs light energy from the light source 4 to the optically stimulated luminescent material in the OSL dosimeter 2. It is preferable that the OSL glass dosimeter 2 and the optical fiber 3 have substantia lly identical end face configurations at the far end 11 of the optical fiber 3 to maximize the transfer of light energy from the optical fiber 27 into the OSL glass dosimeter 2. The light entering the OSL glass dosimeter 2 stimulates emission of light at a different wavelength to be detected by the photodetector 9.
Optical source 4 can be any type of light source (such as the previously-mentioned exemplary diode laser, molecular laser, solid state laser, or lamp) that can provide light energy at an appropriate light wavelength sufficient to excite the OSL glass material in the OSL glass dosimeter 2 to produce OSL emissions.
The blue-green, 500 nm (in the case of the exemplary Cu-doped glass) optically-stimulated luminescent light in the dosimeter 2 is directed back through the optical fiber 3, collimated by the lens 7 and passed through the dichroic beam splitter 6. When the optional broadband reflective coating 10 is disposed at an end of the glass dosimeter 2, the reflective coating 10 will minimize any loss of optically-stimulated luminescence or scintillation signal light out of the far end of the dosimeter 2 by reflecting it back to the optical fiber 3, and even more signal light will be directed back to the photodetector 9. The stimulating light will also be reflected by the reflective coating, effectively using the pump light twice.
The dichroic beam splitter 6 is designed to transmit the visible 500 nm signal therethrough and reflect the 800 nm light from the optical source 4. The transmitted 500 nm OSL light is filtered by the filter 8 to remove background light (stray light from the optical source) and is detected by the photodetector 9 which is sensitive to light in the range from about 450 nm to about 850 nm. The photodetector 9, which may be a photomultiplier tube, a photodiode or any other suitable photodetector, measures the optically-stimulated luminescent emissions from the OSL glass dosimeter 2.
Optically-stimulated remote dosimetry systems according to the present invention have a variety of applications. These applications, of course, include the same application as described in U.S. Pat. No. 5,606,163.
FIG. 2 illustrates a first exemplary application of the optically-stimulated luminescent dosimeter system of the invention in the monitoring of nuclear contamination in a drain pipe at a nuclear processing facility. Monitoring for contamination in nuclear facilities is an important problem. The OSL glass dosimeter 2 of FIG. 1 is capable of withstanding harsh environments. As shown in FIG. 2, a dosimeter 2 could be could be snaked through a drainage pipe 12 at a nuclear processsing facility to remotely characterize and survey contamination in the pipe. Accurate survey of such contamination in drainliners will significantly reduce the costs and risks associated with remediation as part of the process of decontamination and decomissioning.
The fiberoptic-coupled OSL radiation sensor system 1 is used to detect radioactive contamination in the pipe system as the dosimeter 2 is slowly withdrawn from the pipe 12. Accumulations of radioactive waste 13 at certain locations inside the pipe 12 produce higher OSL or scintillation signal levels in the dosimeter 2 and are detected with the sensor system 1 and displayed on a computer screen 14. By precisely locating the radioactive contamination 13 inside the pipe 12, and removing small sections of the pipe 12 for special processing will greatly reduce the costs of decomissioning former nuclear processing facilities.
The small size of the fiberoptic coupled radiation dosimeter 2 and the flexible nature of the fiberoptic cable 3 allow this sensor to be deployed inside small diameter pipe systems 12. The remote operation of the sensor system 1 provides for improved safety for nuclear clean-up technicians.
FIG. 3 illustrates a second exemplary application of the optically-stimulated luminescent dosimeter system of the invention for in vivo radiation monitoring of radiation doses in a patient 15 undergoing radiation therapy.
Monitoring of radiation doses in a patient 15 undergoing radiation therapy can help to improve the effectiveness of radiation treatments. In this application of the optically-stimulated luminescent dosimeter system 1 of the invention, the fiberoptic-coupled, optically stimulated luminescent dosimeter 2 is used in conjunction with a fiber catheter 16 to introduce the dosimeter inside the body of a human patient 15. In this manner, the optically-stimulated luminescent dosimeter 2 can be directed to a certain portion of the human body that is being exposed to radiation as, for example, in radiation therapy for cancer treatment. The dosimeter 2 can be placed next to a tumor that is being irradiated and provide the physician with an immediate feedback as to how much of a radiation dose that he is applying to the tumor during radiation therapy. The radiation dose can be read out while the radiation exposure is in progress or after the exposure has ceased. This would allow more precise control of radiation doses and help reduce collateral damage to healthy tissues.
The optically-stimulated luminescent dosimeter system described above is an all-optical radiation sensing system. The optically-stimulated luminescent glass material in the dosimeter system is sensitive to ionizing radiation. The readout of the material is optically stimulated by an extremely small absorption of semiconductor laser light. The laser light is directed to the OSL material by way of a fiberoptic cable. The OSL material is transparent to the OSL emission wavelengths (420 nm-550 nm) and this light is directed back to a detector by way of the same fiberoptic cable. The readout of the material is also achieved by measuring the scintillation from the material during radiation exposure.
The optically-stimulated luminescent dosimeter system offers fast, in-situ readout. The glass dosimeter material does not have to be placed in a separate OSL machine for analysis.
The dosimeter material is optically transparent to the OSL emission wavelengths. The glass dosimeter material can be any arbitrary size or shape, thus increasing the sensitivity of the OSL glass dosimeter.
The OSL dosimeter system is fiberoptic coupled.
The OSL dosimeter system can be operated by remote control, thus minimizing the exposure of workers to radiation sources.
The OSL glass dosimeter of the OSL dosimeter system can be placed in severe environments and will withstand temperatures in excess of 800 degrees C. The OSL glass dosimeter is not moisture sensitive and can withstand corrosive environments.
The OSL glass dosimeter material is inexpensive, easy to synthesize and achieves reproducible performance.
Having described the invention, the following examples are given to illustrate specific applications of the invention including the best mode now known to perform the invention. These specific examples are not intended to limit the scope of the invention described in this application.
EXAMPLES
A radiation sensitive glass sensing element was fabricated from a 1 mm long, 0.4 mm diameter fused quartz fiber that was doped with Cu +1 ions. This small piece of doped fiber was attached to the distal end of a 10 m long, 0.4 mm core diameter commercial optical fiber to yield the fiberoptic-coupled dosimeter used in this work. Typically, 0.1 W of 790 nm light from a solid state diode laser was injected into the fiberoptic-coupled dosimeter to stimulate the release of charges that had been trapped by prior exposure to ionizing radiation. A fraction of the 500 nm OSL signal light, generated by the radiative recombination of the released charges, was directed by total internal reflection back through the fiber, collimated with a lens, transmitted through a dichroic beamsplitter and detected with a photomultiplier tube. Color glass filters were used to isolate the blue-green OSL signal light from the near infrared stimulation light.
Experiments were conducted using radiation from a Varian Clinac 20 (15 MV) beam therapy machine. This machine provided radiation at dose rates variable from 100 cGy/min up to 500 cGy/min. The total dose could be set from 1 cGy to 999 cGy. All of the experiments were performed using a solid water phantom and each dose was calibrated using a microionization chamber at a reference position inside the phantom directly below the fiberoptic dosimeter.
FIG. 4 shows a real-time plot of the response of the dosimeter as the dose rate of the Clinac 20 was varied from 500 cGy/min to 300 cGy/min to 100 cGy/min. The periodic spikes represent a series of 1 second duration OSL readouts performed every 10 seconds during the exposure. The elevated baselines are due to the prompt scintillation signal from the radiation sensitive glass. The integrated area under each successive OSL peak provides the dose rate in terms of dose per integration period. The integrated signals from a series of OSL measurements obtained every 10 seconds over a 3 minute time span were constant to within 2% from start to finish. The total accumulated dose can be obtained by summing the individual 10 second dose increments.
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.
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An optically-stimulated luminescent radiation dosimeter system for the ree monitoring of radiation sources is disclosed. The system includes a radiation-sensitive optically-stimulated dosimeter which utilizes a new, doped glass material disposed at a remote location for storing energy from ionizing radiation when exposed thereto and for releasing the stored energy in the form of optically-stimulated luminescent light at a first wavelength when stimulated by exposure to light energy at a stimulating second wavelength. The system further includes: an optical source for providing stimulating light energy at the stimulating second wavelength; a photodetector for measuring optically-stimulated luminescent emissions; and an optical fiber for passing the stimulating light energy from the optical source to the optically-stimulated luminescent dosimeter to stimulate the optically-stimulated luminescent dosimeter to produce optically-stimulated luminescence light from stored energy and for passing the optically-stimulated luminescence light to the optically-stimulated luminescent detector to enable the photodetector to measure any optically-stimulated luminescent emissions occurring when the optically-stimulated luminescent dosimeter is excited by the light energy at the stimulating second wavelength. Also, the dosimeter can be used for real-time monitoring by detecting the scintillations emitted by the doped glass material upon exposure to ionizing radiation.
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RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent Application Ser. No.: 60/949,111, filed Jul. 11, 2007 and U.S. Provisional Patent Application Ser. No.: 60/974,634, filed Sep. 24, 2007, the disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Hanging luggage is described with a foldable shelf, a lighted mirror and removable containers for containing various items such as toiletries, cosmetics, personal care items, accessories, jewelry and other similarly sized items. The removable inserts may be added, removed or reconfigured by the user of the luggage to customize it to suit personal taste and the specific needs of a use for the luggage.
SUMMARY OF THE INVENTION
[0004] The hanging luggage described herein provides for several features in combination to provide an improved article of luggage for transporting, storing and utilizing various items for personal use, such as cosmetics, personal care products, toiletries, fashion or other accessories, jewelry, medicines, small personal care appliances, and other similar items. The luggage may be used to carry and access any items that may fit into the provided containers.
[0005] The luggage includes a folding hanger for hanging the luggage while packing, unpacking, or utilizing the items contained in the luggage, and which may be folded into the luggage during carrying or other transportation. The folding hanger may also incorporate a mirror to provide an aide for using cosmetic items, or other personal care items stored in the hanging luggage. The mirror may be optionally lit by light fixtures incorporated into the folding hanger or other areas of the luggage.
[0006] The luggage also includes a folding shelf for conveniently setting items during their use, and which may also be folded flat inside the luggage when preparing the luggage for travel.
[0007] The luggage further provides a number of containers or inserts incorporated into and attached to the luggage. The containers may be of varying sizes and shapes to accommodate storage of various items. Some of the containers or inserts may be removably attached to the luggage to allow for use separate from the luggage. The removable containers allow the user of the luggage to add, remove or reconfigure the containers in the luggage thereby customizing it to serve a specific need or the personal taste of the user.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic view of the hanging luggage in an open, hanging configuration.
[0009] FIG. 2 is a schematic view of the hanging luggage in a partially folded configuration with several of the removable inserts disconnected from the hanging luggage panels.
[0010] FIG. 3 is a partial photographic view of an embodiment of the hanging luggage in an open, hanging configuration.
DETAILED DESCRIPTION
[0011] Referring to FIG. 1 , the hanging luggage 100 is shown in an open configuration. The luggage 100 comprises a top panel 102 and at least one folding panel 104 . The embodiment shown in FIG. 1 includes two folding panels 104 , however other embodiments of the hanging luggage 100 may have one or more folding panels 104 . The embodiment shown in FIG. 1 has two folding panels 104 , with a first folding panel 104 foldably attached to the bottom edge of top panel 102 , and the second folding panel 104 foldably attached to the bottom edge 107 of the first folding panel 104 . The relative proportions of the folding panels to each other and to the containers and removable inserts therein may or may not be as shown in the figures.
[0012] Top panel 102 and folding panels 104 may be constructed utilizing a number of methods and using a variety of materials as known in the art of making luggage. The panels may be constructed from cloth over a frame, stiff materials such as leather, plastic or synthetic materials, or hard-side materials commonly used to construct suitcases. Either the top panel 102 or the folding panels 104 , or both, may have side walls 109 extending substantially perpendicular to the panels 102 and 104 , the side walls defining an open-sided box with a depth typical of luggage or garment bags, as further described in relation to FIG. 3 .
[0013] The top panel 102 and the folding panels 104 are foldably attached together along an exterior edge 106 of the panels to allow the folding panel 104 to overlay the top panel 102 in a folded configuration of the luggage. The top panel 102 folds into and is enclosed by the first folding panel 104 . The first folding panel 104 and the second folding panel 104 fold together and fasten along exterior edges 108 .
[0014] The top panel 102 and folding panels 104 have interior and exterior surfaces. The exterior surfaces of the panels 102 and 104 are those facing away from a user of the luggage when the luggage is in an open configuration. The interior surfaces of the panels 102 and 104 are those that face toward the user and contain various containers as described later in the specification.
[0015] In other embodiments of the luggage, top panel 102 may attach to edges 108 of folding panel 104 , and may enclose additional folding panels 104 between top panel 102 and the first folding panel 104 .
[0016] The panels 102 and 104 may be attached to each other using a variety of methods for forming folding joints known in the art of making luggage. For example, the panels may be foldably attached by zippers or hinges attached to the panels, or the panels may be sewn together to form a flexible joint. Alternatively, top panel 102 and foldable panels 104 are formed from one continuous sheet of flexible material. For example, panels 102 and 104 may be formed from a single sheet of cloth or fabric.
[0017] The folding panels 104 releaseably attach to each other along exterior edges 108 . The releaseable attachment along edges 108 may be one or a combination of various devices and materials for releaseable attachments, including, without limitation, zippers, Velcro, snaps, straps, latches, drawstrings or other similar means of closing luggage.
[0018] One or more handles for carrying the luggage may be attached to it in various locations. A handle may be located along the exterior edge 106 , on the side of the luggage opposite the containers. A handle may be attached to the edges 108 of one or both of the panels 102 and 104 , at any point and along any side of the luggage. The handle may consist of multiple pieces that are attached to several different panels 102 or 104 , and that are disposed adjacent to one another for use as a handle only when luggage 100 is in the closed configuration.
[0019] A folding hanger 110 is foldably attached to top panel 102 near edge 108 . The folding hanger 110 is adapted to hang over the bar provided in closets, or over hooks provided for hanging bags or articles of clothing. The folding hanger 110 may be formed from plastic, metal, wire, fabric, chain, or some combination thereof. The folding hanger 110 may be foldably attached to top panel 102 utilizing hinges, sewn attachment or other foldable means of connection. The hanger 110 may be folded down over top panel 102 in a folded configuration for carrying the luggage. An attachment may be provided for fastening the hook end of the hanger 110 to the top panel 102 to prevent shifting during carrying or travel, such as a strap secured by velcro or a snap.
[0020] A mirror 112 is provided for use when the hanging luggage is in the open configuration. In one embodiment of the hanging luggage 100 , the mirror 112 is attached to the folding hanger 110 . The mirror 112 may also be attached to the top panel 102 independently of the hanger 110 , so long as it is foldably attached to the top panel 102 for flat storage in the folded configuration of the hanging luggage 102 . The mirror 1 12 may optionally be lit by light fixtures incorporated into the luggage. The light fixtures may be powered by batteries incorporated into the luggage, or by an accessory cord to plug the luggage into an electrical wall outlet.
[0021] A shelf 114 may also be provided near edge 108 of top panel 102 adjacent to the folding hanger 110 . The shelf 114 may be used to temporarily store items otherwise stored in the compartments of the hanging luggage 100 during use when it is in the open position. Shelf 114 is formed from a rigid material capable of supporting items such as toiletries or cosmetics, including plastics, metals or flexible materials supported by a rigid frame. Shelf 114 is foldably connected to top panel 102 to allow it to fold flat against top panel 102 for storage in the folded configuration of the luggage 100 . Additional support for shelf 114 may be provided in the form of straps 115 attached to the outside edge of shelf 114 and to top panel 102 near edge 108 , or in support elements underneath shelf 114 and built into top panel 102 .
[0022] Containers 116 are arrayed on both top panel 102 and folding panels 104 . Containers 116 provide storage for items of various sizes and shapes. The containers 116 may be formed from mesh, fabric, plastics, or other similar materials suitable for forming flexible containers in luggage. Containers 116 may be formed by sewing a pocket of fabric into the inside lining of panels 102 and 104 . They may also be self-contained pouches that are attached to panels 102 and 104 by sewing, gussetts, or otherwise. Containers 116 may be open on top, may close with elastic cord, drawstrings, snaps, buttons, or zip shut, or may be secured shut in other ways commonly used to secure the opening of bags, pouches, pockets, and other such containers.
[0023] Certain containers 118 may be removable. Containers 118 are formed from the same types of materials and using the same methods of construction as described for containers 116 above. The removable containers 118 are releaseably attached to the top panel 102 and the folding panels 104 along the foldable attachment between the first and second folding panels 104 , and in other locations on the interior surface of the panels 102 and 104 . The removable containers 118 are releaseably attached to the panels 102 and 104 using ring binders or clips, straps, velcro, zippers, or combinations thereof. Different configurations of removable containers 118 may be formed by attaching varying sizes of removable containers 118 within the hanging luggage 100 .
[0024] A user of the luggage may remove some of the removable containers 118 , may purchase and add additional removable containers of different sizes or shapes than those originally provided by with the luggage, or may rearrange the removable inserts in the luggage by unclipping the containers and reclipping them in a more suitable configuration in the luggage. By reconfiguring the removable containers 118 , the luggage 100 may be customized for a specific use or for the tastes and convenience of the user.
[0025] The attachment member 122 provides the method of releasable attachment between removable containers 118 and luggage 100 . Luggage 100 may have multiple attachment members 122 located at various areas of luggage 100 , on panels 102 and 104 . In the embodiment of the luggage 100 shown in FIG. 1 , the attachment member is a ring clip device, providing releasable ring clips that may be opened or closed to remove or attach containers 118 as desired. Other embodiments of the luggage 100 may use other attachment members 122 , such as velcro strips, zippers, clips, straps or combinations thereof.
[0026] Referring now to FIG. 2 , hanging luggage 100 is shown in a partially folded configuration. Shelf 114 is folded up and is flat against top panel 102 . Folding hanger 110 is folded down over shelf 114 and is flat against top panel 102 . To further fold the luggage 100 for travel, top panel 102 would be folded down into first folding panel 104 , then the folding panels 104 would be folded together and releaseably attached along edges 108 .
[0027] In the folded configuration, luggage 100 may be carried by handles 120 . Handles 120 may be formed from flexible fabric straps, rigid plastic or metal, or some combination thereof. In other embodiments of the luggage 100 , removeably attached or integrated shoulder straps or integrated wheeled carriers may be provided. Such handles, straps or other means for carrying the luggage 100 may also be provided on the exterior surface of the luggage 100 at the foldable attachment between the folding panels 104 .
[0028] Referring now to FIG. 3 , an embodiment of the luggage 100 is shown in the open configuration. Sidewalls 109 are shown for defining the interior of luggage 100 and extending edges 108 for attachment to the opposing edges of panels 102 and 104 , as appropriate. A view of folding hanger 110 is shown in the open position. Containers 1 16 and removable containers 118 are shown, attached to the top and folding panels, 102 and 104 respectively. FIG. 3 also includes a view of the handle 120 .
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An article of luggage is described, incorporating a folding hanger, mirror and shelf, and a number of permanent and removably attached containers inside the luggage. The article of luggage may be hung in an open configuration for use of the items stored within. It may also be folded for storage or transport, in which folded configuration the hanger, mirror and shelf are folded and stored internally in the luggage. The removably attached containers may be rearranged within the luggage to provide a custom configuration.
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CROSS REFERENCE TO RELATED APPLICATIONS
Related subject matter can be found in the following copending applications, each of which is assigned to the assignee hereof:
1. Application Ser. No. 261,852, entitled "DIGITAL TO ANALOG CONVERTER", filed simultaneously herewith by Robert Noble Allgood and Stephen Harlow Kelley.
2. Application Ser. No. 261,850, entitled "A CAPACITIVE DAC TO SWITCHED CAPACITOR FILTER INTERFACE CIRCUIT", filed simultaneously herewith by Stephen Harlow Kelley and Richard Walter Ulmer.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to operational amplifier circuits and more particularly to an operational amplifier circuit that is selectively reconfigured as a filter, a sample and hold circuit, and a comparator.
2. Description of the Prior Art
Typically, operational amplifiers are used in a variety of circuits. One application of an operational amplifier is in a filter circuit whereby low frequency poles are effected by the use of external components. Operational amplifiers are also used to sample a signal onto a feedback capacitor and temporarily hold the signal. Such circuits are known as sample and hold circuits and are used to transfer the charge produced by the sampled signal to a capacitance storage device. Another typical application of an operational amplifier is in a comparator circuit in which the difference between two input signals is amplified. Comparators are utilized extensively in analog to digital and digital to analog conversion circuits.
Disadvantages in the prior art are evident when more than one of these operational amplifier circuits is desired in a single integrated circuit application. Typically, separate operational amplifiers are used for each circuit application. Apart from the large die areas that are required when multiple operational amplifiers are used, each operational amplifier adds its own offset error into the system, and offset compensation circuits increase the circuit's size. When two or more circuit functions have been combined, external components such as sample and hold capacitors and coupling capacitors have generally been required. As a result of the limited ability to use a single operational amplifier for multiple functions, the prior art tended to dedicate each operational amplifier to specific circuit functions.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an operational amplifier circuit which may be selectively reconfigured to provide several circuit functions.
Another object of the present invention is to provide a circuit having a single operational amplifier which selectively operates as a filter, a sample and hold circuit, a comparator and a circuit which can charge an output capacitance.
A further object of the present invention is to provide a multiple function operational amplifier circuit fabricated using switched capacitor techniques in a standard CMOS process.
According to a preferred form of the invention, there is provided an operational amplifier with an AC coupled input and a feedback capacitor which stores an input signal. Switched capacitance means may be selectively coupled between the output and the inverting input of the operational amplifier to simulate a load resistance and create a filter by effecting a frequency pole. The value of the switched capacitor determines, in part, the frequency range of the operational amplifier filter. After a charge has been stored on the feedback capacitor, switching means may be used to transfer the charge to an output capacitance such as a digital to analog converter (DAC). The charge on the output capacitance may be modified while making an A/D or a D/A conversion and then transferred to the input of the operational amplifier which now operates as a comparator to compare the transferred charge with a reference voltage. The inputs of the operational amplifier are selectively reversed to nullify the offset error. The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram illustrating one preferred embodiment of the invention.
FIG. 2 is a schematic diagram illustrating one preferred embodiment of the digital to analog converter.
FIG. 3 is a graphic timing diagram for the schematic embodiment shown in FIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Shown in FIG. 1, is a combined filter and coder/decoder (codec) circuit 10 constructed in accordance with the preferred embodiment of this invention. The filter-codec circuit 10 is comprised generally of a switched capacitor multiple function operational amplifier portion 12, a ladder switched capacitive digital to analog converter (DAC) portion 14, and a receive filter portion 16 which interfaces with the DAC portion 14. The circuit 10 is capable of receiving and storing an analog signal, V IN , while simultaneously filtering the signal. The signal V IN may be transferred to the DAC portion 14 and converted to a digital output by utilizing the operational amplifier portion 12 as a comparator. An analog to digital (A/D) conversion may be interrupted at any time and the DAC portion 14 discharged and utilized to perform a digital to analog (D/A) conversion. After a D/A conversion has been made, the A/D conversion may be resumed. Thus the circuit 10 is particularly useful for PCM voice encoding and decoding because the two functions may be asynchronous.
In the preferred form, operational amplifier portion 12 has an operational amplifier 18 with its non-inverting and inverting inputs connected to a reference voltage, say analog ground V AG , via switches 20 and 22, respectively. A first plate of feedback capacitor 24 is connected to the inverting input of the operational amplifier 18 via a switch 26 and a second plate of the capacitor 24 is connected to the output of the operational amplifier 18 via a switch 28. An input capacitor 32 provides AC coupling of an input signal V IN to the inverting input of the operational amplifier 18 via the switch 26 and the passband gain K of the operational amplifier portion 12 is approximately equal to the ratio of capacitors 32 and 24.
In the preferred embodiment, all the switches are conventional CMOS transmission gates which are constructed to be enabled or closed when a clock signal, applied to the control inputs thereof by a clock generator 30, is in a high state, and disabled or open when the clock signal is in a low state. Thus, for example, when the switch 20 is enabled by signal A, switches 26 and 28 are enabled by signal B, and switch 22 is disabled by signal C, the operational amplifier portion 12 is connected to sample the input signal V IN onto the feedback capacitor 24.
A switch 34 connects the first plate of feedback capacitor 24 to a first plate of a switched capacitor 36, and a switch 38 connects the second plate of the feedback capacitor 24 to the first plate of the switched capacitor 36. The second plate of the switched capacitor 36 is connected to the reference V AG . The switches 34 and 38 are controlled by signals E and D, respectively, and alternately switch the capacitor 36 from the inverting input to the output of the operational amplifier 18. The value of the capacitor 36 determines, in part, the location of a high pass pole of the operational amplifier portion 12 of the circuit 10, permitting the filtering of the input signal V IN while it is being sampled onto the feedback capacitor 24.
In the preferred embodiment, the DAC portion 14 has a first input terminal which is selectively coupled to a first reference voltage, ±V ref , via a switch 40; a second input terminal which is selectively coupled to the output of the operational amplifier portion 12 or a second reference voltage, V AG , via switches 42 and 43, respectively; and an output terminal selectively coupled to the second reference voltage, V AG , the non-inverting input of the operational amplifier 18 or the input of the receive filter portion 16 via switches 44, 45 and 46, respectively. In general, the DAC portion 14 can be represented as an unswitched capacitor 47 and a switched capacitor 48. In the illustrated form, the first plates of the capacitors 47 and 48 may be selectively coupled via a DAC switch 49 to form the effective first plate of the DAC portion 14, while the second plates thereof are coupled together to form the second plate of the DAC portion 14.
In operation, switches 40, 42, 43, 44, 45, 46 and 49 are controlled by signals H, F, F, G, C, I and H, respectively. For example, the input sample KV IN can be transferred onto the DAC portion 14 as it is being sampled onto the feedback capacitor 24, if, as shown in FIG. 3, the signals F and G are simultaneously in the high state and the signal H is in the low state. Thus, another function of the operational amplifier portion 12 is to charge the DAC portion 14 to the input sample KV IN preparatory to converting the analog input signal into a digital signal. If it may be necessary for the DAC portion 14 to be charged from the feedback capacitor 24 relatively long after a sample is placed thereon, switches 26 and 28 should be compensated switches to isolate the charged capacitor 24 and prevent parasitic leakage paths from leaking part of the sampled charge off of the feedback capacitor 24. In addition, it should be recognized that the offset voltage of the operational amplifier 18 will be charged onto the DAC portion 14 along with the input signal sample.
When the switch 22 is enabled by signal C, the operational amplifier 18 may be reconfigured as a comparator for use in an A/D conversion. For example, if switches 43 and 45 are enabled via signals F and C, respectively, while switches 42 and 44 are disabled via signals F and G, respectively, then the voltage transferred onto DAC portion 14 by the operational amplifier portion 12 will be translated relative to the second reference voltage V AG . Of course, the stored offset voltage will also be translated by the switching action, but will now appear as an error of opposite polarity. By switching the inverting input of the operational amplifier 18 from the feedback capacitor 24 to the second reference voltage V AG and the non-inverting input from the second reference V AG to the output terminal of the DAC portion 14, the operational amplifier 18 will be connected as a comparator and will provide an output indicative of the difference between the voltages on the inputs thereof. Note that the offset voltage stored on the DAC portion 14 is now present as a bias on the non-inverting input of the operational amplifier so that the offset voltage of the operational amplifier 18 will be automatically cancelled.
If, before an A/D conversion has been completed, it is desired to perform a D/A conversion, the DAC portion 14 can be discharged and used to perform the D/A conversion. For example, switches 42 and 44 may be enabled by signals F and G, respectively, to discharge the DAC 14. Thereafter, switches 40 and 49 may be enabled by signals H and H, respectively, to charge the DAC portion 14 to a percentage of the first reference ±V ref representing the analog equivalent of a digital input which is being converted. After the D/A conversion is completed, the input sample KV IN may again be charged onto the DAC portion 14 as previously detailed and the A/D conversion restarted where it was interrupted.
In the illustrated embodiment, one operational amplifier 18 has been used for a variety of circuit functions. In the preferred embodiment, the operational amplifier portion 12 may be conveniently fabricated as a monolithic integrated circuit which requires no external components to perfrom each of the described circuit functions.
Shown in FIG. 2 is a preferred form of the DAC portion 14 of FIG. 1. In the illustrated form, the DAC portion 14 is comprised of two DAC sections, a capacitive or C DAC section 50 and a resistive or R DAC section 52. DACs of this form are commonly called stacked DACS and find frequent application in pulse code modulation (PCM) to make use of companding (compression/expansion) which permits an 8-bit binary code to cover a greater dynamic range than otherwise possible. Two internationally known companded codes are the Mu-255 compression law and the segmented A-law. In both laws, samples of an analog speech signal are mapped using an 8-bit PCM code into sixteen chords, with each chord comprising sixteen equal steps. In the Mu-255 law, the step intervals in each chord precisely double in size away from the origin of the input-output curve. The same is also true for the A-law, except that the first two chords on each side of the origin have the same step size. Both laws contain 256 quantization levels which are bounded by 255 decision levels. The format of the 8-bit companded PCM word is for the first bit to indicate the sign of the voice signal, the second through fourth bits are chord bits which, with the sign bit, indicate which one of the sixteen chords the signal is in, and the fifth through eighth bits are step bits which indicate which one of the sixteen steps the signal corresponds to.
In the illustrated embodiment, the C DAC section 50 includes a unit capacitor 54 and eight rank ordered capacitors 56 through 70 which are effectively binarily weighted by the ratio 2 n , where n equals 0-7 for capacitors 56-70, respectively. The capacitors 54-70 each have a first and second plate, with the second plates being coupled to the output terminal of the DAC portion 14.
In the illustrated embodiment, a dividing capacitor 72 is interposed between the second plates of capacitors 54-62 and the second plates of capacitors 64-70, to reduce the physical size of the capacitors 64-70 relative to capacitors 54-62 and eliminate problems associated with large ratios which tend to be imprecise. Stated another way, the dividing capacitor 72 is used to divide the effective value of the capacitors 54-62 as seen by the capacitors 64-70. Thus, although the weighted value of each capacitor is as shown in FIG. 2, the actual unit values of the capacitors 54-70 are, in the preferred form, respectively 1, 1, 2, 4, 8, 1, 2, 4 and 8. However, the capacitors 54-62 contribute a total unit value of only 1 at the output due to the dividing capacitor 72, while the capacitors 64-70 contribute a total unit value of 15 units at the output. It should be noted that the embodiment shown is only exemplary and other values may be substituted. In order to make the impedance of the capacitors 54-62 in series with capacitor 72 equal to 1 unit at the output terminal of the DAC portion 14 and allow the capacitors 5-62 to have unit weights totaling 16, the weighted value of the capacitor 72 is found by solving the following for X, the weighted value:
1/16+1/X=1 or, X=16/15=1.067 unit The capacitive DAC section 50 also includes a C ladder switching network 74 for selectively coupling the first plates of the capacitors 54-70 to the first reference voltage ±V ref , the second reference voltage V AG , or a step voltage developed by the R DAC section 52 on a common rail 76. In the preferred form, the C ladder switching network 74 comprises C rail switches 78 through 94, with the switch 78 being connected between the first reference voltage ±V ref and the first plate of the capacitor 54, and the switch 94 being connected between the second reference voltage V AG and the first plate of the capacitor 68. The switches 80 through 92 are connected between the first plates of respective, successively ordered pairs of the capacitors 56-70. The C ladder switching network 74 further includes C rung switches 96-110, coupled between the first plates of the capacitors 56-70, respectively, and the common rail 76. Each of the C rail switches 78-94 and the C rung switches 96-110 has a rank order corresponding to the rank of the associated capacitors 56-70.
The C ladder switching network 74 is controlled by a C logic circuit which includes a one-of-eight, C decoder 111 having digital inputs b1, b2, and b3 which receive corresponding chord input code bits of the PCM word, and eight rank ordered C rung outputs, each of which provides a C rung enable signal to a respective one of the ranked C rung switches 96-110. For example, the C rung output corresponding to a chord input code of 000 is connected to the C rung switch 96. Thus, for any one particular chord input code, a respective one of the C rung enable signals will be provided to enable the associated one of the C rung switches 96-110, and all the other C rung switches 96-110 will be disabled.
The C logic circuit also includes rank ordered gates 112 through 128 which provide C rail disable signals to selectively disable respective C rail switches 78-94. In the illustrated form, the gates 114-126 are two-input NOR gates which have the inputs thereof coupled to respective adjacent pairs of the C rung outputs beginning from the lowest rank (chord input codes 000 and 001) to the highest rank (chord input codes 110 and 111). Gate 112 is a three-input NOR which has a first input thereof coupled to the lowest ranked C rung output (chord input code 000), a second input thereof coupled to a Charge DAC or CD disable signal for selectively decoupling the first plates of the capacitors 54-70 from the first and second reference voltages, and a third input thereof coupled to a D/A Discharge or DAD disable signal for selectively discharging the DAC capacitors 54-70 in preparation for a digital to analog conversion. The gate 128 is a two-input NAND having a first input thereof coupled to the inverse of the DAD disable signal and the second input thereof coupled to the output of a gate 130. The gate 130 is preferably a two-input OR having a first input thereof coupled to the highest ordered C rung output (chord input code 111) and a second input thereof coupled to the CD disable signal.
In this configuration, the C rail disable outputs from the gates 112-128 determine which of the first plates of the capacitors 56-70 are connected to one another and to the reference voltages ±V ref and V AG . Assuming that the CD disable signal is in a high state, the gate 112 disables the C rail switch 78 to decouple the first plates of the capacitors 56-70 from the first reference voltage, ±V ref , and the gates 128 and 130 cooperate to disable the C rail switch 94 to decouple the first plates of the capacitors 56-70 from the second reference voltage V AG . If, as shown in FIG. 3, the CD disable signal is also coupled to the control input of the switch 42 as signal F, switch 42 will then couple the input signal sample onto the first plates of the capacitors 56-70. On the other hand if the DAD disable signal is in the high state, the gate 112 disables C rail switch 78 to decouple the first plates of the capacitors 56-70 from the first reference voltage ±V ref , and gate 128 enables C rail switch 94 to couple the first plates of the capacitors 56-70 to the second reference voltage V AG .
In the illustrated embodiment, the C decoder 111 may be selectively disabled via a Mux disable signal whenever it is necessary to charge or discharge the capacitors 54-70. In the preferred embodiment, the C decoder 111 will respond to a Mux disable signal in the high state by providing an enable signal on the lowest C rung output only. Simultaneously, an inverter 132 disables a gate 134 interposed in the lowest C rung output between the gates 112 and 114 and switch 96, and the C decoder 111, to prevent the enable signal from otherwise enabling the C rung switch 96. Preferably, the gate 134 is a two-input AND having a first input connected to the lowest ranked C rung output and a second input connected to the output of the inverter 132, the input of the latter being coupled to receive the Mux disable signal.
In the illustrated embodiment, the R DAC section 52 includes a voltage divider for developing on each of a rank ordered plurality of step nodes a step voltage between the first reference voltage ±V ref and the second reference voltage V AG . In the preferred form, the voltage divider comprises a plurality of resistors 136 through 170 connected in series between the first reference voltage ±V ref and the second reference voltage V AG , with the resistors 136, 168 and 170 having a relative value of one unit each and the resistors 138 through 166 having a relative value of two units each. In this configuration, predetermined step voltages having absolute values spaced between ±V ref and V AG are developed on the step nodes between each pair of resistors 136-170.
The R DAC section 52 also includes an R ladder switching network for coupling a selected one of the step nodes to the common rail 76. In particular, a plurality of rank ordered R rung switches 172 through 202 couple respective step nodes to the common rail 76. In the preferred form, switches 204 and 206 are coupled in parallel with resistors 136 and 170, respectively, to selectively short one of the resistors 136 and 170 in response to an Encode/Decode or En/Dec signal for reasons made clear hereinafter.
The R ladder switching network is controlled by a one-of-sixteen, R decoder 210 having digital inputs b4, b5, b6 and b7 corresponding to the step input code bits of the PCM word, and sixteen R rung outputs for providing enable signals to respective R rung switches 172 through 202. For example, the R rung output corresponding to a step input code of 0000 is connected to the R rung switch 172, and the R rung output corresponding to a step input code of 1111 is connected to the R rung switch 202. Thus for any one particular step input code, a respective one of the R rung enable signals will be provided to enable the associated one of the R rung switches 172-202. In response to the R rung enable signal, the particular R rung switch 172-202 will couple a respective step node to the common rail 76. Thus, each step voltage developed across the R DAC section 52 may be selectively connected to the C DAC section 50 via the common rail 76.
To obtain a programmable A- an MU-255 law capability, the DAC portion 14 utilizes the coding capacitor 54 which has a first plate connected to a first code switch 214. The first code switch 214 couples the first plate of the coding capacitor 54 to the first plate of the lowest ranked capacitor 56. A second plate of the coding capacitor 54 is connected to the second plate of the capacitor 56. A second code switch 215 is connected between the second reference voltage V AG and the first plate of the coding capacitor 54. The first code switch 214 is enabled when either an A-law PCM conversion signal or a CD enable signal is applied to its control input terminal in a high state. The second code switch 215 is enabled whenever both a Mu-law PCM conversion signal and the complement of the CD enable signal are applied in a high state to its control input terminal. Whenever the first code switch 214 is enabled, the second code switch 215 is disabled and the DAC portion 48 provides A-law PCM conversion. Thus, the coding capacitor 54 is always connected in parallel with the capacitor 56 when the C DAC section 50 is being charged. When A-law conversion is desired, the capacitor 54 is allowed to remain in parallel with the capacitor 56, so that the combination of the capacitors 54 and 56 provides a capacitance of two units. However, when Mu-255 law conversion is desired, the first plate of the coding capacitor 54 is connected to the second reference voltage V AG and disconnected from the first plate of the capacitor 56. This removes one unit of capacitance from the C DAC section 50 to provide one-half the A-law chord size in chord 000. Thus, the step size at the origin is one-half as large in Mu-law as the step size at the origin in A-law.
Since the polarity of the input sample KV IN may be above or below the second reference voltage V AG , the DAC portion 14 must be able to compare the sample on the C DAC 50 to both the positive and the negative forms of the first reference voltage ±V ref . In the preferred embodiment, reference voltage generators (not shown) generate the required first reference voltages ±V ref and -V ref . As shown in FIG. 2, the appropriate one of the positive and negative first reference voltages may be selectively coupled to the C DAC 50 and R DAC 52 via switches 216 and 217, respectively, as described hereinafter.
Referring again to FIG. 1, the first stage of the receive filter portion 16 comprises an operational amplifier 220, a feedback capacitor 218, and a switched capacitor 222 having a first plate connected to the reference V AG and a second plate which is alternately connected to the non-inverting input of the operational amplifier 220, via a switch 224, and the output of the operational amplifier 220, via a switch 226, in response to a control signal J and the inverse thereof, to simulate a feedback resistance. In the preferred embodiment, the receive filter portion 16 includes additional filter stages with appropriate feedback paths (not shown) for performing the desired filter functions. By selectively coupling the charge of the DAC portion 14 directly to the input of the receive filter 16 via switch 46, the need for an intermediate buffer amplifier is totally eliminated. In this configuration, parasitic capacitance errors normally associated with the use of a buffer amplifier to couple the output of the DAC portion 14 to the receive filter portion 16 are eliminated since the output terminal of the DAC portion 14 will always settle to the second reference voltage V AG . The elimination of the buffer amplifier also conserves power and circuit area.
The international standard sampling rate for PCM voice encoding is 8 kHz or one frame every 125 usec. In the preferred embodiment, each frame is divided into sixteen equal conversion segments, and is synchronized to a Tx Sync signal. To illustrate the cooperation of the operational amplifier portion 12 and the DAC portion 14, reference will now be made to FIG. 3 which illustrates one frame in which two D/A conversions are asynchronously performed in the course of one A/D conversion. Of course, the example shown in FIG. 3 is representative of only one of many ways the circuit 10 is capable of performing.
In general, an A/D conversion is performed by sampling the analog input signal V IN , and storing an input sample -KV IN onto the feedback capacitor 24. The input sample is then transferred onto the first plates of the capacitors 54-70 of the DAC portion 14, and translated onto the second plates thereof to reinvert the sample. The polarity of the translated sample is then determined relative to the second reference voltage V AG . A binary search is then performed, using a conventional successive approximation register or SAR (not shown), to converge to the digital code which, when converted using the DAC portion 14, will effectively cancel the sample charge on the second plates of the capacitors 54-70, and force the voltage on the output terminal of the DAC portion 14 to the second reference voltage V AG . Recall that when the DAC portion 14 is being charged to the input sample voltage, the switch 214 is enabled and the switch 215 is disabled, adding the one unit of capacitance of the capacitor 54 to the 255 units of capacitance of the capacitors 56-70 for a total C DAC 50 capacitance of 256 units. Since the R DAC 52 is capable of applying any one of the sixteen step voltages to any one of the capacitors 54-70 via the step node 76, the DAC portion 14 effectively divides the voltage difference between the first reference voltage ±V ref and the second reference voltage V AG into 256(units of capacitance)x16(step voltages) or 4096 segments. However, the DAC portion 14 is actually able to generate only 8(chords)x16(steps) or 128 of these segments, due to the increasing step and chord size inherent in companding.
In the process of encoding, the analog input sample is compared against a set of decision levels corresponding to the segments the DAC portion 14 can generate with the R DAC 52 configured to provide step voltages which are multiples of the first reference voltage V ref /16. In the preferred embodiment, the R DAC 52 is so configured by the En/Dec signal, which enables switch 204 and disables switch 206. However, it is well known that this technique of encoding results in a quantizing error in the range of 0 to -1.
In the example shown in FIG. 3, it will be assumed that the DAC portion 14 is operating according to the Mu-255 companding law. In this mode, the first plate of capacitor 54 is coupled via switch 215 to the second reference voltage V AG during the conversion, so that only 255 units of capacitance can be switched to each of the 16 step voltages for a total of only 4080 segments. Thus, the effective range of the DAC portion 14 is limited to (4080/4096x±V ref .
During the first segment, the analog input signal V IN is sampled, and the instantaneous value stored on the feedback capacitor 24 is -KV IN , where -K is the gain of the operational amplifier 18. For the purposes of this explanation, it will be assumed that the input sample -KV IN , stored on the feedback capacitor 24, has a value of -340/4096 of the first reference voltage +V ref . Simultaneously, the input sample is transferred to the first plates of the capacitors 54-70 of the C DAC circuit 50 via the gate 42 which is enabled by the signal CD. After the input sample has been stored on the C DAC 50, the sample is translated relative to the second reference voltage V AG by coupling the second plates of capacitors 54-70 to the non-inverting input of operational amplifier 18 and the first plates of capacitors 54-70 to the second reference voltage V AG . The polarity of the sample can now be determined by configuring the operational amplifier 18 as a comparator to compare the translated sample to the second reference voltage V AG . For the example given, the output of the operational amplifier 18 will be positive, indicating that the input sample KV IN was positive when sampled. The result of the comparison is then stored as a positive sign bit in the SAR, and used to select the negative one of the first reference voltages ±V ref by disabling switch 216 and enabling switch 217.
During the second segment, the SAR forces the next most significant bit or b1 to a 1, making a mid-range chord input code 100 to the C decoder 111 and the low-range step input code 0000 to the R decoder 210. In response to the chord input code of 100, the C decoder 111 and gates 112-130 disable switches 86 and 88, and enable switches 78-84 and 90-94, to couple the first plates of capacitors 56-62 to the first reference voltage -V ref and the first plates of capacitors 66-70 to the second reference voltage V AG . The C decoder 111 and gates 112-130 also disable switches 96-102 and 106-110, and enable switch 104 to couple the first plate of capacitor 64 to the step node 76. In response to the step input code of 0000, the R decoder 210 disables switches 174-202 and enables switch 172, to couple the step node 76 to the second reference voltage V AG . The resulting sharing on the second plates of the capacitors 54-70 of the charge representing the stored sample, develops a voltage on the second plates of the capacitors 54-70, and the voltage is applied to the non-inverting input of the operational amplifier 18, which is still in the comparator configuration.
Since the charge due to the switching of the first plates of capacitors 56-62 to the first reference voltage -V ref is not sufficient to cancel all of the sample charge on the second plates of all of the capacitors 54-70, the voltage on the second plates will still be above the second reference voltage V AG . The output of the operational amplifier 18 will therefore be positive, resulting in a code of 1 being stored in the b1 position of the SAR.
In the hypothetical example shown, an Rx Sync signal is received during the third segment, indicating that the A/D conversion sequence must be interrupted to perform a D/A conversion. Thus, during the fourth segment, the DAC capacitors 54-70 are initially discharged, since the input sample -KV IN is still being held on the feedback capacitor 24. Assume, for example, that a digital input code 00101100 has been received. Since the sign bit b0 is 0, the desired analog output signal must be negative. If the receive filter portion 16 has an odd number of inversion stages therein, as in the preferred embodiment, then the positive one of the first reference voltages +V ref must be selected by enabling switch 216 and disabling switch 217. After discharge, the C decoder 111 responds to the chord input code of 010 by enabling switches 78-80, 86-94 and 100, and disabling switches 82 and 84. Simultaneously, the R decoder 210 responds to the step input code of 1100 by enabling switch 196 and disabling 172-194 and 198-202. Thus, the first plates of capacitors 56 and 58 are coupled to the first reference voltage + V ref , the first plate of capacitor 60 is coupled to the step node 76, and the first plates of capacitors 62-70 and 54 are coupled to the second reference voltage V AG . For the example given, the step voltage developed by the R DAC 52 on step node 76 will be (25/32)xV ref . The charge on the output terminal of the DAC portion 14 resulting from the selective switching of the first plates of the capacitors 56-60 is coupled to the receive filter portion 16 via switch 46 under control of control signal I. It can be shown, using charge redistribution principles, that this charge is proportional to [(98/4096)x(+V ref )], with the proportionality constant being related to the Thevinin equivalent total capacitance of the array of capacitors 54-70 as seen from the output terminal of the DAC portion 14.
In the preferred embodiment, the capacitors 54-70 function as the input capacitance of the first stage of the receive filter portion 16, and determine in part the gain of this stage. In order to reduce the gain required of the first stage of the receive filter portion 16 while increasing the dynamic range of the filter portion 16, the D/A conversion is performed twice in consecutive segments in order to couple a sufficient amount of charge into the receive filter portion 16. An unexpected advantage accruing from interfacing the DAC portion 14 to the receive filter portion 16 in this manner is the automatic correction of the (sin x)/x distortion normally associated with flat-top or zero order hold sampling of an analog signal. For a more detailed description of this problem, reference may be made to U.S. Pat. No. 4,320,519, filed Apr. 10, 1980 by Stephen H. Kelley and Henry Wurzburg and assigned to the assignee of the present invention.
It is possible to minimize the quantizing error resulting from the original A/D conversion, by performing a half bit correction during the D/A conversion. To accomplish the correction, the R DAC 52 should be configured to provide the step voltages as odd multiples of the second reference voltage V AG /32. In the preferred embodiment, the R DAC 52 is so configured by the En/Dec signal which enables switch 206 and disables switch 204. The correction effectively raises or upshifts the R ladder by one-half LSB in a digital to analog conversion, to compensate for the relative lowering or downshifting of the R ladder by one-half LSB in an analog to digital conversion, resulting in a shifting of the quantizing error to the range of ±l/2.
By the end of the fifth segment, the converted analog signal has been coupled into the receive filter 16 and charged onto the filter feedback capacitor 218. At the start of the sixth period, the analog to digital conversion is resumed where it was interrupted, by charging the input sample -KV IN back onto the DAC capacitors 54-70 from the feedback capacitor 24. At the end of the sixth segment, the input signal sample is again translated onto the second plates of capacitors 54-70, as described above.
During the seventh segment, the SAR, which has remained at the value established by the end of the second segment, forces the next most significant digital input bit b2, i.e. the second chord input bit, to a 1. In response to the resulting chord input code of 110, the C decoder 111 and gates 112-130 disable switches 90 and 92, and enable switches 78-88 and 94, to couple the first plates of capacitors 56-66 to the first reference voltage -V ref and the first plate of capacitor 70 to the second reference voltage V AG . The C decoder 111 and gates 112-130 also disable switches 96-106 and 110, and enable switch 108, to couple the first plate of capacitor 68 to the step node 76. In response to the step input code of 0000, the R decoder 210 disables switches 174-202 and enables switch 172 and 204, to couple the step node 76 to the second reference voltage V AG . The resulting sharing on the second plates of the capacitors 54-70 of the charge representing the stored sample, develops a voltage on the second plates of the capacitors 54-70, which is applied to the non-inverting input of the operational amplifier 18, the latter being still in the comparator configuration.
Since the charge due to the switching of the first plates of capacitors 56-66 to the first reference voltage -V ref is now more than sufficient to cancel all of the sample charge on the second plates of all of the capacitors 54-70, the voltage on the second plates will be below the second reference voltage V AG . The output of the operational amplifier 18 will therefore be negative, resulting in a code of 0 being stored in the b2 position of the SAR.
During the eighth segment, the SAR forces the next most significant digital input bit b3, i.e. the third chord input bit, to a 1. In response to the resulting chord input code of 101, the C decoder 111 and gates 112-130 disable switches 88 and 90, and enable switches 78-86 and 92-94, to couple the first plates of capacitors 56-64 to the first reference voltage -V ref and the first plate of capacitors 68-70 to the second reference voltage V AG . The C decoder 111 and gates 112-130 also disable switches 96-104 and 108-110, and enable switch 106, to couple the first plate of capacitor 66 to the step node 76. In response to the step input code of 0000, the R decoder 210 disables switches 174-202 and enables switch 172 and 204, to couple the step node 76 to the second reference voltage V AG . The resulting sharing on the second plates of the capacitors 54-70 of the charge representing the stored sample, develops a voltage on the second plates of the capacitors 54-70, which is applied to the non-inverting input of the operational amplifier 18, the latter being still in the comparator configuration.
Since the charge due to the switching of the first plates of capacitors 56-64 to the first reference voltage -V ref is still more than sufficient to cancel all of the sample charge on the second plates of all of the capacitors 54-70, the voltage on the second plates will again be below the second reference voltage V AG . The output of the operational amplifier 18 will therefore be negative, resulting in a code of 0 being stored in the b3 position of the SAR. Thus, by the end of the eighth segment, the chord input portion of the SAR contains 100, indicating that the amplitude of the input signal sample is within chord 4.
During the ninth segment, the SAR forces the next most significant digital input bit b4, i.e the first step input bit, to a 1. In response to the chord input code of 100, the C decoder 111 and gates 112-130 disable switches 86-88, and enable switches 78-84 and 90-94, to couple the first plates of capacitors 56-62 to the first reference voltage -V ref and the first plate of capacitors 66-70 to the second reference voltage V AG . The C decoder 111 and gates 112-130 also disable switches 96-102 and 106-110, and enable switch 104, to couple the first plate of capacitor 64 to the step node 76. In response to the step input code of 1000, the R decoder 210 disables switches 172-186 and 190-202, and enables switch 188, to couple (16/32)xV ref to the first plate of capacitor 64 via step node 76. The resulting sharing on the second plates of the capacitors 54-70 of the charge representing the stored sample, develops a voltage on the second plates of the capacitors 54-70, which is applied to the non-inverting input of the operational amplifier 18, the latter being still in the comparator configuration.
Since the charge due to the switching of the first plates of capacitors 56-62 to the first reference voltage -V ref and the first plate of the capacitor 64 to (16/32)XV ref is still more than sufficient to cancel all of the sample charge on the second plates of all of the capacitors 54-70, the voltage on the second plates will again be below the second reference voltage V AG . The output of the operational amplifier 18 will therefore be negative, resulting in a code of 0 being stored in the b4 position of the SAR. In a similar manner, each of the remaining digital input bits b5, b6 and b7, corresponding to the remaining step input bits are determined in the tenth, eleventh and twelfth segments, respectively. Thus, by the end of the twelfth segment, the chord input portion of the SAR contains 100 and the step input portion of the SAR contains 0110, indicating that the amplitude of the input signal V IN , when sampled, was within step 6 of chord 4.
Any time after the A/D conversion has been completed, the contents of the SAR can be transferred into an appropriate holding register (not shown) for subsequent use or transmission. In the preferred embodiment, the transfer is accomplished during the segment following determination of digital code bit b7. The SAR is then cleared to all zeros so as to be ready for the next A/D conversion cycle.
During the thirteenth segment, a second Rx Sync signal is received. In response, the circuit 10 operates as described above to perform the requested digital to analog conversion during the fourteenth and fifteenth segments. When neither an analog to digital or a digital to analog conversion is occurring, the circuit may enter an idle mode, as in the thirteenth and sixteenth segments. Depending upon the relative timing of the Tx and Rx Sync signals, each frame may have from 0 to 4 idle mode segments.
Although the operation of the circuit 10 has been illustrated using the exemplary timing diagram of FIG. 3, it will be clear that the ability of the circuit 10 to perform two D/A conversions and one A/D conversion during a single frame assures asynchronous operation in voice applications. In fact, it can be shown that the circuit 10 will perform satisfactorily even if the Tx Sync signal occurs a few segments early, provided that the previous A/D conversion has been completed.
While the invention has been described in the context of a preferred embodiment, it will be apparent to those skilled in the art that the present invention may be modified in numerous ways and may assume many embodiments other than that specifically set out and described above. Accordingly, it is intended by the appended claims to cover all modifications of the invention which fall within the true spirit and scope of the invention.
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An operational amplifier capable of selectively performing a variety of circuit functions is provided. A single operational amplifier utilizes switched capacitors for sampling and holding an input signal, for establishing a low frequency pole, for applying the sample to an output capacitance to charge the capacitance and for comparing the input signal with a reference. The multi-function circuit provides a large savings in circuit area and permits versatility of circuit applications. One embodiment of the invention is to utilize a companding DAC having a capacitor array which may be used as the output capacitance of the operational amplifier circuit. The DAC provided utilizes an R ladder DAC coupled directly to a C DAC and has a switching structure that is simpler than comparable prior art circuits. The DAC is asynchronous and has programmable A-and Mu-255 law PCM conversion capability. Coupled directly to the C DAC is an operational amplifier receive filter circuit which utilizes the C DAC as an input capacitor thereby eliminating the need for a buffer amplifier and allowing the DAC to be used for both analog to digital and digital to analog conversion.
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FIELD OF THE INVENTION
The present invention relates to a method of manufacturing chemical pulp out of comminuted cellulosic fiber material, comprising digesting the fiber material with digestion liquid, said method excluding any peroxide stage before said digesting. The invention relates particularly to a method of the kind described, that gives improved properties with respect primarily to tearing resistance, viscosity and yield.
The object of the invention is to produce a chemical pulp which, already after the digestion process, has considerably reduced content of transition metals and at the same time considerably improved properties with regard especially but not exclusively to tearing resistance, viscosity, yield, kappa number and brightness.
BACKGROUND AND SUMMARY OF THE INVENTION
The method according to the invention is substantially characterised in that the comminuted fiber material is treated in at least one stage prior to said digestion, in the presence of a liquid containing at least one compound having the ability to form complexes together with metals existing naturally in the fiber material. Thus, the treatment with sequestering agent is carried out immediately prior to a pre-impregnation of the chips, for instance, or alternatively during, i.e. simultaneously with the pre-impregnation usually performed before digestion. Treatment with the sequestering agent added is performed so that a pulp is obtained after said digestion process which pulp, besides having a lower content of metals, primarily manganese, has a tearing resistance at least 10% higher, a viscosity at least 5% higher, and produces a yield at least 1% higher than corresponding parameters for a pulp manufactured without said pre-treatment with sequestering agent, calculated within the same kappa number interval.
The invention is applicable to any method whatsoever for manufacturing chemical pulp. A chemical pulp is defined as a pulp having a kappa number below about 100. Such pulps include sulphite and bisulphite pulps based on sodium, potassium or magnesium, alkaline neutral sulphite pulp, pulps of anthraquinone plus hydroxide (NaOH/KOH) or carbonate (Na 2 CO 3 /K 2 CO 3 ) plus possibly oxygen gas, polysulphide pulp, sulphate pulp and pulp produced by pre-impregnating wood with hydrogen sulphide before alkaline delignification, and also pulps produced by delignification of wood with organic solvent such as methanol, ethanol, possibly in the presence of inorganic solvent.
The compound able to form complexes with metals in the fiber material is suitably selected from the group consisting of non-nitrogenous polycarboxylic acids, nitrogenous polycarboxylic acids and phosphonic acids. Diethylene triamine pentacetic acid (DTPA), ethylene diamine tetracetic acid (EDTA) or nitrilo triacetic acid (NTA) are preferred from the first category, oxalic, citric or tartaric acid from the second category, and diethylene triamine pentaphosphoric acid from the third category. Most preferred are EDTA and DTPA. Two or more of the compounds may also be used, and in any combination whatsoever.
The treatment with sequestering agent is suitably performed at a pH value above about 5.0 and at a liquid/fiber material ratio greater than 2:1, preferably greater than 3:1. According to a suitable embodiment said treatment is performed at a temperature of at least 80° C., preferably at least 100° C., a pressure of at least 2 bar, preferably at least 5 bar, most preferably at least 10 bar, and over a period of at least 20 minutes, preferably at least 40 minutes, most preferably at least 60 minutes.
The sequestering agent is supplied in a quantity suitably within the interval 0.5-10 kg per ton of dry fiber material, preferably 1.5-5 kg and most preferably 2-4 kg per ton of dry fiber material.
A separate treatment vessel may be used for the treatment of the wood with sequestering agent, said vessel being located before, i.e. upstream of the digester tank. The treatment according to the invention may be included with the digestion in a continuous process or a discontinuous process for pulp production. The invention is applicable to all types of continuous and discontinuous digestion methods for the manufacture of chemical pulp.
According to one embodiment of the invention at least a considerable portion of free liquid containing metal complexes formed by said treatment is removed from the wood upon completion of the treatment with sequestering agent. This can be achieved by draining, i.e. thickening, and subsequent washing of the wood with a liquid free from metals or having low metal content. The liquid containing metal complexes is preferably removed by being displaced by cleaner liquid of the type described. The liquid removed is transferred directly to an evaporation system. Alternatively the formed metal complexes are permitted to accompany the fiber material into the digestion process.
At least a part of said liquid present during treatment of the fiber material and containing the sequestering agent, consists of spent liquor, fresh digestion liquid, effluent from bleaching processes, condensation, mains water or lake water, or mixtures thereof. The spent liquor used is suitably the spent liquor having reduced, low content of metals that is obtained at said digestion following said treatment with sequestering agent.
Generally the digestion process includes a pre-impregnation of the wood with digestion liquid and/or spent liquor and according to one embodiment of the invention, the treatment with sequestering agent is performed prior to said pre-impregnation and is followed by a washing stage of suitable type as described above. According to another embodiment the treatment with sequestering agent is performed in combination with the actual pre-impregnation as an integrated treatment, in which case the sequestering agent is preferably added together with the impregnation liquid. In this case the metal complexes formed, together with any excess of sequestering agent remaining, accompany the wood to the digestion zone(s) and are not therefore removed before digestion, but at a later stage when the spent liquor is withdrawn. In certain cases the impregnation phase may be relatively short, such as down to about 1 minute, during which brief period treatment with sequestering agent is performed before the digestion phase is started in the continuous process.
Said spent liquor may be black liquor received from the digestion of wood that has been treated with sequestering agent in accordance with one of the alternatives described above. The cooking liquid may be fresh white liquor.
The treatment with sequestering agent may be most advantageously performed in conjunction with an isothermal cooking process that includes a final extended displacement step in which the operating conditions correspond, or substantially correspond, to those prevailing in the preceding digestion zone(s).
The pulp is delignified with oxygen gas after the digestion process. The pulp is suitably treated with sequestering agent immediately prior to the delignification with oxygen gas. The pulp delignified with oxygen gas may then suitably be bleached with a bleaching agent containing hydrogen peroxide, possibly in combination with ozone and/or peracetic acid.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is further explained in the following examples, which are not however intended to limit the application and scope of the invention, and with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating the alkali consumption as a function of the kappa number.
FIG. 2 is a diagram illustrating the brightness as a function of the kappa number.
FIG. 3 is a diagram illustrating the yield as a function of the kappa number.
FIG. 4 is a diagram illustrating the viscosity as a function of the kappa number.
DETAILED DESCRIPTION OF THE INVENTION
In the diagrams shown in the drawings the numbers 1-9 indicate the plotted values from the experiments with the same numbering that are described in the following examples, i.e. the number 1 in the diagram according to FIG. 1 indicates the yield and kappa number values from Experiment 1. The four different symbols are explained in FIG. 1. ITC stands for isothermal cooking which is explained further below.
EXAMPLE
Test 1
Moist chips equivalent to 2.5 kg absolutely dry chips of Scandinavian softwood were treated with steam in a digester with circulation for 5 min. at 110° C. and a pressure of 1.0 bar. The chips contained 220 ppm manganese calculated on the digested pulp at a yield of 45%.
In accordance with the present invention the steamed chips were treated with a sequestering agent dissolved in a liquid. The liquid used was de-ionized water and the sequestering agent used was EDTA in a quantity of 0.005 kg, corresponding to 2.0 kg EDTA per ton of wood. The liquid/wood ratio was 5.5:1. The pH value of the liquid containing EDTA was 6.7. The treatment with EDTA was performed in a digester with circulation for 60 min. at 110° C. and a pressure of 10 bar, the liquid being circulated the whole time. Free liquid was then emptied from the digester in an amount corresponding to 65% of the total content of free and bound liquid. Hot, de-ionized water (without EDTA) was added and allowed to circulate through the digester under steam pressure for 60 min. at a temperature of 110° C. Free liquid is then again emptied from the digester in an amount corresponding to 65% of the total content of liquid.
The chips pre-treated in this way were then subjected to a digestion process of the isothermal cooking type (ITC), preceded by impregnation with digestion liquid in the form of white liquor. The digestion process comprised concurrent digestion, countercurrent digestion displacing black liquor with white liquor, and then an extended displacement phase with white liquor corresponding to the conditions in a "Hi-heat" zone. The white liquor had a sulphidity of 33.2%. At the starting impregnation 140 kg white liquor was used, calculated as effective alkali (EA) per ton of wood. The impregnation was carried out for 30 min. at 125° C. and a pressure of 10 bar (nitrogen gas). At the end of the impregnation the temperature was increased to a digestion temperature of 164° C. and the pressure was gradually reduced to steam pressure. Concurrent digestion was started at said digestion temperature and pressure, the free digestion liquid being caused to circulate through the circulation digester from the top and down for a period of 60 min. Additionally 40 kg white liquor (EA) per ton of wood was added initially during the concurrent digestion. The countercurrent digestion was started upon completion of the concurrent digestion, whereupon 10 liter digester liquid was gradually pumped in and allowed to displace the same amount of black liquor for 60 min. The temperature was maintained constant at 164° C., as well as the liquid/wood ratio, during the time of 60 min. that the countercurrent digestion was in progress. The concentration of white liquor was calculated so that approximately 12 g effective alkali (EA) per liter remained at the end of the countercurrent digestion. The extended displacement phase then followed and took place at the same temperature (164° C.). It commenced with white liquor having a concentration of 10 g effective alkali per liter being added to displace spent liquor out of the circulation digester. 14.4 liter spent liquor was displaced in this way over a period of 180 min. The digested chips were then transferred to a propeller-operated disintegrator to be defibered for 15 min. The yield was determined after washing and thickening the unscreened pulp thus obtained.
Test 2
Test 1 was repeated, the only difference being that the temperature during the digestion process was increased 2° to 166° C. and the amount of white liquor added during the concurrent digestion was increased to 50 kg per ton calculated as effective alkali. The pH value of the liquid containing EDTA was 6.2.
Test 3
Test 1 was repeated for comparison, but the steamed chips were not subjected to any treatment with EDTA. Instead they were digested immediately under the same conditions. The impregnated chips had an effective alkali content of 11.8 g/l.
Test 4
Test 3 was repeated for further comparison, the only difference being that the temperature during the digestion process was lowered 2° to 162° C. The impregnated chips had an effective alkali content of 12.1 g/l.
Test 5
Test 3 was repeated, with the difference that the chips were impregnated with black liquor instead of white liquor, the amount of white liquor being increased to an equivalent extent during the concurrent digestion in order to achieve the necessary content of effective alkali, and that the temperature during the digestion process was lowered 2° to 162° C. The chips impregnated with black liquor contained no effective alkali (pH 10.8).
The results of the five experiments are given in the following Table 1. "Alkali consumption" refers to the totally consumed effective alkali (EA) in kg per ton of wood calculated as absolutely dry.
TABLE 1______________________________________ Invention Reference Test 1 Test 2 Test 3 Test 4 Test 5______________________________________EDTA, kg/ton wood 2.0 2.0 0 0 0Digestion temp., °C. 164 166 164 162 162Alkali consumption 172 182 181 171 168Yield, % of wood 46.3 45.0 44.6 45.4 45.6Kappa number 13.7 10.8 16.8 20.1 20.7Viscosity, dm.sup.3 /kg 1120 1010 1087 1164 1160Brightness, ISO 36.5 38.1 33.5 32.1 --Mn, ppm 31 30 92 107 --Mg, ppm 79 50 377 405 --Ca, ppm 1043 1003 1688 1805 --Cu, ppm 1 3 54 27 --Fe, ppm 41 25 22 58 --Tensile index, 80 80 -- 80 80kNm/kgBeat revolutions, 1100 1200 -- 1350 1000PFIDrainage resistance, 15.5 15.5 -- 15.5 15.0°SRDensity, kg/dm.sup.3 630 640 -- 640 630Air resistance, 2.3 2.6 -- 3.5 3.3sec/100 mlBurst index, MN/kg 5.6 5.4 -- 6.1 5.9Tear index, Nm.sup.2 /kg 26.5 25.6 -- 19.1 19.7______________________________________
A high tear index is obtained per se with the digestion process including a final extended displacement phase at digestion temperature, known as the ITC technique, used in the tests. This can be seen from the reference Tests 4 and 5. A lower tear index, normally at the level 15-16 Nm 2 /kg, is obtained without this ITC technique. The pulps produced according to the invention have tear indexes of 26.5 and 25.6 Nm 2 /kg at a tensile index of 80 kNm/kg, as compared with 19.1 and 19.7 Nm 2 /kg for the reference pulps. This result is very surprising. The difference is in itself surprising but even more surprising is that the difference is so great. Such high tear index values have not previously been measured for pulp made of Scandinavian softwood. Not even Douglas firs, which have the strongest fiber, produce pulps with such high tear index values.
The experiments also show that the pulps according to the invention are just as easily beaten as the reference pulps, and they have the same density despite considerably lower kappa number. The high permeability to air (low air resistance) which indicates good drainage properties in washing equipment for the pulp, is also remarkable. This was confirmed both visually and sensorially since the pulps according to the invention were dewatered extremely easily when being further processed and had the same rugged character as a high yield pulp. This may possibly be the explanation for the negligibly lower burst resistance.
Extrapolation of the yield values obtained to the kappa number interval 12-16 indicates that the pulps according to the invention give 2.5-3.0% higher yield than the reference pulps. 6-7% more pulp can thus be produced from the same quantity of raw material irrespective of whether the pulp is bleached or unbleached.
Extrapolation of the viscosities obtained to the kappa number interval 12-16 indicates that pulps according to the invention show viscosities 150-200 SCAN units (dm 3 /kg) higher than the reference pulps. Normally a lower viscosity indicates poorer strength properties. The pulps according to the invention surprisingly show a different and higher level for this relationship. The pulp according to Test 2 has a viscosity of 1010 dm 3 /kg and a tear index of 25.6 Nm 2 /kg, as compared with the reference pulps according to Tests 4 and 5 for which the mean value of the viscosity is 1162 dm 3 /kg, but the tear index is 19.4 Nm 2 /kg, i.e. the tear index is 32% higher for the invention than for the references, despite lower viscosity. The reject percentage upon screening through 0.15 mm slits was also determined in Test 2 and proved to be below a level of 0.1% of the pulp. For an ITC-pulp this value is usually just below 0.5%.
Extrapolation of the brightness values obtained to the same kappa number shows that the pulps according to the invention are 1.5-2.0 ISO units brighter than the reference pulps.
The mechanisms causing these surprising results are not fully explained. Without being tied to any explanations, however, a decrease in the manganese content probably has at least a certain significance. According to Tests 1 and 2 treatment with sequestering agent (EDTA) enabled a reduction in the manganese content from about 100 ppm (calculated on absolutely dry pulp) to 30 ppm. Manganese reciprocates or alternates between the valency levels +4 (MnO 2 , pyrolusite) and +6 (MnO 4 --, green-coloured ion) in a redox cycle continuously generating free radicals (OH·) which break down the carbohydrates in accordance with a known pattern. The process is known as the Haber Weiss cycle and is described in Trieselt W., "Chemistry of catalytic degradation during hydrogen peroxide bleaching", Melliand Textilberichte V51 (1970), page 1094.
EXAMPLE 1
Test 6
Steamed chips according to Example 1 were treated with EDTA dissolved in a liquid, in accordance with the present invention. The liquid used was black liquor obtained from Experiment 2 in Example 1, and was therefore partially freed from manganese. The quantity of EDTA was 0.005 kg, and this was mixed with about 9 liter black liquor. The liquid/wood ratio was 5.5:1. The pH value of the black liquor containing EDTA was 10.3. The treatment with EDTA was performed in a circulation digester for 60 min. at 110° C. and a pressure of 10 bar, the black liquor being circulated the whole time. Free liquid was then emptied from the digester in an amount corresponding to 65% of the total content of free and bound liquid. 9 liter of the same black liquor was added and allowed to circulate for another 60 min. at an increased temperature of 125° C. and a pressure of 10 bar. Free liquid was then emptied from the digester in a quantity corresponding to 65% of the total amount of liquid.
After the pre-treatment with EDTA 120 kg white liquor per ton wood was added, calculated as effective alkali, after which the chips were digested in accordance with Test 1 in Example 1.
Test 7
Test 6 was repeated, the only difference being that the temperature during the digestion process was increased 3° to 167° C. The pH value of the black liquor containing EDTA was 10.7.
Test 8
Test 6 was repeated with the difference that the treatment with EDTA in black liquor was continued for 25 min. instead of 60 min. and subsequent washing with black liquor for 20 min. instead of 60 min., and that the temperature during the digestion process was 165° C. The pH value of the black liquor containing EDTA was 11.3.
The results of the three experiments are given in the following Table 2.
TABLE 2______________________________________ Test 6 Test 7 Test 8______________________________________EDTA, kg/ton wood 2.0 2.0 2.0Digestion temp., °C. 164 167 165Alkali consumption 185 184 183Yield, % of wood 45.3 43.9 45.0Kappa number 12.4 9.1 11.9Viscosity, dm.sup.3 /kg 1067 886 1017Brightness, ISO 38.5 41.4 38.9Mn, ppm 49 54 73Mg, ppm 80 92 149Ca, ppm 587 783 838Cu, ppm 10 13 17Fe, ppm 28 26 27Tensile index, kNm/kg 80 80 80Beat revolutions, PFI 1100 1500 800Drainage resistance, °SR 15 16 15Density, kg/dm.sup.3 620 630 630Air resistance, 2.2 2.7 3.0sec/100 mlBurst index, MN/kg 5.4 5.3 5.8Tear index, Nm.sup.2 /kg 27.3 26.6 21.4______________________________________
Although black liquor (with metals partially removed) was used as liquid in the EDTA treatment and the digestion was carried out so that still lower kappa numbers were obtained, the tearing resistance in Tests 6 and 7 was increased even more than in the pulps according to Tests 1 and 2. A tendency towards slightly greater need for beating of a pulp with kappa number 9.1 according to Test 7 can possibly be discerned. Other mechanical properties of the pulps according to this example are substantially the same as for the pulps according to Tests 1 and 2.
At the same kappa number Tests 6-8 gave digestion pulps with almost the same high yield as Tests 1 and 2.
The viscosity and brightness were also on the same levels as for the pulps according to Tests 1 and 2.
It is remarkable that, despite the higher content of manganese in Test 6, namely 49 ppm, a somewhat higher tearing resistance was obtained than with the digestion pulps according to Tests 1 and 2, the latter having manganese contents of 31 and 30 ppm, respectively. This indicates that treatment with a sequestering agent in accordance with the present invention has a surprising effect in addition to that derived from the formation of complexes and displacement to reduce the metal content in the wood.
Test 9
Steamed chips according to Example 1 were treated with 2.0 kg EDTA per ton of wood, in accordance with the present invention. EDTA was mixed with 140 kg white liquor, calculated as effective alkali, per ton of wood and the white liquor containing EDTA was supplied to the circulation digester for pre-impregnation of the chips under the same conditions as in Test 1, except that at the end of the impregnation the temperature was increased to 167° C. Thereafter digestion of the ITC type was performed in accordance with Test 1, but at said higher digestion temperature of 167° C. Thus in this experiment no EDTA metal complexes were removed before the digestion.
The results are given in the following Table 3.
TABLE 3______________________________________ Test 9______________________________________EDTA, kg/ton wood 2.0Digestion temp., °C. 167Alkali consumption 184Yield, % of wood 43.8Kappa number 10.2Viscosity, dm.sup.3 /kg 886Brightness, ISO 38.3Mn, ppm 50Mg, ppm 245Ca, ppm 1290Cu, ppm 38Fe, ppm 20Tensile index, kNm/kg 80Beat revolutions, PFI 2300Drainage resistance, °SR 15.5Density, kg/dm.sup.3 660Air resistance, sec/100 ml 3.5Burst index, MN/kg 6.1Tear index, Nm.sup.2 /kg 24.5______________________________________
As is clear from the above results, the tearing resistance of also this pulp shows a considerable improvement over the reference pulps according to Tests 4 and 5, as well as being clearly better than the reference pulps in other respects, within the same kappa number interval. The results must be deemed surprising also in view of the fact that no withdrawal of liquid containing metals was performed.
As is evident, the manganese content in the pulp has been halved as compared with the reference experiments.
Test 10
The pulp obtained from Test 1 was subjected to delignification with oxygen gas supplied in excess. In each delignification 100 g pulp, calculated as absolutely dry, was supplied to an autoclave and varying quantities of NaOH were added. The pulp had a consistency of 10%. Delignification was carried out at a temperature of 105° C. and a pressure of 5 bar over a period of 60 min.
Test 11
Test 10 was repeated with the exception that treatment with EDTA was performed before the oxygen gas treatment. 2.0 kg EDTA per ton dry pulp was allowed to act on the pulp with a consistency of 10% for 60 min. at a temperature of 70° C. The final pH value was 5.0. The pulp was then treated with oxygen gas as in Experiment 10.
Test 12
The pulp obtained from Test 4 was subjected to delignification with oxygen gas in the same way as in Test 10.
The results of the three experiments are given in the following Table 4.
TABLE 4__________________________________________________________________________ Invention Reference Test 10 Test 11 Test 12 A B C A B C A B C__________________________________________________________________________Kappa number 13.7 13.7 13.7 13.7 13.7 13.7 20.1 20.1 20.1Viscosity, dm.sup.3 /kg 1120 1120 1120 1120 1120 1120 1164 1164 1164O-stage 0 0 0 2.0 2.0 2.0 0 0 0EDTA, kg/ton woodO.sub.2 -stageNaOH, kg/ton wood 15 20 25 15 20 25 15 20 25Final pH 11.2 11.6 11.8 11.1 11.3 11.7 -- -- --Kappa number 7.6 7.1 6.9 7.3 5.6 5.7 8.6 7.7 6.8Viscosity, dm.sup.3 /kg 975 961 944 1029 972 966 980 959 920Brightness, % ISO 44.7 45.7 48.3 49.7 54.1 54.3 -- -- --__________________________________________________________________________
As is clear from the above results, pulps with kappa number 6 and viscosity 1000 dm 3 /kg can be manufactured from chips that have been EDTA-treated in accordance with the invention. Kappa number 9 is reached with the same viscosity for the reference pulp according to Test 12.
This reduction of the kappa number by 35% enables the production of finally bleached sulphate pulps of softwood with correspondingly reduced quantities of bleaching agent such as chlorine dioxide, ozone and/or hydrogen peroxide.
Thus, the expression "prior to said digestion" means that no treatment with any other chemical such as peroxide is performed after the wood has been treated with sequestering agent. The method according to the invention is thus free from such peroxide treatment before the digestion process, i.e. also before said treatment with sequestering agent. The only additional treatment is that a second stage with sequestering agent may be performed, as well as impregnation of the wood with digestion liquid if the digestion forms part of a process that also includes such impregnation.
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A method of manufacturing chemical pulp out of comminuted cellulosic fiber material comprising digesting the fiber material with digestion liquid without preceding peroxide stage. According to the invention the comminuted fiber material is treated in at least one stage prior to said digestion, in the presence of a liquid containing at least one compound having the ability to form complexes with metals existing naturally in the fiber material.
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FIELD OF THE INVENTION
[0001] The present invention relates to a lithography system comprising:
[0002] means for generating a plurality of light beamlets, and
[0003] an electron source, arranged to be illuminated by said light beamlets, said electron source comprising a plurality of converter elements at an element distance from each other for converting a light beamlet impinging onto it into an electron beamlet directed towards and focussed on an object plane.
PRIOR ART
[0004] Current lithography systems are mostly all optical, deep UV systems. These systems use light in the deep UV region, i.e. up to 193 nm. Due to the fact that these systems are all optical, the resolution is diffraction limited. The resolution of these systems is about 130 nm at present.
[0005] WO 98/54620, which is incorporated herein by reference as it fully set forth, discloses a lithography system, which will be described with reference to FIGS. 1 and 2.
[0006] In the lithography system, a light source (not shown) produces a light beam 13 , preferably in deep UV. The light beam 13 impinges on a micro lens array 1 having lenses 2 . The micro lens array 1 divides the light beam 13 in light beamlets 12 , of which only one is shown for the sake of clarity. In practice, there may be as much as 10 7 -10 8 light beamlets 12 . The lens 2 focuses the light beamlet 12 on a mask 3 with spots of, e.g., 0.4 μm diameter. Each light beamlet 12 leaving the mask 3 passes a de-magnifier 14 , which is schematically indicated by lenses 4 and 5 and an aperture 6 . However, other types of demagnifiers known from the prior art may be used instead. The demagnifier 14 focuses the light beamlets 12 with a spot size of, e.g. 0.13 μm for each light beamlet 12 , on a converter plate 7 having converter elements 8 of which only one is indicated. If, as disclosed by WO 98/54620, the converter plate 7 is constituted by a photo-cathode having a plurality of apertures a plurality of electron beamlets 15 (only one being shown in FIG. 1) is generated. Each electron beamlet 15 originates from one aperture and passes through focusing means, indicated schematically by a lens 9 . Finally, the electron beamlets 15 impinge on the wafer 10 in wafer plane 11 . If the spot size of each electron beamlet 15 is 0.1 μm (but in practise, this can even be much smaller), the lithography system is capable of writing details of 0.1 μm or smaller.
[0007] In an embodiment, described in PCT/NL00/00657, which document is incorporated herein as if fully set forth, the converter plate 7 consists of a semiconductor field emission photo-cathode array. The sensitivity of such a semiconductor field emission photo-cathode array as converter 7 for impinging UV light may be enhanced by the application of a fluorescent layer, which transforms the impinging UV light into light of a longer wavelength. The application of such a fluorescent layer is described in the international patent application PCT/NL00/00658, which document is Incorporated herein as if fully set forth.
[0008] Each converter element has an activation area on the side of the field emission array opposite to the cathodes. This activation area is much wider than the electron beamlet: usually about 2 microns wide. Each electron beamlet is projected onto a substrate, usually a semiconductor wafer.
[0009] The distance between two adjacent converter elements 8 is larger than the width of an electron beamlet resulting from a converter element. Furthermore, the width of an electron beamlet will in general be smaller than the width of a light beamlet 12 . A method of transferring a pattern onto a wafer 10 is scanning the mask 3 with the light beamlets 12 and simultaneously scanning the wafer 10 with the electron beamlets 15 . This can be done in the following way.
[0010] Mask 3 is moved in the direction of arrow P 1 and at the same time, wafer 10 is moved in the direction of arrow P 2 . Suppose the details on the mask 3 are again 0.4 μm, and the spot size of each electron beamlet 15 on the wafer is 0.1 μm. If the mask 3 is thus moved 0.4 μm, the wafer must be shifted 0.1 μm in accordance with the magnification factor provided by the demagnifier 14 . In an embodiment shown in FIG. 2, the converter elements 8 are arranged in lines and columns and the scanning direction SCAN differs from the direction of the lines of pixels. In that way, the entire pattern of a mask can be transferred, reduced in size, onto a wafer.
[0011] The resolution is thus enhanced by sharpening up pixel by pixel, using a photo-cathode with very many apertures. Thus, converting the light into electron beamlets and using a scanning technique can transfer the mask pattern transferred onto a wafer at a resolution smaller than the optical limit. This known technology is called “Multiple Aperture Pixel by Pixel Enhancement of Resolution” or “MAPPER” technology. It can be thought of as traditional projection lithography in which the mask information is split up and transferred to the water sequentially. It can also be thought of as multiple micro-column lithography in which the electron sources are blanked by the mask.
[0012] It is noted that in a MAPPER system of the prior art, the projection of each beamlet 12 from a respective lens 2 in the micro lens array 1 on the converter plate 7 must largely coincide with a converter element 8 . The demagnifying optics 14 must thus accurately match the distance of adjacent lenses 2 in the micro lens array 1 to the distance of adjacent converter elements 8 in the converter plate 7 by applying the exact (de)magnification. However, it is not necessary to obtain a precise match of the projected lens distances and the converter element distances: It is sufficient if the light spot of a certain light beamlet reaches the sensitive area of an intended converter element. The tolerance for this is a few hundred nm. Thus, the distortion requirements of the optical system in such a MAPPER system are reduced in comparison to current all-optical systems.
[0013] Research showed, however, that in a MAPPER system the relative positions of the electron beamlets on the wafer must exactly match the relative positions of the light beamlets on the mask. The pattern of the electron beamlets should only be a demagnification factor smaller than the pattern of the light beamlets. For example, if an electron beamlet is displaced by a distance x from its ideal position, than the part of the pattern on the wafer which is written by this electron beamlet is displaced entirely by that distance x.
[0014] An obvious way of solving this problem is by producing all the elements making up the MAPPER system within narrow tolerances. This would therefore mean that the different parts have to be fabricated with 10 −8 precision: the converter plate should be manufactured with a distance accuracy of 1-10 nm on the converter plate which itself has a total size of 5-50 mm and the micro lens array, which has a total size of 30-300 mm should have a distance accuracy of 5-50 nm. Furthermore, for instance the temperature has to be maintained exactly constant, the components have to be assembled absolutely stress-free and all electromagnetic fields near the electron beamlets have to be homogeneous.
[0015] A problem, which thus emerges in a MAPPER system, is that the extra components compared to known deep-UV lithographic systems were found to put a heavy burden on alignment of the different parts of the system. Furthermore, it was found that even with perfect alignment of the MAPPER system, because of tolerances between converter plates, the alignment after replacement of parts and/or of a mask would not be as perfect as it was at first. Even worse, the system would not be able to cope with slight expansion or contraction of wafers between process steps, for which the magnification between mask and wafer must be adjusted.
[0016] Recently a MAPPER system operating without a mask has been developed, which operation is disclosed in patent application PCT/NL03/00206, which is incorporated herein by reference as if fully set forth. In the maskless concept each converter element of the converter plate is activated by a corresponding light beamlet falling onto a corresponding activation area. In order to avoid cross talk (the unintended activation of a neighboring converter element), the cross section of each light beamlet should be well aligned with and well focused on an activation area. The light for activating the converter elements is preferably transported to a region close to the activation area of each converter element using optical fibers. The focusing is preferably performed using an optical assembly comprising a plurality of microlenses preferably forming a microlens array. The light is generated by a plurality of individually switchable light sources, for instance semiconductor lasers. Each optical fiber is preferably connected to a corresponding light source, and electronical or optical means are used to couple the light, generated by said light sources, into each optical fiber. The light falling on the activation area of each converter element can be switched on for instance by switching each light source on and off. The light sources or optical switches controlling the light sources are controlled using one or more computer systems. In these ways a very high data rate can be obtained, and the use of a mask to transfer a pattern onto a exposure surface of a target, most often a wafer or a mask blank, is no longer required. However, it can be easily understood that even without a mask the alignment of all other components remains extremely difficult.
[0017] For clarity the MAPPER system comprising a mask will in the rest of this application be denoted as mask-based MAPPER system and the system without a mask will be denoted as maskless MAPPER system. When both systems are addressed the term MAPPER system will be used.
SUMMARY OF THE INVENTION
[0018] It is an object of the present invention to overcome the aforementioned disadvantages of both the MAPPER mask-based and MAPPER maskless system of the prior art.
[0019] The present invention relates to a lithography system comprising:
[0020] means for generating a plurality of light beamlets, and
[0021] an electron source, arranged to be illuminated by said light beamlets, said electron source comprising a plurality of converter elements at an element distance from each other for converting a light beamlet impinging onto it into an electron beamlet directed towards and focussed on an object plane,
[0022] said lithography system further comprising control means for matching the mutual positions of the light beamlets to the mutual positions of the electron beamlets.
[0023] Specifically, it was found that the implementation of control means for adjusting the mutual positions of the light beamlets and the electron beamlets would be possible which enable an operator to make very small adjustments, usually on the order of less than 100 nm at wafer level, with a precision better than 10 nm, preferably 1 nm, in order to restore full alignment of all the components of a MAPPER system. In for instance the MAPPER mask-based system, this means a precision on the mask of about 60 nm, preferably 6 nm.
[0024] In an embodiment of the present invention said means for generating a plurality of light beamlets comprises:
[0025] at least one light source for generating at least one light beam;
[0026] a micro lens array, arranged in the light path of said light source between said light source and said electron source and comprising a plurality of lenses at a lens distance from each other, said plurality of lenses being arranged for forming said plurality of light beamlets, and for focussing said focusing said plurality of light beamlets onto said electron source.
[0027] In an embodiment thereof said at least one light source for generating at least one light beam is individually controllable. Possible individually controllable light sources include (semiconductor) lasers and light emitting diodes (LEDs), preferably arranged to form an array. The light sources can be switched on and off individually and independently from each other, even independent from a neighbouring light source in an array.
[0028] Surprisingly, it was found that the projection of the beamlets could be manipulated through adjustment means, specifically adjustment means comprising thermal means, optical means or mechanical means. Using one of these means, or better yet, a combination of these means, it has proved to be possible to make a stable and operable lithography system having a resolution smaller than 100 nm, specifically smaller than 50 nm, which would be able to work and maintain its specifications under various working conditions. In fact, by providing, in an embodiment, adjustment means which actively and continuously manipulate the positions of the light beamlets, using continuously measured positional data regarding the position of one or more light beamlets which are fed to a controller via a feedback loop, a dynamically adjusted system can be realised.
[0029] In an embodiment of the invention, the control means comprise micro lens adaptive means for actively adapting the working parameters of the micro lens array, specifically the micro lens adaptive means comprise means for adapting the physical properties of the micro lens array.
[0030] In an embodiment thereof, the means for adapting the physical properties of the micro lens array comprise means for changing the lens distance. In a specific embodiment thereof, the means for changing the lens distance comprise microlens-related thermal means for changing the temperature of the microlens array. It was found that very small changes in temperature, i.e. in the order of one hundredth K, can change the lens distance in the order of one or more nanometers.
[0031] The temperature can be changed in several ways. First, the microlens-related thermal means can be adapted to change the temperature of the micro lens array uniformly. In that way, all the lens distances are changed in the same way. Alternatively, the microlens-related thermal means can be adapted to apply a temperature profile across the micro lens array. In that way, it is possible to correct distortions.
[0032] In another embodiment of the invention, the means for changing the lens distance comprise microlens-related mechanical means for applying mechanical forces to the micro lens array. Various types of forces can be thought of. In one embodiment, the microlens-related mechanical means comprise means for applying pressure forces to the micro lens array. In another embodiment, the microlens-related mechanical means comprise means for applying tensile forces to the micro lens array. In a further embodiment, the microlens-related mechanical means comprise means for applying torsion forces to the micro lens array.
[0033] The forces may be applied to the micro lens array uniformly, In that way the lens distances are modified uniformly. It is also possible to apply the forces to the micro lens array according to a predetermined profile. In that way, distortion can be compensated. Using a computerised controller, it is possible to apply a combination of pressure forces, tensile forces and torsion forces to the micro lens array. For this, an “intelligent” controller is required, with a feedback loop feeding back measurements of the positions of the light beamlets and with a memory comprising previous settings and measurements. The controller may for instance use a neural network to store the settings and measurements, and use a genetic algorithm for finding the best settings to be used.
[0034] In another embodiment of the invention, the lithography system comprises first optical means for modifying the light from the light source illuminating the micro lens array. In a first embodiment thereof, the first optical means for modifying the light from the light source comprise a lens or system of lenses, for modifying the true or virtual focal point of the light from the light source. In this embodiment, the optical means are used to change the incoming angle of the light beam from the light source. By changing the angle of the incoming light it was found out to be possible to change the position of the focal point of each light beamlet.
[0035] In another embodiment, the first optical means for modifying the light from the light source comprise liquid crystal means for adaptively modifying the phase of the light from the light source. In an embodiment thereof, the first optical means for modifying the light from the light source comprise liquid crystal means for locally, in a plane parallel to the micro lens array, adaptively modifying the phase of the light from the light source. The liquid crystal means can be a liquid crystal (LC) layer like the one used in known LCD screen, or of a kind specifically useful for deep-UV. The LC layer is placed between transparent sheets, which may be provided with a grid or array of transparent electrodes in order to change the properties of the LC layer.
[0036] The lithography system of the current invention may further comprise mask-holding means for holding a mask between the micro lens array and the electron source, wherein the control means comprise mask adaptive means for actively adapting the working parameters of the mask. In an embodiment thereof, the mask adaptive means comprise means for adapting the physical properties of the mask. Specifically, the mask adaptive means comprise mask-related thermal means for changing the temperature of the mask. Using the thermal expansion and contraction, it was found to be possible to change the position of the details on a mask, and thus align the mask (or better, the features on the mask) with regard to the other components of the lithography system.
[0037] In one embodiment, the mask-related thermal means are adapted to change the temperature of the mask uniformly. In that way, the distance between all the mask elements changes equally. In another embodiment, the mask-related thermal means are adapted to apply a temperature profile across the mask. In that way, the mutual distance between the elements on the mask change, making it possible to compensate for distortion.
[0038] In another embodiment of the invention, the mask adaptive means comprise mask-related mechanical means for applying mechanical forces to the mask. In a first embodiment, the mask-related mechanical means comprise means for applying pressure forces to the mask. In a second embodiment, the mask-related mechanical means comprise means for applying tensile forces to the mask. In a third embodiment, the mask-related mechanical means comprise means for applying torsion forces to the mask.
[0039] In one embodiment, the mask-related mechanical means comprise means for applying forces to the mask uniformly. In this way, the distance between all the mask elements or features changes uniformly. The uniform force may be applied uniformly in the mask-plane in one of the X-direction or the Y-direction defining the mask plane. In that way the distances between the elements on the mask are in the X-direction or the Y-direction modified uniformly. The uniform forces in the X-direction and the Y-direction may also be combined, to independently change distances both in the X-direction and the Y-direction.
[0040] In another embodiment, the mask-related mechanical means comprise means for applying forces to the mask according to a predetermined profile. In that way, the distances between elements on the mask are modified in a non-uniform way, making it possible to compensate for distortions.
[0041] In a further embodiment, wherein the mask-related mechanical means comprise means for applying a combination of pressure forces, tensile forces and torsion forces to the mask.
[0042] According to another aspect of the invention, the control means for manipulating the mutual positions of the light beamlets and the electron beamlets comprise converter adaptive means for actively adapting the working parameters of the converter.
[0043] In a further embodiment thereof, the converter adaptive means comprise means for adapting the physical properties of the converter. In an embodiment thereof, the means for adapting the physical properties of the converter comprise means for changing the element distance.
[0044] In one embodiment thereof, the means for changing the element distance comprise converter-related thermal means for changing the temperature of the converter. According to one aspect thereof, the converter-related thermal means are adapted to change the temperature of the converter uniformly. This makes it possible to uniformly adjust the position of the converter elements. According to another aspect thereof, the converter-related thermal means are adapted to apply a temperature profile across the converter, thus making it possible to adjust for distortions.
[0045] In another embodiment of the means for changing the element distance, the means for changing the element distance comprise converter-related mechanical means for applying mechanical forces to the converter. In one embodiment thereof, the converter-related mechanical means comprise means for applying pressure forces to the converter. In another embodiment thereof, the mechanical means comprise means for applying tensile forces to the converter. In yet another embodiment, the converter-related mechanical means comprise means for applying torsion forces to the converter.
[0046] The converter-related mechanical means might comprise means for applying forces to the converter uniformly. In that way, all the element distances are shifted uniformly. In another embodiment, however, the mechanical means comprise means for applying forces to the converter according to a predetermined profile, thus making it possible to reduce or remove distortion.
[0047] In another embodiment, the converter-related mechanical means comprises means for applying a combination of pressure forces, tensile forces and torsion forces to the converter. In that way, several types of misalignment may be reduced or compensated.
[0048] According to another aspect of the invention, the control means comprise adaptive means for substantially matching said lens distance with said element distance by either expansion or contraction of at least one of said micro lens array and said electron source. In an embodiment of this aspect, said adaptive means comprise microlens-related thermal means for modifying said lens distance by either thermal expansion or contraction of said micro lens array. In another embodiment thereof or together with the previous embodiment, said adaptive means comprise converter-related thermal means for modifying said element distance by either thermal expansion or contraction of said electron source.
[0049] In a specific embodiment, said microlens-related thermal means comprise a microlens-related thermal controller and microlens-related thermal elements. In an embodiment thereof, said microlens-related thermal elements are arranged to generate a microlens-related heat flow to or from said micro lens array. Said microlens-related thermal controller can be arranged to control said microlens-related heat flow independence of a microlens-related control signal relating to the temperature of said micro lens array. In this arrangement, a microlens-related temperature sensor for sensing the temperature of said micro lens array generates said microlens-related control signal. In the arrangement, it is possible that said microlens-related thermal controller is arranged to control said microlens-related heat flow independence of a microlens-related control signal relating to a value of a detector signal generated by a microlens-related detector for indicating the match of said lens distance and said element distance.
[0050] In another specific embodiment, or together with a previous embodiment, said converter-related thermal means comprise a converter-related thermal controller and converter-related thermal elements. In this arrangement, that said converter-related thermal elements are arranged to generate a converter-related heat flow to or from said electron source. In this arrangement, it is furthermore possible that said converter-related thermal controller is arranged to control said converter-related heat flow in dependence of a converter-related control signal relating to the temperature of said electron source. A converter-related temperature sensor for sensing the temperature of said electron source might generate said mask-related control signal. Said mask-related thermal controller may further be arranged to control said heat flow independence of a converter-related control signal relating to a value of a detector signal generated by a converter-related detector for indicating the match of said lens distance and element distance.
[0051] A lithography system according to present invention may further comprise a mask comprising an image, and said light beamlet from each of said plurality of lenses is being focused on said mask.
[0052] A lithography system according to the present invention may further comprise an optical system being arranged for projecting said image on said electron source by said light beamlets of each of said plurality of lenses.
[0053] The control means of the lithography system according to the invention may, according to another aspect of the invention, further comprise mechanical means for applying mechanical forces to at least one of said micro lens array and said electron source for expanding or contracting of one of said micro lens array and said electron source.
[0054] The optical means of the lithography system of the invention may comprise phase shift gradient means on at least one micro lens. Such phase shift gradient means may include an LC-screen placed before or after the micro lens array. The optical means may further or next to that comprise a refractive lens before the micro lens array. In that case, the refractive lens may comprise means for displacing the refractive lens along the optical axis.
[0055] In an embodiment of the lithography system according to the invention, the control means comprise:
[0056] a comparator for continuously comparing the actual positions of the light beamlets with desired positions;
[0057] a processor for calculating a target setting of the positions, based on the comparisons of the comparator;
[0058] a controlling element for adapting at least one of the working parameters of at least one of the micro lens array, the mask and the converter until the desired positions are reached. In an embodiment, the controlling element continuously adapts at least on working parameter and maintains them at that desired positions,
[0059] measure means for measuring at least one of the mutual position of light beamlets, electron beamlets and mask features.
[0060] In an embodiment of the lithography system of the current invention the control means comprise magnetic means for actively adapting the positions of electron beamlets in the object plane. The magnetic means are suited because they can be located away from the converter plate and the object plane, making it easy to install these means, for instance in addition to the other adaptive means described above. In an embodiment, the magnetic means comprise at least one magnetic field generator for modifying the magnetic field between the electron source and the object plane.
[0061] In one embodiment, the magnetic field generator is adapted for applying a non-uniform magnetic field component between the electron source and the object plane. Using the non-uniform field, and especially by varying the field and adapting it to measured positions of the electron beamlets, makes it possible to displace the electron beamlets in the object plane and to compensate for variations in the converter plate and variations as a result of changes in an object, for instance a wafer, positioned in the object plane.
[0062] In one embodiment, the non-uniform magnetic field component is a dipole or quadrupole field. In another embodiment, the magnetic field generator is adapted for applying a field strength of the magnetic field between the electron source and the object plane, increasing uniformly in at least one direction in a plane parallel to the object plane. In still another embodiment, the magnetic field generator is adapted for applying a field strength of the magnetic field between the electron source and the object plane, increasing with the distance from the optical axis of the lithography system. In another embodiment, the magnetic field generator is adapted for applying a field strength of the magnetic field between the electron source and the object plane, the radial component increasing proportional with the distance from the optical axis of the lithography system. This various embodiments of a non-uniform magnetic field can be combined. The magnetic field can also be combined with other adaptive means described above.
[0063] In a further embodiment, the magnetic field generator is adapted for applying a continuously varying magnetic field between the electron source and the object plane. Especially, it is possible to modify or vary the magnetic field as a result of measured positions of electron beamlets.
[0064] The present invention further relates to a substrate, preferably a semiconductor wafer, processed using a lithography system described above, and to a method for processing said substrate, using such a lithography system.
[0065] Advantageously, the present invention for making fine adjustments to the beamlet projection on the converter plate which can be controlled by a simple adjustment of the temperature of either the micro lens array or the converter plate, or both, of the lithography system.
[0066] Moreover, the fine adjustment according to the present invention can also be applied to correct for an imaging mismatch between the micro lens array and the converter plate, when the dimensions of the micro lens array and/or the converter plate may be changed due to a change of their respective temperature.
[0067] It was also found out that it was possible to make such small adjustments through mechanical means or through optical means or magnetical means, or a combination of these means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] The invention will now be explained with reference to some drawings, which are only intended to illustrate the invention and not to limit its scope of protection.
[0069] [0069]FIG. 1 shows schematically a lithography system according to the prior art;
[0070] [0070]FIG. 2 shows an example of a scanning direction of pixels on a water to be lithographed;
[0071] [0071]FIG. 3 shows schematically a first embodiment of a lithography system according to the present invention, which uses converter-related thermal means for adjustment of the converter plate;
[0072] [0072]FIG. 4 shows schematically a second embodiment of a lithography system according to the present invention, which uses microlens-related thermal means for adjustment of the micro lens array;
[0073] [0073]FIG. 5 shows schematically a third embodiment of a lithography system according to the present invention, which uses mask-related thermal means for adjustment of the mask;
[0074] [0074]FIG. 6 shows an example of microlens-related mechanical means for adjusting the lithography system, working on the micro lens array;
[0075] [0075]FIG. 7 shows an embodiment of the mask-related mechanical means, working on the mask;
[0076] [0076]FIG. 8 shows an embodiment of the converter related mechanical means, working on the converter;
[0077] [0077]FIG. 9 shows optical means for adjusting the mutual position of the light beamlets and the converter elements;
[0078] [0078]FIG. 9A shows a detail of FIG. 9;
[0079] [0079]FIG. 10 shows optical means for adjusting, using adaptive optics;
[0080] [0080]FIG. 11 shows means for adjusting using magnetic means causing a rotationally symmetric diverging magnetic field;
[0081] [0081]FIG. 12 shows means for adjusting using magnetic means causing a diverging magnetic field;
[0082] [0082]FIG. 13 shows means for adjusting using magnetic means causing a partly diverging partly converging magnetic field;
[0083] [0083]FIG. 14 shows an embodiment of the MAPPER maskless system using optical fibers and demagnifying optics.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0084] [0084]FIGS. 1 and 2 have been explained above in relation to the discussion of the prior art. FIGS. 3 - 10 show a mask-based MAPPER system, however most depicted means also apply for the maskless MAPPER system. FIG. 14 exclusively shows an embodiment of the MAPPER maskless system.
[0085] In the Figures, entities with the same reference numbers as used in FIGS. 1 and 2, refer to the same entities as shown in those figures.
[0086] [0086]FIG. 3 shows schematically a first embodiment of a lithography system according to the present invention, which uses a fine adjustment of the converter by converter-related thermal means. In the converter plate 7 , as described in PCT/NL00/00657, semiconductor field emitter tips 30 are used as converter elements 8 . The adjacent field emitter tips 30 are spaced apart at an element distance D E , which indicates the intermediate distance between the respective centres of the adjacent converter elements 8 . In the micro lens array 1 adjacent lenses 2 are located at an intermediate lens distance D L , which denotes the distance between the optical axes 26 of adjacent lenses 2 .
[0087] The projection of each light beamlet 12 from a respective lens 2 in the micro lens array 1 on the converter plate 7 should largely coincide with a converter element 8 . The demagnifying optics 14 must match the lens distance D L of adjacent lenses 2 in the micro lens array 1 to the element distance D E of adjacent converter elements 8 in the converter plate 7 by applying the (de)magnification factor of D E /D L .
[0088] However, deviation may occur between the actual and desired value of the element distance D E of the field emitter tips 30 in the converter plate 7 and of the lens distance D L of lenses 2 in the micro lens array 1 , respectively, due to e.g., variations in the manufacturing of the respective parts. It is noted that the deviations mentioned here do not only relate to an overall deviation of the repeating distance of the lenses 2 and converter elements 8 , respectively, but do also relate to local variations of the intermediate distance within the lens array 1 or the converter plate 7 .
[0089] The precise matching of the actual lens distance D L and the actual element distance D E is done by adaptive means 20 which are capable of modifying and controlling the dimensions of the converter plate 7 by thermal expansion/contraction. The adaptive means 20 can heat and/or cool the converter plate 7 to change the dimensions of the converter plate 7 in dependence of the thermal expansion coefficient. The element distance D E will change accordingly. The adaptive means 20 are capable of providing a uniform temperature profile, which allows a uniform expansion of the converter plate 7 . On the other hand, in some cases a non-uniform, but controllable, expansion or contraction may be desired.
[0090] The adaptive means 20 comprise a thermal controller 21 and thermal elements 22 . In the embodiment depicted, the thermal elements 22 are arranged at the perimeter of the converter plate 7 to avoid obstruction of the incoming light beam 13 from the light source. Heat flow Q in the horizontal direction to and from the converter plate 7 , as indicated by arrows Q, is used to adjust the temperature of the plate 7 . Such thermal elements 22 may comprise lamps, IR lasers, resistive elements and/or Peltier elements to generate the heat flow Q, but other types of elements may be conceivable, just like the thermal elements for the micro lens array. In one embodiment, for instance, IR light is entered into the lithography system together with the beam 13 .
[0091] The thermal controller 21 is arranged to control the thermal output of the thermal elements 22 in dependence of a control signal. The control signal may relate to the temperature of the converter plate 7 or to a value of a detector signal that indicates the match of the electron beamlets on the detector 24 . The temperature of the micro lens array 1 may be measured by any type of temperature measurement unit 23 known from the prior art. A detector for measuring the match of the projected electron beamlets on the detector 24 may be the same type of detectors and systems described above.
[0092] Other types of thermal control signal may be conceivable as well. The temperature changes needed for the adjustments are very small. For instance, in order to obtain a change in lens distance of 5 nm, a temperature change of about 0.01 K would be sufficient.
[0093] [0093]FIG. 4 shows schematically a second main embodiment of a lithography system according to the present invention, which uses a fine adjustment of lens distance D L of the micro lens array 1 .
[0094] In the second main embodiment of the present invention, the matching of the actual lens distance D L and the actual element distance D E is done by adaptive means 20 which are capable of modifying and controlling the dimensions of the microlens array 1 .
[0095] In an embodiment thereof, the dimensions of the micro lens array 1 are modified by thermal expansion. The adaptive means 20 can heat and/or cool the micro lens array 1 to expand or, respectively, contract the micro lens array 1 . By changing the temperature of the micro lens array 1 , the dimensions of the micro lens array will change in dependence of the thermal expansion coefficient and the change of the temperature. By change of the dimensions of the micro lens array 1 , the lens distance D L will change accordingly. Thus, by controlling the temperature of the micro lens array 1 , the lens distance D L is controlled. The adaptive means 20 are capable of providing a temperature profile, which allows a uniform expansion of the micro lens array 1 .
[0096] Just like FIG. 3, the adaptive means 20 comprise a thermal controller 21 and thermal elements 22 . In the embodiment depicted, the thermal elements 22 are arranged at the perimeter of the micro lens array 1 to avoid obstruction of the incoming light beam 13 from the light source. Energy transport by a heat flow Q (e.g., by radiation or by conductive transfer) in the horizontal direction to or from the micro lens array 1 , as indicated by arrows Q, is used to adjust the temperature of the micro lens array 1 . Instead or in addition to the thermal element depicted, such thermal elements 22 may comprise lamps, lasers, Peltier elements and/or cooling gas to generate the heat flow Q, but other types of elements may be conceivable. Using for instance IR lasers or lamps, it is possible to heat the entire surface of the micro lens array, even by illumination through some of the other elements in the lithography system, like the mask. Another option may be a grid of conductive lines on the surface of the micro lens array.
[0097] The thermal controller 21 is arranged to control the thermal output of the thermal elements 22 in dependence of a control signal, which may relate to the temperature of the micro lens array 1 or to a value of a detector signal that indicates the match of the electron beamlets 9 on a marker in the wafer plane.
[0098] Any type of temperature measurement unit 23 known from the prior art, capable of accurately measuring temperature, may measure the temperature of the micro lens array 1 . A detector for measuring the match of the electron beamlets on the converter elements 8 may be a conventional light optical system, for instance using markers on both the micro lens array and the converter.
[0099] Some embodiments of detector 24 , using pattern detection, is depicted in FIG. 4 as I and II. In I, the detector 24 comprises an aperture 60 having at least two openings. The openings are for instance aligned with electron beamlets 15 when the adjustments means are in equilibrium state. Behind the aperture's holes, detectors 61 are located. By measuring the signals on the detectors and by comparing these signals, the distance between beamlets and the absolute position of the beamlets can be calculated. So in this embodiment, there is one opening and one detector for each beamlet.
[0100] In another embodiment of detector 24 , shown in II, the aperture plate 60 has one opening located between electron beamlets, and again behind each hole one detector. Instead of these detectors, many other detectors for measuring the location of electron beamlets are possible.
[0101] It will be appreciated that the adaptive means 20 according to present invention may also be used when a mismatch between D L and D E occurs when during operation of the lithography system, the temperature of the micro lens array 1 or electron source 7 changes. Then, the adaptive means may (dynamically) correct the mismatch by adjusting one of the respective temperatures.
[0102] Also, it will be appreciated that adaptive means 20 according to the present invention may be applied together in a MAPPER system according to the present invention to provide adaptation of the dimensions of both the micro lens array 1 and the converter plate 7 . In such a MAPPER system the micro lens array 1 may be heated and the converter plate 7 may be cooled, or vice versa. Advantageously, by joint operation of adaptive means 20 a change of temperature of micro lens array 1 and converter plate 7 can be smaller for a given matching of D L and D E , in comparison with a MAPPER system, which would use only a single adaptive means 20 .
[0103] In FIG. 5 a third embodiment of the present invention is shown. In this embodiment, the thermal means change the temperature of a mask when present in the lithography system. The system is further equal to the system of FIGS. 3 and 4.
[0104] In a second main embodiment, various specific embodiments of which are shown if FIGS. 6 - 8 , the control means comprise mechanical means for applying mechanical forces to various parts of the system. By applying mechanical forces, it also showed possible to adjust the physical dimensions of various main components of a MAPPER system. Again, identical reference numerals show identical components.
[0105] The basic layout of the embodiments shown in FIGS. 6 - 8 is identical. A detector 24 measures the deviation of a specific main component, like the micro lens array, the mask or the converter. A controller 21 compares the measured values with the desired values. The controller further comprises, in its memory, information regarding the response of that specific main component to alterations and/or specific settings or values of the mechanical means. Using a feedback loop, the controller checks changes made to the mechanical means, and their effect on the dimensions and the mutual alignment of the light beamlets and converter elements. If so desired, all these parameters can be inputted into a neural network running on a computer processor, which is part of the controller. Using the neural network, the adjustments can be calculated.
[0106] [0106]FIG. 6 shows the mechanical means working on the micro lens array. FIG. 7 shown the mechanical means working on the mask, and FIG. 8 shows the mechanical means working on the converter. In these embodiments, the mechanical means 22 only apply pressure and/or traction forces to the main components. It is also possible to add mechanical means for applying torsion forces, preferably in the plane of the main components, substantially perpendicular to the optical axis of the lithography system. In this way, not only the lens distance or element distance is changed, but also the pattern of the lenses or converter elements.
[0107] In an embodiment, shown in FIGS. 6 - 8 , the forces are applied in the plane of the elements like the converter, micro lens array or mask. The forces compress or expand these elements in one direction, or the other direction, or both. In this way, it is possible to adjust the sizes in an X-direction, and/or an Y-direction. In the figures, only forces F in the Y-direction are shown (in FIG. 6, the X, Y and Z axes are indicated).
[0108] A third main embodiment of the current invention uses optical means for adjusting the mutual positions of the light beamlets and the converter elements. This is shown in FIG. 9. Again, detector means 24 are connected to control means 21 , and the control means are connected to the optical means 40 via actuator 45 . In the embodiment shown in FIG. 9, a lens is placed before the micro lens array. This can also be a system of lenses. By moving the lens back and forth along the optical axis O of a MAPPER system, the angle α (with regard to the micro lens array) of each virtual ray of the light beam 13 is changed. In FIG. 9, numeral 40 depicts the lens in a first position, and numeral 40 ′ with the lens in striped lines depicts the lens at a second position, causing the rays to impinge on micro lens array 1 at a different angle. In that way, the focal point of each beamlet I having the microlens array is displaced in a direction substantially perpendicular to the optical axis of the lithography system. Thus is has proven to be possible to shift the position of the light beamlets very small distances.
[0109] In FIG. 9A, a detail of the lithography system is depicted, showing part of the micro lens array and part of the optical means, demonstrating the effect of the specific optical means described in FIG. 9. In the embodiment depicted, an element 40 having a virtual focal point is used. The striped lines 41 show the virtual light rays from light beam 13 , coming from the virtual focal point. The striped lines 42 indicate the light rays from light beam 13 without element 40 . This drawing thus clearly shows the effect of an element 40 having a virtual focal point: the focal point of the depicted light beamlet is shifted an amount D z downward and an amount D y to the right.
[0110] In another embodiment an adaptive mirror is used as optical means. In this way, the angle of each virtual light ray of the light beam can be changed.
[0111] In FIG. 10, an embodiment is shown using adaptive optics as adjustment means. In this embodiment shown, an adaptive mirror 50 is used. By changing the profile of the mirror using e.g. actuators exerting a force F on the reflective surface, the shape of the wavefront can be adapted. Especially, the profile of the wavefront can locally be changed. By changing the wavefront, the position of the light beamlets can be modified. Also, the position of the adaptive mirror 50 can be modified using actuator 45 .
[0112] In FIGS. 11 - 13 , several embodiments of the adjustment means are shown using magnetic means. In these embodiments, the control means control the form of the magnetic field, which directs the electron beams from the converter element to the wafer. In this way the distance between the electron focus positions on the wafer can be modified in a controlled manner. When the magnetic field between the converter plate and the wafer is perfectly homogeneous, the distance between the electron focus points is equal to the distance between the electron emission points on the converter plate. It was found at a later stage, that a small contraction or expansion can be obtained if one or more electrical current carrying coils are added which create a diverging or converging magnetic field.
[0113] In FIG. 11, main coils 60 are provided to create a homogeneous B field between the converter plate 7 and the object (wafer) 10 . Additionally, smaller coils 61 are arranged around one of the main coils 60 to obtain a magnetic field between the converter plate and the wafer with a radial component proportional to the distance from the axis of the system. The vector field in FIG. 11, indicated with numeral 62 , shows a top view of the actual magnetic field component in the X and Y direction (as defined in FIG. 3) The B-field is rotationally symmetric and diverging or converging. The same effect can be obtained by changing the current in the upper or lower coil 60 with respect to the other coil, or by displacing the coils along the optical axis O, thus moving the electron beamlets away from the centre of the coils 60 .
[0114] Additional coils may be arranged to realise a magnetic field between the converter plate and the wafer having a radial component, which is proportional to the distance at the axis of the system to the power n, n being a natural number, for example 3. The distance between the electron focus positions is thus increased or decreased with respect to the distance between the electron emission points. The displacement of the electron focus positions with respect to the emission positions is then proportional to the distance from the axis of the system to the power n.
[0115] In FIG. 12, elongated current conducting lines 70 , 70 ′ are arranged for creating a magnetic field, which is proportional with the distance from the X-axis of the system. The field is symmetric in the X-axis. In this way, it is possible, by changing the strength of the magnetic field, to uniformly increase the distance between the electron focus points only in the X-direction. In an equivalent manner, the same effect can be obtained in the Y-direction. Again, a vector field 63 is shown to demonstrate the actual magnetic field component in the X and Y direction.
[0116] In FIG. 13, additional coils 64 are arranged. In these coils, the current runs in the same direction. In this way, a magnetic field between the converter plate and the wafer is realised having a radial component, which is proportional to the distance at the axis of the system to the power n, n being a natural number, for example 3. The distance between the electron focus positions is thus increased or decreased with respect to the distance between the electron emission points. The displacement of the electron focus positions with respect to the emission positions is then proportional to the distance from the axis of the system to the power n.
[0117] It is also possible to run currents through the converter plate or conductors or conducting layers on the converter plate and through the substrate or layers on the substrate. In this way, a magnetic field component between the substrate and the converter plate and directed more or less in a plane parallel to these planes can be established. In this way, no additional coils are needed.
[0118] In a further embodiment, the above-mentioned magnetic means may be combined. The magnetic means can also be combined with the other adjustment means described above.
[0119] Specifically, there are several specific modifications of the magnetic field which can be used:
M overall Δr(:)r M x Δx(:)x, Δy = 0 M y Δy(:)y, Δx = 0 M x , M y Δx(:)x, Δy(:) − y Distortion Δr(:)r 3 Spiral distortion Δφ(:)r 3
[0120] Instead of a lens, it is also possible to use means for changing the phase of (parts of) the light beam. This can for instance be done using an liquid crystal layer between transparent electrodes, much like a liquid crystal display (LCD), but without the polarizers, and other elements.
[0121] [0121]FIG. 14 shows an embodiment of the maskless MAPPER system. Each individually controllable light source comprises an optical fiber 46 , having a first end directed to a converter element 8 and a second end arranged for receiving light. Between the first end and the converter plate 7 an optical assembly focuses the light coming out of one optical fiber 46 . Preferably the optical assembly comprises a plurality of microlenses 43 thus forming a microlens array. Preferably the microlens 43 is positioned at the tip of each fiber. In this specific embodiment the light coming out of the optical fiber 46 is not directly focused on the activation area 47 of the converter element 8 . It is however possible to focus the emitted light directly on the converter plate 7 . The microlenses 43 first focus each light beam from an optical fiber 46 in a small spot of typically 200-2000 nm in the plane 45 . The plane 45 is subsequently projected, using demagnifier 44 , onto the converter plate 7 . The demagnifier can be a 1:1 projector, or may be capable of projecting at a reduced size, for instance 1:4.
[0122] In FIG. 14, furthermore, an aperture plate 40 and electrostatic deflection strips 41 are shown. The electrostatic deflection strips 41 are connected to a power source 42 . In this embodiment, the scanning of beamlets is performed by electrostatic means. The electrons are first accelerated towards aperture plate 40 . In the second part of their trajectory, after passing the aperture plate 40 , the electron beamlets are deflected by strips 41 , which carry voltages, alternatively positive and negative. The combination of a focussing magnetic field (not shown) and an electrostatic field deflects the electrons in a direction perpendicular to both magnetic and electrostatic field.
[0123] It can be easily understood that the same kind of alignment problems occur with respect to the micro lens array and the converter plate as discussed and shown before regarding the mask-based MAPPER system.
[0124] The different embodiments shown can also be combined. In that way, especially when using an intelligent controller, it can be possible by controlling the temperature of all the components and by applying mechanical forces to various components and manipulating various optical means, to fully align the lithography system, and even to adjust the alignment dynamically. Using fuzzy logic or neural networks or other techniques known to a man skilled in the art, it is thus possible to dynamically align the system, and keep it aligned during various operating conditions. In the controller in such an embodiment, positional data regarding the light beamlets and other measured parameters would be fed to the controller by a feedback loop.
[0125] It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. The scope of the invention is to be limited only by the following claims. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the spirit and scope of the present invention.
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The present invention relates to a lithography system comprising:
means for generating a plurality of light beamlets, and
an electron source, arranged to be illuminated by said light beamlets, said electron source comprising a plurality of converter elements at an element distance from each other for converting a light beamlet impinging onto it into an electron beamlet directed towards and focussed on an object plane,
said lithography system further comprising control means for manipulating the mutual positions of the light beamlets with respect to the converter elements.
These control means can be of optical, thermal, mechanical or magnetical nature, and work on for instance the micro lens array, the converter plate, and the mask.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority to and the benefit of U.S. Provisional Patent Application 60/861,132 filed on Nov. 27, 2006 by Tracey Barnes Priestley entitled “Gift Wrapping System and Methods of Use” the entire disclosure of which is hereby incorporated by reference as if set forth in its entirety for all purposes.
BACKGROUND
[0002] The packaging of gifts for presentation to friends, business associates, and loved ones serves not only as a way to protect the object inside the package, create a sense of mystique about the gift that is given, but also serve as a touchstone for further interactions between the gift giver and the recipient. There is a variation in cultural attitudes towards packaging with some cultures, particularly the Japanese, placing more emphasis on the package than the gift inside (see http://www.encyclopedia.com/doc/1G1-12152251.html).
[0003] There are many ways that a gift can be presented from the giver to the recipient. A popular configuration for giving gifts is a sturdy package to shield the contents of the gift (the “box”), a decorative or fanciful cover (the “wrapping paper”), and a place to communicate a message (the “greeting card”). Other ornamental features may include a fanciful ribbon wrapped around the box (the “bow”). The bow may also serve a functional purpose of holding the wrapping paper to the box or provide an attachment point for the card. Additional ornamental features may include plastic flowers, small replicas of babies, in the instance where the gift is for a baby shower, or other indicia of the event being celebrated. Collectively these features are the “gift ensemble”.
[0004] To create the gift ensemble the giver first must determine the size of the box in relation to the gift, then select a wrapping paper, and then find a greeting card. The wrapping, box, and greeting card must then be manually assembled. The gift giver must find wrapping paper, acquire scissors to cut the paper, find tape to affix and adhere the wrapping paper around the box, and then use tape or a bow to affix the greeting card to the gift. In some places this can require a trip to three or more different stores where each of the items are located, followed by time taken to assemble the gift ensemble.
[0005] What is true in United States, as in other modern societies, is that people demand convenience. They do not have time to visit three or more stores to create a gift ensemble. Therefore there is a need so that a person can purchase a pre-assembled gift ensemble to reduce the time to create their own gift ensemble.
[0006] The prior art describes a plethora of ways to assemble gift ensembles. Notably, the prior art describes systems that use flexible coverings, voids for holding objects, containers that have collapsible walls, integrated postal cards, and mechanisms for detaching internal objects. None of these gift ensembles describe an integrated system whereby the gift ensemble has a box for holding the gift, a message printed on a portion of the box, and wrapping paper to facilitate the insertion of gifts.
SUMMARY
[0007] The inventive subject matter disclosed herein overcomes aforementioned problems in the prior art by providing a gift ensemble or a gift packaging system that has a box, a wrapper, and a protective sleeve.
[0008] In one possible embodiment the inventive subject matter is directed towards a gift packaging system that has a box with an inner surface and an outer surface, the inner surface defining an internal void for accommodating a gift, an opening located at one end of the box for receiving the gift into the void; a greeting that is imprinted on the outer surface of the box; and a pre-shaped wrapper having a complementary fit for enclosing at least three sides of the box. In this and other embodiments the gift packaging system includes an inner surface and an outer surface; and also has an embellishment, the embellishment affixed to the outer surface of the wrapper. In this and other embodiments, the gift packaging system has a protective sleeve that surrounds the wrapper. In this and other embodiments the gift packaging system has the box which further comprises a flap that is dimensioned approximately to the length and width of the box, and where one edge of the flap is affixed to one edge of the box. In this and other embodiments the gift packaging system has a flap with an upper area imprinted with a greeting. In this and other embodiments the gift packaging system has a flap has a lower area imprinted with a greeting. In this and other embodiments the gift packaging system has a greeting that is imprinted on the inner surface of the wrapper. In this and other embodiments the gift packaging system has an embellishment that may be a bow, a ribbon, an ornamental flower petal, an ornamental plant leaf, an replica toy heart, an ornamental cross, an ornamental star, an ornamental pentagon, a ornamental plant, and an ornamental animal. In this and other embodiments, the gift packaging system of claim 1 has a greeting that is an electronic system for generating an audio message. In this and other embodiments, the gift packaging system is dimensioned to accommodate a compact disc or digital video disc.
[0009] In another possible embodiment, the inventive subject matter is directed towards a kit having component parts capable of being assembled, the components in the kit being a box with an internal void capable of receiving a gift, and the box having a flap wherein the flap is folded over the top of the box, and a wrapper dimensioned to surround the box, and a greeting imprinted on the box. In this and other embodiments, the kit has component parts with a protective sleeve that is capable of overlaying the wrapping. In this and other embodiments the kit has component parts with an embellishment that is affixed on the wrapping. In this and other embodiments the kit has component parts with a tag that is affixed to the wrapping. In this and other embodiments, the kit of component parts has a gift protection material.
[0010] In another possible embodiment the inventive subject matter is directed towards a method for making a gift packaging system with the steps of selecting a box with dimensions to accommodate a gift, selecting a piece of wrapping paper to overlay an outer surface of the box, imprinting an outer surface within the wrapping paper with a greeting, leaving an opening in one end of the box to receive the gift; and allowing one end of the wrapping paper near the opening to accommodate the gift. In this and other embodiments the method also has the step of wrapping the box with a protective sleeve.
[0011] In this and other embodiments the method also has the step of selecting a box to accommodate a gift, the method including selecting a piece of material dimensioned approximately 14″-16″ in height, 5″-6″ in width, and with a pair of tabs projecting from the piece of material with dimensions of ¾″ to 1¼″ in width and 4″ ½″ to 5½″ in length, so that the tabs are attached towards the base of the material, and dividing the piece of material into approximately three equal sections, with base section having the tabs, and folding the tabs inwards towards the base section, and folding the base section upwards towards the middle section such that the pair of tabs connect overlay on the middle section, and affixing the pair of tabs to the middle section to form a box like structure, so that a industry standard CD or DVD package can be accommodated. In this and other embodiments the method also has the steps of selecting an embellishment for mounting on the wrapping paper, and then mounting the embellishment on the wrapping paper. In this and other embodiments the method has the steps of selecting a gift protection material, and surrounding the gift with the gift protection material, and inserting the gift protection material into the box.
[0012] The foregoing is not intended to be an exhaustive list of embodiments and features of the present inventive subject matter. Persons skilled in the art are capable of appreciating other embodiments and features from the following detailed description in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The following figures show embodiments according to the inventive subject matter, unless noted as showing prior art.
[0014] FIG. 1 depicts a perspective view from above of the gift packaging system showing the wrapper, the tag, and the bow.
[0015] FIG. 2 illustrates a perspective view from above showing the gift packaging system partially open and exposing the greeting card.
[0016] FIG. 3 illustrates a perspective view from above showing the gift packaging system fully open and exposing the greeting card.
[0017] FIG. 4 illustrates a cross-sectional perspective view from one side, showing the box, the greeting card, and the tissue and the bubble-wrap in the interior of the box.
[0018] FIG. 5 illustrates a three-quarters perspective view showing the greeting card and the box.
[0019] FIG. 6 illustrates a plan view of the inner surface of the wrapper.
[0020] FIG. 7 illustrates a plan view of the greeting card.
[0021] FIG. 8 illustrates an assembly of a typical gift into the greeting card and partially surrounded by the wrapper.
DETAILED DESCRIPTION
[0022] Representative embodiments according to the inventive subject matter are shown in FIGS. 1-8 wherein the same or similar features share common reference numerals. For clarity each reference number may refer to an item generally and abstractly, as well as instances of the item in the context of one or more embodiments.
[0023] The unopened greeting gift ensemble or gift package system is shown from above in FIG. 1 . The wrapper 1 is fully closed. A tag 2 and a bow 3 are affixed to flap 21 . Flap 21 overlays flap 22 and flap 24 which then overlap flap 23 . The name of the recipient can be, for example, hand-written, printed, or typed upon the tag 2 .
[0024] Now referring to FIG. 2 where the tag 2 and bow 3 are fully opened by lifting flaps 21 , 22 , 23 , and 24 of the wrapper 1 , thereby exposing the greeting card 5 . The greeting card 5 is integrated on box 8 . The greeting card 5 has an upper area and a lower area. In one embodiment, the greeting card has a greeting imprinted upon its upper area 5 A as viewed from above. In another alternative, as shown in FIG. 3 , the first greeting is imprinted upon its lower area 5 B as viewed from above. In another embodiment, the first greeting is hand-written. In a still further alternative embodiment, the greeting card 5 surface is blank.
[0025] One flap of the gift-wrap can further comprise an adhesive means. FIG. 2 illustrates such an adhesive means, a tape 11 having a protective covering 12 . The adhesive means provides, for example, security between flap 21 and flap 22 when the gift-wrap is closed.
[0026] As shown in FIG. 3 , by lifting the card flap 9 on the greeting card 5 , both the inner surface 6 as viewed from above of the box 8 and the opening of the box 7 is revealed. The inner surface 6 of the box 8 has greeting 6 A imprinted upon an area. In a further alternative embodiment, the inner surface and fourth greeting 6 A is blank. In another alternative, the upper surface of the box 8 can comprise an area upon which an individual may write, print, and/or draw. In one configuration, the individual may sign their name on the upper surface of the box 8 .
[0027] FIG. 4 shows a top view of the box 8 , the greeting card 9 , and a void 15 within the box. The void 15 can enclose tissue 9 and/or bubble wrap 10 . A gift 16 , for example, is wrapped in the tissue 9 and/or bubble-wrap 10 and inserted into the opening of the box 8 and positioned inside the box 8 . The greeting card 9 is folded back down onto the inner surface 6 of the box. Tissue 9 and bubble-wrap 10 are simply two examples of gift protection materials that may be used and as such, other materials may be used. In other configurations, the use of tissue 9 and bubble-wrap 10 is optional for a gift that does not require physical protection.
[0028] As shown on FIG. 4 , flaps 23 , 22 , and 24 , for example, are folded up and over the box 8 and held in place. The protective covering 12 of the tape 11 located on the flap 21 is removed from the tape. Flap 21 is pulled down and affixed to the adjacent flaps. FIG. 5 shows a side view of the box 8 , the greeting card 5 and the inner surface 6 .
[0029] Now referring to FIG. 6 which shows a plan view of the inner surface 110 of the wrapper 1 . In one configuration, the wrapper 1 is configured with four flaps 21 , 22 , 23 , 24 shaped as petals. The flaps are creased at fold points 121 A, 121 B, 122 A, 122 B, 123 A, 123 B, and 124 A, 124 B to cover the box 8 (not shown). To wrap the box 8 , the wrapper is creased and the box is placed inside the crease points. Flaps 22 , 24 are folded inward and flap 23 is folded upwards. These flaps are secured leaving flap 21 to receive the gift.
[0030] The flaps 21 , 22 , 23 , 24 are not limited to a petal configuration, but, may also be configured as squares, triangles, irregular shapes, and other geometric shapes the cover the box. In certain configurations, less than four flaps are required.
[0031] FIG. 7 which depicts a plan diagram of the box 8 . The box 8 is formed from a single sheet of material. Areas are defined as the greeting card 5 , the inner surface 6 and the back 250 . To assemble the box 8 , tabs 260 A, 260 B are folded inwards along creases 220 A, 230 A to form rectangular tabs. These tabs are further folded along creases 220 B, 230 B to form a defined area. Inner surface 6 is then folded upwards along creases 210 B, 210 A such that tabs 260 A, 260 B mate with areas 270 A, 270 B forming a rectangular structure with a bottom 210 .
[0032] FIG. 8 details an assembly diagram 300 of the preferred configuration of the inventive subject matter with a typical gift 320 . A typical gift 320 is inserted into the box 8 . The greeting card 5 is folded over and inserted under flaps 22 , 23 , and 24 . Optionally, a protective sleeve 310 encircles the wrapper 1 .
[0033] In one configuration, the gift wrap system is designed to accommodate a standard industry packaging for a compact disk (“CD”) or digital video disk (“DVD”). This packaging is approximately 5½″ in width, by 5″ in length, by ½″ in depth. The dimensions of the preferred configuration would be approximately 13″-14″ from the tip of flap 21 to the tip of flap 23 , approximately 10″-12″ from the tip of flap 22 to the tip of flap 24 on the wrapper 1 . the fold areas 210 , 220 , 230 , 240 on the box 8 would be approximately ⅜″ to ¾″. The protective sleeve 310 would be slightly larger than the wrapper 1 to allow for ease of insertion and removal.
[0034] Many variations in the gift packaging system exist and can be determined by those skilled in the arts.
[0035] The term greeting includes, but is not limited to, written text on the locations for the card, but, may also include ornamentation, an audio message conveyed by electronics embedded within the card, images displayed on the card, and scents that intend to convey a certain impression to the recipient of the card.
[0036] The term box includes, but is not limited to, a six sided rectangular structure that is well known in the arts. Other box like structures may have tapered edges that join at a point, or have rounded edges.
[0037] Different materials can be used for all parts of the gift packaging system, including additional embellishments. The size of the box 8 and ancillary components can be produced in various shapes and sizes suitable to accommodate a gift having any size. The wrapper can be designed and shaped and cut in any way to accommodate a box 8 of any shape and size. The box 8 can be shaped and adapted to open and be opened in different planes and different directions. The wrapper may also be pre-shaped to fit over the box.
[0038] The greeting card can be shaped and cut so that it can open or be opened in different ways.
[0039] The box can further include a pull means that enable an individual to remove the contents of the box with ease.
[0040] The gift packaging system can be used by a business for promotions, including, but not limited to, wherein custom wrappers are designed and the greeting card imprinted with a business message or the like.
[0041] The gift packaging system can be used by a consumer for special events, such as, but not limited to, wedding invitations or party favors. The gift packaging system can be used for wrapping a gift, an item of goods, an item of clothing, a toy, a financial instrument, a voucher, or an edible item.
[0042] The gift packaging system can be custom made. The design of the gift packaging system can include themes, such as forest or woodland themes, countryside themes, urban themes, animal themes, or romantic themes. Also, the colors of the gift packaging system can be matching, clash, or both.
[0043] The gift packaging system provides a simple and inexpensive solution the need of the individual choosing a box, gift-wrap, and greeting card form what is otherwise, at present, a vast selection of choices.
[0044] The flap covering the box may also have translucent materials so that the message can be seen through the flap.
[0045] The gift packaging system may include box or wrapping materials such as, but not limited to, paper, card, cardboard, cellulose, textile, such as cotton, flax, linen, nylon or plastic materials, such as polyethylene, polyethylene tetraphalate (PET), high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polyvinyl chloride (PVC), or polystyrene (PS).
[0046] The adhesive means may be selected from the group consisting of adhesive tape, an adhesive compound, an adhesive capsule, a magnet, and the like. The adhesive means can also comprise a plurality of hook and/or eye structures.
[0047] An embellishment may be any decorative feature such as a bow, a ribbon, an ornamental flower petal, an ornamental plant leaf, an ornamental heart, an ornamental cross, an ornamental star, an ornamental pentagon, an ornamental plant, or an ornamental animal.
[0048] The greeting card system can also be provided as a pre-assembled kit. As a pre assembled kit, each of the individual components are provided separately and assembled to form the gift system.
[0049] Persons skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of the parts and actions which have been described and illustrated in order to explain the nature of this inventive concept and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein.
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A gift packaging system is described that has a box that accommodates a gift; an opening located at one end of the box for receiving the gift, a greeting that is imprinted on the outer surface of the box, and a wrapper for covering the box. Also described is a kit having component parts capable of being assembled, to create a box to receive a gift and a greeting imprinted on the box. Also described is a method for making a gift packaging system that involves steps for selecting a box with dimensions to accommodate a gift; then selecting a piece of wrapping paper to overlay an outer surface of the box, then imprinting an outer surface within the wrapping paper with a greeting.
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TECHNICAL FIELD
The invention relates to silicon power semiconductor devices and, more particularly, to a device having improved edge termination.
BACKGROUND
Protection of device edges is an essential aspect of the design of high voltage semiconductor devices such as MOSFETs, IGBTs, MCTs, bipolar transistors, thyristors, and diodes. The edge protection, or edge termination structure, must perform the function of distributing the applied voltage over a wider region on the surface of the device than it occupies within the silicon substrate, hereby ensuring that the electric field at the surface is low enough to prevent arcing outside the silicon substrate or avalanche breakdown within the substrate near its surface.
Various edge termination techniques have been developed, including, for example, field plate (FP), described in F. Conti and M. Conti, “Surface breakdown in silicon planar diodes equipped with field plate,” Solid State Electronics, Vol. 15, pp 93-105, the disclosure of which is incorporated herein by reference. Another edge termination approach is field limiting rings (FLR), described in Kao and Wolley, “High voltage planar p-n junctions,” Proc. IEEE, 1965, Vol. 55, pp 1409-1414, the disclosure of which is incorporated herein by reference. Further edge termination structures utilized junction termination extension (JTE), described in V. A. K. Temple, “Junction termination extension, a new technique for increasing avalanche breakdown voltage and controlling surface electric field in p-n junction,” IEEE International Electron Devices Meeting Digest, 1977 Abstract 20.4, pp 423-426 and variable lateral doping concentration (VLD), described in R. Stengl et al., “Variation of lateral doping as a field terminator for high-voltage power devices”, IEEE Trans. Electron Devices, 1986, Vol. ED-33, No. 3, pp 426-428, the disclosures of which are incorporated herein by reference.
Typically, a planar diffusion technique is used to produce a P-N junction diode, which yields a cylindrical junction. Because of the curvature at the edge of the junction it produces a greater electric field than an ideal planar junction. As a result, the breakdown voltage of a cylindrical junction diode is substantially lower than that of an ideal planar junction diode. Edge termination techniques are used to reduce the concentration of the electric field in a cylindrical junction diode.
U.S. Pat. No. 6,215,168 B1 to Brush et al., the disclosure of which is incorporated herein by reference, describes a semiconductor die that comprises a heavily doped silicon substrate and an upper layer comprising doped silicon of a first conductivity type disposed in the substrate. The upper layer includes an active region that comprises a well region of a second, opposite conductivity type and an edge termination zone comprising a junction termination extension (JTE) region that includes portions extending away from and extending beneath the well region. The JTE region is of varying dopant density, the dopant density being maximum at the point beneath the junction at the upper surface of the upper layer of the JTE region with the well region. The dopant density of the JTE region decreases in both lateral directions from its maximum point.
Finding an improved way to reduce the electric field at the junction of the active area and the JTE region of a power semiconductor device, the JTE region having a laterally constant or varying (VLD) dopant density, and thereby increasing its breakdown voltage remains a highly desirable goal.
SUMMARY
One embodiment is directed to a semiconductor device comprising a doped semiconductor substrate and an upper layer comprising doped semiconductor material of a first conductivity type disposed on the substrate. The upper layer comprises an upper surface and includes an active region with a well region of a second, opposite conductivity type and an edge termination zone that comprises a junction termination extension (JTE) region of the second conductivity type. The JTE region comprises portions extending away from the well region. A number of field limiting rings of the second conductivity type are disposed at the upper surface in the junction termination extension region.
Another embodiment is directed to a semiconductor device comprising a doped semiconductor substrate and an upper layer of semiconductor material of a first conductivity type disposed on said semiconductor substrate, said upper layer having an upper surface and including an active region that comprises a well region of a second, opposite conductivity type and an edge termination zone that comprises a first junction termination extension (JTE) region of the second conductivity type, said region comprising portions extending away from said well region, and a second junction termination extension (JTE) region of the second conductivity type extending away from said well region disposed in the first junction termination extension region.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A shows a cross-sectional view of a semiconductor die including a JTE region as an edge termination structure according to a first embodiment of the invention,
FIG. 1B shows a cross-sectional view of a semiconductor die including a JTE region as an edge termination structure according to a second embodiment of the invention,
FIG. 2 shows a graph of the current-voltage-characteristic under reverse bias of a power semiconductor device with the die of FIG. 1 , and
FIG. 3 shows a detail of the graph of FIG. 2 .
DETAILED DESCRIPTION
FIG. 1A schematically depicts a semiconductor die 100 according to a first embodiment of the present invention. The semiconductor die 100 comprises an N-doped upper layer 101 which includes an active region well 102 , which can be e.g. a p-emitter of a diode or a p-body of an IGBT, and a JTE region 103 , which are both p-doped. The upper layer 101 further comprises a number of p-doped field limiting rings 109 , 110 and 111 in the JTE region 103 . A metal contact 104 and a dielectric layer 105 overlie, respectively, the active region 102 and the JTE region 103 with the field limiting rings 109 . The JTE-region 103 extends deeper into the upper layer in the direction perpendicular to the upper surface than the field limiting rings 109 .
It is recognized that the conductivity types of the dopants in layer 101 , well 102 , JTE region 103 , and field limiting rings 109 , 110 and 111 , N, P, P, and P, respectively, can also be of the opposite conductivity types, i.e., P, N, N and N, respectively.
The active region 102 and the field limiting rings 109 are preferably heavily doped with a dopant concentration of the order of 10 18 cm −3 or above, while the JTE region 103 is typically doped with a concentration of the order of 10 15 cm −3 . In one embodiment of the invention, the field limiting rings 109 , 110 and 111 comprise substantially the same dopant density. In another embodiment of the invention, the dopant density of the field limiting rings increases from a maximum value of the innermost field limiting ring 109 closest to the well region 102 to a minimum value of the furthermost field limiting ring 111 . The field limiting rings preferably comprise substantially the same width.
From a point of maximum dopant density 107 , that lies substantially directly beneath the junction of JTE region 103 with active region 102 at the upper surface of upper layer 101 , the dopant density of the JTE region 103 preferably decreases in both lateral directions, forming a variation of lateral doping (VLD) region. The VLD edge termination is therefore a special case of a JTE structure.
The JTE region 103 and the field limiting rings 109 , 110 and 111 of die 100 are preferably formed by implanting varying amounts of dopant according to known procedures described in, for example, U.S. Pat. Nos. 4,927,772, 4,667,393, and 4,648,174. The JTE region 103 and the field limiting rings can also comprise epitaxial layers, as described in U.S. Pat. No. 5,712,502.
In the case of an avalanche breakdown, the concentration of p-holes compensates the charge of the ionized dopants in the JTE region, thereby reducing the maximum electrical field strength in the area of the junction termination. If the p-hole concentration in the case of an avalanche breakdown exceeds the dopant concentration of the JTE region 103 , this mechanism no longer works and the breakdown may jump to the edge of the active region 102 .
The field limiting rings however have a dopant concentration that exceeds the concentration of p-holes in the case of a breakdown. They can therefore built up a space-charge region that partly compensates the influence of the curved junction on the electric field and therefore increases the breakdown voltage of the semiconductor device even in the case of high leakage current densities.
FIG. 1B schematically depicts a semiconductor die 100 according to a second embodiment of the present invention. The semiconductor die 100 comprises an N-doped upper layer 101 which includes an active region well 102 , which can be e.g. a p-emitter of a diode or a p-body of an IGBT, and a first JTE region 103 , which are both p-doped. The upper layer 101 further comprises a second JTE region 112 in the first JTE region 103 . A metal contact 104 and a dielectric layer 105 overlie, respectively, the active region 102 and the first and second JTE region 103 and 112 .
It is recognized that the conductivity types of the dopants in layer 101 , well 102 , first JTE region 103 , and second JTE region 112 , N, P, P, and P, respectively, can also be of the opposite conductivity types, i.e., P, N, N and N, respectively.
The lateral extension of the second JTE region on the upper surface is 20 to 200 μm, depending on the desired voltage class of the device.
The first JTE region 103 is typically doped with a dose of the order 10 12 cm −2 to 5·10 12 cm −2 , while the second JTE region is doped with a dose of the order of 10 13 cm −2 to 10 15 cm −2 . The first JTE region 103 and the second JTE region 112 can be of constant or varying lateral dopant density.
FIG. 2 depicts a computer simulation of the current-voltage-characteristic under reverse bias of a power semiconductor device with field limiting rings 109 in addition to a JTE region 103 . The characteristic shows a sharp voltage drop at the point 201 of an avalanche breakdown.
FIG. 3 shows a detail of FIG. 2 , which illustrates the influence of the number of field limiting rings 109 in the JTE region 103 on the current-voltage-characteristic. The first characteristic 302 is the characteristic of a die 100 which comprises a JTE region 103 but no field limiting rings 109 . The second, third and fourth characteristic 303 , 304 , and 305 respectively, are the characteristics of a die 100 with a JTE junction and additional three, four or five field limiting rings 109 , respectively.
The point 201 indicating a breakdown jumping of the position of the edge of the JTE to the edge of the active region is shifted to higher currents and higher voltages by employing the field limiting rings. The improvement can be achieved with a constant as well as with a varying lateral doping.
The die 100 with the edge termination according to the invention is preferably used in an IGBT-, Schottky-diode or a pin-diode semiconductor device.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention, which is defined by the following claims.
REFERENCE NUMBERS
100 device
101 upper layer
102 active region
103 JTE region
104 metal contact
105 dielectric layer
107 point of maximum dopant density
109 field limiting ring
110 innermost field limiting ring
111 furthermost field limiting ring
112 second JTE region
201 point of avalanche breakdown
302 first characteristic
303 second characteristic
304 third characteristic
305 fourth characteristic
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A The semiconductor device has a heavily doped substrate and an upper layer with doped silicon of a first conductivity type disposed on the substrate, the upper layer having an upper surface and including an active region that comprises a well region of a second, opposite conductivity type. An edge termination zone has a junction termination extension (JTE) region of the second conductivity type, the region having portions extending away from the well region and a number of field limiting rings of the second conductivity type disposed at the upper surface in the junction termination extension region.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to automated hard copy apparatus, such as inkjet printers, and more specifically to an adjustable carriage mount for aligning an automated writing instrument, such as an inkjet printhead, with respect to a printing zone of the apparatus.
[0003] 2. Description of Related Art
[0004] The art of ink-jet technology is relatively well developed. Commercial products such as computer printers, graphics plotters, copiers, and facsimile machines employ inkjet technology for producing hard copy. The basics of this technology are disclosed, for example, in various articles in the Hewlett-Packard Journal , Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No. 1 (February 1994) editions. Ink-jet devices are also described by W. J. Lloyd and H. T. Taub in Output Hardcopy [sic] Devices , chapter 13 (Ed. R. C. Durbeck and S. Sherr, Academic Press, San Diego, 1988).
[0005] [0005]FIG. 1 (PRIOR ART) depicts an ink-jet hard copy apparatus, in this exemplary embodiment a computer peripheral printer, 101 . A housing 103 encloses the electrical and mechanical operating mechanisms of the printer 101 . Operation is administrated by an electronic controller 102 (usually a microprocessor or application specific integrated circuit (“ASIC”) controlled printed circuit board) connected by appropriate cabling to a computer (not shown). It is well known to program and execute imaging, printing, print media handling, control functions and logic with firmware or software instructions for conventional or general purpose microprocessors or with ASIC's. Cut-sheet print media 105 , loaded by the end-user onto an input tray 120 , is fed by a suitable paper-path transport mechanism (not shown) to an internal printing zone 107 where graphical images or alphanumeric text is created. A carriage 109 , mounted on a carriage rod, or slider, 111 , scans the print zone 107 . An encoder subsystem 113 , 201 is provided for keeping track of the position of the carriage 109 at any given time. A set of individual ink-jet pens, or print cartridges, 115 x are releasably mounted in the carriage 109 and fluidically coupled, such as by flexible tubing 119 , to ink reservoirs 117 x (generally, in a full color system, inks for the subtractive primary colors, cyan, yellow, magenta (CYM) and true black (K) are provided; an ink fixer chemical (F) is also sometimes provided). Once a print job is completed, the print medium is ejected onto an output tray 121 . The carriage scanning axis is conventionally designated the x-axis, the print media transit axis is designated the y-axis, and the printhead firing direction is designated the z-axis. [For convenience of describing the ink-jet technology and the present invention, all types of print media are referred to simply as “paper,” all compositions of colorants are referred to simply as “ink,” and all types of hard copy apparatus are referred to simply as a “printer.” No limitation on the scope of invention is intended nor should any be implied.]
[0006] In essence, the inkjet printing process involves digitized dot-matrix manipulation of drops of ink ejected from a pen onto an adjacent paper. One or more inkjet type writing instruments (also referred to in the art as an “inkjet pen” or “print cartridge”) includes a printhead which generally consists of drop generator mechanisms and a number of y-axis aligned columns of ink drop firing nozzles of a substantially planar nozzle plate superjacent the drop generator mechanisms. Each column or selected subset of nozzles (referred to in the art as a “primitive”) selectively fires ink droplets (typically each being only a few picoliters in liquid volume) that are used to create a predetermined print matrix of dots on the adjacently positioned paper as the pen is scanned across the media. A given nozzle of the printhead is used to address a given matrix column print position on the paper (referred to as a picture element, or “pixel”). Horizontal positions, matrix pixel rows, on the paper are addressed by repeatedly firing a given nozzle at matrix row print positions as the pen is scanned. Thus, a single sweep scan of the pen across the paper can print a swath of tens of thousands of dots. The paper is stepped to permit a series of contiguous swaths. Complex digital dot matrix manipulation is used to form alphanumeric characters, graphical images, and photographic reproductions from the ink drops. Page-wide ink-jet printheads are also contemplated and are adaptable to the present invention. Thus, it can be recognized that a critical operating factor is print-head-to-paper spacing and alignment to ensure accurate dot placement.
[0007] [0007]FIG. 2 (Prior Art) schematically illustrates a typical pen-to-paper alignment scheme. The front of the carriage 109 (with respect to the leading edge of a sheet of paper 105 in the print zone 107 supported by a platen or suspended by a paper pivot apparatus (neither shown)) is used as a pivot point “A” and known manner camming mechanisms (not shown) are provided on at least one end of the slider 111 . Note that mechanical tolerances inherent in such rod adjustment mechanisms can be the source of vibration of the rod and hence the carriage and pens. Letting “Theta-X” represent the pitch angle of the printhead 201 with respect to a Y-plane, it can be recognized that Theta-X is not held when adjusting the slider up or down (as represented by the arrows Z-up and Z-down) with the carriage 109 pivoting about point “A.” Therefore, another adjustment mechanism would be required to ensure pitch axis parallelism between the printhead 201 and the paper 105 . It can also now be recognized that other degrees of freedom of the printhead 201 must be accounted for; let “Theta-Y” represent the roll angle of the printhead with respect to an X-plane, and let “Theta-Z” represent the yaw angle of the printhead nozzle columns with respect to the Y-axis. When both Theta-Z=0° and Theta-X=0°, the long axis—that is, the columns of nozzles—of the printhead 201 is parallel to the paper transport Y-axis; when Theta-Y=0°, the short axis of the printhead—that is, a line perpendicular to the columns of nozzles—is parallel to the carriage scanning X-axis.
[0008] There is a need for an adjustable carriage mount which will provide independent carriage alignment.
SUMMARY OF THE INVENTION
[0009] In its basic aspects, the present invention provides a system for aligning a writing instrument to a print medium, including: a support base having a substantially fixed position; a chassis for retaining the writing instrument; and a plurality of support mechanisms for coupling the chassis to the base, each of the support mechanisms having alignment mechanisms for independently adjusting spacing between the chassis and the base wherein pitch angle and roll angle of the writing instrument with respect to the print medium is determined by adjusting each of the support mechanisms.
[0010] In another basic aspect, the present invention provides an ink-jet hard copy apparatus, including: a base having a substantially fixed spatial orientation; a print zone having a substantially fixed spatial orientation with respect to the base; a chassis for retaining at least one ink-jet printhead device in a predetermined orientation the print zone; and a plurality of supports for coupling the chassis to the base, each of the supports being fixedly mounted to the base and each of the supports having a range of settable distance positions wherein setting the distance between the printhead device and the print zone simultaneously adjusts the printhead device pitch and roll angle with respect to the print zone.
[0011] In another basic aspect, the present invention provides a method for adjusting the spatial orientation of an ink-jet printhead to a printing zone of an ink-jet hard copy apparatus. The method includes the steps of: providing at least three independently adjustable printhead mounts for setting the distance between the printhead and the printing zone; and independently adjusting the printhead mounts to set the pitch angle and roll angle of the printhead to predetermined settings.
[0012] The method and apparatus can be automated by providing known manner sensing mechanisms for detecting real-time orientation of the printhead to the printing zone and providing signals indicative of the orientation, and automatically adjusting the printhead mounts based on the signals such that a predetermined orientation of the printhead is maintained with respect to the printing zone.
[0013] Some of the advantage of the present invention are:
[0014] it solves problems attendant to the prior art;
[0015] it provides a simple mechanism for adjusting pen-to-paper alignment whereby a printhead can be aligned to be parallel to adjacently positioned print media;
[0016] it provides for pen-to-paper height and both Theta-X and Theta-Y adjustment;
[0017] it frees the carriage rod in a scanning ink-jet device from mechanisms for adjusting pen-to-paper height, wherein the carriage rod can have better mechanical tolerances and integrity;
[0018] it substantially eliminates print quality problems induced by an adjustable, vibrating carriage rod; and
[0019] it is adaptable to a fully automated implementation.
[0020] The foregoing summary and list of advantages is not intended by the inventor to be an inclusive list of all the aspects, objects, advantages and features of the present invention nor should any limitation on the scope of the invention be implied therefrom. This Summary is provided in accordance with the mandate of 37 C.F.R. 1.73 and M.P.E.P. 608.01(d) merely to apprise the public, and more especially those interested in the particular art to which the invention relates, of the nature of the invention in order to be of assistance in aiding ready understanding of the patent in future searches. Other objects, features and advantages of the present invention will become apparent upon consideration of the following explanation and the accompanying drawings, in which like reference designations represent like features throughout the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] [0021]FIG. 1 (Prior Art) is an exemplary ink-jet hard copy apparatus in which the present invention may be employed.
[0022] [0022]FIG. 2 (Prior Art) is a schematic illustration of a typical pen carriage mount used in a scanning ink-jet hard copy apparatus.
[0023] [0023]FIGS. 3 and 3A are two views of a pen carriage and associated mounting subsystem in accordance with the present invention for a hard copy apparatus, in which:
[0024] [0024]FIG. 3 is a top view of a base plate, a carriage chassis with a carriage on a slider bar, and FIG. 3A is a perspective view of the carriage chassis with a pen carriage on a slider bar as shown in FIG. 3 but with the base plate deleted.
[0025] [0025]FIG. 4 is a perspective drawing of the base plate of FIG. 3 with carriage chassis mount subassemblies of the present invention positioned thereon.
[0026] [0026]FIGS. 5A and 5B are exploded, perspective drawings of one of the base-to-chassis mounts in accordance with the present invention.
[0027] [0027]FIGS. 5C, 5D, and 5 E are orthogonal projection drawings of the base-to-chassis mount as shown in FIG. 5B.
[0028] [0028]FIG. 6 is an exploded, perspective drawing of another one of the base-to-chassis mounts in accordance with the present invention.
[0029] [0029]FIGS. 6A, 6B and 6 C are orthogonal projection drawings of the base-to-chassis mount as shown in FIG. 6.
[0030] [0030]FIGS. 7A and 7B demonstrate the operation of the present invention as in FIG. 3.
[0031] The drawings referred to in this specification should be understood as not being drawn to scale except if specifically noted.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0032] Reference is made now in detail to a specific embodiment of the present invention, which illustrates the best mode presently contemplated by the inventor for practicing the invention. Alternative embodiments are also briefly described as applicable.
[0033] It will be recognized by those skilled in the art that the present invention is use in conjunction with precision tools, such as laser alignment tools, for setting ink-jet alignment with respect to the hard copy apparatus' printing zone. Usually this is a manufacturing process. However, it is expressly intended that the present invention can be automated for real-time printing operation as will be explained in detail hereinafter. Further explanation of the details of such state-of-the-art alignment tools is not necessary for a complete understanding of the present invention. FIG. 3 is an overhead, planar view, of an exemplary embodiment in accordance with the present invention of a base 301 , a pen carriage chassis 303 and the pen carriage 109 atop the slider 111 , as shown in FIG. 1. A perspective view of this embodiment is shown in FIG. 3A, with the base 301 removed. It will be recognized by those skilled in the art that the details of these components will vary from implementation to implementation.
[0034] The base 301 forms a structural foundation for the housing 103 and contained subsystems of the printer 101 , with an emphasis on reducing vibration and noise. Known manner base-to-housing mounting features 307 are provided as needed to suit a specific design.
[0035] The carriage chassis 303 is used as a substantially rigid mount for the slider 111 and the carriage 109 . It includes an aperture 309 such that the pens 115 x have respective printheads aligned and open to the print zone 107 of the printer 101 . Otherwise its construction details again can be expedient to a specific implementation. Critical to the present invention is the mounting construct used between the base 301 and the pen carnage chassis 303 .
[0036] In FIG. 4, the chassis 303 , slider 111 , and pen carriage 109 subassemblies have been deleted to expose preferred embodiments of four adjustable chassis mounting supports 401 , 402 , 403 , 404 , as located on the base 301 (se also notation on FIG. 3. Preferably, the supports 401 - 404 are located in both the relative front and rear of the assembly and at suitable spacing—generally as far apart as feasible for a specific implementation—to allow the greatest available adjustment resolution while still maintaining structural integrity and rendering the chassis 303 substantially impervious to vibrations (such mechanical leverage techniques are well known to persons of average skill in the art).
[0037] These front and rear chassis adjustable mounting supports 401 - 404 are detailed in FIGS. 5 A- 5 E, 6 and 6 A- 6 C. [As is known in the art, there are a variety of ways to implement hard copy printing apparatus. Therefore, terms like, “front,” “rear,” “top,” and the like, are relative to a specific design. No limitation on the scope of the invention is intended by the inventor nor should any be implied.]
[0038] As best seen in FIGS. 5 A- 5 E, the front supports 401 , 402 are mirror image constructs; a description of one relates to both. A slotted flange 405 provides for the front support 401 to be rigidly attached by any known manner fastener to the base 301 . A stanchion 407 rising from the flange 405 includes a groove bearing 409 for receiving a descending tongue 411 of a chassis mount slider 413 . The slider 413 is affixed to the chassis 303 in a known manner such as with a machine bolt (not shown) via an attachment hole 415 . The slider 413 has a protruding arm 417 incorporating a clearance hole 419 . A matching arm 421 on the stanchion 407 has a tapped hole 423 aligned to the slider arm clearance hole 419 . A threaded adjustment screw 425 and retainer clip 427 are provided such that turning the adjustment screw causes the slider 413 to ride up-and-down on the stanchion 407 via the tongue 411 and groove bearing 409 .
[0039] [0039]FIG. 6 is a perspective view of a pen carriage chassis rear support 403 / 404 . FIGS. 6 A- 6 C show planar orthogonal projections of the rear support device. As best seen in FIG. 4, the rear supports 403 , 404 are two-piece constructs with a bottom piece 601 fixedly attached—such as by screws or bolts (not shown) using fastener holes 603 , or any other known manner—to uprights 431 , 432 rising from the base plate 301 . Returning to FIGS. 6 and 6A- 6 C, a top piece 605 is fixedly attached to the chassis 303 —such as by screws or bolts (not shown) using fastener holes 607 , or any other known manner. The rear support top piece 605 and bottom piece 601 are aligned via a guide pin 609 and a socket 611 and a separately aligned set screw 613 , sleeved socket 615 , retainer clip 617 and threaded hole 619 . As shown in FIG. 3A, the pen carriage chassis 303 is provided with appropriate apertures 311 matching the attachment hole 415 for the front supports 401 , 402 and the fastener holes 607 of the rear supports 403 , 404 adapted for use with appropriate fastening mechanisms chosen for any specific implementation. The design should be such that the supports 401 - 404 are distributed with respect to the base 301 with x-axis and y-axis displacement such that the chassis 303 is substantially impervious to vibrations transmitted by motion of the carriage 109 . If necessary, an access port 313 through the chassis 303 is provided for inserting an appropriate adjustment tool into the set screw 613 .
[0040] The operation of the ink-jet pen carriage chassis mounts is schematically depicted in FIGS. 7A and 7B, greatly exaggerating possible adjustment position extremes to demonstrate the nature of the invention. All four supports 401 - 404 are used to set the z-axis, printhead(s)-to-paper distance. Theta-X, printhead pitch, and Theta-Y, printhead roll, adjustments are then fine tuned using the set screws 425 , 613 of the front and rear supports 401 - 404 . The pitch of the threads of each set screw 425 , 613 and its respective associated threaded hole in the supports 423 , 601 determine the degree of adjustment sensitivity. While four supports 401 - 404 are demonstrated, it will be recognized by those skilled in the art that other implementations can be designed in accordance with the specific implementation.
[0041] Thus, the present invention provides an ink-jet pen (or other writing instrument where printing head design and angle of alignment to the print media is critical to print quality) carriage chassis having independent supports that are individually adjustable in the pen-to-paper axis such that by adjusting each support independently, pitch and roll of the pen are also adjusted. It will be further recognized by those skilled in the art that the present invention can be employed with platen subsystems having an orientation other than horizontal as shown in the exemplary embodiments used to for this Detailed Description. It should also be noted that the alignment system described can also be adapted to a non-scanning, page-wide, printhead design ink-jet apparatus. While the adjusters have been demonstrated as supports, independently adjustable suspension type mechanisms should be considered as equivalents. Moreover, it should also be recognized that mounting the orientation adjusters to other fixed paper support subsystems, such as a vacuum box for a vacuum belt type hard copy apparatus and the like, should be considered as equivalent to having a base plate mounting.
[0042] As mentioned above, usually the alignment of an automated writing instrument to a print zone is a post-assembly, manufacturing process. However, it can now be recognized that in a hard copy apparatus requiring the ability to repeatedly provided extremely detailed prints—e.g., semiconductor mask prints, complex wiring diagrams, architect illustrations, and the like—the present invention could be automated. Alignment detectors—such as known optical or magnetic sensing devices—can be mounted on the carriage, the chassis, or to the base for providing signals indicative of current writing instrument to print zone alignment. The set screws 425 , 613 , or other known manner alignment tuning devices, can be driven by motors controlled in accordance with real-time alignment information based on the signals from the detectors. While such an automated alignment subsystem would add substantial manufacturing cost to the hard copy apparatus, the reduction in need for maintenance or servicing could be shown to be offset. Note that such a system can also be tuned to a very fine degree with precision adjustment parts and alignment detectors to reposition the printhead automatically to different thickness of print media.
[0043] The foregoing description of the preferred embodiment of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. Similarly, any process steps described might be interchangeable with other steps in order to achieve the same result. The embodiment was chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents. Reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather means “one or more.” Moreover, no element, component, nor method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the following claims. No claim element herein is to be construed under the provisions of 35 U.S.C. Sec. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for . . . ”
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A method and apparatus for setting the writing instrument distance and orientation to an adjacent platen uses independently adjustable devices positioned such that both the gap between the writing instrument and platen and the pitch and roll angles of the printhead to the platen can be aligned to predetermined appropriate settings.
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BACKGROUND OF THE INVENTION
The invention relates to a method of controlling a cage stranding machine comprising at least one stranding cage which holds a plurality of spools for the material being stranded, a removal for the stranded material and a coiling device.
The production output of stranding machines, with a given lay length of the stranded material, is a direct function of the number of revolutions of the stranding cage therefore such machines are designed for the highest possible numbers of revolution to provide maximum production output. In the past, it was customary to run the machines up to a constant operating speed for the respective quantity of stranded material to be produced and to then maintain that speed practically to the end. For example, stranding cages rated at speeds of 320 revolutions per minute were provided to strand aluminum wires. However, such a speed cannot be maintained in practice since, due to unavoidable eccentricities resulting from irregular winding of the spools in the stranding cage. In practice it is possible to operate only at a lower speed in spite of the fact that the machine is designed for the desired number of revolutions per minute. While it is certainly possible structurally, to design such a stranding machine, to operate at the given desired number of revolutions, problems will still result from the eccentricities resulting from the irregularly wound spools while they rotate about their own axes. The individual spools rotating at the same time produce different tensile stresses on the wire supplied from the spool to the stranding locations and these stresses may ultimately be s high at the given rated speeds that the respective wire is stretched until it breaks. In the case of a break in the wire, the machine must be stopped, the two wire ends must be welded together and then the machine can be started up again. To prevent this in the given example, the machine is actually operated, in spite of the given rated number of revolutions, at a lower speed of, for example 250 rpm, so that in the end the intended production output of the machine is not realized.
BRIEF SUMMARY OF THE INVENTION
It is the object of the invention to provide an improved stranding machine and a method for controlling the stranding machine, which permits high production output with gentle treatment of the material being stranded.
This is accomplished according to the invention in that the centrifugal force acting on the spool body is measured at at least one spool and the rate of revolution of the stranding cage and the removal rate of the stranded material are regulated based on the measured value of the centrifugal force. The ratio of cage revolutions to removal rate is maintained constant in correspondence with the given length of a lay of the stranded material to be produced. With the aid of this method, it is possible to operate at a lower speed at the beginning of the stranding job, when the spools lying in the stranding cage are still completely filled, but to then, with decrease of the coil diameter, to increase the number of cage revolutions. The centrifugal force acting on the spool bodies provides a measure for the decrease of the coil diameter and represents a guide variable according to which the number of cage revolutions and the removal speed are regulated. In this connection, it is sufficient to measure the centrifugal force of only one spool since, in principle, all spool are wound as uniformly as possible. However, it is advisable for the spool having the greatest starting weight to be placed into the stranding basket equipped with the spool carrier provided with a measuring location. With the aid of this method, it is possible to always operate the stranding machine in an optimum speed range. The stranding machine is initially run up to a starting number of revolutions per minute which is determined by the given centrifugal force. Then there results a progressive rise over the remaining period of operation up to the maximum permissible number of revolutions which can be maintained until the end of the stranding job so that, as a whole, a considerable increase in production results with improved quality, and breaks in the wire are practically avoided. A further advantage of the method according to the invention is that the measurement of the centrifugal force can be made without moving parts, for example by installing a so-called electrical pressure pickup in the spool bearing of one of the spool carriers. The transfer of the measurement signal may then occur either by way of a slip ring or without contact by way of a transmitter. Depending on the type of drive employed to drive the stranding machine, the removal device and the winding device, the measuring as well as the change in the number of cage revolutions per minutes and the removal rate may here take place continuously or also at given time intervals. A further advantage of the method according to the invention is that the machine does not require any additional selector circuit it which it would have to be set for different materials to be stranded. Thus, it is possible without any switching measures to initially charge the stranding machine with a stranding material having a higher specific weight, for example copper, and then with a stranding material having a lower specific weight, for example aluminum. This is insignificant for the regulation process since the given centrifugal force as the guide variable also automatically results in the respectively permissible number of cage revolutions per minute.
Measurement of centrifugal force automatically takes into account the weight of the material on the spool since the greater the weight, the greater the centrifugal force generated by the spinning spool. Another advantage of the method according to the invention is that, on the basis of the constant centrifugal force stress, the machines as a whole, including the spools and the spool bearings, are much less subjected to stresses so that there is much less wear to be noted. Since, moreover, the machines operate at a lower number of revolutions at the beginning of the stranding job, correspondingly smaller drive motors can be employed. Accordingly, the brakes for the stranding cage may also be given smaller dimensions.
An advantageous feature of the invention further provides that if the centrifugal force measuring signal is pulsating, only the respectively measured maximum value is switched to the speed control device as the cage revolution and removal rate control regulating signal. In this way, it is ensured that even if the spool being measured is wound in an unfavorable manner, the regulation permit a change only in the form of an increase in the number of revolutions.
Another advantageous feature of the invention provides that the centrifugal forces of a plurality of spools can be measured, the resulting measurement signals are fed to a comparator and the greatest centrifugal force measured is switched to the speed control device as the control signal to change the number of cage revolutions and the removal rate. Although this procedure requires higher construction expenditures, it has the advantage that, particularly in connection with large cage stranding machines operating with a plurality of spools, irregular coiling in one or several spools is already considered in the measuring result and thus it is possible to ensure, in particular, unchanging quality of the stranded material.
A further advantageous feature of the method according to the invention provides that the actual length of the lay of the resulting stranded material is continuously measured downstream of the cage stranding machine and is compared with the given lay length. The drive for the stranding machine or the removal device is regulated as a function of the resulting difference value. This permits an even more sensitive regulation and an improvement of product quality.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in greater detail with reference to schematic drawings of one embodiment. It is shown in:
FIG. 1, a cage stranding machine in the form of a block circuit diagram;
FIG. 2, a diagram of the number of cage revolutions over time;
FIG. 3, a cross-sectional view to a larger scale of a stranding cage.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The stranding system shown schematically in FIG. 1 is essentially composed of a cage stranding machine including two stranding cages 1 and 2. Stranding cage 1 is here provided with a total of twelve spools, while stranding cage 2 is provided with a total of sixteen spools. An unwinding mechanism 3 is connected upstream of the cage stranding machines to unwind a so-called core strand 4 and guide it through the two stranding cages to thus serve as a basis for the stranded layers. In the illustrated embodiment, the stranded material 5 removed from stranding cage 2 is also guided through a device 6 in which a sheath is spun around the stranded material 5. The finish stranded and sheathed material is then removed by way of a double-disc removal device 7 and is wound on drums in a coiler 8.
In the illustrated embodiment, stranding cage 1 is operated at such a number of cage revolutions that, with the given throughput rate, i.e. the removal speed given by removal device 7, a lay length of 250 mm is realized. To realize a perfect, two-layer structure, stranding cage 2 is operated at a somewhat lower number of cage revolutions so that here a lay length of 300 mm results for the second layer. Due to the shorter lay length, stranding cage 1 is operated at a higher number of revolutions so that the speed regulation of this machine determines the production output of the entire system.
Both stranding cages 1 and 2 and spinning device 6 as well as removal device 7 may now be driven either by one drive motor equipped with a mechanical transmission for all machines or, as shown in FIG. 1, by way of individual electrical drive motors at each machine which, however, are positively driven by electronic means at a predetermined, given rpm ratio relative to one another.
Corresponding to the proposed regulating procedure, the system is now designed in such a manner that spool carrier 10 in stranding cage 1 lying closest to stranding rack 9 is provided with a measurement value pickup 12 at the bearing for spool 11 by way of which the centrifugal forces exerted by spool 11 on spool carrier 10 can be measured. The measurement signal is switched to an electronic evaluation system 13, either by way of a transmitter or by way of a slip ring. This electronic evaluation system is in turn connected with the speed regulating devices for the individual drive motors b, c, d and e. Electronic evaluation system 13 is here set to a fixed desired centrifugal force value so that the number of revolutions of the individual drive motors can be varied in a given mutual relationship according to the deviation between the actual centrifugal force value measured by measurement value pickup 12 and the given desired value. Since the spool weight decreases with increasing duration of the stranding job, the speed of all drives must be increased according to the given desired value. Since now the length of the lay for the stranded material is to remain practically constant over its entire length, the speed of advancement of the finish stranded material must accordingly also be increased by appropriately increasing the number of revolutions of drive motor e for removal device 7. Drive f for coiler 8 is regulated in the conventional manner, independently of the drives for the cage stranding machine, as a function of the tension in the stranded material. In contrast thereto, unwinding mechanism 3 is provided only with a brake a for regulating the tension.
Since the second layer applied by way of stranding cage 2 should also be applied with a constant lay length, the number of revolutions of motor c which drives stranding cage 2 must also be increased correspondingly as a function of the given lay length and the removal rate now given by the number of revolutions of motor e of removal device 7. The same applies also for drive d of sheathing device 6.
For example, insulated individual copper conductors having a cross section of 1.5 mm 2 are to be stranded with the illustrated cage stranding system. This results in a gross spool weight of 186 kg. With the given lay length of 250 mm, a desired centrifugal force value of 60,000N is given for stranding cage 1. As shown in FIG. 2, this permits a starting speed of 272 rpm and a removal rate at the beginning of the stranding job of about 68 m per minute for the given lay length of 250 mm. Corresponding to the continuous decrease of material to be stranded on the spool and the resulting reduction in spool mass, the number of cage revolutions can now be increased continuously, as indicated schematically in FIG. 2, so that the maximum number of revolutions of about 380 rpm permitted for the machine is reached after about 50 minutes. This maximum number of revolutions is then used to remove the remainder of the material to be stranded from the spools so that stranding cage 1 can be operated at the maximum number of revolutions for about 15 minutes of the total operating period of about 80 minutes. As a whole, there thus results an average removal rate for the finish stranded material of about 82 m/min. For stranding cage 2, a lower number of cage revolutions results which corresponds to the greater length of the lay.
While, with the described regulation, stranding cage 1 is subjected to a centrifugal force of 60,000N, it would have to absorb a maximum centrifugal force stress of 88,000 N for the same production output without the proposed regulation, i.e. with operation at a constant number of cage revolutions This comparison of numbers itself already indicates that it is possible with the proposed regulating method to considerably reduce the required start-up power, construction costs for all bearings and for the cage brakes.
As shown by the cross-sectional view of FIG. 3, two parallel rows of spools 11 are exchangeably arranged in each stranding cage, one behind the other in the axial direction. For this purpose, the spindle sleeves 15 for the spools are opened in a known manner for the respective upper row and, after the empty spools are taken out, the full spools 11 are inserted by way of a loading device and the spindle sleeves are closed. Once the stranding cage has been rotated about 180° by means of an auxiliary drive, the same loading operation takes place for the second row of spools.
In the region of the spool bearing, the stranding cage is provided with a measurement value pickup 12 for at least one spool. Measurement value pickup 12 may be, for example, a so-called pressure pickup on which a spool bearing is outwardly supported in the radial direction. Such pressure pickups are composed, for example, of a metal body onto which strain gauges are glued in the customary manner. Upon deformation of the body, the electrical resistance of the strain gauge changes in proportion with the deformation and thus in proportion with the deforming force. Instead of strain gauges, piezo-electric systems or other force-measuring systems may also be employed. The direction of the centrifugal force to be measured is indicated by arrow 17 which is oriented perpendicularly to the spool axis.
As shown in FIG. 1, a mechanically or optically acting pickup 16' and 16" may be arranged as an additional measure downstream of one stranding cage to monitor the length of the lay. If there is a deviation of the length of the lay from the given value, an additional regulating action connected in cascade with the regulation on the basis of the centrifugal force can be used for a machine operating with a single layer to regulate the number of revolutions of the drive for removal device 7.
However, in the embodiment of FIG. 1 which involves a machine operating with two layers, this regulating action must be superposed on the regulation of the number of cage revolutions as a function of the centrifugal force since each layer must be regulated independently while the removal rate is regulated by way of the drive for the removal device exclusively as a function of the centrifugal force. Since this superposed regulating action to produce a constant lay length simultaneously influences the centrifugal force measurement, this additional measurement signal must be subtracted with the correct sign from the centrifugal force measurement signal in electronic evaluation system 13, i.e. if the number of cage revolutions is increased slightly in order to regulate the length of the lay, a corresponding, proportional amount must be subtracted from the measured value of the centrifugal force signal so that only a corrected measurement signal acts on the drive of the removal device.
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A stranding machine, and a method for controlling same wherein a measurement device is utilized to measure the centrifugal forces of a spool of the stranding machine. The strand spool rotation rate is then regulated dependent upon the measured centrifugal forces. As the material is depleted from the spool, the spool rotation rate is increased while maintaining a centrifugal force reading within given perimeters.
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BACKGROUND OF THE INVENTION
The present invention relates to an ironing board, and in particular to an ironing board for use in the ironing of clothing garments.
DESCRIPTION OF THE PRIOR ART
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the prior art forms part of the common general knowledge in Australia.
Typically, ironing is achieved by placing a garment to be ironed on a flat surface and urging the garment against the flat surface using a hot iron to thereby cause the garment to be flattened. Normally, ironing is achieved using an ironing board formed from a flat heat resistant board supported parallel to the ground. The garments are laid on the board allowing the garments to be ironed in use.
However, traditional ironing boards suffer from a number of disadvantages. In particular, the garments are usually designed to fit on the human form and accordingly, it is often difficult to lay the body shaped garments flat on the ironing board. Secondly having the ironing board orientated in a horizontal position parallel to the ground can lead to difficulty in ironing some articles, in particular, because of the position in which the iron must be held.
Alternative solutions to the use of an iron and ironing board have been proposed. However, these techniques typically require the use of heated pressing rollers and accordingly, the equipment is usually bulky, expensive and difficult to operate. As a result, such techniques are only of limited use.
SUMMARY OF THE PRESENT INVENTION
In a first broad form the present invention provides an ironing board including:
a) A support; and, b) An ironing surface having a substantially convex shape, the ironing surface being movably mounted to the support to allow the ironing surface to be moved between first and second substantially perpendicular ironing positions.
The support is adapted to support the ironing surface above the ground in use. In this case, the ironing surface is typically substantially parallel to the ground in the first ironing position, and substantially perpendicular to the ground in the second ironing position.
The ironing surface is normally formed from the surface of an ironing member having a substantially oval cross section.
The ironing member typically defines an ironing axis, with the ironing member preferably being coupled to the support so as to allow rotation of the ironing member about the ironing axis.
Similarly, the support typically defines a support axis, with the ironing member preferably being coupled to the support so as to allow rotation of the ironing member about the support axis.
Optionally, the support includes a vacuum means and the ironing member includes a number of apertures defining flow paths extending from the ironing surface to the vacuum means, wherein in use, the vacuum means is adapted to draw air along the flow paths thereby urging garments against the ironing surface in use.
The support preferably includes a steam generator for generating high pressure steam.
In this case, the ironing board usually includes a hose for coupling to the steam generator, the hose defining a flow path to allow the steam to be directed onto garments positioned on the ironing member in use. Alternatively, or additionally the steam generator can be coupled to the flow paths so as to allow steam to be provided directly at the ironing surface.
The ironing surface may optionally include a number of fastenings adapted to fasten garments in a desired position in use.
The support may include a power supply for supplying power to an iron in use.
The end portion of the ironing surface may be optionally shaped like the top portion of a human torso wherein the end portion is preferably detachably coupled to the ironing surface.
BRIEF DESCRIPTION OF THE DRAWINGS
An example of the present invention will now be described with reference to the accompanying drawings, in which:
FIG. 1 is a schematic perspective view of a first example of an ironing board according to the present invention;
FIG. 2 is a schematic perspective view of a second example of an ironing board according to the present invention;
FIGS. 3A , 3 B, 3 C are schematic front, side and top views of the support of FIG. 2 ; and,
FIGS. 4A and 4B are schematic views of a third example of an ironing board according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An example of an ironing board according to the present invention is shown in FIG. 1 .
As shown in FIG. 1 , the ironing board is formed from a support member 1 and an ironing member 2 coupled together via a joint 3 . The ironing member is formed from heat resistant material allowing garments to be placed on the ironing member and ironed in use.
As shown, the ironing member 2 has a substantially oval cross-sectional shape such that the ironing surface provided by the ironing member is curved. As a result, when garments are positioned on the ironing member the garments, which are also typically curved to fit the shape of the human body, tend to conform to the shape of the surface of the ironing member more easily than would be the case if the surface were flat. It will be appreciated that this effect is enhanced if the ironing member 2 has dimensions similar to those of the human torso.
The joint 3 is adapted to allow the ironing member 2 to be moved between the position shown at 2 A, in which the ironing member is substantially horizontal, and the position shown at 2 B, in which the ironing member 2 is substantially vertical. This therefore provides the user with at least 2 different ironing positions.
In addition to this, the joint 3 also allows the ironing member 2 to be rotated about a first axis 4 , that extends from the joint 3 to the base of the support 1 , and a second axis 5 , that extends from the joint 3 along the ironing member 2 . Accordingly, this allows the ironing member 2 to be rotated, as well as to be swivelled about the support 1 , thereby allowing the ironing member 2 to take on a number of different orientations, as will be appreciated by a person skilled in the art.
Accordingly, when garments are positioned on the ironing member 2 in use, the ironing member 2 can be moved between the first and second positions 2 A, 2 B to allow the user to iron in the conventional orientation as well as in a vertical orientation, which is of particular use for example when ironing shirts, skirts or the like which can be positioned.
In addition to this, the ironing member 2 can be rotated around either one of the axes 4 , 5 to allow the user access to the other side of the garment.
Accordingly, by providing an ironing surface that can be reorientated in this manner, this allows users to iron an entire garment without having to remove the garment form, or reposition the garment on, the ironing member 2 .
The support 1 is also usually provided with wheels 6 , as shown to allow the ironing board to be easily moved without requiring the full weight of the board to be lifted.
A second example of an ironing board according to the invention is shown in FIG. 2 . In this example, only the position 2 A of the ironing member is shown for clarity. In this example, the ironing board includes a vacuum system and a steam system, as will now be described.
The vacuum system is formed from a vacuum pump 8 , coupled via a flow path 9 , which extends through the joint 3 , to a number of apertures 10 , formed in the surface of the ironing member 2 . In use, when the vacuum pump is activated air is drawn in along the flow path 9 via the apertures 10 . Accordingly, when a garment is placed on the ironing member, the sucking action of the vacuum pump causes the garment to be urged against the ironing surface in use. This helps ensure that the garment is retained in position flat against the ironing surface, in use. In addition to this, if the garment is being steamed, the vacuum system helps draw the steam through the garment, thereby aiding the action of the steam, as well as reducing the time taken for the garment to dry. It should be appreciated that any means which provides that air flows into the apertures 10 of the ironing surface, thereby providing a sucking action, may be used in said vacuum system, such as for example a fan.
In addition to this, a steam generator 11 may also be provided. In this case, the steam generator 11 may also be coupled to the flow path 9 to allow steam to be transferred to the garment via the apertures 10 . It will be appreciated that in this case, because the steam generator 11 is operate to steam the garments via the apertures 10 , then the vacuum system cannot be used.
This can be overcome in two ways. Firstly, an alternative flow path 9 and separate set of apertures 10 could be provided for each of the vacuum system and the steam system.
Secondly, the steam generator 11 can also be coupled to an external hose shown schematically at 12 . In this case, the steam generated by the steam generator is output via the hose 12 . This allows the user to hold the hose 12 so as direct steam onto the garment in use as required.
It will be appreciated that the steam generated by the steam generator 10 can also be used to provide high pressure steam that can be used for cleaning purposes, such as cleaning kitchen dirt including lime deposits, coffee stains, grease or the like, as well as cleaning curtains or other fabrics.
Controls for controlling the vacuum pump 8 and the steam generator 11 are provided as shown generally at 3 , in FIGS. 2 , 3 A, 3 B and 3 C.
The support 1 can also incorporate a power supply 14 to supply power to the iron in use. The allows the support 1 to be wired to an electrical supply, such as mains electricity, and then have the iron plugged into the support 1 . This helps prevent the user having to arrange the ironing board in a particular orientation to allow the irons power supply cord to reach an electrical socket.
As an additional feature, the ironing member 2 may be provided with fastenings, such as clips (not shown) to allow the garments to be fastened to the ironing member in use. This allows the user to stretch the garments securely to make difficult tasks such as creating pleats on items easier.
Furthermore, it will be appreciated that the joint 3 may be adapted to allow the ironing member 2 to be orientated at any orientation between the positions shown at 2 A, 2 B.
A further example of an ironing board according to the present invention is shown in FIGS. 4A and 4B . In this embodiment, the support member 20 is in the form of a more compact design coupled to a substantially planar base plate 25 which provides added stability to the ironing board. The support member 20 includes a panel 26 which is pivoted at point 27 and moveable between a closed position (shown in FIG. 4A ) and an opened position (shown in FIG. 4B ) providing easy access to the interior of the support member 20 which may include a water tank 28 , boiler 29 and/or electronic components 30 . A water gauge 31 may be fitted in connection with the water tank 28 in order to provide a visual indication of the level of water contained in said water tank 28 when the panel 26 is in the closed position.
The ironing member 21 is shown in a first position in 4 A, in which the ironing member 21 is substantially vertical, and the position shown in 4 B, in which the ironing member 21 is substantially horizontal position, providing a user with at least two different ironing positions. It will be appreciated however, that the joint 22 may be adapted to allow the ironing member 21 to be orientated and fixed at any orientation between the positions shown in FIGS. 4A and 4B .
A shirt attachment 23 is depicted in FIG. 4A , the shirt attachment 23 being similar in shape to the top portion of a human torso. This shirt attachment may be detachably coupled to the end portion of the ironing member to aid in the ironing of shirts and/or upper body garments.
Finally a power supply point 32 and/or steam supply point 33 may be located on the support member 20 for easy accessibility by an ironing handpiece.
Persons skilled in the art will appreciate that numerous variations and modifications will become apparent. All such variations and modifications which become apparent to persons skilled in the art, should be considered to fall within the spirit and scope that the invention broadly appearing before described.
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An ironing board including a support ( 1 ); and, an ironing surface ( 2 ) having a substantially convex shape, the ironing surface ( 2 ) being movably mounted to the support ( 1 ) to allow the ironing surface ( 2 ) to be moved between first ( 2 A) and second ( 2 B) substantially perpendicular ironing positions.
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BACKGROUND OF THE INVENTION
This invention relates to aiding people who have difficulty elevating themselves from one level to another, as for example stepping up into and down from a van, or climbing on to an examination table in a doctor's office or hospital. More particularly my invention relates to portable steps that have handrails and are easily stowable. The handrails on prior foldable steps did not provide adequate support for handicapped or elderly people. Also, when folded, the prior steps took up too much space or had projecting components or irregular outer surfaces that made it difficult to store the folded steps in a confined space.
OBJECTIVES OF THE INVENTION
Accordingly, it is an object of this invention to provide improved foldable steps with sturdy ergonomically designed handrails that inspire confidence in people that have difficulty stepping up or down.
Another object is to produce portable steps that fold inside of their integral handrails so as to provide a relatively smooth exterior surface that has no jagged edges or protruding parts so that the folded steps are stowable in relatively narrow confined spaces.
An additional object is to provide foldable steps having handrails that have flat outer surfaces when folded so that the folded steps will lie flat in an vehicle and can have other objects stored on top of them, and the flat outer surfaces of the folded steps also allow them to be easily stored against a flat wall surface or between the flat surfaces of furniture or cabinets.
Another object is to provide foldable steps that present a relatively continuous, firm, substantial supporting surface upon which relatively heavy objects can be safely stored when the steps are folded.
Another object is to provide foldable steps with relatively smooth outer surfaces that will not mar the surfaces of things that the folded steps are slid on or against or stored on, under or against.
A further object is to provide compact, portable, easily stored folding steps that have substantial handrails and are relatively light weight, durable, economical, attractive, easy to use and maintain, and which do not possess defects found in similar prior art folding steps.
Other objects and advantages of the folding steps incorporating my invention will be found in the specification and claims and the scope of the invention will be set forth in the claims.
DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of an embodiment of foldable steps in accord with this invention, showing the steps in their fully open position.
FIG. 2 is a perspective partially broken away view of the foldable steps, showing the steps in their partially open position.
FIG. 3 is a perspective view of the foldable steps, showing the steps in their fully closed position.
FIG. 4 is an enlarged, schematic, cross sectional view taken generally along the line 4 — 4 in FIG. 3 .
FIG. 5 is a top plan view of the steps in their fully closed position.
FIG. 6 is a partially broken away, schematic, side view showing the steps in their open position.
FIG. 7 is a cross sectional view taken along the line 7 — 7 in FIG. 6 .
FIG. 8 is a cross sectional view taken along the line 8 — 8 in FIG. 6 .
DESCRIPTION OF THE INVENTION
The drawing shows a compact, portable, folding climbing aid 10 in accord with my invention, that may be made from strong lightweight plastic or metal, such as aluminum or titanium. The aid 10 has a first fully open expanded position, as shown in FIGS. 1 and 6 – 8 , and a second closed or folded position, as shown in FIGS. 3–5 .
Aid 10 has a first upper step 11 that is located above a second lower step 12 when the aid 10 is in its open position. The step 11 has a front edge 14 , a rear edge 15 , one side edge 16 , an opposite side edge 17 , and a flat tread surface 18 . As shown in FIGS. 2 , 7 and 8 , front edge 14 has an attached pivoting end 19 and an unattached free end 20 , and rear edge 15 has an attached pivoting end 21 and an unattached free end 22 . The step 12 has a front edge 23 , a rear edge 24 , one side edge 25 , an opposite side edge 26 , and a flat tread surface 27 . As shown in FIGS. 2 , 6 an 8 , front edge 23 has an attached pivoting end 28 and an unattached free end 29 , and rear edge 24 has an attached pivoting end 30 and an unattached free end 31 . The front edge 14 of step 11 has an integral flange 32 and the rear edge 15 has an integral flange 33 extending therefrom. The front edge 23 of step 12 has an integral flange 34 and the rear edge 24 has an integral flange 35 extending therefrom. The side edges of the steps also may have integral flanges extending therefrom. The flanges 32 , 33 , 34 , and 35 each have a notch, respectively 36 , 37 , 38 and 39 , adjacent their free unattached end.
The aid 10 has a first handrail 40 and an essentially identical second hand rail 41 . Handrail 40 has a first leg 42 of predetermined length, a second leg 43 of lesser length, an integral slanting hand grip bar 44 connecting its legs, and an outwardly facing generally flat exterior surface 45 . Handrail 41 has a first leg 46 of predetermined length, a second leg 47 of lesser length, an integral slanting hand grip bar 48 connecting its legs, and an outwardly facing generally flat exterior surface 49 . The handrails 40 and 41 are generally square in cross section with chamfered corners. When in the aid 10 is in its expanded position, the steps 11 and 12 are horizontal and the handrails 40 and 41 are separated at the opposed side edges 16 and 17 and 25 and 26 , respectively, for easy gripping by a person stepping up or down on the steps.
A first flat panel beam 55 connects the legs 42 and 43 of handrail 40 and spans the distance separating these legs. Beam 55 has a flat, smooth, outwardly facing exterior surface 56 that is aligned in the same plane with the flat exterior surface 45 of handrail 40 . A second flat panel beam 57 connects the legs 46 and 47 of handrail 41 and spans the distance separating these legs. Beam 57 has a flat, smooth, outwardly facing exterior surface 58 that is aligned in the same plane with the flat exterior surface 49 of handrail 41 . A slight clearance space 59 separates the beams and steps.
A first integral post 60 is attached to first beam 55 and extends above beam 55 . A second integral post 61 is attached to second beam 57 and extends above beam 57 . The attached end 30 of the rear edge 15 of step 11 is pivotally connected at 62 to leg 42 above beam 55 . The attached end 29 of the front edge 14 of step 11 is pivotally connected at 63 to post 60 above beam 55 . The attached end 31 of the front edge 23 of step 27 is pivotally connected at 64 to the leg 43 of handrail 40 . The attached end 31 of the rear edge 24 of step 12 is pivotally connected at 65 to post 60 intermediate the ends of post 60 .
A first hollow cylindrical sleeve bushing 70 extends from an interior surface of the leg 46 toward the leg 47 above the beam 57 . A second hollow cylindrical sleeve bushing 71 extends from an inner surface of the leg 47 toward the leg 46 below the step 18 . A third hollow cylindrical sleeve bushing 72 extends from the second post 61 and is diametrically aligned with the bushing 70 . A fourth hollow cylindrical sleeve bushing 73 extends from the second post 61 and is diametrically aligned with the bushing 71 . The bushings 70 and 71 are secured in place by bolts that pass therethrough and are threaded into rivetnuts in the designated legs. The bushings 72 and 73 are held on the posts 60 and 61 by bolts that pass therethrough and are threaded into nuts. When the aid 10 is in its fully extended position, the unattached free end 22 of edge 15 of the step 18 is supported on the bushing 70 which is received in the notch 37 , the unattached free end 20 of edge 14 of the step 18 is supported on the bushing 72 which is received in the notch 36 , the unattached free end 31 of edge 24 of the step 27 is supported on the bushing 73 which is received in the notch 39 , and the unattached free end 29 of edge 23 of the step 27 is supported on the bushing 71 which is received in the notch 38 .
A first pivoting link 77 is pivotally connected at one end 78 to the outer side of a first rectangular prismatic support block 79 that is attached by bolts or welding (not shown) at a central location on the underside of step 11 adjacent to its rear edge 15 . The opposite end 80 of link 77 is pivotally attached to leg 46 adjacent the terminal end of the leg. A second pivoting link 81 is pivotally attached at one end 82 to a central portion of the flange 35 at the rear edge 24 of step 12 and at its opposite end 83 to a central portion of the flange 32 at the front edge 14 of step 11 . An integral tab 84 extends perpendicularly to link 81 toward step 11 . When the aid 10 is in its fully closed position, the tab 84 will bind against the edge 14 and prevent the step 12 from moving out of alignment past the step 18 .
A third pivoting link 88 is pivotally attached at one end 89 to the outer side of a second rectangular prismatic support block 85 that is attached by bolts or welding (not shown) at a central location on the underside of step 11 adjacent to its front edge 14 . The opposite end 90 of link 88 is pivotally attached to the post 61 below the bushing 73 . A first articulated pivoting link 91 has a long segment 92 and a short segment 93 that are pivotally connected to each other at one end at 94 . The opposite end 95 of the long segment 92 is pivotally attached to the leg 42 adjacent its terminal end. The long segment 92 of the first articulated link 91 and the link 71 are pivotally connected to each other at 96 intermediate their ends. The opposite end 97 of the short segment 93 is pivotally connected to the bushing 70 . A second pivoting articulated link 98 has a long segment 99 and a short segment 101 that are pivotally connected to each other at one end at 102 . The opposite end 103 of the long segment 99 is pivotally attached adjacent the bottom end of the first post 60 . The long segment 99 and the third link 88 are pivotally connected to each other at 104 intermediate their ends. The opposite end 105 of the short segment 101 is pivotally connected to the third bushing 72 .
A cylindrical stabilizer bar 106 has its opposite ends attached to the inner side of block 79 and the inner side of block 85 below step 11 . The effect of bar 106 is to interconnect the links 77 , 81 , 91 and 98 . This enables the bar to stabilize the aid 10 by preventing misalignment or wobbling of the links or steps.
When the aid 10 is in its folded position, as shown in FIGS. 4 and 5 , all of the pivoting links, the bushings and the steps and the beams are confined within the inner edges or boundaries of the handrails 40 and 41 . There are no protruding bulges or sharp corners or edges that can mar other objects. The flat tread step surfaces 18 and 27 , the flat exterior beam surfaces 56 and 58 , and the flat exterior handrail surface 45 can all be aligned in the same plane. As shown in FIG. 3 , these aligned planar surfaces occupy at least about 80% of the space circumscribed by the handrails. This relatively large, essentially continuous flat surface within the handrails enables the folded aid 10 to be easily slid on, against or between other flat or uneven surfaces for storing. This flat surface also is available as a firm horizontal supporting surface for holding or stacking heavy objects when the aid 10 is laid out horizontally.
While the present invention has been described with reference to particular embodiments, it is not intended to illustrate or describe all of the equivalent forms or ramifications thereof. Also, the words used are words of description rather than limitation, and various changes may be made without departing from the spirit or scope of the invention disclosed herein. It is intended that the appended claims cover all such changes as fall within the true spirit and scope of the invention.
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A climbing aid for assisting people to move up or down to different levels has steps that can be folded into attached integral handrails that circumscribe the steps when folded so that no parts extend outside of the boundaries of the handrails.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a national phase application under 35 U.S.C. § 371 of PCT international application No. U.S.2004/022262, filed Jul. 12, 2004, which claims the benefit of U.S. Provisional Application 60/486,037, filed Jul. 10, 2003, which is incorporated by reference herein.
TECHNICAL FIELD
The present invention relates to yarn filament configuration, yarn fiber combination, yarn spinning techniques, and ecologically friendly and functionally sustainable textile design solutions.
BACKGROUND OF THE INVENTION
The present invention may be understood in light of the following state of the art.
Ever since processes of converting crushed plastic bottles made of polyethylene terephthalate (PET) into fiber for textiles was proposed as a substitute for virgin polyester, attempts have been made to commercialize the processes. However, development of filaments, staple fiber, yarn, and fabric for the purposes of expanding the potential end uses of these fibers has been relatively limited. This has been attributed primarily to the inherently high cost of acquiring a clean raw material source. When one uses polymer made from the inherently impure post consumer recycled (PCR) polyethylene terephthalate (PCR-PET), one is limited to staple spun yarn rather than a continuous filament yarn because of the unpredictable weak points in monofilaments caused by the impurities. Practical uses for the staple spun yarn have been limited.
When particular domestic-based end use product manufacturers brought products containing fabric made from recycled plastic bottles to market and charged a premium for a product that had inherent quality deficiencies, they were unable to sustain significant enough market demand for these products to merit the expansion of plastic bottle fiber production. Instead, the fiber mills, which had originally predicted growth In market consumption of the fiber, were forced to close fiber plants that were originally supplying these domestic-based end use product manufacturers with their fiber.
Therefore, a longstanding need has existed for an economical method of utilizing PCR-PET to manufacture useable yarn of high quality.
Several highly cost-intensive PCR-PET purification methods now exist which are able to almost eradicate contamination from the recycled materials stream. They produce food-grade materials, and such materials might be suitable for producing continuous filament yarn. Because of their cost, however, they are not presently useful for producing commercially viable fiber.
The manufacture of yarn, whether in the form of thread or higher denier yarns, is one of the oldest technologies known. Numerous manufacturing methods are known for making continuous filament yarns, for combining continuous filaments into yarns, and for making yarns from shorter, staple fibers. Spinning staples into yarns has been known since prehistory.
Today, the three most popular spinning frames for staple spun yarn are ringspun, open end, and air jet. Prior to air jet, ringspun was considered the best in terms of quality and strength. Open end spinning has always been considered to be cheap and fast. Air jet is now hailed by most industry experts to be the optimal type of spinning frame for almost any application. Air jet spinning produces a fasciated yarn including a sheath of generally axially aligned staples bound together with discontinuous generally helical bundles of staples. Air jet machines are expensive; however their output speeds even at fine counts make them the best solution from an economic standpoint. From the standpoint of performance, the air jet produces the lowest pill yarn ever spun. The only complaint thus far is that the strength of an air jet yarn is slightly less than the strength of a ringspun yarn; however, this issue is easily overcome by placing a filament core inside the air jet yarn. The general rule for staple fiber going into air jet spinning frames is that it should be between about 1.2 and 2.0 inches (3 to 5 cm) in length, preferably between about 1.2 and 1.7 inches (3 to 4.3 cm) in length, and most preferably about 1.5 inches (3.8 cm) in length. Diameter of the staples can range from about 0.5 to about 2.0 denier per filament (dpf). A variant of an air jet spinning frame is known as a vortex spinning frame. A vortex spinning frame is capable of spinning a wider range of natural staple fibers, including cotton fibers, than is easily obtained with the earlier forms of air jet spinning frames. The vortex spinning frame produces a three-dimensional cotton sheath having better hand than does the basic air jet frame. It is also faster.
Air jet spinning frames are well known in the art. Air jet spinning is presently dominated by Murata Kikal KK of Kyoto, Japan. Its MJS air jet spinning machine, MTS twin spinning machine, and MVS vortex spinning machines are widely used and their details are known to those skilled in the art. Such machines are described for example in Oxenham, “Fasciated Yarns—A Revolutionary Development?” Journal of Textile and Apparel, Technology and Management, Vol. 1, issue 2, Winter 2001, pp. 1-7; Oxenham, “Developments In Spinning,” TextileWorld.com, May 2003; and in numerous patents, such as Shaikh et al., U.S. Pat. No. 6,405,519 ; Scheerer et al, U.S. Pat. No. 6,250,060; Scheerer et al., U.S. Pat. No. 5,960,621; Ota, U.S. Pat. No. 5,481,863; Griesshammer et al., U.S. Pat. No. 6,679,043; Shigeyarni et al., U.S. Pat. No. 6,655,122; and Mori, U.S. Pat. No. 6,370,858.
Other yarns include those in which a core is covered with a continuous filament helix using a covering machine (sometimes called coverwrapping machine or wrapping machine). These machines are traditionally used to cover spandex or other continuous filament stretch yarns. A single or double helix is applied by a standard covering machine. Covering machines are occasionally used to cover non-stretch continuous filament cores to produce “fancy” yarns for small niche markets or industrial yarns. Such machines are sold by a number of manufacturers, for example by Rieter/ICBT, now known as the Filament Yarn Technologies Group, of Rieter Machine Works, Ltd., Winterthur, Switzerland. They are also widely described in the patent literature, for example in Siracusano, U.S. Pat. No. 4,350,731; Tillman, U.S. Pat. No. 4,137,698; and Payen, U.S. Pat. No. 4,525,992.
Continuous filament yarns are sometimes texturized (also called textured) by a texturizing machine to give them particular surface or geometrical properties. For example, a filament may be given a “false twist” by twisting it, heating it, cooling it, and then untwisting it, or it may be given a more random shape by the several high-speed air methods described in Bertsch et al., U.S. Pat. No. 6,088,892. l Surface features are given by other methods, known to those skilled in the art. Generally, texturizing yarn filaments is done for the purpose of giving a synthetic (plastic) yarn some of the characteristics of a natural fiber.
Synthetic yarns are generally superior to yarns made of natural fibers in tenacity (tensile strength), abrasion resistance, quick-drying properties, and dimensional stability, but they generally lack the hand, drape, and moisture absorbance of their natural fiber counterparts. It is frequently desirable to produce yarns having special characteristics such as fire retardancy, high moisture permeability, bacterial resistance, ultraviolet ray resistance, low surface friction, or special aesthetic texturing. Generally, providing one of these characteristics requires compromising other characteristics of a synthetic or natural yarn. For example, high tenacity synthetics such as polyarnides including aromatic polyarnides (aramids) and high-tenacity aliphatic polyarnides (nylon), carbon, or glass provide much higher tenacities than many other synthetics or most natural fibers, but they lack many desirable characteristics as a yarn for numerous fabrics. Aramids provide greater tenacity than high-tenacity nylons, but they are susceptible to ultraviolet radiation. Providing other characteristics in a high-tenacity synthetic yarn generally reduces the tenacity of the yarn.
SUMMARY OF THE INVENTION
The present invention produces enhanced performance yarns which comprise, and are functional and economic alternatives to, 100 % petroleum oil based virgin continuous filament yarns, such as polyesters (like virgin polyethylene terephthalate), polyarnides (like nylon and aramids), polyolefins (like polypropylene and polyisobutylene), fluorocarbons (like polytetrafluoroethylene), high tenacity nylon, high tenacity polyester, and yarns formed of regenerated natural materials (like rayon and acetate). A list of man-made fibers, all of which are to some extent useable with embodiments of the present invention is contained in ISO Standard 2076: 1999(E) and in United States 16 Code of Federal Regulations part 303, particularly §303.7 (Dec. 1, 2000), both incorporated by reference. The invention also produces enhanced performance yarns which comprise, and are functional and economic alternatives to, natural spun vegetable yarns (like cotton, linen, hemp, jute, and bamboo), silk yarns, and wool and other animal fiber yarns. These yarns are achieved by way of new yarn filament configurations and yarn manufacturing methods which, among other things, provide a sustainable avenue to incorporate highly significant amounts of recycled plastics, particularly post consumer recycled (PCR) thermoplastic material such as polyethylene terephthalate (PET), which contains medium to high levels of contamination, into a yarn without sacrificing many if any of the performance characteristics or properties that are inherent to the related competing alternate yarn type. The alternate yarn type may be, for example, 100% petroleum oil based virgin continuous filament yarn or may be natural or synthetic staple spun yarn.
Corespun yarns with a continuous filament core, a spun sheath of recycled thermoplastic such as PCR-PET, and a spun cover formed either with an air jet (Including vortex Jet) machine or a cover wrapping machine are particularly advantageous. Other yarns and methods of making them also fall within the purview of the present invention, as will be understood by those skilled in the art in light of the following description, drawings, and claims.
Only post consumer recycled polyethylene terephthalate (PCR-PET) which in its pre-extruded liquid form contains substantial enough levels of contamination to prevent it from remaining in a continuous filament at post extrusion due to the unpredictable points of weakness caused by the inherent impurities contained within the polymer, is economically logical for use in a staple form.
in present economic conditions, the cleanest PCR-PET pre-extruded liquid polymer that this invention is appropriate for accommodating can not run through a filament extrusion hole smaller than seventeen to twenty microns. Another way of stating this is that a suitable pre-extruded liquid PCR-PET, in a standard pressure drop test, requires a pressure of greater than about 100 pounds per square inch (psi) for a twenty micron opening in order to be economically viable. Typically, the pressure drop of suitable pre-extruded PCR-PET will be about 500 psi or less for use in an extruder having a 20 micron opening and producing a 1.2 dpf staple. If the liquid polymer is pure enough to economically run through an extrusion hole smaller than seventeen microns in a manufacturing operation, then it is likely to have a more appropriate use elsewhere than in producing staple fiber, even staple fiber for use in the present invention. Larger diameter staple, extruded through a larger hole, may be used with other spinning methods.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a standard commercially available air jet spinning machine for use in performing steps of preferred embodiments of the present method.
FIG. 2 is a view in side elevation, partially cut away, of the yarn produced by the machine of FIG. 1 .
FIG. 3 is a schematic view of standard commercially available machine for winding a covering thread around a core.
FIG. 4 is a view in side elevation, partially cut away, of a yarn of this invention produced from the yarn of FIG. 2 by the machine of FIG. 3 .
FIG. 5 is a schematic view of a standard commercially available air jet spinning machine modified for use in performing steps of preferred embodiments of the present method.
FIG. 6 is a somewhat schematic detailed view of part of the machine of FIG. 5 , showing two types of sliver emerging from an outlet of a T-trumpet portion of the machine and being formed into a yarn of this invention.
FIG. 7 is a view in side elevation, partially cut away, of a yarn of this invention produced by the machine of FIGS. 5 and 6 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The embodiments of the present invention described below are not meant to be limiting of the invention but to illustrate presently preferred embodiments.
EXAMPLE 1
Preparation of an Intermediate Yarn
Referring now to the drawings, and in particular to FIGS. 1 and 2 , a preferred form of an intermediate yarn 1 for use in some illustrative preferred embodiments of the present invention is produced on a standard Murata MJS or MVS spinning frame 3 . The spinning frame 3 , as is well known in the art, includes a sliver supply 5 which feeds sliver through a trumpet 7 , into a drafting zone. Sliver is staple which is processed by a carding machine into a solid controllable and soft form. The drafting zone comprises a pair of back rolls 9 , a pair of middle rolls 11 , a pair of apron rolls 13 , and a pair of front rolls 15 . If desired, a guide or condenser may be included between the back rolls 9 and middle rolls 11 .
As shown in FIG. 1 , the spinning frame 3 is set up with a standard core attachment for inclusion of a core. A continuous filament core yarn 17 is fed through a pigtail guide 19 into the spinning frame at the forward end of the drafting zone, at front rolls 15 .
The front rolls 15 feed the core yarn 17 and drafted sliver into a spinning zone comprising spinning nozzles 21 and delivery rolls 23 which form the sliver into a spun sheath surrounding and hiding the core yarn 17 in accordance with well-known principles.
The completed corespun yarn 1 is passed through a yarn clearer 25 and rolled onto a core package 27 .
The corespun yarn 1 which forms an intermediate yarn for use in the present invention is shown in FIG. 2 . In this illustrative embodiment, the sliver 5 , hence the spun sheath 5 of the yarn 1 is formed of PCR-PET having a staple length of about 1.5 inches (3.8 cm) and a diameter of about 0.7 to 2 denier. The PCR-PET is cleaned sufficiently to be suitable for the formation of staple fibers but not continuous filament. The continuous filament core is illustratively formed of a high tenacity multifilament bundle, illustratively high tenacity nylon having a tenacity rating of about fifteen. The functions of the core and sheath will be discussed hereinafter in connection with particular constructions of the invention utilizing this intermediate yarn 1 .
EXAMPLE 2
Production of a Wrapped PCR-PET Yarn
As shown in FIG. 3 , a standard coverwrapping machine 31 , modified for use with the intermediate corespun yarn 1 , is used for this step. The coverwrapping machine is illustratively a Model G-307-UE covering machine sold by Rieter/ICBT (Filament Yarn Technologies Group, Rieter Machine Works, Ltd.). The machine is adjusted to accept the intermediate corespun yarn 1 , which differs in construction and physical properties from the usual elastomer (spandex) core fed into the machine. The intermediate yarn 1 is placed on the supply rolls 33 of the covering machine 31 , from which it is fed to a first covering station 35 which applies an inner helix of an inner cover yarn, then to a second covering station 37 which applies an outer helix of an outer cover yarn, wrapped in a direction opposite the first helix. The completed yarn of this embodiment is then rolled on takeup rolls 39 . The outer helix forms the outer cover, which is the surface of the completed yarn.
As shown in FIG. 4 , the completed yarn 41 includes a double helix composed of two continuous filament yarns, an inner helix yarn 43 and an outer helix yarn 45 , which together form a cover that wraps around the outside of the sheath of the corespun yarn 1 .
The continuous filament core 17 acts as a central load bearing point for the entire yarn. In other embodiments of this construction, the filament type of the core 17 can be stretch, high tenacity or standard polymer. The presently preferred core material is high tenacity nylon or polyester, a combination of the two, or a combination of one of the two fiber types with another high tenacity or standard continuous filament yarn possessing a grams per denier tenacity rating between 8 and 35. To date, the optimal core judged from the standpoint of achieving a high strength without generating a high cost, is a high tenacity polyester or high tenacity nylon continuous filament. The core can compose anywhere from 10% to 50% of the total weight of the finished yarn. However, the optimal percentage of the core when using high tenacity nylon or high tenacity polyester, is presently believed to be between 10% and 20%.
The sheath 5 has two main functions, the first being its inherent ability to be a highly compressible component in the yarn, and the second being a sustainable avenue for incorporating a recycled material component in the yarn without affecting the yarn's performance properties.
The sheath is illustratively composed of post consumer recycled polyethylene terephthalate (PCR-PET) staple length fiber. The optimal cut staple length is 1.5-3.0 inches, and the optimal staple dpf (denier per filament) ranges between 0.8 and 3.0 depending on the amount of fibers per cross-section required by the yarn's thickness.
The double helix has two main functions. The first is to provide a surface layer for the yarn having desired aesthetic characteristics and functional characteristics. The second is to interact mechanically with the core and sheath to provide surprising physical characteristics to the completed composite yarn.
In the illustrative embodiment of yarn, the main functions of the double helix is to give the yarn extremely high resistance to abrasion, protecting the inherently less abrasion resistant sheath 5 . Either high tenacity or standard tenacity nylon is recommended because of its traditionally high abrasion resistance properties. It will be seen that the yarn type of the wrap yarns 43 and 45 can be customized to accommodate the special needs of a particular end use application. When the yarn 41 , or a fabric formed from it, needs to have special properties such as fire retardancy, high moisture permeability, bacterial resistance, ultraviolet ray resistance, low surface friction, or special aesthetic texturing, a continuous filament yarn containing any of these mentioned special properties can be selected as the “wrap yarn” to best suit the needs of the yarn end use application. Depending on several variables, different or the same type of continuous filament or spun yarn can be used as the inner and or outer layer helix. Also, the amount of Individual filaments of which the wrap yarn is composed can play a large role in the cover's aesthetic, handling, and physical characteristics. Therefore, for end use applications in which abrasion resistance is paramount, it is best to use a wrap yarn with as few individual filaments as possible. It is even recommended to use a monofilament, so that the entire wrap yarn is composed of one filament. However, when the amount of total individual filaments in the yarn is limited, the yarn and fabric become progressively more rigid as fewer filaments are used in the wrap yarns.
The second function of the double helical cover is to participate in a physical relationship with the core and sheath to provide unexpected physical characteristics, particularly unexpectedly high tenacity.
Although not wishing to be bound by theory, I believe that the double helix wrapped corespun yarn combines the known physics concepts of compression and expansion to form an otherwise unexplainably strong strand of yarn. The standard logic in yarn manufacturing suggests that a high tenacity continuous filament yarn equaling the same diameter as the yarn of this example would be stronger because the yarn of this example is illustratively composed of 17% high tenacity continuous filament core, 43% inherently weaker standard-tenacity polyester staple sheath (PCR-PET), and 40% standard or high tenacity continuous filament yarn which forms the double helix. However, testing of a fabric of this example compared to a 100% high tenacity nylon continuous filament fabric of the equivalent denier proved the new yarn to have higher tenacity than the control fabric.
My interpretation of the interaction of the core, the sheath, and the cover is as follows.
A) The sheath made from staple length fibers is inherently lofty because the structure of a sheath consists of many small fibers spun together which creates tiny air pockets in-between the staples. One way to potentially increase the amount of sheath loft is to use a hollow staple fiber in the sheath; however this could potentially add cost and depending on the degree in which the hollow staple increases the overall strength of the yarn, it may or may not be of great value. Nevertheless, the use of a hollow staple fiber may achieve an even higher tenacity strength rated yarn.
B) The double helix is applied through a mechanical wrapping machine which wraps the two continuous filament wrap yarns tightly around the sheath simultaneously in opposite directions. When the helix yarns wrap, they compress the sheath, and in doing so push out all the air trapped between individual staple fibers. The act of compression alters the original shape and orientation of the sheath's internal structure, in turn forcing the sheath to inherently and continuously attempt to expand. In the sheath's effort to expand, it is consistently applying equivalent amounts of pressure to both the core and the helix. This distribution of pressure compounds the originally separate elements of core, sheath and double helix into one unified strand which has exceptional strength. A fabric composed of yarn made in accordance with this embodiment of the invention has now been tested to have 30% higher grams per denier tenacity levels than a similar fabric made of 100% high tenacity nylon continuous filament of the equivalent denier.
The turns per inch (TPI) is a measure of the density of the cover or double helix within one inch of the yarn. The TPI can greatly affect the degree of abrasion resistance generated by the double helix, and can also greatly affect the degree of grams per denier tenacity rating of the yarn. TPI can be converted into what is known as coverage percentage, meaning the percentage of the surface being wrapped that is covered by the wrap yarns. Higher wrap coverage percentages equal higher yarn abrasion resistance and higher yarn tenacity ratings. They also equal longer processing time and higher cost. Optimal double helix wrap coverage is between 70% and 100%.
EXAMPLE 3
First Alternative Yarn Construction
This construction and the construction of the following Example comprise a high tenacity, standard tenacity, or stretch continuous filament yarn core and a uniquely formed sheath. The sheath comprises two layers of distinctly different staple fiber types. The layers are constructed such that there is an inner layer which touches the core, and an outer layer which is essentially the yarn's exterior surface area. The inner sheath comprises PCR-PET staple length fiber. The outer sheath layer comprises an interchangeable and customizable staple fiber which has specific performance or aesthetic properties or attributes required by the end use application of the yarn.
The choice between the method of this Example and that of the following Example depends on what the needs of the end use application are, as discussed below.
The manufacturing method of this Example utilizes a Murata MJS or MVS spinning machine similar to that utilized in Example 1. l Like the method of Example 1, it inserts a standard or high tenacity continuous filament ucoren by the use of a core attachment. It differs in that it produces a two-layer sheath which is created by the use of a T-trumpet 71 . The functional distinguishing feature of this method is its ability to control the placement of sliver. The T-trumpet 71 , unlike the standard trumpet 7 normally used to feed carded staple into the spinning frame, allows the feeding of two different types of carded sliver 51 and 53 into the spinning frame in such a way that one fiber type is placed on the inside of the yarn's sheath and another fiber type on the outside of the yarn's sheath. The T-trumpet 71 is shown in more detail in FIG. 6 , where the inner sheath sliver 51 , illustratively PCR-PET, is emerging from the vertical arm 73 of the T-trumpet, and the outer sheath sliver 53 , Illustratively standard or high tenacity nylon, is emerging from the horizontal arm 75 of the T-trumpet. As shown in FIG. 6 , a condenser 10 is included between the back rolls 9 and middle rolls 11 . When spun by the nozzles 21 , the outer edges of the silver 53 become the outer portion of the outer sheath of the finished yarn 81 , and the sliver 51 becomes the inner sheath surrounding the core 17 , as shown in FIG. 7 .
This method will not produce a 100% differentiation of inner and outer sheath fiber types; however, it will be very close. A small amount of the sliver 51 will migrate into the outer sheath, and a small amount of the sliver 53 will migrate into the inner sheath. Any yarn chosen to be manufactured with this method will have the ability to tolerate a less than perfect fiber differentiation. In fact the only time where this differentiation becomes important is when the yarn or fabric is color dyed and the two sheath materials require different dyes. For example, with a cotton exterior sheath and the standard polyester interior sheath, the cotton will be dyed with a cotton dye; however, the polyester will remain white and unaffected by the cotton dye. Therefore, a polyester dye must be used either simultaneously or separately along with the cotton dye in order to achieve color uniformity.
This manufacturing technique is suitable for all end use products except those which are being indigo dyed. Exterior sheath staple fibers which are compatible with this spinning technique include, for example, high tenacity fibers (such as high-tenacity nylon, glass, carbon, and aramid), low friction fibers, antimicrobial fibers, moisture management fibers (such high moisture permeability fibers and moisture repelling fibers), and natural fibers (such as cotton, wool, silk, rayon, and linen), or any blend of these fibers. Many of these fibers are characterized by having inherently long lengths or by being unpredictable in length due to the fact that they are natural fibers. Because of these characteristics, prior to spinning, fibers substantially shorter than 1.5 inches (3.8 cm) must be removed, and fibers substantially longer than 1.5 inches (3.8 cm) must be cut to 1.5″ (3.8 cm) length. The central reason for this is that the optimal spinning frame for these yarns is a Murata MJS or MVS (Murata Machinery, Ltd.), and these machines require a 1.5″ (3.8 cm) staple length. However, it has been found that shorter fibers tend to migrate to the outside of the yarn and longer fibers tend to migrate Inward. Therefore, the amount of intermingling of fibers in the sheath may be minimized by including at least some slightly shorter staples in the sliver for the outside sheath (perhaps somewhat longer than 1.2 inches) to fill the outside sheath, while eliminating such shorter staples in the sliver for the inner sheath. It may also be possible, although it is not presently preferred, to use modify the sliver for the inner sheath by adding slightly longer sliver (perhaps somewhat shorter than 1.8 inches) or by intermixing a little of the shorter staples of the fibers of the outer sheath.
The key reason why the use of Murata's air jet technology is preferred over ringspun technology, is that the Murata air jet yarn manufacturing process involves among other elements, a portion of the fiber which is channeled to the side; while the remainder of the fibers are twisted together in one direction; the channeled fiber acts independently by rapidly wrapping itself around the fiber in twist formation. The critical thing to recognize here, is that the wrapping fibers are not only the fastener of the “false twist”, but in this case, because of the fiber control provided by the T-trumpet, these fibers are an entirely different fiber type than the fibers which are being falsely twisted and being wrapped.
EXAMPLE 4
Second Alternative Yarn Construction
This technique is characterized by its ability to be used in indigo dye applications such as denim. The unique circumstance with denim is that the yarn used in denim is dyed with indigo dye while still in yarn form. The yarn is dipped in indigo dye and then aired. The reason for this is that by performing this dip and air procedure you allow only the surface cotton fibers of the yarn to absorb the indigo dye. This becomes important when the woven fabric is stonewashed. During subsequent stone washing some of the indigo dye contained in the surface cotton fibers is beaten out of the fabric, allowing the undyed white interior of the yarn/fabric to come into sight. This in turn gives the fabric a faded appearance.
In order to adapt my yarn design to be applicable to indigo dyed yarn and fabric manufacturing, a technique of yarn spinning is required which enables the yarn to have an outer sheath which consists 100% purely of one fiber type, which in the case of denim is essential to performing the stonewashing of the indigo dyed cotton without having a visible color variation.
The manufacturing method of this Example comprises using the Intermediate corespun yarn 1 of Example 1, containing a high tenacity, standard tenacity, or stretch continuous filament yarn core and a PCR-PET staple fiber sheath, as the core of a second corespun yarn. The intermediate yarn 1 is fed into the machine of FIG. 1 , and the sliver is whatever staple fiber is desired as the pure 100% surface of the yarn 81 and of a fabric woven or knit from it.
EXAMPLE 5
High Strength Multifilament Yarn Construction
A continuous and multi-filament yarn having a total denier of 12 to 800 and consisting of 10 to 90% by weight of continuous high tenacity and high modulus monofilaments such as aramid, glass, carbon, or any other fiber filament which has a tenacity higher than 15 and a modulus higher than 500 is provided for use as a core in the foregoing Examples, as a ripstop grid, and for other purposes. The high tenacity, high modulus fiber will be intermingled with monofilaments having a lower tenacity, lower modulus, such as high tenacity nylon, regular nylon, high tenacity polyester, regular polyester, or any other continuous filament fiber having a tenacity rating between 5 and 15. l The ratio of the higher than 15 tenacity fiber to the lower than 15 high tenacity fiber is determined by the strength requirements of its end use application and the actual tenacity ratings of the fibers which are being intermingled.
The yarn forms a particularly good core for the PCR-PET sheath yarns of other embodiments of the invention, as well as being an outstanding ripstop yarn used in forming a ripstop grid in a high-strength fabric.
All the patents and articles mentioned herein are described as an integral part of this disclosure with regard to the technical disclosure and are incorporated herein by reference.
Numerous variations in the methods and products of this Invention, within the scope of the appended claims, will occur to those skilled in the art in light of the foregoing disclosure. Merely by way of example, the core materials, sheath materials, and (in the construction of Example 2) cover materials may all be varied to meet particular requirements. The core of the yarn of Example 2 may be omitted, although it is believed that its omission will weaken the yarn. The intermediate yarn 1 may be formed by other spinning methods, as may the sheaths of Examples 3 and 4, although the methods disclosed are believed to provide superior yarns. Staple fibers having a larger range of lengths and diameters may be utilized if other spinning frames are used. These variations are merely illustrative.
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Enhanced performance yarns which are functional alternatives to 100% petroleum oil based virgin continuous filament yarns, and yarns of natural fibers and methods of making them. The yarns may comprise an inner portion of spun staple fibers of recycled plastic and an outer portion comprising a different material and incorporate highly significant amounts of recycled plastics, particularly post consumer recycled, thermoplastic material such as polyethylene terephthalate which contains medium to high levels of contamination. One embodiment of yarn comprises a core, an inner portion of spun staple fibers surrounding the core, and an outer portion comprising an inner helix and an outer helix.
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