This invention provides a process a process for recovering terephthalic acid from pulverized products of spent polyethylene terephthalate. This process comprises (1) a decomposition reaction step where the pulverized products of spent polyethylene terephthalate are continuously subjected to decomposition reaction in ethylene glycol in the presence of alkali, which is equimolar or excessmolar relative to the polyethylene terephthalate, so that salt of terephthalic acid and ethylene glycol can be continuously obtained; (2) a solid-liquid separation, dissolution, impurities-removing step where the ethylene glycol is separated from decomposition reaction slurry of salt of terephthalic acid and ethylene glycol, and the solid salt of terephthalic acid is dissolved into water, while insoluble impurities are removed; (3) a neutralization, crystallization step, where solution of said salt of terephthalic acid is neutralized with acid so that terephthalic acid can be crystallized; (4) a solid-liquid separation, washing step where slurry of terephthalic acid crystals is subjected to solid-liquid separation so that the terephthalic acid crystals can be obtained and washed; and (5) a drying, pulverization step where the washed terephthalic acid crystals are dried and pulverized.

1. Field of the Invention
This invention relates to a process for technically recovering terephthalic acid as the material of polyethylene terephthalate (PET), from spent PET, which is used as bottles containing beverages and the like and also to a system for use in such process.
2. Background of the Invention
Several methods have been proposed in each of which, PET is decomposed for recovering monomer components therefrom, and thus recovered monomer components can be used as the material of PET. Among these conventional methods, typical ones are listed below.
(1) Methanolysis method where depolymerization is carried out for PET with methanol in vapor phase or liquid phase for producing dimethyl terephthalate;
(2) Glycolysis method where depolymerization is carried out for PET with ethylene glycol for utilizing an intermediate product, i.e., bis hydroxyethyl terephthalate as the, material of polymer; or Ester interchange method where dimethyl terephthalate is obtained from the product of the Glycolysis method, i.e., bis hydroxyethyl terephthalate with methanol; and
(3) Hydrolysis method where hydrolysis is carried out for PET with alkali solution so that the resulting metallic salt terephthalate is neutralized with acid for the crystallization of terephthalic acid.
However, the above methods have drawbacks respectively.
In the method (1) (Methanolysis method), its reaction temperature is so low of about 177xc2x0 C., which requires a lot of reaction time.
The method (2) (Glycolysis method), like the method (1) (Methanolysis method), also requires a lot of reaction time. Additionally, it is difficult to depolymerize perfectly to recover the monomer components. Further, the intermediate product, i.e., bis hydroxyethyl terephthalate is partly dissolved into the ethylene glycol. Then, it is difficult to separate the dissolved bis hydroxyethyl terephthalate from the ethylene glycol, which results in poor yield.
In the method (2) (Ester interchange method), it is difficult to separate the ethylene glycol from the methanol. Further, since the dimethyl terephthalate is partly dissolved into the methanol, it is also difficult to separate the dissolved dimethyl terephthalate from the methanol.
In the method (3) (Hydrolysis method), it is more difficult to produce the terephthalic acid than the case of bis hydroxyethyl terephthalate and the case of dimethyl terephthalate. Further, the recovered terephthalic acid might be contaminated with various additives contained in the spent PET, which results in a problem.
To cope with the above problems, Japanese Published Unexamined Patent Application No. 286744/97 proposes a method, in which PET is decomposed with alkali in ethylene glycol.
However, the method disclosed in this patent publication has a problem because the terephthalic acid is not sufficiently recovered. Therefore, it is necessary to attain a method for recovering a polymer having high purity. Additionally, since these conventional methods are performed in pilot scales, there is an increased demand for establishment of practical and technical process of this kind.
It is therefore, the object of the present invention is to provide a technical and practical process of this kind with high recovery of terephthalic acid. The other objects of the present invention will be clear from the following explanation.
In accordance with the first aspect of the present invention, there is provided a process for recovering terephthalic acid from pulverized products of spent polyethylene terephthalate, the process comprising the following steps;
(1) a decomposition reaction step where the pulverized products of spent polyethylene terephthalate arm continuously subjected to decomposition reaction in ethylene glycol in the presence of alkali, which is equimolar or excessmolar relative to the polyethylene terephthalate, so that salt of terephthalic acid and ethylene glycol can be obtained;
(2) a solid-liquid separation, dissolution, impurities-removing step where the ethylene glycol is separated from decomposition reaction slurry of the salt of terephthalic acid and ethylene glycol, and the solid salt of terephthalic acid is dissolved into water and insoluble impurities are removed;
(3) a neutralization, crystallization step, where the resulting solution of salt of terephthalic acid is neutralized with acid so that terephthalic acid can be crystallized;
(4) a solid-liquid separation, washing step where the resulting slurr of terephthalic acid crystals is subjected to solid-liquid separation so that the terephthalic acid crystals can be obtained and washed; and
(5) a drying, pulverization step where the washed terephthalic acid crystals are dried and pulverized.
According to the first aspect of the present invention, the terephthalic acid having high purity can be technically recovered with high efficiency from the pulverized products of spent polyethylene terephthalate.
The alkali comprising mainly sodium carbonate can be used as the above alkali and sulfuric acid can be used as the above acid. Due to the alkali comprising mainly the sodium carbonate, carbon dioxide is generated by the decomposition reaction, thus inlet gas is not required. Further when the sulfuric acid is used as the acid, the sodium sulfate (mirabilite) can be crystallized by the neutralization and recovered.
Water contained in liquid obtained by separation in the step (4) (the solid-liquid separation, washing step) is vaporized so that the sodium sulfate can be crystallized and separated. The resulting steam is condensed for re-using as the water for dissolving the salt of terephthalic acid, whereby the amount of required water can be decreased.
In the step (2) (solid-liquid separation, dissolution, impurities-removing step), by utilizing a crossfeed belt type vacuum filtering dissolver, the separation of the ethylene glycol, the dissolving of the solid salt of terephthalic acid, and the removing of the insoluble impurities can be continuously carried out.
The process in accordance with the first aspect of the present invention might further comprise the following steps:
(6) a return step where the ethylene glycol, which is obtained by the solid-liquid separation in the above step (2) (solid-liquid separation, dissolution, impurities-removing step) is returned to the step (1) (decomposition reaction step); and
(7) a vaporization, crystallization, separation, return step where water contained in separation liquid obtained from the step (4) (the solid-liquid separation, washing step) is vaporized so that the salt can be crystallized and separated, then the reminder, i.e., the ethylene glycol is returned to the step (1) (decomposition reaction step).
By returning the ethylene glycol, the amount of required ethylene glycol can be decreased.
The process in accordance with the first aspect of the present invention might further comprise, between the step (2) (solid-liquid separation, dissolution, impurities-removing step) and step (3) (neutralization, crystallization step), the following step;
(8) soluble impurities-removing step where soluble impurities, which are contained in solution in the above step (2), can be continuously removed with an adsorbent packed adsorber.
As water used for the dissolution in the above step (2), wash water of the adsorber in the step (8) and/or condensate obtained by cooling steam in the step (7) can be re-used for saving water.
Between the above step (1) (decomposition reaction step) and step (2) (solid-liquid separation, dissolution, impurities-removing step), the decomposition reaction slurry can be passed through orifice means. Due to this orifice means, the ethylene glycol can be partly prevented from being passed to the step (2). This means that the slurry having small amount of ethylene glycol is passed to the step (2). Accordingly, load applied to the step (2) can be lowered.
The above orifice means might comprise: a tapered cylinder and a screw conveyor placed in the cylinder. The orifice means of this kind can be easily formed by providing tapered cylinder and the screw conveyor placed in an outlet portion of a screw press.
In the above step (1) (decomposition reaction step), a horizontal type decomposition reactor can be used. This reactor comprises: a cylinder, which has a body portion and a tapered portion connected to the fore end portion of the body portion; and a screw conveyor, which is placed in the cylinder and which has a tapered portion corresponding to the above tapered portion of the cylinder. Then, the pulverized products of spent polyethylene terephthalate, ethylene glycol, and alkali are charged into the above horizontal type decomposition reactor. In this reactor, the ingredients are subjected to the decomposition reaction, mainly in the body portion, so that the salt of terephthalic acid and the ethylene glycol can be obtained. Finally, the resulting decomposition reaction slurry can be extruded from the tapered portion of the cylinder.
For the neutralization of the step (3) (neutralization, crystallization step), the above solution of salt of terephthalic acid can be fed into a neutralization chamber, where the solution is subjected to acid jetting. Then, acid jetting point is moved peripherally with the passage of time. By such movement of jetting point, the neutralization can be promoted in the neutralization chamber, which enables complete neutralization while any unreacted acid is not remained.
For the neutralization of the step (3) (neutralization, crystallization step), ultrasonic vibration can be applied in the neutralization chamber. Also due to the ultrasonic vibration, the neutralization can be promoted, which enables complete neutralization while any unreacted acid is not remained.
For the drying of the step (5) (drying, pulverization step), indirect heating is performed by heating medium passing through a jacket and/or an agitating blade means under reduced pressure of inside of a container for the drying. By drying the terephthalic acid crystals in this way, the degeneration of terephthalic add can be prevented, and the terephthalic acid crystals can be dried in short time.
For the washing of the step (4) (solid-liquid separation, washing step), the slurry of terephthalic acid crystals is supplied to a running filter cloth. Then, this filter cloth is divided into a plurality of filtering and washing zones along the running direction of the filter cloth. In one filtering and washing zone, wash water is sprayed and the slurry is filtered by vacuum suction so that filtrate is obtained under this filtering and washing zone. This filtrate is used as a wash water in another filtering and washing zone located at the upstream side of the above filtering and washing zone, that is to say, counter-flow type washing is carried out. In this embodiment, the filtering and washing can be performed efficiently.
In accordance with the second aspect of the present invention, there is provided a process for recovering terephthalic acid from pulverized products of spent polyethylene terephthalate, the process comprising the following steps;
(1) a decomposition reaction step where the pulverized products of spent polyethylene terephthalate are subjected to decomposition reaction in ethylene glycol in the presence of alkali, which is equimolar or excessmolar relative to the polyethylene terephthalate, so that salt of terephthalic acid and ethylene glycol can be obtained;
(2) a solid-liquid separation step where the ethylene glycol is separated from decomposition reaction slurry of the salt of terephthalic acid and the ethylene glycol;
(3) a dissolution step where the salt of terephthalic acid, which is obtained by separating ethylene glycol from the slurry, is dissolved into water;
(4) a neutralization, crystallization step where the resulting solution of salt of terephthalic acid is neutralized with acid so that terephthalic acid can be crystallized;
(5) a solid-liquid separation, washing step where the slurry of terephthalic acid crystals is subjected to solid-liquid separation so that the terephthalic acid crystals can be obtained and washed; and
(6) a drying, pulverization step where the washed terephthalic acid crystals are dried and pulverized.
As shown in the second aspect of the present invention, even if the step (2) (solid-liquid separation step) and the step (3) (dissolution step) are performed separately, the directing terephthalic acid can be obtained smoothly.
In the above step (1) (decomposition reaction step), a vertical type stirring vessel can be used for the decomposition reaction. When operation is passed from the step (1) to the step (2), the decomposition reaction slurry can be passed through a vertical type orifice means. This orifice means comprises a tapered cylinder and a screw conveyor placed in this cylinder. Due to this orifice means, the ethylene glycol can be partly prevented from being passed to the step (2). On the other hand, the ethylene glycol can be returned to the stirring vessel from the larger diameter side of the above cylinder. Thus, the slurry containing small amount of ethylene glycol can be passed to the step (2). Accordingly, load applied to the step (2) can be lowered.
In accordance with the third aspect of the present invention, there is provided a process comprising a decomposition reaction step where pulverized products of spent polyethylene terephthalate are subjected to decomposition reaction in solvent in the presence of alkali, which is equimolar or excessmolar relative to the polyethylene terephthalate, so that salt of terephthalic acid and ethylene glycol can be obtained, for recovering terephthalic acid from the resulting salt of terephthalic acid, and the above decomposition reaction step being constructed from equal to or more than two stages, i.e., multiple stages.
The pulverized products of spent PET are formed by crushing PET bottles or the like. Then, each PET article of this kind has many parts made of different materials, thus time required for decomposition reaction is different for each part. Accordingly, in order to decompose completely the pulverized products of spent PET, it takes time long enough to decompose a part where the decomposition reaction is slowest among all the parts. Precisely, even after the decomposition reaction is completed at a certain part, this process can not move to next step as long as decomposition reaction is occurred at any part. This causes low efficiency.
In this connection, in the third aspect of the present invention, since the decomposition reaction step is constructed from equal to or more than two stages, i.e., multiple stages, the decomposition reactions in the parts of the pulverized products are performed in corresponding stages, respectively, so that the reactions in these all parts ran be finished simultaneously, resulting in improved efficiency of the process.
As one embodiment in accordance with this aspect of the present invention, the above decomposition reaction step might comprise two stages; a previous heating stage and a decomposition reaction heating stage. In the previous heating stage, the above pulverized products are previously heated for 5 minutes or more at the temperature range from 100xc2x0 C. to the temperature at which the decomposition reaction of the above pulverized products is not substantially started. On the other hand, in the decomposition reaction heating stage, the above pulverized products are subjected to the decomposition reaction at the temperature range from the temperature at which the decomposition reaction of the above pulverized products is substantially started and the boiling point of the solvent.
As the solvent, ethylene glycol can be used and the above pious heating can be performed at the temperature of 100 to 140xc2x0 C., while the above decomposition reaction can be performed at the temperature of 130 to 180xc2x0 C.
As stated above, as for the previous beating stage, where the above pulverized products are previously heated for 5 minutes or more at the temperature range from 100xc2x0 C. to the temperature at which the decomposition reaction of the above pulverized products is not substantially started, and as for the decomposition reaction heating stage where the above pulverized products are subjected to the decomposition reaction at the temperature range from the temperature at which the decomposition reaction of the above pulverized products is substantially started to the boiling point of the solvent, particularly, if the ethylene glycol is used as the solvent, the above previous heating temperature is 100 to 140xc2x0 C., while the above decomposition reaction temperature is 130 to 180xc2x0 C. By performing the previous heating before the decomposition reaction, the amorphous pars of the pulverized products of spent PET are crystallized and subjected easily to the decomposition reaction. As a result, the decomposition reactions in these all parts can be finished simultaneously, resulting in improved efficiency of the process in the decomposition reaction stage.
Further, before the previous heating stage, impurities, each of which has smaller specific gravity than that of the solvent, are preferably removed.
Generally, tee pulverized products of spent PET contain impurities such as polypropylene (PP) and polyethylene (PE). When the impurities are heated, they will surely melt. Hence, it is difficult, after heating, to remove such impurities. Then, if the impurities are not removed but remained, they will solidify when they are cooled. This might cause trouble in the other steps continuing after the decomposition reaction step. In order to avoid such trouble, it is preferable that the impurities such as PP and PE are removed before heating. Actually, the impurities float on the solvent such as ethylene glycol and water, because of smaller specific gravity than that of the solvent. Therefore, it is surely possible that the floating impurities are removed from the solvent before heating. Particularly, when the ethylene glycol is used as the solvent, such impurities can be removed easily, due to the large difference of specific gravity between the impurities and the ethylene glycol.
As a decomposition reactor used for a final stage of the above decomposition reaction step, a horizontal type decomposition reactor can be used. This reactor comprises: a cylinder, which has a body portion and a tapered portion connected to the fore end portion of the body portion; and a screw conveyor, which is placed in the cylinder and which has a tapered portion corresponding to the above tapered portion of the cylinder. Then, the pulverized products of spent polyethylene terephthalate, solvent, and alkali are charged into this horizontal type decomposition reactor. Continuously, the above pulverized products are subjected, mainly in the above body portion, to the decomposition reaction so that the salt of terephthalic acid and the ethylene glycol can be obtained. Finally, the resulting decomposition reaction slurry can be extruded from the tapered portion of the cylinder.
When the decomposition reaction slurry goes to the next step, since the slurry is extruded from the tapered portion as stated above, large amount of solvent is not required to be included in the slurry. Accordingly, the load applied to the next step can be lowered. Additionally, such extrusion is carried out continuously after the decomposition reaction in the horizontal type decomposition reactor. Therefore, any additional equipment for the extrusion is not required.
The sodium carbonate is preferably used as the alkali. Additionally, it is preferable that the mass ratio of the pulverized products of spent polyethylene terephthalate and the ethylene glycol is determined to be 1:0.8 to 1.2 in the previous heating and to be 1:2.0 to 2.5 in the decomposition heating.
When the sodium carbonate is used as the alkali, the pulverized products of spent PET are subjected to the decomposition reaction so that the sodium terephthalate and the ethylene glycol can be obtained. In this situation, the sodium terephthalate absorbs the ethylene glycol. Then, as stated above, in a certain part where the decomposition reaction is fast, even after the decomposition reaction of this part is completed, the reaction is continued due to the part where the decomposition reaction is slowest That is to say, after the decomposition reaction of this part is completed, sodium terephthalate continues to absorb the ethylene glycol as long as the decomposition reaction is occurred in other parts. This requires large amount of ethylene glycol.
In this connection, in the fourth aspect of the present invention, by provision of the previous heating, the decomposition reactions of the all parts of the pulverized products of spent PET can be finished simultaneously. Accordingly, the amount of ethylene glycol absorbed into the sodium terephthalate can be deceased. Then, if the mass ratio of the pulverized products of spent PET and the ethylene glycol is determined to be 1:0.8 to 1.2 in the previous heating, and it is determined to be 1:2.0 to 2.5 in the decomposition heating, the reactions can be carried out efficiently in both cases. As a result, the consumption of the ethylene glycol can be decreased. Here, the amount of ethylene glycol in the decomposition reaction heating refers to not the amount of ethylene glycol added in the decomposition reaction stage, but the total of the amount of ethylene glycol added in the previous heating stage and the amount of ethylene glycol added in the decomposition reaction stage.
In accordance with the fourth aspect of the present invention, there is provided a process comprising decomposition reaction heating carried out for the pulverized products of spent polyethylene terephthalate in solvent in is the presence of alkali, which is equimolar or excessmolar relative to the polyethylene terephthalate, so that salt of terephthalic acid and the solvent can be obtained, for recovering terephthalic acid from the resultant salt of terephthalic acid, and before the decomposition reaction, the above pulverized products are subjected to thermal degradation.
As stated above, each PET article such as PET bottle for beverage has many parts made of different materials, b, time required for decomposition reaction is different for each part. Accordingly, even after decomposition reaction is completed at a certain part, operation can not be passed to the next step as long as decomposition reaction is occurred at any part. In this connection, in accordance with the fourth aspect of the present invention, before the above decomposition reaction, the pulverized products of spent PET are subjected to thermal degradation so that the decomposition reactions in the all parts are finished simultaneously. Particularly, if this thermal degradation is performed at the temperature of 290 to 330xc2x0 C. for more than 5 minutes, the amorphous parts of the pulverized products of spent PET are crystallized and subjected easily to the decomposition reaction As a result, the decomposition reaction can be finished quickly, resulting in high efficiency.
The thermal degradation can be carried out continuously and easily by utilizing a screw extruder.
Further, heat generated by the pulverized products subjected to the thermal degradation can be recycled for the decomposition reaction heating. This means that heat can be used efficiently, thereby efficient process can be attained. After the thermal degradation of the pulverized products, they are fed to the decomposition reaction step, where they are heated. Then, the amount of the fed pulverized products can be adjusted. By doing so, temperature control in this step is enabled.
In accordance with the fifth aspect of the present invention, there is provided a process for technically recovering terephthalic acid from pulverized products of spent polyethylene terephthalate. This process comprises: a thermal cracking course where the pulverized products of spent polyethylene terephthalate are subjected to thermal cracking in the presence of solvent and alkali so that salt of terephthalic acid and ethylene glycol can be obtained; and a removing course where the solvent is removed from thermal cracking slurry, by vaporizing the solvent under the atmospheric pressure or reduced pressure from the thermal cracking slurry, for recovering terephthalic acid from the resulting salt of terephthalic acid.
In order to remove the solvent from the thermal cracking slurry, i.e., to separate the thermal cracking slurry into the salt of terephthalic acid and the solvent, it is common that a filter or centrifugal separator is used. However, if such equipment is used, since the particles of the salt of terephthalic acid are very fine, the amount of the removed solvent can not be stable. Additionally, the removing operation takes long time. On the other hand, in this aspect of the present invention, the solvent is vaporized under the atmospheric pressure or reduced pressure. Accordingly, the amount of the removed solvent can be controlled freely and the removing operation can be carried out quickly.
Further, in this aspect of the present invention, there is provided a process for technically recovering terephthalic acid from pulverized products of spent polyethylene terephthalate. This process comprises: a thermal cracking course where the pulverized products of spent polyethylene terephthalate arc subjected to thermal cracking in the presence of solvent and alkali so that the salt of terephthalic acid and ethylene glycol can be obtained; and a removing course where the solvent is removed from the thermal cracking slurry, by vaporizing the solvent under the atmospheric pressure or reduced pressure until the amount of the solvent contained in the solid salt of terephthalic acid is decreased to 20 to 30% by mass thereof, for recovering the terephthalic acid by dissolving the solid salt of terephthalic acid into water.
In this embodiment, the solvent and the ethylene glycol are removed from the solid salt of terephthalic add until the amount of the solvent contained in the solid salt of terephthalic acid is decreased to 20 to 30% by mass thereof. Therefore, the amount of water required to dissolve the solid salt of terephthalic can be decreased due to the certain amount of solvent contained in the solid salt of terephthalic acid.
To carry out the process according to this embodiment, there is provided a system recovering terephthalic acid from pulverized products of spent polyethylene terephthalate. This system comprises: a horizontal type decomposition reaction chamber; stirring means for stirring solvent, alkali, and the pulverized products of spent polyethylene terephthalate, which are charged into the decomposition reaction chamber; heating means for heating the same; a vacuum chamber, which is communicated with the upper portion of the above decomposition reaction chamber; and evacuating means, which is connected to the vacuum chamber. Then, in this system, the solvent contained in the above decomposition reaction chamber is removed through the above vacuum chamber, and the resulting solid salt of terephthalic acid will be used for recovering the terephthalic acid.
This system has the vacuum chamber, which is communicated with the upper portion of the decomposition reaction chamber, and evacuating means, which is connected to this vacuum chamber. Then, by forming a vacuum in the decomposition reaction chamber, the solvent can be vaporized. That is to say, the decomposition reaction chamber can be used not only for the decomposition reaction but also for the removing of solvent. Therefore, any additional equipment is not required for removing the solvent. Additionally, in this system, beat can be used efficiently.
In this aspect of the present invention, carbonate can be used as the alkali. When the carbonate is used as the alkali, carbon dioxide is generated the moment the decomposition reaction is started. Accordingly, the decomposition reaction chamber can be configured so as to be sealed internally by thus generated carbon dioxide. In this case, inert gas (e.g, nitrogen) is not required for this sealing.
Further, according to this embodiment, there is provided a system recovering terephthalic acid from pulverized products of spent polyethylene terephthalate. This system comprises: a decomposition reactor where the pulverized products of spent polyethylene terephthalate are subjected to thermal cracking in the presence of solvent and alkali so that salt of terephthalic acid and ethylene glycol can be obtained; an evaporator having a heating surface kept at the temperature equal to or higher than the boiling point of the above solvent; and falling means, by which the above thermal cracking slurry is fallen downward to the heating surface. Then, in this system, the solvent vaporized in the above evaporator is recovered axed returned to the above decomposition reactor.
In this system, by the falling means, the thermal cracking slurry of the salt of terephthalic acid and ethylene glycol can be brought into contact with the heating surface kept at the temperature equal to or higher than the boiling point of the above solvent, the solvent can be vaporized quickly. Further, the temperature of the heating surface can be adjusted so that the amount of removed solvent can be controlled freely.
In accordance with the sixth aspect of the present invention, there is provided a process for technically recovering terephthalic acid from pulverized products of spent polyethylene terephthalate. This process comprises: subjecting the pulverized products of spent polyethylene terephthalate to thermal cracking in the presence of alkali so that salt of terephthalic acid and ethylene glycol can be obtained; removing the ethylene glycol from thermal cracking slurry so that solid salt of terephthalic acid can be obtained; dissolving the solid salt of terephthalic acid into water so that solution of salt of terephthalic acid can be obtained; neutralizing this solution of salt of terephthalic acid by adding acid so that terephthalic acid can be crystallized and recovering the terephthalic acid. Then, in this process, the acid is added in multiple stages and the amount of added acid is determined so that the pH value of the solution in the final stage is adjusted to 2 to 4. Further, in this process, the terephthalic acid crystals obtained from the fin stage are returned to a previous stage and dissolved.
For crystallizing the terephthalic acid, it is usually considered that solution of salt of terephthalic acid is neutralized by adding acid until the pH value of the solution is adjusted to about 2. However, in this case, the particle size of each resulting terephthalic acid crystals is too small. To cope with this problem, there is provided a method where the acid is added to the solution of salt of terephthalic acid under high pressure at the temperature of 100 to 200xc2x0 C. so that the terephthalic acid crystals each having large particle size can be obtained. However, this method makes the facility to be complicated, resulting in high cost. Further, since thus obtained terephthalic acid might form capillary crystals, the crystals tend to break. As a result, the terephthalic acid crystals each having the large particle size can not be obtained by the conventional methods.
On the other hand, according to the process of this aspect, the terephthalic acid crystals each having large particle size can be obtained at low cost.
It is preferable that the amount of added acid is determined so as not to crystallize the terephthalic acid in the proceeding stage.
It is also preferable that the acid is added in multiple stages while the amount of added acid is determined so that the pH value of the solution obtained from the final stage is adjusted to 2 to 4 and this solution is fed into a classifier so that classified terephthalic acid fine crystals are returned to a previous stage together with mother liquor. This embodiment ensures the terephthalic acid laving the large particle size.
It is possible that the solution containing the terephthalic acid crystals is subjected to solid-liquid separation so that the resulting terephthalic acid crystals are returned to the previous stage for dissolution again.

Process for recovering terephthalic acid from pulverized product of spent polyethylene terephthalate and system for use in such process


An apparatus and method supports thermal processing of a microelectronic device such as a semiconductor chip in a substrate by heating the substrate with secondary radiation from an energy transfer device 40, which has a first set of energy transfer regions comprised of an emissive and thermally conductive material, and a second set of thermally insulating regions comprised of a reduced emissivity and reduced thermal conductivity material or free space. A multi-zone radiant energy source 30 provides radiative energy to energy transfer device 40, with a process controller 36, preferably a multi-zone controller, altering the amount of energy provided by each heat zone associated with each emissive region of energy transfer device 40. Sensors detect the thermal energy level of each energy transfer region to allow controller 36 to adjust the secondary radiation emitted by each region in real time, resulting in a predetermined and controlled distribution of thermal energy on substrate 20. Energy transfer device 40 can have plural emissive and thermally conductive concentric rings separated from each other by reduced emissivity and reduced thermal conductivity regions such as free space gaps 42. Alternatively, a solid plate 54 having an emissive coating or emissive surface 52 can have reduced emissivity and reduced conductivity isolation regions such as trenches 56 for defining the multi-zone high-emissivity and high thermal conductivity energy transfer regions.

Semiconductor devices can be formed on silicon wafer substrates by the use of certain fabrication processes some of which involve the application of heat (e.g., in the range of 200.degree. C. to 1100.degree. C.) to the substrate in a controlled environment. Several processing methods for fabricating a device onto a substrate have evolved which include the application of thermal energy to the substrate to drive thermally activated fabrication processes. For instance, chemical-vapor deposition (CVD) processes can deposit various materials on a substrate, including metallic, semiconductor and insulating material layers. Thermal deposition processes and thermal anneal processes can support silicide formation. These chemical and thermal processes can form a microelectronic device such as an insulated gate field-effect transistor (IGFET) on a substrate by manipulating, forming or modifying materials such as silicon dioxide, silicon nitride, tungsten, polysilicon and other known materials. Well-known single-wafer rapid thermal processing (RTP) applications include rapid thermal annealing (RTA), rapid thermal oxidation (RTO), rapid thermal chemical-vapor deposition (RTCVD) processes, and rapid thermal nitridation (RTN).
During the formation of a device such as an IGFET on a substrate by thermal processing techniques such as RTP methods, consistent production of a high-quality semiconductor integrated circuit (IC) with high production yield is enabled when the thermal energy is applied in a uniform and repeatable manner. CVC, Inc. ("CVC") has introduced several significant improvements over conventional thermal processing systems and methods for semiconductor IC fabrication. For instance, CVC has developed a multi-zone radiant-energy illuminator for producing heat in silicon substrates during device fabrication as is disclosed in U.S. patent application Ser. No. 08/678,321 filed on Jul. 11, 1996, and entitled "Multi-Zone Illuminator for Rapid Thermal Processing," which is incorporated herein by reference as if fully set forth. This multi-zone illuminator provides improved wafer-to-wafer process and temperature repeatability as well as within-wafer temperature uniformity by monitoring and controlling optical energy produced by plural lamps arranged in multiple heating zones. The multi-zone illuminator also includes a multi-zone temperature measurement system having plural pyrometry sensors for real-time wafer temperature measurement.
Although the multi-zone illuminator provides improved device fabrication uniformity and repeatability, a number of process control difficulties remain with respect to fabrication by rapid thermal processing (RTP). For instance, in one implementation of rapid thermal processing ("RTP") or rapid thermal chemical-vapor deposition ("RTCVD"), a substrate is generally supported by a susceptor during the application of heat. The susceptor can absorb the radiant optical energy and redistribute thermal energy across the substrate thus nullifying or minimizing effectiveness of the control inputs to a multi-zone illuminator. Another limitation relates to the varying emissivity of the substrate during processing due to the dependence of substrate emissivity on temperature and thin films. Although CVC's multi-zone temperature sensing and control technology in conjunction with multi-zone illuminators can compensate for variations in wafer emissivity (due to any source such as temperature and/or material layers), this compensation can introduce some errors and requires complicated control algorithms which can depend upon extensive testing and calibration runs for each type of substrate being processed. Another difficulty relates to the size and makeup of the susceptor used to support a substrate. The heating susceptor can introduce residue contaminants (e.g., metallic contaminants) to the substrate when the susceptor is in physical contact with the substrate. Also, to provide adequate mechanical support of the substrate, the susceptor can be made of a relatively large mass of thermally conductive material. The larger the mass of a conventional heating susceptor, the more difficult it is to estimate and control the heat energy absorbed and emitted by the susceptor. Moreover, high-thermal-mass susceptors significantly slow down the wafer heating and cooling times, resulting in reduced wafer processing throughout.

High-performance energy transfer system and method for thermal processing applications


A frame which may be spanned by a panel for mounting by an adhesive or magnetically to the roof of a automotive vehicle to simulate a sunroof and thereby enhance the value and appearance thereof.

Modern automotive vehicles are frequently equipped with sunroofs which may be opened and closed from the interior of the vehicle and which enhance the value and appearance of the vehicle. Frequently, it is desirable to enhance the appearance of a vehicle which originally was not equipped with a sunroof, either to increase the value thereof or to produce a more prestigious sense for the vehicle.
In vans or the like, side windows of various sizes and shapes can normally be provided to provide light and air to the interior lower cost vans, however, may not have side windows. Furthermore, automobiles may have side windows of various configurations and which generally enhance the value of the vehicle or define the style thereof.

Universal motor vehicle appearance enhancer


The invention relates to a stationary blade (12) for a gas turbine (1) with a hollow sectional element (22) which extends radially with respect to the rotor (3) and has a platform (23) at each of its two ends, with a hollow inset (20) which is located in the sectional element (22) a certain distance from the inside (28) of the sectional element (22) and has a base (35) which faces one of the two platforms (23), with a coolant (K) flowing into the hollow space (21) of the inset (20) and flowing out through baffle cooling openings (29) provided on the inset (20) and with a recess (24) that is provided in the platform (23) located immediately opposite the base (35). To specify a stationary blade (12) for which there is no mechanical damage during turbine operation it is proposed that the inset (20) extends into the recess (24) so that in the base area (30) of the inset (20) there are zones with reduced predefined flow rates.

Cooled turbine vane for turbines are generally known. The turbine vanes have a hollow sectional element at the end of which there is a transverse platform. An inset serving as a cooling baffle is accommodated in the hollow sectional element a certain distance from the inside of the outer wall and is provided with a large number of cooling openings. The coolant flows through the openings and hits the inside of the outer wall, thereby cooling it.
Compressor air is usually used as the coolant. Although the compressor air is cleaned by passing it through an air filter before it enters the compressor it still contains fine particles less than 10 μm in diameter. These fine particles, which may consist of dust, material particles or sticky compounds such as sulfur compounds, are often deposited on the inside of the baffle. In addition, agglomerates and corrosion products from these particles may be deposited on the openings of the inset, thereby reducing the cross-section of the opening. This leads to a reduction in the flow rate, and a much reduced cooling effect. This in turn can lead to thermal loads in the outer wall which may cause cracks to form or, in the case of laminated blades, to delamination of the blades.

Turbine and a turbine vane for a turbine


A photographic film is provided with bar codes indicating frame numbers attached to respective frames of the photographic film and a specific bar code indicating a specific part thereof. The specific bar code is located before or after the specific part of the photographic film. Each frame number bar code is read to determine the decimal frame number of each frame of the photographic film. If the bar code attached to the last frame is not read, it is determined that the bar code not read indicates a frame number for the last frame by reading the specific bar code before or after the fault in reading the bar code of the last frame.

The present invention relates to a photographic film and a method of reading a frame number of the photographic film, and more particularly to a photographic film with bar codes indicating frame numbers of the photographic film and a method of reading the bar codes of the photographic film.
A 135-type of roll film is attached with DX binary bar codes indicating the type of film, the speed of the film, or the like. The bar codes are latent images formed in a side margin of the film. Upon printing, the DX bar code is read with a bar code sensor or bar code reader to correct an exposure amount according to the film speed.
The roll film also is attached with main serial frame numbers indicated by decimal numbers and supplementary serial frame numbers indicated by decimal numbers and alphabetical letters arranged at regular intervals which are used to specify the respective frames upon printing. It is known to print a bar code indicating a frame number in addition to each serial frame number so as to read automatically the frame number for identifying a picture frame. The frame number bar code is used to locate automatically a frame in the exposure position for making an extra print of the frame and/or to print a frame number on the print.
Upon loading a roll film in a camera, withdrawing a film leader out of the film patrone reduces the exposures of the film. To make it possible to make as many exposures as assigned, the film is provided with an extra exposable part which is indicated by an identification sign or mark, such as a letter "E" as an extra frame number. For example, a roll film, having 12, 20, 24, or 36 frames, has an extra part or frame attached with an identification mark "E" after a frame number of "12A", "20A", "24A", or "36A", respectively.
In the roll film having an extra frame attached with frame number "E", the bar code reader sometimes erroneously reads the extra frame number "E" if the extra frame number "E" is scratched, has foreign articles, or fogged. As a result, distinguishing the last frame, such as a 12th, 20th, or 24th frame, from the extra frame "E" is difficult. However, because the longest roll film has 36 exposures, the last frame or 35th frame can be distinguished by storing data in the printer indicating that the extra frame "E" is after the 36th frame.
It is, therefore, an object of the present invention to provide a photographic film having frame number bar codes in which the last frame may be distinguished even when the frame number bar code for the last frame is read incorrectly. It is a further object to provide a method of reading frame number bar codes of the film.

Photographic film and method of identifying frame numbers of photographic film


A measuring tool for disc brake device brake pad, which includes a base, a first tube, a second tube, a front rod, a measuring rod, and a spring, wherein the first tube is configured at the front end of the base, the first tube is perforated with a sighthole. The second tube is pivoted in the first tube, and a marking is formed on the exterior of the midsection of the second tube. The front rod is configured at the front end of the second tube, and a pivot hole axially penetrates the front end of the front rod. The measuring rod pivotal penetrates the front rod, the second tube, and the first tube. The rear end of the measuring rod is inserted into the center of the front end of the base. A contact pin extends in a curved sideward direction from the front end of the measuring rod, and the contact pin abut against the front end of a protruding portion. The spring is disposed in the interior of the second tube, and the two ends of the spring respectively abut against the front rod and the base.

(a) Field of the Invention
The present invention relates to a tool used when servicing a motor vehicle disc brake device, and more particularly to a measuring tool for disc brake device brake pad, wherein the measuring tool in question is used to measure the distance between the brake pad and the brake disc.
(b) Description of the Prior Art
A motor vehicle disc brake device is mounted on the wheel axle of a motor vehicle so as to be adjacent to the wheel, and the disc brake device is used to cause the motor vehicle to slow down and brake.
The disc brake device primarily uses a pair of mutually corresponding brake pads respectively mounted on the two sides of a brake disc. The brake disc is connected to the wheel axle of the motor vehicle and rotates in synchronicity with the wheel axle. Each of the brake pads is adjacent to the respective surface of the brake disc, and is provided with a friction block. When each of the brake pads clamps the respective surface of the brake disc, each of the friction blocks contacts the respective side surface of the brake disc. The corresponding friction between each of the friction blocks and the brake disc is used to reduce the rotational speed of the wheel axle, thereby achieving the objective of slowing down and braking the motor vehicle. However, the contact friction between the friction blocks and the brake disc causes wear and tear of the friction blocks, resulting in a gradual decrease in the thickness of the friction blocks. When the thickness of the friction blocks has decreased to being equal to or less than a preset safety value, then neglecting to replace the brake pads will bring about a reduction in the effectiveness of slowing down and braking the vehicle, and thereby endangering driving safety.
The distance between the mutually adjacent surfaces of the brake pads and the brake disc can serve as a basis to determine the thickness of the friction blocks, and accordingly decide whether or not to replace the brake pads.
To measure the distance between the brake pads and the brake disc, the wheel needs to be detached from the wheel axle to expose the disc brake device, then a thickness/gap gauge is used to measure the distance between the brake pads and the brake disc. Hence, such a measuring method requires detaching the wheel, which is time consuming and complicated.

Measuring tool for disc brake device brake pad


A computer is programmed to perform lithography simulation at a number of locations in a transverse direction relative to a length of a feature of an IC design, to obtain simulated intensities at the locations. The computer is further programmed to determine constants of a predetermined formula that models a trend of the simulated intensities as a function of distance (in the transverse direction), by curve-fitting. The computer is also programmed to compute a value (“CD predictor”) based on the just-determined constants, the formula and a known threshold intensity for a given position along the feature's length. The just-described process, of lithography-simulation, followed by curve-fitting, followed by CD predictor computation, is repeatedly performed to obtain a number of CD predictors at a corresponding number of positions along the feature's length. The CD predictors are used to identify a position of a critical dimension, for use in, for example, layout verification.

1. Field of the Invention
The invention relates to verification of layouts used in fabrication of semiconductor wafers that contain integrated circuits (ICs). More specifically, the invention relates to a method and an apparatus for evaluation of criteria related to critical dimension (CD), such as conformity to user specification(s) of CD and/or uniformity of linewidth.
2. Related Art
In the manufacture of integrated circuit (IC) chips, minimum feature sizes have been shrinking according to Moore's law. Currently the minimum feature size is smaller than the wavelength of light used in the optical imaging system. Accordingly it has become increasingly difficult to achieve reasonable fidelity (including resolution and depth of focus) between (a) a layout as designed in a prior art computer in a place and route step 101 (FIG. 1A) and (b) shapes of circuit elements formed in a wafer fabrication step 106 (FIG. 1A). Step 106 normally involves a number of processes such as photolithography followed by metal deposition and chemical mechanical polishing. A result of place and route step 101 is a layout of rectangles shown in FIG. 1B. This illustrative layout has four traces (also called "lines") whose nominal contours (i.e. as designed in the computer) are shown by dashed rectangles 111n-114n. Also shown in FIG. 1B are closed contours 111i-114i which denote shapes of corresponding metal (or other material) as they would be formed if a wafer is fabricated using the layout.
In today's design flows, it is common to perform, after a tapeout step 104, a step 105 (called "mask synthesis") involving optical proximity correction and resolution enhancement, followed by a step 105a of physical verification. In step 105a, a simulation is performed of a lithographic process to be used to build the integrated circuits in a semiconductor wafer, and the simulation generates image intensities to which are applied one or more evaluation criteria such as measurement of critical dimension of contours (such as contours 111i-114i in FIG. 1B). Note that if step 105a finds errors, then the design flow may return to step 105 for additional RET or OPC based corrections but if such changes are insufficient to fix the errors, the flow may return to step 102 (as shown by the dashed arrow in FIG. 1A).
A human user of the prior art computer is typically interested in the minimum width of each trace (also called "critical dimension" and abbreviated as CD) for several reasons, e.g. when CD is too small an IC in the wafer may not perform as designed. In FIG. 1B, the minimum width 113wmin of trace 113 illustrates such a CD. The user may also be interested in uniformity of a trace's width along a longitudinal direction. In FIG. 1B, trace 113i has a maximum width 113wmax larger than nominal width 113w, which can cause a problem.
Determination of dimensions 113wmax and 113wmin can be performed as follows, using a method known to the inventors as follows. A nominal rectangle 113n that represents a to-be-formed trace in the IC is divided up into a number of rectangular portions, such as portions 120, 130 and 140 illustrated in FIG. 1C. Note that all portions of nominal rectangle 113n are not labeled in FIG. 1C, but these portions together appear like a track of a train (hence the method is also called a "gauge" method, and the portions are also called "gauge" portions).
Thereafter, the following process (called "bisection") is repeated for each gauge portion of nominal rectangle 113n. A prior art aerial image simulator is invoked to find (1) a first intensity (FIG. 1D) at nominal center 121 of a current gauge portion, (2) a second intensity a location 122 outside a nominal edge 125 of the current gauge portion, and (3) a third intensity at a midpoint 123 between the location 121 of the first intensity and the location 122 of the second intensity. Note that all the just-described locations 121, 122, 123 and 125 are located at an edge of a gauge portion (e.g. left vertical edge of gauge portion 120 in FIG. 1C) that is transverse to the feature (the feature's nominal polygon 113n is a rectangle that is shown horizontally oriented in FIG. 1C). Then, the third intensity is compared with a known threshold (which when applied to an intensity distribution of the lithographic process, results in a contour).
If the currently-computed third intensity is less than threshold, then its location 123 is used in a next iteration to invoke the aerial image simulator to re-compute the second intensity, followed by re-computing the third intensity again. If the currently-computed third intensity is greater than threshold, then its location 123 is used in the next iteration to invoke the aerial image simulator to re-compute the first intensity, followed by re-computing the third intensity (this time at location 124 in FIG. 1C). In this manner, a number of iterations are performed until a terminating criterion is met. The terminating criterion for the bisection process may be, for example, that the locations of the first and second intensities are sufficiently close to one another (e.g. locations 123 and 124 are sufficiently close) that they fall below a user-specified tolerance on CD location. When such a criterion is met, a linear interpolation between these two locations is used to find the position of contour 113i in the current gauge portion. After such contour positions are determined in every portion, the smallest width among all gauge portions forms the CD.
A prior art aerial image simulator that is used in such a method typically applies a number of mathematical formulations to layout shapes to simulate the lithography process, including not only optical effects (such as resolution and depth of focus) but also resist effects, etch effects etc. A combination of such effects in a semiconductor wafer fabrication process is used to create a layer in the wafer, for example, a metal layer or a polysilicon layer. A prior art aerial simulator may use a kernel-based model of the wafer fabrication process, by convolving an IC layout with convolution kernels to obtain the intensity at a location in a simulated wafer image.
One problem with the bisection process described above is that the aerial image simulator (used to simulate the lithography process) is invoked multiple times in each iteration. Accordingly, determining the location of edges of a single portion in the can easily require several invocations of the aerial image simulator (e.g. 10 invocations), and if there are several portions (e.g. 10 portions), then the total number of invocations per trace is quite large (e.g. 100 invocations total). Inventors find that when an aerial simulator is used so many times, the gauge method be easily scaled up for use in evaluating an IC layout in a reasonable amount of time (a few hours), given the current state of typically-used computing resources (e.g. a workstation containing a 2 GHz CPU and 1 GB memory).
U.S. patent application Ser. No. 11/142,789 entitled "CENTERLINE-BASED PINCH/BRIDGE DETECTION" filed on May 31, 2005 by ZongWu Tang, Juhwan Kim, Daniel Zhang, Haiqing Wei and Gang Huang is incorporated by reference herein in its entirety as background to the current invention. This patent application describes performing lithography simulation only along a centerline of a feature in an IC layout. The layout features whose centerlines are selected (for invoking an aerial image simulator) can either be layout elements, or spaces between layout elements. Certain embodiments simulate the lithographic process only along center lines of features selected for being likely to generate defects in lithography (e.g. a long and narrow layout element that is closely surrounded by other layout elements or a space between layout elements with long facing edges). However, the just-described centerline method can result in some errors under certain circumstances, e.g. (1) if intensity peak has drifted from nominal center of the trace (due to proximity effect of adjacent traces) or (2) if a corner is present adjacent at the end of the trace.
Accordingly, the inventors find there is a need for yet another method to evaluate criteria related to critical dimensions of an IC layout that is faster than the gauge method, and not prone to errors of the centerline method.

Locating critical dimension(s) of a layout feature in an IC design by modeling simulated intensities


Techniques for cloud network automation for IP address and DNS record management are disclosed. In some embodiments, a system, process, and/or computer program product for cloud network automation for IP address and DNS record management includes receiving at a cloud platform appliance (e.g., a virtual or physical IP address and/or DNS management appliance) a cloud request related to a resource (e.g., a virtual or physical resource) in a cloud environment from a global cloud manager; and processing the cloud request at the cloud platform appliance to determine whether to proxy the cloud request to another cloud platform appliance or a grid master or to locally process the cloud request, wherein a storage of infrastructure metadata information for IP address and/or DNS record management is updated based on the cloud request.

The trend towards moving more computing workloads to virtual environments is increasing. The number of virtual machines (VMs) installed at enterprise data centers is also rising as enterprise data centers grow and add more computing workloads.
Virtualization generally allows for a more dynamic computing infrastructure with a higher optimal utilization of physical servers. For example, virtualization allows a single physical machine (e.g., physical server) to host a large number of virtual resources, such as hundreds of virtual resources (e.g., anywhere between less than 20 and more than 200 VMs per server). As a result, there is typically less capital expenditure on computing hardware (e.g., physical servers and/or other computing hardware) when enterprises utilize virtualization for some of their entire computing infrastructure. Virtualization also allows for a pay-as-you-go model for managing compute capacity. In addition, virtualization can also offer flexibility in disaster recovery and dynamic movement of a virtual server from one location to another.

This patent is subject to a terminal disclaimer.

Cloud network automation for IP address and DNS record management


The present disclosure involves a rotational encoder having a plurality of indicia at fixed positions with respect to each other, means for rotating said indicia about an axis and means for sensing the indicia positioned along the path of rotation of said indicia. In the present apparatus, each of a plurality of said indicia has a first edge radial to said axis and traversing the path of rotation and a second edge nonradial to the axis also traversing the path of rotation and the apparatus further includes means for moving the sensing means so that the position of the sensing means may be adjusted with respect to the first edges which are the leading edges when said indicia are rotated in one direction and to the second edges which are the leading edges when the indicia are rotated in the opposite direction.

The present invention relates to encoders and more particularly to rotational encoders which are useful in closed loop step motor control systems.
In recent years, there has been an increasing demand for high speed step motors in technologies such as high speed printers where step motors are used both in the escapement and character selection apparatus. Open loop control of step motors has the disadvantage that the motor may not be able to follow the input pulse train with sufficient accuracy that the maximum speed which the motor can be operated at is limited. In addition, maximum efficiency cannot be achieved with open loop control. Closed loop step motor systems are directed at overcoming these disadvantages by using positional feedback to the step motor to determine the proper rotor position at which phase switchings of the motor may occur. Thus, closed loop controlled step motor systems appear to be the approach that the field is taking at the present time towards the achievement of higher speed, stability and efficiency in step motor operations. Conventionally, the feedback sensors used in closed loop step motor control systems are optical devices or magnetic devices which provide pulses proportional to the rotation of the step motor.
Conventional encoders used to provide the requisite step motor system feedback may be slotted disks mounted on the shaft of the step motor so as to rotate in synchronization with step motor. Associated with the slotted disk are sensing means comprising a source of light on one side of the disk and a photosensor on the other side for detecting the absence or presence of a slot through the sensing of transmitted light. Of course, in such step motor systems, the position of the photosensor and consequently the timing of the sense pulse with respect to the step position is a very critical aspect of feedback control of the step motor. The slots in the encoder disk are conventionally uniformly spaced and equal in number to the number of steps per revolution of the motor. Consequently, each time a slot passes through the beam from the light source to the photosensor, a pulse is generated by the photosensor and fed back to the control system of the step motor.
In the operation of such encoders, the sensing means are adjusted to a fixed angle which may be referred to as the "lead angle" or the "switching angle" with respect to the detent or equilibrium position of the motor. The lead angle is in effect the number of degrees in advance of (in lead of) a given detent position from which the corresponding phase is sensed and consequently switched. Consequently, the speed of a step motor is directly related to the lead angle.
In the case of some encoders having slots or other rectilinear indicia, the lead angle may be set by adjusting the position of the sensing means or the indicia being sensed with respect to a given motor detent position. In cases where the step motor travels in only one direction, the means for adjusting the position of the sensing means with respect to the leading edges of the slot are relatively straight forward. Usually a single sensing means may be utilized. On the other hand, if the step motor is to be a bidirectional step motor and particularly high speed bidirectional step motor which requires accurate lead angle adjustments in both directions, the problem of lead angle adjustment becomes more complex. It should be noted that where the closed loop feedback system is a common one pulse per step system, i.e., the encoder disk has only one slot per step, it is still very difficult and less than fully accurate to optimize a bidirectional closed loop system. As will be described hereinafter in greater detail with respect to the drawings of the prior art, this is accomplished by positioning each encoder slot at the center equidistant from its two adjacent motor detent positions. This provides an equal lead angle for either direction equivalent to half a step provided the sensing indicia is of negligible width.
However, where the lead angle in either or both directions is to be some value other than a half step, this single sensing means apparatus will be substantially inoperative.
A standard approach in the present technology towards the solution of the above problem is to use dual sensing means, i.e., a first sensor positioned to monitor encoder disk when the step motor shaft is rotating in one direction and a second sensor for monitoring the encoder disk when it is rotating in the reverse direction. However, this approach requires additional equipment and is more complex and expensive than monitoring by a single sensing means.
Similar problems are encountered with linear step motors when such linear step motors are operated in the bidirectional mode.

Encoder for monitoring bidirectional motion

International Business Machines Corporation


A reclosable blister card package is provided, having an insert which rotates inside the blister cavity to present product-holding compartments to the dispensing opening. The insert and blister are cooperatively sized and configured for smooth and efficient rotation of the insert within the blister cavity. Opening features provide the dispensing opening, and reclosure features provide for continuing containment and protection of the unused portion of the product.

Blister packages are beneficial to the merchandizer in that they provide good product visibility, and therefore attract customer attention to the contained product, in addition to providing bulk to the package, thus discouraging theft. Compared to other forms of packaging providing good product visibility, blister packaging is attractively economical. It is believed that initially all blister packages had complete and uniform adhesion around the flange between the blister and the backing board. Normally, the adhesion is very strong, and these packages are thus limited to a one-time use, because either the board or the blister is destroyed when the package is opened. In many cases, though, blister packages could be advantageously used if the package could be opened with minimal package damage, and subsequently reclosed to contain the unused portion of the product. This is particularly advantageous where portions of the contained product are normally removed periodically for use--and the unused portion of the product requires the continuing protection and containment provided by the package.
This invention relates specifically to reclosable blister packages. Reclosable blister packages have been developed which, by various means, allow the package to be opened without substantial package damage, and which provide some reclosing feature. These developments are described in U.S. Pat. Nos. 3,127,010; 3,174,621; 3,502,486; 4,119,203; and 4,166,535. A recent development is described in United States patent application Ser. No. 958,716, filed Nov. 8, 1978, which has now been indicated as allowable.
In the known art of blister packages having a multiplicity of compartments, gaining access to the product in any given compartment requires penetrating the package at the appropriate compartment, normally by tearing. When a number of compartments are involved in the package, the appearance of the torn package may rapidly deteriorate as additional compartments are torn open. There is also the very real risk of inadvertently opening more than one compartment, or the wrong compartment. Thus it would be desirable to provide a reclosable blister package having a multiplicity of product-holding compartments to which access may be gained, separately and individually, through a single opening, and without reducing the capacity of the package to contain product. It would also be desirable if product could be removed from, and subsequently replaced into, individual compartments.
It is therefore an object of this invention to provide a reclosable blister package having a blister cavity which contains multiple product-holding compartments, each compartment being capable of being separately presented to a dispensing opening in the package.
It is a further object to provide such a package having a blister with a product-holding cavity, and a rotatable insert in the cavity, the insert having a multiplicity of product-holding compartments.
It is a more specific object to provide a reclosable blister package having a rotatable insert capable of holding products in a multiplicity of product-holding compartments, inside the blister cavity, and a means for opening the package and presenting the compartments to the opening; and in doing so in such a manner that product may be removed from a given compartment, and subsequently replaced into the same, or a similar compartment; the removal and replacement proceeding without substantially damaging the compartment or the overall package, or reducing its product-holding capacity.

Reclosable dispensing blister card package


An electrical power system includes a transmission line for transmitting electrical power, series capacitance compensation series-coupled to the transmission line adjacent one end thereof, where the series compensation includes a capacitance having a value (xe2x88x92j XCAP), and a protective relay at the one end of the transmission line for monitoring line voltages and line currents on the transmission line. Upon sensing a fault, an impedance Z of the line is calculated based on the monitored line voltages and line currents. The calculated impedance Z is adjusted according to the value of the capacitance of the series compensation (xe2x88x92j XCAP) to result in a modified impedance ZMOD, and the phasor angle Of ZMOD is examined to determine the direction of the sensed fault. The fault is in a first direction if the phasor angle is between X and X+180 degrees and is in a second direction opposite the first direction if the phasor angle is between X+180 and X+360 degrees.

The present invention relates generally to protective relaying in a power transmission and/or distribution system, and more particularly to a method for use in connection with a protective relay or like device to accurately determine fault direction in a capacitance-compensated line of such a power system.
In a power distribution system, electrical transmission lines and power generation equipment must be protected against faults and consequent short circuits. Otherwise, such faults and short circuits can cause a collapse of the system, equipment damage, and/or personal injury. Accordingly, and as shown in FIG. 1, a typical power system employs a protective relay at each end of a transmission line to monitor system conditions on and adjacent such protected transmission line, to sense faults and short circuits on and adjacent such protected line, and to appropriately isolate such faults and short circuits from the remainder of the power system by tripping pre-positioned circuit breakers on such protected line.
As seen, a typical power system can be connected over hundreds of miles and include multiple power generators (generator S, generator R) at different locations. Transmission lines (the main horizontal lines in FIG. 1) distribute power from the generators to secondary lines or buses (the main vertical lines in FIG. 1), and such buses eventually lead to power loads such as motors, houses, office buildings, manufacturing facilities, industrial plants, cities, etc. Importantly, relays and circuit breakers are appropriately positioned at each end of a protected transmission line to perform the isolating function described above.
A modern protective relay typically measures voltage and current waveforms measured at the respective end of a corresponding protected line, and employs a microprocessor and/or digital signal processor (DSP) to process the measured waveforms. As used herein, the term xe2x80x98transmission linexe2x80x99 includes any type of electrical conductor, such as a high power conductor, a feeder, etc. Based on the processed waveforms, the protective relay can then decide whether to trip an associated breaker, thereby isolating a portion of the power system.
In particular, and referring now to FIG. 1A, it is seen that a typical protective relay 10 samples voltage and current waveforms VA, VB, VC, IA, IB, IC from each phase (A-C) of a three phase line 12 at a particular point along such line 12. Of course, the line 12 may have greater or lesser numbers of phases, and greater or lesser numbers of phases in a line 12 may be sampled. The sampled waveforms are stored in a memory 14 and may then be retrieved and appropriately operated on by a processor or DSP 16 to produce estimated voltage, current, and impedance phasors. As should be understood, such phasors merely express such values in complex form according to magnitude and angle. As should also be understood, such impedance phasors in particular are employed to determine whether a fault condition exists, and if so to determine fault direction and estimate fault location, among other things.
Based on the determined fault direction and estimated fault location, then, the relay 10 may decide that a detected fault is on the line 12 protected by such relay 10 or is otherwise within the xe2x80x98zone of protectionxe2x80x99 of such relay 10, and that an associated circuit breaker 18 should be tripped to isolate the faulted line 12. Accordingly, such relay 10 issues an appropriate command to the circuit breaker 10.
Typically, the command is issued over a xe2x80x98TRIPxe2x80x99 output of the relay 10 (xe2x80x98TRIP 1xe2x80x99 in FIG. 1A) and is appropriately received as an input to the circuit breaker 18. The relay 10 may then reset the circuit breaker 18 (by appropriate means) after the relay 10 senses that the fault has been cleared, or after otherwise deciding or being ordered to do so. Notably, the relay 10 may control several circuit breakers 18 (only one being shown in FIG. 1A), hence the xe2x80x98TRIP 2xe2x80x99 output (additional xe2x80x98TRIPxe2x80x99 outputs not being shown in FIG. 1A). Additionally, the circuit breakers 18 may be arranged to control one or more specific phases of the line 12, rather than all of the phases of the line 12. Owing to the relatively large distances over which a power system can extend, the distance between a relay 10 and one or more of its associated circuit breakers 18 can be substantial. As a result, the outputs from the relay 10 may be received by the circuit breaker(s) 18 by way of any reasonable transmission method, including hard wire line, radio transmission, optical link, satellite link, the transmission lines 12 themselves, and the like. Moreover, the commands may be transmitted and received as packetized network signals or the like on a data network rather than as signals on dedicated lines.
As seen in FIGS. 1 and 2, a transmission line, and in particular a relatively long transmission line, is oftentimes series-compensated by the installation of series capacitance 20 in the form of one or more capacitors or banks of capacitors (a representative series capacitor CAP is shown) at or adjacent one end of such line or perhaps even toward the middle of the line. Benefits obtained thereby include increased power transfer capability, improved system stability, reduced system losses, improved voltage regulation, and better power flow regulation. However, such installation of series capacitance 20 introduces challenges to protection systems for both the series-compensated line and lines adjacent thereto.
Typically, and as best seen in FIG. 2, installed series capacitance 20 includes a metal oxide varistor (MOV) or other non-linear protection device in parallel with the series capacitance (CAP), which limits the voltage across the capacitance in a pre-defined manner. Additionally, a bypass breaker or bypass switch (SW) is installed in parallel with the series capacitance, which closes following operation of a series capacitance overload protection system (not shown). The closing of such breaker introduces a transient in the system as the breaker arcs and the impedance seen by the protective relay is altered. In particular, the quick response of the MOV and overload protection (the spark gap (SG) installed in parallel with the series capacitance) removes or reduces the capacitance (CAP) and limits the impact of the transient.
Protection of a power distribution system with one or more series compensated lines is considered to be one of the most difficult tasks both for relay designers and utility engineers. A protective relay should be designed to have a high level of security and dependability. A utility engineer should be able to set the protection properly. However, protection settings depend on prevailing system conditions and system configuration, and both may change significantly if series capacitance is present in the system. In particular, such changes result from, among other things, the fact that series capacitance installed within a power system introduces an impedance that must be taken into account when measuring line impedance. More particular, and as is relevant in the present disclosure, the series capacitance and the fact that such series capacitance can vary must be taken into account during determination of fault direction.
In the present invention, accurate fault direction determination is accomplished by compensating fault direction-detecting elements for added series capacitance. In particular, in the present invention, an electrical power system includes a transmission line for transmitting electrical power, series capacitance compensation series-coupled to the transmission line adjacent one end thereof, where the series compensation includes a capacitance having a value (xe2x88x92j XCAP), and a protective relay at the one end of the transmission line for monitoring line voltages and line currents on the transmission line.
Upon sensing a fault, an impedance Z of the line is calculated based on the monitored line voltages and line currents. The calculated impedance Z is adjusted according to the value of the capacitance of the series compensation (xe2x88x92j XCAP) to result in a modified impedance ZMOD, and the phasor angle of ZMOD is examined to determine the direction of the sensed fault. The fault is in a first direction if the phasor angle is between X and X+180 degrees, and is in a second direction opposite the first direction if the phasor angle is between X+180 and X+360 degrees.

Method and directional element for fault direction determination in a capacitance-compensated line


A number of TDR systems and testing methods are provided that improve the quality and accuracy of information collected when propagating a signal along a length of cable in order to pinpoint specific anomalies. One or more of the TDR systems includes, for example, a computing device, a pulse generator, and at least one capacitive test sensor. The at least one capacitive test sensor transmits/receives pulses to/from a power system component, such as an insulated power cable, in a capacitive manner.

Transmission cables are intended to operate safely and effectively over lifespans exceeding twenty years. However, because of anomalies in the transmission cable due to manufacturing defects, installation errors, localized imperfections, such as insulation breakdown, transmission cables often suffer premature breakdown. Should this occur during a critical period the repercussions in terms of financial losses and customer inconveniences can be quite severe. Therefore, with the ever-increasing number of transmission cables being utilized throughout the world, it is desirable that anomalies such as faults, discharges, cable damage, and splices of transmission cables be located without the necessity of physical tracing and inspection.
A Time Domain Reflectometer (TDR) is one apparatus that can be used to analyze a cable for anomalies, and more specifically, to analyze the cable for changes in cable impedance in order to locate such anomalies. A typical TDR transmits a pulse of electrical energy onto a cable that includes two conductors separated by a dielectric material. When the pulse encounters a change in the impedance of the cable, part of the pulse's energy is reflected back toward the TDR. The amplitude and polarity of this reflection is proportional to the change in impedance. Such reflections are usually displayed in graphical form on the screen of a typical TDR whereby a technician can interpret the results and locate specific cable anomalies. In particular, the time of propagation of the pulse as well as the pulse shape can be used to identify and locate the anomaly along the transmission cable.

On-line time domain reflectometer system


An end connector for a battery in which a set of interleafing battery plates is electrically and mechanically connected with a cast-on element to form a secure attachment with no discontinuities. The preferred embodiment utilizes a set of lead or lead alloy plates having an edge that is immersed into a mold of molten material that forms the end connector.

Batteries typically are constructed with a set of anode plates and a set of interleafing cathode plates, which are spaced apart by separators infused with an electrolyte. The anode plates must be electrically connected to the battery anode terminal, and the cathode plates must be electrically connected to the battery cathode terminal. For the sake of rigidity of the assembled sets of anode and cathode plates, the connection between the plates and the terminals is typically mechanical as well as electrical, and is accomplished with an "end connector" of some type.
This electromechanical attachment of the anode and cathode plates to their respective terminals through end connectors is one of the more labor intensive and fault intensive aspects of battery construction. Ideally, the end connector assembly would rigidly support the plates to help prevent their deformation within the battery case and to resist vibrational damage to the plates and separators. Further, the end connectors should be formed of a material that is readily connectable to both the terminal and to the plates in a manner that assures an easy and dependable electrical and mechanical attachment. It is particularly important that the electrical connection to both the plates and the terminal be of the lowest possible resistance, or at least of a resistance no greater than the resistance in the plates and terminals themselves, so that the impedance of the connection is minimized and the current capacity is maximized.
These goals become extremely important in a battery with extremely thin plates, as described in U.S. Pat. No. 5,047,300, of which this application is a continuation-in-part, and U.S. Pat. No. 5,045,086. Briefly, those applications disclose a rechargeable battery with a mechanical design characterized by very thin anode and cathode plates that may be spirally wound with a electrolyte pasted separator. The resulting wound battery generally has little structural strength and therefore requires extra support from the battery casing. Further, the very thin plates and separators result in a very large number of plates at each end. The large number of plates requires a proportionately large number of labor intensive and failure prone connectors, in comparison to batteries having thicker plates and separators.
The dominant electrical characteristic of the batteries described in the above-mentioned applications is a very high charge and discharge rate. This high charge and discharge rate requires high current carrying capacity in the electrical connection from the plates to the terminals, in order to both carry the load without reducing the charge and discharge rate and also to avoid resistive overheating that could structurally or electrically damage the battery.
The prior art discloses many types of end connectors that are designed to enhance the structural integrity or to minimize the electrical impedance of batteries. For example, U.S. Pat. No. 4,539,273 by Goebel describes a set of plates wound on a spool with an anode flange and a cathode flange. Each plate has a set of connecting tabs spaced along an edge, which is in electrical contact with the appropriate spool flange. The Goebel device does not provide for any secure mechanical connection between the spool flange and the plates. Also, the Goebel device would appear to require a fairly intricate manufacturing process, especially if used on a very thin plate battery having a very long plate edge that would require a large number of connecting tabs.
In U.S. Pat. No. 3,695,935 by Cromer, there is disclosed a spirally wound plate design where the anode plate is wound offset from the cathode plate so that the anode plate edge overhangs one edge of the spiral and the cathode plate edge overhangs the other edge of the spiral. The two overhanging edges are "ruffled". The purpose of the ruffles is said to be to strengthen the edges against damage during manufacturing, to blunt the edges to reduce the potential for injuring manufacturing workmen, and to increase the ohmic contact between the plate and the terminal. The Cromer device still uses an ordinary strap type end connector to join the plates to the terminal.
One of the more common arrangements for electrically connecting the plates to the terminals is shown in U.S. Pat. No. 3,862,861 by McClelland et al. In the McClelland arrangement, the plates include spaced tabs on the plate edge so that the wound plate has a set of tabs protruding from an end. The protruding tabs are then joined together and connected to the terminal. The McClelland arrangement has the problems of difficulty in construction and increased impedance that are typical of the prior art.


A Signal-to-Noise (SN) ratio maintained scanning-condition recalculating unit re-sets a value of a scanning parameter other than an SN ratio included in scanning conditions when the size of a Field Of View (FOV) to be set for a scan is changed, so as to make the SN ratio of an image to be taken under after-change scanning conditions equal to or larger than the SN ratio of an image assumed to be taken under before-change scanning conditions. A scanning-condition edit/scan positioning unit then sets scanning conditions based on the value of the scanning parameter recalculated by the scanning-condition recalculating unit.

1. Field of the Invention
The present invention relates to a magnetic resonance imaging apparatus that images the inside of a subject by using a magnetic resonance phenomenon, and a scanning-condition setting method. The present invention particularly relates to a technology for controlling a scanning parameter so as to make a Signal-to-Noise (SN) ratio of an image to be obtained through a scan constantly higher than a certain value.
2. Description of the Related Art
A magnetic resonance imaging method used by a magnetic resonance imaging apparatus is a method of acquiring chemical and physical microscopic information about a substance by using a magnetic resonance phenomenon. The magnetic resonance phenomenon is a phenomenon that when being placed in a magnetic field, an aggregation of subject nuclear spins resonates with a radio-frequency magnetic field in which each atomic nucleus spins at a particular frequency (resonance frequency) responding to its own unique magnetic moment and an existing magnetic field, and generates a signal (magnetic resonance signal) in a relaxation process.
According to the magnetic resonance imaging apparatus, the Signal-to-Noise (SN) ratio of an image, the spatial resolution, the scan time, or the like depends on, for example, the type of a pulse sequence or a scanning parameter of the pulse sequence, such as a Field Of View (FOV), a scan matrix, the number of acquisition (number of excitation), or a receiving band. For this reason, the MRI apparatus is an apparatus that needs to set especially various scanning conditions among medical devices.
The SN ratio of an image obtained by the magnetic resonance imaging apparatus has a large influence on the image quality of the obtained image. Sometimes an image of a low SN ratio brings about an obstacle to diagnosis, therefore, it needs to obtain an SN ratio constantly higher than a certain value. To secure a stable SN ratio, usually, scanning parameters are preliminarily registered into the apparatus as default scanning conditions with respect to each scan area, each clinical field, or each disease, and then a scan is performed under the scanning conditions every time.
However, because there are individual differences in the sizes of scan subjects (examination subjects), the FOV, the slice thickness, the slab thickness in a case of three-dimensional scanning, and the like need to be adjusted for each scan in accordance with the size of a scan subject, even if almost all of the other parameters can be kept constant. If the adjustment is not performed, aliasing may occur in an image, or a redundant area may be imaged, in some cases.
Although an adjustment of an FOV is often manually performed by an operator, a method of automatically setting an FOV by measuring the size of an examination subject with a system is proposed (for example, see JP-A H3-16851 (KOKOKU)). Usually, when the FOV is changed, a voxel size changes, so that the SN ratio of an image changes along with the change. Consequently, to keep the SN ratio constant, the operator needs to recover the SN ratio by correcting a parameter other than the changed FOV. Therefore, a method is proposed of predicting to what extent the SN ratio changes with respect to a change in a scanning parameter from the value of the scanning parameter before the change and notifying the operator of the predicted change in the SN ratio (for example, see JP-A 2004-357834 (KOKAI)).
However, when changing the FOV, it is not simply found out which parameter and to what extent needs to be changed in order to return the SN ratio to the original value from a change in the SN ratio arising from the change in the FOV. The reason for this is because such conditions vary depending on a functional direction of the FOV (whether a readout direction or a phase encoding direction).
For this reason, an operation of setting scanning conditions in which the same SN ratio is constantly maintained while changing the FOV requires a skill and an understanding of the principles of scanning according to the magnetic resonance imaging method. Such operation is substantially time consuming for an inexperienced operator, and sometimes results in a problem of an extension of a total examination time in some cases.

Magnetic resonance imaging apparatus and scanning-condition setting method


An apparatus and process for thermally de-manufacturing tires and other materials. The apparatus is a retort chamber with various zones in which tires are combusted to provide energy for the thermal depolymerization reaction, depolymerization takes place, and products leave the retort chamber. In one embodiment, the process reacts water with iron present in steel-belted tires to produce hydrogen, which helps to break sulfur-sulfur bonds in vulcanized materials. The water also helps control the temperature of the reaction, which allows for control over the types and relative amounts of the various depolymerization products.

There is a large interest in recycling waste materials, rather than storing them in landfills. This is particularly true with respect to used tires, a post-consumer waste product, and waste materials resulting from tire manufacture, a post-industrial waste product. Combustion of these materials can produce harmful gases, as they include sulfur crosslinks (a process known as vulcanization), which form hydrogen sulfide on combustion.
There are a variety of processes for depolymerizing the rubber in used tires, including those disclosed in EP 0694600 and U.S. Pat. No. 7,628,892. EP 0694600 discloses a process and a plant where used tires are depolymerized at relatively low pressure, and at a temperature between 100 and 135° C., to form gas and liquid products, which are subsequently combusted. The temperature is maintained by introducing water and air in the device.
U.S. Pat. No. 7,628,892 discloses a plant which includes a depolymerizing device, with a substantially cylindrical body, with an upper base, and a lower base. Thermal depolymerization of tires occurs inside the device, and a product mixture exits the device and then enters a phase separator, to separate out liquid products from gaseous products. The phase separator is connected to an aspiration unit, which enables the depolymerizing device to operate at pressures up to 10 mBar lower than atmospheric pressure. The process purportedly produces a carbonaceous fuel product, and a gaseous product which is burned.
The '892 patent also discloses adding calcium oxide to tires, such that, as the rubber in the tires is depolymerized in the presence of steam, the calcium oxide is converted to calcium hydroxide, which then reacts with sulfur, and forms a salt that then mixes with the steel and carbon recovered from the depolymerization process.
It would be advantageous to provide improved devices and processes for thermally de-manufacturing tires and other waste streams, which in some embodiments do not require added calcium salts to react with sulfur used in rubber vulcanization processes, and which allow for desulfurization to occur, if such is desired, outside of the retort chamber.

Apparatus and method for thermally demanufacturing tires and other waste products