JP2004027866A - Cryopump device and operating method of cryopump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cryopump device capable of preventing water solidified on a baffle from being liquefied or vaporized, and enabling efficient operation; and an operating method of a cryopump device. <P>SOLUTION: The cryopump device 10 is composed of a two-stage refrigerator 13 having two cooling stages, a control device 16 controlling the operation of the two-stage refrigerator 13, a vacuum container 17 combined with the two-stage refrigerator, a cryopanel 23 thermally contacting with a second cooling stage 12 in the vacuum container 17, a shield 18 thermally contacting with a first cooling stage 11 in the vacuum container 17, and the baffle 19 combined so as to thermally contact with the shield 18. On the basis of detecting signals of a temperature sensor 21 in the first cooling stage 11 and a temperature sensor 22 of the second cooling stage 12, the operation of the two-stage refrigerator 13 and a compressor 15 is controlled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cryopump device whose operation is controlled by a detection signal from a temperature detecting means and an operation method of the cryopump device.
[0002]
[Prior art]
As a prior art related to the present invention, there is a multi-stage refrigerator disclosed in Japanese Patent Application Laid-Open No. H11-257773. In the multistage refrigerator of FIG. 5, a temperature sensor 51 is provided on the last cooling stage 50. In operating the regenerative refrigerator 54 including the refrigerator cold head 52 and the compressor 53 connected to the refrigerator cold head 52, the temperature of the final cooling stage 50 is set to the target temperature based on the detection signal from the temperature sensor 51. Until the temperature reaches the target temperature, the compressor 53 is set to a large input power to start operation, and after the temperature of the final cooling stage 50 reaches the target temperature, the input power of the compressor 53 is reduced to a level at which the target temperature can be maintained. Drive. After the final-stage cooling stage 50 reaches the target temperature, the operation can be performed in the state of the highest refrigeration efficiency, so that the refrigeration efficiency is higher than when the operation is performed with the input power of the compressor 53 fixed.
[0003]
[Problems to be solved by the invention]
However, when a conventional multi-stage refrigerator is used for a cryopump, control based on a detection signal from a temperature sensor 51 provided in a final-stage cooling stage 50 of the multi-stage refrigerator results in efficient operation as a cryopump. There is a problem that can not be.
[0004]
The cryopanel (see FIG. 1) provided in the last cooling stage of the multistage refrigerator constituting the cryopump device is cooled to 20K or less to condense nitrogen, oxygen, argon and the like. The baffle, which is combined with the shield in thermal contact, is cooled to about 80K and serves mainly to solidify the water vapor contained in the gas and reduce thermal radiation to the cryopanel. The temperature of the baffle depends on the temperature of the cooling stage with which the shield is in thermal contact, since the baffle is in thermal contact with the cooling stage in thermal contact with the shield via the shield.
[0005]
When the temperature of the last-stage cooling stage reaches the target temperature, the operation control is performed so as to reduce the operation load of the multi-stage refrigerator, but when the refrigeration output of the multi-stage refrigerator decreases, the temperature of the cooling stage increases. As the temperature of the cooling stage increases, the temperature of the baffle in thermal contact also increases, and the water solidified in the baffle becomes liquefied or steam, causing the following problem.
[0006]
(1) Vacuum deteriorates because the water solidified in the baffle turns into water vapor. (2) Water vapor solidifies again on the cryopanel and covers the surface of the cryopanel. (3) The water solidified by the baffle melts and drops on the cryopanel, the temperature of the cryopanel rises, and the substances condensed in the cryopanel evaporate, and the degree of vacuum deteriorates (4). When the temperature of the baffle rises, the radiant heat to the cryopanel increases, and the temperature of the final cooling stage rises.The present invention solves the above-mentioned problems, and enables a cryopump device and a cryopump device capable of efficient operation. It is an object to provide a driving method.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 for solving the above-mentioned problem includes a multi-stage refrigerator having a plurality of cooling stages, control means for controlling the operation of the multi-stage refrigerator, and a vacuum combined with the multi-stage refrigerator. A vessel, a cryopanel that is in thermal contact with the final cooling stage in the vacuum vessel, a shield that is in thermal contact with any of the cooling stages in the vacuum vessel, and a baffle that is combined into thermal contact with the shield. , Wherein the operation of the multi-stage refrigerator is controlled based on detection signals from a plurality of temperature detection means. "
[0008]
According to the first aspect of the present invention, by providing a plurality of temperature detecting means, it becomes possible to control the operation of the cryopump apparatus based on the temperature of the final cooling stage and the baffle or a detection signal at a portion correlated with the temperature of the baffle. . When the operating load of the multi-stage refrigerator constituting the cryopump device is reduced, the temperature of the cooling stage that is in thermal contact with the baffle via the shield increases. Even if the temperature of the baffle rises, the water solidified in the baffle becomes liquefied or steam by controlling the operating load of the multi-stage refrigerator before the temperature exceeds the melting temperature of the water solidified in the baffle. Can be prevented.
[0009]
The invention according to claim 2 for solving the above-mentioned problem is characterized in that the temperature detection means is disposed on the cooling stage where the final cooling stage and the shield are in thermal contact with each other. .
[0010]
According to the second aspect of the present invention, the temperature detection means is provided on the cooling stage where the final stage cooling stage and the shield are in thermal contact with each other. Even if the temperature of the baffle is lowered, by controlling the operation load of the multi-stage refrigerator before the temperature of the water solidified in the baffle exceeds the melting temperature, the water solidified in the baffle is prevented from liquefying or becoming steam. it can. By providing the temperature detection means on the cooling stage where the baffle is in thermal contact with the shield via the shield, it is possible to perform control with good responsiveness in accordance with the operation state of the multi-stage refrigerator.
[0011]
The invention according to claim 3 for solving the above-mentioned problem is characterized in that the temperature detecting means is disposed on a final cooling stage and either a shield or a baffle.
[0012]
According to the third aspect of the present invention, as in the first and second aspects of the present invention, the temperature detection means is provided on the last cooling stage and either the shield or the baffle. Even if the operating load is reduced, by increasing the operating load of the multi-stage refrigerator before exceeding the temperature at which the water solidified in the baffle melts, the water solidified in the baffle becomes liquefied or steam. Can be prevented. By setting the mounting position of the temperature detecting means as a shield, the degree of freedom of installation is improved. When the temperature detecting means is provided on the baffle, the temperature of the baffle can be directly detected, so that accurate control can be performed.
[0013]
The invention according to claim 4 for solving the above-mentioned problem is characterized in that the control means controls a plurality of multi-stage refrigerators.
[0014]
According to the fourth aspect of the present invention, when the target device is provided with a plurality of vacuum evacuation chambers, or when a plurality of multistage refrigerators are mounted in one vacuum vessel, a plurality of multistage refrigerators are used. To construct a cryopump device. Even when the operation load of the multi-stage refrigerator is reduced, the operation of the multi-stage refrigerator is performed before the temperature of the water solidified in the baffle exceeds the melting temperature. By performing control to increase the load, it is possible to prevent the water solidified in the baffle from liquefying or becoming steam.
[0015]
The invention according to claim 5 for solving the above-mentioned problem is characterized in that “the first step in which the control means receives the detection signals of the plurality of temperature detection means, and the respective detection signals from the temperature detection means. A second step of calculating a control output, a third step of using only one control output from the respective control outputs as a control output, and a fourth step of controlling the multi-stage refrigerator by the control output of the third step And ".
[0016]
According to the fifth aspect of the present invention, the control means receives the temperature of the final cooling stage and the temperature of the baffle or a detection signal at a portion correlated with the temperature of the baffle in the first step, and the signal received from the temperature detection means in the second step is Calculations such as PID control are performed so as to have a predetermined value, and respective control outputs are calculated. In the third step, the result calculated in the second step is compared, and the one that increases the operating load of the multi-stage refrigerator is the control output of the multi-stage refrigerator, which is output to the multi-stage refrigerator in the fourth step. Therefore, among the control outputs based on the detection signals of the respective temperature detecting means, the control output that increases the operating load of the multi-stage refrigerator is selected as the control output, and the temperature at which the water solidified in the baffle melts is selected. The operation load can be increased and the operation control of the multistage refrigerator can be controlled before the pressure exceeds the limit, and the water solidified in the baffle can be prevented from being liquefied or turned into steam.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a cryopump device of the present invention will be described with reference to the drawings.
[0018]
(1st Embodiment)
FIG. 1 shows a cryopump device 10 according to a first embodiment of the present invention, a two-stage refrigerator 13 (multistage refrigerator) having a 1ST cooling stage 11 and a 2ND cooling stage 12 (final stage cooling stage), and a two-stage refrigerator. A compressor 15 connected to the refrigerating machine 13 and the reciprocating pipe 14, a control device 16 for controlling the two-stage refrigerating machine 13 and the compressor 15, a vacuum vessel 17 combined with the two-stage refrigerating machine 13, A shield 18 in thermal contact with the 1st cooling stage 11 in the vacuum vessel 17, a baffle 19 combined to make thermal contact with the shield 18, a temperature sensor 21 attached to the 1st cooling stage 11, and attached to the 2nd cooling stage 12 And a cryopanel 23 attached to the 2ND cooling stage 12.
[0019]
The two-stage refrigerator 13 is a regenerative GM refrigerator having a two-stage configuration. The refrigerant gas (helium) compressed by the compressor 15 is led to a reciprocating pipe 14 and a regenerator (not shown) in the two-stage refrigerator 13, where it is pre-cooled, and then expanded by an expander (not shown). In order to cool the regenerator and cool the refrigerant gas to be sucked next through the regenerator again, the temperature rises while cooling the regenerator material and returns to room temperature, and then returns to the compressor 15 via the reciprocating pipe 14. With this process as one cycle, cold is generated periodically.
[0020]
The control device 16 receives signals from the temperature sensors 21 and 22, calculates a control output based on the respective detection signals from the temperature sensors 21 and 22, and controls output to the two-stage refrigerator 13 and the compressor 15. Perform Note that in the first embodiment of the present invention, both the two-stage refrigerator 13 and the compressor 15 are controlled by the control device 16, but only one of them may be controlled.
[0021]
The cryopanel 23 is attached to the 2ND cooling stage 12 and is cooled to substantially the same temperature as the 2ND cooling stage 12. The cryopanel 23 is cooled to 20K or less and functions to condense gases such as nitrogen, oxygen, and argon. An activated carbon panel (not shown) is provided inside the cryopanel 23, and mainly serves to adsorb hydrogen, helium, and the like.
[0022]
The baffle 19 is combined so as to be in thermal contact with the shield 18, and the shield 18 is in thermal contact with the 1ST cooling stage 11. Therefore, the cold of the 1ST cooling stage 11 is transmitted to the baffle 19 and cooled to about 80K. The baffle 19 mainly functions to solidify the water vapor contained in the gas and reduce heat radiation to the cryopanel.
[0023]
Next, the operation of the cryopump device 10 according to the first embodiment of the present invention will be described. The vacuum vessel 17 constituting the cryopump device 10 is attached to a vacuum target device (not shown) so as to have a sealing property. When the two-stage refrigerator 13 is operated, gas flows into the vacuum vessel 17 from the vacuum target device. The water vapor contained in the gas is cooled by the baffle 19 and solidified. The gas from which the water vapor has been removed reaches the 2ND cooling stage 12, and nitrogen, oxygen, argon and the like contained in the gas are condensed in the cryopanel 23. Helium, neon, and hydrogen contained in the remaining gas components are adsorbed by an activated carbon panel (not shown) provided on the 2ND cooling stage 12. The gas in the vacuum target device is condensed, sublimated, or adsorbed on the activated carbon panel by the cryopump device 10, so that a vacuum is obtained in the vacuum target device.
[0024]
The controller 16 controls the two-stage refrigerator 13 and the compressor 15 so that the temperature of the 2ND cooling stage 12 can maintain a predetermined temperature (for example, 20K) and the temperature of the 1ST cooling stage 11 can maintain a predetermined temperature (for example, 80K). I do. When the temperature of the temperature sensor 22 provided on the 2ND cooling stage 12 and the temperature of the temperature sensor 21 provided on the 1ST cooling stage 11 fall below a predetermined value, the operating loads of the two-stage refrigerator 13 and the compressor 15 are reduced. The temperature of the temperature sensor 21 provided on the cooling stage 11 or the temperature of the temperature sensor 22 provided on the 2ND cooling stage 12 is likely to rise and exceed a predetermined value (the temperature before water solidified in the baffle liquefies or vaporizes). , The operating loads of the two-stage refrigerator 13 and the compressor 15 are increased.
[0025]
In the first embodiment of the present invention, by providing the temperature sensors 21 and 22 on the 1ST cooling stage 11 and the 2ND cooling stage 12, when the operating load of the two-stage refrigerator 13 is reduced, the cryopanel 23 If the temperature of the baffle 19 is likely to exceed a predetermined value even at the temperature or less, the operation load of the two-stage refrigerator 13 is increased by the control device 16 before the water solidified in the baffle 19 becomes liquefied or steam. The water solidified in the baffle 19 can be prevented from liquefying or becoming steam. Further, by providing the temperature sensor 21 on the 1ST cooling stage 11, even if the operating condition of the two-stage refrigerator 13 fluctuates rapidly, control with good responsiveness is possible.
[0026]
(2nd Embodiment)
FIG. 2 shows a cryopump device 30 according to a second embodiment of the present invention. The difference from the cryopump device 10 according to the first embodiment is that a temperature sensor 21 provided on the 1ST cooling stage 11 is attached to a baffle 19. is there. Other configurations are common to the first embodiment, and the same reference numerals are used for the same parts.
[0027]
By providing the temperature sensor 31 on the baffle 19, as in the first embodiment, even when the operating load of the two-stage refrigerator 13 is reduced, the water solidified in the baffle 19 can be liquefied or turned into steam. Can be prevented. Further, by disposing the temperature sensor 31 on the baffle 19, it is possible to detect an accurate temperature of the baffle 19, so that accurate operation control of the two-stage refrigerator 13 becomes possible. In the second embodiment, the temperature sensor 31 is provided on the baffle 19, but it is also possible to attach the temperature sensor 31 to the shield 18 which is correlated with the temperature of the 1ST cooling stage 11, and in that case, the degree of freedom in installing the temperature sensor 31 is improved. I do.
[0028]
(Third embodiment)
FIG. 3 shows a cryopump device 40 according to a third embodiment of the present invention. The difference from the cryopump device 10 according to the first embodiment is that the operation of two two-stage refrigerators 13 is controlled by one control device. It is. Other configurations are common to the first embodiment, and the same reference numerals are used for the same parts.
[0029]
As in the first embodiment, even when the operating load of the two-stage refrigerator 13 is reduced, water solidified in any one of the baffles 19 that has come into thermal contact with the 1ST cooling stage 11 of the two-stage refrigerator 13 is reduced. Since the operating load of the two-stage refrigerator 13 is increased before liquefaction or water vapor, the water solidified in the baffle 19 can be prevented from liquefaction or water vapor. The two-stage refrigerator 13 is not limited to two, and may be three or more. In the third embodiment, the operation of the two-stage refrigerator 13 of the first embodiment is controlled by one controller, but the cryopump device 30 in which the temperature sensor 31 of the second embodiment is attached to the baffle 19 is applied. You can also.
[0030]
FIG. 4 is a control flow showing an operation method of the cryopump device according to the first to third embodiments of the present invention. In the first step, a detection signal from a temperature sensor 21 provided on the 1ST cooling stage 11 and a detection signal from a temperature sensor 22 provided on the 2ND cooling stage 12 are sent to the control device 16. In the second step, PID calculation is performed so that the detection signal from the temperature sensor 21 and the detection signal from the temperature sensor 22 have predetermined values, and control outputs V1 and V2 are calculated respectively. In the third step, the control outputs V1 and V2 obtained in the second step are compared and calculated, and a large value (a value at which the loads of the two-stage refrigerator 13 and the compressor 15 increase) is compressed by the two-stage refrigerator 13 and the compressor. Control output Vx of the machine 15. In the fourth step, the control output Vx is output to the two-stage refrigerator 13 and the compressor 15 to control the operation.
[0031]
The control output Vx is controlled by the two-stage refrigerator 13 before the gas condensed on the cryopanel 23 or adsorbed on the activated carbon panel is liquefied or vaporized and before the water solidified in the baffle 19 is liquefied or vaporized. , The water solidified in the baffle 19 can be prevented from liquefying or becoming steam.
[0032]
In the control flow of the operation method of the cryopump device shown in FIG. 4, the control output Vx is output to both the two-stage refrigerator 13 and the compressor 15, but only one of them may be controlled. In the second step, the PID calculation is performed so that the detection signal from the temperature sensor 21 and the detection signal from the temperature sensor 22 have predetermined values. However, the PID calculation may be omitted, or other control methods (for example, It is also possible to change to (PI control).
[0033]
【The invention's effect】
The cryopump device of the present invention can prevent the water solidified in the baffle from being liquefied or turned into steam, so that the following problem can be solved.
[0034]
(1) Vacuum deteriorates because the water solidified in the baffle turns into water vapor. (2) Water vapor solidifies again on the cryopanel and covers the surface of the cryopanel. (3) The water solidified by the baffle melts and drops on the cryopanel, the temperature of the cryopanel rises, and the substances condensed in the cryopanel evaporate, and the degree of vacuum deteriorates (4). When the temperature of the baffle rises, radiant heat to the cryopanel increases, and the temperature of the final cooling stage rises. Therefore, it is possible to provide a cryopump device and a method of operating the cryopump device with high operation efficiency.
[Brief description of the drawings]
FIG. 1 is a cryopump device according to a first embodiment of the present invention.
FIG. 2 is a cryopump device according to a second embodiment of the present invention.
FIG. 3 is a cryopump device according to a third embodiment of the present invention.
FIG. 4 is a control flow chart showing an operation method of the cryopump device according to the first to third embodiments of the present invention.
FIG. 5 is a conventional multi-stage refrigerator.
[Explanation of symbols]
10 Cryopump device 11 1ST cooling stage 12 2ND cooling stage (final stage cooling stage)
13 Two-stage refrigerator (multistage refrigerator)
16 control device (control means)
17 vacuum vessel 18 shield 19 baffle 21, 22, 31 temperature sensor (temperature detecting means)
23 Cryopanel V1, V2, Vx control output

Claims (5)

A multi-stage refrigerator having a plurality of cooling stages; a control unit for controlling the operation of the multi-stage refrigerator; a vacuum vessel combined with the multi-stage refrigerator; and a thermal contact with a final-stage cooling stage in the vacuum vessel. A cryopanel, a shield that is in thermal contact with any one of the cooling stages in the vacuum vessel, and a baffle that is combined to make thermal contact with the shield.
A cryopump device, wherein the operation of the multi-stage refrigerator is controlled based on detection signals from a plurality of temperature detecting means. 2. The cryopump device according to claim 1, wherein the temperature detection unit is provided on the cooling stage where the last stage cooling stage is in thermal contact with the shield. 3. 2. The cryopump device according to claim 1, wherein the temperature detection unit is disposed on the last-stage cooling stage and any one of the shield or the baffle. 3. 4. The cryopump device according to claim 1, wherein the control unit controls a plurality of multi-stage refrigerators. A first step in which the control means receives the detection signals of the plurality of temperature detection means, a second step of calculating a control output based on the respective detection signals from the temperature detection means, And a fourth step of controlling the multi-stage refrigerator by the control output of the third step, and a fourth step of controlling the multi-stage refrigerator by the control output of the third step.

Images