JP4927642B2 - Operation control method for two-stage refrigerator, operation control method for cryopump using two-stage refrigerator, two-stage refrigerator and cryopump - Google Patents

Description

The present invention relates to an operation control method for a two-stage refrigerator , a cryopump operation control method for trapping and exhausting gas molecules by condensation or adsorption, using a cryogenic surface cooled by the two-stage refrigerator , The present invention relates to a stage refrigerator and a cryopump .

  For the cryopump, a two-stage refrigerator having a first cooling stage having a large refrigerating capacity and a second cooling stage having a refrigerating capacity smaller than that of the first cooling stage is used.

  On the other hand, it is known that the operation of a two-stage refrigerator is controlled by detecting the temperature of a second cooling stage. That is, the input power to the compressor of the two-stage refrigerator can be increased until the temperature of the second cooling stage reaches the target temperature, and the target temperature can be maintained after the temperature of the second cooling stage reaches the target temperature. It is known to drive down to a level to improve driving efficiency (see Patent Document 1).

JP-A-11-257773

  By the way, the refrigerating capacity of the first and second cooling stages of the two-stage refrigerator and the balance between them are determined by the expansion space volumes of the first and second cooling stages and the amount of the regenerator material set at the time of design.

  On the other hand, the size and ratio of the thermal load applied to the first and second cooling stages of the two-stage refrigerator used in the cryopump is the size and structure of the cryopump, installation conditions, heat input from the chamber to be evacuated, process It varies depending on the usage environment such as gas type and flow rate.

  When the above-described conventional operation control is applied to the two-stage refrigerator of the cryopump, since the control is performed based on the temperature of the second cooling stage, there is a problem that the temperature of the first cooling stage cannot be controlled to a necessary temperature. . For example, if the temperature of the radiation shield or louver (baffle) connected to the first cooling stage is too low, argon or nitrogen that should be condensed and exhausted by the cryopanel temporarily condenses on the radiation shield or louver. As a result, the exhaust efficiency decreases. Further, if the temperature of the first cooling stage is too high, moisture is solidified by the cryopanel and covers the surface, and the exhaust capacity of argon, nitrogen, etc. that should be condensed and exhausted by the cryopanel is reduced.

  The above problem can be solved by controlling the temperature of the first cooling stage as a reference. In particular, if you control the inverter built in the drive power supply of the cryopump and adjust the drive power frequency to run the refrigeration cycle as much as necessary to keep the first cooling stage at a constant target temperature The power consumption can be suppressed by minimizing the consumption of high-pressure helium gas.

  However, depending on the usage environment, when the drive power frequency of the two-stage refrigerator is controlled so that the temperature of the first cooling stage is constant, even if the minimum drive power frequency that can be operated is set, It may not be possible to raise the temperature to the target temperature. Further, depending on the use environment, the cooling capacity of the second cooling stage is insufficient, and the temperature of the second cooling stage cannot be lowered to the target temperature.

  An object of the present invention is to solve the above-mentioned problem when the driving power frequency of a two-stage refrigerator is controlled based on the temperature of the first cooling stage to increase the operating efficiency of the cryopump. That is, an object of the present invention is to make it possible to cope with the case where the temperature of the first cooling stage cannot be raised to the target temperature even with the minimum drive power frequency that can be operated.

An operation control method for a two-stage refrigerator according to the present invention includes a first cooling stage and a second cooling stage, a first temperature sensor that detects the temperature of the first cooling stage, and a temperature of the second cooling stage. In an operation control method for a two-stage refrigerator having a second temperature sensor that performs heating means for heating the first cooling stage,
Before SL so that the temperature of the first cooling stage to maintain the target temperature of the first cooling stage, controls the driving power supply frequency of the two-stage refrigerator,
When the temperature of the second cooling stage becomes higher than the target temperature of the second cooling stage, the operation of the heating means is controlled to raise the temperature of the first cooling stage, thereby increasing the drive power supply frequency. The temperature of the second cooling stage is lowered .
The cryopump operation control method of the present invention includes a first cooling stage and a second cooling stage, a first temperature sensor for detecting the temperature of the first cooling stage, and a second for detecting the temperature of the second cooling stage. In an operation control method of a cryopump using a two-stage refrigerator having a temperature sensor and a heating means for heating the first cooling stage,
The operation of the cryopump is controlled by controlling the two-stage refrigerator with the operation control method for the two-stage refrigerator according to the present invention .
The two-stage refrigerator of the present invention is a two-stage refrigerator,
A first cooling stage;
A second cooling stage;
A first temperature sensor for detecting the temperature of the first cooling stage;
A second temperature sensor for detecting the temperature of the second cooling stage;
Heating means for heating the first cooling stage;
A heating controller for controlling the operation of the heating means according to the temperature of the second cooling stage detected by the second temperature sensor ;
An inverter for controlling the drive power supply frequency of the two-stage refrigerator , and
The inverter controls the driving power frequency of the two-stage refrigerator so as to maintain the target temperature of the first cooling stage,
The heating controller controls the operation of the heating means when the temperature of the second cooling stage becomes higher than the target temperature of the second cooling stage, and raises the temperature of the first cooling stage, thereby driving the driving The power supply frequency is increased to lower the temperature of the second cooling stage .
Furthermore, the cryopump of the present invention includes the two-stage refrigerator according to the present invention .

  According to the present invention, even if the temperature of the first cooling stage does not rise to the target temperature even when the drive power supply frequency of the two-stage refrigerator is lowered to the minimum operable frequency, the first cooling stage is heated. The temperature of the first cooling stage can be raised to the target temperature. Therefore, even in a use environment where the temperature of the first cooling stage is unlikely to rise, an operation can be performed in which the temperature of the first cooling stage is maintained at the target temperature. Moreover, it becomes possible to set the target temperature of the first cooling stage in a wide range.

  Hereinafter, the present invention will be further described with reference to the drawings.

  FIG. 1 is a schematic diagram of a cryopump according to the present invention including a control unit for carrying out the control method according to the present invention.

  In the figure, 1 is a cryopump main body, 2 is a two-stage refrigerator, 3 is a compressor, 4 is a drive power supply, and 5 is an inverter built in the drive power supply 4.

  The two-stage refrigerator 2 provided in the cryopump main body 1 includes a first cooling stage 6 having a large refrigerating capacity and a second cooling stage 7 having a refrigerating capacity smaller than that of the first cooling stage. A cryopanel 8 that is cooled to an extremely low temperature by the second cooling stage 7 is connected to the second cooling stage 7. The first cooling stage 6 is connected to a radiation shield 9 that surrounds the second cooling stage 7 and the cryopanel 8 and is cooled to an extremely low temperature by the first cooling stage 6. A louver 10 that is cooled to an extremely low temperature by the first cooling stage 6 through the radiation shield 9 is provided in the upper opening of the radiation shield 9. Furthermore, a casing 11 is provided so as to surround the outside of the radiation shield.

  The first cooling stage 6 of the two-stage refrigerator 2 is provided with an electric heater 12 for heating the first cooling stage 6 and a first temperature sensor 13 for detecting the temperature of the first cooling stage 6. . The second cooling stage 7 is provided with a second temperature sensor 14 for detecting the temperature of the second cooling stage.

  The compressor 3 is connected to the two-stage refrigerator 2 through a high-pressure hose 15. The high-pressure helium gas compressed by the compressor 3 is supplied to the two-stage refrigerator 2 and expanded in a first expansion chamber and a second expansion chamber (not shown) to cool the first and second cooling stages. After that, it is to be refluxed.

  The two-stage refrigerator 2 and the compressor 3 are each connected to a drive power supply 4. The two-stage refrigerator 2 and the compressor 3 are driven by a drive power supplied via a drive power supply 4, and the drive power frequency is controlled by a built-in inverter 5. It has become. The inverter 5 drives the two-stage refrigerator 2 and the compressor 3 with a driving power source having a frequency within a range set in a range where each can be driven.

  The first and second temperature sensors 13, 14 are connected to connections 16, 17 to the first and second temperature setting / controller, respectively.

  A target temperature of the first cooling stage 6 is set in the first temperature setting / controller 16. The first temperature setting / controlling device 16 controls the inverter 5 of the driving power supply 4 based on the temperature detected by the first temperature sensor 13 and the set target temperature of the first cooling stage 6. The temperature data is transmitted to the heating controller 18. Further, the target temperature of the second cooling stage 7 is set in the second temperature setting / controller 17. The second temperature setting / control device 17 transmits temperature data to the heating controller 18 based on the temperature detected by the second temperature sensor 14 and the set target temperature of the second cooling stage 7. The heating controller 18 is connected to the heating power supply 19, and “ON” and “OFF” of the heating power supply 19 are based on the temperature data from the first and second temperature setting / control devices 16 and 17. And the operation of the electric heater 12 connected to the heating power supply 19 is controlled.

  More specifically, the first temperature setting / controlling unit 16 controls the inverter 5 of the drive power supply 4 so that the temperature of the first cooling stage 6 detected by the first temperature sensor 13 maintains the set target temperature. Control to adjust the drive power supply frequency. When the temperature of the first cooling stage 6 is higher than the target temperature, the drive power supply frequency is raised within the frequency range set in the driveable range. When the drive power supply frequency is raised, the refrigeration cycle is accelerated and the temperature of the first cooling stage 6 can be lowered. Further, when the temperature of the first cooling stage 6 is lower than the target temperature, the drive power supply frequency is lowered within the frequency range set in the driveable range. When the drive power supply frequency is lowered, the refrigeration cycle is delayed and the temperature of the first cooling stage 6 rises.

  It is sufficient to raise and lower the drive power supply frequency at least with respect to the drive power supply frequency of the two-stage refrigerator 2. However, in order to enhance the switching effect of the drive power supply frequency, the two-stage refrigerator 2 and the compressor 3 It is preferable to carry out with respect to both drive power supply frequencies.

By the way, depending on the usage environment of the cryopump, the temperature of the first cooling stage 6 may not rise to the target temperature even if the drive power supply frequency is set to the minimum value of the frequency set within the driveable range. The heating controller 18 indicates that the temperature of the first cooling stage 6 has risen to the target temperature even after the temperature data from the first temperature setting / controller 16 has passed the predetermined time after the drive power supply frequency has been lowered to the minimum value. When it indicates that there is not, the heating power supply 19 is turned “ON”. Thereby, the electric heater 12 operates to heat the first cooling stage 6 and raise the temperature to the target temperature. When the heating controller 18 detects from the temperature data from the first temperature setting / controller 16 that the first cooling stage 6 has been heated to the target temperature, it sends a signal to the heating power supply 19 again, and the heating power supply 19 The supply device 19 is switched to “OFF”.

On the other hand, depending on the usage environment of the cryopump, the cooling capacity of the second cooling stage 7 may be insufficient, and the temperature of the second cooling stage 7 may not be lowered to the target temperature. When the temperature data from the second temperature setting / control unit 17 indicates that the temperature of the second cooling stage 7 has not decreased to the target temperature, the heating controller 18 turns on the heating power supply 19. And As a result, the electric heater 12 operates to heat the first cooling stage 6 and the temperature of the first cooling stage 6 rises above the target temperature. Then, the first temperature setting / controller 16 that has detected this controls the inverter 5 to raise the drive power supply frequency within the frequency range set in the driveable range, thereby accelerating the refrigeration cycle, The temperature of the 2nd cooling stage 7 falls, and it can approach target temperature. Heating controller 18, the temperature data from the second temperature setting and control unit 17, the second cooling stage 7 detects that the temperature was lowered to the target temperature, it sends a signal to the heating power supply 19 again, the heating power supply The device 19 is switched to “OFF”.

  The temperature control of the second cooling stage 7 is preferably performed when the temperature of the first cooling stage 6 is the target temperature so as not to greatly disturb the temperature of the first cooling stage 6. . Further, when the difference between the temperature of the first cooling stage 6 and the target temperature reaches a predetermined temperature difference so that the temperature of the first cooling stage 6 does not greatly deviate from the target temperature, the heating power supply 19 is turned on. It is preferable to switch to “OFF”.

  In the above example, the electric heater 12 is used as the heating means of the first cooling stage 6, but the heating means of the first cooling stage 6 is switching between heat transfer and thermal insulation with a high temperature part by a thermal switch, Adjustment of circulating heat input by installation of piping through which helium gas circulates, induction heating, etc. can also be used.

It is a schematic diagram of the cryopump which concerns on this invention including the control part for implementing the control method concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cryo-pump body 2 Two-stage refrigerator 3 Compressor 4 Drive power supply 5 Inverter 6 First cooling stage 7 Second cooling stage 8 Cryo panel 9 Radiation shield 10 Louver 11 Casing 12 Electric heater 13 First temperature sensor 14 First Two temperature sensor 15 High pressure hose 16 First temperature setting / control device 17 Second temperature setting / control device 18 Heating controller 19 Heating power supply device

Claims (8)

A first cooling stage, a second cooling stage, a first temperature sensor for detecting the temperature of the first cooling stage, a second temperature sensor for detecting the temperature of the second cooling stage, and heating the first cooling stage In an operation control method of a two-stage refrigerator having a heating means for
Before SL so that the temperature of the first cooling stage to maintain the target temperature of the first cooling stage, controls the driving power supply frequency of the two-stage refrigerator,
When the temperature of the second cooling stage becomes higher than the target temperature of the second cooling stage, the operation of the heating means is controlled to raise the temperature of the first cooling stage, thereby increasing the drive power supply frequency. An operation control method for a two-stage refrigerator, wherein the temperature of the second cooling stage is lowered . When the temperature of the second cooling stage becomes higher than the target temperature of the second cooling stage, the heating means is turned on, and the temperature of the second cooling stage is increased by increasing the drive power frequency. The operation control method for a two-stage refrigerator according to claim 1 , wherein the heating means is switched off when the temperature is lowered to a target temperature . On and off the heating means, on the electric heater and off, and on the thermal switch for switching the heat transfer and thermal insulation between the hot part off, and on the regulator of the circulating heat through the establishment of circulation piping of the helium gas 3. The operation control method for a two-stage refrigerator according to claim 2 , wherein the operation is turned off or the induction heating device is turned on and off. A first cooling stage, a second cooling stage, a first temperature sensor for detecting the temperature of the first cooling stage, a second temperature sensor for detecting the temperature of the second cooling stage, and heating the first cooling stage In a cryopump operation control method using a two-stage refrigerator having a heating means for
The operation control method of a cryopump characterized by controlling operation of a cryopump by controlling the said two-stage refrigerator with the operation control method of any one of Claims 1-3. A two-stage refrigerator,
A first cooling stage;
A second cooling stage;
A first temperature sensor for detecting the temperature of the first cooling stage;
A second temperature sensor for detecting the temperature of the second cooling stage;
Heating means for heating the first cooling stage;
A heating controller for controlling the operation of the heating means according to the temperature of the second cooling stage detected by the second temperature sensor ;
An inverter for controlling the drive power supply frequency of the two-stage refrigerator , and
The inverter controls the driving power frequency of the two-stage refrigerator so as to maintain the target temperature of the first cooling stage,
The heating controller controls the operation of the heating means when the temperature of the second cooling stage becomes higher than the target temperature of the second cooling stage, and raises the temperature of the first cooling stage, thereby driving the driving A two-stage refrigerator having a power supply frequency increased to lower the temperature of the second cooling stage . The heating controller turns on the heating means when the temperature of the second cooling stage becomes higher than the target temperature of the second cooling stage, and the temperature of the second cooling stage is increased by increasing the drive power supply frequency. The two-stage refrigerator according to claim 5, wherein when the temperature is lowered to a target temperature of the second cooling stage, the heating means is switched off .   The heating means is an electric heater, a heat switch for switching between heat transfer and heat insulation with a high-temperature part, a regulator for circulating heat by installing a circulation pipe for helium gas, or an induction heating device. 6. A two-stage refrigerator as described in 6.   A cryopump having the two-stage refrigerator according to any one of claims 5 to 7.

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