JPH04303186A - Regenerating device for cryopump - Google Patents

Abstract

PURPOSE:To reduce the regenerating time of a cryopump. CONSTITUTION:A heating means controlled by a control means, a roughing means and a purge gas supply means are disposed in the operating space of a cryopump. Output signals of a temperature sensitive means and a vacuum degree detecting means which respectively detect the temperature of a cold head disposed in the operating space and the degree of vacuum of the operating space are directly input to a control means through an A/D converter. Accordingly, the amount of information input to the control means is not limited and the control width can be broadened so as to correspond to the supply of purge gas to the operating space. The head exchange between the heating means and condensed and solidified gas is promoted by the supply of purge gas to the operating space, so that the dissolution of condensed and solidified gas smoothly proceeds so as to reduce the regenerating time of the cryopump.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryopump regeneration device.

0002

2. Description of the Related Art Cryopumps, which are generally storage pumps, require regeneration to discharge condensed and coagulated gas stored in their working space.

That is, during normal operation of the cryopump,
The working space and a space requiring vacuum are communicated via a valve, and gas molecules in the space are made to adhere to a cryopanel disposed within the working space, thereby creating a high degree of vacuum in the space. On the other hand, during regeneration, the valve is closed to isolate the working space from the working space, and by raising the temperature of the working space, the condensed and solidified gas that has adhered to the cryopanel is evaporated and discharged to the outside. After the regeneration is completed, the working space is roughly evacuated, the cryopump is activated, and the valve is opened again to communicate the working space with the space and supply vacuum to the space.

0004

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, the control means for controlling each device of the cryopump uses external thermometers to measure the temperature of the cold head in the working space and the degree of vacuum in the working space. (2 contacts) and vacuum gauge (
Since only two values, T1 and T2, are input as the temperature information of the working space, and only two values, P1 and P2, as the vacuum degree information of the working space are input. Therefore, the regeneration time can be shortened by supplying purge gas to the working space to promote dissolution of the condensed and solidified gas.
In this conventional technology, the degree of vacuum during purge gas supply is P1.
The degree of vacuum is even worse than that of P2, and since P1 and P2 are used for other controls, the control means cannot cope with the purge gas supply method, which poses a problem in shortening the regeneration time.

Therefore, the technical objective of the present invention is to shorten the regeneration time of a cryopump.

[0006]

[Structure of the invention]

[0007]

[Means for Solving the Problems] The technical means of the present invention taken to solve the above-mentioned technical problems of the present invention is to detect the working space and the degree of vacuum of the working space in a cryopump regeneration device. a temperature sensing means for detecting the temperature of a cold head disposed in the working space; a heating means disposed around the working space; and a first valve means connected to the working space. a purge gas supply means connected to the working space via the second valve means, a refrigeration means disposed within the working space, a heating means, a roughing means, a purge gas supply means, and a refrigeration means. The analog signal outputs of the vacuum degree detection means and the temperature sensing means are respectively input to the control means.

[0008]

According to the technical means of the present invention described above, the temperature and vacuum degree of the working space are directly input to the control means via the temperature sensing means and the vacuum degree detection means, respectively.

[0009] Therefore, since the amount of information input to the control means is not limited by the number of contacts, the control range is widened, and it is also possible to cope with the supply of purge gas to the working space. As a result, the regeneration time of the cryopump can be shortened.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

Cryopump regeneration device 10 shown in FIG.
In order to obtain a high vacuum in the space 11, the space 11 is connected to the working space 13 of the cryopump 12 via a valve means (not shown). A cryopanel 16 is disposed in the working space 13 and is thermally coupled to a cold head 15 of a refrigeration means 14 (for example, one utilizing a refrigeration cycle such as a Gifford-McMahon cycle or a reverse Stirling cycle). For example, set the head 15 to 20K.
Cool to a certain degree. Note that 17 indicates a baffle disposed within the working space 13.

A temperature sensing means (for example, a temperature sensor, etc.) 18 is disposed in the cold head 15.
It is now possible to detect the temperature of Further, a degree of vacuum detection means (for example, a piran measuring element, a thermocouple measuring element, etc.) 19 is connected to the working space 13, so that the degree of vacuum in the working space 13 can be detected. As shown in FIG. 2, the analog signal outputs of each means 18 and 19 are amplified by analog signal amplification circuits 20 and 21, respectively, and then converted into digital signals by an A/D converter 22 and sent to the CPU 23 of the control means 24. is input.

The CPU 23 controls temperature contact relays 27 and 27 via a display circuit 25 for driving display means (not shown) provided in the control means 24 (displays temperature, degree of vacuum, etc.) and a peripheral buffer 26. A signal is output to the reproduction output 28.

A heating means 30, such as a heater, is provided on the outer periphery of the vacuum dome 29 that defines the working space 13. Further, the working space 13 includes a valve (first valve means) 3
It is connected to a roughing pump (roughing means) 32 via 1, and also connected to a purge gas source (purge gas supply means) 34 via a valve (second valve means) 33.

The operation of the cryopump regeneration device 10 having the above configuration will be explained below.

In order to obtain a vacuum in the space 11, first, the valve means is opened to communicate the space 11 and the working space 13;
Gas molecules in the space 11 are made to adhere to the cryopanel 16 and the buffer 17 in the working space 13. At this time, the cold head 15 is cooled to about 20K or less by the action of the freezing means 14.

As the adhesion of gas molecules to the cryopanel 16 progresses, the capacity of the cryopump 12 decreases, so regeneration is performed. This will be explained based on the flowcharts of FIGS. 3 to 6. During operation of the cryopump 12, the temperature and degree of vacuum in the working space 13 are constantly detected by the temperature sensing means 18 and the degree of vacuum detection means 19, respectively, and each analog signal is sent to the analog signal amplification circuits 20, 21 and The signal is input to the CPU 24 via the A/D converter 23.

First, the main routine of the regeneration method starts in step S1 shown in FIG. 3, and it is determined in step S2 whether the cryopump (C/P) 12 is in operation. Here, if the cryopump 12 is in operation, it waits for reset in step S3. On the other hand, if the operation of the cryopump 12 is stopped, the process proceeds to step S4 and the heating means (HEATER) 30 is activated to heat the inside of the working space 13.

Next, in step S5, the working space 13
The temperature and working space 1 of the cold head 15 arranged in
Check the degree of vacuum in step 3. Here, either the temperature becomes T1 (for example, 50K) or more by the heating means 30, or the degree of vacuum becomes P1 (for example, 65 Pa) due to the progress of evaporation of the condensed and solidified gas.
Wait until the above conditions are met, and if this condition is met, proceed to step S6.
Proceed to. In this step S6, the roughing pump (RP)
32 is activated.

Next, in step S7, the temperature of the cold head 15 is checked and the temperature is T2 (for example, 29
5K) or more, proceed to step (2), and if it is less than T2, proceed to step S8. At this point, since it is now the early stage of regeneration and the temperature of the cold head 15 has not yet become very high, the process proceeds to step S8, where the valve (PGV) 3
3 is opened, and purge gas consisting of dry nitrogen or the like is supplied from the purge gas source 34 to the working space 13.

[0021] In step S9, the degree of vacuum in the working space 13 is checked, and the system waits until the degree of vacuum reaches P2 (for example, 300 Pa) or more, and when the degree of vacuum reaches P2, the process proceeds to step S1.
0 and close the valve 33. By supplying this purge gas, condensation and
Heat transfer efficiency to the solidified gas increases, promoting condensation and evaporation of the solidified gas.

In step S11, the temperature of the cold head 15 is checked again, and the temperature is T3 (for example, 12
0K) or more and less than T4 (for example, 265K), the process proceeds to step S12, but since it is now the beginning of the regeneration and the temperature within the working space 13 has not yet become very high, the process proceeds to step S13. . This step S1
3, by opening the valve (RV) 31 and communicating the working space 13 with the roughing pump 32, the condensed and coagulated gas that has evaporated into the working space and become a gas is roughly pumped out (that is, from the working space 13). Exclude.

[0023] Then, in step S14, the degree of vacuum in the working space 13 is checked again, and the system waits until the degree of vacuum becomes below P2, and when the degree of vacuum reaches P2, the process proceeds to step S15.
After proceeding to step S16 and maintaining this state for 2.5 minutes, the process proceeds to step S16, where the valve 31 is closed.

While repeating the cycle from step S7 to step S16, if the temperature of the cold head 15 checked in step S11 becomes higher than or equal to T3 and lower than T4, the process proceeds to step S12, and the degree of vacuum is reduced to P2 by supplying purge gas. Hold the above state for 1 minute,
Promotes the dissolution of condensed and solidified gases.

Further, as the temperature rises by repeating the cycle from step S7 to step S16, the control means 24 checks the temperature of the cold head 15 in step S7.
When the temperature exceeds T2, the process proceeds to step (2) shown in FIG. It should be noted that the regeneration of the working space 13 has been substantially completed just before proceeding to step (2), and the condensation and condensation that have adhered to the cryopanel 18 have been completely removed.
Most of the solidified gas has been removed.

Now, in step (2), reproduction confirmation is performed in step S21. This playback confirmation is performed in the playback confirmation subroutine shown in FIG. 5, and in step S51,
First, open the valve 31 and wait until the degree of vacuum in the working space 13, which is checked in step S52, becomes below P3 (for example, 25 Pa), and when the degree of vacuum reaches P3, the process goes to step S5.
Proceed to step 3 and close the valve 31.

Thereafter, in step S54, the degree of vacuum in the working space 13 is checked, and if the degree of vacuum is greater than or equal to P1, an NG signal is returned from step S55 to step S21. On the other hand, if the degree of vacuum is below P1, step S
The process advances to step 56 and waits until this state has elapsed for 5 minutes. However, if the degree of vacuum in the working space 13 becomes equal to or higher than P1 during this 5-minute waiting time, an NG signal is returned from step S55 to step S21. On the other hand, when 5 minutes have passed while the degree of vacuum in the working space 13 is maintained below P1, the process advances from step S56 to step S57, and an OK signal is returned to step S21.

Returning to step S21, if the return signal from the reproduction confirmation subroutine is NG, the process returns to step S21.
After the process goes to step S22 and the heating means 30 is turned off, the process goes to step S21 again to confirm the regeneration. On the other hand, if the return signal is OK, the process proceeds to step S23, where the roughing pump 32 and heating means 30 are turned off, and the process proceeds to step S24.
Turn everything off.

[0029] Since the reproduction is all completed as described above, the CP
U23 outputs a reproduction completion signal in step S25.

Next, the process proceeds to step S26, and if the cryopump 12 is turned off, the process proceeds to step S27, where the degree of vacuum in the working space 13 is checked, and if the degree of vacuum is below P1. If there is, there is no problem and the process returns to step S26. However, the degree of vacuum in the working space 13 deteriorates due to outgas and other causes, and the step S
When the degree of vacuum checked in step 27 becomes equal to or higher than P1, the process proceeds to step S28 to turn off the regeneration completion signal, and the process proceeds to step S29 to turn on the regeneration signal.

Thereafter, in step S30, the system enters a state of waiting for input of a time-up signal, so as to wait until a predetermined time has elapsed since the previous stop of the cryopump 12. When the specified time has elapsed in step S30 and a time-up signal is input, the process proceeds to step S31, where the roughing pump 32 is activated, and the valve 31 is activated in step S32.
is opened to roughly draw out gas molecules in the working space 13.

[0032] Then, in step S33, wait until the degree of vacuum in the working space 13 becomes less than P3.
When the condition is below, the process proceeds to step S34, where this state is maintained for 3 minutes, and then the process proceeds to step S61 shown in FIG. 6, where the valve 31 is closed, and then everything is turned off in step S62.

Next, in step S63, a regeneration completion signal is output, and in step S64, the start of the cryopump 12 is waited for. If the operation of the cryopump 12 is confirmed here, the process advances to step S65, and the regeneration is completed. Turns off the output. Note that if the cryopump 12 is in operation in step S26, the steps S27 to S described above are performed.
34 and steps S61 to S64 are skipped, and the process directly proceeds from step S26 to step S65.

In step S65, the regeneration completion signal is turned off, and the process proceeds to step S66, where the roughing pump 32 is operated, and then, in step S67, the valve 31 is opened. After that, in step S68, wait until the temperature in the working space 13 becomes lower than T5 (for example, 273K), and then
When it becomes 5 or less, the process proceeds to step S69, where the valve 31 is closed, and this state is changed to W (for example, 3) in step S70.
0 minutes) Hold. By closing the valve 31 and operating only the roughing pump 32 for this W minutes, the water vapor sucked into the oil by the roughing pump 32 during regeneration can be discharged to the outside. Thereafter, after stopping the roughing pump 32 in step S71, the CPU 23 ends the execution of the program in step S72.

In this embodiment, the relationships are P2>P1>P3 and T2>T5>T4>T3>T1.

[0036]

As described above, in the present invention, the temperature of the cold head disposed in the working space and the degree of vacuum of the working space can be directly transmitted to the control means via the temperature sensing means and the vacuum degree detecting means. It has been entered. Therefore, since the amount of information input to the control means is not limited by the number of contacts, the control range is widened, and it is possible to cope with the supply of purge gas to the working space. As a result, the purge gas is supplied to the working space, and heat exchange between the heating means and the condensed/solidified gas is promoted, so that the condensed/solidified gas is smoothly melted, and the regeneration time of the cryopump can be shortened.

[Brief explanation of drawings]

FIG. 1: A cryopump regeneration device 10 according to an embodiment of the present invention.
The configuration diagram is shown below.

FIG. 2 shows a block diagram of 24 systems of control means in FIG. 1.

FIG. 3 shows a flowchart (2) of the regeneration method in FIG. 1;

FIG. 4 shows a flowchart (2) of the regeneration method in FIG. 1;

FIG. 5 shows a flowchart of the subroutine in FIG. 4;

FIG. 6 shows a flowchart continued from FIG. 4;

[Explanation of symbols]

10 Cryopump regeneration device, 13. Working space, 14 Refrigeration means, 15 Cold head, 18 Temperature sensing means, 19 Vacuum degree detection means, 24 Control means, 30 heating means, 31 Valve (first valve means), 32 Roughing pump (roughing means), 33 Valve (second valve means), 34 Purge gas source (purge gas supply means).

Claims (1)

[Claims] 1. A working space, a vacuum level detection means for detecting the degree of vacuum in the working space, a temperature sensing means for detecting the temperature of a cold head disposed in the working space, and a vacuum detecting means for detecting the temperature of a cold head disposed in the working space; a heating means disposed, and a first
a roughing means connected via a valve means; a purge gas supply means connected to the working space via a second valve means;
A cooling means disposed in the working space, and a control means for controlling the operation of the heating means, roughing means, purge gas supply means, and freezing means, and an analog of the vacuum degree detection means and temperature sensing means. A cryopump regeneration device, wherein each signal output is input to the control means.