JP3383861B2 - Cryopump and operating method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryopump and a method of operating the same, and more particularly, to a vacuum container for forming a high vacuum and extremely low temperature environment substantially equal to a space environment, such as a space environment test apparatus. The present invention relates to a structure of a cryopump portion provided and an operating method thereof.

[0002]

2. Description of the Related Art In general, a space environment tester (space chamber) simulates the cold darkness of space by installing a heat absorption wall called a shroud or a cryopanel inside a vacuum container (chamber). The inside is evacuated to a high vacuum of 1 × 10 ⁻⁵ or less by using an oil rotary pump, a turbo molecular pump, a cryopump, etc. to simulate a high vacuum in space.

In such a space environment test apparatus,
Contamination of the test object, particularly optical parts of the test object by the so-called contamination of released gas containing oil generated from the organic parts of the test object such as inside the vacuum container and the artificial satellite has become a problem.

For this reason, the space environment test apparatus is provided with a contamination removal panel cooled by liquid nitrogen or the like so as to solidify and solidify the contamination.

In the space environment test apparatus, the shroud and the contamination removal panel are made of liquid nitrogen or the like at the time of the test.
In addition to cooling to 0 K or less, the cryopump is cooled to operate with a low-temperature liquefied gas to remove moisture, nitrogen gas, and air components such as hydrogen.

However, when the shroud is controlled at room temperature or higher to conduct the test, it is necessary to install a shield plate between the shroud and the sample in order to avoid cooling of the sample. In addition, when the shroud is cooled to liquid nitrogen temperature and operated, when returning it to room temperature, the temperature of the shroud should be kept at room temperature in order to avoid the contamination adhering to the contamination removal panel from vaporizing and contaminating the specimen. It is necessary to heat the contamination removal panel after the heating up to is completed and the vacuum container is returned to several Torr or more.

Therefore, in addition to using the cryopump for high-vacuum exhaust, it is conceivable to use the cryopump as a contamination removal panel by solidifying and solidifying the contamination in the cryopump itself.

[0008]

However, when the cryopump is used as a contamination removal panel, since the cryopump is a storage type pump, it is condensed and solidified in the pump after the evacuation is completed. It is necessary to remove the existing contamination, that is, to regenerate it.

The above-mentioned cryopump is regenerated by a temperature raising step of returning the cryopump to a normal temperature, an exhausting step of evacuating the cryopump to discharge contamination to the outside of the system, and a cooling for lowering the cryopump to a temperature required for operation. It is performed according to the process.

That is, the refrigerator is stopped and dry nitrogen gas heated by a heater is introduced into the cryopump, the temperature inside the cryopump is raised to about 5 to 10 ° C., and the temperature rises to solidify and solidify the cryopump. Contamination, mainly water vaporized, was sucked by a vacuum pump and discharged outside the system to regenerate the pump.

However, in this regenerating method, contamination having a saturated vapor pressure lower than that of water at room temperature, for example, DO used as a plasticizer of the organic material of the organic component is used.
P (dioctyl phthalate) and DEP (diethyl phthalate) have a vapor pressure of 7 × 10 ⁻⁶ to 1 × 10 at room temperature.
^{It was -6} Torr, and these substances could not be vaporized sufficiently at the above-mentioned temperature rise to normal temperature, and could not be discharged from the cryopump.

Further, the contamination that has been vaporized during the regenerating process may be diffused again from the cryopump into the vacuum container and adhere to the main body such as an artificial satellite or the optical parts.

Therefore, according to the present invention, when the cryopump is used as a contamination removal panel, the cryopump can be easily and sufficiently regenerated, and the gas generated at the time of regeneration can be prevented from being re-diffused into the vacuum container. It is an object of the present invention to provide a structure of a cryopump part that can be performed and a method of operating the same.

[0014]

In order to achieve the above-mentioned object, the cryopump of the present invention comprises a side wall of a body of a vacuum container.
In a horizontal cryopump that is connected to the mounting hole formed in , and evacuates the inside of the vacuum container, a drain trap is provided on the front surface of the pump body of the cryopump,
Drain drain having a drain valve at the bottom of the drain trap
Connect, with arranging a gate valve between the drain trap and the vacuum container, the pump body portion, and a heater for heating the cryopump than the normal temperature, a vacuum pump, a nitrogen gas inlet tube for purging When, characterized in that a nitrogen purge gas outlet pipe, the method of operation, during evacuation of the vacuum chamber, agglomerated and solidified contamination occurring in the vacuum chamber in the pump body portion,
When the cryopump is regenerated after the evacuation, the gate valve is closed and the pump main body is warmed to room temperature by the heater, and the purge nitrogen gas is introduced into the pump main body from the purge nitrogen gas introduction pipe. with the introduction to the generated gas component discharged entrained in purging nitrogen gas from the nitrogen purge gas outlet pipe, said <br/> generated liquid component within said pump body portion without passing through the pump body portion It is discharged from the bottom of the drain trap , and then the inside of the cryopump is evacuated by the vacuum pump while the pump main body is heated above the room temperature by the heater to remove substances having a low vapor pressure at room temperature from the inside of the cryopump. It is characterized by doing.

[0015]

[Operation] According to the above configuration, it is not necessary to install a shield plate in the vacuum container, and by closing the gate valve during regeneration of the cryopump, the contamination that is vaporized during regeneration is re-diffused into the container. Can be prevented. In addition, if a large amount of contamination, especially liquid that is generated when water is treated, is passed through the pump body.
Instead, it can be discharged from the bottom of the drain trap , and it can be processed in a short time compared to vaporizing the entire amount.

Further, as in the present invention, by performing vacuum evacuation while heating at room temperature or higher, it is possible to sufficiently discharge a substance having a low vapor pressure at room temperature.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail based on an embodiment shown in the drawings.

[0018] First, as shown in FIG. 2, on the inner circumference of the vacuum container 1 space environment testing apparatus, together with the shroud 2 is provided over substantially the entire area, the mounting holes 1a formed in the body portion side walls Is connected to the cryopump 3 in the lateral direction . As in the conventional case, the shroud 2 is cooled to 100 K or less by supplying liquid nitrogen through a pipe (not shown).

As shown in detail in FIG. 1, the cryopump 3 is provided with a drain trap 32 and a gate valve 33 from the pump body 31 side between the pump body 31 and the vacuum container 1. At the bottom of the drain trap 32, the drain valve 32a having a drain valve 32a is connected, and the pump main body 31 has a heater 34, a vacuum pump 35, and a nitrogen purge gas for use during pump regeneration as in the conventional case. A gas inlet pipe 36 and a gas outlet pipe 37 are provided. In the figure, 34a is a power source for the heater, and 34b
Is a control unit.

During normal use, the cryopump 3 is used as a pump for high-vacuum exhaust with the gate valve 33 opened, and at the same time, the contamination on the cooling surface in the pump main body 31 condenses and solidifies the contamination. Also used as a nation removal panel.

When the test object 4 is set in the vacuum container 1 and a test simulating the space environment is performed, the vacuuming (roughing) of the vacuum container 1 is started with the gate valve 33 closed. The inside of the container 1 is depressurized to a predetermined degree of vacuum, and the operation of the cryopump 3 is started. When the cryopump 3 is operated, first, the vacuum pump 35 is operated to open the exhaust valve 35a to evacuate the interior of the cryopump .

When the inside of the cryopump reaches a predetermined degree of vacuum, the exhaust valve 35a is closed to stop the vacuum pump 35, the cryopump 3 is started to start cooling, and the shield 31a and the baffle 31b of the cryopump 3 are turned on. 1
When the temperature becomes 00K or less and the cryosurface 31c becomes 20K or less, the gate valve 33 is opened and the exhaust operation state is set.
The cooling source of the cryopump is various refrigerators or liquefied nitrogen.

As a result, the cryopump 3 functions as a high vacuum exhaust pump, and the contamination generated in the vacuum container is shielded by the shield 31a and the baffle 3.
It functions as a contamination removal panel that removes contaminants generated from the inside of the vacuum container 1 by solidifying and solidifying 1b.

After the experiment is completed, the interior of the vacuum container 1 is heated to normal temperature by keeping the gate valve 33 open.
Contamination generated inside the vacuum container 1 due to this heating can also be collected by the cryopump 3.

Regeneration of the cryopump 3 is performed with the gate valve 33 closed and insulated from the inside of the vacuum container 1.
First, after closing the gate valve and stopping the cryopump 3, the heater 34 is energized, and at the same time, the introduction valve 36a of the purging nitrogen gas introduction pipe 36 is opened to introduce the purging nitrogen gas into the cryopump. The outlet valve 37a of the outlet pipe 37 is opened when the inside becomes atmospheric pressure.

After the temperature of the pump main body 31 is raised to room temperature, for example, 20 ° C., the gas component vaporized by the temperature rise is entrained in the nitrogen gas for purging for a predetermined time, for example, 30 minutes and discharged from the outlet pipe 37 to the outside of the system. To do. At the same time, if necessary
By opening the drain valve 32a of the drain trap 32 on the front surface of the pump body 31 , the liquid component is removed from the pump body 31.
It can be discharged outside the system without passing through .

After the regeneration at the normal temperature for a predetermined time, the inlet valve 36a, the outlet valve 37a and the drain valve 32a are closed,
The inside of the pump is heated to room temperature or higher, for example, 60 ° C., and the vacuum pump 35 is operated to exhaust the inside of the pump.

In the exhaust operation while heating above the room temperature, the contamination components adhering to the cooling panel surface are vaporized by heating and are almost completely discharged, that is, the pump has a predetermined vacuum degree. It is desirable to do it until it arrives. After this, the heater 34 is turned off and the vacuum pump 3
If 5 is stopped, a series of regeneration steps are completed.

By closing the gate valve 33 as described above, the cryopump 3 is irrespective of the state inside the vacuum container 1.
Therefore, it is possible to automatically perform a series of regeneration steps in a short time. Further, since the contamination generated by the regeneration of the cryopump 3 does not return to the inside of the vacuum container 1, the inside of the vacuum container 1 and the DUT 4 are not contaminated.

Further, by discharging the liquid component generated during the regeneration from the drain trap 32, it is possible to significantly reduce the time as compared with the case where the liquid component is vaporized and discharged. In addition, by evacuating the cryopump 33 in a state where it is heated to room temperature or higher, it is possible to sufficiently discharge a substance having a low vapor pressure at room temperature. It can be used in the state of no adherence, and the vacuum evacuation capacity and the contamination removal capacity hardly deteriorate.

[0031]

As described above, in the cryopump of the present invention, since the drain trap and the gate valve are provided between the pump and the container, if the gate valve is closed, the cryopump can be regenerated in the container. It can be done automatically regardless of the state. Further, by discharging the liquid component generated during the regeneration from the drain trap, the regeneration time can be shortened. Furthermore, by vacuum evacuation while heating to room temperature or higher, a substance having a low vapor pressure at room temperature can be sufficiently removed.

Therefore, by using the cryopump of the present invention not only as a pump for high vacuum exhaust of a space environment test apparatus but also for removing contamination, it is not necessary to install a contamination removing panel in the vacuum container. Not only is it unnecessary to install a shield plate, but it is possible to reliably remove contamination in the vacuum container and to prevent contamination of the vacuum container and the DUT during regeneration.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a cryopump of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a cryopump is installed in a vacuum container.

[Explanation of symbols]

1 ... Vacuum container 2 ... Shroud 3 ... Cryopump 31 ... Pump body 32 ... Drain trap
33 ... Gate valve 34 ... Heater 35 ... Vacuum pump 36 ... Purge nitrogen gas inlet pipe 37 ... Purge nitrogen gas outlet pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-294575 (JP, A) JP-A-62-3177 (JP, A) JP-A-62-131982 (JP, A) JP-A-3- 106432 (JP, A) Actual development 62-26576 (JP, U) Actual development 59-81784 (JP, U) Actual public 60-42235 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F04B 37/08 F04B 37/16

Claims (2)

(57) [Claims] 1. A mounting hole formed in a side wall of a body of a vacuum container.
A horizontal cryopump that is connected to a vacuum chamber to evacuate the inside of the vacuum container, the pump body of the cryopump being provided.
The drain trap is provided on the front of the
A heater for connecting a drain vent having a drain valve at the bottom, disposing a gate valve between the drain trap and the vacuum container, and heating the cryopump at room temperature or higher in the pump body. And a vacuum pump, a purge nitrogen gas introduction pipe, and a purge nitrogen gas discharge pipe. 2. A method of operating a cryopump according to claim 1, when the evacuation of the vacuum vessel, the contamination occurring in a vacuum vessel agglomerated and solidified within said pump body portion, after completion of evacuation cryopump regeneration, warmed the pump body portion closes the gate valve to the room temperature by the heater, generated by introducing nitrogen purge gas from the purge nitrogen gas inlet tube into the pump body portion with discharging gas component entrained in the nitrogen purge gas from the purge nitrogen gas outlet pipe, said port
The liquid components generated in the pump body do not pass through the pump body.
The discharged from the bottom portion of the drain trap, then Pont
Operation of the cryopump characterized in that the interior of the cryopump is evacuated by the vacuum pump while heating the main body of the cryopump to a room temperature or higher by the heater, and substances having a low vapor pressure at the room temperature are also removed from the cryopump. Method.