JPH04194378A - Cryopump - Google Patents

Abstract

PURPOSE:To reduce the number of shield sheets by setting the dimensions of a louver blind type radiant heat shield of a cryopump to the deeper, the longer. CONSTITUTION:A gas molecule flows in an arrow direction from a gap between front heat shield plates 1 of a cryopump. A group of louvers 3 is installed at the symmetrical sides of a main cryopanel 5, and each size L is lengthened so far as going toward a rear heat shield plate 6. A screen plate 4 is set up to the back of the louver group 3. Thus, the number of louver blind type heat shield sheets is reduced and thereby the cost of production is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cryopump that condenses and adsorbs gas molecules on a cryopanel surface cooled to an extremely low temperature and exhausts the gas molecules at high speed.

[Prior Art] As described in Japanese Unexamined Patent Publication No. 169682/1982, a conventional device uses a cryopanel that has been cooled to an extremely low temperature with liquid helium or the like, at a angle substantially perpendicular to the surface of the gas inlet. ,
Multiple sheets are placed at regular intervals. To prevent this cryopanel from being heated by radiation heat emitted from the high temperature on the gas inlet side, a front shield plate cooled with liquid nitrogen is placed on a part of the gas inlet, and on the side of the cryopanel,
It also has a louver blind heat shield cooled with liquid nitrogen.

Gas molecules to be exhausted flow into the cryopump from the inlet between adjacent front shield plates.

Gas molecules are removed by a louver-blind heat shield, etc.
After repeating the collision one or more times, some molecules flow out from the inlet, while others reach the cryopanel and are condensed and adsorbed.

[Problems to be Solved by the Invention] In conventional cryopumps, the length of the louver blinds is the same and the number of louver blinds is large.

An object of the present invention is to reduce the number of louver blind type heat shields.

[Means for Solving the Problems] In order to achieve the above object, the present invention increases the dimensions of the louver blind heat shield as it goes deeper in the depth direction of the cryopanel.

[Function] By increasing the dimensions of the louver blind heat shield toward the depth of the cryopanel,
The distance between the louver blind type heat shields can be increased. Thereby, the number of louver blind type heat shields can be reduced and manufacturing costs can also be reduced.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. Low-temperature front heat shield plate placed on the front of the cryopump
Gas molecules to be exhausted flow into the cryopump from between the two in the direction of the dashed arrow. Three groups of low-temperature louvers are arranged on the left and right sides of the main cryopanel 5, which is at a very low temperature. This louver 3
The groups are installed so that the louver dimensions become longer from the front heat shield plate 1 to the rear heat shield plate 6, and the spacing between the louvers becomes wider in proportion to the length.

Further, behind the louver 3 group, a 4 group of screen plates thermally integrated with the main cryopanel 5 are arranged with a slight gap between the louver 3 group and the louver 3 group, and these are cooled to an extremely low temperature. Furthermore, a screen plate 2 integrated with the main cryopanel 5 is provided behind the front heat shield plate l. Further, a low-temperature rear heat shield plate 6 is installed at the back of the cryopanel.

Cryogenic main cryopanel 2. The screen plate 4 and the screen plate 2 are arranged so as not to be directly visible from the direction of the cryopump inlet. The gas molecules that flowed into the cryopump from the inlet enter the main cryopanel 5. Solidify on screen plates 2 and 4,
Can be adsorbed.

At this time, by increasing the size of the louvers 3, the area where heat rays can be prevented from entering from the outside can be expanded, thereby making it possible to increase the spacing between the louvers. In addition, if the louver near the entrance is long, the probability of passage decreases, so the structure was designed so that the louver becomes longer as it goes deeper.

By implementing this project, it is possible to reduce the number of louver blind type heat shield plates, which has the effect of reducing manufacturing costs.

Next, another embodiment of the present invention will be described with reference to FIG. In this embodiment, the louver 3 and the screen plate 4 are attached obliquely to the main cryopump 5. In addition, louver 3, screen board 4
and the main cryopump can be installed at any angle. Further, the configuration, operation, etc. other than those described above are the same as the example shown in FIG.

〔Effect of the invention〕

According to the present invention, the number of louver blind type heat shields can be reduced, which has the effect of reducing manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the panel arrangement of a cryopump according to an embodiment of the present invention, and FIG. 2 is a sectional view of the panel arrangement of a cryopump according to another embodiment of the invention. 1... Front heat shield plate, 2... Screen plate, 3...
Louver, 4... Screen plate, 5... Main cryopanel,
6... Rear heat -------/- Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. A cryopump consisting of a cryopanel cooled to an extremely low temperature that solidifies and adsorbs gas molecules, and a radiant heat shield plate cooled to a low temperature that protects the cryopanel from radiant heat from high temperatures, comprising: A cryopump characterized in that the dimensions of the blind type radiation heat shield are made longer the further back the main cryopanel is.