JPH04194376A - Cryopump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 Patent Application Laid-open No. 169682/1982, a conventional device uses a cryopanel with a single flat surface cooled to an extremely low temperature with liquid helium or the like against the gas inlet surface. Multiple pieces are arranged at right angles and at regular intervals. To prevent this cryopanel from being heated from high-temperature parts outside the pump, a front heat shield plate cooled with liquid nitrogen or the like is placed in front of the cryopanel on the gas inlet surface, and A louver-blind heat shield plate, also cooled with liquid nitrogen, is installed. Further, a rear heat shield plate cooled with liquid nitrogen is also provided in the depth direction of the cryopanel, that is, on the rear side of the cryopanel. Gas molecules pass through the gaps between the louvers and collide with the cryopanel, where they are coagulated and adsorbed.

The back of the front heat shield plate, the rear heat shield plate, and
The surface of the louver is black-treated to absorb radiant heat, and the external light is designed to collide with these heat shield plates at least once before reaching the cryopanel.

Gas molecules to be exhausted flow into the cryopump from the gas inlet between the front heat shield plates adjacent to the front of the pump. While the gas molecules collide with the louver or the rear heat shield plate once or several times, some gas molecules flow out from the inlet, and some gas molecules reach the cryopanel and are solidified and adsorbed.

[Problem to be solved by the invention]

In the above-mentioned prior art, the cryopanel is arranged with a flat surface perpendicular to the gas inlet surface, and it is necessary to ensure the dimension in the depth direction of the cryopanel.

An object of the present invention is to reduce the size of this cryopanel in the depth direction, thereby reducing the space factor of the cryopump.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a cryopanel having a flat surface that is inclined with respect to the cryopump inlet surface, or a cryopanel surface that is not a flat surface.

[Function] By making the cryopanel a flat surface that is inclined with respect to the cryopump inlet surface, or a cryopanel surface that is not a flat surface, the exhaust capacity is the same, but the gas inlet surface is perpendicular to the cryopanel depth direction. The length can be shortened, reducing the volume and dimensions of the entire cryopump.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG. Low-temperature front heat shield plate 1 placed on the front of the cryopump
Gas molecules to be evacuated flow into the cryopump from between the two in the direction of the dashed arrow. The cryogenic main cryopanel 2,
The angle α is 90 with respect to the cryopump gas molecule inlet plane.
It is inclined by decreasing the size from ' to Oo, and is arranged behind the front heat shield plate l, and three groups of low-temperature louvers are provided on the left and right sides thereof. A screen plate 4 is provided on the B side of the louver, separated from the louver 3 by a slight gap, and thermally integrated with the main cryopanel 2, and is cooled to an extremely low temperature. A screen plate 5 integrated with the main cryopanel 2 is also arranged behind the heat shield plate 1. Further, a low-temperature rear heat shield plate 6 is provided behind the pump in the depth direction.

Cryogenic main cryopanel 2. The screen plate 4 and the screen plate 5 are arranged so as not to be directly visible from the direction of the cryopump inlet. Gas molecules flowing into the cryopump from the inlet can be coagulated and adsorbed by the main cryopanel and the screen plates 4 and 5, and some gas molecules flow out from the cryopump inlet.

At this time, the distance between the control surface heat shield plate 1 and the rear surface heat shield plate 6 can be shortened by reducing the angle α.

FIG. 2 shows another embodiment of the present invention, in which the main cryopanel 2 is shaped like a 7-shape to shorten its dimensions with respect to the cryopump inlet face.

In this case, the rear heat shield plate 6 does not need to be attached to the entire surface along the cryopump inlet surface.

[Effects of the Invention] According to the present invention, the distance between the front heat shield plate and the rear heat shield can be reduced, which has the effect of improving the space factor of the cryopump.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a panel arrangement of a cryopump explaining one embodiment of the present invention, and FIG. 2 is a partial sectional view of a panel arrangement according to another example.

Claims (1)

[Claims] 1. A cryopump consisting of a cryopanel cooled to an extremely low temperature that condenses and adsorbs gas molecules, and a radiation heat shield plate cooled to a low temperature that protects the cryopanel from radiation heat from high temperatures, A cryopump characterized in that the cryopump does not have a flat surface perpendicular to the inlet of the cryopump.