Cryopump

Abstract

Abstract PURPOSE:To aim at enhancing the usability of a cryopump, by covering the outer surfaces of condensing plates exposed to a discharge hole through a space, with a movable shield plate so that the total area of the exposed surfaces is made variable to control the discharge speed of specified gas molecules in gas to be discharged. CONSTITUTION:A shield plate 10 is composed of an annular disc having its outer edge 10a set along the inner surface of a shield 3 and a through hole 10b through which substantially cylindrical condensing panels 4 pierce. This shield plate 10 is elevated within a space 5 in a pump casing 1 by means of a rod 11 which is extended through the pump casing 1 and the shield 3 and which is driven by, for example, a cylinder. With this arrangement, the total area of the outer surfaces 4a which is exposed to a discharge hole 2 in the shield 3 may be changed so that the pressure, reaching to the outer surface 4, of gas molecules such as, for example, Ar entering into the space 5 and having a low condensating temperature, or the discharge gas speed of the molecules may be controlled, and as well the maximum discharge gas speed may be obtained. Accordingly, a low reaching speed may be obtained in a short time, thereby a highly usable cyropump may be obtained.

Inventors

• 👤 Hiroyuki Yamakawa
• 👤 洋幸 山川

Bibliographic Details