Cryopump

• US 20080184712A1
• Filed: 02/08/2005
• Published: 08/07/2008
• Est. Priority Date: 02/08/2005
• Status: Abandoned Application

• Current Assignee: Shi-Apd Cryogenics Incorporated, Sumitomo Heavy Industries Limited
• Original Assignee: Shi-Apd Cryogenics Incorporated, Sumitomo Heavy Industries Limited
• Inventors: Longsworth, Ralph C.
• Application Number:
  US11/721,723
• Publication Number:
  US 20080184712A1
• Time in Patent Office: Days
• US Class Current: 62/55.5
• CPC Class Codes: F04B 37/085 Regeneration of cryo-pumps
• CPC Class Codes: F25B 9/14 characterised by the cycle used, e.g. Stirling cycle

Abstract

A cryopump cooled by a GM type refrigerator is disclosed in which the cold (second stage) cryopanel(s) are in planes that are pitched parallel to the axis of the expander cylinder; the cold end of the first stage expansion space is close to the point where the expander cylinder enters the vacuum housing that contains the cryopanels; and a drain system removes all the liquid argon and water flowing out through a vent port for two orientations of the cryopump.

Claims

1. A cryopump cooled by a two-stage GM type refrigerator comprising a housing defining a vacuum chamber, a first stage cryopanel and at least one second stage cryopanel located in the housing and an inlet port to the vacuum chamber from the expander cylinder of the refrigerator where the inlet port is located in a plane parallel to the axis of the expander cylinder and where

a] at least one second stage cryopanel is in a plane parallel to the axis of the expander cylinder,

b] the cold end of the first stage expansion space in the vacuum chamber is located close to the point where the expander cylinder enters the vacuum chamber housing containing the cryopanels, and

c] a drain system is configured to remove all the liquid argon and water through a vent port.

2. The refrigerator of claim 1 where the drain system comprises a finned vent valve constructed of a material having high thermal conductivity.

3. The refrigerator of claim 2 where the drain system further comprises an intake manifold and an output manifold for directing air flow over the finned vent valve.

9. A cryopump in accordance with claim 1 in which the cryopump can be mounted horizontally with the inlet up, or vertically with the expander having the second stage heat station up.

10. A cryopump in a vertical orientation in accordance with claim 9 in which the radiation shield of the first stage cryopanel assembly is mounted to the first stage heat station such that liquid flows around the second stage cylinder and all the liquid flows out through the drain port.

4. A cryopump cooled by a GM type refrigerator having a two-stage expander and an inlet to the vacuum chamber that is perpendicular to the axis of the cylinder of the expander comprising a first stage cryopanel assembly

attached to the first stage heat station of the expander, and

enclosing a second stage cryopanel assembly attached to the second stage of the expander,

where the second stage cryopanel assembly consists of flat plates folded over the second stage cylinder of the expander.

5. A cryopump in accordance with claim 4 including an inlet louver consisting of flat plates centered along the axis of the second stage cylinder.

6. A cryopump in accordance with claim 5 in which the inlet louver is spaced apart from the second stage cryopanel assembly by at least 3 cm.

7. A cryopump in accordance with claim 4 in which the first stage heat station is proximate the junction in the vacuum housing assembly between the cryopanel housing and the cylinder housing.

8. A cryopump in accordance with claim 4 in which the first stage cryopanel assembly and the vacuum housing assembly incorporate a port for liquid to drain.

11. In a cryopump cooled by a two stage GM type refrigerator and comprising an expander cylinder assembly, a vacuum housing, 1st stage cryopanel, flat 2nd stage cryopanel, and vent/drain valve where the expander cylinder consists of a warm flange, a 1st stage cylinder, a 1st stage heat station, a 2nd stage cylinder, and a 2nd stage heat station, the improvement wherein the inlet port to the vacuum chamber is in a plane that is parallel to the axis of the expander cylinder assembly.

12. The cryopump of claim 11 where the cold end of the first stage expansion space is close to the point where the expander cylinder enters the vacuum housing that contains the cryopanels.

13. The cryopump of claim 12 further comprising a drain system positioned such that liquid argon and water flow out through a vent port regardless of whether the orientation of the cryopump is vertical or horizontal.

14. The cryopump of claim 13 comprising an inlet louver positioned across a pump inlet port which shields the central portion of the second stage cryopanel.

15. The cryopump of claim 13 comprising a liquid dam positioned such that liquid is prevented from flowing out of the cryopump inlet when the pump is mounted vertically