Valve system for capacity control of a screw compressor and method of manufacturing such valves

- Coltec Industries Inc.
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Claims

2. The lift valve as defined in claim 1, further comprising a double shaft seal means formed between said housing and said shaft for preventing fluid in the compressor from entering said housing and preventing fluid from escaping from said housing.

3. The lift valve as defined in claim 1, further comprising mounting means for mounting said valve housing on the compressor in a predetermined position.

4. The lift valve as defined in claim 1, wherein said valve housing is formed of a single unitary cast.

5. The lift valve as defined in claim 1, wherein said valve surface forms substantially a continuation of an inner surface of said compression chamber when said piston is in a fully extended position.

6. The lift valve as defined in claim 5, wherein said valve surface is a concave surface.

7. The lift valve as defined in claim 1, further comprising an alignment means for maintaining a rotational position of said valve surface with respect to said valve housing.

8. The lift valve as defined in claim 7, wherein said alignment means includes a male stud extending from a base of said valve housing, and a cooperating female receptacle formed in said piston for receiving said stud.

Referenced Cited
U.S. Patent Documents
2778598 January 1957 Bolling, Jr.
3452935 July 1969 Herold
4014510 March 29, 1977 Smith
4227380 October 14, 1980 Laucks et al.
4435139 March 6, 1984 Astberg
4453900 June 12, 1984 Schibbye et al.
4498849 February 12, 1985 Schibbye et al.
4579513 April 1, 1986 Zimmern et al.
4842501 June 27, 1989 Schibbye et al.
4946362 August 7, 1990 Soderlund et al.
5108269 April 28, 1992 Glanvall
Foreign Patent Documents
59-131791 July 1984 JPX
5-18374 January 1993 JPX
8910489 November 1989 WOX
Patent History
Patent number: RE36281
Type: Grant
Filed: Mar 16, 1998
Date of Patent: Aug 24, 1999
Assignee: Coltec Industries Inc. (Charlotte, NC)
Inventors: Jan A. Zuercher (Spanish Fort, AL), John Q. Richardson (Daphne, AL), Arthur R. Legault (Suwanee, GA)
Primary Examiner: John J. Vrablik
Law Firm: Cummings & Lockwood
Application Number: 9/40,268
Classifications
Current U.S. Class: 418/2012; Unitary Piston And Valve (251/63)
International Classification: F04C 1816; F04C 2910; F16K 31363;