US4432556A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piston sealing arrangement for a cryogenic refrigerator
Assignee: United States Department of the Navy
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Filing: 1983-06-01
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Granted: 1984-02-21
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Expires: 2003-06-01
Abstract
Abstract A sealing arrangement for a rectilinear reciprocable piston within a cryoic refrigerator comprising a buffer defined by dual O-rings disposed around the circumference of the piston and containing pressurized gas of the same type as the refrigeration gas. The buffer limits or prevents both the entrance of contaminants and also the escape of the refrigeration gas.
Inventors
- 👤 Geoffrey F. Green
- 👤 James C. Humphrey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:51
CPC Classifications
F; F16; F16J; F16J15/00; F16J15/16; F16J15/40; F25; F25B; F25B9/00; F25B9/14; Y; Y10; Y10S; Y10S277/00; Y10S277/91
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
67 words
A piston sealing arrangement for a cryogenic refrigerator of the type having a piston slidably and concentrically disposed within a cylinder to moveably define a variable volume expansion chamber for cooling a refrigeration gas comprising: dual O-rings disposed around the circumference of the piston to define a buffer therebetween; and means for supplying to the buffer a pressurized gas of the same type as the refrigeration gas.
Claim 2
Dependent Claim
67 words
A piston sealing arrangement for a cryogenic refrigerator of the type having a piston slidably and concentrically disposed within a cylinder to moveably define a variable volume expansion chamber for cooling a refrigeration gas comprising: dual O-rings disposed around the circumference of the piston to define a buffer therebetween; and means for supplying to the buffer a pressurized gas of the same type as the refrigeration gas.
Claim 3
Dependent Claim
35 words
The arrangement as claimed in claim 1, wherein the means for supplying the pressurized gas comprises a surge tank and a gas supply conduit, said gas supply conduit connecting said surge tank to the buffer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |