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US4074908A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double acting dynamic seal with E-shaped spring and L-shaped seals
Assignee: United States Department of the Air Force
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Filing: 1977-03-09
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Granted: 1978-02-21
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Expires: 1997-03-09
Abstract
Abstract A relatively small bidirectional polymeric piston seal especially useful for cryogenic refrigerators having an E-shaped metallic spring retainer and two wound spring seal expanders positioned between two L-shaped polymeric seals. The L-shaped design permits the use of conventional tooling with high strength abrasive polymeric compounds while maintaining tighter tolerances during manufacture thereby keeping frictional resistance at a uniform level to produce longer wear life at the required high pressure forces in two directions.
Inventors
- 👤 Stanley E. Spencer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:18
CPC Classifications
F; F16; F16J; F16J15/00; F16J15/16; F16J15/32; F16J15/3204; F16J15/3208; F16J15/56; Y; Y10; Y10S; Y10S277/00; Y10S277/935; Y10S277/936; Y10S277/937; Y10S277/944; Y10S277/945; Y10S277/946
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
160 words
A double acting dynamic piston seal assembly for use with a cryogenic pump and the like, said seal assembly comprising a seal holder, a piston movable through said seal holder, two L-shaped seals positioned around said piston with their vertical legs adjacent the piston, said L-shaped seals having the free end of each vertical leg adjacent the other and the horizontal legs extending outwardly away from said piston, an E-shaped spring retainer positioned between the outwardly extending horizontal legs of said L-shaped seals and said seal holder, the legs of said E-shaped spring retainer extending inwardly toward said piston and engaging the horizontal legs of said L-shaped seals, and a pair of wound spring seal expanders positioned between the inwardly extending legs of said E-shaped spring retainer and between the vertical legs of said L-shaped seals and the upright portion of said E-shaped spring retainer thereby providing a piston seal assembly capable of sealing under the required high pressure conditions.
Claim 2
Dependent Claim
160 words
A double acting dynamic piston seal assembly for use with a cryogenic pump and the like, said seal assembly comprising a seal holder, a piston movable through said seal holder, two L-shaped seals positioned around said piston with their vertical legs adjacent the piston, said L-shaped seals having the free end of each vertical leg adjacent the other and the horizontal legs extending outwardly away from said piston, an E-shaped spring retainer positioned between the outwardly extending horizontal legs of said L-shaped seals and said seal holder, the legs of said E-shaped spring retainer extending inwardly toward said piston and engaging the horizontal legs of said L-shaped seals, and a pair of wound spring seal expanders positioned between the inwardly extending legs of said E-shaped spring retainer and between the vertical legs of said L-shaped seals and the upright portion of said E-shaped spring retainer thereby providing a piston seal assembly capable of sealing under the required high pressure conditions.
Claim 3
Dependent Claim
37 words
The double acting dynamic piston seal assembly defined in claim 1 wherein said L-shaped seals are fabricated of a high strength abrasive polymeric compound to provide longer wear life and keep frictional resistance at a uniform level.
Claim 4
Dependent Claim
23 words
The double acting dynamic piston seal assembly defined in claim 2 wherein said high strength abrasive polymeric compound is 15% glass filled tetrafluoroethylene.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |