Patent US3620248A successfully refreshed from Google Patents.
US3620248A
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US
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Backpressure device
Assignee: SPX Technologies Inc
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Filing: 1970-07-20
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Granted: 1971-11-16
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Expires: 1990-07-20
Abstract
Abstract The disclosure concerns a device for imposing a back pressure on hydraulic metering pumps. The device includes a plurality of serially arranged, annular orifices defined by peripheral, axially spaced lands on a rigid mandrel, and an encircling, stretched elastomeric sleeve. The preload in the sleeve at each land determines the upstream pressure required to open the orifice and allow flow across the land, and the preloads are controlled by design so that none of the orifices creates a pressure differential which results in damaging cavitation.
Inventors
- 👤 Francis H Cary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:54
CPC Classifications
F; F16; F16K; F16K17/00; F16K17/18; Y; Y10; Y10T; Y10T137/00; Y10T137/6851; Y10T137/6855; Y10T137/6881; Y10T137/6888; Y10T137/7722; Y10T137/7771; Y10T137/7837; Y10T137/7866
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
179 words
Apparatus for producing a back pressure in a fluid stream comprising a. a rigid mandrel (11) formed with a series of axially spaced, annular grooves (21-25) which define a plurality of peripheral lands (26-29); b. an inlet passage (18) for leading fluid into the first groove (21) of the series, and a discharge passage (19) for leading fluid from the last groove (25) of the series; and c. an elastomeric sleeve (12) encircling mandrel (11) and having a stretched portion which overlies the grooves and is held by its internal stresses against the lands, d. the stretched portion being free to lift away from the lands under the action of the pressures in the grooves so that fluid can flow serially through the grooves, and e. the lands and sleeve being so dimensioned that the preload in the sleeve decreases from a maximum at the land (26) adjacent said first groove (21) to a minimum at the land (29) adjacent said last groove (25), f. whereby as fluid flows from groove-to-groove its static pressure decreases in progressively smaller steps.
Claim 2
Dependent Claim
179 words
Apparatus for producing a back pressure in a fluid stream comprising a. a rigid mandrel (11) formed with a series of axially spaced, annular grooves (21-25) which define a plurality of peripheral lands (26-29); b. an inlet passage (18) for leading fluid into the first groove (21) of the series, and a discharge passage (19) for leading fluid from the last groove (25) of the series; and c. an elastomeric sleeve (12) encircling mandrel (11) and having a stretched portion which overlies the grooves and is held by its internal stresses against the lands, d. the stretched portion being free to lift away from the lands under the action of the pressures in the grooves so that fluid can flow serially through the grooves, and e. the lands and sleeve being so dimensioned that the preload in the sleeve decreases from a maximum at the land (26) adjacent said first groove (21) to a minimum at the land (29) adjacent said last groove (25), f. whereby as fluid flows from groove-to-groove its static pressure decreases in progressively smaller steps.
Claim 3
Dependent Claim
41 words
Apparatus as defined in claim 1 in which the preloads in the sleeve (12) at the lands (26-29) are sized to afford a constant ratio of the absolute pressure downstream of each land to the absolute pressure upstream of the land.
Claim 4
Dependent Claim
14 words
Apparatus as defined in claim 2 in which said ratio is greater than 0.55.
Claim 5
Dependent Claim
45 words
Apparatus as defined in claim 1 in which a. the diameters of the lands (26-29) decrease in the direction of flow; and b. the inner peripheral surface of the stretched portion of the sleeve (12) is cylindrical when the sleeve is in the relaxed state.
Claim 6
Dependent Claim
55 words
Apparatus as defined in claim 4 in which a. the sleeve has portions at opposite ends of said stretched portion which are held in sealing engagement with seating portions (13, 14) on the mandrel (11) by clamps (15); and b. the inlet and discharge passages (18,19) extend into the mandrel (11) from its opposite ends.
Claim 7
Dependent Claim
24 words
Apparatus as defined in claim 1 which includes overpressure protection means (33) for limiting said lift of the stretched portion of the sleeve (12).
References Cited (Backward Citations)
US3298391A
Cited
US3164167A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |