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US3737249A
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US
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High flow pump impeller for low net positive suction head and method of designing same
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1970-08-26
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Granted: 1973-06-05
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Expires: 1990-08-26
Abstract
Abstract A centrifugal or axial-flow impeller has its blade elements inclined at a predetermined sweep angle gamma from the perpendicular to the direction of the approaching fluid being pumped. The sweep angle gamma is quite large, being in the inlet region of the impeller typically 45* or more.
Inventors
- 👤 P Cooper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:44
CPC Classifications
F; F04; F04D; F04D3/00; F04D3/02; F04D29/00; F04D29/18; F04D29/22; F04D29/2261; F04D29/2277
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
114 words
The method of predetermining the structural characteristics of a rotatable impeller for a pump, the fluid entering having an absolute inlet velocity V; impeller blade lineal speed of U and the velocity relative to the rotating impeller of W; the vector W being at an angle of Beta relative to U, which method includes the steps of inclining the blade elements in the inlet region i.e., sweeping the blades forwardly or backwardly at an inclined angle gamma such that tangent Beta (cosine gamma ) X (tangent Beta ), thus providing that Beta will be smaller than Beta and the pump impeller will have increased volume rate capabilities at a low net positive suction head.
Claim 2
Independent Claim
114 words
The method of predetermining the structural characteristics of a rotatable impeller for a pump, the fluid entering having an absolute inlet velocity V; impeller blade lineal speed of U and the velocity relative to the rotating impeller of W; the vector W being at an angle of Beta relative to U, which method includes the steps of inclining the blade elements in the inlet region i.e., sweeping the blades forwardly or backwardly at an inclined angle gamma such that tangent Beta (cosine gamma ) X (tangent Beta ), thus providing that Beta will be smaller than Beta and the pump impeller will have increased volume rate capabilities at a low net positive suction head.
Claim 3
Dependent Claim
69 words
The method of predetermining the structural characteristics of a rotatable impeller as defined in claim 1 and further characterized by the step of inclining the blade elements in the inlet region comprising sweeping the blades forwardly or backwardly at a sweep angle gamma of 45* or greater so as to place said blade elements in a highly non-perpendicular relationship relative to the direction of the approaching fluid being pumped.
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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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |