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US5456574A
Expired / Lapsed
US
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Centrifugal pump with starting stage
Assignee: RTX Corp
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Filing: 1994-12-02
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Granted: 1995-10-10
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Expires: 2014-12-02
Abstract
Abstract A novel centrifugal pumping system is disclosed for supplying fuel to aircraft gas turbines. The system has a common rotor with two different sets of impeller blades on opposite sides. A regenerative/liquid-ring starting pump is located on one side of the rotor, and a centrifugal impeller is located on the other. During engine start-up, the regenerative/liquid-ring pump is capable of priming itself and supplies engine fluid and pressure. The starting pump delivers fuel until the main pump reaches a speed sufficient to provide adequate pressure for fuel delivery. At that time, the starting pump is switched off, via a valving system.
Inventors
- 👤 Brian G. Donnelly
- 👤 Charles E. Reuter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:25
CPC Classifications
F; F04; F04D; F04D9/00; F04D9/04; F04D9/041; F04D9/042; F02; F02C; F02C7/00; F02C7/22; F02C7/236; F04D13/00; F04D13/12; F04D5/00; F04D5/002; F04D9/044; F04D9/048; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
102 words
A centrifugal pumping system for supplying fuel to an aircraft gas turbine, said system comprising: a. a rotor adapted to be driven by the turbine; b. a main-stage pump having a set of centrifugal impeller blades mounted on one side of the rotor; c. a separate regenerative start-stage pump, in the form of a liquid-ring pump, located on an opposite side of the same rotor and having a set of impeller blades mounted thereon; and d. a valving means that opens or closes fluid communication between the start-stage and main-stage pumps, depending upon engine speed, to activate or deactivate the start-stage pump.
Claim 2
Dependent Claim
102 words
A centrifugal pumping system for supplying fuel to an aircraft gas turbine, said system comprising: a. a rotor adapted to be driven by the turbine; b. a main-stage pump having a set of centrifugal impeller blades mounted on one side of the rotor; c. a separate regenerative start-stage pump, in the form of a liquid-ring pump, located on an opposite side of the same rotor and having a set of impeller blades mounted thereon; and d. a valving means that opens or closes fluid communication between the start-stage and main-stage pumps, depending upon engine speed, to activate or deactivate the start-stage pump.
Claim 3
Dependent Claim
38 words
The centrifugal pumping system of claim 1, wherein the valving means comprises a Bypass Regulating and Mode Transfer Valve which limits pressure rise in the regenerative start-stage pump and also selects an operating mode of the pumping system.
Claim 4
Dependent Claim
43 words
The centrifugal pumping system of claim 2, wherein the valving means further comprises a check valve to prevent back flow into the start-stage pump during "run mode" of the gas turbine, in which the main-stage pump operates in lieu of the start-stage pump.
Claim 5
Dependent Claim
59 words
The centrifugal pumping system of claim 3, wherein the valving means further includes a switching piston which straddles a rotor shaft for the pumping system and which, upon receiving an appropriate signal from the Bypass Regulating Mode and Transfer Valve, strokes to either activate or deactivate the regenerative start-stage pump by opening or closing off a starting-stage flow channel.
Claim 6
Dependent Claim
206 words
A centrifugal pumping system for supplying fuel to an aircraft gas turbine, said system comprising: a. a rotor adapted to be driven by the turbine; b. a main stage pump having a set of centrifugal impeller blades mounted on one side of the rotor; c. a separate regenerative/liquid-ring start-stage pump, located on an opposite side of the same rotor and having a set of impeller blades mounted thereon; and d. a valving means that opens or closes fluid communication between the start-stage and main-stage pumps depending upon engine speed, wherein the valving means comprises: i. a Bypass Regulating and Mode Transfer Valve which limits pressure rise in the regenerative start-stage pump and also selects a primary mode, starting mode, or run mode, of the pumping system; ii. a check valve to prevent back flow into the start-stage pump during run mode in which the main-stage pump operates in lieu of the start-stage pump; and iii. a switching piston which straddles a rotor shaft for the rotor and which, upon receiving an appropriate signal from the bypass regulating and mode transfer valve, strokes to either activate or deactivate the regenerative start-stage pump by opening or closing off a starting-stage flow channel that communicates with the start-stage pump.
Claim 7
Dependent Claim
206 words
A centrifugal pumping system for supplying fuel to an aircraft gas turbine, said system comprising: a. a rotor adapted to be driven by the turbine; b. a main stage pump having a set of centrifugal impeller blades mounted on one side of the rotor; c. a separate regenerative/liquid-ring start-stage pump, located on an opposite side of the same rotor and having a set of impeller blades mounted thereon; and d. a valving means that opens or closes fluid communication between the start-stage and main-stage pumps depending upon engine speed, wherein the valving means comprises: i. a Bypass Regulating and Mode Transfer Valve which limits pressure rise in the regenerative start-stage pump and also selects a primary mode, starting mode, or run mode, of the pumping system; ii. a check valve to prevent back flow into the start-stage pump during run mode in which the main-stage pump operates in lieu of the start-stage pump; and iii. a switching piston which straddles a rotor shaft for the rotor and which, upon receiving an appropriate signal from the bypass regulating and mode transfer valve, strokes to either activate or deactivate the regenerative start-stage pump by opening or closing off a starting-stage flow channel that communicates with the start-stage pump.
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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) | 1998-10-09 | 1999-04-10 | 1999-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-09 | 2003-04-10 | 2003-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-09 | 2007-04-10 | 2007-10-10 | $7700.00 | Window Closed / Lapsed |