Harold Kenneth Davis

US Patent:

43325270, Jun 1, 1982

Filed:

Aug 10, 1979

Appl. No.:

6/065527

Inventors:

Richard J. Moldovan - Avon OH
Harold D. Davis - Ashland OH

Assignee:

Lear Siegler, Inc. - Elyria OH

International Classification:

F04B 4900

US Classification:

417 15

Abstract:

A variable speed centrifugal pump for aircraft fuel systems and the like having the capability of matching fuel flow and pressure to engine requirements throughout a variable flight profile without in-line flow controls and metering devices comprising a unique combination of centrifugal impeller stage and positive displacement pump device which controllingly, drivingly, fluidly couples the impeller to the aircraft engine drive. The positive displacement pump device includes rotating hydraulic displacing input and output members, the latter being driven by the former at a relative speed normally responsive to discharge flow rate of the positive displacement pump device which is controlled to regulate impeller speed for matching pump flow and pressure to engine requirements. The positive displacement pump may employ fuel as the pumping media in which event the discharge flow from the positive displacement pump device may be directed to the main pump outlet during pump priming and engine start-up and, alternately, to a jet nozzle provided in series with the centrifugal impeller stage to provide motive flow therefor under idle and in-flight conditions. During engine prime and start-up, free rotation of the impeller may be restrained by a clutch responsive to impeller discharge pressure to ensure adequate fuel supply delivery by the positive displacement pump device to the engine at low RPM's.