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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 sta

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. Alternatively, other hydraulic fluid may be used as the pumping media for the positive displacement pump, and an auxiliary start pump provided for use during pump prime and engine start-up.

대표청구항 ▼

A variable speed, variable output pump for an aircraft fuel system comprising a housing having a main inlet and a main outlet, a jet pump nozzle downstream of said main inlet, an impeller downstream of said jet nozzle and in fluid series therewith, positive displacement pump means for controllingly,

A variable speed, variable output pump for an aircraft fuel system comprising a housing having a main inlet and a main outlet, a jet pump nozzle downstream of said main inlet, an impeller downstream of said jet nozzle and in fluid series therewith, positive displacement pump means for controllingly, drivingly connecting said impeller to the aircraft engine, the speed of said impeller relative to engine speed being variable in response to the discharge flow rate of said pump means, and valve means for controlling the discharge flow rate of said pump means thereby to vary impeller speed relative to the engine speed and for directing discharge flow of said pump means to said main outlet and to said jet nozzle to provide motive flow therefor.