GB708732A - Fluid pump and controls therefor - Google Patents

Abstract

708,732. Centrifugal pumps; gas turbine plant. BENDIX AVIATION CORPORATION. June 5, 1951 [June 10, 1950], No. 13351/51. Classes 110(1) and 110(3) [Also in Group XXIX] The admission of driving nuid to a motor driving a centrifugal pump is controlled by a normally closed valve, the opening of which is controlled by a means responsive to an operating condition of the pump. Fuel for the reheat chamber of a jet-propulsion engine is supplied by a centrifugal pump 32 which is driven by an air turbine 34 deriving its air supply from the compressor of the engine by way of an inlet 40, valve 64 and a chamber 46. Air pressure is communicated from the inlet 40 by way of a passage 72 to the interior of a bellows 68, where it acts on the underside of the valve 64 to keep it closed. To put the pump into operation, a starting switch 140 is closed, thereby energizing a solenoid-actuated valve 84 to open a vent 82 to atmosphere. This communicates the interior of the bellows 68 to atmosphere through a restriction 80, causing the valve 64 to open and allow air to flow to the turbine 34. When the starting switch 140 is released, the circuit is kept closed by a holding switch 144 which is operated by a coil 146. After a predetermined time, a thermal switch 142 is opened by a heating coil 148, to break the circuit and stop the turbine. However, if within this time the pump discharge pressure has risen to a predetermined value, it will actuate a pressuresensitive switch 118 to keep the circuit closed. If the pump discharge pressure becomes excessive, it acts, by way of a duct 98, upon the interior of a bellows 88 to move a button 90 upwardly against the valve 64 to reduce the air flow to the turbine. If overspeeding occurs, a centrifugal governor 124 actuates a switch 120 to open the circuit until the speed has reduced sufficiently. The pump is stopped by opening a manually operated switch 145 in series with the holding switch 144.