AFTERBURNER FUEL MANIFOLD FLOW SENSOR

1,250,693. Jet propulsion plant - reheat fuel control. BENDIX CORP. Nov. 24, 1969 [Dec. 3, 1968], No. 57390/ 69. Heading F1J. The invention relates to a flow responsive apparatus for sensing flow of pressurized fuel to the reheat fuel manifold of a gas turbine engine, the apparatus comprising a fluid-flow responsive member which is adapted to actuate an ignition system control member. A gas turbine engine is shown in Fig. 1 and comprises a reheat fuel manifold 40, a reheat ignition means 64, and a variable area propulsion nozzle 26 comprising flaps 44 movable by actuators 46 under control of a unit 48. Reheat fuel is supplied from tank 52 and pump 53 through line 50, the line containing an on/off valve 62, a filter 60 which provides a pressure drop from P 1 to P i and a metering valve 58, the valves 62, 58 being controlled by control lever 56. The reheat fuel flow sensing device 70 is connected to receive fuel at varying pressures in the line 50, and is connected to control the ignition device 64, also the variable area nozzle control unit 48 through line 247. The device 70 comprises an inlet 74 connected to fuel line 50 upstream of filter 60 at pressure P 1 through line 76, and an inlet 78 connected to fuel line 50 downstream of filter 60 at pressure P i through line 80. Fuel entering inlet 74 passes through filter 86 and duct 90 containing restriction 91 to chamber 92 at pressure P x , the fuel then passing through duct 94 under control of valve 96, 116 to chamber 98 at pressure P' x to the left of piston 100. Fuel at pressure P i entering inlet 78 passes to chamber 106 the chambers 92, 106 being separated by a diaphragm 108 which carries valve 116. The piston 100 is urged to the left against stop 122 by a spring-loaded tappet member 124, 126, 130 the stem portion 124 being slidable in a sleeve 128, and when the piston is moved to the right into contact with stop 138 by pressure P'x the stem 124 engages lever 144 which is pivotally mounted at 150. The chamber 118 to the right of the piston 100 is connected to pressure P 2 through duct 120 from inlet 82 and line 84, P 2 being the fuel pressure in line 50 downstream of metering valve 58. The lever 144 carries at its lower end a valve member 156 which is normally urged to close valve opening 162 by spring 160. Fuel at pressure P r from source 181 is communicated through line 179 to inlet 168, through filter 172 to ducts 170, 176 and restriction 178 to the chamber 166 to the right of stepped piston 164, the