Patent GB-1071244-A (GB)
Title: Afterburner fuel control apparatus for a gas turbine engine
IPC: F02K1/16
Filed: 1964-08-05
Abstract: 1,071,244. Gas turbine jet engine fuel systems. BENDIX CORPORATION. Aug. 5, 1964 [Sept. 13, 1963], No. 46029/66. Divided out of 1, 071, 241. Headings F1G and F1J. [Also in Division G3] In a reheat fuel control apparatus for a gas turbine jet engine having a plurality of fuel manifolds supplied by separate conduits, the fuel flow in each conduit is controlled firstly by a variable area metering valve 434 responsive to the position of the control lever and to first and second variable conditions of engine operation, secondly by a throttling valve 335 which is adapted to control the fuel pressure drop across the variable area metering valve, and thirdly by a fuel shut-off valve 338 which is operative to block the fuel flow towards the associated fuel manifold according to the position of actuating means responsive to the position of the control lever for actuating the plurality of shut-off valves, control means operatively connected to said actuating means being provided to control movement thereof in a series of steps so as to cause the shut-off valves to open in sequential order. The first and second conditions of engine operation referred to are compressor inlet air temperature T 1  operative on bellows 409 and compressor discharge pressure P c  operative on bellows 420. The bellows 409 controls the axial position of the shaft 403 on which are mounted three three-dimensional cams 402, 451, 452, while the bellows 420 controls the axial positions of the followers 394 which are mounted for axial movement on shaft 393. The reheat fuel is supplied either from a first low capacity pump 77' Fig. 5 or from a second high capacity pump 60 Fig. 4, the inlet of the latter pump being controlled by a valve 345 which is urged to its open position in response to a predetermined value of the rate of fuel passing to the separate conduits. The fuel pressure differential is that across a restriction 366 in a duct 365' in parallel with the pressure regulating valve 333, the pressures upstream and downstream of the restriction being communicated to the diaphragm 362 which controls the position of the servo-vent valve 359 and which closes off the line 354 to drain whereby the pressure in chamber 352 increases so that the piston 351 moves downwardly and the valve 349 integral with the piston 351 moves to the open position shown whereby servo-fluid passes through line 350 to open the control valve 345. The sequential opening of the shut-off valves 338 is effected by the valve 622 Fig. 5 which moves upward in stops so connecting first the line 449, then the line 625 and then the line 626 to drain pressure whereby the shut-off valves 338 open in sequence - the second and third shut-off valves are not shown but are disposed in the boxes 341, 342 respectively. The valve 622 is connected to the valve member 563 which is integral with the servo-piston 557 which is caused to move upwardly in steps by the action of the lever 547 which is pivotally connected at its right-hand end to pivotally mounted lever 542 and at its left hand end to the member 548 which carries stops 589, 590, 591 which are engaged by the releasable ratchets 588 and 593.