Patent GB-736394-A (GB)
Title: Improvements relating to gas turbine ignition apparatus
IPC: F01D17/06
Filed: 1951-09-13
Abstract: 736,394. Gas turbine plant. FAIREY AVIATION CO., Ltd., CHAPLIN, H. E., and EBEL, F. L. Nov. 25, 1952 [Sept. 13, 1951], No. 21567/51. Class 110 (3). [Also in Group XXVII] Gas turbine ignition apparatus includes means responsive to the speed of the turbine for controlling the igniter so as to render it operative only when the turbine attains a predetermined speed, means being provided to switch off the igniter a predetermined time after the turbine attains that speed or a greater predetermined speed, provided that the turbine has started. In Fig. 5, the shaft 55 is driven at a speed corresponding to turbine speed and carries a sleeve 59 slidable in response to the centrifugal weights 52. The shaft 61 also carries a sleeve 62 slidable in response to the centrifugal weights 60. When the starter is operated, the shaft 61 is driven by engagement of the clutch members 65, 66 on the sleeves 59, 62. As the sleeve 62 rises, the pivoted lever 68 which is engaged by the flange 67 on the sleeve 62, engages the switch arm 69 and at a certain speed the contacts 70, 71 close and close the igniter circuit. With further increase in speed the clutch members 65, 66 separate so that the driven member is then free and the sleeve 62 begins to move downwardly, but as soon as the turbine begins to accelerate the driving member attains such a speed that the clutch member 65 is completely withdrawn so that it will be clear of the driven clutch member 66 even when the driven member is at rest. In the embodiment of Figs. 1, 3 and 4 the driving shaft 11 and driven shaft 15 may be connected through a clutch member 13 operated by a solenoid 14. The driven shaft 15 carries a disc 17 on which two centrifugal arms 18, 19 are pivotally . mounted at 20, 21. The pivot 20 carries a switch-operating member 27 having a rigid detent 38 and two retractable latches 31, 32. When the push-button 43, Fig. 4, is pressed, assuming the throttle switch 42 closed, current passes through the solenoid 14, thereby causing the clutch 13 to engage. Current will also pass through the holding relay 44, thereby closing the contacts 45, but current will not flow through the holding circuit as the switch 28 is still open. An indicator light 50 is in parallel with the coil 44. The circuit through the relay 48 will be closed simultaneously, thereby closing the circuit of the starter motor 49. As the centrifugal weights begin to move outwardly, the latch 32 engages with the arm 36 which engages the contact 30, completing the holding circuit so that current continues to be supplied to the changeover switch 39, 40, when the push-button is released. When the centrifugal weights reach their outermost position E, the change-over switch arm is operated by the detent 38 causing the solenoid 14 to be switched off and the igniter 51 to be switched on. As the weights move in, the holding switch arm 28 is opened by means of the detent 31 engaging the arm 35, thereby causing the igniter to be switched off, and as the weights reach their innermost position C the change-over switch is returned to the solenoid position by engagement of the detent 38 with the arm 37.