Patent GB-770991-A (GB)
Title: Improvements relating to starter motors for internal combustion engines
IPC: F02C7/277
Filed: 1952-05-16
Abstract: 770,991. Engine turning gear. BRITISH THOMSON-HOUSTON CO., Ltd. May 16, 1952 [May 17, 1951], No. 12440/52. Class 7 (5). [Also in Groups XXVI and XXVIII] A turbine type starter motor comprising a turbine fed with working fluid by a combustion chamber to which fuel and a combustion supporting fluid under pressure are supplied has an electrically-operated control valve, regulating the supply of combustion supporting fluid, which is biased to the closed position and opened by the completion of an electric circuit and means responsive to the speed of the turbine to interrupt the circuit and close the valve when the turbine reaches a predetermined speed. The gas turbine type starter shown comprises a combustion chamber 3 feeding a turbine 2 connected to the engine to be started through a clutch 4 and shaft 6. The clutch 4 may be of the unidirectional or pressure operated type. Air or other combustion supporting fluid stored in a bottle 7 is supplied to the combustion chamber 3 through a solenoid operated control valve 9 and regulating valve 11. The valve 9 is biased to its closed position and opened by energization of the solenoid. The valve 11 may be of the type which maintains a constant pressure on its downstream side or of the type which varies the pressure of the air supplied to the combustion chamber in response to a condition of the turbine 2 such as speed, temperature or combinations thereof. A pressure relief valve 12 is also provided. To start the turbine, the switch 43 is closed and is held closed by the solenoid 47. This energizes the solenoid 10 and the control valve 9 is opened. Air then flows from the bottle to the combustion chamber 3 through the conduit 8a and to the restrictor valve 21 through a conduit 20. The air pressure on the piston 24 forces it downwards against the action of the spring 25 and air then passes through the passageways 32, 33, 34 and port 36 to the chamber 17 of the accumulator 13. This causes fuel contained in the chamber 18 to be forced through the check valve 38 into the combustion chamber. If a pressure operated clutch is employed, air also passes through a conduit 8b to the clutch and the turbine is connected to the engine to be started. If a unidirectional clutch is employed, the conduit 8b may be dispensed with. If the load on the turbine 2 is removed due to the failure of the clutch or early starting of the engine, the turbine would tend to overspeed. To prevent this, a switch 39 in the circuit of the solenoid 10 is opened when a predetermined speed is reached. The-valve 9 is then returned by its biasing means to the closed position. A manually operated switch 42 may also be used to shut down the plant. Under certain conditions there may be a backflow along the conduits 37, 20. This backflow will cause valve 21 to vent the chamber 17 to atmosphere. When valve 9 is closed, the valve 21 vents chamber 17 to atmosphere and fuel is fed by gravity from the tank 50 through valve 52 into the chamber 18. The valve 38 is biased to the closed position so that fuel does not enter the combustion chamber 3 when the valve 9 is closed. Specification 662,601 [Group XXIV] is referred to.