Patent GB-914664-A (GB)
Title: Gas turbine engine
Inventor: WILKINSON WILFRED HENRY
IPC: F01D25/20
Filed: 1961-09-27
Abstract: 914,664. Lubricating. ROLLS-ROYCE Ltd. Sept. 27, 1961, No. 34767/61. Class 12 (3). [Also in Group XXVI] A gas-turbine engine comprises drive transmission means which are drivingly connected to the engine compressor and which are adapted to be driven by a starter motor, means being provided for effecting lubrication of one or more parts of the drive transmission means immediately the latter are driven by the starter motor. The compressor and turbine shaft of a gas-turbine engine is indicated at 10 in Fig. 1 and the engine may be started by a starter motor 23 driving a quill-shaft 22 through a clutch device 24, the shaft 22 being connected to the shaft 10 through bevel gearing 15, 14. An oil reservoir of cylindrical form is provided at 30, the reservoir containing a piston 31 having a pressure surface 33 at its left-hand side. The piston is urged towards the left by a spring 32. The reservoir comprises a reduced diameter portion 40, a conduit 42 through which oil is discharged on to the bevel gearing 14, 15, and an oil supply duct 43 which is connected through a non-return valve 45 to an engine-driven lubricating oil pump. The left-hand end of the reservoir 30 is connected to a pressure fluid duct 34. When the engine is not running, the piston 31 is at the left-hand end of the cylinder and the cylinder is filled with oil, the left-hand end of the cylinder being vented through ducts 34 and 37, the valves 35 and 27 being in the closed positions shown. To start the engine, the interconnected valves 27, 35 are opened to allow fluid under pressure to pass from a source thereof to actuate the starter motor 23. Simultaneously, fluid under pressure passes through duct 34 into the left end of the cylinder 30, whereupon the piston 31 is moved to the right against the loading of the spring 32 and oil contained in the cylinder is discharged through the duct 42 on to the gearing 14, 15, the non- return valve 45 preventing oil passing through the duct 43 to the engine-driven lubricating oil pump. When the pressure developed by the pump has risen sufficiently, the valve 45 will be opened and oil will pass from the pump, through the duct 43, the reduced diameter end portion 40 of the cylinder 30 and through the duct 42 on to the gearing. When the starter motor is disengaged, the valves 27, 35 are closed and the left-hand end of the cylinder is vented to atmosphere through the duct 34, 37, and the piston 31 moves to the left-hand end of the cylinder under the influence of spring 32. The cylinder will be re-filled with oil and oil will continue to discharge through the duct 42 on to the gearing. When the engine is stopped, the cylinder will remain filled with oil since the ball valve 45 will be closed automatically. The oil reservoir is thus charged ready for the next starting operation. In a second embodiment, Fig. 2, the piston 31a carries a valve stem 52 having a valve 53 which engages a seat 54 when the piston is at its left-hand limit of movement. As before, the valves 27a, 35a are opened at starting, and the piston 31a moves to the right, opening the valve 53, 54 and discharging oil through the duct 42a on to the gearing. As the engine-driven pump is brought into operation, oil will be delivered by the pump through the ducts 44a, 50 on to the gearing. As the pressure generated by the pump increases, the non- return valve 51 will be opened and oil will then pass also to the gearing by way of the duct 43a, the reduced diameter portion 40a of the cylinder 30a, and the duct 42a. When the starter motor is disengaged however, the piston 31a will move to left-hand end of the cylinder and the valve 53 will close leaving the cylinder filled with oil ready for the next start. Oil will continue to flow to the gearing by way of the duct 50.