Patent GB-647805-A (GB)
Title: Improvements in or relating to starting means for rotary engines
Inventor: CLAPHAM THOMAS
IPC: F02C7/277
Filed: 1948-04-28
Abstract: 647,805. Turning-gear. POWER JETS (RESEARCH & DEVELOPMENT), Ltd. April 28, 1948, No. 11634. [Class 7(v)] [Also in Group XXVI: In a starting apparatus for use with a rotary engine of the kind having an operating cycle that requires the engine to turn at a given minimum rotational speed before useful power may be developed, comprising a rotary starter motor, such as a turbine 2, for supplying power to accelerate the rotary engine, which may be the main turbine 1, to its starting speed, an energy reservoir, such as a cartridge chamber 6, from which energy may be released and supplied to the starter motor 2 for the generation of such power and means, for example the piston controlled vent 7, for terminating the supply of energy to the motor in dependence upon the number of revolutions made by the motor subsequent to the release of energy from the reservoir, there is provided means, such as a crank 12 and opposed pistons 13, 14, for automatically modifying the number of revolutions of the motor required to open the vent 7, in accordance with the speed of the turbine 1, substantially at the instant of energy release. The turbine 1 is driven by the starter turbine 2 through a starting shaft 3, ratchet clutch 4 and reduction gearing 5 the turbine 2 being energized by gases from the cartridge in chamber 6, the latter having the opening of its vent 7 to atmosphere controlled by a piston valve 8. The shaft 3 includes a reduction gear 9 comprising a worm gear which is coupled to the crank 12 by a shaft 11 that incorporates a second ratchet clutch 10, the crank 12 having one of the pair of opposed pistons 13, 14 connected thereto, the other piston being 'joined to the valve 8 through a spring-loaded rod 16. The space between the pistons 13 and 14 is connected to a rotary liquid pump 19 that supplies lubricating oil to the turbine 1 and is driven from the'latter, the introduction of oil to the space between the opposed pistons moving the lower piston 13 only. The crank assembly is so arranged that when the starting turbine 2 has completed the requisite number of revolutions to bring the turbine 1 up to starting speed the crank assembly has moved the valve 8 to open the vent 7. In order to provide for starting when the turbine 1 has any speed intermediate rest and minimum starting speed the effective length of the connections 10 the valve 8 is made dependent upon the intermediate speed with the result that when the cartridge is fired, the pump 19, the output of which is proportionalto speed, is then no longer permitted to discharge to the space between the pistons 13 and 14, due to closure of a cock 20, so that the length of the connection will be constant and. will correspond to the intermediate speed at that instant, thereby modifying the number of revolutions required to be imparted to the turbine 1 before the valve 8 opens the vent 7. The operation of cock 20 and the cartridges could be effected from a common electrical circuit. The crank is reset after a starting operation by a motor or solenoid 22 which could be connected with the fixing circuit of the turbine 1. In a modification, the worm gear, a second ratchet clutch and crank are replaced by a piston pump on the starting shaft which moves a hydraulic piston motor connected to one of the opposed pistons, the motor being provided with a cock for resetting which is operated either . mechanically or upon operation of the firing circuit of the main turbine. The apparatus is so arranged as to preclude a second cartridge being fired whilst the resetting devices are functioning. In another modification, the opposed pistons are replaced by a quadrilateral link system which is connected by two opposite joints to the crank and valve, whilst a third joint is joined to a piston influenced by the rotary pump. The valve 8 could be of the poppet type.