Patent GB-595548-A (GB)
Title: Improved means for controlling the cyclic operation of components of a power plant
IPC: F02C5/06
Filed: 1942-11-04
Abstract: 595,548. Servomotors. ENGLISH ELECTRIC CO., Ltd., and WELSH, R. J. Nov. 4, 1942, No. 15552. [Class 135] [Also in Groups XXVI and XXVII] A power plant comprising a number of free piston internal combustion engines, L1, M1, N1, P1, whichproduce combustion gas to drive a turbine, is governed by the turbine speed to control the supply of fluid to servomotors L100 ... P100, so that as load on the turbine increases, the units .L1 ... P1 are started up and reach maximum load in turn. On decrease in load, the units are cut out in the order L1 ... P1 so that the first unit to take on load, is the first to be rested. Each servomotor (i) operates an output regulator controlling the fuel supply, (ii) transmits a starting signal to the next unit in cyclic order when its own unit reaches, or approaches, maximum output, (iii) ensures on reduction of the desired turbine output below a certain figure, that a unit next in cyclic order either to one at rest, or to the last one to start, is stopped. Each compressor L2, M2, &c., driven by internal-combustion engines L1, M1, &c., has compressed air starting means. A unit is started-up by fluid pressure passing through a pipe 75 Fig. 3) to a starting relay 49, which controls a servomotor operating a master starting valve 55 to supply compressed air through a pipe 62, and a further valve L63, to buffer cylinders at each end of the engine. Valve L63 shuts off the air supply when the engine starts. The engine can be stopped by cutting off the fuel supply through a pump 10, and devices such as L32, L35, causes the opposed piston units to be separated and the whole unit set in readiness for automatic re - starting. Specification 595,547, [Group XXVII], gives details of the starting up of each engine, details of the valve L37 and re-setting of the units'pistons for restarting. When the unit L1 is at rest, the valve 37 allows fluid pressure from supply line L42, to pass to pipe L33, but cuts off this supply and connects L33 to exhaust, when L1 is in action. The operation of valve L37 is described in Specification 595,547, [Group XXVII]. Movement of the piston 109 in servomotor L100 controls the movement of a rack 10a of a fuel injection pump 10 and so controls the engine output. A counter pressure device L107 also acts on the fuel rack lever, fluid passing from pipe 33. Fluid supplied to the servo-motor from the pipe L106 is regulated by a throw over valve L101. Atmospheric air enters unit L by an inlet L14, and the engine cylinder L1 exhaust through L16 to a pipe 102 leading to the turbine inlet. The turbine governor actuates a slide valve to connect a fluid pressure supply pipe to the pipe 106, on decrease in turbine speed, and to exhaust on an increase in speed above a predetermined value. Backward movement of piston 109 is limited by a releasable stop 110, associated with a stop piston 111 which can be held in its right hand position by fluid pressure through pipe L113 acting on a further piston 112. The piston 118 in valve L101, has pressure applied to it for a brief period immediately after its associated engine is stopped, tending to move it to the left to a closed position and shut off the control pipe 106 from pipe 121. The piston 118 may be set manually by means of the projecting rods 122. When the piston has moved well over to the right of its cylinder, and the engine is running at approximately maximum output, a part 108d, is uncovered, and control pipe 106 is connected by a pipe 75 to the starting relay of the next unit. Fluid trapped behind piston 109 may pass through a pipe 125. and non-return valve 126 to the supply pipe 106, when the piston moves to the left, Fluid from the relay cylinder 49 may pass through a pipe 123, non-return valve 124, to the pipe 106. Each valve 126 may act as a pressure-reducing valve so that for the next unit, and so on, the pressure will be less in each successive servomotor 100.