GB581684A - Improvements in power plant - Google Patents

Abstract

581,684. Motor power plant. BAILEY, R. W., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. July 9, 1941, No. 8670. [Classes 110 (ii) and 110 (iii)] [Also in Group XXIX] A plant comprising both steam and I.C. reciprocating engines is reversed by the operation of the steam-engine gear which cuts off the fuel supply for the I.C. engines. The rotation of the I.C. engine is then reversed by the power of the steam engines. After reversal of the rotation, and reversal of the mechanism of the I.C. engines (an axial displacement of a shaft having two sets of cams), the fuel supply to the I.C. engines is opened again and thereafter is regulated from the steam-engine gear A time-delay device determines the reopening of the fuel supply and during the reversal of rotation the power of the steam-engine is increased by, e.g., putting the h.p. and i.h.p. cylinders in parallel. The arrangement is applicable to plant in which I.C. engines are combined with steam turbines, or electric motors, and is specially applicable to plant in which hydraulic couplings or other couplings having slip are employed. A rod 22, Fig. 1, coupled to the steam-engine link gear carries with it a block 21 held between springs 24. The block is connected to a lever 18a and to a cam 25 controlling the fuel supply to the I.C. engines. Normally, the cam 25 follows the movement of the link gear since the lever 18a is free to move in a slot in a bar 18 which is long enough to accommodate the whole of the control movement for one direction. When the link gear is reversed the cam 25 follows up to the mid-position and thereafter the lever 18a is held and one of the springs 24 yields. The bar 18 is coupled to a piston 17 in a cylinder supplied with oil from a pump 11 driven by the I.C. engine. When these are reversed, the oil moves the piston 17 to the other end of its cylinder and the slot in the bar 18 then allows the cam 25 to follow the movements of the steam-engine link-gear in reverse. The time taken in moving the piston may be determined by means of a bye-pass and the flow in the latter may be controlled in accordance with the speed of the engines. The pump 11 has valves 14 which secure a uniflow delivery at 13 for lubrication and a valve 19 which provides for a minimum of oil pressure. The valves for altering the steam distribution are operated from a cam 28, Fig. 4, moving with the link-gear and are returned to normal by a rod 37 moving with the cam 25, Fig. 1. Movement of the cam 28 in either direction through its midposition cants a three-armed lever 33, on a valve-operating shaft 30, depresses a frame 34 and turns a shaft 44. In this movement a latch 40 is lowered and, when the I.C. engine reversal is complete, the rod 37, through the latch 40 and shaft 44, returns the frame 34 &c. to normal. The steam distribution valves are operated by pressure cylinders to which steam is admitted by a valve, Fig. 6, actuated by the shaft 30, Fig. 4. The valves are held in normal position by steam pressure, the cylinders being connected to pipe 60 and an exhaust to pipe 61. The under side of a piston 75 of smaller area than the valve 73 is connected to the exhaust by passages in the valve stem. The valve 73 is thus held in the closed position, but the bias is reversed when the valve is opened. In a modification the steam distribution valves are held closed by spring pressure and are opened by steam pressure. In this case, the pipe 60 is connected to the steam supply and the pipe 61 to the pressure cylinders. The cylinders are normally connected to exhaust through the hollow valve stem ports 71 and an outlet 72 shown in the dotted-line addition. When the valve 73 is opened to admit steam to the pressure cylinders, a fixed piston 70 closes the ports 71 in the exhaust line. Specifications 581,680 and 581,681 are referred to.