GB472787A - Improvements in elastic-fluid power plants - Google Patents

Abstract

472,787. Fluid-pressure servomotorcontrol systems. BAILEY METER CO. Nov. 27, 1936, No. 32517. Convention date, Dec. 18, 1935. [Class 135] [Also in Group XXVI] An elastic-fluid, power plant comprises an elastic-fluid generator supplying. fluid to a principal prime mover, and auxiliary apparatus whose power output is made automatically dependent on the generator outlet pressure and pressure in the principal prime mover jointly. A drumless forced-flow vapour generator with a single sinuous tube supplies fluid to a main turbine 12 from which steam is drawn wholly or in part to operate an auxiliary turbine 287 driving a water pump 289 to feed the generator, a blower 288 to supply air to the furnace, and a pump 290 to supply oil to the burner 4. The fluid from the vapourizing section passes to a trap 232 and then through a superheater 242. Liquid from the separator passes through a valve-controlled pipe 1 with a restricted byepass 2 to waste or a hotwell. The furnace ignition is started by a gas-burner torch. The products of combustion may heat the separator. The oil supply in addition to control by the pump speed is also controlled by a valve 13, the rate of flow being measured by a meter 14. The air supply is controlled by the speed of the blower and by a damper 15. A meter 16 measures the rate of flow. A Bourdon-tube device 19 indicates the vapour-outlet pressure. A similar device connected to the first stage shell indicates the load on the main turbine 12. The liquid level in the separator is indicated by a pointer 30. The meters 14, 16 co-operate to control the oil supply valve 13 to maintain the fuel air relationship. Different variations of air and oil flow adjusts the valve 13. The supply of liquid to the generator and of the oil and air for combustion are primarily controlled by controlling the speed of the auxiliary turbine which is controlled by the superheater pressure, by the main-turbine shell pressure, and by the auxiliary turbine speed. The auxiliary turbine is supplied with high-pressure vapour, main turbine exhaust vapour, and bleed steam respectively through conduits 500, 502, 504. The auxiliary turbine is normally driven by exhaust and bleed steam. The valve chest of the auxiliary turbine is divided into three parts which supply steam from the pipes 500, 502, 504 under the control of valves actuated by a staggered cam on a shaft. The exhaust steam is supplied first and the high-pressure steam last. The auxiliary turbine operates at a speed roughly in step with the main turbine. An oil pump 506 driven by the turbine 287 supplies oil to a bellows under adjustable spring-pressure which moves the end of a lever 509. The other end is moved by a piston in a cylinder 511 which also moves the valves controlling the supplies from pipes 504,500, 502. A pilot valve is arranged in casing 43. Fluid under pressure is supplied to the centre of the casing 43 and accordingly as the rod 42 is moved up or down, fluid is passed to the upper or lower right-hand connection. If the pressure in the pipe 507 falls as a consequence of decrease of auxiliary turbine speed, the piston in cylinder 511 rises and opens admission valves. The superheater pressure actuates a pilot valve to supply pressure air to the pipe 513. The turbine casing pressure similarly actuates a valve controlling the air supply 46. The pressures differentially effects the loading of a diaphragm 515 which adjusts the governor