GB714023A - Improvements relating to hydraulic stabilizing arrangements applicable to steam turbines - Google Patents

Abstract

714,023. Fluid-pressure servomotor-control systems. GENERAL ELECTRIC CO. Oct. 16, 1952 [Oct. 17, 1951], No. 26004/52. Class 135 A hydraulic stabilizing device for a hydraulic servo-operated pressure regulator controlling the steam supply from a boiler 2 to the shaft glands 3a of a steam turbine 3, comprises a first variable volume chamber 17 constituted by bellows 16, 18 housed in a casing 11 and responsive to the pressure at the glands through a pipe 13, and a second variable volume chamber 26 housed in a reservoir 28 and connected by pipes 1a, 20 with the first chamber. Springs 23, 24 tend to maintain the chamber 26 at a predetermined volume, and a throttle valve 21a in a pipe 21 connecting the reservoir with both the chambers determines the speed at which the bellows 16, 18 react to any pressure changes in the pipe 13. With the throttle 21a fully open and, e.g. an increase in pressure at the glands the volume of the chamber 17 is immediately reduced to adjust through the spring-loaded rod 4 a pilot valve 6 supplying hydraulic fluid to a servomotor 7 to open a valve 9 to admit steam from the boiler to a condenser 3b and so permit the partial closure of a valve 8 admitting steam from the boiler to the glands to reduce the pressure at the glands. In this case, the chambers 17, 26 have little effect on the movement of the rod 4, the liquid from the chamber 17 being quickly transferred to the reservoir 28. On partial closure of the throttle 21a, the rate of transfer of liquid from the chamber 17 to the reservoir 28 is reduced and transfer of liquid from the chamber 17 to the chamber 26 is resisted by the spring 23. Specification 498,351 is referred to.