GB288166A - Improvements in or relating to fluid pressure regulators - Google Patents

Abstract

288,166. Canada Sugar Refining Co., Ltd., (Assignees of Wettstein, F. A.). March 31, 1927, [Convention date]. Fluid relays, - Relates to fluid pressure regulators of the servomotor type controlled by variations in any physical condition or quantity, such as the speed of fluid pressure motors, temperature, water level, electrical or chemical conditions, such as the CO2 content of combustion gases, wherein means are provided whereby the static pressure of the fluid operating or controlling the servomotor is utilized directly to oppose the force immediately determining said static pressure and to balance the said force. By this means dash-pots in the regulating mechanism are avoided, and the regulating mechanism is connected to the mechanism operating the control member by one or more fluid pressure conduits only without the aid of mechanical interconnection, so that the two mechanisms may be disposed at a distance the one from the other. Fig. 1 shows a pressure regulator controlled by a speed governor and embodying a direct resilient fluid pressure return motion ; the speed governor, however, merely typifies means responsive to any regulating impulse. With a decrease of speed, the governor spring 8 moves upwards, the combined piston pilot valve 10, 11 and return motion piston 17 allowing regulating pressure fluid entering at 15, 16 to pass through conduit 19 to the servomotor piston 24, and also through the pipe 23 to the upper side of the return motion piston 17; simultaneously, fluid from the opposite sides of the pistons 17 and 24 escapes through conduits 20 and 22 to the discharge 12. The consequent pressure differential in the servomotor 21 moves the piston 24 upwards to open the valve more to give an increased power supply to the prime-mover, and also forces down the returnmotion piston 17 until the pilot valve 10, 11 reaches its normal position; in this position the process of regulation is completed and the pistons 17 and 24 are stationary. In the absence of a loading spring 25, the speed at the close of the regulation is the same as at the beginning and variations are only temporary. Permanent variations of speed according to load can be provided for by a loading spring 25 of suitable stiffness. An arrangement is shown in which increased power and accuracy of control are obtained by providing two relays in series, one relay valve being disposed on the servomotor cylinder, and the return motion piston 17 being separated from the governor rod 9 and operating thereon through a spring.