GB701682A - Improvements in or relating to automatic regulating apparatus, e.g., speed governors - Google Patents

Abstract

701,682. Fluid-pressure servomotor-control systems. STEVENS, A. H. (Woodward Governor Co.). Feb. 23, 1949, No. 4934/49. Class 135 A regulating apparatus, e.g. a prime mover speed governor, comprises a piston valve 29 slidable in a sleeve 20 driven by the prime mover and actuated by flyweights 9 subject to speed variations to connect a passage 37 to a liquid supply pump 31 through a passage 32 or to exhaust through a passage 34. Passage 37 leads to one side of a piston 38 the other side of which is connected to a servo cylinder 13, the piston being centered by opposing springs 40, 41. Variations of speed thus cause variations of the pressure in the passage 37 which move the piston 38 and vary the pressure acting on a servo-piston 12 controlling, e.g. the prime mover throttle. A differential pressure is thus produced across the piston 38 and is applied through passages 47, 48 to opposite sides of a piston 42 carried by the valve, the resultant force tending to move the valve back to its neutral position causing the apparatus to have a drooping characteristic. This droop is only temporary since the passages 47, 48 are interconnected by a passage 50 having an adjustable orifice which permits the pressures on opposite sides of piston 38 to equalize after an interval. The loading of the speeder spring 22 is variable through a rack and quadrant which is manually operated. Seals 52 ... 54 are provided for the piston 12, the rod 11, and the valve stem respectively, each comprising a groove 55 fed with pressure fluid from the passage 37. In another arrangement, the piston 12 is double-acting, the piston 38 being arranged in one of the passages between the valve and servo cylinder.