GB586727A - Improvements in or relating to pressure regulating valves - Google Patents

Abstract

586,727. Fluid-pressure servomotorcontrol systems. BENDIX AVIATION CORPORATION. May 23, 1944, No. 9953. Convention date, Sept. 3, 1943. Addition to 568,921. [Class 135] The regulating valve for fluid pressure systems described in the parent Specification is modified by providing in the body of the valve a bore which intersects the inlet, accumulator and reservoir connections and by further providing a second bore in the valve body which intersects a separate exhaust or drain opening for exhausting accumulator pressure from behind the byepass valve past one of two interconnected ball valves. As shown, the valve comprises a body 10 with connections 32, 34, 36 to a reservoir 12, a pump 20 and an accumulator 24 respectively. These connections all communicate with a chamber 40 adapted to be closed at one end by a non-return valve 48 and at the other by a relief valve 58. The non- return valve comprises a spring-pressed ball in a ported cylindrical guide and seat member 44 held in place by a locking ring 53. The relief valve:58 co-operates with a seat 64 and slides in a bore 59. This valve has a recess to accommodate a sealing ring 62 and is loaded by a spring 68 abutting a closure plug 70 and arranged in a chamber 72. The pressures at which the valve 58 opens and closes .is determined by the pressure in. the chamber 72 which is connected by passages 122, 120, 118 with a bore 96 in which a member 90 with annular grooves for sealing rings 94 is retained by a screwed plug 98. A plunger 100 with reduced end portions 102 slides in a bore 104 in the member 90. Coaxial bores 106, 108, the former smaller and the latter larger than the bore 104 are provided in the member 90. The outer ends of these bores provide seats for ball valves 82; 111 respectively. The former is urged towards its seat by a spring 80 arranged in a bore 78 and adjustable by a screw 74 concealed by a screw plug 75. The valve 111 is urged to its seat by a spring 114, but cannot close due to the plunger 100 until the valve 82 is open. The bore 78 is connected to the reservoir by an exhaust or drain opening 123 and a pipe 18. The passage 118 is connected to passages 110, 112 which connect the bore 106, 108 on either side of the plunger 100. The chamber in which the valve 111 operates is connected by a passage 116 with the outlet side of the check valve 48 and hence with the accumulator. When the pressure in the accumulator has reached its predetermined upper limit determined by the adjustment of the spring 80, the valve 82 is opened and the chamber 72 connected to atmospheric or reservoir pressure by way of passages 122, 120, 118, 110, the bore 78 and the pipe 18 and the relief valve 58 opens. The valve 111 seats to seal off the accumulator pressure from the chamber 72. When the accumulator pressure falls to a predetermined lower limit due to supply of the fluid to hydraulically-actuated devices by a pipe 28, the spring 80 can open the valve 111 and close the valve 82 so that pressure once more builds up in the chamber 72 and the relief valve 58 closes. Adjustment of the spring 80 changes the upper and lower limits of pressure simultaneously. The range of these pressure limits is determined by the ratio of the areas of the seats of the valves 82, 111 and for the purpose of changing this range, the member 90 may be interchangeable with similar members having different sized bores.