GB731332A - Fluid flow control valves - Google Patents

Abstract

731,332. Valves. JOHNSON, C. Aug. 14, 1953 [April 15, 1953], No. 22446/53. Class 135. A valve suitable for controlling a double-acting piston and cylinder motor and actuated either directly by a hand lever or under the control of a pilot ball-valve which may be operated by a hand lever or by a solenoid comprises a valve member 20 with lands 58, 60, 62 flanked by resilient sealing rings 66 of round cross-section and slidable in spaced liner elements 24, 26, 28, 30. The outer sealing ring 66 of the lands 58, 62 may be omitted. The liner elements, which carry external sealing rings 42, 44, are spaced apart by cylindrical filters 34 to provide ports 36, 40 which communicate through adjustable valves 130, 128, with an exhaust manifold 16, and a port 38 connecting with a pressure fluid inlet 108. Radial ports 52, 54 in the liner elements 26, 28 connect through cylindrical filters 48 with the two ends of the motor to be controlled. The valves 128, 130, control the rate of exhausting from each end of the motor so that the speed of the latter in either direction may be determined independently. In the form shown the valve is controlled by a pilot valve comprising a ball 98 movable between opposed seats 94, 96 consisting of resilient sealing rings. An arm 158, flexibly mounted at its upper end and carrying a pin 156 to engage the ball 98, is normally urged by a spring 178 to hold the ball against the seat 94 so that a chamber 74, in which a piston 72 integral with the valve number 20 is slidable, is vented through passages 106, 104. This permits pressure fluid admitted through a filter 112 and passages 14, 114 to a piston 68 integral with the valve member to move the latter to the right. Pressure fluid from the passage 114 acting on the liner element 24 also constantly urges the liner elements to the right to ensure that the sealing ring 44 performs its function. When the solenoid 180 is energized it withdraws the arm 158 so that the ball 98 is urged to the seat 96 by pressure in the passage 14 which then has access to the chamber 74 to move the valve member to the left owing to the greater area of the piston 72 than that of the piston 68. Hardened steel inserts 77 at the ends of the valve member coact with similar, fixed inserts 79. In a modification the arm 158 is rocked by a hand lever instead of by the solenoid. The unit carrying the pilot valve may be mounted remote from the main valve. In another modification a solenoid operated pilot valve may be mounted at each end of the main valve to control the associated piston. In this case the pistons may be of the same or of differing area. In a further embodiment the valve member 20 is connected directly to a hand lever and is located in its two end positions and also in an intermediate position by a spring-pressed ball engaging grooves.