GB636315A - Improvements relating to pressure-responsive valves - Google Patents

Abstract

636,315. Fluid-actuated valves. PRECISION DEVELOPMENTS CO., Ltd., BOX, F. J., and OLAH, G. July 24, 1945, No. 18893. [Class 135] In a piston slide valve displaceable within a ported cylindrical seat member against the action of resilient means by a fluid-pressure operated coaxial actuating unit, the actuating unit comprises a cylinder and a co-operating ram of smaller diameter than that of the valve seat member, and a passage is formed in the piston valve establishing communication between the cylinder and a pressure chamber, such as the valve inlet chamber in the case of a relief valve, or the valve outlet chamber in the case of a reducing valve. A relief valve comprises a housing 23, Fig. 1, for a cylindrical seat member 2 having radial ports 8 commimicating with an inlet chamber 9, radial ports 5, connected by passages 34 with an outlet chamber 6, and controlling edges 12 leading to the ports 8, and the ports 5. Within the seat member 2 is a piston valve 1 urged towards closure by springs 15 symmetrically arranged between ball-supported plates 16, 18 disposed between the valve and an adjusting screw 20. The valve 1 is formed with grooves 10, 11, and controlling edges 13 leading thereto which coact with the controlling edges 12, and with a bore 24 for the ram 25 of the actuating unit, said ram being freely supported by the casing cover 26. A space 27 above the ram 25 cornmunicates through a duct 30 and a recess 29 in the ram and radial passages 28 in the valve with the inlet chamber 9, whilst ducts 43, 44 connect the upper and lower surfaces respectively of the valve with the outlet chamber 6. In operation, on the pressure in the inlet chamber 9 exceeding a value predetermined by the springs 15, the valve 1 is forced upwards to separate the controlling edges 12, 13 and hence permit the flow of pressure fluid from the inlet chamber 9 through the ports 8 and symmetrically through the ports 5 to the outlet chamber 6. In a modification, the ram of the actuating unit is formed by an extension 35, Fig. 3, of the valve 1 which coacts with a cylinder 37 freely supported on the cover 26 and open to communication with the inlet chamber through passages 28, 36. When used as a reducing valve, the springs are arranged to bias the valve towards its open position and the space 27 communicates with the outlet chamber 6.