GB680055A - Selector valve - Google Patents

Abstract

680,055. Valves. MUELLER, O. July 17, 1950 [Dec. 22, 1949], No. 17788/50. Class 135. A hydraulic selector valve comprises a body 10 with an outlet 18, a high-pressure inlet 20 and a low-pressure inlet 22 and a valve member 28 for connecting either inlet to the outlet. A spring 30 urges the member to the position shown in which inlet 22 is connected to the outlet and an annular surface 68 and a shoulder 60 on the member 28 engage the end 52 of a sleeve 26 to cut off communication between inlet 20 and the outlet. To connect inlet 20 to the outlet, the low-pressure source is disconnected from inlet 22 and applied through a line 32 to move the member 28 so that annular surface 62 enters a sleeve 24 and shoulder 58 engages the end of the sleeve, thus closing communication between inlet 22 and outlet 18. To return the valve member to the former position, line 32 is opened to exhaust and the high-pressure source is cut off from inlet 20. The high-pressure remaining in the outlet acts on a differential piston valve 94, seated in the member 28, and moves the valve to the right, thus connecting the outlet through bore 118, grooves 101 in the valve and a port 120 to the line 32. The high pressure is thus gradually dissipated, permitting the spring 30 to move the member slowly to the right. In a modification, the spring 30 is replaced by a loading pressure lower than the pressure applied to the line 32, and the valve 94 is replaced by a piston valve urged to a position relieving the high-pressure by said loading pressure and moved to closed position by the pressure in the line 32.