GB549279A - Improvements in self-closing valves for controlling the flow of fluids - Google Patents

Abstract

549,279. Self-closing valves. HOPKINSONS, Ltd., and DALE, W. B. Dec. 6, 1941, No. 15767. [Class 135] A self-closing valve automatically closing on failure or cessation of supply and re-opened by a manual operation particularly adapted for controlling the supply of compressed air to mine machinery comprises a main valve member a opening in the direction of flow and actuated by a leaky piston f controlled by a spring loaded auxiliary valve h actuated by a diaphragm j. To open the main valve a quadrant o is actuated by a detachable handle p to hold the valve h closed so that pressure leaking past the piston balances the pressures on the piston so allowing the inlet pressure acting on the valve member to move it to the open position. Outlet pressure passing through the passage m to the chamber k acts on the diaphragm to hold the valve h closed. Should the outlet pressure fall abnormally the spring j<SP>1</SP> opens the valve h and connects the chamber above the piston to atmosphere through a passage i so allowing pressure below the piston to close the main valve. To test the device the quadrant is operated to close a valve n in the passage m and open a slide valve r to connect the chamber k to atmosphere. The handle p has a socket adapted to engage a squared end on the spindle of the valve q when a projection on the socket is passed through a recess in a guard member.