GB329653A - An improved safety valve for air pressure systems - Google Patents

Abstract

329,653. Keywood, C. F. Feb. 21, 1929. Valves controlled by pilot or relay valves.- A safety-valve particularly adapted for use in connection with air compressors has a main ball valve 26 opened by fluid pressure acting on a spring loaded diaphragm 31 under the control of a spring loaded auxiliary valve 43 arranged to open in the direction of the actuating chamber. The main actuating spindle 39 is secured to a piston 37 bearing against the diaphragm which is clamped against a shoulder in the casing by a screwed ring 32. The auxiliary valve, which is loaded by a spring 44 adjusted by a plug 45 screwed into a detachable cap 45<1>, is actuated either by the pressure in the receiver 1 transmitted through passages 18<1> 18, 19 and 40, or by line pressure transmitted through the passage shown in broken lines. A spring loaded check valve 20 is interposed in the pipe line to prevent return flow. A screwed nipple 22f adapted to receive a pressure gauge is fitted with a valve 22c normally held open by a spring but adapted to close with rush of fluid on removal of the gauge. To ensure prompt closing of the main valve a local venting valve 49 closed by a spring 50 slightly stronger than the spring 38 is mounted in a cap 35 closing the actuating chamber. This valve may be positively opened by a rod 48 having a foot resting on the actuating diaphagm when the diaphragm is lifted by admitting pressure beneath it. The pressure may be supplied when an outlet valve from the receiver is operated and slowly leaks away through a leakage passage provided at 39<1>. In a modification the valve 49 is' adapted to be raised by a hand lever. The reservoir is fitted with a spring loaded ball valve 7 adapted to be moved to the open position by a ported member 14 secured to the screwed nipple 11 of the main valve casing, when the casing is screwed into position. Specification 311,548 is referred to.