GB930657A - Improvements in or relating to air pressure reducing devices operating with a double valve system - Google Patents

Abstract

930,657. Valves. REGIE NATIONALE DES USINES RENAULT. Oct. 19, 1959 [Nov. 5, 1958], No. 35297/59. Class 135. An air pressure reducing device comprises a housing 1 having inlet and outlet ports 31, 32, a main valve 7 and secondary valve 22, the main valve member engaging, when closed, a stationary seat 6, the secondary valve being spring-loaded in the direction of closure and tending to close the main valve, and a piston 14 having a stem 17 which passes through the main valve, the stem being arranged to engage the secondary valve to move it against the spring loading and being provided with an abutment for opening the main valve, the piston being subject to air pressure downstream of the valves and being loaded by a spring 33 acting against the effect of this latter air pressure. The main valve 7 is guided in a bore 23 formed in an upper body portion 1 of the device and adapted to engage the seat 6 provided in a member 4, 5 located in a lower body portion 2. In operation, before compressed air is fed into the inlet 31, both valves 7, 22 are lifted from their seats 6, 30 by the spring 33 acting against the piston 14, the spring being adjustable through a hand-wheel-and-nut arrangement 34, 40. When the air is admitted into the inlet it passes through both valves into an annular chamber 43 leading to the outlet 32 and when the pressure in the chamber reaches a certain predetermined amount the air acts on the piston against the action of the spring 39 and thereby allows the valves 7, 22 to gradually close until the required reduction in pressure is obtained in the outlet 32. All the parts of the reducing valve, except the springs, may be of plastics material.