GB698731A - Improvements in or relating to gas valves operated by differential pressure - Google Patents

Abstract

698,731. Gas valves. REGWELL, Ltd., and SALINGER, G. T. April 28,1950 [April 29, 1949], No. 11383/49. Class 135 In a relay or safety cut-off gas valve operable by the difference in pressure acting on opposite sides of a diaphragm, the passage connecting the opposite sides of the diaphragm co-operates with a needle having a sharp-edged bottom and supported in the casing to permit of slight transverse movement in all directions, so as to provide a restricted path for the flow of gas and on the movement of the diaphragm in one direction permit the needle to clean the passage by the removal of any deposit into a wider channel connected with the main gas flow. As shown, the relay valve comprises a casing 1, Fig. 1, between the two parts of which is a diaphragm 5 secured by a member 10 to a valve disc 9 engageable with a seat 8 to control gas flow from an inlet 3 to an outlet 4. The member 10 has an axial passage 13 opening out into larger diameter 14 and transverse passages 15 and co-operates with a needle 16 supported with clearance in a hole 18 in the casing by a disc 17. An outlet 22 above the diaphragm is controlled by a remotely disposed valve operable by a thermostat, or by hand &c. On the remotely disposed valve closing, pressure above the diaphragm builds up to balance the pressure acting on its underside and the valve 9 closes under its own weight. As shown in Fig. 2, the valve is modified for use as a safety-cut-off valve which closes, e.g., when a pilot jet is extinguished. In this embodiment 4 is the inlet and 3 the outlet and a member 41 connecting the diaphragm 5 with the valve disc 9 provides communication between the valve inlet and the upper side of the diaphragm. In this case when the valve closes on a build-up of pressure above the diaphragm the valve can only be re-opened by leaving the outlet 22 open and temporarily connecting the inlet and outlet sides of the valve to a press button valve to remove the disc 9 from its seat. The valve is guided to its seat by a guide peg having a double ball-shaped head slidable in a hollow peg.