GB1535714A - Means for controlling the supply of combustible gas and incorporating gas valve means - Google Patents

Abstract

1535714 Valves CONCENTRIC CONTROLS Ltd 18 Dec 1975 [16 Oct 1974] 44745/74 Heading F2V Means for controlling the supply of combustible gas comprises a flame-failure device having a gas valve and a hollow probe 29 communicating through a duct with the interior of an expansion chamber 27, 28, the probe, duct and chamber, containing a liquid which expands on being heated, the gas valve comprising a valve member 17 movable between a closed position and at least one open position, and a by-pass 25 which normally allows gas to flow at a relatively slow rate when the valve member is closed, and closure means 37, which is inoperative when the chamber 27, 28, of the flame-failure device is expanded, but which becomes operative as the expansion chamber contracts to move valve member 17 to its closed position, if not already in that position, and to close the by-pass 25. The gas valve comprises a manually rotatable plug with a cam track which moves a rod 11 axially to urge a beam 16 against an abutment 20 carried by an expansion chamber 21, which is connected to an oil-filled temperature-actuated probe, by an oil-filled tube 22. Valve closure 17 is urged to close a seat 23 against the action of a blade spring 19, by a spring 18, and by the action of chamber 21. A corrugated diaphragm 27 is actuated by the liquid-mercury-filled probe 29 when the latter is heated by a pilot burner, to cause a lever 33 to pivot and override a spring 38, so that closure 37 moves upwardly to open by-pass 25 and a reduced amount of gas passes to the main burner through inlet 24. If the pilot burner is extinguished, spring 38 operates to close valve member 17 and also by-pass 25. The gap supply to the pilot burner may be controlled by the plug which moves rod 11.