GB811710A - Gas flow control valve assembly - Google Patents

Abstract

811,710. Controlling gas burners. A-P CONTROLS CORPORATION. June 7, 1955, No. 16336/55. Class 75(1) [Also in Groups XIII and XXIX] A gas flow control valve comprises a body having an inlet 11 containing a pilot burner flame safety valve 12, a main burner outlet 44 and a pilot burner outlet 33, a manual valve 24 including a conduit 25 leaving the body downstream of valve 24 and re-entering the body at a chamber 43 connected to outlet 44 and a valve stem 53 carrying two valves 45, 46 controlling two seats 47, 48 in series in the conduit, so that valve 45 seats first and further stem closing movement takes up lost rotion at 50 to seat valve 46. On turning cock 24 to pilot position and depressing the knob 34 a rod 38 turns a lever 40 to open a valve 12 so that gas from the inlet passes via valve 12 and passages 26, 27, 28, 30 to the pilot burner. With the pilot burner alight a thermal couple 16 energizes a magnet which holds an armature of the valve 12 and keeps this valve open. Gas passes a pressure regulating valve 18 through the open valve 24 to the conduit 25 and past the valves 45, 46 to the main burner outlet. When e.g. room temperature increases, the bulb 57 and bellows 60 rotate a lever 62 in an anti-clockwise direction about a pivot 63 against the force of an adjustable temperature setting spring 65 and against a spring 72 through a roller 75 co-acting with a cam 69 on the lever 62. Movement of lever 62 is communicated via over-ride spring 77 and adjustable stop 78 to lever 76 and stem 53 to move valve 45 from an open, high fire position towards a closed position in which gas is supplied only through the by-pass 55 and open valve 46 to give an intermediate fire. Should room temperature rise unduly the lever 62 is then moved so that the roller 75 snaps over the cam peak 70 and moves valve 46 to its closed position. When the bulb 57 calls for heat, the roller snaps from the cam 71 to the cam 69 so that the valve snaps from full off to full on position. The device 64 may be removed from the unit body 10 and be replaced by an expanding wire thermal element actuating the valve through a compound lever system and being heated by a resistance wire connected to a thermial couple. In this case a spring loaded stop allows the thermal element to actuate the valve between full on and full off or between full on and intermediate fire.