GB1320307A - Gas control system with thermo-electric ignition safety device - Google Patents

Abstract

1320307 Control system for gas-fired water heater JOH VAILLANT KG 13 May 1971 [25 May 1970] 14680/71 Heading F4T [Also in Division F2] A gas control system for a water heater comprises an ignition safety valve 3 in a fuel inlet 2, a control valve 16 mounted coaxially with a valve tappet 17 and pivoting handle 13, an ignition gas valve 11 mounted in an ignition gas duct 9 and an electromagnet 33 activated by a thermocouple in the ignition flame, so that when three cams 37 on the handle 13 are rotated from off-position ratchets 38 into ignition-position ratchets 62 of three cam tracks on a thrust member 40 a further cam 35 on the handle opens the ignition gas valve 11, and when a button 53 mounted in handle 13 is depressed the safety valve 3 is also opened to allow gas to reach the ignition burner while at the same time a pivoted lever 25 forces an armature plate 28 against magnet 33 where it is subsequently retained by the presence of an ignition flame thereby maintaining open valve 3 when button 53 is release#s and further rotation of handle 13 brings cams 37 into ratchets 63 under the force of a spring 41 which also thereby opens valve 16 allowing gas to reach the main burner via an outlet 64. If the ignition burner is extinguished, the magnet 33 releases the plate 28 thereby closing valve 3 under the bias of a spring 4, and this sequence may be intentionally initiated by turning back handle 13 closing in turn the control and ignition valves. The handle is axially restrained by a ring 34 and the button 53 may be depressed only in the ignition position of the handle when ribs 56 are aligned with grooves 57. A stop abutment 55 on the valve tappet 17 prevents release of the button 53 from its depressed position if the tappet becomes jammed, thereby preventing opening of the control valve and consequent passage of gas to the main burner. Fig. 5 shows an alternative arrangement of the constructional parts wherein the safety and control valves 78 and 80 and the valve tappet 89 are no longer coaxial with the pivoting handle 106 which is mounted on a thrust pin 102, and a rocker lever 100 with a clevis end 98 is employed to communicate between the two systems. Instead of having a button as 53, the handle itself can now be depressed to open the safety valve. A valve 74 is operable by an external screw 73 to adjust the gas inlet rate of flow.