GB1420712A - Thermo electric ignition safety device - Google Patents

Abstract

1420712 Burner control JOH VAILLANT KG 11 Jan 1974 [8 March 1973] 01468/74 Addition to 1317535 Heading F4T The thermoelectric ignition safety device of the parent Specification is modified in that the lever 8 for operating the pilot gas valve 5 has an extension 8<SP>11</SP> acting on the switching lever 15 and also has two pivots 25, 26 for respective levers 27, 28. The latter are provided with cams 29, 30 and form a release linkage actuatable by a shut-down button 21. The device is shown in Fig. 2 in its operative state wherein the heat of the pilot flame is used to thermoelectrically energize the magnet 19 which then holds the assembly of levers in the position shown in which the microswitches 16 are closed to energize a circulation pump and the main gas valve. In this position the cams 29, 30 are in abutment with one side of a spring abutment disc 20 carried by rod 18 attached to the armature of the magnet. However, when the shutdown button 21 is depressed it acts directly on portion 37 of lever 28 and indirectly on lever 27 via a tongue 36, to cause both levers 27, 28 to rotate about their pivots 25, 26 against the restoring action of leaf springs 40, 41, whereby the cams 29, 30 are moved away from each other and radially away from the disc 20, as shown in Fig. 7, to release the lever assembly from its coupling with the armature rod 18. Thereafter the lever assembly moves about pivot 9 into an inoperative position wherein the microswitches are opened and the pilot and main valves closed. On subsequent automatic release of the rod 18 by the magnet 19, spring 17 forces the rod 18 and disc 20 leftwards so that the periphery of the disc abuts cam surfaces 34, 35 on the cams 29, 30 and forces the levers 27, 28 apart sufficiently for the disc to move back to its initial relationship with the cams 29, 30.