Patent GB-806543-A (GB)
Title: Improvements in flame failure control units
Inventor: EVES ERNEST WILLIAM
IPC: F23Q9/14
Filed: 1955-12-20
Abstract: 806,543. Controlling gas burners. PEEL CONTROLS Ltd. Dec. 20, 1956 [Dec. 20, 1955], No. 36468/55. Class 75(1) In a flame failure control apparatus for burners comprising (1) an electromagnet and armature assembly 2 energized by a thermosersitive element, such as a thermocouple or a thermal switch, irradiated by a pilot burner, (2) a movable member 9 adapted to be displaced by separation of the armature from the electromagnet, on failure of the pilot burner, to cut off the supply of fuel to the main burner and (3) a manual reset control by which the electromagnet and armature assembly can be reset, in order to control more than one burner a number of electromagnet and armature assemblies 2, one for each burner, are grouped so that they operate on a common movable member 9 displaceable to a fuel cut off position by separation of any one armature from its electromagnet, a single manual reset control 21 being provided for resetting both the movable member and the electromagnet and armature assemblies. The electromagnets and armatures are mounted with their axes vertical in casings 4 in a housing 1. Each armature is secured to a spindle 6 projecting downwardly through a bushing in the base of its casing 4 and having a head 7 which bears on a strip of resilient material in the common movable member 9. A light spring 8 surrounding the spindle 6 ensures that the armature falls away from the electromagnet when the latter is deenergized. The common movable member 9 consists of a rectangular plate hinged at its rear edge by a horizontal pin 12 to the housing 1 and urged upwardly at its front edge by a spring 13 which is just strong enough to hoild the plate horizontal when none of the heads 7 on the armature spindles is resting on it. The reset control 21 comprises a spring-returned vertical push button, the upper end of which engages the plate 9 and is also secured to the free end of a hirged lever 19 adapted to operate a two-way switch 17. The plate 9 operates a further two-way switch 15. On pressing the push button upwardly the plate 9 and the lever 19 are raised whereby the switch 15 is actuated to close its upper contact, Fig. 3, to open an electrically operated pilot gas valve PV supplying all the pilot burners and the lever 19 actuates the switch 17 to close its upper contact and energize electrically operated igniting devices I for the pilot burners. If all the pilot burners ignite all the electromagnets are energized and on release of the push button the spring 13 holds the plate 9 in raised position but the lever 19 drops to change-over the contacts of switch 17 so that the igniters I are de-energized and an electrically operated main gas valve MV supplying fuel to the main burners is opened. In the event of flame failure at any one pilot burner the associated armature falls so that the head 7 strikes the plate 9 end forces the latter downwardly so that the upper contact of switch 15 is opened to de-energize both pilot and main fuel valves PV, MV and a lower contact is closed to energize an alarm or indicator A. In a modification, Fig. 5 (not shown) a pilot gas control valve is mounted above the plate 9 and connected mechanically thereto so as to be opened when the plate is raised. The switches 15, 17 control only the main valve, igniter and the alarm. In the construction shown in Fig. 4 the plate 9 is coupled directly to a main gas valve 23 and a co-axial pilot gas valve 24 mounted on a single valve stem and the push button engages the main valve 23. The pilot valve 24 may be replaced by a switch for operating an electromagnetic pilot valve for all the pilot burners or a separate electromagnetic pilot valve for each pilot burner. In the modified construction shown in Fig. 6 the electromagnets 3 are secured to a presser bar 27 and the armatures 5 rest on the plate 9. The switch 15 is mounted on the plate 9 and the switch 17 is mounted on the housing 1. The studs 29, 30 for operating the switches are carried by the presser bar 27. In operation the presser bar is pushed downwardly by means of the push button 21 to bring the electromagnets into contact with the armatures and to operate both switches. If ignition occurs the electromagnets are energized and when the push button is released the presser bar is raised by its spring 22 and the electromagnets raise the armatures. The switch 17 changes over its contacts to de-energize the igniter circuit and open the main fuel valve but the switch 15 does not change its contacts since it is held against its operating stud by the upward movement of the plate lever 9 under the action of its spring 13. Specification 762,855 is referred to.