GB762435A - Safety device for gas burners - Google Patents

Abstract

762,435. Lamp failure alarms. JUNEAU, A., and JUNEAU, E. Sept. 8, 1954, No. 26050/54. Class 118 (2). An electrical indicating system combined with one or more gas burners (not shown) comprises a gas pressure operated main switch 5, 6 controlling the supply of current to a first and a second signal circuit, the first signal circuit including a signal device such as a lamp 19 and being completed for a predetermined time at starting by a time switch 17, a series switch 15 closed by opening a gas burner supply valve 11 and a thermal switch 16 which is eventually opened by the heat of the gas burner, and the second signal circuit including a signal device such as a lamp 20 and being completed at starting and during running by a series switch 15 closed by opening a gas burner valve 11. There is one switch 15 and one thermal switch 16 associated with each burner. At starting of any one burner the movable arm 25 of the time switch 17 contacts the contact 27 to energize the lamp 19 and the switch 15 of that burner is closed by opening its gas valve 11. Afterapredetermined time the arm 25 breaks contact with the contact 27 and makes contact with a contact 26 connected to an alarm bell 18 which is therefore energized if the thermal switch 16 has not opened its contacts in consequence of the burner being ignited. The main switch 5, 6 is operated by a plunger 2 having two pistons 12, 12<SP>1</SP> slidable in a cylinder 1 having a gas inlet 7 and two lateral ports 8, 9 communicating with a pipe 10 leading to the burners. When the gas valves 11 of all the burners are closed the gas pressure in the pipe 10 holds the plunger in the position closing the inlet 7 but when a gas valve 11 is opened the pressure in the pipe 10 is reduced and the plunger moves to the right against the action of a spring 4 to connect the gas inlet 7 with port 8 and to close the main switch 5, 6. The alarm bell 18 may also be energized through the main switch 5, 6 and through contacts 21, 22 which are closed when all the burners are out of use, the main switch 5, 6 in this case closing if a gas leak occurs in the pipe 10. The contacts 21, 22 are opened by an electromagnet 14 when a gas valve 11 is opened.