Patent GB-1101908-A (GB)
Title: Safety device of the thermoelectric type for gas burners
IPC: G05D23/00
Filed: 1967-01-10
Abstract: 1,101,908. Valves. P. DE STEFANI and G. DE STEFANI, [trading as SOCIETA' ITALIANA TECNOMECCANICA "LA PRECISA" DI P. & G. DE STEFANI]. 10 Jan., 1967 [14 Jan., 1966], No. 1376/67. Heading F2V. [Also in Division F4] A safety device for use with gas burners comprises two gas control valves 20, 21 and 38, 39 closed by depressing push buttons 7 and 6 respectively, and a thermo-electric safety valve 17, 18 which is adapted to receive current from a thermo-electric joint arranged adjacent a pilot burner and may also be opened by depressing button 7, the two control valves being capable of closing chambers 9a and 37 which supply gas to the main and pilot burners respectively, and wherein depression of button 6 automatically depresses button 7 and both remain depressed until safety valve 17, 18 closes and releases them. To ignite the burner, button 7 is depressed closing valve 20, 21 which supplies gas to the main burner and causing the end 22a of stem 22 to open valve 17, 18 against spring 16. Gas flows from inlet 8 via passage 36 and chamber 37 to the pilot burner where it is ignited. Current from the adjacent heated thermo-electric joint energizes electromagnet 12 attracting armature 14 thus retaining open the valve 17, 18. Release of button 7 causes valve 20, 21 to open, and gas to pass to the main burner where it is ignited by the pilot burner. To close down the burner, button 6 is depressed which simultaneously depresses button due to interengagement of flange 7b in recess 35. Both valves 20, 21 and 38, 39 are thus closed and the supply of gas to both burners ceases. The buttons are retained in their depressed positions until the thermo-electric joint cools and the magnet 12 is de-energized. Armature 14 is then released and the valve member 17 moves upward under the effect of spring 16 to close aperture 18. Also the end 17a of stem 15 will contact the end 22a of stem 22 and cause both buttons to return to their outward position. The mechanism which retains the buttons in their depressed positions comprises a lever 57 pivoted at 56 and having a part 57a in contact with a ball 68 retained in a bore 69 such that it is in contact with the valve stem 22 of button 7. When button 7 is in its outward position an enlarged diameter portion of 52 of stem 22 is opposite the ball 68 and the end 57b of the lever abuts portion 47 of the stem extending from button 6. When button 7 is depressed the lever still remains in this position. When both buttons are depressed a narrow portion 54 of stem 22 comes opposite ball 68, the ball moves inwards to contact this portion and lever 57 pivots such that its end 57b enters a reduced diameter portion 47a of the stem depending from button 6, thus holding the buttons in their depressed position. When the end 17a of stem 15 contacts the end 22a of stem 22, the latter stem moves up an idle stroke equal to distance A such that portion 52 is adjacent the ball 68 and the lever is freed enabling both buttons to return to their outward positions. The lever is biased by a spring 58 anchored to a plate 61 which extends between the two buttons. Stem 22 is provided with a seal 72 having an annular base and a sealing lip with an inner semi-toroidal surface and an outer frusto-conical surface.