GB1246041A - Improvements in and relating to autogenous torches - Google Patents

Abstract

1,246,041. Gas torches. MESSER GRIESHEIM G.m.b.H. 7 March, 1969 [8 March, 1968], No. 12154/69. Heading F4T. A gas-fuelled welding or cutting torch is protected against flash-back damage by the provision of a fuel shut-off valve between a gas supply pipe and a mixing chamber, the valve being operable to shut off the gas supply under the influence of a pressure wave. Fig. 1.-Gas A flows past a diaphragm 19 and through passages 17, 13 to mix with oxygen S in mixing chamber 11. The mixture passes to a nozzle, a portion of it diffusing into storage chamber 22 via passage 23. On flash-back, the mixture in chamber 22 is ignited and the pressure rise moves diaphragm 19 to shut off the supply. Fig. 3.-To increase the delay before the valve 18, 19 re-opens, the entrance to storage chamber 22 may be closed by a spring-loaded non-return valve 25, a by-pass passage 32 being provided to permit the chamber to fill with oxygen-gas mixture. Fig. 4.-A piston 36, supported between springs 36, 39, blocks passage 40 into chamber 35. On flash-back, the pressure wave deflects piston 36 so chamber 35 fills with high-pressure mixture, then, as the wave abates, the mixture pushes the piston in the reverse direction to shut off the supply until the mixture pressure falls, due to leakage. Fig. 5.-A sliding sleeve 45 is moved by the influence of the pressure wave on flange 46, causing portion 50 to move between two sealing rings 52, 53. The valve is released manually by pressure on plunger 58. Fig. 6.-A spring-loaded piston 67 is held away from outlet 80 by engagement of collar 71 with edge 84 of spring-loaded detent 70. Slide 66, moved by the pressure wave, releases the detent, closing the valve, which is reopened manually using button 81. Fig. 7.-Flash-back pressure moves diaphragm 95, closing valve 91. Spring-loaded plunger 98 retains the valve closed until the pressure in chamber 89 has dropped to a considerable extent.