| 摘要 |
PURPOSE:To improve extremely the thermal efficiency without requiring a complex structure by a method wherein a burning gas is forcedly exhausted after blown against the object to be heated through a channel for permeating the inside of a breathable solid arranged at the periphery of a burner main body. CONSTITUTION:The high temperature burning gas generated by a burner main body 5 is blown against an opening top 2 and both sides thereof. At this time, due to the driving of an exhaust fan 9, the flow direction of the burning gas is changed after it is blown against the upper surface of members to be welded 1a, 1b, then the burning gas flows into a duct 6 after permeating a breathable solid 7 arranged to surround the burner main body 5, and is exhausted through the exhaust fan 9 via each of exhaust pipe 8a-8d. The burning gas before permeating into the breathable solid 7 is still kept at considerable high temperature, and accordingly, the both ends of the opening top 2 are heated by the radiation caused by the greater part of the thermal energy accumulated in the breathable solid 7 by the heating of the burning gas, the vicinity of the opening top 2 is sufficiently preheated. Therefore, by welding with a rack 4 moving along the opening top 2 as shown by an arrow mark Q, the adequate welding can be performed.
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