| 摘要 |
PURPOSE:To make the saving of fuel gas and reduction of required heating time possible by connecting burner elements respectively to flexible tubes having plural pieces of curved posture holding property connected at suitable intervals in the longitudinal direction of gas mixing pipes. CONSTITUTION:Two gaseous frame type heaters are disposed on both sides of pipes P, and their positions are fixed by using ground legs 6, 6. Respective burner elements 4, 4... are located in such a way that their ejection directions are made tangential or approximately tangential to the outside circumferential surfaces of the pipes by curving of flexible tubes 3, 3... having curved posture holding property. When the elements 4, 4... are ignited in this state, respective high temp. gaseous frames (f)... are flowed in contact with the outside circumferential surface of the pipe P whereby frames of a ring shape or an approximately ring shape are formed. In this way, the intended welding place on the outside circumferential surface of the pipes P is quickly and uniformly heated with less heat losses. |
