PURPOSE: To assure a prescribed shielding range with a small amt. of shielding gas and to reduce the comsumption of the gas by providing a device for heating the shielding gas to a prescribed temp. or above in the outlet of a nozzle.
CONSTITUTION: A shielding gas 9 to be admitted into a nozzle 2 through the gas hole 10 of a torch body 1 is heated by a heating element 7 so that the outlet temp. of the nozzle 2 attains ≥100°C. The heated gas flows out in the form of an expanded gas 11 through the outlet part 2a of the nozzle 2 to shield an arc and molten metal against air. If, therefore, welding is carried out under specific atm. pressure, the volume expands as the temp. of the shielding gas rises thus the prescribed shielding range of a low rate of the shielding gas is assured. Since the flow rate of the shielding gas can be decreased, the pressure fluctuation of the main pipe in a centralized piping system is decreased. The fluctuation in flow of the other torch is thus suppressed and the quality of welding is stabilized.
NAKAMURA HIDEO
MONNO YOUJI
