Arc-welding torch with improved sealing

摘要

The torch comprises a torch body (14) comprising a manipulation handle (12), and a curved tubular portion (5) that is fixed to the torch body and comprises an internal conduit. The internal conduit comprises, at its downstream end, a tubular lance torch with an axial internal passage. The tubular lance torch comprises, on its external surface, a threaded downstream region and an upstream region having a hexagonal external profile. An annular insulating part has an internal profile complementary to the external profile of the upstream region of the lance torch. The torch comprises a torch body (14) comprising a manipulation handle (12), and a curved tubular portion (5) that is fixed to the torch body and comprises an internal conduit. The internal conduit comprises, at its downstream end, a tubular lance torch with an axial internal passage. The tubular lance torch comprises, on its external surface, a threaded downstream region and an upstream region having a hexagonal external profile. An annular insulating part has an internal profile complementary to the external profile of the upstream region of the lance torch, and is arranged around the upstream area of the lance torch. A threaded nut part is screwed on the threaded downstream region of the lance torch. A water diffusing element has an annular shape, is formed with radial orifices, and is fitted on the lance torch between the annular insulating part and the threaded nut part. A first O-ring is arranged between the threaded nut part and the water diffusing element. A second O-ring is arranged between the water diffusing element and the annular insulating part. A spacer element is arranged between the first O-ring and the threaded nut part. The threaded nut part is directly or indirectly placed on the spacer element so as to push back it in the direction of the first O ring. The torch further comprises a support having a contact tube, a flue gas sensor comprising an internal passage and openings allowing the internal passage present in fluid communication with the outside of the torch, and a welding nozzle fixed to the curved tubular portion or flue gas sensor. The support is screwed at the threaded downstream region of the lance torch. The support is isolated from a nozzle by an isolating diffuser arranged between the support and the nozzle. The annular insulating part is nested in the upstream region of the lance torch. The flue gas sensor comprises an internal flange radially projecting towards the inside of the flue gas sensor. The threaded nut part is placed on the internal flange so as to push back it in the direction of the spacer element. The lance torch is pierced with two openings located between the upstream region and the threaded downstream region, and comprises two concentric tubes that are machined and assembled so as to form separated water circuits. The water diffusion element is positioned between the first and the second O-rings. Independent claims are included for: (1) a welding installation; and (2) a process for welding an electrical arc.