| 摘要 |
A consumable electrode arc welding gun with provision for fume extraction and which is compatible with use of an inert gas atmosphere shielding the weld pool includes an electrically conducting contact tube 29 through which a consumable electrode wire 12 is fed. A nozzle 27 at the forward end of the gun surrounds a stick-out portion of the electrode wire. A fume extractor tube 51 surrounding the nozzle 27 is formed with an outwardly flared mouth 53 at its forward end which cooperates with a complementary portion 47 of the nozzle to define a circumferential fume inlet slot arranged to produce a peripheral field of depression oriented generally radially, a forward angle of about 26 degrees being preferred. Means is provided for applying suction to the space between the fume extractor tube 51 and the nozzle 27. Preferably shielding gas is supplied via flow passages 37 in a sleeve 25 of silicon nitride or other thermal shock resistant insulator to a cavity in the nozzle beyond the forward end of the sleeve 25. <IMAGE> |
