Portable arc welder - with cut=off valve near handwelding unit to prevent excessive waste of protective gas when welding stops

摘要

Portable MIG/MAG or TIG welding machine with current; protective gas- and wire feed-sources has a remote controlled valve (6) between the gas source (9) and feed tube (7) for cutting off the gas flow when the welding is stopped. Near the weld burner (10) in the feed tube (7) is a back-flow cut-off valve (18) which is activated when the pressure in the tubing is below that of the work pressure of the gas. ADVANTAGE - Rapidly blocks off the gas flow from the tubing (7) when the welding is stopped without losing excessive gas. Also ensures immediate gas flow when welding is recommenced to protect the weld area.