Drill-collar narrow-gap welding gas protection device

The utility model discloses a drill-collar narrow-gap welding gas protection device. A protection air inlet pipe is connected with a protection cover, a welding gun is installed on the lower portion of the protection cover and located in a welding seam of a drill collar, two idler wheel supports are symmetrically installed outside the protection cover and are fixed by two idler wheel support fixing devices, the positions between the idler wheel supports and the idler wheel support fixing devices are regulated by locating screws, idler wheels are installed below the idler wheel supports and make contact with the surface of the drill collar, the two idler wheels are symmetrically located on the two sides of the welding seam of the drill collar, a heat-insulating sleeve is installed between the protection cover and the idler wheel supports, the two idler wheels can freely roll along with rotating of the drill collar, vibration of the protection cover can be effectively slowed down, the two idler wheel supports can float on the idler wheel support fixing devices, a welding gun head can be freely lifted up along with rising of a welding layer, but the two idler wheels still roll stably, working of the protection cover is not affected, the drill-collar narrow-gap welding gas protection device can ensure that protection gas stably and effectively covers the welded surface, the welding arc track can not be affected, welding quality of the drill collar can be ensured, and the drill-collar narrow-gap welding gas protection device has remarkable economic benefits.