Welding back protection device of nickel and nickel alloy welded tube

Welding back protection device of nickel and nickel alloy welded tube,there is one four-wheel dolly(1),the welded tube inner wall is hugged closely to four gyro wheels of four-wheel dolly,an installation fixed cover(2)on the four-wheel dolly,the one end of breather pipe(4)is fixed in fixed cover(2),the other end of breather pipe(4)lies in the welding region,be connected through the screw thread and the hole(5')of semi-circular tube(5)of two shutoff,the one end of copper pipe(6)is embedded on the inner wall of breather pipe(4), the other end of copper pipe(6)stretches out in the cavity of semi-circular tube(5),sets up copper pipe(6)aperture(6')in stretching out the cavity of semi-circular tube(5)on the pipe wall, it has overcover(7)to spread on semi-circular tube(5)upper portion. 镍及镍合金焊管的焊接背部保护装置，有个四轮小车（1），四轮小车的四个滚轮紧贴焊管内壁，在四轮小车上安装固定套（2），通气管（4）的端固定在固定套（2）内，通气管（4）的另端位于焊接区域，通过螺纹与两头封堵的半圆形管（5）的孔（5ˊ）连接，铜管（6）的端内嵌在通气管（4）的内壁上，铜管（6）的另端伸出到半圆形管（5）的空腔中，在铜管（6）伸出到半圆形管（5）的空腔中管壁上开设小孔（6ˊ），在半圆形管（5）上部铺有遮盖物（7）。