CLH-II vertical Electrogas welder   is used for auto welding vertical seam for large storage tank in normal construction.the equipment ride on the edge of wall of tank and run along the shell to each of verticlal seam ,  It adopts special-purpose flux-cored wire protected by CO2. It also adopts the enclosed welding technique by cycling cooling water. The face of weld is directly in the way of the water-cooling slip shoe, while the back of weld uses the water-cooling copper shelter line or ceramic backing. The welding tractor runs along the stiff track with the welding gun and slip shoe, rising with the weld molten pool synchronically. These actions force the weld to shape in only one time by cooling water, which can obtain pretty appearance of weld and products with high quality.