Indoor large storage tank upside-down mounting device

The utility model discloses an indoor large storage tank upside-down mounting device which is characterized in that a tank body is welded in a layered manner by adopting an upside-down mounting method, each tank section of the tank body is lifted along with a chain block on a hoisting column, personnel and equipment are all on the ground, and a channel steel expansion ring is adopted to guide the tank section to be lifted and guide the next tank section to be welded. The lower portion of the channel steel expansion ring is connected with a positioning plate, and an operation gap is formed between the positioning plate and the channel steel expansion ring. In the construction process of the next tank section, the procedure of welding the positioning plate on the tank section above the welded junction of the splicing seam is reduced, the reserved operation gap facilitates welding construction of the inner side and the outer side of the splicing seam of the tank section, the procedure of welding the wall plate o