Auxiliary device and method for compression of thermal insulation filler in fixed cylinder and positioning and welding of sealing cover

The invention discloses an auxiliary device and method for compression of thermal insulation filler in a fixing cylinder of a high-temperature gas cooled reactor steam generator and positioning and welding of a sealing cover, and the device and method are characterized in that firstly, loose cotton is pre-compressed into a cylindrical structure, and the density of the cylindrical structure is smaller than the required density after filling and compression; after being inserted into a fixing cylinder, the columnar heat preservation filler is compressed through an auxiliary device composed of an outer sleeve, an inner jacking pipe, a pressing block and a jackscrew, the pressing block is replaced with a sealing cover in the compression process, and then the sealing cover is welded into the fixing cylinder when the columnar heat preservation filler is compressed to a preset depth. Smooth spot welding of a welding gun and a welding wire and observation of a welding bead can be achieved through the unique design st