High-temperature-resistant convergent-divergent tubular heat exchanger

The utility model discloses a high-temperature-resistant convergent-divergent tubular heat exchanger, which belongs to the technical field of heat exchangers, aims to solve the problem of time-consuming and labor-consuming mounting and dismounting when a tubular heat exchanger breaks down, and comprises a moving ring, a plurality of groups of annularly distributed sliding blocks are fixed on the inner side of the moving ring, and the sliding blocks are connected on the inner side of a sliding chute in a sliding manner; the sliding grooves are formed in the left portion and the right portion of the outer side of the shell correspondingly and slidably distributed, and air cylinders are fixed to the front portions and the rear portions of the side walls, away from each other, of the two moving rings. When internal components of the tubular heat exchanger need to be replaced and maintained, the air cylinder is started to enable the output end of the air cylinder to contract, so that limitation on the movable ring