SHELL-AND-TUBE HEAT EXCHANGER

Disclosed herein is a shell and tube heat exchanger including a shell having a cylindrical body, a pair of tube sheets installed to divide the inside of the shell and provided with a plurality tube insertion holes formed therethrough so as to face each other, and a plurality of tubes respectively welded to the tube insertion holes facing each other to connect the tube sheets, and further including a plurality of tube joint members having the same diameter as that of the tubes and respectively inserted into the tube insertion holes of the tube sheets, and a plurality of ring wires manufactured by cutting a welding wire having a long length into pieces having a designated length and bending the pieces into a ring shape and inserted into the outer circumferences of both ends of the tubes, wherein ring-shaped tube sheet grooves spaced from the tube insertion holes by a designated distance in the outer circumferential surface are formed on each of facing surfaces of the tube sheets so as to form joint parts, both ends of the tubes are inserted into the tube insertion holes of the tube sheets facing each other such that both ends of the tubes contact one end of each of the tube joint members facing the ends of the tubes and are located within the recessed distance range of the tube sheet grooves, and the ends of the tubes together with the tube joint members and the joints are welded to the respective tube sheets by a welding torch inserted into each of the tube joint members using the ring wires as a filler metal.