HEAT EXCHANGER

PURPOSE: To provide a heat exchanger in which the heat exchanging of low- temperature fluid after heat exchanging to rise the inside of an inner cylinder with high-temperature fluid before heat exchanging flowing to the outside of the inner cylinder is prevented. CONSTITUTION: A heat exchanger comprises an inner cylinder 1 disposed vertically in a vertical vessel 1, and a heat transfer tube 3 wound at the outside of the cylinder 2, wherein high-temperature fluid introduced from the upper part of the vessel 1 is lowered at the outside of the cylinder 2, heat exchanged with the tube 3 to become low-temperature fluid, inverted at the bottom of the vessel 1, and raised at the inside of the cylinder 2. An outlet tube 15 for taking out the low-temperature fluid fed inside the cylinder 2 from the upper part of the vessel 1 is inserted from above, the lower end 15x of the tube 15 is extended to the lower end 2x of the cylinder 2, both the ends 15x and 2x are connected, and a heat insulation layer 24 is formed between the tube 15 and the cylinder 2.