RETURN BENT TUBE, AND FIN AND TUBE TYPE HEAT EXCHANGER

摘要

PROBLEM TO BE SOLVED: To provide a return bent tube capable of enhancing condensation performance, capable of restraining evaporation performance from getting low, and capable of enhancing reliability in a joining part between a heat-exchanger tube (hair-pin tube) and the return bent tube, and a fin and tube type heat exchanger using the return tube. SOLUTION: In this return bent tube 1 of the fin and tube type heat exchanger 20 supplied with a coolant in a tube inside, and provided with the hair-pin tube 11, the return bent tube 1 having a tube main body part 1a connected to a tube end of the hair-pin tube 11, and a large number of fins 21a juxtaposed with a fixed space on an outer surface of the hair-pin tube 11, the return bent tube 1 is provided with the tube main body part 1a and a large number of the spiral first grooves 2 formed on an inner face of the tube main body part 1a, and a direction of the first groove lead angleθ1formed by the first grooves 2 and a tube axis is in the same direction as that of the second groove lead angleθ2formed by the spiral second grooves 12 formed on an inner face of the hair-pin tube 11 and the tube axis. COPYRIGHT: (C)2006,JPO&NCIPI