DOUBLE-PIPE HEAT EXCHANGER AND HEAT-PUMP TYPE WATER HEATER

PROBLEM TO BE SOLVED: To provide a double-pipe heat exchanger having corrosion prevention means for preventing an outer surface part of an inner pipe in which refrigerant flows from being oxidation corroded with gas bubbles generated from hot water and provide a heat-pump type water heater including the double-pipe heat exchanger.SOLUTION: This invention relates to a double-pipe type heat exchanger 10 having an inner pipe 35 and an outer pipe 36 so as to perform a heat exchanging operation between first thermal medium flowing at the inner pipe 35 and second thermal medium flowing between the inner pipe 35 and the outer pipe 36 in which an outer surface part of the inner pipe 35 at a location corresponding to at least one of a feeding-out part 30a and a feeding-out part 30b of the second thermal medium is provided with a sleeve 40a acting as corrosion prevention means 40.SELECTED DRAWING: Figure 3 【課題】冷媒が流通する内管の外表面部が湯水から発生した気泡で酸化腐食するのを防止する腐食防止手段を設けた二重管式熱交換器及びこれを備えたヒートポンプ式給湯装置を提供すること、等である。【解決手段】内管３５と外管３６とを備え、内管３５を流れる第１熱媒体と、内管３５と外管３６との間を流れる第２熱媒体との間で熱交換を行う二重管式熱交換器１０において、第２熱媒体の導出部３０ａと導出部３０ｂの少なくとも一方に対応する部位の内管３５の外表面部に腐食防止手段４０としてのスリーブ４０ａを備えた。【選択図】図３