To provide a multiple pipe-type heat exchanger capable of reducing probability of electric corrosion, and detecting water leakage before electric corrosion.
This multiple pipe-type heat exchanger is composed of a copper inner pipe 1 provided with a leakage detecting groove 4 on its outer surface, an aluminum outer pipe 2 covering an outer wall of the inner pipe 1 and composed of a number of refrigerant flow channels 3, an outer pipe terminal portion 5 disposed at a longitudinal end portion of the outer pipe 2 and having an inner peripheral part close to the inner pipe 1, and longer than an outer peripheral part of the outer pipe 2, and a branch portion 7 having a circular passage 6 corresponding to the refrigerant flow channels 3 and joined to the outer pipe terminal portion 5. A longitudinal end portion of the inner pipe 1 is longer than a longitudinal end portion of the outer pipe 2, a boundary between a tip of the outer pipe terminal portion 5 and the end portion of the inner pipe 1 is covered by a stretch heat shrinkable tube 8, and the leakage detecting groove 4 is formed by the halfway of the part covered by the heat shrinkable tube 8, thus the probability of electric corrosion of the aluminum outer pipe can be reduced, and the probability of flowing of components of refrigerating machine oil and the like existing in a CO2 refrigerant flow channel into a water side can be reduced.
Hiroki Naito
Daisuke Nagano