Plate heat exchanger and refrigeration cycle system including the same

Abstract

Provided is a heat exchanger capable of enhancing long-term reliability of the device through prevention of leakage of a fluid while being excellent in heat exchange efficiency, simple in structure, and manufacturable at low cost. The heat exchanger includes a plurality of heat transfer plates, a plurality of inner fins, and a plurality of leakage preventing plates. Each of the leakage preventing plates has formed therein passage holes through which the fluid is caused to flow. An inner fin of a first channel and an inner fin of a second channel are provided so that the thermal resistivities of two fluids are kept equal to each other.

1 - 7 . (canceled) 
     
     
         8 . A plate heat exchanger, comprising:
 a plurality of heat transfer plates each having a flat heat transfer surface; and   a plurality of inner fins each being arranged in corresponding one of first channels or corresponding one of second channels, the first channels and the second channels being alternately formed between pairs of the plurality of heat transfer plates, respectively,   one of the plurality of inner fins, which is arranged in the corresponding one of the first channels, and another of the plurality of inner fins, which is arranged in the corresponding one of the second channels, being provided so as to have different heat transfer areas,   each of the plurality of inner fins being structured such that projections and depressions are formed repeatedly, the projections and the depressions having flat end portions, each of the plurality of inner fins being brought into surface contact with corresponding one of the plurality of heat transfer plates at the flat end portions.   
     
     
         9 . A plate heat exchanger according to  claim 8 , further comprising leakage preventing plates arranged between the pairs of the plurality of heat transfer plates, respectively, a passage hole through which at least a first fluid or a second fluid is flowed, is formed on each of the leakage preventing plates. 
     
     
         10 . A plate heat exchanger according to  claim 9 ,
 wherein the each of the leakage preventing plates has a flat portion in a region mated with the flat heat transfer surface of the corresponding one of the plurality of heat transfer plates, and   wherein each of the plurality of heat transfer plates and the each of the leakage preventing plates are brought into surface contact with each other so as to hold each other.   
     
     
         11 . A plate heat exchanger according to  claim 9 , wherein the each of the plurality of inner fins is brought into surface contact with corresponding one of the leakage preventing plates at the flat end portions. 
     
     
         12 . A plate heat exchanger according to  claim 8 , wherein the projections and depressions of the another of the plurality of inner fins, which is arranged in the corresponding one of the second channels, are smaller than the projections and depressions of the one of the plurality of inner fins, which is arranged in the corresponding one of the first channels. 
     
     
         13 . A plate heat exchanger according to  claim 12 ,
 wherein the each of the plurality of inner fins is structured such that the projections and depressions are repeatedly formed at substantially right angles over a width direction, and   wherein a pressure of a first fluid flowing in each of the first channels is higher than a pressure of a second fluid flowing in each of the second channels.   
     
     
         14 . A plate heat exchanger according to  claim 9 , wherein the each of the leakage preventing plates is configured to cover only a region in which the first fluid and the second fluid are adjacent to each other. 
     
     
         15 . A plate heat exchanger according to  claim 9 , wherein the each of the leakage preventing plates is formed of a cladding material. 
     
     
         16 . A plate heat exchanger according to  claim 9 , wherein a thickness of the each of the plurality of heat transfer plates and a thickness of the each of the leakage preventing plates are different from each other. 
     
     
         17 . A refrigeration cycle system, comprising the plate heat exchanger according to  claim 8 , which is provided in both or one of a condenser and an evaporator.