| 摘要 |
PROBLEM TO BE SOLVED: To improve pressure resistance while reducing path resistance, and make a heat exchanger usable for a CO2 freezing cycle. SOLUTION: An inflow pipe 10 is branched into four third inflow pipes 15 at branch tubes 12, 14, to each of which third inflow pipes an inlet end of a tube subunit 40 composed of an inner tube 41 and an outer tube 45. An outlet end of the tube subunit 40 is connected with a second outflow pipe extending from an assembly tube 22. Fins 50 to 52 are joinned between the tubes. A refrigerant passage is formed as a plurality of parallel passages, so that passage resistance is reduced to demonstrate high heat exchange performance while more reducing a passage hole in a surpain type refrigerant tube than the prior art to improve pressure resistance because the total passage cross sectional area is increased. Further, the refrigerant tube is prepared as a plurality of the same configuration tube subunits, so that cost is reduced with easy control.
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