| 摘要 |
PROBLEM TO BE SOLVED: To provide an internally-grooved pipe and a method of manufacturing the same, free from degradation of heat transferring performance even when concentration of a refrigerating machine oil is high, and having high adhesiveness of an oil-repellent film and the internally-grooved pipe, with respect to the internally-grooved pipe for a heat exchanger. SOLUTION: In this internally-grooved pipe having fins on an inner face of the pipe, the film for preventing formation of an oil film of the refrigerating machine oil is formed on the inner face of the pipe to be used for a carbon dioxide refrigerant. A thickness of the film is 1-200μm, and a surface roughness Ra of the pipe inner face is 1-50μm. In this method of manufacturing the internally-groove pipe, a rolling process for forming a spiral groove on an inner face of a bare pipe, a charging process for charging an oil-repellent treatment agent to form the film, to the inner face of the internally-grooved pipe, a discharging process for discharging the oil-repellent treatment agent, a drying process for drying the inner face of the internally-grooved pipe, and a heating process for heating the internally-grooved pipe are successively performed in this order. COPYRIGHT: (C)2011,JPO&INPIT
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