Patent ID: 7490658
Filing Date: 2009-02-17
Classification: F25B,F28F

Abstract:
1. An internally grooved heat transfer tube for a high-pressure refrigerant which is used for a cross fin tube type heat exchanger using a high-pressure refrigerant and which is formed of copper or a copper alloy, the heat transfer tube including: a multiplicity of grooves formed in an inner surface thereof so as to extend in a circumferential direction of the tube or extend with a predetermined lead angle with respect to an axis of the tube; and internal fins having a predetermined height and each formed between adjacent two of the multiplicity of grooves, characterized in that: t/D ranges from not smaller than 0.060 to not greater than 0.146 and d N/Di ranges from not smaller than 8 to not greater than 24 where a number of the multiplicity of grooves is represented as N and a maximum inside diameter of the tube which corresponds to an inside diameter of the tube formed by connecting bottoms of the multiplicity grooves is represented as Di.