| 摘要 |
PROBLEM TO BE SOLVED: To provide an inner-grooved pipe used as heat transfer tubes built in air cooled heat exchangers for air-conditioners for domestic and business use, having improved heat transfer performance. SOLUTION: The inner-grooved pipe 1 comprises a set of grooved bands 2a provided in 180°-opposed regions on the pipe axis perpendicular cross section of the inner face of the pipe. The grooved bands 2a have trapezoidal grooves 4 and trapezoidal fins 3 extending in the pipe axial direction, and the trapezoidal grooves 4 get gradually shallow from the center of the grooved band 2a toward both sides P in the pipe peripheral direction. Groove lead angles formed by the trapezoidal groove 4 and the pipe axis are the same for each groove 4, 0-35°. The maximum height hmax of the fin is 0.05mm-0.30mm, a sloping angle is 0-50°, the groove bottom width of the trapezoidal groove 4 is 0.05mm-0.40mm, and the ratio (the upper bottom width/the groove bottom width) of the groove bottom width to the upper bottom width of the maximum trapezoidal fin 3max is 0.6-2.5. COPYRIGHT: (C)2006,JPO&NCIPI
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