| 摘要 |
PURPOSE:To maintain a large heat transfer area for improving the heat transfer capacity by forming pipe-peripheral direction grooves closer to central side of the surface of a pipe than pipe-axial direction grooves, and connecting the pipe-peripheral direction grooves each other through tunnel-like holes that are formed at intersecting points of the pipe-axial and pipe-peripheral direction grooves. CONSTITUTION:A large number of pipe-axial direction and pipe-peripheral direction grooves 11 and 12 are provided on the exterior surface of a heat transfer pipe 10. The pipe-peripheral direction grooves 12 are formed closer to central side of the pipe, i.e., in a deeper position, than the pipe-axial direction grooves 11. Each of fins 13 is reduced in its width and thickness towards its top so as to form a protruding pin of a pyramid shape, and they are arranged in the pipe-axial direction in rows across the pipe-peripheral direction grooves. The exterior heat transfer surface area of the heat transfer pipe 10 is increased by a large number of the fins 13, causing an increase in the evaporation capacity. Penetration holes 20 of a tunnel- like shape are provided under the pipe-axial direction grooves 11 at positions where the pipe-axial and peripheral direction grooves 11 and 12 intersect each other, and the pipe- peripheral direction grooves 12 are connected each other through the penetration holes 13. As the flow of refrigerant in the pipe-peripheral direction is restrained by the penetration holes 20 provided on the pipe-peripheral direction grooves 12, the spread of refrigerant in the pipe-axial direction is promoted. |
