| 摘要 |
Provided is a pipe having a grooved inner surface, which has excellent thermal conduction properties, can be made compact and lightweight, and allows resources to be conserved. Also provided are a method and apparatus for producing this pipe having a grooved inner surface, which allow efficient and stable production thereof. The apparatus which is used for producing the pipe having a grooved inner surface is provided with: diameter-reducing means for drawing a base pipe in order to reduce the diameter thereof, and groove-forming means for forming a large number of grooves on the inner surface of the base pipe. If, for example, the angle of twist of a groove with respect to the centre axis of the pipe is ß (º) and the apex angle of a fin which is formed between adjacent grooves is a (º), then ß is between 30 and 60 and a is between 5 and 20. If the outer diameter is D (mm), the groove depth is H (mm), and the cross-sectional area with respect to the axial direction of the pipe is Ac (mm2), then D is no greater than 6, H is at least 0.07, and Ac < 0.8 × D. |
