| 摘要 |
PURPOSE:To easily manufacture a heat transfer tube having a notched fin of excellent heat transfer efficiency, by wrapping a notchless, slender and band- shaped fin material around a heat transfer tube and fixing it to the tube, and forming notches by moving a cutter relatively in the axial direction of the tube. CONSTITUTION:A heat transfer tube 4, supported freely rotatably by a motor 2 and a speed reducer 3 placed on a table 1, is rotated in the direction of an arrow mark (a) and is moved, at the same time, in the direction of an arrow mark (b) while adding a tensile force, by a tension roller 6, while winding a notchless and long sized fin material 5 made of Al. Thus the material 5 is spirally and tightly wrapped around the tube 4 to be formed into a fin 5a, and the front and tail ends of the material are fixed mechanically. Next, notches 9, 9a,- are formed by cutting the fin 5a with a discoidal cutter 8, driven by 24 sets of motors rotating alternately in a reverse direction, while the tube 4 is moved. As a result, because the fin 5 is pushed by the cutter 8 to be slightly bent in the axial direction of the tube 4, the fin 5a is slightly bent zigzag by making notches 9, 9a,- as turnup boundaries, and then, a heat transfer tube having a desired notched-fin is obtained. |
