| 摘要 |
PURPOSE:To prevent cooling water from scattering and local dents from developing and at the same time enhance cooling efficiency by a method wherein a nearly conical air jet is blasted against a sheathed running body from its whole peripheral direction and further nearly conical water jets are blasted against said running body from its whole peripheral direction on the downstream side of the air jet. CONSTITUTION:On the downstream side of the die 9 of an extruder 7, which extrudes a sheath 4 with a flat cross-section onto a plurality of tubes 2, a nearly conical air jet 17, which has the component of speed in the running direction A of a sheathed running body 11 continuously extruded from the die 9 of the extruder 7, is blasted against the outer peripheral surface of said running body 11 from its whole peripheral direction. Further, nearly conical water jets 18, each of which has the component of speed in the running direction A of the running body 11, are blasted against the running body from its whole peripheral direction on the downstream side of the air jet. Because the cooling water is blasted against the sheathed running body from its whole peripheral direction as described above, cooling is performed highly efficiently. In addition because the bubbles adhered onto the surface of the runner 11 are blasted away, no local dent develops. Further, the cooling water is hard to run in the direction opposite to the running direction of the running body 11. |
