| 摘要 |
PURPOSE:To obtain a heat insulation pipe of high quality which is excellent in heat insulation by such an arrangement wherein a layer of foam urethane U is uniformly formed around the whole circumference of a pipe by injecting urethane liquid into a skin layer S through plural injecting holes arranged symmetrically around the main body P of the pipe. CONSTITUTION:A skin layer S which is protruded forward and formed by a crosshead 11 is sized by a sizing die 13 and then cooled. A pipe main body P is inserted into the skin layer S through a passing hole 21, and it forms a circular space in the skin layer S. Into the circular space, unprocessed urethane liquid is continuously injected from a ringlike nozzle 18 and a layer of foam urethane U is uniformly formed around the whole circumference. The unprocessed urethane liquid is caused to foam in the course from the crosshead 11 to a take-up machine 15, and the heat insulation pipe covered with the urethane layer U and skin layer S is drawn out by the take-up machine 15. |
