| 摘要 |
<p>PURPOSE:To obtain a tough double wall pipe having a thin wall by forming the double wall pipe so that an outer pipe section is spirally wound on the outer peripheral surface of an inner pipe section in which a plastic band is wound and which consists of parallel outer pieces, inward inclined pieces and inner pieces. CONSTITUTION:A double wall pipe 1 consisting of an inner pipe section 2 and an outer pipe section 3 integral with the inner pipe. The inner pipe 2 is formed by spirally winding a plastic band having one part being overlapped and accordingly, is a smooth pipe-like body. In the cross-sectional view of the band, the band is composed of outer pieces 4 parallel with the axis of the inner pipe section 2, inward inclined pieces 5, 6 in pairs in which the inclined pieces are extended at an angle of 60 deg. from both ends of each outer piece 4 and abut against each other, and inner pieces 7, 7a which are extended from both ends of inward inclined pieces. The outer pipe section 3 is made of a plastic film or sheet which is spirally wound on the outer peripheral surface of the inner pipe section 2. As a result, it is possible to obtain a tough double wall pipe having a thin wall in its entirety.</p> |
