| 摘要 |
<p>PROBLEM TO BE SOLVED: To restrain reduction in flattening strength, and impart flexibility by opening slits having a width being in a specific range of a wave pitch in a length of a specific range of the circumference along a valley part of a corrugated pipe. SOLUTION: Slits are normally arranged by a single piece and in a plurality when necessary in the circumferential direction of a valley part. The slits are not juxtaposed with an adjacent valley part going over a crest part, and when the slits are respectively arranged in plural valley parts, mutually adjacent slits are arranged so as not to completely overlap each other when seen through in the lengthwise direction of a pipe. A shape of the slits is formed in a long elliptic shape in the lengthwise direction of the slits so that a length running along the valley parts is set to 1/10 to 1/3 of an outer periphery of a corrugated pipe and a width is set to 1/50 to 1/5 of a wave pitch length of the corrugated pipe. Therefore, reduction in flattening strength is restrained, and flexibility is imparted, and piping can be easily bent.</p> |
