| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To further enhance a drain noise preventing effect by restraining or preventing air propagation sound as well as skeleton propagation sound of drain noise in a drainage collecting pipe made of metal. <P>SOLUTION: A composite covering layer 15 including a sound insulating layer is provided in an upper inflow port part 5 and a lower outflow port part 6 of a pipe body 7 in a surrounding state of the outer peripheral surface of the pipe body 7 including the upper inflow port part 5 and the lower outflow port part 6, excluding a required riser outer fitting area and a required mounting work area of pipe connecting accessory instruments. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
