| 摘要 |
<p>PURPOSE:To provide a drain pipe by which the flowing sound of waste water is not heard loudly even when the waste water is flowed down in the pipe. CONSTITUTION:This drain pipe is composed of at least four layers. As inner layer is a hard synthetic resin pipe 1, on whose outside the resin sheet 2 layer containing a lead plate, lead fibre or lead is positioned, and further outside an air layer or a synthetic resin foaming body layer 4 partitioned by a ring 3 with a slit is positioned, while a metal pipe 5 is positioned in the outermost part. These four layers are integrated by the drawing process of the metal pipe 5 as the outer layer.</p> |
