| 摘要 |
<p>PURPOSE:To form an air core all the time in the center of a pipe so as to contrive reduction of noise with no blinding by forming an inner side shape of a pipe section, cut in a direction orthogonal to a pipe axis, into polygon and its top part into a helical shape. CONSTITUTION:A drain pipe 1 shapes its section, cut in a direction orthogonal to an axis of the pipe, into a polygonal ring and also twists gradually in the pipe axial direction so as to form a helicoid. Each polygonal top part 2 in an internal side of the pipe is chamfered respectively in a curved surface shape. Material of the drain pipe 1 is synthetic resin of polyvinyl chloride, polyethylene, polybutene, polypropylene, etc, and these fiber reinforced resin and cast iron or the like. As a result, drain water is collected in the vicinity of the polygonal top part of the section in the pipe and allowed to flow down helically along the top part, and blinding of the drain pipe is eliminated without stopping dust, fiber chip, etc., contained in drain water, while forming an air core in the center of the pipe.</p> |
