Corrugated plastic pipe sections having flanged ends and structurally tight joints thereof

Abstract

Corrugated plastic pipe sections having a flanged end formed by a circumferential portion of an end corrugation or section of the pipe liner and a method and kit for joining flanged end corrugated plastic pipe sections are described in a system in which a portion of the end corrugation or pipe liner forms a flange and a peripheral flange clamp straddles flanges and draws the flanges together to provide a structurally sound joint. A gasket may be interposed between flanges or the flange periphery and the clamp. The invention achieves a cost effective tight joint, allows field cuts of the corrugated plastic pipe and the fabrication of fittings from corrugated pipe sections and provides a selectable pipe size reducer coupling for corrugated plastic pipe.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001] This application is a continuation-in-part of my co-pending applications "Joint and Seal for Large Diameter Corrugated Plastic Pipe and Method for Joining Plastic Pipe Sections," Ser. No. 09 / 597,338 filed on Jun. 19, 2000; "Water tight Joint and Method of Sealing Drainage and Sanitary Sewer Pipe Sections," Ser. No. 09 / 788,913 filed on Feb. 19, 2001; and "Method and Joint Design for Infield Water Tight Sealing of Dual Wall Corrugated Plastic Pipe Sections," Ser. No. 09 / 794,638 filed on Feb. 27, 2001.BACKGROUND OF THE INVENTION[0002] Large diameter corrugated plastic (typically formed from polyethylene) pipe sections are known products. Past and present attempts to design water tight joints for corrugated plastic pipe to expand the use of the pipe to drainage and sanitary sewer applications typically involve radial compression of a gasket (molded or extruded and spliced) that occurs when an end section of the pipe formed as a spigot is ins...

AI Technical Summary

Benefits of technology

0010] The enhanced joint design and method of fabricating soil tight and water tight joints disclosed is cost effective, allows field cuts of corrugated plastic pipe, and simplifies in-plant fabrication of flanged end fittings from sections of corrugated pipe. A clamp is u

Problems solved by technology

The motion of pushing the gasket on the spigot in an axial direction and the frictional force on the interior lateral surface of the bell may cause the gasket to un-seat, twist and roll.

In addition, circumferential tensile stresses on the interior of the bell, required to maintain gasket compression, decrease the stress crack resistance of the plastic pipe.

In the prior case the stiffness of the corrugation is not sufficient to withstand the hydrostatic water pressure required to prevent water leaks.

Both solutions add considerable cost obtain a reliable water tight joint.

A further disadvantage of joints that utilize radial compressed gaskets is that the joints are subject to failure, leaking water under pressure, as a result of rolling and twisting of the gasket or by stress cracking of the bell.

However, the gasket transfers stress to the plastic inner wall or liner and to the corrugations.

Both the corrugations and the liner are relatively low in stiffness and have difficulty maintaining the radial compression of the gasket.

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