Secured in Place Gasket for Sealing Plastic Pipelines, Method of Manufacture and Method of Installation

Abstract

A pipe sealing gasket is shown which is designed to be received within a raceway provided within a socket end of a female bell plastic pipe end which is assembled with a mating male pipe end to form a plastic pipe joint. The raceway in the female bell plastic pipe end is preformed during manufacture and the gasket is installed thereafter. The gasket has a rubber body portion which is reinforced by a hard plastic band formed as a series of integral, spaced wedges which are interconnected by a flexible ribbon. The hard plastic band acts to prevent extrusion of the gasket during a variety of pressure conditions as well as preventing displacement during field assembly.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates generally to sealing gaskets and sealing systems used for pipe joints in plastic pipelines in which a male spigot pipe section is installed within a mating female socket pipe section to form a pipe joint and, more specifically, to an improved gasket, simplified method of manufacture, as well as an installation method for installing a locked-in gasket within a preformed gasket groove in a section of pipe used to form a pipe joint.[0003]2. Description of the Prior Art[0004]Fluid sealing systems for plastic, fluid conveying pipes are used in a variety of industries. The pipes used in such systems are typically formed from thermoplastic materials including polyolefins and PVC. In forming a joint between sections of pipe, the spigot or male pipe end is inserted within the female or socket pipe end. An annular, elastomeric ring or gasket is typically seated within a groove formed in the socket en...

AI Technical Summary

Benefits of technology

The invention is a sealing gasket for PVC pipes that is made of rubber and plastic. It has a reinforcing element called a band that consists of a series of wedges connected by a flexible ribbon. This band is embedded within the gasket to improve its resistance to extrusion and displacement during field assembly. The gasket has a leading nose region reinforced by a hard plastic band that prevents extrusion and displacement of the gasket from the pipe. The gasket can be made from rubber or synthetic rubber like styrene butadiene rubber, ethylene propylene diene monomer rubber, or nitrile rubber. The hard plastic ribbon is made of a flexible plastic material that is rigid enough to prevent extrusion and displacement, but flexible enough to allow the gasket to accept inverse curvature during installation.

Problems solved by technology

Each of these solutions had critical limitations.

The plastic region in some cases, reduced the rubber surface contact area, sometimes leading to problems in providing the needed sealing in all conditions, including high pressure, low pressure and cyclic surges.

Poor bonding resulted in separation of the two elements.

The reinforcing band was subject to being misplaced and breakage in the two part system.

Thus, in some cases, the prior art solutions failed to provide the needed joint integrity, often contributing to the complexity and expense of the manufacturing operation and field installation.

Despite the advances offered by the Rieber process, the belling operation was somewhat complicated and costly.

Distributors and contractors cannot exchange Rieber process gaskets in their pipe inventory.

However, prior art gaskets with reinforcing elements are subject to breakage and are not easily bent or flexed by hand, thus generally precluding hand assembly in the field.

The size and position of the reinforcing element, which is bonded to the gasket body, generally was greater than the diameter of the mouth opening of the belled pipe end, presenting a further complication for assembly.

However, such a machine was fairly costly to construct and presented difficulties in being hand carried by a worker in the field.

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