GB2190717A

GB2190717A - Improvements relating to pipe fittings

Info

Publication number: GB2190717A
Application number: GB08612695A
Authority: GB
Inventors: Robert Anton Nelberg
Original assignee: F W Talbot & Co Ltd
Current assignee: F W Talbot & Co Ltd
Priority date: 1986-05-23
Filing date: 1986-05-23
Publication date: 1987-11-25
Also published as: GB8612695D0

Abstract

The present invention provides a support liner or ferrule 1. The support liner 1 is provided with a frusto-conical nose portion 2 which extends outwards from the main body of the liner 1. In use, the support liner 1 is inserted into the pipe 3 leaving the nose portion 2 protruding from the end of the pipe 3. The liner 1 is held secure within the pipe 3 by means of location nibs 4 and/or circumferential ridges. This modified liner 1 does away for the need for specialist bevelling and cutting tools and prevents damage to elastomeric sealing ring 6 located within pipe fittings 5. <IMAGE>

Description

SPECIFICATION Improvements relating to pipe fittings This invention relates to pipes and pipe fittings and in particular to an improved and modified pipe support liner. The invention is particularly adapted for use with plastics pipes and push-in type fittings.

Assembling a pipe fitting onto the end of a pipe is a skilled and time-consuming operation, since great care is required in order to avoid damage to an elastomeric sealing member which may be located in such a fitting.

These sealing members are often rubber '0' rings and they provide a fluid-tight seal between the pipe and the fitting.

If a pipe end is inadequately prepared before fitting, then damage to the sealing member occurs. For example, sharp edges and burrs can be left on the end of the pipe and these cut and/or tear the sealing member. Furthermore, if the pipe is inadequately prepared, or incorrectly inserted into the fitting, due to carelessness or confined conditions, then the sealing member may be displaced from its correct position or distorted in such a manner that it fails to provide a fluid-tight seal.

These problems are common to all types of pipes and fittings involving a sealing ring.

However, push-in type fittings which are commonly employed with plastic pipes, suffer from the additional disadvantage that insertion forces must be maintained with controllable limits. Furthermore, plastics pipes are prone to distortion in shape, thus making a fluid-tight seal difficult to achieve.

These problems have previously been overcome by carefully cutting and bevelling the pipe end to allow smooth insertion into the pipe fitting without damage to the sealing ring. The cutting and bevelling of the pipe is a skilled and time-consuming operation which requires special tools which are expensive to purchase and maintain.

It is known to maintain the pipe's shape by the use of a simple tubular support liner which is inserted into the (pipe fitting) end of the pipe prior to insertion into the fitting. These support liners are usually provided with an end flange which, in use, abuts the end wall of the pipe thus preventing the support liner from sliding into the pipe.

The present invention seeks to overcome these problems by providing a modified support liner. In particular, the present invention seeks to do away with the need for special tools to prepare the pipe end and to simplify pipe fitting assembly by allowing the fitter simply to cut off the end of the pipe approximately square, using a saw.

According to the present invention, we provide a pipe support liner, comprising a tubular body section which enters into and fits against the inside diameter of the pipe, and a nose portion, the maximum outside diameter of which is approximately equal to that of the pipe, and which increases from a minimum value at its tip to said maximum diameter where it abuts the pipe end.

Preferably, the liner is provided with a frusto-conical nose portion. Preferably, the maximum diameter of the nose portion is equal to or slightly less than the external diameter of the pipe.

The pipe support liner may be provided with one or more location nibs, which in use serve to maintain the support liner in position. Alternatively, instead of or additionally to said location nibs, one or more circumferential or part circumferential ridge's may be provided on the tubular body section for contact with the inside diameter of the pipe. The support liner may be made from metallic, plastics or reinforced plastics materials of appropriate rigidity and strength.

A preferred embodiment of the invention is now described with reference to the accompanying drawing which is an exploded view showing in cross-section a support liner located in position within a pipe end, and a portion of a pipe fitting within which the pipe end is to be located.

Referring to the drawing, a support liner 1 is provided with a smooth, frusto-conical nose portion 2, having a radiused cut end 2a and extending radialy outwards from the main body of the liner 1, which is located within a plastic pipe 3. The included angle of the cone formed by the frusto-conical nose portion would be advantageously between 30 and 80 and preferably about 50 . As can be seen, the nose portion 2 protrudes from the end of the pipe 3 and acts as a smooth end face masking any sharp edges or burrs that may be present on the end of the pipe 3.

The support liner 1 has a plurality of circumferentially spaced integral wedge-shaped location nibs 4 which are designed so as to bite into the inside bore of the pipe 3, thus preventing the support liner from becoming loose of displaced under its own weight. Alternatively, or additionally, a series of circumferential ridges may be used. Normally, the body of the liner 1 would slide without difficulty into the end of the pipe 3.

To assemble the pipe 3 within a push-in type fitting 5 provided with an elastomeric sealing ring 6, the pipe's end is cut approximately square with a hacksaw. The support liner 1 is then inserted into the pipe end until the locating nibs 4 bite and secure the liner 1 in position.

The pipe 3 is then pushed into the pipe fitting 5, so that the tapered nose portion 2 enters the elastomeric sealing ring 6 in a progressive manner. Its smooth tapering surface prevents any damage to the ring, whilst its frusto-conical shape and the progressive insertion action prevents the distortion of the ring and controls insertion forces. In fact, the modified support liner 1 acts as guide, ensuring the correct orientation of the pipe in the pipe fitting.

It will be understood that the above embodiment has been described by way of example only and modifications in detail can be made within the scope of the invention.

For example, the exact shape of the tapered nose 2,2a, could be altered.

Claims

CLAIMS 1. A pipe support Iiner,comprising a tubular body section which enters into and fits closely against the inside diameter of the pipe, and a nose section, the maximum outside diameter of which is approximately equal to that of the pipe, and which increases from a minimum value at its tip to said maximum diameter where it abuts the pipe end. 2. A pipe support liner as claimed in claim 1 wherein the largest diameter of the nose portion is equal to or slightly less than the external diameter of the pipe. 3. A pipe support liner as claimed in claim 1 or 2 which is provided with at least one location nib. 4. A pipe support liner as claimed in claim 3 wherein said location nib is a wedge-shaped member formed integrally with said pipe support liner. 5. A pipe support liner as claimed in claims 1 or 2 which is provided with at least one circumferential or partly circumferential ridge on the tubular body section to locate and hold the liner in the pipe. 6. A pipe support liner as claimed in any one of claims 1-5 which is made from metallic, plastics or reinforced plastic materials. 7. A pipe support liner substantially as hereinbefore described with reference to the accompanying drawing. CLAIMS New claims or amendments to claims filed 6n 2/6/87. Superseded claims 1-7. New or amended claims:

1. A pipe support liner for a push fit pipe coupling, comprising a tubular body section which enters into and fits closely against the inside diameter of the pipe, and a nose section, the maximum outside diameter of which is approximately equal to that of the pipe, and which increases from a minimum value, which is at least substantially the same as its inside diameter at its tip, to said maximum diameter where it abuts the pipe end.

2. A pipe support liner according to claim 1 which has a smooth radiused tip which merges with a frusto-conical face terminating in said maximum outside diameter.

3. A pipe support liner as claimed in claim 1 or 2 wherein the largest diameter of the nose portion is equal to or slightly less than the external diameter of the pipe.

4. A pipe support liner as claimed in claim 1, 2 or 8 which is provided with at least one axially extending location nib.

5. A pipe support liner as claimed in claim 4 wherein this or each said location nib is a wedge-shaped member formed integrally with said pipe support liner.

6. A pipe support liner as claimed in claim 1, 2 or 8 which is provided with at least one circumferential or partly circumferential ridge on the tubular body section to locate and hold the liner in the pipe.

7. A pipe support liner as claimed in any one of claims 1-6 which is made from metallic, plastics or reinforced plastic materials.

8. A pipe support liner substantially as hereinbefore described with reference to the accompanying drawing.