GB2167146A

GB2167146A - Pipe coupling

Info

Publication number: GB2167146A
Application number: GB08429348A
Authority: GB
Inventors: Brian Rex; Francis Walter Davis
Original assignee: Victaulic Co PLC
Current assignee: Victaulic Co PLC
Priority date: 1984-11-21
Filing date: 1984-11-21
Publication date: 1986-05-21
Also published as: GB2167146B; GB8429348D0

Abstract

A pipe coupling includes an annular sleeves 5 fitting around the ends of two pipes 1,2, the sleeve having inwardly inclined end walls, an annular sealing member 7 encircles the pipe at each end of the sleeve. Flange members 10 provided at each end of the sleeve having an inward wall 12 portion provides support for an axially outer wall 9 of the adjacent sealing member. At least one pipe gripping member 17 is secured to the radially inner face of each annular sealing member. In operation the inward wall portion of the associated flange member bears upon the axially outer wall portion of the pipe gripping member and the axially outer wall of the sealing member, providing a compression seal of the sealing member with the pipe and the sleeve, and forcing the projection on the radially inner face portion into biting engagement with the wall of the pipe to be connected. <IMAGE>

Description

SPECIFICATION Improvements in or relating to pipe couplings and pipe joints formed therewith This invention relates to pipe couplings and pipe joints formed therewith, and more particularly the invention relates to such couplings and joints for the end to end connection of plain ended pipe.

It is to be understood that by the word "pipe" as used herein is included any pipe-like member such as pipe, tube and hose and hollow pipe fittings used in pipe-work such as elbows, "T" junctions, end members and valves for example.

Pipe couplings have been known for many years for plain ended pipes, including an annular sleeve adapted to be fitted around the ends of the two pipes, to be connected, the sleeve having inwardly inclined end walls, an annular sealing member for encircling a pipe to be connected at each end of the sleeve and having a portion adapted for fitting within the space between the inclined portion of the end walls and the outer walls of the pipe such as to constitute a sealing wedge directed inwardly axially of the sleeve.Flange members are provided at each end of the sleeve, the flange members each having a cylindrical portion overlying the ends of the sleeve, and end wall portions extending radially inwardly and outwardly of the cylindrical portion, the inward wall portion providing support for an axially outer wall of the adjacent sealing member, and the outward wall portion receiving connecting means from the other flange member for linking the two flange members together so that they can be urged together in use to provide axial forces upon the two sealing members whereby the wedge portions of the sealing members are forced inwardly between the inclined rear walls of the sleeve and the outer peripheral walls of the pipes, thereby providing a compression seal with the pipes.

Couplings of the kind described in the foregoing paragraph are hereinafer referred t as "couplings of the kind referred to".

Couplings of the kind referred to have proved over many years to be of ease in assembly and great reliability in performance in providing a compression sealed joint between pipework of various kinds.

However, couplings of the kind referred to do suffer from the disadvantage that they are not intrinsically locked couplings, and can become disconnected in use if, for example, the pipes are subjected to outward axial forces of a magnitude greater than the frictional grip between the sealing member and the pipes.

It is an object of the present invention to overcome or at least substantially reduce the above mentioned problem.

According to the invention there is provided a pipe coupling of the kind referred to in which at least one pipe gripping member is secured to the radially inner face of each annular sealing member and extending to the axially outer wall thereof so as to be essentially flush with the radially inner face and the axially outer wall of the sealing member, the pipe gripping member being provided with at least one projection on the radially inner face portion thereof such that in operation the inward wall portion of the associated flange member bears upon the axially outer wall portion of the pipe gripping member and the axially outer wall of the sealing member, providing a compression seal of the sealing member with the pipe and the sleeve, and forcing the projection on the radially inner face portion into biting engagement with the wall of the pipe to be connected.

A plurality of pipe gripping members may be provided spaced apart around the annular sealing member. In an alternative arrangement the pipe gripping member may be in the form of a ring, which may be split, bonded around the annular sealing member.

The gripping member or members may be secured to the sealing members by bonding for example.

The or each pipe gripping member may be provided with a plurality of projections or teeth of elongate form extending in a direction around the sealing member.

In a preferred embodiment of the invention for the connection of pipes of plastics material such as polyethylene, for example, the or each gripping member may be formed of a plastics material such as nylon for example.

The pipes, particularly where they are of plastics material, may be provided with internal strengthening ferrules in their adjacent ends.

The invention includes within its scope joints formed with couplings as herein defined.

In order that the invention may be more readily understood, one embodiment thereof will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a section through a coupling in use for joining two plain ended pipes in accordance with the invention; and Figure 2 is a front elevation of the sealing ring used in the coupling of Fig. 1.

Referring now to the drawings, it will be seen that the joint is formed from two polyethylene pipes 1 2 of plain ended configuration located closely adjacent in a end to end configuration. The ends of each pipe are provided with internal metal strengthening ferrules 3, 4 of a metallic or plastics material for example.

About the pipes is located a coupling comprising a cast iron sleeve 5 spanning the two pipes and having a radially inclined end face 6 at each end. Disposed at each end of the coupling and fitting within the radially inclined end face thereof is a resilient elastomeric sealing ring 7 having a wedge shaped axially inner portion 8, and an axially outer portion 9 adapted to receive and transmit to the wedge shaped portion compressive forces applied during make-up of the coupling and joint. Located about each end of the sleeve and sealing member is a cast iron flange 10 having a cylindrical portion 11 overlying radially the end of the sleeve and the sealing member, a radially inner portion 12 bearing upon the axially outer portion 9 of each of the sealing members, and a radially outer portion 13 carrying a plurality of apertures 14 there around for the receipt of bolts 15 and nuts 16.It should be noted that the sleeves and flanges can be of materials other than cast iron, such as of steel for example.

As can be seen the sealing rings each incorporate, spaced around them a plurality of toothed gripping members 17 of nylon. The gripping members bonded to the axially outer portion 9 of each sealing ring 7 and have a double serrated toothed face 18 generally flush with the radially inner wall 19 of the sealing ring, and an axially outer end 20 flush with the axially outer wall of the sealing member 7 so as to bear against an axially inner wall 21 of the radially inner portion 12 of the cast iron flange 10.

In operation, the coupling is assembled in a perfectly normal manner associated with this kind of coupling in that the flanges 10, sealing member 7 and sleeve 5 are loosely located about the joint between the pipes, the bolts 15 inserted and then tightened. Upon tightening of the nuts 16 on the bolts 15 not only are the wedge portions of the sealing members 7 forced into the wedge shaped spaces between the ends of the sleeves 6 and the pipes 1, 2, creating a highly efficient compression seal, but also the flanges bear upon the axially outer walls 20 of the gripping members forcing them, axially along and radially inwardly under pressure from the sealing members 7 so that the teeth at the radial inner 20 face 18 thereof bite and engage with the pipe forming a locked joint. By increasing the end load by further tightening the nuts 16 upon the bolts 15, the inserts are further forced into the pipe but with minimum movement.

The restraining properties achieved by means of the inset gripping members can be achieved of course on varying pipe outside diameters, wall thickness and offered angles.

The arrangement can be used on varying pipe diameters by displacement of the elastomeric material of the sealing members between the gripping members during the increasing compression forces on assembly and tightening of the coupling. The position of the teeth on the radially inner surface 19 of the sealing ring 7 ensures constant tooth engagement into the pipe surface.

Again, the freedom of positioning of the sealing ring allows the connection to be dismantled without the use of any special condition and, depending on its condition, re-used on a new location.

Claims

1. A pipe coupling of the kind referred to in which at least one pipe gripping member is secured to the radially inner face of each annular sealing member and extending to the axially outer wall thereof so as to be essentially flush with the radially inner face and the axially outer wall of the sealing member, the pipe gripping member being provided with at least one projection on the radially inner face portion thereof such that in operation the inward wall portion of the associated flange member bears upon the axially outer wall portion of the pipe gripping member and the axially outer wall of the sealing member, providing a compression seal of the sealing member with the pipe and the sleeve, and forcing the projection on the radially inner face portion into biting engagement with the wall of the pipe to be connected.

2. A pipe coupling as claimed in claim 1 wherein a plurality of pipe gripping members are provided spaced apart around the annular sealing member.

3. A pipe coupling as claimed in claim 1 wherein the pipe gripping member is in the form of a ring bonded around the annular sealing member.

4. A pipe coupling as claimed in claim 3 wherein the ring is a split ring.

5. A pipe coupling as claimed in any one of the preceeding claims wherein the or each gripping member is secured to the sealing members by bonding.

6. A pipe coupling as claimed in any one of the preceeding claims wherein the or each pipe gripping member is provided with a plurality of projections or teeth of elongate form extending in a direction around the sealing members.

7. A pipe coupling as claimed in any one of the preceeding claims for the connection of pipes of plastics material wherein the or each gripping member is formed of a plastics material.

8. A pipe coupling as claimed in claim 7 wherein the or each gripping member is formed of nylon.

9. A pipe coupling susbstantially as shown in and as hereinbefore described with reference to the accompanying drawings.

10. A pipe joint incorporating a pipe coupling as claimed in any one of the preceding claims.