GB2285665A - Pipe coupling for polyethlene pipes - Google Patents

Abstract

A coupling for joining lengths of polyethylene pipe 6 or for connecting such pipes to a fitting such as a gate valve 1 comprises a coupling member having a pipe receiving recess defined by a socket 4 surrounding an inner spigot 3. The recess has a seal 5 at its base. A tightening collar 11, urged towards the coupling member by tightening of nuts 9 on threaded rods 10, squeezes an elastic collar 7 against the outside of the pipe 6. Translational movement of tightening collar 11 also urges the pipe 6 against the seal 5. The elastic collar 7 may have formations 12 on its inner annular surface to assist in gripping the pipe 6. Optionally, socket 4 and tightening collar 11 have outwardly-tapering inner surfaces at their facing ends and the elastic collar 7 has a complementary external profile. <IMAGE>

Description

COUPLING FOR POLYETHYLENE PIPES DESCRIPTION OBJECT OF THE INVENTION The invention refers to a coupling for polyethylene pipings and, more precisely, to a specific configuration for a gate valve assembly, to be inserted within a polyethylene pipe, and to the pipe coupling elements for fixtures and pipings made of polyethylene.

The coupling consists of a sealing joint and an adjusting sliding collar, along with a tightening device. This latter pushes and presses such collar to achieve the water-tightness of the pipe against the joint apart from keeping the pipe sections against the valve assembly or pipe fittings.

BACKGROUND OF THE INVENTION The gate valves and the fittings for pipes and fixtures incorporate an element with means for coupling and connecting them to the pipe sections where such valve and/or the fittings have to be installed so that there are many types of couplings.

Among other things, this depends on the material of the piping as it happens with polyethylene in this case.

Up to now, while there are fittings for this kind of pipes all of them present different inconveniences that impair their correct installation.

In the case of installations with a pipe diameter up to 90 mm, there are injected polyethylene fittings while in the case of larger diameters - up to 200 mm - fittings are made from welded pipe sections which creates problems at the time of installation.

The connection of valves to such installations is another source of problems due to the fact that the system most widely used is to incorporate flanges to the valve ends.

Another element incorporating the so-called double chamber will be clamped to the previous assembly constituting the conventional coupling system for both PVC and polyethylene pipes.

Although the aforesaid system is considered to be efficient, it is also true to say that the installations which incorporate it are very expensive and difficult to assemble due to the existence of these heavy and expensive flanges, which are not totally necessary in the light of the usual extreme temperatures and pressures existing in the pipings using this kind of material.

DESCRIPTION OF THE INVENTION The coupling described in this report has been designed to solve all the above problems. For this purpose, either in the case of a gate valve or a fitting both include a special design so that the ends of the pipes to be assembled are directly coupled to these special configurations.

Specifically, the valve element or the fitting to be installed has to incorporate at the ends to be coupled to the pipe a grooved configuration determining an inner cylindrical section and another outer and smaller one so that the end of the pipe to be coupled should be directly introduced in such groove after inserting a sealing joint.

The coupling is complemented by means of an elastic collar, open radially, which is inserted between the pipe to be coupled and the inner edge of the outer section of the wall corresponding to the groove. Such collar should be pressed against the pipe sliding it through the groove to make the assembled pipe water-tight (elastic watertightness) and, furthermore, to fix it securely.

For this purpose, a series of nuts screwed on the rods incorporated on the relevant valve element or fitting act as pushing means. Such nuts should be screwed progressively and alternately.

This way it is possible to achieve a coupling in an easy and effortless manner since it suffices to connect the end of the pipe to be coupled to the groove of the valve assembly after placing the sealing joint.

Then the open collar is placed on the coupling area fixing and pushing it. This operation keeps the pipe section against the coupling and thanks to such pushing or sliding operation the water-tightness of the pipecoupling assembly is achieved by means of the elastic joint through the bolts screwed on the rods of the relevant valve element or fitting.

DESCRIPTION OF THE DRAWINGS To complement this description and in an effort to better understand the main characteristics of the invention, a set of drawings is attached to this descriptive report forming an integral part of it and where, as an illustra tion and without limitation, the following has been represented: Figure 1 shows a section view of a gate valve inserted and coupled between two opposed pipe sections through the coupling which is the object of this invention.

Figure 2 also shows a section view of a fitting for flanges and polyethylene pipe according to the object of this invention.

PREFERRED EXECUTION OF THE INVENTION In the light of figure 1 and according to the preferred execution described herein, it can be noticed how the coupling has been foreseen to be applied to gate valves which incorporate a tubular element (1) the relevant ends of which (2) have been axially lengthened incorporating a cylindrical section (3) and a ring-shaped outer flange (4) which forms a groove where the elastic joint (5) will be housed.

The end of the pipe (6) is inserted in this groove while the flange (4) remains outside. This flange presents a slight inner divergence to enable the positioning of the clamping collar.

This collar is formed by an open ring presenting an outer flat surface to slide inside the flange (4) of the groove and which in its ends presents two sections converging towards the centre of the outer face.

One of these sections can be introduced through the divergence created by the flange (4) while the other section supports the tightening nut (9) resting on a ring (8) screwed on a rod (10) the ends of which in turn are screwed to a "moyu" made on the valve element (1) itself and, specifically, in its ends. The rod (10) passes through a tab (11) and protrudes to receive the relevant rings (8) and tightening bolts (9) mentioned before.

The tightening collars (7) incorporate in the surface which will be placed on the pipe to be assembled (6) a series of notches (12) designed to improve the fixing and the strength.

The coupling is made according to the above procedure, i.e. after installing the sealing joint (5) in the groove located at the ends (2) of the element (1) of the valve, the pipe (6) to be installed is inserted in such groove and, then, the tightening collar (7) is placed between the side surface of the pipe (6) and the divergent section of the flange (4) which is the outer limit of the first part of the groove.

Then, the nuts (9) are screwed and - pushing the tab (11) - will tighten the collar (7) against the pipe (6), securing the notches (12) of such collar against the pipe and will slide such collar on the inner face of the flange (4), achieving the necessary water tightness by means of such sliding of the pipe (6) against the sealing joint (5).

As it has been previously mentioned, the slope of the flange (4) and of the tab (11), supporting the two sloped sections configured at the outer side of the collar (7) enable the tightening of this latter against the pipe (6) fixing the notches (12) and achieving a secure fixing of the coupling and preventing the loosening of the coupling while the nuts (9) are tightened.

Furthermore, and as it has been previously mentioned, this description of the way to carry out the coupling can be applied to any kind of fitting, for instance that represented in figure 2 and under reference (13) which, in this case, is a flange connecting device made of polyethylene.

This fitting is configured from the end (2) forming a groove where the sealing joint (5) is to be housed. Such groove is formed by the cylindrical extension (3) and the outer flange (4) so that, as in the previous case, the relevant pipe (6) will be inserted in the groove where the sealing joint (5) is to be housed. Then, the tightening collar (7) is arranged so that it is tightened by means of the relevant sets of rings and (8) and nuts (9), in the same manner as in the example previously described.

It is not the intention to describe further this invention since any expert on the subject will be able to understand it easily on the basis of the information provided to appreciate the scope of this invention and its advantages and to reproduce it.

It is understood that, provided that the essentials of this invention are not altered, any variations in the materials or in the shape, size and layout of the elements can be introduced.

The terms used in this description as well as their meaning should always be considered as non-limitative.

Claims (8)

1. A pipe coupling for polyethylene pipes comprising a coupling member having an outer socket portion and an inner spigot portion projecting beyond the end of said socket portion and radially spaced apart therefrom to define an annular recess into which a pipe to be coupled is inserted, said recess having a sealing member at the base thereof, said coupling member further comprising an annular elastic collar having a throughbore dimensioned to receive the pipe and means for urging said elastic collar into fluid-tight engagement with the outer circumference of said pipe and for urging the pipe end into sealing engagement with the sealing member.

2. A pipe coupling as claimed in claim 1 wherein the means for urging said elastic collar into fluid-tight engagement with the outer circumference of said pipe and for urging the pipe end into sealing engagement with the sealing member comprises a tightening flange fastenable to a fixed portion on the coupling member by means of a series of threaded rod and nut assemblies, whereby tightening of said nuts on said threaded rods causes translational movement of the tightening collar relative to the coupling member, thereby squeezing said elastic collar and deforming it against the pipe.

3. A pipe coupling as claimed in claim 1 or claim 2 wherein the elastic collar is provided with a series of formations on its inner annular surface.

4. A pipe coupling as claimed in any preceding claim wherein the socket portion is formed with a divergent portion at its mouth and wherein the elastic collar has a complementary profile on its outer surface.

5. A pipe coupling as claimed in any one of claims 2 to 4 wherein the inner annular surface of the tightening collar tapers outwardly in the direction towards the coupling member and wherein the elastic collar is formed with a complementary profile on its outer surface.

6. A pipe coupling as claimed in any preceding claim wherein the coupling member forms part of a pipe fitting.

7. A pipe coupling as claimed in claim 6 wherein the pipe fitting is a gate valve.

8. A pipe coupling substantially as described herein with reference to Figure 1 or Figure 2 of the drawings.