GB2161233A - Improvements in or relating to pipe joints - Google Patents

Abstract

A pipe joint comprising a socket end 2 of one pipe 1 adapted to receive a spigot end 14 of a second pipe 15, in which the socket end is provided with an annular extension member 8 welded to the end thereof and incorporating a peripheral groove 9 extending around the inner surface thereof; one or more protrusions 16 located in ring-like disposition around the outer periphery of the spigot; and a resilient locking ring 12 located within the groove in the extension member 8 of the socket; the arrangement being such that on insertion of the spigot 14 through the extension member 8 of the socket 2, the annular protrusion or protrusions 16 thereon force the resilient locking ring 12 radially outwardly into the groove 9 in the extension member 8 until the protrusion or protrusions have passed the ring, whereafter the locking ring springs into contact with the spigot behind the protrusion or protrusions thereby locking the spigot in the socket. In particular flexible pipelines with non-locking pipe joints can be readily modified to locking format by the welded addition of the extension member. <IMAGE>

Description

SPECIFICATION Improvements in or relating to pipe joints This invention relates to pipe joints. More particularly the invention relates to pipe joints of the selflocking or self-anchoring type between a spigot of one pipe and a socket of another pipe.

One form of self-anchoring type joint previously proposed for connection between the spigot end of one pipe and the socket end of another pipe includes the provision of a weld bead around the periphery of the spigot adjacent the end thereof and a split resilient circular locking ring located within a relatively deep groove around the inner periphery of the socket such as to enable the bead to pass radially beneath the circlip on entry of the spigot into the socket.

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 pipework such as elbows and 'T' junction end members.

It is an object of the present invention to provide a joint of the self-anchoring type of a convenient and practical form.

In accordance with this invention there is provided a pipe joint comprising a socket end of one pipe adapted to receive a spigot end of a second pipe, in which the socket end is provided with annular extension member welded to the end thereof and incorporating a peripheral groove extending around the inner surface thereof; one or more protrusions located in a ring around the outer periphery of the spigot; and a resilient anchoring ring located within the groove in the extension member of the socket; the arrangement being such that on insertion of the spigot through the extension member of the socket, the annular protrusion or protrusions thereon force the resilient locking ring radially outwardly into the groove in the extension member until the protrusion or protrusions have passed the ring, whereafter the locking ring springs into contact with the spigot behind the protrusion or protrusions thereby locking the spigot in the socket.

The protrusion may be a continuous bead of weld material formed around the outer surface of the spigot. The locking ring may be a resilient split circlip.

The groove may have a tapered side wall nearest to the open mouth of the extension member, and the locking ring may have a corresponding tapered surface on its radially outer periphery whereby any attempt to move the spigot out of the socket will cause the locking ring to be forced by the protrusion from the spigot into engagement between the mating inclined surfaces of the locking ring and the groove in the extension member of the socket so that the locking ring will be forced more tightly about the spigot and its locking action increased.

Many pipeline systems, such as flexible pipelines for transmitting water, only require the provision of a locking joint at particular locations where, for example, the pipeline is potentially or actually subject to tensile forces along the line thereof. An advantage of the present invention is that non-locking pipes, having spigot and socket joints with sealing members of a standard form for such pipelines, can be readily modified by the addition by welding of an extension member for locking purposes. By this means there is no requirement for special, expensively produced pipes incorporating special locking sockets to be provided and it is only required that a stock of appropriate shaped extension members and locking rings be retained for use to form a lockable joint pipe as required in the pipeline.

Thus, by means of the invention in this particular example of its application, pipe production costs are reduced as are site assembly costs and time. It is to be noted that the invention obviates the use of any bolting mechanism, which again is of considerable economic benefit with regard to expenditure and time.

In order that the invention may be more readily understood two embodiments thereof will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a partial section in side elevation of one embodiment of an anchorable joint according to the invention; and Figure 2 is a partial section in side elevation of another embodiment of an anchorable joint according to the invention.

Referring to Figure 1, it is to be observed that a ductile iron pipe 1 has a socket end 2 of normal configuration for a non-locked connection. Thus, the socket carries within a groove 3 behind radially inwardly extending flange 4 a resilient sealing member 5 held in place within the socket by means of a part spherical section internal protrusion 6. Welded by means of a substantial iron weld bead 7 to the end face of the flange 4 of the socket 2 is a ductile iron annular extension member 8 incorporating a groove 9 having, towards its open mouth 10, an inclined surface 11.

Disposed within the groove 9 is a resilient split locking circlip 12 of spring steel. The circlip has a face 13 of matching angle to the inclined face 11 of the groove, so that it is capable of sliding along such inclined face of the groove.

Located within the socket 2 and the extension member 8 is the spigot 14 of a further pipe 15.

The spigot is in sealing engagement with the sealing member 5 so that the contents of the pipe are sealed against the atmosphere.

In addition, the spigot is locked within the socket and extension member by engagement of an annular peripheral weld bead 16 produced therearound the bead 16 engaging upon an edge 17 of the circlip.

The pipes of which the socket and spigot are part, are standard pipes for use in a flexible nonanchored pipeline system. In practice where, in the construction of such a pipeline, it is required that an anchored joint be provided, then a pipe is provided in which the extension member 8 is welded to the end of the socket 2 of the pipe 1. The bead 16 of weld material is then applied around the pe riphery of the associated spigot 14 of the juxtaposed pipe 15, and the spigot 14 inserted into the extension member with the circlip disposed therein. Upon insertion the weld bead 16 bears against a tapered surface 18 of the circlip 12 forcing the circlip 12 along and outwardly into the groove 9 in the extension member 18 until the weld bead 16 is able to pass under the circlip 12.

As soon as it is passed under the circlip 12 the resilient circlip 12 immediately snaps behind the bead 16 of weld material into engagement with the pipe 15. The joint is now anchored or locked. Any attempt to remove the spigot 14 outwardly from the extended socket 2 and 8 will cause the bead 16 of weld material to bear against the corner 17 of the circlip forcing the inclined surface 13 of that circlip to engage with the mating inclined surface 11 of the groove in the extension member, thereby merely serving to increase the engagement of the circlip 12 upon the pipe 15 behind the bead 16 of weld material and thus increase the locking action.

The arrangement illustrated in Figure 2 is similar to that of Figure 1 except that in this case the extension member 19 is so shaped as to provide a radially outer portion 20 which overlays radially a radial recess 21 at the outer edge in the normal socket end of the pipe. The extension member can be an interference fit in the recess 21 of the end of the socket, and indeed can be arranged to be thermalshrink fit in the recess 21. After fitting of the portion 20 of the extension member 20 in the recess 21, welding is then carried out and a substantial weld bead 22 is laid down. The operation of the embodiment of the invention illustrated in Figure 2 is the same as that of the embodiment illustrated in Figure 1.

For withdrawal of the spigot from the socket in either of the embodiments illustrated, a plurality of wedges can be inserted into the gap between the mouth of the socket extension member 8 and the spigot 14 around the periphery so as to force the circlip 12 radially outwardly within the groove 9 so as to be disengaged from the weld bead 16 whereafter the spigot 14 may be withdrawn from the socket 2.

The joint of the present invention can be formed with the pipes, socket extension and weld beads of iron, so that environmental corrosion problems in use are very small or non-existent.

A significant advantage of the present invention is that the socket extension member can have various internal and external dimensions and configurations, both axially and radially to accommodate a wide variety of special requirements for lockable joints concerning for example joint deflection, freedom of axial movement and pressure requirements, whilst still using the same basic pipe.

Compared to earlier proposals to bolt an extension end piece on to a pipe, the invention has important advantages in that assembly is very simple, effective and fast, and that the normal requirement of bolted arrangements for all relevant pipes which might be associated with an extension end piece to have at the socket ends thereof an outer peripheral flange in each case for bolt support purposes, which has amongst other things, a particularly unfortunate stiffening effect, reducing considerably the flexibility of the joint, is avoided.

By means of the invention we have provided a useful convenient and economic manner of providing a self-anchoring joint for pipes.

Claims (8)

1. A pipe joint comprising a socket end of one pipe adapted to receive a spigot end of a second pipe, in which the socket end is provided with an annular extension member welded to the end thereof and incorporating a peripheral groove extending around the inner surface thereof; one or more protrusions located in ring-like disposition around the outer periphery of the spigot; and a resilient locking ring located within the groove in the extension member of the socket; the arrangement being such that on insertion of the spigot through the extension member of the socket, the annular protrusion or protrusions thereon force the resilient locking ring radially outwardly into the groove in the extension member until the protrusion or protrusions have passed the ring, whereafter the locking ring springs into contact with the spigot behind the protrusion or protrusions thereby locking the spigot in the socket.

2. A pipe joint according to Claim 1 wherein the protrusion is a continuous bead of weld material formed around the outer surface of the spigot.

3. A pipe joint according to Claim 1 or 2 wherein the locking ring is a resilient split circlip.

4. A pipe joint according to any one of the preceding claims wherein the peripheral groove has a side wall nearest to the open mouth of the extension member inclined in a direction radially inwardly and towards the open mouth of the extension member, and, the locking ring has a cor responding inclined surface on its radially outer periphery capable of mating connecting with the inclined wall of the groove, whereby the locking ring is urged radially inwardly if it is subjected to an axial force towards the open mouth of the extension member.

5. A pipe joint according to any one of the preceding claims wherein the extension member is welded to an axially end face of the socket.

6. A pipe joint according to any one of Claims to 4 wherein the extension member radially overlies at least part of the socket and is welded to a radially outer wall of the socket.

7. A pipe joint substantially as shown in and a hereinbefore described with reference to the accompanying drawings.

8. Pipework incorporating a pipe joint according to any one of the preceding claims.