GB2177175A - Pipe sealing clamp - Google Patents

Abstract

Retaining ring 10, preferably consisting of two parts 50 clamped together by bolts 54, is configured to provide a recess accommodating a sealing ring 12 around spigot end 22 of pipe 16 which projects into socket end 24 of pipe 18. Anchor ring 8 preferably also consists of two parts 32 clamped together by bolts 36 around the socket end 24 and has therethrough tension bolts 14 which enable the retaining ring 10 to be drawn towards the anchor ring 8 thereby to compress the sealing ring 12 against end face 28 of the socket 24 and to deform the ring 12 radially inwards to seal with the spigot end 22, circumferential flange 56 of the retaining ring 10 projecting beyond the centre plane of the sealing ring 12 to ensure this radial inward deformation. It is essential to the invention that the radial cross-section of the sealing ring 12 should differ from that of the recess provided therefor in the retaining ring 10. <IMAGE>

Description

SPECIFICATION Pipe sealing clamp This invention concerns pipe sealing clamps of the kind employed upon the interfitting ends of pipes such as are used, for example, as gas mains or water mains, and where the end of one of the pipes is enlarged to form a socket into which the end of the other of the pipes projects as a spigot, usually of substantially constant diameter. Such pipes may, for instance, be of metal or asbestos cement.

The invention is more particularly concerned with pipe sealing clamps of the kind aforesaid which comprise a multi-part anchor ring which can be clamped around the socketed pipe end to abut against the socket, a multi-part retaining ring for assembly around the spigot pipe end, a deformable sealing ring for location between the retaining ring and the confronting end face of the socketed pipe end, and tension belts for drawing the anchor ring and the retaining ring relatively towards one another to effect deformation of the sealing ring to cause the latter to create a seal between the interengaged pipe ends.

In the known constructions of sealing clamps the gap between the face of the pipe socket and the pipe spigot is usually bridged by a sealing ring made from an elastomeric material such as rubber. The sealing rings are usually angular in cross-section and/or the face of the retaining ring presented to the sealing ring is flat and inclined to advance the sealing ring in the direction between the pipe spigot and pipe socket when the tension bolts are tightened. Thus, the sealing ring and the retaining ring are of complementary radial cross-section.

In general, these known sealing clamps are not too well liked in environments where they are subject to vibration, e.g. under roadways, or where the pipes being sealed therewithdo not have a smooth external surface, e.g. are pitted, deeply scored or the like, since they can readily develop leaks and thus require resealing and/or replacement.

An object of the present invention is to provide a construction of sealing clamp which is less susceptible to these disadvantages, which can be used with pipes produced to a wide tolerance range, without there being any significant risk of an unsatisfactory seal being achieved, and which can be constructed so as to be usable with a relatively wide range of pipe sizes.

With this object in view, the present invention provides a pipe sealing clamp of the kind employed on the interfitting ends of pipes where the end of one of the pipes is enlarged to form a socket into which the end of the other of the pipes projects as a spigot, and comprising a multi-part anchor ring which can be clamped around the socketed pipe end to abut against the socket, a multi-part retaining ring for assembly around the spigot pipe end, a deformable sealing ring for location between the retaining ring and the confronting end face of the socketed pipe end, and tension bolts for drawing the anchor ring and the retaining ring relatively towards one another to effect deformation of the sealing ring to cause the latter to create a seal between the interengaged pipe ends, characterised in that the retaining ring is, in radial cross-section, of angular configuration providing an externally circumferential flange substantially concentric with the pipes and defining a recess into which the sealing ring locates, the flange projecting over the sealing ring by at least 50% of the extent thereof considered in the axial direction of the pipes, and the sealing ring being of cross-section differing from that of the recess so that tightening of the tension bolts results primarily in urging of the sealing ring against said confronting end face and radial inward deformation of the sealing ring to seal with the external surface of the spigot pipe end.

The retaining ring is preferably of a crosssection providing an annular face of a frustoconical configuration inclined towards the socketed pipe end in its outward direction, with the flange being provided around and contiguous therewith.

Openings in both rings for the tension bolts are advantageously such as to enable the tension bolts to adopt dispositions not parallel to the axes of the pipes. This enables the clamp to be employed not only in conjunction with pipes of wide manufacturing tolerance but also in conjunction with a wide range of pipe sizes.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an elevation illustrating a preferred embodiment of the pipe clamp of the invention assembled and installed in position ready for sealing together the interfitting ends of two pipes; Figure 2 is a part-sectional side view taken from the left hand side of Fig. 1 and showing primarily the details of the retaining ring of the pipe clamp; Figure 3 is a part-sectional side view taken from the right hand side of Fig. 1 and showing primarily the details of the anchor ring of the pipe clamp; Figure 4 is a detached fragmentary radial section through part of the pipe and clamp assembly of Figs. 1 to 3, illustrating the relative dispositions of various of the components prior to tightening up the tension bolts of the pipe clamp;; Figure 5 is a view comparable with Fig. 4, but showing the conditions of the parts when the tension bolts of the pipe clamp have been partly tightened up and the interfitting ends of the two pipes are sealed together; and Figure 6 is a view comparable with Figs. 4 and 5, but showing the parts when the tension bolts have been fully tightened.

The preferred embodiment of the pipe clamp illustrated in the drawings comprises a multi-part anchor ring indicated by the reference numeral 8, a multi-part retaining ring indicated generally by the reference numeral 10, a deformable sealing ring indicated generally by the reference numeral 12, and tension bolts 14 the purpose of which, as will be described later, is to draw the anchor ring 8 and retaining ring 10 relatively towards one another. As will be primarily evident from Fig. 1, the purpose of the pipe clamp of the invention is to create a fluid-tight seal between the interfitting ends of two pipe lengths 16, 18 of which the pipe length 18 has an enlarged end 20 which constitutes a socket and the other pipe length 16 has a substantially constant diameter end 22 which fits spigot-wise into the socket.The enlarged end 20 is configured to provide an intermediate substantially frusto-conical portion 24 and a larger frusto-conical terminal portion 26 which presents a substantially planar end face 28 (see figures 4, 5 and 6) over the spigot 22 which projects therein.

The anchor ring 8 (see particularly Figs. 1 and 3) comprises two near semi-circular halves 30, which are substantially identical but as shown are arranged relative to one another to form a ring. Each half 30 comprises an arcuate element 32 having, at each end, an out-turned lug 34 for reception of clamping bolts 36, and thickened integral bosses 38 are provided at spacings thereon so that when the two halves 30 are clamped together as shown in Figs. 1 and 3, these bosses 38 are effectively disposed as at the four corners of a rectangle or a square, according to the size of the pipes being sealed, it being understood that the clamp can be used in conjunction with a range of sizes of pipe. Holes 40 through the bosses 38 are square in section for co-operation with complementary formations on the stems of the tension bolts 14 to prevent rotation of the latter.Faces 42 of the bosses 38 remote from the lugs 34 are substantially planar, whilst the opposite faces thereof each include a planar portion 44 and an angled portion 46 which enables the respective bolt 14 to be disposed at an angle to the axis of the pipes, as shown in Fig. 1.

The extent of each ring half 30 is less than a semi-circle, and the dimensions thereof are as chosen in relation to the size of the pipe 18 that when the anchor ring 8 is arranged therearound there will be a gap between the confronting lugs 34 when the bolts 36 have been tightened to cause the bosses 38 to grip against the external surface of the pipe end 20. The bosses 38, of course, are effective to provide point contact between the anchor ring 8 and the socketed pipe end 20, and this ensures that the clamp can be used with a range of sizes of pipe, and also that the ring 8 can be tightly secured in position regardless of wide manufacturing tolerances which are permitted in relation to manufacture of the pipes.

The retaining ring 10 comprises two identical substantially semi-circular halves 50 which have respective lugs 52 at their ends to permit them to be clamped together in circular configuration around the spigot end 22 of the pipe 16 by bolts 54. In contrast with the anchor ring 34 where the confronting lugs 34 of the two ring parts 30 are spaced apart when the parts of the ring 8 are clamped in place, the confronting lugs 52 abut one another. As will be evident from Fgis. 4, 5 and 6, the ring 10 is configured to provide, at its face opposite to the lus 52, a frusto-conical portion 55 around which is a circumferential flange 56, this configuration defining an annular recess for accommodating the deformable sealing ring 12 which, ring 12, as will be seen from Fig.

4, is substantially circular in radial cross-section in its relaxed condition. This ring is formed, of course, of a length of circular-sectioned material appropriately introduced into the recess and accurately dimensioned for its free ends then to abut. The extent of the flange 56 is such, relative to the diameter of the ring 12, that it projects beyond the centre plane of the ring 12.

Integral lobes 60 are provided on the rings parts 50 in locations corresponding to the bosses 38 on the ring 8, and these lobes 60 have similar holes 62 and are also provided with respective planar and angled surfaces 64, 66.

The manner of use of the pipe clamp will readily be understood from the foregoing description. Assuming the two pipe lengths 16, 18 to be in-situ in the ground and to have developed a leak at the joint therebetween, firstly the anchor ring 8 is clamped in place as described above and then the retaining ring 10 is assembled in place and its two parts are bolted together. The sealing ring 12 is then put in place, whereupon the tension bolts 14 are put in position and tightened up. Figs. 4, 5 and 6 show the retaining ring 10 being drawn towards the anchor ring 8 and towards the planar end face 28 of the socket 20. As will be seen, the compressive effect of the retaining ring 10 on the sealing ring 12 is to press the ring 12 firmly against the end face 28 and also to deform the ring 12 radially inwards to seal around the spigot end of the pipe 16. This sealing is effective, regardless of any non-circularity or other shape deficiency or defect in either of the pipes.

The primary advantages of the clamp of the invention lie in the facts that it can be employed with a wide range of sizes of pipe, and that it compensates for the very wide tolerance ranges which are commonplace in the manufacture of such pipes. Moreover, it will provide very efficient seals on pipes of which the surfaces are pitted or have other defects which normally make sealing very difficult.

The invention is not confined to the precise details of the foregoing example and variations may be made thereto. Thus, for instance, it is not essential that the retaining ring 10 should be configured to provide the frusto-conical portion 55, which may be generally planar.

Moreover, the sealing ring 12 may be of any suitable radial cross-section, such as oval or elliptical.

The method of clamping the parts of the retaining ring 10 together may differ from what is shown as also may the method of joining the parts of the anchor ring 8. It is not essential to the invention that there should be a gap between the lugs 34 of the anchor ring 8 and the arrangement could be such that these lugs abut or such that outer arms of each ring part could overlap one another.

The arrangement permitting angular dispositions of the tension bolts 14 between the retaining ring 10 and the anchor ring 8 is not essential to the invention. The arrangement could, if desired, be such that the pitch circle diameter of the bolt bosses 38 on the anchor ring 8 could be larger and the bolts 14 could be inclined towards the pipes.

If desired, the bolt bosses on the anchor ring 8 and on the lobes on the retaining ring could be slotted to enable the bolts 14 to be parallel and as close as possible to the line of the pipes.

The number of parts each in the retaining ring 10 and in the anchor ring 8 and the number of tension bolts 14 joining them may vary.

For instance there could be three ring parts with one bolt boss or lobe on each part. Of course, the number of parts and bolt holes must be the same for the retaining ring 8 and the anchor ring 10.

It is essential for the cross-sectional forms of the recess in the retaining ring 10 and of the sealing member 12 to be different from on another, although not necessarily as described. The invention depends on an effective seal being obtained before the sealing member 12 has been deformed to occupy fully but not protrude from the space between the retaining ring recess, the pipe socket face 28 and the pipe spigot 22. Furthermore the sealing member 12 must not readily enter the gap between the end of the retaining ring recess and the pipe socket face 28 and the gap between the opposite end of the retaining ring recess and the pipe spigot 22.

Claims (7)

1. A pipe sealing clamp of the kind employed on the interfitting ends of pipes where the end of one of the pipes is enlarged to form a socket into which the end of the outer of the pipes projects as a spigot, and comprising a multi-part anchor ring which can be clamped around the socketed pipe end to abut against the socket, a multi-part retaining ring for assembly around the spigot pipe end, a deformable sealing ring for location between the retaining ring and the confronting end face of the socketed pipe end, and tension bolts for drawing the anchor ring and the retaining ring relatively towards one another to effect deformation of the sealing ring to cause the latter to create a seal between the interengaged pipe ends, characterised in that the retaining ring is, in radial cross-section, of angular configuration providing an externally circumferential flange substantially concentric with the pipes and defining a recess into which the sealing ring locates, the flange projecting over the sealing ring by at least 50% of the extent thereof considered in the axial direction of the pipes, and the sealing ring being of cross-section differing from that of the recess, so that tightening of the tension bolts results primarily in urging of the sealing ring against said confronting end face and radial inward deformation of the sealing ring to seal with the external surface of the spigot pipe end.

2. A pipe clamp as claimed in claim 1 wherein the retaining ring is of a cross-section providing an annular face of a frusto-conical configuration inclined towards the socketed pipe end in its outward direction, the flange being provided around and contiguous therewith.

3. A pipe clamp as claimed in claim 1 or 2 wherein openings in the anchor ring and in the retaining ring for the tension bolts are so disposed as to enable the tension bolts to adopt dispositions not parallel to the axes of the pipes.

4. A pipe clamp as claimed in claim 1, 2 or 3 wherein the sealing ring, in its relaxed condition, is circular in radial section.

5. A pipe clamp as claimed in any preceding claim wherein the anchor ring comprises elements which, when clamped around a pipe socket, are spaced apart from one another.

6. A pipe clamp as claimed in claim 5 wherein the anchor ring provides a boss for each tension bolt, which bosses provide point contact between the anchor ring and the socketed pipe end.

7. A pipe clamp substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.