GB2197420A

GB2197420A - Pipe repair collar

Info

Publication number: GB2197420A
Application number: GB08726380A
Authority: GB
Inventors: David Edge Bassett; Kenneth William Rickhuss
Original assignee: SAURUS GENERAL ENGINEERS LIMIT
Current assignee: SAURUS GENERAL ENGINEERS LIMIT
Priority date: 1986-11-12
Filing date: 1987-11-11
Publication date: 1988-05-18
Anticipated expiration: 2007-11-11
Also published as: GB8726380D0; GB8626985D0; GB2197420B

Abstract

A pipe repair collar has semi-cylindrical shells (12) bolted together round a fractured pipe or pipe ends (23A, 23B) of different diameter, and split gland rings (22) urging gland packings (18) into rebates, each of which has a first cylindrical portion (30), a frustoconical portion (31), a second cylindrical portion (32), and an annular shoulder (33), whereby the gland packings (18) can take up positions suitable for sealing on pipe portions (23A, 23B) within the range of diameters that can be accommodated, the second cylindrical portion (32) and the annular shoulder (33) in each rebate ensuring that the gland packings are not dislodged into the interior of the collar. <IMAGE>

Description

SPECIFICATION Pipe repair collar This invention relates to a pipe repair collar of the glanded type in which generally semi-cylindrical shells are adapted to be bolted together round a fractured pipe (e.g. a gas main), with longitudinal sealing strips between the shells, and with gland packings, one in a rebate at each end of the collar and urged inwardly by spigot portions of split gland rings, for sealing between the shells and the pipe portions.

Although increasing axial compression of the gland packings between the gland rings and the inner ends of the rebates results in increasing inward radial expansion of the gland packings to effect sealing round pipes of different diameters, the range that can be accommodated is limited so two sizes of glanded pipe repair collars with different nominal diameters are needed to deal with all sizes of gas pipe currently encountered in the United Kingdom. This presents a considerable manufacturing and stocking problem, even though for each size the semi-cylindrical shells are identical and the half gland rings are identical, and even though common sections of longitudinal sealing strip and of gland packing respectively may suffice for both sizes of collar.

The object of the invention is, therefore, to provide a glanded pipe repair collar having a construction enabling one size to cover a range at least equal to the combined ranges of the two sizes currently in use.

According to the present invention, a pipe repair collar of the glanded type initially described has each rebate formed with a first internal cylindrical portion adjacent the end proper of the collar and an internal frustoconical portion extending from the inner end of the first cylindrical portion inwardly to a second internal cylindrical portion terminating at an annular shoulder which is substantially in a plane perpendicular to the axis of the collar, whereby a gland packing which is initially fitted within the first internal cylindrical portion, to be able to accommodate and seal round the largest size of pipe, can be urged by the spigot portion of the respective split gland ring into the internal frustoconical portion, to effect bodily radial inward movement of the gland packing for effecting sealing round a smaller size of pipe down to the smallest size in the range encountered, whereupon the gland packing is positively located by the second internal cylindrical portion and the annular shoulder against dislodging into the interior of the collar.

The spigot portion of each gland ring preferably has an axial profile with an external frus toconicai portion adjacent an annular inner end in a plane substantially perpendicular to the axis and with an outer diameter greater than the inner diameter of the second internal cylindrical portion of the rebate in the collar, whereby the spigot portion cannot enter the second cylindrical portion of the rebate and thus ensures that there will always be an annular portion of the gland packing gripped between the annular end of the spigot portion and the annular shoulder at the inner end of the rebate.

The outsides of the shells preferably have axial profiles whereby the shells are of substantially uniform thickness throughout their length, except at bolting flanges and anchorages, tapping bosses, and around longitudinal sealing strip grooves.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a small scale perspective view of a pipe repair collar in accordance with the invention, applied to pipes of different diameters; Figure 2 is a fragmentary longitudinal section through the collar and pipes of Fig. 1, on a larger scale; Figure 3 is a fragmentary exploded sectional view, on an even larger scale (e.g., actual size), of one rebate of the collar and its gland ring and a gland packing for use therewith; Figure 4 is a small scale inside plan view of either of the shells forming the collar; Figure. 5 is a section taken from the line 5-5 in Fig. 4; Figure 6 is an end view of the shell; Figure 7 is an inside plan view of one of the gland ring halves on the same scale as Figs. 4 to 6;; Figure 8 is an elevation of the gland ring half taken from the left-hand of Fig. 7; and Figures 9 and 10 are elevations of the gland ring half taken respectively from the left-hand and right-hand sides of Fig. 8.

The pipe repair collar 11 shown in Fig. 1 is of the glanded type in which generally semicylindrical shells 12 are secured together by nuts 13 and bolts 14 passing through flanges 15, with longitudinal sealing strips 16 (Figs. 4 and 5) in grooves 17 sealing between the shells, and with gland packings 18, one in a rebate 19 at each end of the collar and urged inwardly by spigot portions 20 of the halves 21 of the split gland rings 22, sealing between the shells 12 and pipe portions 23A, 23B. The gland halves 21 have overlapping ends 24 with holes 25 (Figs. 7 to 10) for bolts 26 extending from anchoring projections 27 on the shells 12, similar bolts extend through middle holes 28 in the gland halves, and nuts 29 on the bolts 26 are used to urge the spigot portions 20 of the gland halves into the rebates 19.

The pipe portions 23A, 23B in Figs. 1 and 2 have different diameters to illustrate the range of diameters that can be accommodated by a pipe repair collar in accordance with the invention. When used to repair a pipe, both portions 23A, 23B would have the same diameter within that range. However, occasion may arise for the collar 11 to be used to join two pipes of different diameters within the range.

In accordance with the invention, each rebate 19 is formed with a first internal cylindrical portion 30 (which has a very slight taper or ''draw'') adjacent the end proper of the collar and an internal frustoconical portion 31 extending from the inner end of the first cylindrical portion 30 to a second internal cylindrical portion 32 terminating at an annular shoulder 33 which is substantially in a plane perpendicular to the axis of the collar, whereby the gland packing 18 which is initially fitted within the first internal cylindrical portion 30 (c.f.Fig. 3 and the right-hand end of Fig. 2), to be able to accommodate and seal round the largest size of pipe 238, can be urged by the spigot portion 20 of the respective split gland ring 22 into the internal frustoconical portion 31, to effect bodily radial inward movement of the gland packing 18 for effecting sealing round a smaller size of pipe down to the smallest size 23A, whereupon the gland packing is positively located by the second internal cylindrical portion 32 and the annular shoulder 33 against dislodging into the interior of the collar.

The spigot portion 20 of each gland ring 22 has an axial profile with an external frustoconical portion 34 adjacent an annular inner end 35 in a plane substantially perpendicular to the axis and with an outer diameter greater than the inner diameter of the second internal cylindrical portion 32 of the rebate 19 in the collar 11, whereby the spigot portion 20 cannot enter the rebate portion 32 and thus ensures that there will always be an annular portion 36 (Fig. 2) of the gland packing 18 gripped between the annular end 35 of the spigot portion 20 and the annular shoulder 33 at the inner end of the rebate 19. The spigot portion 20 has a narrow bevel 37 between the frustoconical portion 34 and the annular end 35, matching the angle of the frustoconical portion 31 in the rebate 19, to provide co-operating stop surfaces for limiting of the inward movement of the spigot portion.

The outsides of the shells 12 have axial profiles whereby the shells are of substantially uniform thickness throughout their length, except at the bolting flanges 15 and anchorages 27, tapping bosses 38, and around the longitudinal sealing strip grooves.

Claims

1. A a pipe repair collar of the glanded type in which generally semi-cylindrical shells are adapted to be bolted together round a fractured pipe with longitudinal sealing strips between the shells, and with gland packings, one in a rebate at each end of the collar and urged inwardly by spigot portions of split gland rings, for sealing between the shells and the pipe portions, wherein each rebate is formed with a first internal cylindrical portion adjacent the end proper of the collar and an internal frustoconical portion extending from the inner end of the first cylindrical portion inwardly to a second internal cylindrical portion terminating at an annular shoulder which is substantially in a plane perpendicular to the axis of the collar, whereby a gland packing which is initially fitted within the first internal cylindrical portion, to be able to accommodate and seal round the largest size of pipe, can be urged by the spigot portion of the respective split gland ring into the internal frustoconical portion, to effect bodily radial inward movement of the gland packing for effecting sealing round a smaller size of pipe down to the smallest size in the range encountered, whereupon the gland packing is positively located by the second internal cylindrical portion and the annular shoulder against dislodging into the interior of the collar.

2. A pipe repair collar as in Claim 1, wherein the spigot portion of each gland ring has an axial profile with an external frustoconical portion adjacent an annular inner end in a plane substantially perpendicular to the axis and with an outer diameter greater than the inner diameter of the second internal cylindrical portion of the rebate in the collar, whereby the spigot portion cannot enter the second cylindrical portion of the rebate and thus ensures that there will always be an annular portion of the gland packing gripped between the annular end of the spigot portion and the annular shoulder of the inner end of the rebate.

3. A pipe repair collar as in Claim 2, wherein each spigot portion has a narrow bevel between its frustoconical portion and its annular end, matching the frustoconical portions in the rebate, to provide co-operating stop surfaces for limiting of the inward movement of the spigot portion.

4. A pipe repair collar as in any one of Claims 1 to 3, wherein the outsides of the shells have axial profiles whereby the shells are of substantially uniform thickness throughout their length, except at bolting flanges and anchorages, tapping bosses, and around longitudinal sealing strip grooves.

5. A pipe repair collar substantially as herin before described with reference to the accompanying drawings.