GB2184805A - Cover for pipe connection or valve - Google Patents

Abstract

A cover for a flanged pipe joint 31 or a valve positioned in a pipe comprises at least two plastics parts releasably connectable to define an inner annular chamber 30 to accommodate the flange or valve. The parts may be of glass fibre reinforced polyester and may be lined with glass fibre or phenolic urethane foam insulation. <IMAGE>

Description

SPECIFICATION Cover for pipe connection or valve This invention relates to a cover for a pipe connection or for a valve located in a pipeline.

Pipelines which are used for conveying heated or temperature-controlled fluids and which are exposed to the external environment, e.g. oil refinery or factory central heating pipes, are invariably provided with external lagging to minimize heat loss. The lagging in turn usually has a waterproof outer layer to protect it against rain, snow etc. since when soaked through the insulating properties thereof are considerably diminished. Gaps in the insulating lagging occur at connections between pipe sections where outwardly projecting flanges at the ends of adjacent pipe sections are secured to one another. Similarly, gaps occur where valves and similar control devices are inserted into the pipeline. Obviously considerable heat loss will take place at these gaps.Indeed, it is calculated that the heat loss at a flange connection of a standard hot water pipeline is equivalent to the usual heat loss over 1/2m of pipe. Moreover, unless special measures are taken to cover the ends of the lagging, it will be exposed and thus susceptible to wetting.

In view of the foregoing, flange covers have been provided in the form of approximately cylindrical sleeves of thin aluminium sheeting with some form of internal insulation. These covers are not particularly satisfactory. They are liable to be stolen because the aluminium has a reasonable scrap value. Also the edges of the aluminium sheeting must be rivetted together to provide a weatherproof seal and this means that the cover cannot readily be removed if access to the pipe connection is required. Furthermore, some form of connection, e.g. by means of sealing tape, must be provided between the aluminium sleeve and the adjacent lagging and this tends to deteriorate and let in water after a short period.

The average useful life of such flange covers is, in fact, only about six months.

It is an object of the present invention to provide an improved weatherproof cover for a flange connection, or for a valve or similar control device, which does not have the above-mentioned disadvantages.

Pursuant hereto the invention provides a weatherproof cover for a pipe connection or for a valve or similar control device located in a pipeline, said cover comprising at least two curved parts of moulded plastics which are releasably connectable to form an annular radially inwardly open channel.

Being made of plastics, such a cover is less expensive to produce than the previously known aluminium cover and as it is of little value it is unlikely to be stolen.

In a preferred embodiment, the cover consists of two symmetrical, substantially semicircular parts which are located relative to each other by mutually inter-engaging lugs and recesses and are releasably secured to each other by captive bolts.

In practice there should be no gap and no radial shoulder between the cover and the adjacent conventional lagging to minimise seepage of water therebetween. Also, the width of the channekl inside the cover should be sufficient to permit the bolts securing the pipe flanges to be removed and replaced longitudinally of the pipeline without interference by adjacent lagging when the cover is released and lifted away from the pipeline.

Advantageously the plastics used for moulding the cover part is glass fibre reinforced polyester resin and an appropriate thickness of insulation in the form of glass fibre or plendic urethane foam is subsequently used to line the respective parts of the cover.

In radial section, the channel is preferably formed by a base portion, respective side walls, which are spaced apart by a distance greater that the width of the base portion, and respective curved corner regions extending between the base portion and each side wall. The corner regions are advantageously depressed inwardly (i.e. concave) relative to the channel and each provided with an outwardly projecting ridge a short spacing from its junction with the respective side wall. The aforesaid concave shape of the corner regions and the ridges which are provided facilitate run off of water from either side of the cover and thereby minimise the possibility of the pipe insulation becom soaked. The ridges are also important in providing, at each side of the cover, an abutment for sealing tape or other sealing means connecting the outer layer of adjacent lagging to the cover.

The side walls of the cover channel are conveniently substantially perpendicular to the base portion thereof.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a fragmentary side view illustrating a preferred embodiment of the cover of the invention in place around a pipe flange connection and secured to adjacent pipe lagging; Figure 2 is a cross-section of the same cover to a slightly larger scale along the line 2-2 of Fig. 1, with the pipe section shown in dot-dash line without any insulation; and Figure 3 is a cross-section of the same cover along the line 3-3 in Fig. 2, the two parts thereof being separated from each other.

As illustrated in the drawings, a preferred embodiment of the cover of the invention, which in this case is designed for a pipe connection and hence is referred to as "a flange cover", comprises two substantially symmetrical, semicircular parts 10, 20 of moulded plas tics. The plastics is preferably glass fibre reinforced polyester resin which is heat cured in the mould and the same mould can, of course, be used for both parts. The parts 10, 20 are so shaped that when they are joined together they provide a radially inwardly open channel 30 in which, in use, the pipe flange connection 31 will be accommodated, as indicated in Figs. 1 and 2.

The radial cross-section or profile of the channel 30 is of special shape, as shown in Fig. 2. It consists of a base portion 11 and respective side walls 12, 13, which are approximately perpendicular to the base portion 11 and are spaced apart by a distance greater than the width of the base portion 11. Extending between the base portion 11 and each side wall 12, 13 is a respective curved corner region 14, 15, which is inwardly depressed relative to the channel. Each corner region 14, 15 is provided with an outwardly projecting ridge 16, 17 a short spacing from its junction with the respective side wall 12, 13. Thus, when the two parts 10, 20 are joined an annular ridge is formed at each side of the cover.

For accurate location relative to each other, the two parts 10, 20 are provided with mutually engaging lugs and recesses. As indicated in Figs. 2 and 3, each part 10, 12 is provided with two diametrically opposed lugs 18 and two diametrically opposed recesses 19 of corresponding shape on their mutually facing edges where the corner regions 14, 15 of the channel profiles merge into the side walls 12, 13.

The base portion 11 of each cover part 10, 20 is provided at each end with a tapering external groove 21 culminating in a cross-wall 22, 23. The cross wall 22 in one groove 21 is provided with an aperture 26 and a suspending larger diameter depression 24 in its surface facing the other part for reception of a washer (not shown), whilst the cross-wall 22, in the other groove 21 is considerably thicker and is provided with a threaded bore 25. The two cover parts 10, 20, which are identical in configuration, are releasably connectable by captive bolts 27 projecting through the apertures of one part engaging into the threaded bore 25 of the other part.

The channels 30 are lined with insulation, such as glass fibre or phenolic urethane foam, but this is not shown in the drawings.

In use, the two parts 10, 20 are connected together by bolts 27 so as to encircle and provide a weatherproof cover around end flanges 31 of pipe sections 32, 33, which are connected by bolts 34, as indicated in Fig. 1.

The pipe sections 32, 33 are provided with external lagging 35, which is of standard diameter and has a waterproof outer layer. When this lagging 35 is applied, it is terminated a sufficient distance from the respective flange 31 to allow for fitting of the cover with negligible space therebetween. The length of the side walls 12, 13 is chosen to equal the radial thickness of the lagging 35 so that the waterproof surface of the lagging 35 at each side of the cover is level with the junction between the respective side walls 12, 13 and corner regions 14, 15. Sealing tape 36 is then wound around the joint to connect the cover to the lagging 35, one edge of the tape 36 abutting the respective ridge 16, 17.

The curvature of the corner regions 14, 15 and the presence of the ridges 16, 17 means that rainwater impinging on the cover from any direction is caused to drain off rapidly so that it does not soak into the underlying insulation and render it useless.

The cover can readily be removed when access to the pipe connection is required by firstly removing the tape 36, then unfastening the bolts 27 and separating the two parts 10, 20. The width of the channel 30 is chosen so that there is sufficient room between the edges of the lagging 35, when the cover is removed, for removal of the bolts 34 from the flange connection 31. As the cover is not damaged by removal, it can be replaced or reused at a later time.

It should be appreciated that the invention is not limited to the precise details of the foregoing embodiment, which is merely given as an example. A similar cover, somewhat different in dimensions may be provided for a valve or other control device located in a pipeline.

Also the cover could conceivably be made of more than two parts and these may be secured together in some other way than that described. Other variations are possible.

Claims (8)

1. A weatherproof cover for a pipe connection or for a valve or similar control device located in a pipeline, said cover comprising at least two curved parts of moulded plastics which are releasably connectable to form an annular radially inwardly open channel.

2. A cover as claimed in claim 1 and consisting of two symmetrical, substantially semicircular parts which are located relative to each other by mutually inter-engaging lugs and recesses and are releasably secured to each other by captive bolts.

3. A cover as claimed in claim 1 or 2 wherein the plastics used for moulding the cover parts is glass fibre reinforced polyester resin.

4. A cover as claimed in claim 1, 2 or 3 wherein the inwardly open channel is lined by insulation material in the form of glass fibre or phenolic urethane foam.

5. A cover as claimed in any preceding claim wherein the channel, in radial section, is formed by a base portion, respective side walls, which are spaced apart by a distance greater that the width of the base portion, and respective curved corner regions extend ing between the base portion and each side wall.

6. A cover as claimed in claim 5 wherein the corner regions are depressed inwardly (i.e.

concave) relative to the channel and each provided with an outwardly projecting ridge a short spacing from its junction with the respective side wall.

7. A cover as claimed in claim 5 or 6 wherein the side walls of the channel are substantially perpendicular to the base portion thereof.

8. A weatherproof cover for a pipe connection or for a valve or similar control device located in a pipeline substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.