GB2187815A

GB2187815A - Pipe freezing apparatus

Info

Publication number: GB2187815A
Application number: GB08606272A
Authority: GB
Inventors: Thomas David Freimuth
Original assignee: WAVECARE Ltd
Current assignee: WAVECARE Ltd
Priority date: 1986-03-13
Filing date: 1986-03-13
Publication date: 1987-09-16
Anticipated expiration: 2006-03-13
Also published as: GB8606272D0; GB2187815B

Abstract

A block 14 of foamed rubber/plastics is held between two layers 12, 13 of liquid proof material and has an exposed section defined by an aperture 15 in layer 13. This assembly forms a jacket 10 which is wrapped around a pipe to be frozen such that the exposed part of block 14 is in contact with the pipe, the jacket 10 being secured to the pipe inter alia by means of the cords 16. Refrigerant e.g. chlorodifluoromethane is then supplied to the block 14 via a bushing, whereby an ice plug can be created in the pipe. <IMAGE>

Description

SPECIFICATION Pipe freezing apparatus This invention relates to pipe freezing apparatus.

In order to prevent the need for mains water supply to be shut off while repairs or extensions are carried out to existing pipework, systems have been developed for freezing the pipework at isolated locations to form ice plugs which act as temporary stop valves. Such systems presently aimed at the amateur market cater only for relatively small diameter (15 to 28 mm) pipes, and although systems exist which enable larger diameter pipes to be frozen these are usually expensive and/or wasteful of refrigerant. For example, in one such system a rigid clamp is secured to the pipework and forms a hollow cavity adjacent to the pipe into which a liquid refrigerant is injected, while in another such system a flexible insulated jacket is fixed around the pipework and liquid carbon dioxide is injected continuously into the space between the jacket and the pipe to form solid dry ice in that space.

It is an object of the present invention to provide pipe freezing apparatus suitable for both the professional and the amateur market that enables relatively large diameter pipes to be frozen at modest cost.

According to the present invention, pipe freezing apparatus comprises a flexible jacket for wrapping around a pipe to be frozen, the jacket being composed of a substantially continuous layer of liquid proof material which forms an outer cover of the jacket when the latter is wrapped around said pipe in use, a layer of absorbent material attached to the cover and exposed to a surface of the jacket which confronts said pipe in use, passage means whereby a refrigerant medium can be introduced through the jacket from the exterior thereof and into the absorbent material, and securing means whereby the jacket can be secured to said pipe in use.

Preferably, the jacket also includes a second layer of liquid proof material, the layer of absorbent material is disposed between said layers of liquid proof material, and said second layer is apertured to expose the absorbent material at said confronting surface of the jacket.

The passage means desirably comprises a bushing extending through the outer cover and the layer of absorbent material whereby the refrigerant medium can be introduced into a space formed between the jacket and said pipe in use and thence into the absorbent material, the bushing advantageously having a constriction incorporated therein.

Preferably, the refrigerant medium employed is chlorodifluoromethane.

Conveniently, the securing means includes means for clamping each end of the jacket to said pipe, preferably in the form of tie cords. Alternatively or additionally, the securing means can include fastening means on or adjacent to side edges of the jacket which extend along said pipe in use, preferably in the form of strips of hook and eye fabric.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a flexible jacket which forms part of pipe freezing apparatus according to the present invention; and Figure 2 is a sectional view showing the pipe freezing apparatus in use.

The illustrated pipe freezing apparatus is composed principally of a flexible jacket 10 which is wrapped around a pipe 11 to be frozen in the manner depicted in Fig. 2. The jacket 10 includes a substantially continuous layer 12 of liquid proof material which forms an outer cover, and this material is turned over to form another layer 13 which confronts the pipe 11 in use. The layerxs 12 and 13 together form opposed pockets into which is inserted a block 14 of absorbent material, such as foamed rubber or foamed plastics. In a preferred embodiment, the block 14 is made of polyurethane foam. The turned-over parts of the liquid proof material are spaced apart so that a rectangular aperture 15 is effectively defined in the layer 13, whereby the block 14 is exposed to the pipe 11 in use.

At each end of the jacket 10, the liquid proof material is seamed so as to form a channel through which a respective tie cord 16 extends, each cord 16 passing through the cover 12 by means of respective eyes 17. These tie cords enable the ends of the jacket 10 to be clamped to the pipe 11 and thereby form an essentially liquid proof seal therebetween. Also, on or adjacent the side edges of the jacket 10 (i.e. the edges of the jacket which extend along the pipe 11 in use) strips of hook and eye fabric are provided to enable these edges to be secured together once the jacket has been wrapped around the pipe. One of these strips (referenced 18) is provided on the layer 13 and faces inwardly of the wrapped jacket, while the other strip (not visible in the drawings) is attached to the cover 12 and faces outwardly of the wrapped jacket.

Adjacent one side edge of the jacket 10, a bushing 19 is provided which passes through the cover 12, the block 14 of absorbent material and the layer 13. At its end projecting from the cover 12, the bushing 19 has a spigot 20 which provides a connector to which can be attached a tube or pipe (not shown) from a supply of refrigerant. At its end projecting from the interior of the jacket 10, the bushing 19 has a constriction 21 which serves to maintain the pressure of the refrigerant in the tube or pipe so that it does not freeze up in the latter.

In order to freeze the pipe 11, the jacket is wrapped around the pipe so that the block 14 of absorbent material lies against the external surface thereof, and is then secured in place by means of the strips of hook and eye fabric on the one hand and the tie cords 16 on the other hand. The spigot 20 of the bushing 19 is connected to a source of refrigerant, so that the refrigerant can then be supplied to a space 22 formed between the interior of the jacket 10 and the exterior of the pipe 11. As the refrigerant circulates within this space, it comes into contact with the block 14 and soaks into it so that all parts of the block (including those disposed in the aforementioned pockets) ultimately become saturated with the refrigerant.With the pipe 11 thus substantially surrounded by the refrigerant-bearing block 14, an ice plug subsequently becomes formed in the pipe in the conventional manner.

A variety of refrigerants can be used in putting the invention into effect, but the preferred example is chlorodifluoromethane since this permits a comparatively low refrigerant temperature to be achieved. The refrigerant may be supplied from any convenient source (such as a pressurised container), and it is preferred that a continuously adjustable valve #is provided somewhere in the supply line to regulate the rate at which the refrigerant is supplied to the jacket. Indeed, this valve may be incorporated onto the container itself.

The size of the jacket 10 will depend upon the diameter of the pipe 11 to be frozen, and tests have shown that the apparatus described above can be used effectively on pipes up to a diameter of 54 mm or more. Because the refrigerant is able to flow into and be held by the block 14 of absorbent material, a sufficiently good refrigerating effect is achieved that a single application of a defined amount reffigerant will enable an ice plug to be maintained for a significant period, i.e. there is no need for refrigerant to be supplied to the jacket substantially continuously. Furthermore, except in the case of very large diameter pipes, the ice plug forms relatively quickly and there is no need for a delay between terminating the supply of refrigerant to the jacket and commencing work on the pipe. Typical performance figures for the apparatus are as follows; Pipe Ambient Wt. of Supply Pause Life of dia. temp. refrigerant time period ice plug (mm) ( C) used (gm) (mins) (mins) (mins) 22 20.8 308 3 ~ 33 28 22.1 482 5 ~ 21 35 22.3 620 6 - 14.5 42 22.1 706 7 2 28 Moreover, because the apparatus is made from relatively inexpensive materials, it can be produced at a cost which is attractive to the amateur market.

Claims

1. Pipe freezing apparatus comprising a flexible jacket forwrapping around a pipe to be frozen, the jacket being composed of a substantially continuous layer of liquid proof material which forms an outer cover of the jacket when the latter is wrapped around said pipe in use, a layer of absorbent material attached to the cover and exposed to a surface of the jacket which confronts said pipe in use, passage means whereby a refrigerant medium can be introduced through the jacket from the exterior thereof and into the absorbent material, and securing means whereby the jacket can be secured to said pipe- in use.

2. Pipe freezing apparatus as claimed in claim 1, wherein the jacket also includes a second layer of liquid proof material, the layer of absorbent material is disposed between said layers of liquid proof material, and said second layer is apertured to expose the absorbent material at said confronting surface of the jacket.

3. Pipe freezing apparatus as claimed in claim 1 or 2, wherein the passage means comprises a bushing extending through the outer cover and the layer of absorbent material whereby the refrigerant medium can be introduced into a space formed between the jacket and said pipe in use and thence into the absorbent material.

4. Pipe freezing apparatus as claimed in claim 3, wherein the bushing has a constriction incorporated therein.

5. Pipe freezing apparatus as claimed in any preceding claim, wherein the refrigerant medium employed is chlorodifluoromethane.

6. Pipe freezing apparatus as claimed in any preceding claim, wherein the securing means includes means for clamping each end of the jacket to the pipe.

7. Pipe freezing apparatus as claimed in claim 6 wherein the means for clamping comprises tie cords.

8. Pipe freezing apparatus as claimed in any preceding claim, wherein the securing means includes fastening means on or adjacent to side edges of the jacket which extend along said pipe in use.

9. Pipe freezing apparatus as claimed in claim 8, wherein the fastening means comprises strips of hook and eye fabric.

10. Pipe freezing apparatus substantially as hereinbefore decribed with reference to the accompanying drawing.