GB2404232A

GB2404232A - Internally mounted intumescent sleeve inside pipe section

Info

Publication number: GB2404232A
Application number: GB0317143A
Authority: GB
Inventors: Andrew Caselli; Raymond Mark Coates
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-07-23
Filing date: 2003-07-23
Publication date: 2005-01-26
Also published as: GB0317143D0

Abstract

A device without moving parts, for automatically shutting off a supply pipe 10 conveying dangerous fluids in the event of a fire, comprises a section 12 of pipe of larger diameter than the supply pipe interposed in the supply pipe, preferably by union nuts 24, and a sleeve 16 of intumescent material fitted within the larger diameter pipe and having the same internal dimensions as the supply pipe. The intumescent material expands greatly when heated so as to block the supply pipe. The surface 18 of the sleeve 16 preferably has an impervious coating of suitable plastics or metallic material to prevent possible contamination of the intumescent material by the fluid during its normal flow through the supply pipe, which might render the intumescent material ineffective.

Description

"Automatic Safety Shut-Off Device for Fluid Supply Pipes".

This invention relates to an improved safety device for the purpose of automatically shutting off a fluid supply pipe in the event of a fire.

The fluid may be of an inflammable nature which will greatly intensify a fire if the pipe melts, such as natural gas, coal gas or liquid fuel oil; or of a nature which will aggravate a fire such as compressed air or pure oxygen.

The invention is therefore of great potential value in both domestic and industrial situations including workshops and hospitals.

Known services for the aforesaid purpose include moveable valve parts which can stick, for example with age, and thus fail to operate.

The object of the present invention is to provide an improved safety device for automatically shutting off a fluid supply pipe in the event of a fire which has no moving parts and is therefore inherently more reliable than hitherto.

According to the invention, a safety device for automatically shutting off a fluid supply pipe in the event of a fire comprises a section of pipe of greater diameter than the supply pipe interposed in the supply pipe, and a sleeve of intumescent material disposed within said section of pipe with a bore not substantially smaller than the bore of the supply pipe.

eeeteeBeceee Àee Said section of pipe is preferably interposed in the supply pipe by means of union nuts.

Preferably, at least the bore of the sleeve has an impervious covering for the purpose of ensuring that the intumescent material is not rendered ineffective due to possible contamination by the fluid.

Preferably, also, the impervious covering is applied to all the surfaces of the sleeve.

The impervious covering may be a coating of plastics material.

Alternatively, the impervious covering may be metallic foil.

The invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 is a sectional side elevation of a safety shut-off device installed in a fluid supply pipe; Figure 2a is one half of a cross-section through the device in open condition for the free flow of a fluid, on a larger scale; and Figure 2b is the other half of the cross-section showing the device blocked as a result of a fire in order to prevent the flow of the fluid.

Referring now to the drawings, a safety device for automatically shuttingoff a copper pipe 10 supplying natural gas to a house, in the event of fire, comprises a section 12 of metallic pipe of greater diameter than the Be.

::: :e 'see. ces Àe pipe 10 with externally screw-threaded ends 14 within which there is disposed a sleeve 16 of intumescent material also known as thermo-reactive mastic which expands greatly when heated. The bore 18 of the unexpanded sleeve 16 is nominally the same as the bore 20 of the pipe 10 so as normally to permit the free unobstructed flow of gas as shown in Figures 1 and 2a. All the surfaces of the sleeve 16 have an impervious covering (not shown) consisting of a coating of suitable plastics material such as polyvinyl chloride for the purpose of ensuring that the intumescent material is not rendered ineffective, that is to say nonexpandable by heat, due to possible contamination by whatever fluid is being supplied. The section 12 is interposed in the pipe 10 by the expedient of forming flanges 22 on adjacent ends of said pipe at a suitable gap formed therein, and firmly securing each flange 22 to one of the screw-threaded ends 14 of the section 12 by means of a union nut 24. Each joint is made fluid-tight by wrapping the external screw threads in silicone tape (not shown) in well-known manner. Where adjacent soldered joints in the pipe 10 require the use of a blow-torch which will heat up said pipe, the section 12 is fitted without the sleeve 16, which is installed later by unscrewing one of the union nuts 24 and flexing the pipe 10 to allow entry of the sleeve into the section.

In the event of a fire, heat readily conducted therefrom along the copper pipe 10 causes the intumescent a: : esa e*; sleeve 16 to expand and fill the bore of the section 12 as shown at 26 in Figure 2b, thereby safely shutting off the flow of gas through the pipe 10 and avoiding rapid and dangerous spread of the fire. Without the device, the pipe 10 would melt and allow gas to escape thus greatly intensifying the fire.

The supply pipe can carry fluids other than natural gas as hereinbefore intimated.

In a modification, the impervious covering consists of metallic foil. In another modification, the impervious covering is applied only to the bore of the sleeve. In a further modification, where the nature of the fluid permits it, the impervious covering is dispensed with. In yet another modification, means other than union nuts are employed to fit the section in the supply pipe. # À À

Claims

Claims: 1. A safety device for automatically shutting off a fluid supply

pipe in the event of a fire comprising a section of pipe of greater diameter than the supply pipe interposed in the supply pipe, and a sleeve of intumescent material disposed within said section of pipe with a bore not substantially smaller than the bore of the supply pipe.
2. A safety device according to claim 1, wherein said section of pipe is interposed in the supply pipe by means of union nuts.
3. A safety device according to either of the preceding claims, wherein at least the bore of the sleeve has an impervious covering for the purpose of ensuring that the intumescent material is not rendered ineffective due to possible contamination by the fluid.
4. A safety device according to claim 3, wherein the impervious covering is applied to all the surfaces of the sleeve.
5. A safety device according to claim 3 or claim 4, wherein the impervious covering is a coating of plastics material.
6. A safety device according to claim 3 or claim 4, wherein the impervious covering may be metallic foil.
7. A safety device for automatically shutting off a fluid supply pipe in the event of a fire constructed, arranged and adapted to operate substantially as 43. .! t'';: s'al:e hereinbefore described with reference to, and as illustrated by, the accompanying drawings.