British Gas Plc

Peter S Clough

Adrian S Parkes

Gordon J Corbett

Colin N Barker

Frederick Farrington

Mansel Moore

Richard J Yeowart

A kit is provided for temporarily blocking the bore of a pipe through which a fluid flows, the kit comprising an expansible flexible bag seal which is inserted through a hole provided in the wall of the pipe and an apparatus for injecting into the bag seal a quantity of a material adapted to expand in situ in the bag seal and inflate the bag seal to seal against the inside of the pipe. The pipe may be a gas main and the material may be an expandable synthetic resin foam. The bag seal is removed by injecting thereinto a substance capable of dissolving the foam so that the bag seal can be at least partially deflated.

Temporarily blocking the bore of a pipe through which a fluid flows with

A method and kit is provided for temporarily blocking the bore of a pipe through which a fluid flows, the kit including an expansible flexible bag seal which is inserted through a hole provided in the wall of the pipe injecting into the bag seal. A quantity of a material adapted to expand in situ in the bag seal and inflate the bag seal to seal against the inside of the pipe is injected into the bag seal. The pipe may be a gas main and the material may be an expandable synthetic resin foam. The bag seal is removed by injecting thereinto a substance capable of dissolving the foam so that the bag seal can be at least partially deflated.

A cover (1) for temporarily covering a trench, e.g. in a thoroughfare such as a road or footpath, by extending over, and resting on the ground on opposite sides respectively of the trench, the cover (1) being releasably engageable with other adjacent covers (1a and 1b) by means of male members (5 and 5b) mating with respective corresponding female members (6a and 6) in such a manner that when the covers (1, 1a and 1b) are engaged in a ground resting position to form an assembly (7) of covers, one cover (1b) of the assembly can be disengaged from the adjacent cover (1) only by moving the cover (1b) out of the general plane of the assembly.

Cover for trenches

Joints and leaks in pipelines or mains are sealed by injecting into the joint or leak a sealant by means of an expandible tubular pig which is moved endwise through the pipeline or main. The sealant is in the form of an anaerobically curable monomer which cures in the relatively air free conditions in the joint or leak. The pig forms within the pipeline or main an air-free space which communicates with the joint or leak and which is isolated from the fluid in the main. Nevertheless the pig is hollow to permit the flow of fluid therethrough while the joint or leak is sealed. The sealant is injected into the joint or leak by way of the space so that the sealant cures in situ in the joint or leak.

Sealing joints and leaks

Sealing joints and leaks with an anaerobic liquid

Soluble thiosulphates present in aqueous redox systems comprising at least one salt of an anthraquinone di-sulphonic acid and at least one water soluble compound of metal having at least two stable oxidation states, for example a vanadate, are converted to sulphates by introducing oleum or sulphuric acid into the lower half of a vessel containing said thiosulphate containing redox solution, wherein the sulphuric acid has a concentration of from 10-98% w/w H.sub.2 SO.sub.4 and the amount of said sulphuric acid is such that the gram molecular weight ratio of sulphuric acid to thiosulphate is from 1:2 to 1:3, and thereafter separating the sulphate formed for example by using a solubility lowering technique. The process is carried out at ambient temperature and at a temperature of from 70.degree. C. up to the boiling temperature of the acidic mixture.

Growing community of inventors

Stretford, United Kingdom

Peter S Clough