TPT July 2007

Technology Update

that each end dam forms a seal. Once the dams are fully inflated, the pressure opens a valve to allow the inert gas to enter the space between the sleeve and the pipe and displace the air. Welding can begin as soon as the oxygen level is low enough. The flow of inert gas is maintained throughout the welding operation, to purge any oxygen released by the increasing temperature, and is continued until the completed weld has cooled to below oxidation temperature. The purge gas supply is then cut off and the system deflates to allow its removal from the pipe. Heat-resistant material protects the Argweld Quick Purge from high temperatures close to the weld. A weld purge monitor to indicate oxygen level can be connected to the Argweld Quick Purge systems, which are available in sizes for pipes between 200mm and 1,800mm in diameter. Other designs of pipe purging systems are available for pipe diameters from 50mm to 200mm. Argweld Quick Purge devices have been used by Bechtel for the Sabine Pass liquid natural gas 30" diameter pipeline in the USA, and by Ledwood Construction welding

a similar pipeline for the South Hook Project in Wales. Huntingdon Fusion Techniques Ltd – UK Fax: +44 1554 836 837 Email: geraldevans@huntingdonfusion.com Website: www.huntingdonfusion.com Digital computed radiography replaces film radiography Computerised Information Technology Ltd (CIT), UK, has launched its filmless, high definition, digital computed radiography technology, suitable for NDT inspections, replacing conventional film radiography. CIT’s digital computed radiography (CR) is an electronic system that enables radiographic images of products under examination to be generated and displayed on radiographic monitors. The image is captured directly on a phosphorous CR plate and scanning transmits the image on the viewing monitor. No intermediate steps or film processing are required to capture the image, and images are then archived on CD/DVD media.

Digital CR can inspect products that have welds or castings in metallic and non-metallic components for flaws that match the fine grain film radiography. With the acceptance of CEN and ASME standards, users in all areas of industry are replacing the conventional method of NDT film radiography with the digital CR technology. Key advantages are the elimination of film and processing costs, process simplification, electronic archival and project time scale reduction. CIT’s technology also complies with ISO12000 and environmental green policy requirements. Other benefits include the elimination of wet chemistry, flexible imaging plates to suit various NDT inspection requirements, reduced radiation controlled area, reduced source strength, and reduced exposure time – up to 80 per cent for gamma source and up to 40 per cent for X-ray source.

Computerised Information Technology Ltd – UK Fax : +44 1908 260 084 Email : scsood@btconnect.com Website : www.cituk-online.com

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J uly /A ugust 2007