TPT July 2007

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Technology Update
43 July /August 2007
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:
Website:
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:
Website: