TPi April 2012

inspect ion equipment

Laser, video and ultrasonic inspection of pipe root welds

Dr Richard Gooch, director of technology at OMS, commented, “On this project, the pipes on the modular valve manifold system were almost entirely lined with a

UK-based specialist pipe measurement technology company Optical Metrology Services (OMS) Ltd has successfully completed an on-site internal weld inspectionsurvey for amajoroil company. The company used a combination of laser, video and ultrasonic inspection methods to inspect the profile of root welds on pipes. The survey was carried out by OMS’s US-based operation. In late 2009, OMS was approached by a main contractor on an oilfield project and asked to provide a team of on-site inspectors to carry out a full inspection survey of a number of subsea modular valve manifold systems. Using its laser- based dimensional measurement tools and video-based inspection systems, OMS was responsible for assessing the internal root welds for any defects. The inspection requirements covered the full range of weld features including crown height, undercut, porosity and burn-through. OMS’s on-site inspectors were also required to perform inspections at welding temperatures (ie up to 250ºC). In order to do this, OMS adapted its own weld inspection technology to enable it to operate at these elevated temperatures.

While ultrasonic or radiography technology is commonly used to inspect pipe root welds, this technology is not so effective when the weld defects are very small. OMS provided a team of three inspectors at site, one of these being a fully certified weld inspector. “The modular valve manifolds are mounted on 30ft skids and are critical junctions within oil or gas pipelines,” said Dr Gooch. “Our inspection tools were able to pass around 90º bends and 33º bends in the pipework, as well as inside the valves themselves. In order to do this, OMS designed a special laser-based measurement system that incorporated a slide rail, stepper motor and optical laser sensor. This allowed us to push the tool in very small, half- millimetre steps through the pipes to inspect the profile of the welds.” Optical Metrology Services Ltd – UK info@omsmeasure.com www.omsmeasure.com

special corrosion resistant material. Our team of three inspectors therefore had to make sure they didn’t overheat these coatings whilst carrying out inspections. “On average, it was taking the customer around four days to complete a root weld pass. If there were flaws in a weld, this would have to be repaired or cut out. Our inspectors carried out their inspections immediately after the hot pass. “The laser and video-based inspection of root welds took approximately 10 minutes to complete. In this time, we gave our initial verdict to the customer’s QA engineer on whether we thought there was a problem with the root weld. If we were uncertain, the laser inspection procedure was repeated but this time at finer detail [every 0.5mm] than before and double-checked using video-based inspection technology. The depth of the weld feature could then be examined more closely and a final verdict reached.”

ITP system revolutionises tube inspection PFW Nuneaton has installed four ITP tube inspection systems at its site to cope with the stringent inspection requirements of its customer – a UK aero engines company. On its latest contracts the customer only supplied the 3D CAD model of the tube assembly, but no fixtures or drawings. production for initial tube inspection, fitting orientation and final inspection. The customer praised PFW’s achievements, stating that the integrated production system created by PFW, based on the ITP tube inspection systems, was ground- breaking, and that they had never seen the level of throughput achieved at any other company. PFW production engineer Adam Treadwell said that the company could never have fulfilled the current contract without the ITP systems, which have allowed CAD data extraction, tube and fitting inspection and geometric measurement such as True Position, all on the same integrated system. PFW has found that the ITP inspection systems’ accuracy, flexibility and ease of use have outperformed other tube inspection systems within the group.

PFW used the ITP software to extract the tube and fitting data from the model and then export the data to the benders and the CMMs with no keyboard data entry required. The ITP systems are then used at all stages of

PFW says that this increase in capability has seen its tube assembly production quadruple compared to its competitors.

ITP Group – UK software@itpgroup.co.uk www.itpgroup.co.uk

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Tube Products International April 2012

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