ROV inspection of welds -- A reality
- Technical Software Consultants Ltd., Milton Keynes (United Kingdom)
Remote Operated Vehicles (ROV) have been in use since the early 1970`s but these could only carry out a limited number of mechanical tasks. During the 1980`s a new range of vehicles were developed that could carry out cleaning, visual inspection and flooded member detection, but were still unable to inspect welds. These tasks increased until it was possible to reduce the proportion of combined diving and ROV program to 10% for diving operations. New inspection techniques and computer aided manipulators were also being developed and were being combined in an attempt to resolve this inspection problem. Trials were carried out with electromagnets and eddy current techniques, but the problem of access and accurate weld tracking still produced problems. The development of the Alternating Current Field Measurement (ACFM) technique and its successful use during diving inspection made it a possible contender for use with an ROV. Because of its ability to detect and size surface breaking cracks without electrical contact or complex scanning procedures it is possible to produce inspection heads that do not need accurate placement by an ROV. A fully integrated ROV deployment system using ACFM multi element array technology has now been produced for a North Sea Operator. This can be used with any work class ROV and it does not require accurate weld toe tracking. This system has been subject to extensive tank Probability of Detection and Sizing Trials and a very high success rate was achieved with a very low number of false indications. In addition good sizing accuracy was produced for both length and depth measurements. Further front end tools have also been developed for different geometry`s and access.
- OSTI ID:
- 207979
- Report Number(s):
- CONF-9510265--; ISBN 1-57117-013-8
- Country of Publication:
- United States
- Language:
- English
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