Phase controlled EMAT antenna for the inspection of coated pipes
The new inspection technique for the testing of pipes and pipelines by the EMAT-antenna was demonstrated. The technique allows carrying out fast pipeline inspection. It was shown, that the pipes with bitumen coating can be inspected without removal of the coating. Some advantages of the presentation and documentation of inspection data were eleborated , which improve evaluation of inspection results. The inspection technique can also be applied to pipes and pipelines with coating of polymers, concrete or bitumen of thicknesses up to 3mm. The inspection system is optimised for the detection of corrision damages. It is demonstrated that with proper design the sensitivity of EMAT- sensors can be improved. The necessary signal-to-noise ratio is achieved by the application of an averaging algorithm in combination with an optimised phased addition of signals from the receiving channels. Special algorithm for optimal focusing increases the amplitude of the resultants signals. An inspection system for field applications using the described features is under development.