The ClampOn Subsea Corrosion Erosion Monitor (Subsea CEM) is an ultrasonic instrument designed to measure wall thickness loss in pipes, plates or other metal structures. It uses active ultrasound where transducer pairs work in a pitch catch mode of operation, giving the average wall thickness between the transducers. As a part of the ClampOn family, it is non-intrusive.

A permanently installed CEM system will measure the wall thickness frequently and at a very high repeatability, thereby eliminating the weaknesses that are commonly encountered in manual ultrasonic thickness gauging. Wall thickness trends are generated automatically and can be observed in real time, logged internally in a datalogger or presented in a wireless solution. This technique has been installed topside and will now also be made available subsea.

The CEM uses up to 8 transducers, resulting in a coverage area of up to 65% of a selected pipe section and of up to 2 meters in length. The subsea version will utilize up to 32 transducers, increasing distance to a maximum of 8 meters. Installation is easy and the system virtually maintenance free, due to the newly developed Dry Contact transducers which utilize electromagnetism to transmit and receive acoustic signals. Therefore no glue is required and the transducers can be placed on the exterior on up to 3 mm of paint or coating. The CEM is a versatile instrument and can in practice be used to monitor all metal structures, such as:

• Subsea production templates
• Jumpers/Flow Lines
• Manifolds
• Retrofit solution

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