Flexible ultrasonic multi-element transducer array
Methods
Flexible ultrasonic multi-element transducer array
Keywords Rightrax, Transducers
A flexible transducer array, which has been developed to allow permanent installation on pipelines as an alternative to large numbers of conventional ultrasonic transducers, is now available from Rightrax Systems Ltd, of Warrington, UK.
The Rightrax-M1 system is produced as a thin strip carrying 14 separate sensors and can be fitted easily in areas of plant which are difficult to inspect by conventional means and in areas which are hostile or afford difficult access. The transducer array can operate at temperatures up to 110°C and will, it is believed, significantly reduce the cost of regular or continuous corrosion monitoring.
Essentially, each array is produced from very thin strips of piezoelectric film which can be in polyvinylidene fluoride (PVDF) or copolymer, depending on the required operating temperature. Both surfaces are covered with a thin metallic electrode and one of these surfaces has the continuous electrode arranged into a series of conductive pads and tracks. Each of the pads constitutes a transducer element and the series of 14 elements is connected by the conductive tracks to a small enclosure fitted to the end of the strip. This enclosure contains an electronics module, a temperature sensor and a small calibration block and is fitted with a single, weatherproof, coaxial connector.
The Rightrax M1 ultrasonic transducer fitted to a pipe
The electronics module includes:
a multiplexer;
a single chip microprocessor with a small amount of memory, containing parameters such as a user-defined identity name, and;
an interface to the single coaxial cable.
When the cable is connected to a customised data logger or, via a customised interface, to a conventional ultrasonic test set, it is used not only to excite an ultrasonic sensor but also to control the multiplexer to select one of the 14 ultrasonic sensor elements, the calibration block or the temperature sensor, or to read the sensor's identity name. Multiple M1 sensors can be connected to a single coaxial cable.
Transducer strips are simply attached to structures by means of an integral double-sided adhesive tape, which also provides the acoustic bond. They can be further weather-proofed by covering with lagging or insulating compounds.
As the transducer elements are an integral part of the strip, the Rightrax-M1 is extremely thin and,consequently, can be attached to complex geometry plant and small radius pipe bends without significant crumpling.
Further details available from: Rightrax Systems Ltd, UK. Tel: +44 (0) 1942 742082; Fax: +44 (0) 1942 742082.
