Precision Acoustics offers transducer optimisation facility

From time to time Precision Acoustics are asked to undertake design refinements on pre-existing transducers. This could range from a simple modification through to a comprehensive product review and re-design. It has often been the case that a detailed scientific understanding of ultrasonic transducers, combined with years of experience in hydrophone/transducer production can lead to significant product enhancements.

To illustrate the type of optimisation work carried out a couple of case studies are presented below:

Case study 1: Haemodynamic monitoring transducer

Deltex Medical approached Precision Acoustics to undertake some acoustic output measurement on some prototype transducers for their next generation of equipment. The results of this and additional third party measurements indicated that the transducers were performing differently from initial expectations.

Precision Acoustics followed this with a design review of the prototype transducers, and this process revealed that impedance mismatch problems were a significant factor in the non-optimal performance of these transducers. Precision Acoustics were then commissioned to design and implement some impedance matching networks for these prototype devices. Once these networks were installed there was a significant increase of acoustic output of the transducers, as well as a marked improvement in their third harmonic rejection.

Case study 2: Reference sources for national standard calibrations

Monitoring of acoustic emissions is a rapidly growing industry, but as yet there is little in the way of standardisation. It was felt by the National Physical Laboratory (NPL) (London) that one of the key limitations was the absence of a repeatable, calibrated reference source. Their initial prototype source was found to have some serious limitations, and Precision Acoustics were asked to produce a second-generation device.

The device that was developed comprised a transducer casing into which a range of different conical piezo-electric elements could be fixed. The inter-changeability allowed a number of different configurations to be examined in order to determine the optimum transducer geometry. The entire active assembly was sprung loaded to ensure that the apex of the conical element was always in contact with the calibration test block. Initial results indicate that this re-design shows significant improvement in performance over the original device.

Another branch of NPL needed a reference source for use as part of their hydrophone calibration service. Existing transducers were only available over limited bandwidth and this was limiting measurement efficiency. Precision Acoustics produced a customised piezo-composite transducer with sufficient signal to noise ratio that it could be used for calibration in the range 0.1 MHz to 1.6 MHz

If you would like further information about Precision Acoustics range of transducers, optimisation and consultancy services, please visit www.acoustics.co.uk.