Performance tests of a new non-invasive sensor unit and ultrasound electronics

Industrial applications require complete non-invasive setups due to high temperatures, pressures and possible abrasive fluids. Recently a new sensor unit was developed by Flow-VizTM that consists of several components such as a high power ultrasound transducer, wedge, attenuator as well as different couplant materials. The complete sensor unit setup enables non-invasive Doppler measurements through high grade stainless steel. However, the sensor unit still needs to be acoustically characterised and evaluated. In this work a non-invasive sensor unit for one inch pipes (22.5 mm ID) was evaluated. Performance tests were conducted using a Doppler string phantom setup and the Doppler velocity results were compared to the moving string target velocities. Eight different positions along the pipe internal diameter were investigated and at each position six speeds (0.1 – 0.6 m/s) were tested. Error differences ranged between 0.18 to 7.8% for the tested velocity range. The average accuracy of Doppler measurements decreased slightly from 1.3 to 2.3% close to the pipe wall towards the opposite pipe wall and was expected. The overall performance of the combined Flow-VizTM system (electronics, software, sensor) was excellent as similar or higher errors were typically reported in the medical field. This study validates the high performance and accuracy of non-invasive measurements through high grade stainless steel pipes using the Flow-Viz system.