Pressure Sensor Based on the Time-Interval Between Neighboring Longitudinal Waves

Pressure vessels, widely used in industries, are safety-critical equipment. Nonintrusive pressure measurement is aimed to monitor the pressure without destroying the vessel's integrity. Due to the acoustoelastic effect of ultrasonic waves, travel-time change of the critically refracted longitudinal wave (
${\rm{L}}_{{\rm{CR}}}$
wave) and reflected longitudinal waves can reflect the inner pressure of pressure vessel. Nevertheless, it has been identified that many factors, including coupling agent, exciting and receiving circuit of ultrasound, ultrasonic probes, and their mounting characteristics, have notable impact on travel-time measurement accuracy. In this article, a pressure sensor based on TDC-GP22 is designed. Additionally, a new method, adopting time-interval between neighboring longitudinal waves and multiple time-intervals fusion, is proposed, which can reduce the interference of factors mentioned above. Experiments are carried out to validate the method, and results show that the proposed method can achieve relatively accurate pressure measurement with mean relative error reduced to 3.61. Furthermore, model based on multiple time-intervals fusion without temperature compensation can also achieve relatively accurate pressure measurement (with mean relative error of 5.22), which can greatly simplify the measurement system.