How to Resolve the Impact of Pressurization on Ultrasonic Level Meter Measurements

　　Many customers want to use ultrasonic level meters to measure liquid levels in pressurized tanks, but are concerned about potential interference. Here, Dayu Electronics staff use a case study to explain how to resolve the impact of the pressurization process on ultrasonic level meter measurements.

　　Ultrasonic level meters generally operate under normal atmospheric pressure. Although the transducers of many ultrasonic level meter companies can withstand pressures of 3-4 kg, these pressure resistance tests are conducted under static conditions and only verify the transducer's ability to withstand static pressure. No company has tested the overall impact on measurement accuracy.

　　A customer purchased a Dayu Electronics ultrasonic level meter for use on equipment that produces anchoring agents. The production equipment has two resin mixture storage tanks. Due to the viscosity of the resin, air pressurization is required to discharge the resin into packaging bags. The on-site working pressure in this case was 6 kg. The ultrasonic level meter itself can withstand pressures of up to 10 kg. Therefore, Dayu Electronics technical staff provided the following solutions:

　　First, ultrasonic transmitted signals propagate through air vibration. Before pressurization begins, the airflow inside the tank is stable, and the ultrasonic level meter can receive echo signals. After pressurization begins, the airflow forced into the tank by the pressurization pump is extremely turbulent, disrupting the airflow throughout the tank and destroying the vibration of the transmitted signal, causing the ultrasonic level meter to be unable to receive the reflected signal from the target. (Another possibility is that after the pressurized airflow enters, a mist-like substance forms inside the tank, causing ultrasonic scattering, which prevents the reflected target signal from being received.)

　　Second, when the pressure reaches 3 kg, the sound of the pressurized airflow inside the tank becomes deeper and lower in pitch, indicating that the driving force of the pressurized airflow is partially offset by the internal tank pressure. The airflow is no longer as violent, and its disruptive effect on the internal airflow is reduced compared to the initial stage, allowing the ultrasonic level meter to receive signals again.

　　Therefore, when using an ultrasonic level meter to measure liquid levels in a sealed tank, if air pressurization is used, buffering should be implemented before air enters the tank to avoid affecting ultrasonic level meter measurements.