The ultrasonic level measuring device is installed above the liquid surface and measures the level by generating a pulse of ultrasonic waves that bounce off the liquid surface below.
The instrument detects the echo, calculates the echo’s travel time and converts it to a level measurement as shown in Figure.
Acoustic Level Sensor
Specifically, the relation between distance from sonic transmitter/ receiver to the liquid surface and the reaching time is expressed in the following formula:
O&M issues to be taken care of are as follows:
• Ultrasonic level meters require little daily maintenance because they have no moving parts and work without contacting the measuring objects. However, the junction boxes have to be regularly checked for any water ingress
• Keep clear the area around transmitter / receiver
• Keep liquid surface without scum, foam, wave, etc.