ULTRASONIC LEVEL SENSOR – what is it?
The ultrasonic level sensors consist of two essential parts, a transducer (also called sensor) and an electronic control box. The transducer cannot work alone without the control box. The control box can be conveniently placed in a control room or some other location and connected to the transducers via coaxial cables. The transducers are mounted at the top of the tanks, pointing downward to the liquid’s surface.
A strong ultrasonic signal burst is then generated by the transducer and propagates through the air down to the liquid’s surface. The ultrasonic signal will not penetrate below the surface of the liquid, it will be reflected back to the transducer. The echo round trip time is then converted to level, which is defined as the actual depth of the liquid in the tank. It is important to mention that the measurement is not affected by specific gravity, viscosity or any other characteristic of the liquid being monitored.
Typical Ultrasonic Level Sensor for a single tank:
DISADVANTAGES of Ultrasonic Level Sensors are few:
- The only significant issue presents itself when the liquid produces a thick foam on the surface. This foam will absorb the signal. In such cases, if the foam cannot be removed, the ultrasonic level sensors should not be used. Fortunately, this rarely occurs.
- For the best accuracy and proper monitoring, the transducer requires a clear and unobstructed view of the surface it monitors, free of obstructions directly under it.