Ultrasonic level sensors work by utilizing principals of sound to offer continuous measurement of both liquid and solid media.
The top-mounted sensor emits a high-frequency pulse of ultrasonic sound (meaning on outside the hearing range of humans), then records the time it takes for the echo to return. Based on the speed of sound, the distance from the sensor to the top of the liquid media can be calculated by dividing the time between the initial pulse and its echo by two. The principal is similar to the echolocation used by bats and dolphins.
Ideal Uses for Ultrasonic Liquid Level Sensors
Because they use no moving parts, ultrasonic level sensors are ideal for applications in which contact with the medium being measured is impractical. This includes those involving boiling liquids and caustic chemicals. Ultrasonic sensors can also produce accurate point-level or continuous measurements for materials with inconsistent chemical compositions or dielectric constants.
Disadvantages of Ultrasonic Level Sensors
Ultrasonic level sensors may be inappropriate for certain materials that hamper the quality of a sensor’s received echo. Some materials may absorb the ultrasonic sound waves rather than reflecting them, in which case a different sensor technology would be more useful. The same is true for applications with very high tank depths, in which case a downhole submersible level sensor would be preferable.
Ultrasonic Liquid Level Sensors from SMD Fluid Controls
If you need industrial level sensors in the United States or the United Kingdom and think an ultrasonic model would be best for your application, SMD Fluid Controls offers a full line of ultrasonic sensors in addition to custom solutions.
The FL50 ultrasonic liquid level sensor is made from NPT nylon or polypropylene for chemical resistance that makes it ideal for applications involving hydraulics or oils. The FL50 can work in temperatures up to 90°C and pressures up to 150 PSI.
SMD’s FL stainless steel ultrasonic level sensors, including the FL-LL50 and FL5K, boast even greater chemical resistance than the FL50, in addition to maximum operating pressures of up to 5,000 PSI. Switched relays or digital outputs are available according to your needs; ideal industries are those involving wastewater, industrial slurries, acids, and foods or beverages.