Ultrasonic Level Measurement

Ultrasonic Level Measurement

Ultrasonic Level measurement uses an acoustic transducer to emit ultrasonic pulses and calculates level from the time it takes for echoes to return from the material surface. Typically mounted above the process, it provides non-contact continuous level measurement in liquids and, in suitable conditions, bulk solids. The method is widely applied where simplicity and non-contact installation are priorities.

Benefits include straightforward installation, cost-effective continuous measurement, and minimal process wetted parts for many configurations. Ultrasonic sensors are particularly practical for open tanks and basins, and they can perform well in benign vapor spaces where the acoustic path remains stable. With proper setup, they provide reliable distance/level output suitable for pump control, basic inventory, and general-purpose level indication.

Key limitations relate to the acoustic propagation path. Temperature gradients, changing gas composition, heavy vapors, steam, or vacuum conditions can shift the speed of sound and weaken echo quality unless compensated. Foam, turbulence, and dust can scatter or absorb sound energy, reducing measurement reliability. Installation should avoid obstructions and account for sensor dead band near the transducer face; stilling wells or target plates may be used when needed.

Typical applications include water and wastewater wet wells, lift stations, clarifiers, equalization basins, chemical storage in compatible services, and general utility tanks. In solids, ultrasonic can be used for low-dust materials and moderate ranges where the surface is sufficiently reflective and the acoustic path is not heavily attenuated. It is also used for open-channel flow measurement when paired with weirs/flumes and appropriate linearization.

Integration commonly includes 4–20 mA and digital communications, along with relay functions for alarms or pump control. Reliable performance depends on correct range selection, temperature compensation strategy, mounting geometry, and periodic cleaning of the sensor face where condensation or dirt accumulates. Diagnostics that report echo quality and signal margin support proactive maintenance and troubleshooting.

Miller Mechanical Specialties, an exclusive authorized representative of sales and service for Endress+Hauser.