Four proven technologies for every liquid level application
An ultrasonic transducer mounted above the liquid surface emits a sound pulse. The pulse reflects off the liquid surface and returns to the sensor. The time-of-flight is measured and converted to a distance, which is subtracted from the mounting height to give the liquid level.
Ultrasonic sensing is ideal for clean liquids in open or vented tanks. It is non-contact, so there is no risk of contamination or corrosion.
A submersible pressure sensor is placed at the bottom of the tank. The sensor measures the hydrostatic pressure exerted by the liquid column above it. Since the pressure is proportional to the liquid height, the level can be calculated accurately.
Pressure sensing works for clean and dirty liquids, slurries, and wastewater. It is unaffected by foam, vapor, or dust.
A capacitive sensor is mounted on the outside of the container wall. The sensor detects changes in capacitance caused by the presence or absence of liquid at the sensor location. No contact with the liquid is required.
Capacitive sensing is ideal for small containers, chemical compatibility, and applications where drilling is not possible.
An infrared LED emits light into a prism at the sensor tip. When the tip is in air, the light reflects back to the detector. When the tip is submerged in liquid, the light refracts out, and the detector signal changes. This provides a fast, reliable point-level detection.
Optical sensing is ideal for high/low level alarms, overflow prevention, and pump control in small tanks.
| Technology | Range | Accuracy | Contact | Best For |
|---|---|---|---|---|
| Ultrasonic | 20mm – 2000mm | ±(5mm + S×0.5%) | Non-contact | Clean liquids, open tanks |
| Pressure | 0 – 10m | ±0.25% FS | Submersible | Wells, wastewater, slurries |
| Capacitive | Point-level | ±1mm | External | Small containers, chemicals |
| Optical | Point-level | ±1mm | Contact | Alarms, overflow prevention |