Clean chemical storage at atmospheric pressure
Atmospheric tanks of clean, low-vapor chemicals can use a non-contact ultrasonic sensor when the surface is stable and the headspace is free of dense vapor or foam. For aggressive vapor, heavy foam, pressurized or hazardous service, switch to a Volivue radar liquid level sensor.
Confirm the site problem, the Volivue approach, and the expected operating benefit before final selection.
A contact sensor would need chemical-resistant wetted materials and frequent checks.
Non-contact ultrasonic keeps all electronics out of the liquid, with a compatible sensor face material by model.
Lower-cost continuous level for clean atmospheric chemistry, with an honest path to radar when vapor or foam is heavy.
Clean chemistry, calm headspace — and a clear line to radar
Atmospheric storage of clean, low-vapor chemicals such as glycols, lubricant additives and neutral process liquids can suit a non-contact ultrasonic liquid level sensor, because nothing touches the medium and the pulse crosses only quiet headspace. The decisive variables are vapor density and surface state: ultrasound needs a defined air path and a stable liquid surface to time the echo reliably.
Treat the boundary honestly at the planning stage. Dense vapor changes the speed of sound and attacks hardware above the liquid, persistent foam absorbs the pulse, and sealed or pressurized chemical vessels sit outside ultrasonic territory altogether. In those cases Volivue recommends moving directly to a radar transmitter with compatible wetted materials rather than tuning an ultrasonic device at its limits.
Mounting above the chemistry without joining it
Select the sensor-face material against the headspace atmosphere by model, mount on the top nozzle with the blind zone above maximum fill, and seal the nozzle so vapor cannot condense inside the sensor cavity. Any short stand-off pipe must respect the model nozzle-geometry rules, otherwise internal pipe echoes appear before the real surface and confuse commissioning.
Outputs follow the plant standard: 4-20 mA to the PLC, relays interlocking high-level cut-off of the transfer pump, and RS485/Modbus where the tank group reports into a Volivue dashboard. Document the media compatibility check in the project file with medium name, concentration and temperature, so the next operator knows why ultrasonic was approved for this tank and where its limits sit.
Four checks before ordering for atmospheric chemical tanks
- Record medium name, concentration and storage temperature, and confirm sensor-face material compatibility by model before quoting.
- Verify the tank is genuinely vented and stays at atmospheric pressure across fill, storage and transfer cycles.
- Assess the headspace honestly: low vapor and no persistent foam keep ultrasonic viable; anything denser belongs to radar.
- Plan the nozzle: blind-zone clearance above maximum level, a sealed cavity against condensation, and no protrusions in the beam.
The chemical gives off a slight vapor — how much is too much for ultrasonic?
Light, occasional vapor that disperses in a vented headspace is normally acceptable; dense or layered vapor shifts the speed of sound and bends the reading. As a practical rule, if vapor is visible or the smell is strong at the manway, ask for an application review — that is usually radar territory.
Can we keep the ultrasonic sensor if we later blanket the tank with nitrogen?
A nitrogen blanket usually means the tank becomes sealed and lightly pressurized, which changes the speed of sound and breaks the vented-tank assumption behind ultrasonic level. Plan the change as a technology switch: a Volivue radar transmitter measures through blanketing gas and keeps the same output signals, so the control side barely changes.
Five checks that decide the ultrasonic model, mounting, configuration and output scope.
Application review
We review medium, tank, vapor and foam to confirm ultrasonic fits or recommend radar.
Model and mounting selection
We size range, blind zone, output and nozzle or bracket mounting for your tank.
Configuration and tank profile
We set empty distance, blind zone and linearization so readings match real fill.
Commissioning support
We support installation, signal verification and PLC / SCADA integration on site or remotely.
Lifecycle support
We provide spares, documentation and guidance for expansions and technology changes.
Selection questions for engineers, procurement teams and site maintenance.
What is an ultrasonic liquid level sensor?
It is a non-contact sensor that emits an ultrasonic pulse from the top of a tank, times the echo from the liquid surface and converts that distance into continuous level, percent fill or a 4-20 mA / relay / RS485 signal, with no part touching the liquid.
When should I choose radar instead of ultrasonic?
Choose a Volivue radar liquid level sensor when the headspace has heavy steam or vapor, dense foam, condensation, the vessel is pressurized or sealed, or the area is classified hazardous. Radar is unaffected by vapor and works under pressure, where ultrasonic echoes weaken.
What liquids and tanks suit ultrasonic level?
Clean, vented, atmospheric tanks: water, wastewater, utility liquids and clean low-vapor chemicals with a stable surface. It is the cost-effective choice when pressure rating and vapor immunity are not required.
Does it measure volume or weight?
It measures level and distance to the surface. Volume or percent fill is derived from tank geometry and known density. It does not sense weight and is not a weighing instrument.
What is the blind zone?
The blind zone is a minimum distance below the sensor face where measurement is not reliable. The sensor must be mounted so the highest liquid level stays below this zone; the exact value is model-specific.
What outputs and protocols are available?
Standard outputs are 4-20 mA, relay thresholds and RS485 / Modbus, integrating directly with PLC, SCADA and the optional Volivue dashboard. An API can expose data to other plant systems.
Can it be used in hazardous areas?
Hazardous-area suitability is reviewed per project. Classified zones often require a different protection concept or a radar instrument; we confirm requirements before quoting and do not assume an approval that has not been verified.
Request an ultrasonic liquid level review
Tell us about your tanks, liquids and signal needs. We review the application, confirm whether ultrasonic suits the medium and return models, mounting and outputs – or recommend a radar liquid level sensor when conditions require it.