Device for measuring liquid level and converting it to an electrical signal to send to other instrumentation.
A liquid level sensor is an instrument for measuring the height of a liquid and converting it to an electrical signal which is sent to other instrumentation to display, monitor, log or control the liquid level.
There are many different types of technology use to measure liquid level, there are sensors that can be mounted above the liquid such as ultrasonic or radar which bounce a sound or electromagnetic wave off the surface of the liquid and use the travel time to determine the distance from the liquid surface.
For liquid filled tanks there are sensors which can be attached externally, such as floats running up and down a liquid filled tube connected at the bottom of the tank, or a pressure sensor installed in a hole in the bottom of the tank which measures the pressure generated by gravity acting on the liquid.
Another method is to lower a probe into the tank and immerse it in the liquid such as a capacitive probe which detects the changing capacitance charge as the length of the probe is exposed to varying proportions of liquid and air, or pressure sensors which measure the pressure generated by gravity acting on the surrounding liquid.
Product Types
Hydrostatic Level Sensors- ATEX Approved Liquid Level Sensors for Hazardous Areas
External Mounted Tank Level Sensors
Waste Water Level Sensors
Water Level Transmitters with 4-20mA Output
Chemical Resistant Hydrostatic Liquid Level & Pressure Sensors- 4-20mA Output Hydrostatic Level Transmitters & Sensors
Diesel Fuel Tank Level Sensors
Marine Approved Liquid Level Sensors
Submersible Liquid Level Sensors- Sea, Brackish or Salt Water Submersible IP68 Depth & Level Sensors
Submersible Hydrostatic Level Sensors & Probes- Low Range, Shallow Depth Liquid Level Sensors
Submersible Diesel Tank Level Sensors- 0-10 Volts Output Hydrostatic Sensors, Probes & Transducers
Water Resistant Pressure Sensors with Strain Gauge Output
Plastic Submersible 4-20mA Liquid Level Sensors- Marine Approved Submersible Liquid Level Sensors
Landfill Site Submersible Leachate Level Transmitters
Submersible Leachate Level Transmitters- Landfill Site Leachate Level Transmitters
Digital Submersible Liquid Level Sensors- HART® Liquid Level Transmitters
Detachable Cable Submersible Liquid Level Sensor Probes
Technology Comparison Table
Please use the table below to compare the advantages and disadvantages of each liquid level sensor technology type versus application and specification parameters.
| Capacitive | Hydrostatic | Ultrasonic | Radar | |
|---|---|---|---|---|
| media contact | yes | yes | no | no |
| moving parts | no | yes | no | no |
| surface disturbance sensitive | no | no | yes | no |
| pressurised vessel | yes | more difficult | yes | yes |
| vacuum evacuated vessel | yes | more difficult | no | yes |
| installation position | top | side, bottom | top | top |
| thick fluids | no | yes with flush diaphragm | yes | yes |
| protrusion into tank | yes | no | no | no |
| sg density variation sensitive | yes | yes | no | no |
| fouling degrades performance | yes | yes | no | no |
| accuracy | low | high | high | high |
| cost | high | high | high | high |
Related Guides
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- Hydrostatic Pressure
- Hydrostatic Liquid Level Sensors
- Choosing PVC, PUR, FEP and TPE cable types
- Determining water tank volume using hydrostatic pressure
- Using absolute pressure sensors to measure hydrostatic level
- How to reduce submersible pressure sensor failures caused by moisture ingress
- Why are Submersible applications so demanding of Pressure Transducers?
- Considerations for monitoring Landfill Water Level
- Improve the electrical termination of vented submersible pressure sensors
- Measuring liquid level in a sealed tank with a hydrostatic pressure sensor
- Determining the hydrostatic pressure range for a tank level sensor
- Using a screw-in or waterproof pressure transmitter to measure liquid level
- Measuring the volume of liquid in a horizontal cylinder tank
- Stop sea water level or depth sensor failures due to pitting or corrosion