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.
Products
Hydrostatic Level Sensors - Hydrostatic pressure sensing devices for measuring liquid level and converting it to an electrical signal to send to other instrumentation.- ATEX Approved Liquid Level Sensors for Hazardous Areas - European hazardous area ATEX approved sensors for liquid level measurement in intrinsically safe installations on petrochemical, pharmaceutical, landfill and sewage treatment sites.
External Mounted Tank Level Sensors - External mounted level sensors for installing on the outside of a liquid storage tank to measure level of tank contents. 
Water Level Transmitters with 4-20mA Output - 4 to 20 mA current loop output water level transmitters with a for use with process instrumentation for measuring the level of water in a water well, water reservoir, river or water storage tank.
Chemical Resistant Hydrostatic Liquid Level & Pressure Sensors - Pressure transmitters & transducers that are resistant to chemical corrosion for measuring the hydrostatic level of storage tanks or process pressures.- 4-20mA Output Hydrostatic Level Transmitters & Sensors - Liquid level transmitters with a 4 to 20 milliamp current loop output signal for determining liquid depth or the fluid level by measuring the hydrostatic pressure.
Submersible Liquid Level Sensors - Devices protected from liquid ingress when completely immersed in a fluid for measuring liquid level and converting it to an electrical signal to send to other instrumentation.
Marine Approved Liquid Level Sensors - Devices with marine approval certification to use on ships for measuring liquid level and converting it to an electrical signal to send to other instrumentation.
Diesel Fuel Tank Level Sensors - Diesel fuel oil storage tank device for measuring diesel fuel level and converting it to an electrical signal to send to other instrumentation.- High Temperature Liquid Level Sensors - Liquid level sensors with cooling elements for isolating a high media temperature or where the whole device can be submerged in a hot fluid.
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 Help Guides
- Measuring liquid level in a sealed tank with a hydrostatic pressure sensor
- Determining water tank volume using hydrostatic pressure
- Choosing PVC, PUR, FEP and TPE cable types
- Difference between vented and non-vented water level measurement
- Measuring the volume of liquid in a horizontal cylinder tank
- How to reduce submersible pressure sensor failures caused by moisture ingress
- Using absolute pressure sensors to measure hydrostatic level
- Determining the hydrostatic pressure range for a tank level sensor
- Using a screw-in or waterproof pressure transmitter to measure liquid level
- Improve the electrical termination of vented submersible pressure sensors
- Considerations for monitoring Landfill Water Level
- Why are Submersible applications so demanding of Pressure Transducers?
- Determining the Signal Cable Length of a Suspended Liquid Level Transducer
- Stop sea water level or depth sensor failures due to pitting or corrosion
