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
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. 
Waste Water Level Sensors - Waste water Level sensors with open face flush diaphragms for measuring the hydrostatic pressure of sewage and effluent waste. Select a level sensor for mounting inside or external to a tank or sewer pipe.
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.
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.
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.- Sea, Brackish or Salt Water Submersible IP68 Depth & Level Sensors - IP68 rated transmitters and transducers suitable for use with tidal and coastal salt water.
Low Range, Shallow Depth Liquid Level Sensors - Level sensors for measuring very low liquid levels in shallow rivers, weirs, drains, sewers, streams and small tanks which are immersed or mounted on the outside of a tank.
Corrosive Chemical Compatible Flush Diaphragm Liquid Level Sensors - Fluid level sensors with plastic bodies and flush ceramic diaphragms for use with corrosive chemicals where no metal parts can be exposed to the media.
Flush Diaphragm Liquid Level Sensors - Liquid level sensors for wastewater and slurry applications requiring measurement of a few metres of liquid height with an open face diaphragm to prevent clogging.- Intrinsically Safe Liquid Level Sensors - Liquid level sensors with intrinsic safety approval for measuring the level of fluid contents where flammable gas or dust is present.
- 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.
Submersible Diesel Tank Level Sensors - Diesel fuel oil storage tank device for measuring liquid level and converting it to an electrical signal to send to other instrumentation protected from diesel ingress when completely immersed in the fuel oil.
Plastic Submersible 4-20mA Liquid Level Sensors - Plastic based chemical resistant casing material, protected from liquid immersion, 4 to 20 mA current output signal liquid level sensor.- Marine Approved Submersible Liquid Level Sensors - Marine approval certification for use on ships. Protected from liquid ingress when completely immersed in a fluid. Device for measuring liquid level and converting it to an electrical signal to send to other instrumentation.
Landfill Site Submersible Leachate Level Transmitters - Sensing transmitter devices protected from liquid ingress when completely immersed in a leachate for measuring leachate level and converting it to a 4-20mA current output signal to send to other instrumentation on a landfill site used to bury waste material.
Submersible Leachate Level Transmitters - Sensing transmitter devices protected from liquid ingress when completely immersed in a leachate for measuring leachate level and converting it to a 4-20mA current output signal to send to other instrumentation.- Landfill Site Leachate Level Transmitters - Sensing transmitter devices for measuring leachate level and converting it to a 4-20mA current output signal to send to other instrumentation on a landfill site used to bury waste material.
Digital Submersible Liquid Level Sensors - Digital communications protocol interface sensors protected from sustained immersion in liquid to prevent damage to internal sensor components, for measuring liquid level and converting it to a reading which can be transmitted using a digital communication link to other instrumentation.- HART® Liquid Level Transmitters - HART liquid level transmitters for configuration via a distributed control system (DCS) or HART communicator.
Detachable Cable Submersible Liquid Level Sensor Probes - Sensor probes with removable submersible signal cable for measuring liquid level. These sensor probes can be easily replaced without the need to remove the installed cable assembly or break connections to cable junction boxes and termination enclosures.
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 |
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Related Definitions
- Capacitive Fluid Level Measurement
- cmH2O – Centimetres of Water Column at 4 deg C Pressure Unit
- Conductive Fluid Level Detection
- Float Fluid Level Detection
- ftH2O – Feet of Water Column at 4 deg C Pressure Unit
- mH2O – Metres of Water Gauge at 4 deg C Pressure Unit
- mmH2O – Millimetres of Water Column at 4 deg C Pressure Unit
- Specific Gravity
- Vibrating Tuning Fork Fluid Level Detection
Related Tools
- Pressure to Liquid Level Calculator
- Liquid Level to Hydrostatic Pressure Calculator
- Fluid Depth, Density, Gravity, and Pressure Calculator
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- Horizontal Cylindrical Shaped Tank Contents Calculator
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