Liquid Level Switches

Measurement and point detection devices for monitoring liquid level and activating switch contacts at predetermined liquid level thresholds.

A liquid level switch is an instrument for monitoring the height of a liquid and tripping a relay contact switch or transmitting a solid state relay switch output when a maximum, minimum or intermediate level has been reached. The liquid level switch output can then be utilised by other instrumentation to open a valve, illuminate an warning lamp, activate an audible alarm, or switch on/off a pump.

Featured liquid level measurement products

18.605 G Low Cost Submersible Diesel Fuel and Water Tank Level Sensor - Low cost OEM diesel fuel or water level sensor for installing inside or outside a storage tank.
LMK458 Marine Approved Hydrostatic Level Transmitter - Marine approved level transmitter with 4-20mA output for measuring level of contents inside ship ballast, fuel, liquid cargo or wastewater tanks

There are two basic types of liquid level switches, those that detect the presence of liquid known as point level detection, and those that are continuously monitoring the variation in level to detect when a threshold has been reached.

Point level switches have to be mounted so that the sensing probe makes contact with the fluid. They are simpler to set-up and calibrate, since the installation position dictates the switch point, however this also limits where the point level sensor can be installed.

There are many applications on a liquid storage tank where a switch provides a lower cost and simpler installation for managing tank contents because there is no need for additional signal conditioning instrumentation, and some switch types are mechanically activated and require no electrical supply or electronic circuits to function.

Featured liquid level measurement products

CIP protected dairy sensor for measuring level of milk in 6m high tank - Hygienic pressure sensor designed for CIP cleaning in dairy applications. Withstands harsh chemicals and high temperatures. Accurate and reliable level measurement in milk silos.
LMP307T Submersible Level and Temperature Transmitter - The LMP307T is a submersible level and temperature transmitter with a level sensing range from 1 to 250 mH2O and a temperature sensing range of 0 to 30°C up to 70°C.

Product Type Comparison Table

Please use the table below to compare the advantages and disadvantages of each liquid level switch technology type versus application and specification parameters.

	float	conductivity	capacitive	hydrostatic	tuning fork	ultrasonic
media contact	yes	yes	yes	yes	yes	no
moving parts	yes	no	no	yes	yes	no
surface disturbance sensitive	no	no	no	no	no	yes
pressurised vessel	yes, low pressures	yes	yes	more difficult	yes	yes
vacuum evacuated vessel	yes	yes	yes	more difficult	yes	no
installation position	top, side, bottom	top, side, bottom	top	side, bottom	top, side, bottom	top, side
thick fluids	no	no	no	yes with flush diaphragm	no	yes
protrusion into tank	yes	yes	yes	no	yes	no
sg density variation sensitive	no	no	yes	yes	yes	no
fouling degrades performance	yes	yes	yes	yes	yes	no
multiple point level detection	vertical entry yes, side entry no	vertical entry yes, side entry no	yes	yes	vertical entry yes, side entry no	top entry yes, side entry no
accuracy	low	low	low	high	high	high
cost	low	low	high	high	high	high
power supply required	no	yes	yes	yes	yes	yes

Featured liquid level measurement products

Low power consumption fuel tank level sensor - Reliable and accurate fuel level measurement in remote locations. Battery-powered with low power consumption.
Water tank level gauge transmitter with adjustable range - We are looking for level measurement gauge transmitters for water tanks used for domestic water and fire water in a hotel.