Float actuated devices for monitoring liquid level and activating switch contacts at predetermined liquid level thresholds.
A float liquid level switch is an instrument for monitoring the height of a liquid and tripping an electrical contact switch 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 a warning lamp, activate an audible alarm, or switch on a pump.
Featured liquid level measurement products
LMP307 Submersible Level Transmitter - Submersible level transmitter for measuring liquid level with a 4-20mA current loop or a 0-10V voltage output plus optional ATEX approval for intrinsically safe use in hazardous areas in ranges from 1mH2O up to 250mH2O. The LMP307 is suitable for use on potable water with no leaching, and can be supplied with a drinking water certificate according to DVGW and KTW.
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.
Float liquid level switches are threshold contact trip devices which typically consist of a buoyancy component which is typically a sealed hollow ball or cylinder which will float on a liquid, and either a shaft assembly for vertical mounting, or a hinge mechanism for horizontal mounting.
As the level increases and decreases a float will be pushed up or drop down. The float can be connected to a hinge that opens and closes or slides along a shaft.
The position of the float along the shaft or the opening and closing of the hinge can be detected by various means.
A vertical mount sliding float type level switch will have a permanent magnet incorporated into the float which slides up and down the shaft. A magnetic reed switch is positioned along the shaft to the required level set point. When the float passes over the reed switch it will open or close the level switch circuit.
A horizontal mount hinged type float level switch will incorporate either a microswitch or a magnetic reed switch, which is activated by an actuator or lever connected to the float.
Featured liquid level measurement products
LMK307 Submersible Waste Water Level Sensor - Submersible waste water level sensor with optional intrinsic safety certification for monitoring the level of sewage and effluent in water treatment plants.
DS200 Combined Hydrostatic Level Switch, Gauge and Sensor - Three in one hydrostatic level switch, digital level gauge and level sensor with level ranges from 1 mWG up to 600 mWG (3.3 to 1969 ftWG).
It is possible to fit more than one switch to shaft type float switch, and provide liquid level control for a number of separate processes which are activated at different levels.
A float level switch makes direct contact with the liquid to be measured, and therefore material compatibility must be considered.
Since there are no pressure sensitive components exposed to the inside of the tank it is possible to fit float level switches to sealed pressurised tanks.
Float liquid level switches can be designed to mount through the top, side or bottom of a tank. Side entry type float level switches have hinged floats, and top and bottom entry type float level switches have sliding floats.
Featured liquid level measurement products
Harbour seawater level sensor with digital display & relay outputs for tidal applications - Seawater compatible marine bronze level sensor with digital display and relay outputs for for tidal monitoring and controlling pumps and valves in harbour environments.
Battery powered, 10m range, diesel oil tank level gauge with submersible probe - Combined digital pressure gauge and submersible level sensor for measuring the quantity of diesel or oil present inside industrial storage tanks up to 10 meters high.
Advantages
- Different types available for top, side or bottom entry mounting
- Cheapest type of liquid level switch
- Simple design and construction
- Not sensitive to changes in SG & density
- Some types do not require power to operate
- Surface disturbances such as ripples, foaming and bubbling will not affect performance
- Dielectric constant or conductivity of fluid will not affect operation
- Different materials for media compatibility can be specified
- Vapours, condensation and mists will not affect operation
- Vacuum and low pressure sealed tank will not compromise buoyancy of float
Disadvantages
- Moving parts vulnerable to clogging, wear and tear, and damage
- Fouling can cause unreliable movement or seizure of float actuation
- Float actuation relies on liquid contact
- Turbulence in the fluid may cause the float to move
- Thick or sticky fluids may prevent the float from moving
- Regular maintenance to ensure nothing is restricting float movement
- Single point level switch with side entry type
- Float assembly protruding into liquid causing obstruction, attracting fouling and hygienic cleanliness issues
Featured liquid level measurement products
- Portable battery powered tank level gauge with submersible sensor - Is there anything portable that could be dropped into different sized and irregularly shaped tanks to measure the amount of change in liquid height?
Storm surge protected low range submersible river level transmitter - This submersible level transmitter offers accurate low range water level monitoring with high overpressure resistance for storm surge protection in rivers
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- Converting non-vented depth readings & barometric pressure to true depth
Related Technical Terms
- 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 Online Tools
- Liquid Level to Hydrostatic Pressure Calculator
- Fluid Depth, Density, Gravity, and Pressure Calculator
- Liquid Level Transmitter 4-20mA Current Output Calculator
- Vertical Cylindrical Shaped Tank Contents Calculator
- Horizontal Cylindrical Shaped Tank Contents Calculator
- Rectangular Shaped Tank Contents Calculator
- Pressure to Liquid Level Calculator
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Contact us about this Float Liquid Level Switches page to request more information, or to discuss your application requirements.