ALL about Float Level Switch - Professional manufacturer of sensors

1.The working principle of float level switch

1.1 Buoyancy principle

The float level switch is based on the float movement caused by the rise or fall of the level, and then controls the switching state of the circuit by mechanical or electronic means. Float level switch is mainly composed of float ball, lever, micro switch, etc. When the liquid level changes, the float ball moves with it, and triggers the micro switch through the lever mechanism, thus changing the on-off state of the circuit1.2

1.2 Control mode

Single point control：Trigger switch action (on or off) at specific level points with a single float switch
Multipoint control：Multiple float switches or a single float with multiple reed tubes trigger multiple signals at different level points

2.Classification and structure comparison

According to the installation method and functional requirements, the float level switch can be divided into three categories:

2.1 Side mounted float switch

Structure: The float ball is connected with the magnetic switch (reed tube) through the lever arm and is installed on the side wall of the container.
Features: Easy to install, suitable for small and medium-sized containers, low cost.

2.2 Cable float level switch

Structure: The floating ball is connected to the weight through a flexible cable. The end of the cable is fixed with a reed tube. The floating ball moves up and down with the liquid level to trigger the magnetic switch.
Application: In vertical installation scenarios such as deep Wells, sewage ponds, and water tanks, the cable length is adjustable.

2.3 Reed tube float level switch

Structure:The float is suspended vertically by connecting rod, reed tube or contact mechanism mounted on top, rod length can be customized (up to several meters).
Advantages: not affected by the precipitation of the medium, suitable for deep liquid level measurement, multi-stage series to achieve multi-point control.

3.Select key parameter expansion

3.1.Medium characteristic

Corrosive liquids should be made of stainless steel (such as 304/316L) or PP float.
Viscous liquids (such as oil) need to increase the float diameter or shorten the guide bar spacing.

3.2.Environmental requirement

Temperature range: Standard type is suitable for -20℃~80℃, high temperature type can withstand 150℃ (need to customize ceramic reed tube)

3.3.Installation mode

Horizontal side installation, vertical top installation, or bottom installation, depending on the container structure.

4.Installation and maintenance operations guide

4.1.Installation precautions

Avoid the disturbance area: keep away from the liquid inlet and agitator to prevent the liquid level fluctuation from triggering mistakenly.
Calibrate the water level: Before installation, use a multimeter to check the on-off status of the reed pipe and ensure that it is consistent with the actual liquid level (the density difference should be compensated in high temperature environment).

4.2.Troubleshooting process

Float stuck: Remove the cleaning guide rod and check whether the medium is crystalline or contains particles
Abnormal signal:

Measure the resistance of the reed tube. If the resistance is too high, the contact oxidizes and needs to be replaced.

Check whether the cable insulation layer is damaged (explosion-proof sealing is required in mining scenarios)

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