Details:

FT-2  FT-3  FT-5  FT-7  FT22  FT33  FT55  FT77Microswitch used to indicate liquid presenceMicroswitch is environmentally friendly when in use and when disposed of.Stable operationCorrosion resistant with no exposed metal to offer long service life. Stable operation with liquids with suspended solids or sticky liquids.Flexible adaption to any environmentsEasy installation by just suspending the sensor. Multiple point versions are also available. (FT55, FT77)
Large and rugged terminal box for easy handling, with a cover not requiring screws or bolts.

Principle of Operation

The float is designed to have large buoyancy, and the center of the buoyancy is closer to the float bottom and the center of gravity closer to the cable. The float sinks in water when the liquid level is rising (SG = 1). Since the centers of buoyancy and gravity are not at the same point, the float tilts, and the steel ball inside the float rolls, causing the microswitch to close its contacts.
The float operates in a reversed manner when the liquid level is falling, that is, the float tilts the other way and the steel ball returns to its original place, causing the microswitch to open its contacts.