Float level switch is a simple structure, easy to use level control device, it does not need to provide power supply, no complex circuit, it has the advantages of small size than the general mechanical switch, long working life, etc.. The float and spring are made of PP material, which can be used in any nature of liquid or pressure and temperature. It is widely used in shipbuilding industry, generator equipment, petrochemical industry, food industry, water treatment equipment, dyeing and finishing industry, oil pressure machinery, etc.
 

Working Principle. 
The liquid level sensor is composed of a magnetic reed switch and a float, the float has magnetic material inside, one or more magnetic reed switches are set inside a closed non-magnetic metal or plastic tube, then the conduit is passed through one or more floats with magnetic material, and the fixed double ring is used to control the float and the magnetic reed switch in the relevant position, the float rises or falls with the liquid, using the contact point inside the ball near the beginning of the magnetic reed to produce The float rises or falls with the liquid, using the contact inside the ball near the beginning of the reed to produce the action of opening and closing, for liquid level control or indication (when the float is close to the reed switch is on; when it leaves the switch is off). 

Caution:
This float ball stroke is very small, only 10mm, if you need to control a wide range of high and low level, it is recommended to buy a double ball, or buy 2 single ball, you can achieve the upper and lower level control.