Rotary Level Switches are suitable for powdery or grainy solids

The range of the level meters includes rotary level indicators suitable for solids. 
They consist of a probes rotated by electric motor, which meet greater resistance as levels rises. 
The increased driving torque of rotation is measured by an electromechanical or electronic device which thus indicates level. 

The rotary level sensors do not require calibration and offer excellent reliability.