Rotary vane sensor
Level measurement and verification – Systems for solids

This is a very simple device (figure 1 ), comprising a motor fitted with a gearbox, which turns a paddle or impeller at a low torque and a speed of the order of a few revolutions per minute. When the product rises and comes into contact with the rotating part, the movement is braked or stopped. An internal torque limiter then activates an alarm contact and stops the motor. If the product falls back down, the vane is released and the deactivated limiter starts the motor again, releasing the alarm contact.