A rotary paddle level switch is a point-level device used to detect the presence or absence of bulk solid materials, such as powders, granules, and pellets, inside tanks, silos, or hoppers. It works by using a small motor to rotate a paddle blade. When the material rises to cover the blade, the rotation is blocked, which triggers a microswitch to output a signal and stops the motor. When the material level drops and the blade is free again, the motor restarts. It is simple, reliable, requires no calibration, and is unaffected by material properties like moisture or dielectric constant. With its stable performance, easy installation, and strong anti-interference capability, it is widely used for high and low level monitoring and control in silos across industries such as cement, chemicals, grain, feed, and plastics.