Rotary paddle level switch SEM

for bulk materialsthreaded

The level controls propeller indicators SEM are employed for level control in tanks that contain powders or granulars. The indicators working is very simple: a synchronous motor that rotates at low speed activates a propeller placed inside the tank to be controlled. In lack of material the motor is under voltage and the propeller revolves. The presence of material round the propeller bridles the rotation provoking control contacts exchange; another microswitch induces then the dump of the motors feeding voltage. Electric circuit opening and closing causes the command of an acoustic or visual signal, or the silos load, the conveyors and worm conveyors stop etc. The instrument is mounted on the external wall of the tank, on the side or on the top. The material should be free to move round the propeller, that should be not fouled by the material direct jet: so arrange baffles on the indicator when weight on propeller is high (high specific weight material or subject to move in block ones). Version: SEM 24VCC/S with inverter board uses a synchronous AC motor (brushless) driven by an electronic board, integrated in the housing, which converts the tension from DC to AC. The use of a brushless motor solves the typical problem of DC motors which have a limited lifetime due to the wear on the brushes.