They are used for the level control in containers holding product in powder or granule form in potentially explosive environment in Category 1/2 dusty environments D (zone 20/zone 21).
The functioning is based on the slow rotation of a syncronous motor which turns the paddle which is placed in the container that wheel or is stopped according to the absence or presence of material.
Comply to Directive ATEX 2014/34/UE Group II, Category 1-2 D (zone 20/zone 21), Directive Electromagnetic Compatibility 2004/108/CE.