Scanning device for an air filter

A scanning device for an air filter being arranged to be mounted in a circular duct, comprising:

• a driving unit and a sampling unit, wherein
• the driving unit comprises an inner magnetic member and an inner magnetic member support element arranged inside of the circular duct and an outer magnetic member and a circular guiding rail arranged outside of the circular duct,
• wherein the sampling unit comprises a central rotation axis and a probe nozzle, the probe nozzle being rotatable about the central rotation axis, the central rotation axis being positioned at the center of the circular guiding rail,
• the inner magnetic member support element being attached to the sampling unit and extending in a radius direction of the circular duct,
• the inner magnetic member being arranged at an end of the inner magnetic member support element close to an inner surface of the circular duct,
• the outer magnetic member being engaged with the circular guiding rail, being arranged adjacent to the inner magnetic member at an outer surface of the circular duct, such that the probe nozzle is driven to rotate around the central rotation axis by a force of attraction between the inner magnetic member and the outer magnetic member by displacement of the outer magnetic member along the circular guiding rail when the scanning device is actuated.