Duct type shelter air conditioning units are designed to be mounted on the ceiling. The body of the unit is made of 1 mm galvanized sheet metal. The blowing fan is made of galvanized sheet metal with an external rotor motor. Additionally, the fan is statically and dynamically balanced. Inside the unit is a pre-filter G4 or F7 cartridge filter used, for the necessity in dangerous times an active carbon filter and a radioactive hepa filter has been placed in the unit. Optionally, a lead separator can be added and also the inner walls can be covered with lead plates. The System operation starts with the activation of the fan.
Under normal conditions, the filter damper is closed and the bypass damper is in open position, the sucked fresh air from the outside is pressed in after passing through the cartridge filter.
Dampers operate via a single lever. When the lever is turned, the bypass damper opens and the filter damper closes. Turning the lever in the opposite position the bypass damper closes and the filter damper opens.