Abstract: An air filter unit may include at least one ionization unit and at least one filter medium arranged downstream of the ionization unit. The ionization unit may include at least one corona discharge electrode, at least one counter-electrode, and at least one voltage source. The at least one filter medium may include at least one electret layer, at least one mechanically separating layer, and at least one electrically conductive layer adjoining the mechanically separating layer. In an airflow direction extending from an inflow side toward an outflow side, the electret layer, the mechanically separating layer, and the electrically conductive layer may be arranged one after another in this order.

Abstract: A method for manufacturing a filter medium comprising at least two filter plies according to which at least a first filter ply has a plurality of thermoplastically deformable fibres, by means of which the at least two filter plies are joined to each other in some areas. The method comprises forming, by means of at least two rolls of a pressing tool, at least one additional joining region configured in a web-like manner in the at least two filter plies in which the at least two filter plies are joined to each other.

Abstract: A filter material for an air filter may include a substrate layer on an inflow side and a fine-fiber layer on an outflow side relative to a flow direction. The filter material may include a connection region arranged between the substrate layer and the fine-fiber layer. The substrate layer, connection region and fine-fiber layer may include pores having an aggregate degressive pore size with respect to the flow direction. A combined thickness of the substrate layer, connection region and fine-fiber layer may be at least 0.35 mm. The substrate layer may include a cellulose material and have an impregnation of resin disposed along the inflow side. The resin may amount to approximately 22% by mass of the substrate layer.

Abstract: A filter element for a filter device may include a filter body having at least one filter material for filtering a fluid. The filter body may have a first side and a second side facing away from the first side. The filter body may include a plurality of body pores. The filter body may have a porosity that is lower on the first side than on the second side. A nano-fiber layer may be disposed at least partially on the first side.

Abstract: A filter element for a filter device may include a filter body having at least one filter material for filtering a fluid. The filter body may have a first side and a second side facing away from the first side. The filter body may include a plurality of body pores. The filter body may have a porosity that is lower on the first side than on the second side. A nano-fiber layer may be disposed at least partially on the first side.

Abstract: A filter material for an air filter may include a substrate layer on an inflow side and a fine-fibre layer on an outflow side relative to a flow direction. The filter material may include a connection region arranged between the substrate layer and the fine-fibre layer. The substrate layer, connection region and fine-fibre layer may include pores having an aggregate degressive pore size with respect to the flow direction. A combined thickness of the substrate layer, connection region and fine-fibre layer may be at least 0.35 mm. The substrate layer may include a cellulose material and have an impregnation of resin disposed along the inflow side. The resin may amount to approximately 22% by mass of the substrate layer.