A filter includes a plurality of annular filter elements arranged in axially staggered relation. An axial flow path includes a plurality of flow path segments, some being filtered by a respective filter element, and others bypassing a respective filter element. Various combinations are provided.

An air filter has a filter housing. A first flat filter element and a second flat filter element, each having a filter medium body with an inflow surface and an outflow surface, are arranged in the filter housing. A flow guiding device selectively guides an air flow to be filtered through the first flat filter element and the second flat filter element in series or at least partially past the second flat filter element. The outflow surface of the first flat filter element and the inflow surface of the second flat filter element are spaced apart from each other and form a widening bypass channel. The filter medium body of at least one of the first flat filter element and the second flat filter element has an intrinsically changing height and has a reduced height in a region of a larger width of the bypass channel.

Air filter systems, filter bag assemblies, filter bags and corresponding methods are described herein. Air filter systems, filter bag assemblies, filter bags and corresponding methods are described herein. The filter bag assemblies include a flange assembly, a cage attached to the flange assembly, and a filter bag installed over the cage with an opening at the flange assembly. When installed in the dirty air chamber of the air filter system, a seal between the flange assembly and the tubesheet defining the dirty air chamber is provided by applying a seal force on the end of the filter bag assembly located proximate the access panel on the side of the dirty air chamber opposite the tubesheet. That seal force is transmitted to the flange assembly through the cage. The tubular filter bags may be in the form of triangular bags and/or may include bag support connectors at the closed end of the bag.

A filter assembly comprises a filter element and an outlet flange. The filter element comprises a filter media pack comprising a plurality of filter media layers stacked on top of each other to form the filter media pack. The filter media pack has an inlet surface being at an inlet portion of the filter media pack, and an outlet surface being at an outlet portion of the filter media pack. An outlet flange is coupled to the outlet portion of the filter media pack.