A filter element is provided with a support frame provided with a first end disk section and a second end disk section. A folded filter medium is connected to the support frame and arranged between the first end disk section and the second end disk section of the support frame. The first end disk section or the second end disk section has a face facing away from the filter medium. The support frame is provided with a fluid guiding channel that guides, when a fluid flow passes through the filter medium, the fluid along the face facing away from the filter medium. A filter assembly with such a filter element and a filter receptacle in which the filter element is exchangeably arranged is provided.

A filter element has a preferably multilayer structure of a pleated filter medium (3) with a plurality of individual filter pleats (5, 7). Due to an alternating sequence of filter pleats (5) with a first pleat height (h1) and filter pleats (7) with a second pleat height (h2), more effective filter surfaces are available than with filter pleats with a uniform pleat height. Upon throughflow by a fluid to be filtered, a lower surface load for the filter medium (30 and lower passage speed of the fluid are present during filtration. A static loading of the filter medium (3) during operation of the filter is then reduced. A hydraulic circuit has such a filter element (1).

The invention features a filtration segment having a top seal, a bottom seal and a primary filter core and the method of filtering with the design of the filtration segment. The primary filter core is operatively coupled to at least one opening which is located either on the top seal or on the bottom seal. The filtration segment also includes one or more interior filters surrounding the primary filter core. Each interior filter includes a filter material surrounding a secondary core which is operatively coupled to at least one opening which is located either on the top seal or on the bottom seal. Each filter may optionally include a retaining medium enclosing the filter material. The filtration segment has one or more layers of an exterior filter media which operatively surround the interior filters and are operatively coupled to the top seal and the bottom seal.

A filter device has a support part (39, 43) receiving a filter part (1), a sealing device (17) acting between the support part (39, 43) and the filter part (1), and a securing device (53, 57, 61) releasably connecting the support part (43) to the filter part (1). The securing device has a circumferential collar part (53) that, under the action of an energy store (61), exerts a force on the sealing device (17). That force seals the support part (39, 43) and the filter part (1) in a fluid-tight manner with respect to one another. The support part (39, 43) has, on its end region oriented toward the securing device (53, 57, 61), another circumferential collar part (39). The collar part (53) of the securing device (53, 57, 61) is guided concentrically within the collar part (39) of the support part (39, 43) provided with a sealing system (41, 72).

A filter element for fluids, in particular for hydraulic fluid, has a foldable filter casing (10) with at least one filter layer (18, 20, 22, 24) extending between two end caps (26, 32). To vary in regions the thickness of the filter casing (10), the height (h.sub.1) of each filter fold (12, 44) increases from one end cap (26) to the other end cap (32). Alternatively, with the filter fold height (h.sub.1) being maintained, the outer diameter (40) of the filter casing (10) varies in the direction of one of the end caps (26, 32).

A scaling tool for replicating filtration characteristics of a large-scale filtration device, the scaling tool comprising a housing having a fluid inlet and a fluid outlet, and a filter receiving region in fluid communication with the fluid inlet and the fluid outlet and configured to contain a membrane comprising one or more pleats, the filter receiving region being defined by a rigid wall framework configured to hold the one or more pleats of the membrane and compress the pleats in an amount effective to replicate the filtration performance of the large-scale filtration device. Also disclosed is a methodology for configuring a filter receiving region in a scaling tool.

A filter insert for a filter for filtering a fluid having] an inflow surface, and outflow surface, and a main throughflow direction. A filter body of the insert has a filter medium with pleats forming a pleated bellows, are arranged perpendicular to the main throughflow direction. A first number of the pleat edges form the outflow surface and a second number of the pleat edges on a pre-filtration side of the filtration body form the outflow surface. A first seal prevents the fluid from overflowing from the pre-filtration side to the post-filtration on a surface formed by a first number of of end face of the pleats. A second seal prevents the fluid from overflowing from the pre-filtration side to the post-filtration side on a surface formed by a second number of end faces of the pleats.

A filter element has a preferably multilayer structure of a pleated filter medium (3) with a plurality of individual filter pleats (5, 7). Due to an alternating sequence of filter pleats (5) with a first pleat height (h1) and filter pleats (7) with a second pleat height (h2), more effective filter surfaces are available than with filter pleats with a uniform pleat height. Upon throughflow by a fluid to be filtered, a lower surface load for the filter medium (30 and lower passage speed of the fluid are present during filtration. A static loading of the filter medium (3) during operation of the filter is then reduced. A hydraulic circuit has such a filter element (1).

A filter element for filtering liquids has a folded filter medium with outer fold edges and inner fold edges, wherein the inner and outer fold edges extend along a longitudinal axis of the filter element. A support body is provided with a first support body section and a second support body section, wherein the first support body section is facing the inner fold edges and hugs closely an envelope of the inner fold edges. An envelope of the outer fold edges and the second support body section hug closely at least sectionwise an outer circumferential surface of the filter element.

A filter element has a preferably multilayer structure of a pleated filter medium (3) with a plurality of individual filter pleats (5, 7). Due to an alternating sequence of filter pleats (5) with a first pleat height (h1) and filter pleats (7) with a second pleat height (h2), more effective filter surfaces are available than with filter pleats with a uniform pleat height. Upon throughflow by a fluid to be filtered, a lower surface load for the filter medium (30 and lower passage speed of the fluid are present during filtration. A static loading of the filter medium (3) during operation of the filter is then reduced. A hydraulic circuit has such a filter element (1).