Abstract: A filter device having a filter housing (1), in which a replaceable filter element (7) is accommodated and which has a cover part (2), wherein the element material (9) of the filter element (7) extends between two end caps (13, 14) of the latter, is characterized in that the filter housing (1), which is formed as an outlet pipe (3), extends between both end caps (13, 14) as well.

Abstract: 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).

Abstract: A filter element (1) has an inner body (12) and an outer body (11). One casing body (12) has a cross section deviating from circularity. Body contact surfaces (20, 21) face one another for the contact of essentially all filter folds (18a-18f, 18I-18III) of a pleated filter web (10). The filter folds (18a-18f, 18I-18III), in terms of fold height (h), are divided into individual groups (I, II) each having several filter folds (18I-18II) of a common fold height (hmax, hmin) alongside one another in sections. Between two adjacent filter folds (18a-18f, 18I-18III) of different groups (I, II) filter folds are arranged (18b-18e; 18m) of at least one third group (III).

Abstract: A filter element with a preferably multilayer structure of a pleated filter medium (3) with a plurality of individual filter pleats (5, 7) is characterised in that, 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, and therefore, upon throughflow by a fluid to be filtered, there is a lower surface load for the filter medium (3) and lower passage speed of the fluid during filtration, with the consequence that a static loading of the filter medium (3) during operation of the filter is reduced. The invention also relates to a hydraulic circuit with such a filter element (1).

Abstract: A filter element (1) having at least one inner (12) and an outer casing body (11), of which at least one casing body (12) has a cross section deviating from circularity and which have contact surfaces (20, 21) facing one another for the contact of essentially all filter folds (18a-18f, 18I-18II) of a pleated filter web (10), the filter folds (18a-18f, 18I-18II), in terms of fold height (h), being divided into individual groups (I, II) each having several filter folds (18I, 18II) of a common fold height (hmax, hmin) alongside one another in sections, is characterized in that between two adjacent filter folds (18a-18f, 18I-18II) of different groups (I, II) are arranged filter folds (18b-18e; 18m) of at least one further third group (Ill), the filter folds (18b-18e, 18m) assigned to the third group (III), in the manner of step formation, have a common fold height (ho) which is different from the respective fold height (hmax, hmin) of the filter folds (18I, 18II) of the two adjacent neighbouring groups (I, II), a