Filter screen, tubular filter and filter device

Abstract

A filter screen (4) for a tubular filter (2) for filtering liquids, particularly polymer melts (24), wherein the tubular filter screen (4), formed by bending a flat screen blank (19), has: a filter axis (3); a screen wall (11) and a perforated region (13) on the circumference of the screen wall (11) having densely arranged, fine through holes (14); and a connecting portion (17) oriented in the axial direction. The perforated region has a region edge (15) extending in the axial direction at both ends along the circumferential direction, wherein the region edge terminates at a distance in front of the connecting portion when forming a spacer region (18), and at least one region edge has a contour geometry (16) in its axial direction, which has varying edge distances (a1, a2) relative to the adjacent connecting portion, wherein the contour geometry (16) has a contour depth (t) in the circumferential direction, which is a multiple of the diameter of the through hole (14). The invention relates to a filter screen (4) for a tubular filter (2) for filtering liquids, in particular polymer melts (24), wherein the tubular filter screen (4), which is bent from a flat screen blank (19),has a filter axis (3), a screen wall (11) and, on the circumference of the screen wall (11), a perforation region (13) with densely packed, fine through openings (14) and a connecting means (17), which is aligned with an axial direction component, in particular in the form of a weld seam. The perforation region (13) has, at each of its two ends in the circumferential direction, a region edge (15) extending with an axial direction component, the region edges (15) each ending at a distance in front of the connecting means (17) so as to form a spacer region (18), and at least one region edge (15) in its axial profile having a profile geometry (16) with varying edge distances (a1,a2) from the adjacent connecting means (17).The profile geometry (16), as viewed in the circumferential direction, has a profile depth (t) which is a multiple of the diameters of the through openings (14).

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