Filter cartridge and filter unit with this filter cartridge

Abstract

Filter cartridge with: a filter element (2) for installation in a filter unit (100), wherein the filter unit (100) is of the type having a filter bowl (31) and a filter head (36) characterized by a filter cage (3) designed to accommodate the filter element (2).

Description

The invention relates to a filter cartridge according to the preamble of claim 1 and to a filter unit comprising this filter cartridge.Filter units according to the preamble of claim 1 are known, for example, from EP 2 300 123 A1, EP 2 789 375 A1 or EP 3 651 873 A1. All of these units comprise a filter element for installation in a filter pot of a filter unit. The filter elements are replaceable with respect to the filter pot.The aforementioned filter units, in particular the filter elements of the aforementioned filter units, are susceptible to deformation when handled incorrectly. Another disadvantage is that a filter medium, in particular a paper filter medium, tends to be contaminated with dirt and dust, for example by contact with the hands of a mechanic or by other environmental conditions in a workshop before the filter element is inserted into the filter pot.Accordingly, there is a need for an improved filter cartridge design for a corresponding filter unit.The above described problems are solved by a filter cartridge according to the invention, comprising:a filter element for installation in a filter unit, said filter unit being of the type,which has a filter shell and a filter head, anda filter cage for receiving the filter element.By providing a protective basket around the filter element, the deformation and / or contamination of the filter element, in particular of a paper filter element, is minimized or at least reduced.In a preferred embodiment, the filter cage comprises a plurality of connecting lugs, each configured to cooperate with corresponding connecting ribs of the filter container, and the connecting ribs and the connecting lugs can provide, in an engagement position, a fixation of the filter cage relative to the filter container in an axial direction and along a first rotational direction.In this embodiment, it is possible to use the filter cage also as a connecting element between the filter cartridge and the filter pot of a corresponding filter unit.In a preferred embodiment, the filter cage further comprises at least one spring element configured to be biased in a radially inward direction relative to the filter cage during attachment of the filter cage to the filter pot, and further configured to snap radially outward and enter a slot of the filter pot, thereby blocking movement of the filter cage and the filter pot along a second rotational direction opposite the first rotational direction.With such an embodiment, a complete fixing along all degrees of freedom relative to the filter pot is achieved in only one part.According to a further embodiment of the invention, the filter cage has a base section in the axial direction, and the filter cage has a receiving section at an axial distance from the base section for receiving an end cap.This embodiment provides a defined and precise positioning of the filter element relative to the filter basket. Moreover, an upper end cap can be easily mounted, e.g. glued onto the filter cage.According to a further embodiment of the invention, the spring element is a rod-shaped flexible spring element and has a radially outwardly projecting protrusion at one free end and is connected at its other end to the filter cage.This embodiment offers a simple solution for the provision of the spring element as part of a one-piece injection molded part made of plastic. Due to the elasticity of a resin, e.g. a thermoplastic resin, the spring forces required to provide the locking functions of the spring element can easily be achieved.According to a further embodiment of the invention, the rod-shaped bending spring element extends along a circumferential direction relative to the filter element.In this orientation and installation position of the rod-shaped flexible spring element, stretching forces within the rod-shaped spring element predominantly act on the spring element during a rotating installation movement of the filter cage relative to the filter pot. The bending forces are minimized.According to a further embodiment of the invention, the filter cage has a net-like cage wall which comprises a rod structure comprising a plurality of rods and openings between adjacent rods.With this construction, an appropriate protection function of the filter element is ensured with a minimum use of raw material and thus an effective use of material.According to a further embodiment of the invention, the filter cage comprises a hydrophobic treatment attached to the filter cage, which in particular closes the openings and thereby separates water from the fuel.According to a further embodiment of the invention, at least some of the rods expand in a direction inclined to the axial direction.With this measurement, the filter basket obtains adequate strength against rotational deformation because the oblique rods are able to absorb and support the rotational reaction forces that may occur during mounting of the filter basket relative to the filter pot.According to a further embodiment of the invention, the filter cage has a multiplicity of regularly inwardly projecting ribs which are designed to guide the filter element in the axial direction during assembly.With this measurement, rotational fixation of the filter element relative to the filter cage can be easily achieved.According to a further embodiment of the invention, the connecting lugs of the filter cage and the corresponding connecting ribs of the filter pot form a rotatable bayonet lock.A rotatable bayonet closure is a very simple way of fastening the filter basket together with the filter element to the filter pot.According to a further embodiment of the invention, the surfaces of the connecting straps of the filter basket and of the connecting ribs are flush with one another and thus form a contact surface for second connecting ribs which are fastened to the filter head.This creates a composite connecting rib in a particularly simple manner, which can be used for locking into a mating connection of the filter head.According to a further embodiment of the invention, both the filter basket and the end cap carry markings which represent a suitable position with respect to one another in the circumferential direction.This facilitates checking the correct mounting of the filter element relative to the filter cup by a visual indicator.Furthermore, the problems of the filter unit are solved by a filter unit with a filter cartridge according to the invention.The invention will be described in more detail with reference to the following figures: FIG. 1 is an isometric view of a filter cartridge of the present invention; FIG. 2 is an isometric view of the filter cartridge of FIG. 1 without an end cap; FIG. 3 is an isometric view of the filter cage of the filter cartridge of FIG. 1 ; FIG. 4 is an isometric view of the filter cartridge of FIG. 1 inserted into a filter canister of a filter unit; FIG. 5 : longitudinal section along a central axis of a filter unit according to the invention with a filter cartridge according to the invention;A filter cartridge 1 according to the present invention will be described with reference to Figs. 1 to 3.The filter cartridge 1 has a filter element 2 which is, for example, a paper filter element. The filter element 2 is accommodated by a filter cage 3. The filter cage 3 has a cage wall 4 which surrounds the filter element 2 circumferentially. At an upper end of the filter cage 3, distributed along a circumferential direction 5, the filter cage 3 has a plurality of connecting attachments 6, in particular three connecting attachments 6.The cage wall 4 consists of a rod structure consisting of a plurality of rods 7A and openings 8. In addition to the rods 7A which are oriented in their longitudinal direction parallel to a central axis 9 of the filter cartridge 1, there are encircling rods 7B which extend in their longitudinal direction in the circumferential direction 5. Furthermore, there are inclined rods 7C whose longitudinal extension is inclined at a distance relative to the central axis 9.The rods 7A, 7A, 7B delimit the openings 8 surrounded by the rods 7A, 7B, 7C, which openings are open in one variant. In a second alternative, these openings 8 are closed by a hydrophobic layer 7D. The hydrophobicizing 7D is a hydrophobic fabric printed on the filter cage 3 and filling the openings 8 between the rods 7 to separate water from the fuel.Viewed in the vertical direction V, the filter cartridge comprises a bottom portion 10 at a vertical lower end. Opposite the bottom portion 10 at a vertical upper end, the filter cartridge 1 comprises an end cap 11 fixed to an upper end of the filter cage 3. The end cap 11 can be fastened to the filter cage 3, for example, by adhesive bonding. In the region of the vertical upper end, approximately in the same vertical position in which the connection closures are located, a spring element 15 is provided, which is designed as a rod-shaped spring element 15. The spring element 15 has a free end 16 which carries a locking projection 17, wherein the locking projection 17 protrudes slightly outwards from a rod element 18 of the rod-shaped spring element 15. A second end 19 of the rod-shaped spring element 15 connects the latter in one piece, for example as an injection molded part, to the filter cage 3.The connecting shoulders 6 each have a hook section 20 which is open in the clockwise direction toward the circumferential direction 5. The hook portions 20 are intended to engage with corresponding connecting ribs 30 and form a mating connecting element which is part of a filter pot 31 of a filter unit 100 according to the invention (see FIGS. 4 and 5 ). As a result, the connecting shoulders 6 of the filter cage 3 and the corresponding connecting ribs 30 of the filter pot 31 form a first rotatable bayonet lock which is capable of connecting the filter cartridge 1 to the filter pot 31.Further, the connecting bosses 6 of the filter cage 3 have an inclined lower surface, a switch, and an engaging state of the filter cartridge 1 seated in the filter pot 31 is flush with a lower surface 32 of the respective connecting ribs 30, thereby forming a downward ramp, such as a vertically descending combined surface 33 as viewed clockwise in the circumferential direction, forming an engaging surface for respective second connecting ribs 35 of a filter head 36 of the filter unit 100. The combined surfaces 33, together with the second connecting ribs 35, form a second rotary bayonet closure between the filter head 36 and the filter pot 31.On an inner side of the cage wall 4, in particular along the vertical rods 7A of the cage wall 4, a plurality of vertical ribs 40 are provided, which contribute to stiffening the filter cage 3 against buckling in the vertical direction and can also serve as guide rails when the filter element 2 is inserted into the filter cage 3.Both the end cap 11 and the cage wall 4 carry optical markings 50, such as arrows, which, when pointing towards one another, indicate a filter cage 3 in the sacrum further in the circumferential direction 5.List of reference characters1 Filter cartridge 2 Filter element 3 Filter cage 4 Cage wall 5 Circumferential direction 6 Connecting shoulders 6A Oblique surface 7 Rods 7A Vertical rods 7B Circumferential rods 7C Inclined rods 7D Hydrophobicization 8 Openings 9 Central axis 10 Base portion 11 End cap 15 Spring element 16 Free end 17 Locking projection 18 Rod element 19 Second end 20 Hook portion 30 Connecting ribs 31 Filter pot 32 Lower surface 33 Combined surface 35 Second connecting ribs 36 Filter head 40 Vertical ribs 50 Markings 100 Filter unitReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedEP 2 300 123 A1

[0002] EP 2 789 375 A1

[0002] EP 3 651 873 A1

[0002]

Claims

A filter cartridge comprising: a filter element (2) for incorporation into a filter unit (100), the filter unit (100) being of the type comprising a filter cup (31) and a filter head (36), characterised by a filter cage (3) configured to receive the filter element (2).Filter cartridge according to claim 1, characterized in that the filter cage (3) comprises a plurality of connection bosses (6) each configured to cooperate with corresponding connection ribs (30) of the filter pot (31), and that the connection ribs (30) and the connection bosses (6) in an engagement position can provide a fixation of the filter cage (3) relative to the filter pot (31) in an axial direction and along a first rotational direction.The filter cartridge according to claim 1 or 2, characterized in that the filter cage (3) further comprises at least one spring element (15) configured to be biased in a radially inward direction relative to the filter cage (3) during attachment of the filter cage (3) to the filter pot (31), and may be further configured to snap radially outward into a slot of the filter pot (31), thereby blocking movement of the filter cage (3) and the filter pot (31) along a second rotational direction opposite to the first rotational direction.Filter cartridge according to claim 1, characterised in that the filter cage (3) has a base section (10) in the axial direction and a receiving section for receiving an end cap (11) at an axial distance from the base section (10).Filter cartridge according to one of the preceding claims, characterized in that the spring element (15) is a rod-shaped flexible spring element (15) and has a radially outwardly projecting projection at a free end (16) and is fastened at its other end to the filter cage (3).Filter cartridge according to one of the preceding claims, characterized in that the rod-shaped bending spring element (15) extends along a circumferential direction (5) relative to the filter element (2).Filter cartridge according to one of the preceding claims, characterized in that the filter cage (3) has a net-like cage wall (4) with a rod structure comprising a plurality of rods (7A, 7B, 7C) and openings between adjacent rods (7A, 7B, 7C).Filter cartridge according to one of the preceding claims, characterized in that the filter cage (3) has a hydrophobic treatment (7D) applied to the filter cage (3).A filter cartridge according to any preceding claim, characterised in that at least some of the rods (7A, 7B, 7C) extend in an oblique direction relative to the axial direction.Filter cartridge according to one of the preceding claims, characterized in that the filter cage (3) has a multiplicity of regularly inwardly projecting ribs (40) which are designed for guiding the filter element (2) in the axial direction during assembly.Filter cartridge according to one of the preceding claims, characterized in that the connecting locks of the filter cage (3) and the corresponding connecting ribs (30) of the filter pot (31) form a rotatable bayonet lock.Filter cartridge according to any of the preceding claims, characterized in that the undersides of the connecting locks and the connecting ribs are flush and form an abutment surface for second connecting ribs (35) which are fastened to the filter head (36).Filter cartridge according to any of the preceding claims, characterized in that both the filter cage (3) and the end cap (11) carry markings (50) which represent a suitable position with respect to one another in a circumferential direction (5).Filter unit (100) comprising a filter cartridge (1) according to any one of the preceding claims.

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