Filter cartridge and filter bag for a water filter device

Description

Area

[0001] The invention relates to a filter bag for a reusable filter cartridge for a water filter device, a filter cartridge and a water filter device. background

[0002] Filter cartridges for water filtration devices, especially countertop water filters, consist of a plastic housing filled with a filter medium. This filter medium is, for example, activated carbon and an ion exchange material in granular form. The filter medium removes or reduces particles and limescale from the raw water being filtered, thus improving the taste and odor of the filtered water. When the filtered water is used in machines and appliances such as coffee makers, limescale buildup is reduced.

[0003] The filter medium is consumed during the use of the water filter device and therefore needs to be replaced regularly, for example every 4-6 weeks. The filter material is usually replaced by replacing the entire filter cartridge, meaning the plastic housing of the filter cartridge is disposed of along with the filter material, even though the plastic housing is not subject to any wear or consumption during operation of the water filter device. This practice generates an unnecessarily large amount of plastic waste.

[0004] To avoid plastic waste, DE 9108688 U1 proposes a reusable filter cartridge with a two-part housing that can be opened to replace the used filter medium with new, unused filter granules. However, contamination can occur when removing the used granules, as they sometimes can only be removed from the filter cartridge housing by rinsing, thereby contaminating the outside of the cartridge and / or a sink.

[0005] DE 20 2019 003 368 U1 therefore proposes a reusable filter cartridge in which the granular filter medium is contained within a closed filter bag. The reusable filter cartridge can be opened, allowing the filter bag containing the used filter material to be easily and cleanly removed and replaced with a new filter bag containing unused filter material. This replacement process prevents contamination from the filter granules, which are completely enclosed within the filter bag. Furthermore, the additional material consumption of such a filter bag is limited to the bag itself, while the filter cartridge housing is reused. For installation in certain water filtration devices, the filter cartridge must have a substantially cylindrical indentation in the center of its base to allow it to fit into the inlet funnel of the respective water filtration device.Consequently, the proposed filter pocket is also provided with a corresponding indentation to fill the interior of the filter cartridge as completely as possible.

[0006] EP 2 583 731 A1 describes a filter cartridge with a cup-shaped base. The base has an arc-shaped inlet that provides a variable filter cross-section. The length of the inlet can be up to 80% of the total length of the base of the filter cartridge. The base is filled with filter material. The filter material is loose, granular filter material directly filled into the housing of the base.

[0007] Starting from this premise, it is an object of the present invention to create a filter cartridge or water filter device that is improved compared to the prior art. Description of the invention

[0008] According to a first aspect of the present invention, a filter cartridge for a water filter device with a filter bag is proposed. The filter cartridge is designed in two parts, with a lid removable from a lower housing part, and has an interior space for receiving a filter bag. The shape of the filter bag is adapted to the shape of the interior space of the filter cartridge. A side opposite the bottom of the filter bag has a sealing rim. The filter bag has an arc-shaped indentation in the bottom of the filter bag along a first cross-sectional line. The depth of the indentation is greatest in the center of the filter bag. Furthermore, a circumferential snap-on rim with a locking projection is provided on the underside of the lid, which engages a corresponding locking projection arranged on the lower housing part.In particular, the snap-on edge is elastically designed and creates a positive or force-fit connection between the lid and the lower housing part. A clamping strip is arranged on the underside of the lid, which in particular has a triangular cross-section, so that the sealing edge of the filter pocket is clamped between an end face of the lower housing part and the clamping strip. In practice, the filter cartridge designed according to the invention has the advantage of achieving high filtration performance or flow rate while simultaneously providing good filtration efficiency. This contrasts with the properties of conventional cartridges, where a high flow rate is usually accompanied by a comparatively poorer filtration efficiency.The sealing rim on the filter bag prevents unfiltered water from flowing past the filter bag and the filter medium contained within, which would adversely affect the filtering effect of the water filter device.

[0009] The lid is removable from the lower part of the filter cartridge housing, allowing for easy replacement of the filter bag.

[0010] The lid can be removed from the lower part of the housing many times to replace the filter bag, thus ensuring a long service life for the filter cartridge housing, which brings corresponding advantages in terms of waste prevention.

[0011] When the filter cartridge is assembled, the sealing edge of the filter pocket is clamped between an end face of the lower housing part and the clamping strip. The clamping strip ensures that the clamping force generated by the snap-on edge is converted into a high contact pressure on the sealing edge of the filter pocket, thereby achieving a good seal between the filter pocket or the sealing edge of the filter pocket and the lower housing part of the filter cartridge.

[0012] According to an advantageous embodiment, the arc-shaped inlet has a specific length, which is bounded on both sides by column-shaped sections. This design of the filter bag offers manufacturing advantages and results in particularly favorable flow conditions within the filter bag.

[0013] In a particularly preferred embodiment, the length of the arcuate indentation corresponds to 40-80% of the length of the first cross-sectional line, in particular 50-70%. The portion of the cross-sectional line not covered by the arcuate indentation is essentially occupied by the column-shaped sections, the dimensions of which are approximately equal along the first cross-sectional line.

[0014] In one embodiment, the filter pocket has a longitudinal side and a broad side adapted to the dimensions of the interior of the filter cartridge, wherein the broad side has a shorter length than the longitudinal side and the first cross-sectional line runs parallel to the longitudinal side or parallel to the broad side of the filter pocket. The intake thus extends along the longitudinal or broad side of the filter pocket, which has a favorable effect on the flow conditions within the filter pocket.

[0015] In another embodiment of the filter cartridge, the indentation of the filter pocket also extends in an arc along the second cross-sectional line. If the first cross-sectional line runs along the longitudinal side and the second cross-sectional line along the broad side of the filter pocket, or vice versa, then the indentation forms a cavity that essentially corresponds to an ellipsoidal segment.

[0016] The different designs of the filter inlet influence both the flow patterns within the filter bag and the volume of the filter bag itself. This design of the inlet within the filter bag thus offers possibilities for modifying the filter performance and effectiveness of a filter cartridge. In practice, this makes it possible to manufacture filter cartridges with different properties that have identical cartridge housings and differ only in the filter bag used within the cartridge. This concept offers cost advantages in warehousing and manufacturing the filter cartridge and provides a high degree of flexibility for the user, who can determine the filter cartridge's properties by selecting a suitable filter bag.

[0017] Advantageously, the filter bag is made of a textile material, particularly a non-woven fabric. This non-woven material is permeable to liquids, especially water. At the same time, it acts as a pre-filter upstream of the filter medium, trapping particles contained in the unfiltered raw water. Furthermore, the non-woven material prevents the granular filter medium from escaping the filter bag. The non-woven material can be made of a suitable plastic.

[0018] It has proven advantageous to design the filter bag with a lower section that is sealed with a cover fleece. This design of the filter bag offers manufacturing advantages.

[0019] Advantageously, the cover fleece is bonded to the bottom of the bag in a fabric-like manner, in particular by sealing, welding or gluing.

[0020] Finally, a water filter device with a filter cartridge according to the first aspect of the invention is proposed, based on a second aspect. The water filter device according to the invention realizes all the advantages already described in connection with the filter cartridge according to the invention. Brief description of the drawing

[0021] The invention is explained in more detail below using one embodiment as an example, with reference to the accompanying figures. All figures are purely schematic and not to scale. They show: Fig. 1 a filter device in the shape of a water jug ​​in a perspective view; Fig. 2 a perspective view of a filter cartridge obliquely from above; Fig. 3 the filter cartridge made of Figure 2 with lid removed; Fig. 4A a filter bag that is inside the filter cartridge made of Figure 2 taken in a view obliquely from above; Fig. 4 Longitudinal section through the filter pocket made of Figure 4A; Fig. 4C the filter bag made of Figure 4A in a view obliquely from below; and Fig. 5 a cross-section through an edge of the cartridge made of Figure 2 .

[0022] Identical or similar elements in the figures are marked with the same or similar reference symbols. Example of implementation

[0023] Figure 1Figure 1 shows a perspective side view of an embodiment of a device 100 for filtering liquids. In the illustrated embodiment, the device 100 is designed as a table water jug ​​and has a collection vessel 101 for receiving filtered water. A handle 102 is arranged on the collection vessel 101 for handling. Furthermore, the collection vessel 101 has a pouring spout 103 at its upper edge. When using the device, a user can grasp the collection vessel 101 by the handle 102 and pour filtered water, for example, into a glass (not shown) via the pouring spout 103. An open-topped inlet funnel 104 is inserted into the collection vessel 101, which has a receiving chamber 106 in its lower region for a filter cartridge 200 ( Figure 2The inlet funnel 104 has a circumferential flange 107 at its upper edge, which rests on an edge of the collection vessel 101, so that the inlet funnel 104 is held in the collection vessel 101. A base 108 of the inlet funnel 104 is located at a distance H from a base 109 of the collection vessel 101. The base 108 of the inlet funnel 104 has one or more outlet openings from which filtered water flows from the inlet funnel 104 into the collection vessel 101. The inlet funnel 104 is closed on its upper side with a removable cover 111, which prevents dust or dirt particles from falling into the inlet funnel 104 during use of the filter device 100.

[0024] In Figure 2Figure 1 shows a schematic perspective view obliquely from above of a filter cartridge 200. A housing top or lid 201 forms the upper surface of the filter cartridge 200, which sits on a cup-shaped housing bottom 202. The lid 201 and the housing bottom 202 together form a housing of the filter cartridge 200, which as a whole is designated by the reference numeral 203. Filter material is contained within the housing 203 of the filter cartridge. The filter material is, for example, in the form of filter granules, which are in a Figure 2The filter cartridge 200 is contained within a concealed filter bag. Various filter materials can be used to remove unwanted substances, ions, and / or particles from the water. The lid 201 has multiple inlet openings 204 through which unfiltered liquid, especially water, flows into the interior of the filter cartridge 200. A handle 206 allows the filter cartridge 200 to be grasped and pulled out of the receiving chamber 106 of the inlet funnel 104 for possible replacement. A sealing rim 207 is visible at the upper edge of the lower housing part 201.

[0025] The lower housing section has an essentially oval shape, measuring, for example, 70-80 mm in length and 40-50 mm in width. The upper housing section 201 is removable from the lower housing section 202, thus providing access to the interior of the filter cartridge 200.

[0026] In Figure 3 Is the filter cartridge 200 made of Figure 2The cover 201 is shown with the lid 201 removed. The lid 201 has a circumferential flange 301 to which the sealing edge 207 is integrally formed. The connection between the lid 201 and the lower housing part 202 is made by a snap-fit ​​connection, which is described further below in connection with Figure 5 The snap connection can be released by a user by holding the lower housing part 202 and pulling on the handle part 206. Once the upper housing part 201 is in place, the interior of the filter cartridge 200 is accessible, where, in a functioning filter cartridge 200, a filter bag filled with filter granules is located. The lower housing part 202 has a circumferential lateral boundary wall 303 and a cartridge base 302 on the side opposite the cover 201.

[0027] In Figure 4AFigure 400 shows a filter bag 400 in a top-down oblique view. The filter bag 400 has a flat cover fleece 401, which closes a substantially cup-shaped bag base 402. The filter bag 400 contains the filter granules mentioned above. The bag base 402, like the cover fleece 401, is made of a fine-pored nonwoven material that is permeable to liquids, especially water, and securely encloses the filter granules. The cover fleece 401 also acts as a mechanical filter, retaining particulate impurities that may be present in the raw water. In other embodiments, woven, knitted, or crocheted structures, especially flat textile structures, can be used instead of a nonwoven material. Combinations of different materials are also possible.

[0028] The shape and dimensions of the filter pocket 400 correspond to the interior of the filter cartridge 200. The filter pocket therefore has an oval shape in a horizontal cross-sectional plane, corresponding to the shape of the lower housing part 202 and essentially filling the interior of the filter cartridge. On its narrow sides, the filter pocket 400 has column-shaped sections 403, which are connected to each other by an arcuate indentation 404. The undersides of the column-shaped sections 403 and the arcuate indentation 404 form the base of the filter pocket 400, or the lower part of the pocket.

[0029] The lower part of the pocket 402 has a circumferential horizontal flange 406 onto which the cover fleece 401 is sealed. In other embodiments, the connection between the lower part of the pocket 402 and the cover fleece 401 is made by gluing, welding, or other suitable joining techniques. The horizontal flange 406, together with the sealed area of ​​the cover fleece 401, forms a sealing edge 407, which is also visible in an enlarged section in Figure 4A The enlarged section shows a small gap for better differentiation between the horizontal flange 406 and the cover fleece 401; this gap does not actually exist. The dashed line 408 denotes a first cross-sectional line and the dashed line 409 a second cross-sectional line.

[0030] Figure 4B shows a cross-section through the filter pocket 400 along the cutting plane BB, which runs along the in Figure 4AThe first cross-sectional line 408 shown runs along this line. In this illustration, the circumferential sealing edge 407 and the indentation 404 are clearly visible. In particular, it is easy to see that the indentation 404 arches towards the cover fleece 401 like a Romanesque arch with a crown height h. The crown height h corresponds to a depth of the indentation 404. The span of the indentation or arch 404 is I.

[0031] Finally, it shows Figure 4C A view of the filter pocket from an angle below.

[0032] The relative size ratios of the filter bag 400, as seen in the Figures 4A to 4C The illustrations are only examples and may differ in other embodiments. In particular, the arch 404 may have a greater or lesser height h and / or a greater or lesser span I.

[0033] In the Figures 4A to 4CThe arch extends along the longer side of the oval filter pocket 400, while the indentation follows a straight line parallel to the shorter side of the oval filter pocket 400. The indentation 404 thus has a shape similar to a Romanesque bridge arch.

[0034] In a modified embodiment, the arc curves along the shorter side of the oval filter pocket 400, while the inlet follows a straight line parallel to the longer side of the oval filter pocket 400. Finally, in a further embodiment, the inlet 404 extends in an arc shape along both the longitudinal and transverse directions of the filter pocket 400, so that the inlet assumes a shape similar to an ellipsoidal segment.

[0035] Figure 5 shows a cross-section through the edge of the filter cartridge made of Figure 2This illustration shows a circumferential snap-on edge 501 extending downwards from the flange 301. On its radially inner side, the snap-on edge 501 has a detent projection 502. When the cover 201 is fitted, the detent projection 502 engages a detent projection 503, which is integrally formed on the upper edge of the lower housing part 202. The detent projection 503 is located on the outside of the lower housing part 202. When the cover 201 is fitted onto the lower housing part 202, the snap-on edge 501 and / or the lower housing part 202 deform elastically, causing the detent projections 502 and 503 to slide past each other. Once the locking projections 502, 503 have passed each other, the snap edge 501 and / or the lower housing part 202 return to their original shape and establish a positive or force-fit connection between the lower housing part 202 and the cover 201.

[0036] When the filter bag 400 is inserted into the lower housing part 202 of the filter cartridge, the sealing rim 407 rests on an end face 504 of the cup-shaped lower housing part 202 and is clamped between the end face 504 of the lower housing part 202 and a circumferential clamping strip 506 located on the underside of the cover 201 when the upper housing part is placed on the lower housing part 202. The clamping strip 506 runs parallel to the snap-on rim 501, which thus generates a uniform contact pressure of the clamping strip 506 on the sealing rim 407. The clamping strip 506 has a triangular cross-section, the apex of which points towards the sealing rim 407. The clamping force of the snap-on edge 501 thereby generates the greatest possible contact pressure along the clamping strip 506 in order to achieve a good seal of the sealing edge 407 and thus of the filter pocket 400 against the lower part of the housing 202.Unfiltered water flowing into the filter cartridge through the inlet openings 204 cannot therefore flow past the filter bag 400, but only through the filter bag 400, whereby the water comes into contact with the filter granules and is filtered.

[0037] Snap connections of various designs are known in the prior art. As an alternative to the one described in Figure 5 The snap connection shown can, for example, also include locking hooks that engage in corresponding locking openings on the upper housing part 201 or the lower housing part 202.

[0038] In practice, it has been shown that filter cartridges equipped with a filter bag according to the invention exhibit a high filtration performance and flow rate compared to conventional filter cartridges, while still achieving good filtration efficiency. Experience has shown that a high flow rate leads to reduced filtration efficiency, and vice versa. This relationship does not appear to apply to the proposed filter bag. The indentation on the underside of the filter bag seems to have a beneficial effect on the water flow within the filter cartridge, thus achieving the described advantage of a high flow rate combined with good filtration efficiency. Here, filtration efficiency refers in particular to the removal of particles and unwanted substances, as well as the exchange of ions.

[0039] By selecting the fleece material for the filter bag and shaping the feed 404, filter bags or filter cartridges with different properties in terms of flow rate and filter effect can be produced. Reference symbol list

[0040] 100 Filter device 400 Filter bag 101 Collection container 401 Cover fleece 102 Handle 402 Bag bottom 103 Pouring spout 403 Columnar section 104 Inlet funnel 404 Arch, indentation 106 Admissions chamber 406 flange 107 circumferential flange 407 Sealing edge 108 Inlet funnel bottom 408 first cross-sectional line 109 bottom of vessel 409 second cross-sectional line 111 Lid 501 Snap edge 502,503 Rast ledge 200 Filter cartridge 504 Front 201 upper housing part 506 Terminal block Lid 202 Lower housing part 203 The housing as a whole 204 Inlet openings 206 handle part 207 Sealing edge 301 circumferential flange 302 Cartridge base 303 Side boundary wall

Claims

1. A filter cartridge for a water filter device with a filter bag (400), wherein the filter cartridge (200) is formed in two pieces and has a lower housing part (202) and a cover (201), which can be removed from the lower housing part, as well as an interior space for receiving a filter bag (400), characterized in that the form of the filter bag is adapted to the shape of the interior space of the filter cartridge (200), that a side lying opposite a bottom of the filter bag has a sealing edge (407), that the filter bag has a curved feeder (404) in the bottom of the filter bag along a first cross-sectional line, wherein the depth (h) of the feeder (404) is largest in the center of the filter bag, that a circumferential snap-on edge (501) with a latching projection (502), which engages over a corresponding latching projection (503) arranged on the bottom housing part (202), is provided on an underside of the cover (201), wherein in particular the snap-on edge (501) is formed elastically and establishes a positive or non-positive connection, respectively, between the cover (201) and the lower housing part (202); and that a clamping strip (506), which in particular has a triangular cross section, is arranged on the underside of the cover (201), so that the sealing edge of the filter bag is clamped between a front side of the lower housing part and the clamping strip.

2. The filter cartridge according to claim 1, characterized in that the curved feeder (404) has a certain length (I), which is delimited on both sides by column-shaped sections (403).

3. The filter cartridge according to claim 2, characterized in that the length of the curved feeder corresponds to 40-80% of the length of the first cross-sectional line, in particular to 50-70%.

4. The filter cartridge according to claim 1, characterized in that the filter bag (400) has a longitudinal side and broad side, which are adapted to the dimensions of the interior space of the filter cartridge (200), wherein the broad side has a smaller length than the longitudinal side and that the first cross-sectional line runs parallel to the longitudinal side or parallel to the broad side of the filter bag (400).

5. The filter cartridge according to any one of the preceding claims, characterized in that the feeder (404) extends along a second cross-sectional line, which runs perpendicular to the first cross-sectional line, and follows a straight line.

6. The filter cartridge according to any one of the preceding claims, characterized in that the feeder (404) describes a second curve along a second cross-sectional line, which runs perpendicular to the first cross-sectional line.

7. The filter cartridge according to any one of the preceding claims, characterized in that the filter bag (400) is made of a textile material, in particular a nonwoven material.

8. The filter cartridge according to any one of the preceding claims, characterized in that the filter bag (400) has a lower bag part (402), which is closed with a covering nonwoven (401), wherein the covering nonwoven (401) is connected to the lower bag part (402), in particular by means of a substance-to-substance bond, in particular sealed on, welded or adhered.

9. A water filter device with a filter cartridge according to any one of the preceding claims.