DE102019215060B3 - Liquid filter and tank filter system with a liquid filter - Google Patents

Abstract

The invention relates to a liquid filter (1) for separating particles from a liquid, in particular from fuel or a urea solution. The liquid filter (1) has a first filter medium (10), a second filter medium (20) and a support frame (2) with a support frame wall (3). The support frame wall (3) has a first end face (4) pointing along a z-direction and a second end face (5) facing away from the first end face (4), the first filter medium (10) on the first end face (4 ) is fastened in a fluid-tight manner, the second filter medium (20) being fastened in a fluid-tight manner on the second end face (5), the support frame (2), the first filter medium (10) and the second filter medium (20) enclosing an interior space (7), wherein the liquid filter (1) is surrounded by an external environment (9). It is provided that the support frame (2) has at least one pocket (6) which extends into the interior space (7), the support frame (2) having at least one pocket (6) which extends into the interior space (7 ).

Description

Field of invention

The invention relates to a liquid filter for separating particles from a liquid, in particular from fuel or a urea solution. The invention further relates to the use of such a liquid filter in a tank filter system.

State of the art

So-called tank filter systems are known from the prior art, e.g. for motor vehicles. In such tank filter systems, a liquid filter is often arranged very close to the bottom of a tank for the liquid to be cleaned in order to be able to pass liquid from the tank through the liquid filter and feed it to a consumer in every driving situation, even when the tank is almost empty. The liquid to be cleaned can be, for example, fuel such as diesel or gasoline or a urea solution in an SCR system (selective catalytic reduction). Such SCR systems are used, for example, to reduce the amount of stick oxide in the exhaust gas from internal combustion engines. By arranging the liquid filter directly in the liquid tank, valuable space can be saved, for example in motor vehicles.

Such a tank filter system with a liquid filter is for example from the DE 10 2017 212 826 A1 known.

From the DE 10 2017 212 768 A1 a liquid filter and a tank filter system with a liquid filter are known. In this case, a pocket-shaped filter element is arranged in an interior of the liquid filter, which is completely closed off from the interior by means of a filter medium along one side, so that liquid can flow from an exterior of the liquid filter into the filter element arranged in the interior and is cleaned after flowing through its filter medium can enter the interior.

Disclosure of the invention

The invention is based on the knowledge that, for such tank filter systems or liquid filters in such tank filter systems, several parameters should be optimized at the same time as possible. On the one hand, the filter surface should be as large as possible, so that the longest possible service life is achieved until the liquid filter needs to be replaced. In other words, the filter surface should be designed to separate as many particles as possible from the liquid to be cleaned before a filter medium of the liquid filter clogs or is covered with particles in such a way that there is an unacceptable pressure drop between a raw side (e.g. an outside) of the liquid filter and a clean side (eg an interior) of the liquid filter comes. Furthermore, the production costs for such a liquid filter should be as low as possible. This is preferably brought about by a production process that is as simple and accelerated or quick as possible. Furthermore, the liquid filter should meet all these parameters with the smallest possible space requirement, since, for example, the space available for such liquid filters in motor vehicles is limited. Finally, in such tank filter systems, a heating element is often provided in order to prevent the liquid from freezing or gelling. The heating element can be at a height of a few centimeters above the bottom of the tank in order to enable the liquid in the tank to be heated as well and evenly as possible.

Furthermore, on the one hand, the liquid filter with at least one filter medium through which the liquid to be cleaned is to pass should be arranged as close as possible to the bottom of the tank in order to be able to conduct liquid through the filter even when the tank is almost empty. At the same time, at least one section of the liquid filter should be arranged as close as possible to the heating element in order to ensure that the frozen or gelled liquid in the liquid filter is also heated and liquefied as quickly as possible after the heater is started. These boundary parameters can result in the liquid filter having a relatively large extension (height) in the direction from the bottom to the heating element and thus the interior occupying a large volume, which is ultimately not necessary for the filtration and the filter capacity.

It has been shown that with conventional liquid filters for tank filter systems, a large interior volume can be problematic when the liquid filter is first started up. Because in this case, the interior is either initially filled with air, which has to be pumped out completely by a pumping process so that the liquid filter can be operated without problems and with the highest efficiency. This is often difficult to achieve. Alternatively, the liquid filter can be filled or at least wetted with a special liquid (a so-called "epilamization liquid") during installation, which changes the surface tension in such a way that the air enclosed in the interior can escape through the filter medium.

However, this is costly and requires further handling steps in the manufacture of the liquid filter or in the installation.

There may therefore be a need to provide a liquid filter for use in a tank filter system, which has a high filtration capacity, which can be installed with at least one filter medium close to a bottom of the tank and which at the same time has at least a portion close to one of the bottom of the Tanks can be arranged by a few centimeters spaced heating element. Furthermore, the air located in the interior of the liquid filter should be able to be removed as completely as possible by simply pumping out during initial start-up without the use of epilamizing agents. Finally, the liquid filter should be as simple and inexpensive as possible to manufacture.

Advantages of the invention

This need can be met by the subject matter of the present invention according to the independent claims. Advantageous embodiments of the present invention are described in the dependent claims.

According to a first aspect of the invention, a liquid filter for separating particles from a liquid is proposed. The liquid can for example be a fuel or a urea solution.

The liquid filter has a first filter medium, a second filter medium and a support frame with a support frame wall. The support frame wall has a first end face which points along a z-direction. The support frame wall has a second end face facing away from the first end face. The first filter medium is fastened in a fluid-tight manner on the first end face and the second filter medium is fastened in a fluid-tight manner on the second end face. The support frame, the first filter medium and the second filter medium enclose an interior space, the liquid filter being surrounded by an external environment, the support frame having at least one pocket which extends into the interior space.

This advantageously has the effect that the liquid filter on the one hand has a high filtration capacity, since two filter media are provided. The liquid to be filtered can pass both through the first filter medium and through the second filter medium from the external environment into the interior of the liquid filter and is cleaned in this way. At the same time, the at least one pocket provided in the support frame can advantageously reduce the volume of the interior space, so that air located in the interior space can advantageously be completely removed particularly easily and reliably when the liquid filter is first started up. In this way, it can advantageously also be achieved that, for example, the first filter medium can be arranged particularly close to a bottom of the tank, while the second filter medium is clearly spaced along the z-direction, for example several centimeters, from the first filter medium in the vicinity of a heating element can be. In other words: the functionality of the liquid filter is ensured, the at least one pocket protruding into the interior advantageously reducing the volume of the interior. Because the pocket is arranged on the support frame, this volume reduction can be achieved particularly easily. For example, the support frame can be an injection molded part and have at least one pocket. It can for example be made in one piece. The term “one-piece element” is to be understood here to mean that such an element cannot be dismantled without being destroyed.

In the context of this application, the term “having” is used synonymously with the term “comprising”, unless otherwise described.

According to the invention, it is provided that the pocket does not allow any connection from the exterior of the liquid filter or the exterior of the liquid filter to the interior.

The pocket can have an opening on one side. However, it can also be designed to be completely closed. In this case, it can enclose a cavity.

The advantage of forming a pocket in comparison with completely filling the cavity enclosed by the pocket with the material of the support frame wall is that in this way material of the support frame can be saved. In addition, if a plastic material is used as the support frame wall material, it is advantageous that the support frame does not warp so easily. Because by forming a pocket, the wall stiffeners of the support frame can be of approximately the same thickness everywhere.

The liquid filter, viewed along the z-direction, can have a distance between the two filter media of, for example, at least 1 cm, preferably at least 3 cm, particularly preferably at least 5 cm and very particularly preferably at least 10 cm. The liquid filter can have a distance of at most 20 cm between the two filter media, viewed along the z-direction. For example, the distance is between the two filter media 20mm or 30mm, i.e. 2cm or 3cm.

The at least one pocket can have a height of, for example, 2 mm to 30 mm in the z direction. For example, it has a height of 4 mm or 5 mm or 7 mm. For example, it can have a height which is between 20% and 70% of the distance between the first and the second filter medium along the z-direction.

The fact that the at least one pocket is open to the external environment of the liquid filter has the advantageous effect that the holding capacity of the tank for the liquid to be filtered is not unnecessarily reduced. In other words: the volume saved in the interior of the liquid filter is now available as an additional volume in the external environment. This makes efficient use of valuable space.

The fact that the at least one pocket in the support frame is formed between the first face and the second face, viewed in the z-direction, has the advantageous effect that the pockets with their pocket walls do not reduce the effective available filtration surface of the first filter medium and the second filter medium . Because the resulting spacing of the pocket from the first end face and from the second end face, a distance is always formed between the walls of the pocket and the filter media, in which the cleaned liquid can flow. In addition, the bag is particularly stable because it connects to the support frame wall on at least four sides.

The fact that the at least one pocket is spaced apart from the first filter medium by a first distance and the at least one pocket is spaced apart from the second filter medium by a second distance advantageously ensures that the filtration surface of the two filter media is not impaired by the at least one pocket becomes. The first distance and / or the second distance can be, for example, at least 1 mm, preferably at least 3 mm, particularly advantageously at least 5 mm and very particularly advantageously at least 1 cm. For example, the first and the second distance are 2mm or 3mm or 4mm.

In this way, particularly good fluid circulation is ensured at all points of the two filter media.

The fact that the at least one pocket takes up at least 50% of the interior space, preferably at least 60%, particularly preferably at least 70% and very particularly preferably at least 80% of the volume of the interior space, has the advantageous effect that the amount of air to be pumped out during the initial start-up is reduced considerably, and in this way can be completely removed particularly easily by a pumping process.

It can also be provided that the at least one pocket only takes up at least 35% of the volume of the interior.

The interior space is enclosed by the two filter media and the supporting frame wall. The volume of the interior space is limited by the elements mentioned.

The fact that the support frame has a plurality of pockets that are open to the outside of the liquid filter and that extend into the interior space, with adjacent pockets being separated from one another by a web arranged on the support frame, advantageously ensures that the support frame also has a large interior space. Volume or volume of the interior is particularly stable. As a result, it is particularly stable against collapsing, during transport or when it is arranged in the tank and the tank is being filled, as long as the liquid filter is still filled with air. Furthermore, advantageously, the volume of liquid that can be accommodated in the tank is not excessively impaired, since the liquid to be cleaned can get into the interior of the pockets through the openings in the pockets.

In principle, it is also possible that not every pocket is directly open to the external environment of the liquid filter or to its external space. For example, a pocket can be open to the outside of the liquid filter or to the outside space, and the webs which delimit adjacent pockets from one another can have openings so that an exchange of liquid can take place between the pockets.

In a development it is provided that at least one web is arranged with a first end on a first wall section of the support frame and with a second end opposite the first end is arranged on a second wall section of the support frame. The web runs between the first end and the second end through the interior. It can be provided, for example, that the first wall section and the second wall section are opposite one another.

This has the advantageous effect that the support frame is particularly stable. For example, the at least one web can be thus extend in a plane perpendicular to the z-direction (an xy plane).

The fact that at least one space is formed in the interior that connects the first filter medium to the second filter medium in a fluid-conducting manner, advantageously ensures that the interior is not divided into two fluid-tightly separated spaces by the at least one pocket. In this way it can advantageously be ensured that a single outlet or filter outlet is sufficient to transport the cleaned fluid present in the interior (the interior here, for example, forms the clean side) out of the liquid filter. The at least one space can be designed, for example, as a type of liquid channel or fluid channel. For example, it can extend essentially along the z-direction.

In a further development, it is provided that at least one pocket has a through opening in a pocket wall arranged in the interior, a first filter element being arranged in the interior, which is connected in a fluid-conducting manner to the external environment of the liquid filter by means of the through opening. The first filter element can have a third filter medium, for example.

The arrangement of the first filter element (also referred to simply as the filter element in the following) has the advantageous effect that the effective filtration area is enlarged. The liquid to be cleaned can get through the at least one pocket with the passage opening onto a raw side of the (first) filter element and after passing through the filter element into the interior of the liquid filter, it can be cleaned of particles (the liquid can e.g. through the third filter medium of the filter element pass through, the third filter medium holding back the particles). In this way, the service life of the liquid filter is advantageously increased.

This also advantageously further reduces the volume of the interior space from which the air has to be pumped out during initial start-up.

In a further development it is provided that the first filter element or the filter element has a further support frame with a further support frame wall, the further support frame wall having a third end face, the third filter medium being attached to the third end face in a fluid-tight manner.

This advantageously brings about a further stabilization of the liquid filter. As a result, the first filter element is particularly advantageously designed to be particularly stable and secured against collapse even in the event of pressure fluctuations. Finally, this advantageously has the effect that the individual elements of the liquid filter, in particular the filter media, are always spaced from one another, so that free circulation of the liquid in the liquid filter is ensured.

According to a second aspect of the invention, the use of a liquid filter in a tank filter system is proposed. The tank filter system is set up for installation in a tank. This can for example be a tank of a motor vehicle.

The tank filter system has a support structure, a heating element for heating a liquid in the tank and a liquid filter as described above. The tank filter system also has a pump which is set up to pump the liquid out of the tank through the liquid filter. The heating element, the pump and the liquid filter are mounted on the support structure and form an integral unit.

The use of the liquid filter in the proposed tank filter system enables the liquid in the tank to be efficiently cleaned of particles. Furthermore, the heating element has the advantageous effect that the liquid does not freeze or gel even at low temperatures or that a frozen or gelled liquid is liquefied again. The formation of an integral unit by mounting the heating element, pump and liquid filter on the support structure makes it possible to design the tank filter system as a simple and manageable element in one piece and thus to be particularly easy to transport and, for example, to be mounted in the tank.

The liquid filter is particularly advantageously mounted on the tank filter system in such a way that it is arranged with at least one filter medium close to the bottom of the tank when the tank filter system is installed in the tank and is arranged with the other filter medium close to the heating element of the tank filter system. A distance between the first filter medium and the bottom of the tank is particularly preferably less than 2 cm, very particularly preferably less than 5 mm, and a distance between the second filter medium and the heating element is less than 5 cm, preferably less than 3 cm and most preferably less than 1 cm.

drawings

Further features and advantages of the present invention will become more exemplary to those skilled in the art from the following description Embodiments, which however are not to be interpreted as limiting the invention, can be seen with reference to the accompanying drawings.

• 1: Eine schematische perspektivische Ansicht eines Tankfiltersystems;
• 2: eine perspektivische Ansicht eines Flüssigkeitsfilters;
• 3: einen schematischen Querschnitt durch den Flüssigkeitsfilter aus 2;
• 4: einen weiteren schematischen Querschnitt durch den Flüssigkeitsfilter aus 2;
• 5: einen weiteren schematischen Querschnitt durch den Flüssigkeitsfilter aus 2;
• 6: eine geöffnete perspektivische Aufsicht auf einen weiteren Flüssigkeitsfilter;
• 7: einen schematischen Querschnitt durch den Flüssigkeitsfilter aus 6.

Show it

• 1 : A schematic perspective view of a tank filter system;
• 2 : a perspective view of a liquid filter;
• 3 : a schematic cross section through the liquid filter 2 ;
• 4th : Another schematic cross section through the liquid filter 2 ;
• 5 : Another schematic cross section through the liquid filter 2 ;
• 6th : an opened perspective plan view of a further liquid filter;
• 7th : a schematic cross section through the liquid filter 6th .

1 Figure 10 is a schematic perspective view of a tank filter system 100 The tank filter system 100 has a tank 102 for a liquid up. The liquid can be, for example, a fuel, for example diesel or gasoline. It is also possible that the liquid is an aqueous (urea) solution, for example for an SCR system for exhaust gas aftertreatment of an internal combustion engine.

The liquid in the tank 102 is unfiltered, so it is in the tank 102 a raw side 103a of the tank filter system 100 in front. The Tank 102 is from an outside space 106 of the tank 102 surround. The Tank 102 points in its interior or in its tank interior 103 , ie on the raw side 103a , a liquid filter 1 on. The raw side 103a that are in the tank interior 103 of the tank 102 is located, represents an outdoor environment 9 of the liquid filter 1 The liquid filter 1 is designed to separate particles from the liquid. The liquid filter 1 is in the 2 to 7th shown in more detail. The tank filter system 100 is in the tank 102 assembled. It has a support structure 60 on, a heating element 70 to heat the in the tank 102 liquid, the liquid filter 1 as well as a pump 80 that is set up to remove the liquid from the tank 102 through the liquid filter 1 to pump. The heating element 70 , the pump 80 and the liquid filter 1 are on the support structure 60 assembled and form an integral unit. The heating element 70 , the pump 80 and the liquid filter 1 can for example by screw connections or clip connections, etc. on the support structure 60 be mounted. The support structure 60 can for example be designed as an injection-molded part made of plastic or it can be made of a metal. The support structure 60 can for example be made in one piece. The tank filter system 100 is thus in the assembled state as a manageable in a single part, for example from the tank 102 Detachable unit formed in one piece. However, for maintenance or repair purposes, one of the elements (pump 80 , Heating element 70 or liquid filter 1 ) from the support structure 60 be solved particularly advantageously non-destructively, for example by opening a screw connection, etc. and serviced or replaced.

In the 1 is from the pump 80 only an outer protective cover can be seen. The pump 80 is located under the cover.

The tank filter system 100 is preferred on a floor 105 of the tank 102 assembled. In this way, the one at a lower end of the carrier 60 arranged liquid filter 1 even with an almost empty tank 102 are advantageously in contact with the liquid. This allows the liquid to be filtered in the tank 102 through the liquid filter 1 to that of the tank filter system 100 connected consumers are promoted. The direction of gravity is denoted by the arrow and the reference symbol g pointing downwards in the figure. A coordinate system is also shown for better orientation, the z-direction in the direction of the direction of gravity g in the 1 facing down. The tank bottom 105 thus extends in the xy plane.

2 Figure 11 shows a perspective view of a liquid filter 1 such as in the tank filter system 100 out 1 can be mounted.

The liquid filter 1 is set up to separate particles from the liquid, for example a fuel or a urea solution. He has a first filter medium 10 , a second filter medium 20th as well as a support frame 2 with a supporting frame wall 3 on. The filter media 10 , 20th can for example be designed as thin membranes. They can be designed, for example, as a surface filter or as a depth filter. The supporting frame wall 3 has a first end face 4th which points along the z-direction (thus downwards in the figure, thus also along the direction of gravity g). The supporting frame wall 3 furthermore has one of the first end face 4th remote second end face 5 on, the first filter medium 10 is on the first face 4th attached fluid-tight. The second filter medium 20th is on the second face 5 attached fluid-tight. The support frame 2 , the first filter medium 10 and the second filter medium 20th enclose an interior 7th . The liquid filter 1 is from the outside environment 9 surround, on which, for example, the unfiltered liquid is. The Support frame 2 has at least one pocket 6th on that are in the interior 7th extends. In the illustrated embodiment there are five pockets 6th to recognize.

The five pockets 6th are to the outside environment 9 of the liquid filter 1 designed open so that the liquid in the pockets 6th can penetrate. However, the bags are 6th in this embodiment, all of the interior space 7th completely closed so no liquid from any of the pockets 6th in the interior 7th can penetrate.

The bags 6th are in the support frame 2 viewed along the z-direction between the first end face 4th and the second face 5 educated. They point from the first filter medium 10 a first distance d1 on and from the second filter medium 20th a second distance d2. The pocket height d3 extends along the z-direction. A total height d of the liquid filter 1 , which between the first filter medium 10 and the second filter medium 20th is determined, can for example be between 5mm and 200mm, preferably between 10mm and 50mm, for example the filter height or total height d is 20mm or 30mm or 40mm. The filter height or overall height d can be composed, for example, of the first distance d1, the second distance d2 and the pocket height d3. For example, the first distance is between 1 mm and 25 mm, preferably between 3 mm and 15 mm. The second distance d2 is likewise, for example, between 1 mm and 25 mm, preferably between 5 mm and 15 mm. The pocket height d3 is, for example, between 1 mm and 25 mm, preferably between 5 mm and 15 mm. In an exemplary embodiment, the total height d of the filter can be, for example, 20 mm, the pocket height d3 5 mm and the first distance d1 and the second distance d2 each 7.5 mm.

The bags 6th can have a rectangular shape in a cross section along the xz plane.

The bags 6th can be designed such that they are between 15% and 70% of the volume of the interior 7th take, for example 20% or 30% or 60%. This is the case when the liquid filter is started up for the first time 1 volume of air to be pumped off in the interior 7th significantly reduced.

In 2 it can also be seen that the majority of the pockets 6th extend side by side along the xy plane and are all arranged at the same height. There are adjacent pockets 6th in the supporting frame wall 3 separated from each other.

3 FIG. 4 shows a schematic cross section along an xy plane through the liquid filter from FIG 2 .

In the figure shown, it can be clearly seen that the five pockets 6th on a first wall section 11 the supporting frame wall 3 of the support frame 2 (pointing downwards in the figure) are designed to be open. The thick arrows indicate that from the side of this first wall section 11 Liquid in the open pockets 6th can penetrate. This is how it goes from the pockets 6th occupied volume is the volume of the tank 102 , in which the liquid filter 1 can be arranged, not lost.

It can also be seen that the five pockets 6th in this embodiment through the entire interior 7th extend along the xy plane, with the exception of one space 13th , which in the interior 7th is designed such that it is the first filter medium 10 and the second filter medium 20th fluidly connects to each other. Adjacent pockets 6th are each by one on the support frame 2 arranged web 40 separated from each other. Besides, the room is 13th , which is the first filter medium 10 with the second filter medium 20th connects to one another in a fluid-conducting manner in the manner of a fluid channel or a through-channel, through a web of the pocket adjacent to it 6th separated fluid-tight. The space 13th is therefore located on the clean side of the liquid filter 1 .

In this exemplary embodiment, all of the webs have 40 a first ending 41 on which on the first wall section 11 of the support frame 2 or the supporting frame wall 3 is arranged. All bridges 40 still have a second end 42 on which end the first 41 opposite. This second ending 42 is in each case on a second wall section 12 of the support frame 2 or the supporting frame wall 3 arranged. The webs run 40 straight in this embodiment. The bridges 40 run between the first end 41 and the second end 42 through the interior 7th . The first wall section 11 and the second wall section 12 lie opposite one another, viewed here along the y-direction, the first wall section 11 and the second wall section 12 are each slightly curved. The two curved wall sections 11 , 12 run almost parallel to each other. Through the bridges 40 are the bags 6th delimited from each other and one by the pockets 6th trained intermediate level 17th in the interior 7th is through the webs 40 stabilized. The entire liquid filter 1 gets through the webs 40 a more rigid and torsion-resistant structure, making it more robust against pressure fluctuations, vibrations, etc. In the figure there is a filter outlet at the top 8th of the liquid filter 1 to recognize through which the purified liquid the interior 7th of the liquid filter 1 can leave.

4th shows a further schematic cross section through the liquid filter 1 out 2 . In this figure it is easy to see how through the pockets 6th the intermediate level 17th is formed along perpendicular to the z-direction, which thus extends along the xy-plane. This intermediate level 17th reduces the volume of the interior 7th clear. The bags 6th extend from the first wall section 11 up to the second wall section 12 . The space 13th , which is the partial volume of the interior 7th which is the first filter medium 10 is facing, with that partial volume of the interior 7th connects which the second filter medium 10 is facing is indicated here by dashed lines. It is located outside of the section plane shown. It can be seen that the first filter medium 10 facing part of the interior 7th with the filter outlet 8th is fluidly connected.

5 shows a further schematic cross section along the xz plane through the liquid filter 1 out 2 . Here it is easy to see how the fluid flow from the external environment 9 through the first filter medium 10 (on the underside of the liquid filter 1 ) and through the second filter medium 20th (on the top of the liquid filter 1 ) he follows. The through the second filter medium 20th flowing liquid enters the interior 7th and initially flows above the intermediate level 17th going through the pockets 6th and the bags 60 separating webs 40 is formed on the right side. There it flows through the room 13th , which acts as a fluid-conducting channel, on the underside of the liquid filter 1 . It gets there into that part of the interior 7th which is between the intermediate level 17th and the first filter medium 10 is trained. From there, all of the cleaned liquid flows through a drain 16 from the interior 7th leading the purified liquid to the filter outlet 8th from which the cleaned liquid is directed to the consumer.

6th shows an opened perspective top view of a further exemplary embodiment of a liquid filter 1 . In this embodiment there are nine pockets 6th in the supporting frame wall 3 educated. At least one of the bags 6th has a through opening 15th in their pocket wall 14th which in the interior 7th is arranged on. In the interior 7th is a first filter element 50 arranged, which by means of the through opening 15th fluid-conducting with the outside environment 9 of the liquid filter 1 connected is. The first filter element 50 has a third filter medium 30th on, which is designed to separate particles from the liquid. This can be designed as a thin membrane, for example. It can be designed as a surface filter or as a depth filter, for example. The first filter element 50 also has another support frame here 55 on which another supporting frame wall 52 having. The further supporting frame wall 52 a third face 54 on, the third filter medium 30th on the third face 54 is attached fluid-tight. The first filter element 50 thus has one of the third filter medium 30th and the further supporting frame wall 52 enclosed interior 51 on which one with the raw side 103a is fluidly connected. In this way, by means of the third filter medium 50 the filtration capacity of the liquid filter 1 can be increased significantly without thereby reducing the volume of the liquid filter 1 in the tank 102 occupies, would have to be enlarged.

The further support frame 55 points on one of the third end face 54 facing away from a closed, fluid-impermeable bottom, which also a pocket wall of the other pockets 6th represents or part of the webs 40 represents which between the pockets 6th are arranged. In the illustrated embodiment, the third end face has a normal installation position of the liquid filter 1 up.

The first filter element 50 is from that of the interior 7th area of the first filter medium to be assigned 10 spaced.

It is possible that in at least one pocket 6th in another in the interior 7th arranged pocket wall a further through opening is provided. This can be done in the interior 7th a second filter element can be arranged, which by means of the further passage opening is fluid-conducting with the external environment 9 of the liquid filter 1 connected is. This second filter element can have a fourth filter medium. The second filter element can also have a support frame with a support frame wall and a fourth filter medium can be fastened in a fluid-tight manner on a fourth end face of this support frame wall. The second filter element can be in that part of the interior 7th be arranged, which between the pockets 6th and the first filter medium 10 is arranged. The fourth filter medium (for example a thin membrane, for example a depth filter or a surface filter) can advantageously be different from the first filter medium 10 be spaced apart. The arrangement of a second filter element can reduce the filtration capacity of the liquid filter 1 continue to increase advantageously.

The first filter medium 10 , the second filter medium 20th , the third filter medium 30th and / or the fourth filter medium can, for example, have a flat design, for example in the manner of a filter membrane.

Furthermore, it can be provided that in the interior of the first filter element 50 and / or a support structure is provided in the interior of the second filter element, which is not present here, which has at least one support element. This at least one support element can be essentially parallel to the first filter medium 10 or to the second filter medium 20th run away. A plurality of ribs can be arranged on the support element, which ribs extend from the support element in the direction of the first filter medium 10 and / or in the direction of the second filter medium 20th protrude out.

In the illustrated embodiment of 6th is the process 16 from the interior 7th which the cleaned liquid to the filter outlet 8th conducts, between the second filter medium 20th on the top of the liquid filter 1 and the first filter element 50 or the third filter medium 30th arranged.

7th shows a schematic cross section through the liquid filter 1 out 6th . In the figure it is clearly visible how the liquid from the tank 102 through the first filter medium 10 or the second filter medium 20th flows or as it flows through the with the passage opening 15th provided pocket 6th inside 51 of the first filter element 50 flows and then through the third filter medium 30th in the interior 7th got.

The tank filter system 100 or the liquid filter 1 are suitable, for example, for filtering fuels such as B. diesel or gasoline and especially for liquids which are used in SCR systems, e.g. B. aqueous urea solutions. Basically, the tank filter system 100 also be suitable for filtering water.

Claims (11)

Liquid filter for separating particles from a liquid, in particular from fuel or a urea solution, comprising: - a first filter medium (10), - a second filter medium (20), - A support frame (2) with a support frame wall (3), wherein the support frame wall (3) has a first end face (4) which points along a z-direction and wherein the support frame wall (3) is one of the first end face (4) has remote second end face (5), wherein the first filter medium (10) is fastened in a fluid-tight manner on the first end face (4), wherein the second filter medium (20) is attached to the second end face (5) in a fluid-tight manner, wherein the support frame (2), the first filter medium (10) and the second filter medium (20) enclose an interior space (7), wherein the liquid filter (1) is surrounded by an external environment (9), wherein the support frame (2) has at least one pocket (6) which extends into the interior (7), wherein the pocket does not allow any connection from the exterior of the liquid filter or the exterior of the liquid filter to the interior. Liquid filter according to the preceding claim, wherein the at least one pocket (6) is open to the external environment (9) of the liquid filter (1). Liquid filter according to one of the preceding claims, the at least one pocket (6) in the support frame (2), viewed in the z direction, being formed between the first end face (4) and the second end face (5). Liquid filter according to one of the preceding claims, wherein the at least one pocket (6) is spaced from the first filter medium (10) by a first distance (d1) and wherein the at least one pocket (6) is spaced from the second filter medium (20) by a second distance (d2). Liquid filter according to one of the preceding claims, wherein the at least one pocket (6) takes up at least 50%, preferably at least 70% of the interior space (7). Liquid filter according to one of the preceding claims, wherein the support frame has a plurality of pockets (6) which are open to the outside environment (9) of the liquid filter (1) and which extend into the interior (7), adjacent pockets (6) being separated from one another by a web (40) arranged on the support frame (2). Liquid filter according to the preceding claim, wherein at least one web (40) is arranged with a first end (41) on a first wall section (11) of the support frame (2) and with a second end (42) opposite the first end (41) on a second wall section (12) of the support frame (2) is arranged, wherein the web (40) between the first end (41) and the second end (42) runs through the interior space (7), wherein in particular the first wall section (11) and the second wall section (12) are opposite one another. Liquid filter according to one of the preceding claims, wherein in the interior space (7) at least one space (13) is formed which connects the first filter medium (10) with the second filter medium (20) in a fluid-conducting manner. Liquid filter according to one of the preceding claims, wherein at least one pocket (6) has a through opening (15) in a pocket wall (14) arranged in the interior (7), wherein a first filter element (50) is arranged in the interior (7), which is connected in a fluid-conducting manner to the external environment (9) of the liquid filter (1) by means of the through opening (15), wherein the first filter element (50) in particular has a third filter medium (30). Liquid filter according to the preceding claim, wherein the first filter element (50) has a further support frame (55) with a further support frame wall (52), wherein the further support frame wall (52) has a third end face (54), wherein the third filter medium (30) is attached to the third end face (54) in a fluid-tight manner. Use of a liquid filter (1) according to one of the preceding claims in a tank filter system, set up for installation in a tank, in particular in a tank of a motor vehicle, having the tank filter system (100) in addition to the liquid filter (1), - a support structure (60), - A heating element (70) for heating a liquid in the tank (102), - A pump (80) which is set up to pump the liquid from the tank (102) through the liquid filter (1), the heating element (70), the pump (80) and the liquid filter (1) on the support structure (60) are mounted and form an integral unit.

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