阅读说明：本技术 过滤器壳体以及中间底板 (Filter housing and intermediate base plate ) 是由 G·科伊森 J·塞梅 于 2018-05-23 设计创作，主要内容包括：本发明涉及一种过滤器壳体(1),其包括：接收部(11),用于接收车辆的过滤器模块；入口(7),用于将未经过滤的流体供应至所述过滤器模块的未净化侧(9)；出口(8),用于将经过滤的流体从所述过滤器模块的净化侧(10)导出；贯通开口(3),用于在所述出口(8)和所述过滤器模块的净化侧(10)之间建立流体连通；旁路开口(4),用于在所述出口(8)和所述过滤器模块的未净化侧(9)之间建立流体连通；第一止回元件(5),用于选择性地闭合所述贯通开口(3)；和第二止回元件(6),用于选择性地闭合所述闭旁路开口(4),其中,所述第一止回元件(5)阻断流体从所述过滤器壳体(1)的出口(8)流到所述过滤器模块的净化侧(10),并且其中,所述第二止回元件(6)阻断流体从所述过滤器模块的未净化侧(9)流到所述过滤器壳体(1)的出口(8),并且本发明涉及一种用于在车辆的过滤器模块和过滤器壳体(1)之间引入的中间底板,其中,所述过滤器模块能够置入所述过滤器壳体(1)的接收部(11)中,所述中间底板包括贯通开口(3),用于在出口(8)和所述过滤器模块的净化侧(10)之间建立流体连通；旁路开口(4),用于在所述出口(8)和所述过滤器模块的未净化侧(9)之间建立流体连通；第一止回元件(5),用于选择性地闭合所述贯通开口(3)；和第二止回元件(6),用于选择性地闭合所述闭旁路开口(4),其中,所述第一止回元件(5)阻断流体从所述过滤器壳体(1)的出口(8)流到所述过滤器模块的净化侧(10),其中,所述第二止回元件(6)阻断流体从所述过滤器模块的未净化侧(9)流到所述过滤器壳体(1)的出口(8)。(The invention relates to a filter housing (1) comprising: a receiving section (11) for receiving a filter module of a vehicle; an inlet (7) for supplying unfiltered fluid to an uncleaned side (9) of the filter module; an outlet (8) for leading filtered fluid out of the clean side (10) of the filter module; a through opening (3) for establishing fluid communication between the outlet (8) and a clean side (10) of the filter module; a bypass opening (4) for establishing fluid communication between the outlet (8) and a raw side (9) of the filter module; a first non-return element (5) for selectively closing said through opening (3); and a second check element (6) for selectively closing the closed bypass opening (4), wherein the first non-return element (5) blocks fluid flow from the outlet (8) of the filter housing (1) to the clean side (10) of the filter module, and wherein the second non-return element (6) blocks the fluid flow from the raw side (9) of the filter module to the outlet (8) of the filter housing (1), and the invention relates to an intermediate floor for introduction between a filter module and a filter housing (1) of a vehicle, wherein the filter module can be inserted into a receptacle (11) of the filter housing (1), the intermediate base plate comprising a through-opening (3), for establishing fluid communication between an outlet (8) and a clean side (10) of the filter module; a bypass opening (4) for establishing fluid communication between the outlet (8) and a raw side (9) of the filter module; a first non-return element (5) for selectively closing said through opening (3); and a second non-return element (6) for selectively closing the closed bypass opening (4), wherein the first non-return element (5) blocks fluid flow from the outlet (8) of the filter housing (1) to the clean side (10) of the filter module, wherein the second non-return element (6) blocks fluid flow from the uncleaned side (9) of the filter module to the outlet (8) of the filter housing (1).)

1. A filter housing (1) comprising:

a receiving unit (11) for receiving a filter module (2) of a vehicle,

an inlet (7) for supplying unfiltered fluid to a raw side (9) of the filter module (2),

an outlet (8) for leading filtered fluid out of a clean side (10) of the filter module (2),

a through opening (3) for establishing a fluid communication between the outlet (8) and a clean side (10) of the filter module (2),

a bypass opening (4) for establishing fluid communication between the outlet (8) and a raw side (9) of the filter module (2),

a first non-return element (5) for selectively closing said through opening (3), and

a second check element (6) for selectively closing the closed bypass opening (4),

wherein the first non-return element (5) blocks a fluid flow from the outlet (8) of the filter housing (1) to the clean side (10) of the filter module (2), and

wherein the second non-return element (6) blocks fluid flow from the raw side (9) of the filter module (2) to the outlet (8) of the filter housing (1).

2. An intermediate floor (22) introduced between a filter module (2) and a filter housing (1) of a vehicle, wherein the filter module (2) can be inserted into a receptacle (11) of the filter housing (1), the intermediate floor (22) comprising:

a through opening (3) for establishing a fluid communication between an outlet (8) of the filter housing (1) and a clean side (10) of the filter module (2),

a bypass opening (4) for establishing fluid communication between an outlet (8) of the filter housing (1) and a raw side (9) of the filter module (2),

a first non-return element (5) for selectively closing said through opening (3), and

a second check element (6) for selectively closing the closed bypass opening (4),

wherein the first non-return element (5) blocks a fluid flow from the outlet (8) of the filter housing (1) to the clean side (10) of the filter module (2), and

wherein the second non-return element (6) blocks fluid flow from the raw side (9) of the filter module (2) to the outlet (8) of the filter housing (1).

3. Filter housing (1) or intermediate floor (22) according to one of the preceding claims, characterised in that it has a stop (12) for resting against the filter module (2), wherein the stop (12) has at least one bypass connection (13) by means of which the raw side (9) of the filter module (2) is in fluid communication with the bypass opening (4).

4. Filter housing (1) or intermediate floor (22) according to claim 3, characterised in that the receiving portion (11) is configured as a hollow cylinder or cone, wherein the through-opening (3) and the bypass opening (4) are arranged on an end side (24) and the stop (12) extends in the circumferential direction and the bypass connection (13) in the stop (12) extends in the radial direction.

5. Filter housing (1) or intermediate floor (22) according to one of the preceding claims, characterized in that it has a clean-side connection (14) for connecting the outlet (8) and the clean side (10) of the filter module (2), in particular fluid-tightly, wherein the clean-side connection (14) comprises the through-opening (3).

6. Filter housing (1) or intermediate floor (22) according to claims 4 and 5, characterised in that at least two bypass openings (4) are arranged concentrically around the through opening (3) arranged centrally on the end side (24).

7. Filter housing (1) or intermediate bottom plate (22) according to one of the preceding claims, characterized in that the first non-return element (5) and/or the second non-return element (6) is configured as a check valve and/or is made of an elastic material.

8. Filter housing (1) or intermediate floor (22) according to one of the preceding claims, characterised in that the first non-return element (5) is configured as a diaphragm valve or a screen valve or a beak valve or a ball valve and/or the second non-return element (6) is configured as a diaphragm valve or a screen valve or a beak valve or a ball valve.

9. Filter housing (1) or intermediate floor (22) according to one of the preceding claims, characterised in that the deviation of the cross-sectional area of the through-opening (3) from the cross-sectional area of the bypass opening (4) is at most 15%, in particular at most 10%, preferably at most 5%.

10. The intermediate floor (22) according to any of claims 2 to 9, characterized in that it has an additional stop (16) for resting against the filter housing (1), wherein the additional stop (16) has at least one through-connection (15) for fluid communication with the outlet (8).

11. A liquid filter (23) for a motor vehicle, comprising a filter housing (1) according to any one of claims 1 to 9 and a filter module (2).

12. A liquid filter (23) for a motor vehicle, comprising an intermediate floor (22) according to one of claims 2 to 10 and a filter module (2).

Technical Field

The present invention relates to a filter housing. The invention further relates to an intermediate floor plate which is introduced between the filter module and the filter housing. The filter module is in particular used for filtering liquids of a motor vehicle, and is particularly advantageously used for filtering fuel and/or urea solutions. Within the scope of the present invention, the terms "having" and "including" are used synonymously.

Background

Filter modules are known from the prior art. Such filter modules are commonly used in vehicles in order to filter the urea solution required in the vehicle in order to reduce nitrogen oxide emissions. However, the urea solution can freeze at low temperatures and thereby cause damage to the ice pressure in the filter module. In a vehicle, it is therefore provided that the entire system for injecting the urea solution is emptied when the vehicle is stationary. For this purpose, the pumping direction must be reversed in order to pump the entire urea solution reserve present in the system back into the tank in which the urea solution is stored and, in normal operation, to take the urea solution from the tank for injection into the exhaust system of the vehicle.

However, a reversal of the pumping direction may result in dirt particles adhering to the filter module being released and thus being directed towards the pump. This can lead to blockage and/or contamination of the lines on the one hand and to failure of the pump on the other hand. Therefore, filter modules with a backflow function are known from the prior art to avoid this problem. Such a filter module is described, for example, in DE 102014013852 a 1.

Disclosure of Invention

The filter housing according to the invention or the intermediate floor according to the invention allows the return flow function to be transferred from the filter module and to be implemented in the filter housing or in the intermediate floor. The filter module can therefore be produced simply and inexpensively. The filter module can in particular be produced similarly to a conventional filter module without a non-return function. Furthermore, the filter module can be replaced simply and inexpensively. At the same time, a check function is ensured in any case, which means that a reversal of the pumping direction prevents a fluid flow through the filter module, whereby no particles are released from the filter module.

The filter housing of the invention comprises a receiving portion for receiving a filter module of a vehicle. The filter module is in particular part of a liquid filter of a vehicle and is therefore used for filtering liquids. The filter module is in particular designed for filtering fuel and/or aqueous urea solution. The receptacle extends along a longitudinal axis of the filter housing, wherein the longitudinal axis is the axis of the filter housing along which the filter housing has the greatest extent. The filter module can thus advantageously be inserted into the receptacle along this longitudinal axis. The filter housing also has an inlet and an outlet. The inlet is used for supplying unfiltered fluid to the unfiltered side (rohsei) of the filter module, while the outlet is used for leading filtered fluid out of the purified side (reisei) of the filter module. Likewise, the filter housing also has a through opening and a bypass opening. The through opening is used to establish fluid communication between the outlet of the filter housing and the clean side of the filter module. The bypass opening is used to establish fluid communication between the outlet of the filter housing and the raw side of the filter module. Thus, if the fluid is to be transported from the filter module to the filter housing after being filtered by the filter module, the through openings have to be flowed through by the fluid. The bypass opening establishes communication of the raw side of the filter module with the outlet of the filter housing, so that fluid can reach the outlet bypassing the filter module. In this case, a first non-return element and a second non-return element are provided, wherein the through-opening can be selectively closed by means of the first non-return element and the bypass opening can be selectively closed by means of the second non-return element. Thus, undesired fluid flow through the through opening and the bypass opening may be prevented. The first check element blocks fluid flow from the outlet of the filter housing to the clean side of the filter module. At the same time, the second check element blocks fluid flow from the raw side of the filter module to the outlet of the filter housing. Thus, fluid is prevented by the second non-return element from reaching the outlet from the raw side through the bypass opening, which may cause the filter module to be bypassed. Thus, the second non-return element prevents fluid from reaching the outlet of the filter housing without being filtered.

Furthermore, the first non-return element also prevents that already filtered fluid can return to the filter module. In this way two different paths through the filter housing can be realized. On the one hand, a normal operation can be achieved in which fluid passes from the inlet to the raw side of the filter module, is filtered by the filter module and is then transported from the clean side of the filter module to the outlet of the filter housing. This occurs as fluid flows from the inlet to the outlet. However, if the fluid flow is reversed, especially in order to release the fluid in the fluid-conducting system, the fluid is transported from the outlet to the inlet. In this case, the fluid flow does not flow from the outlet to the clean side of the filter module, but flows via the bypass opening to the uncleaned side of the filter module. In particular, therefore, a backflow through the filter module itself, which could lead to the release of particles adhering to the filter module, is prevented. Thus, particles initially filtered by the filter module are not released from the filter module and therefore do not damage other components connected to the inlet or block the corresponding pipe.

The invention further relates to an intermediate floor plate which is introduced between the filter module and the filter housing. The filter module can be inserted into a receptacle of the filter housing. It is also preferably provided that the filter housing extends along a longitudinal axis, wherein the longitudinal axis is the axis along which the filter housing has the greatest extent. The filter module is inserted into the filter housing, in particular along the longitudinal axis. The intermediate bottom plate has a through opening for establishing fluid communication between the outlet of the filter housing and the clean side of the filter module. Likewise, the intermediate bottom plate also has a bypass opening for establishing fluid communication between the outlet of the filter housing and the raw side of the filter module. Additionally, the intermediate bottom plate has a first check element for selectively closing the through opening and a second check element for selectively closing the bypass opening. The first non-return element allows to block the fluid flow from the outlet of the filter housing to the clean side of the filter module, while the second non-return element enables to block the fluid flow from the uncleaned side of the filter module to the outlet of the filter housing. Thus, the same results as previously described with respect to the filter housing can be achieved. The components required for this purpose, however, are not integrated into the filter housing itself, but are arranged in an intermediate base plate in a removable manner. This makes it possible to add the aforementioned return function in the case of existing filter housings. It is thus ensured even in the case of existing filter housings that the return flow does not take place through the filter module but through a correspondingly arranged bypass opening.

The dependent claims have preferred embodiments of the inventive content.

Preferably, the filter housing or the intermediate base plate has a stop. The stop is intended to come into contact with the filter module when the filter module is inserted into the filter housing. The stop has at least one bypass connection. The bypass connection serves to connect the raw side of the filter module with the bypass opening for fluid communication, since otherwise the raw side and the bypass opening would be separated by a stop. Due to the stop, a conventional end cap of the filter module can be used, so that no special design of the end cap for the filter housing is required.

It is particularly advantageously provided that the receptacle for receiving the filter module is designed in the form of a hollow cylinder. The filter module is therefore preferably of cylindrical design. In particular, the hollow cylinder shape is configured along a longitudinal axis such that the longitudinal axis is the central axis of the hollow cylinder. The hollow cylinder shape thus defines an axial direction, i.e. a direction parallel to the longitudinal axis, and a radial direction, i.e. a direction perpendicular to the longitudinal axis. Also, a circumferential direction extending along the outer wall of the hollow cylinder shape is defined, which means that the circumferential direction extends circumferentially around the longitudinal axis. The intermediate floor is therefore also advantageously of cylindrical design, since it is also arranged in the receptacle, as is the filter module. The end face oriented perpendicular to the longitudinal axis can be defined by the hollow cylinder shape of the filter housing or by the cylinder shape of the intermediate floor. On the end side, a through opening and a bypass opening are arranged. The stop advantageously extends in the circumferential direction, while the bypass connection in the stop extends in the radial direction. The through-opening advantageously extends in the axial direction. In this way, the filtered fluid to be conducted from the outlet flow to the raw side can be conveyed radially outwards: fluid flows radially outward from the bypass opening through the bypass connection. The bypass connection advantageously opens into an intermediate space which is not occupied by the filter module after the filter module has been inserted into the receptacle. In particular, the intermediate region is placed radially outside the filter module. Thus, fluid can be conveyed to the raw side of the filter module through the bypass opening and in particular through the bypass connection. At the same time, it is ensured by the first non-return element that no fluid can reach the clean side of the filter module, so that particles in the filter module cannot be released from the outer surface of the filter module, for example, when a radial through-flow occurs from the outside to the inside in normal operation.

In a preferred embodiment, the filter housing or the intermediate floor has a clean-side connection. The clean side connection serves to connect the outlet and the clean side, wherein the connection is sealed off in a fluid-tight manner in particular. It is thus ensured that the fluid can reach the outlet directly after being filtered by the filter module. Also, no fluid that is not filtered by the filter module can reach the outlet. The clean-side connection therefore comprises, in particular, a through-opening. Furthermore, the clean-side connection advantageously serves to separate the clean side from the raw side when the filter module is inserted into the filter housing or is placed against the intermediate base plate. In particular, the clean-side connection has a sealing element for bearing against the filter module in a fluid-tight manner. Thus, said fluid-tight connection of the outlet and the clean side is achieved.

It is particularly advantageously provided that the at least two bypass openings are arranged concentrically around a through opening arranged centrally on the end side. Thus, by providing a plurality of bypass openings each individual bypass opening may be configured smaller than the through opening, while at the same time enabling the same fluid flow as through opening to also pass through the bypass opening. By this arrangement, the geometry of the filter housing and/or the intermediate floor can be optimally utilized. As already mentioned, the end face is advantageously designed to be circular, since it is part of the cylindrical shape of the intermediate floor or the hollow cylindrical shape of the filter housing. By providing one central through opening and a plurality of smaller bypass openings, each opening can be sealed individually, safely and reliably, so that fluid flow occurs only in the desired direction.

The first non-return element and/or the second non-return element are advantageously configured as a non-return valve and/or are made of an elastic material. Thus, the autonomous opening and closing of the bypass opening and the through opening is performed according to the prevailing partial pressure. In particular during normal operation of the filter housing and/or the intermediate floor, fluid is transported from the inlet to the outlet. This results in a higher partial pressure on the clean side than at the outlet, and also on the raw side than at the outlet. This causes the first check to open and the second check to close. Thus, the bypass opening is blocked, while the through opening allows fluid flow. Conversely, if the conveying direction is reversed, the partial pressure at the outlet is higher on the clean side (and possibly on the raw side) of the filter module. This results in the first check blocking fluid flow and the second check allowing fluid flow. It is thus ensured that an optimized path is always used, depending on the selected throughflow direction through the filter housing. In the case of a common operating direction, it is therefore ensured that only filtered fluid can reach the outlet, whereas in the return operation it is ensured that no particles are released from the filter module.

The first non-return element is preferably designed as a diaphragm valve or as a screen valve (Schirmventil) or as a beak valve (schnabelvalve) or as a ball valve. Advantageously, the second non-return element is also configured as a diaphragm valve or as a screen valve or as a beak valve or as a ball valve. The first non-return element and/or the second non-return element preferably have a sealing lip with a fixing foot. The fastening foot has a mushroom-shaped configuration and can be guided through the opening in order to hold the first non-return element and/or the second non-return element at the desired location. It is also particularly advantageously provided that the first non-return element is designed in the form of a disk, wherein the diameter of the first non-return element is in particular greater than the diameter of the through-opening. The second non-return element is preferably also of disk-shaped design, wherein the diameter of the second non-return element is in particular greater than the diameter of the bypass opening. The element configured in the form of a disc is advantageously fastened to the filter housing or to the intermediate floor via the aforementioned fastening feet. Due to the disk shape, the first and/or second non-return element rests against the filter housing or the intermediate floor. If the fluid flow is in a direction in which the first and/or second non-return element should block, the corresponding dished region is pressed by the fluid flow onto the filter housing or onto the intermediate bottom plate. Since the diameter of the first check is greater than the diameter of the through opening and the diameter of the second check is greater than the diameter of the bypass opening, no fluid can flow through either the through opening or the bypass opening. Conversely, if the first or second check allows fluid flow, the fluid flow must lift the disc-shaped first or second check from the through opening or the bypass opening. In this way, the throughflow through the filter housing or the intermediate floor can be regulated simply and with little effort, without any complicated intervention from the outside being necessary.

In particular, the deviation of the cross-sectional area of the through-opening from the cross-sectional area of the bypass opening is at most 15%, preferably at most 10%, in particular at most 5%. In particular, it is provided in the case of a plurality of through-openings and/or bypass openings that all through-openings and/or all bypass openings have the same cross-sectional area. The cross-sectional area of each bypass opening and/or through-opening is in particular in the region of 0.38cm²To 0.44cm²In the meantime. The throughflow through the filter housing can thus be achieved independently of the flow direction. It can be provided that the deviation of the total cross-sectional area of the one or more through openings from the total cross-sectional area of the one or more bypass openings is at most 15%, preferably at most 10%, in particular at most 5%. The total cross-sectional area is to be understood here as the sum of the cross-sectional areas of the individual opening types.

Furthermore, the intermediate floor advantageously also has an additional stop. The additional stop serves to bring the intermediate base plate into contact with the filter housing. Furthermore, the additional stop has a through-connection in order to be able to achieve a fluid connection with the outlet. As with the above-described stop, the additional stop can also be designed, for example, in such a way that it extends in the circumferential direction of the hollow cylinder shape of the filter housing. The through-connection 15 can be mounted radially in an additional stop.

Finally, the invention relates to a liquid filter for a motor vehicle. The liquid filter has either a filter housing as described above or an intermediate bottom plate as described above. Additionally, the liquid filter has a filter module. The liquid filter thus allows a safe and reliable filtration of a fluid of a vehicle, in particular of a fuel or an aqueous urea solution, while at the same time a return flow operation through the liquid filter can be achieved. In the return operation, it is ensured that the risk of particles being released from the filter module is reduced in comparison with conventional filters. The filter module itself can be produced simply and inexpensively by means of the aforementioned filter housing and/or the aforementioned intermediate base plate, as a result of which the liquid filter, in particular the filter module, can be serviced simply and with little effort.

Drawings

Embodiments of the present invention are described in detail below with reference to the accompanying drawings. Shown in the drawings are:

figure 1 is a schematic view of a filter housing according to one embodiment of the invention,

figure 2 is another schematic view of a filter housing according to this embodiment of the invention,

figure 3 is a first schematic view of a liquid filter having a filter housing according to one embodiment of the invention,

figure 4 is a second schematic view of a liquid filter having a filter housing according to this embodiment of the invention,

figure 5 is a schematic view of a liquid filter having a filter housing according to this embodiment of the invention during a first mode of operation,

figure 6 is a schematic view of a liquid filter having a filter housing according to this embodiment of the invention during a second mode of operation,

figure 7 shows another schematic view of a liquid filter with a filter housing according to this embodiment of the invention during a second mode of operation,

figure 8 is a schematic view of an intermediate floor according to this embodiment of the invention,

figure 9 is a schematic cross-sectional view of an intermediate floor according to this embodiment of the invention,

FIG. 10 is another schematic view of an intermediate floor according to this embodiment of the invention, an

Fig. 11 is a schematic view of an intermediate bottom plate according to this embodiment of the invention, which is placed into the filter housing.

Detailed Description

Fig. 1 schematically shows a filter housing 1 according to one embodiment of the invention. The filter housing 1 comprises in particular an upper shell 25 and a lower shell 26, which can be assembled to constitute the filter housing 1. In this case, the lower shell 26 has a receptacle 11 into which the filter module 2 can be inserted (see fig. 3 to 7). The receptacle 11 is designed in the form of a hollow cylinder, the longitudinal axis 50 of which is the central axis of the filter housing 1, or alternatively in the form of a cone. The longitudinal axis 50 is the axis of the filter housing 1 along which the filter housing 1 has its greatest extent. If the filter module 2 is to be inserted into the receptacle 11, this is advantageously carried out by insertion along the longitudinal axis 50.

The various directions are defined by the hollow cylindrical shape of the receiving portion 11 of the filter housing 1. Therefore, the following directional description of axial always means parallel to the longitudinal axis 50. The directional description radial includes all directions perpendicular to the longitudinal axis 50. The direction in the circumferential direction extends circularly around the longitudinal axis 50. Furthermore, the filter housing 1 has a circumferential surface which extends around the longitudinal axis 50 and is the radial boundary of the receiving portion 11. Furthermore, the filter housing 1 has an end face 24 which is oriented perpendicularly to the longitudinal axis 50 and via which fluid can be conducted from the receptacle 11 to the outlet 8. Finally, there is an inlet 7 via which fluid can be conducted to the receiving portion 11.

The filter housing 1 enables a return flow of the fluid, wherein the usual flow direction of the fluid is from the inlet 7 through the filter module 2 to the outlet 8. Conversely, in return operation, fluid flows from the outlet 8 to the inlet 7. It must be ensured here that fluid does not flow through the filter module 2, since in this case particles which have already been filtered out by the filter module 2 would otherwise be released from the filter module 2. These particles can on the one hand block the piping along the inlet 7 or damage the components connected to the inlet 7. Therefore, one through opening 3 and a plurality of bypass openings 4 are mounted on the end face 24. In this embodiment, the through opening 3 comprises a plurality of individual openings. The through-openings 3 and each bypass opening 4 have, for example, 0.38cm²To 0.44cm²Cross-sectional area therebetween. For this purpose, fig. 2 shows a view from the angle of view a marked in fig. 1. It can also be provided that each individual opening of the through openings 3 has the same cross-sectional area as each bypass opening 4. Alternatively or additionally, it can be provided that the sum of the cross-sectional openings of the individual openings of the through-openings 3 substantially corresponds to the sum of the cross-sectional openings of the bypass openings.

In fig. 1 and 2, the through-opening 3 is shown arranged centrally on the end face 24, while a total of four bypass openings are arranged concentrically around the through-opening 3. Both the bypass opening 4 and the through opening 3 connect the outlet 8 with the receiving portion 11, so that fluid between the outlet 8 and the receiving portion 11 can be conducted through both the bypass opening 4 and the through opening 3. In particular, the outlet 8 extends from the hollow space 27, wherein the receptacle 11 is connected for fluid communication with the hollow space 27 via the through-opening 3 and the bypass opening 4.

The first non-return element 5 is arranged in the through-opening 3, wherein the central part opening in the through-opening 3 does not have to be suitable for a through-flow of fluid, but can be used, for example, as a receptacle or side recess for a retaining pin of a diaphragm valve or a screen valve. In this case, the cross-sectional area of such an opening is not counted in the cross-sectional area of the sum of all partial openings of the through-opening 3. The first non-return element 5 prevents a fluid flow from the outlet 8 through the through opening 3 to the receptacle 11. For this purpose, in this exemplary embodiment, the non-return element is designed as a non-return valve, wherein the first non-return element 5 can be designed, for example, as a diaphragm valve or a beak valve or a ball valve. In the bypass openings 4, in each case a second non-return element 6 is arranged. The second non-return element 6 prevents a fluid flow from the receiving portion 11 via the bypass opening 4 to the outlet 8. The second non-return element 6 is in particular also designed as a non-return valve, wherein the second non-return element 6 is designed, for example, as a diaphragm valve or a barrier valve or a beak valve or a ball valve.

Particularly advantageously, the first non-return element 5 and the second non-return element 6 each have a disk-shaped region with a diameter greater than the through-opening 3 (in the case of the first non-return element 5) or greater than the bypass opening 4 (in the case of the second non-return element 6). Thus, fluid can flow through the through opening 3 or the bypass opening 4 only if the fluid flow is oriented such that the dished region is lifted from the through opening 3 or the bypass opening 4. It is thus ensured by the non-return elements 5, 6 that only one possibility is provided when fluid is to be conveyed between the outlet 8 and the receptacle 11. This can only be achieved through the through-openings 3 if the fluid is to be transported from the receiving portion 11 to the outlet 8. Conversely, if the fluid is to be transported from the outlet 8 to the receiving portion 11, this can only be achieved through the bypass opening 4. In this way, it is ensured that a different flow path is used for the return flow operation than for the normal operation of the filter housing 1.

The end face 24 also has a stop 12. The stop 12 is mounted on the radially outer edge of the end face 24 and is intended to rest against the filter module 2. The end side 24 also has a purge side connection 14. The clean-side connection 14 is of hollow cylindrical design and extends in the circumferential direction around the through-opening 3. It is provided here that only the clean-side connection 14 is connected to the clean side of the filter module 2, so that filtered fluid can reach the through-opening 3 via the clean-side connection 14. In order to seal such a fluid path against external influences, the clean-side connection 14 advantageously has a seal 17. It is thus ensured that only filtered fluid can reach the outlet 8.

Furthermore, a plurality of radially extending bypass connections 13 are also present on the stop 12. The bypass connections 13 are in particular respective grooves in the stop 12. Particularly advantageously, a bypass connection 13 is present radially outside each bypass opening 4. This means that the positions of the bypass connection 13 and the bypass opening 4 in the circumferential direction are respectively the same. When the filter module 2 is in contact with the stop 12, the fluid flowing through the bypass opening 4 can also be conveyed past the stop 12 by the bypass connection 13.

Fig. 3 and 4 show a liquid filter 23. The liquid filter 23 comprises the filter housing 1 described above and shown in fig. 1 and 2. Additionally, the filter module 2 is inserted into the receptacle 11. The filter module 2 has a lower retaining element 19 and an upper retaining element 21, wherein a hollow cylindrical or conical filter medium 20 is present between the lower retaining element 19 and the upper retaining element 21. The lower retaining element 19 is sealed radially outwards with respect to the receiving portion 11 by means of a seal 28.

For clarity, the lower retaining element 19 and the filter media 20 are not shown in fig. 4, which is a view from the perspective B shown in fig. 3.

The filter module 2 has a clean side 10 which is located inside the volume enclosed by the filter medium 20. The raw side 9 is located radially outside the filter medium 20. The upper holding element 21 of the filter module 2 has an opening via which the clean side 10 can be connected for fluid communication with the outlet 8. The clean-side connection 14 engages in this opening and is sealed off from the upper retaining element 21 by means of a seal 17. Thus, a fluid flow from the clean side 10 to the outlet 8 can only be achieved via the through-openings 3. This situation is shown in fig. 5.

Fig. 5 shows the liquid filter 23 described above and shown in fig. 3 and 4 in the normal operating mode. In the normal operating mode, the liquid filter 23 is operated such that the first fluid flow 100 prevails. The first fluid flow 100 is directed from the inlet 7 to the outlet 8. Thus, fluid reaches the raw side 9 of the filter media 20 from the inlet 7. Next, the fluid is filtered through the filter medium 20, whereby the fluid passes from the raw side 9 to the clean side 10 of the filter medium 20.

The fluid passes from the clean side 10 through the clean side connection 14 and the through-opening 3 to the outlet 8. Since the partial pressure on the clean side 10 is higher than at the outlet 8, the first non-return element 5 opens. Thus, throughflow of the first fluid flow 100 can be achieved,

if the fluid reaches the bypass connection 13 along the raw side 9, the fluid flow through the bypass opening 4 is blocked by the second non-return element 6. The second non-return element 6 acts in particular counter to the direction of action of the first non-return element 5, so that sealing of the bypass opening 4 is achieved as the partial pressure on the raw side 9 is higher than at the outlet 8. Thus, fluid cannot reach the outlet 8 from the raw side 9 without being filtered.

Fig. 6 and 7 show the return operation of the liquid filter 23. Here, fig. 7 is a view from a viewing angle C in fig. 6. As already shown in fig. 4, the lower retaining element 19 and the filter medium 20 have been omitted in the illustration of fig. 7 in order to obtain a better overview.

In return operation, the second fluid flow 200 flows through the filter housing 1 and the filter module 2. This means that fluid flows from the outlet 8 through the fluid filter 23 to the inlet 7. In such a case, flow through the filter media 20 should be prevented to avoid this backflow releasing particulates from the filter media 20. Thus, the second fluid flow 200 is led through the bypass opening 4 and the bypass connection 13. This means that the fluid flow 200, proceeding from the outlet 8, reaches the raw side 9 of the filter module 2 via the bypass opening 4 and the bypass connection 13 while bypassing the filter medium 20. Since the partial pressure at the outlet 8 is greater than the partial pressure on the raw side 9 or on the clean side 10 of the filter module 2 in this fluid flow situation, the first non-return element 5 is closed and the second non-return element 6 is open. It is thus prevented that fluid can flow to the clean side 10 and from there through the filter medium 20 in the usual filtering direction of the normal operating mode. Instead, the fluid has to flow through the bypass opening 4 and the bypass connection 13, so that the release of particles from the filter module 2, in particular from the filter medium 20, is prevented. The filter medium may be configured, for example, as a radially (e.g., from the outside inward, or vice versa) or axially flowing through a wound filter (Wickelfilter) or as a radially flowing star filter. The filter medium may comprise or have, for example, cellulose and/or plastic nonwovens and/or meltblown materials as material.

An alternative embodiment of the invention is shown in figures 8 to 11. Fig. 8 to 10 show different views of the intermediate floor 22. Fig. 8 is a plan view of intermediate floor 22, fig. 9 is a sectional view taken along a section line a-a of fig. 8, and fig. 10 is a bottom view of intermediate floor 22. The intermediate base plate 22 is in particular of the same design as the front end 24 of the filter housing 1 described above.

Similar to the previously described filter housing 1, the intermediate base 22 has a stop 12 against which the filter module 2 can rest. The stopper 12 has a plurality of bypass connections 13. The intermediate floor 22 also has the aforementioned clean-side connection 14, wherein the clean-side connection 14 has a through-opening 3. In this embodiment, the through opening 3 again comprises a plurality of individual openings. Furthermore, there are a plurality of bypass openings 4. Similar to the previously described filter housing 1, there is a first non-return element 5 for selectively blocking the fluid flow through the through-opening 3, whereas the through-flow of fluid through the bypass opening 4 can be selectively blocked by a second non-return element 6.

The intermediate base plate 22 can be inserted into the filter housing 1, as shown in fig. 11. The filter housing 1 is in particular an element separate from the filter housing and/or a filter housing according to the prior art, wherein the intermediate base plate 22 can safely and reliably allow a return operation of the filter housing 1. Thus, an intermediate bottom plate 22 is introduced between the outlet 8 and the filter module 2, wherein the additional seal 18 seals the filter housing 1 with respect to the intermediate bottom plate 22. In this case, the intermediate base 22 rests with the additional stop 16 on the filter housing 1. The additional stop 16 extends in particular in the circumferential direction around the through-opening 3. In order to ensure a fluid flow from the through-opening 3 to the outlet 8, the additional stop 16 therefore has at least one through-connection 15.

If the intermediate base plate 22 is inserted into the filter housing 1, the filter housing 1 with the filter base 22 no longer differs from the previously described filter housing 1 in terms of function. The same operating modes described above and shown in fig. 5 to 7 can thus be realized.

The filter housing 1 according to the invention as described above and/or the intermediate base 22 according to the invention as described above make it possible to provide a liquid filter 23 with an advantageous possibility of back-flowing of fluid, wherein the filter module 2 to be used can also be produced simply and inexpensively as a wear part. The liquid filter 23 thus allows a simple and cost-effective replacement of the filter module 2, since all connections which are present in order to provide the possibility of backflow are mounted in the filter housing 1 or in the intermediate floor 22. Furthermore, the intermediate base plate 22 according to the invention can advantageously also realize a filter housing 1 which has no backflow possibility before and which is then provided with such a backflow possibility. Therefore, a conventional filter housing 1 can also be equipped with such a backflow possibility in that: the intermediate bottom plate 22 is inserted.