EP1879677A2

EP1879677A2 - Filter device, especially for filtering liquids in internal combustion engines

Info

Publication number: EP1879677A2
Application number: EP06755175A
Authority: EP
Inventors: Dieter Amesöder; Dieter Schreckenberger; Sven Epli; Michael Thienel; Rainer Loos
Original assignee: Mann and Hummel GmbH
Current assignee: Mann and Hummel GmbH
Priority date: 2005-05-13
Filing date: 2006-05-12
Publication date: 2008-01-23
Also published as: WO2006120241A3; US20080264850A1; WO2006120241A2; BRPI0610810A2; DE202005007872U1; JP2008540913A; AR055788A1; CN101232927A

Abstract

Disclosed is a filter device, especially for filtering liquids in internal combustion engines, comprising a filter element that is to be penetrated in a radial direction and is disposed in a filter housing. A check valve which is embodied as a nozzle valve and is provided with flexible wall sections is inserted into the filter housing. The internal faces of said flexible wall sections define a flow outlet while the external faces thereof are in contact with the liquid in the filter device.

Description

Filter device, in particular for liquid filtration in internal combustion engines

The invention relates to a filter device, in particular for liquid filtration in internal combustion engines, according to the preamble of claim 1.

Document DE 102 48 907 A1 describes a filter device for filtering oil or fuel in internal combustion engines, comprising a filter housing into which a hollow-cylindrical filter element to be flowed through radially can be inserted. In the filter housing between the raw side and the clean side of the filter element, a pressure relief valve is arranged, which is set in the open position, for example, as a result of a soiled filter element, in the open position in the event of an impermissibly high increase in fluid pressure, so that a direct transfer of the to be cleaned Liquid from the raw to the clean side and thus accompanied a pressure reduction on the raw side.

Based on this prior art, the invention is based on the problem to provide a filter device with simple measures, which is particularly suitable for liquid filtration and in which even at an impermissibly high pressure on the raw side of the filter element leakage of oil from the filter housing is prevented , Appropriately, at the same time a good recyclability should be ensured.

This problem is solved according to the invention with the features of claim 1. The dependent claims indicate expedient developments. In the filter device according to the invention, a return check valve is used in the filter housing, via which the filter device, the liquid to be cleaned can be supplied. Under normal conditions, ie at a fluid pressure on the raw side of the filter element below a threshold or limit, the return check valve is in the open position, so that the liquid to be purified can be directed to the raw side of the filter housing. If the pressure on the raw side in front of the filter is greater than on the raw side inside the filter, the valve opens automatically. If, on the other hand, the pressure on the raw side in front of the filter is smaller than on the raw side within the filter, then the valve closes automatically.

The return check valve is designed as a beak valve and has flexible wall sections which define a flow outlet opening. The outside of these wall sections is in contact with the liquid in the filter device, in particular on the raw side of the filter element, so that the wall sections are permanently loaded with the pressure on the raw side, whereas inside the beak valve the flexible wall sections are pressurized from the inside the liquid to be supplied are acted upon. This gives you a self-regulating backflow valve that is automatically closed. For example, an idling of the filter is prevented when the engine of the car is turned off and no oil is conveyed to the filter.

The design as a beak valve is characterized by constructive simplicity combined with high reliability and service life. The beak valve is suitably designed as a one-piece component and consists in particular of plastic, for example an elastomer, whereby a good recyclability is given and the plastic beak valve can be fully ashed especially in a waste incineration. In combination with a filter device whose other components also consist of plastic, you get the best possible recyclability of the entire filter device. Another advantage of the solution according to the invention lies in the relatively small sealing surfaces of the beak valve, whereby the risk of leaks is reduced.

The flow outlet opening of the beak valve is advantageously slot-shaped, wherein the flow slot is bounded by the wall portions of the beak valve. In a preferred embodiment, two cross-flow slots are provided, each bounded by two wall sections of the beak valve. In this way, a total of four offset arranged wall sections, which are each acted upon from the outside with the pressure on the raw side of the filter element, whereby a higher security against unwanted leakage of liquid from the filter device is ensured. But there are also versions with only one slot or with more than two slots into consideration.

The beak valve is to be used with little effort in the housing of the filter device, in particular in a removable cover plate of the filter housing.

This cover disk expediently designed as a one-piece component consists in a preferred embodiment of two individual disks connected to one another via a central flow connection piece, wherein all components of the cover disk are made of plastic. The beak valve is expediently inserted into an opening in the outer single disc of the cover disc, wherein the flow outlet opening of the beak valve advantageously opens into the intermediate space, which lies between the two individual discs and is limited by these. This space communicates with the raw side of the filter element, which lies in particular on the radial outer side of the cylindrical filter element. In addition, this gap can be connected via an overflow or pressure relief valve directly to the clean side of the filter element, in order for the case an inadmissibly high pressure entry on the raw side to allow a direct transfer from the raw to the clean side of the filter element.

Further advantages and expedient embodiments can be taken from the further claims, the description of the figures and the drawings. Show it:

1 shows a section through a filter device for liquid filtration in

Internal combustion engines, with a cup-shaped filter housing, a hollow cylindrical filter element inserted into the filter housing and a two-part cover disk with two individual disks connected via a flow connection,

2 shows the filter device in a perspective view in partial section,

3 shows the cover disc in a perspective view in partial section,

4 shows a section in the region of the internal thread in the flow connection, with a registered elliptical geometry of the thread,

5 shows a filter device in a further embodiment, shown in partial section,

6 is a top view of the filter device of FIG. 5,

7 is a detail enlargement of the detail VII of FIG. 5,

Fig. 8 is a designed as a spill valve spill valve in perspective

View,

9 the beak valve in a view from below, 10 is a perspective view of a support body for a hollow cylindrical filter element, which is placed at one end on a lower end plate, wherein on the end plate, a receiving or attachment piece is formed around the one acting as overflow valve

Sealing tube is placed,

11, the lower end plate in perspective detail view,

12 shows the support body including lower end plate in section,

13a is a perspective view of the support body and the lower end plate in partial section, with an overflow valve in an alternative embodiment,

13b is a view of a similar object as shown in Fig. 13a, but with a spill valve in a further embodiment,

14a, b an overflow or bypass valve, which is used between the raw and the clean side of the filter element, and as the valve body

Elastomer block which can be elastically compressed, shown in the closed position (Fig. 14a) and opening position

(Figure 14b),

15a, b an overflow or bypass valve with an elastomeric bellows as a valve body,

16a, b an overflow or bypass valve with a foam block as a valve body, 17 shows a perspective view of a filter device with a cylindrical filter housing and an annular filter element inserted therein, to which the liquid to be filtered can be supplied via a return check valve,

18 shows a longitudinal section through the filter device according to FIG. 17, including connecting rings inserted at the end,

19 shows the connection rings in individual representation,

20 is an enlarged view of the filter device of FIG. 17 with the return valve designed as a hose valve in the blocking position,

21 is a representation corresponding to FIG. 20, but with the hose valve in the open position, FIG.

22 is a perspective view of another filter device, the one

Lid disc having radially extending spokes.

23 is a perspective view of yet another filter device having an overflow between the raw and clean side, which is provided with axially projecting support legs,

FIG. 24 shows the overflow valve from FIG. 23 in a detail view, FIG.

25 shows a support ring for attachment to the axial end face on the overflow valve, FIG. 26 shows an overflow valve in the cup-shaped filter housing with a mandrel arranged at the bottom of the housing, which protrudes into a recess limited in the overflow valve by the valve housing.

27 is a filter element in plan view,

FIG. 28 shows the filter element according to FIG. 27 in a side view, FIG.

Fig. 29 shows a detail of the filter housing in a perspective view and

Fig. 30, the filter element in the assembled state in the filter housing.

In the figures, the same components are provided with the same reference numerals.

The filter device 1 shown in FIGS. 1 and 2 is used in particular in internal combustion engines for filtering liquids such as oil or fuel. The filter device 1 comprises a plastic filter housing 2, which is approximately cup-shaped and is to be closed by a cover plate 3. In the receiving space in the filter housing 2, a filter element 4 is inserted, which is formed as a hollow cylinder and is supported by a central, arranged in the interior of the filter element 4 supporting body 5 made of plastic. The filter element 4 is flowed through radially from outside to inside, so that the outside of the filter element 4, the crude side 12 and the interior of the filter element forms the clean side 13.

The cover disk 3 is made entirely of plastic and comprises two individual disks 6 and 7, which lie parallel to one another and have approximately the same radius and are connected to one another via a central, hollow-cylindrical flow connection 8. The two individual disks 6 and 7 and the flow pipe 8 form a common, one-piece plastic component, which is produced for example by injection molding or by another method such as deep drawing. Optionally located in the space between the two parallel individual disks 6 and 7 additional connecting webs, over which the two individual disks are supported against each other and the ge, over which the two individual disks are supported on each other and increase the stability of the cover plate 3 considerably.

The central connecting piece 8, which as a constituent part of the cover disk 3 connects the two individual disks 6 and 7, has a connection internal thread 9, via which the cover disk 3 and thus also the entire filter device 1 can be connected to a component of the internal combustion engine , At the same time, the flow nozzle 8 functions as a discharge opening, which communicates with the clean side 13 of the filter element 4 and via which the cleaned liquid is discharged axially from the filter device 1. The flow nozzle 8 extends axially beyond the bottom of the lower, the filter element 4 directly facing disc 7 and a little way into the cylindrical interior of the filter element 4 - the clean side 13 - a.

The lower individual disk 7 is expediently connected directly to the end face of the filter element 4, which is achieved, for example, by means of welding or gluing to the end face of the filter element. In this way, the lower single disc 7 forms the end face of the filter element and on the one hand ensures stability in the filter element and on the other hand for a separation of clean and raw side.

In the upper, the filter element 4 facing away from individual disc 6 inlet openings are introduced, are used in the return check valves 10. These return check valves 10 are formed, for example, as a beak valves, which are shown in detail in Figs. 8 and 9. The liquid to be cleaned is first introduced via the return check valves 10 into the intermediate space between the two individual disks 6 and 7, wherein the return check valves 10 prevent leakage of the liquid when the filter element is removed overhead or, when the engine is switched off, the filter becoming empty. From the space between the individual disks 6 and 7 liquid flows through flow openings 11 in the lower, the filter element 4 directly facing single disk 7 in the raw side 12th a, which is formed as an annular gap between the inner wall of the filter housing 2 and the outside of the filter element 4. After flowing through the filter element 4 in the radial direction from outside to inside, the purified liquid in the central, cylindrical interior (clean side 13) is collected and discharged axially through the flow pipe 8 of the cover disk 3.

On the upper side of the upper individual disk 6 of the cover disk 3, a sealing ring 14 is inserted into a receiving groove provided in the individual disk 6. The sealing ring 14 ensures a fluid-tight connection of the filter device 1 to a component of the internal combustion engine, to which the filter device is connected.

In the lower, the bottom of the filter housing 2 facing region of the filter device, the filter element 4 is sealed by a front end plate 15. This end disk 15, which is located on the end face of the filter element opposite the cover disk 3, has a raised, pot-shaped attachment piece 16, which projects from below into the clean space 13 of the filter element 4. The outside of the rising above the plane of the end plate 15 mounting socket 16 is encompassed by a sealing tube 17 which has the function of a spill valve. In the axially extending walls of the attachment piece 16 recesses 18 are introduced, which are covered by the sealing tube 17 and close the recesses 18 fluid-tight as a rule. If the pressure on the raw side 12 but exceeds a limit and in particular is higher than the pressure on the clean side 13, the purified liquid flows through the bottom of the filter housing 2 from below into the recess in the attachment piece 16 and acts on the recesses 18, the inside of the Sealing tube 17, whereby the sealing tube is radially expanded and the uncleaned liquid can pass directly through the recesses 18 from the raw side 12 to the clean side 13. As the pressure decreases, the recesses 18 are again closed in a flow-tight manner by the residual stress in the sealing tube 17. The sealing tube 17 combines the functions of a component in one component concluded. The sealing tube 17 combines in one component the functions of a valve body and a valve body acting in the closed position valve spring.

In Fig. 3, the cover plate 3 is shown in individual representation. It can be seen that the flow-through openings 11 in the lower individual disk 7 are designed as elongated holes which extend in the circumferential direction of the cover disk. The flow openings 11 are located in the radially outer region of the individual disc 7 and communicate in the installed state of the cover disc 3 directly with the raw side 12 of the filter element.

On the top of the upper single disc 6 is integrally formed with the cover plate, the receiving groove 19 for the inserted sealing ring.

4 shows a section on an enlarged scale through the connecting internal thread 9 in the flow connection 8. The cross-sectional geometry between two adjacent teeth 20 of the thread is elliptical and follows the course shown by the solid line 21. For comparison, a conventional sawtooth geometry known from the prior art is shown with dash-lined line 21 '. The advantage of the elliptical geometry according to the solid line 21 lies in the reduced stresses, which makes it possible to use a relatively soft material such as plastic.

FIGS. 5 to 7 show a further exemplary embodiment of a filter device 1 for liquid filtration. The filter device has an overflow valve 22 in the upper, the cover plate 3 facing region of the filter element 4, which closes under normal conditions an overflow 23 between the raw side 12 and the clean side 13 of the filter element. This overflow opening 23 is introduced into an end plate 26 which is fixedly connected to the upper end face of the filter element 4. The end disk 26 is designed as a separate component, independent of the cover disk 3, but connected to the cover disk. the. In the context of the invention, however, it may also be expedient to connect the lower individual disk 7 of the cover disk 3 directly to the end face of the filter element 4, in which case the overflow opening 23 would be introduced into the individual disk 7. In addition, it is also possible to perform the end plate 26 with the cover plate 3 as a one-piece plastic component.

The overflow valve 22 comprises a closure disk 24, which takes over the function of the valve body and is axially displaceable on the clean side 13 of the filter element and is acted upon by a valve spring 25 in its closed position, in which the closure disk 24 sealingly against the overflow opening 23 in the End disc 26 abuts. The valve spring 25 is supported on the support body 5 of the filter element 4.

The liquid to be purified is introduced via the return check valves 10 into the interior of the filter device; There are a total of four return check valves 10 are arranged in the cover plate 3. If the pressure of the supplied liquid exceeds a limit value, the closure disk 24 is displaced axially downwards out of its closed position against the force of the valve spring 25, whereby a flow path via the overflow opening 23 is released directly from the raw side 12 to the clean side 13. After the pressure has been released, the force of the valve spring 25 is again sufficient to displace the closure disk 24 upward against the applied pressure on the raw side 12 into the closed position, in which the overflow opening 23 is closed in a flow-tight manner. Expediently, all components of the overflow valve 22 are made of plastic, that is to say in particular the closure disk 24 and also the valve spring 25.

FIGS. 8 and 9 show an exemplary embodiment of a non-return valve 10 designed as a beak valve, which is inserted into openings in the cover disk 3 and via which the liquid to be cleaned is fed to the filter device 1. Also, the beak valve 10 is made entirely of plastic. On the outflow side, the beak valve 10 has two cross-flow slots 27 which are open under normal conditions, so that the liquid to be cleaned can pass the beak valve 10. Due to the resilience of the plastic material of the beak valve 10, the wall slits 28 of the return check valve limiting the flow slots 27 can be pressed together to close the flow slits 27 and allow them to pass, acting on the wall sections 28 from outside the liquid through the return check valve 10 is impossible. With decreasing external pressure, the flow slots 27 open again due to the inherent elasticity of the material of the non-return valve 10, so that a flow through the return check valve is made possible again.

FIGS. 10 to 12 show an exemplary embodiment of an overflow valve between the raw and the clean side in the lower, bottom-near section of the filter element. Of the end plate 15, which is located near the ground in the receiving space of the filter housing 2, the central attachment piece 16 rises to the valve body as a cylindrical sealing tube 17 is placed. The central attachment piece 16 comprises vertically rising, mutually separated wall sections 30, which are arranged in a circle around a central elevation 31. The individual wall sections 30 are formed in one piece with the plastic end plate 15 and can elastically spring. This makes it possible to insert a sealing ring 29 in a circumferential groove 32 which is formed on the outside of the wall portions 30.

The valve body forming the sealing tube 17 is inserted into the space between the central cup-shaped elevation 31 and the survey enclosing wall portions 30. The sealing tube in this case closes recesses 18, which are introduced into the walls of the central elevation 31. The uncleaned liquid on the raw side of the filter element enters from below axially into the interior of the central elevation 31 and urges the sealing tube 17 from the inside with pressure radially outward. When a pressure limit on the raw side is exceeded, the sealing tube 17 expands so far that a flow connection is made via the recesses 18 between the raw and the clean side, so that the uncleaned liquid can pass directly to the clean side. With reduction of the pressure on the raw side closes the overflow valve by contracting the sealing tube again independently.

All components of the overflow valve (with the exception of the sealing tube) are made of plastic, which significantly improves the recyclability.

FIG. 13 a shows an overflow valve 22 in the bottom area of the filter element in a further embodiment. Also in this embodiment, all components of the filter element made of plastic. The valve body of the overflow valve 22 is formed by a closure disk 24, which is designed in one piece with snap hook 33, which locked in the interior of the support body 5 at a locking opening of the support body captive, but are held axially displaceable. As a result, the shutter disc 24 can be displaced axially between a closed position in which an overflow opening 23 in the bottom end disk 15 is closed in a flow-tight manner, and an open position. The shutter disk 24 is urged by a valve spring 25 in its closed position.

Under normal conditions, the overflow opening 23, which is framed by the individual wall sections 30 of the attachment stub 16, is closed in a flow-tight manner by the closure disk 24. If the pressure on the raw side exceeds a limit value, the unpurified liquid comes from below via the overflow opening 23 in contact with the closure disk 24 and acts on this with an opening pressure against the force of the valve spring 25, whereby the Lifting disk 24 is raised and a flow connection between raw and clean side is made. With decreasing pressure, the closure plate 24 can again assume the closed position under the action of the valve spring 25, in which the overflow opening 23 is closed.

The spill valve 22 shown in Fig. 13b corresponds in its basic construction to that of Fig. 13a, but with the difference that the valve spring 25 and the snap hook 33 on the valve body are supported directly on the attachment piece 16 and not on the support body 5 of the filter element. The support body 5 is seated on the attachment piece 16, which is suitably connected in one piece with the end plate 15, but may optionally also form a component independent of the end plate 15.

FIGS. 14a to 16b show various exemplary embodiments of overflow valves 22 designed structurally simple, which in the closed position separate the crude side from the clean side in the filter element and, in the open position, allow immediate passage of the unpurified liquid. In a valve housing 34, the valve body formed as a closure disk 24 is arranged axially displaceable and held on a valve spring 25 in the closed position. Acts on the closure disk 24 from the outside a force against the spring force of the valve spring 25, the closure disk 24 in the direction Interior of the valve housing 34 is displaced, whereby overflow openings 23 are released in the wall of the valve housing 34 and a direct flow connection between the raw and clean side of the filter element is created. In the three embodiments shown, the valve spring 25 is designed in each case as an elastically resilient block, wherein in the example of FIG. 14a and 14b, the valve spring 25 is designed as an elastomer block, in Figs. 15a and 15b as Elastomerbalg and in the embodiment of FIG. 16a and 16b as a foam spring block, consisting of PUR foam or silicone foam. FIGS. 17 to 21 show a further exemplary embodiment of a filter device for liquid filtration. The filter device 1 has a cylindrical filter housing 2, in which the annular filter element 4 is received, which is flowed through radially by the liquid to be filtered. For this purpose, the liquid to be cleaned, as shown in Fig. 18, the front side introduced into the filter housing 2. For filtration, the liquid flows through the filter element 4 radially from outside to inside and is then discharged via the interior, which is the clean side, axially from the filter housing again. To support the filter element 4, this has a support frame 5. At the axial end face, via which the liquid is introduced or removed, are concentrically arranged connection rings 40 and 41, which separate the clean room from the raw side. The space between the connection rings 40 and 41 marks the raw side, the interior inside the smaller connection ring 41 the clean side.

As can be seen in the detailed representation of FIGS. 20 and 21, a radially outer support ring 43 is provided on the axial end face, via which the liquid is supplied or discharged, into which radial flow outlet openings 27 are introduced are distributed uniformly over the circumference of the support ring. On the radial outer side of these flow openings 27 are covered by a sealing tube 42, which consists of a flexible, elastic material and is placed under residual stress on the radial outer side of the support ring 43 to cover the flow openings 27. The support ring 43 forms together with the sealing tube 42 designed as a hose valve return check valve 10, which is transferred at a corresponding pressure difference between the radial inside and outside of the sealing tube 42 in the opening position shown in Fig. 21, in which at least portions of the sealing tube 42 from the sealing are lifted off at the flow outlet openings 27 adjacent blocking position, so that a flow can form radially through the flow outlet openings 27. The applied on the inside pressure of the axially brought up, to be cleaned liquid lifts the sealing tube 42 radially from the sealing position, so that the flow outlet openings 27 are released. Once the differential pressure between the inside and outside of the sealing tube falls below a limit that is determined decisively by the inherent elasticity of the sealing tube, the sealing tube again takes its the flow outlet openings occlusive sealing position.

FIG. 22 shows a further exemplary embodiment of a filter device 1 for liquid filtration. The pot-shaped filter housing 2, in which the filter element is received, is closed by an outer cover 6 frontally into which a centric flow port 8 is integrated with internal thread 9. Radial spokes 50 extend between the flow nozzle 8 and a radially outer edge of the individual disk 6. A plurality of such spokes are provided, which are distributed at regular intervals over the circumference of the individual disk 6. The spokes 50 are designed to be rectilinear and expediently extend only in the radial direction. As shown with a dashed design, but it may also be appropriate to provide curved spokes 50 ', which also have a component in the circumferential direction in addition to the radial component. In addition, straight trained spokes are conceivable, which extend at an angle to the radial direction.

In the figures 23 to 25 yet another embodiment of a filter device for liquid filtration is shown. The filter element 4 is annular, wherein the inside represents the clean side and the radial outside of the raw side of the filter. In the region of an axial end face of the filter element 4, an overflow or bypass valve 22 is arranged, which is expediently completely made of plastic and has a valve housing 34 which can be inserted into the axial interior of the filter element 4 in the region of an end face. In the valve housing 34, a valve spring 25 is accommodated, which is designed as a spiral spring and in particular exerts a compressive force. This valve spring 25 acts as a valve body acting shutter disk 24 in the closed position. Ü If the liquid pressure on the raw side exceeds a limit value, the closure disk 24 is opened against the force of the valve spring 25, so that there is a direct flow passage between the raw and the clean side.

In the region of the axial end face, a plurality of supporting feet 60 projecting beyond the axial end face of the filter element 4 are arranged on the valve housing 34, which are expediently formed in one piece with the valve housing 34. These support legs 60 have the function of an elastically resilient support means, whereby upon insertion of the filter element 4 in the filter housing 2, an axial tolerance compensation is achieved when placed on the bottom of the filter housing. Furthermore, the filter element is centered and guided in the housing via the support feet 60. It also ensures that the filter element can not be inadvertently installed upside down.

Suitably, three or four such support legs 60 are arranged distributed on the end face of the valve housing 34 uniformly over the circumference. As can be seen from FIG. 25, it may also be expedient, instead of the support feet, to fasten a support ring 61 to the axial end face of the valve housing 34, wherein the support ring 61 has support elements 62 which act as radially inward and axially opposite the plane of the support ring 61 protruding, thorn-like support springs are formed.

In Fig. 26, another embodiment is shown in which a bypass valve 22 cooperates with a mandrel 70 at the bottom of the cup-shaped filter housing 2. The bypass valve 22 between the raw and the clean side of the filter element to be inserted into the filter element has a valve body forming the closure plate 24 which is subjected to a force of valve spring 25 in its sealing position on the valve housing 34. The valve housing 34 is approximately cup-shaped, wherein the open pot side faces the bottom of the filter housing. The closure disk 24 is at a distance from the bottom of the filter housing, the lateral walls of the valve housing and the closure disk 24 limit a receiving space into which the pin or mandrel 70 protrudes, which is firmly anchored to the bottom of the filter housing.

This mandrel 70 has the task to put the valve body of the bypass valve in the event in the open position, that a wrong filter element including bypass valve is inserted into the filter housing, so that in spite of not prepared for this filter element direct flow connection between raw and clean side and Thus, a flow of the liquid is ensured by the filter device. In particular, when used as a fuel filter emergency supply of the internal combustion engine is ensured with fuel in this way, even if a wrong filter element has been used by mistake.

When correctly used filter element and bypass valve, however, the mandrel only a centering function for the centering of the filter element in the filter bowl, but not an opening function for the bypass valve. In this case, the mandrel protrudes into the recess in the valve housing 34, but without acting on the shutter disk 24 and to adjust to the open position. The shutter disc 24 is in correct insertion or the insertion of the correct filter element even in its closed position with sufficient distance from the tip of the dome.

Another advantage of this dome is that even when using a filter element provided for this purpose accidental insertion of this filter element in the wrong position is prevented. If the filter element is inadvertently inserted upside down into the filter bowl, the front cover disc on the filter element comes into contact with the mandrel 70, so that the filter element is not completely inserted into the filter bowl, which is immediately noticed during mounting. FIG. 27 shows a filter element 4 ^' in plan view. The filter element 4 ^' has an upper end plate 15 ^' , which is formed from a thermoplastic material. The end plate 15 ^' is designed essentially as a circular disk. In this case, a centrally arranged opening 81 is provided, through which the fluid can flow. In other embodiments, the end plate 15 ^'may also be designed only as a circular disk. The opening 81 for the fluid is then arranged on the opposite side. In addition to the circular or circular ring shape, the end plate 15 ^{'can of} course also be embodied as any other basic geometric shape, such as, for example, square, rectangular or polygonal, in particular hexagonal. The end plate 15 ^' has on its circumference three distributed over the circumference arranged key structures 80. Here, the number and distribution of the key structures 80 on the periphery is arbitrary. Therefore, only a single or more than one key structure 80 may be circumferentially arranged. The key structure 80 projects beyond the outer circumference of the end disk 15 ^' with its geometry, wherein the key structure 80 has material webs 82 or gaps 83 of different widths.

The key structure 80 in this embodiment is in the form of the letters "M + H". Of course, all letters in any order and number may be combined to form the key structure 80. Advantageously, the letters are chosen such that they are e.g. a company logo or an abbreviation of company or product names. However, the key structure 80 may also be represented by other characters, such as a. Japanese or Chinese characters or Arabic or Roman numerals are formed.

In Figure 28, the filter element 4 ^{'is shown} in the side view. FIG. 27 corresponding components are provided with the same reference numerals. In addition to the upper end disk 15 ^' and the lower end disk 15, the filter element 4 also has a zigzag folded and annularly closed filter medium 84. The filter medium 84 is sealingly connected to the end disks 15, 15 ^' . In this embodiment, the key structure 80 with its radially over the Circular shape of the end plate 15 ^' projecting portion inclined to the surface of the end plate 15 ^{' is} arranged. Here, the inclination angle α of the key structure 80 is about 45 °. However, the inclination angle α may take any value between 0 ° and 90 °, preferably between 30 ° and 60 °. The key structure 80 engages in a lock structure 85, as shown in the perspective section of the filter housing 2 ^' in FIG.

The lock structure 85 is arranged on the cup-shaped filter housing 2 ^' , which is suitable for receiving the filter element 4 ^' . Here, the lock structure 85 has a negative geometry to the key structure 80, so that the material webs 82 of the key structure 80 engage in gaps 83 of the lock structure 85. The material webs 82 of the lock structure 85 engage in gaps 83 of the key structure 80. The lock structure 85 of the filter housing 2 ^' is formed in this embodiment as a notch in the filter housing wall 86. The notches can both exclude the entire material thickness of the filter housing wall 86, as well as represent only a partial recess. In a partial recess then remains a part of the filter housing wall 86, to which then the key geometry 80 attaches. In other embodiments, the latch structure 85 may be disposed at an angle to the filter housing wall 86 and engage in indentations in the end plate 15 ^' . Due to the interaction of the key-lock structures 80, 85, the structures 80, 85 complement one another. The filter element 4 ^' can thus be used only in the permissible mounting position in the filter housing. An insertion of impermissible filter elements is thus immediately recognizable or prevented when the filter element 4 ^'is not mounted properly. An arrangement of the key structure 80 on the filter housing 2 ^' is of course possible if the associated lock structure 85 is arranged on the filter element 4 ^' .

FIG. 30 shows a filter element 4 ^' according to FIG. 28 in the assembled state in a filter housing 2 ^' according to FIG. 29. The structures 80, 85 of the filter element 4 ^' and the filter housing 2 ^' complement each other such that the filter element 4 ^' is rotationally secure and accurately positioned in the filter housing 2 ^' . This preassembled unit of filter element 4 ^' and filter housing 2 ^' can then in the corresponding receptacle z. B. to a filter head (not shown) or a lid (not shown) are screwed. The described key-lock structures 80, 85 can be arbitrarily combined with the embodiments described above and thus form meaningful embodiments.

Claims

claims

1. Filter device, in particular for filtering liquid in internal combustion engines, with a in a filter housing (2) insertable filter element (4), which is to be flowed through by the liquid introduced into the filter housing, characterized in that in the filter housing (2) a return check valve (10 ), via which the filter device is to be supplied with the liquid to be cleaned, wherein a valve body of the return check valve (10) is formed as a deformable under pressure, flexible sealing portion which sealingly abuts in the blocking position at a flow outlet opening and can be transferred into the open position, when the pressure acting on the sealing portion exceeds a threshold value.

2. Filter device according to claim 1, characterized in that the return check valve (10) is designed as a beak valve and flexible wall sections (28), the inside of which limit a flow outlet opening and the outside of which is in contact with the liquid in the filter device.

3. Filter device according to claim 2, characterized in that the beak valve (10) is designed as a one-piece component.

4. Filter device according to claim 2 or 3, characterized in that the

Beak valve (10) made of plastic, such as an elastomer is made.

5. Filter device according to one of claims 2 to 4, characterized in that the flow outlet opening (27) of the beak valve (10) is slot-shaped.

6. Filter device according to claim 5, characterized in that two cross-flow slots (27) are provided as a flow outlet opening.

7. Filter device according to claim 6, characterized in that the return check valve (10) is designed as a hose valve, wherein the valve body of the hose valve is designed as a sealing tube (42).

8. Filter device according to one of claims 1 to 7, characterized in that the filter housing (2) is closed by a cover disc which consists of two individual discs (6, 7), which are connected to each other via a central flow port (8) the two individual disks (6, 7) and the flow connection (8) are designed as a common plastic component.

9. Filter device according to claim 8, characterized in that in the filter element (4) facing away from the outer single disc (7) of the cover disc (3) at least one in the direction of the filter element (4) opening return check valve (10) is introduced.

10. Filter device according to claim 9, characterized in that in the cover disc (3) a total of four distributed over the circumference arranged return check valves (10) are introduced.

11. Filter device according to claim 9 or 10, characterized in that the flow outlet opening (27) of the return check valve (10) opens into the intermediate space between the two individual disks.