EP1996307A1

EP1996307A1 - Filter insert having a closure for a second filter chamber

Info

Publication number: EP1996307A1
Application number: EP07722077A
Authority: EP
Inventors: Dieter Baumann; Norbert Prinz; Bernhard Batram
Original assignee: Ing Walter Hengst GmbH and Co KG
Current assignee: Ing Walter Hengst GmbH and Co KG
Priority date: 2006-03-20
Filing date: 2007-03-20
Publication date: 2008-12-03
Also published as: WO2007110049A1

Abstract

In a filter insert (22, 25) of a fluid filter (1), in particular an oil or fuel filter, having a filter medium (4, 5) which can be arranged in a filter chamber of the filter, and having at least one end plate (24), the invention proposes that the end plate (24) forms a fluid-tight closure of a second pressure chamber (3).

Description

"Filter insert with closure for second filter chamber"

The invention relates to a filter insert according to the preamble of claim 1.

Such filter cartridges are known in practice. They are used for example in oil filters or in fuel filters of motor vehicles and are interchangeably arranged in a filter housing. The filter housing usually has a

Filter chamber, which is divided by the filter insert in a raw side and a clean side.

In practice, it is often necessary to provide several functional elements in a small space: for example, in the automotive industry two filters that filter the same fluid in a multi-stage filtration, such as. B. as a pre-filter and as the main filter, wherein a fuel filter is provided as a pre-filter between the fuel tank and fuel pump and a main filter between see the fuel delivery pump and the internal combustion engine of the vehicle can be provided. Furthermore, it is common to filter both oil and fuel, so that for this reason two filters, namely for the different fluids, are provided. Furthermore, it may be provided to filter a fluid in both the main and the secondary flow. The invention has for its object to improve a generic filter insert to the effect that this is a compact design of a filter with multiple functional spaces, as well as a time-saving and cost-effective interchangeability of two or more

Functional elements of a filter arrangement allows.

This object is achieved by a filter insert having the features of claim 1.

The filter cartridge is located in a filter chamber, which is referred to in the present proposal as a pressure chamber and which is below a certain internal pressure. The invention proposes that the filter insert located in the first pressure chamber at the same time seals the closure for a second

Pressure chamber forms the same filter assembly. The second pressure chamber may have the same pressure as the first pressure chamber; However, the tightness of the closure can also allow different pressure levels in the two pressure chambers. When removing the filter insert the second pressure chamber is opened so that it is easily accessible, z. B. in the context of regular maintenance, in which anyway the filter cartridge exchanged or cleaned and therefore removed from the filter assembly.

The accessibility to the first pressure chamber is so constructive anyway mandatory. By the proposal according to the same time allowed accessibility to the second pressure chamber, an arrangement of the filter in a confined installation space is made possible, in which arrangement access to the filter from other sites is not possible or only very difficult. Nevertheless, the filter can have a second functional space with a second functional element, without the need for access from a second direction or at a second location on the outside of the filter housing. The filter medium in the one, as a filter chamber signable pressure chamber of the filter is a first so-called functional element, wherein a component is referred to as a functional element in the present proposal, which cooperates with a fluid present in the pressure chamber. For example, a functional element may be present as

^■ a filter element - such. B. a folded filter element made of paper, which serves as an oil or fuel filter,

^■ or as a heating element - such. B. an electric heating coil for heating the cooling liquid,

^■ or as a fluid-permeable, filled with a granule insert - z. B. as an ion exchanger in the cooling liquid or another, for example, for the purification of exhaust gas serving liquid, ^■ or as a separator - such. B. a knitted or Elektroab- separator for separating oil particles from a gas stream of the crankcase ventilation.

In the following, a filter medium as a functional element is often mentioned purely by way of example and representative of other possible embodiments of functional elements.

Advantageously, the second pressure chamber may be formed as a second filter chamber. Also in this application example, the same or different pressure levels prevail in the two pressure chambers. Upon removal of the filter insert, the second filter chamber is opened and allows the same access direction the quick and easy access to a second filter cartridge, so that the change of two filter cartridges after releasing a single lid and a single easily accessible for both filter cartridges access point is possible. Below, by way of example, it is assumed predominantly from the application example that the second pressure chamber is designed as a second filter chamber. Advantageously, the filter element can be fastened to the lid of the filter, so that automatically the filter insert is removed from the filter when the lid is removed and thus handling steps are saved and the time for a filter change is shortened. Advantageously, the filter element with the

Latch locked so that the lid can be reused as a permanent component multiple times and the filter insert can be removed from the filter cartridge by a simple stripping, in which the detents are released.

Advantageously, the second filter element can be fastened to the end disk, so that only one component must be handled for a change of both filter inserts, namely ultimately a single combination filter insert which carries both filter media. To this second filter cartridge from the first

Filter insert, so to be separated from the first filter medium and the end plate, a catch can also be provided here. For example, if different fluids are filtered, so the contaminated with the corresponding residues filter media can be disposed of separately by the second filter cartridge is separated from the end plate of the first filter cartridge by loosening the lock.

Advantageously and in production technology easy to manufacture manner, a collar may be integrally formed on the end plate, which sealingly connects to the second filter chamber. In this case, a concentric arrangement of the filter chambers can be provided in particular advantageous, so that the filter medium carried by the end plate is arranged radially inside or radially outside of the second filter chamber.

The seal to the second filter chamber can be done in a particularly reliable manner, that an elastomeric seal is provided on the collar. Instead of providing this Elastomerdich- direction to the second filter chamber, the seal is in such a configuration with each change of Filter insert also changed so that always optimal sealing properties are ensured.

In a particularly economical way can advantageously form the collar itself the seal. For this purpose, an area with reduced cross-sectional dimensions can be provided on the collar, for example with a tapered circumferential sealing lip, the reduced cross-sectional dimensions ensuring that this area of the end plate acts as a sealing component against the second filter chamber and sealingly abuts it.

As an alternative to the arrangement of two filter cartridges in the two pressure chambers, it may be provided that an oil mist separator is provided at the end disk. That in the second

Pressure chamber guided fluid is in this case a gas stream, for example from the crankcase ventilation of an internal combustion engine.

In this case, the oil mist separator can be designed inexpensively in a conventional manner as a knitted fabric separator.

If the oil mist separator is designed as an electrostatic precipitator, advantageously at least one section of the precipitation electrode of the oil mist separator can be provided on the end plate, so that no space-saving own holder must be provided. In addition, a particularly heavily loaded area of the collecting electrode can be automatically replaced in this way if the filter insert which has the end disk is replaced during regular maintenance work.

In this case, the mentioned part of the oil mist separator can be molded onto the end disk so that the number of components to be produced and assembled can be kept as low as possible when the filter arrangement is produced. Alternatively, the mentioned part of the oil mist separator is releasably connected to the end plate, so that it can continue to be used even with a change of the filter cartridge.

The tightness of the closure can allow different pressure levels in the two pressure chambers. However, it can also deliberately low, so be leaking, so that a desired fluid exchange between the two pressure chambers can take place, even if prevail in both pressure chambers different pressure levels: In particular, when the filter assembly has an oil filter and the aforementioned oil mist separator can be advantageously provided that the end plate has channels serving as flushing channels, which oil - for example, directly from the oil filter - lead as rinsing oil to the Niederschlagselekt- rode. Thus, the collecting electrode can be wetted and the formation of larger particle adhesions at the collecting electrode can be avoided. Such particle buildup could otherwise unduly reduce the relevant distance between the spray and precipitation electrodes of the oil mist separator so that electrical arcing could not be ruled out, which could lead to destruction of the component.

The oil rinse can be done permanently in a particularly economical and easy to produce manner, or it can over a

Control or regulating mechanism - for example, by means of the already provided engine control, or depending on random or regularly changing pressure conditions - be carried out at intervals.

Advantageously, it can be provided that the filter medium has a ring cross-section, and that the closure is arranged on the side facing the filter medium side of the end plate within the ring cross-section. Embodiments of the invention are explained in more detail below with reference to the purely schematic representations. The show

Fig. 1 to 9 different filter cartridges, each in one

Section in the axial direction through a filter assembly having the respective filter assembly.

In the drawings, in which comparable components are each marked with the same reference numerals, a total of one filter arrangement is designated by 1. In Fig. 1, two concentric chambers 2 and 3 are provided, in each of which a filter medium 4 and 5 is arranged. The illustrated filter arrangement is provided as a fuel filter of a motor vehicle. Unfiltered fuel comes from the fuel tank through an inlet port 6 for raw fluid and enters the inner chamber 3. This unfiltered fuel flows through the inner filter medium 5 and enters a collecting space 7 for prefiltered fuel, from which it passes through an outlet opening 8 to the fuel pump.

The fuel delivered by the fuel pump at a higher pressure again enters the filter assembly 1, namely the fuel passes through a pressure fluid inlet 9 in the outer chamber 2, flows through the outer filter medium 4 and leaves the clean side of the outer chamber 2 through a Druckfluidauslass 10th

The two filter media 4 and 5 are designed so that they are permeable to fuel, but not for water contained in the fuel. They therefore also act as water separators and therefore the raw sides of the two chambers 2 and 3 are in each case connected to a water collection chamber 11 and 12, these two water collection chambers 11 and 12 being provided in the lower region of the filter arrangement 1, in a lower housing section 14 who is The outer chamber 2 has at least one drain opening 33 through which water separated on the outer filter medium 4 can pass into the outer water collection chamber 12.

A water level sensor 17 can be used to alert the driver so that he also takes care of the emptying of the water collecting chambers 11 and 12 during the next maintenance to be carried out on his vehicle, or an electric valve 18 can be actuated in dependence on the sensor signal the water from the water collecting chambers 11 and 12 can flow into a larger collecting container, for example when the engine is switched off the next time and the water collecting chambers 11 and 12 are depressurized.

In operation, the pressure prevailing in the outer chamber 2 closes off a schematically indicated check valve 19, which is provided in the outer water collecting chamber 12, so that this outer water collecting chamber 12 is sealed off from the inner water collecting space 11 located at a lower pressure level. If both water collecting chambers 11 and 12 are depressurized, the water in the inner water collecting chamber 11 can flow into the outer water collecting chamber 12 only until the two liquid levels are equal or until the valve 18 is open, the water from both collecting chambers 11 and 12 flows into the outer water collecting chamber 12 12 has drained.

In the exemplary embodiment illustrated in FIG. 1, the filter arrangement 1 has a cover 20 at the upper end of the filter arrangement 1. A radially outer filter insert 22 is latched on the cover 20, this outer filter insert 22 having the outer filter medium 4, which is closed at the bottom by an annular end disk 23 and at the top by a closed end disk 24 which is connected to the cover 20. Having cooperating locking elements. Upon removal of the lid 20 from the upper housing portion 15 is therefore automatically removed and the outer filter insert 22 from the filter assembly 1.

The inner filter medium 5 also has, as part of an inner filter insert 25, a lower annular end disk 26. The upper end disk 24 of the outer filter insert 22 also simultaneously forms an upper end disk of the inner filter medium 5 by the inner filter medium 5 is connected directly to the end plate 24, for. B. welded or glued.

The upper, closed end disk 24 of the outer filter insert 22 has a downwardly directed annular collar 29 with an elastomeric seal 34. Instead of

Elastomeric seal 34 is also a collar of the same material formed sealing lip for sealing used.

The end disk 24 sealingly abuts a partition wall 30, whereby this partition wall 30 separates the chambers 2 and 3 from one another. The central region of the upper end disk 24 therefore represents an upper end of the central, inner chamber 3. When the cover 20 is removed, the outer filter element 22 with its upper closed end disk 24 is removed from the filter arrangement 1 due to the latching. In this case, the inner chamber 3 is opened automatically, which contains the inner filter insert 25.

As a result of the fact that the inner chamber 3 is automatically opened, a separate inner filter insert could now be removed; in the illustrated embodiment, however, it is provided that the inner filter medium 5 also uses the upper end plate 24 as an end plate, that is attached to this end plate 24 so that ultimately only a single component creates both filter cartridges 22 and 25 and the two outer and inner filter media 4 and 5 carries. In order to allow a simple removal of a separate inner filter element 25 in a modification of the illustrated embodiment, this may be connected to the end plate 24 of the outer filter element 22, for example by latching elements similar to those by means of which in the embodiment of FIG. 1, the end plate 24 with the Lid 20 is locked.

Since the removal of both filter media 4 and 5 from the filter assembly 1 from one and the same side, takes place in the same place and through a single opening, this only a very small or narrow accessibility area in the vicinity of the filter assembly 1 is required. This is particularly appropriate if mixing of the two fluids is fundamentally uncritical, as is the case in particular with a two-stage filtration of the same fluid. This is the case, for example, in the case of the two-stage fuel filtration described above, or even a combination of oil filter and oil mist separator, or it could also be the case, for example, if oil were filtered on the one hand in the main flow and on the other hand in the secondary flow.

A central guide tube 31 performs the insertion of the filter insert, the inner filter medium 5 and ensures its orientation during operation, so that the lower end of the inner filter medium 5 with the lower annular end plate 26 can not oscillate freely in operation uncontrollably. The central guide tube 31 is fluid-permeable and / or open at its upper end, so that the passed through the inner filter medium 5

Fluid in the interior of the central guide tube 31, the collection chamber 7 and the outlet opening 8 can pass.

The comparatively long length of the central guide tube 31 forces upon removal of the filter insert 22 that the

Lid 20 together with the two filter media 4 located thereon and 5 must be withdrawn axially from the filter assembly 1 over a comparatively long length. This assists that the two filter media 4 and 5 can drip off, so that one is less likely by mixing the two fluids than with an unguided, freely movable lid

20 with attached dirty filter media 4 and 5.

The size of the two Wasserammeiräume 11 and 12 is purely exemplary. In particular, when used as a two-stage fuel filter, for example before and after the fuel delivery pump, it can be provided that in the region of the prefiltration, ie in the region of the inner chamber 3, the water collection chamber 11 for the separated water is significantly larger than in the region of Filtration on the fuel pump, because it can be assumed that a significant majority of the amount of water contained in the fuel already in the first water separation stage, ie in the field of prefiltration of the fuel can be deposited.

The lower housing portion 14 may be made of a transparent

Material have or have transparent portions, so that regardless of the illustrated water level sensor 17, an optical level control of the outer Wasserammeiraums 12 is possible.

The Wasserammeiräume 11 and 12 may be particularly advantageously designed both equally visible. This can take place, for example, in that the outer water collecting space 12 does not extend over the entire circumference of the lower housing section 14 but, for example, only over half or three quarters of the circumference, so that in the remaining section a free view of the radial further inside the inner water collecting chamber 11 is made possible. In this respect, depending on the size of such a cutout in the illustrated cross-sectional dimensions of the inner Water collecting 11 have a larger receiving volume than the outer Wasserammeiraum 12th

Deviating from the embodiment shown in FIG. 1, however, it may also be provided that the inner filter medium 5 is part of a separate inner filter insert, which has its own upper end disk, which is arranged above or below the end disk 24.

Fig. 2 shows such a filter assembly 1, which serves as a fuel filter and in which the inner filter medium 5 is part of a separate inner filter cartridge 25 having its own upper end plate. In her deviating from the embodiment shown in Fig. 1 is also provided that a constant contact of the filter media 4 and 5 is excluded with the separated water. For this purpose, the filter media 4 and 5 are both dimensioned so short, or the water collection chambers 11, 12 combined into a common water collecting space are provided correspondingly far down in the filter arrangement 1. In this way, also inexpensive

Filter media find use that could otherwise soften, in constant contact with water, such as paper filter media. The passage openings and the fluid flow of the separated water is indicated schematically by the arrows pointing downwards, which lead from the two chambers 2 and 3 of the filter arrangement 1 into the common water collecting space

In addition, a comparatively large embodiment is shown with reference to FIG. 2, in which only the lower water collecting space has a capacity of more than 1 liter. Due to the large length of the housing, the partition wall 30 is advantageously produced in terms of production as screwed into the rest of the filter housing component by the partition wall 30 is provided at its lower end with a thread. Furthermore, the embodiment of FIG. 2 shows that the partition wall 30 forms a support dome for the outer filter medium 4 of the outer filter insert 22. Under the pressure, temperature and flow conditions prevailing during operation, the filter medium 4, which flows radially from outside to inside, contacts the support dome and is prevented from collapsing by it without the outer filter element 22 having the outer filter medium 4 itself should have appropriate strength.

The upper end plate 24 in this embodiment consists of two parts which are firmly connected by gluing or welding. Notwithstanding the illustrated embodiment, the two parts, which together form the upper end plate 24, could be sealed against each other by means of a seal.

A permanent venting of the fuel via a central vent pipe 35. This has several inlet openings for the air, and at its upper end an air outlet nozzle. The inlet openings and / or the air outlet nozzle have a small inner diameter, so that a resistance for the fuel is given, which helps to avoid undesirable high circulation losses, but the discharge air can flow through almost unhindered.

FIG. 3 shows an outer, annular filter insert 22, within which an oil mist separator in the form of an electrostatic precipitator 40 is arranged. The upper end disk 24 of the filter insert 22 forms a portion 41 of a collecting electrode 42 of the electrostatic precipitator 40. The fact that this section 41 is regularly replaced together with the filter element 22 in the context of regular maintenance work, prevents deposits can build up inside of the collecting electrode 42, the otherwise insbeson- These could lead to electric flashovers around the corona region 44, which could lead to failure or destruction of the electrostatic precipitator 40.

The collecting electrode 42 surrounds the inner pressure chamber

3, in which a spray electrode 43 is arranged, and thus forms a comparable with the partition wall 30 of FIG. 1 separation between the two pressure chambers 2 and 3. The spray electrode 43 is at its front end, which is hit by a gas flow first as an approximately needle-shaped corona area

44 designed. The gas stream of the venting gas containing oil particles flowing from the crankcase passes through a blow-by gas inlet 48 into the filter assembly 1 and through a window 45 into the inner pressure chamber 3 and exits through a clean gas outlet 46. Separate oil flows down the collecting electrode 42 and is guided out of the filter assembly 1 through an oil outlet 47.

Similar to FIG. 3, FIG. 4 shows an outer filter insert 22, within which an electrostatic precipitator 40 is arranged as an oil mist separator. The gas enters from above, as indicated by an arrow; by an upper central gas inlet nozzle, which is provided in an upper screw cap. At this gas inlet nozzle and at a lower nozzle at the clean oil outlet of the outer chamber 2 of the filter cartridge 22 is located with annular seals, which are indicated purely by way of example with a round cross-section, so for example as O-ring seals can be performed.

The precipitation electrode 42 of the electrostatic precipitator 40 is designed as an integral part of the filter housing and thus as a so-called lifetime component. The spray electrode 43 can be removed downwardly from the filter housing. The precipitation electrode 42 also surrounds the inner pressure chamber 3 in this exemplary embodiment, but differs from the partition wall 30 of FIG. 1 in that it is a conscious one allows fluid-permeable connection between the two pressure chambers: the two pressure chambers 2 and 3 are interconnected by flow channels 49.

The flow channels 49 are arranged distributed around the collecting electrode 42 around. Due to the higher pressure level in the outer pressure chamber 2, oil is conducted from the oil filter provided there through the flow channels 49 into the inner pressure chamber 3, where it wets the inner surface of the precipitation electrode 42 and flows downwardly therefrom. This permanent cleaning of the inner surface of the collecting electrode 42 prevents the formation of deposits on the inner collecting electrode 42, which otherwise could lead to electric flashovers around the corona region 44, which could lead to electrical shocks

Function failure or destruction of the electrostatic precipitator 40 could lead.

In the embodiment of FIG. 5, the upper end plate 24 of the outer filter insert 22 forms similar to the

Embodiment of FIG. 1, a collar 29, so that the inner chamber 3 is closed at the top by the upper end plate 24 of the outer filter element 22. In contrast to the embodiment of FIG. 1, the inner filter medium 5 is not held on the upper end plate 24, but is taken down from the filter assembly 1 by means of a lower lid 21st

In the embodiment of FIG. 6 is also an embodiment of the filter assembly 1 with two opposite

Lids 20 and 21 are provided and an embodiment of the collar 29 at the upper closed end disk 24 of the radially outer filter insert 22. The inner filter medium 5 is not attached directly to this end plate 24, for example by gluing or fusion, as provided for the outer filter medium 4 can be, but the inner filter medium 5 is designed as part of a separate, inner filter insert 25 with two end disks. An upper end disk 27 of the inner filter insert 25 is detachably fastened to the upper end disk 24 of the outer filter insert 22 by means of latching elements.

In the embodiment of FIG. 7, similar to the embodiment of FIG. 1, it is provided that both filter media 4 and 5 are fastened to the upper end disk 24. However, FIG. 7 shows a variant embodiment with two opposite housing covers 20 and 21, so that the longer, radially inwardly provided filter area of the inner chamber 3 is optimally accessible over its entire length, for example for maintenance work, namely in its lower area from the lower cover 21 ago.

The different configuration of the upper and lower housing sections 14 and 15, for example with only a one-sided lid, which opens access to both chambers 2 and 3, or with two opposite lids 20 and 21 may be advantageous for production reasons, depending on the specific detail design and division of the individual housing sections 14 and 15 and arrangement of the individual chambers 2 and 3:

By means of corresponding core tools of an injection-molded tool, which are pulled in different directions, an embodiment of the housing sections 14 and 15 can be achieved in which the conicalities of the individual components required for demolding the housing components from the injection mold

Walls lead to the most uniform wall thicknesses, and not about wall thicknesses, which must be particularly thick at one point for manufacturing reasons, with these particularly large wall cross-sections are disadvantageous in terms of material costs, but also in terms of Problems of volumetric shrinkage and resulting sink marks, which would possibly lead to leaks, for example, if such areas of accumulations of material occur in a sealing area.

In the embodiment of Fig. 8, an outer filter medium 4 is shown as an outer functional element. As an inner functional element, an electrostatic precipitator 40 is provided, comprising a precipitation electrode 42 and a spray electrode 43, which has a needle-shaped corona region 44 in its foremost region, on which a fluid flow first impinges.

Upon removal of the cover 20 from the upper housing portion 15, the upper end plate 24 is also removed from the upper housing portion 15 due to locking elements 28, so that the outer filter insert 22 can be removed from the housing. In this case, the collecting electrode 42 remains with a lower, so in the flow direction rear portion 50 as a fixed component in the filter assembly 1. An upper, ie in the flow direction front portion 51, however, is designed as a separate component and molded to the upper end plate 24 and is the so-called filter change When the filter cartridge 22 is removed and a new filter cartridge 22 is used, it is also automatically replaced. Even without specially provided cleaning possibilities of the collecting electrode 42, regular replacement of the collecting electrode 42, which is particularly stressed in the corona region, ensures that deposits can not accumulate to an impermissible extent on the inner surface of the collecting electrode 42 until, if appropriate, the Functioning of the

Elektroabscheiders 40 would be at risk.

In Fig. 9, a filter assembly 1 is shown, in which similar to Fig. 1, the two filter media 4 and 5 are fixedly connected to the upper end plate 24. However, the upper end plate 24 is not different from the embodiment of FIG. 1 is not closed, but provided annularly and with a central opening through which a central ventilation fist 35 extends similar to in Fig. 2. The upper end plate 24 is sealed by means of an elastomeric seal against the central vent tube 35.

Leading from both chambers 2 and 3 flow channels lead to a common for both chambers 2 and 3 Wasserammeiraum 11. Similarly as by means of the check valve 19 in the embodiment of Fig. 1 can be provided that the flow channels via a - in FIG 9 not shown - Valve optionally separated from each other or connected to each other. At 52, the connection of a manual feed pump is shown, since the filter assembly 1 is designed as a fuel filter for a vehicle, which has no electric fuel pump, so that after maintenance of the interior of the filter assembly 1 can be manually filled. At 53, a connection of a heater is shown, which is provided for preheating the fuel.

If only a comparatively small installation space for the fuel filter is available and a comparatively large volume flow is to flow through the filter arrangement, a water collection chamber may possibly be dispensed with. This is especially possible if the filter media allow water particles to be entrained with the fuel through the filter surface.

Claims

claims:

1. filter insert of a fluid filter, in particular an oil or fuel filter, with a filter chamber can be arranged in a filter medium, and with at least one end plate, characterized in that the end plate (24) forms a fluid-tight closure of a second pressure chamber.

2. Filter insert according to claim 1, characterized by provided on the end plate (24) latching means for fastening the filter insert (22) on a cover (20) of the filter.

3. Filter insert according to claim 1 or 2, characterized in that a second filter chamber (3) forms the second pressure chamber.

4. Filter insert according to one of the preceding claims, characterized in that a second functional element with the end plate (24) is connected.

5. Filter insert according to claim 4, characterized in that the second functional element is designed as a filter insert.

6. Filter insert according to claim 4, characterized in that the second functional element is designed as a component of a separator.

7. Filter element according to claim 4, characterized in that the separator is designed as an oil mist separator.

8. Filter insert according to claim 6 or 7, characterized in that the second functional element forms at least a portion of a collecting electrode of an electrostatic precipitator.

9. Filter insert according to claim 6 or 7, characterized in that the oil mist separator is designed as a knitted separator.

10. Filter insert according to one of claims 4 to 9, characterized in that the second functional element is releasably connected to the end plate.

11. Filter insert according to claim 4, characterized in that the second functional element to the end plate (24) is integrally formed.

12. Filter insert according to one of the preceding claims, characterized by a to the end plate (24) molded collar (29), which adjoins the second pressure chamber.

13. Filter insert according to claim 12, characterized by a collar (29) arranged elastomeric seal (34).

14. Filter insert according to claim 13, characterized in that the collar (29) of the same material forms a designed as a seal area with reduced cross-sectional dimensions.

15. Filter insert according to one of claims 6 to 8, characterized in that the two pressure chambers are connected by flushing channels, which lead oil to the collecting electrode of an electrostatic precipitator.

16. Filter element according to claim 15, characterized in that the end plate (24) has the flushing channels (49).

17. Filter element according to one of the preceding claims, characterized in that the filter medium a

Has annular cross-section, and that the closure is disposed on the side facing the filter medium side of the end plate within the annular cross-section.