Filter equipment, in particular fuel or lubrication filters and water separators

Abstract

Filtering device (1), in particular fuel filter or lubrication filter, - with a filter housing (2), - with a ring filter insert (3) arranged in the filter housing (2) and comprising a filter medium (4), - with a water separator (6) arranged in the filter housing (2), preferably below the ring filter insert (3), which has a through-opening (7) through which a mounting sleeve (5) arranged in the filter housing (2) passes, - wherein the water separator (6) has a hydrophobic membrane (13) that is permeable to fuels and lubricants and separates a raw side (14) of the water separator (6) from a clean side (15), - wherein the water separator (6) comprises a bypass device (16) which provides a fluid connection between the raw side (14) and the clean side (15) by bypassing the membrane (13), characterized in that - the water separator (6) is designed in a pot-like shape and comprises a pot base (10) from which a pot collar (11) projects radially outwards, on which the membrane (13) of the water separator (6) is arranged, - the pot base (10) is ring-shaped and surrounds the through-opening (7) through which the fastening sleeve (5) extends, - the pot base (10) for sealing the raw side (14) against the clean side (15) comprises a sealing device (17) enclosing the through-opening (7) and supported on the mounting stud (5), - the bypass device (16) is part of the sealing device (17).

Description

[0001] The invention relates to a filter device, in particular a fuel or lubrication filter, with a water separator and a water separator for a filter device.

[0002] Filter systems, especially fuel and lubricant filters, are used in modern motor vehicles and serve to clean the fuels and lubricants required to operate the vehicle's internal combustion engine. All conventional fuels and lubricants contain a small amount of water, which impairs the effectiveness of the fuel and lubricant and increases the risk of corrosion for the internal combustion engine.

[0003] For this reason, conventional filter systems use so-called water separators, which attempt to reduce the water content as much as possible by separating the water present in the fuel or lubricant. Such water separators typically comprise a membrane that is permeable to the fuel or lubricant but hydrophobic, allowing the fuel or lubricant to pass from the raw side of the water separator through the membrane into the clean side. In contrast, the separated water remains in the raw side and is collected there.

[0004] Against this background, EP 2 331 229 B1 discloses a filter device for an internal combustion engine with a water separator having a hydrophobic membrane permeable to fuel or lubricant. The water separator is arranged axially beneath a filter element for filtering out dirt particles from the fuel or lubricant, creating a sedimentation chamber which, in conjunction with the hydrophobic membrane, ensures that any water contained in the fuel or lubricant can be almost completely filtered out.

[0005] DE 10 2015 003 756 A1 deals with a filter device with a bypass and with a water separator that includes a water separating sieve.

[0006] During operation of the filter system, especially when using diesel fuel, the fuel or lubricant can gel at cold ambient temperatures. This causes the fuel or lubricant to become waxy and viscous, making filtration through the filter medium more difficult. This can also result in an increased pressure drop between the raw and clean sides of the water separator, which can damage or even destroy the water separator's membrane.

[0007] It is an object of the present invention to provide an improved filter device in which the above-mentioned problem is eliminated and, in particular, the risk of damage to the water separator is reduced or even completely eliminated.

[0008] This object is achieved by a filter device according to independent claim 1. Preferred embodiments are the subject of the dependent claims.

[0009] The basic idea of ​​the invention is therefore to integrate a bypass device into the water separator of a filter device, which follows the operating principle of a bypass valve. The bypass device is designed in such a way that in the event of a fault, i.e. if an excessive pressure difference occurs between the raw side and the clean side of the water separator, it establishes a direct fluid connection between the raw and clean sides, by means of which the hydrophobic membrane, which is permeable to fuel or lubricant, can be bypassed. This state of the bypass device corresponds to an open bypass valve. In the event of a fault, the fuel or lubricant can flow from the raw side to the clean side, bypassing the membrane, whereby the resulting pressure difference can be reduced without damaging or even destroying the membrane.If the resulting fault condition is resolved by pressure equalization between the raw and clean sides, allowing the filter device to operate in its nominal operating state again, the fluid connection is interrupted again. As a result, the fuel or lubricant can flow exclusively through the membrane from the raw side to the clean side, as desired during nominal operation of the filter device. This state of the bypass device corresponds to a closed bypass valve. As a result, damage to the sensitive membrane in fault situations can be avoided by means of the water separator designed according to the invention.

[0010] A filter device according to the invention comprises a filter housing with an annular filter insert arranged in the filter housing and comprising a filter medium. The filter housing can have a substantially cylindrical geometric shape. Fuel or lubricant can flow through the annular filter insert radially from the outside to the inside. Dirt particles present in the fuel or lubricant can be separated by means of the filter medium. A water separator is arranged in the filter housing, preferably below the annular filter insert. The position "below" refers to a position of use of the filter device. The water separator has a through-opening through which a member arranged in the filter housing passes and is thus fixed to the mounting socket.The water separator is equipped with a membrane that is permeable to fuels and lubricants, yet hydrophobic, i.e., impermeable to water, and which separates a raw side from a clean side of the water separator. According to the invention, the water separator comprises a bypass device that provides a fluid connection between the raw side and the clean side, bypassing the membrane. According to the invention, the water separator is pot-shaped and has a pot base from which a pot collar protrudes radially outward, on which the membrane of the water separator is arranged. The pot base is annular and encloses the through-opening through which the mounting nozzle passes. In this variant, the pot base comprises a sealing device to seal the raw side from the clean side. This sealing device encloses the through-opening of the water separator and is supported on the mounting nozzle.This prevents fuel or lubricant from leaking from the raw side through the gaps between the pot base and the mounting nozzle into the clean side during nominal operation of the filter system. In this variant, the bypass device is part of the sealing device. This means that a mechanism is integrated into the sealing device that, when the filter system is operating outside of its nominal operating conditions—typically when the pressure difference between the raw and clean sides mentioned above—at least temporarily cancels the sealing effect of the sealing device.

[0011] In a preferred embodiment, the bypass device is designed as a bypass valve. Said bypass valve is adjustable, depending on at least one parameter, between an open state, in which the fluid connection between the raw side and the clean side is established, and a closed state, in which this fluid connection is eliminated. In this way, in the event of a fault, for example, if the pressure difference between the raw and clean sides is too high, the flow of fuel or lubricant through the membrane can be prevented.

[0012] Therefore, the at least one parameter is expediently a pressure difference between the raw and clean sides of the fuel or lubricant flowing through the water separator. This can prevent an excessive pressure difference between the raw and clean sides. Alternatively, the at least one parameter can be the temperature of the fuel or lubricant flowing through the water separator. Since gelling of the fuel or lubricant occurs at low temperatures, this can also prevent damage or even destruction to the membrane.

[0013] In an advantageous further development, the sealing device is designed as a sealing lip made of an elastic material. Such sealing lips are comparatively simple in design and therefore inexpensive. Furthermore, they are well suited for the integration of the bypass device, as will be explained below.

[0014] In an advantageous further development, the sealing lip is curved in a longitudinal section of the filter device along its axial direction toward the ring filter insert. This measure reinforces the aforementioned advantageous effect.

[0015] If the bypass function of the bypass device is to be deactivated during nominal operation of the filter device, a further preferred embodiment recommends designing the sealing device, in particular the sealing lip, such that it is pre-tensioned against the mounting socket. This achieves a particularly good sealing effect.

[0016] In another preferred embodiment, the sealing device, preferably the sealing lip, is designed such that it is moved away from the mounting nozzle when a predetermined threshold differential pressure of the fuel or lubricant flowing through the water separator between the raw side and the clean side is exceeded. The sealing device or sealing element is designed such that a direct fluid connection is established between the raw side and the clean side through the resulting gap between the sealing device and the mounting nozzle. As soon as the pressure drops below said threshold differential pressure, the sealing device is returned to its original state, so that said fluid connection is eliminated. The filter device is then back in its nominal operating state. The variant presented here also includes hysteresis effects, i.e.The differential threshold pressure can have a different value when the differential pressure increases than when the differential pressure decreases.

[0017] Particularly expediently, the bypass device can be designed as at least one recess in the sealing device, by means of which a direct fluid connection between the raw side and the clean side is created, bypassing the membrane. The formation of one or more recesses in the sealing device is technically very simple to implement and thus particularly cost-effective. This is especially true when the sealing device is implemented as a sealing lip. Furthermore, such a simple design of the bypass device ensures reliable operation of the entire filter device.

[0018] Particularly preferably, the recess can be designed as a through-gap or through-slot. Such a gap-like or slot-like geometry can ensure, on the one hand, that the sealing device seals the raw side from the clean side in the nominal operating state, and, on the other hand, that the bypass function essential to the invention is activated in the event of a fault by temporarily suspending the sealing effect of the sealing device.

[0019] In an advantageous further development, said recess, in particular when it is designed as a through-gap or as a through-slot, extends with respect to a plan view of the annular pot base along the axial direction of the filter housing in the radial direction of the water separator.

[0020] In a further advantageous development, the bypass device comprises at least two recesses, preferably a plurality of recesses, which are arranged at a distance from one another along a circumferential direction of the sealing device, preferably the sealing lip. In this way, the effect of the bypass function provided by the recesses can be doubled or multiplied. The desired sealing effect during nominal operation of the filter device can be particularly well ensured if the recesses are arranged equidistant from one another in the circumferential direction.

[0021] Particularly preferably, the at least one recess forming the bypass device is adjustable between an open and a closed state. In the open state, the recess provides the desired fluid connection between the raw side and the clean side. In the closed state, this fluid connection is eliminated. The closed state is therefore associated with the nominal operating state. The open state, on the other hand, is associated with the fault situation.

[0022] To achieve adjustability between the open and closed states, an advantageous refinement proposes defining the material of the sealing device in the area of ​​the recess and, alternatively or additionally, the geometry of the recess in such a way that the recess can be closed by thermal expansion of the material. Since the aforementioned gelling of the fuel or lubricant occurs at low temperatures, the desired bypass function can be activated at sufficiently low temperatures by thermal contraction of the material and the associated opening of the recess.

[0023] Particularly preferably, the material of the sealing device can be or comprise an elastomer. Such elastomers meet the material requirements required for the implementation of the bypass function of the bypass device.

[0024] Particularly preferably, the pot base and the sealing device, preferably the sealing lip, are made of the same material. This measure further simplifies the construction of the filter device.

[0025] In an advantageous further development, the sealing device, preferably the sealing lip, is formed integrally on the pot base. Compared to a separate design of the sealing device or sealing lip, this variant is associated with particularly low manufacturing costs.

[0026] Particularly advantageously, the through-passage gap or through-passage slot can have a gap or through-passage slot width of no more than 1 mm, preferably no more than 0.7 mm. In this way, the desired valve effect of the bypass device can be achieved with comparatively little technical effort.

[0027] In another preferred embodiment, at least one through-opening, preferably a plurality of through-openings, is arranged in a peripheral wall of the fastening nozzle, via which water separated in the raw side can be collected and / or discharged.

[0028] The invention further relates to a water separator for a filter device, in particular for a filter device as described above. The water separator comprises a hydrophobic membrane that is permeable to fuels and lubricants and separates a raw side of the water separator from a clean side. The water separator further comprises a bypass device that provides a fluid connection between the raw side and the clean side, bypassing the membrane. The water separator is pot-shaped and comprises an annular pot base that encloses a through-opening.

[0029] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

[0030] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0031] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0032] They show, schematically: Fig. 1 a first example of a filter device according to the invention, Fig. 2 the water separator of the filter device according to Fig. 1 in a separate representation, Fig. 3 a detailed representation of the Fig. 2, which shows the bypass device. Fig. 4 a variant of the example of Fig. 1 to 3.

[0033] Fig. Figure 1 illustrates a first example of a filter device 1 according to the invention, through which fuel or lubricant can flow. The flow path of the fuel or lubricant is shown in Fig. 1 is indicated by an arrow labeled "K". The filter device 1 comprises a filter housing 2. Arranged in the filter housing 2 is an annular filter insert 3 which comprises a filter medium 4 for filtering the lubricant or fuel flowing through the filter device 1. The fuel or lubricant flows through the filter medium 4 in the radial direction of the filter housing 2 from a raw side 8 of the annular filter to a clean side 9 of the annular filter. Furthermore, a mounting socket 5 is arranged in the filter housing 2, to which the annular filter insert 3 is attached. Like the filter housing 2, the mounting socket 5 has a cylindrical geometric shape.

[0034] How Fig. As can be further seen in Figure 1, a water separator 6 is arranged in the filter housing 2 axially below the ring filter insert 3. The position "below" refers to a use of the filter device 1 during nominal operation in a motor vehicle. In an alternative variant not shown, the water separator 6 can also be arranged in the ring filter insert 3 in the ring filter clean side 9.

[0035] The Fig. 2 shows the water separator 6 of the Fig. 1 in a separate, perspective view. According to Fig. 2, the water separator 6 is pot-shaped and comprises a pot base 10. A pot collar 11 protrudes radially outward at an angle from the pot base 10. The pot base 10 is ring-shaped and encloses a through-opening 7 through which the fastening piece 5 passes (cf. Fig. 1).

[0036] The cup collar 11 can comprise a plurality of support elements 12 formed integrally on the cup base 10 and arranged equidistantly from one another along a circumferential direction U of the cup base 10, each of which is designed in the manner of a strut. Arranged radially outside on the support elements 12 is a hydrophobic, i.e., water-impermeable, membrane 13 that is continuous for fuels and lubricants and through which flow can occur in the radial direction of the filter housing 2 from a raw side 14 of the water separator 6 to a clean side 15 of the water separator 6. The membrane 13 thus separates the raw side 14 from the clean side 15. The membrane 13 thus forms the cup collar 11. The pot base 10 comprises a sealing device 17 for sealing the raw side 14 of the water separator 6 against its clean side 15. The sealing device 17 encloses the through opening 7 and is supported on the fastening nozzle 5. The sealing device 17 ensures that fuel orDuring nominal operation of the filter device 1, lubricant can only pass through the membrane 13 from the dirty side 14 to the clean side 15. The sealing device 17 can be designed as a sealing lip 18, preferably made of an elastic material. The sealing device 17, designed as a sealing lip 18 in the example scenario, is preloaded against the mounting socket 5.

[0037] How Fig. 1, the sealing lip 18 can be curved in a longitudinal section of the filter device 1 or the filter housing 2 along the axial direction A towards the ring filter insert 3.

[0038] The water separator 6 further comprises a bypass device 16, which provides a fluid connection between the raw side 14 and the clean side 15, bypassing the membrane 13. The bypass device 16 is designed in the manner of a bypass valve. Said bypass valve is adjustable, depending on at least one parameter, between an open state, in which the fluid connection between the raw side 14 and the clean side 15 is provided, and a closed state, in which this fluid connection is canceled. In this way, in the event of a fault, the flow of fuel or lubricant through the membrane 13 can be prevented. Advantageously, the at least one parameter is a pressure difference built up between the raw side 14 and the clean side 15 of the fuel or lubricant flowing through the water separator 6. In this way, an excessive pressure difference between the raw and clean sides can be avoided.Alternatively, the at least one parameter can be the temperature of the fuel or lubricant flowing through the water separator 6. Since the gelling of the fuel or lubricant occurs at low temperatures, damage or even destruction of the membrane 13 can also be avoided in this way.

[0039] In the example of the figures, the bypass device 16 is part of the sealing device 17. The bypass device 16 comprises a plurality of recesses 19 formed in the sealing lip 18, by means of which a direct fluid connection is created between the raw side 14 and the clean side 15, bypassing the membrane 13. Preferably, the recesses 19 are each designed as a through-pass gap 20 or as a through-pass slot, which preferably have a gap or slot width of at most 1 mm, most preferably of at most 0.7 mm.

[0040] The recesses 19 designed as a through gap 20 or through slot extend, with respect to a plan view in the axial direction A, onto the annular pot base 10 of the water separator 6 along its radial direction R.

[0041] In the example scenario, the bypass device 16 comprises four recesses 19, which are arranged at a distance from one another along a circumferential direction U of the sealing lip 18, wherein the angular distance between two recesses 19 adjacent in the circumferential direction U is equidistant. It is clear that in variants of the example, a different number of recesses 19 can also be provided.

[0042] The recesses 19 are adjustable between an open state, in which they provide the desired fluid connection between the raw side 14 and the clean side 15 in the event of a fault, and a closed state in which this fluid connection is eliminated.

[0043] To achieve the desired adjustability between the open and closed states, the material of the sealing device 17, implemented as a sealing lip 18, in the area of ​​the recesses 19, as well as the geometry of the recesses 19 – in the example scenario, a gap- or slot-like geometry is selected – are determined in such a way that the recesses 19 can be closed by thermal expansion of the material, similar to a bypass valve. The gelling of the fuel or lubricant mentioned above, which causes the fault condition, typically occurs at low temperatures, such as those that occur immediately after commissioning of the filter device. This condition corresponds to an open bypass valve. Therefore, with this variant, the recesses forming a bypass actually form the aforementioned fluid connection between the raw and clean sides only at correspondingly low temperatures.At high temperatures, such as those encountered during nominal operation of the filter device, the thermal expansion of the material of the sealing lip 18 compared to low temperatures causes the recesses to close, essentially disappearing. This state corresponds to a closed bypass valve.

[0044] An elastomer can be used as the material for the sealing device 17 or sealing lip 18. The pot base 10 and the sealing device 17 implemented as a sealing lip 18 can be made of the same material. Thus, an elastomer can also be considered as the material for the pot base 10. Particularly expediently, the sealing device 17 implemented as a sealing lip 18 can be formed integrally on the pot base 10.

[0045] Fig. 4 shows as a second example a variant of the first example of the Fig. 1 to 3. In the example of Fig. 4 are missing the Fig. 2 and Fig. 3 explained recesses. In the example of Fig. 4, the sealing device 17, which is implemented as a sealing lip 18, is designed such that, when a predetermined threshold differential pressure of the fuel or lubricant flowing through the water separator 6 between the raw side 14 and the clean side 15 is exceeded, it moves away from the fastening nozzle 5 (cf. arrow 22 in Fig. 4). In this way, in the event of a fault, a direct fluid connection can be established between the raw side 14 and the clean side 15 of the water separator 6 through the resulting gap 21 between the sealing device 17 and the fastening nozzle 5. The sealing device 17 or sealing lip 18 is in Fig. 4 in a state in which such a gap 21 is formed, additionally shown and designated 17' or 18'.

[0046] The variant according to Fig. 4 can be illustrated with the example of Fig. 1 to 3. In this case, the sealing lip 18 is provided with Fig. 4 also based on the Fig. 2 and Fig. 3 explained recesses 19 are present.

[0047] How Fig. 1, through openings 24 can be arranged in a peripheral wall 23 of the fastening nozzle 5, via which water separated in the raw side 14 can be collected and / or discharged from the filter housing 2.

Claims

[1] Filter device (1), in particular fuel filter or lubrication filter, - with a filter housing (2), - with a ring filter insert (3) arranged in the filter housing (2) and having a filter medium (4), - with a water separator (6) arranged in the filter housing (2), preferably below the ring filter insert (3), which has a through-opening (7) through which a fastening piece (5) arranged in the filter housing (2) passes, - wherein the water separator (6) has a hydrophobic membrane (13) which is permeable to fuels and lubricants and separates a raw side (14) of the water separator (6) from a clean side (15), - wherein the water separator (6) comprises a bypass device (16) which provides a fluid connection between the raw side (14) and the clean side (15) bypassing the membrane (13), characterized by , that - the water separator (6) is pot-shaped and comprises a pot base (10) from which a pot collar (11) protrudes radially outwards, on which the membrane (13) of the water separator (6) is arranged, - the pot base (10) is ring-shaped and encloses the through-opening (7) through which the fastening piece (5) passes, - the pot base (10) comprises a sealing device (17) enclosing the through-opening (7) and supported on the fastening piece (5) for sealing the raw side (14) against the clean side (15), - the bypass device (16) is part of the sealing device (17). [2] Filter device according to claim 1, characterized bythat the bypass device (16) is designed as a bypass valve which is adjustable depending on at least one parameter between an open state in which the fluid connection between the raw side (14) and the clean side (15) is provided, and a closed state in which this fluid connection is canceled. [3] Filter device according to claim 1 or 2, characterized by that the at least one parameter is a pressure difference between the raw side (14) and the clean side (15) of the fuel or lubricant flowing through the water separator (6) or the temperature of the fuel or lubricant flowing through the water separator (6). [4] Filter device according to one of the preceding claims, characterized by that the sealing device (17) is designed as a sealing lip (18), preferably made of an elastic material. [5] Filter device according to claim 4, characterized bythat the sealing lip (18) is curved in a longitudinal section of the filter device (1) along the axial direction (A) of the filter housing (2) towards the ring filter insert (3). [6] Filter device according to one of the preceding claims, characterized by that the sealing device (17), preferably the sealing lip (18), is pre-tensioned against the fastening socket (5). [7] Filter device according to one of the preceding claims, characterized bythat the sealing device (17), preferably the sealing lip (18), is designed such that when a predetermined threshold differential pressure of the fuel or lubricant flowing through the water separator (6) between the raw side (14) and the clean side (15) is exceeded, it is moved away from the fastening nozzle (5) so that a direct fluid connection between the raw side (14) and the clean side (15) is established through the resulting space between the sealing device (17) and the fastening nozzle (5). [8] Filter device according to one of the preceding claims, characterized by that the bypass device (16) comprises at least one recess (19) formed in the sealing device (17), preferably in the sealing lip (18), by means of which a direct fluid connection between the raw side (14) and the clean side (15) is created by bypassing the membrane (13). [9] Filter device according to claim 8, characterized bythat the recess (19) is designed as a through gap (20) or as a through slot. [10] Filter device according to claim 8 or 9, characterized by that the recess (19), in particular the through-gap (20) or through-slot, extends along the axial direction (A) in the radial direction (R) of the water separator (6) with respect to a plan view of the annular pot base. [11] Filter device according to one of claims 7 to 9, characterized by that the bypass device (16) comprises at least two recesses (19), preferably a plurality of recesses (19), which are arranged along a circumferential direction (U) of the sealing device (18), preferably of the sealing lip (19), at a distance from one another, preferably equidistant from one another. [12] Filter device according to one of claims 7 to 11, characterized bythat the recess (19) is adjustable between an open state, in which it provides the fluid connection between the raw side (14) and the clean side (15), and a closed state, in which this fluid connection is canceled. [13] Filter device according to claim 12, characterized by in that, in order to realize the adjustability between the open and the closed state, the material of the sealing device (17), preferably of the sealing lip (18), in the region of at least one recess (19) and / or the geometry of at least one recess (19) are selected such that the recess (19) can be closed by thermal expansion of the material. [14] Filter device according to one of the preceding claims, characterized by that the material of the sealing device (17) is or comprises an elastomer. [15] Filter device according to one of the preceding claims, characterized bythat the pot base (11) and the sealing device (17), preferably the sealing lip (18), are made of the same material. [16] Filter device according to one of the preceding claims, characterized by that the sealing device (17), preferably the sealing lip (18), is formed integrally on the pot base. [17] Filter device according to one of claims 9 to 16, characterized by that the through gap (20) or through slot has a gap or slot width of at most 1 mm, preferably of at most 0.7 mm. [18] Filter device according to one of the preceding claims, characterized by that in a peripheral wall of the fastening nozzle (5) at least one through-opening, preferably a plurality of through-openings, is arranged, via which water separated in the raw side (14) can be collected and / or discharged. [19] Water separator (6) for a filter device (1), in particular according to one of the preceding claims, - with a hydrophobic membrane (13) which is permeable to fuels and lubricants and separates a raw side (14) of the water separator (6) from a clean side (15), - with a bypass device (16) which provides a fluid connection between the raw side (14) and the clean side (15) bypassing the membrane (13), - wherein the water separator (6) is pot-shaped and comprises an annular pot base (10) which encloses a through opening (7).

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