DE102013211209B4 - Filter insert for a liquid filter, in particular for a fuel filter - Google Patents

Abstract

Filter insert for a liquid filter, in particular for a fuel filter, wherein the filter insert (100) has a filter element (140) for separating dirt particles and / or water, wherein the filter insert (100) extends along a longitudinal axis (150), characterized in that at least one electrical conductor (200) suitable for detecting water is non-detachably connected to the filter cartridge (100).

Description

State of the art

The invention relates to a filter insert for a liquid filter, in particular for a fuel filter, with the features of the preamble of the independent device claim and the use of the filter insert according to the invention in a liquid filter.

In many fields of technology, filtration of liquids, for example, with a liquid filter is necessary to allow safe operation of the downstream components of the liquid filter. For example, fuel filters are used in the fuel supply system of internal combustion engines for the separation of particles in the fuel and water. The fuel supply system usually consists of a tank, at least one fuel line, at least one fuel pump, a fuel filter and an injection system. Such liquid filters or fuel filters used in fuel supply systems usually have a filter housing and a filter insert located therein, the filter insert serving to separate particles and water.

Water separated from the fuel is often collected in a lower portion of the fuel filter viewed in the direction of gravity. In order to ensure a reliable filtering effect and to prevent that already separated water returns to the purified fuel or affects the deposition of particles and / or water on the dirty side of the filter cartridge, in the housing of the fuel filter, a sensor is often arranged, the level of the Detects already separated water and makes it possible to detect when the water level in the liquid filter exceeds a certain level.

From the DE 10 2011 081 141 A1 For example, a filter device with a filter housing and a filter insert arranged therein for filtering out foreign substances and water from a medium flowing through the filter housing is known. The filter device has a dehydrator for discharging the filtered out water from the filter device, wherein the dehydrator is coupled by means of a latching connection to the filter housing.

From the DE 20 2009 000 429 U1 a fuel filter with a filter housing, a filter element and a water collection chamber is known.

From the DE 100 29 539 A1 is a filter with a filter cartridge known through which a water level sensor can be plugged.

From the DE 10 2009 032 036 For example, a fuel filter having a hollow body therein is known, wherein a water sensor unit is disposed on the hollow body.

From the US 5,213,682 a fuel supply system is known in which a sensor unit is releasably connectable to a filter cap head.

Disclosure of the invention

Advantages of the invention

According to the invention, a filter insert for a liquid filter, in particular for a fuel filter, is proposed, wherein the filter insert has a filter element for separating dirt particles and / or water, wherein the filter insert extends along a longitudinal axis. According to the invention, at least one electrical conductor which is suitable for detecting water is connected to the filter insert, in particular inseparably connected to the filter insert.

Compared to the prior art, the filter insert according to the invention for a liquid filter has the advantage that the suitable for detecting water electrical conductor, which serves as a kind of water sensor, each time the filter insert, for example for maintenance, new and unused and thus no change Age-related malfunction has. This always ensures a safe and reliable operation of the detection of a critical level of collected water in the liquid filter.

Such a filter insert according to the invention is particularly advantageously used in a liquid filter, in particular in a fuel filter.

Advantageous embodiments and further developments of the invention are made possible by the measures specified in the dependent claims.

In an advantageous embodiment of the filter insert, the filter element is set in an extension direction parallel to the longitudinal axis, ie in the axial extension direction, at its end faces between a first end cap and a second end cap, wherein the at least one electrical conductor a first conductor end and a second end facing away from the first conductor end Conductor end, wherein the first conductor end in the extension direction parallel to the longitudinal axis via a side remote from the filter element first side of the first end cap protrudes, wherein the second conductor end has an electrical connection to the second end cap. This design has the advantageous effect that, when the filter element is installed in a liquid filter, the first end of the conductor is preferably suitable for detecting water in a water collection container arranged below in the normal installation position, ie in the direction of gravity, whereby a water level is already detected can, who has not yet reached the height of the first end cap in normal installation position. The at least one electrical conductor can advantageously be connected electrically by the second conductor end.

A development of the invention provides that the at least one electrical conductor of the filter insert with at least one further electrical conductor, which is connected to the filter cartridge, in particular insoluble, interacts such that when connecting the at least one electrical conductor to the at least one further electrical conductor by means of the water to be detected between the at least one electrical conductor and the at least one further electrical conductor, an electrical parameter, in particular the electrical resistance, is detectably changed. This advantageously has the effect that the at least one electrical conductor and the at least one further electrical conductor together form a water sensor which is arranged or fixed on the filter insert and can be exchanged together with the filter insert. As a result, a particularly cost-effective and easy to change and thus particularly easy to maintain water sensor is created. By varying the length of the at least one electrical conductor and the at least one further electrical conductor, in particular a respective first conductor end of the at least one electrical conductor or the at least one further electrical conductor, the height of the critical level to be detected or critical water level of the collected water are adjusted, in which changes by an electrical connection, in the manner of a short circuit, the at least one electrical conductor with the at least one further electrical conductor detectable by means of the water to be detected, the electrical parameter. For example, upon reaching the critical level, the electrical resistance, the capacitance or the impedance between the at least one electrical conductor and the at least one further electrical conductor is measurably changed. In a preferred embodiment, the at least one electrical conductor and the at least one further electrical conductor are at least partially not surrounded by an electrically insulating sheath.

In another embodiment of the invention, it is provided that the at least one electrical conductor in the mounted in a liquid filter state of the filter insert interacts with at least one further arranged in the liquid filter electrical conductor such that when connecting the at least one electrical conductor to the at least one further electrical Conductor by means of the water to be detected between the at least one electrical conductor and the at least one further electrical conductor, an electrical parameter, in particular the electrical resistance, is detectably changed. This embodiment advantageously has the effect that only the at least one electrical conductor is provided on the filter insert, while the at least one further electrical conductor interacting therewith is arranged in the liquid filter. As a result, the filter insert can be produced particularly inexpensively, and a particularly reliable and reliable detection of water can also be effected in the tilted state of the liquid filter by means of a special design of the at least one further electrical conductor. For example, a plurality of further electrical conductors may be provided in the liquid filter, which are arranged, for example, in a circle around the at least one electrical conductor.

Characterized in that the filter insert is formed as a hollow cylinder with a centrally located recess, wherein the recess extends in the direction of the longitudinal axis, wherein the recess has an inner wall, wherein the at least one electrical conductor is arranged on or in the inner wall of the recess, is advantageously effected in that the at least one electrical conductor is particularly space-saving and against mechanical damage, for. B. during transport or installation, secured in the filter insert is arranged. If the at least one electrical conductor is injected, for example, into the inner wall of the recess, then the at least one electrical conductor is particularly advantageously electrically insulated in a region which preferably comes into contact only with fuel. This electrical insulation advantageously reduces the risk of false electrical signals, which erroneously indicate the presence of water in the area to be monitored.

A further development of the invention provides that the first side of the first end cap has a support element, wherein the support element is suitable for axially supporting the filter insert in the state of the filter insert mounted in a liquid filter, wherein the at least one conductor is arranged on the support element. This refinement advantageously ensures that the at least one conductor is mechanically stabilized by the arrangement on the support element, thereby ensuring the detection of the water permanently and reliably. A kinking or bending of the At least one electrical conductor during assembly of the filter cartridge in the liquid filter or during operation is thereby reliably prevented. The support element is, for example, a rigid support element or a spring-like support element, for example in the form of a leaf spring or a spiral spring.

In a further development of the invention, the filter insert is used in a fluid filter, in particular in a fuel filter, wherein the filter body comprises the following components: a housing cover and a housing cup, wherein the housing cup with the housing cover is tightly closed, for example by Screwing or caulking. Furthermore, the filter housing comprises at least one liquid inlet and at least one liquid outlet, wherein the at least one liquid inlet and the at least one liquid outlet are arranged on the housing cover and can be flowed through by liquid. The housing cup also has a water collecting space. The filter insert is detachably arranged in the housing cup such that the first conductor end of the at least one electrical conductor protrudes into the water collecting space and that the electrical connection of the second conductor end of the at least one electrical conductor is electrically connected to an electrical connection element on the filter housing. This advantageously has the effect that the signals produced and detected during the detection of water are conducted electrically in the at least one electrical conductor into the electrical connection element of the filter housing and from there forwarding to, for example, a control device arranged outside the liquid filter becomes possible. In this way, a reliable and secure electrical contact of acting as a water sensor at least one electrical conductor is always guaranteed. Particularly advantageous can be determined either mechanically or electrically by means of the electrical connection element, whether a filter cartridge is mounted in the fluid filter. For example, the electrical resistance in the connection element of the filter housing changes as soon as the second conductor end of the at least one electrical conductor is electrically connected to the electrical connection element of the filter housing, whereby the presence of the filter element is indicated. Or the second conductor end of the at least one electrical conductor causes correct installation, for example by the correct electrical contact closure with the electrical connection element of the filter insert, a mechanical change, for example by moving a bolt that fold away a spring, or similar mechanisms, which, for example, only the housing cover is fixed to the housing cup. In this way, it is particularly advantageously prevented that the liquid filter is operated without a filter cartridge and components of the fuel supply system located downstream of the fluid filter are damaged by unfiltered fuel.

Characterized in that with the electrical connection element of the filter housing an evaluation circuit is connected, which is suitable for the evaluation of electrical signals of the at least one electrical conductor, wherein the evaluation circuit is adapted to provide a device outside of the liquid filter further electrical signals, which on the presence of Provide information at least one electrical conductor and whether the water level in the water collection chamber exceeds a certain level is advantageously effected that already in the liquid filter preprocessing of the signals of at least one electrical conductor is performed and, for example, processed digital signals or processed or unprocessed analog electrical signals be sent to a located outside of the liquid filter control unit. In this way, a signal can be sent to the control unit in a particularly advantageous manner, wherein the signal gives an indication as to whether a filter insert is ever mounted in the liquid filter. In the absence of a filter cartridge, the controller may then turn on a warning lamp in a display device that indicates a fault in the fluid filter.

Characterized in that the at least one further conductor is arranged on the housing cup of the liquid filter, wherein an end portion of the further electrical conductor protrudes into the interior of the housing cup, is advantageously effected that the water sensor formed from the at least one electrical conductor and the at least one further conductor particularly robust can be designed, since the at least one further electrical conductor can be designed in a particularly stable form.

A development of the invention provides that the housing cup is at least partially made of an electrically conductive material and that the housing cup forms the at least one further conductor. This advantageously has the effect that the detection of water by means of a changing electrical parameter, in particular the resistance, the capacitance or the impedance, between the at least one electrical conductor and the at least one further electrical conductor is made possible in a particularly simple, robust and reliable manner , For example, the bottom of the housing cup and / or an adjoining region of the wall of the housing cup is formed in particular from an electrically conductive material, for example made of metal or of an electrically conductive plastic. Preferably, the thus electrically conductive region of the housing cup is electrically connected to the electrical connection element of the filter housing.

The fact that the at least one electrical conductor and the end region of the at least one further electrical conductor in the normal installation position of the liquid filter at least partially overlap in their projection on the longitudinal axis, is advantageously effected that the detection of water ensures particularly reliable and even in example tilted position the liquid filter is ensured.

A development of the invention provides that the end region of the at least one further electrical conductor surrounds a surface at its end facing the filter element, and in particular is designed as an annular structure, wherein the at least one electrical conductor in the direction of the longitudinal axis within the border through the protrudes from the end region of the at least one further electrical conductor framed surface. This advantageously has the effect that water located in the water collecting space of the housing cup, which exceeds a certain level, can be reliably detected even in the tilted position of the liquid filter. By, for example, a ring-shaped closed design of the end region, the achievement of a critical level of the collected water can reliably be reliably determined in any tilting direction of the liquid filter.

Characterized in that a further support member is arranged in the housing cup, wherein the further support member for axial support of the filter insert is suitable, wherein the end portion of the at least one further conductor is arranged on the further support member is advantageously effected that the filter insert always safe in the axial direction in Liquid filter is set and that the at least one further conductor is reliably mechanically stabilized and protected from damage during operation or during installation of the filter cartridge.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

Brief description of the drawings In the drawings:

1a a cross section of a first embodiment of a filter insert according to the invention;

1b a cross section of a second embodiment of a filter insert according to the invention;

2 a cross-section of a liquid filter in a first embodiment with a filter insert according to the invention according to the embodiment of 1a ;

3a a cross section of a liquid filter in a first embodiment of a second embodiment with a filter insert according to the invention according to the embodiment of 1b ;

3b a section of a cross section of a liquid filter in a second embodiment of a second embodiment with a filter insert according to the invention according to the embodiment of 1b ;

3c a cross section of the liquid filter according to the embodiment of 3b in a tilted state.

Embodiments of the invention

In the reference numerals used in the drawings, elements having the same function have the same reference number.

In 1a is a filter cartridge 100 for a liquid filter, preferably for a fuel filter. The filter insert 100 includes a filter element 140 , which is suitable for separating particles and / or water from the liquid and extends in the direction of a longitudinal axis 150 , The filter element 140 has a recess in its interior 142 , In the illustrated embodiment, a centrally located recess 130 , with an inner wall 132 on. The filter element 140 consists for example of a hydrophilic or of a hydrophobic material and has for filtration of particles a pore size of for example between 10 microns (microns) and 60 microns, preferably between 20 microns and 50 microns. It is folded star-shaped in an exemplary embodiment. However, other embodiments are conceivable, for example, a filter element 140 which is in the direction of the longitudinal axis 150 is flowed through. Also conceivable is a two-part filter element 140 , which is a two-part filter cartridge 100 designed, wherein a first part of the filter element 140 Has coalescing properties and, for example, is arranged radially outward and a second part of the filter element 140 has hydrophobic properties for water separation. In such an embodiment, water droplets in the fuel become larger as they pass through the coalescing, for example, hydrophilic material Droplets formed, which can then be deposited on the second filter element part.

The filter insert 100 indicates at a first end 102 a first end cap 110 and at a second end 104 a second end cap 120 on, being in the second end cap 120 for example, centrally a passage opening 128 is arranged. The filter element 140 is between the first end cap 110 and the second end cap 120 arranged and connected with its two end faces fluid-tight with these.

The second end cap 120 indicates at its the filter element 140 side facing away from the passage opening 128 limiting neck 122 on. The stub 122 protrudes in the illustrated embodiment on the substantially flat-shaped plane of the second end cap 120 out. At its end facing away from the filter insert the nozzle can be 122 connect to a filter housing a liquid filter or even attach, for example by means of a thread arranged at this end 124 , To the neck 122 around is a sealing element 126 , For example, a commercial O-ring, arranged during assembly of the filter cartridge 100 , z. B. on a housing cover 520 a liquid filter 400 , the filter element 100 waterproof seals.

At the filter insert 100 is at least one electrical conductor 200 arranged as well as at least one further electrical conductor 250 , In the illustrated embodiment, a first conductor end protrudes 210 of the at least one electrical conductor 200 via a first one of the filter element 140 opposite side 112 the substantially flat first end cap 110 out. In the same way protrudes a first conductor end 260 the at least one further electrical conductor 250 on the first page 112 the first end cap 110 out. The first conductor end 210 of the at least one electrical conductor 200 is from the first conductor end 260 the at least one further electrical conductor 250 in a direction perpendicular to the longitudinal axis 150 spaced. The at least one electrical conductor 200 and the at least one further electrical conductor 250 preferably run on the inner wall 132 the recess 142 or embedded in the inner wall 132 the recess 142 of the filter element 140 in the axial direction, ie in the direction of the longitudinal axis 150 , to the second end cap 120 , Such an embedding can be achieved, for example, by overmolding the at least one electrical conductor 200 and / or the at least one further electrical conductor 250 with the inner wall preferably formed of an electrically insulating plastic 132 the recess 142 will be realized.

The at least one electrical conductor 200 and the at least one further electrical conductor 250 preferably run on or in the second end cap 120 radially outward and form on the radially outer side of the second end cap 120 an electrical connection 290 , The electrical connection 290 is thereby from a second conductor end 220 of the at least one electrical conductor 200 and from a second conductor end 270 the at least one further electrical conductor 250 educated. In the illustrated embodiment, the electrical connection 290 formed by that the second conductor end 220 of the electrical conductor 200 in the axial direction below the second end 270 the at least one further electrical conductor 52 is arranged. The two second conductor ends can do just as well 220 . 270 may also be arranged vice versa or radially projecting, for example viewed in the radial direction at opposite ends of the second end cap.

1b illustrates a second embodiment of the filter cartridge according to the invention. In this embodiment, only the at least one electrical conductor 200 intended. The electrical connection 290 is in the nozzle in this embodiment 122 realized in that the second conductor end 270 of the at least one electrical conductor 200 from the inside of the neck 122 through the neck 122 passed through on the outside thereof. At the first page 112 the first end cap 110 is a support element in the illustrated embodiment 160 arranged, with which the filter cartridge can be supported in the assembled state in the axial direction. The support element 160 is executed in, for example, in a hollow cylindrical manner, wherein the support element 160 in the wall of its hollow cylindrical shape breakthroughs 162 such that an inlet of liquid, for example water, into the interior of the hollow cylindrical shape of the support element 160 is possible. The first conductor end 210 of the at least one electrical conductor 200 preferably projects into the interior of the hollow cylindrical shape of the support element 160 into it. This is the first conductor end 210 of the at least one electrical conductor 200 protected particularly advantageous against damage during transport or during assembly. The support element 160 is in the illustrated embodiment substantially centrally on the first end cap 110 arranged. But it is equally possible that more than one support element 160 at the first end cap 110 is provided or that the one support element 160 at a non-centric location of the first end cap 110 is arranged.

2 shows a liquid filter 400 , For example, for the filtration of fuels, in which a filter insert according to the invention 100 according to the embodiment 1b is mounted. The liquid filter 400 has a filter housing 500 on, wherein the filter housing a housing cover 520 and a housing cup 510 includes, wherein the housing cup 510 with the housing cover 520 tight, in particular fluid-tight, can be closed. The housing cover 520 For this purpose, for example, with the interposition of another sealing element 530 on the housing cup 510 screwed or to the housing cup 510 crimped. The liquid filter is preferred 400 mounted so that the housing cup bottom 512 along the direction of gravity (g) arrow pointing 900 , that is, pointing downward in the figure, shows.

The case mug 510 has a housing cup bottom 512 and a housing cup inner wall 514 on that together with the housing cover 520 the interior of the liquid filter 400 circumscribe.

The housing cover 520 has at least one fluid inlet 522 and at least one liquid drain 524 on. Through the liquid feed 522 flows unfiltered liquid, in particular fuel, along the arrows in the liquid filter 400 into it, while the filtered liquid the liquid filter 400 over the liquid drain 524 leaves in the direction of the arrow.

The case mug 510 and the housing cover 520 are made of a plastic material, for example of polyamide. However, other materials are conceivable, such as metals.

In the housing mug 510 is the filter insert according to the invention 100 detachably arranged and separates one on the outside of the filter cartridge 100 lying dirt side 410 from one inside the filter cartridge 100 lying clean side 420 , The filter insert 100 is for example by means of his neck 122 on the housing cover 520 set fluid-tight. The filter insert 100 This is done, for example, at its neck 122 in the housing cover 520 screwed fluid tight. The sealing of the filter insert 100 against the housing cover 520 is by means of the sealing element 126 accomplished, which between the neck 122 and one on the housing cover 520 arranged, circumferential sealing bar 526 is fixed.

The case mug 510 also has a water collection room 600 on, in the picture at the bottom of the liquid filter 400 is arranged and in which the deposited on the filter cartridge water 610 collects. Since the water has a higher specific gravity than the fuel to be filtered, the filter insert drops 100 water separated from the fuel in the form of drops of water 612 in the liquid filter 400 downward. In the housing cup bottom 512 There is also a water drain 620 with a water drain plug 622 , By opening the drain plug 622 can that in the water collection room 600 collected water 610 over the water drain 620 from the case cup 510 be removed.

The collected water 610 has a water level (L) at rest, for example, a non-critical water level (L1). As long as the level of the collected water 610 does not exceed a critical for the filtration of the fuel level (L2), the operation of the liquid filter is safe. Exceeds the level of collected water 610 the critical level (L2), so the water must by means of the water drain 620 be drained.

The achievement of the critical water level (L2) should be indicated by a water sensor. According to the invention in the illustrated embodiment, the water sensor by a filter insert 100 arranged electrical conductors 200 and one also on the filter cartridge 100 arranged further electrical conductors 250 educated. The first conductor end 210 of the electrical conductor 200 and the first conductor end 260 the further electrical conductor 250 protrude on the first page 112 the first end cap 110 down, the water collection room 600 of the housing cup 510 referring, from the filter cartridge 100 from. The first two conductor ends 210 . 260 are formed, for example, from non-insulated metallic material. As long as the critical level (L2) is not reached, for example at the uncritical level L1, that between the electrical conductor 200 and the other electrical conductor 250 measurable electrical resistance by the distance between the electrical conductor 200 and the other electrical conductor 250 , the length of the first conductor ends 210 . 260 and the electrical resistivity of the intermediate fuel. Since fuel has a different resistivity than water, it changes between the electrical conductor 200 and the other electrical conductor 250 detectable electrical resistance as soon as the collected water 610 reached the critical level (L2). In this case, the first conductor end 210 of the electrical conductor 200 with the first conductor end 260 the further electrical conductor 250 by means of the collected water 610 connected, resulting in the between the two conductors 200 . 250 measurable electrical resistance to an uncritical level (eg L1) of the collected water 610 changes. Analogously, capacitance or impedance differences that occur as soon as the collected water can be detected and determined 610 instead of fuel between the first conductor end 210 of the electrical conductor 200 and the first conductor end 260 the further electrical conductor 250 to come to rest.

In the illustrated embodiment of the liquid filter 400 is at the upper edge of the housing cup viewed from the figure 510 a connection element 550 arranged, which in turn to an evaluation circuit 560 is fixed. The evaluation circuit 560 and the connection element 550 are on the housing inner wall 514 arranged.

In an alternative, not shown, embodiment, the evaluation circuit 560 on the outside of the housing cup 510 , So on the outer wall, arranged. In this case, the connection element 550 from the inside of the filter housing 500 through the wall of the housing cup 510 , preferably fluid-tight, on the outside of the housing cup 510 passed there and is there electrically with the evaluation circuit 560 contacted.

The on the side of the second end cap 120 outstanding electrical connections 290 of the electrical conductor 200 and the further electrical conductor 250 are electrically connected to the connection element 550 connected. About the connection element 550 For example, an electrical voltage between the electrical conductors 200 and the other electrical conductor 250 be applied and so the electrical resistance or other electrical variable, such as the capacitance or an impedance, between the electrical conductor 200 and the other electrical conductor 52 be recorded. Is not a filter at all 100 mounted or is the filter cartridge 100 incorrectly mounted, there is no electrical and mechanical contact between the electrical connection 290 and the connection element 550 and a value of the electrical parameter is detected that indicates the absence of the filter cartridge 100 or incorrect mounting of the filter cartridge 100 displayed.

The evaluation circuit 560 has two contacting elements in the illustrated embodiment 570 on which the wall of the housing cup 510 pass through fluid-tight and on the outside of the housing cup with a plug contact 700 can be contacted. By means of an electrical line 702 can on the contact element 570 tapped electrical signals to an outside of the liquid filter 400 be forwarded control unit. In an embodiment not shown here, the connecting element 550 without the interposition of an evaluation circuit 560 fluid-tight with the contacting elements 570 electrically connected. In the evaluation circuit 560 For example, electrical or electronic components include user-specific integrated circuits (ASIC) that are suitable for connection via the connection elements 550 to process, evaluate and / or amplify detected electrical signals. For example, a on the connection element 550 applied electrical (analog) signal just be amplified, so that at Kontaktierelement 570 an amplified analog electrical signal 802 is applied. The evaluation circuit 560 can on the connection element 550 however, also process detected electrical signals in such a way that at the contacting element 570 a digital signal 800 is provided, which is suitable, one with the plug contact 700 connected control unit to inform about various operating conditions of the liquid filter. For example, the evaluation circuit may provide a signal indicating the presence or absence of the filter cartridge 100 signaled, also an information can be provided, the achievement of a certain water level, z. B. the critical level (L2) of the collected water 610 , indicates.

In 3a is a second embodiment of the liquid filter 400 shown in which a filter cartridge 100 according to the embodiment 1b is mounted. In contrast to the housing cup 510 of the liquid filter 400 out 2 is in the illustrated embodiment on the housing cup bottom 512 a hollow cylindrical further support element 580 with breakthroughs 582 arranged. The support element is suitable, the filter cartridge 100 in the direction of the longitudinal axis 150 support and between the housing cup bottom 512 and the housing cover 520 clamp. The breakthroughs 582 in the further support element 580 allow the entry of liquid, especially collected water 610 , in the interior of the hollow cylindrical further support member 580 , In the figure, viewed from above, the first conductor end protrudes 210 of the at least one electrical conductor 200 , which is arranged on the filter insert, in the hollow cylindrical further support element 580 into it. From the housing mug ground 512 protrudes the first conductor end 260 the further electrical conductor 250 in the form of an end region 280 for example, vertically upwards into the interior of the housing cup. The end region is preferred 280 the further electrical conductor 250 firmly with the other support element 580 mechanically connected and is thereby mechanically stabilized.

In the normal operating state, ie in the state in which the longitudinal axis 150 essentially parallel to the direction of gravity along the arrow 900 is aligned, overlap in a projection on the longitudinal axis 150 the end area 280 the further electrical conductor 250 and the first conductor end 210 of the electrical conductor 200 in an overlap area 286 , This makes it particularly reliable to reach the critical level (L2) of the collected water 610 in the water collection room 600 detectable, for example, in a slightly tilted state of the liquid filter 400 ,

The further electrical conductor 250 is also electrical with the evaluation circuit 560 connected. For example, the other electrical conductor 250 in the wall of the housing cup 510 injected.

In 3b is a section of the case mug 510 a further embodiment of the embodiment of the liquid filter 400 out 3a shown. Here is the end area 280 the further electrical conductor 250 with an annular structure 282 configured having a surface in a direction substantially to the extension direction of the longitudinal axis 150 limited vertical plane. Preferably, the center of the surface of the example circular annular structure is located 282 approximately on the longitudinal axis 150 of the liquid filter 400 , In other embodiments of the invention, the annular structure 282 also have a shape other than a circular shape, for example a triangular, an elliptical, a square or another shape. The ring shaped like a wire loop 282 is viewed in the figure from above from the first conductor end 210 of the electrical conductor 200 pierced in such a way, preferably in the middle, that in the untilted state of the liquid filter 400 along the longitudinal axis 150 considers at least a part of the first conductor end 210 of the electrical conductor 200 below that of the annular structure 282 enclosed or bounded surface lies. By means of this construction is a particularly reliable detection of the critical level (L2) of the collected water 610 also in the tilted state of the liquid filter 400 possible.

In 3c is the mode of action of the ring-shaped structure 282 trained end area 280 the further electrical conductor 250 shown. In the tilted state of the liquid filter 400 when exceeding the critical level (L2) of the collected water 610 an electrical connection between the further electrical conductor 250 and the electrical conductor 250 by means of the collected water 610 manufactured, because regardless of the tilting direction of the liquid filter 400 that of the annular structure 282 the further electrical conductor 250 limited edge of the area the level of the level of the collected water 610 cuts. In this way, the electrical conductor 200 electrically with the further electrical conductor 250 by means of the collected water 610 connected in the manner of a short circuit. By the area bounded by the end so that of the electrical conductor reacts 200 and the other electrical conductor 250 trained water sensor more sensitive and reliable on reaching a critical level (L2) than when the other electrical conductor 250 only in the form of a single upwardly projecting first conductor end 260 is trained.

Equivalently, the annular structure 282 also at the first end of the ladder 210 of the electrical conductor 200 be educated. Moreover, it is possible that instead of an annular structure 282 , which from the end area 280 the further electrical conductor is formed, several inside the housing cup 510 from the housing cup bottom 512 protruding first conductor ends 260 the further electrical conductor 250 in different places of the housing cup bottom 512 are arranged. The several are inside the housing cup 510 protruding first ends 260 the further electrical conductor 250 either all together with the same additional electrical conductor 250 connected or there are several more electrical conductors 250 available. In such an embodiment, at least two are preferred by 180 ° in the angular range with respect to the longitudinal axis 150 staggered first conductor ends 260 the further electrical conductor 250 provided, preferably three, most preferably four first conductor ends 260 the further electrical conductor 250 , for example, at a uniform angular distance about the longitudinal axis 150 around from the housing mug ground 512 inside the housing cup 510 protrude.

Such filter cartridges can be used for example in liquid filters for gasoline and diesel-powered vehicles or in DENOX filters for the filtration of urea solution for the exhaust gas aftertreatment of motor vehicles. The use in oil filters or in filters for filtering hydraulic oil, for example in wind turbines or gear oil is conceivable.

Claims (14)

Filter insert for a fluid filter, in particular for a fuel filter, wherein the filter cartridge ( 100 ) a filter element ( 140 ) for separating dirt particles and / or water, wherein the filter cartridge ( 100 ) along a longitudinal axis ( 150 ), characterized in that at least one electrical conductor ( 200 ), which is suitable for detecting water, insoluble with the filter cartridge ( 100 ) connected is. Filter insert according to claim 1, characterized in that the filter element ( 140 ) in a direction to the longitudinal axis ( 150 ) parallel extension direction at its end faces between a first end cap ( 110 ) and a second end cap ( 120 ), wherein the at least one electrical conductor ( 200 ) a first conductor end ( 210 ) and one from the first conductor end ( 210 ) remote second Leader ( 220 ), wherein the first conductor end ( 210 ) in the direction of extension parallel to the longitudinal axis ( 150 ) via one of the filter element ( 140 ) facing away from the first page ( 112 ) of the first end cap ( 110 protrudes), wherein the second conductor end ( 220 ) on the second end cap ( 120 ) an electrical connection ( 290 ) having. Filter insert according to claim 1, characterized in that the at least one electrical conductor ( 200 ) of the filter insert ( 100 ) with at least one further electrical conductor ( 250 ), which with the filter cartridge ( 100 ), in particular insoluble, is so interacted, that in the connection of the at least one electrical conductor ( 200 ) with the at least one further electrical conductor ( 250 ) by means of the water to be detected between the at least one electrical conductor ( 200 ) and the at least one further electrical conductor ( 250 ) an electrical parameter, in particular the electrical resistance, is detectably changed. Filter insert according to claim 1, characterized in that the at least one electrical conductor ( 200 ) in the liquid filter mounted state of the filter cartridge ( 100 ) with at least one further arranged in the liquid filter electrical conductor ( 250 ) interacts such that in the connection of the at least one electrical conductor ( 200 ) with the at least one further electrical conductor ( 250 ) by means of the water to be detected between the at least one electrical conductor ( 200 ) and the at least one further electrical conductor ( 250 ) an electrical parameter, in particular the electrical resistance, is detectably changed. Filter insert according to one of claims 1 to 4, characterized in that the filter insert ( 100 ) hollow cylindrical with a centrally located recess ( 130 ) is formed, wherein the recess ( 130 ) in the direction of the longitudinal axis ( 150 ), wherein the recess ( 130 ) an inner wall ( 132 ), wherein the at least one electrical conductor ( 200 ) on or in the inner wall ( 132 ) of the recess ( 132 ) is arranged. Filter insert according to claim 2, characterized in that the first side ( 112 ) of the first end cap ( 110 ) a support element ( 160 ), wherein the support element ( 160 ) in the liquid filter mounted state of the filter cartridge ( 100 ) for axial support of the filter cartridge ( 100 ), wherein the at least one conductor ( 200 ) on the support element ( 160 ) is arranged. Use of a filter cartridge according to one of the preceding claims in a fuel filter. Use according to claim 2 and claim 7, characterized in that the liquid filter ( 400 ) a filter housing ( 500 ), wherein the filter housing ( 500 ) comprises the following components: - a housing cover ( 520 ), - a housing cup ( 510 ), wherein the housing cup ( 510 ) with the housing cover ( 520 ) is tightly closed, - at least one fluid inlet ( 522 ), - and at least one liquid outlet ( 524 ), wherein the at least one liquid feed ( 522 ) and the at least one liquid outlet ( 524 ) on the housing cover ( 520 ) are arranged, wherein the housing cup ( 510 ) a water collection room ( 600 ), wherein the filter cartridge ( 100 ) in the housing cup ( 510 ) is detachably arranged such that the first conductor end ( 210 ) of the at least one electrical conductor ( 200 ) in the water collection room ( 600 ) and that the electrical connection ( 290 ) of the second conductor end ( 220 ) of the at least one electrical conductor ( 200 ) with an electrical connection element ( 550 ) on the filter housing ( 500 ) is electrically connected. Use according to claim 8, characterized in that with the electrical connection element ( 550 ) of the filter housing ( 500 ) an evaluation circuit ( 560 ) connected to the evaluation of electrical signals of the at least one electrical conductor ( 200 ) is suitable, wherein the evaluation circuit ( 560 ) to a device outside the fluid filter ( 400 ) to provide further electrical signals which indicate the presence of the at least one electrical conductor ( 200 ) And whether the water level in the water collection room ( 600 ) exceeds a certain level. Use according to claim 8 and one of claims 3 or 4, characterized in that the at least one further conductor ( 250 ) on the housing cup ( 510 ) of the liquid filter ( 400 ), wherein an end region ( 280 ) of the further electrical conductor into the interior of the housing cup ( 510 ) protrudes. Use according to claim 3 or 4 and claim 8, characterized in that the housing cup ( 250 ) is designed at least partially made of an electrically conductive material and that the housing cup the at least one further conductor ( 250 ). Use according to claim 10, characterized in that the at least one electrical conductor ( 200 ) and the end area ( 280 ) of the at least one further electrical conductor ( 250 ) in normal installation position of the liquid filter ( 400 ) at least partially in their projection onto the longitudinal axis ( 150 ) overlap. Use according to claim 10, characterized in that the end region ( 280 ) of the at least one further electrical conductor ( 250 ) at its the filter cartridge ( 100 ) is bordered by a surface, and in particular as an annular structure ( 282 ), wherein the at least one electrical conductor ( 200 ) in the direction of the longitudinal axis ( 150 ) within the border by the one from the end region ( 280 ) of the at least one further electrical conductor ( 250 ) rimmed surface protrudes. Use according to claim 10, characterized in that in the housing cup ( 510 ) another support element ( 560 ), wherein the further support element ( 560 ) for axial support of the filter cartridge ( 100 ), the end region ( 280 ) of the at least one further conductor ( 250 ) on the further support element ( 560 ) is arranged.

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