Abstract:
A water separator element ( 14 ) for a fuel filter ( 10 ) having two water level electrodes ( 34, 36 ) for detecting backed-up water in a water collection chamber ( 32 ) of the fuel filter ( 10 ). The water level electrodes ( 34, 36 ) can be electrically contacted by means of two contact electrodes ( 40, 42 ), said contact electrodes ( 40, 42 ) being connected in an electrically conductive manner to the water level electrodes ( 34, 36 ). The disclosure further relates to a fuel filter comprising a water separator element of this type.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a water separator element for a fuel filter of a motor vehicle. 
       PRIOR ART 
       [0002]    A water separator element for filtering fuel of a motor vehicle is known from DE 2011 078 362 A1. The known water separator element is embodied in two stages for separating water. It has a particle filter medium and a final separator screen for separating water. The separated water collects in a water collection chamber. A water level sensor whose electrodes are conducted in a supporting rod of the fuel filter detects when the level of the accumulated water in the water collection chamber is too high. 
         [0003]    Moreover, known from DE 10 2011 081 141 A1 is providing a dewatering device on a filter housing in order to be able to drain separated water out of the filter housing. The dewatering device is coupled to the filter housing via a snap-on connector. 
         [0004]    WO 2010/049208 A1 discloses a filter device having a water sensor that in the structural unit is embodied with a heating circuit of the filter device. The water sensor has sensor pins that may be coupled to a socket connector via electrical contacts. 
         [0005]    Known from US 2010/0276352 A1 is providing a filter with electrodes for detecting the water level. The electrodes are elastically prestressed and touch one another when the water separator element is in the uninstalled condition. Installing the water separator element causes the electrodes to separate from one another so that they are electrically insulated from one another and only conduct electrical current if the water level is too high. This means that the electrodes are used both for detecting the water level and for ensuring that the water separator element is correctly installed. 
         [0006]    The reliability of water detection in the water collection chamber drops, however, due to wear and impurities in the fuel filter. 
       SUMMARY 
       [0007]    The underlying object of the invention is therefore to make possible long-lasting reliable water detection in a fuel filter. 
         [0008]    The object according to the invention is thus solved using a water separator element for a fuel filter of a motor vehicle, the water separator element having two water level electrodes for detecting accumulated water in a water collection chamber of the fuel filter and the water level electrodes being electrically contactable by means of two contact electrodes, wherein the contact electrodes may be connected in an electrically conductive manner to the water level electrodes. 
         [0009]    When the water separator element is exchanged, the water level electrodes are replaced due to the arrangement of the water level electrodes on the water separator element. Water detection may therefore be long-lastingly reliable. 
         [0010]    The water separator element advantageously has a particle filter medium that is supported on a center tube. In this case the water separator element is in the form of a filter element. 
         [0011]    The water separator element may have a sedimentation opening for water separation. The sedimentation opening is preferably embodied on an end disk of the water separator element. The sedimentation opening is particularly preferably embodied in the form of a sedimentation gap. 
         [0012]    Water separation occurs at particularly high efficiency when the water separator element has a coalescer medium, in particular in the form of a non-woven fabric. 
         [0013]    For separating water, the water separator element may furthermore have a final separator screen, wherein the final separator screen is arranged or embodied in a screen support, the screen support being arranged or embodied radially to the water separator element. The water separating rate is increased significantly using the final separator screen. 
         [0014]    A first contact electrode may be embodied radial to the water separator element longitudinal axis. 
         [0015]    Both contact electrodes are preferably embodied annular radial to the water separator element longitudinal axis. Using the annularly embodied contact electrodes, the screen support may be mounted, rotated about the water separator element in practically any manner, the electrical connection to the water level electrodes being provided in every case. 
         [0016]    The water level electrodes may be embodied in one piece/integrally with the contact electrodes. In this way it is possible to reliably ensure the electrical connection between the water level electrodes and the contact electrodes. 
         [0017]    The contact electrodes may be arranged or embodied, at least in part, on an end plate of the water separator element. Because of this, the contact electrodes may be easily contacted by tapping electrodes arranged on the filter housing. 
         [0018]    At least one connecting line between a water level electrode and a contact electrode may run in the screen support. Alternatively or in addition thereto, a connecting line may run in a center tube. 
         [0019]    A first water level electrode is preferably connected via an electrical connecting line to a first contact electrode that is outwardly disposed relative to the water separator element longitudinal axis, and a second water level electrode is connected to a second contact electrode that is inwardly disposed with respect to the water separator element longitudinal axis, at least part of the connecting line running embedded in the end plate between the second contact electrode and an under side of the end plate. Because of this the water level electrodes may be spaced essentially the same distance from the water separator element longitudinal axis without this resulting in a short circuit between the water level electrodes. Segments of the end plate act as insulators between the second contact electrode and the connecting line. 
         [0020]    The screen support and/or the center tube may be connected via a snap-on connector to the end plate of the water separator element, the water level electrodes each being electrically connected to the contact electrodes via an interruptible resilient contact when the screen support is locked to the end plate. The screen support or the center tube is particularly easy to assemble because of the snap-on connector. 
         [0021]    In another preferred embodiment of the invention, the contact electrodes are arranged or embodied in an interior chamber of the screen support, the contact electrodes each being contactable using a tapping electrode embodied resiliently, at least in part, and the tapping electrodes being arranged or embodied, at least in segments, oriented radially outward on a center tube element of the filter. A particularly easily assembled water separator element is attained using such an arrangement, the electrical connection of the water level electrodes arranged or embodied “below” on the screen support being guided “upward” via the tapping electrodes and beyond via the center tube element. 
         [0022]    It is particularly preferred that the screen support be embodied closed at its under side facing the water level electrodes in the region of the center tube element. The lower part of the inner chamber of the screen support, i.e. the part of the inner chamber of the screen support that can be directed towards the water collection chamber, is preferably embodied closed. Because of this, it is possible to forego a seal between center tube element and screen support, and it is possible especially to forego assembling a sealing ring between center tube element and screen support. 
         [0023]    It is possible to attain a particularly compact and easily assembled structure of the water separator element when the particle filter medium, the coalescer medium, the sedimentation opening, and the final separator screen are arranged successively radial to the water separator element longitudinal axis. 
         [0024]    In another embodiment of the invention, the water separator element may have an electrically conductive shorting bridge for electrically bridging at least two filter housing electrodes arranged or embodied on the interior of the filter housing. Due to the electrically conductive shorting bridge, it may be assured that the water separator element is correctly inserted into the filter housing. Moreover, due to such a shorting bridge it may be assured that only original water separator elements are used in the filter housing, so that damage to the engine due to deficient imitation water separator elements is prevented. 
         [0025]    The invention furthermore relates to a filter having a previously described water separator element and a filter housing that has a water collection chamber, the water level electrodes projecting, at least in part, into the water collection chamber when the water separator element is inserted into the filter housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    Additional features and advantages of the invention result from the following detailed description of a number of exemplary embodiments of the invention, using the figures in the drawings, which illustrate details essential to the invention, and from the claims. 
           [0027]    The features depicted in the drawings are illustrated such that the special qualities of the invention may be rendered visibly clear. Each of the various features may be realized individually by itself or with other features in any combinations for variants of the invention. 
           [0028]      FIG. 1 a    is a sectional perspective elevation of a first water separator element in a highly schematic first filter housing; 
           [0029]      FIG. 1 b    is a partial view of the left side of the first water separator element from  FIG. 1   a;    
           [0030]      FIG. 1 c    is a partial view of the right side of the first water separator element from  FIG. 1   a;    
           [0031]      FIG. 2  is a sectional view of a second water separator element; 
           [0032]      FIG. 3 a    depicts screen support and center tube element of a third water separator element; 
           [0033]      FIG. 3 b    depicts the center tube element from  FIG. 3 a   , without screen support; 
           [0034]      FIG. 3 c    depicts a partial sectional view of the third water separator element from  FIG. 3   a;    
           [0035]      FIG. 4 a    is a perspective elevation of a fourth water separator element; 
           [0036]      FIG. 4 b    is a top view of a second filter housing for receiving the fourth water separator element from  FIG. 4   a;    
           [0037]      FIG. 4 c    is a partial sectional view of the second filter housing according to  FIG. 4 b    with fourth water separator element according to  FIG. 4 a    inserted therein; 
           [0038]      FIG. 5 a    is a perspective elevation of a fifth water separator element; 
           [0039]      FIG. 5 b    is a partial sectional view of the fifth water separator element according to  FIG. 5 a    in a third filter housing; 
           [0040]      FIG. 6 a    is a perspective elevation of a sixth water separator element; 
           [0041]      FIG. 6 b    is a perspective elevation of a fourth filter housing for receiving the sixth water separator element from  FIG. 6   a;    
           [0042]      FIG. 6 c    is a partial sectional view of the fourth filter housing according to  FIG. 6 b    with sixth water separator element according to  FIG. 6 a    inserted therein; 
           [0043]      FIG. 7 a    is a perspective elevation of a seventh water separator element; 
           [0044]      FIG. 7 b    is a perspective elevation of a fifth filter housing for receiving the seventh water separator element from  FIG. 7   a;    
           [0045]      FIG. 7 c    is a partial sectional view of the fifth filter housing according to  FIG. 7 b    with seventh water separator element according to  FIG. 7 a    inserted therein; 
           [0046]      FIG. 8  is a top view of an eighth water separator element; and, 
           [0047]      FIG. 9  is a top view of a ninth water separator element. 
       
    
    
     DETAILED DESCRIPTION 
       [0048]      FIG. 1 a    depicts a first filter  10  in the form of a fuel filter for a motor vehicle (not shown) having a first filter housing  12  that is merely indicated schematically with broken lines. A first water separator element  14  is inserted into the first filter housing  12 . The first water separator element  14  has a particle filter medium  16 , a coalescer medium  18 , a sedimentation opening  20 , and a final separator screen  22 . For reasons of clarity, in  FIG. 1 a    only the end faces of the final separator screen  22  are depicted. A dot-dash arrow  28  indicates the path of the fuel through the particle filter medium  16 , the coalescer medium  18 , the sedimentation opening  20 , and the final separator screen  22 . It may be seen that the particle filter medium  16 , the coalescer medium  18 , the sedimentation opening  20 , and the final separator screen  22  are arranged radial to a water separator element longitudinal axis  30 . The first water separator element  14  is embodied essentially axially symmetrical to the water separator element longitudinal axis  30 . 
         [0049]    Using the coalescer medium  18 , the sedimentation opening  20 , and the final separator screen  22 , the fuel may be effectively freed of water in order to prevent engine damage. The separated water collects in a water collection chamber  32  of the first filter housing  12 . If the water level in the water collection chamber  32  is too high, this is detected by the water level electrodes  34 ,  36 . The water level electrodes  34 ,  36  and the final separator screen are arranged on a screen support  38 . The water level electrodes  34 ,  36  may be electrically contacted via contact electrodes  40 ,  42 . Particularly simple contacting of the contact electrodes  40 ,  42  and simple assembly of the first water separator element  14  is attained using an annular embodiment of the contact electrodes  40 ,  42 : Using the annular embodiment of the contact electrodes  40 ,  42 , the first water separator element  14 , rotated as desired about the water separator element longitudinal axis  30 , may be inserted into the first filter housing  12  , and nevertheless always be correctly contacted. Water detection can always occur reliably because when the water separator element  14  is changed, the water level electrodes  34 ,  36  are also exchanged and thus replaced. 
         [0050]      FIG. 1 b    is a partial view of the first water separator element  14 . It may be seen from  FIG. 1 b    that the radially exterior, first contact electrode  40  is electrically connected to the first water level electrode  34  via an electrical connecting line  44 . The connecting line  44  runs embedded in an end plate  46  of the first water separator element  14 . The first contact electrode  40  and the electrical connecting line  44  are embodied integrally. Moreover, the connecting line  44  and the first water level electrode  34  may be embodied integrally. In the present case, the connecting line  44  and the first water level electrode  34  are electrically connected via a first resilient contact  48 . The screen support  38  may be connected to the end plate  46  of the first water separator element  14  via a snap-on connector  50 . This permits particularly simple assembly of the screen support  38 . When assembling the screen support  38 , an electrically conductive connection between the first water level electrode  34  and the first contact electrode  40  is simultaneously created by the first resilient contact  48 . 
         [0051]      FIG. 1 c    is another partial view of the first water separator element  14 . It may be seen from  FIG. 1 c    that the radially inner, second contact electrode  42  is electrically connected to the second water level electrode  36  via a second resilient contact  52 . When assembling the screen support  38  using the snap-on connector  50 , an electrically conductive connection between the second water level electrode  36  and the second contact electrode  42  is simultaneously created by the second resilient contact  52 . 
         [0052]      FIG. 2  depicts a second water separator element  54 . The second water separator element  54  is identical to the first water separator element  14 . However, water level electrodes  56 ,  58  are not positioned mutually diametrically like the water level electrodes  34 ,  36  (see  FIG. 1 a   ), but instead are spaced apart, at a right angle, about a water separator element longitudinal axis  60 . Moreover, a screen support  62  is embodied integrally with an end plate  64 , the first water level electrode  56  is embodied integrally with a first contact electrode  66 , and the second water level electrode  58  is embodied integrally with a second contact electrode  68 . 
         [0053]      FIG. 3 a    depicts a center tube element  70  of a fuel filter and a screen support  72  of a third water separator element. The center tube element  70  is not a part of a water separator element. The screen support  72  has water level electrodes  74 ,  76 . The water level electrodes  74 ,  76  are each electrically connected to tapping electrodes  78 ,  80 . On its outer circumference, the screen support  72  furthermore has a final separator screen, however for reasons of clarity it is not shown. 
         [0054]      FIG. 3 b    depicts the center tube element.  70 . It may be seen from  FIG. 3 b    that segments of the tapping electrodes  78 ,  80  are embodied resiliently. The tapping electrodes  78 ,  80  produce an electrical connection to the water level electrodes  74 ,  76  (see  FIG. 3 a   ). 
         [0055]    In a partial sectional view of the center tube element  70  and screen support  72  according to  FIG. 3 a   ,  FIG. 3 c    illustrates how this electrical connection is produced. The water level electrodes  74 ,  76  (of which only the first water level electrode  74  is depicted in  FIG. 3 c   ) are each electrically connected to annular contact electrodes  82 ,  84 . The water level electrodes  74 ,  76  (see  FIG. 3 a   ) are embodied integrally with the contact electrodes  82 ,  84 , respectively. The contact electrodes  82 ,  84  are contacted by the tapping electrodes  78 ,  80 , respectively, at least segments of which are resilient, and are each arranged, on the center tube element  70 , with a segment oriented radially outward, and their resiliently embodied segments press against the contact electrodes  82 ,  84 . 
         [0056]    The screen support  72  is embodied closed on the under side  90  facing towards the water level electrodes  74 ,  76  (see  FIG. 3 a   ) in the region of the center tube element  70 . Because of this it is possible to forego a seal, especially a sealing ring, between the center tube element and the screen support. 
         [0057]    In the following, the outer embodiments of additional inventive water separator elements are described that have on their exterior additional electrically conductive shorting bridges for electrically bridging at least two filter housing electrodes arranged or embodied on an interior of the filter housing. 
         [0058]      FIG. 4 a    depicts a fourth water separator element  110 . The fourth water separator element  110  has a particle filter medium  112 . The particle filter medium  112  is embodied as a pleated filter. The particle filter medium  112  is enclosed by a first end plate  114  and a second end plate  116 . 
         [0059]    A first water separator element electrode  120  and a second water separator element electrode  122  are arranged on the outwardly facing surface  118  of the first end plate  114 . The first water separator element electrode  120  is connected to the second water separator element electrode  122  by means of a shorting bridge  124  in the form of an electrical lead. The electrical lead in the present case is embodied in the form of a metal strip. 
         [0060]      FIG. 4 b    illustrates a second filter housing  126  for receiving the fourth water separator element  110  according to  FIG. 4 a   . The second filter housing  126  has a filter housing interior  128 . The filter housing interior  128  faces the fourth water separator element  110  when the fourth water separator element  110  is inserted into the second filter housing  126 . 
         [0061]    A first filter housing electrode  130  and a second filter housing electrode  132  are arranged on the filter housing interior  128 . The first filter housing electrode  130  is embodied radially symmetrical to the longitudinal axis of the second filter housing  126 . In addition, the second housing electrode  132  is embodied radially symmetrical to the longitudinal axis of the second filter housing  126 . The second filter housing electrode  132  is embodied concentric with the first filter housing electrode  130 . In other words, the first filter housing electrode  130  and the second filter housing electrode  132  are embodied essentially in a tire shape or annularly with a common center point. The first filter housing electrode  130  comprises an electrically conductive material, preferably metal. In addition, the second filter housing electrode  132  comprises an electrically conductive material, preferably metal. 
         [0062]      FIG. 4 c    depicts a second filter  134 . The second filter  134  has the second filter housing  126  with fourth water separator element  110  therein, compared to “head down” as illustrated for  FIG. 4 a   . The term “head down” shall be construed as a 180° rotation, the axis of rotation for this rotation running perpendicular to the longitudinal axis of the fourth water separator element  110 . As may be seen from  FIG. 1 c   , segments of the first water separator element electrode  120  and of the second water separator element electrode  122  are embodied curved. The first water separator element electrode  120  and the second water separator element electrode  122  thus have resilient properties. When fourth water separator element  110  is installed in the second filter housing  126 , the first water separator element electrode  120  is in electrical and mechanical contact with the first filter housing electrode  130 . When fourth water separator element  110  is installed in the second filter housing  126 , the second water separator element electrode  122  is in electrical and mechanical contact with the second filter housing electrode  132 . 
         [0063]    A voltage may be applied between the first filter housing electrode  130  and the second filter housing electrode  132 . Then a current flows from the first filter housing electrode  130  to the first water separator element electrode  120 , via the shorting bridge  124  (see  FIG. 1 a   ), to the second water separator element electrode  122  and further to the second filter housing electrode  132 . Depending on the polarity of the applied voltage, the current may also flow in the opposing direction. The current only flows if the fourth water separator element  110  is correctly installed in the second filter housing  126 . Thus, by measuring the current flow, it is possible to discern that the fourth water separator element  110  is correctly installed in the second filter housing  126 . 
         [0064]    The current circuit described in the foregoing may furthermore have a known resistance. By measuring this resistance, it is easy to evaluate whether the fourth water separator element  110  is an original part or an imitation. Moreover, the current circuit described in the foregoing may have a known capacity and/or inductivity. By applying an alternating voltage between the first filter housing electrode  130  and the second filter housing electrode  132 , and by measuring the resultant current, it is possible to precisely evaluate whether the fourth water separator element  110  is an imitation. 
         [0065]    If a control element (not shown) detects that there is an imitation or that the fourth water separator element  110  is not correctly installed in the second filter housing  126 , a visual or acoustic indication thereof may be provided to a user. If the second filter  134  is used in a motor vehicle, the engine management system may be interrupted in order to prevent damage to the motor vehicle. 
         [0066]      FIG. 5 a    depicts a fifth water separator element  136 . The fifth water separator element  136  corresponds to the fourth water separator element  110  according to  FIG. 4 a   . In contrast to the fourth water separator element  110 , the fifth water separator element  136  has a shorting bridge  138  that comprises both the first water separator element electrode and the second water separator element electrode, the water separator element electrodes being connected via an electrical lead. The first water separator element electrode and the second water separator element electrode represent different segments of the shorting bridge  138 . The shorting bridge  138  is connected via an elastic water separator element part  140  to a water separator element body  142  of the fifth water separator element  136 . The shorting bridge  138  is embodied from an electrically conductive material, preferably metal. 
         [0067]      FIG. 5 b    depicts a third filter  144 . The third filter  144  has the fifth water separator element  136 , which, compared to being “head down” in  FIG. 4 a   , is built into a third filter housing  146 . The third filter housing  146  has a first filter housing electrode  148  and a second filter housing electrode  150 . A voltage may be applied between the first filter housing electrode  148  and the second filter housing electrode  150 . When the fifth water separator element  136  is installed in the third filter housing  146 , the filter housing electrodes  148 ,  150  are electrically bridged by the electrically connected water separator element electrodes of the shorting bridge  138 . Because of this, it is possible to check that the fifth water separator element  136  is correctly seated in the third filter housing  146 . Moreover, it is possible to check whether the fifth water separator element  136  is an imitation. 
         [0068]    The filter housing electrodes  148 ,  150  may be embodied radially symmetrical to the longitudinal axis of the third filter housing  146  in order to be able to use the fifth water separator element  136  rotated about its longitudinal axis as desired in the third filter housing  146 . 
         [0069]    The first filter housing electrode  148  and/or the second filter housing electrode  150  may be embodied in the form of an electrically conductive plate, especially a metal plate. 
         [0070]    Alternatively to the third filter housing  146 , the second filter housing  126  according to  FIG. 4 b    may be used in combination with the fifth water separator element  136  according to  FIG. 5   a.    
         [0071]      FIG. 6 a    depicts a sixth water separator element  152 . The sixth water separator element  152  corresponds to the fifth water separator element  136  according to  FIG. 5 a   . In contrast to the fifth water separator element  136 , the sixth water separator element  152  has a shorting bridge  154  in the form of a ring. 
         [0072]      FIG. 6 b    depicts a fourth filter housing  156 . The fourth filter housing  156  has a first filter housing electrode  158  and a second filter housing electrode  160 . 
         [0073]      FIG. 6 c    depicts a fourth filter  162 . The fourth filter  162  has the fourth filter housing  156  according to  FIG. 6 b   . The sixth water separator element  152  (according to  FIG. 6 a   ) of the fourth filter  162  is depicted “head down” in the fourth filter housing  156 . The first filter housing electrode  158  is electrically short circuited with the second filter housing electrode  160  via the shorting bridge  154 . The filter housing electrodes  158 ,  160  are embodied in the form of spring pins. The spring pins have elastic filter housing parts (not shown). A particularly reliable electrical contact is attained using the spring pins. 
         [0074]      FIG. 7 a    depicts a seventh water separator element  164 . The seventh water separator element  164  corresponds to the sixth water separator element  152  according to  FIG. 6 a   . In contrast to the sixth water separator element  152 , the seventh water separator element  164  has a first water separator element electrode ring  166  that annularly surrounds an end plate  168  of the seventh water separator element  164  at its exterior circumference. In different segments, the water separator element electrode ring  166  comprises a first water separator element electrode, a second water separator element electrode, and a direct electrical connection in the form of a shorting bridge between these water separator element electrodes. 
         [0075]      FIG. 7 b    depicts a fifth filter housing  170 . The fifth filter housing  170  has a first filter housing electrode  172  and a second filter housing electrode  174 . 
         [0076]      FIG. 7 c    depicts a fifth filter  176 . The fifth filter  176  comprises the fifth filter housing  170  according to  FIG. 7 b    and the seventh water separator element  164  according to  FIG. 7 a   . The seventh water separator element  164  is depicted “head down” in the fifth filter housing  170 . When installed, the water separator element electrode ring  166  bridges the filter housing electrodes  172 ,  174  (see  FIG. 7 b   ; only the first filter housing electrode  172  is visible in  FIG. 7 c   ). It may be seen from  FIG. 7 c    that the first filter housing electrode  172  is connected to a filter housing body  180  of the fifth filter housing  176  via an elastic filter housing part  178 . The electrical connection between the filter housing electrodes  172 ,  174  and the water separator element electrodes of the water separator element electrode ring  166  is thus even retained after the seventh water separator element  164  has been installed and uninstalled multiple times. The second filter housing electrode (not shown) is also connected to the filter housing body  180  of the fifth filter housing  176  via an elastic filter housing part (not shown). 
         [0077]      FIG. 8  depicts an eighth water separator element  182 . The eighth water separator element  182  has an end plate  184 . A shorting bridge in the form of a contact strip  186  made of metal is embodied on the end plate  184 . The contact strip  186  may be present, for instance, in the form of a metal film. The contact strip  186  has a first water separator element electrode  188  and a second water separator element electrode  190 . The water separator element electrodes  188 ,  190  are directly electrically connected via an ohmic lead  192 . The ohmic lead  192  is embodied in the form of a segment of the contact strip  186 . 
         [0078]      FIG. 9  depicts a ninth water separator element  194 . The ninth water separator element  194  corresponds to the eight water separator element  182 . However, a segment of the contact strip  198 , embodied as an ohmic lead  196 , covered by the plastic of an end plate  200 , is inserted in the end plate  200 . Because of this the ohmic lead  196  is less susceptible to damage. 
         [0079]    In summary, the invention preferably relates to a multistage water separator element. The water separator element preferably has a particle filter medium, a coalescer medium, a sedimentation opening, and a screen support having a final separator screen. Preferably two water level electrodes are arranged on the screen support. The water level electrodes are embodied such that they project into a water collection chamber of a filter housing when the water separator element is installed in the filter housing. Each water level electrode may be contacted via one contact electrode that is preferably essentially annular. The contact electrodes may be contacted using tapping electrodes of a center tube element. In this case, the screen support preferably has, in the water separator element longitudinal direction toward the water level electrodes, a closed receiving shaft for the center tube element so that it is not necessary to provide a seal between center tube element and screen support.