Abstract:
A filter assembly, having a housing including a housing bottom portion; at least one ring filter element that is received by at least one receiving space defined at least in part by the housing, wherein the receiving space includes a receiving space bottom portion; a cover attached to the housing bottom portion and configured for at least partially enclosing the at least one receiving space and the ring filter element, wherein the at least one receiving space may be selectively emptied when the cover is removed; an outlet located at the receiving space bottom portion within the cover; and a closure located on the at least one ring filter element, wherein the closure is configured to at least partially close the outlet when the at least one ring filter element is inserted into the at least one receiving space.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority based on DE 102007009352.9 filed Feb. 23, 2007, which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to a fluid filter, in particular an oil filter for cleaning lubricating oil, in particular for the internal combustion engines of motor vehicles, having the features of the preamble of claim  1 . 
     BACKGROUND 
     EP 1 229 985 B1 discloses a fluid filter having a housing in which there is a receiving space for receiving a ring filter element, said space being closable by a cover. Furthermore, an inlet for crude fluid, an outlet for cleaned fluid and an outlet through which the receiving space can be emptied on removal of the cover are also provided. This outlet is at the bottom of the receiving space in the installed state of the fluid filter. In addition, a closure is provided on the ring filter element for closing the outlet when the ring filter element is inserted into the receiving space and the receiving space is closed by the cover. With the known fluid filter, said closure is formed by a journal arranged eccentrically to protrude axially away from the ring filter element. With the known fluid filter, the receiving space is closed by the cover from above, and the outlet is provided at the bottom of the receiving space in the housing. With the known fluid filter, to simplify locating and inserting the journal into the outlet, a concentrically arranged and helically ascending ramp is provided on the housing, such that the outlet is arranged between a lower end of the ramp and an upper end of the ramp. When the cover is screwed in place, the journal locates the outlet automatically and can penetrate into it and close it due to the rotational movement of the ring filter element and due to the journal sliding along the ramp. In an especially advantageous embodiment of the known fluid filter, the ramp and the journal can work together according to the lock-and-key principle in such a way that only a ring filter element provided with a journal adapted to the ramp can be used with the known fluid filter, such that the closure locates the outlet automatically and closes it when the cover is screwed into place. 
     DE 200 06 972 U1, DE 200 08 112 U1 and WO 00/62893 A1 disclose other fluid filters with which the cover closes the receiving space from underneath in the installed state such that the cover has the outlet arranged concentrically with the longitudinal central axis of the ring filter element and is closed from the outside by a closure in the form of a screw designed as a separate component. Before removing the cover, the receiving space can thus be emptied by removing the closure. 
     SUMMARY 
     The present invention relates to the problem of providing an improved embodiment or at least another embodiment for a fluid filter of the type defined in the introduction such that it will allow in particular a different installation situation for the fluid filter. 
     According to this invention, this problem is solved by the subject matters of the independent claims. Advantageous embodiments are the subject matter of the dependent claims. 
     The present invention is based on the general idea of integrating the outlet into the cover, and it is especially important here that the closure assigned to the outlet is still arranged on the ring filter element, so that the closure can open the outlet automatically on removal of the cover. Furthermore, it is proposed that the fluid filter be designed in such a way that when installed, the cover that closes the receiving space is arranged at the bottom of the housing. In this way, the outlet is automatically at a low location which facilitates emptying of the receiving space in removal of the cover. 
     In the case of the inventive fluid filter, the receiving space is emptied on removal of the cover through the outlet toward the outside so that the fluid flowing out through the outlet can be collected in an external container. It is advantageous here that the receiving space is largely emptied until the cover can be removed from the housing. Then, with the cover removed, the ring filter element can be replaced. It is especially advantageous here that it is possible to work comparatively cleanly when replacing the ring filter element because the closure is removed from the outlet on the inside of the outlet and not from the outside. Furthermore, this also prevents the closure from being forgotten when replacing the ring filter element. 
     In a preferred embodiment, the ring filter element is axially secured on the housing in such a way that when there is a relative axial movement between the cover and the housing that is performed to open the receiving space, the closure opens the outlet, in particular before the cover has been and/or can be removed from the housing. This means that the ring filter element remains on the housing when the cover is removed and is not necessarily removed along with the cover. This can simplify handling of the ring filter element. 
     The closure that is provided on the ring filter element may be formed by a journal protruding axially away from the ring filter element, such that the outlet then has an outlet opening into which the journal is inserted axially for closing the outlet. Alternatively, the closure formed on the ring filter element may also be formed by a cap that is open axially toward the outside, such that the outlet then has a connection that protrudes axially into the receiving space and penetrates axially into the cap to close the outlet. Although the embodiment using journals may perhaps be easier to seal, there is a reduced risk of damage to the ring filter element when it is replaced in a careless manner in the embodiment having a cap. 
     The outlet and the closure may be arranged concentrically on the cover and/or on the ring filter element. Alternatively, the outlet and closure may be arranged eccentrically on the cover and/or on the ring filter element. Both embodiments have certain advantages. 
     In the case of an eccentric arrangement of the outlet and the closure, according to an advantageous embodiment, a ramp arranged concentrically and ascending helically may be provided, as is known per se from EP 1 299 895 B1 which was cited in the introduction and which is herewith added to the disclosure content of the present invention through this explicit reference thereto. Depending on the embodiment, said ramp may be arranged either on the cover so that the outlet is arranged between a lower end of the ramp and an upper end of the ramp or on the ring filter element in such a way that the closure is arranged between a lower end of the ramp and an upper end of the ramp. The ramp simplifies the locating of the relative position between the closure and the outlet as is required for closing the outlet. 
     Furthermore, in another embodiment, it is possible to provide for the ramp and journal and/or the ramp and connection to be designed so that they cooperate according to the key and lock principle. Subsequently only a ring filter element provided with a journal adapted to the ramp and/or only a ring filter element provided with a ramp adapted to the connection can be used with the fluid filter in such a way that the closure locates the outlet automatically and closes it when the cover is screwed in place. Due to this embodiment, to secure proper functioning of the fluid filter, this should achieve the result that only the ring filter elements actually provided for the fluid filter may be used, e.g., to prevent inadvertent use of the wrong ring filter element. The exclusivity criterion “only” in the present context refers to the fact that the closure locates the outlet automatically and closes it when the proper and/or adapted ring filter element is used in screwing the cover on regularly—exceptions are of course also possible—whereas in the case of a ring filter element that is not adapted properly, if the closure is present it will not find the outlet and accordingly will not close it when screwing on the cover in the regular manner—and exceptions are also possible here. 
     Other important features and advantages of the present invention are derived from the dependent claims and the drawings and from the respective description of the figures on the basis of the drawings. 
     It is self-evident that the features mentioned above and those yet to be explained below may be used not only in the particular combination indicated but also in other combinations or alone without going beyond the scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Preferred exemplary embodiments of the invention are depicted in the drawings and explained in greater detail in the following description, where the same reference numerals are used to refer to the same or similar or functionally the same components. 
       In each, schematically 
         FIG. 1  shows a longitudinal section through a part of a fluid filter, 
         FIG. 2  shows a perspective view into a cover of the fluid filter, 
         FIGS. 3 through 10  each show a simplified longitudinal section in a lower partial area of the fluid filter in different embodiments, 
         FIG. 11  shows a greatly simplified top view of a ramp, 
         FIGS. 12 and 13  show greatly simplified longitudinal sections in the area of the ramp in different embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     According to  FIG. 1 , a fluid filter  1  comprises a housing  2  (shown here only in part) and at least one receiving space  3 . The receiving space  3  serves to receive a ring filter element  4  and can be closed with a cover  5 , which to this end can be attached to the housing  2 . The fluid filter  1  may preferably be designed as an oil filter for cleaning lubricating oil and may be provided in particular for internal combustion engines in motor vehicles. Alternatively, it is fundamentally also possible to design the fluid filter  1  as a fuel filter. Although in the embodiment shown here, the fluid filter  1  has only one receiving space  3  in or on its housing  2 , embodiments having two or more receiving spaces  3  are also possible. For example, an embodiment having three receiving spaces  3  is possible, in which case it is then possible to provide for two of the ring filter elements  4  to be arranged in parallel or in series with a main stream of the fluid to be cleaned, whereas the third ring filter element  4  is provided for cleaning a side stream. 
     The fluid filter  1  also comprises an inlet  6  for crude fluid, i.e., for fluid to be cleaned and an outlet  7  for clean fluid, i.e., for fluid that has been cleaned. The fluid flow occurring inside the fluid filter  1  during operation is indicated by arrows here. In the present case, the ring filter element  4  has flow passing through it radially from the outside to the inside, but essentially any other design is also conceivable. Furthermore, the fluid filter  1  has an outlet  8  through which the receiving space  3  can be emptied when the cover  5  is removed. When the fluid filter  1  as shown in  FIG. 1 , said outlet  8  is arranged at the bottom of the receiving space  3 . 
     The installed position illustrated here is characterized by an essentially vertical longitudinal central axis  9  of the ring filter element  4 . To the extent that this is an upright arrangement of the fluid filter  1 , in particular an upside down arrangement, which may also be referred to as a hanging arrangement. In this installed position, the cover  5  is arranged at the bottom of the housing  2  when it seals the receiving space  3 . Accordingly, the outlet  8  is designed in and/or on the cover  5 . The outlet  8  is expediently arranged in the bottom  10  of the cover  5  bordering the receiving space  3  at the bottom. In the preferred embodiments shown here, the receiving space  3  is largely designed inside the cover  5  so that the cover  5  is shaped essentially in a pot shape. Fundamentally, however, another embodiment is also possible, in which the receiving space  3  is mostly or completely designed in the inside of the housing  2 . 
     When installed, the ring filter element has a closure  11  at the bottom. In the completely assembled state shown here, the ring filter element  4  is inserted into the receiving space  3 , while the receiving space  3  is covered completely by the cover  5  and the closure  11  closes the outlet  8 . 
     The ring filter element  4  consists, for example, of a filter material  12 , which is arranged in a ring shape coaxially with the central longitudinal axis  9  and may consist of a pleated sheeting material, for example. In addition, the ring filter element  4  has an end disk on each of its axial end faces, namely a lower end disk  13  and an upper end disk  14 . The filter material  12  may be fixedly attached axially to the end disks  13 ,  14 , in particular by welding. 
     Furthermore, the ring filter element  4  may have a groove  15  on the inside radially on which the filter element  12  may be supported on the inside radially. The inner groove  15  has a plurality of openings (not shown in detail here) through which the cleaned fluid can enter the clean interior of the ring filter element  4  and can escape from the receiving space  3  through the outlet  7 . The closure  11  is preferably arranged on the lower end disk  13 . The closure  11  may be integrally shaped on the lower end disk  13 . It is likewise possible to manufacture the closure  11  as a separate component and attach it to the lower end disk  13 . 
     In the example shown in  FIG. 1 , the cover  5  has a mandrel  16  which is concentric with the central longitudinal axis  9  and, when installed, it protrudes into the inner groove  15  axially through a central opening  17  in the lower end disk  13 . To seal the crude side from the clean side, the lower end disk  13  may be provided with a suitable gasket (not shown here) on the inside radially. In another embodiment, instead of an open lower end disk  13 , a closed lower end disk  13  may also be provided. 
     Furthermore, the end disk  14  has a central opening  18  into which an outlet connection  19  formed on the housing  2  protrudes coaxially in the installed state. Here again, a seal is expediently provided on the crude side with respect to the clean side with the help of a gasket (not shown here), which is formed on the upper end disk  14 . 
     In the area of the upper end disk  14 , the ring filter element  4  is secured axially on the housing  2 . The holding force of this axial attachment between the ring filter element  4  and the housing  2  is designed to be larger than the holding force between the ring filter element  4  and the cover  5  of an axial attachment between the closure  11  and the outlet  8 . This achieves the result that with a relative axial movement between the cover  5  and the housing  2 , which is performed to open the receiving space  3 , the closure  11  opens the outlet  8 . This means that the ring filter element  4  does not follow the relative of the cover  5  but instead remains stationary in the axial direction in relation to the housing  2 . The cover  5  is preferably attached to the housing  2  by a screw connection  20 . Alternatively, essentially a different type of attachment may be selected, e.g., a bayonet closure. The screw connection  20  and/or the respective other type of fastening is preferably adapted, so that, when removing and/or screwing the cover  8  in place, the outlet  8  is opened even before the cover  5  can be completely removed from the housing  2 . The result is that the receiving space  3  is at least partially emptied through the outlet  8  by the time the cover  5  can be removed from the housing  2 . 
     The axial attachment of the ring filter element  4  to the housing  2  can be accomplished, e.g., with the help of a catch connection  21  which makes it possible to secure the ring filter element  4  detachably to the housing  2  in such a way that it can be removed from the housing  2  again nondestructively, or at least without destroying the housing  2 . The catch connection  21  shown here comprises, for example, a ring groove  22  that is formed on the outside of the outlet connection  19  radially and several catch bodies  23  that protrude radially toward the inside and are formed on the inner groove  15  in such a way that they are distributed in the circumferential direction and engage radially in the ring groove  22  from the outside. In this embodiment, the catch connection  21  is designed so that the ring filter element  4  can be rotated about its central longitudinal axis  9  in relation to the housing  2 , whereas it is secured on the housing  2  in the axial direction at the same time. 
     In the embodiment shown in  FIGS. 1 and 2 , the closure  11  is formed by a journal  24 , while the outlet  8  has an outlet opening  25 . The journal  24  engages in this outlet opening  25  to close the outlet  8 . The journal  24  may expediently therefore have a seal  26  that acts radially, e.g., an O-ring which cooperates with a wall of a channel section  27  of the outlet  8 . 
     Furthermore, in the embodiment according to  FIGS. 1 and 2  the outlet  8  is arranged on the cover  5  so that it is eccentric with respect to the central longitudinal axis  9 . Likewise, the closure  11  is arranged on the ring filter element  4  so that it is eccentric with regard to the central longitudinal axis  9 . To simplify the locating and closing of the outlet  8  with the closure  11  in this eccentric arrangement of the free will  8  and the closure  11 , in the embodiment according to  FIGS. 1 and 2 , a ramp  28  is also provided and is arranged concentrically with regard to the central longitudinal axis  9  and rises or falls in a helical pattern, depending on the system of reference. In the example according to  FIGS. 1 and 2 , this ramp  28  is arranged on the cover  5 , namely on the bottom  10  on a side facing the receiving space  3  so that the outlet  8  is situated between a lower end  29  of the ramp and an upper end  30  of the ramp. 
     At last the embodiment of the fluid filter  1  illustrated in  FIGS. 1 and 2  functions as described below. 
     Starting from the installed state illustrated in  FIG. 1 , for example, a used ring filter element  4  is to be replaced by a new one. To do so, the cover  5  is removed from the housing  2 , e.g., by unscrewing it from the housing  2 . The cover  5  may be equipped externally with a polygonal insert bit  31  on its bottom  10  that allows the use of a suitable tool. When the cover  5  is screwed on, the cover  5  rotates about the central longitudinal axis  9  on the one hand, while on the other hand, distancing itself from the housing  2  in the axial direction. The ring filter element  4  is coupled to the housing  5  in a rotationally fixed manner via the eccentric journal  24  engaging in the outlet opening  25  so that the ring filter element  4  copies the rotational movement of the cover  5 . The ring filter element  4  can be rotated about its central longitudinal axis  9  with respect to the housing  2 , which is implemented in the area of the axial attachment, i.e., here by the catch connection  21 . However, the ring filter element  4  remains stationary axially in relation to the housing  2  so that the housing  2  is also moved axially in relation to the ring filter element  4  in screwing it on. In this way, the journal  24  is gradually pulled out of the outlet  8  with respect to the receiving space  3  and toward the interior. As soon as the outlet  8  has been opened, the receiving space  3  can run outward through the outlet  8  into an environment  32  of the fluid filter  1 . The fluid running out is then collected in a suitable container. When the outlet  8  is opened, the cover  5  is still on the housing  2  and must also be screwed on. As soon as the screw connection  20  releases the cover  5 , it can be removed downward from the housing  2  while the ring filter element  4  remains on the housing  2 . The receiving space  3  is then open and then the ring filter element  4  is accessible for replacement. In replacing the ring filter element  4 , the old ring filter element  4  is removed from the housing  2 . There are now several options for mounting the new ring filter element  4 . First, the new ring filter element  4  can be inserted easily into the cover  5  and it is not necessary for the journal  24  to be already engaged in the outlet opening  25 . Instead it is expected that the journal  24  will come in contact axially with the ramp  28  at any other location or may even be a distance away from the latter because the ring filter element  4  must be placed on the mandrel  16  against resistance. When screwing the cover  5  into the housing  2 , the ring filter element  4  is placed on the outlet connection  19 , while at the same time the mandrel  16  penetrates more deeply into the ring filter element  4 . As soon as the journal  24  comes in contact with the ramp  28  axially, the journal  24  may slide along the ramp  28  in the direction of the lower end  29  of the ramp due to the rotational movement of the cover  5 . As soon as the journal  24  passes over the lower end  29  of the ramp, it becomes aligned with the outlet opening  25 . Since the upper end  30  of the ramp prevents further rotational adjustment between the ring filter element  4  and the cover  5 , further tightening of the cover  5  by tightening the screws leads to entrainment of the ring filter element  4 , so that it also rotates with the cover  5  and thereby moves in the radial direction in relation to the cover  5  and/or in relation to the housing  2 . At the latest when the cover  5  has been completely screwed on, the journal  24  is completely inserted into the outlet  8  and the catch bodies  23  are engaged in the ring groove  22 . It is thus essentially possible to tighten the ring filter element  4  manually in relation to the cover  5  when screwing it into the cover  5 , so that the journal  24  slides along the ramp  28  and penetrates into the outlet  8 . Next the cover  5  can be mounted on the housing  2  with the premounted ring filter element  4 . It is likewise possible to first attach the ring filter element  4  to the housing  2 , i.e., to engage it on the outlet connection  19 . Here again, when subsequently screwing the cover  5  in place, with a suitable adaptation of the slope of the ramp to the pitch of the thread of the screw connection  20 , it is possible to achieve the result that the cover  5  rotates together with the ring filter element  4  only when the journal  24  is aligned with the inlet opening  25 . 
       FIGS. 3 through 10  illustrate several different exemplary embodiments of the fluid filter  1 , although without any claim that this is complete and without restricting the general scope in any way. 
     In the embodiments of  FIGS. 3 ,  4  and  8 , as in the example according to  FIG. 1 , the closure  11  is designed as a journal  24  protruding axially at the bottom away from the ring filter element  4 . Accordingly in these embodiments, the outlet  8  is equipped with an outlet opening  25  into which the journal  24  penetrates axially to close the outlet  8 . In contrast with that, in the embodiments according to  FIGS. 5 through 7 ,  9  and  10 , the closure  11  is formed by a cap  33 , which is open toward the outside axially, i.e., away from the ring filter element  4 . In these embodiments, the outlet  8  is provided with a connecting piece  34 , which protrudes axially into the receiving space  3  and penetrates axially into the cap  33  to close the outlet  8 . The cap  33  is designed with a sleeve shape in the embodiments according to  FIGS. 5 ,  6  and  9 , such that the cap  33  in these embodiments protrudes axially away from the ring filter element  4  and/or from its lower end disk  13 . In the embodiments according to  FIGS. 7 and 10 , the cap  33  is designed with a pot shape, such that the cap  33  protrudes axially into the respective ring filter element  4 . As in the embodiment according to  FIG. 7 , it is also possible to provide for the filter material  12  to be cut to size accordingly in the area of the cap  33 . It is likewise possible to provide the lower end disk  13  axially with a suitable thickness to integrate the cap  33  into it. In the embodiment shown in  FIG. 10 , the cap  33  is arranged on the inside with respect to the filter material  12  so that the structural adaptation of the ring filter element  4  is comparatively small. Likewise, an embodiment in which the cap  33  protrudes axially into the ring filter element in a pot-like manner and, on the other hand, also protrudes axially away from the ring filter element  4  like a sleeve is also possible. 
     In the embodiments in  FIGS. 3 through 7 , the outlet  8  and the closure  11  are arranged on the cover  5  and/or on the ring filter element  4 , so that they are eccentric with respect to the central longitudinal axis  9 . In the embodiments according to  FIGS. 8 through 10 , the outlet  8  is arranged on the cover  5  so that it is concentric with the central longitudinal axis  9 , while at the same time, the respective closure  11  is arranged on the ring filter element  4  so that it is concentric with regard to the central longitudinal axis  9 . The concentric arrangement of the outlet  8  and the closure  11  may also be advantageous with regard to locating the correct relative position for the closure  11  in relation to the outlet  8  for closing the outlet  8 . 
     To also simplify the process of locating the correct relative position between the closure  11  and the outlet  8  for closing the outlet  8  even with an eccentric arrangement of the outlet  8  and the closure  11 , the embodiments according to  FIGS. 4 ,  6  and  7  are each equipped with a ramp  28 . Said ramp  28  is arranged on the cover  5  in the embodiment shown in  FIG. 4  as well as that in  FIG. 1 , so that the outlet  8  is situated between the lower end  29  of the ramp and the upper end  30  of the ramp. In the embodiments according to  FIGS. 6 and 7 , however, the respective ramp  28  is situated on the ring filter element  4 , namely preferably on the lower end disk  13  such that the ramp  28  protrudes outward axially, i.e., facing away from the ring filter element  4 . The arrangement of the respective ramp  28  on the ring filter element  4  is such that the respective closure  11  is again situated between the lower end  29  of the ramp and the upper end  30  of the ramp. 
     The embodiments equipped with a ramp  28 , in particular those in  FIGS. 1 ,  2 ,  4 ,  6  and  7 , can be designed expediently according to  FIGS. 11 through 13  such that the respective ramp  28  and the journal  24  and/or the ramp  28  and the connecting piece  34  work together according to the lock-and-key principle. This lock-and-key principle means that only such ring filter elements  4  in which the journal  24  is adapted to the ramp  28  of the cover  5  and/or in which the ramp  28  formed on the ring filter element  4  is adapted to the connecting piece  34  of the cover  5  can be used properly with the fluid filter  1 . The proper use that is relevant here means that the respective closure  11  locates the outlet  8  automatically and closes it when attaching, i.e., turning the cover  5 . When the ring filter elements are not specifically adapted to the fluid filter  1 , the lock-and-key principle prevents any closure that may optionally be provided from being able to automatically locate and close the outlet  8  when screwing on the cover  5 . This should achieve the result that precisely adapted ring filter elements  4  can be used only for the fluid filter  1 , e.g., to be able to ensure a proper filtration function. 
     To implement the lock-and-key principle, an insertion contour having guide bodies  35  may be provided on the respective lower end  29  of the ramp according to  FIGS. 11 through 13 , for example; these guide bodies may in turn be arranged on one or both sides of the ramp  28  and protrude axially beyond the ramp  28 . A journal  24  sliding downward along the ramp  28  and/or a connecting piece  34  sliding downward along the ramp  28  may reach the outlet opening  25  and/or the cap  33  only if it has a protrusion  36  that protrudes axially away from the respective closure  11  and is adapted to the guide bodies  35 . This protrusion  36  may be, for example, a pin-shaped or web-shaped lug that establishes contact between the journal  24  and/or the connecting piece  34  and the ramp  28 . This protrusion  36  is dimensioned axially in such a way that it can lift the journal  24  and/or the connecting piece  34  beyond the guide elements  35 . This means that the journal  24  or connecting piece  34  sliding over the protrusion  36  on the ramp  28  is at a distance axially from the guide elements  35  such that it can be aligned with the outlet opening  25  and/or the cap  36  passing by the guide bodies  35 . According to  FIGS. 11 through 13 , the protrusion  36  may come in contact with the ramp  28  between the guide elements  35  and thereby allow the journal  24  and/or the connecting piece  34  to slide on the ramp. 
     Moreover, with regard to the lock-and-key principle and its implementation, reference is made to EP 1 229 985 B1, which was cited in the introduction and is herewith appended to the present invention through explicit reference to the disclosure content.