Abstract:
A liquid filter with a filter housing ( 9 ) with a filter element ( 8, 108, 208 ) arranged within. Within the filter element ( 8, 108, 208 ) a standpipe ( 3, 103, 203 ) is arranged. This standpipe is sealing connected with the filter element, whereby in the connecting range between standpipe and filter element a sealing element ( 15, 115 ) is arranged for sealably closing a discharge hole ( 11 ) in the housing ( 9 ). The sealing element ( 15, 115 ) seals the discharge hole and also sealably separates a clean side from a contaminated fluid side by sealing between the standpipe and the filter housing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 USC 119 of foreign application 10 2009 032 702.9 filed in Germany on Jul. 9, 2009, and which is hereby incorporated by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The invention relates to a liquid filter, in particular an oil filter. 
       BACKGROUND OF THE INVENTION 
       [0003]    Fluid filters, in particular oil filters, in which the filter insert is designed to be separated from the filter housing, are used in motor vehicles and industrial motors. The filter has a filter housing that is separable along an interface, wherein two housing components of the filter housing are sealed to one another along an interface by means of a gasket. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the present invention is to improve a liquid filter, in particular an oil filter, with respect to the prior art. This objective is achieved by a filter having the characteristics of claim  1 . 
         [0005]    The liquid filter according to the invention has a filter housing with a filter element and a standpipe provided inside a filter element, as well as a sealing element that tightly seals a discharge hole in the filter housing for a filter element inserted into the housing in a simple manner in a first operation, through which the liquid present in the housing during removal of the filter element is able to flow out of the housing. In a second operation the sealing element seals the clean side from the contaminated side between the standpipe and housing. The standpipe is sealed tightly to the filter element. 
         [0006]    The liquid filter has a filter housing with a contaminated liquid inlet and a clean liquid outlet, as well as a filter element arranged in the filter housing for cleaning a liquid, formed, for example, from a filter medium that is assembled in a zig-zag manner into a cylinder with end plates arranged frontally, known to practitioners in the field as circular elements. A standpipe is located inside the filter element. 
         [0007]    The sealing element for closing the discharge hole in the housing is located in the connection region between standpipe and filter element, so that, the discharge hole is unblocked and the liquid is able to flow out of the housing when the filter element is removed for maintenance during filter exchange. The discharge hole consists of one or a plurality of holes located at a distance from the central axis of the filter element. 
         [0008]    When the filter element is installed, the sealing element seals the discharge hole in the filter housing and simultaneously seals it between the clean and contaminated sides of the filter element against the housing. 
         [0009]    In a preferred embodiment, the sealing element is located on the front face of the standpipe turned toward the discharge hole. The standpipe preferentially has a receiving area that is enlarged in the radial direction, which accepts the sealing element on the one side and the end plate of the filter element on the axially opposite side. 
         [0010]    The contaminated side is radially sealed from the clean side along the circumferential outer wall of the standpipe with respect to the inside of the filter element in a common gasket region between the standpipe and the filter element, in order to prevent leakage along the contact region between the standpipe and filter element. The filter element can be axially displaced over the length of the common sealing point along the standpipe in order to compensate for tolerances. 
         [0011]    In an alternative embodiment, the sealing element is arranged on one of the end plates of the filter element facing the discharge hole. The sealing element is attached to the end plate and is exchanged with the filter element during servicing. 
         [0012]    The sealing element is advantageously formed as a circumferential flat ring or disk, so that a discharge hole seal is assured irrespective of the angular position of the filter element or the standpipe about the longitudinal axis. Angular positioning of the sealing element is thus unnecessary when the filter element is inserted into the liquid filter, and the filter element can be installed independent of the angular position. 
         [0013]    In a preferred embodiment, the sealing element is formed as an elastomer ring punched from tubing. ACM [polyacrylate rubber] is a particularly well suited material for the sealing element. 
         [0014]    In a preferred embodiment, the standpipe provided inside the filter element, through which the clean liquid flows, is provided with a dirt cover. This dirt cover can, for example, be a mesh screen, and inhibits the inflow of dirty liquid into the clean liquid outlet when a filter insert is absent. 
         [0015]    In a preferred embodiment, the standpipe is delivered, installed, and disassembled as a component of the filter element. In this embodiment, the gasket is arranged on the standpipe, and is thus easy to install. 
         [0016]    The standpipe can be inserted into a filter element, connected and/or secured to the filter element during fabrication of the filter element, so that the standpipe is exchanged during the exchange of the filter element without additional manual effort. The sealing element on the standpipe is thus exchanged with it. 
         [0017]    The standpipe is preferentially pressed against the housing with a force in the direction of the centerline of the filter element to compress the gasket against the housing to achieve an improved seal between the clean region and contaminated region in the region of contact of the standpipe to the housing, and to assure the secure closure of the discharge hole. This force is preferably applied by a spring, in particular by a coil spring that is mounted on the cover of the filter housing. 
         [0018]    In an alternative embodiment, the filter element is pressed axially by a force in the direction of the discharge hole. The spring is supported on a cover of the filter housing. This force causes the gasket held in the end plate of the filter element to be compressed, and thereby makes the seal between the clean region and the contaminated region in the region of contact of the standpipe to the housing. The discharge hole in the housing is covered or closed at the same time. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The accompanying Figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
           [0020]    Features of the present invention, which are believed to be novel, are set forth in the drawings and more particularly in the appended claims. The invention, together with the further objects and advantages thereof, may be best understood with reference to the following description, taken in conjunction with the accompanying drawings. The drawings show a form of the invention that is presently preferred; however, the invention is not limited to the precise arrangement shown in the drawings. 
           [0021]      FIG. 1  depicts a schematic sectional view of a filter insert of an oil filter in a housing, consistent with the present invention; 
           [0022]      FIG. 2  depicts a schematic sectional view of a filter insert having a standpipe according to an alternate embodiment of the present invention; and 
           [0023]      FIG. 3  is schematic sectional view of a filter insert having a standpipe and installed in a housing, illustrating spring loading of the filter insert or stand pipe, consistent with aspects of the present invention. 
       
    
    
       [0024]    Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. 
       DETAILED DESCRIPTION 
       [0025]    Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of apparatus components related to a replaceable filter element arranged on or secured to a standpipe including a sealing element closing a discharge hole in the housing. Accordingly, the apparatus components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
         [0026]    In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. 
         [0027]      FIG. 1  shows a schematic view of a housing  9  of an oil filter that has a contaminated oil inlet  10  and a clean oil outlet  12 , and is closed with a cover  218  ( FIG. 3 ). A tubular shaped filter element  8  is located inside the housing, which is assembled from a zig-zag shaped folded filter medium, and has facing end plates  6  and  7 . The filter element  8  may have a cylindrical shape or any other shape that defines an axially aligned cavity within the filter element  8  into which a standpipe  3  may be received. The contaminated oil flows through the filter element along arrows  4  and  5 , is cleaned and deposited in the center of the filter element  8 , itself above the clean oil discharge  12 . 
         [0028]    An additional discharge is provided on the housing  9  in the form of a discharge hole  11 , which assures that oil still present during the removal and exchange of filter element  8  can flow out of the housing in a downward direction. 
         [0029]    A standpipe  3  is provided inside the filter element  8  through which the clean oil flows, and which is provided with a dirt cover  14 . This dirt cover can, for example, also be a mesh screen, and inhibits the inflow of dirty oil into the clean oil outlet when a filter insert is missing. 
         [0030]    The filter element  8  is loaded by means of a coil spring, not shown here, with a force F 1  from above. This coil spring is supported on the housing  9 , specifically on an interior of the cover  218  ( FIG. 3 ). This force produces a seal between the clean oil region and the contaminated oil region in the gasket region  15 , and the discharge hole in the housing is covered or closed. This sealing region can be improved by means of an elastomer disk. As long as the standpipe  3  is delivered as a component of the filter element, and is installed and disassembled into the housing together with the filter element, then as the gasket  15  is located on the standpipe  3  it is thus easy to install. 
         [0031]    The contaminated side is radially sealed from the clean side along the circumferential outer wall of the standpipe  3  with respect to the inside of the filter element  8  at a sealing point  13  between the standpipe  3  and the filter element  8 . The filter element  8  can be axially displaced along the standpipe in order to match tolerances. This sealing point is formed by joining the standpipe in the filter element, for example, by seating the standpipe and/or end plate of the filter element in the region of the sealing point. 
         [0032]    In the embodiment shown, the standpipe  3  has an enlarged diameter in the region of the end plate  6  of the filter element  8 , so that the lower end plate  6  of the filter element is held by the standpipe  3 . 
         [0033]    Alternatively, the standpipe  3  can be designed as a unitary or one-piece component of the lower end plate  6 , so that the gasket  15  is mounted on the end plate. 
         [0034]    As has already been mentioned, the standpipe  3  has a dirt screen or a dirt cover  14 . The standpipe shown here can be inserted into a filter element, or connected with the filter element during filter element fabrication, so that the standpipe  3  can be exchanged without additional manual effort when exchanging the filter element. 
         [0035]      FIG. 2  shows a section through a filter element  108  with the end plates  106  and  107 , which can be inserted into a housing  9  (not shown in this figure). A standpipe  103  is arranged inside the filter element  108  through which the clean oil flows. The standpipe  103  has spacers  116  oriented radially in the outward direction for guiding and/or strengthening the filter element  108  in the form of ribs, which simultaneously guides the oil discharged from the filter element  108  to flow between the filter element  108  and standpipe  103  and then enter the standpipe  103  to flow downwards to the clean oil outlet (such as clean oil outlet  12  in  FIG. 1 ). 
         [0036]    The standpipe  103  is loaded with a force F 2  from above, by means of a coil spring  219  ( FIG. 3 ) and pressed against the housing  9 . This coil spring is supported on an inside surface of the cover  218  of the housing  9 . This force produces a seal between the clean oil region and the contaminated oil region in the region of a sealing element  115 . 
         [0037]    The discharge hole  11  in the housing  9  is simultaneously covered or closed by the force F 2  acting on the sealing element  115 . This sealing element can be designed as a gasket in the form of a flat elastomer ring. The sealing element  115  located on the standpipe  103  and is thus easy to install together with the standpipe  103  on the filter. 
         [0038]    The standpipe  103  shown can be inserted into a filter element  108  or connected with a filter element  108  during fabrication of the latter, so that the standpipe  3  can be exchanged without additional manual effort when the filter element is exchanged. 
         [0039]      FIG. 3  depicts a schematic view of a housing (such as housing  9  of  FIG. 1  and  FIG. 2 ) comprising a housing cover  218  and a housing based  220 . A replaceable (or exchangeable) cylindrical filter element  208  is replaceably received in the housing  9  (removable cover  218  plus base  220 ). The filter element  203  is arranged on or in other aspects, mounted or secured to a standpipe  203 . The filter element  208  has an upper end cap  207  secured to an end face of the filter media of the filter element. Either one of or both of the filter element end cap  207  or the standpipe  203  are loaded by a spring  219  (loading force shown by F 1  in  FIG. 1  or F 2  in  FIG. 2 ). The spring  219  is supported against the interior of the cover  218  and compressibly loads the filter element  208  and/or standpipe  203  in an axial direction to compress the gasket ( 15 ,  115 ) to sealably close over the discharge hole  11  of the housing  9 . 
         [0040]    In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.