Abstract:
A suction filter providing a heat transfer pathway therein is provided. The suction filter includes a support structure, an inlet connected to the support structure, a filter element connected to the support structure, and a thermally conductive element that communicates with an interior portion of the suction filter. The filter element is configured to filter a fluid as it passes through the filter element into an interior portion of the suction filter. Also, the thermally conductive element extends from the interior portion of the suction filter to an exterior portion of the suction filter. The thermally conductive element is configured to transfer heat obtained external the suction filter to the interior portion of the suction filter in order to provide heat to the fluid in the interior portion of the suction filter.

Description:
[0001]    The present application claims the benefit of U.S. Provisional Patent Application Serial No. 61/179883, entitled “SUCTION FILTER DESIGN FOR FLUID THAWING,” filed on May 20, 2009, and which is incorporated herewith by reference in its entirety. 
     
    
     FIELD 
       [0002]    A filter for use within a fuel tank is disclosed that provides an improved structure for providing a heat transfer pathway to the inside of the filter. 
       BACKGROUND 
       [0003]    Conventional suction filters with depth filter media for use inside a fuel tank have shown to be problematic when the fluid inside the filter freezes. Particularly in urea fuel tanks, the use of depth filter media in conventional suction filters have been found to act as an insulator to the fluid (i.e., urea) inside the suction filter, thereby preventing heat from transferring to the inside of the suction filter even if an active heating unit is installed within the fuel tank. This can be problematic as urea freezes at relatively high temperatures and thus requires a heating system to thaw the urea prior to the urea being drawn from the fuel tank into a fuel pump. Accordingly, a fuel pump drawing urea from the conventional depth filter media suction filter will not have thawed urea to draw from. 
       SUMMARY 
       [0004]    The following technical disclosure describes an improved filter design for fluid thawing by providing heat into the interior of the filter. The technical disclosure can be applied to a variety of different filters including, for example, suction filters and the like. 
         [0005]    In some embodiments, an improved suction filter design that provides heat into the interior of a depth filter media of the suction filter is provided. In other embodiments, an improved suction filter design that provides heat into the interior of the suction filter that uses a surface media. The heat provided in the interior of the filter can be used to heat many types of fluids that can be located within the interior of the filter including, for example, water and urea. 
         [0006]    In one embodiment, a suction filter providing a heat transfer pathway therein is provided. The filter includes a support structure, an inlet and a filter media. The inlet is connected to the support structure and configured to connect to a fuel pump. The filter media is also connected to the support structure and filters a fluid as it passes through the filter media into an interior portion of the suction filter. An inside surface of the support structure defines the interior portion of the suction filter and the support structure is configured to allow a thermally conductive element to enter the interior portion. The thermally conductive element transfers heat obtained external the suction filter to the interior portion of the suction filter in order to provide heat to the fluid in the interior portion of the suction filter. 
         [0007]    In another embodiment, a suction filter providing a heat transfer pathway therein is provided. The suction filter includes a support structure, an inlet connected to the support structure and configured to connect to a fuel pump, a filter media connected to the support structure that filters a fluid as it passes through the filter media into an interior portion of the suction filter, and a thermally conductive element that communicates with an interior portion of the suction filter and an exterior portion of the suction filter. The filter media is configured to filter a fluid as it passes through the filter element into an interior portion of the suction filter. Also, thermally conductive element transfers heat obtained external the suction filter to the interior portion of the suction filter in order to provide heat to the fluid in the interior portion of the suction filter. 
         [0008]    In yet another embodiment, a method for providing heat to a fluid contained within an interior portion of a suction filter is provided. The method includes heating an exterior portion of a thermally conductive element. The exterior portion of the thermally conductive element is located at an exterior portion of the suction filter. The method also includes transferring heat from the exterior portion of the thermally conductive element to an interior portion of the thermally conductive element located in the interior portion of the suction filter. The method further includes the heat transferred to the interior portion of the thermally conductive element providing heat to the interior portion of the suction filter. 
         [0009]    In one embodiment, the thermally conductive element is part of the support structure of the suction filter. In another embodiment, the thermally conductive element is not part of suction filter. 
         [0010]    In one embodiment, the thermally conductive element is also connected to the filter media. 
         [0011]    In one embodiment, the filter includes an interior cavity and openings at opposing ends of the suction filter for allowing a heating unit to pass therein. 
         [0012]    In one embodiment, the filter includes an interior portion and openings at opposing ends of the filter for allowing the thermally conductive element to enter and exit the interior portion of the filter. In another embodiment, the suction filter includes an opening only at one of the opposing ends of the filter that allows the thermally conductive element to enter the interior portion of the filter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  illustrates a perspective view of a suction filter providing a heat transfer pathway therein, according to one embodiment. 
           [0014]      FIG. 2  illustrates a partial perspective view of one side of an embodiment of a suction filter providing a heat transfer pathway therein, according to another embodiment. 
           [0015]      FIG. 3  illustrates a flow chart of how a suction filter thermally transfers heat from outside the suction filter to the interior of the suction filter, according to one embodiment. 
           [0016]      FIG. 4  illustrates a perspective view of a suction filter in a closed position that provides a heat transfer pathway therein, according to another embodiment. 
           [0017]      FIG. 5  illustrates a perspective view of a suction filter in an open position that provides a heat transfer pathway therein. 
           [0018]      FIG. 6  illustrates a sectional side view of a suction filter in a closed position that provides a heat transfer pathway therein. 
           [0019]      FIG. 7  illustrates a perspective view of a suction filter that provides a heat transfer pathway therein according to another embodiment. 
           [0020]      FIG. 8  illustrates a sectional side view of a suction filter that provides a heat transfer pathway therein. 
           [0021]      FIG. 9  illustrates a flow chart of how a suction filter thermally transfers heat from outside the suction filter to the interior of the suction filter, according to another embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    The suction filters described herein can generally provide an improved structure for providing a heat transfer pathway to the inside of the filter. The embodiments discussed herein are directed to a depth media suction filter for use inside a urea fuel tank. However, the improvements described herein may be also used for suction filters using a surface media and may be used to provide heat inside the suction filter for heating other types of fluids besides urea. 
         [0023]      FIG. 1  illustrates a perspective view of one embodiment of a suction filter  10  providing a heat transfer pathway therein. The suction filter  10  includes a support structure  12  surrounded by depth filter media  14 . The support structure  12  includes an inlet  16  and a thermally conductive element  20 . The inlet  16  is configured to connect to a fuel pump and allow the fuel pump to draw filtered urea from an interior cavity (not shown) of the suction filter  10 . The thermally conductive element  20  includes an exterior appendage portion  22  connected to a plurality of interior rib portions  24 . 
         [0024]      FIG. 2  illustrates a partial interior view of another embodiment of a suction filter  30  providing a heat transfer pathway therein. The suction filter  30  includes a support structure  32  molded to depth filter media  34 . The support structure  32  includes an inlet  36  and a thermally conductive element  40 . The thermally conductive element  40  includes an exterior appendage portion  42  connected to an interior rib portion  44 . The exterior appendage portion  42  is integrally formed with the inlet  36 . The rib portion  44  and a portion of the appendage portion  42  are molded to an interior portion of the depth filter media  34 . 
         [0025]    The interior rib portion  44  includes a spine  46  extending along the length of the depth filter media  34  and a plurality of ribs  48  extending perpendicularly from the spine  46 . The positioning of the spine  46  and the ribs  48  allow the interior rib portion  44  to provide heat to a substantial portion of the interior of the suction filter  30 . 
         [0026]      FIG. 3  illustrates a flow chart  50  of one embodiment of how a suction filter similar to the suction filter  10  shown in  FIG. 1  and the suction filter  30  shown in  FIG. 2  thermally transfers heat from outside the suction filter to the interior of the suction filter. The flowchart  50  begins at step  52  whereby a heating unit located inside the fuel tank in which the suction filter is located, is used to heat the urea stored in the fuel tank. 
         [0027]    At step  54 , the heat from the heated urea stored in the fuel tank is transferred to the exterior appendage of the thermally conductive element. 
         [0028]    At step  56 , the heat from the exterior appendage portion of the thermally conductive element is transferred to the interior rib portion of the thermally conductive element. 
         [0029]    At step  58 , heat transferred to the interior rib portion of the thermally conductive element is now able to thaw urea located in the interior of the suction filter. 
         [0030]      FIG. 4  illustrates a perspective view of another embodiment of a suction filter  60  providing a heat transfer pathway therein. The suction filter  60  includes a first housing portion  62  attached to a second housing portion  64 . The first housing portion  62  and the second housing portion  64  include openings  66  covered with depth filter media  68 . The first housing portion  62  also includes an inlet  70 . The first housing portion  62  and the second housing portion  64  together define a support structure of the suction filter  60 . 
         [0031]    The suction filter  60  has a first end  72  and a second end  74 . Both the first end  72  and the second end  74  include openings  76  that allow a heater unit A to pass through an interior cavity  78  (shown in  FIGS. 5 and 6 ) of the suction filter  60 . The interior cavity  78  is configured for storing fluid filtered by the depth filter media  68  and to provide a passageway for allowing the heater unit A to pass through the suction filter  60 . 
         [0032]    Also, as shown in  FIG. 5 , the first housing portion  62  is attached to the second housing portion  64  via a hinge  82 . When assembling the suction filter  60  to fit around the heater unit A inside a fuel tank, an opposing end  84  of the first housing portion  62  and an opposing end  86  of the second housing portion  64  can be attached using a clipping mechanism or the like. Thus, the heater unit A effectively becomes a thermally conductive element for the suction filter  60 . In some embodiments, the interior cavity  78  can also include other thermally conductive elements that are attached to an interior surface of the first housing portion  62  and/or the second housing portion  64  and configured to be in contact with the heater unit A to improve the thermal conduction of heat throughout the interior cavity  78  of the suction filter  60 . 
         [0033]      FIG. 7  illustrates a perspective view of yet another embodiment of a suction filter  90  providing a heat transfer pathway therein. The suction filter  90  includes a housing portion  92  that includes openings  94  covered with depth filter media  96 , a thermally conductive element  98  passing through an interior cavity  104  (shown in  FIG. 8 ) and projecting out from opposing ends  100  of the housing portion  92 . The housing portion  92  defines a support structure of the suction filter  90 . The suction filter  90  also includes an inlet  102 . The ends of thermally conductive element  98  are configured to removably fit or attach onto a heater unit A. In one embodiment, the ends of the thermally conductive element  98  are configured to pinch the heater unit A. Also, in some embodiments, the thermally conductive element  98  projects out of only one of the opposing ends  100  of the housing portion  92 . 
         [0034]    The interior cavity  104  is configured for storing fluid filtered by the depth filter media  96  and for allowing the thermally conductive element  98  to pass through the suction filter  90 . The thermally conductive element  98  has a ribbon-like shape in the interior cavity  104  to improve the thermal conduction of heat throughout the interior cavity  104 . 
         [0035]      FIG. 9  illustrates a flow chart  110  of one embodiment of how a suction filter similar to the suction filter  90  shown in  FIGS. 7 and 8  thermally transfers heat from outside the suction filter to the interior of the suction filter. The flowchart  110  begins at step  112  whereby a heating unit located inside the fuel tank is connected to the suction filter via a thermally conductive element that passes through an interior cavity of the suction filter. 
         [0036]    At step  114 , while the heater unit provides heat for the urea stored in the fuel tank, the heater unit also provides heat along the entire portion of the thermally conductive element, thereby transferring heat to the interior cavity of the suction filter. 
         [0037]    At step  116 , heat transferred to the thermally conductive element thaws urea located in the interior cavity of the suction filter. 
         [0038]    In some embodiments, the thermally conductive elements  20 ,  40  and  98  are made from a thermally conductive plastic or metallic material that contains heat-conductive additives of graphite such as, for example, carbon fibers, carbon particles, ceramic, metallic fillers, et. . . . In other embodiments the thermally conductive elements  20 ,  40  and  98  are formed with other thermally conductive materials. 
         [0039]    Thus, the thermal conductivity of the thermally conductive elements  20 ,  40  and  98  can vary significantly based on the materials used. For example, some unfilled thermoplastics have a thermal conductivity as low as 0.2 W/mK and some filled thermoplastics filled with extrusion-grade aluminum alloys having a thermal conductivity of up to 150 W/mK. Typically, most thermally conductive plastic compounds have a thermal conductivity in the range of 1-10 W/mK and most die-cast metal alloys are in the 50-100 W/mK range. 
         [0040]    Accordingly, any number of thermally conductive plastic or metallic materials may be used for the thermally conductive elements  20 ,  40  and  98  depending on, for example, the thermal conductivity required, the structural quality of the material, and the cost of the material. For example, in some embodiments the thermally conductive elements  20 ,  40  and  98  are formed using a lower cost material such as ceramic or metal additives to provide thermal conductivity up to 2 W/mK. In other embodiments, the thermally conductive elements  20 ,  40  and  98  are formed using a high performance material such as a carbon fiber to achieve thermal conductivities up to 10 W/mK. Also, in some other embodiments, the thermally conductive elements  20 ,  40  and  98  include nylon 6 and 66, Polypropylene (“PP”) and Polyphenylene Sulfide (“PPS”) that, depending on the resin type and filler, have thermal conductivities up to 60 W/mK. Further, in yet some other embodiments, the thermally conductive elements  20 ,  40  and  98  are formed using an extrusion-grade aluminum alloy to provide thermal conductivity near 150 W/mK. 
         [0041]    The above examples of materials used for the thermally conductive elements  20 ,  40  and  98  are merely several exemplary examples that may be used, and in other embodiments other materials may be used that provide effective thermal conduction to an interior cavity of a suction filter. Also, filled thermoplastics filled with thermally conductive materials such as ceramic, metallic fillers, carbon particles, carbon fibers, etc. can also used to reduce electric consumption by the heating system. 
         [0042]    The invention may be embodied in other forms without departing from the spirit or novel characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.