Abstract:
A filter element is described that includes an endplate that also serves as the lid or cover for the filter housing. The combined endplate/lid includes a central hole that is closed to fluid flow when the proper filter element-housing combination is used. Various embodiments for different functional uses of the central hole are also described.

Description:
FIELD 
       [0001]    A filter element that is removably installable within a filter housing for filtering a fluid is described. The filter element has a combined filter media endplate/housing lid with a central hole that can provide a number of functionalities. 
       Background 
       [0002]    The use of inappropriate replacement filter elements is a growing problem for equipment operators and manufacturers. For example, in high pressure common rail fuel systems for diesel engines, fuel cleanliness specifications are extremely tight and specialized filters are required to maintain these conditions. The use of inappropriate filters with lower performance standards in place of the proper filter can lead to premature engine failure and, in extreme cases, result in increased warranty claims. 
         [0003]    The design of filter elements to discourage intentional or inadvertent use of inappropriate filters, such as those with unacceptable removal characteristics, pressure drop or life, is known. Many such designs aim to prevent the use of inappropriate filter elements, or at the very least hamper the functionality of inappropriate filter elements. 
         [0004]    Therefore, it is desirable to have a means to ensure that the proper filter is installed and used. It is further desirable that this means provide additional functionality to the filter or equipment, and that the design of the filter element be simplified. 
       Summary 
       [0005]    A filter element is described that includes an endplate that also serves as the lid or cover for the filter housing. The combined endplate/lid includes a central hole that is closed to fluid flow when the proper filter element-housing combination is used. Various embodiments for different functional uses of the central hole are described. 
         [0006]    The described filter elements discourage intentional or inadvertent use of inappropriate filter elements, such as those with unacceptable removal characteristics, pressure drop or service life. The described filter elements either prevent the use of inappropriate filter elements, or at a minimum, hamper the functionality of an installed inappropriate filter element. In the case of filter elements used in fuel applications, this can be achieved when fuel is prevented from flowing when an inappropriate filter element is installed and the engine cannot start. In the case of filter elements used in lubrication oil applications, installation of an inappropriate filter element should not oil starve the engine, so it is desirable that inappropriate filter elements not be able to be installed in the first place. The hole in the combined endplate/lid and/or other elements of the described filter elements provide additional functionality to the filtration system, such as air bleeding, sensor mounting, or other functionality. In addition, by combining the endplate and the lid, the design of the filter element is simplified compared to using separate endplate and lid. 
         [0007]    The filter elements described herein can be used in a number of applications for filtering many types of fluids. Examples of applications include, but are not limited to, filtering of hydrocarbon based fuels such as diesel fuel, lubrication oil, and hydraulic fluid. Therefore, the filter elements can be referred to as fuel filter elements, lubrication oil (or oil) filter elements, hydraulic fluid filter elements, and the like. 
         [0008]    In one embodiment, a filter element includes filtration media arranged into a ring having a first end and a second end and circumscribing a central cavity having a longitudinal axis. A first endplate is sealingly attached to the first end of the filtration media, and a combined endplate/housing lid is sealingly attached to the second end of the filtration media. The combined endplate/housing lid includes a central hole through the combined endplate/housing lid that is in fluid communication with the central cavity and an exterior of the filtration media, a protrusion that projects above a top surface of the combined endplate/housing lid in a direction away from the central cavity and away from the first endplate. The combined endplate/housing also includes a detachable connection mechanism that is used to detachably attach the combined endplate/housing lid to a housing that is configured to receive the filter element. In one embodiment, the central hole extends through the protrusion. 
         [0009]    In another embodiment, a filter assembly includes a filter housing and the filter element is removably disposed in and detachably attached to the filter housing. The filter element can be disposable or reusable. At the end of the service life of the filter element, the filter element can be detached and removed from the filter housing, disposed of (or cleaned), and a new filter element (or the cleaned filter element) installed in the filter housing. 
         [0010]    The central hole in the combined endplate/housing lid can be used for a number of purposes to add or enhance functionality to the filter element. For example, the central hole can be used as an air vent to vent air from the filter assembly. In another example, the central hole can be used to mount one or more sensors, such as a pressure or a temperature sensor. In another example, the central hole mounts a priming indicator to indicate whether the filter is primed. 
     
    
     
       Drawings 
         [0011]      FIG. 1A  illustrates one embodiment of a filter element with combined endplate-lid with internal threads attached to a filter housing. 
           [0012]      FIG. 1B  illustrates another embodiment of a filter element with combined endplate-lid with external threads attached to a filter housing. 
           [0013]      FIG. 2  illustrates the filter element of  FIG. 1B  showing one embodiment of using the central hole in the combined endplate-lid. 
           [0014]      FIG. 3A  illustrates the filter element of  FIG. 1B  interacting with a filter housing standpipe having a sealed end. 
           [0015]      FIG. 3B  illustrates the filter element of  FIG. 1B  interacting with a filter housing standpipe having an air vent opening. 
           [0016]      FIGS. 4A ,  4 B,  5 A, and  5 B illustrate a filter element with combined endplate-lid described herein having a priming visual indicator. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIGS. 1A and 1B  illustrate two exemplary filter elements  10 ,  100  each having a combined endplate/filter housing lid  12 ,  102  with a central hole or opening  14 ,  104 . As shown, the filter elements  10 ,  100  can be removably disposed in and detachably attached to housings  20 ,  120  using a suitable form of detachable connection mechanism to form filter assemblies. In the illustrated examples, the detachable connection mechanism is illustrated as being either internal threads  22  ( FIG. 1A ) or external threads  122  (FIG.  1 B), which engage with corresponding threads on the housings. At the end of the useful life of the filter elements  10 ,  100 , or at any time prior thereto, the filter elements  10 ,  100  can be disconnected and removed from the housings, disposed of, and new filter elements  10 ,  100  installed. Alternatively, in the case of a re-usable filter element, the filter element can be removed, cleaned, and reinstalled. 
         [0018]    In each of  FIGS. 1A and 1B , the housing or module casting  20 ,  120  is illustrated in simplified form without showing the inlet, outlet, etc. Each of the housings  20 ,  120  is generally cylindrical in construction and includes an end wall  40  forming a closed end of the housing, and a side wall  42  extending upwardly from the end wall to an open end  44 . The housings  20 ,  120  can be made from, for example, metal or plastic. 
         [0019]    The filter elements  10 ,  100  are also generally cylindrical in construction and are configured to be removably disposed within the housings  20 ,  120  and removably attached to the housings  20 ,  120 . In the illustrated examples, the threads  22 ,  122  on the combined endplate/lid  12 ,  102  engage with threads formed on the housing  20 ,  120  at the open ends  44  thereof to detachably secure the filter element to the housing. In addition to having threads, both the internal and external thread endplate/lid  12 ,  102  extend beyond the inner diameter of the housing  20 ,  120  to reduce external contamination of the fluid during filter service. Although the use of threads to detachably connect the combined endplate/lid  12 ,  102  and the housings  20 ,  120  has been described, other forms of detachable connection mechanisms between the combined endplate/lid  12 ,  102  and the housings  20 ,  120  can be used, such as ramps or bayonet-style connections or other non-threaded type connections. 
         [0020]    In addition, the endplate/lid  12 ,  102  includes a protrusion  24 ,  124  such as a hexagonal shape nut integrally formed with the endplate/lid  12 ,  102 , to facilitate rotation of the endplate/lid during installation and removal for ease of service. In the illustrated examples, the protrusion  24 ,  124  is located at the center of the endplate/lid surrounding the hole  14 ,  104  (i.e. the hole  14 ,  104  extends through the protrusion  24 ,  124 ) and extends above the upper surface of the endplate/lid in a direction away from the central cavity of the filter element and away from the endplate at the other end of the filter element. However, the protrusion  24 ,  124  (or multiple protrusions) can be located at other locations on the endplate/lid that are accessible by a service technician to rotate the endplate/lid during installation and removal. 
         [0021]    Potential functions for the central hole  14 ,  104  in the combined endplate/lid  12 ,  102  are discussed later. In some embodiments, the hole  14 ,  104  is not centrally located coaxial to the longitudinal axis A-A. Instead, the hole  14 ,  104  can be offset from the axis A-A, yet still opening into and in fluid communication with the central cavity  54 . 
         [0022]    The combined endplate/lid  12 ,  102  is sealed with the housing  20 ,  120  via one or more seals  26 . The seals  26  illustrated in  FIGS. 1A and 1B  are O-rings that form axial seals between the endplate/lid and the sidewall  42  of the housing at the open end  44 . However, other configuration of seals that form other types of seals, including radial seals, can be used. 
         [0023]    The filter elements also include filter media  28 , for example in the form of a ring of filtration media having a first end  50  and a second end  52  and circumscribing a central cavity  54  having a longitudinal axis A-A. Optionally, a perforated center tube  30  supports the interior of the filter media  28  to prevent it from collapsing during outside in flow. In low pressure applications or when the flow of the fluid is inside out, it may not be necessary to use the perforated center tube  30 , as the media may have sufficient strength to avoid collapse in the case of outside in flow. 
         [0024]    A first or bottom endplate  32  is sealingly attached to the first end of the filtration media  28 , for example by using an adhesive or embedding the media  28  into the endplate  32 . In the illustrated embodiment, the endplate  32  includes an opening  34  therethrough so that it is open to fluid flow. It should be noted that for the sake of brevity,  FIGS. 1A ,  1 B and  2  do not show the fluid outlet for the housing nor the manner in which the first endplate  32  seals to the housing. There are multiple ways of doing this, such as the use of axial or radial seals known to those of ordinary skill in the art. However, in some embodiments, the endplate  32  is closed, without the opening  34 , so that the endplate  32  is not open to fluid flow. 
         [0025]    The combined endplate/lid  12 ,  102  is sealingly attached to the second end of the filtration media  28  for example by using an adhesive or embedding the media  28  into the endplate  12 ,  102 . 
         [0026]    The combined endplate/lid  12 ,  102  and the endplate  32  can be formed from the same or different materials. For example, the combined endplate/lid  12 ,  102  and the endplate  32  can each be formed of, for example, metal or plastic material. 
         [0027]    To facilitate the description and for the sake of brevity,  FIGS. 2-4  only show and describe the external thread version of the filter element  100 . However, it is to be understood that the concepts described in  FIGS. 2-4  could be used on the filter element  10 , and on other filter elements, as well. 
         [0028]      FIG. 2  illustrates the central hole  104  being used to house an air vent/bleed mechanism  150  that is connected to and part of the filter element  100 . Cage elements  152  are located at or near the top and bottom of the central hole  104  and include openings  154  therein so that the central cavity  54  of the filter element  100  can be in fluid communication with an exterior of the filter assembly. The cage elements  152 , together with the sides of the endplate  102  that form the central hole  104 , form a cage to retain a ball or other functionally-shaped float  156  within the central hole  104 . The density of the ball  156  is such that while the filter housing is filling with fluid to be filtered, air bleeds from the filter assembly through the air vent/bleed mechanism  150 . When the fluid fills the filter assembly such that it starts to fill the central hole  104 , the ball floats on the fluid and seals in the top opening  154  of the upper cage element  152  to prevent escape of fluid. 
         [0029]    The air vent mechanism described herein is exemplary only, it being understood that other types of air vents are possible. 
         [0030]      FIGS. 3A and 3B  illustrate embodiments in which the central hole  104  is used to seal on an extended standpipe  160 . The standpipe  160  is attached to the housing and is intended to be a permanent part of the housing. The standpipe  160  extends along the longitudinal axis A-A from the end wall  40  toward the open end  44 , and an end of the standpipe  160  extends into the central hole  104 . An o-ring or other radial seal  162  is provided to seal between the standpipe  160  and the endplate/lid  102 , but other sealing means are possible. With this design, any filter element that lacks a central hole of appropriate size and lacks an appropriate sealing mechanism will either leak or be prevented from being installed into the filter housing by the standpipe  160 . Openings  165  in the sides of the standpipe  160  permit fluid to enter the standpipe which leads to an outlet to one or more downstream components that receive the fluid. 
         [0031]    In  FIG. 3A , the standpipe  160  has a closed upper end  164 , so the main function of the hole-standpipe-seal is to ensure that only appropriate filter elements can be installed. In the embodiment shown in  FIG. 3B , an air vent/bleed mechanism  166  is built into the top of the standpipe. In the mechanism  166 , openings  168  are formed in opposing walls of the standpipe  160 , and a floating ball  170  is disposed or caged between the walls and the side wall of the standpipe. So in the embodiment illustrated in  FIG. 3B , the cage and air vent/bleed mechanism  166  is part of the standpipe, but the mechanism  166  is otherwise similar in design and function to the air vent/bleed mechanism  150  in  FIG. 2 , with air to be vented entering the standpipe via the openings  165  during filling of the filter housing by the fluid. In an embodiment, the air vent mechanism is not integral with the standpipe, but is instead separate from the standpipe. 
         [0032]      FIGS. 4A ,  4 B,  5 A and  5 B illustrate an embodiment in which a ball  180  or other float element that is disposed in the central hole (similar to that shown in  FIG. 2 ) is used as a visual indicator to visually indicate if a filter element is primed properly or not.  FIGS. 4A and 4B  show a not fully primed condition where liquid is inside the housing and the filter element, but not completely filling the housing, so that an air gap exists between the liquid and the combined endplate/lid. The ball  180  in the central hole is of higher density than that of air, so the ball sits at the bottom stop of the central hole and is not visible prominently while looking at the combined endplate/lid from above as shown in  FIG. 4B . 
         [0033]    With reference to  FIGS. 5A and 5B , when the housing is completely filled with liquid so the filter assembly is fully primed, the ball  180 , having a lower density than the liquid, floats and seals against the top stop in the central hole. This causes the ball to be prominently visible from the top as best seen in  FIG. 5B  and is then used as a visual indicator to confirm that the housing and filter element are fully and correctly primed. 
         [0034]    Other means to use the central hole to add or enhance functionality to the filter element are also possible. For example, the central hole can be used to mount pressure or temperature sensors. 
         [0035]    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 limitative. 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.