Patent Publication Number: US-2007114170-A1

Title: Fuel filter cartridge apparatus

Description:
FIELD OF THE INVENTION  
      This invention relates generally to devices for filtering and separating fluids. More particularly, the invention relates to fuel filters for removing foreign particles and separating water from fuel and fuel supply systems of a engine.  
     BACKGROUND OF THE INVENTION  
      In order to ensure proper operation, and long life of an engine, it is known in the art to provide a fuel filter having an element that is capable of removing particulate matter and water from the fuel being supplied to the engine. Generally, such fuel filters include a disposable filter cartridge which is detachably mounted to a base, so that the filter cartridge can be replaced at periodic intervals. The base and fuel cartridge are cooperatively configured in such a manner that the base directs fluid into and out of the cartridge.  
      Filter cartridges, of the type used for filtering fuel being supplied to an engine, typically include a filter pack, also sometimes referred to as a filter element, mounted within a filter housing disposed about the filter pack, with a lower end of the housing defining a fluid sump extending substantially below the filter pack at the lower end of the housing. The mounting base and cartridge are configured in such a manner that fuel entering the filter is directed around the outside of the filter element, and such that the filtered and de-watered fuel is removed from the interior of the filter element. The filter element is constructed in such a manner that water coalesces on the outside of the filter element, and is directed into the sump of the housing by the force of gravity.  
      In order to allow periodic draining of the separated water from the sump, the filter housing also typically includes a drain fitting passing through the housing in the sump region, and attached to the housing. Such drain fittings are typically configured for threaded attachment thereto of a drain cock which allows the drain fitting to be selectively sealed or opened for draining water out of the housing of the filter cartridge.  
      In some filters, the drain fitting is further adapted for attachment thereto of a drain bowl providing an additional sump area for receiving water. Such drain bowls are sometimes fabricated of transparent or translucent materials allowing a visible indication from outside the filter of how much water is present within the drain bowl. The drain bowl also typically includes a drain bowl drain cock which allows selective draining of the water in the drain bowl, at periodic intervals. U.S. Pat. No. 5,236,579 to Janik et al. discloses a fuel filter assembly with modular drain bowl, of the type generally described above.  
      Because the filter cartridge is a throw-away item, it is highly desirable that the cartridge be configured in a manner conducive to automated assembly at a low cost. The manner in which a drain fitting is attached to the housing in such filters can significantly impact the manufacturability and overall costs of the filter cartridge.  
      In some prior filter cartridges, including the cartridge disclosed in the Janik &#39;579 patent, the drain fitting is press-fitted into a protrusion extending from a lower end of the cartridge housing. In order to ensure that an adequate connection is formed between the drain fitting and the housing, where the drain fitting is press-fitted into the housing, it is necessary that an outer peripheral portion of the drain fitting, and a mating inside surface of the housing, be accurately controlled to close tolerances. The necessity for maintaining such close tolerances on the drain fitting and housing tends to drive up manufacturing cost and difficulty.  
      Experience has also shown, that where a drain fitting is simply pressed into a housing, the drain fitting may loosen over time, and rotate with the drain cock, or other bolted attachments to the drain fitting, in such a manner that it is not possible to drain the contents from the sump of the filter. It is also noted that, should the drain fitting become loose, in prior filter cartridges having the drain fitting merely pressed into the housing, the drain fitting may be pulled out of, or pushed into the interior of, the housing during operation of a drain cock or other threaded fastener attaching a fluid bowl to the filter cartridge.  
      It is desirable, therefore, to provide an improved filter cartridge, and a method for manufacturing a filter cartridge, which overcome one or more of the problems described above. It is further desirable that such an improved filter cartridge be adaptable for use with existing filter bases, and allowing use of the filter cartridge with either a typical drain cock, and/or a fluid bowl.  
     BRIEF SUMMARY OF THE INVENTION  
      The invention provides an improved fluid filter cartridge, and method for manufacturing such an improved fluid filter cartridge, by utilizing a crimped connection for attaching a drain fitting to a housing of the filter cartridge. Practice of the invention allows the drain fitting to be loosely fitted into the housing, prior to forming the crimped connection, thereby eliminating the additional complexity and cost associated with the press-fitted attachment of drain fitting to housings in prior filter cartridges, and providing a more secure joint to be formed between the drain fitting and housing than could be achieved in prior filter cartridges.  
      In one form of the invention, a filter cartridge includes a filter pack, and a housing disposed about the filter pack. The housing defines an upper and a lower end thereof, and a sump extending substantially below the filter pack at the lower end of the housing. The housing further includes a drain fitting passing through the housing in the sump and attached to the housing. The drain fitting has an outer periphery thereof which includes a crimping recess therein, and the housing includes a crimped portion thereof which is formed into the crimping recess of the drain fitting, to thereby form a crimped connection between the drain fitting and the housing.  
      The crimping recess may also include at least one anti-rotation feature, around which the crimped portion of the housing is formed for resisting rotation of the drain fitting with respect to the housing. Where the drain fitting defines an axis of passage through the housing, the crimping recess in the drain fitting may be a radially outwardly opening groove. An anti-rotation element, in the form of a raised rib, may extend outwardly from and substantially axially across the crimping recess.  
      The housing of a filter cartridge according to the invention, may include a tubular wall section thereof, disposed about the periphery of the drain fitting and including the crimped portion of the housing. A housing, according to the invention, may also have a cup-shaped extension thereof including the tubular wall, and having an axially facing end wall thereof joined to the tubular wall, with the end wall having a hole therein providing fluid communication with openings in the drain fitting. The drain fitting may be configured for operative attachment thereto of a drain cock, and the end wall of the cup-shaped extension may define a sealing surface thereof, adapted for cooperatively forming a sealable juncture with the drain cock, to thereby allow for selectively opening or closing-off fluid communication through the drain fitting.  
      A filter cartridge apparatus, according to the invention, may include either or both of, a filter pack disposed within the filter housing, and a sealing element operatively attached to the drain fitting, such as a drain cock and/or a drain bowl.  
      A method, according to the invention, for constructing a fluid cartridge having a drain fitting attached to a housing with a crimped connection, may include configuring the housing to have a crimpable portion thereof for attachment to the drain fitting, and loosely inserting the drain fitting into the crimpable portion before forming the crimped connection. A method, according to the invention, may also include configuring an outer peripheral surface of the drain fitting to have a crimping groove, and forming the crimpable portion of the housing into the crimping groove of the drain fitting to thereby form the crimped connection between the housing and the drain fitting.  
      A method, according to the invention, may further include configuring the housing of a fluid filter cartridge according to the invention to include a tubular wall section thereof, disposed about the periphery of the drain fitting and including the crimpable portion of the housing. A method may further include configuring the housing to provide a cup-shaped extension thereof, with the cup-shaped extension including the tubular wall and having an axially facing end wall of the cup-shaped extension joined to the tubular wall, with the end wall having a hole therein for providing fluid communication with the drain fitting. A method, according to the invention, may yet further include configuring the end wall of the cup-shaped extension to define a sealing surface thereof, for cooperatively forming a sealable juncture with a sealing element, to thereby selectively open or close-off fluid communication through the drain fitting.  
      A sealing element, in accordance with the invention, may take a variety of forms, including a resilient seal member, a drain cock, and/or a drain bowl.  
      Other aspects, objectives and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:  
       FIG. 1  is a vertical cross-section taken through a filter apparatus including an exemplary embodiment of a fluid filter cartridge, in accordance with the invention;  
       FIG. 2  is a partially cut-away perspective illustration of the drain fitting of the exemplary embodiment of the filter cartridge shown in  FIG. 1 ;  
       FIG. 3  is a partially cut-away perspective illustration showing a crimped connection between the housing and the drain fitting of the exemplary embodiment of the filter cartridge shown in  FIG. 1 .  
       FIG. 4  is an enlarged partial cross-section of a sump area of the filter cartridge of the exemplary embodiment of the filter cartridge shown in  FIG. 1 , illustrating attachment of a drain cock to the drain fitting of the exemplary embodiment;  
       FIG. 5  is an enlarged partial cross-section of a sump area of the filter cartridge of the exemplary embodiment shown in  FIG. 1 , illustrating the manner in which a drain bowl is attached to the drain fitting of the exemplary embodiment of the filter cartridge; 
    
    
      While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.  
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  shows an exemplary embodiment of the invention in the form of a filter cartridge apparatus  10 , which is adapted for operative connection to a mounting base  12  by a retaining collar  14 . In the exemplary embodiment, the filter cartridge  10  includes an integrally formed peripheral ridge  16 , against which the retaining collar  14  bears, as the retaining collar  14  is screwed into place on the base  12 , for forming an operative attachment between the filter cartridge  10  and the base  12 . Those having skill in the art will recognize, however, that in other embodiments of a filter cartridge, according to the invention, the filter cartridge  10  may be attached to a mounting base in a variety of other ways.  
      The filter cartridge  10  includes a filter pack  18 , and a housing  20  disposed about the filter pack  18 . The housing  20  has an upper end  22  and a lower end  24  thereof, with the lower end  24  of the housing defining a sump  26  extending substantially below the filter pack  18  at the lower end  24  of the housing  20 .  
      The housing  20  further includes a drain fitting  28  passing through the housing  20  in the sump  26 , and attached to the housing  20  with a crimped connection  30 , in a manner described in more detail below. The drain fitting  28  defines an axis of passage  32 , through the housing  20 . In the exemplary embodiment of the filter cartridge  10 , the axis of passage  32  of the drain fitting  28  is substantially coincident with a central axis of the filter cartridge  10 , but in other embodiments of the invention, the axis of passage need not necessarily be coincident with such a central axis of a filter cartridge according to the invention.  
      As shown in  FIG. 2 , the drain fitting  28 , of the exemplary embodiment of the invention, has an outer periphery thereof including a crimping recess  34  therein, in the form of a radially outwardly opening groove. The crimping recess  34 , of the exemplary embodiment, also includes a plurality of anti-rotation features, in the form of raised ribs  36  extending outwardly within and substantially axially across the crimping recess  34 .  
      As shown in  FIG. 3 , the housing  20  includes a crimped portion  38  thereof, which is formed into the crimping recess  34 , of the drain fitting  28 , to thereby form the crimped connection  30  between the drain fitting  28  and the housing  20 . As shown at  40 , in  FIG. 3 , the crimped portion  38  of the housing  20  is also formed about the raised ribs  36  of the drain fitting  28  for restraining the drain fitting  28  against rotation with respect to the housing  20 .  
      As further shown in  FIG. 3 , the housing  20 , of the exemplary embodiment, includes a cup-shaped extension  42  including a tubular wall  44  and an axially facing end wall  46  thereof joined to the tubular wall  44  of the cup-shaped extension  42 . The tubular wall section  44 , of the cup-shaped extension  42 , is disposed about the periphery of the drain fitting  28 , and includes the crimped portion  38  of the housing  20 . The end wall  46 , of the cup-shaped extension  42 , includes a hole  48  which is aligned with the drain fitting  28  and provides fluid communication with openings  50  extending through the drain fitting  28 , for draining fluid from the interior of the filter cartridge  10 . It will be appreciated that the cup-shaped extension  42  serves as a self-fixturing feature to properly position the drain fitting  28  axially and radially, with respect to the crimpable portion  38  of the housing  20 , to thereby streamline construction and reduce cost.  
      As shown in  FIG. 2 , the drain fitting  28 , of the exemplary embodiment includes a central female-threaded hub  52 , joined to an outer rim  54  by a plurality of struts  56 , with open spaces between the hub  52 , outer rim  54 , and struts  56  forming the openings  50  for passage of fluid through the drain fitting  28 . It will be appreciated, however, that in alternate embodiments of the invention, a drain fitting may have a configuration differing substantially from the configuration of the drain fitting  28  of the exemplary embodiment described herein.  
      As shown in  FIG. 4 , by virtue of the configuration of the end wall  46  of the tubular wall portion  44  of the housing  20 , of the exemplary embodiment of the filter cartridge  10 , a resilient sealing member  60  of a sealing element, such as the drain cock  62  shown in  FIG. 4 , may cooperatively form a sealable juncture with the sealing element  62 , to thereby allow for selectively opening or closing-off fluid communication through the drain fitting  28 .  
      As shown in  FIG. 5 , the exemplary embodiment of the filter cartridge  10  is further configured in such a manner that a sealing element in the form of a drain bowl  64  may be operatively attached to the drain fitting  28  by a through-bolt  66 . The drain bowl  64 , shown in  FIG. 5 , includes a drain cock  62  and a resilient seal member  60  for draining fluid from the drain bowl  64 . The configuration of the exemplary embodiment of the filter cartridge  10  allows for seals between the drain bowl  64  and housing  20  of the filter cartridge  10  to be placed around the cup-shaped extension  44 , as indicated by O-ring seal  68 , or alternatively by a face seal  70  bearing against the end wall  46  of the cup-shaped portion  42  of the housing  20 .  
      It will be appreciated, by those having skill in the art, that, by virtue of the various features and elements of the exemplary embodiment described above, the crimped connection  30  allows far greater flexibility, and openness of manufacturing tolerances, than could be tolerated by prior filter cartridges in which a drain fitting was press-fitted into a housing. In a filter cartridge, according to the invention, the periphery of the drain fitting need not fit tightly into the housing in making the crimped joint. Furthermore, in embodiments of the invention utilizing anti-rotation features, and a substantially radially outwardly opening crimping groove, as described above in relation to the exemplary embodiment, a filter cartridge, according to the invention, provides far greater resistance to having the drain fitting pushed back into the interior of the housing, or rotating with respect to the housing, than can be achieved by prior filter cartridges in which a drain fitting is merely press-fitted into the housing.  
      The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.  
      Preferred embodiments of this invention are described herein, including the best mode known to the inventor for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventor intends for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.