Abstract:
A filter cartridge has first and second housing sections joined at a peripheral shoulder to define an interior space. The first housing section includes radially spaced inner and outer side walls connected by a first transition portion to define an annular space. A lock ring is secured to the housing within the annular space. The lock ring includes at least one engagement structure within the annular space.

Description:
BACKGROUND OF THE DISCLOSURE 
       [0001]    The present disclosure relates to filters, and more particularly, to a filter cartridge for use in a fuel supply system. 
         [0002]    Significant quantities of contaminants such as water and assorted abrasive particles may be found in fuel. To remove contaminants and prevent damage to sensitive engine components, fuel supply systems may include one or more filter assemblies configured to remove water and contaminants from the fuel supply. Filter assemblies may include a removable filter cartridge or other element defining a fuel flow path through one or more filter media to remove particulates and separate water from fuel before the fuel is delivered to sensitive engine systems. The filter cartridge or element is configured such that the filter cartridge may be replaced according to maintenance schedules or as needed. 
         [0003]    In practice, fuel filtration requirements may vary depending upon: the type and make of the internal combustion engine; the specific application for which the engine is employed; the climate in which the engine operates; and/or regional characteristics as to the quality of the fuel supply. Replaceable filtration components suitable for use in a particular filtration system commonly vary as to capacity, fluid compatibility, water separation, and filtration efficiency. 
         [0004]    Traditional fuel filters may utilize any of a variety of configurations to retain a filter cartridge to a filter head. The filter cartridge and filter head may be mated directly at an external diameter of the filter cartridge. Alternatively, the filter cartridge can be secured to the filter head by an external ring surrounding the outside diameter of the filter cartridge. 
         [0005]    Connections between a filter cartridge and filter head are required to withstand vibration, shock, and relatively high internal pressure, while accommodating an increasing volume of fuel and cyclical pressure changes which typify modern fuel supply systems. 
         [0006]    One of the recurring problems in assuring filtration system performance is encountered in the connection of the filter cartridge to the filter head. It is imperative that the replacement cartridge be compatible with the filtration requirements of the fuel system. Some replacement cartridges are configured to engage the filter head at an outermost diameter. The cartridge is either directly connected to the filter head or indirectly connected to the filter head by a separate ring sliding over the outermost diameter of the cartridge. This kind of peripheral engagement may radially limit the diameter of replacement cartridges, which can limit the size and resulting filtration capacity of the filter media contained within. 
         [0007]    There is a need in the art for a filter cartridge that is not radially constrained by the engagement with the filter head and is usable with a variety of previously designed filter heads. 
       SUMMARY 
       [0008]    One embodiment of the disclosed filter cartridge comprises a lock ring incorporated into a filter cartridge configured to accept a mating annular portion of a filter head. 
         [0009]    Filter assemblies include a filter head which defines a receptacle for receiving the communication end of a filter cartridge and may include an engagement structure for retaining a received cartridge. When properly received in a filter head, the communication end of a filter cartridge receives the fuel inlet/outlet conduits projecting from the head. Fuel is directed through filter media contained within the cartridge and clean fuel is passed on to the engine. 
         [0010]    The present disclosure is directed to a filter cartridge incorporating inwardly directed engagement features that may be in the form of a lock ring. One preferred form of the lock ring is mounted within an annular space at the communication end of the filter cartridge by an interference fit. The annular space includes at least one engagement structure that communicates with the head portion. In another embodiment of the disclosed filter cartridge, the lock ring is mechanically crimped along its outer edge to an interior edge of the filter cartridge. The lock ring may engage the filter head by a threaded or bayonet connection system or the like. 
         [0011]    An object of the disclosure is to provide a new and improved connection system for a filter cartridge which provides for the efficient connection to a filter head where the radius of the cartridge is not limited by the connection system. Other objects and advantages of the disclosure will become apparent from the specification and the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present disclosure may be better understood and its numerous objects and advantages will become apparent to those skilled in the art by reference to the accompanying drawings in which: 
           [0013]      FIG. 1  is a longitudinal sectional view of a first embodiment of a filter cartridge incorporating a lock ring in accordance with the present disclosure; 
           [0014]      FIG. 2  is an enlarged view of the connection between the filter cartridge and lock ring of  FIG. 1 ; 
           [0015]      FIG. 3  is an exploded sectional perspective view of a filter assembly including a filter head and a filter cartridge that incorporates a lock ring system in accordance with the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    With reference to the drawings wherein like numerals represent similar parts throughout the several figures, a filter cartridge  10  incorporates a lock ring  12  in accordance with the present disclosure. 
         [0017]      FIG. 1  is a sectional view through a filter cartridge  10  and a lock ring  12 . The filter cartridge comprises a first housing section  14  joined to a second housing section  16  along a peripheral edge  18  to form an interior space  66 . The interior space  66  contains a filter element  20  that is supported within the filter cartridge  10 . Upper grommet  22  surrounds the fuel inlet port  24  and lower grommet  40  surround the fuel outlet port  42  about longitudinal axis A-A of the filter cartridge. First housing section  14  and upper end cap  48  receive coaxial conduits  51 ,  52  (see  FIG. 3 ) for delivery of unfiltered fluid and retrieval of filtered fluid from the filter cartridge  10 . 
         [0018]      FIG. 2  illustrates an enlarged view of the connection between filter cartridge  10  and lock ring  12 . The first housing section  14  includes outer side wall  26 , first transition portion  28 , inner side wall  30 , and second transition portion  32 . The outer side wall  26 , first transition portion  28 , and inner side wall  30  form an annular space  19  in the filter cartridge to allow for reception of the lock ring  12  interior the peripheral edge  18 . In the depicted embodiment, the first transition portion  28  is defined essentially by a radius R 2 , subtending an obtuse angle and rotated about a point within the annular space  19 . The first transition portion  28  is rotated about the longitudinal axis A-A to define a concave three-dimensional torus. In the depicted embodiment, the second transition portion  32  is defined essentially by a radius R 1 , subtending an obtuse angle and rotated about a point within the interior space  66 . The second transition portion  32  is rotated about the longitudinal axis A-A to define a convex three-dimensional torus. The depicted embodiment allows the first housing section  14  to be constructed from a single contiguous sheet of material. 
         [0019]    In one embodiment, depicted in  FIG. 1 , the width X of the annular space  19  is approximately 10% the diameter of the cartridge D 1 . A wider annular space  19  would result in less interior space  66  but may be necessary depending on the filter head. The aforementioned annular space  19  allows the lock ring  12  to engage the filter head  38  interior the peripheral edge  18  of second housing section  16 . The engagement within annular space  19  allows the filter cartridge  10  to extend beyond the peripheral edge  18  in the radial direction. 
         [0020]    Referring to  FIG. 1 , the height of the first housing section  14  relative to the height of the cartridge  10  may differ. In one embodiment, the first housing section first height Y 1  is approximately equal to the first housing section third height Y 3 . In another embodiment, the first housing section first height Y 1  is approximately 90% of the first housing section third height Y 3 . In another embodiment, the first height of the first housing section Y 1  may be approximately 20% of the height of the filter cartridge Y 2 . 
         [0021]    In an embodiment most clearly depicted in  FIG. 3 , the lock ring  12  preferably has an inner surface  34  and outer surface  36 . The inner surface  34  is configured to engage a complementary annular portion of the filter head  38 . The filter head  38  has an annular, downwardly projecting skirt  71  that includes outwardly projecting engagement structures  70 . The inner surface  34  of lock ring  12  includes inwardly projecting engagement structures  68  complementary to the outwardly projecting engagement structures  70 . These complementary engagement structures are configured such that the lock ring  12  engages the filter head  38  when the cartridge is rotated a first direction and disengages when the cartridge is rotated in a second direction opposite the first direction. These complementary engagement structures may comprise a threaded or bayonet connector system or the like. The skirt  71  has a configuration complementary to the annular space  19  in the filter cartridge  10  to allow for reception of the skirt  71  interior the peripheral edge  18 . 
         [0022]    Referring to  FIG. 1 , a continuous ring of filter media  44  extends between first (upper) and second (lower) end caps ( 48  and  50  respectively) of the filter element  20 . The filter media  44  may be constructed of cellulose paper or any other permeable fibrous material. As shown in  FIGS. 1 and 2 , the upper end cap  48  mechanically connects the filter element  20  to the filter cartridge  10 . The upper end cap  48  surrounds the fuel outlet port  42  around the longitudinal axis A-A. The fuel outlet port  42  is configured as a receptacle to receive a fuel outlet conduit  52  depicted in  FIG. 3 , thus allowing filtered fuel to exit the filter cartridge  10 . 
         [0023]    As depicted in  FIGS. 1 and 2 , filter element retention arms  54  project axially from the upper end cap  48  at the perimeter of the fuel outlet port  42  and retain the first housing section  14  at annular lip  60 . The set of filter element retention arms  54  surround the fuel outlet port  42  in a circle coaxial with the longitudinal axis A-A of the filter cartridge. Depending on the pressure within the filtration environment, the characteristics of the filter element retention arms  54  may be adapted to ensure a more secure connection. As one of skill in the art will appreciate, increasing the width of the arms  54 , increasing the thickness of the arms  54 , or multiplying the number of arms  54  will increase the retention force the arms can exert on the annular lip  60 . 
         [0024]    Filter element retention barbs  56  project radially inward from the terminal end of the filter element retention arms  54 . In the embodiment illustrated in  FIG. 2 , the barbs have an engagement ramp  58  oriented towards the annular lip  60  of the first housing section  14 . Proceeding from the terminal end of the arms  54  and moving towards the upper end cap  48 , the barbs  56  increase in width while traveling along the engagement ramp  58 . At the end of the engagement ramp  58  nearest the upper end cap  48  the barbs  56  terminate in a retention ledge  62 . The ledge  62  shown in the figures is a flat surface that projects radially from a surface of the arms  54  towards axis A-A adjacent the engagement ramp  58 . Like the arms  54 , the characteristics of the ledge  62  and the annular lip  60  of the filter cartridge  10  may be altered to provide a more secure connection to the cartridge  10 . For example, increasing the length of the ledge  62  and the radial width of the annular lip  60  will increase the retention forces exerted by the barbs  56  on the annular lip  60 . 
         [0025]    In one embodiment, the barbs  56  may be located on the surface of the retention arms  54  oriented towards a longitudinal axis A-A of filter cartridge  10 . Thus, in the configuration of  FIGS. 1-3 , the ledge  62  projects radially toward the longitudinal axis A-A of filter cartridge  10 . In an alternate embodiment, the barbs  56  are located on the surface of the arms  54  oriented away from longitudinal axis of the cartridge A-A (not shown). 
         [0026]    As shown in  FIGS. 1 and 2 , a plurality of support ribs  64  extend radially from the filter element retention arms  54 . The support ribs  64  are connected to a surface of the arms  54  facing away from the fuel outlet port  42  and provide biasing forces to aid in retention of the filter element  20  within the filter cartridge  10 . In the embodiment illustrated in  FIGS. 1 and 2 , the support ribs exert forces stiffens the arms. Furthermore, in one embodiment where the ribs  64  extend from the arms  54  to a perimeter of the upper end cap  48 , the ribs  64  ensure that the upper end cap  48  is centered within the first housing section  14 . By extending beyond the perimeter of the upper end cap  48 , the ribs  64  abut the first housing section  14  when installed, which may prevent the upper end cap  48  from moving from side to side within the filter cartridge housing  10 . 
         [0027]    In one embodiment, the ribs  64  also act to define a plurality of fuel flow pathways. For example, in  FIG. 1  the ribs  64  extend past the periphery of upper end cap  48  and abut the inside surface of the first housing section  14 . At the periphery, the ribs  64  are axially raised from the upper end cap  48 , creating a gap between the upper end cap  48  and the first housing section  14  of the filter cartridge. The ribs  64  define fuel flow paths extending radially outwardly across the upper end cap  48 . 
         [0028]    Fluid flow through the filter cartridge  10  will now be described, where the fuel flow is indicated with arrows. In the embodiment of the filter cartridge depicted in  FIGS. 1 and 3 , unfiltered fuel enters the cartridge from the head  38  through fuel inlet port  24 . Conduits  51  and  52  are received in grommets  22  and  40 , respectively, to define separate flow paths for fuel entering the cartridge and clean fuel leaving the cartridge. Fuel flows radially across the upper end cap  48  through gaps in the filter element retention arms  54 , and around the periphery of the upper end cap  48 . After flowing around the periphery, fuel flows radially inwardly through the filter media  44 , and axially toward the fuel outlet conduit  52 . Fuel then flows through fuel outlet port  42  and exits the head  38 .