Abstract:
A filter assembly comprises a housing open at one end and holding a filter element therein and a plate closing the open end of the housing and enclosing the filter element within the housing. The plate includes at least two first inlet openings, at least two second inlet openings, and a central outlet opening. The filter assembly further includes a fluid flow controller disposed between an end of the filter element and the plate. The flow controller includes a relief valve comprising a first portion cooperating with the first inlet openings and a second portion cooperating with the second inlet openings; and biasing means operatively connected to the relief valve and providing resistance to movement of the second portion of the relief valve.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/935,633, filed on Feb. 4, 2014, the entire disclosure of which is incorporated herein. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Disclosure 
         [0003]    The present invention relates generally to a fluid filter assembly and, more particularly, to a fluid filter assembly having a fluid flow controller. 
         [0004]    2. Background of the Disclosure 
         [0005]    Filter assemblies generally include a housing having an open end, a filter element received in the housing, an end plate closing the open end and having inlet and outlet openings therein, and a valve for cooperating with the inlet openings to allow oil to flow into the filter through the inlet openings, but prevent flow of oil in a reverse direction. Prior art filters have included a combination valve having two portions, the first portion for closing the inlet openings to block the flow of oil back out of the inlet openings when the oil is not being circulated and the second portion for opening a bypass opening when the filter media is clogged for returning oil to the engine to keep the engine lubricated even though the filter element is clogged. Such a construction is disclosed in Stanhope et al. U.S. Pat. No. 7,175,761. 
         [0006]    The present disclosure improves upon current valves and overcomes disadvantages and deficiencies of such prior art constructions. 
       SUMMARY 
       [0007]    In an illustrative embodiment, a filter assembly may comprise a housing open at one end and holding a filter element therein and an end plate secured to the housing, closing the open end, and enclosing the filter element within the housing, the end plate including a first inlet opening, a second inlet opening, and an outlet opening. The filter assembly further includes a fluid flow controller disposed between an end of the filter element and the end plate. The fluid flow controller includes a relief valve comprising a first portion cooperating with the first inlet opening, a second portion cooperating with the second inlet opening and extending from the first portion, and a spring operatively connected to the relief valve and providing resistance to movement of the second portion of the relief valve. The fluid flow controller is configured to allow fluid flow through only the first inlet opening when a first differential pressure across the first portion of the relief valve is reached and to allow fluid flow through the second inlet opening when a second differential pressure greater than the first differential pressure is reached. 
         [0008]    In any of the embodiments herein, the spring may be at least partially embedded within the relief valve. Further, in any embodiment herein, the spring may include inner and outer rings connected by a plurality of arms, the inner ring may be embedded in a connecting portion between the first and second portions of the relief valve, and the outer ring and the plurality of arms may be embedded within the second portion of the relief valve. Still further, in any of the embodiments herein, each of the plurality of arms may include a first radial segment extending from the inner ring, a second radial segment extending from the outer ring, and an annular segment extending between the first and second radial segments. In any of the embodiments herein, the annular segment may extend through an angle of between about 30 degrees and about 150 degrees. 
         [0009]    In any of the embodiments herein, the spring may include a ring and a plurality of tabs extending inwardly from the ring, the ring may be embedded within the first portion of the relief valve, and the tabs may be embedded within the second portion of the relief valve. 
         [0010]    In any of the embodiments herein, the filter element may include a filter media wrapped around a core and the core includes a projection extending inwardly therefrom. Still further, in any embodiment herein, the second portion of the relief valve may comprise a first segment that covers the second inlet opening, a second segment that abuts at least a portion of the core, and a groove disposed within the first segment of the second portion of the relief valve. The spring may be compressed between the projection and the first segment of the second portion such that a first end of the spring is disposed within the groove, thereby providing resistance to opening of the first segment of the second portion. 
         [0011]    In another illustrative embodiment, a filter assembly may comprise a housing open at one end and holding a filter element therein and a plate closing the open end of the housing and enclosing the filter element within the housing. The plate may include at least two first inlet openings, at least two second inlet openings, and a central outlet opening. The filter assembly may further include a fluid flow controller disposed between an end of the filter element and the plate. The flow controller may include a relief valve comprising a first portion cooperating with the first inlet openings and a second portion cooperating with the second inlet openings; and biasing means operatively connected to the relief valve and providing resistance to movement of the second portion of the relief valve. 
         [0012]    In any of the embodiments herein, the biasing means may be in the form of a spring at least partially embedded within the relief valve. In any of the embodiments herein, the spring may include inner and outer rings connected by a plurality of arms and the outer ring and the plurality of arms may be at least partially embedded within the second portion of the relief valve. Still further, in any of the embodiments herein, each of the plurality of arms may include a first radial segment extending from the inner ring, a second radial segment extending from the outer ring, and an annular segment extending between the first and second radial segments. In any embodiment herein, the annular segment may extend through an angle of between about 30 degrees and about 150 degrees. 
         [0013]    In any of the embodiments herein, the spring may include a ring and a plurality of tabs extending inwardly from the ring and the tabs may be at least partially embedded within the second portion of the relief valve. 
         [0014]    In any of the embodiments herein, the filter element may include a filter media wrapped around a core and the core may include a projection extending inwardly therefrom. Still further, in any embodiment, the second portion of the relief valve may comprise a first segment that covers the second inlet opening, a second segment that abuts at least a portion of the core, and a groove disposed within the first segment of the second portion of the relief valve. The spring may be compressed between the projection and the first segment of the second portion such that a first end of the spring is disposed within the groove, thereby providing resistance to opening of the first segment of the second portion. 
         [0015]    In a further illustrative embodiment, a fluid flow controller for a filter assembly may comprise a relief valve including a first portion and a second portion extending from and connected to the first portion. The fluid flow controller may further include a spring having a ring portion disposed within the first portion and a resilient portion disposed within the second portion, wherein the spring may be configured to require a greater differential pressure to move the second portion of the relief valve than is required to move the first portion. 
         [0016]    In any of the embodiments herein, the spring may include inner and outer rings connected by a plurality of arms, the inner ring may be embedded in a connecting portion between the first and second portions of the relief valve, and the outer ring and the plurality of arms may be embedded within the second portion of the relief valve. Further, in any of the embodiments herein, each of the plurality of arms may include a first radial segment extending from the inner ring, a second radial segment extending from the outer ring, and an annular segment extending between the first and second radial segments, wherein the annular segment may extend through an angle of between about 30 degrees and about 150 degrees. 
         [0017]    In any of the embodiments herein, the spring may include a ring and a plurality of tabs extending inwardly from the ring, the ring may be embedded within the first portion of the relief valve, and the tabs may be embedded within the second portion of the relief valve. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a cross-sectional view of a filter assembly including a cylindrical shell or housing holding a filter element and including a fluid flow controller for controlling flow of fluid into the housing; 
           [0019]      FIG. 2  is an enlarged cross-sectional view of the fluid flow controller of  FIG. 1 ; 
           [0020]      FIG. 3  is a top perspective view of the fluid flow controller of  FIG. 1  including a relief valve with a portion thereof removed to depict a first embodiment of a spring embedded within the relief valve; 
           [0021]      FIG. 4  is a cross-sectional view of the relief valve of  FIG. 1  taken generally along the lines  4 - 4  of  FIG. 3 ; 
           [0022]      FIG. 5  is a top plan view of the spring removed from the relief valve of  FIG. 3 ; 
           [0023]      FIG. 6  is a top perspective view of the fluid flow controller of  FIG. 1  with a portion of the relief valve removed to depict a second embodiment of a spring embedded within the relief valve; 
           [0024]      FIG. 7  is a cross-sectional view of the relief valve taken generally along the lines  7 - 7  of  FIG. 6 ; 
           [0025]      FIG. 8  is a top plan view of the spring removed from the relief valve of  FIG. 6 ; 
           [0026]      FIG. 9  is a cross-sectional view of a filter assembly similar to the filter assembly of  FIG. 1  with a housing thereof removed, wherein the filter assembly includes a fluid flow controller comprising a relief valve and an external spring for controlling flow of fluid into the housing; and 
           [0027]      FIG. 10  is an enlarged cross-sectional view of the fluid flow controller of  FIG. 9 . 
       
    
    
       [0028]    Other aspects and advantages of the present invention will become apparent upon consideration of the following detailed description, wherein similar structures have like or similar reference numerals. 
       DETAILED DESCRIPTION 
       [0029]    The present disclosure is directed to a filter assembly including a fluid flow controller. While the present disclosure may be embodied in many different forms, one specific embodiment is discussed herein with the understanding that the present disclosure is to be considered only as an exemplification of the principles of the disclosure, and it is not intended to limit the disclosure to the embodiment illustrated. 
         [0030]    Referring to  FIGS. 1 and 2 , a filter assembly  20  is depicted as having a generally cup-shaped cylindrical shell or housing  22  that is open at a first or lower open end  24  and closed at a second or upper, opposite end  26 . A filter, for example, in the form of a filter element  28  mounted on a core  30 , is disposed within the housing  22 , wherein the filter element  28  includes a first or lower end  32  positioned adjacent the first end  24  of the housing and a second or upper end  34  adjacent the second end  26  of the housing  22 . While a particular filter is disclosed herein, one skilled in the art will understand that the principles of the present disclosure may be applied to any suitable filter assembly having any suitable filter. An end plate  36  is provided in the lower open end  24  of the housing  22  and may include a lid  38  attached thereto. An annular, resilient gasket (not shown) may be received and retained in a recess  39  in the lid  38  for providing a seal between the filter assembly  20  and an engine block (not shown) to which the filter assembly  20  is secured in normal use. Optionally, any other suitable additional or alternative seal may be used. A biasing element  40 , for example, a spring, may be provided between the upper end  34  of the filter element  28  and an interior  44  of the housing  22  for biasing the filter element  28  toward the first end  24  of the housing  22 . The biasing element  40  may be replaced with any suitable element(s) that bias the filter toward the first end  24  of the housing  22  or may be omitted. 
         [0031]    The filter element  28  may include any suitable filter media comprised of, for example, pleated filter material composed of cellulose with some polyester. The core  30 , which may be molded from any appropriate material, for example, a glass filled plastic, such as, Nylon, is perforated so as to permit fluid flow therethrough in use. The core  30  may comprise a cage formed by vertically disposed members  46  suitably secured to horizontally disposed members  48 , as seen in  FIG. 1 . The filter media may be formed from a sheet of pleated material joined along the facing ends by a suitable adhesive to form an annular sleeve on the core  30 . End caps  50 ,  52  may be disposed at the bottom and top, respectively, of the filter element  28 . The end caps  50 ,  52  may be fabricated from a suitable composite material, for example, a cellulose/polyester composite. In an illustrative embodiment, the end caps  50 ,  52  are bonded to the filter media, for example, by ultrasonic welding, to form a seal between the ends of the filter media and the end caps  50 ,  52  to prevent fluid flow between these elements in use. The end caps  50 ,  52  may alternatively be bonded to the filter media in any other suitable manner. 
         [0032]    The filter element  28  and housing  22  of the filter assembly  20  may be similar to the filter element  28  and housing  22  disclosed in Stanhope et al. U.S. Pat. No. 7,175,761, the disclosure of which is hereby incorporated by reference in its entirety. In other illustrative embodiments, the principles of the present disclosure may be applied to any suitable filter assembly having any suitable housing and/or any suitable filter element. 
         [0033]    Referring to  FIGS. 3-5 , a first embodiment of a fluid flow controller  59  is depicted. The fluid flow controller  59  includes a relief valve  60  retained between the lower end  32  (for example, the end cap  50 ) of the filter element  28  and a top or inner side  62  of the end plate  36 . The relief valve  60  includes a first portion  64  for controlling flow through a first inlet opening or openings  66  in the end plate  36  and a second portion  68  for controlling flow through a second inlet opening or openings  70 , wherein the second portion  68  is connected to the first portion  64  at a connection point  71 . Any suitable number of first inlet openings  66  and/or second inlet openings  70  may be provided. 
         [0034]    An outlet opening  80  is provided centrally within the end plate  36 . As seen in  FIG. 1 , the outlet opening  80  may be centrally disposed about a longitudinal axis  82  of the filter assembly  20 . While the outlet opening  80  is depicted as being circular in cross-section, the outlet opening  80  may have any other suitable configuration depending on the application for the filter assembly  20 . Still optionally, the outlet opening  80  may be oriented in any suitable manner. 
         [0035]    Referring to  FIGS. 3-5 , which show enlarged views of all or portions of the fluid flow controller  59 , the first portion  64  is annular and includes a generally horizontal segment  90  that extends from the connection point  71  and an angled segment  92  extending from the generally horizontal segment  90  and disposed at an angle A 1  with respect to the generally horizontal segment  90 , thereby forming a bend  94  in the first portion  64 . In an illustrative embodiment, the generally horizontal segment  90  extends from the connection point  71  and the angled segment  92  extends at the angle A 1  with respect to a horizontal plane such that a free end  96  of the angled segment  92  is inclined outwardly and downwardly from the generally horizontal segment  90 . The second portion  68  includes an annular inwardly extending segment  98  that is adapted to cooperate with the second inlet openings  70  and an upwardly extending segment  100  that cooperates with the generally horizontal segment  90  of the first portion  64  to form a shoulder  102  that receives a lower end  104  of the core  30  of the filter element  28 . The upwardly extending segment  100  is annular and engages an inner surface  106  of the lower end  104  of the core  30  when assembled. The free end  96  of the angled segment  92  and an end of the inwardly extending segment  98  are bulbous to elevate the first portion  64  and the inwardly extending segment  98  to provide a gap between elastomeric surfaces thereof and the end plate  36  to distribute pressure evening across the relief valve  60 . The relief valve  60  may be made of rubber, plastic, an elastomeric material, or any other suitable material. 
         [0036]    In the illustrative embodiment of  FIGS. 3-5 , a spring  120  may be embedded within the relief valve  60 . The spring  120  is generally planar and is made of a resilient material, such as a thin metal or any other suitable resilient material. Optionally, the spring  120  may be non-planar. As best seen in  FIG. 5 , the spring  120  includes flat inner and outer rings  122 ,  124  connected by a number of flat arms  126 . While three arms  126  are depicted, any number of arms  126  may be utilized to change the resistance of the spring  120 . Each arm includes a first radial segment  128  extending outwardly from the inner ring  122 , a second radial segment  130  extending inwardly from the outer ring  124 , and an annular segment  132  extending between the first and second radial segments  128 ,  130 . In an illustrative embodiment, the annular segment  132  extends through an angle A 2  of about 90 degrees. In other illustrative embodiments, the annular segment  132  may extend through an angle of between about 30 degrees and about 150 degrees. In still alternative illustrative embodiments, the annular segment  132  may extend through an angle of between about 60 degrees and about 120 degrees. While the arms  126  are depicted as including radial segments  128 ,  130  and an annular segment  132 , it is within the scope of the present disclosure to vary the design and shape of the arms  126  and/or include arms of different designs and/or shapes. 
         [0037]    Still referring to  FIG. 5 , elongate openings  140  are formed between the arms  126  and the inner and outer rings  122 ,  124 . Each of the openings  140  includes overlapping inner and outer annular segments  142 ,  144 . In an illustrative embodiment, the inner and outer annular segments  142 ,  144  overlap for an angle A 3  of about 30 degrees, wherein the overlap corresponds to a gap between a first radial segment  128  of one arm  126  and a second radial segment  130  of an adjacent arm  126 . In alternative illustrative embodiments, the inner and outer annular segments  142 ,  144  may overlap for an angle of between about 5 degrees and about 60 degrees. In still further illustrative embodiments, the inner and outer annular segments  142 ,  144  may overlap for an angle of between about 20 degrees and about 45 degrees. 
         [0038]    The spring  120  is at least partially embedded within the relief valve  60 , as seen in  FIGS. 3 and 4 . More particularly, the outer ring  124  of the spring  120  is embedded within the generally horizontal segment  90  of the first portion  64  of the relief valve  60  and the inner ring  122 , the radial segments  128 ,  130 , and the annular segments  132  are embedded within the inwardly extending segment  98  of the second portion  68  of the relief valve  60 . The outer ring  124  anchors the spring  120  within the relief valve  60  and the inner ring  122  and the arms  126  extend into and provide resistance to movement of the inwardly extending portion  98  of the second portion  68  of the relief valve  60 . The resistance of the elastomer of the first portion  64  insures that a pressure necessary to move the first portion  64  and open the first inlet openings  66  is less than a pressure necessary to move the inclined segment of the second portion  68  and open the inlet openings  70 . In an illustrative embodiment, the first portion  64  of the relief valve  60  may open the first inlet openings  66  at a minimum opening pressure, for example, on the order of 1 pound per square inch (psi) and the inwardly extending segment  98  of the second portion  68  may open the second inlet openings  70  at a predetermined higher pressure, for example, on the order of 8-10 psi. The properties of the spring  120  (e.g., the number of arms  126 , the material, the spring rate, tensile strength, hardness, modulus of elasticity, thickness, or any other spring properties) may be varied to vary the pressure necessary to move the inwardly extending segment  98  and open the openings  70 . 
         [0039]    The fluid flow controller  59  may be manufactured in any suitable manner. In one embodiment, the spring  120  may be inserted into a mold and rubber and/or another suitable material may be injected into the mold to create the relief valve  60 . In this manner, when the injected material sets, the spring  120  will be embedded within the relief valve  60 . 
         [0040]    The assembly and operation of the filter assembly  20  and the fluid flow controller  59  will now be described. The filter element  28  is assembled with the annular filter media on the core  30  and the end caps  50 ,  52  secured in place. Assembly of the filter element  28  may occur prior to assembly of the filter assembly  20 , for example, the filter element  28  may be purchased from a third party. The spring  40  or other biasing means, if used, is first inserted into the open end of the housing  12  until it seats against the closed end of the housing  22 . The filter element  28  is positioned in the housing  22  abutting the spring  40 . The fluid flow controller  59  is positioned in the core  30  with the second segment  100  of the second portion  68  of the relief valve  60  engaging the inner surface  106  of the core  30  to help seal fluid flow between the fluid flow controller  59  and the core  30  of the filter element  28 . The end plate  36  is inserted to close the open end of the housing  22  and an outer rim of the lid  38  is rolled, for example, with the open end of the housing  22  to form a seal  141  ( FIG. 1 ). Optionally, any other suitable seal may be formed between the lid  38  and the housing  22 . Positioning of the end plate  36  in the housing  22  partially compresses the spring  40 , whereby, when the parts are assembled, a spring force is applied to the top of the filter element  28  urging the filter element  28  toward the end plate  36 . If the spring  40  is used, the spring force will help to clamp the fluid flow controller  59  between the filter element  28  and the end plate  36  and to seal flow between the filter element  28  and the end plate  36 . The core  30  will firmly engage the upwardly extending segment  100  of the relief valve  60  and will also engage and bear upon the generally horizontal segment  90  of the first portion  64  of the relief valve  60 . 
         [0041]    In operation, the filter assembly  20  is spun onto a stud on the engine block, which engages threads in the central outlet opening  80  in the end plate  36 , and is secured in place. The gasket will engage the engine block and preclude fluid flow between the engine block and the filter assembly  20 . While a particular gasket and lid are described, any suitable gasket and lid configurations may be utilized with the principles of the present application. When the engine is started, fluid, usually oil, will enter the filter assembly  28  through the first inlet openings  66 . Slight pressure will move the first portion  64  of the relief valve  60  away from the first inlet openings  66  and oil will flow through the first inlet openings  66 , the filter media of the filter element  28 , and will be discharged through the central outlet opening  80  for return to the engine. When the engine is turned off, the first portion  64  of the relief valve  60  will close the first inlet openings  66  and prevent return of oil in the filter assembly  20  to the engine. As the filter media clogs during normal operation, differential pressure will build across the inwardly extending segment  98  and, upon attainment of a predetermined pressure, for example, on the order of between about 8 and about 10 psi in an illustrative embodiment, the inwardly extending segment  98  of the second portion  68  of the relief valve  60  will open and permit oil to flow through the second inlet openings  70  and back to the engine, thereby bypassing the filter media of the filter element  28 . In other words, during periods of time when high differential pressure exists across the filter media, due to cold thick oil or high contaminant loading of the filter media, for example, the oil will travel through the second inlet openings  70  and open the inwardly extending segment  98  of the second portion  68  of the relief valve  60  to permit oil to bypass the filter media and exit the filter assembly  20  through the central outlet opening  80  for return to the engine. 
         [0042]    During operation, the spring  120  provides the desired amount of predetermined resistance to moving the inwardly extending segment  98  and opening the second inlet openings  70 . More particularly, the spring  120  is designed with a particular resistance value (based on a spring rate, tensile strength, hardness, modulus of elasticity, thickness, number of arms, distance between arms, and other spring properties), wherein the resistance value is overcome upon attainment of the predetermined pressure in the housing (for example, between about 8 and about 10 psi). The predetermined pressure, and thus the necessary resistance valve of the inwardly extending segment  98  may be different for different filter assemblies and/or applications. The spring  120  is easily customizable for these different applications and provides a more precise resistance value, thereby providing more control over the flow of fluid through the second inlet openings  70 . 
         [0043]    A further embodiment of a fluid flow controller  159  for use with, for example, the filter assembly  20  of  FIGS. 1 and 2 , is depicted in  FIGS. 6-8 . The fluid flow controller  159  includes a relief valve  60  that is identical to the relief valve of  FIGS. 3-5 . The elements of the relief valve  60  will, therefore, not be described in detail and will include the same reference numerals. The fluid flow controller  159  further includes a spring  180  embedded within the relief valve  60 . The spring  180  is generally planar and is made of a resilient material, such as a thin metal or any other suitable resilient material. As best seen in  FIG. 8 , the spring  180  includes a flat ring  182  with a plurality of inwardly extending radial tabs  184 . While eight radial tabs  184  are depicted, any suitable number of radial tabs  184  may be utilized. A central opening  186  is formed by the ring  182  and the radial tabs  184 . An aperture  185  may be disposed in a base of each radial tab  184  adjacent or at a point where the tab  184  is attached to the flat ring  182 . The apertures  185  may be used to vary a spring rate of the tabs  184 . 
         [0044]    The spring  180  is embedded within the relief valve  60 , as seen in  FIGS. 6 and 7 . More particularly, the ring  182  of the spring  180  is embedded within the generally horizontal segment  90  of the first portion  64  of the relief valve  60  and the tabs  184  extend inwardly from the generally horizontal segment  90  into the inwardly extending segment  98  of the second portion  68  of the relief valve  60 . The ring  182  anchors the spring  180  within the relief valve  60  and the tabs  184  extend into and provide resistance to movement of the inwardly extending portion  98  of the second portion  68  of the relief valve  60 . The resistance of the elastomer of the first portion  64  insures that a pressure necessary to move the first portion  64  and open the first inlet openings  66  is less than a pressure necessary to move the inclined segment of the second portion  68  and open the inlet openings  70 . In an illustrative embodiment, the first portion  64  of the relief valve  60  may open the first inlet openings  66  at a minimum opening pressure, for example, on the order of 1 psi and the inwardly extending segment  98  of the second portion  68  may open the second inlet openings  70  at a predetermined higher pressure, for example, on the order of between about 8 and about 10 psi. The properties of the spring  180  (e.g., the number of arms  126 , the material, the spring rate, tensile strength, hardness, modulus of elasticity, thickness, or any other spring properties) may be varied to vary the pressure necessary to move the inwardly extending segment  98  and open the openings  70 . 
         [0045]    The fluid flow controller  159  may be manufactured in any suitable manner. In one embodiment, the spring  180  may be inserted into a mold and rubber and/or another suitable material may be injected into the mold to create the relief valve  60 . In this manner, when the injected material sets, the spring  180  will be embedded within the relief valve  60 . 
         [0046]    The fluid flow controller  159  operates in the same manner as described above with respect to the fluid flow controller  59  of  FIGS. 3-5 . In particular, during operation, the spring  180  provides the desired amount of predetermined resistance to moving the inwardly extending segment  98  of the second portion  68  of the relief valve  60  to open the second inlet openings  70 . More particularly, the spring  180  is designed with a particular resistance value (based on a spring rate, thickness of ring, tensile strength, hardness, modulus of elasticity, number of tabs, thickness of tabs, width of tabs, length of tabs, and other spring properties), wherein the resistance valve is overcome upon attainment of the predetermined pressure in the housing (for example, between about 8 and about 10 psi). The predetermined pressure, and thus the resistance valve of the inwardly extending segment  98  may be different for different filter assemblies and/or applications. The spring  120  is easily customizable for these different applications and provides a more precise resistance value, thereby providing more control over fluid flow through the second inlet openings  70 . 
         [0047]    A further embodiment of a fluid flow controller  259  is depicted in  FIGS. 9 and 10 . The fluid flow controller  259  may be utilized with a filter assembly similar to the filter assembly of  FIGS. 1 and 2 . Only portions of the filter assembly are shown in  FIGS. 9 and 10 , it being understood that omitted portions of the filter assembly may be similar to those described with respect to  FIGS. 1 and 2 . In particular, the filter assembly includes a filter element  262  mounted on a core  264 , both of which are disposed within a housing (not shown) of the filter assembly. The filter element  262  includes a first or lower end  265  and a second or upper end  266 . The filter element  262  and core  264  may be similar to those described with respect to the filter assembly  20  of  FIGS. 1 and 2 . While a particular filter is disclosed herein, one skilled in the art will understand that the principles of the present disclosure may be applied to filter assemblies having any suitable filter. An end plate  268  is provided in an open end of the housing. 
         [0048]    The fluid flow controller  259  includes a relief valve  280  retained between the lower end  265  of the filter element  262  and a top or inner side  282  of the end plate  268 . The relief valve  280  includes a first portion  284  for controlling flow through a first inlet opening or openings  286  in the end plate  268  and a second portion  288  for controlling flow through a second inlet opening or openings  290 , wherein the second portion  288  is connected to the first portion  284  at a connection point  291 . Any suitable number of first inlet openings  286  and/or second inlet openings  290  may be provided. 
         [0049]    As best seen in  FIG. 10 , the first portion  284  of the relief valve  280  is annular and includes a generally horizontal segment  300  that extends from the connection point  291  and an inclined segment  302  extending from the generally horizontal segment  300  and disposed at an angle A 4  with respect to the generally horizontal segment  300 , thereby forming a bend  304  in the first portion  284 . In an illustrative embodiment, the generally horizontal segment  300  extends from the connection point  291  and the inclined segment  302  extends at the angle A 1  with respect to a horizontal plane through the horizontal segment  300  such that a free end  306  of the inclined segment  302  is inclined outwardly and downwardly from the generally horizontal segment  300 . The second portion  288  includes a bulbous annular inwardly extending segment  308  that is adapted to cooperate with the second inlet openings  290  and an upwardly extending segment  310  that cooperates with the first, horizontal segment  300  of the first portion  284  to form a shoulder  312  that receives a lower end  314  of the core  264  of the filter element  262 . The upwardly extending segment  310  is annular and engages an inner surface  316  of the lower end  314  of the core  264  when assembled. An annular groove  320  is disposed in an upper surface of the inwardly extending segment  308  of the second portion  288  of the relief valve  280 . 
         [0050]    The core  264  may comprise a cage formed by vertically disposed members  330  suitably secured to horizontally disposed members  332 , as seen in  FIG. 9 . At least two projections  334  extend inwardly from the core  264 . While discrete projections are shown and described, a single continuous projection or any number of discrete projections may alternatively be used. Each of the projections  334  includes a downwardly-facing (toward the open end of the filter assembly) ledge  336 . The fluid flow controller  259  further includes a spring  340  having a first end  342  disposed within the annular groove  320  in the upper surface of the inwardly extending segment  308  and a second end  344  that abuts and is held in place by the downwardly-facing ledges  336 . In this manner, the spring  340  biases the second portion  288  of the relief valve  280  in a closed position until the resistance of the spring  340  is overcome, thereby allowing fluid flow through the second inlet openings  290 . 
         [0051]    The fluid flow controller  259  operates in the same manner as described above with respect to the fluid flow controller  59  of  FIGS. 3-5 . In particular, during operation, the spring  340  provides the desired amount of predetermined resistance to movement of the inwardly extending segment  308  and opening of the second inlet openings  290 . More particularly, the spring  340  is designed with a particular resistance valve (based on a spring rate, tensile strength, hardness, modulus of elasticity, thickness, and other spring properties), wherein the resistance valve is overcome upon attainment of the predetermined pressure in the housing (for example, between about 8 and about 10 psi). The predetermined pressure, and thus the resistance valve of the inwardly extending segment  308  may be different for different filter assemblies and/or applications. The spring  120  is easily customizable for these different applications and provides a more precise resistance value, thereby providing more control over fluid flow through the second inlet openings  290 . 
         [0052]    In any of the embodiments herein, a resistance or load on the spring when assembled in the filter may be determined by multiplying a surface area of the relief valve that is exposed to a differential pressure across it times a predetermined relief valve opening pressure. For example, if an area under the spring is approximately 1 square inch and a predetermined valve opening pressure is 20 pounds per square inch (psi), the spring load would be 20 pounds. 
         [0053]    While directional terminology, such as upper, lower, top, bottom, etc. is used throughout the present application, such terminology is not intended to limit the disclosure. Such terminology is only used for purposes of describing the various features and components in relation to one another. While certain illustrative embodiments have been described in detail in the figures and the foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, systems, and methods described herein. It will be noted that alternative embodiments of the apparatus, systems, and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the apparatus, systems, and methods that incorporate one or more of the features of the present disclosure.