Abstract:
A filter assembly comprises a housing open at a first end and holding a filter element therein and an end plate secured to the housing and closing the first end and enclosing the filter element within the housing. The plate includes 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 flow controller includes a valve including a first portion cooperating with the first inlet opening and a second portion cooperating with the second inlet opening. The fluid flow controller further includes a spring-loaded valve seat in communication with the valve and providing resistance to movement of the first portion of the valve.

Description:
CROSS-REFERENCE 
     This application claims the benefit of U.S. Provisional Patent Application No. 61/945,653, filed on Feb. 27, 2014, and entitled “FLUID FLOW CONTROLLER AND FILTER ASSEMBLY WITH FLUID FLOW CONTROLLER”, the entire disclosure of which is incorporated herein. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates generally to a fluid filter assembly and, more particularly, to a fluid filter assembly having a fluid flow controller. 
     2. Background of the Disclosure 
     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. 
     The present disclosure improves upon current valves and overcomes disadvantages and deficiencies of such prior art constructions. 
     SUMMARY 
     In an illustrative embodiment, a filter assembly may including a housing open at a first end and holding a filter element therein and an end plate secured to the housing and closing the first 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 may further include a fluid flow controller disposed between an end of the filter element and the end plate, the fluid flow controller comprising a valve including a first portion cooperating with the first inlet opening and a second portion cooperating with the second inlet opening. The fluid flow controller may further include a spring-loaded valve seat in communication with the valve and providing resistance to movement of the first portion of the valve. 
     In any of the embodiments herein, the fluid flow controller may be adapted to allow fluid flow through the first inlet opening when a first differential pressure across the first portion of the valve is reached and to allow fluid flow through the second inlet opening when a second differential pressure that is less than the first differential pressure across the first portion of the valve is reached. 
     In any of the embodiments herein, the valve seat may be positioned adjacent the first portion of the valve and may be movably positioned within a stationary valve housing. In any embodiments herein, an annular flange may extend outwardly from the valve housing and may be positioned between the filter element and the valve to retain the valve housing in position and prevent movement of the valve housing. 
     In any of the embodiments herein, the valve seat may include an outer wall with a plurality of projections that extend from the outer wall into a plurality of slots disposed within an outer wall of the valve housing. In any of the embodiments herein, the valve seat may include an inner wall with a second plurality of projections that extend from the inner wall into a second plurality of slots disposed within an inner wall of the valve housing. In any of the embodiments herein, the plurality of slots within the outer wall may be offset with respect to the second plurality of slots within the inner wall and the plurality of projections within the outer wall may be offset with respect to the second plurality of slots within the inner wall. 
     In any of the embodiments herein, the valve seat and the valve housing may include U-shaped bodies that form a continuous cavity in which a spring is disposed. In any of the embodiments herein, the spring may bias the valve seat against the first portion of the valve and, when a predetermined differential pressure across the first portion of the valve is reached, the valve seat is pushed against the bias of the spring into the valve housing to open the first inlet opening. 
     In any of the embodiments herein, at least one projection may extend from a surface of the first portion of the valve toward the end plate to provide spacing between the first portion of the valve and the end plate. 
     In another illustrative embodiment, a fluid flow controller for a filter assembly may include a check valve including a first portion and a second portion extending from and connected to the first portion and a spring-biased valve seat disposed adjacent the first portion of the check valve. The spring-loaded valve seat may prevent opening of the first portion of the check valve below a predetermined pressure and a pressure required to move the second portion of the check valve may be less than the predetermined pressure required to move the first portion of the check valve. 
     In any of the embodiments herein, the valve seat may be positioned adjacent the first portion of the valve and may be movably positioned within a stationary valve housing. 
     In any of the embodiments herein, the valve seat may include an outer wall with a plurality of projections that extend from the outer wall into a plurality of slots disposed within an outer wall of the valve housing. In any of the embodiments herein, the valve seat may include an inner wall with a second plurality of projections that extend from the inner wall into a second plurality of slots disposed within an inner wall of the valve housing. In any of the embodiments herein, the plurality of slots within the outer wall may be offset with respect to the second plurality of slots within the inner wall and the plurality of projections within the outer wall may be offset with respect to the second plurality of slots within the inner wall. 
     In any of the embodiments herein, the valve seat and the valve housing may include U-shaped bodies that form a continuous cavity in which a spring is disposed. In any of the embodiments herein, the spring may bias the valve seat against the first portion of the valve and, when a predetermined differential pressure across the first portion of the valve is reached, the valve seat may be pushed against the bias of the spring into the valve housing to open the first inlet opening. 
     In another illustrative embodiment, a method of controlling fluid flow into a filter assembly including a housing open at a first end and holding a filter element therein, an end plate secured to the housing and closing the first 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, and a fluid flow controller disposed between an end of the filter element and the end plate, the fluid flow controller comprising a valve including a first portion cooperating with the first inlet opening and a second portion cooperating with the second inlet opening, and a spring-loaded valve seat in communication with the valve and providing resistance to movement of the first portion of the valve may comprise the step of allowing fluid flow into the filter assembly through only the second inlet opening when a first differential pressure across the valve is reached. The method may further comprise the step of forcing the spring-loaded valve seat away from the first portion of the valve when a second differential pressure greater than the first differential pressure across the valve is reached, thereby allowing fluid flow through the first inlet opening. 
     In any of the embodiments herein, the method may further include the step of forcing the sprong-loaded valve seat into a valve housing against the bias of a spring. 
     In any of the embodiments herein, the method may further include the step of providing a plurality of projections extending from the spring-loaded valve seat that slidingly engage a plurality of slots within the valve housing to allow longitudinal movement of the spring-loaded valve seat within the valve housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         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, wherein the fluid flow controller generally includes a check valve, a valve seat, and a valve housing; 
         FIG. 2  is an enlarged cross-sectional view of the check valve of the fluid flow controller of  FIG. 1 ; 
         FIG. 3  is a top elevational view of the valve seat of the fluid flow controller of  FIG. 1 ; 
         FIG. 4  is a cross-sectional view taken generally along the lines  4 - 4  of  FIG. 3 ; 
         FIG. 5  is a top isometric view of the valve seat of  FIGS. 1, 3, and 4 ; 
         FIG. 6  is a top elevational view of the valve housing of the fluid flow controller of  FIG. 1 ; 
         FIG. 7  is a cross-sectional view taken generally along the lines  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a top isometric view of the valve housing of  FIGS. 1, 6, and 7 ; 
         FIG. 9  is a cross-sectional view of the valve seat of  FIGS. 1 and 3-5  disposed within the valve housing of  FIGS. 1 and 6-8 ; 
         FIG. 10  is a cross-sectional view similar to the view of  FIG. 1  after the valve seat has been pushed away from the check valve toward an upper portion of the valve housing against the bias of a spring; and 
         FIG. 11  is a graph depicting a flow rate versus a pressure drop across the check valve of  FIGS. 1 and 2  for various spring loads. 
     
    
    
     Other aspects and advantages of the present disclosure will become apparent upon consideration of the following detailed description, wherein similar structures have like or similar reference numerals. 
     DETAILED DESCRIPTION 
     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, specific embodiments are 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. 
     Referring to  FIG. 1 , 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 lower 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. 
     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. 
     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. 
     Referring to  FIG. 1 , a fluid flow controller  60  is depicted within the filter assembly  20 . The fluid flow controller  60  includes a check valve  62 , as seen in  FIGS. 1 and 2 , retained between the lower end  32  (for example, the end cap  50 ) of the filter element  28  and a top or inner side  63  of the end plate  36 . The check valve  62  may include a first portion  64  that is generally horizontal when positioned within the filter assembly  20 , a second, angled portion  66  extending at an angle from a first end  68  of the first portion  64 , and a third, generally vertical portion  69  extending at an angle of, for example, 90 degrees from a second end  70  of the first portion  64 . The first portion  64  of the check valve  62  controls flow of fluid through a first inlet opening or openings  72  in the end plate  36  and the second portion  66  of the check valve  62  controls fluid flow through a second inlet opening or openings  74 . The generally vertical portion  69  aligns the check valve  62  during manufacturing and keeps the check valve  62  aligned during use. Any suitable number of first inlet opening(s)  72  and/or second inlet opening(s)  74  may be provided. 
     As best seen in  FIG. 2 , one or more projections  80 , such as rounded projections, may extend outwardly from a lower surface  82  of the first portion  64  of the check valve  62 . The projections  80  may be full annular projections in order to create the appropriate seal against the end plate  36 . Still further, the projections  80  may have any shape. A free end  84  of the second portion  66  may be bulbous. The projections  80  and the bulbous free end  84  elevate the first and second portions  64 ,  66  of the check valve  62  to provide a gap between elastomeric surfaces of the check valve  62  and the end plate  36  in order to distribute pressure evenly across surfaces of the check valve  62 . The check valve  62  may be made of rubber, plastic, an elastomeric material, or any other suitable material. 
     An outlet opening  90  is provided centrally within the end plate  36 . As seen in  FIG. 1 , the outlet opening  90  may be centrally disposed about a longitudinal axis  92  of the filter assembly  20 . While the outlet opening  90  is depicted as being circular in cross-section, the outlet opening  90  may have any other suitable configuration depending on the application for the filter assembly  20 . Still optionally, the outlet opening  90  may be oriented in any suitable manner. 
     Referring to  FIGS. 1 and 9 , a valve seat  100  is disposed within a valve housing  102  to allow longitudinal movement of the valve seat  100  within the valve housing  102 , as will be discussed in greater hereinafter. As best seen in  FIGS. 3-5 , the valve seat  100  includes an annular U-shaped body  104  having an inner annular wall  106  and an outer annular wall  108  connected by a wall  110  that extends generally perpendicular to the inner and outer annular walls  106 ,  108 . A first plurality of projections  114  extend outwardly from an upper edge  116  of an outer surface  118  of the outer annular wall  108 . In an illustrative embodiment, four projections  114  may be utilized in which each of the projections  114  is spaced at an angle A 1  of, for example, 90 degrees from each adjacent projection  114 . In other illustrative embodiments, any suitable number of projections  114  may be utilized and/or the projections  114  may be spaced at any angle from adjacent projections  114 . In further illustrative embodiments, the spacing between adjacent projections  114  need not be the same. 
     A second plurality of projections  130  extend inwardly from an upper edge  132  of an inner surface  134  of the inner annular wall  106 . In an illustrative embodiment, four projections  130  may be utilized in which each of the projections  130  is spaced at an angle A 2  of, for example, 90 degrees from each adjacent project  130 . In other illustrative embodiments, any suitable number of projections  130  may be utilized and/or the projections  130  may be spaced at any angle from adjacent projections  130 . In further illustrative embodiments, the spacing between adjacent projections  130  need not be the same. 
     Still referring to  FIGS. 1, 3-5, and 9 , the projections  114  may be offset from the projections  130 , for example, the projections  114  may be spaced at an angle A 3  of, for example, 45 degrees from each adjacent projection  130 . As would be understood by one skilled in the art, the projections  114  may be aligned with the projections  130  or may be offset at any suitable angle. 
     As seen in  FIGS. 1 and 6-9 , the valve housing  102  includes a generally U-shaped body  140  having an inner annular wall  142  and an outer annular wall  144  connected by a rounded end wall  146 . In illustrative embodiments, the inner annular wall  142  has a height H 1  that is less than a height H 2  of the outer annular wall  144 , the function of which will be described in detail hereinafter. An annular flange  147  extends outwardly from a free end  149  of the outer annular wall  144 . A first plurality of longitudinally extending slots  150  are disposed through the outer annular wall  144 . In an illustrative embodiment, four slots  150  may be utilized in which each of the slots  150  is spaced at an angle A 4  of, for example, 90 degrees from each adjacent slot  150 . In other illustrative embodiments, any suitable number of slots  150  may be utilized and/or the slots  150  may be spaced at any angle from adjacent slots  150 . In further illustrative embodiments, the spacing between adjacent slots  150  need not be the same. The number and spacing of the slots  150 , in an illustrative embodiment, is the same as the number and spacing of the projections  114  extending from the outer surface  118  of the outer annular wall  108 , such that the projections  114  fit within the slots  150 , as will be discussed in more detail below. 
     A second plurality of longitudinally extending slots  160  are disposed through the inner annular wall  142 . In an illustrative embodiment, four slots  160  may be utilized in which each of the slots  160  is spaced at an angle A 5  of, for example, 90 degrees from each adjacent slot  160 . In other illustrative embodiments, any suitable number of slots  160  may be utilized and/or the slots  160  may be spaced at any angle from adjacent slots  160 . In further illustrative embodiments, the spacing between adjacent slots  160  need not be the same. The number and spacing of the slots  160 , in an illustrative embodiment, is the same as the number and spacing of the projections  130  extending from the inner surface  134  of the inner annular wall  106 , such that the projections  130  fit within the slots  160 , as will be discussed in more detail below. 
     Still referring to  FIGS. 1 and 6-9 , the slots  150  may be offset from the slots  150 , for example, the slots  150  may be spaced at an angle A 6  of, for example, 45 degrees from each adjacent slot  160 . As would be understood by one skilled in the art, the slots  150  may be aligned with the slots  160  or may be offset at any suitable angle. Regardless, in an illustrative embodiment, the slots  150 ,  160  may be arranged in the same manner as the projections  114 ,  130 . 
     In use, each of the projections  114  of the valve seat  100  are aligned within one of the slots  150  in the valve housing  102 . Similarly, each of the projections  130  of the valve seat  100  is disposed within one of the slots  160  in the valve housing  102 . In this manner, the projections  114 ,  130  are positioned for longitudinal movement within the slots  150 ,  160 , as will be discussed in greater detail below. 
     The check valve  62  may be made of Nitrile, Silicone rubber, or any other suitable material. The valve seat  100  and the valve housing  102  may be made of the same or different materials including, but not limited to, Nylon 6 with glass filling or Nylon 66 with glass filling. The materials for the check valve  62 , the valve seat  100 , and the valve housing  102  must be suitable for use with engine oil at up to 300 degrees Fahrenheit for several thousand miles. 
     As best seen in  FIGS. 1, 9, and 10 , a spring  162  is disposed within a cavity  164  formed between the U-shaped body  104  of the valve seat  100  and the U-shaped body  140  of the valve housing  102 . In a non-operating condition or in an operating condition in which a predetermined pressure has not been met, the spring  162  biases the valve seat  100  to a position in which the projections  114 ,  130  are disposed at lowermost positions within respective slots  150 ,  160 , as seen in  FIG. 1 . As will be discussed in more detail below, when a predetermined pressure is met, the valve seat  100  may be moved along the valve housing  102 , whereby the projections  114 ,  130  ride along the slots  150 ,  160  to upper positions within respective slots  150 ,  160 , as best seen in  FIG. 10 . While the projections  114 ,  130  are shown about half of the way up the slots  150 ,  160 , the projections  114 ,  130  may be disposed at any point along the slots  150 ,  160 , including uppermost edges of the slots  150 ,  160 . 
     The assembly and operation of the filter assembly  20  and the fluid flow controller  60  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 . 
     As best seen in  FIGS. 1, 9, and 10 , the fluid flow controller  60  is assembled by positioning the annular flange  147  of the valve housing  102  positioned adjacent a lower end  32  of the filter assembly  20  or the end cap  50 . The valve seat  100  is positioned within the valve housing  102  such that the valve housing  102  encloses the valve seat  100 . More particularly, each of the projections  114  of the valve seat  100  is disposed within one of the slots  150  in the valve housing  102 . Similarly, each of the projections  130  of the valve seat  100  is disposed within one of the slots  160  in the valve housing  102 . Optionally, the valve seat  100  and the valve housing  102  may be assembled and, thereafter, positioned with the flange  147  adjacent a lower end  32  of the filter assembly  20  or the end cap  50 . The longitudinal extent of the slots  150 ,  160  allows for movement of the projections  114 ,  130  along the slots  150 ,  160 , respectively, to allow movement of the valve seat  100  within the valve housing  102 , as will be discussed in greater detail below. 
     Still referring to  FIGS. 1, 9, and 10 , the check valve  62  is positioned adjacent the valve seat  100  and the valve housing  102 . More specifically, an outer surface  170  of the wall  110  of the U-shaped body  104  of the valve seat  100  may be adjacent an outer surface  172  of the first portion  64  of the check valve  62 . Further, the annular flange  147  of the valve housing  102  is sandwiched between the lower end  32  of the filter assembly  20  of the end cap  50  and the first portion  64  of the check valve  62 . The end plate  36  is positioned adjacent the check valve  62  such that the first portion  64  of the check valve  62  covers the first inlet opening(s)  72  and the second portion  66  of the check valve  62  covers the second inlet opening(s)  74 . The lid  38  may be disposed adjacent the end plate  36  for attachment to 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  60  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 valve housing  102  is positioned in the core  30  with an outer surface  180  of the outer annular wall  144  disposed adjacent the core  30 . As noted above, the annular flange  147  of the valve housing  102  is sandwiched between the lower end  32  of the filter assembly  20  of the end cap  50  and the first portion  64  of the check valve  62 . Still further, the valve seat  100  is biased by the spring  162  against the check valve  62 . These features form a liquid tight seal that prevents movement of fluid into the core  30  of the filter assembly  20  before a predetermined pressure flow is achieved. 
     Operation of the fluid flow controller  60 , once the filter assembly  20  is assembled and secured to the engine block, will now be described in detail. The resistance of the first portion  64  of the check valve  62  is greater than a resistance of the second portion  66 . More specifically, the elastomer of the second portion  66  insures that a pressure necessary to move the second portion  66  and open the second inlet opening(s)  74  is less than a pressure necessary to move the first portion  64  and open the first inlet opening(s)  72 . In an illustrative embodiment, the second portion  66  of the check valve  62  may open the second inlet opening(s)  74  at a minimum opening pressure, for example, 1 pound per square inch (psi) and the first portion  64  of the check valve may open the first inlet opening(s)  72  at a predetermined higher pressure, for example, on the order of 8-10 psi. 
     The elastomeric material of the first portion  64  of the check valve  62  and/or the resistance of the properties of the spring  162  (e.g., the gauge, the material, the spring rate, the tensile strength, the hardness, the modulus of elasticity, the thickness, and/or any other spring properties) may be varied to vary the pressure necessary to move the first portion  64  of the check valve  62 . 
     In operation, the filter assembly  20  is spun onto a stud on the engine block, which engages threads in the central outlet opening  90  in the end plate  36 , and is secured in place. A gasket may engage the engine block and preclude fluid flow between the engine block and the filter assembly  20 . While a particular gasket, end plate, and lid are described, any suitable gasket, end plate, 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  20  through the second inlet opening(s)  74 . Slight pressure will move the second portion  66  of the check valve  62  away from the second inlet opening(s)  74  and oil will flow through the second inlet opening(s)  74 , the filter media of the filter element  28 , and will be discharged through the central outlet opening  90  for return to the engine. 
     When the engine is turned off, the second portion  66  of the check valve  62  will close the second inlet opening(s)  74  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 first portion  64  of the check valve  62  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 first portion  64  of the check valve  62  will open, thereby pushing the valve seat  100  upwardly or inwardly into the valve housing  100 . As discussed in detail above, the projections  114 ,  130  of the valve seat  100  ride along the slots  150 ,  160  of the valve housing  102  to upper positions within respective slots  150 ,  160 , as best seen in  FIG. 10 . Movement of the valve seat  100  along the valve housing  102  allows the first portion  64  of the check valve  62  to open, as seen in  FIG. 10 , thereby permitting the flow of oil through the first inlet opening(s)  72  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 first inlet opening(s)  72  and open the first portion  64  of the check valve  62  to permit oil to bypass the filter media and exit the filter assembly  20  through the central outlet opening  90  for return to the engine. The height difference (H 2 −H 1 ) of the outer and inner walls  144 ,  142  of the valve housing  102  provides a gap for flow of oil directly into a central portion of the filter assembly  20 , as depicted by the arrows in  FIG. 10 . 
     During operation, the spring  162  provides the desired amount of predetermined resistance to moving the first portion  64  of the check valve  62  and opening the first inlet opening(s)  72 . More particularly, the spring  162  is designed with a particular resistance value (based on any number of spring properties, such as a gauge, spring rate, tensile strength, hardness, modulus of elasticity, thickness, and/or 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 value of the first portion  64  of the check valve  62  may be different for different filter assemblies and/or applications. The spring  162  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 first inlet opening(s)  72 . 
     In any of the embodiments herein, a resistance or load on the spring when assembled in the fluid flow controller may be determined by multiplying a surface area of the check 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. 
     While the valve seat  100  and the valve housing  102  are depicted and described as having particular shapes, the shapes thereof may vary without departing from the scope of the present application. 
       FIG. 11  depicts a flow rate versus a pressure drop across the check valve  62  of  FIGS. 1, 2, and 10  for various spring loads. As noted previously, different spring loads may be employed depending upon a desired flow rate and pressure drop. 
     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.