Abstract:
A “no filter, no run” filtration system that is designed to verify that a filter cartridge is present to safe-guard against damage to fuel injectors, associated fuel components, etc. and engine malfunctions. Fuel flow to the engine is prevented altogether or permitted in an amount insufficient to allow engine operation if a filter cartridge is not installed, and an appropriately designed filter cartridge is required to be used in order to permit sufficient fuel flow for engine operation. In one embodiment, a flow restriction valve is provided that includes a ball.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part application of U.S. Ser. No. 11/780,176 filed on Jul. 19, 2007, the contents of which are incorporated by reference herein in their entirety. 
    
    
     FIELD 
     This disclosure generally pertains to the field of filtration, and more particularly to fuel filtration systems designed to safe-guard against damage to fuel injectors, associated fuel components, and engine malfunctions resulting from a missing or incorrect fuel filter. 
     BACKGROUND 
     Fuel filtration systems are known that are designed to prevent flow of fuel to an engine if no filter cartridge is installed or in the incorrect filter cartridge is installed. In these “no filter, no run” systems, not only must a filter be present, but the correct filter must be used, in order to allow fuel to flow to the engine. 
     SUMMARY 
     A “no filter, no run” filtration system that is designed to verify that a filter cartridge is present to safe-guard against damage to fuel injectors, associated fuel components, etc. and engine malfunctions. Fuel flow to the engine is prevented altogether or permitted in an amount insufficient to allow engine operation if a filter cartridge is not installed, and an appropriately designed filter cartridge is required to be used in order to permit sufficient fuel flow for engine operation. 
     In one embodiment, a filter assembly includes a flow restriction valve controlling fluid flow to an outlet. The flow restriction valve includes a ball disposed on a sloped track, and the track includes a step that separates the sloped track into sloped track sections. The flow restriction valve is used in a filter housing, for example a fuel filter housing, that has a standpipe that incorporates the flow restriction valve to control fluid flow into a flow passage of the standpipe. 
     When a filter cartridge is not installed, or when an incorrect filter cartridge is installed, the ball is movable to a blocking position preventing flow into the standpipe. When the correct filter cartridge is installed, the ball is prevented from moving to the blocking position by a suitable blocking means. Suitable blocking means include a pin connected to a suitable part of the filter cartridge, for example an end plate or a center tube, a pin connected to a lid of the filter housing that is designed to extend downwardly through an end plate of the filter cartridge into a position to block the ball, or a pin that is installed separately from the filter cartridge. It is to be noted that the filter cartridge can be a filter-in-filter design, a single filter design, or any other type of filter design. 
     In another embodiment, a filter housing includes a housing body having a side wall and an end wall defining a filter cartridge space. The end wall forms a closed end of the filter cartridge space, and the body has an open end opposite the end wall. A standpipe extends from the end wall along a longitudinal axis into the filter cartridge space toward the open end. The standpipe is generally oval shaped in lateral cross-section, and includes an internal flow passage and an opening in the standpipe that places the internal flow passage in communication with the filter cartridge space. A generally oval, conically shaped structure is disposed at an upper end of the standpipe. The structure aids in automatically aligning a filter cartridge during installation. 
     In another embodiment, a filter cartridge includes a filter media suitable for filtering a fluid. The filter media has a first end, a second end opposite the first end, and a clean fluid side. A first end plate is connected to first end of the filter media, and a blocking pin is connected to the first end plate by ribs and extends into the clean fluid side. A skirt surrounds the blocking pin and the ribs. A second end plate is connected to the second end of the filter media. The second end plate includes a hole that allows passage of a fluid passageway member therethrough. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a filter assembly that includes a filter cartridge in a filter housing. 
         FIG. 2  is a perspective view of the filter housing with the lid removed to show the interior of the housing. 
         FIG. 3  is a detailed cross-sectional view of the filter cartridge. 
         FIG. 4  is a cross-sectional view of the outer filter upper end plate. 
         FIG. 5  is a perspective view of the inner filter upper end plate. 
         FIGS. 6A and 6B  are perspective and side cross-sectional views, respectively, of the inner filter lower end plate. 
         FIG. 7  is a cross-sectional view of the outer filter lower end plate. 
         FIG. 8  is a detailed view of the flow restriction valve at the upper end of the standpipe. 
         FIGS. 9A and 9B  are an end view and a side cross-sectional view, respectively, of the valve cage of the flow restriction valve. 
         FIGS. 10A ,  10 B and  10 C are a perspective view, a side view and a side cross-sectional view, respectively, of the valve cap of the flow restriction valve. 
         FIG. 11  is a top view of a seal for use in sealing the top opening of the valve cap. 
         FIG. 12  is an end view of an embodiment of an oval seal for sealing with the standpipe. 
         FIGS. 13A and 13B  illustrate another embodiment of a seal between a filter cartridge and the standpipe. 
         FIGS. 14A and 14B  illustrate yet another embodiment of a seal between a filter cartridge and the standpipe. 
         FIG. 15  illustrates an embodiment of a flow restriction valve using a separate pin to block the ball. 
         FIG. 16A  is a sectional perspective view of a housing body with a valve at the base of the filter housing. 
         FIG. 16B  is a perspective view of a bottom portion of a filter cartridge with a ventral fin useable with the embodiment of  FIG. 16A . 
         FIG. 16C  is a perspective view looking from above of the base of the filter housing of  FIG. 16A . 
         FIG. 16D  is a sectional perspective view of the filter cartridge partially installed in the filter housing. 
         FIG. 16E  is a sectional perspective view of the filter cartridge fully installed in the filter housing. 
         FIG. 16F  is a side view of the ventral fin of the filter cartridge of  FIG. 16B . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a filter assembly  10 , for example a fuel filter assembly, which is intended to filter a fluid, for example diesel fuel, and remove water from the fluid before the fluid reaches a protected system, for example a fuel injection pump and fuel injectors. This description will hereinafter describe the fluid as fuel. However, it is to be realized that the concepts described herein can be used for other fluids. In addition, in appropriate circumstances, the concepts described herein can be used to remove contaminants other than water from the fluid. And, in appropriate circumstances, one or more of the concepts described herein can be applied to other types of filter assemblies that filter other types of fluids, for example lubrication, hydraulic and other liquids, as well as air. 
     The assembly  10  includes a filter housing  12  that is designed to receive a filter cartridge  14  therein for filtering the fluid. The filter housing  12  includes a housing body that has a side wall  16  and an end wall  18 . The side wall  16  and the end wall  18  define a filter cartridge space  20  that is large enough to receive the filter cartridge  14  therein, with the end wall  18  forming a closed end of the space  20 . The housing body has an open end generally opposite the end wall  18 , with the open end in use being closed by a lid  22  that closes off the space  20 . The housing body also includes an inlet opening  24 , illustrated in  FIG. 2 , through which fuel to be filtered enters the space  20 , and an outlet  26 , illustrated as extending from the end wall  18 , through which fuel exits on its way to the engine. It is to be realized that the filter housing  12  could have other configurations than that described herein. 
     A fluid passageway member in the form of a standpipe  30  is secured to the end wall  18  and extends upwardly into the space  20  toward the open end and the cap  22 . In the illustrated embodiment, the standpipe  30  is generally hollow from its end  32  connected to the end wall  18  to a tip end  34  thereof, thereby defining an internal flow passage  36 . The flow passage  36  is in communication with the outlet  26  so that fuel that enters the standpipe  30  can flow from the standpipe and into the outlet  26  to the engine. The standpipe  30  is disposed in the housing  12  which has a central axis A-A. In some embodiments, the axis A-A of the housing  12  can be off-center of the housing. 
     With reference to  FIG. 2 , the standpipe  30  is illustrated as being oval-shaped from the end  32  to the tip end  34 . An example of an oval standpipe is disclosed in U.S. Pat. No. 6,884,349, which is incorporated by reference herein in its entirety. While this disclosure will describe the standpipe as being oval-shaped, it is to be realized that the concepts described herein could be used, individually or in various combinations, with a circular-shaped standpipe and with standpipes having other shapes. 
     A flow restriction valve  50  is disposed at the tip end of the standpipe  30  to control the flow of fuel into the standpipe. The valve  50  can prevent fuel flow into the standpipe when the filter cartridge  14  is not installed or when an incorrect filter cartridge is installed. In some embodiments described herein, when the filter cartridge  14  or other appropriately designed filter cartridge is installed, the filter cartridge is designed to interact with the valve in such a manner as to keep the valve from preventing fuel flow into the standpipe. An example of a valve operating in this manner is disclosed in U.S. Pat. No. 6,884,349. 
     Filter Cartridge 
     With reference to  FIGS. 1-3 , the filter cartridge  14  is illustrated as being of a filter-in-filter type with an inner filter  60  and an outer filter  62 . In the illustrated embodiment, the inner filter  60  is designed to snap-fit connect with the outer filter  62  during assembly of the cartridge  14  to form an integral unit. 
     The inner filter  60  includes a ring of filter media  64 , an upper end plate  66  secured to an upper end of the media  64 , and a lower end plate  68  secured to a bottom end of the media  64 . Likewise, the outer filter  62  includes a ring of filter media  70 , an upper end plate  72  secured to an upper end of the media  70 , and a lower end plate  74  secured to a bottom end of the media  70 . The end plates  66 ,  68 ,  72 ,  74  are formed of a suitable material, for example plastic. 
     Fuel can include water therein in different forms, including free water, e.g. droplets, and emulsified water. Preferably, the filter media  70  is designed so that free water is initially stripped out when fuel enters the filter from the outside. The free water does not penetrate the media  70  and remains substantially outside the filter. The media  70  also coalesces the majority of the emulsified water and separates the now coalesced water from the fuel. The media  70  also retains soft and solid contaminants from the fuel. Water, being heavier than fuel, settles down to the bottom of the filter cartridge  14 , and drains through openings to a water collection area at the base of the housing  12 . By the time the fuel interfaces with the media  64 , most of the water has been separated, and the media  64  filters particles from the fuel before the fuel enters the center of the filter cartridge. The media  64  also strips remaining water from the fuel and prevents the water from entering the media  64 . The filtered fuel then enters the standpipe  30  and flows to the outlet  26 , leading to a downstream protected component, for example a fuel pump. 
     The outside of the filter media  64  generally faces the interior of the filter media  70  of the filter  62 , with the inside of the ring of media  64  defining a clean or filtered fuel side of the filter cartridge  14  and the outside of the media  70  defining a dirty or unfiltered fuel side, whereby the filter cartridge is configured for outside-in flow. In appropriate circumstances, the concepts described herein can be applied to inside-out type flow filter cartridges. 
     The upper end plate  72 , as illustrated in  FIGS. 3 and 4 , includes a first generally circular, horizontal plate  80 . A flange  82  extends downwardly from the plate  80  and angles slightly outwardly, with the end of the flange  82  connected to a ring  84  that is generally horizontal. The bottom surface of the ring  84  is suitably attached to the upper end of the filter media  70 , for example using an adhesive or using heat to fuse the ring  84  to the filter media. 
     The plate  80  and the flange  82  define a hollowed-out area  86  that receives the end of the inner filter  60  as shown in  FIG. 3 . This permits use of a longer inner filter to increase the amount of filter media for filtering. 
     With reference to  FIGS. 1 and 4 , the edge of the plate  80  extends past the flange  82  to form a circumferential lip  90 . A mechanism is provided for connecting the lid  22  to the filter cartridge  14  via the end plate  72 . In particular, a plurality of resilient fingers  92  project downwardly from the lid  22 . Each finger  92  includes an enlarged end  94  by which the fingers  92  snap fit over the lip  90 . The lid  22  also includes internal threads  96  which engage with external threads  98  formed at the upper end of the side wall  16  by which the lid  22  can be screwed onto the housing body. 
     In use, the filter cartridge  14  can be connected to the lid  22  prior to inserting the cartridge into the housing, after which the lid  22  is threaded onto the side wall  16 . The fingers  92  can slide on the outer edge of the lip  90  to allow the lid  22  to rotate relative to the upper end plate  72 . Alternatively, the cartridge  14  can first be installed in the housing, and thereafter the lid  22  connected to the cartridge via the fingers  92  and the lid  22  threaded onto the wall  16 . Removal of the lid  22  occurs by unscrewing the lid and lifting the lid and cartridge  14  together from the housing. As the lid  22  is lifted upward, the ends  94  of the fingers  92  engage the lip  90 , causing the cartridge  14  to be lifted upwards as well. The cartridge  14  can then be removed from the lid  22  by manually deflecting the ends of the fingers  92  outward to disengage from the lip  90 . 
     If desired, a handle can be attached to the upper surface of the plate  80  to facilitate handling of the cartridge  14 , for example lifting of the cartridge from the housing. However, the lip  90  also provides a means to allow a user to grab the cartridge  14  and lift it from the housing. Therefore, the handle is optional. 
     Turning to  FIGS. 3 and 5 , the upper end plate  66  of the inner filter  60  includes a generally circular, horizontal plate  110 . The plate  110  includes a perimeter portion  112  that is suitably attached to the upper end of the filter media  64 , for example using an adhesive or using heat to fuse the portion  112  to the filter media  64 . A pin  114  projects downwardly from the center of the plate  110 . The pin  114  is designed to interact with the valve  50  in a manner to be described below. The pin  114  is connected to the plate  110  via four stiffening ribs  116  which provide stiffening to the pin  114 . 
     Extending downward from the plate  110 , and surrounding the pin  114  and ribs  116 , is a protective skirt  118 . The skirt  118  includes a solid circumferential base portion  120  that connects to the plate  110  and to the ends of the ribs  116 , and a plurality of spaced tabs  122  extending from the base portion  120 . The tabs  122  have a generally constant width from their point of attachment to the base portion  120  to tip ends thereof. A gap  124  is provided between each tab  122 , the purpose of which will be described below. 
     The lower end plate  68  of the inner filter  60  is illustrated in  FIGS. 3 ,  6 A and  6 B. The end plate  68  includes a generally ring shaped, horizontal plate  130  which is suitably attached to the bottom end of the filter media  64 , for example using an adhesive or using heat to fuse the plate  130  to the filter media. A standpipe hole  132  is formed at the center of the plate  130  which is configured to allow passage of the standpipe  30 . In the illustrated embodiment, the hole  132  is has a shape similar to the shape of the standpipe  30 , for example oval. However, if the standpipe has a different shape, for example circular, then the hole  132  can have a shape, for example circular, similar to the shape of the standpipe. 
     A seal support  134 , for example a flange, extends downwardly from the plate  130  for supporting a seal  138  (visible in  FIG. 3 ) designed to seal with the outside surface of the standpipe  30  when the filter cartridge is installed. The support  134  can extend around the entire perimeter of the hole  132 , or only around portions thereof. An inwardly extending ledge  136  is formed at the base of the support  134  for supporting the bottom of the seal  138 . The seal  138  extends over the majority of the height of the support  134  and includes an intermediate, inwardly extending ridge  140  that in use seals with the standpipe. 
     The seal  138  can have any shape suitable for sealing with the outside of the standpipe. For example, in the case of an oval shaped standpipe, the seal can be oval shaped; for a circular standpipe, the seal can be circular. In addition, the seal  138  can be secured to the support  134  in any suitable manner. For example, the seal  138  can be securing to the support  134  by interference fit, adhesives, etc. 
     A plurality of flexible connection arms  142  are connected to the bottom of the plate  130  near the outer edge thereof, and extend downwardly from the plate  130  at an angle a, for example  20  degrees. The arms  142  can be, in the illustrated example, positioned at equally spaced intervals around the plate, although the spacing could be other than equal. In addition, in the illustrated embodiment there are four arms  142 , although a larger or smaller number of arms  142  could be used. The arms  142  each extend at an angle so that ends  144  of the arms are positioned radially beyond the outer edge of the plate  130  ( FIG. 6B ). The arms  142  also help create a gap between the filter media  64 ,  70 . 
     The arms  142  are used to help connect the lower end plate  68  of the inner filter  60  to the lower end plate  74  of the outer filter  62 . The end plate  74 , illustrated in  FIGS. 3 and 7 , includes a generally ring-shaped, horizontal plate  150  which is suitably attached to the bottom end of the filter media  70 , for example using an adhesive or using heat to fuse the plate  150  to the filter media. The plate  150  surrounds a hole  152  through which the inner filter  60  can be inserted into the outer filter  62 . The hole  152  is defined by a flange  154  that extends downwardly from the plate  150  around the entire perimeter of the hole  152  to help define the hole. 
     An inwardly extending ledge  156  is formed at the base of the flange  154 . The ledge  156  forms a seat to receive the ends of the arms  142  of the lower end plate  68  of the inner filter  60  thereon as seen in  FIG. 3 . The outer diameter formed by the ends of the arms  142  is preferably greater than the inner diameter of the inner edge of the ledge  156  so that the arms  142  are compressed inward as the inner filter  60  is inserted into the outer filter  62 . Once the ends of the arms  142  clear the ledge  156 , the ends  144  spring outward to the position shown in  FIG. 3 . Thus, the design of the arms  142 , the flange  154  and the ledge  156  form a snap fit connection between the filters  60 ,  62 . In addition, relative rotational movement is permitted between the outer filter  62  and the inner filter  60  about the central axis A-A to permit alignment of the opening  132  with the standpipe  30 . 
     Returning to  FIG. 7 , a slot  158  is formed around the outer perimeter of the flange  154  of the lower end plate  74 . The slot  158  receives a seal  160  therein that is designed to seal with an interior surface of the side wall  16  of the housing as shown in  FIG. 1 . 
     Flow Restriction Valve 
     The flow restriction valve  50  will be described with reference to FIGS.  1  and  8 - 11 . The valve  50  is used to control the flow of fuel into the standpipe  30  and to the outlet  26 . In one embodiment described herein, the valve  50  is designed to prevent all flow of fuel into the standpipe  30  when no filter cartridge is installed or when an improper filter cartridge is installed, but permit flow into the standpipe when a correctly designed filter cartridge is installed. 
     In alternative embodiments described herein, the valve can be designed to allow limited flow of fuel into the standpipe  30  when no filter cartridge is installed or when an improper filter cartridge is installed. This limited flow allows lubrication of downstream components, such as a fuel pump, but is insufficient to allow the engine to operate. 
     The valve  50  will be described as being used with the filter cartridge  14  described above. However, it is to be realized that the concepts of the valve  50  can be utilized with other filter cartridge designs, such as with single stage filter cartridges. 
     The tip end  34  of the standpipe  30  is open, and the valve  50  is secured in the open tip end as shown in  FIG. 8 . The valve  50  includes a valve cage  170 , a valve cap  172 , and a ball  174 . The valve cage  170  includes a portion that is configured to fit within the end  34  of the standpipe  30 . In the case of the oval-shaped standpipe, the portion of the valve cage  170  within the standpipe will be generally oval-shaped to fit closely within the standpipe. 
     With reference to  FIGS. 8 ,  9 A and  9 B, the valve cage  170  has a side wall  180 , and a reduced diameter section  182  extends from the base of the side wall  180  that is press fit or otherwise secured into the end of the standpipe  30 . When inserted into the standpipe, the base of the reduced diameter section  182  rests on a shoulder  184  formed inside the standpipe. To aid in retaining the section  182  in the standpipe, the outer surface of the section  182  is provided with ribs  186  which engage with the interior surface of the standpipe. 
     The valve cage  170  is generally hollow and is divided by a wall  192  that extends from one side of the side wall  180  toward the opposite side. The wall  192  connects to a wall  194  that extends upwardly to a top wall  196  that connects to the opposite side wall  180 . As shown in  FIG. 9A , the wall  192  includes an arcuate section  200  that forms a track for the ball  174 . The section  200  slopes downward from the wall  194  to the side wall  180 . The wall  194  includes a circular opening  204  therein that places the exterior of the cage  170  in communication with the interior of the cage  170  and the flow passage  36 . The ball  174  is configured to roll along the track  200  and can block the opening  204  to prevent fuel flow into the standpipe. 
     As shown in  FIGS. 9A and 9B , the track  200  includes a step  206  that restricts the ball  174  from inappropriately rolling up the track  200  and blocking the opening  204 . The step  206  separates the track  200  into a first track section  200   a  and a second track section  200   b . In addition, the wall  194  is disposed at an acute angle β, for example about 85 degrees, relative to a horizontal axis. Angling of the wall  194  in this manner minimizes the chances of the ball  174  getting stuck in position blocking the opening  204 . Further, a rib  208  is disposed inside the cap  170  immediately behind the opening  204 . The rib  208  limits how far the ball  174  can penetrate into the opening  204  which aids in preventing the ball  174  from remaining in a position blocking the opening  204 . 
     The cage  170  also includes an opening  222  that is formed through the side wall  180  that place the exterior of the cage  170  in fluid communication with the interior of the cage  170 , and thus in communication with the opening  204  and the interior of the standpipe. The opening  222  is positioned on the side wall  180  at a position that is adjacent to the lower end of the track  200  such that when the ball  174  is at the lower end of the track, as shown in  FIG. 8 , the ball  174  is disposed in the opening  222 . 
     The vertical height of the opening  222  is such that the ball  174  cannot escape out the opening  222 . In addition, in the illustrated embodiment, the opening  222  is shaped such that the ball  174  cannot block the entire opening  222  and fuel can flow into the interior of the cage  170  when the ball  174  is in the opening  222 . For example, the opening  222  is shown as being generally oblong which, when the ball is at the position shown in  FIG. 8 , permits fuel to flow between the sides of the ball  174  and the ends of the opening  222  and into the cage  170 . 
     With reference to FIGS.  8  and  10 A-C, the valve cap  172  is oval-shaped and designed to be secured to the top of the valve cage  170 . The cap  172  can be secured to the cage  170  in any suitable manner, for example with an adhesive or using a thermal bond. When in place, the valve cap  172  fits over the valve cage  170  to confine the ball  174  in the cage. 
     The side wall  224  of the cap  172  is generally conically shaped and an opening  226  extends through the top of the cap. The opening  226  permits the pin  114  on the filter cartridge  14  (or other pin designs described herein) to extend therethrough when the cartridge is installed, with the pin  114  extending to a position adjacent the track  200  as shown in  FIG. 8 . In that position, the pin  114  prevents the ball  174  from moving up the track  200  and blocking the opening  204  when the cartridge  14  is installed. 
     A pair of protrusions  230 ,  232  are formed on the side wall  224 , with the protrusions  230 ,  232  including angled outer edges  234 ,  236 . If the filter cartridge  14  is not in the proper orientation during installation, the protrusions  230 ,  232  will cause the filter cartridge  14  to rotate to the correct orientation as a result of engagement between the opening  132 /seal  138  on the end plate  68  and the protrusions  230 ,  232 , with the angled edges  234 ,  236  creating a sideways rotational force to cause the rotation of the filter cartridge. The oval, conically shaped side wall  224  without protrusions could also achieve this auto-alignment. Therefore, the protrusions  230 ,  232  are optional. 
     The operation of the valve  50  should be apparent from the description above. When the filter cartridge  14  is not installed, gravity causes the ball  174  to move to the end of the track  200  to the position shown in  FIG. 8 . When sufficient fuel pressure acts on the ball  174  with no filter cartridge present, the ball  174  is forced up the track  200  to the closed position blocking the hole  204 . 
     Upon installation of the filter cartridge  14 , the pin  114  extends downward to the position shown in  FIG. 8 , blocking the ball from moving up the track  200  to the closed position. In addition, the tabs  122  of the protective skirt  118  extend downward and surround the cage  170  and cap  172 . As seen from  FIG. 8 , the tabs  122  extend downward to a position adjacent the hole  222  and the ball  174 . The gaps  124  between the tabs  122  allow fuel to flow between the tabs  122  and into the opening  222 , and ultimately into the standpipe. 
     Since the pin  114  blocks the track  200 , the ball  174  cannot move to a position blocking the opening  204 . Under operating conditions, the pressure of the fuel will force the ball up the track and into engagement with the pin  114 . The opening  222  will be open allowing a maximum amount of fuel to enter the opening  222 . The fuel flows past the ball  174  and pin  114 , into the opening  204 , and into the flow passage  36  of the standpipe to the outlet  26 . 
     In one embodiment, when the ball  174  seats in the opening  204  when no filter cartridge (or an incorrect filter cartridge) is installed, the flow of fuel into the standpipe is substantially completely prevented. In another embodiment, when the ball  174  seats in the opening  204 , some fuel can be permitted to flow into the standpipe. The amount of fuel allowed past the ball  174  should be insufficient to permit engine operation, but sufficient to provide lubrication to downstream components, for example the fuel pump, in the case of diesel fuel. Since fuel flow need not be completely prevented, the ball and the opening  204  described herein can be manufactured to less exacting tolerances, which reduces the cost of manufacture. For example, the opening  204  could be formed with a shape that is similar to the shape of the opening  222 , whereby when the ball seats in the opening  204  fuel can still flow past the ball. In other designs, the ball and/or the wall defining the opening  204  can be manufactured with grooves, channels or the like to permit fuel flow past the ball. 
     Therefore, the word prevention as used herein, unless indicated otherwise either in the written description or claims, is meant to include complete shut off of fuel into the standpipe as well as including some flow of fuel into the standpipe, as long as the amount of fuel that passes is insufficient to permit engine operation. 
       FIG. 11  illustrates a seal  450  that can fit in the opening  226  at the top of the cap  172  (see  FIG. 10A ). The seal  450  prevents excessive entry of dirty, unfiltered fuel into the standpipe through the opening  226 . The seal  450  is provided with a cross split hole  452  that allows passage of the pin  114  through the seal  450  and down toward the ball track to block the ball. 
       FIG. 12  illustrates a seal  470  that is a variation of the seal  138  used on the end plate  68  (see  FIG. 3 ). The seal  470  is designed as a snap-on seal that engages via a snap fit with the flange on the end plate  68 . The seal  470  includes a plurality of tabs  472  extending outwardly from the perimeter thereof that engage in grooves formed on the end plate  68  to help retain the seal in place. 
       FIGS. 13A and 13B  illustrate a variation of a sealing arrangement between a standpipe  600  and a filter cartridge  602 . In this embodiment, a sealing plate  604  is provided that can be installed around the standpipe  600 . When the standpipe  600  is oval shaped, an oval shaped seal  606  (or a round seal if a round standpipe is used) is fixed to the sealing plate  604  prior to installing the plate  604 . When the plate  604  is installed on the standpipe  600 , the seal  606  seals with the outside surface of the standpipe  600  to prevent leakage of unfiltered fuel. The outside surface  608  of the plate  604  is circular and is illustrated as being generally vertical and planar. The filter cartridge  602  can include a circular seal  610  that seals with the surface  608  of the plate  604  when the cartridge is installed. This embodiment permits the filter cartridge  602  to have a circular seal design at the bottom thereof. However, the standpipe  600  and filter cartridge  602  can incorporate one or more of the other concepts described above. 
       FIGS. 14A and 14B  illustrate an embodiment where a filter cartridge  650  includes an oval shaped opening  652  in a bottom end plate  654 . An oval shaped gasket groove  656  surrounds the opening  652 . A circular seal  658  is disposed in the oval shaped gasket groove  656 . As the filter cartridge  650  is installed onto an oval shaped standpipe  670 , the seal  658  will conform to the oval shape of the standpipe  670  and groove  656 , creating a seal that is oval in shape. 
     The pin  114  has been described above as being connected to the end plate  66 . However, alternative designs are possible.  FIG. 15  illustrates an embodiment where a separate pin  700  is inserted into an opening in the upper end of a flow control valve  702  to block a ball  704  and prevent the ball from blocking an opening  706 . A filter cartridge  708  without a pin connected thereto can then be installed. The filter cartridge  708  is illustrated as being a single stage filter cartridge, although a filter-in-filter design similar to the filter cartridge  14  described above except with the pin  114  and the skirt  118  removed can be used. The pin  706  can be any shape or size, as long as it is able to block the ball  704 . 
     Many of the concepts described above have utilized a standpipe in the filter housing. However, many of the concepts described herein can be implemented on fuel filter housings without standpipes. 
     For example,  FIGS. 16A-F  illustrate a flow restriction valve that includes a ball implemented at the base of a filter housing that is devoid of a standpipe. With reference to  FIG. 16A , a ball  920  is placed inside a sink  921  and is seated on an opening  905  of a fuel outlet  924 . The outlet  924  is placed at the bottom of the sink  921 , which is part of a filter housing  922 . The fuel outlet  924  can have an oval-shaped cross-section or it can have a circular shaped cross-section. 
     Adjacent to the ball  920  inside the sink  921  is a bellow gasket  926 . The bellow gasket  926  is attached to a side wall  919  of the sink  921 , and is connected to a return channel  930  that leads back to a fuel tank (not shown). In a closed position ( FIG. 16A ), the ball  920  prevents fluid from entering the outlet  924 , such that fuel is forced to enter the bellow gasket  926  and flows back to the fuel tank through the return channel  930 . 
     Movement of the ball  920  to an open position occurs as a result of installing a correct filter cartridge  900 . With reference to  FIG. 16B , the cartridge  900  includes a circular endplate  903  and a bottom protrusion  902 . The endplate  903  is attached to the bottom region of the filter cartridge  900  and has a diameter that is larger than the filter media  907  of the cartridge  900 . The endplate  903  has a clean fuel passageway (not shown) that is generally circular along its length. The endplate  903  is provided with a notch  915 , such that the notch keys with a corresponding ridge  916  inside the housing  922 . The notch  915  and ridge  916  prevent rotation of the cartridge  900  in the housing, and also ensures that the correct filter cartridge is installed. 
     The bottom protrusion  902  is generally cylindrically shaped and is hollow. It has a diameter generally corresponding to that of the clean fuel passageway of the endplate  903 . The base opening  908  of the bottom protrusion  902  is provided with a thin ventral fin  950  that runs across the center of the opening  908 . The ventral fin  950  is designed to cause movement of the ball  920  to an open position when the cartridge  900  is installed. The ventral fin  950  has a slanted edge  906 , which has an acute angle alpha relative to a central, longitudinal axis A-A ( FIG. 16F ), and a vertical edge  904  generally parallel to the axis A-A. The fin  950  is thin enough to slide through a central slit  914  of a washer  912  ( FIG. 16C ). The central slit  914  of the washer  912  positions the cartridge  900 , and a plurality of holes  910  in the washer  912  allows fuel to pass through. 
     With reference to  FIGS. 16A ,  16 D and  16 E, the washer  912  is placed on a rim  932  of the sink  921 . The rim  932  and the sink  921  are generally circular. The sink  921  has a depth that is larger than the diameter of the ball  920 , and larger than the height of the bellow gasket  926 . The opening  905  of the outlet  924  is positioned in the center of the sink  921 . The bottom surface  933  of the sink  921  is provided with a bottle shaped channel  934 . The bottle shaped channel  934  facilitates movement of the ball  920  toward the bellow gasket  926  when the cartridge  900  is installed. 
     The cartridge  900  is installed by aligning the notch  915  with the ridge  916  and inserting the ventral fin  950  through the slit  914  of the washer  912 . When the ventral fin  950  extends through the slit  914 , the slanted region  906  of the ventral fin  950  pushes the ball  920  in a horizontal direction relative to the axis A-A toward the bellow gasket  926 . When the flat end  909  on the tip of the ventral fin  950  sits inside the neck of the bottle shaped channel  934 , the ball  920  is in an open position, seated in the bellow gasket to prevent fuel from entering the bellow gasket  926  and to allow fluid to flow through the outlet  924 . 
     The ball  920  can be designed to prevent all fuel flow into the outlet  924  when the ball is at the closed position. Alternatively, the ball  920  can be designed to permit limited fuel flow into the outlet  924  when closed. For example, grooves or slots can be formed on the ball  920  and/or on the wall defining the opening  905  that allow limited fuel flow when the ball is at the closed position. How limited fuel flow is permitted past the ball  920  is not critical, so long as the amount of fuel flow permitted at the closed position is insufficient to allow the engine to operate. 
     The invention may be embodied in other forms without departing from the spirit or novel characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.