Abstract:
A valve assembly includes a housing. A membrane supported by the housing such that the membrane covers a vapor passage defined by the housing. The membrane allows the passage of vapor through the membrane and prevents the passage of liquid through the membrane. A flow control feature is supported by the housing and at least partially controls flow of a vapor to the vapor passage. The flow control feature enables variable flow of vapor to the vapor passage.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional application of U.S. patent application Ser. No. 12/406,231, filed Mar. 18, 2009, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The invention relates to a valve assembly with a vent flow bypass for a tank, such as a fuel tank. 
     BACKGROUND OF THE INVENTION 
     Fuel tank valve assemblies that control the fluid level within the tank and provide nozzle shutoff are known. The fuel tanks must include vapor venting ability for gasses within the tank to maintain balanced pressure as the fuel levels within the tank change. Additionally, these valve assemblies often provide protection from liquid escaping during roll over conditions. However it is also desirable to prevent liquid from escaping due to sloshing of the liquid under normal conditions. 
     SUMMARY OF THE INVENTION 
     A valve assembly is provided. The valve assembly includes a housing. The valve assembly can be for a tank, in which case a portion of the housing can be located at least partially outside of the tank. The housing defines a vapor passage. A membrane is supported by the housing such that vapor must flow through the membrane to enter the vapor passage. The membrane is configured to allow the passage of the vapor and prevent the passage of a liquid through the membrane. A flow control feature is supported by the housing to at least partially control flow of vapor through the membrane to the vapor passage by providing variable flow to the vapor passage. 
     The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic fragmentary cross-sectional illustration of a valve assembly mounted to a fuel tank; 
         FIG. 2  is a schematic cross-sectional illustration of a membrane carrier for the valve assembly of  FIG. 1 ; 
         FIG. 3  is a schematic end view illustration of the membrane carrier for the valve assembly of  FIGS. 1 and 2 ; 
         FIG. 4  is a schematic cross-sectional illustration of another embodiment of a valve assembly; 
         FIG. 5  is a schematic cross-sectional illustration of third embodiment of a valve assembly; and 
         FIG. 6  is a schematic cross-sectional illustration of a fourth embodiment of a valve assembly. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, wherein like reference numbers refer to like components,  FIG. 1  shows a valve assembly  10  mounted to a fuel tank  12 . The valve assembly  10  has a housing  14 . A first housing portion  16  is located primarily within the fuel tank  12 . A second housing portion  18  is located primarily outside of the fuel tank  12 . The housing  14  also defines a vapor passage  20 , also referred to as a vent opening, which is in fluid communication with a vapor outlet  22 . The vapor outlet  22  leads to a vapor recovery canister (not shown) or other destination outside of the tank  12 . 
     The first housing portion  16  is inserted within a tank hole  24  in the fuel tank  12 . The first housing portion  16  could also be mounted externally with a passageway that allows communication with the interior of the tank. The first housing portion  16  includes a flange  26  which is located outside of the fuel tank  12  to prevent the valve assembly  10  from passing entirely through the tank hole  24  and into the fuel tank  12 . The second housing portion  18  is sometimes referred to as the vapor recovery side of the housing  14 . The second housing portion  18  is secured to the first housing portion  16  at the flange  26 . A carrier  28  is located between the first housing portion  16  and the second housing portion  18 . Securing the second housing portion  18  on the first housing portion  16  retains the carrier  28  to the housing  14 . 
       FIG. 2  illustrates an enlarged cross-sectional view of the carrier  28  and  FIG. 3  illustrates a bottom view of the carrier  28  of  FIG. 1 . The carrier  28  is generally annular in shape having a main body  30 . At least one finger  32  protrudes upwardly from the main body  30 . The finger  32  corresponds to indentations  34  (shown in  FIG. 1 ) on the second housing portion  18  when the carrier  28  is assembled with the housing  14 . As discussed above, and illustrated in  FIG. 1 , the main body  30  is secured between the first housing portion  16  and the second housing portion  18  when the valve assembly  10  is assembled. The annular shape of the carrier  28  defines a carrier opening  36  through which vapor within the fuel tank  12  can vent through to the vapor vent passage  20  (shown in  FIG. 1 ). A membrane  38  is secured to the carrier  28  and extends over the entire carrier opening  36 . The membrane  38  is of a material that allows vapor to pass through the membrane  38  but prohibits liquid from passing through. The membrane may be secured to the carrier  28  by weld, adhesive, heat sealing, insert molding, or other methods. One skilled in the art would know the appropriate attachment required for a particular carrier  28  and membrane  38  arrangement. 
     The carrier  28  includes at least one flow control feature  39 . In the embodiment shown the flow control feature  39  is a deflector  40 . As the membrane  38  is exposed to liquid, the liquid may slow the flow rate of the vapor through the membrane. Thus, the deflector  40  deters liquid from reaching the membrane  38  to help maintain the vapor flow rate through the membrane  38  at a predetermined level. 
     The deflector  40  extends downwardly and inwardly from the main body  30  of the carrier  28 . The deflector  40  defines at least one deflector opening  42  and may define a plurality of deflector openings. The deflector  40  would assist in directing liquid away from the membrane  38  and the vapor vent passage  20  while the deflector opening  42  allows vapor to pass the deflector  40  and exit the fuel tank  12  through the membrane  38 . The size and number of deflector openings  42  may be set to control the maximum amount of vapor that may pass through at one time. Additionally, the deflector  40  may include several layers of material with deflector openings  42  at various locations on each layer of the deflector  40 . This would create a tortuous flow path further assisting in deflecting liquid away from the membrane  38 . 
     The carrier  28  may also include a plurality of ribs  44  extending upwardly from the deflector  40 . The ribs  44  are arranged radially on the deflector  40  and provide support for the membrane  38  and assist in stiffening the deflector  40 . Additionally, the flow control feature  39  may include optimizing the size of the carrier opening  36  to control the maximum flow rate of the vapor that may exit the fuel tank  12  at one time. 
       FIG. 4  illustrates a second embodiment of a valve assembly  110  having a carrier  128  for use with a fuel tank  12  (shown in  FIG. 1 ). The carrier  128  is mounted to a housing  114 . The carrier  128  includes a main body  130 . At least one finger  132  protrudes upwardly from the carrier  128  to assist in securing the carrier  128  to the housing  114 . The main body  130  defines a carrier opening  136 . A membrane  138  is secured to the main body  130  to cover at least the carrier opening  136 . The membrane  138  may be larger in size than the carrier opening  136 . The size of the carrier opening  136  may be determined based upon the maximum desired vapor flow through the housing  114  to a vapor vent passage  120 . 
     The membrane  138  is illustrated in as a generally flat membrane. However, the membrane  138  may also be a cylinder or may be pleated to increase the surface area of the membrane  138 . One skilled in the art would know the proper shape for a membrane  138  for a particular valve assembly  110  arrangement. 
     A flow control feature  139  for the valve assembly  110  is a head valve. The flow control feature  139  includes a disc (or plate)  146 . The disc  146  is located above the carrier  128  within the vapor vent passage  120 . The disc  146  defines a disc opening  148  through which vapor may exit the fuel tank  12  (shown in  FIG. 1 ). The disc opening  148  is smaller in diameter than the carrier opening  136  and is sized to control the amount of flow at a given pressure inside the tank. When the vapor pressure within the fuel tank  12  reaches a sufficient level the disc  146  is lifted off the carrier  138 , as shown. The vapor may exit through the disc opening  148  and around the sides of the disc  146 , as illustrated by arrows V. The finger  132  assists in guiding the disc  146  in the proper position with respect to the carrier  128 . As the vapor escapes the fuel tank  12  the pressure within the fuel tank  12  decreases and the disc  146  returns to the resting position on the carrier  128 . Vapor may still exit the fuel tank through the disc opening  148  but will not exit around the disc  146  until the pressure again increases to a level that will raise the disc  146  off the carrier  128 . 
     The carrier  128  may also include flange protrusions  150  extending downward from the main body  130 . The flange protrusions  150  assist in attaching the membrane  138  to the carrier  128 . The membrane  138  may be attached by weld, adhesive, heat sealing, insert molding, or other methods. One skilled in the art would know the appropriate attachment required for a particular carrier  128  and membrane  138  arrangement. 
       FIG. 5  illustrates another embodiment of a valve assembly  210 . The valve assembly  210  has a housing  214 . The valve assembly  210  has a housing  214  with features that define at least one passageway  242 A and  242 B for vapor flow. The housing  214  interfaces with the fuel tank (not shown). 
     A membrane  238  is secured to the housing  214  to cover at least the first housing opening  242 A and the second housing opening  242 B. The size of the first housing opening  242 A and of the second housing opening  242 B may be determined based upon the maximum desired vapor flow through the housing  214  to a vapor passage  220  also defined by the housing. The membrane  238  is illustrated in as a generally flat membrane. However, the membrane  238  may also be a cylinder or may be pleated to increase the surface area of the membrane  238 . One skilled in the art would know the proper shape for a membrane  238  for a particular valve assembly  210  arrangement. The membrane directly covers the housing  214  at the openings  242 A and  242 B. 
     A flow control feature  239  for the valve assembly  210  is a head valve which includes a ball  246  located within the second housing opening  242 B. The ball  246  is located above the housing  214  partially within the vapor vent passage  220  and the second housing opening  242 B. The second housing opening  242 B may have an enlarged or tapered portion  244  for guiding and supporting the ball  246 . Vapor may exit the fuel tank through the first housing opening  242 A which includes an orifice limiting the flow. When the vapor pressure within the fuel tank reaches a sufficient level the ball  246  is lifted off the housing  214 , as shown. The vapor may exit through the first housing opening  242 A and the second housing opening  242 B around the sides of the ball  246 , as illustrated by arrows V. The tapered portion  244  assists in guiding the ball  246  in the proper position with respect to the housing  214 . As the vapor escapes the fuel tank the pressure within the fuel tank decreases and the ball  246  returns to the resting position on the housing  214 . Vapor may still exit the fuel tank through the first housing opening  242 A but will not exit through the second housing opening  242 B until the pressure within the fuel tank again increases to a level that will raise the ball  246  off the housing  214 . 
       FIG. 6  illustrates another embodiment of a valve assembly  310 . The valve assembly  310  has a housing  314 . A first housing portion  316  is located primarily within the fuel tank  312  and a second housing portion  318  is located primarily outside of the fuel tank  312 . The housing  314  also defines a vapor vent passage  320 , also referred to as a vent opening, which is in fluid communication with a vapor outlet  322 . The vapor outlet  322  leads to a vapor recovery canister (not shown) or other destination outside of the tank  312 . 
     The first housing portion  316  is inserted within a tank hole  324  in the fuel tank  312 . The housing  314  includes a flange  326  which is located outside of the fuel tank  312  to prevent the valve assembly  310  from passing entirely through the tank hole  324  and into the fuel tank  312 . The second housing portion  318  is sometimes referred to as the vapor recovery side of the housing  314 . 
     The housing  314  includes a carrier  328 . A membrane  338  is secured to the carrier  328  by weld, adhesive, heat sealing, insert molding, or other methods. One skilled in the art would know the appropriate attachment required for a particular membrane  338 . 
     The membrane  138  is illustrated in as a generally flat membrane. However, the membrane  138  may also be a cylinder, may be spirally wound, or may be pleated to increase the surface area of the membrane  138 . One skilled in the art would know the proper shape for a membrane  138  for a particular valve assembly  110  arrangement. 
     The carrier  328  and housing  314  defines a housing opening  348  through which vapor within the fuel tank  312  can vent through to the vapor vent passage  320 . The membrane  338  is secured to the carrier  328  and extends over the entire housing opening  348 . The membrane  338  is of a material that allows vapor to pass through the membrane  338  but prohibits liquid from passing through. 
     The carrier  328  includes at least one flow control feature  339 . In the embodiment shown, the flow control feature  339  is a restriction in the size of the housing opening  348  to control the amount of vapor that may exit the fuel tank  312  at one time. 
     Additionally the flow control feature  339  may include a soft shut off feature on the first housing portion  316 . The first housing portion  316 , in this instance, is often referred to as a dip tube. The first housing portion  316  extends downward within the fuel tank  312 . As is known to those skilled in the art the first housing portion  316  may provide an air pocket to control shut off of a fuel pump when filling the fuel tank. In the embodiment shown, the first housing portion  316  has a tapered edge  350  around at least a portion of the first housing portion  316 . Additionally, the first housing portion  316  defines a fuel shut off aperture  352 . The tapered edge  350  and the fuel shut off aperture  352  provide for restricted vapor flow as the fuel tank  312  is filled with fluid. Therefore, this will accommodate for sloshing as the fuel tank is filled, by minimizing the amount of liquid from the sloshing that reaches the membrane  338 . The tapered edge  350  and fuel shut off aperture  352  can be used together or individually to restrict vapor flow into the housing as the liquid level rises until the tapered edge  350  and the fuel shut off aperture  352  are completely submerged. 
     Alternatively to a dip tube, the flow control feature  339  may include a float located within the first housing portion  316  which may also be used to control fuel shut off at a fuel pump, as is known in the art. 
     While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.