Abstract:
A valve assembly is provided that is suitable for use in a fuel fill line. The valve assembly may include a housing having a flange that surrounds the housing. A weld foot can be molded over at least a portion of the flange. A lip seal may be disposed between the flange and the weld foot. The lip seal includes a first lip and a second lip, and the first lip and the second lip may both be in contact with a surface on one of the flange and the weld foot.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of and claims the benefit of PCT Application No. PCT/US2013/031859, filed on Mar. 15, 2013, which claims the benefit of United States Provisional Application Serial No. 61/677,245, filed Jul. 30, 2012, the disclosures of which are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present teachings relate to valve seals, including a lip structure for a valve seal. 
       BACKGROUND 
       [0003]    Valves, such as inline check valves or other valves, may include sealing structures between two valve components to prevent leakage of fluid and/or vapor. In fuel tank applications, for example, the seal prevents fuel from leaking between layers or to the atmosphere. However, various conditions may weaken the sealing capabilities of the seal. For example, high internal pressures in the valve and/or a high differential between the pressures inside and outside the valve may cause leakage. Contamination, flash, or other debris on the sealing surface may also compromise the seal. 
       SUMMARY 
       [0004]    A valve assembly is provided that is suitable for use in a fuel fill line. The valve assembly may include a housing having a flange that surrounds the housing. A weld foot can be molded over at least a portion of the flange. A lip seal may be disposed between the flange and the weld foot. The lip seal includes a first lip and a second lip that may both be contact with a surface on one of the flange and the weld foot. 
         [0005]    Various aspects of the present teachings will become apparent to those skilled in the art from the following detailed description of the embodiments, when read in light of the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein: 
           [0007]      FIG. 1  is a schematic section view of a valve having a redundant lip seal according to one aspect of the teachings; 
           [0008]      FIG. 2  is a close-up schematic view of a portion of the valve in  FIG. 1 ; and 
           [0009]      FIG. 3  is a closer schematic view of a portion of the valve in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Reference will now be made in detail to embodiments of the present disclosure, examples of which are described herein and illustrated in the accompanying drawings. While the invention will be described in conjunction with embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0011]    The teachings herein illustrate a valve seal having improved sealing capabilities.  FIG. 1  is a representative or schematic section view of a valve  10  incorporating a lip seal  12  according to one aspect of the teachings. The lip seal  12  may be disposed between a flange  14  surrounding the valve  10  and a weld foot  16  designed or configured to be weldable onto a fuel tank. In an aspect of the teachings, the weld foot  16  may be overmolded onto a valve body  18 . The valve body  18  may include an interlock surface  20  that, in conjunction with the weld foot  16 , may create a labyrinth leak path that makes it difficult for fluid or vapor to escape the valve  10  and may also make the valve  10  resistant to delamination. 
         [0012]    As generally illustrated in  FIG. 2 , a seal ring  19  may be coupled to the lip seal  12  to provide more secure interlocking between the lip seal  12  and the weld foot  16 . The configuration may further improve leak-prevention robustness by, for example, preventing the lip seal  12  from being dislocated or deformed during an overmolding process. In an aspect of the teachings, the seal ring  19  may be comprised of metal. However, with embodiments, the seal ring  19  may also be comprised of other appropriate rigid materials, such as, for example, a plastic. Moreover, the seal ring  19  may also have a series of through holes, which for some embodiments or applications may mechanically hold the lip seal  12  in place comparatively better than a smooth surface and/or an adhesive between the seal ring  19  and the lip seal  12 . 
         [0013]    In embodiments, the lip seal  12  may have first and second lips  30 ,  32  that face different directions. In an aspect of the teachings, first and second lips  30 ,  32  may face opposite directions so that the lip seal  12  blocks fluid or vapor from moving past the lip seal  12  regardless of the direction of the pressure differential. This can better ensure a secure seal even when the valve  10  is tipped. The first and second lips  30 ,  32  can also provide a more robust labyrinth leak path and provide a backup seal in case debris compromises the sealing capabilities of one of the lips  30 ,  32 . When a weld foot  16  is formed onto the flange  14 , the lips  30 ,  32  deflect against the flange  14  as the lip seal  12  is compressed. In one aspect of the teachings, the flange  14  may include a shelf or step. With such a configuration, the seal ring  19  can be located against the shelf or step and the lips  30 ,  32  can deflect against the shelf or step to maintain uniform compression. 
         [0014]    Although the illustrated lip seal  12  shows the lips  30 ,  32  deflecting in different directions, the lips  30 ,  32  may be designed to deflect in the same direction without departing from the scope of the disclosure. The material used to manufacture the lip seal  12  can be, for example and without limitation, a low-permeability elastomer with a very high melting temperature so that the lip seal  12  can withstand the temperatures and pressures of an overmolding process. 
         [0015]    The valve  10  may, if desired, be manufactured using a unique overmolding process. In an embodiment, the overmolding process may contact the seal ring  19  at multiple places to hold the seal ring  19  in place more securely and perhaps also more evenly. 
         [0016]    Alternatively, or in addition, the overmolding process may incorporate a floating steel ring inside the tooling. In an embodiment, the steel ring may be supported by high biasing force springs, such as engine valve springs, against a plurality of stops in the mold. When molten, pressurized plastic enters the mold, the floating steel ring may act like a piston and may be compressed against the springs by the plastic. As the plastic cools, shrinks, and hardens, the springs can push back and compress the plastic to prevent voids from forming. 
         [0017]    As a result, the redundant lip seal structure  12  can prevent leaking regardless of the differential between the pressure inside the valve  10  versus outside the valve  10 . Moreover, the redundant lip seal  12  can provide extra sealing surfaces to improve its sealing capabilities, even if the lip seal  12  experiences contamination or flash on its sealing surface and/or high pressure operating conditions. 
         [0018]    It will be appreciated that the above teachings are merely exemplary in nature and is not intended to limit the present teachings, their application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present teachings as defined in the claims. Furthermore, the mixing and matching of features, elements and/or functions between various examples is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one example may be incorporated into another example as appropriate, unless described otherwise, above. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present teachings not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims.