The present teachings relate to valve seals, and more particularly to a closure surface for a fuel vapor valve.
Fuel vapor valves of the float-operated type operate by closing a vent port in a fuel tank when the fuel level in the tank reaches a set or predetermined level. These valves may include a relatively thin elastomeric seal that can engage a closure surface of the vent port to close the valve. The valve port may have a relatively large circumference to provide the desired vapor flow at low vapor pressures. As a result, a relatively low closing force can be used to seal the elastomeric seal against the closure surface. When the fuel level in the tank drops below the predetermined level, the valve is configured to reopen and release fuel vapor through the valve port.
However, the quality of the seal may also be affected if the elastomeric seal sticks to the closure surface before the seal squarely orients itself relative to the closure surface. Further, increased vapor pressure in the fuel tank along with the relatively large circumference of the valve port can cause the elastomeric seal to remain engaged against the closure surface, thereby preventing the valve from opening. In other words, the valve sticks and remains closed in situations where it is desired for the valve to be open.
Thus, it is desirable to provide a closure surface for a valve port to allow a elastomeric seal to slide into place during engagement and seal squarely against the closure surface. It is also desirable to provide a closure surface that traps liquid for lubrication of the elastomeric seal but does not provide a leak path. It is also desirable to provide a closure surface that allows the elastomeric seal to reopen with a low peel-away force.
A valve assembly is provided for venting pressure in a fuel tank. The valve assembly includes a float member that is movable between a first position and a second position. A flexible seal is supported on the float member. The valve assembly also includes a valve port that defines an orifice and a closure surface surrounding the orifice. The closure surface includes textured features that are configured to engage a surface of the seal when the float member is in the second position.
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.
Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:
Reference will now be made in detail with respect to embodiments of the present teachings, examples of which are described herein and illustrated in the accompanying drawings. While concepts will be described in conjunction with embodiments, it will be understood that the invention is not intended to limit the specific disclosures associated with the 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.
Valves, such as inline check valves or other valves, may include an elastomeric seal that selectively engages with a valve closure surface to open and close the valve. To ensure low leakage, the seal should close and remain closed with the application of a very low closure force, for example and without limitation, on the order of 5 to 10 grams of force.
In one aspect of the teachings, the seal 12 can be disposed on top of a flapper 20. In embodiments, the flapper 20 may be coupled to the float 18 such that the flapper 20 may position itself for a secure connection between the seal 12 and the closure surface 14. The example illustrated in the figures shows a gimbaled connection between the flapper 20 and the float 18; however, other forms of connection can be used without departing from the scope of the teachings.
To improve the sealing properties of the interface 10, the closure surface 14 may include a plurality of features 22 that create a texture on the closure surface 14. The features 22 can be designed to allow the seal 12 to slide into place and seal squarely against the closure surface 14. In an embodiment, the features 22 may be smooth, microstructured raised features and/or pits arranged in a pattern , which may be a regular pattern. The features 22 may be formed as a microscopic surface texture on the closure surface 14.
When the seal 12 contacts the closure surface 14, the features 22 can trap liquid to lubricate the interface 10 while also blocking a leak path, thereby creating a low- or no-leak interface 10. The features 22 may also allow the seal 12 and the closure surface 14 to close securely at any random orientation while still allowing the seal 12 to peel away from the closure surface 14 with relatively low force. More particularly, the features 22 may allow excess fluid, which can cause the seal 12 to stick, to drain away from the interface 10.
To further improve sealing, the closure surface 14 may include a tip 24 that is slightly tapered or conical and has a smooth radius that blends toward the orifice 16, such as generally illustrated in the figures. When the seal 12 contacts the tip 24, particularly at a transition 26 from the conical portion to the radius, the seal 12 may deform slightly against the tip 24, such as generally shown in
In another aspect of the present teachings, for example as generally illustrated in
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.
This application is a continuation of and claims the benefit of PCT Application No. PCT/US2013/031479, filed on Mar. 14, 2013, which claims the benefit of U.S. Provisional Application Ser. No. 61/670,788, filed Jul. 12, 2012, the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61670788 | Jul 2012 | US |
Number | Date | Country | |
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Parent | PCT/US2013/031479 | Mar 2013 | US |
Child | 14580396 | US |