Patent ID: 7063226

Claim:
A fuel tank assembly comprising: a wall for enclosing a fluid; said wall having an upper wall and an inwardly flanged lip extending downwardly from said upper wall into said fuel tank forming an opening extending through a portion of said wall and defining a first sealing surface along the circumferential periphery of said lip; a removable lid for closing said opening in said wall, said lid having an outer peripheral part defining a second sealing surface along the circumferential periphery thereof facing said first sealing surface when said lid is seated in said opening; first and second spaced apart radial grooves formed in at least one of said first and second sealing surfaces; first and second sealing rings seated in said first and second grooves respectively for sealing engagement between said first and second sealing surfaces when said lid is closed against said opening; a sealing gap formed between said first sealing surface and the part of said second sealing surface extending between said spaced apart radial grooves for limiting the contact surface area of fuel vapors with said second sealing ring and thereby increase the permeation resistance of said sealing engagement between said lid and said opening; and a reinforcement member including a planar portion fixedly secured to the inside of said upper wall and a shoulder portion extending downwardly from said planar portion forming a surrounding shoulder which supports said circumferential periphery of said inwardly flanged lip defining said opening for conically supporting said lip against the sealing forces between said first and second sealing surfaces from said lid closing against said opening.