US Patent 7703629 Bi-laterally cleansing fuel cap

A fuel cap having a cap member with an internal chamber and a downward extending hollow tube in open communication with the internal chamber and in sealing communication with a lower hub bore; vents on side walls of the internal chamber; an absorption media inside the internal chamber below the vents and above the hollow tube; a hub rotatably and slidably connected to the cap member with the hub having a lower hub bore into which the hollow tube is translatable for releasing vapors from the fuel tank as necessary before re-fueling whereby the vapors pass through the absorption media where they are cleansed before being release out the vents.