Patent attributes
An underground fuel tank releases vapors depending upon air pressure. A vapor pressure management system has a canister for a vapor recovery system that connects with piping from an underground tank and has carbon therein along with appurtenant pipes and valves. When an ORVR vehicle refuels, the pressure lowers in an underground tank that draws air through the valves into the canister. After refueling an ORVR vehicle, environmental conditions generate hydrocarbon vapors. Barometric pressure drops and evaporated fuel during long refueling lulls produce hydrocarbon vapors at an increased pressure. Those hydrocarbon rich vapors then return to the canister of the system where the carbon binds the hydrocarbons while releasing air to the atmosphere. The refueling of the next ORVR vehicle draws in atmospheric air to purge the hydrocarbons retained in the canister of the system.
