Patent ID: 8075667

Claim:
A method of managing pressure in a fuel storage tank to prevent fugitive emissions, comprising the steps of: when the fuel storage tank is overpressurized: receiving a hydrocarbon air mixture from the fuel storage tank into an inlet port of a carbon canister containing hydrocarbon adsorbing activated carbon; adsorbing hydrocarbons from the hydrocarbon air mixture onto the carbon inside the carbon canister leaving a substantially cleansed air residual from the hydrocarbon air mixture; and controlling the venting of the substantially cleansed air through an outlet port of the carbon canister to vent the substantially cleansed air through the outlet port; and when the fuel storage tank is underpressurized: receiving outside air through the outlet port of the carbon canister; purging the hydrocarbons contained in the carbon in the carbon canister using the received outside air flowing through the outlet port of the carbon canister; and returning the purged hydrocarbons to the fuel storage tank.