Abstract: A vent control valve for controlling fuel vapor flow from a fuel tank to a vapor storage canister during fuel supply to the fuel tank. The vent control valve is fixedly attached to a fuel filler tube and formed therein with first and second chambers. The first and second chambers are located side by side on an immaginary plane along the fuel filler tube. The first and second chambers are communicated respectively with the fuel tank and the vapor storage canister. A valve mechanism is provided between the first and second chambers and adapted to cause the first and second chambers to communicate with each other so as to allow fuel vapor in the fuel tank to flow into the vapor storage canister, when opened. The valve mechanism is opened when a fuel supply gun is inserted into the fuel filler tube to supply fuel into the fuel tank.

Abstract: A liquefied gas overcharge prevention device provided with a safety valve. The overcharge prevention system comprises, in combination, a conventional pressurized gas tank charging valve having a liquid level responsive gas inlet valve mechanism, a first relief valve for regulating pressure within the tank and a second relief valve for regulating back pressure within the charging valve.