Auxiliary vapor recovery device for fuel dispensing system

An auxiliary vapor recovery device for use with a fuel dispensing system comprising a dispensing apparatus for delivery of fuel from a storage tank system into a vehicle tank, a recovery apparatus for return of hydrocarbon vapor/air mixture displaced by fuel delivery to ullage space of the storage tank system, a piping manifold interconnecting the ullage space of storage tanks in the storage tank system, and a vent pipe terminating in a pressure relief vent valve adapted to open when vapor pressure in the ullage space reaches a predetermined maximum level,

• said auxiliary vapor recovery device comprising a vacuum pump,
• a canister defining a volume containing a substance adapted to remove molecules of hydrocarbon from hydrocarbon vapor/air mixture flowing through said canister, a recovery device conduit system comprising:
• a first conduit between said vacuum pump and the piping manifold from the ullage space of the fuel storage system, for flow of vapor from the ullage space into said vapor recovery device,
• a second conduit between said vacuum pump and the piping manifold from the ullage space of the fuel storage system, for flow of vapor from said vapor recovery device toward the ullage space,
• a third conduit for flow of vapor toward said canister,
• a fourth conduit between said vacuum pump and said canister for flow of vapor toward said vacuum pump, and
• a fifth conduit connected to the volume of said canister for release of air from said vapor recovery device,
• a solenoid valve system comprising a first solenoid valve and a second solenoid valve positioned in said recovery device conduit system, said solenoid valve system having a first, recovery condition for permitting flow of hydrocarbon vapor/air mixture from the ullage space, through said canister for removal of hydrocarbon vapor and release of air, a second, off condition for restricting flow of vapor in said recovery device conduit system and a third, stripping condition for establishing an increased vacuum condition within said canister for return of hydrocarbon vapor to the ullage space, and
• a solenoid valve system control apparatus adapted to cause said solenoid valve system to move among said first condition, said second condition and said third condition.