Patent ID: 8381775

Claim:
A method of conserving fuel vapor in a liquid fuel dispensing system without fuel vapor recovery or with fuel vapor recovery only during transfer of fuel into fuel storage tanks, the system comprising one or more liquid fuel storage tanks connected to one or more dispensers for delivering liquid fuel to vehicle fuel tanks, said method comprising: connecting ullage space of the one or more liquid fuel storage tanks to a bladder within a vapor conservation tank; connecting ullage space of a liquid fuel delivery vehicle to air space of the vapor conservation tank containing the bladder, external of the bladder; delivering liquid fuel from the liquid fuel delivery vehicle into the one or more liquid fuel Storage tanks, the liquid fuel displacing fuel vapor from the one or more liquid fuel storage tanks; delivering the fuel vapor displaced from the one or more liquid fuel storage tanks by the liquid fuel into the bladder, the delivered fuel vapor inflating the bladder and displacing air from the air space of the vapor conservation tank external of the bladder; delivering at least a portion of the air displaced from the air space of the vapor conservation tank into the ullage space of the liquid fuel delivery vehicle, the displaced air replacing a volume of the liquid fuel delivered from the liquid fuel delivery vehicle into the liquid fuel storage tanks; and, thereafter, over time, delivering fuel vapor from the bladder of the vapor conservation tank into the ullage space of the one or more liquid fuel storage tanks, replacing the volume of liquid fuel delivered from the one or more liquid fuel storage tanks into vehicle fuel tanks.