Abstract: A method and apparatus for monitoring a fuel vapor recovery system to determine if a leak condition exists in either the vapor return passage in a fuel dispenser or a common vapor return pipe. An air-flow sensor (AFS) may be located in the common vapor return pipe for all of the dispensing points at a service station, or in each fuel dispenser and coupled to the dispensing points of the fuel dispenser. The AFS registers vapor flow recovered by a dispensing point(s) that is returned back to the storage tank. If the AFS measures vapor flow when such dispensing point(s) coupled to such AFS is not actively recovering vapor, this is indicative of a leak in such dispensing point(s). The leak condition is reported by a tank monitor or other reporting system so that appropriate measures can be taken.

Abstract: A system and method for removing, compressing, and storing excess air and vapors from a fuel dispensing facility fuel storage containment system during periods of over-pressurization without venting or processing the excess air and vapors. The stored air and vapors are subsequently returned back to the containment system during periods of under-pressurization that typically occur diurnally during periods of high fueling activity. The system may be used to compliment an ORVR compatible dispensing system that typically encounters over-pressurization problems when low or no refueling activity is occurring.

Abstract: A method and apparatus for monitoring and determining fuel vapor recovery performance is disclosed. The dispensing of liquid fuel into a tank by a conventional gas pump nozzle naturally displaces a mixture of air and fuel ullage vapor in the tank. These displaced vapors may be recovered at the dispensing point nozzle by a vapor recovery system. A properly functioning vapor recovery system recovers approximately one unit volume of vapor for every unit volume of dispensed liquid fuel. The ratio of recovered vapor to dispensed fuel is termed the A/L ratio, which should ideally be approximately equal to one (1). The A/L ratio, and thus the proper functioning of the vapor recovery system, may be determined by measuring liquid fuel flow and return vapor flow (using a vapor flow sensor) on a nozzle-by-nozzle basis. The disclosed methods and apparatus provide for the determination of A/L ratios for individual nozzles using a reduced number of vapor flow sensors.

Abstract: A method and apparatus for monitoring and determining fuel vapor recovery performance is disclosed. The dispensing of liquid fuel into a tank by a conventional gas pump nozzle naturally displaces a mixture of air and fuel ullage vapor in the tank. These displaced vapors may be recovered at the dispensing point nozzle by a vapor recovery system. A properly functioning vapor recovery system recovers approximately one unit volume of vapor for every unit volume of dispensed liquid fuel. The ratio of recovered vapor to dispensed fuel is termed the A/L ratio, which should ideally be approximately equal to one (1). The A/L ratio, and thus the proper functioning of the vapor recovery system, may be determined by measuring liquid fuel flow and return vapor flow (using a vapor flow sensor) on a nozzle-by-nozzle basis. The disclosed methods and apparatus provide for the determination of A/L ratios for individual nozzles using a reduced number of vapor flow sensors.

Abstract: A method and apparatus for monitoring and determining fuel vapor recovery performance is disclosed. The dispensing of liquid fuel into a tank by a conventional gas pump nozzle naturally displaces a mixture of air and fuel ullage vapor in the tank. These displaced vapors may be recovered at the dispensing point nozzle by a vapor recovery system. A properly functioning vapor recovery system recovers approximately one unit volume of vapor for every unit volume of dispensed liquid fuel. The ratio of recovered vapor to dispensed fuel is termed the A/L ratio, which should ideally be approximately equal to one (1). The A/L ratio, and thus the proper functioning of the vapor recovery system, may be determined by measuring liquid fuel flow and return vapor flow (using a vapor flow sensor) on a nozzle-by-nozzle basis. The disclosed methods and apparatus provide for the determination of A/L ratios for individual nozzles using a reduced number of vapor flow sensors.

Abstract: A method and apparatus for monitoring and determining fuel vapor recovery performance is disclosed. The dispensing of liquid fuel into a tank by a conventional gas pump nozzle naturally displaces a mixture of air and fuel ullage vapor in the tank. These displaced vapors may be recovered at the dispensing point nozzle by a vapor recovery system. A properly functioning vapor recovery system recovers approximately one unit volume of vapor for every unit volume of dispensed liquid fuel. The ratio of recovered vapor to dispensed fuel is termed the A/L ratio, which should ideally be approximately equal to one (1). The A/L ratio, and thus the proper functioning of the vapor recovery system, may be determined by measuring liquid fuel flow and return vapor flow (using a vapor flow sensor) on a nozzle-by-nozzle basis. The disclosed methods and apparatus provide for the determination of A/L ratios for individual nozzles using a reduced number of vapor flow sensors.

Abstract: An apparatus and method are provided for calibrating a liquid storage tank. The apparatus includes a sensor disposed within the tank for sensing the liquid levels in the tank and one or more metering devices for measuring the amount of liquid dispensed into or out of the tank. A processor is also provided which is capable of determining the volume in the tank as well as the amount of liquid dispensed into or out of the tank based on liquid level measurements obtained during idle periods following dispensing periods. The processor is programmed with an algorithm which employs a mathematical function which relates either the volume of the liquid or the change in volume of the liquid per unit of associated height change of the liquid in the tank as a function of the height of the liquid in the tank and a number of calibration parameters which include the length, diameter, end shape, and tilt of the tank as well as the offset of the sensor from the bottom of the tank.

Abstract: An apparatus and method are provided for calibrating manifolded liquid storage tanks. The apparatus includes sensors disposed within the tanks for sensing the liquid levels in each of the tanks and a metering device for measuring the amount of liquid dispensed into or out of the storage tanks. A processor is also provided which determines the amount of liquid dispensed from each tank based on liquid level measurements obtained during idle periods following dispensing periods. Once this information is obtained, single tank calibration techniques are employed. An alternate combined tank calibration can also be used. This method does not separate out the amount of liquid dispensed from each tank, but rather utilizes the combined amount dispensed. From this simpler, but less accurate method, an "equivalent" combined tank chart or combined mathematical formula may be generated using the metered amounts and a combined height amount. Heights from the two tanks may be simply averaged.

Abstract: A liquid level measuring device has an outer capacitance tube, an imperforate glass tube coaxially within the outer tube defining a capacitor annulus between them, and an inner capacitor sleeve coaxially within the glass tube and having separate longitudinally extending sleeve sections. The separate sleeve sections cooperate with the outer capacitance tube to form a plurality of capacitor sections each having a separately measurable value which varies between dry minimum and submerged maximum.

Abstract: A liquid level measuring system for the underground fuel storage tanks of a fuel dispensing station having a multiple segment capacitance probe in each storage tank and a microcomputer for periodically measuring the capacitance of each segment of each probe and calculating the level and volume of fuel in each tank using capacitance and volume calibration constants automatically updated by the microcomputer from the measured capacitance data and from fuel delivery data automatically fed to the microcomputer.