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 detecting the dry-run operation of a submersible fuel pump operating in a network of fuel pumps is disclosed in which the pump controller is able to switch itself off upon detection of a dry-run condition. After shutting itself off, the pump controller can request assistance from another pump in the pump network. When fuel is added to the tank, the fuel pump controller will detect the presence of the fuel and reactivate the pump.