FUELING SYSTEM VAPOR RECOVERY AND CONTAINMENT PERFORMANCE MONITOR AND METHOD OF OPERATION THEREOF
First Claim
1. A system for monitoring vapor containment in a liquid fuel dispensing facility having a fuel storage system that provides fuel for dispensing by at least one fuel dispensing unit, wherein the fuel dispensing facility monitors fuel level in the fuel storage system and determines ullage volume in the fuel storage system based on the fuel level, comprising:
- a pressure sensor operatively connected to the fuel storage system to measure pressure in the fuel storage system;
a monitor operatively connected to the pressure sensor that receives pressure data from the pressure sensor and the ullage volume,determines multiple rates of change of pressure at respective actual pressures based on the pressure data received over time,estimates a test rate of change of pressure at a predetermined test pressure based on the multiple rates of change of pressure, andadjusts the multiple rates of change of pressure for ullage volume so that the test rate of change of pressure corresponds to a predetermined vapor containment leak standard.
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Accused Products
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. The disclosed methods and apparatus also provide for the determination of fuel dispensing system vapor containment integrity, and the differentiation of true vapor recovery failures as opposed to false failures resulting from the refueling of vehicles provided with onboard vapor recovery systems.
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Citations
1 Claim
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1. A system for monitoring vapor containment in a liquid fuel dispensing facility having a fuel storage system that provides fuel for dispensing by at least one fuel dispensing unit, wherein the fuel dispensing facility monitors fuel level in the fuel storage system and determines ullage volume in the fuel storage system based on the fuel level, comprising:
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a pressure sensor operatively connected to the fuel storage system to measure pressure in the fuel storage system; a monitor operatively connected to the pressure sensor that receives pressure data from the pressure sensor and the ullage volume, determines multiple rates of change of pressure at respective actual pressures based on the pressure data received over time, estimates a test rate of change of pressure at a predetermined test pressure based on the multiple rates of change of pressure, and adjusts the multiple rates of change of pressure for ullage volume so that the test rate of change of pressure corresponds to a predetermined vapor containment leak standard.
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Specification