Fueling system vapor recovery and containment performance monitor and method of operation thereof

• US 7,975,528 B2
• Filed: 02/08/2010
• Issued: 07/12/2011
• Est. Priority Date: 11/30/1999
• Status: Expired due to Term

• Current Assignee: Veeder-Root Co (Vontier Corp.)
• Original Assignee: Veeder-Root Co (Vontier Corp.)
• Inventors: Hart, Robert P.
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): Frank; Rodney T
• Application Number:
  US12/702,107
• Publication Number:
  US 20100132436A1
• Time in Patent Office: 519 Days
• Field of Search: 73/40
• US Class Current: 73/40
• CPC Class Codes: B67D 7/0486 Pumps driven in response to electric signals indicative of pressure, temperature or liquid flow
• CPC Class Codes: B67D 7/0496 Performance test devices therefor
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: F02M 25/0872 Details of the fuel vapour pipes or conduits
• CPC Class Codes: G01M 3/02 by using fluid or vacuum
• CPC Class Codes: G01M 3/26 by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors

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.

Claims

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, 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.

2. 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 storage system comprises a fuel storage tank, comprising:

a pressure sensor operatively connected to the fuel storage system to measure pressure in the fuel storage system; and

a monitor operatively connected to the pressure sensor, wherein the monitor is adapted to;

monitor the pressure in the fuel storage system over a period of time;

estimate a pressure rate of change during the period of time;

monitor ullage volume of the fuel storage tank during the period of time; and

relate the estimated pressure rate of change to a rate of change of a predetermined parameter of the fuel storage system based on a predetermined pressure of the fuel storage system and the monitored ullage volume.

3. The system as in claim 2, wherein the predetermined parameter is vapor leak rate.

4. A method 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 storage system comprises a fuel storage tank, comprising the steps of:

measuring pressure in the fuel storage system over a period of time;

estimating a pressure rate of change during the period of time;

monitoring ullage volume of the fuel storage tank during the period of time; and

relating the estimated pressure rate of change to a rate of change of a predetermined parameter of the fuel storage system based on a predetermined pressure of the fuel storage system and the monitored ullage volume.

5. The method as in claim 4, wherein the predetermined parameter is vapor leak rate.