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

• US 6,964,283 B2
• Filed: 09/07/2004
• Issued: 11/15/2005
• 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): MAUST, TIMOTHY LEWIS
• Application Number:
  US10/935,024
• Publication Number:
  US 20050034778A1
• Time in Patent Office: 434 Days
• Field of Search: 141 4- 8, 141/45, 141/59, 141/83, 141/94, 141/98, 137/583, 137/587, 137/588, 137/589, 73/405.R, 73/491
• US Class Current: 141/8
• 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 one or more fuel dispensing units, comprising:

a pressure sensor operatively connected to the fuel storage system or pipeline system coupled to the fuel storage system to measure the pressure level in the fuel storage system;

a monitor operatively connected to said pressure sensor; and

a vapor processor operatively connected to the fuel storage system wherein said vapor processor draws a negative pressure in the fuel storage system when the fuel storage system is not adequately negative;

said monitor monitors said pressure level in the fuel storage system using readings from said pressure sensor to determine if the fuel storage system contains a leak.

2. The system of claim 1, wherein said pressure sensor is located in a location that is comprised of the group consisting of a fuel storage tank, a fuel storage tank vapor space, a fuel storage tank vent pipe, a pipeline system, and a common vapor return pipeline.

3. The system of claim 1, wherein said monitor monitors said pressure level in the fuel storage system only when all of the one or more fuel dispensing units are idle.

4. The system of claim 1, wherein said vapor processor draws a negative pressure in the fuel storage system until said pressure level is adequately negative.

5. The system of claim 4, wherein said adequately negative pressure is between −

2 inches w.c. and −

3 inches w.c.

6. The system of claim 4, wherein said monitor aborts monitoring said pressure level in the fuel storage system if one or more of the one or more fuel dispensing units becomes active.

7. The system of claim 1, wherein said monitor determines if the fuel storage system is adequately tight by monitoring the decay of said pressure level over time.

8. The system of claim 7, wherein said monitor determines if said decay of said pressure level over time exceeds a threshold level.

9. The system of claim 8, wherein said monitor indicates a fail condition if said decay of said pressure level over time exceeds said threshold level.

10. The system of claim 8, wherein said monitor indicates a pass condition if said decay of said pressure level over time does not exceed said threshold level.

11. The system of claim 8, wherein said threshold level is a percectage of the negative pressure level generated by said vapor processor in the fuel storage system.

12. The system of claim 1, further comprising an air flow sensor located in the fuel storage system and operatively connected to said monitor, wherein said monitor determines if the fuel storage system is tight based on readings from said air flow sensor.

13. The system of claim 12, wherein said monitor determines the location of a leak in the fuel storage system based on the location of said air flow sensor.

14. The system of claim 12, wherein said monitor determines the location of a leak in the fuel storage system based on the air flow direction measured by said air flow sensor.

15. The system of claim 12, wherein said air flow sensor is shared among a plurality of fuel storage tanks in the fuel storage system that share a common vapor space.

16. The system of claim 1, wherein said monitor determines if the fuel storage system is adequately tight by monitoring if the pressure level degrades to a level that is a percentage of the negative pressure level generated by said vapor processor in the fuel storage system.

17. A method of monitoring vapor content in a liquid fuel dispensing facility having a fuel storage system that provides fuel for dispensing by one or more fuel dispensing units, comprising the steps of:

activating a vapor processor to draw a negative pressure the fuel storage system when the pressure level in the fuel storage system is not adequately negative;

monitoring said pressure level in the fuel storage system using a pressure sensor operatively connected to the fuel storage system or pipeline system coupled to the fuel storage system; and

determining if the fuel storage system contains a leak based on the change in said pressure level in said step of monitoring.

18. The method of claim 17, wherein said pressure sensor is located in a location that is comprised of the group consisting of a fuel storage tank, a fuel storage tank vapor space, a hid storage tank vent pipe, a pipeline system, and a common vapor return pipeline.

19. The method of claim 17, wherein said step of monitoring is only performed when all of the one or more fuel dispensing units are idle.

20. The method of claim 17, further comprising drawing a negative pressure in the fuel storage system until said pressure level is adequately negative.

21. The method of claim 20, wherein said adequately negative pressure is between −

2 inches w.c. and −

3 inches w.c.

22. The method of claim 20, further comprising aborting said step of monitoring if the one or more of the one or more fuel dispensing units becomes active.

23. The method of claim 17, wherein said step of monitoring said pressure level comprises monitoring the decay of said pressure level over time.

24. The method of claim 23, wherein said step of monitoring comprises determining if said decay of said pressure level over exceeds a threshold level.

25. The method of claim 23, wherein said step of monitoring comprises determining if said decay of said pressure level over time does not exceed a threshold level.

26. The method of claim 25, further comprising indicating a fail condition if said decay of said pressure level over time exceeds said threshold level.

27. The method of claim 25, further comprising indicating a pass condition if said decay of said pressure level over time does not exceed said threshold level.

28. The method of claim 24, wherein said threshold level is a percentage of the negative pressure level generated by said vapor processor in the fuel storage system.

29. The method of claim 17, further comprising sensing vapor flow in the fuel storage system using an air flow sensor to determine if fuel storage system is tight.

30. The method of claim 29, further comprising determining the location of a leak in the fuel storage system based on the location of said air flow sensor.

31. The method of claim 29, further comprising monitoring the location of a leak in the fuel storage system based on the air flow direction measured by said air flow sensor.

32. The method of claim 17, wherein said step of monitoring comprises determining if said pressure level degrades to a level that is a percentage of the negative pressure level generated by said vapor processor in the fuel storage system.