Method and apparatus for monitoring operational performance of fluid storage systems

• US 6,401,045 B1
• Filed: 05/22/1998
• Issued: 06/04/2002
• Est. Priority Date: 06/04/1996
• Status: Expired due to Term

• Current Assignee: Warren Rogers Associates, Inc.
• Original Assignee: Warren Rogers Associates, Inc.
• Inventors: Rogers, Warren F., Collins, John R., Jones, Jillanne B.
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): TSAI, CAROL S W
• Application Number:
  US09/083,732
• Time in Patent Office: 1,474 Days
• Field of Search: 702/45, 702/50, 702/51, 702/55, 702/100, 702/114, 702/156, 702/177, 702/179, 702/182-185, 702/187, 702/188, 702/196, 702/FOR.103, 702/FOR.104, 702/FOR.123, 702/FOR.124, 702/FOR.127, 702/FOR.128, 702/FOR.134, 702/FOR.135, 702/FOR.139, 702/FOR.170, 702/FOR.171, 137/212, 141/86, 222/1, 222/52, 222/55, 222/58, 222/40, 73/405.R, 73/405.A, 700/240, 700/281
• US Class Current: 702/51
• CPC Class Codes: G01F 23/802 Particular electronic circuits for digital processing equipment
• CPC Class Codes: G01F 23/804 containing circuits handling parameters other than liquid level

Abstract

The operational performance of a fluid storage and dispensing system is monitored by measurement apparatus which measures a volume associated with the system. A plurality of measurement data is collected from the measurement apparatus in a form readable by a computer and is stored in a compressed matrix format in a computer memory. The compressed matrix format is statistically analyzed to determine operational monitoring information regarding the system. The temperature of the fluid may also be measured for calculating the volume associated with the system. The operational performance and volume of the fluid storage system may be precisely monitored without requiring presumptions as to the accuracy of the measurement apparatus.

Claims

1. A method of monitoring a fluid storage and dispensing system including a tank for storing fluid and at least one measuring device for providing indications of status of the fluid, the method comprising:

collecting data from the at least one measuring device at a plurality of times, the collected data including data representative of a device-indicated volume of the fluid in the tank;

calculating an analytic tank fluid volume at each of the plurality of times;

calculating an expected volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times;

calculating an actual volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times; and

providing an indication of a pattern of the relationship between the expected volume difference and the actual volume difference at the plurality of times.

2. The method of claim 1 wherein the relationship between the expected volume difference and the actual volume difference has a nonrandom pattern indicative of a loss of fluid from the tank.

3. The method of claim 1 wherein the collecting step includes collecting data indicative of a level of the fluid in the tank and the analytic tank fluid volume is a function of the level of the fluid in the tank.

4. The method of claim 1 wherein the expected volume difference calculating step includes calculating an expected analytic volume based on at least one tolerance value of the at least one measuring device.

5. The method of claim 1 wherein the collecting step includes providing computer readable data indicative of amounts of fluid delivered to the tank, amounts of fluid removed from the tank, and levels of fluid in the tank, the method further comprising storing the computer readable data in a compressed matrix format in a computer memory, the compressed matrix being a product of a data matrix of the computer readable data and a transpose of the data matrix.

6. The method of claim 5 wherein the storing step comprises adding partial products of each of a plurality of partitions of the data matrix with the transpose of each partition.

7. The method of claim 5 wherein the collecting step provides data indicative of cumulative fluid delivery to the tank and removal from the tank.

9. The method of claim 1 wherein the collecting step includes collecting data indicative of the temperature of the fluid at each of the plurality of times and wherein the step of calculating the analytic tank fluid volume incorporates the temperature data.

10. The method of claim 1 further comprising determining whether fluid is leaking from the tank based on the indication of the pattern of the relationship between the expected volume difference and the actual volume difference.

11. The method of claim 10 wherein the providing step further provides an indication that fluid is leaking from the tank.

8. A method of monitoring a fluid storage and dispensing system including a tank for storing fluid and at least one measuring device for providing indications of status of the fluid, the method comprising:

collecting data from the at least one measuring device at a plurality of times, the collected data including data representative of a device-indicated volume of the fluid in the tank;

calculating an analytic tank fluid volume at each of the plurality of times;

calculating an expected volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times;

calculating an actual volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times;

providing an indication of a pattern of the relationship between the expected volume difference and the actual volume difference at the plurality of times;

estimating a differential of a volume function of the volume of the fluid, the volume function being a function of the level of the fluid in the tank; and

integrating the differential of the volume function to yield the volume function;

wherein the calculating analytic tank fluid volume step includes evaluating the volume function for a desired fluid level.

12. A fluid storage and dispensing system comprising:

a tank for storing the fluid;

a plurality of measuring devices for providing, at a plurality of times, data indicative of fluid status including data representative of a device-indicated volume of the fluid in the tank;

a processor for receiving the data from the measuring devices, calculating an analytic tank fluid volume at each of the plurality of times, calculating an expected volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times, calculating an actual volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times, and providing an indication of a pattern of the relationship between the expected volume difference and the actual volume difference at the plurality of times.

13. The system of claim 12 wherein the relationship between the expected volume difference and the actual volume difference has a nonrandom pattern indicative of a loss of fluid from the tank.

14. The system of claim 12 wherein the processor reduces the amount of received data by storing the data in a compressed data matrix format, the compressed data matrix being a product of a data matrix and a transpose of the data matrix.

15. The system of claim 12 wherein the measuring devices include a volume level indicator and a dispensing apparatus.

16. The system of claim 12 wherein the volume level indicator comprises a magnetostrictive tank probe.

17. The system of claim 12 wherein the dispensing apparatus comprises a totalizer.

18. The system of claim 12 further comprising a leak indicator coupled to the processor for providing a leak indication if the relationship between the actual volume variance and the expected variance has a continuously nonrandom pattern.

19. A fluid storage and dispensing system comprising:

a tank for storing the fluid;

a plurality of measuring devices for providing, at a plurality of times, data indicative of fluid status including data representative of a device-indicated volume of the fluid in the tank;

a processor for receiving the data from the measuring devices, calculating an analytic tank fluid volume at each of the plurality of times, calculating an expected volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times, calculating an actual volume difference between the analytic tank fluid volume and the device-indicated volume at each of the plurality of times, and providing an indication of a pattern of the relationship between the expected volume difference and the actual volume difference at the plurality of times; and

a one-time volume change indicator coupled to the processor for providing an indication of a one-time volume change if the processor determines that a difference between the actual volume difference and the expected volume difference exceeds a predetermined amount.

20. A computer program product residing on a computer readable medium for use with a fluid storage and dispensing system including a fluid storage tank and at least one status device for providing indications of fluid status, the computer program product comprising instructions for causing a computer to

receive at least a portion of the indications of fluid status at a plurality of times and determine a computed tank fluid volume;

receive the portion of the indications of fluid status at each of the plurality of times and determine a measured tank fluid volume as indicated by the at least one measuring device;

determine an expected volume variance between the computed tank fluid volume and the measured tank fluid volume;

determine an actual volume variance between the computed tank fluid volume and the measured tank fluid volume; and

determine a pattern in the relationship between the actual volume variance and the expected volume variance.

21. The computer program product of claim 20 wherein the instructions for causing the computer to determine a pattern in the relationship between the actual volume variance and the expected volume variance cause the computer to determine a nonrandom pattern indicative of a loss of fluid from the tank.

22. The computer program product of claim 20 wherein the instructions for causing the computer to determine a pattern further cause the computer to provide a leak indication if the relationship between the actual volume variance and the expected variance has a continuously nonrandom pattern.

23. The computer program product of claim 20 wherein the indications of fluid status are stored as data, the computer program product further comprising instructions for causing the computer to reduce the amount of data stored.

24. The computer program product of claim 23 wherein the instructions for causing the computer to reduce the amount of data stored cause the computer to determine a product of a data matrix containing the data and a transpose of the data matrix.

25. The computer program product of claim 24 wherein the instructions for causing the computer to reduce the amount of data stored cause the computer to determine the product by adding partial products of each of a plurality of partitions of the data matrix with the transpose of each partition.

26. The computer program product of claim 20 further comprising instructions for causing the computer to determine the tank fluid volume as a function of a level of the tank-fluid using at least a portion of the indications of fluid status.

27. The computer program product of claim 26 wherein the instructions for causing the computer to determine the tank fluid volume cause the computer to determine coefficients of a polynomial.

29. The computer program product of claim 20 further comprising instructions for causing the computer to provide an indication that the actual volume variance and the expected volume variance differ by more than a predetermined amount.

28. A computer program product residing on a computer readable medium for use with a fluid storage and dispensing system including a fluid storage tank and at least one status device for providing indications of fluid status, the computer program product comprising instructions for causing a computer to

receive at least a portion of the indications of fluid status at a plurality of times and determine a computed tank fluid volume;

receive the portion of the indications of fluid status at each of the plurality of times and determine a measured tank fluid volume as indicated by the at least one measuring device;

determine the tank fluid volume as a function of a level of the tank fluid using at least a portion of the indications of fluid status;

determine an expected volume variance between the computed tank fluid volume and the measured tank fluid volume;

determine an actual volume variance between the computed tank fluid volume and the measured tank fluid volume; and

determine a pattern in the relationship between the actual volume variance and the expected volume variance;

wherein the instructions for causing the computer to determine the tank fluid volume cause the computer to estimate a differential of the volume function and integrate the estimated differential to determine the tank fluid volume.