Leak detection in fluid conducting conduit

• US 9,037,422 B2
• Filed: 08/13/2012
• Issued: 05/19/2015
• Est. Priority Date: 08/13/2012
• Status: Active Grant

• Current Assignee: Schneider Electric Software, LLC (Schneider Electric SE)
• Original Assignee: Invensys Systems Incorporated (Invensys PLC)
• Inventors: McHugh, Robert Terrence, Jacob, Errol F., Wilbers, Daniel Matthew
• Primary Examiner(s): Breene, John
• Assistant Examiner(s): Dinh, Lynda
• Application Number:
  US13/584,503
• Publication Number:
  US 20140046605A1
• Time in Patent Office: 1,009 Days
• Field of Search: 702/51
• US Class Current: 702/51
• CPC Class Codes: G01M 3/2815 using pressure measurements
• CPC Class Codes: G01M 3/3254 using a flow detector G01M3/3245, G01M3/3272 take precedence
• CPC Class Codes: G01M 3/3263 using a differential pressure detector G01M3/3245, G01M3/3272 take precedence
• CPC Class Codes: G01M 3/3272 for verifying the internal pressure of closed containers

Abstract

A method for detecting a leak in a fluid conducting conduit is disclosed. Inlet and outlet flowrates are measured for calculating a time derivative of average temperature of the fluid flowing in the fluid conducting conduit. A predicted difference in flowrate between a flowrate of fluid in the fluid conducting conduit adjacent the inlet and a flowrate of fluid in the fluid conducting conduit adjacent the outlet is calculated based on the calculated time derivative of the average temperature of the fluid flowing in the fluid conducting conduit. The predicted difference in flowrate is compared to a difference between the measured inlet flowrate and the measured outlet flowrate to determine whether a leak exists in the fluid conducting conduit.

Claims

1. A method for detecting a leak in a fluid conducting conduit, the method comprising:

measuring an inlet flowrate of fluid flowing in the fluid conducting conduit using a first flowrate sensor, said first flowrate sensor being positioned adjacent an inlet of the fluid conducting conduit;

measuring an outlet flowrate of fluid flowing in the fluid conducting conduit using a second flowrate sensor, said second flowrate sensor being positioned adjacent an outlet of the fluid conducting conduit;

generating a time series of expected average temperature of the fluid flowing in the fluid conducting conduit based on the measured inlet flowrate and the measured outlet flowrate;

calculating a time derivative of average temperature of the fluid flowing in the fluid conducting conduit based on the measured inlet flowrate and the measured outlet flowrate, wherein said calculating a time derivative of average temperature of the fluid comprises analyzing a time series of expected average temperature of the fluid and generating said calculated time derivative of average temperature of the fluid based thereon;

calculating a predicted difference in flowrate between a flowrate of fluid in the fluid conducting conduit adjacent the inlet and a flowrate of fluid in the fluid conducting conduit adjacent the outlet based on the calculated time derivative of the average temperature of the fluid flowing in the fluid conducting conduit;

comparing the predicted difference in flowrate to a difference between the measured inlet flowrate and the measured outlet flowrate; and

determining whether a leak exists in the fluid conducting conduit based on the comparing.

2. The method set forth in claim 1, wherein said calculating a time series of expected average temperature comprises inputting the measured inlet flowrate and the measured outlet flowrate to a function that directly relates flowrate of fluid in the fluid conducting conduit to the temperature of the fluid.

3. The method set forth in claim 2, further comprising generating said function that directly relates flowrate of fluid in the fluid conducting conduit to the temperature of the fluid using pump and system curves for the fluid conducting conduit.

4. The method set forth in claim 1, wherein said analyzing the time series of expected average temperature of the fluid to generate said calculated time derivative of average temperature of the fluid comprises inputting the time series of expected average temperature of the fluid into a digital signal filter.

5. The method set forth in claim 4, wherein the digital signal filter comprises at least one of a smoothing filter and a low-noise differentiator filter.

6. The method set forth in claim 1, wherein said calculating a predicted difference in flowrate comprises inputting said calculated time derivative of average temperature into one of the following functions:

7. The method set forth in claim 1, wherein said comparing the measured difference in flowrate and the predicted difference in flowrate comprises determining whether the difference between said measured difference in flowrate and said predicted difference in flowrate is greater than or greater than or equal to a pre-defined threshold value.

8. A computer-implemented leak detection system for use in detecting a leak in a fluid conducting conduit, the leak detection system comprising:

a first flowrate sensor positioned adjacent an inlet of the fluid conducting conduit for measuring an inlet flowrate of fluid;

a second flowrate sensor positioned adjacent an outlet of the fluid conducting conduit for measuring an outlet flowrate of fluid; and

a processor and a memory, the processor configured to;

receive data, from the respective first and second flowrate sensors, relating to the measured inlet flowrate of fluid and the measured outlet flowrate of fluid;

generate a time series of expected average temperature of the fluid flowing in the fluid conducting conduit based on the measured inlet flowrate and the measured outlet flowrate;

calculate a time derivative of average temperature of fluid based on the measured inlet flowrate and the measured outlet flowrate by analyzing the time series of expected average temperature of the fluid;

calculate a predicted difference in flowrate between a flowrate of fluid in the fluid conducting conduit adjacent the inlet and a flowrate of fluid in the fluid conducting conduit adjacent the outlet based on the calculated time derivative of the average temperature of the fluid flowing in the fluid conducting conduit;

determine whether a leak exists in the fluid conducting conduit based on a comparison between the predicted difference in flowrate and a difference between the measured inlet flowrate and the measured outlet flowrate.

9. The computer-implemented leak detection system set forth in claim 8, wherein the processor is configured to:

input the measured inlet flowrate and the measured outlet flowrate into a function that directly relates flowrate of fluid in the fluid conducting conduit to the temperature of the fluid to calculate the time series of expected average temperature of the fluid.

10. The computer-implemented leak detection system set forth in claim 8, wherein the processor is configured to:

input the time series of expected average temperature of the fluid into a digital signal filter for use in generating said calculated time derivative of average temperature of the fluid.

11. The computer-implemented leak detection system set forth in claim 10, wherein the digital signal filter comprises at least one of a smoothing filter and a low-noise differentiator filter.

12. The computer-implemented leak detection system set forth in claim 8, wherein the processor is configured to:

input said calculated time derivative of average temperature into one of the following functions to calculate the predicted difference in flowrate;

13. The computer-implemented leak detection system set forth in claim 8, wherein the processor is configured to:

determine whether the difference between said measured difference in flowrate and said predicted difference in flowrate is greater than or greater than or equal to a pre-defined threshold value.

14. A non-transitory, computer-readable medium containing computer-readable instructions for use in detecting a leak in a fluid conducting conduit, wherein the computer-readable instructions are executable by a processor for performing the steps of:

receiving data, from a first flowrate sensor, relating to a measured inlet flowrate of fluid in the fluid conducting conduit;

receiving data, from a second flowrate sensor, relating to a measured outlet flowrate of fluid in the fluid conducting conduit;

generating a time series of expected average temperature of the fluid flowing in the fluid conducting conduit based on the measured inlet flowrate and the measured outlet flowrate; and

calculating a time derivative of average temperature of fluid based on the measured inlet flowrate and the measured outlet flowrate by analyzing the time series of expected average temperature of the fluid;

calculating a predicted difference in flowrate between a flowrate of fluid in the fluid conducting conduit adjacent the inlet and a flowrate of fluid in the fluid conducting conduit adjacent the outlet based on the calculated time derivative of the average temperature of the fluid flowing in the fluid conducting conduit;

determining whether a leak exists in the fluid conducting conduit based on a comparison between the predicted difference in flowrate and a difference between the measured inlet flowrate and the measured outlet flowrate.

15. The non-transitory, computer-readable medium set forth in claim 14, wherein the computer-readable instructions are executable by the processor for performing the step of:

inputting the measured inlet flowrate and the measured outlet flowrate into a function that directly relates flowrate of fluid in the fluid conducting conduit to the temperature of the fluid to calculate the time series of expected average temperature of the fluid.

16. The non-transitory, computer-readable medium set forth in claim 14, wherein the computer-readable instructions are executable by the processor for performing the step of:

inputting the time series of expected average temperature of the fluid into a digital signal filter for use in generating said calculated time derivative of average temperature of the fluid.

17. The non-transitory, computer-readable medium set forth in claim 16, wherein the digital signal filter comprises at least one of a smoothing filter and a low-noise differentiator filter.

18. The non-transitory, computer-readable medium set forth in claim 14, wherein the computer-readable instructions are executable by the processor for performing the step of:

inputting said calculated time derivative of average temperature into one of the following functions to calculate the predicted difference in flowrate;

19. The non-transitory, computer-readable medium set forth in claim 14, wherein the computer-readable instructions are executable by the processor for performing the step of:

determining whether the difference between said measured difference in flowrate and said predicted difference in flowrate is greater than or greater than or equal to a pre-defined threshold value.