Line leak detection

• US 5,918,268 A
• Filed: 06/09/1997
• Issued: 06/29/1999
• Est. Priority Date: 07/07/1995
• Status: Expired due to Term

• Current Assignee: Intelligent Controls, Inc.
• Original Assignee: Intelligent Controls, Inc.
• Inventors: Johnson, Daniel, Lukas, Paul, Farrar, Christopher D., Gillis, John J., Gagnon, Daniel F., Knight, John D.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): WIGGINS, JOHN DAVID
• Application Number:
  US08/871,394
• Time in Patent Office: 750 Days
• Field of Search: 73/40.5 R, 73/49.7, 73/204.22, 73/202.5, 73/49.1, 73/38, 340/605
• US Class Current: 73/40.50R
• CPC Class Codes: G01M 3/002 by using thermal means
• CPC Class Codes: G01M 3/2892 for underground fuel dispensing systems G01M3/30 takes precedence

Abstract

A flow measuring device for indicating the leak status of a pressurized fluid-carrying line pressurized by a pump includes an electronic leak sensing module connected in fluid communication with the pressurized line and configured for insertion within a detection port of a pump manifold. The module includes a thermal sensor effected by flow through the pressurized line, whereby leaks in the pressurized line are detected by monitoring the thermal sensor for changes in output signal that correspond to flow through the pressurized fluid-carrying line. The flow measuring device includes a system control unit for monitoring the electronic leak sensing module and indicating the leak status of the pressurized line. Wires which provide power to the leak sensing module, the system control unit and the pump for pressurizing the pressurized line are also used for communication.

Claims

1. A flow measuring device for indicating the leak status of a pressurized fluid-carrying line, the fluid-carrying line being pressurized by a pump, comprising:

an electronic leak sensing module connected in fluid communication with the pressurized line and configured for insertion within a detection port of a pump manifold, said module including a thermal sensor effected by flow through the pressurized line, whereby leaks in the pressurized line are detected by monitoring said thermal sensor for changes in output signal that correspond to flow through said pressurized fluid-carrying line, and

power lines which provide power to said leak sensing module and over which information is transmitted from said leak sensing module to a system control unit.

2. The flow measuring device of claim 1 further comprising a system control unit for monitoring said electronic leak sensing module and indicating the leak status of the pressurized line.

3. The flow measuring device of claim 1 wherein said information is transmitted by varying a current drawn on said power lines.

4. The flow measuring device of claim 3 wherein the current is drawn as a series of pulses.

5. The flow measuring device of claim 4 wherein said leak sensing module inserts a first and a second gap in said series of pulses, a predetermined number of pulses between said gaps containing information related to leak rate.

6. The flow measuring device of claim 3 further comprising a temperature controller including a heater, said current being drawn by said heater.

7. The flow measuring device of claim 4 wherein the current pulses represent serialized digital data.

8. The flow measuring device of claim 1 wherein said electronic leak sensing module further comprises a housing defining a flow delivery passage having an input and output coupled to said pressurized line and a detection passage coupled to said flow delivery passage, said thermal sensor being located along said detection passage.

9. The flow measuring device of claim 8 wherein said housing further includes a detection conduit enclosing and defining the pathway of said detection passage and said thermal sensor is located on said detection conduit.

10. A flow Measuring device for indicating the leak status of a pressurized fluid-carrying line, the fluid-carrying line being pressurized by a pump, comprising:

an electronic leak sensing module connected in fluid communication with the pressurized line and configured for insertion within a detection port of a pump manifold, said module including a thermal sensor effected by flow through the pressurized line, whereby leaks in the pressurized line are detected by monitoring said thermal sensor for chances in output signal that correspond to flow through said pressurized fluid-carrying line,

said module further comprising a housing defining a flow delivery passage having an input and an output coupled to said pressurized line and a detection passage coupled to said flow delivery passage, said thermal sensor being located along said detection passage,

a deflector plate disposed in said housing within said flow delivery passage to have a fluid flow switch function, said deflector plate having a first flow deflection position preventing flow through said flow delivery passage while allowing flow through said detection passage and a second flow position allowing flow through said flow delivery passage, and

a biasing element for biasing said deflector plate toward said first flow deflection position,

fluid flow through said pipeline above a predetermined value causing said deflector plate to move to said second flow position.

11. The flow measuring device of claim 10 wherein said biasing element is a spring.

12. The flow measuring device of claim 10 further including a temperature controller located on said detection conduit for controlling the temperature of said detection conduit.

13. The flow measuring device of claim 12 wherein said temperature controller comprises a heater for heating the detection conduit.

14. The flow measuring device of claim 13 wherein said heater is a coil of nichrome wire wound around said detection conduit.

15. The flow measuring device of claim 13 wherein said thermal sensor comprises a first thermal element located on an upstream side of said heater and a second thermal element located on a downstream side of said heater.

16. A flow measuring device for indicating the leak status of a pressurized fluid-carrying line, the fluid-carrying line being pressurized by a pump, comprising:

an electronic leak sensing module connected in fluid communication with the pressurized line and configured for insertion within a detection port of a pump manifold, said module including a thermal sensor effected by flow through the pressurized line, whereby leaks in the pressurized line are detected by monitoring said thermal sensor for changes in output signal that correspond to flow through said pressurized fluid-carrying line,

said electronic leak sensing module further comprising a housing defining a flow delivery passage having an input and an output coupled to said pressurized line and a detection passage coupled to said flow delivery passage, said thermal sensor being located along said detection passage, and a check valve located in a path of fluid entering said detection passage.

17. The flow measuring device of claim 16 wherein said housing defines a channel in fluid communication with said check valve and said detection passage.

18. A flow measuring device for indicating the leak status of a pressurized fluid-carrying line, the fluid-carrying line being pressurized by a pump, comprising:

an electronic leak sensing module connected in fluid communication with the pressurized line and configured for insertion within a detection port of a pump manifold, said module including a thermal sensor effected by flow through the pressurized line, whereby leaks in the pressurized line are detected by monitoring said thermal sensor for chances in output signal that correspond to flow through said pressurized fluid-carrying line,

said electronic leak sensing module further comprising a housing defining a flow delivery passage having an input and an output coupled to said pressurized line and a detection passage coupled to said flow delivery passage, said thermal sensor being located along said detection passage, and a relief valve located in the path of fluid entering said detection passage.

19. A flow measuring device for indicating the leak status of a pressurized fluid-carrying line, the fluid-carrying line being pressurized by a pump, comprising:

an electronic leak sensing module connected in fluid communication with the pressurized line and configured for insertion within a detection port of a pump manifold, said module including a thermal sensor effected by flow through the pressurized line, whereby leaks in the pressurized line are detected by monitoring said thermal sensor for changes in output signal that correspond to flow through said pressurized fluid-carrying line, said flow measuring device being a stand-alone unit located in the detection port of the pump manifold.

20. A flow measuring device for indicating the leak status of a pressurized fluid-carrying line, comprising:

an electronic leak sensing module connected in fluid communication with the pressurized line, said module including

a thermal sensor effected by flow through the pressurized line, whereby leaks in the pressurized line are detected by monitoring said thermal sensor for changes in output signal that correspond to flow through said pressurized fluid-carrying line,

a housing defining a flow delivery passage having an input and an output coupled to said pressurized line and a detection conduit enclosing and defining a detection passage coupled to said flow delivery passage, said thermal sensor being located on said detection conduit,

a deflector plate disposed in said housing within said flow delivery passage to have a fluid flow switch function, said deflector plate having a first flow deflection position preventing flow through said flow delivery passage while allowing flow through said detection passage and a second flow position allowing flow through said delivery passage,

a biasing element for biasing said deflector plate toward said first flow deflection position, fluid flow through said pipeline above a predetermined value causing said deflector plate to move to said second flow position,

a temperature controller located on said detection conduit for controlling the temperature of said detection conduit, said thermal sensor including a first thermal element located on an upstream side of said temperature controller and a second thermal element located on a downstream side of said temperature controller, and

a third thermal element located on said housing such that said third thermal element indicates a temperature of said housing which is unaffected by said temperature controller.

21. The flow measuring device of claim 20 wherein said electronic leak sensing module further includes a microprocessor for controlling said heater.

22. The flow measuring device of claim 21 wherein said microprocessor receives a signal from said third thermal element and a signal from said thermal sensor and provides a control signal to said heater representative of a first temperature difference between said detection conduit and said housing to control said heater to establish the first temperature difference at a desired pre-determined value.

23. The flow measuring device of claim 22 wherein said signal from said thermal sensor comprises a signal from said first thermal element representative of a temperature of said detection conduit on said upstream slide of said heater.

24. The flow measuring device of claim 22 wherein said signal from said thermal sensor comprises a signal from said second thermal element representative of a temperature of said detection conduit on said downstream side of said heater.

25. The flow measuring device of claim 22 wherein said signal from said thermal sensor comprises a signal from said first and second thermal elements representative of an average of a temperature of said detection conduit on said upstream side of said heater and a temperature of said detection conduit on said downstream side of said heater.

26. The flow measuring device of claim 22 wherein said control signal comprises a first pulse signal of current pulses of variable pulse widths that are generated at a desired set frequency, the width of each current pulse controlling an amount of electrical energy applied to said heater.

27. The flow measuring device of claim 26 further comprising a system control unit for monitoring said electronic leak sensing module.

28. The flow measuring device of claim 27 wherein said microprocessor receives a signal from said first and second thermal elements representative of a second temperature difference between the temperatures at said downstream and upstream locations of said detection conduit and provides a second pulse signal to said system control unit representative of said second temperature difference.

29. The flow measuring device of claim 28 further including wires which provide power to said leak sensing module, said wires also being used to communicate said second pulse signal from said leak sensing module to said system control unit.

30. The flow measuring device of claim 29 wherein said wires also provide power to a pump for pressurizing said pressurized line.

31. The flow measuring device of claim 29 wherein said microprocessor inserts a first and a second gap into said control signal, said gaps being interruptions in said set frequency in which no pulses are sent to said heater, said second pulse signal being the number of pulses sent to said heater between gaps.

32. The flow measuring device of claim 31 wherein said control unit monitors current drawn by said leak sensing module, a spike in the current drawn occurring during each current pulse of said control signal, said control unit interprets said second pulse signal by counting the number of spikes occurring between said gaps.

33. The flow measuring device of claim 27 further comprising an indicator including:

a two digit display for displaying test information,

a first LED for indicating when a leak test is being performed,

a second LED for indicating when a leak has been detected, and

a test/reset button for starting a test and resetting said device.

34. The flow measuring device of claim 33 wherein said control unit is retrofitable to a relay box associated with a pump for pressurizing said pressurized line.

35. The flow measuring device of claim 34 wherein the pump is a submersible pump for pumping liquid from a tank through the pressurized line to a dispenser,

said electronic sensing module being threadably engaged in a line leak port of the pump.

36. A flow measuring device for indicating the leak status of a pressurized fluid-carrying line, comprising:

an electronic leak sensing module connected in fluid communication with the pressurized line, said module including a detection conduit defining a fluid passage in fluid communication with said pressurized line,

a first heater in thermal contact with said detection conduit, and

a second heater in thermal contact with said detection conduit located downstream of said first heater,

a controller for monitoring the energy required by each of said first heater and said second heater to maintain said first and second heaters at a predetermined elevated temperature, said controller determining a difference in energy required to maintain each of said first heater and said second heater at the predetermined elevated temperature, said difference being proportional to flow rate.

37. The flow measuring device of claim 36 further including a first thermal element for monitoring the temperature of said first heater and a second thermal element for monitoring the temperature of said second heater.

38. The flow measuring device of claim 36 wherein the difference in power comprises a difference in integrated power.