Non-invasive Thermal Dispersion Flow Meter with Chronometric Monitor for Fluid Leak Detection and Freeze Burst Prevention

• US 20140348205A1
• Filed: 05/21/2013
• Published: 11/27/2014
• Est. Priority Date: 01/03/2011
• Status: Active Grant

• Current Assignee: Sentinel Hydrosolutions, LLC (Watts Water Technologies Incorporated)
• Original Assignee: Sentinel Hydrosolutions, LLC (Watts Water Technologies Incorporated)
• Inventors: Shaw, Scott, Trescott, Robert
• Granted Patent: US 9,759,632 B2
• Time in Patent Office: Days
• US Class Current: 374/142
• CPC Class Codes: E03B 7/071 Arrangement of safety devices in domestic pipe systems, e.g. devices for automatic shut-off
• CPC Class Codes: E03B 7/08 Arrangement of draining devices, e.g. manual shut-off valvesdraining devices in general F16K, F16L
• CPC Class Codes: E03B 7/09 Component parts or accessories tools for cleaning pipes B08B9/02; devices for preventing contamination of drinking water pipes for domestic use E03C1/10; devices for preventing damage in case of bursts of pipes F16L; heating or cooling of pipes or pipe systems F16L53/00
• CPC Class Codes: G01F 1/6847 where sensing or heating elements are not disturbing the fluid flow, e.g. elements mounted outside the flow duct
• CPC Class Codes: G01F 1/6888 Thermoelectric elements, e.g. thermocouples, thermopiles
• CPC Class Codes: G01F 1/69 of resistive type
• CPC Class Codes: G01F 1/696 Circuits therefor, e.g. constant-current flow meters
• CPC Class Codes: G01F 1/7084 using thermal detecting arrangements
• CPC Class Codes: G01K 13/02 for measuring temperature of moving fluids or granular materials capable of flow
• CPC Class Codes: G01K 13/026 of moving liquids
• CPC Class Codes: G01M 3/002 by using thermal means
• CPC Class Codes: G01M 3/2807 for pipes G01M3/2892, G01M3/30 take precedence

Abstract

A non-invasive thermal dispersion flow meter with chronometric monitor for fluid leak detection includes a heater, an ambient temperature sensor and a flow rate sensor which are configured to sense the temperature of a fluid in a conduit, and then monitor the flow of that fluid through the conduit. The fluid flow sensor is incorporated into a Wheatstone bridge circuit which is used to provide increased sensitivity to the outputs of the sensors. Based upon the ambient temperature sensor readings, the flow rate sensor and heater may be adjusted to optimize the operation of the system to detect leaks. An alternative embodiment utilizes a single sensor and separate heater which work together to determine heat propagation times which in turn is used to calculate flow rate. Based on the sensor readings, the flow may be adjusted to prevent damage and leaks by relieving the system of excess pressure.

Claims

1. A fluid leak detector for detecting leakage in a pressurized fluid system having a closed fluid conduit, the fluid leak detector comprising:

a first sensor in thermal communication with the outside of said conduit and capable of sensing the ambient temperature of the fluid within said conduit;

a second sensor in thermal communication with the outside of said conduit and responsive to a drive signal to elevate the temperature of said second sensor;

a means for generating a drive signal in communication with said second sensor to drive said second sensor to a temperature above the ambient temperature; and

a means for detecting the flow of fluid through said conduit.

2. The fluid leak detector of claim 1, wherein said means for detecting the flow of fluid through said conduit further comprises a means for sensing current flow through said second sensor.

3. The fluid leak detector of claim 1, wherein said means for generating a drive signal for said second sensor further comprises an adjustable Wheatstone bridge circuit wherein said second sensor represents an element in the bridge circuit responsive to said flow of fluid through said conduit.

4. The fluid leak detector of claim 3, further comprising an analog to digital converter in communication with said second sensor and said means for detecting the flow of fluid through said conduit, said analog to digital converter configured to sense said elevated temperature and generate a corresponding digital signal to said means for detecting.

5. The fluid leak detector of claim 4, further comprising a means for comparing said digital signal corresponding to said elevated temperature to a predetermined value.

6. The fluid leak detector of claim 5, further comprising an analog to digital converter in communication with said first sensor and said means for detecting the flow of fluid through said conduit, said analog to digital converter configured to sense said ambient temperature and generate a corresponding digital signal to said means for detecting.

7. The fluid leak detector of claim 4, further comprising a means for comparing said digital signal corresponding to said ambient temperature to a predetermined value.

8. The fluid leak detector of claim 1 wherein said first RTD sensor is mounted upstream from said second RTD sensor.

9. The fluid leak detector of claim 1, further comprising a shutoff valve in communication with said means for detecting fluid flow through said conduit, and responsive to a signal from said means for detecting to interrupt said fluid flow through said conduit.

10. The fluid leak detector of claim 1, further comprising a display in communication with said means for detecting, configured to display a status indicator of said fluid leak detector.

11. A device for interrupting the flow of fluid through a fluid conduit upon the detection of a leak, comprising:

an ambient temperature RTD sensor in thermal communication with said fluid conduit;

a flow-sensing RTD sensor in thermal communication with said fluid conduit;

a controller in electrical communication with said ambient temperature RTD sensor and said flow-sensing RTD sensor, said controller sensing an ambient temperature signal from said ambient temperature RTD sensor, and generating a driving signal to drive said second RTD sensor to a temperature greater than said ambient temperature;

a means for comparing the ambient temperature signal and the drive signal to a predetermined value and generating a shutoff signal in response thereto; and

a valve in communication with said controller to receive a shutoff signal from said controller to close said valve in response thereto.

12. The device of claim 11, wherein said controller further comprises:

a microprocessor;

a memory in communication with said microprocessor; and

an analog interface in communication with said microprocessor and capable of generating said driving signal.

13. The device of claim 12, wherein said memory further comprises a look-up table having ambient temperature data and corresponding drive signal level data for driving said second RTD sensor to a temperature greater than said ambient temperature.

14. The device of claim 11, further comprising a display in communication with said controller, said display configured to display a status indicator.

15. The device of claim 14, wherein said status indicator further comprises a HOME status indicator and an AWAY status indicator.

16. The device of claim 14, wherein said status indicator further comprises a LEAK status indicator.

17. The device of claim 14, wherein said status indicator further comprises a FLOW RATE indicator corresponding to a flow rate signal from said flow sensing RTD.

18. The device of claim 11, further comprising an external temperature sensor in communication with said controller and configured to generate a signal corresponding to said external temperature.

19. The device of claim 11, further comprising a program memory.

20. The device of claim 19, wherein said program memory further comprises an EEPROM in communication with said controller and configured to provide program instructions and look-up table data to said controller.

21. A device for interrupting the flow of fluid through a fluid conduit upon the detection of fluid expansion, comprising:

a primary temperature sensor in thermal communication with said fluid conduit located near the inlet of said fluid conduit configured to generate an analog temperature signal corresponding to said fluid temperature;

a secondary temperature sensor package in thermal communication with said fluid conduit and located near the end of said fluid conduit configured to generate an analog temperature signal corresponding to said fluid temperature;

an external temperature sensor in thermal communication with external environment of said fluid conduit configured to generate an analog temperature signal corresponding to said external temperature;

a controller in electrical communication with said primary temperature sensor, said secondary temperature sensor, and said external environmental temperature sensor, said controller sensing said analog temperature signals from said primary temperature sensor, said secondary temperature sensor, and said external environmental temperature sensor;

a means for comparing said primary temperature sensor temperature signal, said secondary temperature sensor temperature signal, and said external environmental temperature sensor signal to predetermined user-inputted values and generating an open signal in response thereto;

a relief valve located towards the end of said fluid conduit in communication with said controller to receive an open signal from said controller to open said valve allowing said fluid to flow through a drainage pipe in response thereto.

22. The device of claim 21, wherein said controller further comprises;

a microprocessor;

a signal processor in communication with said microprocessor capable of converting said analog temperature signals from said primary temperature sensor, said secondary temperature sensor, and said external environmental temperature sensor to digital temperature signals; and

a memory in communication with said microprocessor.

23. The device of claim 22, wherein said memory further comprises

a look-up table having said digital temperature sensor signals and corresponding fluid temperature and fluid expansion data;

an EEPROM in communication with said microprocessor and configured to provide said user-inputted values and look-up data to said microprocessor.

24. A device for evacuating fluid upon the detection of fluid expansion in a pressurized fluid conduit, the device comprising:

a primary temperature sensor in thermal communication with said fluid conduit located near the inlet of said fluid conduit configured to generate an analog temperature signal corresponding to said fluid temperature;

a secondary temperature sensor package in thermal communication with said fluid conduit and located near the end of said fluid conduit configured to generate an analog temperature signal corresponding to said fluid temperature;

an external temperature sensor in thermal communication with external environment of said fluid conduit configured to generate an analog temperature signal corresponding to said external temperature;

a controller in electrical communication with said primary temperature sensor, said secondary temperature sensor, and said external environmental temperature sensor, said controller sensing said analog temperature signals from said primary temperature sensor, said secondary temperature sensor, and said external environmental temperature sensor;

a means for comparing said primary temperature sensor temperature signal, said secondary temperature sensor temperature signal, and said external environmental temperature sensor signal to predetermined user-inputted values and generating an open or close signal in response thereto;

an isolation valve located near the inlet of said fluid conduit in communication with said controller to receive said close signal from said controller to close said valve in response thereto;

a relief valve located towards the end and at a high point of said fluid conduit in communication with said controller to receive said open signal from said controller to open said valve allowing said fluid to flow through a drainage pipe in response thereto; and

an air valve located at a high point in said fluid conduit in communication with said controller to receive said open signal from said controller to open said valve to allow atmospheric air to enter said fluid conduit in response thereto.

25. The device of claim 24, wherein said controller further comprises;

a microprocessor;

a signal processor in communication with said microprocessor capable of converting said analog temperature signals from said primary temperature sensor, said secondary temperature sensor, and said external environmental temperature sensor to digital temperature signals; and

a memory in communication with said microprocessor.

26. The device of claim 25, wherein said memory further comprises

a look-up table having said digital temperature sensor signals and corresponding fluid temperature and fluid expansion data;

an EEPROM in communication with said microprocessor and configured to provide said user-inputted values and look-up data to said microprocessor.

27. A method for evacuating a closed fluid conduit when expansion of said fluid is occurring, comprising:

providing a primary temperature sensor capable of sensing fluid temperature and producing corresponding analog temperature signals;

providing a secondary temperature sensor capable of sensing fluid temperature and producing corresponding analog temperature signals;

providing an external temperature sensor capable of sensing fluid temperature and producing corresponding analog temperature signals;

providing a signal processor capable of converting said analog temperature signals to digital temperature signals;

converting said analog temperature signals to said digital temperature signals;

providing a memory which is able to store a series of look-up tables corresponding to said digital temperature signals with fluid expansion data;

providing a means for comparing said digital temperature signals with said data from said look-up tables;

providing a microprocessor capable of producing a drive signal in response to said digital temperature data;

providing an isolation valve located at the inlet of said fluid conduit capable of closing in response to receiving said drive signal;

providing a relief valve located near the end of said fluid conduit at a low point capable of opening in response to receiving said drive signal;

providing an air valve located at a high point of said fluid conduit capable of opening in response to receiving said drive signal;

whereby said fluid conduit will evacuate said fluid in said fluid conduit by first closing said isolation valve, then open said relief valve, then open said air valve when said fluid is expanding.