NON-INTRUSIVE PROCESS FLUID TEMPERATURE CALCULATION SYSTEM

• US 20170212065A1
• Filed: 03/25/2016
• Published: 07/27/2017
• Est. Priority Date: 01/25/2016
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Rud, Jason H., Kuznetsov, Yury Nickolayevich, Garipov, Sait Saitovich, Krivonogov, Aleksey Aleksandrovich, Fomchenko, Sergey Andreyevich, Repyevsky, Vladimir Victorovich
• Granted Patent: US 10,670,546 B2
• Time in Patent Office: Days
• CPC Class Codes: G01K 1/143 for measuring surface temperatures
• CPC Class Codes: G01K 13/02 for measuring temperature of moving fluids or granular materials capable of flow
• CPC Class Codes: G01K 17/06 Measuring quantity of heat conveyed by flowing media, e.g. in heating systems G01K17/02, G01K17/04 take precedencee.g. the quantity of heat in a transporting medium, delivered to or consumed in an expenditure device
• CPC Class Codes: G01K 7/02 using thermoelectric elements, e.g. thermocouples
• CPC Class Codes: G01K 7/427 Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation
• CPC Class Codes: G01N 25/18 by investigating thermal conductivity by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18

Abstract

A process fluid temperature calculation system includes a first temperature sensor disposed to measure an external temperature of a process fluid conduit. The process fluid temperature calculation system has a stem portion having a known thermal impedance. A second temperature sensor is spaced from the first temperature sensor by the stem portion. Measurement circuitry is coupled to the first and second temperature sensors. A microprocessor is coupled to the measurement circuitry to receive temperature information from the measurement circuitry and to provide an estimate of temperature of process fluid within the process fluid conduit using a heat flux calculation.

Claims

1. A process fluid temperature calculation system comprising:

a first temperature sensor disposed to measure an external temperature of a process fluid conduit;

a stem portion having a known thermal impedance;

a second temperature sensor spaced from the first temperature sensor by the stem portion;

measurement circuitry coupled the first and second temperature sensors; and

a microprocessor coupled to the measurement circuitry to receive temperature information from the measurement circuitry and to calculate a process fluid temperature output using a heat flux calculation.

2. The process fluid temperature calculation system of claim 1, and further comprising a clamp configured to attach to the process fluid conduit and maintain thermal contact between the process fluid conduit and the first temperature sensor.

3. The process fluid temperature calculation system of claim 1, and further comprising a housing attached to the stem portion, the housing containing the measurement circuitry, the second temperature sensor and the microprocessor.

4. The process fluid temperature calculation system of claim 3, and further comprising a terminal block disposed within the housing, the terminal block mounting the second temperature sensor.

5. The process fluid temperature calculation system of claim 3, and further comprising memory containing parameters for calculating heat flux.

6. The process fluid temperature calculation system of claim 5, wherein the parameters include physical characteristic of a wall of the process fluid conduit.

7. The process fluid temperature calculation system of claim 6, wherein the physical characteristic includes a material from which the process fluid conduit is constructed.

8. The process fluid temperature calculation system of claim 6, wherein the physical characteristic is process fluid conduit wall thickness.

9. The process fluid temperature calculation system of claim 1, and further comprising thermal insulation disposed about the process fluid conduit adjacent the first temperature sensor.

10. The process fluid temperature calculation system of claim 1, and further comprising thermal insulation disposed about the stem portion.

11. The process fluid temperature calculation system of claim 1, wherein the microprocessor is configured to dynamically compensate temperature output based on a rate of change of temperature measured by the first temperature sensor.

12. The process fluid temperature calculation system of claim 1, wherein the microprocessor is configured to dynamically compensate the temperature output based on a rate of change of temperature measured by the second temperature sensor.

13. The process fluid temperature calculation system of claim 1, wherein the microprocessor is configured to dynamically compensate the temperature output based on a rate of change of temperature measured by the first temperature sensor in comparison to a rate of change of temperature measured by the second temperature sensor.

14. The process fluid temperature calculation system of claim 1, and further comprising a communication interface configured to communicate the output to a remote device.

15. The process fluid temperature calculation system of claim 1, and further comprising a local operator interface coupled to the microprocessor.

16. The process fluid temperature calculation system of claim 1, wherein the measurement circuitry includes a plurality of analog-to-digital converters, a first analog-to-digital converter being coupled to the first temperature sensor and a second analog-to-digital converter being coupled to the second temperature sensor.

17. A method of calculating a temperature of process fluid within a process fluid conduit, the method comprising:

measuring a temperature of an external surface of the process fluid conduit;

measuring a temperature of a location spaced from the process fluid conduit by a stem portion having a known thermal impedance;

using a heat flux equation and the measured temperatures from the external surface of the process fluid conduit and the location spaced from the process fluid conduit by the stem portion to calculate heat flux; and

using the calculated heat flux in combination with a thermal impedance parameter of a wall of the process fluid conduit to calculate the temperature of process fluid within the process fluid conduit; and

providing the calculated temperature as an output.

18. The method of claim 17, and further comprising providing a process fluid having a known temperature in the process fluid conduit, and updating the known thermal impedance of the stem portion for calibration.

19. The method of claim 17, and further comprising dynamically compensating the estimation of process fluid temperature based on a rate of change of measurements of the external surface of the process fluid conduit.

20. A process fluid temperature calculation system comprising:

a pipe clamp;

a first temperature sensor coupled to the pipe clamp and configured to measure an external temperature of a process fluid conduit;

a stem portion coupled to the pipe clamp, the stem portion having a known thermal impedance;

a housing coupled to the stem portion, the housing containing a terminal block, measurement circuitry, and a microprocessor;

a second temperature sensor mounted to the terminal block within the housing;

wherein the measurement circuitry is coupled to the microprocessor and to the first and second temperature sensors; and

wherein the microprocessor is configured to provide a process fluid temperature output using a heat flux calculation and information from the measurement circuitry indicative of the external temperature of the process fluid conduit and the terminal block.