Heat flux sensor

• US 10,317,295 B2
• Filed: 09/30/2016
• Issued: 06/11/2019
• Est. Priority Date: 09/30/2016
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Rud, Jason H., Kassen, Allen John
• Primary Examiner(s): Jagan, Mirellys
• Application Number:
  US15/282,760
• Publication Number:
  US 20180094990A1
• Time in Patent Office: 984 Days
• Field of Search: 374 29, 374183, 374185, 374166, 374208
• CPC Class Codes: G01K 13/02 for measuring temperature of moving fluids or granular materials capable of flow
• CPC Class Codes: G01K 17/00 Measuring quantity of heat measuring temperature by calorimetry G01K3/00 - G01K11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion G01N
• CPC Class Codes: G01K 3/14 in respect of space
• CPC Class Codes: G01K 7/16 using resistive elements resistive elements per se H01C, H01L
• CPC Class Codes: G01K 7/427 Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation

Abstract

A heat flow sensor configured to provide an indication of temperature relative to a process fluid is provided. The sensor comprises a first resistance temperature detector (RTD) element and a second RTD element spaced within a sheath from the first RTD element. The sensor also includes a set of leads comprising a first subset and a second subset, wherein the first subset is coupled to the first RTD element and the second subset is coupled to the second RTD element.

Claims

1. A heat flow sensor configured to provide an indication of temperature relative to a process fluid, the heat flow sensor comprising:

a first resistance temperature detector (RTD) element;

a second RTD element spaced within a sheath from the first RTD element; and

a set of leads comprising a first subset and a second subset, wherein the first subset is coupled to the first RTD element and the second subset is coupled to the second RTD element; and

wherein the first RTD element and second RTD element face opposite directions.

2. The heat flow sensor of claim 1, wherein a processor is configured to estimate the temperature of the process fluid based on signals from the first and second RTD elements.

3. The heat flow sensor of claim 1, wherein the first RTD element comprises a forward facing RTD element.

4. The heat flow sensor of claim 1, wherein the first RTD element comprises a reverse bore RTD element.

5. The heat flow sensor of claim 1, wherein the first subset of leads comprises a first lead and a second lead, the second subset of leads comprises a third lead and a fourth lead.

6. The heat flow sensor of claim 1, wherein the set of leads comprises six leads.

7. The heat flow sensor of claim 1, wherein the first and second RTD elements are positioned within a sensor capsule.

8. The heat flow sensor of claim 1, wherein the first subset and the second subset are physically coupled.

9. The heat flow sensor of claim 1, wherein the sensor is positioned to contact an outer surface of a conduit of the process fluid.

10. The heat flow sensor of claim 9, wherein the first RTD element is a forward facing RTD element that is positioned toward the outer surface of the conduit.

11. The heat flow sensor of claim 1, wherein the second RTD element is spaced from the first RTD element by mineral insulation.

12. The heat flow sensor of claim 11, wherein the mineral insulation comprises a first mineral insulation layer and a second mineral insulation layer.

13. The heat flow sensor of claim 12, wherein one of the first and second RTD elements is positioned substantially within the first mineral insulation layer.

14. The heat flow sensor of claim 12, wherein one of the first and second RTD elements is positioned such that it spans an interface between the first mineral insulation layer and the second mineral insulation layer.

15. A heat flow sensor comprising:

a first resistance-based temperature sensing element coupled to a first lead and a second lead;

a second resistance-based temperature sensing element coupled to a third lead and a fourth lead;

a physical coupling between the second lead and the third lead; and

wherein the first resistance-based temperature sensing element is configured to operate as a first three-lead resistance detection system, the second resistance-based temperature sensing element is configured to operate as a second three-lead resistance detection system, and wherein the first and second three-lead resistance detection system are configured to independently detect a resistance.

16. The heat flow sensor of claim 15, wherein the first and second resistance-based temperature sensing elements comprise resistance temperature detector (RTD) elements.

17. The heat flow sensor of claim 15, wherein the first and second resistance-based temperature sensing elements are substantially surrounded by a mineral insulation.

18. The heat flow sensor of claim 15, wherein the physical coupling comprises a short.

19. The heat flow sensor of claim 15, wherein the first resistance-based temperature sensing element comprises a forward facing RTD element.

20. The heat flow sensor of claim 19, wherein the resistance-based temperature second sensing element comprises a reverse bore sensing element.