Heat flux temperature sensor probe and temperature measurement assembly comprising the same

Abstract

The present disclosure provides a heat flux temperature sensor probe for non-invasive process fluid temperature applications and a temperature measurement assembly including the same. The probe includes a first mineral insulated cable portion and a second mineral insulated cable portion. The first and second mineral insulated cable portions each have a metal sheath, a plurality of thermocouple conductors extending in the metal sheath, and an inorganic insulating material insulating the plurality of thermocouple conductors from each other and from the metal sheath. A first thermocouple is formed between at least one of the first plurality of thermocouple conductors and one of the second plurality of thermocouple conductors near a first end of the second mineral insulated cable portion. A second thermocouple is formed between at least two of the second plurality of thermocouple conductors near a second end of the second mineral insulated cable. A sheath is coupled to and connects the first and second mineral insulated cable portions. The probe can be deployed at any location along a process fluid conduit, overcoming the use limitations of the prior art.

Description

Technical Field

[0001] The present invention relates to a heat flux temperature sensor probe for non-invasive process fluid temperature applications and a temperature measurement assembly including the probe. Background Technology

[0002] Many industrial processes transport process fluids via pipes or other conduits. These process fluids can include liquids, gases, and sometimes entrained solids. These process fluid flows can be found in a wide variety of industries, including but not limited to, the production of sanitary food and beverages, water treatment, the manufacture of high-purity pharmaceuticals, chemical processing, the hydrocarbon fuel industry including hydrocarbon extraction and processing, and hydraulic fracturing technology utilizing corrosive and abrasive slurries.

[0003] Typically, a temperature sensor is placed inside a thermocouple sheath, which is then inserted into the process fluid flow through a hole in a conduit. However, this method may not always be practical because the process fluid may be very hot, highly corrosive, or both. Additionally, the thermocouple sheath usually requires a threaded port or other robust mechanical installation / seal in the conduit, thus necessitating its design in a defined location within the process fluid flow system. Therefore, while thermocouple sheaths can be used to provide accurate process fluid temperatures, they have several limitations.

[0004] Recently, process fluid temperatures have been estimated by measuring the external temperature of process fluid conduits (such as pipes) and using heat flux calculations. This external method is considered non-invasive because it does not require defining any holes or ports in the conduit. Therefore, this non-invasive method can be deployed almost anywhere along the conduit. Summary of the Invention

[0005] The heat flux temperature sensor probe includes a first mineral-insulated cable section and a second mineral-insulated cable section. The first mineral-insulated cable section has a first metal sheath, a first plurality of thermocouple conductors extending within the first metal sheath, and an inorganic insulating material that insulates the first plurality of thermocouple conductors from each other and from the first metal sheath. The second mineral-insulated cable section has a second metal sheath, a second plurality of thermocouple conductors extending within the second metal sheath, and an inorganic insulating material that insulates the second plurality of thermocouple conductors from each other and from the second metal sheath. A first thermocouple is formed near a first end of the second mineral-insulated cable section between at least one of the first plurality of thermocouple conductors and one of the second plurality of thermocouple conductors. A second thermocouple is formed near a second end of the second mineral-insulated cable section between at least two of the second plurality of thermocouple conductors. The sheath is operatively coupled to and connects the first and second mineral-insulated cable sections, and a portion of the interior of the sheath is filled with a non-conductive material. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of a temperature measuring component that is particularly useful in embodiments of the present invention.

[0007] Figure 2 This is a schematic diagram of a pipe skin measurement assembly that is particularly useful in embodiments of the present invention.

[0008] Figure 3 This is a block diagram of the electronic device for process fluid temperature measurement components.

[0009] Figure 4A and Figure 4B This is a schematic cross-sectional view of a heat flux sensor for a non-invasive process fluid temperature measurement system according to an embodiment of the present invention.

[0010] Figures 5A to 5D This is a variation of the thermocouple configuration according to an embodiment of the present invention.

[0011] Figure 6A and Figure 6B This is a schematic cross-sectional view of a heat flux sensor for a non-invasive process fluid temperature measurement system according to another embodiment of the present invention.

[0012] Figure 7 This is a flowchart of a method for manufacturing a heat flux sensor according to an embodiment of the present invention. Detailed Implementation

[0013] There are many applications, among which heat flux measurement provides a better method for measuring process temperature. For example, the Rosemount X-Well provided by Emerson Automation Solutions... TM This technology can be used to measure process temperature in a non-invasive or non-surgical manner. It uses pipe surface (skin) temperature measurements, reference temperature measurements from locations spaced apart from the pipe surface, known thermal relationships between temperature sensor locations (e.g., length and thermal conductivity), and heat flux calculations to infer the inner surface temperature of the process fluid conduit, thereby inferring the temperature of the process fluid within the conduit. Heat flux sensors can provide both skin temperature sensors and reference temperature sensors; however, component placement is crucial to ensuring adequate performance and providing a correct understanding of heat flux.

[0014] Figure 1 This is a schematic diagram of a temperature measurement assembly particularly useful in the embodiments described herein. Assembly 100 includes a sensor assembly 130 coupled to a processing container wall 110. The coupling may be a pipe clamp 120, such as... Figure 1 As shown. Sensor assembly 130 has multiple leads 150 extending to transmitter 140, which can be locally connected to sensor assembly 130 or remotely connected to sensor assembly 130. Transmitter 140 includes a controller configured to perform heat flux calculation.

[0015] Figure 2 This is a schematic diagram of a pipe skin measurement assembly particularly useful in embodiments of the present invention. System 200 includes a pipe 110 coupled to a heat flux temperature probe 220 via a pipe clamp 212. The heat flux temperature probe 220 is directly coupled to a transmitter 222. The transmitter 222 can be configured to calculate heat flux based on signals received from the heat flux temperature probe 220. The heat flux temperature probe 220 is pressed against the outer diameter of the pipe 110 by a spring 208. Although the spring 208 is shown, those skilled in the art will understand that various techniques can be used to maintain continuous contact between the heat flux temperature probe 220 and the pipe 110. The heat flux temperature probe 220 includes multiple temperature-sensitive elements, such as thermocouples. These thermocouples are electrically connected to a transmitter circuit within a housing 210, which is configured to obtain temperature measurements from the heat flux temperature probe 220 and calculate an estimate of the process fluid temperature based on these measurements.

[0016] In one example, the basic heat flow calculation can be simplified to:

[0017] T 校正 =T 皮肤 +(T 皮肤 -T 参考 )*(R 管道 / R传感器 ).

[0018] In this equation, T 皮肤 This is the measured temperature of the outer surface of the catheter. Furthermore, the T reference is obtained relative to the measured T. 皮肤 The temperature sensor has a fixed thermal impedance (R sensor) at its location to obtain a second temperature. 管道 It is the thermal resistance of the conduit, and can be manually obtained by acquiring information about the conduit material and wall thickness. As a supplement or alternative, it is related to R... 管道 The relevant parameters can be determined and stored during calibration for later use. Therefore, using appropriate heat flux calculations (such as those described above), the circuitry within housing 210 can calculate an estimate of the process fluid temperature (T). 校正 And transmit the indication of the temperature of this process fluid to the appropriate equipment and / or control room.

[0019] Figure 3 This is a block diagram of device electronics according to an embodiment of the present invention. Electronic device 300 may be housed within electronic device housing 210. Electronic device housing 210 may be associated with a transmitter, an example of which is transmitter 222 (e.g., Figure 2 (As shown). Furthermore, at least some of the electronic devices 300 may form part of a sensor assembly, such as the sensors described herein. In one embodiment, the electronic device 300 includes a processor 350, one or more analog-to-digital (AD) converters 354, and a memory 356. The processor 350 may be a digital microprocessor. The memory 356 may include a digital data storage device electronically coupled to the processor 350. The electronic device 300 may be locally accessible via a local operator interface 366, which may, for example, display temperature or device status.

[0020] The processor 350 is connected to a temperature sensor, such as the one discussed herein, via a coupling between an A / D converter 354 and one or more sensor leads 342.

[0021] In one embodiment, the electronic device 300 may further include a communication interface 358. The communication interface 358 provides communication between the electronic device 300 and a control or monitoring system 362. The electronic device 300 can transmit the calculated temperature of the process fluid within the process to the control system 362. Communication between the temperature measurement component 300 and the control system 362 can be achieved via any suitable wireless or hardwired connection. For example, communication can be represented by an analog current with a value in the range of 4-20 mA on a two-wire loop. Alternatively, it can use... Digital protocols communicate digitally over a two-wire loop, or use protocols such as FOUNDATION. TMDigital protocols such as fieldbus communicate on a communication bus.

[0022] Communication interface 358 may optionally include wireless communication circuitry 364, which is used for communication via wireless transmission using a wireless protocol such as WirelessHART (IEC 62591). Furthermore, communication with controller monitoring system 362 can be direct or via a network of any number of intermediate devices, such as a wireless mesh network. Figure 3 (Not shown in the image). Communication interface 358 can help manage and control communication to and from temperature measurement component 300. For example, control or measurement system 362 can provide configuration of temperature measurement component 300 through communication interface 358, including inputting or selecting basic structural parameters, processing container wall parameters, or selecting a heat transfer model for a specific application.

[0023] According to the embodiments described herein, a simplified heat flux temperature probe and a method for manufacturing the probe are provided, which generally improves manufacturability, reduces manufacturing costs, and utilizes existing manufacturing processes. Some embodiments described herein utilize commercially available MI (mineral insulated) cables, also known as MIMS (mineral insulated metal-sheathed) cables. MI cables typically have a metal sheath, which is generally cylindrical in shape and contains a plurality of conductors passing through it. The conductors are insulated from each other and from the metal sheath by inorganic powders (e.g., magnesium oxide (MgO) or ceramics). Various different metal sheath materials and conductors passing through the metal sheath can be specified for MI cables. Furthermore, the conductors can be specified as thermocouple metals. Examples of thermocouple metals include metals used for type J thermocouples (i.e., iron-constantan), type K thermocouples, type N thermocouples, type E thermocouples, and type T thermocouples (i.e., copper-constantan). Additionally, the metal sheath can also be specified as, for example, 304 stainless steel, 310 stainless steel, 316 stainless steel, 321 stainless steel, and chromium-nickel-iron alloys. One of MI Cable's commercial suppliers is Omega Engineering, based in Norwalk, Connecticut.

[0024] Figure 4A and Figure 4BThis is a schematic cross-sectional view of a heat flux sensor for a non-invasive process fluid temperature measurement system according to an embodiment of the present invention. The heat flux sensor 400 is typically formed from multiple portions 402, 404 of an MI cable. Each MI cable portion thus has a metal sheath 406 containing a plurality of thermocouple conductors 408 insulated from each other and from the metal sheath 406 by an inorganic powder 410. As described above, the inorganic powder 410 is typically magnesium oxide or ceramic. A first MI cable portion 402 is shown having three thermocouple conductors 408, 410, and 411. Of these three conductors, conductors 408 and 410 are joined together at a cold-end thermocouple junction 412 located between the first MI cable portion 402 and the second MI cable portion 404. In addition, the second MI cable portion 404 has a plurality of thermocouple conductors 407, 409, which terminate at the sensor end cap 414 to form a hot-end thermocouple junction 416.

[0025] like Figure 4A and Figure 4B As can be seen, some conductors in the first MI cable section are electrically coupled to conductors in the second MI cable section, for example, by welding. In the example shown, conductor 411 of MI cable section 402 is welded to conductor 407 of the second MI cable section 404 at position 424. Similarly, conductors 408 and 410 of MI cable section 402 are welded to conductor 409 of MI cable section 404 at position 426. When thermocouple wires in one MI cable section are welded to thermocouple wires in another cable to simply couple the two conductors together (i.e., without creating a thermocouple), the two conductors must be of the same metal.

[0026] Figure 4A and Figure 4B A support tube 418 is also shown disposed along the entire length of the second MI cable section 404 and a portion of the first MI cable 402. The support tube 418 is secured to the metal sheath 406 of the first MI cable 402 by a suitable process (e.g., welding).

[0027] Figure 4A and Figure 4B The illustrated design can utilize commercially available off-the-shelf MI cables and MgO powder, allowing for high precision in the joint positioning (i.e., the position of the cold-end joint thermocouple 412 relative to the hot-end joint thermocouple 416). Preferably, after the thermocouple joints are formed, the first MI cable portion 402 and the second MI cable portion 404 are welded to an external support tube 418. The support tube 418 includes a hole 420 (in... Figure 4BAs shown in the diagram, after the thermocouple junction is formed, the hole 420 allows the cavity 422 between the first MI cable portion 402 and the second MI cable portion 404 to be filled with a suitable insulator (e.g., MgO or ceramic). Once the cavity 422 is filled, the hole 420 can be sealed by creating a weld to fill it. Depending on the spacing between the conductors and the metal sidewalls, air may be sufficient as an electrical insulator, replacing the insulating material 410. In this case, the hole 420 may not be necessary. As will be understood, a wide variety of wiring combinations can be employed according to the embodiments described herein by specifying different numbers of conductors in the MI cable portions.

[0028] Figures 5A to 5D This is a variation of the thermocouple configuration according to an embodiment of the present invention. Figure 5A A three-wire MI cable is shown that is combined with a two-wire MI cable. Figure 5B A four-wire MI cable is shown, connected to a two-wire MI cable. It can be seen that joints 412 and 416 share a single conductor, and one wire is not used. Figure 5C The diagram shows the first MI cable, which is a four-wire cable, being joined to a two-wire MI cable. Note that joints 412 and 416 do not share a conductor.

[0029] exist Figure 5D In this embodiment, a single four-wire MI cable is used, and material is simply removed at the second joint. Thus, the two conductors after the second joint are not used. A similar configuration can also be achieved using a single three-wire MI cable with a common conductor. In either such embodiment, the outer sheath 406 or a portion thereof of the MI cable is removed at the location of the second joint. Two wires of the four-wire MI cable are cut and soldered together at this location to form a cold-end thermocouple joint 412. Then, a suitable sleeve (e.g., sleeve 502) is used. Figure 6A The sleeve is covered by the junction and welded or otherwise attached to the MI cable. If necessary, holes in the sleeve can be used to fill and then seal the junction. This particular embodiment allows for more precise positioning of the second junction thermocouple relative to the hot-end thermocouple junction. As mentioned above, the positioning of the second-end thermocouple junction becomes critical when employing algorithms or process techniques that rely on the thermal resistance between these two locations. This thermal resistance is based on the material through which heat flows (e.g., typically the MI cable) and the length through which the heat must flow.

[0030] Figure 6A and Figure 6BThis is a schematic cross-sectional view of a heat flux sensor for a non-invasive process fluid temperature measurement system according to another embodiment of the present invention. Heat flux sensor 500 shares some similarities with heat flux sensor 400, and similar components are similarly numbered. One difference between sensor 400 and sensor 500 is that the support tube 502 does not extend to cover the full length of one of the MI cable portions 402 and 404. Instead, the support tube 502 only extends to cover the portion of each of the MI cables 402 and 404 near the cold-end thermocouple junction 412. Figure 6B As shown, the support tube 502 does indeed include a filling hole 420 through which an insulating material is disposed. While the insulating material in this embodiment may be an inorganic powder, such as MgO or ceramic, it is also explicitly envisioned that a potting material such as epoxy resin may be introduced through the hole 420 to create an environmental seal.

[0031] exist Figure 6A and Figure 6B In the illustrated embodiment, the support tube 502 is attached to the first MI cable portion 402 and the second MI cable portion 404 at corresponding interfaces 504, 506. A weld may be provided at each of these attachment interfaces. However, it is also explicitly envisioned that the support tube 502 may be crimped to the first MI portion 402 rather than via a welded interface 504. This is especially true when an environmental seal is created using potting material.

[0032] Another difference between sensor 500 and sensor 400 is that sensor 500 does not require an end cap coupled to the hot-junction thermocouple 416. Instead, the hot-junction thermocouple 416 is connected to the sheath 406 of the second MI cable 404 at location 508, thereby grounding. However, in an alternative embodiment, the hot-junction thermocouple 416 may be connected to an end cap for grounding, which is welded or otherwise mounted to the end of the second MI cable 404.

[0033] It is understood that while the embodiments described to date typically use commercially available MI cables to provide a pair of thermocouples spaced at a precise distance, it is also clearly envisioned that, according to the various techniques described herein, more than two thermocouples can be provided by simply adding additional MI cable sections and couplings. Therefore, sensors having three or more thermocouples spaced apart along the MI cable are explicitly contemplated, with each thermocouple electrically coupled to the measurement circuitry of a temperature measurement system employing heat flux calculations.

[0034] Figure 7 This is a flowchart of a method for manufacturing a heat flux sensor according to an embodiment of the present invention. Method 600 begins at block 602, where a first MI thermocouple cable portion is provided. An example of such a cable is shown below. Figure 4A and Figure 4BThe figure is shown by reference numeral 402. Next, at box 604, a second MI thermocouple cable is provided. An example of the second MI thermocouple cable is shown in... Figure 4A The figure is shown with reference numeral 404. Next, at box 606, a first thermocouple is created between the first MI thermocouple cable and the second MI thermocouple cable. The first thermocouple is considered to be the cold junction thermocouple joint. Next, at box 608, a second thermocouple is formed at the end of one of the first MI thermocouple cables opposite to the first thermocouple. An example of this second thermocouple is shown in... Figure 4A The figure is shown with reference numeral 416. It can be seen that thermocouple 416 is located at the end of the second MI cable 404 opposite to the cold end thermocouple 412.

[0035] Next, at frame 610, a sleeve is slid across the first thermocouple and coupled to the first MI thermocouple cable and the second MI thermocouple cable, for example, by welding or crimping. This sleeve may be a support sleeve 418 (e.g., Figure 4A (as shown) or support sleeve 502 (as shown) Figure 6A (As shown). Next, at frame 612, the sleeve is filled with an insulating material. Step 612 may be optional depending on the spacing between the conductor and the sidewall. This insulating material may be MgO powder 614, ceramic powder 616, or potting material 618. Next, at frame 620, the sleeve is sealed. In embodiments using MgO powder 614 or ceramic powder 616, the sleeve is sealed by welding the holes for introducing the powder. In embodiments using potting insulating material 618, the seal is simply applied by curing the potting material.

[0036] Although the invention has been described with reference to preferred embodiments, those skilled in the art will recognize that modifications in form and detail may be made without departing from the spirit and scope of the invention.

Claims

1. A heat flux temperature sensor probe, comprising: The first mineral-insulated cable portion has a first metal sheath, a first plurality of thermocouple conductors extending in the first metal sheath, and an inorganic insulating material that insulates the first plurality of thermocouple conductors from each other and from the first metal sheath. The second mineral-insulated cable portion has a second metal sheath, a second plurality of thermocouple conductors extending in the second metal sheath, and an inorganic insulating material that insulates the second plurality of thermocouple conductors from each other and from the second metal sheath. A first thermocouple is formed near the first end of the second mineral-insulated cable portion between at least one of the first plurality of thermocouple conductors and one of the second plurality of thermocouple conductors; A second thermocouple is formed near the second end of the second mineral-insulated cable between at least two of the second plurality of thermocouple conductors; as well as A sheath, operatively coupled to and connecting the first mineral-insulated cable portion and the second mineral-insulated cable portion, wherein a portion of the interior of the sheath is filled with a non-conductive material. The second thermocouple is electrically coupled to the second metal sheath near the second end of the second mineral-insulated cable section.

2. The heat flux temperature sensor probe according to claim 1 further includes: At least one coupling portion of a thermocouple conductor of the same type from the first plurality of thermocouple conductors to the second plurality of thermocouple conductors.

3. The heat flux temperature sensor probe according to claim 1, wherein, The inorganic insulating material is magnesium oxide powder.

4. The heat flux temperature sensor probe according to claim 1, wherein, The inorganic insulating material is ceramic.

5. The heat flux temperature sensor probe according to claim 1, wherein, The sheath is made of metal.

6. The heat flux temperature sensor probe according to claim 5, wherein, The sheath is welded to at least one of the first mineral-insulated cable portion and the second mineral-insulated cable portion.

7. The heat flux temperature sensor probe according to claim 1, wherein, The sheath seals the non-conductive material within it.

8. The heat flux temperature sensor probe according to claim 7, wherein, The sheath includes a hole through which the non-conductive material is disposed, and then the hole is sealed after the disposal.

9. The heat flux temperature sensor probe according to claim 8, wherein, The hole was welded.

10. The heat flux temperature sensor probe according to claim 1, wherein, The number of the first plurality of thermocouple conductors is greater than the number of the second plurality of thermocouple conductors.

11. The heat flux temperature sensor probe according to claim 1, wherein, The inorganic insulating material is air.

12. A heat flux temperature sensor probe, comprising: A mineral-insulated cable having a metal sheath, a plurality of thermocouple conductors extending in the metal sheath, and an inorganic insulating material that insulates the plurality of thermocouple conductors from each other and from the metal sheath. A first thermocouple is formed between two of the plurality of thermocouple conductors at a junction where the metal sheath of the mineral-insulated cable is removed. A second thermocouple is formed between two of the plurality of thermocouple conductors near the end of the mineral-insulated cable; A sheath, operatively coupled to the mineral-insulated cable at the engagement location, wherein a portion of the interior of the sheath is filled with a non-conductive material, and The second thermocouple is electrically coupled to the metal sheath of the mineral-insulated cable at its end.

13. The heat flux temperature sensor probe according to claim 12, wherein, The interior portion of the sheath is filled with potting material.

14. The heat flux temperature sensor probe according to claim 13, wherein, The sheath is crimped to the mineral-insulated cable.

15. The heat flux temperature sensor probe according to claim 12, wherein, The sheath is welded to the mineral-insulated cable.

16. The heat flux temperature sensor probe of claim 12, wherein a third thermocouple is formed between two of the plurality of thermocouple conductors at the second joint position, wherein the metal sheath of the mineral-insulated cable is removed and covered with a second sheath at the second joint position.

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