Multi-temperature-zone measuring armored thermocouple and manufacturing method

Abstract

The application belongs to the technical field of thermocouples, and discloses an armored thermocouple for multi-temperature-zone measurement and a manufacturing method. The armored thermocouple comprises a sleeve, an insulating medium and a thermoelectric wire. The thermocouple forms a plurality of temperature measuring zones along the length direction. Each temperature measuring zone corresponds to at least one thermoelectric wire responsible for temperature measurement of the temperature measuring zone. The insulating medium is filled in the sleeve and separates the thermoelectric wires. The total length of the thermoelectric wires in different temperature measuring zones is in a decreasing trend from the hot end to the cold end of the thermocouple. The longer thermoelectric wire passes through the temperature measuring zone where the shorter thermoelectric wire is located. The application reasonably arranges the positions and lengths of the thermoelectric wires in different temperature measuring zones, integrates the thermoelectric wires in the sleeve after spacing the thermoelectric wires by the insulating medium, avoids space waste in the sleeve, increases the maximum allowable diameter of the thermoelectric wire, is more exquisite and compact in structure, has higher space utilization, has a deeper degree of diversification, and is more suitable for the work requirement of multi-temperature-zone measurement.

Description

Technical Field

[0001] This invention belongs to the field of thermocouple technology, specifically relating to a sheathed thermocouple for multi-temperature zone measurement and its manufacturing method. Background Technology

[0002] Diffusion furnaces or oxidation furnaces (heat processing equipment in the photovoltaic and semiconductor industries) are multi-temperature zone tube furnaces. Because of the multiple heating zones, each zone requires a matching thermocouple. For accurate temperature measurement, internal thermocouples are generally used. Figure 1 As shown, multiple thermocouples for detecting multiple temperature zones are bundled together and inserted axially along the inner wall of a tubular furnace to measure the temperature of the furnace. Multiple thermocouples of different lengths are assembled in a sheath. Each thermocouple has its own thermocouple wire, insulating medium, and protective sheath. The thermocouple wire is a pair of metal conductors that form the positive and negative poles of the thermocouple. When there is a temperature difference between the hot and cold ends of the thermocouple wire, a thermoelectric potential is generated in the circuit of the thermocouple wire. The magnitude of this electromotive force depends only on the properties of the conductor material and the temperature difference between the hot and cold ends.

[0003] The aforementioned structure results in low internal space utilization of the sheath because each thermocouple is cylindrical, leading to numerous gaps when assembled within a single tube. With the same amount of space, lower space utilization results in a smaller allowable diameter for the thermocouple wires, ultimately leading to a shorter thermocouple lifespan. Summary of the Invention

[0004] To address the issues of low internal space utilization and short service life in existing technologies for multi-point temperature measurement, In a first aspect, the present invention provides a sheathed thermocouple for multi-temperature zone measurement, comprising a sheath, an insulating medium and thermocouple wires, wherein the thermocouple forms several temperature measurement zones along its length, and each temperature measurement zone corresponds to at least one thermocouple wire responsible for measuring the temperature of that temperature measurement zone, and the insulating medium fills the inside of the sheath and separates the thermocouple wires. The total length of the thermocouple wires in different temperature measurement zones is such that the length of the thermocouple wires decreases from the hot end to the cold end. The longer dipole wire passes through the temperature measurement zone where the shorter dipole wire is located.

[0005] This invention avoids assembling multiple thermocouples in a sheath, but instead directly connects the thermocouples responsible for different temperature measurement zones. After the wires are separated by an insulating medium, they are integrated into the bushing. This avoids wasting space inside the bushing, increases the maximum allowable diameter of the wires, and also increases the number of wires to form more temperature measuring points. Of course, when needed, multiple thermocouples can be set up in the same temperature measurement area to measure the temperature. This can be done by comparing the data from multiple thermocouples to determine the accuracy of the temperature measurement, and also to meet the needs of multiple temperature control signals in certain scenarios.

[0006] In a second aspect, the present invention provides an intermediate for preparing a sheathed thermocouple for multi-temperature zone measurement in the first aspect, the intermediate comprising a sheath, an insulating post, and thermocouple wire; The insulating post is provided with a through hole for the passage of the coupling wire.

[0007] In this invention, the through holes on the insulating post are used to accommodate the coupling wires and determine the position of the coupling wires.

[0008] In some optional instances, the number of vias in a single insulating post is twice the total number of all the coupler wires.

[0009] In this invention, the number of through holes in all insulating posts is set to be the same. This can reduce the processing cost and improve the processing efficiency of insulating posts through mass production. At the same time, when assembling insulating posts and thermocouple wires, there is no need to distinguish them because the shape of the insulating posts is consistent. Of course, there are also some drawbacks. For example, the longest thermocouple wire is responsible for the temperature measurement of the farthest temperature measurement area. In this case, if only one thermocouple wire is needed for the temperature measurement area, then only two through holes need to be set in the insulating post (because the thermocouple wire needs to detour from the hot end to the cold end, so one thermocouple wire corresponds to two through holes). The extra through holes are not utilized. The lack of material at the through holes may cause problems after the thermocouple is drawn and formed, which brings a certain degree of uncertainty.

[0010] In some alternative instances, the number of through holes in the insulating pillars of different temperature measurement zones is different, and each through hole in the insulating pillar is traversed by a coupler wire.

[0011] In this invention, the through holes of the insulating post in each temperature measuring zone are designed to match the number of thermocouple wires that need to pass through. This avoids excess through holes, improves the density of the insulating medium, and prevents voids and excessive air, which is beneficial to improving the quality of the thermocouple. However, it also requires the production of insulating posts of different specifications, and during assembly, it is necessary to distinguish the insulating posts required for different temperature measuring zones.

[0012] Thirdly, the present invention provides a method for manufacturing a sheathed thermocouple for multi-temperature zone measurement as described in the first aspect, comprising the following: (I) Calculate the original length and diameter of the sleeve and thermocouple wire before they are pulled out, based on the thermocouple diameter, the required spacing between the temperature measuring points, and the distance between the temperature measuring points and the cold end; (II) Insert the coupling wire into the through hole of the insulating post; (III) Insert a non-porous insulating plug into the hot end of the bushing (the reason is that the end will become irregular and unusable during subsequent pulling, and on the other hand, oil may enter the end and it will also be unusable. Therefore, a non-porous insulating plug needs to be inserted as a redundant length that can be trimmed later), and put the assembly of the coupling wire and insulating post into the bushing. (IV) After the hot end is rolled into a tapered shape, it is repeatedly drawn and annealed until the dimensions after drawing meet the standards; (V) Locate the temperature measuring point by local heating or X-ray fluoroscopy, and cut off the excess length of the hot and cold ends; (VI) Hot end cap, cold end wiring and sealing.

[0013] The beneficial effects of this invention are: the reasonable arrangement of the positions and lengths of the thermocouple wires in different temperature measurement zones, and the integration of the thermocouple wires in the sleeve after being spaced by an insulating medium, avoids wasting space inside the sleeve and increases the maximum allowable diameter of the thermocouple wires; it is more sophisticated and compact in structure, has a higher space utilization rate, and the thermocouples are more diversified, making it more adaptable to the working needs of multi-temperature zone measurement. Attached Figure Description

[0014] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings; Figure 1 This is a schematic diagram of the existing technology; Figure 2 This is an external schematic diagram of the thermocouple in Embodiment 1 of the present invention; Figure 3 For Embodiment 1 of the present invention Figure 2 Sectional view of AA; Figure 4 For Embodiment 1 of the present invention Figure 2 Sectional view of BB; Figure 5 For Embodiment 1 of the present invention Figure 2 Sectional view of CC; Figure 6 For Embodiment 1 of the present invention Figure 2 Sectional view of DD; Figure 7 For Embodiment 1 of the present invention Figure 2 Sectional view of EE; Figure 8 For Embodiment 1 of the present invention Figure 2 Sectional view of FF; Figure 9 This is a schematic diagram of the insulating column corresponding to the insulating medium at FF in Embodiment 2 of the present invention; Figure 10 This is a schematic diagram showing the lengths of different couplers in Embodiment 1 of the present invention; The symbols for the main components are explained below: 1. Sleeve; 2. Insulating medium; 21. Via; 3. Even silk. Detailed Implementation

[0015] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein. Example

[0016] like Figures 2-10 As shown, this embodiment provides a multi-temperature zone measurement armored thermocouple, including a sheath 1, an insulating medium 2, and thermocouple wires 3. The thermocouple forms 6 temperature measurement zones along its length, and each temperature measurement zone corresponds to a thermocouple wire 3 responsible for measuring the temperature of that temperature measurement zone, for a total of 6 thermocouple wires 3. The insulating medium 2 fills the inside of the sheath 1 and separates the thermocouple wires 3. The total length of the thermocouple wire 3 in different temperature measurement zones is such that the length of the thermocouple wire 3 decreases from the hot end to the cold end. The longer dipole wire 3 passes through the temperature measurement zone where the shorter dipole wire 3 is located.

[0017] In this embodiment, because the temperature measuring zones are distributed in different locations, the length of the thermocouple 3 responsible for temperature measurement in each zone will also be different, such as... Figure 10 As shown, the longest length of the dipole wire 3 is the one furthest from the cold end, while the shortest length is the dipole wire 3 closest to the cold end. like Figure 2 As shown, a cross-sectional view of the six temperature measurement zones is presented, with the cross-sectional shapes displayed sequentially. Figures 3-8By observing the distribution of the dipole wire 3, it can be found that the longer dipole wire 3 passes through the temperature measurement area where the shorter dipole wire 3 is located. This is because the dipole wire 3 needs to return from the temperature measurement area to the cold end for wiring and to transmit the signal back. In the cross-sectional view shown by AA, since the temperature measurement area is farthest from the cold end, there is only one dipole wire 3. The figure shows two points because the dipole wire 3 needs to pass through the temperature measurement point and then detour back to the cold end. In the cross-sectional view shown by BB, in addition to the dipole wire 3 required by the temperature measurement area itself, it also needs to pass through the dipole wire 3 in the temperature measurement area where AA is located. Therefore, two dipole wires can be seen, and they are marked with different colors. The distribution principle of dipole wire 3 in the subsequent temperature measurement area is the same as the above principle, and will not be repeated here. In the above structure, the sleeve 1 is filled with an insulating medium 2 and the insulating medium 2 separates several thermocouple wires 3 to avoid mutual interference between the thermocouple wires 3. This makes full use of the space inside the sleeve 1, which increases the allowable diameter of the thermocouple wires 3 and allows the use of thermocouple wires 3 with larger cross-sectional areas, greatly improving the life of the thermocouple. In addition, the increase in available space can also be reflected in the increase in the number of thermocouple wires 3, which can provide more temperature measurement areas and meet the diverse needs of industrial temperature measurement. Compared to the existing technology that uses multiple thermocouples bundled together, the thermocouples in this embodiment are more sophisticated and compact in structure, have higher space utilization, and are more diverse, making them better suited to the needs of multi-temperature zone measurement. Example

[0018] This embodiment provides a manufacturing method for fabricating the armored thermocouple for multi-temperature zone measurement in Embodiment 1, including the following: (1) The thermocouple requires a diameter of 10mm and has a total of 6 temperature measurement zones. The distance from the temperature measurement point to the cold end in each temperature measurement zone is 4m, 3.5m, 3m, 2.5m, 2m, and 1.5m from farthest to near. The distance between each temperature measurement point is 0.5m. The original diameter of the sleeve 1 is 20mm and the length is 1.2m. The original diameter of the thermocouple wire 3 before being pulled is 2mm and the lengths are 1200mm, 1075mm, 950mm, 825mm, 700mm, and 575mm respectively. (2) Insert the 3-wire coupler into the through hole of the insulating post. Select an insulating post with an appropriate number of through holes 21 for different temperature measurement zones to avoid the situation where there are any remaining through holes 21. When inserting the through hole, you can first insert the insulating post with the fewest number of through holes 21, then insert the insulating post with the second-to-last number of through holes 21, and so on. For example, you can first insert the 1200mm long 3-wire coupler into the two-hole insulating post. When you get to the four-hole insulating post, add the 1075mm long 3-wire coupler into the four-hole insulating post and insert the 1200mm long 3-wire coupler into the four-hole insulating post. At this time, there are no remaining through holes 21 in the four-hole insulating post. Then insert the 1200mm long 3-wire coupler and the 1075mm long 3-wire coupler into the six-hole insulating post and add the 950mm long 3-wire coupler, and so on. Finally, insert all the 3-wire couplers into the twelve-hole insulating post. (3) Insert a non-porous insulating plug with a length of 100mm into the hot end of the sleeve 1, and put the assembly of the coupler wire 3 and the insulating column into the sleeve 1. (4) After the hot end is rolled into a diameter and then repeatedly drawn and annealed until the drawn thermocouple reaches the size standard. During the drawing process, the gas inside the sleeve 1 is discharged, the insulating column is broken and forms a dense insulating medium 2 to separate each thermocouple wire 3. (5) Locate the temperature measuring point by local heating and cut off the excess length of the hot and cold ends; (6) Hot end cap, cold end wiring and sealing.

[0019] The thermocouples fabricated in this embodiment were subjected to dimensional testing. Compared with conventional bundled thermocouples, the cross-sectional area of ​​the thermocouple wire 3 was increased by 5 times, thus extending the service life of the thermocouple.

[0020] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A sheathed thermocouple for multi-temperature zone measurement, comprising a sheath (1), an insulating medium (2), and thermocouple wires (3), characterized in that: The thermocouple forms several temperature measuring zones along its length, and each temperature measuring zone corresponds to at least one thermocouple wire (3) responsible for measuring the temperature of that temperature measuring zone. The insulating medium (2) fills the inside of the sleeve (1) and separates the thermocouple wire (3). The total length of the thermocouple wire (3) in different temperature measurement zones is such that the length of the thermocouple wire (3) decreases from the hot end to the cold end. The longer dipole (3) passes through the temperature measurement zone where the shorter dipole (3) is located.

2. An intermediate for preparing the armored thermocouple for multi-temperature zone measurement as described in claim 1, characterized in that: The intermediate body includes a sleeve (1), an insulating column, and a coupling wire (3). The insulating post is provided with a through hole (21) for the passage of the coupler wire (3).

3. An intermediate according to claim 2, characterized in that: The number of vias (21) in a single insulating post is twice the number of all the coupler wires (3).

4. An intermediate according to claim 2, characterized in that: The number of through holes (21) in the insulating pillars of different temperature measurement zones is different, and each through hole (21) in the insulating pillar is pierced by a coupler wire (3).

5. A method for manufacturing a sheathed thermocouple for multi-temperature zone measurement as described in claim 1, characterized in that: Includes the following: (I) Calculate the original length and diameter of the sleeve (1) and thermocouple wire (3) before they are pulled out, based on the thermocouple diameter, the required spacing between the temperature measuring points, and the distance between the temperature measuring points and the cold end; (II) Insert the coupler wire (3) through the hole in the insulating post; (Ⅲ) Insert a non-porous insulating plug into the hot end of the sleeve (1), and put the assembly of the coupler wire (3) and the insulating column into the sleeve (1); (IV) After the hot end is rolled into a tapered shape, it is repeatedly drawn and annealed until the dimensions after drawing meet the standards; (V) Locate the temperature measuring point by local heating or X-ray fluoroscopy, and cut off the excess length of the hot and cold ends; (VI) Hot end cap, cold end wiring and sealing.

Images