High-voltage-resistant shock-resistant double-layer sheathed thermocouple and manufacturing method thereof

Abstract

The invention provides a high-voltage-resistant shock-resistant double-layer sheathed thermocouple and a manufacturing method thereof, and the method comprises the steps: sequentially assembling a thermode insulating layer and an outer sleeve from the inside to the outside to form an assembly, carrying out the diameter reduction operation of the assembly for many times, enabling the outer diameter of the assembly to be sequentially increased from the hot end to the cold end, carrying out the heat treatment of the assembly, and carrying out the heat treatment of the assembly to obtain the high-voltage-resistant shock-resistant double-layer sheathed thermocouple. The armored thermocouple has the advantages that the performance of the armored thermocouple is ensured, the production efficiency is improved, the cost is reduced, the durability and the applicability of the thermocouple are enhanced, and the armored thermocouple has shorter thermal response time and more excellent leakage prevention, corrosion resistance and vibration resistance.

Description

Technical Field

[0001] The invention relates to the field of thermocouples, and in particular to a high-voltage and shock-resistant double-layer armored thermocouple and a manufacturing method thereof. Background Art

[0002] Thermocouples are commonly used temperature measuring elements in temperature measuring instruments. They work based on the principle of thermoelectric effect (also known as Seebeck effect). When two different conductors or semiconductors A and B form a loop and their two ends are connected to each other, as long as the temperatures at the two nodes are different, an electromotive force will be generated in the loop. The direction and magnitude of the electromotive force are related to the material of the conductor and the temperature of the two junctions. This phenomenon is called thermoelectric effect, and the loop composed of two conductors is called thermocouple. The high-pressure and shock-resistant double-layer armored thermocouple made according to the traditional single-layer armored thermocouple reduction process only performs simple drawing and reduction. There will be residual stress inside the thermocouple wire. At the same time, the microstructure will be destroyed during the drawing process, which is prone to problems such as broken thermocouple wire and cracking of the outer casing, making it difficult to meet the requirements. Summary of the invention

[0003] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a high-pressure resistant and shock-resistant double-layer armored thermocouple and a manufacturing method, which is used to solve the technical problems that the high-pressure resistant and shock-resistant double-layer armored thermocouple manufactured by the traditional single-layer armored thermocouple reduction process in the prior art only undergoes simple drawing and diameter reduction, and residual stress will exist inside the thermocouple wire. At the same time, the microstructure will also be destroyed during the drawing process, and the thermocouple wire is prone to breaking and the outer casing is prone to cracking.

[0004] To achieve the above-mentioned and other related purposes, the present invention provides a high-voltage and shock-resistant double-layer armored thermocouple and a manufacturing method thereof, comprising:

[0005] Assembling the hot electrode insulation layer and the outer sleeve in sequence from the inside to the outside to form an assembly;

[0006] Performing multiple diameter reduction operations on the assembly so that the outer diameters of the assembly increase from the hot end to the cold end;

[0007] heat treating the assembly;

[0008] The assembly after the heat treatment is processed and assembled.

[0009] The advantage of adopting the above technical solution is that while ensuring the performance of the armored thermocouple, it improves production efficiency, reduces costs, and enhances the durability and applicability of the thermocouple, with a faster thermal response time and better anti-leakage, anti-corrosion, and anti-vibration performance.

[0010] Optionally, the step of sequentially assembling the hot electrode insulation layer and the outer sleeve from the inside to the outside to form an assembly includes:

[0011] The hot end of the thermoelectrode is sealed and welded, an insulating layer is sheathed on the outside of the thermoelectrode, and the thermoelectrode sheathed with the insulating layer is inserted into the outer sheath.

[0012] Optionally, performing multiple diameter reduction operations on the assembly so that the outer diameters of the assembly increase sequentially from the hot end to the cold end includes:

[0013] The assembly is repeatedly cold-drawn so that the outer diameters of the hot electrode, the insulating layer and the outer sleeve of the assembly are reduced multiple times from the hot end to reach the expected outer diameter.

[0014] Optionally, the heat treatment of the assembly comprises:

[0015] Each time the assembly is drawn, a heat treatment is performed, and the time of each heat treatment varies according to the change of the drawn outer diameter, so as to enhance the mechanical strength and stability of the hot electrode, the insulating layer and the outer sleeve of the assembly.

[0016] Optionally, the processing and assembling of the assembly after the heat treatment comprises:

[0017] Use X-rays to detect the hot junction position of the thermode and mark it with lines. According to the required length and specifications, the armored thermocouple cable is accurately cut, and the hot end is sealed by argon arc welding or laser welding. The hot end is insulated and the wiring is performed at the cold end.

[0018] Optionally, the thickness of the outer sleeve is in the range of 1.3 mm to 1.4 mm.

[0019] Optionally, the diameter of the thermode is in the range of 0.2 mm to 0.3 mm.

[0020] Optionally, the length of the hot end seal of the thermode is in the range of 6-8 mm.

[0021] Optionally, the present application also discloses a high-voltage and shock-resistant double-layer armored thermocouple, which is manufactured according to the above-mentioned manufacturing method, and includes a thermocouple, an insulating layer and an outer sleeve, wherein the insulating layer is sleeved on the outside of the thermocouple, and the outer sleeve is sleeved on the outside of the insulating layer, and the outer diameter of the thermocouple increases successively from the hot end to the cold end.

[0022] Optionally, the insulating layer is a magnesium oxide insulating layer.

[0023] As described above, the high-pressure resistant and shock-resistant double-layer armored thermocouple and its manufacturing method of the present invention have the following beneficial effects: while ensuring the performance of the armored thermocouple, the production efficiency is improved, the cost is reduced, and the durability and applicability of the thermocouple are enhanced, and it has a faster thermal response time and better anti-leakage, anti-corrosion, and anti-vibration performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Shown is a process flow chart of a double-layer armored thermocouple in one embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the cross-sectional structure of the hot end of a double-layer armored thermocouple according to one embodiment of the present invention;

[0026] Figure 3 It is a schematic diagram of the radial cross-sectional structure of a double-layer armored thermocouple in one embodiment of the present invention;

[0027] Figure 4 Shown is a schematic diagram of the cold end cross-sectional structure of a double-layer armored thermocouple in one embodiment of the present invention.

[0028] Part Number Description

[0029] 1 Thermistor

[0030] 2 Insulation layer

[0031] 3 Outer casing DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] See also Figures 1 to 4It should be noted that the diagrams provided in the present embodiment only illustrate the basic concept of the present invention in a schematic manner. The diagrams only show the components related to the present invention rather than the number, shape and size of the components in the actual implementation. The type, quantity and proportion of each component during implementation can be changed at will, and the component layout type may also be more complicated. The structures, proportions, sizes, etc. shown in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Therefore, they have no technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of the relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0034] See also Figures 1 to 4 As shown, the present invention provides a high-voltage and shock-resistant double-layer armored thermocouple and a manufacturing method thereof, comprising:

[0035] Step S100: performing end-cap welding on the hot end of the thermode 1, sleeve an insulating layer 2 on the outside of the thermode 1, and inserting the thermode 1 sleeved with the insulating layer 2 into the outer sleeve 3;

[0036] Step S101: performing multiple diameter reduction treatments on the assembled hot electrode 1, and performing a heat treatment after each diameter reduction treatment;

[0037] Step S102: polishing the outer casing 3;

[0038] Step S103, inspecting the wall thickness, wire diameter, room temperature insulation resistance, electrical continuity, thermoelectromotive force tolerance, and appearance quality of the thermoelectrode 1;

[0039] Step S104: using X-rays to detect the hot junction position of the hot electrode 1, and marking it with lines;

[0040] Step S105: the armored thermocouple cable is precisely cut according to the required length and specification, and the hot end is sealed by argon arc welding or laser welding, and the hot end is insulated, and the cold end is wired.

[0041] Furthermore, during the heat treatment process, the protective gas is ammonia decomposition gas or nitrogen.

[0042] It should also be noted that by welding the hot end of the thermocouple and covering it with an insulating layer, the structural stability and good insulation performance of the thermocouple are ensured. This helps prevent current leakage and degradation of the thermocouple performance;

[0043] Multiple diameter reduction and heat treatment processes help to enhance the mechanical strength and stability of the thermocouple, while reducing the dimensional changes caused by temperature changes, thereby improving the measurement accuracy and durability of the thermocouple. Heat treatment can improve its mechanical properties and damage resistance by eliminating the residual stress inside the wire and improving its microstructure. It can eliminate the residual stress inside the casing material and improve its organizational uniformity, thereby improving its crack resistance.

[0044] Polishing the outer sleeve not only improves the appearance quality of the thermocouple, but also reduces the loss caused by friction during use and prolongs the service life of the thermocouple.

[0045] During the manufacturing process, multiple key parameters of the thermocouple are checked, such as wall thickness, wire diameter, room temperature insulation resistance, electrical continuity, thermoelectric potential tolerance and appearance quality, to ensure that the performance of the thermocouple meets the design requirements.

[0046] Using X-rays to detect and mark the hot junctions helps to accurately locate the hot junctions of thermocouples during installation and use, improving the accuracy and reliability of measurements.

[0047] The armored thermocouple cable is precisely cut according to the required length and specifications, and the hot end is sealed using advanced welding methods to meet the needs of different application scenarios. At the same time, the insulation and wiring treatments ensure the safety and reliability of the thermocouple during use.

[0048] The entire manufacturing process has clear steps and rigorous logic. By optimizing process parameters and process control, production efficiency and product quality are improved and manufacturing costs are reduced.

[0049] Exemplarily, the high-pressure and shock-resistant double-layer armored thermocouple is reduced in diameter in the order of φ11.5mm, φ10.8mm, φ10.0mm, φ9.3mm, φ8.5mm, φ8.0mm, φ7.4mm, φ6.9mm, φ6.4mm and φ6.0mm.

[0050] It should also be noted that the diameter reduction process can reduce the heat capacity of the thermocouple, making it respond faster to the measured temperature and able to reflect temperature changes more quickly. By gradually reducing the diameter of the thermocouple, the structure can be made more compact. At the same time, the mechanical strength of the thermocouple is enhanced to a certain extent, and its ability to resist external mechanical shock and vibration is improved. The diameter reduction process helps to improve the thermoelectric performance of the thermocouple and make it have higher measurement accuracy and stability. Because the hot end of the thermocouple is smaller after the diameter reduction, the temperature change in a small range can be measured more accurately, the production process can be optimized, the scrap rate can be reduced, and the cost can be reduced. At the same time, this orderly diameter reduction process also helps to maintain the consistency and reliability of the thermocouple.

[0051] For example, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ11.5mm is 260mm / min, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ10.8mm is 300mm / min, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ10 is 310mm / min, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ9.3mm is 350mm / min, and the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ8.5mm is 380mm / min. m / min, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ8 is 410mm / min, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ7.4mm is 440mm / min, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ6.9mm is 470mm / min, the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ6.4mm is 500mm / min, and the annealing speed of the high-pressure shock-resistant double-layer armored thermocouple reduced to φ6 is 318mm / min.

[0052] It should also be noted that by precisely controlling the annealing speed, the organizational structure of the thermocouple material can be optimized to make it more uniform and dense. The annealing treatment can improve the mechanical properties and oxidation resistance of the thermocouple material, reduce oxidation and corrosion in high temperature environments, and thus extend the service life of the thermocouple. The residual stress and non-uniformity inside the thermocouple material can improve the measurement accuracy, so that it can more accurately reflect the changes in the measured temperature;

[0053] Annealing treatment can improve the mechanical properties and oxidation resistance of thermocouple materials, reduce oxidation and corrosion in high temperature environments, and thus extend the service life of thermocouples;

[0054] The annealing speed increases from φ11.5mm to φ10.8mm: As the diameter of the thermocouple decreases, the annealing speed gradually increases. This is because the smaller diameter thermocouple has a larger surface area and faster heat transfer rate, so a faster annealing speed is required to maintain the uniformity and stability of the material.

[0055] The annealing speed of φ10 to φ6.9 mm continues to increase: within this range, the annealing speed continues to increase to accommodate the further reduction in thermocouple diameter and changes in material properties. This increase in speed helps ensure that the material is fully processed and optimized during the annealing process.

[0056] The annealing speed of φ6.4mm to φ6 is reduced: when the thermocouple diameter is reduced to below φ6.4mm, the annealing speed is reduced. This is because within this range, the heat transfer rate and recrystallization rate of the material have changed, and the annealing speed needs to be adjusted to maintain the best annealing effect.

[0057] Exemplarily, the thickness of the outer sleeve ranges from 1.3 mm to 1.4 mm.

[0058] Exemplarily, the diameter of the thermode 1 ranges from 0.2 mm to 0.3 mm.

[0059] Exemplarily, the length of the hot end seal of the thermode 1 is in the range of 6-8 mm.

[0060] Exemplarily, the hot end of the thermode 1 is first welded, then inserted into the insulating layer 2 , and finally inserted into the outer sleeve 3 .

[0061] Exemplarily, a high-voltage shock-resistant double-layer armored thermocouple is manufactured according to the above-mentioned manufacturing method, including a thermode 1, an insulating layer 2 and an outer sleeve 3, wherein the insulating layer 2 is sleeved on the outside of the thermode 1, and the outer sleeve 3 is sleeved on the outside of the insulating layer 2. The outer diameter of the high-voltage shock-resistant double-layer armored thermocouple increases from the hot end to the cold end.

[0062] It should also be noted that the outer diameter of the high-pressure and shock-resistant double-layer armored thermocouple gradually increases from the hot end to the cold end. This design enhances the overall structural strength of the thermocouple, especially in high-pressure environments. It can better resist external pressure and prevent the thermocouple from being damaged by pressure. The gradually increasing outer diameter design helps to disperse and alleviate the impact of vibration on the thermocouple and improves the shock resistance of the thermocouple. In an environment with large vibrations, this design can ensure the stability and accuracy of the thermocouple. Although the gradual increase in the outer diameter is not directly for optimizing heat conduction, this design helps to form a more uniform temperature gradient inside the thermocouple. This helps the thermocouple measure temperature more accurately and reduce errors caused by uneven temperature gradients, adapting to a wider range of application scenarios.

[0063] Exemplarily, the insulating layer is a magnesium oxide insulating layer.

[0064] It should also be noted that magnesium oxide has a very high dielectric strength, which is much higher than that of general organic materials and can reach more than 500kV / mm. This enables magnesium oxide to effectively prevent current leakage and ensure the accuracy of thermocouple measurements. At the same time, the dielectric loss of magnesium oxide is very small, and it can maintain a good insulation effect even in a high-frequency electric field, which helps to reduce energy loss and improve the energy efficiency of thermocouples. Magnesium oxide has good chemical stability and can resist erosion by corrosive media such as acids and alkalis. This enables the magnesium oxide insulation layer to maintain its performance stability in harsh chemical environments and extend the service life of thermocouples.

[0065] Exemplarily, the outer sleeve 3 is made of metal.

[0066] It should also be noted that the outer sleeve 3 is made of nickel alloy or titanium alloy. Nickel alloy has excellent oxidation resistance and corrosion resistance and can be used at higher temperatures. Titanium alloy has excellent corrosion resistance and high temperature resistance and is particularly suitable for temperature measurement in acidic and alkaline environments.

[0067] In summary, the high-pressure resistant and shock-resistant double-layer armored thermocouple and its manufacturing method of the present invention can improve production efficiency, reduce costs, and enhance the durability and applicability of the thermocouple while ensuring the performance of the armored thermocouple, and have a faster thermal response time and better anti-leakage, anti-corrosion, and anti-vibration performance.

[0068] The outer diameter, wall thickness and wire diameter of the high-pressure and shock-resistant double-layer armored thermocouple manufactured in accordance with the present application can meet the technical requirements (the outer tube wall thickness is measured to be 1.22mm, the wire diameter is 0.4mm, the outer diameter of the outer armor material is φ6.0mm, and the outer diameter of the inner armor material is φ2.2mm). The results show that the wall thickness, wire diameter, appearance and other properties of the developed high-pressure and shock-resistant double-layer armored thermocouple meet the drawings and GB / T18404-2022 armored thermocouple cable and armored thermocouple standard requirements.

[0069] The room temperature and high temperature insulation resistance of the high voltage and earthquake resistant double-layer armored thermocouple samples were tested using a 500V insulation resistance meter. The test results are shown in Table 1: Insulation resistance test results of the high voltage and earthquake resistant double-layer armored thermocouple samples.

[0070] Table 1 Insulation resistance test results of high voltage and shock resistant double-layer armored thermocouple samples

[0071] Serial number Test temperature ℃ <![CDATA[Insulation resistance MΩ ·m]]> Standard Detection results 1 Room temperature ∞ ≥10000 qualified 2 100 ∞ -- -- 3 200 ∞ -- -- 4 300 ∞ ≥300 qualified 5 450 750 -- -- 6 500 300 ≥15 qualified 7 800 0.5 ≥0.5 qualified

[0072] The test results are shown in Table 1. The insulation resistance in the range of room temperature to 300°C is infinite. As the test temperature increases further, the insulation resistance gradually decreases, dropping to 750MΩ.m at 450°C and 300MΩ.m at 500°C, which is much higher than the lower limit of 15MΩ.m required by the standard. The results show that the insulation resistance of the high-voltage and shock-resistant double-layer armored thermocouple samples at room temperature, 300°C, 500°C and 800°C meets the requirements of standard GB / T 18404-2022.

[0073] Vibration tests were carried out on high-voltage and shock-resistant double-layer armored thermocouple samples and single-layer armored thermocouple samples of the same specification for comparison. The vibration test process and RT test results showed that when the acceleration was 6g and the resonance frequency was vibrated, the bottom and middle section of the inner core of the high-voltage and shock-resistant double-layer thermocouple and the single-layer armored thermocouple were severely worn. However, the RT ray and conduction test results showed that the hot contacts and couple materials were intact.

[0074] The thermal response time τ 0.632 of the Φ6 high-pressure and shock-resistant double-layer armored thermocouple was tested using a constant temperature water tank, as shown in Table 2: The response time test results of the traditional single-layer armored thermocouple, the measured thermal response time was 2.00s and 2.01s. Compared with the response time of the traditional single-layer armored thermocouple of the same specification (whose thermal response time is distributed in the range of 2.40s to 4.98s), it was found that the difference between the two results was not large, and the thermal response time of the present application was slightly better than that of the traditional single-layer armored thermocouple.

[0075] Table 2 Response time test results of traditional single-layer armored thermocouple

[0076]

[0077] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple, characterized in that: include: Assembling the hot electrode insulation layer and the outer sleeve in sequence from the inside to the outside to form an assembly; Performing multiple diameter reduction operations on the assembly so that the outer diameters of the assembly increase from the hot end to the cold end; heat treating the assembly; The assembly after the heat treatment is processed and assembled.

2. The method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple according to claim 1, characterized in that: The hot electrode insulation layer and the outer sleeve are assembled in sequence from the inside to the outside to form an assembly, comprising: The hot end of the thermoelectrode is sealed and welded, an insulating layer is sheathed on the outside of the thermoelectrode, and the thermoelectrode sheathed with the insulating layer is inserted into the outer sheath.

3. The method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple according to claim 2, characterized in that: The step of performing multiple diameter reduction operations on the assembly so that the outer diameters of the assembly increase from the hot end to the cold end, comprises: The assembly is repeatedly cold-drawn so that the outer diameters of the hot electrode, the insulating layer and the outer sleeve of the assembly are reduced multiple times from the hot end to reach the expected outer diameter.

4. The method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple according to claim 3, characterized in that: The step of heat treating the assembly comprises: Each time the assembly is drawn, a heat treatment is performed, and the time of each heat treatment varies according to the change of the drawn outer diameter, so as to enhance the mechanical strength and stability of the hot electrode, the insulating layer and the outer sleeve of the assembly.

5. The method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple according to claim 4, characterized in that: The step of processing and assembling the assembly after the heat treatment comprises: Use X-rays to detect the hot junction position of the thermode and mark it with lines. According to the required length and specifications, the armored thermocouple cable is accurately cut, and the hot end is sealed by argon arc welding or laser welding. The hot end is insulated and the wiring is performed at the cold end.

6. The method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple according to claim 5, characterized in that: The thickness of the outer sleeve is in the range of 1.3 mm to 1.4 mm.

7. The method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple according to claim 6, characterized in that: The diameter of the thermode is in the range of 0.2 mm to 0.3 mm.

8. The method for manufacturing a high-voltage and shock-resistant double-layer armored thermocouple according to claim 7, characterized in that: The length of the hot end sealing head of the thermoelectrode is in the range of 6-8 mm.

9. A high-voltage and earthquake-resistant double-layer armored thermocouple, manufactured according to the method for manufacturing a high-voltage and earthquake-resistant double-layer armored thermocouple according to any one of claims 1 to 8, comprising a thermode, an insulating layer and an outer sleeve, the insulating layer being sleeved on the outside of the thermode, the outer sleeve being sleeved on the outside of the insulating layer, and the outer diameter of the thermode increasing from the hot end to the cold end.

10. The high-voltage and shock-resistant double-layer armored thermocouple according to claim 9, characterized in that: The insulating layer is a magnesium oxide insulating layer.

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