High-temperature-resistant ceramic composite thermocouple protective sleeve

Abstract

The high-temperature-resistant ceramic composite thermocouple protective sleeve comprises a protective tube body, the protective tube body comprises a protective tube outer layer, a protective tube middle layer and a protective tube inner layer which are sequentially arranged from outside to inside, and the protective tube outer layer is formed by compounding a mullite ceramic layer and a high-temperature-resistant anti-oxidation coating coated on the mullite ceramic layer. The outer surface of the non-measuring end of the protective tube outer layer is further provided with a wear-resistant protrusion, the inner wall of the protective tube inner layer is provided with a spiral groove, the bottom end of the protective tube inner layer is in threaded connection with a sealing end cover, and the sealing end cover and the bottom end of the protective tube body are fixedly sealed through high-temperature-resistant sealant. The protective sleeve solves the problems that an existing protective sleeve is easy to damage in a high-temperature environment, low in heat conduction efficiency and the like through the optimal design of the structure and the material.

Description

Technical Field

[0001] This utility model relates to the field of thermocouple protection tube technology, specifically to a high-temperature resistant ceramic composite thermocouple protection sleeve. Background Technology

[0002] In high-temperature industrial production processes, thermocouples are commonly used temperature measuring elements, and the performance of their protective sheaths is crucial to measurement accuracy and service life. Currently, although traditional metal protective sheaths have a certain mechanical strength, they are prone to oxidation and corrosion in high-temperature environments, leading to sheath damage and affecting the normal operation of the thermocouple. While single ceramic protective sheaths have good high-temperature resistance, they have poor toughness and are prone to cracking and breaking when subjected to mechanical impact or sudden temperature changes, failing to meet the needs of complex working conditions. In addition, the existing protective sheaths have low thermal conductivity, resulting in long thermocouple response times and difficulty in quickly and accurately reflecting the actual temperature of the measured medium. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a high-temperature resistant ceramic composite thermocouple protection sleeve. Through optimized design of structure and materials, it solves the problems of easy damage and low heat conduction efficiency of existing protection sleeves in high-temperature environments.

[0004] The technical solution adopted in this utility model is a high-temperature resistant ceramic composite thermocouple protection sleeve, including a protection tube body. The protection tube body includes an outer protection tube layer, a middle protection tube layer, and an inner protection tube layer arranged sequentially from the outside to the inside. The outer surface of the non-measuring end of the outer protection tube layer is provided with wear-resistant protrusions. The inner wall of the inner protection tube layer is provided with a spiral groove. A sealing end cap is threadedly connected to the bottom end of the inner protection tube layer. The sealing end cap is fixed and sealed to the bottom end of the protection tube body by high-temperature resistant sealant.

[0005] The outer layer, middle layer, and inner layer of the protective tube are a high-temperature sintered composite integrated structure.

[0006] The outer layer of the protective tube is composed of a mullite ceramic layer and a high-temperature resistant and antioxidant coating applied to the mullite ceramic layer.

[0007] The middle layer of the protective tube is a composite structure of nickel-based alloy and silicon carbide particles, wherein the volume fraction of silicon carbide particles is 10%-30%.

[0008] The inner layer of the protective tube is an alumina ceramic structure.

[0009] The depth of the spiral groove is 0.5-2mm, and the pitch is 3-8mm.

[0010] The thickness of the high-temperature resistant and antioxidant coating is 0.01-0.1 mm.

[0011] The beneficial effects of this utility model are as follows: In this utility model, the protective tube body is composed of an outer protective tube layer, a middle protective tube layer, and an inner protective tube layer, which are sintered together at high temperature. The outer protective tube layer is composed of a mullite ceramic layer and a high-temperature resistant and anti-oxidation coating, which has the ability to resist high temperature, corrosion, and oxidation, thus solving the problem that traditional metal protective sleeves are prone to oxidation and corrosion. The middle protective tube layer is composed of a nickel-based alloy and silicon carbide particles, which has certain mechanical strength and good thermal conductivity, thus solving the problem that although single ceramic protective sleeves have good high-temperature resistance, they have poor toughness and are prone to cracking and breaking when subjected to mechanical impact or sudden temperature changes. The inner protective tube layer is made of alumina ceramic material, which has excellent high-temperature resistance and chemical stability. In addition, a spiral groove is provided on the inner protective tube layer. The spiral groove increases the contact area, promotes heat convection, and optimizes the thermal resistance distribution, thus solving the problem that the existing protective sleeves have low thermal conductivity, resulting in long thermocouple response time and difficulty in quickly and accurately reflecting the actual temperature of the measured medium.

[0012] In this invention, the sealing end cap and high-temperature resistant sealant are used together to ensure the sealing of the inside of the protective tube body, which can prevent high-temperature media from entering the inside of the protective tube body and affecting the normal operation of the thermocouple.

[0013] In this invention, wear-resistant protrusions are provided on the non-measuring end of the outer layer of the protective tube. This increases the hardness and wear resistance of the part, extends the service life of the protective tube body, increases the surface area, promotes heat convection, and helps dissipate the heat inside the protective tube body, thus playing a certain role in heat dissipation.

[0014] In this invention, the composite structure design of the outer layer, middle layer and inner layer of the protective tube achieves an organic combination of properties such as high temperature resistance, corrosion resistance and high toughness, which significantly improves the overall performance of the protective sleeve and enables it to adapt to various harsh working conditions. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the overall structure of this utility model.

[0016] Figure 2 This is a schematic diagram of the outer structure of the protective tube of this utility model.

[0017] Figure 3 This is a front view schematic diagram of the wear-resistant protrusions and the outer layer of the protective tube of this utility model.

[0018] In the diagram: 1. Sealed end cap, 2. High-temperature resistant sealant, 3. Outer protective tube layer, 4. Middle protective tube layer, 5. Inner protective tube layer, 6. Spiral groove, 7. Wear-resistant protrusion, 8. High-temperature resistant and antioxidant coating, 9. Mullite ceramic layer. Detailed Implementation

[0019] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0020] Referring to the attached drawings, a high-temperature resistant ceramic composite thermocouple protective sleeve includes a protective tube body. The protective tube body includes an outer protective tube layer 3, a middle protective tube layer 4, and an inner protective tube layer 5 arranged sequentially from the outside to the inside. The outer surface of the non-measuring end of the outer protective tube layer 3 is provided with wear-resistant protrusions 7. The inner wall of the inner protective tube layer 5 is provided with a spiral groove 6. A sealing end cap 1 is threadedly connected to the bottom end of the inner protective tube layer 5. The sealing end cap 1 is fixed and sealed to the bottom end of the protective tube body by a high-temperature resistant sealant 2.

[0021] The outer layer 3, the middle layer 4, and the inner layer 5 of the protective tube are a high-temperature sintered composite integrated structure.

[0022] The outer layer 3 of the protective tube is composed of a mullite ceramic layer 9 and a high-temperature resistant and antioxidant coating 8 coated on the mullite ceramic layer 9.

[0023] The protective tube intermediate layer 4 is a composite structure of nickel-based alloy and silicon carbide particles, wherein the volume fraction of silicon carbide particles is 10%-30%.

[0024] The inner layer 5 of the protective tube is an alumina ceramic structure.

[0025] The spiral groove 6 has a depth of 0.5-2mm and a pitch of 3-8mm.

[0026] The thickness of the high-temperature resistant and antioxidant coating 8 is 0.01-0.1 mm.

[0027] When using this high-temperature resistant ceramic composite thermocouple protection sleeve, the assembled protection tube body is placed on the thermocouple, allowing it to penetrate into the high-temperature measured medium for temperature measurement. During the measurement process, the heat of the high-temperature measured medium is transferred through the outer layer 3 and the middle layer 4 of the protection tube to the inner layer 5, and then conducted to the thermocouple wire, achieving accurate temperature measurement.

[0028] During heat transfer, the spiral groove 6 alters the heat transfer path, creating a spiral-like upward flow path that facilitates thermal convection. This convection accelerates heat transfer between the inner layer 5 of the protective tube and the thermocouple wire, improving thermal conductivity. Simultaneously, the presence of the spiral groove 6 makes the thermal resistance distribution of the inner layer 5 of the protective tube more uniform, preventing excessive local thermal resistance from causing heat accumulation. This allows heat to be transferred more smoothly from the high-temperature region (the measured medium) to the low-temperature region (the thermocouple wire), thereby enhancing the overall thermal conductivity.

[0029] In this invention, the protective tube body is composed of an outer protective tube layer 3, a middle protective tube layer 4, and an inner protective tube layer 5, all sintered at high temperatures. The outer protective tube layer 3 is composed of a mullite ceramic layer 9 and a high-temperature resistant and oxidation-resistant coating 8, providing high-temperature resistance, corrosion resistance, and oxidation resistance, thus solving the problem of oxidation and corrosion in traditional metal protective sleeves. The middle protective tube layer 4 is composed of a nickel-based alloy and silicon carbide particles, possessing certain mechanical strength and good thermal conductivity, thus solving the problem that while single ceramic protective sleeves have good high-temperature resistance, they lack toughness and are prone to cracking and breakage under mechanical impact or sudden temperature changes. The inner protective tube layer 5 is made of alumina ceramic material, possessing excellent high-temperature resistance and chemical stability. Furthermore, the inner protective tube layer 5 is provided with a spiral groove 6, which increases the contact area, promotes heat convection, and optimizes thermal resistance distribution, thus solving the problem of low thermal conductivity in existing protective sleeves, resulting in long thermocouple response times and difficulty in quickly and accurately reflecting the actual temperature of the measured medium.

[0030] In this invention, the sealing end cap 1 and the high-temperature resistant sealant 2 work together to ensure the sealing of the inside of the protective tube body, preventing high-temperature media from entering the inside of the protective tube body and affecting the normal operation of the thermocouple.

[0031] In this invention, wear-resistant protrusions 7 are provided on the non-measuring end of the outer layer 3 of the protective tube. This can increase the hardness and wear resistance of this part, extend the service life of the protective tube body, increase the surface area, promote heat convection, and help dissipate the heat inside the protective tube body, thus playing a certain heat dissipation role.

[0032] In this invention, the composite structure design of the outer protective tube 3, the middle protective tube 4, and the inner protective tube 5 achieves an organic combination of properties such as high temperature resistance, corrosion resistance, and high toughness, significantly improving the overall performance of the protective sleeve and enabling it to adapt to various harsh working conditions.

[0033] The above-described embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A high-temperature resistant ceramic composite thermocouple protection sleeve, comprising a protection tube body, characterized in that: The protective tube body includes an outer protective tube layer (3), a middle protective tube layer (4), and an inner protective tube layer (5) arranged sequentially from the outside to the inside. The outer surface of the non-measuring end of the outer protective tube layer (3) is provided with wear-resistant protrusions (7). The inner wall of the inner protective tube layer (5) is provided with spiral grooves (6). The bottom end of the inner protective tube layer (5) is threaded with a sealing end cap (1). The sealing end cap (1) is fixed and sealed to the bottom end of the protective tube body by high-temperature resistant sealant (2).

2. The high-temperature resistant ceramic composite thermocouple protection sleeve according to claim 1, characterized in that: The outer layer (3), middle layer (4), and inner layer (5) of the protective tube are high-temperature sintered composite integrated structures.

3. The high-temperature resistant ceramic composite thermocouple protection sleeve according to claim 1, characterized in that: The outer layer (3) of the protective tube is composed of a mullite ceramic layer (9) and a high-temperature resistant and antioxidant coating (8) applied to the mullite ceramic layer (9).

4. The high-temperature resistant ceramic composite thermocouple protection sleeve according to claim 1, characterized in that: The inner layer (5) of the protective tube is an alumina ceramic structure.

5. The high-temperature resistant ceramic composite thermocouple protection sleeve according to claim 1, characterized in that: The spiral groove (6) has a depth of 0.5-2 mm and a pitch of 3-8 mm.

6. The high-temperature resistant ceramic composite thermocouple protection sleeve according to claim 3, characterized in that: The thickness of the high-temperature resistant and antioxidant coating (8) is 0.01-0.1 mm.

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