A protective structure for a high-temperature resistant capacitive liquid level sensor
By employing a multi-layer protective structure consisting of a rhenium alloy supporting conductive layer, an alumina heat insulation layer, and a molybdenum disilicide outer layer in a high-temperature capacitive liquid level sensor, the problem of electrode material performance degradation under high-temperature conditions is solved, achieving high-precision liquid level detection and sensor stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI QIANLEI MACHINERY CO LTD
- Filing Date
- 2025-07-08
- Publication Date
- 2026-07-03
AI Technical Summary
Existing high-temperature capacitive liquid level sensors are prone to degradation of electrode material performance in high-temperature environments, affecting detection accuracy and sensitivity. At the same time, internal circuits are prone to failure, making it impossible to stably convert liquid level changes into electrical signals.
It adopts a multi-layer protective structure consisting of a supporting conductive layer, a heat insulation layer, and an outer layer. The supporting conductive layer uses rhenium alloy as the electrode conductor to conduct heat, the heat insulation layer uses aluminum oxide to reduce heat transfer, and the outer layer uses molybdenum disilicide to resist corrosion. Combined with heat sinks, it provides all-round protection.
It improves the accuracy and sensitivity of liquid level detection, extends the service life of the sensor, ensures stable operation in high-temperature environments, and prevents degradation of electrode material performance and damage to internal circuits.
Smart Images
Figure CN224455916U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of liquid level sensor technology, and in particular to a protective structure for a high-temperature resistant capacitive liquid level sensor. Background Technology
[0002] In high-temperature industrial production fields such as chemical, metallurgical, and energy industries, accurate and stable monitoring of the liquid level within containers is crucial. High-temperature resistant capacitive level sensors, as measuring devices that convert liquid level changes into electrical signals, have become key components for achieving industrial automation and safety monitoring due to their high precision and non-contact measurement characteristics. They reflect liquid level conditions by detecting changes in capacitance, and their reliable operation in high-temperature and complex environments directly affects the continuity and stability of industrial production.
[0003] Currently, most high-temperature capacitive liquid level sensors on the market employ traditional electrode structures and thermal insulation designs. Mechanically, they typically consist of a metal electrode probe, an insulating layer, and an outer protective shell, with the electrode probe directly inserted into the liquid being measured. Their technical principle is based on capacitance changes; when the liquid level changes, the capacitance between the electrode and the liquid changes accordingly, and the liquid level is determined by measuring this capacitance. For thermal insulation, insulating material is generally filled between the outer shell and the internal circuitry to reduce the impact of external high temperatures on the internal circuitry.
[0004] However, in practical applications, existing high-temperature capacitive liquid level sensors suffer from problems because the metal electrode probes must both detect changes in liquid level and operate in high-temperature environments. During heat conduction, the performance of the electrode materials is easily degraded, affecting the accuracy and sensitivity of liquid level detection. Furthermore, heat conduction can cause internal circuits to malfunction due to excessive temperature, making it impossible to stably and accurately convert changes in liquid level into electrical signals. Therefore, a protective structure for high-temperature capacitive liquid level sensors is proposed to address these issues. Utility Model Content
[0005] To overcome the above shortcomings, this utility model provides a high-temperature resistant capacitive liquid level sensor protection structure, which aims to improve the problem that in the prior art, the performance of the probe electrode material is easily degraded during the heat conduction process, affecting the detection accuracy and sensitivity of liquid level changes.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A protective structure for a high-temperature resistant capacitive liquid level sensor includes a sensor body, an mounting plate fixedly connected to the lower surface of the sensor body, a probe fixedly connected to the bottom of the mounting plate, a protective component provided on the side wall of the probe, and a fixing component provided inside the mounting plate.
[0008] The protective assembly includes a protective cover, the sidewall of which is slidably connected to the sidewall of the probe rod, a connecting plate fixedly connected to the sidewall of the protective cover, a heat sink fixedly connected to the sidewall of the protective cover, a supporting conductive layer disposed inside the protective cover, the sidewall of the supporting conductive layer being attached to the sidewall of the probe rod, a heat insulation layer disposed on the sidewall of the supporting conductive layer, and an outer layer disposed on the sidewall of the heat insulation layer.
[0009] As a further description of the above technical solution:
[0010] The fixing component includes a mounting shell, the sidewall of which is slidably connected to the mounting plate and the connecting plate, and a tapered head is fixedly connected to the sidewall of the mounting shell.
[0011] As a further description of the above technical solution:
[0012] The supporting conductive layer is made of rhenium alloy and serves as the electrode conductor for capacitance detection. It also helps to quickly conduct the heat generated inside the probe rod away, avoiding local overheating. The heat insulation layer is made of alumina and serves to insulate against heat, reducing heat transfer to the probe rod and minimizing the thermal impact. The outer layer is made of molybdenum disilicide and is used to resist acid erosion and corrosion.
[0013] As a further description of the above technical solution:
[0014] A pull ring is fixedly connected to the side wall of the mounting housing, and a locking block is threadedly connected to the side wall of the mounting housing. The side wall of the locking block is attached to the upper surface of the mounting plate.
[0015] As a further description of the above technical solution:
[0016] A pressing rod is slidably connected inside the mounting housing, and a fixing rod is fixedly connected to the lower surface of the pressing rod.
[0017] As a further description of the above technical solution:
[0018] A spring is fitted on the side wall of the fixing rod. One end of the spring is fixedly connected to the inside of the conical head, and the other end of the spring is fixedly connected to the lower surface of the pressing rod.
[0019] As a further description of the above technical solution:
[0020] A fixing block is fixedly connected to the side wall of the pressing rod, and the side wall of the fixing block is slidably connected inside the mounting shell.
[0021] As a further description of the above technical solution:
[0022] The side wall of the fixed block is rotatably connected to a support rod, and the side wall of the support rod is attached to the lower surface of the connecting plate.
[0023] This utility model has the following beneficial effects:
[0024] 1. In this utility model, a supporting conductive layer is used as an electrode to detect changes in liquid level while simultaneously conducting internal heat. A heat insulation layer blocks external high temperatures, protecting the internal circuitry of the probe. The outer layer resists high-temperature oxidation and acid corrosion, extending the lifespan of the protective structure. The heat sink continuously dissipates heat, maintaining overall temperature balance. This solves the problem that some high-temperature capacitive liquid level sensors are prone to deterioration of the probe electrode material's performance during heat conduction, affecting their accuracy and sensitivity in detecting changes in liquid level. The above structure improves the protection effect on the probe.
[0025] 2. In this utility model, by pulling the ring and pressing the pressing rod, the spring is compressed and the fixed block slides to retract the support rod. The mounting shell is inserted into the corresponding hole of the mounting plate and the connecting plate. The conical head is used to achieve quick positioning. Then, the pressing rod is released, the spring rebounds, and the support rod connected by rotation is opened outward to make it fit tightly against the lower surface of the connecting plate, ensuring that the protective cover is firmly connected to the mounting plate. Then, the locking block is rotated by the thread to press it against the upper surface of the mounting plate, realizing the quick installation and removal of the protective cover. Attached Figure Description
[0026] Figure 1 This is a three-dimensional schematic diagram of a high-temperature resistant capacitive liquid level sensor protection structure proposed in this utility model.
[0027] Figure 2 This is a schematic diagram of the protective cover for a high-temperature resistant capacitive liquid level sensor protective structure proposed in this utility model;
[0028] Figure 3 This is a schematic diagram of the protective component of a high-temperature resistant capacitive liquid level sensor protective structure proposed in this utility model;
[0029] Figure 4 for Figure 3 Enlarged view of point A in the middle;
[0030] Figure 5 This is a schematic diagram of the mounting shell of a high-temperature resistant capacitive liquid level sensor protective structure proposed in this utility model.
[0031] Figure 6 This is a schematic diagram of the internal structure of the mounting shell of the protective structure for a high-temperature resistant capacitive liquid level sensor proposed in this utility model.
[0032] Legend:
[0033] 1. Sensor body; 2. Mounting plate; 3. Probe rod; 4. Protective cover; 5. Heat sink; 6. Supporting conductive layer; 7. Heat insulation layer; 8. Outer layer; 9. Connecting plate; 10. Mounting shell; 11. Pull ring; 12. Locking block; 13. Pressing rod; 14. Conical head; 15. Fixing block; 16. Support rod; 17. Fixing rod; 18. Spring. Detailed Implementation
[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0035] Reference Figures 1-4 This utility model provides an embodiment of a high-temperature resistant capacitive liquid level sensor protection structure, including a sensor body 1, an mounting plate 2 fixedly connected to the lower surface of the sensor body 1, and a probe 3 fixedly connected to the bottom of the mounting plate 2. The probe 3 is the core component for liquid level detection, directly contacting the liquid being measured. By forming a capacitive detection structure with the container wall or other electrodes, it converts liquid level changes into electrical signals to achieve accurate liquid level measurement. A protective component is provided on the side wall of the probe 3 to provide all-round protection for the probe 3, enabling it to work stably in harsh environments such as high temperature and corrosion, effectively improving the service life and detection accuracy of the sensor. A fixing component is provided inside the mounting plate 2 to achieve quick installation and secure fixation between the protective component and the mounting plate 2, facilitating the disassembly and maintenance of the protective component.
[0036] The protective assembly includes a protective cover 4, whose sidewalls are slidably connected to the sidewalls of the probe rod 3. The protective cover 4 provides a physical protective barrier for the probe rod 3, blocking damage from external high temperatures, corrosive media, and mechanical impacts, effectively extending the service life of the probe rod 3. A connecting plate 9 is fixedly connected to the sidewalls of the protective cover 4, which cooperates with the mounting plate 2 to achieve the installation and fixation of the protective cover 4 through a fixing assembly. A heat sink 5 is fixedly connected to the sidewalls of the protective cover 4, which increases the contact area between the protective cover 4 and the external environment, utilizing heat conduction and heat dissipation. Based on the principle of flow, the heat absorbed by the surface of the protective cover 4 is quickly dissipated into the surrounding air, thereby reducing the temperature of the protective cover 4 and the probe 3. A supporting conductive layer 6 is installed inside the protective cover 4, with its sidewalls attached to the sidewalls of the probe 3. The supporting conductive layer 6 is made of rhenium alloy, a metallic material with a high melting point, good electrical and thermal conductivity. Its function is to maintain stable physical and chemical properties at high temperatures, effectively conducting current and heat. The supporting conductive layer 6 serves as the electrode conductor for capacitance detection, participating in the formation of the capacitive liquid level sensor. The sensor's capacitive detection structure accurately converts liquid level changes into electrical signals. Simultaneously, it helps to quickly conduct heat generated inside the probe 3, preventing localized overheating and ensuring stable operation of the probe 3 in high-temperature environments. This improves the accuracy and sensitivity of liquid level detection. A heat insulation layer 7 is provided on the sidewall of the supporting conductive layer 6. The heat insulation layer 7 is made of alumina, a common high-temperature resistant, low-thermal-conductivity inorganic non-metallic material. The heat insulation layer 7 serves as a thermal barrier within the protective cover 4, significantly reducing the transfer of external high temperatures to the probe 3 and minimizing the thermal impact on the probe 3. This protects the internal circuit components of the probe 3 from high-temperature damage. An outer layer 8 is provided on the sidewall of the heat insulation layer 7. The outer layer 8 is made of molybdenum disilicide, a material with excellent high-temperature oxidation resistance and corrosion resistance. The outer layer 8 resists acid erosion and high-temperature oxidation, forming a robust protective shell in highly corrosive and high-temperature environments such as chemical reactions. This extends the overall lifespan of the protective structure, protecting the internal supporting conductive layer 6 and the heat insulation layer 7, ensuring the long-term stable operation of the protective components.
[0037] The supporting conductive layer 6, the heat insulation layer 7, and the outer layer 8 work together to form a multi-layer protective structure. The supporting conductive layer 6 is responsible for signal transmission and heat dissipation, the heat insulation layer 7 blocks the ingress of external heat, and the outer layer 8 resists external corrosion and high-temperature oxidation. The combination of the three achieves the effect of providing all-round and multi-layer protection for the probe 3, which not only ensures the accuracy of liquid level detection, but also significantly improves the sensor's adaptability and reliability in harsh environments.
[0038] Reference Figure 2 , Figure 5 and Figure 6The fixing assembly includes a mounting shell 10, whose sidewalls are slidably connected to the mounting plate 2 and the connecting plate 9. A tapered head 14 is fixedly connected to the sidewalls of the mounting shell 10. The tapered head 14 is used to achieve quick and accurate positioning when the mounting shell 10 is inserted into the mounting plate 2 and the connecting plate 9, reducing alignment time during installation. A pull ring 11 is fixedly connected to the sidewalls of the mounting shell 10, facilitating force application by the operator. A locking block 12 is threadedly connected to the sidewalls of the mounting shell 10, the locking block 12 acting as a locking mechanism. The connection achieves a secure fastening. The sidewall of the locking block 12 is attached to the upper surface of the mounting plate 2. After the mounting shell 10 is initially fixed, the locking block 12 is used to tighten its sidewall against the upper surface of the mounting plate 2 through threaded rotation, thus providing a secondary locking and reinforcement of the mounting shell 10 and enhancing the stability of the protective cover 4. A pressing rod 13 is slidably connected inside the mounting shell 10. Through its sliding within the mounting shell 10, it serves a transmission and control function, enabling the locking and unlocking of the protective cover 4. The lower surface of the pressing rod 13 is fixedly connected to... A fixing rod 17 has a spring 18 fitted on its side wall. One end of the spring 18 is fixedly connected to the inside of the conical head 14, and the other end is fixedly connected to the lower surface of the pressing rod 13. The spring 18 is used to compress and store elastic potential energy when the pressing rod 13 is pressed down, and to release the elastic potential energy to push the pressing rod 13 back to its original position when the pressing rod 13 is released, ensuring that the fixing assembly can achieve repeated locking and unlocking operations. A fixing block 15 is fixedly connected to the side wall of the pressing rod 13, and the side wall of the fixing block 15 is slidably connected inside the mounting shell 10, so that the fixing... The fixed block 15 can slide stably within the mounting shell 10. A support rod 16 is rotatably connected to the side wall of the fixed block 15. The support rod 16 is used to rotate under the drive of the fixed block 15. When the pressing rod 13 is pressed down, the support rod 16 retracts, making it easier for the mounting shell 10 to insert into the mounting plate 2 and the connecting plate 9. When the pressing rod 13 is released, the support rod 16 expands outward and fits tightly against the lower surface of the connecting plate 9, firmly locking the protective cover 4 onto the mounting plate 2, thus directly fixing the protective cover 4 and ensuring the stability of the protective cover 4 after installation.
[0039] Working Principle: During operation, the supporting conductive layer 6, made of rhenium alloy, fits tightly against the side wall of the probe 3. On one hand, it serves as the electrode conductor for capacitance detection, forming a capacitance detection structure with the container wall or other electrodes. When the liquid level changes, the difference in dielectric constant between the liquid and air causes a change in capacitance. The supporting conductive layer 6 converts this change into an electrical signal, achieving liquid level detection. On the other hand, the excellent thermal conductivity of rhenium alloy quickly dissipates the heat generated by the probe 3 during detection or external heat conduction, preventing local overheating from affecting the electrode material performance and ensuring detection accuracy and sensitivity. The heat insulation layer 7, made of alumina, forms a thermal barrier within the protective cover 4 due to its low thermal conductivity, significantly reducing the transfer of external high temperatures to the probe 3 and protecting the internal circuit components from high temperatures. The outer layer 8, made of molybdenum disilicide, effectively resists acid erosion and high-temperature oxidation, forming a robust protective shell in highly corrosive and high-temperature environments such as chemical reactions, extending the overall lifespan of the protective structure. The heat sink 5 is fixed to the side wall of the protective cover 4, increasing the heat exchange with the external environment. The protective cover 4 increases the contact area with the surrounding environment. Utilizing the principles of heat conduction and convection, the heat absorbed by the protective cover 4 is quickly dissipated to the surrounding environment, further maintaining the temperature balance around the probe 3 and ensuring that the sensor operates under stable temperature conditions. When installing the protective cover 4, the mounting shell 10 is inserted into the mounting plate 2 and connecting plate 9 through the pull ring 11 to complete the initial fixation. Then, the pressing rod 13 is pressed, and the fixing rod 17 on the lower surface of the pressing rod 13 compresses the spring 18, simultaneously causing the fixing block 15 to slide within the mounting shell 10, causing the side wall of the fixing block 15 to rotate. The connecting support rod 16 retracts. After the mounting shell 10 is in place, the pressing rod 13 is released, the spring 18 rebounds, pushing the pressing rod 13 back to its original position. The support rod 16 is then pushed outward. Subsequently, the locking block 12 is rotated by the thread to make its side wall tightly fit against the upper surface of the mounting plate 2. At the same time, the support rod 16 is tightly fitted against the lower surface of the connecting plate 9, firmly locking the protective cover 4 onto the mounting plate 2 and locking the mounting shell 10. This enhances the stability of the protective cover 4 installation, effectively resists vibration, impact and other factors in high-temperature environments, and prevents the protective cover 4 from loosening and falling off.
[0040] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A high temperature resistant capacitive liquid level sensor protection structure comprising a sensor body (1), characterized in that: A mounting plate (2) is fixedly connected to the lower surface of the sensor body (1), a probe (3) is fixedly connected to the bottom of the mounting plate (2), a protective component is provided on the side wall of the probe (3), and a fixing component is provided inside the mounting plate (2); The protective assembly includes a protective cover (4), the side wall of the protective cover (4) is slidably connected to the side wall of the probe (3), a connecting plate (9) is fixedly connected to the side wall of the protective cover (4), a heat sink (5) is fixedly connected to the side wall of the protective cover (4), a supporting conductive layer (6) is provided inside the protective cover (4), the side wall of the supporting conductive layer (6) is attached to the side wall of the probe (3), a heat insulation layer (7) is provided on the side wall of the supporting conductive layer (6), and an outer layer (8) is provided on the side wall of the heat insulation layer (7).
2. The high temperature resistant capacitive liquid level sensor protection structure according to claim 1, characterized in that: The fixing component includes a mounting shell (10), the side wall of which is slidably connected to the mounting plate (2) and the connecting plate (9), and a conical head (14) is fixedly connected to the side wall of the mounting shell (10).
3. The high-temperature resistant capacitive liquid level sensor protection structure according to claim 1, characterized in that: The supporting conductive layer (6) is made of rhenium alloy and is used as an electrode conductor for capacitance detection. It also helps to quickly conduct the heat generated inside the probe (3) to avoid local overheating. The heat insulation layer (7) is made of alumina and is used to insulate the heat, reduce the heat transfer to the probe (3) and reduce the thermal impact. The outer layer (8) is made of molybdenum disilicide and is used to resist acid erosion and corrosion.
4. The high temperature resistant capacitive liquid level sensor protection structure according to claim 2, wherein: A pull ring (11) is fixedly connected to the side wall of the mounting shell (10), and a locking block (12) is threadedly connected to the side wall of the mounting shell (10). The side wall of the locking block (12) is attached to the upper surface of the mounting plate (2).
5. The high temperature resistant capacitive liquid level sensor protection structure according to claim 2, wherein: A pressing rod (13) is slidably connected inside the mounting shell (10), and a fixing rod (17) is fixedly connected to the lower surface of the pressing rod (13).
6. The high temperature resistant capacitive liquid level sensor protection structure according to claim 5, wherein: A spring (18) is sleeved on the side wall of the fixing rod (17). One end of the spring (18) is fixedly connected to the inside of the conical head (14), and the other end of the spring (18) is fixedly connected to the lower surface of the pressing rod (13).
7. The high temperature resistant capacitive liquid level sensor protection structure according to claim 5, wherein: The pressing rod (13) has a fixed block (15) fixedly connected to its side wall, and the side wall of the fixed block (15) is slidably connected inside the mounting shell (10).
8. The high temperature resistant capacitive liquid level sensor protection structure according to claim 7, wherein: The side wall of the fixed block (15) is rotatably connected to a support rod (16), and the side wall of the support rod (16) is attached to the lower surface of the connecting plate (9).