A structural component and a liquid level detector

Abstract

This application provides a structural component and a liquid level detector, belonging to the field of sensor welding technology. The structural component includes a structural component body with a through hole longitudinally formed at its center. A longitudinal groove, equal in length to the structural component body, is formed on the outer surface of the structural component body. An annular groove is formed on the outer surface of the structural component body, and the longitudinal groove divides the annular groove into annular groove units. The liquid level detector includes the structural component, an electric heater, a temperature sensing element, and an outer sleeve. By setting the structural component, not only can it be welded and fixed to the electric heater, but its longitudinal groove and annular groove can also achieve precise positioning of the temperature sensing element on the structural component and make the filling of welding material more uniform. This allows for omnidirectional welding of the structural component to the electric heater, temperature sensing element, and outer sleeve, improving overall consistency and uniformity, enhancing heat transfer efficiency, and shortening the response time of liquid level measurement.

Description

Technical Field

[0001] This application belongs to the field of sensor welding technology, specifically relating to a structural component and a liquid level detector. Background Technology

[0002] Currently, core liquid level monitoring in domestic third-generation nuclear power units primarily relies on liquid level detectors based on the principle of thermal diffusion. These detectors are inserted into the pressure vessel from the top of the reactor and measure the coolant level using components such as electric heaters and thermocouples. Their working principle utilizes the difference in heat transfer capacity between the liquid and vapor phases of the coolant. When the liquid level drops, the temperature of the heated thermocouples in the vapor phase rises significantly due to the change in their heat transfer coefficient; the liquid level position is determined by the temperature difference. Key performance indicators for liquid level detectors include measurement accuracy and response time, with response time being a crucial indicator of detector performance. User specifications typically require a response time ≤30 seconds. Currently, publicly available technologies mainly focus on the overall structure of the detector assembly, lacking structural designs specifically for shortening the liquid level response time. This results in detectors being unable to respond quickly to liquid level changes, failing to meet higher response time requirements, and consequently affecting the stability and reliability of reactor operation. Summary of the Invention

[0003] Therefore, the purpose of this application is to provide a structural component and a liquid level detector, which at least solves one technical problem existing in the background art.

[0004] To address the aforementioned issues, the first aspect of this application provides a structural component, including a structural component body. The structural component body has a through hole along a longitudinal direction at its center, and a longitudinal groove is formed on the outer surface of the structural component body, the longitudinal groove being of the same length as the structural component body. An annular groove is formed on the outer surface of the structural component body, and the longitudinal groove divides the annular groove into annular groove units.

[0005] Optionally, at least two of the longitudinal grooves are airflow channels, and the remaining longitudinal grooves and the annular groove are used to fill welding material.

[0006] Optionally, the longitudinal grooves are arranged at equal intervals along the circumference on the outer surface of the structural component body, and the annular grooves are arranged at equal intervals along the longitudinal direction on the outer surface of the structural component body.

[0007] Optionally, the structural component includes a first sub-structural component and a second sub-structural component, wherein the length of the first sub-structural component is four times the length of the second sub-structural component.

[0008] Optionally, the airflow channels on the first substructure and the airflow channels on the second substructure are located on the same straight line.

[0009] A second aspect of this application provides a liquid level detector, including the structural components described in any one of the above, and further including an electric heater and a temperature measuring element;

[0010] The structural component includes a first sub-structural component and a second sub-structural component, which are alternately mounted on the electric heater. The longitudinal grooves of the first sub-structural component and the second sub-structural component correspond to each other and are located on the same straight line. The temperature measuring element is correspondingly provided on the first sub-structural component and the second sub-structural component.

[0011] Optionally, the liquid level detector further includes an outer sleeve, and the first sub-structure, the second sub-structure, the electric heater, and the temperature measuring element are all installed inside the outer sleeve.

[0012] Optionally, when multiple temperature measuring elements are respectively installed on the longitudinal grooves of the first substructure and the second substructure, the longitudinal grooves corresponding to the measuring ends of the multiple temperature measuring elements are located on the same straight line.

[0013] Optionally, the first substructure is located on the heating section of the electric heater, and the second substructure is located on the non-heating section of the electric heater.

[0014] Optionally, the sum of the lengths of the plurality of first substructure members is equal to the length of the heating section of the electric heater.

[0015] By employing the above technical solution, the present invention has at least the following beneficial effects:

[0016] This application provides a structural component and a liquid level detector. The structural component integrates an electric heater and a temperature measuring element into a whole through a central through hole and a longitudinal groove on its outer surface, forming an efficient heat conduction path. This allows heat to be transferred quickly throughout the structure, reducing the heat transfer path and time, thereby significantly improving the response speed of the liquid level detector. At the same time, the electric heater and the temperature measuring element are precisely positioned, enabling the temperature measuring element to quickly sense temperature changes, thereby further improving the response time of the liquid level detector. Attached Figure Description

[0017] Figure 1 This is a cross-sectional schematic diagram of a structural component according to an embodiment of this application;

[0018] Figure 2 This is a schematic diagram of the first sub-structure component in an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of the second sub-structure component in an embodiment of this application;

[0020] Figure 4This is a schematic diagram of the assembly of the first sub-structure, the second sub-structure, and the temperature measuring component according to an embodiment of this application.

[0021] Figure 5 This is a schematic diagram of a liquid level detector according to an embodiment of this application.

[0022] The reference numerals in the attached figures are as follows:

[0023] 101. Through hole; 102. Longitudinal groove; 103. Annular groove;

[0024] 2. First sub-structural component;

[0025] 3. Second sub-structural component;

[0026] 4. Electric heater;

[0027] 501. First temperature measuring element; 502. Second temperature measuring element; 503. Third temperature measuring element; 504. Fourth temperature measuring element;

[0028] 6. Temperature measuring end installation position. Detailed Implementation

[0029] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0031] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0033] The structural component integrates the electric heater 4 and the temperature measuring element into a whole through the central through hole 101 and the longitudinal groove 102 on the outer surface, forming an efficient heat conduction path. This allows heat to be transferred quickly throughout the structure, reducing the heat transfer path and time, thereby significantly improving the response speed of the liquid level detector. At the same time, the electric heater 4 and the temperature measuring element are precisely positioned, enabling the temperature measuring element to quickly sense temperature changes, thereby further improving the response time of the liquid level detector.

[0034] See also Figure 1 As shown, a first aspect of the embodiments of this application provides a structural component, including a structural component body, a through hole 101 formed at the center of the structural component body along the longitudinal direction, a longitudinal groove 102 formed on the outer surface of the structural component body, the longitudinal groove 102 being the same length as the structural component body; and an annular groove 103 formed on the outer surface of the structural component body, the longitudinal groove 102 dividing the annular groove 103 into annular groove units.

[0035] The structural component body has a through hole 101 along the longitudinal direction at its center. That is, the axis of the through hole 101 coincides with the axis of the structural component body. At the same time, the through hole 101 passes through both ends of the structural component body. The through hole 101 is provided on the structural component body to install the electric heater 4.

[0036] Specifically, the cross-sectional shape of the through hole 101 is the same as that of the electric heater 4, so as to facilitate the installation and fixation of the structural components on the electric heater 4; at the same time, the size of the through hole 101 is the same as that of the electric heater 4, so that the two maintain a tight fit and improve the heat conduction performance.

[0037] The outer surface of the structural component body is provided with a longitudinal groove 102, which is the same length as the structural component body. By providing a longitudinal groove 102 extending toward the center of the structural component body on the outer surface of the structural component body, the structural component body forms a tooth-like structure. Part of the longitudinal groove 102 is used to install a temperature measuring element, and the other part is used as an airflow channel.

[0038] Specifically, the width and depth of the longitudinal groove 102 match the outer diameter of the temperature measuring element, which facilitates the positioning and mounting of the temperature measuring element.

[0039] Among them, an annular groove 103 is formed on the outer surface of the structural component body, and the longitudinal groove 102 divides the annular groove 103 into annular groove units; that is, the annular groove 103 and the longitudinal groove 102 are perpendicular to each other, so that the longitudinal groove 102 divides the annular groove 103 into annular groove units.

[0040] The annular groove 103 is used to cooperate with the longitudinal groove 102 to determine the installation position 6 of the measuring end of the temperature measuring element; at the same time, it is used to fill the welding material, increase the welding area between the temperature measuring element and the outer sleeve, and ensure the overall welding stability.

[0041] Specifically, the structural component body is made of high-purity nickel, which has good high and low temperature mechanical properties, mechanical properties, corrosion resistance and high thermal conductivity, and can effectively conduct heat.

[0042] In another embodiment, at least two longitudinal grooves 102 are airflow channels, and the remaining longitudinal grooves 102 and the annular groove 103 are used to fill welding material.

[0043] Among them, at least two longitudinal slots 102 are airflow channels used to connect the internal gas space of the liquid level detector, thereby realizing the gas protection function of the internal temperature measuring element.

[0044] Specifically, in this embodiment, there are two airflow channels. In other embodiments, the channels can be adjusted according to the specific operating conditions.

[0045] The remaining longitudinal grooves 102 and annular grooves 103 are used to fill welding material, increase the welding area, and improve the overall stability of the installation.

[0046] Specifically, welding materials include welding wire or welding paste.

[0047] In another embodiment, longitudinal grooves 102 are arranged at equal intervals along the circumference on the outer surface of the structural component, and annular grooves 103 are arranged at equal intervals along the longitudinal direction on the outer surface of the structural component. The equally spaced longitudinal grooves 102 and annular grooves 103 provide precise reference points for the positioning of the temperature measuring element. The measuring end of the temperature measuring element can be accurately positioned at the intersection of the longitudinal grooves 102 and the annular groove in the middle position, i.e., the temperature measuring end mounting position 6, ensuring that the temperature measuring element can directly sense the temperature changes of the heated and unheated sections, thereby improving the response speed of the temperature measuring element.

[0048] In another embodiment, such as Figure 2 and Figure 3 As shown, the structural component includes a first sub-structural component 2 and a second sub-structural component 3. The length of the first sub-structural component 2 is four times the length of the second sub-structural component 3.

[0049] The first sub-structure 2 has three annular grooves 103, which divide it into four units, one of which has the same length as the second sub-structure 3. The annular groove 103 in the middle of the first sub-structure 2 engages with the longitudinal groove 102 to define the mounting position 6 of the temperature measuring element on the first sub-structure 2. The second sub-structure 3 has one annular groove 103, which engages with the longitudinal groove 102 to define the mounting position 6 of the temperature measuring element on the second sub-structure 3.

[0050] In another embodiment, the airflow channels on the first substructure 2 and the second substructure 3 are located on the same straight line. Maintaining continuity of the airflow channels in a straight line for communication within the internal gas space helps to achieve gas protection for the internal temperature sensing element.

[0051] like Figure 4 and Figure 5 As shown, the second aspect of this application provides a liquid level detector, which includes the structural components of any one of the above, and also includes an electric heater 4 and a temperature measuring element;

[0052] The structural components include a first sub-structural component 2 and a second sub-structural component 3, which are alternately mounted on the electric heater 4. The longitudinal groove 102 of the first sub-structural component 2 and the longitudinal groove 102 of the second sub-structural component 3 correspond to each other and are located on the same straight line. Temperature measuring elements are correspondingly provided on the first sub-structural component 2 and the second sub-structural component 3.

[0053] The structural component not only meets the requirements for welding and fixing with the electric heater 4, but its longitudinal groove 102 and annular groove 103 can realize the arrangement and fixing of the temperature measuring element in the structural component and the welding and fixing with the outer tube, so that the welding material is filled more evenly. It can meet the requirements for all-round welding of the structural component with the electric heater 4, the temperature measuring element and the outer tube, improve the overall consistency and uniformity of the structural component, improve the heat transfer efficiency, and shorten the response time of liquid level measurement.

[0054] The liquid level detector operates on the principle of measuring the reactor core liquid level by measuring the temperature difference between two temperature sensors. One temperature sensor is located in the heating section of electric heater 4, and the other is located in the non-heating section. Based on the physical properties of water, water vapor, and air, there is a significant difference between the heat transfer coefficients of water and water vapor. When electric heater 4 is in heating mode, the measured temperature is lower when the temperature sensor in the heating section is submerged in water, and higher when it is submerged in water vapor. A temperature threshold is defined as the temperature difference when the temperature sensor in the heating section of electric heater 4 is submerged in water vapor. The shorter the time to reach this temperature threshold, the faster the response of the temperature sensor and the shorter the liquid level response time.

[0055] A through hole 101 is made in the center of the structural component to install the electric heater 4 and weld it into one piece. A temperature measuring element is installed through at least part of the longitudinal groove 102 on the structural component and welded into one piece. Then it is installed into the outer tube and welded to the outer tube for fixation. This not only meets the needs of internal integration and fixation of the components, but also improves the overall heat transfer efficiency of the structure after welding and shortens the response time of liquid level measurement (meeting the key indicator of ≤30s).

[0056] In this embodiment, the first sub-structure 2 and the second sub-structure 3 are alternately fitted onto the electric heater 4. That is, the electric heater 4 is installed on the through hole 101 of the first sub-structure 2 and the second sub-structure 3. In this embodiment, the through hole 101 is a hole with a circular cross-section, which matches the cylindrical electric heater 4, so that the electric heater 4 can pass through the first sub-structure 2 and the second sub-structure 3 and be welded and fixed to the first sub-structure 2 and the second sub-structure 3.

[0057] Specifically, in this embodiment, the first sub-structure 2 is a heated structure, and the second sub-structure 3 is a non-heated structure; there are two of each of the first and second sub-structures; the first sub-structures 2 are designated as No. 1 and No. 2; the second sub-structures 3 are designated as No. 1 and No. 2. Figure 5 As shown, from left to right, they are No. 1 second sub-structure component, No. 1 first sub-structure component, No. 2 second sub-structure component, and No. 2 first sub-structure component.

[0058] The temperature measuring element includes a first temperature measuring element 501, a second temperature measuring element 502, a third temperature measuring element 503, and a fourth temperature measuring element 504. The number of temperature measuring elements is the same as the number of structural elements.

[0059] When multiple temperature measuring elements are installed on the longitudinal grooves 102 of the first substructure 2 and the second substructure 3 respectively, the longitudinal grooves 102 corresponding to the measuring ends of the multiple temperature measuring elements are located on the same straight line.

[0060] Specifically: In this embodiment, there are six longitudinal grooves 102. For ease of description, the six longitudinal grooves 102 are respectively defined as longitudinal groove No. 1, longitudinal groove No. 2, longitudinal groove No. 3, longitudinal groove No. 4, longitudinal groove No. 5, and longitudinal groove No. 6.

[0061] During installation, the first temperature measuring element 501 is installed on the first longitudinal groove of the second first substructure component, with its measuring end located at the temperature measuring end mounting position 6 at the intersection of the first longitudinal groove of the second first substructure component and the annular groove 103 located in the middle position; the second temperature measuring element 502 is at least partially installed on the second longitudinal groove of the second first substructure component, with its measuring end installed on the first longitudinal groove of the second second substructure component, and its measuring end located at the temperature measuring end mounting position 6 at the intersection of the first longitudinal groove of the second second substructure component and the annular groove 103; the third temperature measuring element 503 is at least partially installed on the second first substructure component. The measuring end of the third temperature measuring element 503 is installed on the third longitudinal groove of the first sub-structure and the third longitudinal groove of the second sub-structure. The measuring end is located at the temperature measuring end mounting position 6 at the intersection of the first longitudinal groove of the first sub-structure and the annular groove 103 located in the middle position. The fourth temperature measuring element 504 is at least partially installed on the fourth longitudinal groove of the second sub-structure, the fourth longitudinal groove of the second sub-structure, and the fourth longitudinal groove of the first sub-structure. The measuring end is located at the temperature measuring end mounting position 6 at the intersection of the first longitudinal groove of the second sub-structure and the annular groove 103. Through the above installation method, the measuring ends of the first temperature measuring element 501, the second temperature measuring element 502, the third temperature measuring element 503, and the fourth temperature measuring element 504 are all located on the first longitudinal groove of the structure. Welding material is filled in the longitudinal groove 102 where the temperature measuring elements are installed, and the temperature measuring elements are welded and fixed to the structure. In addition, in other embodiments, the correspondence between the temperature measuring element and the longitudinal groove 102 can be adjusted according to the specific circumstances to facilitate the installation of the temperature measuring element.

[0062] After the temperature measuring component is installed, the fifth and sixth longitudinal slots on the first sub-structure 2 and the second sub-structure 3 serve as gas channels. These channels are used to connect the gas space within the component. In terms of spatial arrangement, the longitudinal slots 102 corresponding to each structure are kept in the same straight line, and the airflow channels on different structures can be connected left and right, which facilitates airflow protection inside the structure.

[0063] Specifically, in this embodiment, the temperature measuring element is an armored thermocouple; in other embodiments, the type of temperature measuring element can be adjusted according to the specific operating conditions.

[0064] In this embodiment, the electric heater 4 is an armored cable type electric heater; in other embodiments, the type of temperature measuring element can be adjusted according to the specific working conditions.

[0065] In another embodiment, the level detector further includes an outer sleeve, within which the first sub-structure 2, the second sub-structure 3, the electric heater 4, and the temperature sensor are integrally mounted. The outer sleeve provides mechanical protection for the internal electric heater 4, temperature sensor, and structural components, preventing external mechanical damage during use. Simultaneously, the outer sleeve isolates the internal components from the external environment, preventing coolant or other media from directly contacting the electric heater 4 and temperature sensor, thus helping to extend the component's service life.

[0066] The outer diameters of the first sub-structural component 2 and the second sub-structural component 3 match the inner diameter of the outer sleeve. This facilitates the overall installation of the first sub-structural component 2, the second sub-structural component 3, the electric heater 4, and the temperature measuring element onto the outer sleeve.

[0067] In another embodiment, the first substructure 2 is located on the heating section of the electric heater 4, and the second substructure 3 is located on the non-heating section of the electric heater 4.

[0068] The first substructure 2 is located on the heating section of the electric heater 4. That is, the first substructure 2 covers the heating section of the electric heater 4, i.e. the part with the heating wire. It uses high thermal conductivity nickel material to quickly and evenly transfer heat, so that the temperature measuring elements (first temperature measuring element 501 and third temperature measuring element 503) arranged on the first substructure 2 can directly sense the temperature change of the heating area, forming an efficient conduction path. When the liquid level drops, the location of the temperature measuring element at the heating section of the electric heater 4 is exposed to steam, and the first substructure 2 heats up rapidly. The temperature measuring element senses the temperature jump instantaneously through direct contact with the longitudinal groove 102 of the first substructure 2.

[0069] The second sub-structure 3 is located on the unheated section of the electric heater 4. In other words, the second sub-structure 3 covers the unheated section of the electric heater 4, i.e., the part without heating wires. Although its material is thermally conductive, it has no active heat source. Therefore, the second sub-structure 3 only transmits ambient temperature, ensuring that the temperature sensors (second temperature sensor 502 and fourth temperature sensor 504) arranged on it only reflect the true ambient temperature and are not affected by heat diffusion from the heating section. Because it has no heat source and is directly thermally coupled to the environment, the temperature sensors always rapidly track the coolant temperature, providing a stable benchmark for temperature difference calculations.

[0070] The structural components adopt an integrated design. The length of the heating section of the first sub-structural component 2 is matched with that of the electric heater 4, which can make the structural components heat up evenly and completely, thereby enabling the temperature measuring element arranged in the longitudinal groove 102 to quickly sense the temperature and ensure the thermal response sensitivity of the temperature measuring element.

[0071] In another embodiment, the sum of the lengths of the plurality of first substructure members 2 is equal to the length of the heating section of the electric heater 4.

[0072] The first substructure 2 is made of high-purity nickel with high thermal conductivity. When the first substructure 2 completely covers the heating section of the electric heater 4, the heat generated by the electric heater 4 can be evenly and efficiently conducted to the entire contact area through the first substructure 2, avoiding local hot spots or cold spots caused by insufficient coverage, and ensuring a highly uniform temperature distribution throughout the heating section.

[0073] When the first substructure 2 completely covers the heating section, the temperature measuring element directly and fully contacts the heat source area through the first substructure 2. The uniform heating of the first substructure 2 enables the temperature measuring element to instantly sense temperature changes, significantly shortening the time it takes to reach the set temperature difference threshold, thereby directly shortening the response time of liquid level measurement (meeting the key indicator of ≤30s).

[0074] The manufacturing process of the liquid level detector is as follows:

[0075] Taking a typical liquid level measuring point as an example, there are four structural components in total, including two first sub-structural components 2 and two second sub-structural components 3; one electric heater 4; four temperature measuring components; and one outer tube.

[0076] An electric heater 4 coated with welding material is passed through the first sub-structure 2 and the second sub-structure 3, with the first sub-structure 2 and the second sub-structure 3 arranged alternately to ensure that the first sub-structure 2 is located in the heating section of the electric heater 4 and completely covers the heating section, while the second sub-structure 3 is located in the non-heating section of the electric heater 4; the positions of the two first sub-structure 2 and the two second sub-structure 3 are adjusted to ensure that the longitudinal grooves 102 on the first sub-structure 2 and the second sub-structure 3 are on the same straight line; the electric heater 4 is welded into the through hole 101 of the first sub-structure 2 and the second sub-structure 3 to form a whole;

[0077] Four temperature measuring elements are installed sequentially in the longitudinal groove 102, ensuring that the measuring ends of the temperature measuring elements are located in the longitudinal groove 102 in a straight line; welding material is filled into the longitudinal groove 102 where the temperature measuring elements are installed, and the temperature measuring elements are welded to the structural parts as one piece;

[0078] The required welding material is filled into each longitudinal groove 102 and annular groove 103, except for the temperature measuring element and the airflow channel. The structural component, together with the welded and fixed electric heater 4 and temperature measuring element, is inserted into the outer tube. The welding between each component and the outer tube is completed in the outer tube.

[0079] The structure of the through hole 101 in the center of the structural component, as well as the longitudinal groove 102 and the annular groove 103 on the outer surface, is suitable for the uniform filling of welding materials, so as to realize the all-round welding of the structural component with the electric heater 4, the temperature measuring component and the outer sleeve, as well as the uniformity and integrity of the welding, making the entire welded structure continuous and firm, ensuring the uniform distribution of each material, and improving the heat transfer efficiency.

[0080] By setting up structural components, not only can the welding and fixing with the electric heater 4 be satisfied, but the longitudinal groove 102 and the annular groove 103 can achieve precise positioning of the temperature measuring element on the structural components and make the filling of welding material more uniform. This satisfies the all-round welding of the structural components with the electric heater 4, the temperature measuring element and the outer sleeve, improves the overall consistency and uniformity, improves the heat transfer efficiency and shortens the response time of liquid level measurement.

[0081] It will be readily understood by those skilled in the art that the aforementioned advantageous methods can be freely combined and superimposed without conflict.

[0082] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A liquid level detector, characterized in that, The system includes a structural component, which includes a structural component body. The structural component body has a through hole (101) at its center along the longitudinal direction. The outer surface of the structural component body has a longitudinal groove (102) of the same length as the structural component body. The outer surface of the structural component body has an annular groove (103) of the longitudinal groove (102) dividing the annular groove (103) into annular groove units. The liquid level detector also includes an electric heater (4) and a temperature measuring element; The structural components include a first sub-structural component (2) and a second sub-structural component (3). The first sub-structural component (2) and the second sub-structural component (3) are alternately mounted on the electric heater (4). The longitudinal groove (102) of the first sub-structural component (2) and the longitudinal groove (102) of the second sub-structural component (3) correspond to each other and are located on the same straight line. The temperature measuring element is correspondingly provided on the first sub-structural component (2) and the second sub-structural component (3).

2. The liquid level detector according to claim 1, characterized in that, At least two of the longitudinal grooves (102) are airflow channels, and the remaining longitudinal grooves (102) and the annular groove (103) are used to fill welding material.

3. The liquid level detector according to claim 2, characterized in that, The longitudinal grooves (102) are arranged at equal intervals along the circumference on the outer surface of the structural component body, and the annular grooves (103) are arranged at equal intervals along the longitudinal direction on the outer surface of the structural component body.

4. The liquid level detector according to any one of claims 2 to 3, characterized in that, The length of the first substructure (2) is four times the length of the second substructure (3).

5. The liquid level detector according to claim 4, characterized in that, The airflow channel on the first substructure (2) and the airflow channel on the second substructure (3) are located on the same straight line.

6. The liquid level detector according to claim 1, characterized in that, The liquid level detector also includes an outer tube, and the first sub-structure (2), the second sub-structure (3), the electric heater (4) and the temperature measuring element are installed inside the outer tube.

7. The liquid level detector according to claim 1, characterized in that, When multiple temperature measuring elements are respectively installed on the longitudinal grooves (102) of the first substructure (2) and the second substructure (3), the longitudinal grooves (102) corresponding to the measuring ends of the multiple temperature measuring elements are located on the same straight line.

8. The liquid level detector according to claim 1, characterized in that, The first substructure (2) is located on the heating section of the electric heater (4), and the second substructure (3) is located on the non-heating section of the electric heater (4).

9. The liquid level detector according to claim 1, characterized in that, The sum of the lengths of the plurality of first substructures (2) is equal to the length of the heating section of the electric heater (4).

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