Insulating silica gel detection device

Abstract

The invention belongs to the technical field of material testing, and discloses an insulating silica gel detection device, which comprises a host cabinet body and a transparent cover plate arranged above the host cabinet body, the detection device further comprises a transparent sleeve, a fixed electrode, a connecting electrode, a ceramic placement box and a safety protection assembly; the transparent sleeve is arranged in the host cabinet body and is positioned below the transparent cover plate; the fixed electrode is fixedly arranged in the transparent sleeve; the connecting electrode is arranged on the fixed electrode; the ceramic placement box is arranged between the two connecting electrodes, a hole is formed in the ceramic placement box, and under the action of the safety protection assembly, original dangerous operation with high-voltage shock and electric arc damage risks is converted into a safe, stable, automatic and reliable standardized process; therefore, the personal safety and the equipment safety are greatly guaranteed, and the quality and the credibility of the detection data are fundamentally improved.

Description

Technical Field

[0001] This invention belongs to the field of materials testing technology, and in particular relates to a testing device for insulating silicone. Background Technology

[0002] Silicone insulating material, as a key polymer insulating material, is widely used in circuit board encapsulation, connector sealing, and high-voltage component insulation in electronic components, power equipment, and new energy vehicles. The reliability of its coating quality directly determines the safety and lifespan of the final product. Frequent electrical performance tests are often required during production and quality inspection. Currently, such testing devices generally use fixed electrode connections or simple plug-in interfaces. This design has a significant safety hazard: during the process of the operator connecting the test electrode to the device under test, the test circuit is often already energized. Specifically, taking a typical withstand voltage test as an example, it requires applying a momentary high voltage between the conductors on both sides of the insulating silicone being tested. When a traditional test pen or clamp approaches or even touches the test piece, the high voltage is already present, which leads to the following serious problems: If operators make operational errors or accidentally touch the electrode, it can easily cause high-voltage electric shock, which seriously threatens personal safety. When the electrodes are brought close together, arcing occurs in the air gap due to the potential difference. Especially for high-voltage testing, the arc can burn the surface of the product being tested and affect the accuracy of the test. Summary of the Invention

[0003] This invention addresses the problems in existing technologies where operator error or accidental contact can easily lead to high-voltage electric shock, seriously threatening personal safety. Furthermore, during electrode approach, potential differences can cause arcing in the air gap, particularly in high-voltage testing, resulting in burns to the surface of the tested product and affecting test accuracy. The invention proposes the following technical solution: An insulating silicone testing device includes: a main unit cabinet and a transparent cover plate installed on top of the main unit cabinet; The testing device also includes a transparent sleeve, fixed electrodes, connecting electrodes, a ceramic placement box, and safety protection components; The transparent sleeve is installed inside the main unit cabinet and is located below the transparent cover plate; The fixed electrode is fixedly disposed inside the transparent sleeve; The connecting electrode is disposed on the fixed electrode; The ceramic placement box is disposed between the two connecting electrodes, and the ceramic placement box has a hole inside, which allows the connecting electrodes to move horizontally along the hole inside the ceramic placement box. The safety protection component is installed between the main unit cabinet and the transparent sleeve to fix the power supply of the electrodes.

[0004] As a preferred embodiment of the above technical solution, the security protection component includes a linear drive structure fixedly installed inside the main unit cabinet. A connecting plate is installed at the movable end of the linear drive structure, a movable electrode is installed at the top of the connecting plate, and a sphere is sleeved on the outside of the movable electrode.

[0005] As a preferred embodiment of the above technical solution, the inner wall of the sphere is integrally formed with a guide block, and an arc-shaped groove is formed on the outer side of the movable electrode at one end of the guide block. The top and middle outer sides of the outer surface of the movable electrode are integrally formed with a limiting disk. The end face of the limiting disk near the sphere is arc-shaped. A hole is formed in the middle of the fixed electrode. The maximum diameter of the limiting disk at the bottom of the sphere is smaller than the inner diameter of the hole. A groove is provided on the bottom of the outer surface of the sphere.

[0006] As a preferred embodiment of the above technical solution, the linear drive structure is composed of a drive motor and a lead screw, wherein the lead screw and the connecting plate are connected by threads, and a guide groove is provided inside the main unit cabinet, and the connecting plate is slidably connected inside the guide groove.

[0007] As a preferred embodiment of the above technical solution, an installation plate is fixedly installed above the limiting plate at the top of the sphere, a spiral column is fixedly installed at the top of the installation plate, a rotating ring is connected to the top of the outer surface of the spiral column, a fixed plate is movably connected to the bottom of the rotating ring, and the fixed plate is fixedly installed on the transparent sleeve, a connecting arm is movably provided at the top of the rotating ring, and an L-shaped clamping arm is movably provided at one end of the connecting arm.

[0008] As a preferred embodiment of the above technical solution, the top of the mounting plate is provided with a sliding groove, and the bottom of the L-shaped clamping arm is provided with a protrusion, which is located inside the sliding groove.

[0009] As a preferred embodiment of the above technical solution, the connecting electrode has a snap-fit ​​groove inside, and the cross-section of the snap-fit ​​groove is concave.

[0010] As a preferred embodiment of the above technical solution, the upper part of the movable electrode is a spiral segment, and the lower part of the movable electrode is a smooth rod segment.

[0011] As a preferred embodiment of the above technical solution, a U-shaped groove is provided at the top of the fixed electrode, and the connecting electrode is located inside the U-shaped groove.

[0012] The beneficial effects of this invention are as follows: (1) Through the action of safety protection components, the dangerous operation that originally had the risk of high voltage electric shock and electric arc damage is transformed into a safe, stable, automatic and reliable standardized process. This not only greatly protects personal safety and equipment safety, but also fundamentally improves the quality and credibility of the test data. (2) At the same time, it can ensure the stability of the connection between the fixed electrode and the connecting electrode, thereby effectively resisting the vibration and impact during equipment operation, ensuring that the physical position of the electrical connection point remains unchanged throughout the entire test cycle, fundamentally eliminating test interruption or data jump caused by loose connection. (3) It also causes relative scraping between the contact surface with the fixed electrode, which can effectively wear away and remove the non-conductive film formed by oxidation and pollution during long-term use, and always expose a clean metal contact surface, ensuring that the connection point in the entire high-voltage circuit has extremely low and constant contact resistance. Attached Figure Description

[0013] Figure 1 The diagram shown is a structural schematic of an insulating silicone testing device according to Embodiment 1; Figure 2 The diagram shown is an internal view of an insulating silicone testing device according to Embodiment 1; Figure 3 The diagram shown is a structural schematic from another perspective of an insulating silicone testing device in Embodiment 1; Figure 4 The diagram shown is a structural schematic of the ceramic placement box in Embodiment 1; Figure 5 The diagram shown is a structural schematic of the safety protection component in Embodiment 1; Figure 6 What is shown is Figure 5 Schematic diagram of the structure of region A in the middle; Figure 7 The diagram shown is a schematic of the installation structure of the L-shaped clamping arm in Embodiment 1; Figure 8 The image shown is a physical diagram of an insulating silicone testing device according to Embodiment 1.

[0014] In the diagram: 1. Main unit cabinet; 2. Transparent cover; 3. Transparent sleeve; 4. Fixed electrode; 5. Connecting electrode; 6. Ceramic placement box; 7. Safety protection components; 71. Linear drive structure; 72. Connecting plate; 73. Movable electrode; 74. Fixed plate; 75. Guide block; 76. Sphere; 77. Mounting plate; 78. Spiral column; 79. Rotating ring; 710. Connecting arm; 711. L-shaped clamping arm; 712. Groove; 713. Limiting plate; 714. Snap-fit ​​groove. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0016] Example 1 This invention provides an insulating silicone testing device, such as... Figures 1 to 8As shown, the device includes: a main unit cabinet 1 and a transparent cover plate 2 installed on top of the main unit cabinet 1; the detection device also includes a transparent sleeve 3, a fixed electrode 4, a connecting electrode 5, a ceramic placement box 6, and a safety protection component 7; the transparent sleeve 3 is installed inside the main unit cabinet 1 and located below the transparent cover plate 2; the fixed electrode 4 is fixedly installed inside the transparent sleeve 3; the connecting electrode 5 is installed on the fixed electrode 4; the ceramic placement box 6 is located between the two connecting electrodes 5, and the ceramic placement box 6 has a hole inside for the connecting electrode 5 to move horizontally along the hole inside the ceramic placement box 6; the safety protection component 7 is installed between the main unit cabinet 1 and the transparent sleeve 3 for energizing the fixed electrode 4.

[0017] If the operator makes a mistake or accidentally touches the electrode, it can easily cause a high-voltage electric shock, which seriously threatens personal safety. When the electrodes are brought close together, an arc is generated in the air gap due to the potential difference. Especially for high-voltage testing, the arc can burn the surface of the product being tested and affect the accuracy of the test. Therefore, in this application, through the action of the safety protection component 7, the dangerous operation that originally posed a risk of high voltage electric shock and arc damage is transformed into a safe, stable, automatic and reliable standardized process. This not only greatly protects personal safety and equipment safety, but also fundamentally improves the quality and credibility of the test data. Furthermore, it can ensure the stability of the connection between the fixed electrode 4 and the connecting electrode 5, thereby effectively resisting vibration and impact during equipment operation. It ensures that the physical position of the electrical connection point remains unchanged throughout the entire test cycle, fundamentally eliminating test interruptions or data jumps caused by loose connections. It also causes relative scraping between the contact surface with the fixed electrode 4, which can effectively wear away and remove the non-conductive film formed by oxidation and contamination during long-term use, always exposing a clean metal contact surface, and ensuring that the connection point in the entire high-voltage circuit has extremely low and constant contact resistance.

[0018] In use, the insulating silicone sample to be tested is placed inside the ceramic placement box 6 (which contains water). Then, the connecting electrodes 5 are adjusted so that the insulating silicone sample inside the ceramic placement box 6 is clamped between the two connecting electrodes 5. The entire assembly is then placed on top of the fixed electrode 4 of the main unit cabinet 1, and the transparent sleeve 3 is placed on top. Next, the device is connected to the grounding wire, then connected to the power supply, and then the switch is turned on. At this time, the protective assembly 7 is connected to the fixed electrode 4, allowing electricity to be transmitted along the fixed electrode 4 to the connecting electrode 5, and then along the connecting electrode 5 to the insulating silicone sample, thereby performing a withstand voltage test on the insulating silicone sample.

[0019] Specifically, the top of the main unit cabinet 1 is symmetrically and integrally formed with a transparent sleeve 3. A fixed electrode 4 is snapped into the transparent sleeve 3. A U-shaped groove is opened at the top of the fixed electrode 4. A connecting electrode 5 is fitted inside the U-shaped groove of the fixed electrode 4. The U-shaped groove is used to limit the position of the connecting electrode 5. The two connecting electrodes 5 are fitted with the same ceramic placement box 6. Horizontal through holes are opened on both sides of the ceramic placement box 6. The two connecting electrodes 5 are inserted into the through holes from both sides and can move along the axial direction of the holes to adjust the spacing and clamp the sample placed in the box. A sealing structure is provided at the connection between the ceramic placement box 6 and the connecting electrode 5. A safety protection component 7 is fixedly installed inside the main unit cabinet 1.

[0020] To ensure that the fixed electrode 4 is connected to the power supply in the above embodiments, the following solution is provided: Figure 4 and Figure 5 As shown, the safety protection component 7 includes a linear drive structure 71 fixedly installed inside the host cabinet 1. A connecting plate 72 is installed on the movable end of the linear drive structure 71, and a movable electrode 73 is installed on the top of the connecting plate 72. A ball 76 is sleeved on the outside of the movable electrode 73.

[0021] In use, the linear drive structure 71 is connected to the power supply and drives the connecting plate 72 to descend. When the connecting plate 72 descends, it drives the movable electrode 73 to descend. When the movable electrode 73 descends, it drives the ball 76 to press and fit with the fixed electrode 4. At this time, the current inside the movable electrode 73 is transmitted to the fixed electrode 4 through the ball 76. Specifically, a linear drive structure 71 is installed inside the main unit cabinet 1 by screws. The linear drive structure 71 is composed of a drive motor and a lead screw. A connecting plate 72 is connected to the outside of the lead screw of the linear drive structure 71 by threads. A guide groove is opened inside the main unit cabinet 1. The connecting plate 72 is slidably connected inside the guide groove. A movable electrode 73 is symmetrically fixedly installed on the top of the connecting plate 72. A ball 76 is sleeved on the outside of the movable electrode 73. A positioning hole is opened in the middle of the ball 76. The ball 76 is sleeved on the outside of the movable electrode 73 through the positioning hole. Furthermore, in order to achieve the purpose of cleaning the connection between the sphere 76 and the fixed electrode 4 in the above embodiments, the following solution is provided, such as... Figure 5 and Figure 6 As shown, a guide block 75 is integrally formed on the inner wall of the sphere 76. An arc-shaped spiral groove is formed on the outer side of the movable electrode 73 at one end of the guide block 75. A limiting disk 713 is integrally formed on the top and middle outer sides of the outer surface of the movable electrode 73. The end face of the limiting disk 713 near the sphere 76 is arc-shaped. A hole is formed in the middle of the fixed electrode 4. The maximum diameter of the limiting disk 713 at the bottom of the sphere 76 is smaller than the inner diameter of the hole. A groove 712 is provided on the bottom of the outer surface of the sphere 76. The upper part of the movable electrode 73 is a spiral section, and the lower part of the movable electrode 73 is a smooth rod section.

[0022] When in use, the lower section of the movable electrode 73 passes through the hole of the fixed electrode 4 first, causing the ball 76 to move down synchronously, so that it is stably attached to the contact surface of the fixed electrode 4, and the circuit is turned on first. At this time, the upper section of the movable electrode 73 has not yet been activated. Next, the movable electrode 73 continues to descend. Since the movable electrode 73 is restricted as a whole, it cannot rotate on its own. The arc-shaped spiral groove on the upper part of the movable electrode 73 moves relative to the guide block 75 fixedly installed inside the ball 76. When the movable electrode 73 descends in a straight line, the inclined surface of the arc-shaped spiral groove interacts with the stationary guide block 75. This force can be decomposed into an axial force and a tangential component. The tangential component constitutes a forced torque that drives the ball 76 to rotate around the axis of the movable electrode 73. Driven by the torque, the ball 76 begins to rotate in the hole of the fixed electrode 4, overcoming static friction. The limiting disk 713 at the bottom of the ball 76 cooperates with the T-shaped hole structure of the fixed electrode 4, which not only ensures that the ball 76 will not fall off, but also provides the necessary space and constraint for its rotation. When the ball 76 rotates, the groove 712 designed at the bottom of its outer surface will strongly scrape the contact surface of the fixed electrode 4. Specifically, the upper part of the movable electrode 73 is a spiral section, and the lower part of the movable electrode 73 is a smooth rod section. An arc-shaped spiral groove is opened on the upper part of the movable electrode 73. A guide block 75 is slidably connected inside the arc-shaped spiral groove. The outer side of the guide block 75 is welded to the inner wall of the sphere 76. A limiting disk 713 is integrally formed on the top and middle outer sides of the outer surface of the movable electrode 73. A groove is opened on one end face of the limiting disk 713 near the sphere 76. The groove is arc-shaped. A hole is opened in the middle of the fixed electrode 4. The hole is T-shaped. The maximum diameter of the limiting disk 713 at the bottom of the sphere 76 is smaller than the minimum inner diameter of the hole. Furthermore, to achieve the rotation of sphere 76 in the above embodiments, the following solution is provided, such as... Figures 4 to 7 As shown, an installation plate 77 is fixedly installed above the limiting plate 713 at the top of the sphere 76. A spiral column 78 is fixedly installed at the top of the installation plate 77. A rotating ring 79 is connected to the top of the outer surface of the spiral column 78. A fixed plate 74 is movably connected to the bottom of the rotating ring 79, and the fixed plate 74 is fixedly installed on the transparent sleeve 3. A connecting arm 710 is movably provided at the top of the rotating ring 79. An L-shaped clamping arm 711 is movably provided at one end of the connecting arm 710. A sliding groove is provided at the top of the installation plate 77. A protrusion is provided at the bottom of the L-shaped clamping arm 711. The protrusion is located inside the sliding groove. A snap-fit ​​groove 714 is provided inside the connecting electrode 5. The cross-section of the snap-fit ​​groove 714 is concave. When in use, as the spiral column 78 descends, the spiral column 78 drives the rotating ring 79 to rotate along the top of the fixed disk 74 via the thread. When the rotating ring 79 rotates, it drives the L-shaped clamping arm 711 to move along the mounting disk 77 via the connecting arm 710 and enters the snap-fit ​​groove 714, thereby realizing the connection between the L-shaped clamping arm 711 and the connecting electrode 5. Specifically, a fixed plate 74 is fixedly installed on the top of the inner wall of the transparent sleeve 3. A mounting plate 77 (made of insulating material) is snapped onto the top of the limiting plate 713 located at the top of the sphere 76. A spiral column 78 is fixedly installed on the top of the mounting plate 77, and the spiral column 78 penetrates the fixed plate 74. A rotating ring 79 is threadedly connected to the top of the spiral column 78. A convex ring is welded to the bottom of the rotating ring 79. A limiting groove is opened inside the fixed plate 74 at the position corresponding to the outer side of the convex ring, so that the rotating ring 79 is positioned by the convex ring and the limiting groove and can rotate. A connecting arm 710 is movably connected to the top of the rotating ring 79 through a column. An L-shaped clamping arm 711 is movably connected to one end of the connecting arm 710 through a column. A sliding groove is opened on the top of the mounting plate 77. A protrusion is provided at the bottom of the L-shaped clamping arm 711. The protrusion is located inside the sliding groove. A snap-fit ​​groove 714 is opened inside the connecting electrode 5. The cross-section of the snap-fit ​​groove 714 is concave.

[0023] Working principle: The operator opens the transparent cover 2 and places the insulating silicone sample to be tested inside the ceramic placement box 6. Then, an appropriate amount of water is injected into the ceramic placement box 6. The operator then manually adjusts the two connecting electrodes 5 so that they move horizontally towards each other along the horizontal through holes on both sides of the ceramic placement box 6. Through this adjustment, the inner ends of the two connecting electrodes 5 stably hold the two ends of the insulating silicone sample, forming a preliminary test circuit preparation. Then, the "ceramic placement box 6 and connecting electrodes 5" assembly with the sample is placed into the top of the main unit cabinet 1, ensuring that the bottom of the two connecting electrodes 5 is located in the U-shaped grooves at the top of the two fixed electrodes 4. The U-shaped grooves play a radial limiting role to prevent the connecting electrodes 5 from shifting during the test. Next, reliably connect the equipment grounding wire, then connect the main power supply to the equipment, turn on the main switch of the equipment, initialize the system, and prepare for testing; Next, the drive motor of the linear drive structure 71 receives the control signal and starts to drive the lead screw to rotate. Since the connecting plate 72 is connected to the lead screw by a thread and is restricted from rotation by the guide groove in the main unit cabinet 1, the rotation of the lead screw is converted into the linear downward motion of the connecting plate 72. The connecting plate 72 drives the movable electrode 73 symmetrically installed at its top and all the associated components (including the ball 76, the mounting plate 77, the spiral column 78, etc.) to move downward synchronously. The lower section of the movable electrode 73 first passes through the T-shaped hole in the middle of the fixed electrode 4. The sphere 76, fitted onto the movable electrode 73, then descends, its outer surface forming a stable and tight physical contact with the conductive contact surface of the fixed electrode 4. At this time, current is transmitted from the inside of the energized movable electrode 73, through the sphere 76, to the fixed electrode 4, then through the connecting electrode 5, and finally applied to the insulating silicone sample. The high-voltage circuit is safely and preferentially established before mechanical locking. As the movable electrode 73 descends as a whole, the spiral column 78 fixed to it descends synchronously. The spiral column 78 engages with the rotating ring 79 via threads. Because the convex ring at the bottom of the rotating ring 79 is confined within the limiting groove of the fixed disk 74... (Axially fixed, rotatable only), the linear motion of the helical column 78 forces the rotating ring 79 to rotate around the axis. The rotation of the rotating ring 79 drives the connecting arm 710 at its top to move. The connecting arm 710 converts the rotational motion into traction on the tail of the L-shaped clamping arm 711. The protrusion at the bottom of the L-shaped clamping arm 711 is restricted by the radial groove at the top of the mounting plate 77, causing its front end (clamping end) to generate radial and centripetal linear motion. The front end of the L-shaped clamping arm 711 is finally firmly inserted into the concave snap-fit ​​groove 714 on the side of the connecting electrode 5, forming a rigid connection. This locking effectively resists the vibration and impact during equipment operation and ensures the absolute stability of the electrical connection point during testing. After the electrical connection is established, the movable electrode 73 continues its downward stroke. The inclined surface of the arc-shaped spiral groove on the upper part of the movable electrode 73 slides relative to the guide block 75 fixed inside the sphere 76. Since the movable electrode 73 is restricted by the anti-rotation structure, this interaction generates a tangential component force, which constitutes a forced torque to drive the sphere 76 to rotate. Under the drive of this torque, the sphere 76 rotates in the hole of the fixed electrode 4. During the rotation, the groove 712 at the bottom of the outer surface of the sphere 76 strongly scrapes the contact surface of the fixed electrode 4, effectively grinding and removing the oxide film and contaminants, always exposing a clean metal contact surface, and ensuring that the contact resistance is extremely low and constant.

[0024] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it.

Claims

1. An insulating silicone testing device, characterized in that, include: The main unit cabinet (1) and the transparent cover plate (2) installed on the top of the main unit cabinet (1); the detection device also includes a transparent sleeve (3), a fixed electrode (4), a connecting electrode (5), a ceramic placement box (6) and a safety protection component (7); the transparent sleeve (3) is installed inside the main unit cabinet (1) and located below the transparent cover plate (2); the fixed electrode (4) is fixed inside the transparent sleeve (3); the connecting electrode (5) is set on the fixed electrode (4); the ceramic placement box (6) is set between the two connecting electrodes (5), and the ceramic placement box (6) has a hole inside for the connecting electrode (5) to move horizontally along the hole inside the ceramic placement box (6); the safety protection component (7) is installed between the main unit cabinet (1) and the transparent sleeve (3) for energizing the fixed electrode (4).

2. The material testing technology according to claim 1, characterized in that, The safety protection component (7) includes a linear drive structure (71) fixedly installed inside the main unit cabinet (1). A connecting plate (72) is installed on the movable end of the linear drive structure (71). A movable electrode (73) is installed on the top of the connecting plate (72). A sphere (76) is sleeved on the outside of the movable electrode (73).

3. The material testing technology according to claim 2, characterized in that, The inner wall of the sphere (76) is integrally formed with a guide block (75). An arc-shaped groove is provided on the outer side of the movable electrode (73) at one end of the guide block (75). A limiting disk (713) is integrally formed on the top and middle outer sides of the outer surface of the movable electrode (73). The end face of the limiting disk (713) near the sphere (76) is arc-shaped. A hole is provided in the middle of the fixed electrode (4). The maximum diameter of the limiting disk (713) at the bottom of the sphere (76) is smaller than the inner diameter of the hole. A groove (712) is provided at the bottom of the outer surface of the sphere (76).

4. The material testing technology according to claim 2, characterized in that, The linear drive structure (71) is composed of a drive motor and a lead screw, wherein the lead screw and the connecting plate (72) are connected by threads, and the main unit cabinet (1) has a guide groove inside, and the connecting plate (72) is slidably connected inside the guide groove.

5. The material testing technology according to claim 3, characterized in that, An installation plate (77) is fixedly installed above the limiting plate (713) at the top of the sphere (76). A spiral column (78) is fixedly installed at the top of the installation plate (77). A rotating ring (79) is connected to the top of the outer surface of the spiral column (78). A fixed plate (74) is movably connected to the bottom of the rotating ring (79), and the fixed plate (74) is fixedly installed on the transparent sleeve (3). A connecting arm (710) is movably provided at the top of the rotating ring (79), and an L-shaped clamping arm (711) is movably provided at one end of the connecting arm (710).

6. The material testing technology according to claim 5, characterized in that, The mounting plate (77) has a groove at its top and a protrusion at its bottom, which is located inside the groove.

7. The material testing technology according to claim 3, characterized in that, The connecting electrode (5) has a snap-fit ​​groove (714) inside, and the cross-section of the snap-fit ​​groove (714) is concave.

8. The material testing technology according to claim 2, characterized in that, The upper part of the movable electrode (73) is a spiral section, and the lower part of the movable electrode (73) is a smooth rod section.

9. The material testing technology according to claim 1, characterized in that, The fixed electrode (4) has a U-shaped groove at its top, and the connecting electrode (5) is located inside the U-shaped groove.

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