A gas discharge tube

Abstract

The application discloses a gas discharge tube, and belongs to the technical field of discharge tubes. The gas discharge tube comprises an electrode, a ceramic tube wall and electronic powder. The electrode comprises an outer electrode and an inner electrode. The inner electrode is fixedly connected with the inner side wall of the outer electrode. The outer electrode is fixedly and sealingly connected with the ceramic tube. The inner electrode is in a groove shape. The groove opening of the inner electrode is arranged away from the outer electrode. The electronic powder is adhered to the bottom wall of the groove of the inner electrode. The inner electrode with the groove and the electrode powder adhered to the grid can effectively reduce the spatter probability of the electrode powder. Meanwhile, the inner electrode with high temperature resistance can avoid the formation of metal droplets. The groove of the inner electrode can avoid the accumulation of the electrode liquid and the electrode powder to form a conductive belt, and can avoid the discharge tube from being in a short circuit state for a long time. The discharge tube of the application will not fail in short circuit, and the service life of the discharge tube is effectively prolonged.

Description

Technical Field

[0001] This invention belongs to the field of discharge tube technology, and specifically relates to a gas discharge tube. Background Technology

[0002] The discharge tube is sealed with a metallized ceramic tube and metal electrodes. When the voltage applied to the two electrodes reaches a level that breaks down the gas inside the gas discharge tube, the gas discharge tube begins to discharge, causing the gas discharge tube to change from its high-resistance state to a conductive (short-circuit) state.

[0003] Discharge tubes, as commonly used surge protection components, play a crucial role in lightning protection for railway signaling safety equipment. However, during use, discharge tubes are prone to short-circuit faults, leading to signal upgrades and posing a risk to safe train operation. Current technology identifies the short-circuit fault in discharge tubes primarily as electrode material splashing onto the tube wall and accumulating to form a conductive band. This conductive band connects the upper and lower electrodes, causing a short circuit. Current improvements to discharge tubes only address the issue of conductive bands forming on the tube wall causing short circuits. These improvements employ methods such as cutting off the pathway on the tube wall to prevent electrode material from splashing onto the tube wall during discharge. Specifically... Figure 1 As shown, by creating blocking grooves on the electrode sidewalls and cutting the conductive strip in the tube wall, the passage in the tube wall can be severed. However, this design cannot reduce the probability of electrode material splashing, nor can it prevent electrode material from splashing to both sides and adhering to the tube wall. Existing technologies also employ methods such as... Figure 2 The electrodes shown are shielded to prevent the discharge material from splashing to both sides and forming a conductive band during discharge, but this still cannot solve the problem of electrode splashing.

[0004] However, multiple short-circuit studies of discharge tubes have revealed that the detachment of the electrode materials mainly involves two parts: electron powder and electrode metal. Electron powder detaches from the electrodes due to the arc force generated during discharge, flying towards the tube wall or between the electrodes to form a conductive band. Electrode metal melts during discharge due to heat and force, producing small metal particles that are pushed towards the tube wall and between the electrodes by the arc force, forming a conductive band. The conductive band between the electrodes is as follows: Figure 3 As shown, the electrode melts at high temperature, and molten droplets and electrode powder accumulate on the lower electrode surface, causing a short circuit between the upper and lower electrodes. Existing slotted and shielding designs cannot prevent the accumulation of conductive material between the discharge tube electrodes, making the discharge tube prone to short-circuit faults. Summary of the Invention

[0005] To address the above problems, the present invention provides a gas discharge tube, employing the following technical solution:

[0006] A gas discharge tube, the gas discharge tube comprising electrodes, a ceramic tube wall, and electron powder;

[0007] The electrode includes an outer electrode and an inner electrode. The sidewall of the inner electrode is fixedly connected to the inner sidewall of the outer electrode. The outer electrode is fixedly and sealed to a ceramic tube. The inner electrode is grooved, and the groove opening of the inner electrode is located away from the outer electrode. The electronic powder is bonded to the bottom wall of the groove of the inner electrode.

[0008] Furthermore, the inner electrode and the outer electrode are connected by ultra-high temperature welding technology.

[0009] Furthermore, the internal electrode material is a conductive and impact-resistant material.

[0010] Furthermore, the shape of the inner electrode sidewall is the same as that of the outer electrode inner sidewall, and the area of ​​the inner electrode sidewall is equal to or greater than that of the outer electrode inner sidewall.

[0011] Furthermore, a mesh is provided inside the groove of the inner electrode, the mesh is fixed on the inner wall of the groove, and the electronic powder is bonded to the mesh and the inner electrode.

[0012] Furthermore, the mesh is embedded in the bottom wall of the inner electrode groove, and the size of the mesh is the same as the size of the bottom wall of the inner electrode groove.

[0013] Furthermore, the mesh is integrally formed with the inner electrode.

[0014] Furthermore, the mesh is formed by cutting or pulse impact on the internal electrode.

[0015] Furthermore, the mesh is made of the same material as the inner electrode.

[0016] Furthermore, the surface of the mesh away from the inner electrode is roughened.

[0017] The beneficial effects of this invention are:

[0018] 1. The gas discharge tube of the present invention adopts an inner electrode with a groove and an electrode powder adhered to the mesh, which can effectively reduce the probability of electrode powder splashing. Even if electrode powder splashes, it will not splash and adhere to the side walls. At the same time, the high temperature resistant inner electrode can prevent the formation of metal droplets.

[0019] 2. The grooved design of the internal electrode prevents electrode droplets and electrode powder from falling in the same position, thus avoiding the accumulation of electrode liquid and electrode powder to form a conductive band and preventing the discharge tube from being in a short-circuit state for a long time. The discharge tube using this invention will not fail due to short circuit, effectively extending the service life of the discharge tube and forming a gas discharge tube with a short-circuit-free mode.

[0020] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of a discharge tube structure designed with slotting according to existing technology is shown;

[0023] Figure 2 A schematic diagram of a discharge tube structure based on existing technology's slotted and shielded design is shown.

[0024] Figure 3 A schematic diagram of the conductive strip structure of the discharge tube electrode according to the prior art is shown;

[0025] Figure 4 A schematic diagram of a gas discharge tube structure according to an embodiment of the present invention is shown;

[0026] Figure 5 A schematic diagram of a fault-free short-circuit life test for a gas discharge tube is shown.

[0027] In the diagram: 1. Ceramic tube; 2. External electrode; 3. Internal electrode; 4. Mesh. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.

[0030] Research has revealed that the accumulation and deposition of sputtered material in gas discharge tubes is formed by the impact of lateral pressure generated by electrostatic force, metal evaporation force, and arc contraction force on the molten pool during arc discharge, resulting in large particles being splashed out from the large liquid jet.

[0031] The flocculent material between the electrodes may be particles generated during the bubble explosion process in the molten pool, or it may be a product of the interaction between particles and metal vapor. When the local electrode surface instantaneously reaches the boiling temperature under the action of the arc plasma, bubbles filled with metal vapor will form in the early molten pool. Therefore, from the very beginning of the molten pool formation, relatively small metal droplets are ejected at relatively large angles. As the molten pool expands, its flow velocity increases, and the kinetic energy of the molten material accumulates, thus overcoming the surface free energy of the electrodes. Therefore, the molten metal is ejected from a relatively small angle in the form of relatively large droplets, easily forming flocculent material between the electrodes.

[0032] As the discharge continues, various particles inside move and diffuse, colliding with the electrodes and tube walls. With increasing internal temperature, the particle movement and diffusion accelerate. Under the influence of the electric field, they collide with the electrode surface, generating sputtering and forming various metal atoms and molecules. These react and combine with internal ions to form various sputtered materials. As these sputtered materials gradually accumulate on the electrode and tube wall surfaces, they can easily form flocculent material between the electrodes and a conductive film on the tube wall, thus affecting the internal discharge state and causing a deterioration in the protective performance of the gas discharge tube.

[0033] This invention addresses the problem that after a period of use, conductive material accumulates between the electrodes of a gas discharge tube, making it prone to short-circuit faults. By establishing a calculation model of the electric field of sputtered material on the electrode surface, the influence of different electrode structures on the internal electric field of the gas discharge tube is studied. Finally, a gas discharge tube is proposed that improves the protective performance of the gas discharge tube by changing the electrode structure.

[0034] A gas discharge tube, such as Figure 4As shown, the gas discharge tube includes an electrode, a ceramic tube 1, and electron powder. The sidewall of the electrode is sealed to the ceramic tube 1 to form a hollow, sealed space. The sealed space is filled with a certain amount of inert gas, such as argon or neon.

[0035] The inner wall of the electrode is grooved and a grid 4 is provided inside the groove. The grid 4 is fixed on the inner wall of the groove, and the electron powder is bonded to the grid 4 and the inner electrode 3.

[0036] The electrode arrangement consists of two sets, upper and lower. Each set includes an outer electrode 2 and an inner electrode 3. The sidewall of the inner electrode 3 is fixedly connected to the inner sidewall of the outer electrode 2. The outer electrode 2 is fixedly and sealed to the ceramic tube 1. Specifically, the sidewall of the outer electrode 2 can be welded to the wall of the ceramic tube 1. The inner electrode 3 is located inside the sealed space and is groove-shaped. The opening of the groove of the inner electrode 3 is located away from the outer electrode 2. The groove openings of the two sets of inner electrodes 3 are arranged opposite each other, and the side of the inner electrode 3 away from the groove opening is fixedly connected to the inner side of the outer electrode 2.

[0037] The external electrode 2 uses a conventional electrode material, such as an iron-nickel alloy. Iron-nickel alloy, a common electrode material, has excellent conductivity and is readily available as a common metallic conductive material. Furthermore, since the gas discharge tube requires good gas sealing, the iron-nickel alloy electrode material allows for welding to the wall of the ceramic tube 1, ensuring reliable welding. Through welding, the external electrode 2 can be tightly connected to the side wall of the ceramic tube 1 with sufficient welding strength, guaranteeing the gas tightness and service strength of the discharge tube.

[0038] Preferably, the external electrode 2 is made of tungsten-copper alloy. Tungsten-copper alloy has a high melting point and excellent resistance to ablation and peeling. Comparing the microstructure images of tungsten-copper alloy and iron-nickel alloy, it can be seen that under the same number of discharge cycles, the iron-nickel alloy anode surface is accompanied by many sputtered particles and molten blocks distributed at the electrode edge, while the cathode is in a molten state and the ablation is very smooth. The tungsten-copper alloy anode surface has relatively fewer sputtered particles, and the distribution is uneven, with the surface basically showing a grid pattern. The cathode ablation is not severe, with little overall change, but some ablation spots appear on the electrode surface. Overall, tungsten-copper alloy has stronger ablation resistance, which can reduce the generation of sputtered particles, thereby reducing the degree of electric field distortion inside the gas discharge tube and improving the protective performance of the gas discharge tube.

[0039] The inner electrode 3 has the same sidewall shape as the outer electrode 2, and the area of ​​the inner electrode 3's sidewall is equal to or greater than the area of ​​the outer electrode 2's inner sidewall. This means the inner electrode 3's sidewall and the outer electrode 2's inner sidewall are tightly fitted together, ensuring that the bottom surface of the outer electrode 2's protrusion only contacts the inner electrode 3 and not the discharge gas. Specifically, the inner electrode 3 and outer electrode 2 are connected using ultra-high temperature welding technology, resulting in a seamless connection between the outer electrode 2's protrusion and the inner electrode 3. The groove depth of the inner electrode 3 is 0.5–1 mm.

[0040] The inner electrode 3 is composed of a conductive and impact-resistant material, specifically a tungsten-copper alloy or a molybdenum-copper alloy. This impact-resistant material, while meeting conductivity requirements, also possesses a high melting point, effectively preventing the inner electrode 3 from melting and detaching during high-voltage discharge, thus avoiding the formation of small metal droplets. Since small metal droplets would drip onto the electrodes and solidify into a liquid conductive solid at room temperature, repeated accumulation would form a conductive band between the electrodes with splashed electrode powder, causing the two sets of inner electrodes 3 to connect, keeping the discharge tube in a short-circuit fault mode. Using a material with strong weldability and sealing properties for the outer electrode 2 and a highly impact-resistant material for the inner electrode 3 ensures the gas discharge tube's sealing while improving its impact resistance, preventing the formation of conductive bands on the electrodes, and effectively extending the service life of the gas discharge tube. (Groove mounting)

[0041] The mesh 4 is embedded in the bottom wall of the groove of the inner electrode 3, and the size of the mesh 4 is the same as that of the bottom wall of the groove of the inner electrode 3. The height of the mesh 4 is 0.1-0.2 mm. The mesh 4 is made of the same impact-resistant material as the inner electrode 3. The mesh 4 and the inner electrode 3 are manufactured by integral molding, specifically by cutting the bottom wall of the inner electrode 3 or by pulse impacting the bottom wall of the inner electrode 3. To increase the adhesion between the mesh 4 and the electrode powder, the surface of the mesh 4 away from the inner electrode 3 is roughened, specifically by grinding or shallow cutting the surface of the mesh 4.

[0042] To further enhance the adhesion between the electronic powder and the internal electrode 3 and the mesh 4, the electronic powder can be upgraded with a high adhesion performance formula.

[0043] Because the electrode powder is placed inside the groove of the inner electrode 3, and no electrode powder is placed on the outer surface of the inner electrode 3, the electrode powder will be blocked by the side wall of the inner electrode 3 during high-voltage discharge of the discharge tube, and will not splash onto the side wall of the ceramic tube 1, thus ensuring the fixation of the electrode powder. The electrode liquid generated by the inner electrode 3 will only drip along the side wall of the groove, avoiding the electrode powder and electrode liquid dripping at the same position, and further preventing the formation of the electrode conductive band.

[0044] Electron powder, as the core material of gas discharge tubes, has a significant impact on the breakdown voltage of the tubes. By selecting suitable electron powder, the operational protection performance of the gas discharge tube can be altered. Simultaneously, the electron powder must possess high emission efficiency, strong resistance to ion bombardment, and minimal sputtering. Its composition not only affects the DC breakdown voltage but also directly influences other performance parameters of the discharge tube.

[0045] Specifically, in this embodiment of the invention, electron powder containing materials such as K2SiO3, Ni, NaBr, Al, Na2SiO3, and BaTiO3 is selected to improve the operational protection performance of the gas discharge tube. This is mainly achieved by increasing the ratio of barium carbonate and aluminum powder, followed by corresponding cumulative discharge experiments to compare the ablation characteristics of the electrode surface before and after the improvement. It can be seen that before the improvement, the electron powder sputters and forms various molten materials and protrusions during multiple discharges, causing changes in the internal electric field and leading to changes in the corresponding discharge process, resulting in deterioration of the operational protection performance. After the improvement, after multiple discharges, the electron powder distribution is more uniform, exhibiting stronger sputtering resistance, less sputtered material on the electrode surface, and a smaller number of ablation pits, thus slowing down the deterioration process of the gas discharge tube's operational protection performance. This indicates that selecting electron powder with low work function and strong sputtering resistance can delay its consumption process, stabilize voltage changes during the discharge process, and improve the operational protection performance of the gas discharge tube.

[0046] To test the fault-free short-circuit lifespan and fault short-circuit failure resistance of the gas discharge tube of the present invention, a discharge tube fast switching test platform was used to conduct continuous fast triggering conduction and disconnection experiments on the discharge tube to test the working life of the discharge tube in fault-free short-circuit mode.

[0047] like Figure 5 As shown, the discharge tube fast switching test platform uses a continuous oblique wave to rapidly energize the discharge tube. The waveform amplitude is the conduction value of the discharge tube. When the insulation resistance at both ends of the discharge tube is less than 10MΩ, the continuous switching and conduction test on the discharge tube ends. The discharge tube of this invention, the discharge tube with a slotted design, the discharge tube with a slotted and shielded design, and the ordinary untreated discharge tube were all subjected to continuous switching and conduction tests. The maximum number of times continuous discharge could achieve a short circuit was recorded to obtain the fault-free short-circuit life of different test discharge tubes. The test results are shown in the table below:

[0048]

[0049] The test results show that the fault-free short-circuit life of the gas discharge tube of the present invention is much higher than that of the discharge tube in the prior art.

[0050] The grooved inner electrode and the mesh-adhered electrode powder effectively reduce the probability of electrode powder splashing. Even if splashing occurs, the electrode powder will not adhere to the side walls. Simultaneously, the high-temperature resistant inner electrode design prevents the formation of molten metal droplets. The grooved design of the inner electrode also prevents electrode droplets and electrode powder from falling in the same location, avoiding the accumulation of electrode liquid and electrode powder to form a conductive band, and preventing the discharge tube from being in a short-circuit state for a long time. The discharge tube using this invention will not experience short-circuit failure, effectively extending the service life of the discharge tube and forming a short-circuit-free gas discharge tube.

[0051] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas discharge tube, characterized by, The gas discharge tube includes electrodes, a ceramic tube (1), and electron powder; The electrode includes an outer electrode (2) and an inner electrode (3). The sidewall of the inner electrode (3) is fixedly connected to the inner sidewall of the outer electrode (2). The outer electrode (2) is fixedly and sealed to the ceramic tube (1). The inner electrode (3) is grooved. The groove opening of the inner electrode (3) is located away from the outer electrode (2). The electronic powder is bonded to the bottom wall of the groove of the inner electrode (3). The outer side of the inner electrode (3) is not covered with electronic powder. The outer electrode (2) is made of a conductive metal material. The material of the inner electrode (3) is a conductive and impact-resistant material. The depth of the groove is greater than the thickness of the electronic powder layer. The inner electrode (3) has the same sidewall shape as the outer electrode (2) and the area of ​​the inner electrode (3) sidewall is equal to or greater than the area of ​​the outer electrode (2) sidewall. A grid (4) is provided inside the groove of the inner electrode (3). The grid (4) is fixed on the inner wall of the groove and the electron powder is bonded to the grid (4) and the inner electrode (3). The grid (4) is embedded in the bottom wall of the groove of the inner electrode (3) and the size of the grid (4) is the same as the size of the bottom wall of the groove of the inner electrode (3).

2. The gas discharge tube of claim 1, wherein The inner electrode (3) and the outer electrode (2) are connected by ultra-high temperature welding technology.

3. The gas discharge tube of claim 1, wherein The mesh (4) is integrally formed with the inner electrode (3).

4. The gas discharge tube according to claim 1 or 3, characterized in that The grid (4) is formed by cutting or pulse impact on the inner electrode (3).

5. The gas discharge tube of claim 1 or 3, wherein The mesh (4) is made of the same material as the inner electrode (3).

6. The gas discharge tube of claim 1 or 3, wherein The surface of the mesh (4) away from the inner electrode (3) is roughened.

Images