GAS DISCHARGE TUBE

Abstract

 The present invention discloses a gas discharge tube, which belongs to the technical field of discharge tubes. The gas discharge tube includes electrodes, a ceramic tube wall and electronic powder; the electrodes include an outer electrode and an inner electrode, a side wall of the inner electrode is fixedly connected to an inner side wall of the outer electrode, the outer electrode is fixedly connected to a ceramic tube in a sealing manner, the inner electrode is in a groove shape, a groove opening of the inner electrode is arranged away from the outer electrode, and the electronic powder is bonded to a bottom wall of the groove of the inner electrode. In the gas discharge tube of the present invention, the arrangement of the inner electrode arranged with the groove and the electrode powder bonded to a grid can effectively reduce the sputtering probability of the electrode powder, and in addition, the arrangement of the inner electrode with high temperature resistance can avoid the formation of metal droplets. The arrangement of the groove of the inner electrode avoids accumulation and stacking of electrode liquid and the electrode powder to form a conductive strip, thereby preventing the discharge tube from being in a short-circuit state for a long time. By adopting the discharge tube of the present invention, no fault short-circuit failure occurs, and the service life of the discharge tube is effectively prolonged.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of discharge tubes, in particular to a gas discharge tube.

BACKGROUND

[0002] The discharge tube is sealed and packaged by using a metalized ceramic tube and a metal electrode. When a voltage applied to two electrode ends reaches a voltage that breaks down a gas in the gas discharge tube, the gas discharge tube starts to discharge, so that the gas discharge tube changes from a high resistance state thereof to a turned-on (short-circuit) state.

[0003] A discharge tube, as a common surge protection element, has an important role in ground lightning protection of a railway signal safety device. However, the discharge tube is prone to be in a fault short-circuit mode during use, and a signal upgrade caused thereby causes a safety traveling risk. In the prior art, it is considered that the fault short-circuit mode of the discharge tube is mainly because electrode substances are sputtered onto the discharge tube wall and are accumulated to form a conductive strip, and the conductive strip connects upper and lower electrodes to cause a short circuit fault of the discharge tube. Currently, the improved discharge tube is only improved for the problem of short circuit caused by the conductive strip formed on the discharge tube wall, in which sputtering of electrode substances onto the tube wall during discharge is prevented by cutting the circuit of the tube wall. Specifically, as shown in Fig. 1, by providing a blocking groove on a side wall of an electrode, the circuit of the tube wall can be cut off by cutting off a conductive strip of the tube wall. However, this design cannot reduce the sputtering probability of the electrode substances, and cannot prevent the electrode substances from sputtering on both sides and attaching to the tube wall. The prior art also adopts the shielding processing of the electrodes as shown in Fig. 2, which can prevent discharge substances from sputtering to both sides during discharge between the electrodes to form a conductive strip, but the problem of electrode sputtering still cannot be solved.

[0004] However, after repeated discharge tube short-circuit research, it can be determined that electrode substances of a discharge tube are mainly divided into two parts: electronic powder and electrode metal. Due to the action of the arc force generated by discharge, the electron powder attached to the electrodes is detached, and is sputtered towards a tube wall or the electrodes to form a conductive strip; and due to the heat of the electrodes and the action of a force during discharge, the metal of the electrodes is melted to generate small metal particles, which are pushed to the tube wall and the electrodes by the action of the arc force to form a conductive strip between the electrodes. The conductive strip between the electrodes is as shown in Fig. 3, the electrodes melt at a high temperature, molten droplets and electrode powder drop are gradually accumulated on the surface of the electrodes at a lower position, causing a short circuit caused by connection between the upper and lower electrodes. In the prior art, both the groove design and the shielding design cannot avoid accumulation of conductive substances between the electrodes of a discharge tube, so that the discharge tube is still easy to be in a fault short-circuit mode.

SUMMARY

[0005] In view of the described problems, the present invention provides a gas discharge tube, which adopts the following technical solution:

a gas discharge tube, in which the gas discharge tube includes electrodes, a ceramic tube wall and electronic powder;

the electrodes include an outer electrode and an inner electrode, a side wall of the inner electrode is fixedly connected to an inner side wall of the outer electrode, the outer electrode is fixedly connected to the ceramic tube in a sealing manner, the inner electrode is in a groove shape, a groove opening of the inner electrode is arranged away from the outer electrode, and the electronic powder is bonded to a bottom wall of the groove of the inner electrode.

[0006] Further, the inner electrode and the outer electrode are connected by means of an ultra-high temperature welding technique.

[0007] Further, the material of the inner electrode is a conductive impact-resistant material.

[0008] Further, the shape of the side wall of the inner electrode is the same as the shape of the inner side wall of the outer electrode, and the area of the side wall of the inner electrode is equal to or larger than the area of the inner side wall of the outer electrode.

[0009] Further, a grid is provided in the groove of the inner electrode, the grid is fixed on an inner wall of the groove, and the electronic powder is bonded to the grid and the inner electrode.

[0010] Further, the grid is embedded in the bottom wall of the groove of the inner electrode, and the size of the grid is the same as that of the bottom wall of the groove of the inner electrode.

[0011] Further, the grid and the inner electrode are integrally formed.

[0012] Further, the grid is formed by cutting or impacting, by means of an impulse method, the inner electrode.

[0013] Further, the grid and the inner electrode are made of the same material.

[0014] Further, a surface of a side of the grid away from the inner electrode is subjected to rough processing.

[0015] The present invention has the following beneficial effects:

1. The gas discharge tube of the present invention uses the inner electrode arranged with the groove and the electrode powder arranged to be bonded to the grid, which can effectively reduce the sputtering probability of the electrode powder. Even if the electrode powder sputters, the electrode powder does not sputter and adhere to the side walls on both sides. In addition, the inner electrode arranged with high temperature resistance can avoid the formation of metal droplets.

2. The arrangement of a groove of the inner electrode also prevents the electrode droplets and the electrode powder from falling at the same position, avoiding accumulation and stacking of the electrode liquid and the electrode powder to form a conductive strip, thereby preventing the discharge tube from being in a short-circuit state for a long time. By means of the discharge tube of the present invention, a fault short-circuit failure does not occur, the service life of the discharge tube is effectively prolonged, and a gas discharge tube without a short-circuit mode is formed.

[0016] Additional features and advantages of the present invention are illustrated in the following description, which partially will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention may be achieved and obtained by the structure pointed out in the description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the accompanying drawings required for describing the embodiments or in the prior art are briefly introduced as follows. Obviously, the accompanying drawings in the following description show merely some embodiments of the present invention, and for a person of ordinary skill in the art, other drawings may also be obtained according to these drawings without any inventive effort.

Fig. 1 shows a schematic diagram of a discharge tube according to a slotting design in the prior art;

Fig. 2 shows a schematic structural diagram of a discharge tube according to a groove design and a shielding design in the prior art;

Fig. 3 shows a schematic diagram of a conductive strip of electrodes of a discharge tube according to the prior art;

Fig. 4 is a schematic structural diagram of a gas discharge tube according to the embodiments of the present invention;

Fig. 5 shows a schematic diagram of a service life test of a gas discharge tube without a short-circuit fault.

[0018] In the drawings: 1, ceramic tube; 2, outer electrode; 3, inner electrode; 4, grid.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clear, the technical solutions of the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are a part rather than all of the embodiments of the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall belong to the scope of protection of the present invention.

[0020] It should be noted that the terms "first" and "second" in the present application are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or order. It should be understood that the data so used may be interchanged where appropriate for the embodiments of the present application described herein. In the present application, the orientation or position relationships indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. are based on the orientation or position relationships shown in the drawings.

[0021] It has been found through research that the accumulation and deposition of sputtered materials of a gas discharge tube are formed by the impact of a side pressure generated by an electrostatic force, a metal evaporation force and an electric arc contraction force on a molt pool during the arc discharge, resulting in large particles being sputtered from the large liquid jet.

[0022] The floccule between electrodes may be particles generated during bubble explosion in the molt pool, and may also be a product of interaction between the particles and metallic vapor. When the local electrode surface instantaneously reaches a boiling temperature under the action of arc plasma, bubbles full of metallic vapor are formed in the molt pool at an early stage. As a result, relatively smaller metal droplets are sputtered out at a relatively larger angle as the bubbles are initially formed in the molt pool. With the expansion of the molt pool, the flow speed of the molt pool increases, and the kinetic energy of a molten material accumulates more, thereby overcoming the surface free energy of the electrodes. The metal molten material is thus ejected in the form of relatively large droplets in a smaller angle, tending to form floccule between the electrodes.

[0023] With the continuous discharge, various particles in the interior move and diffuse, and collide with the electrodes and the tube wall. With the rising of the interior temperature, the particle movement and the diffusion speed accelerate. Under the action of the electric field, the particles impact the surface of the electrodes to cause sputtering, so as to form various metal atoms and molecules, which react and combine with ions in the interior to form various sputtered materials. As the sputtered materials are gradually accumulated on the surfaces of the electrodes and the tube wall, floccule is easily formed between the electrodes, and a conductive film is easily formed on the tube wall, thereby affecting the internal discharging state, and causing deterioration of the action protection performance of the gas discharge tube.

[0024] For the problem that after a gas discharge tube is used for a certain period of time, conductive substances are accumulated between electrodes of the discharge tube, and the gas discharge tube is likely to be in a fault short-circuit mode, in the present invention, by establishing an electric field calculation model of sputtered materials on the surface of the electrodes, the influence of different electrode structures on the electric field inside the gas discharge tube is studied, and finally, a gas discharge tube is provided. By changing the structure of the electrodes, the action protection performance of the gas discharge tube is improved.

[0025] A gas discharge tube, as shown in Fig. 4, in which the gas discharge tube includes electrodes, a ceramic tube 1 and electronic powder; the side walls of the electrodes are connected to the ceramic tube 1 in a sealing manner, so as to form a sealed space with a hollow interior; and the sealed space is filled with a certain amount of inert gas, such as argon gas and neon gas.

[0026] The inner side walls of the electrodes are of a groove shape, a grid 4 is provided inside the groove of the electrodes, the grid 4 is fixed on the inner wall of the groove, and the electronic powder is bonded to the grid 4 and the inner electrode 3.

[0027] There are an upper set of electrodes and a lower set of electrodes, each set of electrodes include an outer electrode 2 and an inner electrode 3, a side wall of the inner electrode 3 is fixedly connected to an inner side wall of the outer electrode 2, and the outer electrode 2 is fixedly connected to the ceramic tube 1 in a sealing manner, specifically, the side wall of the outer electrode 2 can be welded to the side wall of the ceramic tube 1. The inner electrode 3 is located inside the sealed space, the inner electrode 3 is in the shape of a groove, the groove opening of the inner electrode 3 is arranged away from the outer electrode 2, the groove openings of the two sets of inner electrodes 3 are arranged opposite to each other, and the side of the inner electrode 3 away from the groove opening is fixedly connected to the inner side surface of the outer electrode 2.

[0028] The outer electrode 2 is made of a conventional electrode material, which may be an iron-nickel alloy. A common electrode material, such as an iron-nickel alloy, has an excellent electrical conductivity, and is simple and readily available as a common metal conductive material. In addition, as the gas discharge tube needs a good gas sealing performance, an electrode material of the iron-nickel alloy can achieve a welding processing with the ceramic tube 1 wall, and can ensure the reliability of welding with the ceramic tube 1 wall. By means of the welding processing, the outer electrode 2 can be tightly connected to the side wall of the ceramic tube 1, and has sufficient welding strength, thereby ensuring the gas tightness and the use strength of the discharge tube.

[0029] Preferably, the outer electrode 2 is made of a tungsten-copper alloy, which has a high melting point and excellent anti-ablation and anti-stripping properties. Comparing microscopic topographic graphs of a tungsten-copper alloy and an iron-nickel alloy, it can be determined that under the same number of times of discharges, the surface of an iron-nickel alloy anode has many sputtered particles and melting blocks distributed at an edge of an electrode, and a cathode is in a molten state and is ablated smoothly; the surface of a tungsten-copper alloy anode has a relatively small amount of sputtered materials, which are distributed unevenly, and the surface is basically in a grid shape; however, the cathode is ablated slightly and does not change greatly as a whole, and some ablation spots appear and are distributed on the surface of the electrode. As a whole, the tungsten-copper alloy has better anti-ablation performance, and can reduce the generation of sputtered materials, thereby reducing the degree of distortion of an internal electric field of the gas discharge tube, and improving the action protection performance of the gas discharge tube.

[0030] The shape of the side wall of the inner electrode 3 is the same as the shape of the inner side wall of the outer electrode 2, and the area of the side wall of the inner electrode 3 is equal to or greater than the area of the inner side wall of the outer electrode 2, i.e. the side wall of the inner electrode 3 is closely attached to the inner side wall of the outer electrode 2, such that the bottom surface of a boss of the outer electrode 2 does not contact the discharge gas and only contacts the inner electrode 3. Specifically, the inner electrode 3 and the outer electrode 2 are connected by using an ultra-high temperature welding technique, so that the boss of the outer electrode 2 is seamlessly combined with the inner electrode 3. The depth of the groove of the inner electrode 3 is 0.5-1 mm.

[0031] The inner electrode 3 is made of a conductive impact resistant material. Specifically, the inner electrode 3 is made of a tungsten-copper alloy or a molybdenum-copper alloy, the impact resistant material has a high melting point characteristic under the condition of satisfying the conductivity, and can effectively prevent the inner electrode 3 from melting and falling off during high-voltage discharge, thereby preventing the formation of metal droplets. As small metal droplets may drop on the electrodes and are solidified into a liquid conductive solid at a room temperature, multiple accumulations thereof may form a conductive strip between electrodes with the sputtered electrode powder, so that two sets of inner electrodes 3 are connected, and the discharge tube is always in a fault short-circuit mode. By using a material having a strong welding sealing property as the outer electrode 2 and using a high impact resistant material as the inner electrode 3, the impact resistance performance of the gas discharge tube is improved while ensuring the sealing property of the gas discharge tube, the formation of a conductive strip between electrodes is avoided, and the service life of the gas discharge tube is effectively prolonged.

[0032] The grid 4 is embedded in the bottom wall of the groove of the inner electrode 3, the size of the grid 4 is consistent with the size of the bottom wall of the groove of the inner electrode 3, and the height of the grid 4 is 0.1-0.2 mm. The grid 4 is made of the same impact resistant material as the inner electrode 3, and the grid 4 and the inner electrode 3 are manufactured in an integral forming manner, and specifically, the bottom wall of the inner electrode 3 is cut or the bottom wall of the inner electrode 3 is subjected to pulse impulsion, so as to manufacture the grid and the inner electrode. In order to increase the adhesion between the grid 4 and the electrode powder, the surface of a side of the grid 4 away from the inner electrode 3 is subjected to rough processing, specifically, the surface of the grid 4 may be polished or subjected to shallow cutting processing.

[0033] In order to further increase the bonding performance of the electronic powder with the inner electrode 3 and the grid 4, a formulation with high adhesion performance can be used for upgrading the electronic powder.

[0034] As the electrode powder is provided in the groove of the inner electrode 3 and the electrode powder is not provided on the outer side surface of the inner electrode 3, when the discharge tube discharges under a high voltage, the electrode powder may be blocked by the side wall of the inner electrode 3 and may not sputter onto the side wall of the ceramic tube 1, thereby ensuring the fixation of the electrode powder. The electrode liquid produced by the inner electrode 3 only drops along the side wall of the groove, thereby preventing the electrode powder and the electrode liquid from falling at the same position, and further preventing the conductive strip from being formed between electrodes.

[0035] The electronic powder, as a core material of the gas discharge tube, has a great influence on the breakdown voltage of the gas discharge tube. By selecting appropriate electronic powder, the action protection performance of the gas discharge tube can be changed. Meanwhile, it is required that the electronic powder has a high emission efficiency, a strong ion bombardment resistance and less sputtering. The components thereof not only affect the DC breakdown voltage, but also directly affect other performance parameters of the discharge tube.

[0036] Specifically, in the embodiments of the present invention, the electronic powder containing materials such as K2SiO3, Ni, NaBr, Al, Na2SiO3, and BaTiO3 is selected, so as to improve the action protection performance of the gas discharge tube. The proportion of barium carbonate and aluminum powder is mainly increased, and then a corresponding cumulative discharge experiment is performed to compare the ablation characteristics of the electrode surface before and after the improvement. It can be determined therefrom that, in the process of multiple times of discharging, the electronic powder before improvement may be sputtered to form various molten materials and protrusions, which causes a change in an internal electric field, resulting in a change in a discharging process corresponding thereto, and deterioration of the action protection performance; however, after the improvement, after multiple times of discharging, the electronic powder is distributed evenly, the anti-sputtering capability is relatively strong, the sputtered material on the surface of the electrodes is small, and a small portion of the ablation pit exists, so that the deterioration progress of the action protection performance of the gas discharge tube can be delayed. This indicates that selection of the electronic powder having a low work function and a strong anti-sputtering capability can delay a consumption process thereof, stabilizing a voltage change in the discharging process, and improving the action protection performance of the gas discharge tube.

[0037] In order to test the service life of the gas discharge tube without a fault short-circuit and a failure resistance of a fault short-circuit of the gas discharge tube in the present invention, a quick switch test platform of the discharge tube is used to perform continuous quick triggering on and off tests on the discharge tube, so as to test the service life of the discharge tube in a non-fault short-circuit mode.

[0038] As shown in Fig. 5, the quick switch test platform of the discharge tube quickly electrifies the discharge tube by using continuous oblique angle waves, the amplitude of the waveform is a turning-on value of the discharge tube, and when the insulation resistance at both ends of the discharge tube is less than 10MQ, continuous on-off and turning-on experiments on the discharge tube are finished. All of the discharge tube of the present invention, a discharge tube using a groove design, and a discharge tube using a groove and shielding design, and an ordinary discharge tube without designing are subjected to continuous on/off and turning-on experiments, the maximum number of times that continuous discharging can reach a non-short-circuit is recorded, so as to obtain a service life without a fault short-circuit of different tested discharge tubes, the test results are shown in the following table:

	Discharge tube of the present invention	Discharge tube using a groove design	Discharge tube using a groove and shielding design	Ordinary discharge tube without designing
Service life without a fault short-circuit	1 million times	200 thousand times	300 thousand times	50 thousand times

[0039] It can be determined from the test results that the service life without a fault short-circuit of the gas discharge tube of the present invention is longer than that of the discharge tube in the prior art.

[0040] The inner electrode arranged with the groove and the electrode powder arranged to be bonded to the grid can effectively reduce the sputtering probability of the electrode powder. Even if the electrode powder sputters, the electrode powder does not sputter and adhere to the side walls on both sides. In addition, the inner electrode arranged with high temperature resistance can avoid the formation of metal droplets. The arrangement of a groove of the inner electrode also prevents the electrode droplets and the electrode powder from falling at the same position, avoiding accumulation and stacking of the electrode liquid and the electrode powder to form a conductive strip, thereby preventing the discharge tube from being in a short-circuit state for a long time. By means of the discharge tube of the present invention, a fault short-circuit failure does not occur, the service life of the discharge tube is effectively prolonged, and a gas discharge tube without a short-circuit mode is formed.

[0041] Although the present invention is described in detail with reference to the described embodiments, those of ordinary skill in the art should understand that they may still make modifications to the technical solutions described in the described embodiments or make equivalent replacements to some technical features thereof; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas discharge tube, wherein the gas discharge tube comprises electrodes, a ceramic tube (1) wall and electronic powder;
the electrodes comprise an outer electrode (2) and an inner electrode (3), a side wall of the inner electrode (3) is fixedly connected to an inner side wall of the outer electrode (2), the outer electrode (2) is fixedly connected to a ceramic tube (1) in a sealing manner, the inner electrode (3) is in a groove shape, a groove opening of the inner electrode (3) is arranged away from the outer electrode (2), and the electronic powder is bonded to a bottom wall of the groove of the inner electrode (3).

2. The gas discharge tube according to claim 1, wherein the inner electrode (3) and the outer electrode (2) are connected by using an ultra-high temperature welding technique.

3. The gas discharge tube according to claim 1, wherein the material of the inner electrode (3) is a conductive impact-resistant material.

4. The gas discharge tube according to claim 1, wherein the shape of the side wall of the inner electrode (3) is the same as the shape of the inner side wall of the outer electrode (2), and the area of the side wall of the inner electrode (3) is equal to or larger than the area of the inner side wall of the outer electrode (2).

5. The gas discharge tube according to claim 2, wherein a grid (4) is provided in the groove of the inner electrode (3), the grid (4) is fixed on an inner wall of the groove, and the electronic powder is bonded to the grid (4) and the inner electrode (3).

6. The gas discharge tube according to claim 5, wherein 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 that of the bottom wall of the groove of the inner electrode (3).

7. The gas discharge tube according to claim 5, wherein the grid (4) and the inner electrode (3) are integrally formed.

8. The gas discharge tube according to any one of claims 5-7, wherein the grid (4) is formed by cutting or impacting, by means of an impulse method, the inner electrode (3).

9. The gas discharge tube according to any one of claims 5-7, wherein the grid (4) and the inner electrode (3) are made of the same material.

10. The gas discharge tube according to any one of claims 5-7, wherein a surface of a side of the grid (4) away from the inner electrode (3) is subjected to rough processing.

Drawing