Gas discharge tube that generates distorted electric field

Abstract

The invention discloses a gas discharge tube capable of generating a distorted electric field, comprising an insulating tube body and end electrodes sealed at both ends of the insulating tube body, wherein a discharge gap located between the end electrodes is formed in the insulating tube body; the end electrode comprises an electron emission surface located at one side of the insulating tube body and coated with an electron emission coating; a groove and a plurality of grooves are arranged on the electron emission surface, wherein the groove is located at the center of the electron emission surface, and the plurality of grooves extend outward from the groove; in the gas discharge tube having the above structure, when the gas discharge tube operates under transient overvoltage of a power supply system, charges are enriched at the grooves and the grooves, thereby forming a distorted electric field with twist and deformation in the discharge gap, wherein the distorted electric field causes the electron emission point on the electron emission surface to drift rapidly, thereby avoiding long-term local discharge of the electron emission surface, thereby solving the problem of melting of the end electrode or damage of the insulating tube body caused by long-term local discharge of the electron emission surface, and effectively improving the service life of the gas discharge tube.

Description

Technical Field

[0001] The present invention relates to the technical field of gas discharge tubes, and in particular to a gas discharge tube capable of generating a distorted electric field. Background Art

[0002] At present, the gas discharge tubes commonly used in the lightning overvoltage protection scheme of low-voltage AC and DC power distribution systems are cylindrical parallel gap discharge tubes, such as Fig. 9 and Fig.10 As shown, the gas discharge tube includes a metal electrode 5 and a ceramic tube 6. A closed space is formed in the ceramic tube 6, and the space is filled with an inert gas. An auxiliary triggering graphite electrode 8 is drawn on the inner wall of the ceramic tube 6. The metal electrode 5 has an electron emission surface 50. The electron emission surfaces 50 on the two metal electrodes 5 form a cylindrical parallel discharge gap 7.

[0003] When the lightning overvoltage is applied to the two metal electrodes 5, the spatial electric field of the cylindrical discharge gap 7 is a uniform parallel electric field. At this time, due to the very high voltage rise rate formed by the lightning overvoltage, the electric field strength at both ends of the auxiliary triggering graphite electrode 8 is the largest, and the nearby inert gas is first ionized and broken down to form a plasma arc. The lightning voltage with a very high rise rate causes the discharge current in the discharge tube to rise at a very high rate. The plasma arc formed at both ends of the graphite electrode 8 quickly expands to the cylindrical discharge gap 7, resulting in the formation of discharge plasma in the cylindrical discharge gap 7 and participating in the discharge of current. At this time, the uniform parallel electric field is beneficial to the life of the emission surface on the metal electrode 5.

[0004] However, when the gas discharge tube is connected to the low voltage AC or DC power distribution system, it not only has to withstand the lightning overvoltage, but also the transient overvoltage that may be generated by the power distribution system.

[0005] Compared with the lightning strike voltage, the transient overvoltage generated by the power distribution system has a relatively low voltage rise rate. The position where the inert gas is first ionized and broken down is at a certain point in the cylindrical discharge gap area. The low voltage rise rate leads to a low current rise rate formed by the discharge plasma in the discharge gap after ionization and breakdown. The electron emission on the electron emission surface 50 on the metal electrode 5 changes from the surface emission of the lightning strike overvoltage to point emission. The emission point drifts continuously in the area of ​​the electron emission surface 50, and the uniform parallel electric field has no effect on the drift of the emission point. At this time, if the overcurrent drift rate formed by the transient overvoltage is too slow, a local discharge is formed, which will cause the metal at the emission point to be locally overheated and melted, and the molten metal will bulge along the direction of the electric field under the action of the parallel electric field in the discharge gap, causing the discharge gap to short-circuit, damage the gas discharge tube, and may cause other damage to the power supply system. If the local overheating point is close to the inner wall of the ceramic tube 6, the ceramic tube 6 will burst, causing the gas discharge tube to fail and be damaged. Summary of the invention

[0006] The object of the present invention is to solve the above-mentioned technical problems and provide a gas discharge tube which can effectively prevent partial discharge and generate a distorted electric field.

[0007] In order to achieve the above-mentioned purpose, the present invention discloses a gas discharge tube capable of generating a distorted electric field, comprising an insulating tube body and end electrodes sealed at both ends of the insulating tube body, wherein a discharge gap is formed in the insulating tube body and located between the two end electrodes; the end electrode comprises an electron emission surface located on one side of the insulating tube body and coated with an electron emission coating; a groove and a plurality of grooves are arranged on the electron emission surface, wherein the groove is located at the central part of the electron emission surface, and the plurality of grooves extend outward from the groove.

[0008] Preferably, the insulating tube body is a metallized ceramic tube.

[0009] Preferably, a graphite electrode for assisting in triggering gas ionization is provided on the inner wall of the insulating tube.

[0010] Preferably, a plurality of the grooves are evenly spaced and arranged around the groove.

[0011] Preferably, one end of the groove is communicated with the recess, and the other end of the groove extends outward from the recess.

[0012] Preferably, the groove is in a linear structure or a curved structure.

[0013] Preferably, the number of the grooves is three or four.

[0014] Preferably, the groove comprises a plurality of annular grooves arranged around the groove.

[0015] Preferably, there are two grooves.

[0016] Compared with the prior art, the present invention is a gas discharge tube capable of generating a distorted electric field, comprising an insulating tube body and end electrodes sealed at both ends of the insulating tube body, wherein the end electrodes are provided with an electron emission surface, wherein a groove and a plurality of grooves distributed around the groove are provided on the electron emission surface. When the gas discharge tube operates under transient overvoltage of a power supply system, due to the presence of the groove and the plurality of grooves, after the inert gas in the insulating tube body is ionized, charges are enriched at the groove and the groove, and the charge enrichment density gradually decreases from the groove outward, thereby forming a distorted and deformed distorted electric field in the discharge gap. The distorted electric field causes the electron emission point on the electron emission surface to drift rapidly, thereby avoiding long-term local discharge of the electron emission surface, thereby solving the problem of melting of the end electrode or damage to the insulating tube body caused by long-term local discharge of the electron emission surface, and effectively improving the service life of the gas discharge tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 FIG. 1 is a schematic longitudinal cross-sectional view of a gas discharge tube in an embodiment of the present invention.

[0018] Figure 2 for Figure 1 Enlarged schematic diagram of part D in the middle.

[0019] Figure 3 FIG. 4 is a schematic diagram of the three-dimensional structure of the terminal electrode in one embodiment of the present invention.

[0020] Figure 4 for Figure 3 Top view of the .

[0021] Figure 5 FIG. 4 is a schematic diagram of the three-dimensional structure of the terminal electrode in another embodiment of the present invention.

[0022] Figure 6 for Figure 5 Top view of the .

[0023] Figure 7 FIG. 4 is a schematic diagram of the three-dimensional structure of the terminal electrode in another embodiment of the present invention.

[0024] Figure 8 for Figure 7 Top view of the .

[0025] Fig. 9 A schematic longitudinal section diagram of a gas discharge tube in the prior art.

[0026] Fig.10 for Fig. 9 Schematic cross-section of . DETAILED DESCRIPTION

[0027] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0028] like Figures 1 to 4 The present embodiment discloses a gas discharge tube capable of generating a distorted electric field, comprising an insulating tube body 1 and end electrodes 2 sealed at both ends of the insulating tube body 1, wherein a discharge gap 3 is formed in the insulating tube body 1 between the end electrodes 2. The end electrode 2 comprises an electron emission surface 20 located at one side of the insulating tube body 1 and coated with an electron emission coating, wherein a groove 200 and a plurality of grooves 201 are provided on the electron emission surface 20, wherein the groove 200 is located at the center of the electron emission surface 20, and the plurality of grooves 201 extend outward from the groove 200.

[0029] Preferably, the insulating tube body 1 is a metallized ceramic tube, and a graphite electrode 4 for assisting in triggering gas ionization is also provided on the inner wall of the insulating tube body 1 .

[0030] The working principle of the gas discharge tube in the above embodiment is:

[0031] Please refer again Figures 1 to 4 The insulating tube body 1 is filled with an inert gas, and a cylindrical discharge gap 3 is formed between the electron emission surfaces 20 of the two end electrodes 2. When an overvoltage (lightning voltage or transient overvoltage of the power distribution system) is applied to the two end electrodes 2, the inert gas is ionized, and the electron emission surfaces 20 on the two end electrodes 2 emit electrons, forming a discharge current connected to the ground through the discharge gap 3. At this time, since the charge on the electron emission surface 20 is enriched near the edge of the groove 200 and the groove 201 (such as Figure 4 ), and the charge on the electron emission surface 20 is enriched from the far end to the near end of the groove 200, that is, the charge density at the edge of the groove 200 and the groove 201 on the electron emission surface 20 is greater than that in other areas, and the charge density at the near end of the groove 200 is greater than that at the far end of the groove 200, such as Figure 4 As shown in , the charge density at point A and point B is greater than that at point C. Since point A is closer to the groove 200, the charge density at point A is greater than that at point B, so that the electric field strength in the discharge gap 3 is in a variable and deformed distribution, rather than a traditional uniform electric field, such as Figure 1 and Figure 2 , the density of the electric field line E changes in a non-uniform state with different sizes. Under the action of the electric field force, the ions in the plasma formed after the inert gas is ionized move in the direction of the electric field force, and the electrons emitted by the electron emission surface 20 move in the opposite direction of the electric field force to form a plasma current. At this time, since the electric field is abnormally distributed, the electric field force is also abnormally distributed. At the same time, due to the inertia of the movement of electrons and ions, the current path formed by the plasma is in a drifting state. The ions bombard the electron emission surface 20 to obtain electrons and recover to gas molecules, and during the bombardment, the electron emission surface 20 emits electrons again, causing the electron emission points on the electron emission surface 20 to drift, thereby avoiding local long-term discharge on the electron emission surface 20, and then effectively preventing the melting of the end electrode 2 or the rupture of the insulating tube body 1 caused by local long-term discharge, thereby improving the service life of the gas discharge tube.

[0032] Better, such as Figures 3 to 8 A plurality of grooves 201 are evenly spaced around the groove 200, so that the charge intensity change on the electron emission surface 20 is evenly distributed, thereby preventing the discharge arc from approaching the wall of the insulating tube body 1 due to excessive deviation of the electric field, thereby causing damage to the insulating tube body 1.

[0033] Furthermore, if Figures 3 to 6 , one end of the groove 201 is connected to the groove 200, and the other end of the groove 201 extends outward from the groove 200. Specifically, in this embodiment, the groove 201 is a straight-line structure or a curved structure. When the straight-line structure of the groove 201 is adopted, Figure 3 and Figure 4 , four grooves 201 are provided, and the four grooves 201 are evenly spaced and arranged around the groove 200. When a curved structure is adopted, such as Figure 5 and Figure 6 , three grooves 201 are provided, and the three grooves 201 are evenly spaced and arranged around the groove 200. The curved grooves 201 in this embodiment are in a fan-shaped structure.

[0034] In addition, if Figure 7 and Figure 8 The groove 201 may also be a plurality of annular grooves surrounding the groove 200. In this embodiment, two annular grooves 201 having a common center with the groove 200 are used.

[0035] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A gas discharge tube capable of generating a distorted electric field, characterized in that: It comprises an insulating tube body and end electrodes sealed at both ends of the insulating tube body, wherein a discharge gap is formed in the insulating tube body and located between the two end electrodes; the end electrode comprises an electron emission surface which is located on one side of the insulating tube body and coated with an electron emission coating; a groove and a plurality of grooves are arranged on the electron emission surface, wherein the groove is located at the center of the electron emission surface, and the plurality of grooves extend outward from the groove.

2. The gas discharge tube capable of generating a distorted electric field according to claim 1, characterized in that: The insulating tube body is a metallized ceramic tube.

3. The gas discharge tube capable of generating a distorted electric field according to claim 1, characterized in that: A graphite electrode for assisting in triggering gas ionization is arranged on the inner wall of the insulating tube.

4. The gas discharge tube capable of generating a distorted electric field according to claim 1, characterized in that: A plurality of grooves are evenly spaced around the groove.

5. The gas discharge tube capable of generating a distorted electric field according to claim 1, characterized in that: One end of the groove is communicated with the recess, and the other end of the groove extends outward from the recess.

6. The gas discharge tube capable of generating a distorted electric field according to claim 5, characterized in that: The groove is in a straight line structure or a curved line structure.

7. The gas discharge tube capable of generating a distorted electric field according to claim 6, characterized in that: The number of the grooves is three or four.

8. The gas discharge tube capable of generating a distorted electric field according to claim 1, characterized in that: The groove includes a plurality of annular grooves arranged around the groove.

9. The gas discharge tube capable of generating a distorted electric field according to claim 8, characterized in that: The grooves have two grooves.

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