Gas steepener switch with ultraviolet pre-ionization structure

Abstract

The application belongs to a kind of pulse power devices, and particularly relates to a gas steepening switch with ultraviolet pre-ionization structure, which solves the problems of high jitter, high inductance, short service life and poor reliability of existing steepening switches, and is difficult to meet the technical problems required by fast pulse trigger source.The gas steepening switch with ultraviolet pre-ionization structure comprises an upper electrode assembly, a lower electrode assembly, a gas nozzle, a switch housing, a first annular pre-ionization electrode and a second annular pre-ionization electrode arranged in the switch housing; the upper electrode assembly and the lower electrode assembly are oppositely arranged at two ends of the switch housing, and the upper electrode assembly and the lower electrode assembly form a closed cavity with the switch housing; the upper electrode assembly comprises an upper electrode, and the lower electrode assembly comprises a lower electrode; the upper electrode and the lower electrode are coaxially arranged, and the upper electrode and the lower electrode form a main gap; the first annular pre-ionization electrode and the second annular pre-ionization electrode are coaxially and oppositely arranged, and a pre-ionization gap is formed between the first annular pre-ionization electrode and the second annular pre-ionization electrode.

Description

Technical Field

[0001] This invention pertains to a pulsed power device, specifically a gas steepening switch with an ultraviolet pre-ionization structure. Background Technology

[0002] In pulsed power systems, the fast pulse trigger source generates electrical pulses to trigger the gas switches in the primary energy storage system. To ensure stable, precise, and controlled conduction of the gas switches, the electrical pulses generated by the fast pulse trigger source must possess characteristics of fast leading-edge speed, high amplitude, and low jitter. Simultaneously, the fast pulse trigger source itself must also exhibit high reliability and long lifespan. The pulse transformer type trigger source is a mature and reliable fast pulse trigger source. It first boosts the electrical pulse generated by the discharge in the primary circuit through a pulse transformer to achieve a high amplitude, and then compresses the leading edge of the electrical pulse through a gas steepening switch to achieve a fast leading-edge speed. In the pulse transformer type trigger source, the breakdown characteristics of the gas steepening switch have a decisive impact on the overall output performance of the trigger source, requiring the gas steepening switch to possess characteristics of low jitter, low inductance, high reliability, and long lifespan.

[0003] In their paper "Stiffening of the Output Pulse of a 100kV Trigger" (High Voltage Engineering, June 2008, Vol. 34, No. 6, pp. 1255-1260), Li Dengyun et al. introduced a two-gap steepening switch, which consists of a switch housing, a spherical electrode, and a conical electrode. This switch can compress the leading edge of a 90kV electrical pulse from 20ns to 2.3ns. In their paper "Development of a Trigger Source for a Triggered Vacuum Switch with a Steepening Gap" (High Power Laser and Particle Beams, January 2016, Vol. 28, No. 1, 015020-1-7), Mao Xinguo et al. introduced a trigger tube-type steepening switch, which consists of a trigger electrode, an insulating ceramic tube, a main electrode, and a ceramic tube housing. This switch can also effectively steepen the leading edge of electrical pulses. It can be seen that both types of steepening switches can effectively steepen the leading edge of the pulse; however, they have the following shortcomings: Firstly, due to the limitations of their own electrode structure and the lack of any measures to reduce jitter, the jitter of the two types of steepening switches is difficult to control at a low level, resulting in large jitter of the fast pulse trigger source and unstable output amplitude. Secondly, the two types of steepening switches are difficult to form multiple discharge channels during the discharge process, resulting in high inductance of the switch itself. This is not conducive to the fast pulse trigger source generating an electric pulse with a faster leading edge, and it also causes severe ablation of the steepening switch electrodes, which is not conducive to the long-term operation of the steepening switch.

[0004] In their paper "Design of a 3MV Autotransformer Ultraviolet Pre-ionization Switch" (High Power Laser & Particle Beams, August 2009, Vol. 21, No. 8, pp. 1255-1258), Li Junna et al. introduced an autotransformer ultraviolet pre-ionization peaking switch, which functions similarly to a steepening switch, both used to steepen the leading edge of an electrical pulse. This autotransformer ultraviolet pre-ionization peaking switch consists of a main gap, a pre-ionization gap, a supporting insulator, a nylon tie rod, and a voltage divider resistor; the pre-ionization gap is composed of a trigger disk, a tungsten needle, a stainless steel tip, and a ceramic insulator. When an electrical pulse is applied to the peaking switch, the pre-ionization gap can achieve a voltage difference through the voltage divider resistor installed outside the peaking switch housing; this causes the pre-ionization gap to break down first and generate pre-ionization, after which the main gap of the peaking switch breaks down under the ultraviolet radiation generated by the pre-ionization. The addition of an autotransformer-type UV pre-ionization structure to this peaking switch can significantly reduce switch bounce; however, it still has the following drawbacks: First, the autotransformer-type UV pre-ionization structure is relatively complex. On one hand, multiple voltage divider resistors need to be installed on the outside of the peaking switch housing; on the other hand, a ceramic insulator is installed between the tungsten needle and the trigger plate for potential isolation, and the stainless steel tip is welded to the trigger plate. This complex structure increases the failure rate of the peaking switch. Second, the autotransformer-type UV pre-ionization structure requires voltage divider resistors to be installed on the surface of the peaking switch housing, and the surface of the voltage divider resistors is in contact with the surface of the peaking switch housing. This increases the probability of surface flashover along the surface of the peaking switch housing or resistors, affecting the stable operation and lifespan of the peaking switch. Third, the pre-ionization electrode in this autotransformer-type UV pre-ionization structure is needle-shaped, which will cause severe electrode erosion after repeated discharges, thus adversely affecting the pre-ionization switch's performance.

[0005] In summary, existing steepening switches suffer from high jitter, high inductance, short lifespan, and poor reliability, making it difficult to meet the requirements of fast pulse triggering sources. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problems of existing steepening switches, such as high jitter, high inductance, short life and poor reliability, which make it difficult to meet the requirements of fast pulse triggering sources. The invention provides a gas steepening switch with an ultraviolet pre-ionization structure for use in fast pulse triggering sources.

[0007] The technical concept of this invention is:

[0008] This invention adds two ultraviolet pre-ionization electrodes to the traditional two-gap steepening switch consisting of an upper electrode and a lower electrode. The upper electrode and the first annular pre-ionization electrode, the first annular pre-ionization electrode and the second annular pre-ionization electrode, and the second annular pre-ionization electrode and the lower electrode respectively form three structural capacitors. When an externally applied electrical pulse is applied to the upper electrode, a potential difference is generated across the pre-ionization gap formed by the first and second annular pre-ionization electrodes through voltage division by the three structural capacitors. Under the influence of this potential difference, the pre-ionization gap breaks down first and generates pre-ionization. Subsequently, the main gap formed by the upper and lower electrodes is broken down by ultraviolet light irradiation generated by the pre-ionization breakdown.

[0009] To solve the above-mentioned technical problems and realize the above-mentioned inventive concept, the technical solution adopted by the present invention is as follows:

[0010] A gas steepening switch with an ultraviolet pre-ionization structure is characterized by comprising an upper electrode assembly, a lower electrode assembly, a gas nozzle, a switch housing, a first annular pre-ionization electrode disposed inside the switch housing, and a second annular pre-ionization electrode.

[0011] The upper electrode assembly and the lower electrode assembly are disposed opposite to each other at both ends of the switch housing, and the upper electrode assembly and the lower electrode assembly together with the switch housing form a closed cavity; the upper electrode assembly includes an upper electrode, and the lower electrode assembly includes a lower electrode; the upper electrode and the lower electrode are coaxially disposed, and the upper electrode and the lower electrode form a main gap;

[0012] The air nozzle is located on the front outer wall of the switch housing. The air nozzle is used to release or fill the gas steepening switch.

[0013] The first annular pre-ionization electrode and the second annular pre-ionization electrode are coaxially disposed opposite each other on the inner wall of the switch housing, and a pre-ionization gap is formed between the first annular pre-ionization electrode and the second annular pre-ionization electrode.

[0014] Furthermore, the upper electrode assembly also includes an upper electrode base, and the upper electrode is disposed on the upper end of the switch housing via the upper electrode base;

[0015] The lower electrode assembly also includes a lower electrode base, through which the lower electrode is disposed at the lower end of the switch housing;

[0016] The lower electrode is a hollow cylindrical electrode, comprising a hollow body and a body base arranged coaxially; the lower port of the hollow body is connected to the body base;

[0017] The inner diameter of the upper port of the hollow body is larger than that of the lower port, and the upper port has a wedge-shaped structure;

[0018] The main body base and the lower electrode base are coaxially connected.

[0019] Furthermore, the hollow body is provided with multiple grooves along its circumference, and metal wedge-shaped blocks are embedded in the grooves.

[0020] Furthermore, an annular protrusion is provided on the inner wall of the switch housing;

[0021] The first annular pre-ionization electrode is mounted on the top of the annular protrusion, with the opening of the first annular pre-ionization electrode facing downwards;

[0022] The second annular pre-ionization electrode is installed at the bottom of the annular protrusion, with the opening of the second annular pre-ionization electrode facing upwards.

[0023] Furthermore, both the upper and lower electrodes are made of copper-impregnated graphite.

[0024] The work function of the metal wedge is greater than or equal to 2.5 times that of the copper-doped graphite.

[0025] Furthermore, the first annular pre-ionization electrode includes a first annular base and a first annular blade connected vertically; one end of the first annular base is sleeved on the top of the annular protrusion;

[0026] The second annular pre-ionization electrode includes a vertically connected second annular base and a second annular blade.

[0027] One end of the second annular base is fitted onto the bottom of the annular protrusion;

[0028] The first annular cutting edge and the second annular cutting edge are coaxially opposite each other.

[0029] Furthermore, the wedge angle between the upper port of the hollow body and the metal wedge block is 8 to 12 degrees, and the radius R of the rounded corner at the wedge end is 0.1 to 0.3 mm.

[0030] The compressive strength of copper-impregnated graphite is greater than 2000 kg / cm². 2 The average density is greater than 3 g / cm³. 3 .

[0031] Furthermore, the distance between the central axis of the upper electrode and / or the lower electrode and the outer surface of the first and second annular cutting edges is 14-16 mm.

[0032] The distance between the outer wall of the first annular pre-ionization electrode near the upper electrode and the lower end face of the upper electrode, and the distance between the outer wall of the second annular pre-ionization electrode near the lower electrode and the upper port of the lower electrode, are both 4 to 6 mm.

[0033] The distance between the end of the annular protrusion furthest from the switch housing and the inner surface of the first and second annular blades is 2.5 to 3 mm.

[0034] The distance between the first and second annular cutting edges is 1 to 1.5 mm; and the angle between the sharp edges of the first and second annular cutting edges is 8 to 12 degrees, with a cutting edge height of 2 to 4 mm.

[0035] Furthermore, the switch housing is an insulator;

[0036] Both the upper electrode base and the lower electrode base are disc-shaped and made of stainless steel.

[0037] The materials for both the first annular pre-ionization electrode and the second annular pre-ionization electrode are thorium-tungsten alloy or high-entropy alloy;

[0038] The air nozzle is made of PEEK.

[0039] The sealed cavity is filled with a mixture of sulfur hexafluoride and argon, with argon accounting for more than 30% of the gas volume.

[0040] Furthermore, the hollow body and the body base are integrally formed;

[0041] The first annular base and the first annular cutting edge are made as a single unit;

[0042] The second annular base and the second annular blade are made as a single unit.

[0043] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0044] (1) In the gas steepening switch with ultraviolet pre-ionization structure of the present invention, the upper electrode and the first annular pre-ionization electrode, the first annular pre-ionization electrode and the second annular pre-ionization electrode, and the second annular pre-ionization electrode and the lower electrode form three structural capacitors. The three structural capacitors have a voltage division effect, which can generate a potential difference on the pre-ionization gap formed by the first annular pre-ionization electrode and the second annular pre-ionization electrode. Under the action of this potential difference, the pre-ionization gap breaks down first and generates pre-ionization and ultraviolet light, which can irradiate the main gap formed by the upper electrode and the lower electrode more efficiently, and reduce the breakdown jitter of the gas steepening switch of the present invention.

[0045] (2) The gas steepening switch with ultraviolet pre-ionization structure of the present invention has a simple structure. It can generate ultraviolet pre-ionization by utilizing the three structural capacitors formed by the upper electrode and the first ring pre-ionization electrode, the first ring pre-ionization electrode and the second ring pre-ionization electrode, and the second ring pre-ionization electrode and the lower electrode to divide the voltage. This avoids the use of additional electronic components and improves the reliability of the gas steepening switch of the present invention.

[0046] (3) In the gas steepening switch with ultraviolet pre-ionization structure of the present invention, both the upper and lower electrodes are made of high-performance copper-infiltrated graphite. This material makes the upper and lower electrodes highly stable in terms of breakdown and resistant to ablation. In addition, the first and second annular pre-ionization electrodes are also made of ablation-resistant metal materials (i.e., thorium-tungsten alloy or high-entropy alloy), which makes the entire gas steepening switch of the present invention have a long life and high stability.

[0047] (4) In the gas steepening switch with ultraviolet pre-ionization structure of the present invention, the upper electrode and the lower electrode are made of copper-impregnated graphite material, and the wedge block to be embedded is made of metal material. The work function of the metal material is 2.5 times higher than that of the copper-impregnated graphite, which can make the gas steepening switch generate a discharge channel only at the copper-impregnated graphite. Therefore, a stable number of discharge channels can be generated, which is beneficial to reduce the inductance of the gas steepening switch.

[0048] (5) The closed cavity of the gas steepening switch with ultraviolet pre-ionization structure of the present invention is filled with a mixture of sulfur hexafluoride and argon gas. This mixture is more conducive to generating multi-channel discharge, which helps to further reduce the inductance and electrode erosion of the gas steepening switch. Attached Figure Description

[0049] Figure 1 This is a cross-sectional view of an embodiment of the gas steepening switch with ultraviolet pre-ionization structure of the present invention.

[0050] Figure 2 This is a schematic diagram of the lower electrode structure in an embodiment of the gas steepening switch with ultraviolet pre-ionization structure of the present invention.

[0051] Figure 3 This is a schematic diagram of the second annular pre-ionization electrode structure in an embodiment of the gas steepening switch with ultraviolet pre-ionization structure of the present invention.

[0052] The attached figures are labeled as follows:

[0053] 1-Switch housing, 2-Upper electrode, 201-Upper electrode base; 3-Lower electrode, 301-Lower electrode base, 302-Hollow body, 303-Body base, 304-Groove, 305-Upper port, 306-Lower port; 4-First annular pre-ionization electrode, 401-First annular base, 402-First annular blade; 5-Second annular pre-ionization electrode, 501-Second annular base, 502-Second annular blade; 6-Nozzle, 7-Annular protrusion, 8-Closed cavity. Detailed Implementation

[0054] like Figure 1 As shown, the present invention discloses a gas steepening switch with an ultraviolet pre-ionization structure, comprising a switch housing 1, an upper electrode assembly, a lower electrode assembly, a first annular pre-ionization electrode 4, a second annular pre-ionization electrode 5, and a gas nozzle 6.

[0055] The switch housing 1 is a cylindrical hollow shell with a height of 55mm, an inner diameter of 45mm, and an outer diameter of 80mm, made of plexiglass. Two sets of six M5 threaded holes are provided on each side wall of the switch housing 1 for connection to the upper and lower electrode assemblies. An annular protrusion 7 is provided on the inner wall of the switch housing 1, with six M2 threaded holes on both its upper and lower surfaces for fixing the first annular pre-ionization electrode 4 and the second annular pre-ionization electrode 5. Annular steps, 5mm high and 3mm thick, are provided on the front and rear outer walls of the switch housing 1 to prevent discharge along the side walls. The switch housing 1, together with the upper and lower electrode assemblies, forms a closed cavity 8 using screws and sealing rings. An M6 threaded through hole is provided on the front outer wall of the switch housing 1 for installing an air nozzle 6.

[0056] The upper electrode assembly consists of an upper electrode 2 and an upper electrode base 201. The upper electrode base 201 is disc-shaped, made of stainless steel, with a diameter of 73 mm and a thickness of 4 mm. The upper electrode base 201 has six circular through holes with a diameter of 6 mm along its circumference, and a central M26 threaded hole with a depth of 2.5 mm. The upper electrode 2 is cylindrical, with a diameter of 26 mm and a height of 20 mm, and is made of high-performance copper-infiltrated graphite. The upper edge of the cylinder has an M26 thread, and the lower edge has a radius of radius R3. The upper electrode base 201 and the upper electrode 2 are connected as a single unit via threads.

[0057] The lower electrode assembly consists of a lower electrode base 301, a hollow body 302, and a body base 303. The lower electrode base 301 is disc-shaped and made of stainless steel; its structure and dimensions are identical to those of the upper electrode base 201. The body base 303 is made of high-performance copper-infiltrated graphite; for example... Figure 2 As shown, the hollow body 302 is a hollow ring with an inner diameter of 12mm, an outer diameter of 15mm, and a height of 10mm. The upper port 305 of the hollow body 302 is wedge-shaped with a wedge angle of 9.5 degrees and a rounded tip with a radius of R0.2mm. Four grooves 304 with a depth of 8mm are evenly spaced along the circumference of the hollow body 302, and a wedge block to be embedded is set in each groove 304. The material of the wedge block to be embedded is a wedge-shaped tungsten block, and the lower end of the wedge-shaped tungsten block is adapted to the body base 303. The body base 303 is disc-shaped with a diameter of 26mm and a thickness of 7.5mm. An M26 screw hole is provided on the lower surface, and it is connected to the lower electrode base 301 as a whole.

[0058] like Figure 3As shown, the first annular pre-ionization electrode 4 and the second annular pre-ionization electrode 5 have the same structure. The first annular pre-ionization electrode 4 consists of a first annular base 401 and a first annular blade 402, and the second annular pre-ionization electrode 5 consists of a second annular base 501 and a second annular blade 502. Both the first annular base 401 and the second annular base 501 are annular structures with an inner diameter of 40mm, an outer diameter of 45mm, and a thickness of 1mm. Six through holes with a diameter of 3mm are set at equal angles on the base for mounting the first annular pre-ionization electrode 4 and the second annular pre-ionization electrode 5 onto the annular protrusion 7 on the inner wall of the switch housing 1. The first annular blade 402 and the second annular blade 502 are upright annular blades with a blade height of 3mm and a blade tip angle of 10 degrees. The distance between the first annular blade 402 and the second annular blade 502 is 1.2mm. The distance between the end of the annular protrusion 7 furthest from the switch housing 1 and the inner surfaces of the first annular blade 402 and the second annular blade 502 is 2.6 mm. The connections between the first annular base 401 and the first annular blade 402, and between the second annular base 501 and the second annular blade 502, are rounded, with both the inner and outer corner radii being R0.5 mm. The first annular pre-ionization electrode 4 and the second annular pre-ionization electrode 5 are made of a high-entropy alloy, which has excellent ablation resistance.

[0059] To ensure that the ultraviolet light generated by the discharge of the pre-ionization gap formed by the first annular pre-ionization electrode 4 and the second annular pre-ionization electrode 5 can irradiate the main gap formed by the upper electrode 2 and the lower electrode 3 to the maximum extent, the distance between the central axis of the upper electrode 2 or the lower electrode 3 and the outer surface of the first annular blade 402 or the outer surface of the second annular blade 502 is 15 mm; the distance between the outer wall of the first annular pre-ionization electrode 4 near the upper electrode 2 and the lower end face of the upper electrode 2, and the distance between the outer wall of the second annular pre-ionization electrode 5 near the lower electrode 3 and the upper port 305 of the lower electrode 3 are both 5 mm.

[0060] In this embodiment, the gas nozzle 6 is installed on the outer wall of the front end of the switch housing 1 to charge or de-charge the gas steepening switch cavity. The gas nozzle 6 is made of PEEK. The gas steepening switch cavity is filled with a mixture of sulfur hexafluoride and argon, with argon accounting for 35%, which is beneficial for forming multi-channel discharge. The gas steepening switch of this invention can generate ultraviolet pre-ionization through its own structural capacitance voltage division, and can generate four discharge channels during discharge. It features low jitter, low inductance, resistance to electrode ablation, simple structure, and long lifespan.

[0061] The working principle or process of the above embodiments is as follows:

[0062] When an external pulse voltage is applied to the upper electrode 2 of the gas steepening switch, a potential difference is generated across the pre-ionization gap formed by the three structural capacitors—the upper electrode 2 and the first annular pre-ionization electrode 4, the first annular pre-ionization electrode 4 and the second annular pre-ionization electrode 5, and the second annular pre-ionization electrode 5 and the lower electrode 3—due to the voltage division effect between these three capacitors. Under this potential difference, the pre-ionization gap breaks down first, generating pre-ionization and ultraviolet light. Subsequently, the main gap formed by the upper electrode 2 and the lower electrode 3 breaks down under the irradiation of the ultraviolet light generated by the pre-ionization breakdown, thus completing the conduction of the entire gas steepening switch.

Claims

1. A gas steepening switch with an ultraviolet pre-ionization structure, characterized in that: It includes an upper electrode assembly, a lower electrode assembly, an air nozzle (6), a switch housing (1), a first annular pre-ionization electrode (4) and a second annular pre-ionization electrode (5) disposed inside the switch housing (1); an annular protrusion (7) is provided on the inner wall of the switch housing (1); The upper electrode assembly and the lower electrode assembly are disposed opposite to each other at both ends of the switch housing (1), and the upper electrode assembly and the lower electrode assembly together with the switch housing (1) form a closed cavity (8); the upper electrode assembly includes an upper electrode (2) and an upper electrode base (201), the upper electrode (2) being disposed at the upper end of the switch housing (1) via the upper electrode base (201); the lower electrode assembly includes a lower electrode (3) and a lower electrode base (301), the lower electrode (3) being disposed at the lower end of the switch housing (1) via the lower electrode base (301); the upper electrode assembly includes an upper electrode (2) and an lower electrode base (301), the lower electrode (3) being disposed at the lower end of the switch housing (1) via the lower electrode base (301); the upper electrode assembly includes an upper electrode (2) and an lower electrode base (301), the upper electrode assembly and the lower electrode base (301) forming a closed cavity (8 ... The upper electrode (2) and the lower electrode (3) are coaxially arranged, and the upper electrode (2) and the lower electrode (3) form a main gap; the lower electrode (3) is a hollow cylindrical electrode, including a hollow body (302) and a body base (303) arranged coaxially; the lower port (306) of the hollow body (302) is connected to the body base (303); the inner diameter of the upper port (305) of the hollow body (302) is larger than the inner diameter of the lower port (306), and the upper port (305) is a wedge-shaped structure; the body base (303) is coaxially connected to the lower electrode base (301); The air nozzle (6) is disposed on the front outer wall of the switch housing (1), and the air nozzle (6) is used to release or fill the gas steepening switch. The first annular pre-ionization electrode (4) and the second annular pre-ionization electrode (5) are coaxially opposite to each other on the inner wall of the switch housing (1), and a pre-ionization gap is formed between the first annular pre-ionization electrode (4) and the second annular pre-ionization electrode (5); the first annular pre-ionization electrode (4) includes a first annular base (401) and a first annular blade (402) connected vertically; one end of the first annular base (401) is sleeved on the top of the annular protrusion (7); the second annular pre-ionization electrode (5) includes a second annular base (501) and a second annular blade (502) connected vertically; one end of the second annular base (501) is sleeved on the bottom of the annular protrusion (7); the first annular blade (402) and the second annular blade (502) are coaxially opposite to each other.

2. The gas steepening switch with ultraviolet pre-ionization structure according to claim 1, characterized in that: The hollow body (302) has a plurality of grooves (304) arranged along the circumference, and metal wedges are embedded in the grooves (304).

3. A gas steepening switch with an ultraviolet pre-ionization structure according to claim 2, characterized in that: The first annular pre-ionization electrode (4) is mounted on the top of the annular protrusion (7), and the opening of the first annular pre-ionization electrode (4) faces downward; The second annular pre-ionization electrode (5) is installed at the bottom of the annular protrusion (7), and the opening of the second annular pre-ionization electrode (5) faces upward.

4. A gas steepening switch with an ultraviolet pre-ionization structure according to claim 3, characterized in that: The upper electrode (2) and the lower electrode (3) are both made of copper-impregnated graphite; The work function of the metal wedge block is greater than or equal to 2.5 times that of the copper-infiltrated graphite.

5. A gas steepening switch with an ultraviolet pre-ionization structure according to claim 4, characterized in that: The upper port (305) of the hollow body (302) and the wedge angle of the metal wedge block are both 8 to 12 degrees, and the radius R of the rounded corner at the end of the wedge is 0.1 to 0.3 mm. The compressive strength of the copper-impregnated graphite is greater than 2000 kg / cm². 2 The average density is greater than 3 g / cm³ 3 .

6. A gas steepening switch with an ultraviolet pre-ionization structure according to claim 5, characterized in that: The distance between the central axis of the upper electrode (2) and / or the lower electrode (3) and the outer surface of the first annular blade (402) and the outer surface of the second annular blade (502) is 14 to 16 mm. The distance between the outer wall of the first annular pre-ionization electrode (4) near the upper electrode (2) and the lower end face of the upper electrode (2) is 4-6 mm, and the distance between the outer wall of the second annular pre-ionization electrode (5) near the lower electrode (3) and the upper port (305) of the lower electrode (3) is 4-6 mm. The distance between the end of the annular protrusion (7) away from the switch housing (1) and the inner surface of the first annular blade (402) and the inner surface of the second annular blade (502) is 2.5 to 3 mm. The distance between the first annular cutting edge (402) and the second annular cutting edge (502) is 1 to 1.5 mm; and the angle of the tip of the first annular cutting edge (402) and the second annular cutting edge (502) is 8 to 12 degrees, and the cutting edge height is 2 to 4 mm.

7. A gas steepening switch with an ultraviolet pre-ionization structure according to claim 6, characterized in that: The switch housing (1) is an insulator; Both the upper electrode base (201) and the lower electrode base (301) are disc structures and are made of stainless steel. The first annular pre-ionization electrode (4) and the second annular pre-ionization electrode (5) are both made of thorium-tungsten alloy or high-entropy alloy; The material of the air nozzle (6) is PEEK; The enclosed cavity (8) is filled with a mixture of sulfur hexafluoride and argon, and the volume ratio of argon is greater than or equal to 30%.

8. A gas steepening switch with an ultraviolet pre-ionization structure according to claim 7, characterized in that: The hollow body (302) and the body base (303) are integrally formed; The first annular base (401) and the first annular blade (402) are integrally formed; The second annular base (501) and the second annular blade (502) are integrally formed.

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