CN105555003A - Method and device for reducing arc plasmatron electrode ablation - Google Patents

Abstract

The invention relates to a method and a device for reducing electrode ablation of an arc plasma generator. The arc plasma generator device mainly includes a cathode, an anode, an insulating part and an outer casing. Through mechanical knurling, wire drawing, sandblasting, shot peening and other treatments on the electrode surface of the arc plasma generator, the surface morphology, stress state, microstructure and crystal phase structure of the electrode are changed, thereby changing the energy state of the electrode surface and affecting The attachment reaction of the arc attached to the electrode surface can disperse and miniaturize the attachment points, thereby reducing the electrode ablation of the arc plasma generator.

Description

A method and device for reducing arc plasma generator electrode ablation

technical field

The invention relates to a method and a device for reducing electrode ablation of an arc plasma generator.

Background technique

DC non-transferred arc plasma generators have decades of application and research history in a wide range of fields such as industrial manufacturing, scientific exploration, environmental protection, medical care, and national defense. The forms of generators are even more diverse, from the most commonly used structure with only cylindrical cathode and tubular anode, tube arc, laminated type, to a wide variety of special structures. Regardless of the structure, use and power level of the non-transferred arc, the common feature is that the gas discharge arc is used as the current channel to connect the cathode and the anode. In the flowing argon, nitrogen, hydrogen, air and other gases or mixed gases, a discharge arc is generated between the cathode and the anode and the working gas is heated to form a hot plasma jet of thousands or even tens of thousands of degrees.

The current density of the arc in the electrode surface attachment area may exceed 10 ⁸ A/m ² , and the life of the generator caused by electrode ablation has always affected the efficient use of this type of generator, reducing maintenance costs and technical requirements, and promoting it to a wider range. The bottleneck factor of long-term continuous running applications. At the same time, the contamination of electrode ablation products also limits the application of this type of plasma in the synthesis of fine component materials and the accurate evaluation of material thermal properties in wind tunnel experiments. Therefore, various attempts to reduce electrode ablation to improve plasma generator lifetime have been carried out for decades.

High-efficiency and continuous operation of high-power arc plasma generators in industrial applications requires generators with long life and low ablation. At present, a longer intermediate section is inserted between the cathode and the anode in the generator, and the distance between the cathode and the anode is increased to increase the arc voltage, so that the arc current can be reduced under the same arc power condition to reduce electrode ablation . Or use multiple pairs of electrode groups at the same time to disperse the attachment of the arc on the electrode surface, so as to reduce the local current density of the attached arc root and slow down the local malignant ablation of the electrode. It's just that the structure of the thermal plasma generator with this structure is complicated, the maintenance cost is large, and the power supply needs a high-voltage design.

Contents of the invention

The object of the present invention is to propose a method and device for reducing the anode ablation of the DC non-transferred arc plasma generator.

The purpose of the present invention is achieved like this:

The invention provides a method for reducing electrode ablation of an arc plasma generator,

The first step is to perform surface treatment on the anode of the arc plasma generator, which is used to affect the attachment reaction energy of the arc attached to the electrode surface or disperse the miniaturized attachment points, thereby reducing electrode ablation;

In the second step, the external voltage excites an arc between the cathode and the anode, and the arc is transmitted along the direction from the cathode to the anode;

In the third step, the arc is attached to the surface-treated anode, and the anode is weakened by the arc.

Preferably, the anode surface treatment is mechanical knurling treatment, wire drawing treatment, sand blasting treatment or shot peening treatment.

Utilize above-mentioned method the present invention also provides a kind of arc plasma generator that reduces electrode ablation to comprise:

cathode;

an anode, arranged downstream of the cathode arc transmission direction, and the anode is surface-treated so that the anode has a specific surface structure;

Preferably, it also includes:

an intermediate section disposed between the cathode and the anode;

an insulator, the two ends of the insulator are respectively connected to the middle section and the anode;

an outer sleeve wrapping the middle section, the insulating member and the anode connection assembly.

Preferably, it also includes a gas path and a water cooling path,

The gas path is arranged between the cathode and the middle section and between the middle section and the anode to provide working gas for the generator;

The water-cooling channel is arranged in the space between the middle section, the anode and the insulator assembly and the outer sleeve, and is used for cooling the anode, the cathode and the middle section.

Preferably, the anode surface treatment is mechanical knurling treatment, wire drawing treatment, sand blasting treatment or shot peening treatment.

Preferably, the mechanical knurling treatment and wire drawing treatment change the surface morphology and stress state of the anode; the sand blasting treatment and shot peening treatment change the microstructure and crystal orientation structure of the anode surface.

Preferably, the thickness of the anode surface mechanically treated is on the order of 1 mm, and the edges of the convex points on the anode surface after treatment are smooth without sharp points.

Beneficial effects of the present invention:

First of all, according to the type and flow rate of the actual gas used and the working conditions, the surface of the generator electrode can be treated by mechanical knurling, wire drawing, sandblasting, shot peening and other methods. The operational stability and lifetime of the arc plasma generator are improved.

Description of drawings

Fig. 1 is the schematic diagram of arc plasma generator through the treatment of electrode surface;

Figure 2 is an enlarged view of area A in Figure 1 .

detailed description

The basic idea of the present invention is to carry out mechanical knurling, wire drawing, sandblasting, shot blasting and other treatments on the electrode surface of the arc plasma generator to change the electrode surface morphology, stress state, microstructure and crystal phase structure, thereby changing the electrode surface. The energy condition of the arc will affect the attachment reaction energy of the arc attached to the electrode surface or disperse and micronize the attachment points, thereby reducing electrode ablation and improving the operation stability and life of the arc plasma generator.

FIG. 1 shows an arc plasma generator for reducing electrode ablation, a cathode 1 , an intermediate section 2 , an anode 3 , an insulating member 4 and an outer sleeve 5 . The middle section 2 is arranged downstream of the arc transmission direction of the cathode 1; the anode 3 is surface-treated to make the anode 3 have a specific surface structure; the two ends of the insulator 4 are respectively connected to the middle section 2 and the anode 3; the outer sleeve 5 wraps the middle section 2 and the insulator 4 Connect the assembly with the anode 3. The generator also includes a gas path 8 and a water cooling path 9 .

The gas path 8 is set between the cathode 1 and the middle section 2 and between the middle section 2 and the anode 3 to provide working gas for the generator; the water cooling passage 9 is set in the combination of the middle section 2, the anode 3 and the insulator 4 The space between the casing and the outer casing is used for cooling the anode 3 , cathode 1 and the middle section 2 . The hot plasma jet 6 and the diffused arc root 7 are also shown in the figure.

If the generator does not include an intermediate section, the gas path 8 is only provided between the cathode 1 and the anode 3 . The water cooling passage 9 is used for cooling the anode 3 and the cathode 1 .

The external voltage excites the plasma to generate an arc between the cathode 1 and the anode 3; the arc starts from the cathode 1 and moves towards the anode 3 through the middle section 2 and the insulator 4, and finally the arc root 7 is attached to the anode 1. The anode 1 undergoes surface treatment to change the electrode surface morphology, stress state, microstructure and crystal phase structure, thereby changing the energy state of the electrode surface, affecting the attachment reaction energy of the arc attached to the electrode surface or dispersing and micro-attaching points, Thereby reducing electrode ablation.

As shown in Figure 2, after shot peening treatment on the surface of the anode, the surface of the anode has a fine structure. Shot peening changes the surface morphology, stress state, microstructure and crystal phase structure of the anode. At this time, the thickness of the mechanical treatment on the surface of the anode is on the order of 1 mm, and the edges of the convex points on the surface of the anode after treatment are smooth without sharp points.

The anode surface can also be treated by mechanical knurling, wire drawing, sandblasting and other methods, which can also change the energy status of the anode surface, affect the attachment reaction energy of the arc attached to the anode surface or disperse and micronize the attachment point, and reduce the The effect of the arc on the ablation of the anode. Mechanical knurling treatment and wire drawing treatment change the surface morphology and stress state of the anode; sand blasting treatment and shot peening treatment change the microstructure and crystal orientation structure of the anode surface.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. A method for reducing arc plasma generator electrode ablation, is characterized in that, comprises the steps: The first step is to perform surface treatment on the anode of the arc plasma generator, which is used to affect the attachment reaction energy of the arc attached to the electrode surface or disperse the miniaturized attachment points, thereby reducing electrode ablation; In the second step, the external voltage excites an arc between the cathode and the anode, and the arc is transmitted along the direction from the cathode to the anode; In the third step, the arc is attached to the surface-treated anode, and the anode is weakened by the arc. 2. The method for reducing arc plasma generator electrode ablation according to claim 1, wherein the anode surface treatment is mechanical knurling treatment, wire drawing treatment, sandblasting treatment or shot peening treatment. 3. An arc plasma generator that reduces electrode ablation, is characterized in that, comprising: cathode; The anode is arranged downstream of the arc transmission direction of the cathode, and the anode has a specific surface structure through surface treatment. 4. The arc plasma generator according to claim 3, further comprising: an intermediate section disposed between the cathode and the anode; an insulator, the two ends of the insulator are respectively connected to the middle section and the anode; an outer sleeve wrapping the middle section, the insulating member and the anode connection assembly. 5. The arc plasma generator according to claim 4, further comprising a gas path and a water cooling path, The gas path is arranged between the cathode and the middle section and between the middle section and the anode to provide working gas for the generator; The water-cooling channel is arranged in the space between the middle section, the anode and the insulator assembly and the outer sleeve, and is used for cooling the anode, the cathode and the middle section. 6 . The arc plasma generator according to claim 3 , wherein the anode surface treatment is mechanical knurling treatment, wire drawing treatment, sand blasting treatment or shot peening treatment. 7. The arc plasma generator according to claim 6, characterized in that, the mechanical knurling treatment and wire drawing treatment change the surface morphology and stress condition of the anode; the sandblasting treatment and shot peening treatment change the microcosmic surface of the anode organization and crystallographic structure. 8. The arc plasma generator according to claim 3, characterized in that the thickness of the mechanical treatment on the anode surface is on the order of 1 millimeter, and the edges of the convex points on the anode surface after treatment are smooth without sharp points.