Composite cathode high-power plasma generator and arc striking method

Abstract

The invention discloses a composite cathode high-power plasma generator and an arc striking method, the composite cathode high-power plasma generator comprises a composite cathode, an arc striking electrode, an inter-electrode plug-in and an anode, the composite cathode is composed of an end face cathode and a ring target cathode, the end face cathode is located at the uppermost end and fixed by a cathode support cooling unit, and the ring target cathode is located at the lower end. Then, a ring target cathode, an arc striking electrode, a plurality of inter-electrode plug-ins and an anode are sequentially connected; the end face cathode, the cathode ring, the arc striking electrode, the inter-electrode plug-in and the outer ring of the anode are all fixed by independent insulating rings to form a modular structure and are coaxially and tightly connected in an insulating manner through circumferentially distributed pressing rods, an arc channel is formed among all the electrodes, and gas inlet rings capable of generating eddy gas are arranged among the rings; the cathode supporting and cooling unit is provided with an independent cooling channel used for cooling the end face cathode. According to the invention, a modular structural design is adopted, the installation is convenient and reliable, the power can reach hundreds of millions to several megawatts, the composite cathode effectively reduces cathode ablation, the discharge is stable, and the service life is long.

Description

technical field [0001] The invention belongs to the technical field of plasma generated by a direct current arc, and particularly relates to a composite cathode high-power plasma generator and an arc striking method. Background technique [0002] The high-temperature plasma generated by arc discharge is called arc plasma, which belongs to the category of thermal plasma. Thermal plasma has the characteristics of high temperature, high enthalpy, high energy density and controllable atmosphere, and can be widely used in machining, spraying, material Preparation, waste treatment, energy and other fields. Large-scale application in industry requires plasma generators with high stability, high power, high efficiency and long life. [0003] The DC arc plasma generator has the advantages of simple structure, high stability, high power, and high electrothermal conversion efficiency, which is more in line with the needs of industrial applications. Most of the existing main forms of ...

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Problems solved by technology

Most of the existing main forms of non-transferred arc plasma generators adopt high-frequency start-up mode, introduce a trigger electrode, form a discharge between the cathode and the trigger electrode, the discharge arc sprays to the anode, and ignites the arc between the cathode and the anode. The distance between the electrodes is small, and it is impossible to obtain higher power through a simple two-electrode structure. Therefore, there are two ways to increase the power of these plasma generators. One is to increase the discharge current, and the other is to increase the discharge voltage, but the discharge current If it is too large, the thermal efficiency will decrease and the electrode life will be shortened. Therefore, increasing the discharge voltage, that is, increasing the arc length is an effective way to increase power.

When the current remains constant, increasing the working gas flow can increase the arc length to increase the voltage, but the gas flow cannot be increased without limit. Excessive gas flow will directly affect the plasma heating efficiency and discharge stability. When the gas flow reaches a certain value , will blow out the arc, and the power increase is restricted by many factors, generally no more than 300 kilowatts

[0004] In order to improve the power of the plasma generator, the existing plasma generator is developing towards the direction of inter-electrode insertion section. It is composed of inert gas and water-cooled components. Due to the complex structure of the insertion section between electrodes and the need for electricity, ventilation and water cooling, how to solve the above-mentioned manufacturing and installation difficulties is still a problem that still exists in the industrialization prospect and needs to be solved urgently.

[0005] Existing arc plasma generators generally use water-cooled solid cathodes, the cathode arc spots are concentrated, the cathode is severely ablated, and the service life is short, or the tubular cathode is used, although the ablation area is increased, but the stability during the discharge process is poor

In addition, the water cooling system of the cathode and anode electrodes is not separated, which makes it difficult to disassemble and detect leaks, and the water cooling effect will be greatly reduced. When the power increases, these problems will become more prominent. The service life generally does not exceed 200 hours, which seriously restricts high-power plasmas. Industrial Application of Volume Generator

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