High-power cascade arc plasma generator

Abstract

The invention discloses a high-power cascade arc plasma generator, which belongs to the technical field of plasmas and structurally comprises a cathode structure, a cascade structure and an anode structure according to the plasma generation and injection direction. The cathode structure is composed of two cathode assemblies and a cathode seat, wherein the two cathode assemblies and the cathode seat are in a positioning type. The cascading structure is formed by stacking a plurality of cascading sheets and gaskets, and each cascading sheet is provided with a snakelike water cooling channel and an air inlet channel; the anode structure is composed of a step-shaped flange. According to the device, the air inlet channel and the snakelike cooling water channel are arranged in the cascade sheet, so that ablation of plasma to the discharge channel in the discharge process is reduced, and the discharge power reaches the MW level.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plasma, and particularly relates to a high-power cascade arc plasma generator. BACKGROUND

[0002] The high-power cascade arc plasma source is widely used in material synthesis (such as nano-powder and diamond film) and surface modification due to the advantages of high energy density and high ionization degree in waste treatment and other fields. The high-power cascade arc plasma source has a high discharge power, and a large amount of heat exchange occurs between the plasma and the electrode and the reactor wall, so that there is instability in arc root adhesion, imbalance in arc column contraction and expansion during the discharge process. SUMMARY

[0003] To make up for the deficiencies of the prior art, the application provides a high-power cascade arc plasma generator. The high-power cascade arc plasma generator integrates a serpentine water cooling channel and a distributed gas inlet channel through cascade sheets, realizes controllable expansion of an arc length, and enables discharge power to reach the MW level and remain stable.

[0004] The technical scheme of the application is as follows:

[0005] A high-power cascade arc plasma generator comprises, in sequence along a plasma generation and injection direction, a cathode structure, a cascade structure and an anode structure.

[0006] The cathode structure comprises two cathode assemblies at an included angle alpha and a cathode seat, the included angle alpha ranges from 0° to 120°, and the electrode ports of the two cathode assemblies are located on the same horizontal plane.

[0007] The cascade structure comprises n cascade sheets and gaskets stacked alternately, n is a positive integer ranging from 10 to 30, each cascade sheet is provided with a serpentine water cooling channel and at least one gas inlet channel.

[0008] The anode structure is a stepped flange, and the inner wall of the discharge channel is provided with a molybdenum ring protective layer.

[0009] In the above technical scheme, the cathode assembly comprises a conductive electrode, a metal sleeve and a ceramic tube arranged coaxially; the metal sleeve covers the conductive electrode, and the upper and lower ends of the metal sleeve are provided with cooling water interfaces, and the water flow direction is from bottom to top; the ceramic tube covers the metal sleeve, and the outer side of the ceramic tube is provided with an inlet / outlet gas channel.

[0010] In the above technical scheme, the discharge channel inner wall of the cathode seat is provided with a molybdenum ring protective layer, and the cathode assembly is fixed to the cathode seat by threads.

[0011] In the above technical scheme, the gas inlet path of the cathode structure is as follows: the gas is introduced into the gap between the conductive electrode and the metal sleeve, forms a vortex gas flow through the gas swirling ring, and is finally injected into the arc chamber from the electrode tip.

[0012] In the technical scheme, the gasket is made of polytetrafluoroethylene and has a thickness of 0.5-2 mm.

[0013] In the technical scheme, the protective layer of the cascade sheet has a coaxial three-layer structure: the inner layer is a molybdenum ring discharge channel for contacting plasma, the middle layer is a boron nitride insulation layer, and the outer layer is a copper cooling disc integrated with a serpentine water cooling channel.

[0014] In the technical scheme, the inner diameter of the stepped flange of the anode structure gradually decreases along the plasma jet direction, and the decreasing gradient is 5-15°.

[0015] In the technical scheme, the flow channel length of the serpentine water cooling channel is 3-5 times the diameter of the cascade sheet, and the water flow rate is 2-4 m 3 / h.

[0016] In the technical scheme, the gas inlet amount of the cathode assembly is 2-10 Nm 3 / h, and the gas flow rate of the cascade sheet gas inlet channel is 10%-30% of the cathode gas inlet amount.

[0017] Beneficial effects:

[0018] The present application solves the problems of heat ablation of the inner wall of the discharge channel and unstable discharge in the discharge process by increasing the gas inlet in the cascade sheet and adopting the serpentine cooling channel structure of the cascade sheet. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a structural schematic diagram of a high-power cascade arc plasma generator.

[0020] Wherein: 1-1 is a metal sleeve, 1-2 is a conductive electrode, 1-3 is a ceramic tube, 1-4 is a cathode seat, 1-5 is an observation window, 2-1 is a cascade sheet, 2-2 is a cascade sheet gas inlet channel, 2-3 is a serpentine water cooling channel, 3-1 is a discharge channel, and 3-2 is a stepped flange. DETAILED DESCRIPTION

[0021] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are only used to explain the present application, and the protection scope of the present application should include the entire content of the claims, and through the description of the following embodiments, those skilled in the art can fully realize the entire content of the claims of the present application.

[0022] Embodiment:

[0023] This embodiment describes the structure of a high-power cascade arc plasma generator, which includes a cathode structure, a cascade structure and an anode structure in sequence along the plasma generation and jet direction.

[0024] The cathode structure is composed of two cathode assemblies and a cathode seat 1-4 with an included angle α, the included angle α ranges from 0° to 120°, and the electrode ports of the two cathode assemblies are located in the same horizontal plane.

[0025] The cascade structure is composed of n cascade sheets 2-1 and gaskets stacked alternately, n is a positive integer ranging from 10 to 30, each cascade sheet is provided with a serpentine water cooling channel 2-3 and at least one cascade sheet gas inlet channel 2-2.

[0026] The anode structure is a stepped flange 3-2, and the inner wall of the discharge channel 3-1 is provided with a molybdenum ring protective layer.

[0027] The cathode assembly includes a coaxially arranged conductive electrode 1-2, a metal sleeve 1-1, and a ceramic tube 1-3; the metal sleeve 1-1 covers the conductive electrode 1-2, and the upper and lower ends are provided with cooling water interfaces, and the water flow direction is from bottom to top; the ceramic tube 1-3 covers the metal sleeve 1-1, and the outer side is provided with an inlet / outlet gas channel.

[0028] The discharge channel inner wall of the cathode seat 1-4 is provided with a molybdenum ring protective layer, and the cathode assembly is fixed to the cathode seat 1-4 by threads. An observation window 1-5 is arranged above the cathode seat 1-4.

[0029] The gas inlet path of the cathode structure is: the gas enters through the gap between the conductive electrode 1-2 and the metal sleeve 1-1, forms a vortex gas flow through the gas swirling ring, and finally is injected into the arc chamber from the electrode tip.

[0030] The gasket is made of polytetrafluoroethylene with a thickness of 0.5-2mm.

[0031] The protective layer of the cascade sheet is a coaxial three-layer structure: the inner layer is a molybdenum ring discharge channel (contacting plasma), the middle layer is a boron nitride insulating layer, and the outer layer is a copper cooling disc (integrating a serpentine water cooling channel).

[0032] The inner diameter of the stepped flange 3-2 of the anode structure gradually decreases along the plasma jet direction, and the reduction gradient is 5°-15°.

[0033] The flow channel length of the serpentine water cooling channel 2-3 is 3-5 times the diameter of the cascade sheet, and the water flow rate is 2-4m 3 / h.

[0034] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A high-power cascaded arc plasma generator, characterized in that: Along the direction of plasma generation and ejection, it includes, in sequence, a cathode structure, a cascade structure, and an anode structure; The cathode structure consists of two cathode assemblies and a cathode base arranged at an angle α, with the angle α ranging from 0° to 120°. The electrode ports of the two cathode assemblies are located on the same horizontal plane. The cascade structure is composed of n cascade plates and spacers stacked alternately, where n is a positive integer from 10 to 30. Each cascade plate is provided with a serpentine water-cooling channel and at least one air intake channel. The anode structure is a stepped flange, and its discharge channel inner wall is provided with a molybdenum ring protective layer.

2. The plasma generator according to claim 1, characterized in that: The cathode assembly includes a conductive electrode, a metal sleeve, and a ceramic tube arranged coaxially; the metal sleeve covers the conductive electrode and has cooling water interfaces at its upper and lower ends, with the water flow direction from bottom to top; the ceramic tube covers the metal sleeve and has an air inlet channel on its outer side.

3. The plasma generator according to claim 1, characterized in that: The inner wall of the discharge channel of the cathode holder is provided with a molybdenum ring protective layer, and the cathode assembly is fixed to the cathode holder by threads.

4. The plasma generator according to claim 2, characterized in that: The gas intake path of the cathode structure is as follows: gas is introduced through the gap between the conductive electrode and the metal sleeve, forms a vortex airflow through the swirling gas ring, and is finally injected into the arc chamber from the tip of the electrode.

5. The plasma generator according to claim 1, characterized in that: The gasket is made of polytetrafluoroethylene and has a thickness of 0.5~2mm.

6. The plasma generator according to claim 1, characterized in that: The protective layer of the cascaded plate has a coaxial three-layer structure: the inner layer is a molybdenum ring discharge channel that contacts the plasma, the middle layer is a boron nitride insulating layer, and the outer layer is a copper cooling plate integrated with a serpentine water cooling channel.

7. The plasma generator according to claim 1, characterized in that: The inner diameter of the stepped flange of the anode structure decreases gradually along the plasma jet direction, with a reduction gradient of 5° to 15°.

8. The plasma generator according to claim 1, characterized in that: The length of the serpentine water-cooling channel is 3 to 5 times the diameter of the cascaded plates, and the water flow rate is 2 to 4 m / s. 3 / h.

9. The plasma generator according to claim 1, characterized in that: The device has two air intake channels: one at the cathode assembly and the other at the cascade plate. The air intake volume of the cathode assembly is 2~10 Nm³. 3 / h, the air intake volume of the cascade plate air intake channel is 10%~30% of the cathode air intake volume.

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