RU2231936C1 - Three-phase ac plasma generator - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: proposed plasma generator designed to produce low-temperature plasma for physical experiments, plasma chemistry, metallurgy, and also for toxic and domestic waste recovery installations has electronic unit with housing accommodating three electrodes and nozzle unit. Electrode unit is provided with annular passage for feeding plasma-forming gas to electrodes. In addition electronic unit housing has three longitudinal through passages running to nozzle unit. Each electrode is provided with collar and is disposed in respective longitudinal through passage with clearance provided between collar and longitudinal through passage surface. Annular passage feeding plasma-forming gas to electrodes communicates with inlet of respective through passage. Clearance between electrode collar and surface of respective through passage measures between 0.3 and 2 mm. Generator supply voltage is 2 to 10 kV.

EFFECT: enhanced efficiency, simplified design, and reduced cost of device.

2 cl

Description

The invention relates to electrical engineering, is intended to obtain low-temperature plasma and can be used in physical experiments, plasma chemistry, metallurgy, as well as installations for the disposal of toxic and household waste.

Known three-phase alternating current plasma generator, US 4013867. It contains a housing, a gas chamber, many arc heaters on the housing and a nozzle. However, many arc heaters complicate the design and reduce its reliability.

Also known is a three-phase alternating current plasma generator, US 5801489, including an electrode unit, in the housing of which are placed both the initial and working parts of the electrodes, as well as a plasma injector, in particular a plasma torch, which allows ionization of the space between the electrodes; a nozzle block is connected to the electrode block in such a way that the cavities form a common space — an electric discharge chamber; at the exit of the nozzle block there is a nozzle through which the generated plasma leaves; at the entrance to the electrode block there is a ring for supplying a plasma-forming gas to the electric discharge chamber.

Its main disadvantage is the low efficiency (not higher than 60%).

This technical solution is taken as a prototype of the present invention.

In addition, the disadvantage of this device is the need for an injector (plasma torch), which ionizes the space between the electrodes, since the injector is a very expensive and complex design that requires a separate power source.

The present invention is based on the solution of the problem of increasing the efficiency of the device, as well as simplification and cheapening of its design.

According to the invention, this problem is solved due to the fact that in a three-phase alternating current plasma generator comprising an electrode unit, in the housing of which three electrodes are fixed, and a nozzle unit, the electrode unit is provided with an annular channel for supplying plasma-forming gas to the electrodes in the electrode unit case there are three longitudinal through channels extending into the nozzle block, each of the electrodes is provided with a shoulder and placed in a corresponding longitudinal through channel with a gap between the shoulder and the surface of the longitudinal the through channel, and the annular channel for supplying plasma-forming gas to the electrodes communicates with each of the longitudinal through channels in the area between the collar of the electrode and the entrance to the corresponding longitudinal through channel; the gap between the collar of the electrode and the surface of the corresponding through channel is from 0.3 to 2 mm, while the voltage supplying the generator is 2-10 kV.

The applicant has not identified sources containing information about technical solutions identical to the present invention, which allows us to conclude that it meets the criterion of "novelty."

The implementation of the distinguishing features of the invention provides (in combination with the characteristics indicated in the restrictive part of the claims) an important fundamentally new property of the object: the electric arc is not located in a wide chamber, but in narrow through channels, and the plasma-forming gas supplied separately to each channel tightly compresses an electric arc, which dramatically increases the heat transfer between the arc and the gas, while the efficiency increases to 90%, that is, by 30% in comparison with the prototype. In addition, due to the presence of a collar at the electrodes and a small gap between the collar and the surface of the through channel, a breakdown of the gap is ensured, the appearance and reignition of the electric arc when the current value passes through zero without the use of special means such as an injector.

The applicant has not found any sources of information containing information about the impact of the claimed distinctive features on the technical result achieved as a result of their implementation. This, according to the applicant, indicates that this technical solution meets the criterion of "inventive step".

The invention is illustrated by drawings, which depict:

figure 1 - device, side view of the nozzle block;

figure 2 is a section along aa in figure 1;

figure 3 is a section along BB in figure 2;

figure 4 is a device in a perspective view.

The three-phase alternating current plasma generator includes an electrode unit 1. Three electrodes 2, 3, 4 are fixed in its body. The nozzle unit body 5 can be made integral with the body of the electrode unit 1 or separately. The electrode unit 1 is equipped with an annular channel 6 for supplying a plasma-forming gas to the electrodes 2, 3, 4. In the housing of the electrode unit 1 there are three longitudinal through channels 7, 8, 9 that exit into the nozzle unit 5.

Each of the electrodes is provided with a collar 10 and is placed in a corresponding longitudinal through channel with a gap between the collar and the channel surface. In an optimal embodiment, this gap is from 0.3 to 2 mm with a voltage of 2 to 10 kV supplying the generator.

An annular channel for supplying plasma-forming gas to the electrodes is in communication with each of the longitudinal through channels in the area between the electrode collar and the entrance to the corresponding longitudinal through channel through grooves 12, 13, 14 made in the body of the electrode unit 1.

The device operates as follows.

From a compressor (not shown in the drawings), a plasma-forming gas, in a specific example, air is supplied to the annular channel 6. Then the gas enters through the grooves 12, 13, 14, respectively, into the longitudinal through channels 7, 8, 9, while the gas moves under angle to the channel wall and twists. This increases the residence time of the gas in each of the channels 7, 8, 9 and stabilizes the resulting electric arc; to create an arc, the electrodes 2, 3, 4 are energized, in a specific example, 6000 V. In the gaps 11 between the collars 10 of the electrodes and the walls of the channels 7, 8, 9, an electric arc arises, which is blown by the plasma gas in the direction of the nozzle block. Under the action of turbulent flows of plasma-forming gas, arcs from adjacent channels come into contact and one arc is formed from the end of one electrode to the end of the other. Since the arc burns in a narrow channel and has a considerable length, and the plasma-forming gas moves between the channel wall and the arc, intense heat exchange occurs between the arc and gas, which significantly increases the efficiency of the device.

To implement this device, industrial equipment customary for this field of technology has been used, which determines the compliance of the invention with the criterion of “industrial applicability”.

Claims (2)

1. A three-phase alternating current plasma generator comprising an electrode unit, three electrodes are fixed in the housing, and a nozzle unit, the electrode unit being provided with an annular channel for supplying plasma-forming gas to the electrodes, characterized in that three longitudinal through channels are made in the electrode unit body outgoing into the nozzle block, each of the electrodes is provided with a shoulder and is placed in the corresponding longitudinal through channel with a gap between the shoulder and the surface of the longitudinal through channel, and the annular channel for the plasma-forming gas supply to the electrodes communicates with each of the longitudinal through channels in the zone between the electrode collar and the entrance to the corresponding longitudinal through channel. 2. The three-phase alternating current plasma generator according to claim 1, characterized in that the gap between the electrode collar and the surface of the corresponding through channel is from 0.3 to 2 mm, while the voltage supplying the generator is 2-10 kV.

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