CN114885485A - Arc plasma generator - Google Patents

Abstract

The invention provides an arc plasma generator, which relates to the technical field of plasma generators and comprises a cathode, an insulating support component, an intermediate part, an air inlet part, an insulating part and an anode; the cathode is connected to the top end of the insulating support component; the middle piece, the air inlet piece, the insulating piece and the anode are clamped on the insulating support component from top to bottom, the middle piece is provided with a first plasma channel, the cathode penetrates through the top end of the insulating support component and extends into the first plasma channel, the anode is provided with a second plasma channel communicated with the first plasma channel through the air inlet piece and the insulating piece, and the air inlet piece is used for distributing shielding gas into the second plasma channel and enabling the surface of the second plasma channel to form spiral shielding gas. The arc plasma generator can increase the arc voltage, reduce the arc current, restrain the plasma jet, improve the characteristics of the plasma in the arc root attaching area, stabilize the arc and inhibit the electrode ablation.

Description

Arc plasma generator

Technical Field

The invention relates to the technical field of plasma generators, in particular to an arc plasma generator.

Background

An arc plasma generator is a device that generates high-temperature plasma by electric discharge between electrodes, and generally, the electric discharge between the electrodes can generate a high temperature of ten thousand degrees or more, and the temperature of the generated plasma jet is also ten thousand degrees or more. Therefore, the dc arc plasma generator is generally applied to various scenes as a high temperature heat source. For example, high temperature electric arcs can melt metal and ceramic powders for preparing various functional coatings, can be used for waste treatment in the field of environmental protection, can also be used for synthesis of ultrafine powder, cutting, even melting of steel and iron, and the like, and have very wide application in various fields.

Currently, there are two significant problems in the practical application of arc plasma generators: the first is instability caused by the jump of an arc root along the axial direction, which affects the production process; the second is anode ablation caused by the concentration and attachment of arc roots to the electrode surface, which not only affects the production process, but also directly determines the service life of the generator. Therefore, the principle of electrode ablation in the arc plasma generator is researched, a new scheme for reducing the electrode ablation is provided, and the method has important significance for improving the production process and prolonging the service life of the arc plasma generator.

In most plasma generators, the main cause of anode erosion is local long-term high-temperature overheating, and the main cause of local long-term high-temperature overheating is high concentration of joule heat caused by long-term stable adhesion of arc roots to a certain fixed position on the electrode surface. It is well known that joule heating is proportional to the square of the current, and that reducing the arc current reduces joule heating to a large extent, reduces electrode erosion and extends the useful life of the generator. The input power is equal to the voltage multiplied by the current, and under a certain rated power of the plasma generator, the arc current can be reduced by increasing the arc voltage. The methods for increasing the arc voltage that are widely used at present are: the middle section of the suspension potential, the multistage air inlet blowing and pulling electric arc, the sectional anode structure and the like are added between the electrodes. Another method to reduce electrode erosion is to avoid the arc from sticking to a fixed area on the electrode surface for a long time, and to increase the heated area of the anode by rotating the arc circumferentially on the electrode surface. The main current ways to rotate the arc circumferentially around the electrode surface are: the arc is magnetically rotated, namely, the arc is driven to rotate along the circumferential direction of the surface of the electrode under the action of the magnetic field of an electrified solenoid by applying the electrified solenoid on the outer side of the arc plasma generator. This method, however, requires not only the addition of a solenoid, but also the application of a direct current thereto to generate a magnetic field. If the required magnetic field strength is large, a matched cooling device is required to be added to the electrified solenoid. Thus, magnetic spin arcing adds considerably to the complexity and unreliability of plasma generator systems.

Disclosure of Invention

The invention aims to provide an arc plasma generator which can increase the arc voltage, reduce the arc current, restrain the plasma jet, improve the characteristics of plasma in an arc root attaching area, stabilize the arc and inhibit electrode ablation.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides an arc plasma generator, which comprises a cathode, an insulating support component, an intermediate piece, an air inlet piece, an insulating piece and an anode, wherein the cathode is arranged on the insulating support component;

the cathode is connected to the top end of the insulating support component;

the middle piece, the air inlet piece, the insulating piece and the anode are clamped on the insulating support component from top to bottom, the middle piece is provided with a first plasma channel, the cathode penetrates through the top end of the insulating support component and extends into the first plasma channel and is used for filling working medium gas into the first plasma channel, the anode is provided with a second plasma channel, the second plasma channel is communicated with the first plasma channel through the air inlet piece and the insulating piece, and the air inlet piece is used for distributing protective gas into the second plasma channel and enabling the surface of the second plasma channel to form spiral protective gas.

Furthermore, the cathode comprises an upper substrate, a cathode middle part and a lower tip, the upper substrate is connected with the top end of the insulating support component, the upper substrate is provided with at least one working medium gas inlet communicated with the first plasma channel, one end of the cathode middle part is fixedly connected with the upper substrate, the other end of the cathode middle part is clamped with the lower tip, and the lower tip is positioned in the first plasma channel;

and a cooling cavity is arranged in the middle of the cathode, and the upper substrate is provided with a cooling working medium inlet channel and a cooling working medium outlet channel which are communicated with the cooling cavity.

Further, the insulating support assembly comprises a top insulating layer, a bottom support and a locking member, wherein the top insulating layer is connected with the bottom support through the locking member so as to clamp the intermediate member, the air inlet member, the insulating member and the anode between the top insulating layer and the bottom support, and the bottom insulating layer is mounted on one side of the bottom support facing the top insulating layer.

Furthermore, the first plasma channel comprises an air inlet area and a discharge area, two ends of the discharge area are respectively communicated with the air inlet area and the second plasma channel, and the caliber of one end, close to the discharge area, of the air inlet area is gradually reduced along the air inlet direction.

Further, the second plasma passageway is including the expansion section, the straight section of thick bamboo section and the shrink beam section that from top to bottom communicate gradually, the expansion section is along being close to gradually the direction bore grow of the straight section of thick bamboo section of suddenly expanding gradually, the bore of the straight section of thick bamboo section of suddenly expanding is greater than the bore of the arbitrary department of expansion section and with form the circular bead that suddenly expands between the expansion section, shrink beam section is along keeping away from gradually the direction bore of the straight section of suddenly expanding diminishes gradually.

Further, an air distribution cavity is formed between the air inlet part and the intermediate part, an air inlet channel communicated with the air distribution cavity and used for introducing the shielding gas is arranged on the side wall of the air inlet part, a first shielding gas channel is formed in the air inlet part, and two ends of the first shielding gas channel are respectively communicated with the air distribution cavity and one end, away from the sudden expansion straight barrel section, of the expansion section;

the first protection gas channel is obliquely arranged, and the axis of the first protection gas channel is different from the axis of the expansion section in surface, so that the protection gas discharged from the first protection gas channel forms spiral airflow in the expansion section.

Furthermore, the air inlet part is also provided with an air inlet communicated with the air distribution cavity, the insulating part is provided with a vent hole, the anode is provided with an exhaust hole, the exhaust hole extends from the top surface of the anode to the sudden expansion shoulder, and the air inlet, the vent hole and the exhaust hole are sequentially communicated to form a second protective air channel.

Furthermore, the exhaust holes are obliquely arranged, and the axes of the exhaust holes are different from the axes of the sudden-expansion straight cylinder section in surface, so that the protective gas exhausted from the second protective gas channel forms spiral airflow in the sudden-expansion straight cylinder section.

Further, the cooling device also comprises a first cooling sleeve and a second cooling sleeve;

the first cooling sleeve is sleeved outside the intermediate piece, and a first cooling cavity is formed between the first cooling sleeve and the intermediate piece;

the second cooling sleeve is sleeved outside the anode and forms a second cooling cavity with the anode;

the air inlet piece is clamped between the first cooling sleeve and the second cooling sleeve, and a cooling working medium conducting hole for communicating the first cooling cavity with the second cooling cavity is formed in the air inlet piece.

Furthermore, a first cooling channel with two ends communicated with the first cooling cavity is arranged in the intermediate piece, one end of the first cooling channel is higher than the other end, and the caliber of one end is larger than that of the other end;

and a second cooling channel with two ends communicated with the second cooling cavity is arranged in the anode, one end of the second cooling channel is higher than the other end, and the caliber of one end is larger than that of the other end.

When the arc plasma generator is used, working medium gas enters the first plasma channel from the cathode and then enters the second plasma channel through the air inlet part and the insulating part, arc plasma jet flow is generated between the cathode and the anode, plasma finally flows out of the second plasma channel, and protective gas enters the second plasma channel through the distribution screw of the air inlet part to form a gas film to restrain the arc plasma and protect the anode.

Compared with the prior art, the arc plasma generator provided by the invention has the following advantages:

1. the arc is lengthened by additionally arranging the middleware, the arc voltage is increased, and the arc current is reduced;

2. the air inlet piece can distribute the protective gas into the second plasma channel, and an air film is formed in the second plasma channel, so that plasma jet is effectively restrained, the characteristics of plasmas in an arc root attachment area are improved, electric arcs are stabilized, electrode ablation is inhibited, and the service life of the plasma generator is prolonged;

3. the electrode has a simple relative structure, can effectively inhibit electrode ablation on the basis of not introducing an additional device, and prolongs the service life.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a cross-sectional view of an arc plasma generator according to an embodiment of the present invention;

FIG. 2 is a top view of an arc plasma generator according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view A-A of FIG. 2;

FIG. 4 is a longitudinal sectional view of an anode provided in an embodiment of the present invention;

FIG. 5 is a perspective view of an anode provided by an embodiment of the present invention;

FIG. 6 is a top view of an anode provided by an embodiment of the present invention;

FIG. 7 is an enlarged view of FIG. 1 at B;

FIG. 8 is a schematic three-dimensional structure of an air intake component according to an embodiment of the present invention;

fig. 9 is a perspective view of an insulator according to an embodiment of the present invention.

Icon: 1-a cathode; 11-an upper substrate; 111-working medium gas inlet; 112-cooling working medium inlet channel; 113-a cooling medium discharge channel; 12-cathode middle; 121-a cooling chamber; 13-lower tip; 14-a screw; 2-an insulating support member; 21-a top insulating layer; 22-bottom insulating layer; 23-a bottom support; 24-a locking member; 3-middleware; 31-a first plasma channel; 311-an air intake zone; 312-discharge area; 32-a first cooling channel; 33-a projection; 4-an air inlet; 41-an intake passage; 42-a first shielding gas channel; 43-an air intake; 44-cooling working medium via hole; 5-an insulating member; 51-a vent; 6-an anode; 61-a second plasma channel; 611-an expansion section; 612-sudden expansion straight barrel section; 613-contracting the beam section; 614-a sudden expansion shoulder; 62-vent hole; 63-a second cooling channel; 7-air distribution cavity; 8-a first cooling sleeve; 81-cooling working medium outlet; 9-a second cooling jacket; 91-cooling medium inlet.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The present embodiment is directed to an arc plasma generator, as shown in fig. 1, including a cathode 1, an insulating support member 2, an intermediate member 3, an air inlet member 4, an insulating member 5, and an anode 6; the cathode 1 is connected to the top end of the insulating support component 2; the middle part 3, the air inlet part 4, the insulating part 5 and the anode 6 are clamped on the insulating support component 2 from top to bottom, the middle part 3 is provided with a first plasma channel 31, the cathode 1 penetrates through the top end of the insulating support component 2 and extends into the first plasma channel 31 and is used for filling working medium gas into the first plasma channel 31, the anode 6 is provided with a second plasma channel 61, the second plasma channel 61 is communicated with the first plasma channel 31 through the air inlet part 4 and the insulating part 5, and the air inlet part 4 is used for distributing shielding gas into the second plasma channel 61 and enabling the surface of the second plasma channel 61 to form spiral shielding gas.

The operation of the arc plasma generator is briefly described below with reference to fig. 3:

the working medium gas enters the first plasma channel 31 through the cathode 1 and forms plasma, then enters the second plasma channel 61 through the gas inlet 4 and the insulating member 5, and finally flows out of the second plasma channel 61. The shielding gas enters the second plasma channel 61 through the gas inlet 4 and forms a spiral shielding gas on the surface of the second plasma channel 61, so that the arc plasma is restrained and the anode 6 is protected.

In the dc arc plasma generator, nitrogen gas and air, which are relatively inexpensive, are generally used as the plasma forming gas (working medium gas). Taking nitrogen as an example, the enthalpy value of the nitrogen arc is relatively high, the arc root of the anode is very concentrated, and the direct attachment on the surface of the anode 6 often causes serious electrode ablation due to overlarge current density and overhigh heat flow density, so that the service life of the equipment is shortened. An inert gas shield gas such as argon is injected into the anode 6 from the gas inlet 4, thereby forming a shield gas layer in the near-electrode region. The physical property of the protective gas is not easy to shrink relative to working medium gases such as nitrogen, and the generated plasma expands relatively. The nitrogen arc root passes through the protective gas layer before being attached to the surface of the anode 6, the protective gas layer ionizes the protective gas to form a relatively mild arc root, so that the characteristic of arc plasma in the anode arc root attachment area is improved, the attachment area of the arc root is increased, the heat flux density flowing to the anode 6 is reduced, electrode ablation is inhibited, and the service life of the arc plasma generator is prolonged.

The structure of the cathode 1 is specifically described below:

in some embodiments, as shown in fig. 1-3, cathode 1 includes an upper substrate 11, a cathode middle 12, and a lower tip 13.

The upper substrate 11 is connected to the top end of the insulating support assembly 2, specifically, the upper substrate 11 may have a disc-shaped structure, and the upper substrate 11 is connected to the insulating support assembly 2 through a plurality of screws. The screws may be configured in two, three, four, etc., preferably in four, with the four screws being evenly distributed around the axis of the upper base plate 11. The upper substrate 11 has at least one working gas inlet 111 communicating with the first plasma channel 31, and the working gas can enter the first plasma channel 31 from the working gas inlet 111. Preferably, two gas inlet pipes are connected to the upper substrate 11, and each of the two gas inlet pipes has one working medium gas inlet 111.

Wherein, one end of the cathode middle part 12 is fixedly connected with the upper substrate 11, the other end is clamped with the lower tip 13, and the lower tip 13 is positioned in the first plasma channel 31. Specifically, the cathode middle part 12 is in a pencil head shape, and one end of the cathode middle part 12 with a larger diameter size is fixed with the upper substrate 11 by welding; the lower tip 13 is in a taper shape, and the lower tip 13 is clamped inside the other end of the cathode middle part 12 in an interference fit manner.

The upper substrate 11 and the cathode middle part 12 are preferably made of red copper, and the lower tip 13 is preferably made of high temperature resistant material, preferably tungsten, hafnium, etc.

On the basis of the above embodiments, in some embodiments, in order to avoid the over-temperature of the cathode 1 during operation, as shown in fig. 1, a cooling chamber 121 is provided in the cathode middle portion 12, and the upper substrate 11 has a cooling medium inlet passage 112 and a cooling medium outlet passage 113 communicating with the cooling chamber 121.

The cooling working medium can enter the cooling cavity 121 from the cooling working medium inlet channel 112 and is discharged from the cooling working medium outlet channel 113, so that the heat of the middle part 12 of the cathode is taken away, and the effect of cooling the lower tip 13 is further achieved.

Specifically, the cooling cavity 121 is arranged in the middle of the cathode 12 facing the middle of the upper substrate 11, a first through hole is formed in the middle of the upper substrate 11, a second through hole is formed beside the first through hole, a liquid inlet pipe communicated with the cooling cavity 121 is inserted into the first through hole, the liquid inlet pipe forms a cooling working medium inlet channel 112, a liquid outlet pipe communicated with the cooling cavity 121 is inserted into the second through hole, and the liquid outlet pipe forms a cooling working medium outlet channel 113.

As shown in fig. 1, in order to facilitate the communication between the liquid inlet pipe and the liquid outlet pipe, the cooling cavity 121 includes a cylindrical cavity coaxial with the upper substrate 11 and a side cavity communicated with one side of the cylindrical cavity, the liquid inlet pipe extends into the cylindrical cavity, and the liquid outlet pipe is directly communicated with the side cavity.

The insulating support member 2 is specifically described below:

in some embodiments, as shown in fig. 1, the insulating support assembly 2 includes a top insulating layer 21, a bottom insulating layer 22, a bottom support 23, and a locking member 24, the top insulating layer 21 is connected with the bottom support 23 by the locking member 24, and the bottom insulating layer 22 is mounted on a side of the bottom support 23 facing the top insulating layer 21. The insulating support assembly 2 is simple in structure and can effectively limit the axial positions of the intermediate member 3, the air inlet member 4, the insulating member 5 and the anode 6.

The locking member 24 may have various structures, for example, the locking member 24 includes a screw and a nut, or the locking member includes a snap that can be engaged with each other, that is, the locking member 24 may be the one mentioned in the above embodiment where the structure can connect the top insulating layer 21 and the bottom supporting member 23.

In at least one embodiment, as shown in fig. 1, the locking member 24 comprises a screw and a nut, the top insulating layer 21 is formed with a plurality of insertion holes, and the bottom supporting member 23 is formed with stepped counter bores corresponding to the insertion holes. The screw rod runs through cartridge hole and ladder counter bore, and the spacing head of screw rod bottom holds in the ladder counter bore, and the nut is revolved in the top of screw rod. After the nut is tightened, the intermediate piece 3, the air inlet piece 4, the insulator 5 and the anode 6 are clamped between the top insulating layer 21 and the bottom support 23.

Specifically, a stepped through hole is formed in the middle of the bottom support member 23, the bottom end of the anode 6 is accommodated in the stepped through hole, and a sealing ring is clamped between the anode 6 and the stepped through hole to ensure good sealing performance between the anode 6 and the stepped through hole.

In addition, the top insulating layer 21 and the bottom insulating layer 22 are made of insulating materials, such as teflon, ceramic, and the like.

For the convenience of limiting the bottom insulating layer 22, a mounting groove is formed in one side of the bottom supporting piece 23 facing the top insulating layer 21, and the bottom insulating layer 22 is mounted in the mounting groove. When the outer jacket of the anode 6 is provided with a cooling structure, the provision of the bottom insulating layer 22 may serve to electrically insulate the anode 6 from the cooling structure. Therefore, when the cooling structure is not provided on the outside of the anode 6, the bottom insulating layer 22 may not be provided.

The structure of the middleware 3 is specifically explained below:

in some embodiments, as shown in fig. 3, the first plasma channel 31 includes a gas inlet region 311 and a discharge region 312, and both ends of the discharge region 312 communicate with the gas inlet region 311 and the second plasma channel 61, respectively.

Because the tip that the cathode stretched into air intake zone 311 is the taper shape, for making air intake zone 311's shape can adapt to negative pole 1, air intake zone 311 is close to the one end of discharge region 312 and reduces along the direction bore that admits air gradually, can play the guide effect to admitting air simultaneously, guarantees to admit air can smoothly, get into discharge region 312 fast, avoids appearing the stagnant area that admits air.

As shown in fig. 3, the arrester region 312 may be cylindrical.

Specifically, the intermediate member 3 is a columnar structure, the material is preferably red copper or tungsten, as shown in fig. 3, a protruding portion 33 is arranged in the middle of one end of the intermediate member 3, which is away from the cathode 1, a first air hole is formed in the middle of the air inlet member 4, the protruding portion 33 extends into the first air hole of the air inlet member 4, and a gap is formed between the protruding portion 33 and the surface of the first air hole.

In order to avoid the temperature of the intermediate part 3 being too high during the operation, as shown in fig. 3, a first cooling channel 32 is provided in the intermediate part 3, and the cooling liquid can enter and exit the intermediate part 3 through the first cooling channel 32, thereby achieving the effect of cooling the intermediate part 3.

The first cooling passage 32 may be provided in one, two, three, or the like. When the first cooling passage 32 is provided in plural, the respective first cooling passages 32 may intersect in whole or in part, and the respective first cooling passages 32 may not intersect.

In some embodiments, the first cooling channel 32 extends in a straight line, and one end of the first cooling channel 32 is higher than the other end, so as to increase the contact area between the first cooling channel 32 and the intermediate member 3. The caliber of one end of the first cooling channel 32 may be larger than the caliber of the other end, so that the cooling working medium has a tendency to flow from the end with the smaller opening to the end with the larger opening, promoting the flow of the cooling working medium.

The height direction may be considered as a direction parallel to the axial direction of the intermediate member 3, and the end closer to the cathode 1 is a higher end.

In at least one embodiment, the first cooling passage 32 has a smaller opening at the lower end than at the upper end.

The structure of the anode 6 is specifically described below:

in some embodiments, as shown in fig. 4, the second plasma channel 61 includes an expanding section 611, a sudden-expansion straight cylinder section 612, and a contraction beam flow section 613 which are sequentially connected from top to bottom, the aperture of the expanding section 611 gradually increases along a direction gradually approaching the sudden-expansion straight cylinder section 612, the aperture of the sudden-expansion straight cylinder section 612 is greater than the aperture of any position of the expanding section 611 and forms a sudden-expansion shoulder 614 facing the sudden-expansion straight cylinder section 612 with the expanding section 611, and the aperture of the contraction beam flow section 613 gradually decreases along a direction gradually departing from the sudden-expansion straight cylinder section 612.

When the plasma torch is used, firstly, an auxiliary arc striking circuit is started to generate arc plasma jet between the cathode 1 and the anode 6, then the auxiliary arc striking circuit is disconnected, the plasma jet expands and accelerates through the expansion section 611 at the upper part of the anode 6, the arc root is attached to the sudden-expansion straight cylinder section 612 under the action of pneumatic force, and finally the plasma jet flows out from the tail contraction beam section 613.

Specifically, the anode 6 is made of an electrically and thermally conductive material, preferably red copper.

In order to avoid the temperature of the anode 6 being too high during operation, as shown in fig. 5, a second cooling channel 63 is provided in the anode 6, and the cooling liquid can enter and exit the anode 6 through the second cooling channel 63, thereby cooling the anode 6.

The second cooling passage 63 may be provided in one, or two, three, four, or the like.

Specifically, referring to fig. 5 as an example, the number of the second cooling passages 63 is four, and the four second cooling passages 63 are arranged in parallel with each other. Two of the four second cooling channels 63 are distributed on one side of the second plasma channel 61, and the other two are distributed on the other side of the second plasma channel 61.

In some embodiments, similar to the first cooling channel 32, the second cooling channel 63 extends in a straight line, and one end of the second cooling channel 63 is higher than the other end to increase the contact area of the second cooling channel 63 and the anode 6. The bore of one end of the second cooling channel 63 may be larger than the bore of the other end, so that the cooling medium has a tendency to flow from the end with the smaller opening to the end with the larger opening, promoting the flow of the cooling medium.

The height direction may be considered as a direction parallel to the axial direction of the anode 6, and the end close to the cathode 1 is a higher end.

In at least one embodiment, as shown in FIG. 5, the second cooling channel 63 has a smaller opening at the lower end than at the upper end.

The structure of the air intake 4 will be specifically described below:

air inlet 4 is electrically conductive material, preferably adopts the red copper of being convenient for processing.

In some embodiments, as shown in fig. 7, in order to facilitate distribution of the shielding gas to different positions of the second plasma channel 61, a gas distribution chamber 7 is formed between the gas inlet member 4 and the intermediate member 3, the side wall of the gas inlet member 4 has a gas inlet channel 41 communicating with the gas distribution chamber 7, the shielding gas can enter the gas distribution chamber 7 through the gas inlet channel 41, and the shielding gas is distributed into the second plasma channel 61 through the gas distribution chamber 7.

Specifically, as shown in fig. 8, the air inlet 4 is provided with a first shielding air passage 42, and two ends of the first shielding air passage 42 are respectively communicated with the air distribution chamber 7 and one end of the expansion section 611, which is away from the sudden expansion straight section 612. As shown in fig. 7, the shielding gas in the gas distribution chamber 7 can enter the gap between the gas inlet 4 and the projection 33 through the first shielding gas passage 42, and then enter the expansion section 611 through the second gas hole in the middle of the insulator 5.

In some embodiments, as shown in fig. 8, the first shielding gas channel 42 is disposed obliquely, and the axis of the first shielding gas channel 42 is out of plane with the axis of the expanding section 611, so that the shielding gas has a tendency to move circumferentially along the expanding section 611 after entering the expanding section 611, thereby forming a spiral gas flow in the expanding section 611, and constraining the plasma jet of the expanding section 611.

In some embodiments, in order to confine the plasma jet of the cylindrical section 612, as shown in fig. 8, the air inlet 4 further has an air inlet 43 communicating with the air distribution chamber 7, the air inlet 43 and the first shielding gas channel 42 can be alternately distributed around the axis of the air inlet 4, as shown in fig. 9, the insulating member 5 has a vent hole 51, as shown in fig. 5 and 6, the anode 6 has an air outlet 62, and the air outlet 62 extends from the top surface of the anode 6 to the enlarged shoulder 614.

The shielding gas in the air distribution chamber 7 can enter the vent hole 51 from the air inlet hole 43 and then enter the sudden expansion straight cylinder section 612 through the air outlet hole 62, namely, the air inlet hole 43, the vent hole 51 and the air outlet hole 62 are sequentially communicated to form a second shielding gas channel, and the shielding gas enters the sudden expansion straight cylinder section 612 from the sudden expansion shoulder 614, so that the shielding gas can form a shielding gas layer in the region of the sudden expansion straight cylinder section 612 close to the electrode. The second shielding gas channel is matched with the first shielding gas channel 42 to be jointly filled with shielding gas, so that the attaching area of the arc root can be effectively increased, and the heat flux density flowing to the anode 6 is reduced, thereby inhibiting the ablation of the anode 6 and prolonging the service life of the arc plasma generator.

The number of the exhaust holes 62 may be one, or two, three, four, or the like.

In at least one embodiment, as shown in fig. 5, the exhaust holes 62 are arranged in four, and the four exhaust holes 62 are evenly distributed around the axis of the anode 6.

In some embodiments, in order to enable the shielding gas discharged from the gas discharge holes 62 to naturally form swirling gas in the cylindrical section 612, the gas discharge holes 62 may be extended linearly and arranged obliquely, and the axis of the gas discharge holes 62 is different from the axis of the cylindrical section 612, so that the shielding gas has a tendency to move circumferentially along the cylindrical section 612 after entering the cylindrical section 612, thereby forming a spiral gas flow in the cylindrical section 612.

The exhaust holes 62 are convenient to process, and can effectively enable the protective gas to form a rotational flow air film in the sudden expansion straight cylinder section 612. On the basis of the above embodiment, the axes of the air intake holes 43 in the air intake 4 may be parallel to the axis of the air intake 4, and the axes of the ventilation holes 51 in the insulator 5 may be parallel to the axis of the insulator 5, i.e., the air intake 4 and the insulator 5 pass the shielding gas into the exhaust holes 62 along the axes.

Of course, the vent hole 62 is not limited to the above structure, and the vent hole 62 may also be arc-shaped, spiral-shaped, etc. so that the shielding gas has a tendency to move along the circumferential direction of the cylindrical section 612 through the guiding function of the vent hole 62.

Further, the material of the insulating member 5 may be polytetrafluoroethylene, ceramic, or the like.

The following describes a cooling structure of the arc plasma generator in detail:

the cooling working medium can directly enter the first cooling channel 32 of the intermediate part 3 and the second cooling channel 63 of the anode 6 through external pipelines to realize cooling of the two.

To improve the cooling effect, in some embodiments, as shown in fig. 3, the arc plasma generator further includes a first cooling sleeve 8 and a second cooling sleeve 9; the first cooling sleeve 8 is sleeved outside the intermediate piece 3 and forms a first cooling cavity with the intermediate piece 3; the second cooling sleeve 9 is sleeved outside the anode 6 and forms a second cooling cavity with the anode 6; the air inlet 4 is clamped between the first cooling sleeve 8 and the second cooling sleeve 9, and as shown in fig. 7 and 8, the air inlet 4 is provided with a cooling medium conducting hole 44 for communicating the first cooling cavity with the second cooling cavity.

As shown in fig. 3, the first cooling jacket 8 has a cooling medium outlet 81 and the second cooling jacket 9 has a cooling medium inlet 91. The cooling medium can flow into the second cooling chamber through the cooling medium inlet 91, flow into the first cooling chamber through the cooling medium conducting hole 44, and finally flow out from the cooling medium outlet 81.

The cooling medium conducting hole 44 may be arranged in plural, and the plural cooling medium conducting holes 44 are uniformly arranged around the axis of the air intake 4.

Specifically, the first cooling channel 32 in the intermediate part 3 is communicated with the first cooling cavity, and the second cooling channel 63 in the anode 6 is communicated with the second cooling cavity, so that the cooling working medium can enter the intermediate part 3 and the inside of the anode 6 to be cooled, and a better heat dissipation effect is achieved.

It should be noted that, in order to ensure that the arc plasma generator has a good sealing effect, a sealing ring is additionally arranged between two adjacent structures. For example, the bottom end of the second cooling sleeve 9 abuts against the annular groove at the top end of the bottom insulating layer 22, and a sealing ring is clamped between the second cooling sleeve 9 and the annular groove to prevent the cooling medium from leaking outwards.

The operation of the arc plasma generator is described in detail below with reference to fig. 3:

before the arc plasma generator is started, protective gas (generally gas with relatively low enthalpy value and easy to break down and ionize) with a certain flow rate is fed through the gas inlet 4, then working medium gas enters the gas inlet region 311 and the discharge region 312 from the 2 working medium gas inlets 111 on the cathode 1 to generate plasma, plasma jet flows into the anode 6 through the gas inlet 4 and the insulating member 5, is expanded and accelerated through the expansion section 611 on the upper part of the anode 6, is attached to the sudden-expansion straight cylinder section 612 under the action of pneumatic force, and finally flows out from the tail contraction beam section 613.

The flow of the protective gas can be reasonably adjusted according to the use power of the arc plasma generator. The shielding gas enters the gas distribution chamber 7 through the gas inlet channels 41 on the periphery of the gas inlet component 4, then one path of the shielding gas passes through the first shielding gas channel 42 and then flows to the expanding section 611 on the upper part of the anode 6 in a rotating mode, and the other path of the shielding gas flows out of the sudden expansion shoulder 614 of the anode 6 through the second shielding gas channel and flows to the sudden expansion straight cylinder section 612 on the lower part of the anode 6, so that gas film confined arc plasma is formed and the anode is protected.

In order to improve the heat dissipation efficiency of the generator, in the above process, the cooling medium flows from the cooling medium inlet 91 into the second cooling chamber, flows into the first cooling chamber through the cooling medium conducting hole 44, and finally flows out from the cooling medium outlet 81.

The wires of the cathode 1 and the anode 6 may be connected to the outside of the cathode 1 and the bottom support 23, respectively, and an auxiliary arc ignition circuit may be connected to the outside of the air intake 4.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. An arc plasma generator is characterized by comprising a cathode (1), an insulating support component (2), an intermediate piece (3), an air inlet piece (4), an insulating piece (5) and an anode (6);

the cathode (1) is connected to the top end of the insulating support component (2);

the intermediate piece (3), the air inlet piece (4), the insulating piece (5) and the anode (6) are clamped on the insulating support component (2) from top to bottom, the intermediate piece (3) is provided with a first plasma channel (31), the cathode (1) penetrates through the top end of the insulating support assembly (2) and extends into the first plasma channel (31) and is used for filling working medium gas into the first plasma channel (31), the anode (6) is provided with a second plasma channel (61), the second plasma channel (61) is communicated with the first plasma channel (31) through the air inlet piece (4) and the insulating piece (5), the air inlet piece (4) is used for distributing the shielding gas into the second plasma channel (61) and enabling the surface of the second plasma channel (61) to form spiral shielding gas.

2. The arc plasma generator according to claim 1, characterized in that the cathode (1) comprises an upper base plate (11), a cathode middle part (12) and a lower tip (13), the upper base plate (11) is connected with the top end of the insulating support component (2), the upper base plate (11) is provided with at least one working medium gas inlet (111) communicated with the first plasma channel (31), one end of the cathode middle part (12) is fixedly connected with the upper base plate (11), the other end is clamped with the lower tip (13), and the lower tip (13) is positioned in the first plasma channel (31);

and a cooling cavity (121) is arranged in the middle part (12) of the cathode, and the upper substrate (11) is provided with a cooling working medium inlet channel (112) and a cooling working medium outlet channel (113) which are communicated with the cooling cavity (121).

3. The arc plasma generator according to claim 1, characterized in that the insulating support assembly (2) comprises a top insulating layer (21), a bottom insulating layer (22), a bottom support (23) and a retaining member (24), the top insulating layer (21) being connected with the bottom support (23) by the retaining member (24) to clamp the intermediate member (3), the gas inlet member (4), the insulating member (5) and the anode (6) between the top insulating layer (21) and the bottom support (23), the bottom insulating layer (22) being mounted on the side of the bottom support (23) facing the top insulating layer (21).

4. The arc plasma generator according to claim 1, characterized in that the first plasma channel (31) comprises a gas inlet region (311) and a discharge region (312), both ends of the discharge region (312) are respectively communicated with the gas inlet region (311) and the second plasma channel (61), and the aperture of one end of the gas inlet region (311) close to the discharge region (312) is gradually reduced along the gas inlet direction.

5. The arc plasma generator according to claim 1, wherein the second plasma channel (61) comprises an expansion section (611), a sudden expansion straight cylinder section (612) and a contraction beam section (613) which are sequentially communicated from top to bottom, the caliber of the expansion section (611) is gradually increased along a direction gradually approaching the sudden expansion straight cylinder section (612), the caliber of the sudden expansion straight cylinder section (612) is larger than that of any position of the expansion section (611), a sudden expansion shoulder (614) is formed between the sudden expansion straight cylinder section (611), and the caliber of the contraction beam section (613) is gradually decreased along a direction gradually departing from the sudden expansion straight cylinder section (612).

6. The arc plasma generator according to claim 5, characterized in that an air distribution chamber (7) is formed between the air inlet member (4) and the intermediate member (3), the side wall of the air inlet member (4) is provided with an air inlet channel (41) communicated with the air distribution chamber (7) for introducing the shielding gas, the air inlet member (4) is provided with a first shielding gas channel (42), and two ends of the first shielding gas channel (42) are respectively communicated with the air distribution chamber (7) and one end of the expansion section (611) departing from the cylindrical section (612);

the first shielding gas channel (42) is obliquely arranged, and the axis of the first shielding gas channel (42) is opposite to the axis of the expanding section (611), so that the shielding gas discharged from the first shielding gas channel (42) forms spiral gas flow in the expanding section (611).

7. The arc plasma generator according to claim 6, wherein the air inlet member (4) is further provided with an air inlet hole (43) communicated with the air distribution chamber (7), the insulating member (5) is provided with a vent hole (51), the anode (6) is provided with an air outlet hole (62), the air outlet hole (62) extends from the top surface of the anode (6) to the sudden expansion shoulder (614), and the air inlet hole (43), the vent hole (51) and the air outlet hole (62) are sequentially communicated to form a second shielding gas channel.

8. The arc plasma generator according to claim 7, wherein the exhaust hole (62) is arranged obliquely, and the axis of the exhaust hole (62) is out of plane with the axis of the cylindrical section (612) so that the shielding gas exhausted from the second shielding gas channel forms a spiral gas flow in the cylindrical section (612).

9. The arc plasma generator according to claim 1, further comprising a first cooling sleeve (8) and a second cooling sleeve (9);

the first cooling sleeve (8) is sleeved outside the intermediate piece (3) and forms a first cooling cavity with the intermediate piece (3);

the second cooling sleeve (9) is sleeved outside the anode (6) and forms a second cooling cavity with the anode (6);

the air inlet part (4) is clamped between the first cooling sleeve (8) and the second cooling sleeve (9), and a cooling working medium conducting hole (44) for communicating the first cooling cavity with the second cooling cavity is formed in the air inlet part (4).

10. The arc plasma generator according to claim 9, characterized in that a first cooling channel (32) is arranged in the intermediate member (3), both ends of the first cooling channel are communicated with the first cooling cavity, one end of the first cooling channel (32) is higher than the other end, and the caliber of one end is larger than that of the other end;

and a second cooling channel (63) with two ends communicated with the second cooling cavity is arranged in the anode (6), one end of the second cooling channel (63) is higher than the other end, and the caliber of one end is larger than that of the other end.

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