KR100631820B1 - Modularized nontransferred thermal plasma torch with an adjustable structure for material processing - Google Patents

Abstract

The present invention relates to the design and fabrication of a plasma torch that generates thermal plasma that can be applied to material processes such as new material synthesis, surface treatment of materials, and plasma spraying. The modular design of the components allows for longer torch life and improved torch thermal efficiency, enables the use of reactive gases as arc gases, and freely deforms the anode nozzle, a key component of the plasma torch, depending on the intended application. The present invention relates to the development of a rod-nozzle type DC non-feeding plasma torch that is modularized so that it can be used for structural change.

Description

MODULARIZED NONTRANSFERRED THERMAL PLASMA TORCH WITH AN ADJUSTABLE STRUCTURE FOR MATERIAL PROCESSING}

1 is a cross-sectional view of a thermal plasma torch in accordance with an embodiment of the present invention.

2 is a cross-sectional view of a cathode and an anode structure of a thermal plasma torch according to an embodiment of the present invention.

Figure 3 is a cross-sectional view of the gas injection portion of the thermal plasma torch according to an embodiment of the present invention

4 is a view showing the flow path of the cooling water and the injection path of the arc gas in the thermal plasma torch according to an embodiment of the present invention.

Figure 5 is a cross-sectional view of the modular design of the internal and external anode cooling cooling water line of the rod-nozzle type non-feeding thermal plasma torch for the material processing according to an embodiment of the present invention

Figure 6 is an illustration of a plasma torch modified to an argon plasma torch in accordance with an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: cathode support 2: cathode coolant guide

3: cathode body 4: cathode peak

5: inner anode 6: outer pole

7: Cathode Gas Guide 8: Cathode Gas Injection Ring

9: Body coolant guide 10: Anode coolant guide I

11: Positive anode coolant guide II 12: Insulation gap

13: Anode gas injection ring 14: Anode coolant guide I

15: Anode coolant guide II 16: Anode coolant guide III

17: cathode insulation sheath 18: gas injection sheath

19: pilot electrode sheath 20: insulation gap sheath

21: anode exterior 22: anode lid

As the industrial society becomes more advanced, more functional materials are required to be manufactured, and there is a limit to the material processing method using a flame by burning natural gas or liquefied gas based on existing fossil fuels. Plasma jet flames generated by a thermal plasma torch use electricity and gas, making it easier to control operating conditions, less pollution, smaller equipment, and very high temperatures and calories than conventional fossil fuels. It is expected to be a new means to overcome this limitation.

However, the conventional rod nozzle type DC non-feed thermal plasma torch, which is widely used for the current material process, uses a cathode made of tungsten, and when a hydrocarbon-based reactive gas such as oxygen or methane is used as the arc gas, As tungsten, which is a cathode material, is oxidized, erosion of the cathode is greatly increased, thereby shortening electrode life, and it is difficult to maintain an arc because hot electron emission is suppressed.

In addition, the thermal plasma torch has to be high power in order to process a large amount of material. If the operating current is increased to obtain a high power, the electrode erosion becomes large and the electrode must be replaced frequently. In order to prevent this, it is required to obtain a high output by increasing the operating voltage even at a low current. At this time, as a method for increasing the operating voltage, there is a method of using a gas having a large discharge voltage as the arc gas, or increasing the length of the arc. For this purpose, when changing the arc gas or increasing the arc length, an electrode structure suitable for each arc gas or an electrode structure suitable for extending the arc length is required. Therefore, a design change of the electrode structure is required. The problem is that the overall design of the torch must be changed.

In the case of the thermal plasma torch for the material process, since the required plasma characteristics are different according to the respective application purposes to be applied, an electrode optimized for each application purpose should be used. For example, plasma spraying requires high temperature and high flow rate plasma, while new material synthesis and surface treatment require plasma having a high temperature section and a uniform temperature distribution. Therefore, a thermal plasma torch for a material processing process having an anode nozzle having a small diameter for plasma spraying and an anode nozzle having a large diameter for new material synthesis and surface treatment is required.

In conclusion, in order to solve the above-mentioned problems, various arc gases including reactive gases can be used, and high power can be operated even at low current, and the electrode structure can be easily changed according to each application purpose to be applied. There is a need for thermal plasma torches for modular processing of torch components.

The present invention is to solve the conventional problems as described above, an object of the present invention is to use a reactive gas such as oxygen, methane as an arc gas, it is possible to operate a high power at low current as well as increase the operating life In addition, the modular design of each component provides a thermal plasma torch for the material processing process, which is easy to change the electrode structure and reduces the time and cost required for fabrication.

In order to achieve the above object, the present invention is designed to improve the structure of the electrode, the gas injection method and modularize the torch components. By improving the structure of the electrode, the length of arc generated under the same operating condition is increased than before, and the high arc voltage appears at low current, enabling low current and high power operation, thereby reducing the erosion rate of the electrode and reducing the lifetime of the torch. Increased. In addition, the gas injection method was improved to directly inject a reactive gas such as oxygen or methane into the plasma without damaging the tungsten cathode during the material process, thereby enhancing the function as a torch for the material process. In addition, by modularizing the components of the torch, it is easy to change the design of the plasma torch by easily accommodating it when the electrode structure is changed to suit each application purpose. Therefore, by reducing the time and cost required for the optimal design and fabrication of the plasma torch according to the respective application purposes, it is possible to produce a high-performance material economical using this.

In order to achieve the object as described above, the present invention

A negative electrode composed of a negative electrode body 3 and a negative electrode peak 4;

A thermal plasma torch is produced by reacting with the cathode to generate a thermal plasma, the anode comprising an anode divided into an inner anode 5 and an outer anode 6 by an insulating gap 12.

The thermal plasma torch has a cathode gas injection ring 8 at the rear of the cathode, and an anode gas injection ring 13 at the front of the insulating gap 12 to provide two arc gas injections. It may be a thermal plasma torch possible from the above.

In the thermal plasma torch, the cathode / anode gas injection rings 8 and 13 may include a plurality of holes inclined at predetermined angles at equal intervals along the circumferential direction.

In the thermal plasma torch, the negative electrode body 3 is made of oxygen-free copper, the negative electrode peak 4 is tungsten, and the inner positive electrode 5 and the outer positive electrode 6 may each be made of oxygen free copper.

In the thermal plasma torch, the distance between the cathode and the anode 5 and 6 may be 1 mm to 2 mm, and the distance between the inner anode 5 and the outer cathode 6 may be 2 mm to 5 mm.

The thermal plasma torch may further include a coolant passage formed in a single line to cool the cathode and the inner / outer cathodes 5 and 6.

In the thermal plasma torch, the component parts of the plasma torch may be modularized so that each or a combination of parts thereof may be replaced. Replaceable parts include the sheath 17, 18, 19, 20, 21, the coolant lines 10, 11, 14, 15, 16 and the gas supply lines 7, 8, 9, 12, 13. do.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a thermal plasma torch according to the present invention, which has a rod-nozzle type electrode structure, and has an inner positive electrode 5 formed by a cathode and an insulating gap 12 made of oxygen-free copper and yttrium added tungsten. ) And anode (6), and has a structure having a cathode gas injection ring (8) and anode gas injection ring (13) for injecting the arc gas to vortex movement to stabilize the arc have. In addition, the negative electrode support (1) for supplying the negative power (-) and the cooling water, the negative electrode insulating sheath (17) for fixing the same, and the negative electrode coolant guide for increasing the cooling efficiency by increasing the flow rate by reducing the flow path of the cooling water ( 2), a cathode gas guide 7 made of an insulator was installed to insulate the cathode and anode 5, 6 and serve as a path of the arc gas. The flow path of the coolant for cooling the cathode and the inner / outer anodes (5,6) includes the body coolant guide (9) and the inner anode coolant guides I, II (10,11), the insulating gap body (12), and the outer cathode coolant guide. It consisted of I, II, III (14, 15, 16). The inert arc gas is injected from the gas injection sheath 18 and supplied to the cathode gas injection ring 8 via the body coolant guide 9, and the reactive gas injected through the insulation gap sheath 20 is formed into an insulating gap body ( 12) was injected into the anode gas injection ring 13 to allow the arc gas to be used without damaging the tungsten cathode. Cathode insulating sheath 17 for fixing the cathode support 1, gas injection sheath 18 for supplying inert gas, pilot electrode sheath 19 for pilot power supply, insulation gap for supplying reactive gas The exterior 20, the positive power supply (+) and the positive electrode sheath 21, which serves as the outlet of the cooling water and the positive electrode lid 22, which serves as a power passage for the outer anode 6, perform each function, It wraps inside the torch and finishes the exterior.

Here, the cathode support 1 is made of a screw groove on the inside of the left end so that it is easy to receive negative power (-) and cooling water at the same time, and a cathode groove by making a screw groove on the inside and the outside of the right end (2). ) And the negative electrode body (3) were to be coupled by a thread. The negative electrode insulating sheath 17 has four bolt holes, which are connected to the gas injection sheath 18 to fix the negative electrode support 1. The gas injection sheath 18, the pilot electrode sheath 19, the insulation gap sheath 20, the anode sheath 21 and the anode lid 22 were connected to each other through screw grooves made in each. Each component in the interior of the torch was equipped with a working jaw for easy alignment during disassembly and assembly of the torch, and these aligned internal components were pressed and fixed with the anode lid 22.

2 is a cross-sectional view showing the structure of the cathode and the anode of the thermal plasma torch according to the present invention. In order to facilitate the initial discharge of the arc, the spacings 25 and 26 of the closest portions of the cathode peak 4 and the inner anode 5 were maintained at 1 mm to 2 mm. In addition, when the distance between the cathode surface 23 and the anode surface 24 is similar to or smaller than the distance between the closest portions 25 and 26, an initial discharge is generated at the cathode surface 23 and the anode surface 24 so that the cathode may be negative. Since the body 3 may be damaged or even the cathode gas injection ring 8 may be damaged, the angle between the central axis is 21 ° at the cathode surface 23 and 23 ° at the anode surface 24. By processing, the gap between the cathode and the anode is wide near the cathode gas injection ring (8) and processed to be narrower toward the cathode peak (4) to prevent this. The anode was divided into the inner anode 5 and the outer anode 6 by the insulating gap 12 and manufactured with the same diameter so as not to interfere with the flow of the arc gas. In order to easily transition the arc generated in the anode (5) to the outer anode (6) was made of 2 mm ~ 5 mm.

3 is a cross-sectional view of the gas injection unit of the thermal plasma torch according to the present invention. The cathode gas injection ring 8 is compressed and fixed by the cathode gas guide 7 and the body coolant guide 9 at the rear of the cathode as shown in FIG. 1, and the anode gas injection ring 13 is formed by the inner anode 5 and the cathode. The outer and outer anodes 6 are fixed by the inner and outer anodes 5 and 6 and the insulating gap 12. In addition, as the material used, the cathode gas injection ring 8 is made of brass, which can be used even in a high temperature environment and has excellent workability. The anode gas injection ring 13 must electrically insulate between two anodes. The radiant heat of the generated arc should not be damaged, so it was manufactured using a workable ceramic. The arc gas is such that an inert gas such as nitrogen is passed through the cathode gas injection ring 8 so that the cathode is not damaged due to the reaction between the reactive gas and the negative electrode 4 made of tungsten containing yttrium, thereby generating an initial arc discharge. Through the anode gas injection ring 13, reactive gases such as methane and oxygen can be distinguished and injected. In addition, six small holes, which were drilled at an angle, were drilled in the cathode / anode gas injection rings 8 and 13 to inject the arc gas more evenly between the electrodes.

FIG. 4 illustrates a path through which coolant flows and an arc gas between the two electrodes to cool the components of the torch such as the cathodes 3 and 4 and the anodes 5 and 6 by the heat of the arc plasma generated inside the electrode. The injection path is shown. The coolant supplied to the cathode support 1 cools the cathodes 3 and 4 while flowing through the inner wall of the cathode body 3 through the cathode coolant guide 2, and then opens six oblique holes drilled in the cathode support 1. It exits and comes out again through ten holes vertically drilled on the wall of the cathode gas guide 7. The coolant then passes through 12 holes drilled in the trunk coolant guide 9 and then cools the inner wall of the inner positive electrode 5 while flowing along the flow path made by the inner / positive coolant guides I, II (10, 11). Thereafter, the inner wall of the outer anode 6 was cooled by flowing through the 16 insulating holes 12 and having flowed along the flow path formed by the outer cathode cooling water guides I, II, III (14, 15, 16). Next, it is discharged through the anode sheath 21.

Arc gas can be injected in different ways depending on inert gas such as argon and nitrogen and reactive gas such as methane and oxygen. Inert gas is injected through a hole drilled in the gas injection shell 18 and collected in the groove of the cathode gas guide 7 through 12 holes drilled in a direction perpendicular to the body cooling water guide 9. The gas collected in the groove reaches the cathode gas injection ring 8 through 12 slots dug into the surface of the cathode gas guide 7 and then into the plasma through six small holes obliquely drilled in the cathode gas injection ring 8. Is injected. On the other hand, in the case of the reactive gas, the anode gas injection ring 13 and the insulation gap 12 are injected into the hole formed in the insulation gap body 20 and then radially drilled into the insulation gap 12. Are gathered in an empty space surrounded by). Then, like the cathode gas injection ring 8, reactive gas may be injected into the plasma through the six small holes that are obliquely drilled in the anode injection ring 13.

5 is a cross-sectional view of the modular design of the internal / external anode cooling coolant line of the rod-nozzle type non-feed thermal plasma torch for a material processing according to an embodiment of the present invention. In order to apply the plasma torch for different application purposes, the electrode diameter, length, etc. should be changed and optimized according to the application purpose. In the case of the conventional plasma torch, the design of all components of the torch has to be changed even though the design of the electrode is changed, but the plasma torch according to the present invention is designed in a modular manner, thereby changing the electrode design such as the diameter and length of the electrode. Minimized replacement parts can also be used. As shown in FIG. 1, the torch's sheath is classified according to its function into a cathode insulation sheath 17, a gas injection sheath 18, a pilot electrode sheath 19, an insulation gap sheath 20, and a cathode sheath 21. They were modularized together and machined to thread through each component. As shown in FIG. 5, the cooling water line is modularly divided into inner cathode cooling water guides I and II (10 and 11), an insulating gap body 12, and an outer cathode cooling water guides I, II and III (14, 15 and 16). It was. For example, in the case of using the plasma torch according to the present invention, in the case of the application where the length of the outer anode 6 should be small, as in the case of the conventional plasma torch, the outer electrode 6 and the outer anode simply need not be manufactured again. Only the coolant guide II (15) and the anode shell (21) can be replaced.

6 shows an example in which the plasma torch according to the present invention is changed to the plasma torch for argon. In the case of the argon plasma torch, one electrode 29 is provided without an electrode divided into an inner anode and an outer anode, and a pilot electrode is not required because there is no inner anode. As a result, the coolant line must also be adapted to the changed design. In this case, unlike the conventional plasma torch, which requires redesign of both exterior and internal parts, only a few parts need to be replaced because the present invention is designed to be modular. Remove the pilot sheath 19 and the insulation gap sheath 20 which are not necessary for the function of the argon plasma torch, and redesign the anode sheath 21 for the argon plasma torch so that the anode sheath 31 for the argon plasma is possible. Replace with After that, the coolant guides I and II (10 and 11), the insulating gap body 12, and the anode base injection ring 13, which are not necessary in the cooling line, are removed, and the outer cathode coolant guide II (15) is used for the plasma Replace with Anode Coolant Guide II (30). In addition, the internal and external anodes 5 and 6 are replaced with the argon plasma anode 29. This makes it possible to easily change the use of the plasma torch.

While the invention has been described above with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made within the teachings and appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense of the invention as described in the claims.

According to the present invention, by designing an insulating gap in the middle of the anode nozzle and separating the anode into two parts, a high arc voltage can be obtained under the same operating conditions, thereby enabling high output operation even at a low current. As a result, by reducing the erosion rate of the electrode, it is possible to increase the operating life of the torch even under high power and to manufacture a long-life plasma torch capable of processing a large-scale material. In addition, the gas injection method is improved by injecting reactive gases such as oxygen and methane through the insulating gap, thereby shortening the process time by increasing the density of the reactor in the plasma without damaging tungsten, which is a cathode material, and reducing the production cost. Can be lowered. In addition, by designing the torch components such as exterior, cooling water line, gas supply line by modular design, it is easy to change the assembly to the electrode structure optimized for each application purpose. Economical production of high performance materials is possible with reduced time and cost.

Claims (7)

In a plasma torch that generates thermal plasma, A negative electrode composed of a negative electrode body 3 and a negative electrode peak 4; Reacts with the cathode to generate a thermal plasma, and includes a cylindrical anode divided into an inner anode (5) and an outer anode (6) by the insulating gap 12, the inner anode is located on the cathode body side, A cathode gas injection ring 8 is provided at the rear of the cathode and at the end of the gap between the cathode and the anode, and an anode gas injection ring 13 is provided in front of the insulating gap 12 to provide the arc gas. Injection is possible in two places, and the cathode / anode gas injection rings 8 and 13 include a plurality of holes which are inclined at a predetermined angle at equal intervals along the circumferential direction, The gap between the cathode and the anode is wide near the cathode gas injection ring and narrows toward the cathode attachment portion. After circulating the flow path of the cathode to cool the cathode and the inner / outer anode (5,6), characterized in that formed in a single line to sequentially cool the inner cathode, insulating gap, outer cathode, Thermal plasma torch. delete delete 2. The thermal plasma of claim 1, wherein the cathode body 3 is made of oxygen-free copper, the cathode peak 4 is tungsten, and the inner anode 5 and the outer cathode 6 are each made of oxygen-free copper. torch. The method according to claim 1, wherein the distance between the cathode and the anode 5, 6 is 1 mm to 2 mm, and the distance between the inner anode 5 and the outer cathode 6 is 2 mm to 5 mm. Thermal plasma torch. delete The method according to any one of claims 1, 4 and 5, The component of the plasma torch is modular, the thermal plasma torch of which each or a combination of parts thereof is replaceable.

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