KR20060126307A - Compact-sized plasma torch with a convenience of mutual conversion between welding and cutting process - Google Patents

Abstract

A plasma torch which can be mutually converted between welding and cutting operations and can generate thermal plasma having characteristics in accordance with respective operation purposes by only exchanging three types of components including a cathode, a nozzle and a shield gas cap that can be simply separated from a body of the torch or clamped to the body thereof is provided. In a plasma torch for generating thermal plasma through transfer type arc discharge, the plasma torch comprises: a cathode comprising a cathode body formed in a rod shape for discharge and a cathode peak connected to an end of the cathode body; a nozzle formed in such a shape that the nozzle covers the cathode with being spaced from the outer periphery of the cathode in a predetermined gap to form a discharge gas passage; and a shield gas cap formed on the outer periphery of the nozzle such that shield gas cap is spaced from the nozzle in a predetermined gap to form a shield gas passage, wherein the cathode, the nozzle and the shield gas cap are separably connected to the plasma torch to enable mutual conversion between welding and cutting operations only through exchange of the foregoing three components.

Description

Compact plasma torch with easy switching between welding and cutting operations {COMPACT-SIZED PLASMA TORCH WITH A CONVENIENCE OF MUTUAL CONVERSION BETWEEN WELDING AND CUTTING PROCESS}

1 is a cross-sectional view of the plasma torch of the case for welding (A) and the case for cutting (B) according to an embodiment of the present invention.

2 is a cross-sectional view of a cathode for a welding operation according to the present invention.

3 is a sectional view of a nozzle for welding operation according to the present invention;

4 is a cross-sectional view of a protective gas cap for a welding operation according to the present invention.

5 is a cross-sectional view of a cathode for cutting operation according to the present invention.

6 is a cross-sectional view of a nozzle for cutting operations in accordance with the present invention.

7 is a cross-sectional view of a protective gas cap for cutting operation according to the present invention.

8 is a plan view of the gas injection ring forming the vortex movement of the discharge gas according to the present invention.

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

1-1a: Cathode Tip for Welding 1-1b: Cathode Tip for Cutting

1-2a: cathode body for welding 1-2b: cathode body for cutting

2a: nozzle for welding 2b: nozzle for cutting

3a: Protective gas cap 3b: Cutting gas cap

4: Cathode Cooling Gas Guide

5-1: Cathode Guide 5-2: Cathode Guide Insulator

6: pilot power guide

7: Torch exterior

8: Pilot power supply

9: Gas injection ring

10-1: guide part insulator 10-2: inlet part insulator

The present invention relates to a compact plasma torch for precisely welding or cutting a metal base metal. The heat plasma generated from a transfer arc discharge is used as a heat source to simultaneously weld the base metal or the base material and a welding rod, and then naturally cool the welding. Cutting is carried out by removing the melt while melting the base material using a thermal plasma jet of. Welding using plasma torch can freely output power by controlling current of power supply, so it is easy to adjust welding input heat, so that thin plate welding is possible, and it can be applied to almost all metal welding. It has the advantage of excellent deformation and low deformation. In addition, the cutting using the plasma torch can also freely adjust the output to minimize damage to the base metal other than the cutting part, can be applied to almost all metals including non-ferrous metals, various kinds of discharge gas can be used, and the cutting speed is high, The cost of manufacturing and operating the equipment is low, and the operation is easy.

Welding and cutting using a plasma torch commonly use thermal plasma by transfer arc discharge as a heat source for melting the base material, but welding generates a relatively wide range of molten base by forming a relatively slow and spatially wide range of thermal plasma. Condition is required to constrain the metal in the melt. Cutting, on the other hand, requires relatively high speed and spatially concentrated thermal plasma to form a narrow melt and remove the melt. As welding and cutting require different thermal plasma characteristics depending on the purpose of operation, plasma torches for welding or cutting have been mainly developed separately from each other. Thus, inefficiency in technology and cost in the manufacture and operation of the device is required. In particular, when the welding and cutting operations have to be alternated in the industrial field, it is inconvenient to change the torch whenever there is a change of work. Therefore, in order to concentrate technology, reduce cost, and ease of operation, a plasma torch that requires welding and cutting at the same time and can easily switch between the two operations is required.

In order to solve the above problems, as shown in Figure 1, the connection is made of threaded thread, so that only the three parts of the cathode, nozzle, protective gas cap is easy to remove and tighten from the torch body, welding and cutting operations It is possible to convert each other and to generate thermal plasma with characteristics suitable for each work purpose.

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

Removable welding cathodes 1-1a, 1-2a, nozzles 2a, and protective gas caps 3a;

Detachable cutting cathodes 1-1b, 1-2b, nozzles 2b, and protective gas caps 3b;

A cathode guide 5-1 coupled to the cathode to serve as a path for arc current;

A pilot power guide (6) coupled to the nozzle and serving as a path for a high frequency high voltage power supply for initial discharge during cutting;

A torch enclosure 7 coupled with the protective gas cap;

Cathode cooling gas guide (4), which allows the protective gas to cool the cathode body (1-2a, 1-2b) and the cathode guide (5-1), receives the pilot power from the power supply and delivers to the pilot power guide The pilot power introduction body 8 into which the discharge gas is injected, the gas injection ring 9 forming the vortex movement of the discharge gas, and the negative electrode which prevents abnormal discharge between the pilot power guide 6 and the negative electrode guide 5-1. A torch composed of a guide insulator 5-2, a guide part insulator 10-1, and an inlet part insulator 10-2 is provided.

In particular, the plasma torch

A negative electrode having a negative electrode body formed in a rod shape for discharging and a negative electrode peak coupled to an end of the negative electrode body;

A nozzle formed to surround the cathode at a predetermined interval on the outer circumference of the cathode to form a discharge gas passage;

The protective gas cap formed at a predetermined interval on the outer circumference of the nozzle to form a protective gas passage may be coupled / separated from the plasma torch.

For welding work with the plasma torch

The cathode peak is formed of a conical tungsten material

The end of the nozzle is formed of a ceramic material above the cathode

The protective gas cap may be formed above the nozzle to generate a slow spatially wide thermal plasma.

For cutting with the plasma torch

The cathode peak is formed of a hafnium material of a flat shape

The nozzle completely surrounds the cathode, and the outlet is formed of a metal material below the cathode.

The end of the protective gas cap may be formed below the outlet of the nozzle to generate a high speed spatially concentrated thermal plasma.

The inside diameter of the outlet side of the nozzle is 1.5 mm or more, preferably about 2 mm.

The plasma torch has a gas injection ring having a plurality of holes inclined at predetermined angles at equal intervals in the circumferential direction so as to further expand the spatial distribution of thermal plasma and to stabilize the arc movement during cutting. 6) may be arranged on the top of the nozzle to increase the vortex movement of the gas injected into the gas injection ring.

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

1 is a cross-sectional view of a plasma torch of the case for welding (A) and the case for cutting (B) according to an embodiment of the present invention, wherein each plasma torch is a cathode which is a component to be replaced according to the working purpose of welding and cutting , The torch head portion where the nozzle and the protective gas cap are located, the pilot power inlet (8) that receives the discharge gas and the pilot power when cutting, and the discharge gas and the protection gas are separated from each other without being mixed with each other to flow inside the torch. A flow path is formed so that the passage compartment of the discharge gas is provided with an insulator 10-2 and an pilot insulator 10-2 for suppressing abnormal discharge between the pilot power introducer 8 and the cathode guide 5-1. While injecting into the nozzle while forming a vortex movement of the guide insulator 10-1 for suppressing abnormal discharge between the pilot power guide 6 and the negative electrode guide 5-1 and the discharge gas flowing along the passage The gas injection ring (9) to be injected, the protective gas injected to the cathode body (1-2a, 1-2b) after cooling the cathode gas flow guide to cool the flow through the wall of the cathode guide (5-1) ( 4), the negative electrode guide 5-1 combined with the negative electrode to serve as a path for the arc current and serve as a passage of the protective gas together with the guide insulator 10-1, and an insulator 10- 10 for the flow of the protective gas. 2) serves as the final path of the negative electrode guide insulator (5-2) and the protective gas to suppress abnormal discharge of the negative electrode guide (5-1) and the pilot power inlet (8) that can be generated through the hole in the It consists of the torch body of the torch sheath (7) coupled with the protective gas cap. Pilot power guide coupled with the negative electrode guide (5-1), the welding nozzle (2a) or the cutting nozzle (2b) coupled to the welding cathode body (1-2a) or the cutting cathode body (1-2b) ( 6), the torch sheath 7 which is combined with the welding protective gas cap 3a or the cutting protective gas cap 3b has a screw groove at the connection portion to facilitate fastening and detachment of replacement parts according to the purpose of work. .

In order to generate thermal plasma having characteristics required for the purpose of welding and cutting, as shown in Fig. 1A, the diameter of the welding nozzle 2a is larger than that of the cutting nozzle 2b for the welding operation. It is widened, and its position is placed on top of the cathode body (1-2a) so that the discharge gas supplied to the nozzle is extended along the outer edge of the arc formed between the cathode tip and the base material. It can be generated. In addition, as shown in FIG. 1B, in the case of cutting, the diameter of the cutting nozzle 2b is narrower than that of the welding nozzle 2a and the length thereof is increased, and the position of the nozzle outlet from the cathode tip 1-1b. It was placed at the lower end to a certain distance, so that the discharge gas exited the nozzle while contracting the arc, so that a high-speed and spatially concentrated thermal plasma could be generated on the surface of the base material. In particular, in this case, as shown in FIG. 8, six flow path holes in the gas injection ring 6 are inclined at a predetermined angle to increase the vortex movement of the discharge gas, and during discharge, the discharge gas exits the nozzle and moves outward from the arc. It expands the spatial distribution of thermal plasma, and when cutting, the discharge gas wraps around the arc column to reduce the pressure around the discharge axis, thereby smoothing the arc formation and stabilizing the movement of the arc. To make it work.

2 is a cross-sectional view of a welding cathode in which a welding cathode tip 1-1 a and a cathode body 1-2 are combined; In the welding operation, the arc movement is unstable because the flow of the discharge gas surrounding the arc pillar is formed outwardly about the discharge center axis to form a wide thermal plasma region. Therefore, the distance between the tip of the negative electrode tip, which is the discharge interval, and the base material connected to the positive electrode is relatively close to about 2 mm, and since there is often no separate pilot circuit for initial discharge, a smooth initial discharge can be achieved. The negative electrode tip 1-1a for welding was made conical so that it might be possible. In addition, the welding cathode tip (1-1a) is made of tungsten, which has a high melting point because it is in contact with a high temperature thermal plasma region. (1-2a) was made of oxygen-free copper with good heat transfer. In addition, Figure 5 shows a cross-sectional view of the cutting negative electrode combined with the cutting negative electrode tip (1-1b) and the negative electrode body (1-2b), similar to the welding negative electrode to increase the cooling efficiency to increase the lifetime of the electrode oxygen-free The cutting cathode body (1-2b) made of the same material is used. In the case of the cutting cathode tip (1-1b), various kinds of discharge gases are used during cutting operation. Since the air may be used, the negative electrode tip may be used even in an oxygen atmosphere. Hafnium material was used to play a role.

FIG. 3 shows a sectional view of the welding nozzle 2a having an inner diameter (8 mm) wider than the cutting nozzle 2b having an outlet inner diameter of 2 mm shown in FIG. 6. While the diameter of the portion where the welding nozzle 2a and the pilot power guide 6 are coupled is 15 mm, the length of the portion is shortened to 5 mm, so that the spacing of the threads is narrowed to 1 mm so that the coupling force is strong. The cutting nozzle 2b was also coupled to the pilot power supply guide 6 in the same manner as the welding nozzle 2a, and the distance was equally set to 1 mm so that the coupling force by the thread was strong. In the case of the welding nozzle (2a) is exposed to the outside of the torch, the welding work is not necessary because a separate pilot circuit for the initial discharge, the ceramic material was used in consideration of the safety of the operator. On the other hand, the cutting nozzle 2b is hidden inside the torch by the cutting protection gas cap 3b, so that there is no risk of electric shock to the operator, and the distance between the negative electrode peak and the base material connected to the positive power supply is 10 mm or more during cutting. Because it is far away, it is necessary to use a pilot circuit for initial discharge, so a metal material is used. The smaller the inner diameter of the cutting nozzle (2b) is advantageous to generate a high-speed thermal plasma, but if the inner diameter is too small (1.5 mm or less), the discharge gas may be excessively contracted by the arc column, the discharge can be stopped, so the inner diameter is 2 mm.

Figure 4 shows a cross-sectional view of the welding protective gas cap (3a), the same as the welding nozzle (2a) because the appearance is to the outside of the torch, using a ceramic material in consideration of the safety of the operator, the torch sheath (7) and The diameter of the part to be joined is 19 mm, while the length thereof is short as 5 mm, so that the thread spacing is 1 mm in order to secure a sufficient coupling force when tightening. The molten melted by the thermal plasma is easily oxidized when it comes into contact with air due to the characteristics of high temperature, but when the oxidation occurs during welding, the bonding force of the weld is reduced, so that the welding protective gas cap 3a and the welding nozzle ( The protective gas that escapes between 2a) and the discharge gas serves to prevent oxidation of the molten pool.

7 shows a cross-sectional view of the cutting protective gas cap 3b. Like the protective gas cap 3a for welding, the shape is revealed outside the torch, and a ceramic material is used in consideration of the safety of the operator. ) And the diameter of the combined part is 19 mm, while the length is short as 5 mm, the thread spacing was set to 1 mm in order to ensure a sufficient coupling force when tightening. As shown in Fig. 1B, the exit face of the cutting protection gas cap 3b is located slightly below (0.5 mm) the exit surface of the cutting nozzle 2b, which is a cutting protection gas cap 3b. The exit gas and the exit surface are further contracted by a protective gas that escapes between the cutting nozzles 2b to surround the thermal plasma jet, thereby generating a more spatially contracted thermal plasma jet, thereby narrowing the cutting width. This is to prevent the deformation of the base material due to the sudden temperature difference that may occur in the local area during the cutting operation due to the protection gas reaching between the cutting part and the outer area where the cutting takes place.

Plasma torch according to the present invention generates a thermal plasma by a transfer arc discharge to weld or cut the metal base material, the three parts of the cathode, the nozzle, the protective gas cap is screwed to the head of the torch It is possible to switch between the two operations by replacing them, and to generate thermal plasma with characteristics suitable for each application purpose, making it easy to manufacture and maintain the torch when both welding and cutting operations are required. It is effective in improving the economics in the world.

Claims (5)

In the plasma torch that generates thermal plasma through a transfer arc discharge, A negative electrode comprising a negative electrode body formed in a rod shape and a negative electrode peak coupled to an end of the negative electrode body for discharge; A nozzle formed to surround the cathode at a predetermined interval on the outer circumference of the cathode to form a discharge gas passage; The protective gas cap which is formed at the outer circumference of the nozzle at a predetermined interval to form a protective gas passage is coupled / separated from the plasma torch. Plasma torch, characterized in that the switching between the welding operation and the cutting operation only by replacing the three parts The method of claim 1, wherein the plasma torch is used for welding. The cathode peak is formed of a conical tungsten material The end of the nozzle is formed of a ceramic material above the cathode And the protective gas cap is formed above the nozzle to generate a slow spatially wide thermal plasma. The method of claim 1, wherein the plasma torch is used for the cutting operation. The cathode peak is formed of a hafnium material of a flat shape The nozzle completely surrounds the cathode, and the outlet is formed of a metal material below the cathode. And the distal end of the protective gas cap is formed further below the outlet of the nozzle to generate a high speed spatially concentrated thermal plasma. 4. A plasma torch as claimed in claim 3, wherein the outlet inner diameter of the nozzle is at least 1.5 mm and preferably at or about 2 mm. The plasma torch according to claim 2 or 3, wherein the plasma torch has a predetermined angle at equal intervals in the circumferential direction in order to further expand the distribution of spatial thermal plasma during welding and to stabilize the movement of the arc during cutting. Gas injection ring 6 having a plurality of holes inclinedly disposed on the top of the nozzle to increase the vortex movement of the gas injected into the gas injection ring, and the arrangement of the cathode, the nozzle and the protective gas cap Plasma torch, characterized in that different depending on the welding operation and the cutting operation.

Images