JPH034445Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes a first passage formed between a cathode rod and a mantle surrounding the cathode rod through which an inert gas can flow;
The present invention relates to an apparatus including a plasma arc torch having at least a second passageway through which an active gas can flow, which is disposed outwardly of the passageway of the plasma arc torch.

[Conventional technology]

Conventionally, a good method for cutting workpiece materials such as metals using a plasma arc torch, for example,
An inert gas such as argon is supplied as a protective gas to the first passage 3 formed between the cathode rod 1 and the first mantle 2 in the torch body T as shown in FIG.
A predetermined amount of G _N is flowed, and an active gas G _A such as oxygen gas is flowed as a plasma gas into the second passage 5 formed between the first mantle 2 and the second mantle 4. Then, the cathode rod 1 and the workpiece material 6
There is a method in which the workpiece material 6 is cut by a plasma arc column 7 formed between the two. In this case, the minimum flow rate of the inert gas G _N must be such that the active gas G _A does not enter the first passage 3 formed by the cathode rod 1 and the first jacket 2 . Note that 8 is a DC power source connected between the cathode rod 1 and the workpiece material 6 with the polarity shown.

[Problem that the invention attempts to solve]

However, in order to perform high-quality cutting on steel plates, etc., it is desirable to reduce the amount of the inert gas G _N sufficiently, but if the inert gas G _N is lower than the above minimum flow rate, the pressure of the active gas G _A will increase. As a result, a large amount of the gas enters the first passage 3 and instantly damages the cathode rod 1. In other words, when the workpiece material 6 is cut by the plasma arc column 7, the cathode rod 1, which is a tungsten electrode, is heated to almost the melting point temperature, so when it comes into contact with active gas, it is instantly oxidized and consumed. It is. Therefore, in the conventional device, a certain amount of protective gas has to be flowed into the first passage 3 with sufficient margin to prevent the plasma gas from entering the first passage 3, and for this reason, the cutting material In some cases, it is not always possible to obtain high-quality cutting performance, and furthermore, the flow rate of the inert gas G _N is large, making it uneconomical. Even with this consideration, there is a limit to the flow rate of inert gas that can be flowed due to cutting performance, so fluctuations in the arc current during cutting may increase the pressure in the plasma gas passage. , the active gas may enter the first passage 3 and cause the cathode rod 1 to wear out.

[Means for solving problems]

In order to eliminate the above-mentioned drawbacks, the present invention provides a first passage formed between a cathode rod and a mantle surrounding the cathode rod through which an inert gas can flow, and an active conductor disposed outwardly of the first passage. In an apparatus equipped with a plasma arc torch having at least a second passage through which gas can flow, an electrode protecting insulator having a through hole or having a through hole formed between the first passage and the first passage is used. The present invention provides a plasma arc device that is fitted into a passageway of a plasma arc device.

[Effect]

This invention has the above structure, so
When the inert gas flows through the through hole and this through hole becomes the first passage, the volume of the first passage becomes extremely small, and the pressure of the inert gas in the first passage increases. Therefore, even if the flow rate of the inert gas is lower than the conventional one, the active gas will not flow into the first passage.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention. In the figure, a cylindrical electrode protection insulator 9 whose outer side is approximately square is fitted into the first passage 3 of the torch body T, which is a passage for the inert gas G _N. For this reason, the inert gas G _N flow path in the part of the first passage 3 where the electrode protection insulator 9 is fitted has a width that is formed by the electrode protection insulator 9 and the first jacket. There are only four narrow through holes, and the first hole of the torch body T
The volume of the passage 3 becomes extremely small. This increases the pressure of the inert gas in the first passage and prevents _the active gas G _A from flowing into the first passage 3. It is possible to prevent the cathode rod 1 from being worn out due to the inflow into the inside of the cathode rod 3. Furthermore, even if the flow rate of the inert gas is lower than the conventional one, the active gas will not flow into the first passage, and the required amount of inert gas can be reduced compared to the conventional one, so that the processing surface of the workpiece material 6 can be improved. Excellent and economical effects can be obtained. Note that the volume of the first passage 3 is made extremely small to increase the pressure of the inert gas in the first passage 3 to prevent the active gas from flowing into the first passage 3, and the cathode The electrode protection insulator 9 that protects the rod 1 is the cathode rod 1 and the first mantle 2.
Since both are conductors, they must be insulators.

FIG. 3 is a diagram showing another embodiment of the present invention. In the figure, a cylindrical electrode protection insulator 9 having four holes 10 passing therethrough is fitted into a first passage 3 of the torch body T, which is a flow path for an inert gas G _N. Therefore, the flow path for the inert gas G _N in the portion of the first passage 3 where the electrode protection insulator 9 is fitted is only the through hole 10, and the volume of the first passage 3 of the torch body T is becomes extremely small. In this embodiment as well, substantially the same effects as in the embodiment shown in FIG. 1 can be obtained.

[Effect of idea]

As described above, the present invention includes a first passage formed between a cathode rod and a mantle surrounding the cathode rod through which an inert gas can flow, and an active gas passage arranged outwardly of the first passage. In an apparatus equipped with a plasma arc torch having at least a second passageway, an electrode protection insulator having a through hole or having a through hole formed between the first passageway and the first passageway. This is a plasma arc device characterized by being fitted into a. Since the present invention has such characteristics, the inert gas flows through the through hole, and this through hole becomes the first passage.
Since the volume of the passage becomes extremely small and the pressure of the inert gas in the first passage increases, active gas will not flow into the first passage even if the flow rate of the inert gas is lower than before. There is no. Therefore, not only is it possible to prevent wear and tear on the cathode rod due to the inflow of active gas into the first passage, but also the required amount of inert gas can be reduced compared to the conventional method, resulting in an excellent machining surface of the workpiece material and an economical method. The effect is obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing a conventional plasma arc device, and FIG. 3 is a diagram showing another embodiment of the present invention. 1... Cathode rod, 2... First cloak, 3... First
passage, 4... second cloak, 5... second passage,
6... Material to be processed, 7... Plasma arc column, 8
...DC power supply, 9... Insulator for electrode protection, 10...
...through hole.

Claims (1)

[Claims for Utility Model Registration] A first passage formed between a cathode rod and a mantle surrounding the cathode rod through which an inert gas can flow, and an active gas disposed outwardly of the first passage through which an inert gas can flow. In an apparatus equipped with a plasma arc torch having at least a second passage, an electrode protecting insulator having a through hole or having a through hole formed between the first passage and the first passage is provided.
A plasma arc device characterized by being fitted into a passageway of.