JPH1158021A - Plasma cutting torch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a torch body from being burnedout by arranging a bypass hole to a cooling pipe in the torch body and forming a route to branch a cooling liquid to a cooling liquid return route from a cooling pipe so as to eliminate shutting off of a cooling liquid due to boiling of a cooling liquid and burnout of an electrode. SOLUTION: A cooling passage 5 circulating a cooling liquid in an electrode 2 is arranged in a torch, a bypass hole 6 is arranged to a cooling pipe 3 in the torch body 1, a route, which branches a cooling liquid from a cooling pipe 3 to a cooling liquid return route 4, is formed. In this constitution, when the cooling liquid passage 5 in the electrode 2 is shut off, the burnout of the torch body 1 except the cooling pipe 3 is avoided by a cooling liquid passing the bypass hole 6. Further, by arranging a cooling pipe II7 in the electrode 2, the burnout of the cooling pipe 3 in the torch body 1 is prevented at the time of boiling of cooling liquid or the burnout of the electrode 2. A total cross sectional area of the bypass hole 6 is preferably is >=1/3 to a cross sectional area of the cooling pie 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma cutting torch using a cooling liquid for cooling a torch body and electrodes.

[0002]

2. Description of the Related Art A conventional plasma cutting apparatus using a cooling liquid will be described with reference to FIGS. 3, 4 and 5. FIG. In FIG.
20 is a plasma cutting torch, 21 is a compressor for compressing the working gas and sending it to the plasma cutting torch, 22 is a regulator for adjusting the secondary pressure of the working gas to a constant value, and 23 is a cutting for supplying a current to the plasma cutting torch 20 Power supply,
Reference numeral 24 denotes an installation cable for connecting the base material 25 and the cutting power source 23, and reference numeral 26 denotes a water absorption pump.

[0003] From the cutting power source 23, a drain hose 31 having a built-in conductive wire for draining cooling water, a water supply hose 32 for sending cooling water to the torch, a gas hose 33 for sending operating gas, and an arc start The cable of the torch switch 35 for connecting the conductive wire covered with a synthetic resin or the like to the pilot cable 34 insulated with a synthetic resin or the like to connect the conductive wire for carrying the high frequency to improve the Extend the plasma cutting torch 2
0 was attached.

FIG. 4 is a sectional view showing the tip of a conventional plasma cutting torch when the electrodes are solid. In this case, the cooling liquid guided from the outside of the torch passes through the cooling pipe of the torch main body, then cools the surface of the rear end of the electrode, further cools the torch main body through the cooling liquid return path inside the torch main body, and then to the outside of the torch. And go home.

Next, FIG. 5 is a sectional view showing the tip of a conventional plasma cutting torch when a coolant passage is provided in the electrode. In this case, the cooling liquid guided from the outside of the torch passed through the cooling pipe of the torch main body, then cooled the electrode through the cooling liquid passage in the electrode, and further cooled the torch main body through the cooling liquid return path in the torch main body. Later, I will return to the outside of the torch.

In the conventional example, Japanese Patent Publication No. 63-682 is disclosed.
As disclosed in Japanese Patent Publication No. 73-73, there has been a device in which the cooling of the rod electrode is enhanced by forming a water-cooled bottom inside the electrode support tube on a flat surface or a top surface of a truncated cone.

[0007]

The conventional torch constructed as described above has the following disadvantages.

First, when the electrode is solid, the electrode is only cooled at the rear end surface. Therefore, the cooling capacity of the electrode is low, and if the cutting current is increased, the life of the electrode is shortened due to heat generation of the electrode.

Secondly, if there is a coolant passage in the electrode, if the electrode continues to be used beyond its usage rate or life, the coolant will boil or burn out in the electrode, and the flow of the coolant will be interrupted. Sometimes. Continued use at this time or thereafter caused the torch body to burn out.

[0010]

According to a first aspect of the present invention, a cooling liquid introduced from outside the torch passes through a cooling pipe of the torch body and is formed inside the electrode. It has a path that cools the electrode through the coolant passage, cools the torch body through the coolant return path inside the torch body, and then returns to the outside of the torch.By a bypass hole provided in the cooling pipe of the torch body It has a structure for forming a path for diverting the cooling liquid from the cooling pipe to the cooling liquid return path.

Further, the second means of the present invention, in addition to the first means, can divide the cooling pipe into the torch body and the inside of the electrode in order to prevent the torch body from burning when the coolant is boiled in the electrode or when the electrode is burnt. The bypass hole is provided near or inside the electrode mounting portion of the cooling pipe.

Further, the third means of the present invention, in addition to the first means, further comprises a bypass hole for preventing the torch main body from being burned when the electrode is burned and the cooling liquid passage in the electrode is continuously used after being cut off. It has a bypass hole whose total cross-sectional area is set to 1/3 or more of the cross-sectional area of the cooling pipe.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the configuration of the first means, even if the coolant is shut off in the coolant passage in the electrode due to the boiling of the coolant in the electrode or the burning of the electrode, the coolant passing through the bypass hole can be used. This has the function of preventing the torch body other than the cooling pipe from being burned.

Further, the configuration of the second means can prevent the torch body including the cooling pipe in the torch body from burning when the coolant is boiled in the electrode or when the electrode burns out.

Further, according to the configuration of the third means, it is possible to prevent the torch main body from being burned when the electrode is burned and the cooling fluid passage in the electrode is shut off and the torch body is continuously used.

An embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, 1 is a torch main body, 2 is an electrode, 3 is a cooling pipe, 4 is a return path of a cooling liquid, 5
Is a coolant passage, 6 is a bypass hole, 7 is a cooling pipe II, 8
Is a chip. 2, reference numeral 11 denotes a flow rate of the coolant flowing through the coolant passage 5 in the electrode 2, and reference numeral 12 denotes a bypass hole 6.
Is a minimum coolant flow rate required for cooling the torch body 1.

In the torch of the present embodiment, the cooling liquid passage 5 through which the cooling liquid circulates to the inside of the electrode 2 and the cooling pipe 3 from the cooling pipe 3 to the cooling liquid return path 4 by the bypass hole 6 provided in the cooling pipe 3 in the torch main body 1. By providing a path for diverting the cooling liquid, even if the cooling liquid passage 5 in the electrode 2 is shut off due to boiling of the cooling liquid or burning of the electrode 2, the cooling liquid passing through the bypass hole 6 causes a portion other than the cooling pipe 3. Of the torch main body 1 can be avoided.

Further, by providing the cooling pipe II7 in the electrode 2, it is possible to prevent the cooling pipe 3 in the torch main body 1 from burning when the coolant boils or when the electrode 2 burns.

FIG. 2 shows the flow rate of the coolant flowing through the bypass hole 6 and the cooling flow through the coolant passage 5 in the electrode 2 when the total sectional area of the bypass hole 6 is changed with respect to the sectional area of the cooling pipe 3. 6 is a graph showing a liquid flow rate 11. According to this graph, the boiling of the cooling liquid or the burning of
If the cooling fluid passage 5 inside is continued to be used after being shut off,
If the total cross-sectional area of the bypass hole 6 is set to less than 1/3 of the cross-sectional area of the cooling pipe 3, the cooling liquid flow rate 13 required for cooling the torch main body 1 falls below the minimum, and even the torch main body 1 is burned. . Therefore, in order to secure the minimum required coolant flow rate 13 for cooling the torch body 1 when the coolant passage 5 in the electrode 2 is continued after the coolant passage 5 in the electrode 2 is shut off, the total cross-sectional area of the bypass hole 6 is reduced by the cooling pipe. 1/3 of 3
It turns out that it is necessary to make it above.

[0020]

According to the first aspect of the present invention, the cooling liquid guided from the outside of the torch passes through the cooling pipe in the torch main body, and then cools the electrode through the cooling liquid passage formed inside the electrode. The torch further has a route to return to the outside of the torch after cooling the torch main body through the cooling liquid return path in the torch main body, and the cooling pipe from the cooling pipe to the cooling liquid return path by a bypass hole provided in the cooling pipe in the torch main body. It has a structure that forms a path for diverting the coolant, and the coolant is not interrupted by boiling of the coolant or burning of the electrodes.
According to the means, by providing the cooling pipe II in the electrode, it is possible to prevent the cooling pipe in the torch body from burning when the electrode is burnt. According to the third means of the present invention, the total cross-sectional area of the bypass hole is reduced. Excellent effect that the torch main body can be prevented from being burned when the electrode is burned and the cooling liquid passage in the electrode is cut off by setting it to 1/3 or more of the cross-sectional area of the cooling pipe. It is a thing that plays.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a plasma cutting torch according to an embodiment of the present invention.

FIG. 2 is a graph showing the flow rate of the coolant flowing through the bypass hole and the flow rate of the coolant flowing through the coolant passage in the electrode when the total cross-sectional area of the bypass hole is changed with respect to the cross-sectional area of the cooling pipe.

FIG. 3 is a conceptual diagram showing the overall configuration of a conventional plasma cutting apparatus.

FIG. 4 is a cross-sectional view showing the tip of a conventional plasma cutting torch (when the electrode is solid).

FIG. 5 is a cross-sectional view showing a tip portion of a conventional plasma cutting torch (when there is a coolant passage in an electrode).

[Explanation of symbols]

 Reference Signs List 1 torch main body 2 electrode 3 cooling pipe 4 cooling liquid return path 5 cooling liquid passage 6 bypass hole 7 cooling pipe II 8 chip 11 cooling liquid flow rate flowing through cooling liquid passage in electrode 12 cooling liquid flow rate flowing through bypass hole 13 cooling torch main body Required coolant flow rate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Kiso 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A plasma cutting torch using a cooling liquid for cooling a torch body and an electrode, wherein a cooling liquid guided from the outside of the torch passes through a cooling pipe of the torch body and is then formed inside the electrode. Cooling the electrode through the coolant passage
In addition, it has a path to return to the outside of the torch after cooling the torch body through the cooling liquid return path in the torch body, and the cooling liquid from the cooling pipe to the cooling liquid return path by a bypass hole provided in the cooling pipe of the torch body. A plasma cutting torch having a structure for forming a branch path. 2. The plasma cutting torch according to claim 1, wherein the cooling pipe is divided into the torch body and the electrode, and the bypass hole is provided near or inside the electrode mounting portion of the cooling pipe. 3. The plasma cutting torch according to claim 1, wherein the plasma cutting torch has a bypass hole in which the total cross-sectional area of the bypass hole is 1/3 or more of the cross-sectional area of the cooling pipe.