JP3591233B2 - Plasma cutting torch - Google Patents

Description

[0001]
TECHNICAL 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]
[Prior art]
A conventional plasma cutting apparatus using a cooling liquid will be described with reference to FIGS. 3, 4, and 5. FIG. In FIG. 3, 20 is a plasma cutting torch, 21 is a compressor for compressing a 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 current for the plasma cutting torch 20. , 24 is an installation cable for connecting the base material 25 and the cutting power source 23, and 26 is a water absorption pump.
[0003]
From the cutting power source 23, a drain hose 31 having a built-in conductive wire and draining the cooling water, a water supply hose 32 for sending the cooling water to the torch, a gas hose 33 for sending the working gas, and a good arc start. The cable of the torch switch 35 for connecting and disconnecting a pilot cable 34 insulated with a synthetic resin or the like to a conductive wire for carrying a high frequency to perform ON / OFF of an output by connecting the conductive wire to the The plasma cutting torch 20 was attached to the tip.
[0004]
Next, FIG. 4 is a cross-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 goes to the outside of the torch. And go home.
[0005]
Next, FIG. 5 is a cross-sectional view showing a tip portion of a conventional plasma cutting torch when a coolant passage is provided in an 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, we go back to the outside of the torch.
[0006]
In a conventional example, as disclosed in Japanese Patent Publication No. 63-68273, 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. Was.
[0007]
[Problems to be solved by the invention]
The conventional torch configured as described above has the following disadvantages.
[0008]
First, if the electrodes are solid, the electrodes are 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.
[0009]
Second, if there is a coolant passage in the electrode, if the electrode continues to be used beyond its usage rate and life, the coolant will boil in the electrode or the electrode will burn out, and the flow of the coolant will be interrupted. is there. Continued use at this time or thereafter has caused the torch body to burn out.
[0010]
[Means for Solving the Problems]
In order to solve this problem, the first means of the present invention is to cool the electrode by passing a coolant introduced from the outside of the torch through a cooling pipe of the torch body, and then through a coolant passage formed inside the electrode. Further, there is a path for cooling the torch main body through the cooling liquid return path in the torch main body and returning to the outside of the torch, 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 main body. Having a structure for forming a path for diverting the water.
[0011]
Further, the second means of the present invention, in addition to the first means, allows the cooling pipe to be divided into the torch main body and the inside of the electrode in order to prevent the torch main body from burning when the cooling liquid in the electrode or the electrode burns out. It is characterized in that the hole is provided in the vicinity of the electrode mounting portion of the cooling pipe.
[0012]
Further, the third means of the present invention further comprises, in addition to the first means, the total cross-sectional area of the bypass hole in order to prevent the torch main body from being burned when the electrode is burned and the coolant passage in the electrode is continuously used after being cut off. Is 1/3 or more of the sectional area of the cooling pipe.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
With the configuration of the first means, even if the coolant is shut off in the coolant passage in the electrode due to coolant boiling or electrode burning in the electrode, the coolant passing through the bypass hole causes the torch body other than the cooling pipe to be cut off. Burnout has an action that can be avoided.
[0014]
Further, by the configuration of the second means, it is possible to prevent the torch main body including the cooling pipe in the torch main body when the coolant is boiled in the electrode and the electrode is burned out.
[0015]
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 coolant passage in the electrode is shut off and the torch body is continuously used.
[0016]
Hereinafter, an embodiment of the present invention will be described 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 coolant return path, 5 is a coolant passage, 6 is a bypass hole, 7 is a cooling pipe II, and 8 is a chip.
In FIG. 2, reference numeral 11 denotes a coolant flow rate flowing through the coolant passage 5 in the electrode 2, 12 denotes a coolant flow rate flowing through the bypass hole 6, and 13 denotes a minimum coolant flow rate required for cooling the torch main body 1. .
[0017]
In the torch according to the present embodiment, the coolant flows from the cooling pipe 3 to the coolant return path 4 by the bypass hole 6 provided in the cooling pipe 3 in the torch main body 1 together with the coolant passage 5 through which the coolant circulates into the electrode 2. Even if the coolant passage 5 in the electrode 2 is cut off due to the boiling of the coolant or the burning of the electrode 2 by providing the branch path, the torch main body other than the cooling pipe 3 is cooled by the coolant passing through the bypass hole 6. Burnout 1 can be avoided.
[0018]
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 is boiled or when the electrode 2 burns.
[0019]
FIG. 2 shows a coolant flow rate 12 flowing through the bypass hole 6 and a coolant flow rate 11 flowing 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. It is a graph showing. According to this graph, when the cooling liquid passage 5 in the electrode 2 is shut off due to boiling of the cooling liquid or burning out of the electrode 2, the total cross-sectional area of the bypass hole 6 is 1 to the cross-sectional area of the cooling pipe 3. If the ratio is set to less than / 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. It is understood that it is necessary to set the cross-sectional area to be 1/3 or more of the cross-sectional area of No.
[0020]
【The invention's effect】
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, and further cools the torch main body. It has a path to return to the outside of the torch after cooling the torch main body through the cooling liquid return path inside, and diverts the cooling liquid from the cooling pipe to the cooling liquid return path by the bypass hole provided in the cooling pipe in the torch main body It has a structure that forms a path, and the coolant is not interrupted by boiling of the coolant or burning of the electrode. According to the second means of the present invention, by providing the cooling pipe II in the electrode, the burning of the electrode is prevented. In some cases, burning of the cooling pipe in the torch body can be prevented, and according to the third means of the present invention, the total cross-sectional area of the bypass hole is set to 1/3 or more of the cross-sectional area of the cooling pipe, so that the electrode is formed. Burning and cooling inside the electrode One in which an excellent effect that it is possible to prevent the burnout of the torch body when continuously used after the passage has been cut off.
[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 flow rate of a coolant flowing through a bypass hole and an electrode when a total cross-sectional area of the bypass hole is changed with respect to a cross-sectional area of a cooling pipe. FIG. 3 is a graph showing the flow rate of a coolant flowing through a coolant passage in the inside. FIG. 3 is a conceptual diagram showing the entire configuration of a conventional plasma cutting apparatus. FIG. 4 is a cross-sectional view showing the tip of a conventional plasma cutting torch (electrode is solid). in the case of)
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]
DESCRIPTION OF SYMBOLS 1 Torch main body 2 Electrode 3 Cooling pipe 4 Coolant return path 5 Coolant passage 6 Bypass hole 7 Cooling pipe II
8 Chip 11 Coolant flow rate flowing through the coolant passage in the electrode 12 Coolant flow rate flowing through the bypass hole 13 Minimum required coolant flow rate for cooling the torch body

Claims (3)

A plasma cutting torch that uses a cooling liquid to cool the torch body and electrodes, and a cooling liquid guided from outside the torch passes through a cooling pipe of the torch body, and then a cooling liquid passage formed inside the electrode. It has a path that cools the electrode and further cools the torch body through the cooling liquid return path inside the torch body and then returns to the outside of the torch, and cools from the cooling pipe by the bypass hole provided in the cooling pipe of the torch body A plasma cutting torch having a structure for forming a path for diverting a cooling liquid to a liquid return path. The cooling pipe to be divided up into interior and the electrode torch body, the plasma cutting torch according to claim 1 wherein in which a bypass hole in the vicinity of the electrode mounting portion of the cooling pipe. The plasma cutting torch according to claim 1, wherein the plasma cutting torch has a bypass hole in which a total cross-sectional area of the bypass hole is 1/3 or more of a cross-sectional area of the cooling pipe.

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