JPH0220667A - Plasma torch - Google Patents

Abstract

PURPOSE:To avoid the adverse influence by electric corrosion of a plasma torch by connecting a negative electrode to an electrically conductive member and connecting directly cooling medium flow passages formed on a negative electrode sleeve and a positive electrode sleeve respectively to corresponding cooling medium flow passages formed to the inside of an insulating base substance. CONSTITUTION:The electrically conductive member 6 is inserted into a central through hole 5' of the insulating base substance 5 of the plasma torch. The negative electrode 1 is electrically joined to the electrically conductive member 6. The cooling medium flow passages 13 and 12 formed on the negative electrode sleeve 2 and the positive electrodes sleeve 3 respectively are connected directly to the cooling medium flow passages 9 and 7 formed to the inside of the insulating base substance 5. Packings P1 and P2 are provided respectively to joining parts of the respective cooling medium flow passages 13, 12, 9 and 7. By this method, the adverse influence by the electric corrosion of the plasma torch can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plasma torch used for processing such as welding and cutting.

[Conventional technology]

There are many processing methods that utilize arcs as electrical energy, and plasma arc welding, plasma arc cutting, etc. actively utilize the thermal energy of this arc.

A plasma arc torch is used for these processes,
Cooling of the plasma arc torch is important because the heat generated by the plasma arc torch not only results in power loss but also adversely affects the processing results and the life of the plasma arc torch. In many cases, tap water is generally used to cool such torches.

To explain a conventional water-cooled plasma arc torch with reference to FIG. 3, each member is shown as a block in order to simplify the explanation, but in reality there is a cathode sleeve part C1 outside the cathode part K. and anode sleeve part A3
are located concentrically and extend outside of the torch, respectively.
Equipped with Ex and E3. Discharge cap part E on the cathode part,
is connected to the supply mouthpiece S of the anode sleeve A3 by a flexible conduit CI, and the discharge mouthpiece E3 of the anode sleeve A is connected to the supply mouthpiece S2 of the cathode sleeve part Cs by a flexible conduit C2. Therefore, the cooling medium such as cooling water supplied from the external water supply source to the supply cap section St for the cathode section is transferred from the cooling medium flow path to the cathode section to its discharge cap flI E+→conduit C3-anode. Sleeve A, supply mouth parts S, I → its cooling medium flow path a → its discharge mouth part E → lead'llc! -Power Sword Sleeve C1
The cooling medium flows to the outside through the supply mouthpiece S, the cooling medium flow path C, and the discharge mouthpiece Et.

In addition to this, the torch is actually equipped with a hose for supplying inert gas, etc. into the torch, and an electric cable.

[Problem that the invention seeks to solve]

However, in the case of such a plasma torch, there is always a relatively thin supply mouth part S+ from the side of the plasma torch.
Sz, Sz, and outlet fitting E.

F and t protrude, and hoses and conduits are connected to these, so naturally the hose H is attached to the side of the plasma torch.
, , H, and the conduits C+ and Cz are protruding, and the plasma torch must be used, and there are restrictions on the directionality of the plasma torch, making it difficult to use.

In addition, hoses and conduits must be flexible and made of insulating material from the standpoint of electrical insulation, and cannot be firmly connected to the base by welding, resulting in water leakage. This problem is particularly likely to occur in cold regions.

Furthermore, although the cap parts E1 and Ss and E3 and Si, which have different potentials, are connected by insulating conduits, when tap water is used as a cooling medium, the corrosion of the cap part East is significant due to electrolytic corrosion, and the structure is deteriorated. For this reason, the life of the plasma torch was shortened because the wall thickness of the mouthpiece could not be made very thick.

Furthermore, it is necessary to electrically insulate each mouthpiece from the surrounding area, so the torch, mouthpiece, conduit, etc. must be molded with an insulating material or covered with an insulating cover, which reduces the size of the plasma torch. There is a drawback in this respect, especially in the case of molds, the plasma torch is heavy.

Furthermore, when molding with insulating material for electrical insulation,
If a problem arises, such as when the mouthpiece becomes corroded due to electrolytic corrosion within the molded insulating material, the plasma torch itself usually has to be discarded.

[Means for solving problems]

In this invention, in order to eliminate the drawbacks of the conventional plasma torch as described above, an insulating base body having a plurality of medium flow passages is prepared, and the cooling medium flow passages of the eleventh and second sleeves are connected to the medium of the insulating base body. The present invention is characterized in that the first and second sleeves are assembled with the insulating base so as to be connected to corresponding ones of the flow passages.

〔Example〕

Embodiments of the plasma arc torch according to the present invention will be described with reference to FIGS. 1 and 2 (A) to (D).

In these figures, l is a cathode rod made of tungsten material, 2 is a cathode sleeve with a removable tip 2' at its tip, 3 is an anode sleeve with a removable tip 93' at its tip, and 4 is a tip. 0 provided in section 3',
a constricted hole having a diameter of about 1 to 0.5 square centimeters, 5 an insulating base made of an insulating material and having an annular cross section, 6 a conductive member disposed within the central hole 5' of the insulating base 5 and supporting the cathode rod l; 7.8.9
and 10 is a cooling medium flow path formed in the insulating base 5;
Reference numeral 11 denotes a cooling medium flow path formed by cutting a U-shaped cross section around the conductive member 6; 12 represents a cooling medium flow path formed in the anode sleeve 3; and 13 represents a cooling medium flow path formed in the cathode sleeve 2. This is a flow passage, and illustration of the gas passage and electrical system is omitted. Here, the members indicated by black circles related to the coolant flow passages are packings such as O-rings, but symbols indicating these packings are omitted except for P1sP2.

As can be seen from the figure, the cooling medium flow passages 13 and 12 provided in the cathode sleeve 2 and the anode sleeve 3 to cool them, respectively, are directly connected to the cooling medium flow passage formed in the insulating base 5. The place has its characteristics. To explain this point in detail, one end of the cooling medium passage 12 of the anode sleeve 3 is connected to one end of the cooling medium passage 7 of the insulating base 5 at the end of the anode sleeve 3, and the other end is connected to the end of the cooling medium passage 7 of the anode sleeve 3. It is connected to one end of the cooling medium flow path 8 of the insulating base 5 at another position. Further, one end of the coolant flow passage 13 of the cathode sleeve 2 is connected to one end of the coolant flow passage 9 of the insulating base 5 at a certain point on the side end of the cathode sleeve 3, and the other end is connected to the side of the cathode sleeve 3. It is connected to one end of the cooling medium flow path 10 of the insulating base 5 at another location on the end. Furthermore, both ends of the cooling medium flow path 11 of the conductive member 6 are connected to the conductive member 6.
Cooling medium flow of the insulating base 5 at the side wall surface portion of vs.8.
11, respectively.

One end of the cathode sleeve 2 and the anode sleeve 3 are assembled into the insulating base 5 with respective packings interposed therebetween so as to obtain the above-mentioned structure.

In the plasma torch having such a configuration, the cooling medium supplied from an external cooling medium source (not shown) to the cooling medium passage 7 of the insulating substrate 5 is supplied to the cooling medium passage 1 of the anode sleeve 3.
2→Cooling medium flow path 8 of insulating substrate 5-Cooling medium flow path 11 of conductive member 6→Cooling medium flow path 9 of insulating substrate 5—Cooling medium flow path 13 of cathode sleeve 2→Cooling medium flow of sintered base 5 The water is drained through a flow path consisting of channel 10. As a result, the cathode sleeve 2 and the anode sleeve 3 are directly cooled, and the cathode rod l is cooled via the conductive member 6. In this case, even if electrochemical corrosion occurs as in conventional plasma torches, these connections will be The cathode sleeve 2, anode sleeve 3, and conductive member 6 of the plasma torch are smaller than the wall thickness of the mouthpiece.
Since the wall thickness of the connecting part of the coolant flow path is much thicker, there is virtually no negative effect, especially at the inlet of the coolant flow path,
By using a gasket with a diameter that is somewhat larger than the diameter of the outlet, there is no risk of water leakage due to electrolytic corrosion even if tap water is used as a cooling medium for a long time.

The end of the cathode sleeve 2 is incorporated into the large-diameter central hole of the insulating base 5, and the cooling medium flow path 13 of the cathode sleeve 2
Since the inlet and outlet of the insulating base 5 are connected to the coolant flow passages 9 and 10 of the insulating base 5 at their side ends, the gaskets P and Pt surrounding the mouths of the coolant flow passages at the connection parts prevent water leakage. It serves to stabilize the cathode sleeve 2 in the central hole of the insulating substrate 5.

Note that the positions and connections of the cooling medium flow passages of the insulating substrate 5 and the cooling medium flow passages 13 and 12 of the cathode sleeve 2 and anode sleeve 3 shown in FIGS. 1 and 2 are merely examples, and for example, A flow path corresponding to the coolant flow path 7 of the insulating substrate 5 connected to the water source may be connected to the coolant flow path 13 of the cathode sleeve 2.
It is also possible to connect the cooling medium passages of the anode sleeve 3 and the respective cooling medium passages of the anode sleeve 3 through short cooling medium passages within the insulating base 5, and various modifications are possible.

Although not shown, the insulating base 5 is provided with a plasma gas flow path at a location that does not intersect with the cooling medium flow path, and the conductive member 6 is provided with a center gas flow path. Further, the end face of the insulating base 5 is provided with an anode sleeve terminal, a cathode sleeve terminal, etc., and these electrical connection terminals are connected to the anode sleeve and the cathode sleeve, respectively, by connecting conductors extending through holes in the insulating base 5.

〔Effect of the invention〕

As described above, according to the present invention, the cooling medium flow passages formed in the conductive member electrically connected to the cathode rod, the cathode sleeve, and the anode sleeve are connected to the cooling medium previously formed in the insulating base. Since they are directly connected to the corresponding parts of the flow path, the wall thickness of the conductive member and each sleeve will not be adversely affected by electrolytic corrosion even if electrolytic corrosion occurs due to the use of very simple tap water as a cooling medium. Since the plasma torch generally has a thickness of about There is no need to cover it with a cover to ensure physical insulation.

Furthermore, maintenance is also possible, and only broken parts can be replaced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the plasma torch according to the present invention, and FIGS. 2(A) to (D) are A-A' in FIG. 1.
FIG. 3 is a diagram illustrating a conventional plasma torch, which is a cross-sectional view taken along lines BB', CC', and DD'. 1- cathode rod, 2- cathode sleeve, 3- anode sleeve, 4- narrowed hole, 5- insulating substrate, 6- conductive member,
7-13-Cooling medium flow path, PIP, -Packing

Claims (4)

[Claims] (1) An insulating base including a central through hole and a plurality of medium flow paths; a conductive member inserted into the central through hole of the insulating base and electrically coupled to an external power source; and a conductive member coupled to the conductive member. first and second sleeves assembled with the insulating substrate, each having a cooling medium flow passage coupled to a corresponding one of the medium flow passages of the insulating substrate; A plasma torch comprising: a packing provided at a joint between a medium flow path and the cooling medium flow path of each of the first and second sleeves. (2) In a plasma torch in which a first sleeve having a first cooling medium flow path and a second sleeve having a second cooling medium flow path are arranged concentrically around the cathode rod, at least an insulating base having third, fourth, fifth and sixth coolant flow passages, both ends of the first coolant flow passages are coupled to one end of each of the third and fourth coolant flow passages; Both ends of the second cooling medium flow path are connected to one end of each of the fifth and sixth cooling medium flow paths, and the other ends of the fourth and fifth cooling medium flow paths are connected to cooling conductive members. 1. A plasma torch, characterized in that the third and sixth cooling medium flow paths are connected to each other through a medium flow path, and are arranged such that the other ends of the third and sixth coolant flow paths are a water supply side and a drainage side, respectively. (3) In a plasma torch in which a first sleeve having a first cooling medium flow path and a second sleeve having a second cooling medium flow path are arranged concentrically around the cathode rod, at least an insulating base having third, fourth, fifth and sixth coolant flow passages, both ends of the first coolant flow passages are coupled to one end of each of the third and fourth coolant flow passages; and both ends of the second coolant flow passage are coupled to the other end of the fourth coolant flow passage and one end of the fifth coolant flow passage, and the other end of the fifth coolant flow passage is connected to the other end of the fourth coolant flow passage. The cooling medium flow path of the conductive member communicates with the sixth coolant flow path, and the other ends of the third and sixth coolant flow paths are arranged to be a water supply side and a drainage side, respectively. plasma torch. (4) In a plasma torch including a first sleeve disposed to surround a cathode rod and a second sleeve disposed outside the first sleeve, a portion of the second sleeve an insulating base having a fitting hole into which the cooling medium is inserted, and a cooling medium passage hole provided in the side wall of the fitting hole and coupled to the cooling medium passage hole of the second sleeve; A plasma torch characterized in that a ring-shaped packing is provided between the side wall of the insertion hole of the insulating base and the outer wall of the second sleeve so as to surround the small medium passage hole.