JPH06102271B2 - Torch for plasma cutting - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to a plasma cutting torch using a working gas.

Prior Art No. 7 of the plasma arc cutting method using working gas
Shown in the figure. In the figure, 10 is a compressor that compresses the working gas and sends it to the torch tip, 11 is a regulator that adjusts the secondary pressure of the working gas to a constant value, 12 is a plasma cutting power source for supplying power, and 13 is a base material. A grounding cable connecting 17 and the power source 12, and 14 is a plasma cutting torch.
The torch 14 has a built-in electric run and also has a cooling cable 15 and a torch switch cable 16 for sending working gas to the tip of the torch.
It is composed of

The shape of the tip portion 18 of the conventional cutting torch 14 will be described below.

The structure of the tip of the conventional cutting torch is as shown in FIGS. 1 is an electrode base material in which a cathode material such as zirconium or hafnium is embedded in the tip portion, 2 is a chip that squeezes a plasma arc to a base metal, 3 is an electrode 1 and chip 2 that are electrically insulated and supplied from a cable The orifice 5 having a small diameter hole for splitting the generated working gas and generating a swirling flow for compressing the plasma arc prevents the conductive portion from being exposed to the outside, and the torch body metal fitting 4
It is a nozzle having a role of fixing the electrode 1, the tip 2, and the orifice 3 by screwing with, and flowing the working gas passing through the groove portion (spline portion) of the tip 2 as a secondary flow for cooling the tip. It is made of an insulating material such as ceramic.

In the plasma arc cutting, the high temperature plasma flow is narrowed in the tip 2, and in the contact cutting, the heated base material is brought into contact with the tip 2, so that it is easily damaged by heat.
Therefore, as described above, the working gas is branched, and the working gas is also flown between the groove 6 and the nozzle 5 provided on the outer peripheral surface of the chip to cool the chip 2.

Problems to be Solved by the Invention As shown in FIG. 3, in the conventional plasma torch tip structure, the working gas 8 fed from the cooling cable 15 is supplied.
After passing through the torch body metal fitting 4, passes through a small hole 7 provided on the outer periphery of the orifice 3 to form a swirling flow, which narrows the plasma arc and causes the plasma flow to flow out from the chip central hole and the outer periphery of the chip 2. It is divided into a secondary flow that passes through the provided groove portion 6 and cools the chip.

A small hole 7 provided on the outer circumference of the orifice 3 divides the circumference into equal parts and is opened so as to contact the inner surface of the orifice to form a swirling flow.

Further, the groove portion (spline portion) equally provided on the outer peripheral portion of the chip 2 forms a gas passage with the nozzle 6.

On the other hand, since the orifice 3 and the tip 2 are combined at a free position, the positional relationship between the small hole portion 7 of the orifice 3 and the groove portion 6 on the outer periphery of the tip 2 may be linear. In this case, the working gas may collide with the tip portion and be branched, or may go straight in the groove portion 6 of the tip. The balance was generated, the straightness of the plasma arc was impaired, and it was one of the factors that the base metal could not be cut straight.

Means for Solving the Problems In order to solve the above problems, the plasma cutting torch of the present invention is an electrode base material having an electron emission surface, and is arranged so as to cover the electrode base material, and the root portion is A hollow tip having a large diameter and provided with a groove on the outer periphery of the root portion, and insulatingly holding the electrode base material and the tip, and having a small hole in the peripheral wall, and a working gas advancing direction with respect to the small hole It is provided with a hollow orifice provided with an annular protrusion on the outer peripheral wall surface on the downstream side, and a hollow nozzle fitted to the root of the tip from the outside and protecting the conductive part.

Operation With the above configuration, the working gas fed from the cooling cable passes through the torch body fitting and then the gas passage formed by the outer wall surface of the orifice and the inner wall surface of the nozzle, and the same as in the conventional product, on the side surface of the orifice. Although it is divided into the small hole and the groove on the tip circumference, the annular projection is located on the outer peripheral surface of the orifice between them, so it is evenly affected by the positional relationship between the small hole on the side of the orifice and the tip groove. The flow is divided, and as a result, a uniform swirling flow can be obtained.

Embodiment FIG. 1 and FIG. 2 show an embodiment of the present invention. Reference numeral 1 is an electrode base material in which a cathode material such as zirconium or hafnium is embedded at the tip, 2 is a chip for constricting the plasma flow, 3
Is an orifice having a small diameter hole for electrically insulating the electrode base material from the chip 2, dividing the working gas 8 supplied from the fluid cable, and generating a swirling flow for compressing the plasma flow. Reference numeral 5 denotes a metal fitting, which prevents the conductive part from being exposed to the outside and is screwed into the torch body metal fitting 4 so that the electrode base material 1, the tip 2, the orifice 3
Is a nose for fixing working fluid and flowing a working gas passing through the groove portion of the chip 2 as a secondary flow for cooling the chip, and is made of an insulating material such as ceramic. The working gas 8 passes through the torch body metal fitting 4, and then passes through the gas passage formed by the outer wall surface of the orifice 3 and the inner wall surface of the nozzle 5, and then is split into the inner and outer surfaces of the tip 2.
Since there is an annular projection 9 on the entire circumferential surface of the orifice between the small hole 7 provided on the side surface of the orifice and the groove portion 6 provided on the outer peripheral surface of the chip, the small hole 7 on the side surface of the orifice and the groove 6 on the outer peripheral surface of the chip are formed. The flow is evenly divided without being affected by the positional relationship of, and as a result, a uniform swirling flow is obtained.

EFFECTS OF THE INVENTION As described above, according to the present invention, since an excellent swirling flow is obtained, excellent straightness of the plasma arc is maintained and cutting performance can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a plasma cutting torch showing an embodiment of the present invention, FIG. 2 is a perspective view of the essential part, and FIG. 3 is a sectional view of an essential part of a conventional plasma cutting torch. Fig. 3
FIG. 5 is a sectional view taken along the line AA, FIG. 5 is a sectional view taken along the line BB in FIG. 3, FIG. 6 is a perspective view of the relevant portion, and FIG. 7 is a perspective view of a general plasma cutting apparatus. 1 ... Electrode substrate, 2 ... Chip, 3 ... Orifice, 4
…… Torch body fittings, 5 …… Nozzle, 6 …… Groove, 7 ...
… Small holes, 8 …… Working gas, 9 …… Protrusions.

Claims (1)

[Claims] 1. An electrode base material having an electron emitting surface, and a hollow chip which is arranged so as to cover the electrode base material, has a large diameter at its root, and has a groove on the outer periphery of the root. A hollow orifice for insulatingly holding the electrode base material and the chip, having a small hole in the peripheral wall, and providing an annular protrusion on the outer peripheral wall surface on the downstream side in the working gas advancing direction with respect to the small hole; The tip has a hollow nozzle that fits from the outside and protects the conductive part, and the working gas diverted to the inner peripheral surface side of the chip through the small hole by the protrusion is the small hole. A torch for plasma cutting, characterized in that the working gas is turned into a swirl flow, the arc is compressed, and the working gas diverted to the outer peripheral surface side of the chip by the protrusion flows out after passing through the groove part of the chip. .