JPH01150478A - Torch for plasma cutting - Google Patents

Abstract

PURPOSE:To improve the cooling effect of a chip and to extend the service life by forming a small chamber in the space with the chip external wall of the chip groove part outlet port and equipping a guide ring provided with locking part to a nozzle on the outer face part. CONSTITUTION:An operation gas 5 is passed through a chip groove part (spline part) 6 after being shunt by the small hole of an orifice 3, comes in the small chamber formed by the inner wall of a guide ring 7 and the chip 2 outer wall and flowed out along the chip wall face after its flowing direction being changed at right angle in the chip wall face direction. The cooling effect of the chip 2 is thus increased and the service life can be extended.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a plasma cutting torch using a working gas.

Conventional technology A device for plasma arc cutting using a working gas is shown in Fig. 3, where 9 is a compressor that compresses the working gas and sends it to the tip of the torch, and 10 is a unit that adjusts the secondary pressure of the working gas to a constant value. 11 is a power source for plasma cutting that supplies power, 13 is a base material 12 and a power source 11
14 is a plasma cutting torch.

The torch 14 has a built-in electric lamp and is composed of a cooling cable 15 and a torch switch cable 16 that send working gas to the tip of the torch.

The structure of the tip of the conventional cutting torch 14 is as shown in FIG. 1 is an electrode base material with a cathode material such as zirconium or hafnium embedded in the tip; 2 is a chip that squeezes the plasma arc to the base material; 3 is a cable that electrically insulates the electrode base material 1 and the chip 2; The orifice 4 has a small diameter hole for separating the working gas supplied from the main body and generating a swirling flow that constricts the plasma arc. By combining, electrode 1, tip 2, orifice 3
The nozzle is made of an insulating material such as ceramic and has the role of fixing the chip 2 and causing the working gas passing through the groove e of the chip 2 to flow as a secondary flow for cooling the chip.

In plasma arc cutting, the tip 2 is exposed to a high-temperature plasma flow eυ, and in contact cutting, it comes into contact with a heated base material, so it is susceptible to damage due to heat. Therefore, as described above, the chip 2 is cooled by dividing the working gas and causing the working gas to flow also between the groove 6 provided on the outer peripheral surface of the chip and the nozzle 4 (secondary flow).

Problems to be Solved by the Invention As shown in FIG. 2, in the tip structure of a conventional plasma torch, the tip 2 is electrically insulated from the orifice 3 and nozzle 4, and is also thermally insulated. can say,
The chip 2 is cooled by the heat capacity of the chip itself and the heat absorption of the working gas (secondary flow) in the chip cooling reservoir.

In order to make the heat capacity of the chip a dog, you can simply make the dimensions into a dog, but considering the functionality of the torch, this is not an appropriate method, and if you increase the number of grooves, the heat capacity will decrease. In addition to this, the amount of working gas (secondary flow) flowing inside the chip, which constricts the plasma flow, decreases, and the flow division does not work properly.

In addition, the working gas flow (
(secondary flow) has not been sufficiently effective and has not become a continuous flow. That is, the working gas that has passed through the groove provided on the outer circumferential surface of the chip simply flows parallel to the chip, and does not flow along the outer circumferential surface of the chip.

Therefore, a sufficient cooling effect of the tip 2 could not be obtained, leading to premature damage to the tip 2. As a result, generation of a tight plasma arc was impaired, and cutting performance was also significantly deteriorated.

Means for Solving the Problems In order to solve the above problems, the plasma cutting torch of the present invention has an electrode base material having an electron emitting surface at the center, and an orifice connected to a tip that constricts the plasma flow. In a plasma cutting torch that has a structure in which working gas is divided into the inner and outer surfaces of the tip, the inner surface is in contact with the outer surface of the tip having a plurality of holes or gaps on the outer periphery, the inner surface has a diameter smaller than the diameter of the bottom surface of the tip groove, and the tip at the outlet of the tip groove has a diameter smaller than the bottom diameter of the tip groove. It is equipped with a guide ring that forms a small chamber between the guide ring and the outer wall, and has a locking part for the nozzle on the outer surface.

Effect In the above configuration, the working gas that has passed through the chip groove (spline part) does not travel straight but is applied to the side surface of the chip at right angles or close to it.

Since the fluid flows along the surface, the gas that hits the side of the chip is then forced to flow along the outer surface of the chip.

Furthermore, since the tip is in contact with the guide ring, the heat absorbed by the tip is conducted to the guide ring. The inner wall of the guide ring forms a working gas passage with the outer wall of the orifice.
It has a heat dissipation effect, and the heat capacity of the chip is higher than that of conventional products.

Embodiment FIG. 1 shows an embodiment of the present invention. 1 is an electrode base material with a cathode material such as zirconium or hafnium embedded in the tip, 2 is a chip that constricts the plasma flow, and 3 is a working gas that electrically insulates electrode 1 and chip 2 and is supplied from a fluid cable. A is a guide ring made of copper or copper alloy that contacts the outer surface of the chip and changes the outflow direction of the working gas.

Reference numeral 4 denotes a nozzle made of ceramic or the like that protects the conductive part and fixes the electrode 1, tip 2, orifice 3, and guide ring by screwing it into the main body metal fitting 8.

After the working gas 5 is divided by the small hole of the orifice 3,
It passes through the chip groove part (spline part) 6 and enters the small chamber formed by the outer wall of the chip 2 and the inner wall of the guide ring 7.
After the outflow direction is changed to be perpendicular to the direction of the chip wall surface, it flows out along the chip wall surface. Therefore, the cooling effect of the chip 2 is greatly increased.

However, by changing the inner diameter φD12 of the guide ring 7, the difference between the working gas (plasma flow) flowing between the electric conductor 1 and the inner surface of the tip 2 and the working gas flowing along the outer surface of the tip 2 (secondary flow) can be improved. It is also possible to change the diversion ratio to suit the cutting conditions.

Another advantage is that the electrode 1, tip 2, and orifice 3 of the conventional product can be used as they are, and by simply changing the guide ring and the nozzle 4, the life of the tip 2 can be extended two to three times compared to the conventional product.

Effects of the Invention As described above, by providing the guide ring of the present invention, the cooling effect of the chip can be greatly improved and the life span can be extended, and the effects are outstanding.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a plasma cutting torch showing an embodiment of the present invention, FIG. 2 is a sectional view of a conventional plasma cutting torch, and FIG. 3 is a perspective view of a general plasma cutting device. 1... Electrode base material, 2... Chip, 3.
...Orifice, 4...Nozzle, 5...
... Working gas, 6... Chip groove, 7...
...Guide ring, 8...Body screw fitting. Name of agent: Patent attorney Toshio Nakao and one other person (d
> Figure 2 (αn

Claims (1)

[Claims] A plasma cutting torch has a structure in which an electrode base material having an electron emitting surface is placed in the center, and a working gas is divided into the inner and outer surfaces of the tip by an orifice connected to a tip that constricts the plasma flow. Alternatively, the outer surface of the chip and the inner surface with a gap are in contact with each other, the diameter is smaller than the diameter of the bottom surface of the chip groove, a small chamber is formed between the chip outer wall at the outlet of the chip groove, and a locking part with the nozzle is provided on the outer surface. A plasma cutting torch characterized by having a guide ring.