JPH0790372B2 - Arc plasma heating device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc plasma heating device, and more particularly to a heating device using an arc plasma diffusion flame.

[0002]

2. Description of the Related Art For example, a gas flame of oxygen acetylene or LPG has been widely used conventionally for welding, working, cutting, etc. of metal, and in recent years, a plasma flame of arc discharge capable of obtaining higher energy density has been used. It came to be used. (More recently, carbon dioxide laser beams and the like that can realize higher energy densities have been used, but these are excluded here because their application fields are limited.)

[0003]

However, the gas flame method utilizing the gas flame of the chemical reaction heat is
Since it uses dangerous pressure gas such as highly explosive oxygen and acetylene, each pressure cylinder container is required,
Since it involves a relatively large volume and weight, there are many safety restrictions on its transportation, on-site handling, etc. In addition, the cost was heavy.

On the other hand, in the plasma method, higher energy density can be obtained, but as the plasma working gas, argon,
Inert gas such as helium, diatomic molecule gas of nitrogen, hydrogen and oxygen, mixed gas of these, or air, etc., and to scatter and remove the processed part such as cutting and boring of the metal base material, relatively large pressure is required. It is necessary to supply gas at a flow rate (for example, in the case of air, pressure is 5 to 7 kg / cm ² , flow rate is 50 to 80 l /
min), so the cost was high. Also, for example, in the case of copper pipe piping work in the field installation work of air conditioning equipment, cutting work by plasma is easy,
For the brazing work, etc., it is necessary to gently heat the vicinity of the joint to prevent the base material of the pipe from locally melting, but this condition cannot be satisfied, so this kind of It could not be used for brazing work.

The present invention has been made in consideration of the above situation, and even in the case of the site work as described above, the apparatus can be easily transported and installed, and the handling is safe and the cost is low. It is an object of the present invention to provide an arc plasma heating device of this type that can be brazed.

[0006]

Therefore, in the present invention, an arc plasma heating apparatus of this type is provided as follows : (1) A heated metal base material as a center electrode and one electrode
A voltage is applied between them to perform arc discharge and
A plasma is generated between the two electrodes through a nozzle that surrounds the electrodes.
By supplying 1 to 5 l / min of air as moving gas
To generate a diffusion plasma flame between the two electrodes,
The flux is used as a heating source in the diffusion range of the metal base material.
Alternatively, (2) apply a voltage between a pair of electrodes that are coaxially opposed to each other.
Arc discharge and enclose the pair of electrodes.
Through said nozzle between the electrodes and the heated metal matrix, by supplying air of 1 to 5 l / min as the plasma working gas, said two electrodes and diffusion plasma flame between the heated metal matrix to generate, by the heat flux configured to a heating source diffusion range of the metals preform, it is intended to achieve the object.

[0007]

The diffusion columnar plasma flow generated by the above-described structure becomes a reducing flame due to the small amount of air, and heats the vicinity of the processed portion of the metal base material relatively slowly during brazing work, for example. , There is no fear of local melting of the base metal, and the light wavelength spectrum of this reducing flame contains more infrared rays in the longer wavelength region than the short wavelength ultraviolet region in the high temperature. A heating effect can also be expected, and it is generally very easy to supply, for example, a commercial power source, etc., and the supply of air as a plasma working gas is very small, so a small air compressor or the like can be used , Cheap and not dangerous.

[0008]

EXAMPLES The present invention will be described below based on examples. FIG. 1 shows a schematic cross-sectional view of the main part of an embodiment of a transfer type arc plasma heating apparatus according to the present invention. Reference numeral 1 is a torch nozzle as a plasma generator, 2 is a center electrode, 3 is a metal base material to be heated, which also serves as a counter electrode of the center electrode 2, and a voltage is applied to both electrodes 2 and 3 from a 100/200 V commercial power source. . Reference numeral 5 indicates the control device.

A feature of the present invention is that the plasma working gas is applied between the nozzle 1 and the center electrode 2 at a pressure of, for example, 1 kg / cm ^2.
In the following, a relatively small amount of air having a flow rate of 1 to 5 l / min or less was sent through a small air compressor (not shown). A reducing plasma diffusion plasma flow P is formed, which causes the base material 3
Since the processed part is heated relatively slowly in a relatively wide range, there is no fear of local melting, and it can be used safely and at low cost, for example, for a brazing process.

(Other Embodiments) FIG. 2 is a view corresponding to FIG. 1 showing an embodiment of non-transfer type arc plasma, and the same (corresponding) components as in FIG. 1 are represented by the same reference numerals. In this embodiment, instead of using the base metal 3 as one of the electrodes as in the transitional type, a second concentric cylindrical shape is provided around the center electrode 1.
The comparatively small amount of air A as the plasma working gas that is sent between the electrodes 2 and 2a conforms to the first embodiment and is formed as a plasma jet. The same effect as described above can be obtained by the diffusion plasma flow P.

In each of the above-mentioned embodiments, examples of brazing joining of steel pipes and the like have been described. However, the principle of the present invention is not limited to this, and a high energy density is not required locally. Of course, it can be applied to other applications such as heating and hot water supply of water, and when cutting of the steel pipe or the like is required, a conventionally used high energy density torch can be used. Good.

[0012]

As described above, according to the present invention,
Since a relatively small amount of air is used as the plasma working gas of the arc plasma heating device, a plasma diffusion flow that is a reducing flame is formed, so that it can be easily used for brazing, for example, at a low cost. A highly safe heating device of this kind was obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a fractured cross section of an essential part of an embodiment of a transfer type arc plasma heating device.

FIG. 2 is a view corresponding to FIG. 1 of an embodiment of a non-transfer type arc plasma heating device.

[Explanation of reference symbols] 2 center electrode 2a electrode 3 metal base material 4 power supply A air P diffusion plasma flow

Claims (2)

[Claims] 1. A heated object as a center electrode and one electrode
While applying a voltage between the metal base materials to perform arc discharge,
A nozzle that surrounds the center electrode is used to connect the electrodes between the electrodes.
Supply 1 to 5 l / min of air as plasma working gas.
By, to generate a diffusion plasma flame between the two electrodes,
The heat flux is used as a heat source in the diffusion range of the metal base material.
An arc plasma heating device having the above-mentioned configuration. 2. A voltage between a pair of electrodes coaxially opposed to each other.
Is applied to cause arc discharge and the pair of electrodes
Between the both electrodes and the metal base material to be heated through a nozzle surrounding the
Supply 1 to 5 l / min of air as plasma working gas
Between the electrodes and the metal base material to be heated by
To generate a diffusion plasma flame in the
Characterized by being configured as a heating source in the diffusion range of the material
Arc plasma heating device.