JPH04104854A - Method and device for plasma flame atomization - Google Patents

Abstract

PURPOSE:To efficiently form a high-temp. and high-speed plasma flame by introducing a liq. or gaseous fuel into a line for generating a plasma arc and converting the fuel to electric plasma to produce fuel gas plasma and mixing oxygen or compressed air into the plasma to burn the fuel. CONSTITUTION:A liq. or gaseous fuel is introduced into a first chamber from an inlet 17. When liq. fuel is used, the fuel is force-fed by nitrogen gas, etc., atomized and introduced into the first chamber 16. The liq. or gaseous fuel introduced from the inlet 17 is converted to electric plasma by the plasma arc formed by the voltage impressed between a cathode 11 and an anode 12, and fuel gas plasma is produced. The fuel gas plasma current is mixed with the oxygen or compressed air from a supply port 19. The fuel gas plasma is then mixed with the oxygen or compressed air, and combustion is caused by the high-temp. and fuel gas plasma in the second chamber 18. Consequently, the high-temp. and high-speed plasma flame is formed and discharged from a discharge port 20, and a high-temp. and high-speed plasma flame is efficiently formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a plasma flame atomization method and U' apparatus for forming an extremely high temperature and high speed plasma flame.

The method and apparatus according to the present invention are suitable for heat treatment of objects such as metals, thermal spraying of objects to be treated such as metals and ceramics, cutting and welding of objects to be treated, dehydration and pulverization of various wastes, etc.
Effective for decomposition processing, etc.

(Prior art) Plasma flame using an electrician's energy source as a heat source has a high temperature state (
2,500 to 9,000°C), which is sufficient to melt particles of high melting point metals, ceramics, etc., but the gas flow is not very fast. The gas flow in a conventional plasma flame is on the order of 400 to 600 m/sec.

For this reason, the speed of the particles flying in the gas flow does not increase, and it is not possible to obtain a strong collision force against the base material itself, making it impossible to improve the adhesion of the coating particles.

U.S. Pat. No. 4,370,538 describes a method and apparatus for ultra-high velocity dual flow metal flame atomization. The method and apparatus of this patent includes a first stream formed by a plasma arc of inert gas such as argon, helium, nitrogen, etc. and a second stream formed by combustion of air/fuel in an internal burner arrangement under high pressure. It is composed of a combination of The first stage created a relatively low-velocity, high-temperature state, and the second stage created an ultra-high-velocity jet. This conventional method and apparatus adopts a configuration in which a second stream is sent to surround the first stream, so that particles melted by the first stream are accelerated by the second stream. It is known to first form a plasma flame, melt particles within this plasma flame, and then accelerate the particles by a combustion flame formed by another process.

(Problem to be Solved by the Invention) This invention differs from the above method in that it does not use the inert gas used to form a conventional plasma flame, but instead converts the RLi body or gaseous fuel into internal scum. It is an object of the present invention to provide a plasma flame atomization method and apparatus for efficiently forming a high-temperature, high-velocity plasma flame by roughly forming a combustion flame by using the present invention as a plasma flame forming gas.

That is, the plasma flame spraying method according to the present invention introduces liquid or gaseous fuel into a path for generating a plasma arc, and converts the introduced fuel into an electric blaster to generate a fuel gas blaster. It is characterized by forming a gas and mixing it with oxygen or compressed air to produce a fuel gas.

Further, the apparatus according to the present invention includes a torch body having an electrode and a passage for generating a plasma arc, an introduction means for introducing a liquid or gas with a fuel rate of 1 into the passage of the torch body, and the torch body. a supply means for supplying oxygen or compressed air into the passage of the torch body; and a fuel gas blaster formed in the passage of the torch body, which is formed by converting liquid or gaseous fuel into electric blaster, and mixing the oxygen or compressed air. It is characterized by being equipped with a burning front chamber that allows the user to immerse himself in the wind.

Furthermore, the apparatus according to the present invention is characterized in that it is configured to generate a plasma arc within the combustion chamber for converting liquid or gaseous fuel into electric plasma.

The method and apparatus according to the present invention are characterized in that liquid or gaseous fuel, which has been turned into internal scum, is directly used as the plasma flame forming gas.

In other words, the fuel residue is directly used as the plasma flame forming gas,
The idea is to mix oxygen or air here and there to create a combustion state during the plasma flame formation process. As a result, it is possible to form a plasma flame that combines the thermal energy inherent in a plasma flame with the expansion energy due to combustion. In this case, the combustion is at high temperature,
Since it is carried out in a high pressure environment, a gas expansion far greater than the critical expansion occurs. This expansion energy is
Creates a plasma flame with a high-speed flow that was previously unobtainable.

In such a method and apparatus, the formation of a plasma flame and the formation of a combustion flame can be performed in the same process, and a high-temperature, high-velocity plasma flame can be efficiently formed.

In addition, in the method according to the present invention, liquid or gaseous fuel is converted into electric plasma to form fuel gas plasma, and oxygen or compressed air is mixed with this and combusted, which is further converted into electric plasma. This includes the case where the plasma generation process and the combustion process are performed repeatedly, and also includes the case where they are performed simultaneously.

Gaseous fuel is turned into electrical plasma by molecular decomposition and ionization, and liquid fuel is turned into electric plasma by vaporizing the liquid into gas and then by molecular decomposition and ionization of the vaporized fuel. In this case, the vaporization of the liquid fuel is facilitated by the heat generated by the electrical plasma formation.

Gaseous fuels include acetylene, propane, propylene, butane, natural scum, coal scum, etc. In addition, liquid fuels include karin, kerosene, light oil, alcohol, fats and oils, and the like. Among these, acetylene burns completely at high temperatures and can form a plasma flame in a reducing atmosphere, while propylene has a higher vapor pressure than other hydrocarbon gaseous fuels and is easier to handle. In addition, propane, natural gas, or other gases are relatively inexpensive and can be easily used. Kerosene is also inexpensive, easy to use, and convenient to handle.

The basic structure of the device according to the present invention includes: a torch body having an electrode and a passageway for generating a plasma arc; an introduction means for introducing liquid or gaseous fuel into the passageway of the torch body; )・- supply means for supplying oxygen or compressed air into the passage of the main body;
A combustion front chamber is formed in the passage of the I/-ch body and mixes and burns a fuel gas plasma formed by converting liquid or gaseous fuel into electric plasma and oxygen or compressed air. It is.

Such an apparatus is embodied as an apparatus of a form not shown in the schematic diagrams of FIGS. 1-4.

In FIG. 1, the entire torch body is formed into a cylindrical shape,
A passageway (10) for generating blastomatitis is formed inside. A cathode (11) made of a conductive material such as tungsten is provided at one end of the passage (10). Around the cathode (11) is an anode (12) made of a conductive member made into a cylindrical shape so as to constitute a part of the passageway (10).
is provided. An insulating member (13) is interposed between the cathode (11) and the anode (12). Furthermore, cooling channels (+4) (+5) are provided for cooling the cathode (11) and the anode (12).

The tip passage opening of the anode 12) is formed narrowly, and the space (first chamber) (16) formed between the tip passage opening and the cathode (11) is used for introducing liquid or gaseous fuel. A mouth (17) is provided. Inlet port (1
Although not shown, a supply pipe for liquid or gaseous fuel filled in a tank is connected to 7) via a flow meter, a control valve, etc.

In front of the tip passage opening of the anode 12), there is provided another space (second chamber) (+8) as a combustion chamber in which the liquid or gaseous fuel is converted into electrical plasma and burns the gaseous plasma. .

This second chamber (18) is designed to be supplied with oxygen or compressed air for burning the fuel casserosol, and its supply port (19) is connected to the first chamber (16) and the second chamber (18). passage between (10
) It is provided so as to face the inside of the varus U second chamber (18). Although not shown, a supply pipe for supplying oxygen or compressed air filled in the tank is connected to the supply port (19) via a flow meter, a control valve, etc. The state of the supply of oxygen or compressed air from these supply ports (19) is adapted to regulate the valve-shaped combustion of the fuel-powered blaster in the second chamber (18). Note that both or one of these supply ports (19) may be used.

A water channel (21) for circulating cooling water is provided around the second chamber (18), which is a combustion chamber. The tip of the second chamber (18) serves as a discharge port (20) and is formed into a narrow throat shape.

In the apparatus shown in FIG. 1, liquid or gaseous fuel is first fed into the first chamber from the inlet (17). When the fuel to be fed is liquid fuel, it is fed under pressure with a gas such as nitrogen gas or with a pump so that it is atomized and sent into the first chamber (16).

Next, the liquid or gaseous fuel introduced through the inlet (17) is converted into electric plasma by a plasma arc formed by a voltage applied between the cathode (11) and the anode (12). This forms fuel gas plasma. The fuel gas plasma becomes a plasma flow and is mixed with oxygen or compressed air supplied from the supply port (19). The mixing ratio varies depending on the fuel used. Note that when the same fuel is used, a plasma flame in an oxidizing atmosphere or a reducing atmosphere can be formed by increasing or decreasing the amount of oxygen or compressed air supplied.

The fuel gas plasma is then mixed with oxygen or compressed air, and combustion occurs in the second chamber (18) with the fuel gas plasma at high temperature. As a result, a high-temperature, high-velocity plasma flame is formed, and the discharge port (20
). In the method and apparatus of this invention, theoretically, the temperature is 2500 to 5000°C and the gas flow is 400 to 4000 m.
,/second range of plasma flame formation is possible.

In addition, when thermal spraying is performed using the plasma flame, for example, a nozzle (not shown) is installed at the tip of the discharge port (20) from the side.
The material is introduced into the plasma flame through the nozzle.

The device shown in FIG. 2 is similar in form to the device shown in FIG. 1, but the second chamber (+8), which is a combustion chamber, is configured as an anode (12) made of a conductive member.

Therefore, in this example, the second chamber (18
) produces both combustion and electric plasma, making it possible to form a plasma flame with a high temperature.

Further, the device shown in FIG. 3 is applied to a transfer arc. This equipment is mainly used for cutting metal,
Since it is used for welding, only fuel gas plasma in a high temperature state may be used.

In the devices shown in FIGS. 1 to 3, the supply port (19) for supplying oxygen or compressed air is connected to the passage (1) between the first chamber (16) and the second chamber (18).
0) and the second chamber (18); however, in the above device, these supply ports (18)
9), the device may be provided with only one of them.

The apparatus shown in FIG. 4 has a configuration in which the formation and combustion of a fuel scum blast are performed simultaneously. In this device, an inlet (17) for introducing liquid or gaseous fuel and a supply port (19) for supplying oxygen or compressed air are arranged in parallel.
They are guided into the same chamber (22).

The device shown in Fig. 5 is designed to emit a fuel gas plasma formed by converting liquid or gaseous fuel into electric plasma directly into the air, and directs the emitted fuel gas plasma toward the discharge port (20). A supply port (23) for actively supplying oxygen or compressed air is arranged. The supply port (23) is connected to the discharge port (20) as shown in FIG.
In addition to a configuration in which a plurality of discharge ports (20) are arranged around the periphery of the discharge port (20), as shown in FIG. The apparatus shown in FIG. 5 burns fuel gas plasma in the air, and does not have a combustion chamber divided like the apparatuses shown in FIGS. 1 to 4. For this reason, the first
Although the plasma flame generated by the apparatus shown in Figures to Figure 4 cannot be made to have a high velocity, it is possible to ensure a plasma flame with a high velocity compared to a normal plasma flame that does not use energy from combustion. .

In addition, in the device illustrated above, the inside of the passage of the torch body is
As an introduction means for introducing this liquid or gaseous fuel, an introduction port (17) is introduced into the first chamber, and a fuel introduction port is provided in the second chamber to further assist combustion. It may be provided.

The device according to the present invention is not limited to the structures illustrated above, but includes various combinations of the structures of the illustrated devices.

(Effects of the invention) As explained above, the method and device according to the present invention,
By using fuel gas directly as the plasma flame formation residue, the process of forming plasma flame and the process of forming combustion flame are performed in the same process, and a high-temperature, high-speed plasma flame is efficiently formed. can be done.

Further, when the method and apparatus according to the present invention are used, plasma flames having various temperatures and velocities can be formed by combining energy from electric plasma formation and energy from combustion.

Therefore, the method and apparatus according to the present invention can be used for heat treatment of objects such as metals, thermal spraying of objects to be treated such as metals and ceramics, cutting and welding of objects to be treated, as well as dehydration of various wastes.
It can be applied to crushing, decomposition processing, blasting furnaces, etc.

[Brief explanation of drawings]

1 to 4 are cross-sectional views showing each embodiment of the apparatus according to the present invention, FIG. 5 is a cross-sectional view showing an apparatus using the method according to the present invention, and FIGS. 6 and 7 are FIG. 6 is a front view showing the collapse of the supply port of the device shown in FIG. 5; Explanation of symbols 10... Passage, 11... Cathode, 12... Anode, 16... First chamber, 17... Inlet, 18
...Second chamber 19... Supply port, 20... Discharge port. Figure 5 Kudani → Figure 6 Figure 7

Claims (1)

[Claims] 1) Introducing liquid or gaseous fuel into a path for generating a plasma arc, converting the introduced fuel into electric plasma to form fuel gas plasma, and mixing oxygen or compressed air with this. A plasma flame atomization method characterized by combustion. 2) A torch body having an electrode and a passage for generating a plasma arc, an introduction means for introducing liquid or gaseous fuel into the passage of the torch body, and introducing oxygen or compressed air into the passage of the torch body. a combustion chamber formed in the passage of the torch main body for mixing oxygen or compressed air with fuel gas plasma formed by converting liquid or gaseous fuel into electrical plasma and combusting the mixture. A plasma flame spray device characterized by comprising: 3) The plasma flame atomizing device according to claim 2, wherein the plasma flame atomizing device is configured to generate a plasma arc for converting liquid or gaseous fuel into electrical plasma within a combustion chamber.