JP2955064B2 - Plasma spraying equipment and spraying equipment for repairing linings in industrial kilns - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma spraying apparatus, and more particularly to a plasma spraying apparatus having a power supply device for converting DC power into multi-phase AC power and capable of generating a large-sized plasma jet, and an industrial furnace furnace lining. It relates to a repair spraying machine.

[0002]

2. Description of the Related Art In a conventional plasma spraying apparatus, plasma is generated by generating plasma with a single pole of + or-direct current, so that large-scale large-scale spraying cannot be performed and powerful spraying can be performed. However, it was difficult to raise the temperature and speed of the plasma, but this was very difficult and was used only for some small spraying operations. Further, when the thermal spray material hardly enters the center of the plasma and deviates from the center of the plasma, the material does not melt sufficiently and is hit against the object to be sprayed, resulting in poor thermal spraying. In recent years, there has been an apparatus in which gas is burned to generate an explosive jet flame, thereby making it possible to perform thermal spraying. However, it has been difficult to obtain a temperature of 2700 ° C. or more, and there is naturally a limit.

[0003] More recently, corrosion phenomena of metal products have rapidly increased due to air pollution, acid rain, and the like. For this reason, the appearance of large-sized large-area thermal spraying for preventing rusting of steel frames and the like has been desired.
Multi-arc technology has proven to be effective in treating and regenerating polluting industrial waste beyond conventional arc spraying equipment, but if this principle is applied to plasma spraying, it can be stable, large, and narrow in conventional narrow areas. And various types of thermal spraying beyond the local thermal spraying.

A thermal spraying machine for repairing the lining of an industrial kiln will be briefly described below as a specific example of a conventional plasma spraying apparatus. As thermal spraying for the conventional industrial kilns laying the refractories on the inner surface of the refractory brick 421, FIG. 11 as shown in (a), SiO ₂ spray gun 423 or propane gas burner, by heavy oil burner or the like, Al ₂ O ₃ , Ca
A mixture 424 such as O was sprayed on the inner surface of the refractory brick 421 to form a lining film 422. Then, as shown in FIG. 11 (b), after the furnace was actually used for melting the metal 425, the inner surface of the refractory brick 421 was again sprayed with a refractory material for the next use, so that the lining film 42 was used.
No. 2 was formed and repaired.

[0005]

However, a single-phase alternating current is usually used as a power source for the above-mentioned thermal spraying apparatus. As a device for converting a three-phase alternating current into a single-phase alternating current in order to obtain this single-phase alternating current, a Scott wiring, a three-phase low frequency system, an inverter system, and the like are known. There is a problem that phase imbalance occurs, and there is a problem that power efficiency is poor.

That is, the above-mentioned Scott wiring or the like has a complicated circuit configuration, and as a power supply device, the entire device becomes large.
In addition, it is difficult to take out a stable current, for example, an excessively large current flows twice in one of the three phases, and there is a problem particularly in reliability of the power supply device.

[0007] Further, an inverter system which has been recently adopted, after rectifying an alternating current, raises the frequency to 10,000 or more for lighting and several hundred to 1200 cycles for welding and spraying, and inputs this to a transformer. This is a method of rectifying the output again, which can reduce the size and weight of the transformer, but is extremely expensive, inefficient, and has many failures. Therefore, a compact, lightweight and efficient power supply device has been demanded.

Further, the conventional thermal spraying machine for repairing the lining of an industrial kiln has the structure as described above. Recently, the lining material has been made easily soluble in order to enhance the repairing efficiency by a thermal spray gun. However, this deteriorates the fire resistance, which hinders the actual use of melting the metal at a high temperature, and also causes problems such as making the molten metal impure. For example, recently, high-grade metals such as shape memory alloys and superconducting materials have been developed.
CaO is preferable for melting metals such as i and Nb,
Even if this CaO is used for lining, it cannot be baked by the conventional method. That is,
Even if CaO is lined, CaO is sublimated, that is, it becomes ragged by absorbing moisture. Thus, there is a problem that lining is difficult due to poor sublimation resistance.

The present invention has been made in view of the above points, and enables stable thermal spraying over a large area beyond conventional narrow area thermal spraying and various thermal spraying, and is a completely new compact and lightweight. It is an object of the present invention to provide a plasma spraying apparatus that includes a power supply device that efficiently converts DC power into polyphase AC power and that can perform spraying efficiently using a DC power supply such as a battery.

Further, the present invention makes the spraying operation very easy,
Equipped with a power supply device that converts DC power into multi-phase AC power, which is completely new, compact, lightweight and efficient, and performs efficient spraying of refractories using a DC power source such as a battery. An object of the present invention is to obtain a thermal spraying machine for repairing an industrial kiln lining.

[0011]

SUMMARY OF THE INVENTION A plasma spraying apparatus according to the present invention has positive and negative contacts connected to positive and negative voltages of a DC power supply, and opens and closes the positive and negative contacts. A switch circuit that can switch between the positive and negative contacts; a reactance circuit that is connected to the switch circuit and has a reactance component; A neutral terminal connected to an intermediate potential of a negative voltage, and a control circuit for sequentially controlling opening and closing or switching operation of the switch circuit with a predetermined time difference between the neutral terminal and the output terminal of the conversion unit. A power supply device for outputting a multi-phase alternating current, a neutral electrode connected to the neutral terminal, and a multi-terminal around the neutral electrode. A multi-arc electrode group in which a large number of electrodes corresponding to the number of phases of the multi-phase alternating current that generate arcs are uniformly arranged on the same circumference in one or more stages, and each of the plurality of electrodes And a plasma spraying part connected to the output terminal of the corresponding phase converter.

[0012] In the plasma spraying apparatus according to the present invention, in the power supply device, first to third converters are provided as a plurality of converters, and the control circuit is configured to output the output obtained by one switching of the switch circuit. 1 / per cycle of waveform
Each switch circuit is controlled to be switched by a phase difference of 3. In the plasma spraying section, three electrodes or 6
A multi-arc electrode group consisting of electrodes is arranged in a plurality of stages in the vertical direction, and the arrangement of the arc electrodes in each stage is adjusted with respect to the arrangement of the arc electrodes in the upper or lower electrode group so as to generate an arc even between the upper and lower electrodes. It is shifted little by little.

[0013] In the plasma spraying apparatus according to the present invention, in the power supply device, the reactance circuit is configured to change its reactance component based on a reactance control signal, and the control circuit is configured to switch the switch based on a timing control signal. The switching operation of the positive and negative contacts in the circuit and the timing of the switching operation between the positive and negative contacts are configured to be changed, and one or both of the reactance control signal and the timing control signal are used.
One or both of the shape of the output waveform of the power supply device and the frequency of the AC output are made variable with time.

The spraying machine for repairing the lining of an industrial kiln according to the present invention has positive and negative contacts connected to the positive and negative voltages of a DC power supply, and opens and closes the positive and negative contacts or the positive side. , A switch circuit capable of switching between the negative side contacts, a reactance circuit having a reactance component and connected to the switch circuit, and a plurality of conversion units for converting DC to AC; A neutral terminal connected to the intermediate potential of the negative voltage, and a control circuit for sequentially controlling the opening and closing or switching operation of the switch circuit with a predetermined time difference, wherein the neutral terminal is connected to the output terminal of each converter. A power supply device for outputting a multi-phase alternating current between the electrodes, and applying each phase voltage of the power supply device to each of a plurality of electrodes to generate a plurality of arcs between the electrodes; A multi-phase, multi-electrode multi-arc generator for ejecting a plasma arc from the electrode tip, and a means for supplying a material for lining to the non-transitional plasma arc, wherein the material for lining is produced by the non-transitional plasma arc The material is heated and melted and irradiated to a refractory to perform thermal spraying.

[0015]

According to the present invention, there is provided a conversion circuit comprising a switch circuit capable of outputting a positive or negative voltage of a DC power supply intermittently or by switching between a positive and negative voltage, and a reactance circuit connected to the switch circuit. Since a power supply device including a switch circuit control circuit and outputting a multi-phase alternating current is used, a DC power source such as a battery can be used, and three-phase imbalance and a flicker phenomenon can be avoided. In addition, since a transformer is not required in the power supply device, the entire device can be reduced in size and weight.

In the power supply device, by changing the opening / closing or switching timing of the switch circuit and the reactance component of the reactance circuit, it is possible to obtain various polyphase AC outputs having different waveforms and frequencies in accordance with the material of the spray material. Can be.

Also, since a multi-arc multi-electrode, for example, three or six electrodes is used for plasma spraying,
A large plasma jet can be obtained.

Further, a multi-arc is used for plasma spraying, a multi-arc electrode group consisting of three or six electrodes is arranged in a plurality of stages, and the arrangement of the arc electrodes in each stage is changed so that an arc is generated between the upper and lower electrodes. Since the arrangement of the arc electrodes of the upper or lower electrode group is slightly shifted, a rotating jet of plasma is generated by a strong rotating magnetic field, and strong plasma spraying can be performed.

According to the present invention, in the thermal spraying machine for repairing the lining of an industrial kiln, the power supply device having the above-described configuration is used, and each phase voltage of the power supply device is applied to each of the plurality of electrodes, so that a plurality of electrodes are provided between the electrodes. A non-transferring plasma arc is ejected from the electrode tip by generating an arc, and the lining material is supplied into the non-transferring plasma arc, and the lining material is heated and melted by the non-transferring plasma arc. Since the thermal spraying is performed by irradiating the refractory material, a DC power source such as a battery can be used, and it is possible to avoid three-phase imbalance and a flicker phenomenon, to reduce the size and weight of the entire apparatus, and to perform thermal spraying. Work can be performed very easily and reliably.

[0020]

FIG. 1 is a block diagram showing a configuration of a plasma spraying apparatus according to one embodiment of the present invention. In the figure, 1
Is a DC power supply, and 2a to 2c are first to third converters for converting a DC current into an AC current, respectively, and are composed of switch circuits 21a to 21c and saturation reactors (reactance circuits) 22a to 22c, respectively. 24a-2
4c and 25a to 25c are the switch circuits 21a to 21c, respectively.
The positive and negative contacts of 21c are connected to the positive and negative voltages of the DC power supply, respectively. 6a to 6c are conversion units 2
Output terminals a to 2c and 7 are neutral terminals connected to an intermediate potential between the positive and negative voltages of the DC power supply 1. Reference numeral 31 denotes a phase difference (１ ／ T ₀ ) which is １ ／ times one cycle T ₀ of an output waveform obtained by one switching of the switch circuit.
This is a control circuit for switching control of each switch circuit. Reference numeral 100 denotes a DC power supply 1, converters 2a to 2c, and a switch control circuit 31.
And a power supply device for outputting a three-phase alternating current between the output terminals 6a to 6c, and a plasma spraying unit 300 for receiving the three-phase alternating current output and performing plasma spraying.

FIG. 2 shows a specific structure of the plasma spraying section 300, and FIGS. 2 (a) and 2 (b) show the spraying section 3 respectively.
7A and 7B are a vertical sectional view and a horizontal sectional view of a nozzle portion 300a of No. 00, respectively. In the drawing, reference numeral 301 denotes a neutral electrode disposed at the center of the nozzle portion 300a, 302a denotes a working gas (first gas) obtained by mixing argon gas, nitrogen gas, carbon gas and the like, and 314 denotes a tip portion containing the neutral electrode 301. The electrode 301 has a cylindrical shape close to a conical shape.
And a first cylindrical body forming a space A between the working gas 3
02a passes through the space A from the inside of the cylindrical body to the opening 3
14a. Reference numeral 315 denotes a second cylindrical body which has a substantially conical cylindrical shape containing the first cylindrical body 315 and forms a space B between the cylindrical body 314 and the second gas 302b. The space is supplied to the opening 315a through the space B, and the first multi-arc electrode group 304 is arranged in the space B. 316 is the second cylinder 3
A third cylindrical body having a cylindrical shape close to a conical shape and containing therein a cylindrical rod 315. The third cylindrical body has a space C between the cylindrical body 315 and the cylindrical body 315. Or the first thermal spray material 317a and the third gas 302c such as a composite or a powder thereof.
Is supplied, and a second multi-arc electrode group 305 is arranged in the space C. Further, reference numeral 309 denotes a fourth cylindrical body having a cylindrical shape in which the third cylindrical body 316 is built, and this is a space D between the cylindrical body 316 and the fourth cylindrical body.
The second spraying material 317b such as Ni and the fourth gas 302d are supplied from the inside to the opening 309a through the inside, and the third multi-arc electrode group 306 is arranged in this space D. I have. Note that the fourth gas 302d may be air. Reference numeral 320 denotes a plasma jet ejected from the nozzle portion 300a toward the spray target 370, and 380 denotes a thermal spray coating formed on the surface of the spray target 370.

FIG. 3 shows the arrangement of the arc electrodes in the nozzle portion of the plasma spraying apparatus.
-6,5-1 to 5-6,6-1 to 6-6 respectively correspond to the first, second and third multi-arc electrode groups 304 and 305,
In the first to sixth arc electrodes constituting the 306, the six arc electrodes of each group are arranged such that their tips are located on the same circumference, so that a multi-arc is generated between them. Has become. Here, the first and fourth electrodes of each electrode group
Are the a-phase of the three-phase AC output of the power supply device 100, that is, the output terminal 6a of the converter 2a, and the second and fifth arc electrodes are the b-phase, that is, the output terminal 6 of the converter 2b.
b, the third and sixth arc electrodes are connected to the c-phase, that is, the output terminal 6c of the converter 2c, and the neutral electrode 301 is connected to the neutral terminal 7 of the power supply device 100. And each electrode group 304, 30
The six arc electrodes 5 and 306 are arranged such that the electrodes whose applied voltages are shifted by one phase between the upper and lower electrode groups are opposed to each other so as to face each other. And a rotating magnetic field can be obtained.

Next, the operation will be described. When the switching circuits 21a to 21c are switched and controlled by the control circuit 31, a saw-tooth current having a drooping characteristic of a predetermined period is generated between the output terminals 6a to 6c and the neutral terminal 7 of each of the converters 2a to 2c. Each of them is guided to output a multi-phase alternating current as shown in FIG.
And the first arc electrodes 4-1 and 4-1 of the electrode groups 304 to 306.
5-1, 6-1 to sixth arc electrode 4-6, 5-6, 6-
6, and between the arc electrodes, a multi-arc is generated, and multi-arc spraying is performed. In this case, the following effects can be obtained.

In a conventional three-phase / single-phase conversion power supply,
Although the obtained single-phase output is a sine wave, the power supply output value according to the present invention sharply rises to a high voltage, from which a sawtooth wave which becomes zero in a drooping manner is obtained. A stable arc is obtained. That is,
This power supply device is essentially a power supply having drooping characteristics, and is very convenient for thermal spraying.

By adjusting the control circuit,
The frequency of the output current can be set to, for example, 300, 400,
It can be set freely, such as 600 cycles, and the most efficient arc can be used. If the frequency is set so that the operation timing of the switch circuit can be continuously changed by adjusting the knob of the control circuit, an output of an arbitrary frequency can be obtained. Further, since the frequency can be increased in this way, the size and weight of the device can be greatly reduced. Also, since the structure is simple and small and light, the manufacturing cost can be greatly reduced. The higher the frequency of the arc, the higher the efficiency of the arc, which leads to a reduction in the size and weight of the thermal spraying apparatus.

In the conventional device, the no-load voltage is 6
Although 0 V to 100 V was required, the present invention can sufficiently reduce the voltage, and is safe, easy to handle, does not require technical skills, and is easy to automate.

The inductance L of the reactance circuit
5B, the shape of the drooping characteristic can be changed as shown by waveforms X to Z as shown in FIG. 5 (b). Can be set. For example, by adjusting the inductance value L of the reactance circuit, the sawtooth waveform can be sharpened, that is, the output current can have a drooping characteristic in which the initial voltage is high and the voltage drops sharply thereafter. There is also an effect that the arc characteristics can be made better than the three-phase multi-arc using.

Further, since the arc is small and lightweight and the arc is stable, the entire plasma spraying apparatus using the same can be reduced in size and weight.

Further, in such a plasma spraying apparatus, a large cross-sectional area, that is, a large plasma flow can be obtained by the multi-arc between the six arc electrodes of the multi-arc electrode group. , The third and third stages are provided so that an arc is generated even between the upper and lower stages, so that a very powerful and wide-area multi-arc is formed, the plasma area (including the thickness) is large, and there is no defective melting. , High quality thermal spraying can be performed. Further, since the plasma flow 320 is very thick and long, large-sized and high-speed thermal spraying can be performed. In addition, since the arc is strong, it is possible to spray hardly soluble tungsten or alumina. Further, the above mixture can be subjected to thermal and abrasion resistant thermal spraying, and alloy thermal spraying becomes possible. Further, since the present invention is a multi-electrode and has a large circular opening 321 in the center, a metal rod, a ceramic rod, a ceramic powder in a metal powder, a composite rod 322 and the like are inserted therein to perform thermal spraying. There is the advantage that it can be done.

Further, since a gas such as an inert gas or air is injected from the space between the respective cylinders, thermal spraying can be performed by a strong plasma flow. Further, if a higher DC voltage is applied to the lower side of each electrode group, the plasma flow can be further enhanced.

Further, the center of the insertion rod 322 is made hollow, and a combustion gas 323 such as an inert gas, air, or acetylene is intensively jetted from the hollow, so that thermal spraying using an explosive jet flame can be performed.

Further, in the present invention, since the amount of arc plasma is large, the energy can be increased by generating a magnetic field by an induction coil or the like and accelerating and rotating the generated electrons and ions.

Further, the multi-arc plasma of the present invention is stable and produces good results in reduced-pressure plasma spraying in a reduced-pressure vessel, and the present invention is also effective for thermal spraying in water.

Further, if a metal wire is used as the above-mentioned arc electrode and sent out in accordance with its consumption, and its tip is always located near the above-mentioned opening 321, mass spraying, formation of overlay, or wire It is also possible to perform alloy spraying or composite spraying of different metals.

FIG. 4 shows some more specific examples of the configuration of the neutral electrode in the above embodiment.
FIG. 4A shows a neutral electrode 332 made of a hardly soluble metal.
And the six arc electrodes 331 surrounding the
FIG. 4 (b) shows a case where a neutral electrode 332 made of a hardly soluble metal is centered and three arc electrodes 331b are arranged so as to surround the neutral electrode. FIG. 4
In (c), 330 is a bundle of a plurality of wires, and each wire may be made of a different kind of metal. In this case, the bundle of wires must be strong. FIG. 4 (d) shows a metal pipe 333 in which a stranded wire 334 is inserted in the center, and FIG. 4 (e) shows a metal pipe 33.
In the center of 3, powder of tungsten or alumina 33 which is hardly soluble
FIG. 4 (f) shows the case where ceramic powder 336 is placed in the center of a metal pipe 333, and FIG.
An inert gas 338 is ejected from the center of a pipe 337 having a double structure made of two different metals.
In any case, after melting the metal pipe,
It can dissolve stranded wire, powder, etc. in it.

The configuration of each neutral electrode has the following effects.

When spraying a tungsten or carbon rod, a metal and ceramic, or a very hardly soluble material, three arc electrodes 331b (FIG. 4 (b)) or six arc electrodes 331a (FIG. 4 (a)) are used. The hardly soluble metal 332 is arranged at the center, and a neutral is connected to the metal.
Then, an arc is generated between all the arc electrodes 331a or 331b and the neutral refractory metal 332, and a very strong arc is generated in combination with the arc between the outer peripheral arc electrodes 331a or 331b. Anything can be sprayed. For example, this thermal spraying can be used to protect a large-area furnace inner wall surface and to prevent corrosion of a large iron bridge.

The center of the hardly-fusible welding rod 332 is made hollow, and an inert gas, air, ceramic,
By injecting 339 such as combustion gas (hydrogen, acetylene, etc.) at an appropriate pressure, it is difficult to dissolve, or large powders (for example, naturally occurring iron-broken particles), which have been impossible so far.
Can be simply and efficiently performed by plasma spraying.

Here, in order to more effectively utilize the explosive power of the combustion gas for thermal spraying, it is better to inject the combustion gas at the tip end of the electrode rather than at the inside of the electrode. And the space D between the fourth cylindrical body.

The center neutral electrode 332
Is melted to form a wire-shaped metal bundle (FIG. 4 (c)
) Or by inserting a metal stranded wire 334 to be alloyed into a metal pipe 333 (FIG. 4D). Instead of the metallic stranded wire 334, ceramic powder 336 (FIG. 4 (f)), tungsten and alumina powder 335 (FIG. 4 (e)) can be used. Further, an inert gas 338 can be ejected from the pipe (FIG. 4 (g)).

The output waveform of the power supply device is not limited to the one shown in the above embodiment, but may be another waveform. For example, the reactance circuit is configured so that its reactance component changes based on a reactance control signal, and the control circuit performs opening and closing operations of positive and negative contacts in the switch circuit based on a timing control signal. If the timing of the switching operation between the positive and negative contacts is changed, one or both of the reactance control signal and the timing control signal can be used to change the waveform of the AC output and / or its frequency. Can be changed over time, for example, from 180 cycles to 60 cycles.

FIGS. 6A and 6B show an example in which the switching operation of the switch circuit in the first embodiment is changed to an opening and closing operation of a positive or negative contact, and FIG. An example is shown in which the number and arrangement of arc electrodes in each electrode group are also changed. However, here, only the first multi-arc electrode group 304 is shown, and the other second and third multi-arc electrode groups 305 and 306 are omitted because they are the same as the first electrode group.

In the modification of FIG. 6A, in the first embodiment, the operation of each of the switch circuits 21a to 21c is only the opening and closing operation of the positive contacts 24a to 24c. In this case, a multi-phase output having a waveform as shown in FIG. 7A is obtained, and in one electrode group, a total of 12 arcs are generated between the neutral electrode 71 and the arc electrode and between the adjacent arc electrodes.
Actually, since there are three stages of such electrode groups, multi-arc spraying can be performed by a plurality of arcs, which is three times as many as 36 arcs and an arc generated between the upper and lower electrode groups.

FIG. 6B shows the switching circuits 21a to 21a.
The operation of 21c is only the opening / closing operation of the negative contacts 25a to 25c. In this case, the same multi-arc spraying as in FIG. 6A is performed by the spraying current having the waveform shown in FIG. 7B. be able to.

Further, in a modification shown in FIG. 6C, each electrode group is constituted by arranging nine arc electrodes 4-1 to 4-9 in sequence on the same circumference at equal intervals. 4-1 and 4
-4, 4-7 to the output terminal 6a of the first converter 2a, the arc electrodes 4-2, 4-5, 4-8 to the output terminal 6b of the second converter 2b, and the arc electrode 4-3. , 4-6, and 4-9 are connected to the output terminal 6c of the third converter 2c. Here, a neutral electrode is not used. In this case, in one electrode group, a total of nine arcs are generated between adjacent arc electrodes, and since there are actually three such electrode groups,
Multi-arc spraying can be performed by using a plurality of arcs, which are three times as many as 27 arcs and arcs generated between the upper and lower electrode groups.

In the above-described embodiment or its modification, the plasma spraying section 300 has been described as an example in which the electrode group is composed of six or nine arc electrodes in a three-stage configuration. (a) is a plan view showing a plasma spraying apparatus according to a further modified example of such a configuration, in which 341 is six arc electrodes constituting one electrode group, 342 is a neutral electrode at the center thereof, and 343 is a neutral electrode. A working gas or a combustion gas is injected from this portion in the outer ring-shaped space surrounding the electrodes 341 and 342. Reference numeral 344 further denotes an outer ring-shaped space from which air or the like is jetted.

FIG. 8B shows another modification of the above embodiment. Here, reference numerals 341 and 342 denote the same parts as in FIG. 8A, and reference numeral 345 denotes a space surrounding the neutral electrode 342. One inert gas is injected. Reference numeral 346 denotes a space surrounding the outer six arc electrodes 341 from which the second inert gas is injected.

In the modification shown in FIG. 8, the electrode group consisting of six electrodes is one stage, but various gases can be injected from a predetermined gap as shown in FIG. Then, the advantages of both plasma flame and gas jet flow can be drawn out.

FIGS. 9A and 9B show a plasma spraying apparatus according to a second embodiment of the present invention, and the same reference numerals as those in FIGS. 1 and 2 denote the same parts. Here, two output terminals, that is, positive voltage output terminals 6a to 6c and a negative voltage output terminal 6a 'are used as the conversion unit in the configuration of FIG.
6c 'are provided separately from the respective output terminals of the converters 20a to 20c. The sawtooth wave on the positive side shown in FIG. 7A and the negative side shown in FIG. Is obtained.

More specifically, the first converter 20a will be described. 21a is a switch circuit having the same configuration as that of the first embodiment, 24a and 25a are positive and negative contacts of the switch circuit 21a, and 23a and 23a 'are switches. Diodes 22a, 22a,
Reference numeral 22a 'denotes a saturation reactor connected to each diode, and these constitute the conversion unit 20a. In addition,
The second and third converters 20b and 20c are also used in the first converter.
, Which have switches 22b and 22c having positive contacts 24b and 24c and negative contacts 25b and 25c, and diodes 23b and 23, respectively.
b ', 23c, 23c' and the saturated reactors 22b, 2
2b ', 22c and 22c'.

In this case, the arc electrodes 4-1, 4-3, 4-5 are connected to the positive output terminals 6a-6c, and the negative outputs 6a'-
The arc electrodes 4-4, 4-6, and 4-2 are connected to 6c '(see FIG. 9B). However, in this figure, the arc electrodes 4-1 to 4-6 constituting the first multi-arc electrode group 304 are shown.
Only the second and third multi-arc electrode groups are omitted because they have the same configuration. In this case, the maximum voltage difference between adjacent arc electrodes in one electrode group is larger than in the first embodiment, and the generated arc is stronger.

In each of the above embodiments, the case where the power supply unit has one DC power supply is shown. However, for example, three DC power supplies may be provided corresponding to each phase when outputting three-phase AC.

In the above description, a saturated reactor is shown as a reactance circuit. However, an LC circuit combining a saturated reactor and a capacitor may be used. In this case, a drooping characteristic can be sharpened.

The plasma spraying using the multi-arc can be applied not only to the plasma spraying apparatus shown in the first and second embodiments, but also to a spraying machine for repairing a lining of an industrial kiln. . Hereinafter, as a third embodiment of the present invention, a thermal spraying machine for repairing the lining of an industrial kiln will be described with reference to FIG.

FIG. 10 shows the overall configuration of a thermal spraying machine for repairing the lining of an industrial kiln. In the figure, reference numeral 400 denotes the thermal spraying machine, which is a power supply device 100 and a multi-electrode plasma arc generator 408.
and a thermal spray portion 408 having a. The multi-phase multi-electrode plasma arc generator 408a includes six graphite electrodes 401, 402, 403, 401A, 402A, 4
03A, and these six electrodes are arranged radially at equal angles (60 ° intervals) when viewed from above so as to form an inverted conical shape and converge at the electrode tip 409. I have. Each electrode can be advanced and retracted by an electrode feed mechanism (not shown), and is adjusted for electrode consumption. Here, the power supply device 100 has the same configuration as that of the first embodiment. And here, the power supply 10
0 output terminals 6a to 6c are provided with phase adjusters 406a to 406a for controlling the phase of each phase output to adjust the intensity of the arc.
406c is connected to the graphite electrodes 401 and 40.
1A is connected to the output terminal 6a via the phase adjustment device 406a.
The graphite electrodes 402 and 402A are connected to the phase adjuster 406b.
Are connected to the output terminals 6b through the graphite electrodes 403, 403.
A is connected to the output terminal 6c via the phase adjustment device 406c.

Reference numeral 410 denotes six graphite electrodes 401, 4
At the same time, a plurality of arcs can be obtained between 02, 403, 401A, 402A, and 403A, and at the same time, a non-transitional plasma arc 412 is obtained so as to be ejected downward at the electrode tip 409. SiO ₂ , Al
_The material to be sprayed 413, which is a mixture of ₂ O ₃ and CaO, is a charging port for supplying the material to be sprayed 412 during the multi-arc, and the material to be sprayed 412 charged into the charging port 413 is a fixed amount at the base. The supply device 414 supplies the gas from the charging pad 415 through the inlet pipe 416 to the center of the arc tip 409 from above. Reference numeral 421 denotes a refractory brick constituting an industrial kiln to be lined, and 422 denotes SiO ₂ , Al run lining the refractory brick 421.
_This is a running film made of a mixture of ₂ O ₃ and CaO.

The multi-arc generated by the present multi-phase multi-electrode plasma arc generator has the following features.

An ultra-high-temperature arc carrying negative electron ions is generated regardless of whether it is in air, liquid, or vacuum.

Since a heat source of 4000 ° C. or higher can be obtained at the same time when the switch is turned on, even a substance having a high melting point can be melted and dissolved.

Since a rotating magnetic field is generated at the tip of the electrode, an electric stirring effect on the irradiation target can be expected.

The number of phases and the number of electrodes can be increased by a multiple of 3, so that the electrode diameter can be increased and the load current can be increased to process a large-capacity substance in a short time.

A three-phase, six-phase, etc., polyphase alternating current is used, the total current of each phase is always 0, and no earth wire is required, so the arc is a non-transitional one that does not require a counter electrode such as a counter electrode. Therefore, it is not necessary to use a material other than metal as a counter electrode, so that a refractory having no conductivity can be directly heated, sintered, and melted. For example, this multi-arc is used for the combustion treatment of general industrial waste such as waste dry batteries and radioactive materials, and is used for cutting insulating concrete and stone materials when dismantling buildings and the like. And there are a variety of uses.

By providing a neutral electrode at the center of the plurality of electrodes, a stronger plasma arc is generated.

Instead of providing the above-described neutral electrode, a solvent, a gas, or the like can be released from the central portion.

Next, the operation will be described. Power supply 10
The 0 to 3 phase alternating current is supplied to the electrodes 401 and 401A and the electrode 40.
2,402A and the electrodes 403, 403A. At this time, it is better to apply the respective phase outputs of the power supply device 100 to the respective electrodes as they are, but when it is desired to adjust the strength of the arc or the like, the respective phase adjusters slightly control the phase of the respective phase outputs. . When a three-phase alternating current is applied to each of the electrodes, a plurality of arcs, ie, multi-arcs, are generated between the six electrodes, and the tip portions 409 of these electrodes are generated.
A more non-transitory plasma arc 410 is injected. In order to supply the material to be sprayed to the converging central portion of the multiple electrodes where the plasma arc is generated, the material to be sprayed 4
12 is supplied, the material to be sprayed 412 is supplied from the charging vessel 415 to the feed pipe 41 by the quantitative supply device 414 at the base.
6, is supplied from above to the center of the arc tip portion 409, is heated and melted at an extremely high temperature by the highest heat flow of the non-transferable plasma arc 410, and is injected toward the inner surface of the refractory brick 421. As a result, a lining film 422 is formed on the inner surface of the refractory brick 421. According to the spraying machine using the multi-arc, not only can CaO and the like be melted and fixed in only a few minutes, but also the lining lining has extremely good heat resistance and heat insulation properties, and has strong performance against rapid heat and rapid cooling. You can do it.

As described above, in this embodiment, since the power supply device having the same configuration as the power supply device of the first embodiment is used, the above-described first power supply device is used.
In addition to obtaining the effects of (1) to (4) of the embodiment, when performing thermal spraying for lining a refractory, thermal spraying is performed by using a multi-phase, multi-electrode, multi-arc generating means. It can be done reliably.

In order to form the lining film 422 on the entire inner surface of the refractory brick 421, thermal spraying may be performed while moving the multi-arc electrode. Alternatively, in some furnaces, the multi-arc electrode is fixed and the furnace is rotated. In any case, the spraying operation can be completed in about several minutes to several tens of minutes.

In the above description, an apparatus for performing plasma spraying using three-phase alternating current has been described. However, in the case where spraying is performed using only an arc flame without a rotating magnetic field, direct current or single-phase alternating current may be used. Good. For example, as a single-phase AC power supply, a phase control circuit that controls the supply of three-phase alternating current for each phase and a three-phase primary coil and a single-phase secondary side are wound around a single-phase iron core. A primary coil having a transformer connected to a three-phase AC power supply via the phase control circuit, and a power supply device for outputting a single-phase AC (Japanese Patent Application No. 2-150585) or the like can be used; .

[0069]

As described above, according to the plasma spraying apparatus of the present invention, a switch circuit capable of outputting a positive or negative voltage of a DC power supply intermittently or by switching between a positive and negative voltage and a switch circuit capable of outputting the same. A converter comprising a connected reactance circuit, and a control circuit for the switch circuit,
Since the power supply device that outputs the multi-phase AC is used, a DC power supply such as a battery can be used, and three-phase imbalance and a flicker phenomenon can be avoided. In addition, since a transformer is not required in the power supply device, there is an effect that the entire device can be reduced in size and weight.

Further, by changing the timing of opening / closing or switching in the switch circuit and changing the reactance component of the reactance circuit in the power supply device, it is possible to obtain various polyphase AC outputs having different waveforms and frequencies according to the materials. There is.

Further, since a multi-arc multi-electrode, for example, three or six arc electrodes is used for plasma spraying, there is an effect that a large-sized plasma jet can be obtained.

Further, a multi-arc is used for plasma spraying, a multi-arc electrode group consisting of three or six arc electrodes is arranged in a plurality of stages, and the arrangement of the arc electrodes in each stage is changed so that an arc is generated between the upper and lower electrode groups. The arc electrodes in the upper or lower electrode group are shifted little by little so that a rotating jet of plasma is generated by a strong rotating magnetic field, and a strong plasma spray can be performed. effective.

Further, according to the thermal spraying machine for repairing the lining of an industrial kiln according to the present invention, the power supply device having the above-described configuration is used, and each phase voltage of the power supply device is applied to each of the plurality of electrodes so that a plurality of electrodes are provided between the electrodes. A non-transferring plasma arc is ejected from the electrode tip by generating an arc, and the lining material is supplied into the non-transferring plasma arc, and the lining material is heated and melted by the non-transferring plasma arc. Since the thermal spraying is performed by irradiating the refractory material, a DC power source such as a battery can be used, and it is possible to avoid three-phase imbalance and a flicker phenomenon, to reduce the size and weight of the entire apparatus, and to perform thermal spraying. The effect is that the work can be performed very easily and reliably.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a plasma spraying apparatus according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a specific configuration of a plasma spraying section of the plasma spraying apparatus.

FIG. 3 is a view showing an arrangement of arc electrodes in a three-stage multi-electrode group in the plasma spraying section.

FIG. 4 is a view showing a specific configuration of a neutral electrode in the plasma spraying section.

FIG. 5 is a diagram for explaining an output waveform of a power supply device of the plasma spraying apparatus.

FIG. 6 is a view showing a modification in which the number, arrangement, and the like of the arc electrodes in the plasma spraying section of the plasma spraying apparatus are changed.

FIG. 7 is a diagram showing an output waveform in the modification.

FIG. 8 is a view showing another modified example in which a multi-electrode group has a single-stage configuration in a plasma spraying section of the plasma spraying apparatus.

FIG. 9 is a diagram showing an overall configuration of a plasma spraying apparatus and an arrangement of multiple electrodes according to a second embodiment of the present invention.

FIG. 10 is a view showing a thermal spraying machine for repairing lining of an industrial kiln according to a third embodiment of the present invention.

FIG. 11 is a view showing a conventional thermal spraying method for repairing the lining of an industrial kiln.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 DC power supply 2a-2c conversion part 4a-4c Arc electrode 6a-6c Output terminal 7 Neutral terminal 21a-21c Switch circuit 22a-22c Saturation reactor 31 Switch control circuit 100 Power supply device 300, 300 'Thermal spray part

Claims (4)

(57) [Claims] 1. A plasma spraying apparatus comprising: a power supply device for outputting a polyphase alternating current; and a plasma spraying unit for receiving the power supply and performing plasma spraying, wherein the power supply device is connected to positive and negative voltages of a DC power supply. A switch circuit having positive and negative contacts and capable of opening and closing the positive and negative contacts, or switching between the positive and negative contacts, and having a reactance component and connected to the switch circuit. A plurality of converters for converting DC into AC, a neutral terminal connected to an intermediate potential between positive and negative voltages of the DC power supply, and opening and closing or switching operations of switch circuits of the respective converters. A control circuit for sequentially performing switching control with a predetermined time difference, for outputting a multi-phase alternating current between a neutral terminal and an output terminal of each converter. A plurality of arc electrodes having a neutral electrode connected to a neutral terminal and generating a multi-arc around the neutral electrode corresponding to the number of phases of the polyphase alternating current are arranged uniformly on the same circumference. A plasma spraying apparatus having one or more stages of a multi-arc electrode group as described above, wherein each of the plurality of arc electrodes is connected to an output terminal of a corresponding phase converter. 2. The power supply device has first to third conversion units, and the control circuit has a phase difference of 1/3 of one cycle of an output waveform obtained by one switching of a switch circuit. Each of the switch circuits is configured to perform switching control, and the plasma spraying unit arranges a multi-arc electrode group including three or six arc electrodes in a plurality of stages in a vertical direction, and arranges the arc electrodes in each stage. 2. The plasma spraying apparatus according to claim 1, wherein the arrangement of the arc electrodes of the upper and lower electrode groups is slightly shifted so that an arc is generated between the upper and lower electrode groups. 3. The plasma spraying apparatus according to claim 2, wherein the power supply device is configured to change the reactance component of the reactance circuit based on a reactance control signal, and to control the control circuit with a timing control signal. And the switching operation of the positive and negative contacts in the switch circuit and the timing of the switching operation between the positive and negative contacts are changed based on the one of the reactance control signal and the timing control signal. A plasma spraying apparatus characterized in that one or both of the shape of the output waveform and the frequency of the AC output are made variable over time by both of them. 4. A thermal spraying machine for repairing a lining of an industrial kiln, comprising: a power supply device for outputting a polyphase alternating current; and a spraying portion for receiving the power output and performing thermal spraying for lining a refractory lining. The device has a positive and negative contact connected to the positive and negative voltages of the DC power supply, and a switch circuit capable of opening and closing the positive and negative contacts or switching between the positive and negative contacts. A reactance circuit having a reactance component and connected to the switch circuit, a plurality of converters for converting DC to AC, and a neutral terminal connected to an intermediate potential between the positive and negative voltages of the DC power supply, A control circuit for sequentially switching control of the switch circuits of the conversion units with a predetermined time difference, and outputs a polyphase alternating current between a neutral terminal and an output terminal of each conversion unit.
The spraying unit is configured to apply a phase voltage of the power supply to each of the plurality of electrodes to generate a plurality of arcs between the electrodes, and to eject a non-transitional plasmic arc from the electrode tip. An arc generator and a means for supplying a material for lining lining into the non-migratory plasma arc, wherein the material for lining is heated and melted by the non-migratory plasma arc to irradiate a refractory to perform thermal spraying. A thermal spraying machine for repairing linings in industrial kilns.