JP2016068058A - Fine particle generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine particle generation device, capable of preventing damage to a counter electrode due to plasma, with respect to a technique for generation of fine particles using a plasma torch.SOLUTION: A fine particle generation device according to the invention is configured so that transition type plasma P1 generated between a transition type plasma electrode 1 and a counter electrode 10 rotates by a magnet 3, and by the rotating transition type plasma P1, a raw material is vaporized and passes through a penetration part 20 of the counter electrode 10, and then is cooled in a fine particle generation cooling chamber 70 to generate fine particles. A side surface part of the counter electrode 10 facing the penetration part 20 is an insulation body 10A.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a fine particle generator using a plasma torch.

  Techniques relating to plasma torches have existed conventionally (for example, Patent Document 1 and Patent Document 2).

  In the technique according to Patent Document 1, titanium / iron raw material coarse particles having a predetermined weight ratio are vaporized by melting and evaporating them at a high temperature such as high-frequency thermal plasma to form a superfine composite oxide of titanium / iron. Is generated and collected.

  Further, in the technique according to Patent Document 2, the plasma torch includes a ring cathode, an anode disposed so as to surround the discharge space between the discharge portion of the ring cathode, and a central axis in the discharge space. It is comprised from the magnet installed so that the magnetic flux which cross | intersects in a surface may be formed, and the thermal spray material supply port pipe which sends in a thermal spray material.

  In addition to Patent Document 1, Patent Document 3 and Patent Document 4 exist as conventional techniques related to fine particle production using plasma.

  In the technique according to Patent Document 3, metal powder and boron powder are supplied into a thermal plasma of an inert gas such as argon gas to obtain nano-order metal boride fine powder.

  Moreover, in the technique which concerns on patent document 4, a carbon crucible is made to hold | maintain an inorganic lump, arc plasma is generated, and a SiC nanoparticle is manufactured.

  Patent Document 5 exists from the viewpoint of downsizing the entire torch, high energy efficiency, and uniform heating of the raw material.

  The fine particle generation apparatus according to Patent Document 5 includes a direct current plasma torch, a counter electrode disposed opposite to the direct current plasma torch, and a wall portion surrounding the material vaporization reaction chamber from the side surface side. The DC plasma torch has a ring-shaped magnet, a cylindrical shape, a transitional plasma electrode in which the magnet is disposed inside a cylindrical cavity, and is separated from the magnet by a predetermined distance, and a substantially central portion of the DC plasma torch. And a raw material passage portion provided in the housing.

JP-A-6-115942 JP-A-8-319552 JP 2003-261323 A JP 2010-95442 A JP 2012-40520 A

  In the technique according to Patent Document 5, the distance between the DC plasma torch and the counter electrode may be increased in order to squeeze the plasma and increase the evaporation efficiency. In this case, the radial magnetic field is weak in the through electrode region of the counter electrode. Therefore, the plasma stays in the penetrating part or the like, which may damage the counter electrode.

  Therefore, an object of the present invention is to provide a fine particle generation apparatus capable of preventing damage to the counter electrode due to plasma in a technique related to the generation of fine particles using a plasma torch.

  In order to achieve the above object, a fine particle generation apparatus according to the present invention includes a direct current plasma torch and a counter electrode disposed facing and spaced from the direct current plasma torch, the direct current plasma torch includes: A ring-shaped magnet, a cylindrical shape, the magnet is disposed inside the hollow of the cylinder, and is separated from the magnet by a predetermined distance; and a substantially central portion of the DC plasma torch A material material passage portion through which the material material passes, and the counter electrode has a ring shape in plan view from the DC plasma torch side, and the ring-shaped through portion of the counter electrode A transition type plasma generated between the transition type plasma electrode and the counter electrode is further provided with a particulate generation cooling chamber that is in communication with the surroundings and is cooled. The raw material material output from the raw material material passage portion is vaporized by the rotating transfer plasma rotated by the magnet, and is cooled in the fine particle production cooling chamber through the through portion. And a side surface portion of the counter electrode facing the through portion is an insulator.

  The fine particle generation apparatus according to the present invention includes a direct current plasma torch and a counter electrode disposed to face and separate from the direct current plasma torch. The direct current plasma torch has a ring-shaped magnet and a cylindrical shape. A transitional plasma electrode in which the magnet is disposed inside the cylindrical cavity and spaced apart from the magnet by a predetermined distance; and a raw material through which the raw material material is provided at a substantially central portion of the DC plasma torch. A material passage portion, and the counter electrode has a ring shape in plan view from the DC plasma torch side, and communicates with the ring-shaped through portion of the counter electrode. The particle generation cooling chamber is further provided, and the transfer type plasma generated between the transfer type plasma electrode and the counter electrode is rotated by the magnet. The raw material material output from the raw material material passage portion is vaporized by the rotating transfer plasma, and is cooled in the fine particle production cooling chamber through the through-hole to generate fine particles. The side part facing the penetrating part is an insulator.

  Therefore, it is possible to prevent the migration type plasma from being irradiated and staying on the side surface portion of the counter electrode facing the penetrating portion. Therefore, damage to the counter electrode due to the stay of the transfer plasma can be prevented.

1 is a diagram illustrating an overall configuration of a fine particle generation device 100 according to the present invention. It is an expanded sectional view which shows the structure of the front-end | tip part vicinity of the DC plasma torch 50 to which the positive voltage is applied. FIG. 3 is a diagram showing a state of magnetization of a magnet 3. It is sectional drawing for demonstrating generation | occurrence | production of transfer type plasma P1, and rotation of the said transfer type plasma P1. It is a figure which shows a mode that the plasma power supply 61 applies a reverse polarity voltage in a microparticle production | generation apparatus. It is a figure which shows the state which the direct-current plasma torch 50 and the counter electrode 10 adjoin. It is a figure which shows the state which the DC plasma torch 50 and the counter electrode 10 have left | separated. 2 is an enlarged cross-sectional view illustrating a configuration of a counter electrode 10 according to Embodiment 1. FIG. 4 is an enlarged cross-sectional view illustrating a configuration of a counter electrode 10 according to Embodiment 2. FIG. 4 is an enlarged plan view showing a configuration of a counter electrode 10 according to Embodiment 2. FIG. 6 is an enlarged cross-sectional view showing a configuration of a counter electrode 10 according to Embodiment 3. FIG. 6 is an enlarged cross-sectional view showing another configuration of the counter electrode 10 according to Embodiment 3. FIG.

  First, the fine particle generation apparatus which is the premise of the present invention will be described in detail.

  FIG. 1 is a diagram illustrating an overall configuration of the fine particle generation apparatus 100. As shown in FIG. 1, the particle generation device 100 includes a DC plasma torch 50. FIG. 2 is an enlarged cross-sectional view showing the configuration in the vicinity of the tip of the DC plasma torch 50 shown in FIG.

  As shown in FIG. 1, the particulate generator 100 includes a DC plasma torch 50, a vacuum pump 60, a plasma power supply 61, a cooling water supply unit 62, a first plasma gas supply unit 63, a second plasma gas supply unit 64, A plasma torch elevating mechanism 65, a powder material supply unit 66, a gas supply unit 67, a particle generation cooling chamber 70, a particle trapping chamber 71, a particle trapping filter 72, and a heat exchanger 73 are provided. Furthermore, as shown in FIG. 2, the fine particle generation device 100 also includes a counter electrode 10, a wall surface portion 11, and a plurality of insulators 12 and 13.

  The configuration of the circled region shown in FIG. 1 (that is, the configuration near the tip of the DC plasma torch 50) is shown in FIG. As shown in FIG. 2, the DC plasma torch 50 includes a transitional plasma electrode 1, an inner cylinder 2, a magnet 3, an outer cylinder 4, and a plurality of insulators 5 and 6. In addition, as shown in FIG. 2, these members 1-6 are all arrange | positioned in the plasma torch front-end | tip part.

<Configuration of DC plasma torch and its surroundings>
First, the configuration of the DC plasma torch 50 will be described.

  The transfer plasma electrode 1, the inner cylinder 2, and the outer cylinder 4 each have a cylindrical shape and are made of a conductive material. The transfer plasma electrode 1 surrounds the inner cylinder 2 with a predetermined distance. That is, the cylindrical diameter of the transfer plasma electrode 1 is larger than the cylindrical diameter of the inner cylinder 2. The outer cylinder 4 surrounds the transfer type plasma electrode 1 with a predetermined distance. That is, the cylindrical diameter of the outer cylinder 4 is larger than the cylindrical diameter of the transitional plasma electrode 1.

  In the cavity of the outer cylinder 4, the inner cylinder 2 and the transfer type plasma electrode 1 are arranged, and in the cavity of the transfer type plasma electrode 1, the inner cylinder 2 is arranged. Here, the cylindrical central axis of the transfer type plasma electrode 1, the cylindrical central axis of the inner cylinder 2, and the cylindrical central axis of the outer cylinder 4 coincide with each other. The central axis is illustrated as the central axis AX in FIG.

  In the following description, the direction of the central axis AX is referred to as “axial direction”. The direction of the cylindrical diameter of each member 1, 2, 4 is referred to as “radial direction”.

  The cavity of the inner cylinder 2 functions as a raw material passage portion 25 through which the raw material passes, and is present at a substantially central portion of the DC plasma torch 50. Further, the space formed between the inner cylinder 2 and the transitional plasma electrode 1 functions as a gas passage portion 26 through which the plasma gas passes. The space formed between the transfer plasma electrode 1 and the outer cylinder 4 functions as a gas passage portion 27 through which the plasma gas passes.

  The magnet 3 is a permanent magnet having a ring shape. The ring-shaped central axis of the magnet 3 also coincides with the central axis AX. The magnet 3 is magnetized in the direction of the central axis AX. Specifically, in the ring-shaped magnet 3, the upper part (raw material supply side) is the “N pole” and the lower part (side facing the counter electrode 10) is the “S pole”.

  The transfer plasma electrode 1 surrounds the magnet 3 with a predetermined distance. That is, the magnet 3 is disposed inside the cylindrical cavity of the transfer plasma electrode 1. In the form shown in FIG. 2, the magnet 3 is disposed (built in) inside the inner cylinder 2. More specifically, the magnet 3 is disposed on the counter electrode 10 arrangement side (near the bottom of the inner cylinder 2) inside the inner cylinder 2. That is, the magnet 3 is disposed at a position closer to the counter electrode 10.

  As shown in FIG. 2, the insulator 5 is formed so as to cover the bottom side end of the inner cylinder 2. Further, an insulator 6 is disposed on the side surface portion of the outer cylinder 4 facing the transfer plasma electrode 1.

  Here, the DC plasma torch 50 having the above configuration can move in the vertical direction in FIG. In other words, the DC plasma torch 50 is movable in the direction facing the counter electrode 10.

  Now, as shown in FIG. 2, the counter electrode 10 is provided on the plasma output side of the DC plasma torch 50 so as to be separated from and opposed to the DC plasma torch 50.

  The counter electrode 10 has a ring shape in plan view from the DC plasma torch 50 side. Accordingly, the ring-shaped through portion 20 of the counter electrode 10 communicates with the material vaporization reaction chamber 35 on one side, and communicates with the particulate generation cooling chamber 70 on the other side. Therefore, the material vaporization reaction chamber 35 and the fine particle generation cooling chamber 70 are connected via the penetrating portion 20.

  The ring-shaped central axis of the counter electrode 10 substantially coincides with the central axis AX. Further, the ring-shaped outer diameter D4 of the counter electrode 10 is equal to or smaller than the outer diameter D1 of the transfer plasma electrode 1 (D4 ≦ D1). Further, the inner diameter D3 of the ring shape of the counter electrode 10 is smaller than the inner diameter D2 of the transfer plasma electrode 1 (D3 <D2). Further, as shown in FIG. 2, the surface of the counter electrode 10 facing the DC plasma torch 50 moves from the ring-shaped inner diameter side of the counter electrode 10 toward the outer diameter side of the ring shape in a cross-sectional view. , Having a shape inclined in a direction away from the DC plasma torch 50.

  Now, as shown in FIG. 2, a material vaporization reaction chamber 35 is formed between the DC plasma torch 50 and the counter electrode 10. The wall surface portion 11 is formed so as to surround the material vaporization reaction chamber 35 from the side surface side.

  The material vaporization reaction chamber 35 is formed by the DC plasma torch 50, the counter electrode 10, the upper wall surface of the particulate generation cooling chamber 70 and the wall surface portion 11 except for the penetration portion 20, the raw material passage portion 25 and the gas passage portions 26 and 27. Airtightness is maintained (sealed).

  The wall surface portion 11 has a torch contact portion 15 connected so as to be fixed by a fixing member b1. The torch contact portion 15 is in contact with the side surface portion of the DC plasma torch 50. Here, a groove is partially formed in the torch contact portion 15, and an O-ring 16 is disposed in the groove. The torch contact portion 15 functions as a receiver for the above-described up-and-down movement of the DC plasma torch 50, and the airtightness of the up-and-down material vaporization reaction chamber 35 is maintained by the arrangement of the O-ring 16.

  Further, as shown in FIG. 2, the bottom surface portion facing the material vaporization reaction chamber 35 excluding the counter electrode 10 (that is, a part of the upper wall surface of the fine particle generation cooling chamber 70 facing the material vaporization reaction chamber 35) is insulated. An object 13 is formed. Further, an insulator 12 is formed on the wall surface portion 11 facing the material vaporization reaction chamber side 35.

<Configuration of microparticle generator>
The plasma torch raising / lowering mechanism 65 is disposed above the DC plasma torch 50 and performs the above-described up / down movement of the DC plasma torch 50. The plasma power supply 61 supplies direct current power to the transfer plasma electrode 1 and the counter electrode 10. The example shown in FIG. 2 shows a state of power supply at the time of positive polarity (that is, a case where a negative voltage is applied to the transfer plasma electrode 1 and a positive voltage is applied to the counter electrode 10).

  The cooling water supply unit 62 supplies a refrigerant (hereinafter, described as an example of cooling water) to each of the DC plasma torch 50, the particulate generation cooling chamber 70, and the heat exchanger 73.

  Further, the cooling water supply unit 62 supplies the cooling water so that the cooling water circulates in the upper part, the side part and the bottom part (wall surface of the fine particle production cooling chamber 70) of the fine particle production cooling chamber 70, and in the counter electrode 10. Supply.

  The first plasma gas supply unit 63 supplies plasma gas to the material vaporization reaction chamber 35 through the outside of the source gas material passage unit 25 in the DC plasma torch 50. Specifically, the first plasma gas supply unit 63 supplies the plasma gas to the material vaporization reaction chamber 35 through the gas passage portion 27 formed between the outer cylinder 4 and the transitional plasma electrode 1. To do. Here, as shown in FIG. 1, as the plasma gas supplied by the first plasma gas supply unit 63, an inert gas (argon, helium, etc.) and / or a reactive gas (oxygen molecule, Nitrogen molecules, etc.) can be employed.

  The second plasma gas supply unit 64 supplies the plasma gas to the material vaporization reaction chamber 35 through the outside of the source gas material passage unit 25 in the DC plasma torch 50. Specifically, the second plasma gas supply unit 64 supplies the plasma gas to the material vaporization reaction chamber 35 through the gas passage unit 26 formed between the inner cylinder 2 and the transitional plasma electrode 1. To do. Here, as shown in FIG. 1, as the plasma gas supplied by the second plasma gas supply unit 64, an inert gas (argon, helium, etc.) and / or a reactive gas (oxygen molecule, Nitrogen molecules, etc.) can be employed.

  The powder material supply unit 66 stores a powder material as a raw material. The powder material is a powder (powder) having a particle size of 100 μm or less. The carrier gas is supplied from the gas supply unit 67 to the powder material supply unit 66. The powder material output from the powder material supply unit 66 is carried by the carrier gas, and is supplied to the material vaporization reaction chamber 35 through the raw material material passage unit 25.

  A transfer type plasma P1 is generated between the transfer type plasma electrode 1 and the counter electrode 10 in the material vaporization reaction chamber 35 by the power supply from the plasma power supply 61 and the plasma gas supply from the plasma gas supply parts 63 and 64. To do. As will be described later, the transfer plasma P1 is affected by the magnetic force from the magnet 3 (more specifically, the radial magnetic force), so that the transition plasma P1 has a central axis AX in the material vaporization reaction chamber 35. Rotate around. That is, the transfer type plasma P1 is generated between the transfer type plasma electrode 1 and the counter electrode 10 in the material vaporization reaction chamber 35 so as to form a cylindrical shape around the central axis AX. . One end of the cylinder is the end of the transfer plasma electrode 1, and the other end of the cylinder is the upper surface of the counter electrode 10.

  Further, the powder material supplied from the powder material supply unit 66 is heated in the material vaporization reaction chamber 35 by the rotational plasma P1 in the rotating state. The powder material is vaporized in the material vaporization reaction chamber 35 by the heating.

  The fine particle generation cooling chamber 70 is formed by being surrounded by a conductive member (wall surface). As described above, the cooling water circulates on the wall surface of the particulate generation cooling chamber 70, and the wall surface of the particulate generation cooling chamber 70 and the interior of the particulate generation cooling chamber 70 are cooled by the circulation of the cooling water. . Further, by applying a voltage from the plasma power source to the wall surface of the particle generation cooling chamber 70, the voltage is applied to the counter electrode 10 connected to the wall surface of the particle generation cooling chamber 70. As described above, the fine particle generation cooling chamber 70 is connected to the material vaporization reaction chamber 35 through the penetrating portion 20. In addition, the particle generation / cooling chamber 70 is connected to the particle capturing chamber 71 on the side surface.

  The vacuum pump 60 is used to lower the atmospheric pressure in the particle generation / cooling chamber 70, the particle trapping chamber 71 and the heat exchanger 73. The powder material (hereinafter, vaporized material) vaporized in the material vaporization reaction chamber 35 using the pressure difference generated by the vacuum pump 60 and the air supply valve passes through the through portion 20 to generate fine particles. It moves to the cooling chamber 70, and further moves to the particle trapping chamber 71 through the particle generation / cooling chamber 70.

  In the fine particle generation cooling chamber 70, the vaporized material is cooled and condensed to generate ultrafine particles (nanoparticles). The ultrafine particles generated in the fine particle generation cooling chamber 70 are sent to the fine particle capturing chamber 71. The particulate trapping filter 72 is in a suction state through the heat exchanger 73, and the ultrafine particles are collected by the particulate trapping filter 72 in the suction state. The gas or the like that has passed through the particulate trapping filter 72 is sufficiently cooled in the heat exchanger 73.

<Method for producing ultrafine particles in fine particle production apparatus>
Next, the operation in the fine particle generation apparatus 100 will be described.

  As shown in FIGS. 1 and 2, using a plasma power source 61, for example, a positive DC power source is applied between the transfer plasma electrode 1 and the counter electrode 10. Further, the first plasma gas supply unit 63 supplies the plasma gas to the material vaporization reaction chamber 35 through the gas passage unit 27. The second plasma gas supply unit 64 supplies the plasma gas to the material vaporization reaction chamber 35 through the gas passage unit 26.

  Then, the transfer type plasma P1 is generated between the transfer type plasma electrode 1 and the counter electrode 10, and the transfer type plasma P1 is rotated by the action of the magnetic field of the magnet 3 to become a cylindrical plasma (FIG. 2). Here, due to the presence of the insulators 5 and 6, the transfer type plasma P1 is generated between the electrodes 1 and 10, that is, in a region where the magnetic field of the magnet 3 in the radial direction is larger than the magnetic field of the magnet 3 in the axial direction. Is done.

  As described above, the transfer plasma P <b> 1 rotates about the central axis AX by the magnetic field generated by the magnet 3. Specifically, it is as follows.

  As shown in FIG. 2, the ring-shaped magnet 3 is built in the inner cylinder 2, but the magnet 3 is magnetized in the direction of the central axis AX as shown in FIG. Therefore, the magnetic field MF shown in FIG. 4 is formed by the magnet 3 at the tip of the DC plasma torch 50.

  When a positive DC voltage having a positive polarity is applied between the transfer plasma electrode 1 and the counter electrode 10 under the generation of the magnetic field MF, transfer plasma P1 is generated. Further, a transitional plasma arc current I1 flows from the counter electrode 10 toward the transitional plasma electrode 1 (see FIG. 4).

  Here, due to the presence of the insulators 5 and 6, the transfer type plasma arc current I 1 flows only between the counter electrode 10 and the end (bottom part) of the transfer type plasma electrode 1 facing the counter electrode 10. The formation of the insulators 12 and 13 can prevent the transfer type plasma arc current I1 from transferring to the other wall surface of the material vaporization reaction chamber 35.

  Therefore, as shown in FIG. 4, according to Fleming's left-hand rule, the transitional plasma P1 exerts a force F1 around the central axis AX due to the influence of the magnetic field B1 in the radial direction. Therefore, the transfer type plasma P1 rotates clockwise around the central axis AX. The magnitude of the force F1 is the radial magnetic field B1 × the transfer type plasma arc current I1. Thus, the transfer type plasma P1 always rotates.

  Now, in a state where the rotating transfer type plasma P1 is generated, the powder material supply unit 66 supplies the powdery powder material into the material vaporization reaction chamber 35 through the raw material material passage unit 25. To do. Here, the powder material is, for example, a powder having a particle size of 100 μm or less, and is supplied into the material vaporization reaction chamber 35 on the carrier gas.

  The raw material passage portion 25 extends along the central axis AX. Therefore, the powder material that has passed through the raw material passage portion 25 is supplied into the rotating interior of the transfer type plasma P1 that is rotating around the central axis AX. The powder material is heated and vaporized by the transfer type plasma P1 while moving inside the rotation of the transfer type plasma P1 toward the counter electrode 10.

  By the way, as described above, the distance between the electrodes 1 and 10 can be changed by the plasma torch elevating mechanism 65 to change the volume of the material vaporization reaction chamber 35. Thereby, with respect to powder material and gas, the amount of heating of heating by transfer type plasma P1 and a heating time can be adjusted.

  For example, when vaporizing a powder material that is difficult to vaporize, the distance between the electrodes 1 and 10 is increased to increase the volume of the material vaporization reaction chamber 35. Thereby, the heating amount and the heating time of the transfer type plasma P1 for the powder material can be increased. On the other hand, when vaporizing a powder material that easily vaporizes, the distance between the electrodes 1 and 10 is shortened, and the volume of the material vaporization reaction chamber 35 is reduced. Thereby, the heating amount and heating time of the transfer type plasma P1 for the powder material can be reduced. That is, by changing the distance between the electrodes 1 and 10 and changing the volume of the material vaporization reaction chamber 35 in accordance with the type of powder material, useless heat treatment by the transfer plasma P1 can be prevented. In other words, the powder material can be efficiently vaporized.

  The raw material vaporized in the material vaporization reaction chamber 35 enters the fine particle generation cooling chamber 70 through the penetration portion 20. In the fine particle generation cooling chamber 70, the vaporized raw material, carrier gas, plasma gas, reaction product vaporized substance, and the like are cooled and condensed and solidified to form ultrafine particles (nanoparticles).

  The ultrafine particles generated in the fine particle generation / cooling chamber 70 enter the fine particle capture chamber 71 connected to the fine particle generation / cooling chamber 70. Then, the ultrafine particles are sucked and collected by the fine particle capturing filter 72 installed in the fine particle capturing chamber 71. Here, as described above, the particulate trapping filter 72 is sucked by the vacuum pump 60 via the heat exchanger 73.

  Note that the plasma torch lifting mechanism 65 moves the DC plasma torch in a direction facing the counter electrode 10 before or after the generation of the transfer plasma P1 (during generation). That is, the distance between the transfer type plasma electrode 1 and the counter electrode 10 changes short and long, whereby the volume of the material vaporization reaction chamber 35 increases or decreases.

  In the above description, the plasma power supply 61 is referred to when positive voltage application is performed. That is, the plasma power source 61 applied “plus” to the counter electrode 10, “minus” to the transfer plasma electrode 1, and applied a predetermined voltage value between the electrodes 1 and 10. However, the plasma power supply 61 may apply a reverse polarity voltage. For example, as shown in FIG. 5, the plasma power supply 61 applies “minus” to the counter electrode 10, “plus” to the transfer plasma electrode 1, and applies a predetermined voltage value between the electrodes 1 and 10. May be.

  As described above, in the fine particle generation device 100, the volume of the material vaporization reaction chamber 35 is changed by changing the distance between the DC plasma torch 50 and the counter electrode 10. Therefore, the length of the transfer type plasma P1 generated between the DC plasma torch 50 and the counter electrode 10 can be varied. Therefore, the volume of the material vaporization reaction chamber 35 can be varied according to the type of raw material (powder material). Therefore, it is possible to always optimize the heating by the transfer plasma P1 according to the type of the raw material (powder material). That is, the optimum thermal efficiency can be set.

  For example, in a raw material that is difficult to vaporize, a relatively large heating time and heating amount by the transfer plasma P1 are required. Therefore, in this case, in order to prevent the application of the extra heating time and heating amount, and to enable the application of the minimum necessary heating time and heating amount, the plasma torch elevating mechanism 65 directs the direct current to the appropriate position. The plasma torch 50 is moved away from the counter electrode 10.

  However, when the DC plasma torch 50 is moved away from the counter electrode 10, the following problem occurs.

  For example, from the state shown in FIG. 6 (the state where the distance between the DC plasma torch 50 and the counter electrode 10 is small) to the state shown in FIG. 7 (the state where the distance between the DC plasma torch 50 and the counter electrode 10 is large). Suppose that it has changed. Here, the state of the magnetic field generated by the magnet 3 is also shown on the right side of FIGS.

  In the state of FIG. 7, the magnetic field is weak in the vicinity of the counter electrode 10 between the DC plasma torch 50 and the counter electrode 10. Further, in the vicinity of the counter electrode 10 (particularly, the penetrating portion 20 of the counter electrode 10), the radial magnetic field is weak (the radial component magnetic field is small). Therefore, the transfer type plasma P1 on the counter electrode 10 has a low rotation speed, a small rotation diameter, and stays in the vicinity of the through portion 20. Due to the stay in the vicinity of the penetration part 20 of the transfer type plasma P1, the counter electrode 10 becomes high temperature, melts and is damaged in the stay region. Here, in the case of reverse polarity, since the counter electrode 20 becomes a cathode, the damage is severe.

  In addition, in the state of FIG. 6, since the magnet 3 exists in the vicinity of the counter electrode 10, a magnetic field is strong also in the vicinity of the counter electrode 10. Therefore, the stay in the vicinity of the penetration part 20 of the transfer type plasma P1 can be suppressed.

  The purpose of the present invention is to suppress damage to the counter electrode 10 caused by the transfer plasma P1, and the present invention will be specifically described below with reference to the drawings showing embodiments thereof.

<Embodiment 1>
FIG. 8 is an enlarged cross-sectional view showing the configuration of the counter electrode 10 in the present embodiment. Note that the configuration of the fine particle generation apparatus 100 other than the configuration of the counter electrode 10 is the same as that described above, and a description thereof is omitted here.

As shown in FIG. 8, the entire side surface portion of the counter electrode 10 facing the penetrating portion 20 is composed of an insulator 10 </ b> A. The insulator 10A is preferably heat resistant. For example, SiN ₄ or BN can be employed as the insulator 10A.

  Although the radial magnetic field is very weak in the penetrating portion 20, the transitional plasma P <b> 1 is irradiated to a region other than the insulator 10 </ b> A of the counter electrode 10 by employing the counter electrode 10 shown in FIG. 8. That is, the counter electrode 10 other than the through portion 20 is irradiated. Therefore, it is possible to prevent the migration type plasma P <b> 1 from being irradiated and staying at the side surface portion of the counter electrode 10 facing the penetrating portion 20, and to prevent the counter electrode 10 from being damaged.

  In addition, although it irradiates to the counter electrodes 10 other than the penetration part 20, the radial magnetic field is stronger than the inside of the penetration part 20 in the area | region of the said irradiation. Therefore, compared with the inside of the penetration part 20, in the said irradiation area | region, the rotational speed of the transfer type plasma P1 becomes quick, a rotation diameter becomes small, and an irradiation area also increases. Accordingly, the influence of the transfer plasma P1 is small in the irradiation region of the counter electrode 10.

<Embodiment 2>
FIG. 9 is an enlarged cross-sectional view showing the configuration of the counter electrode 10 in the present embodiment. Note that the configuration of the fine particle generation apparatus 100 other than the configuration of the counter electrode 10 is the same as that described above, and a description thereof is omitted here.

  As shown in FIG. 9, the entire side surface portion of the counter electrode 10 facing the penetrating portion 20 is composed of an insulator 10 </ b> A. Further, in the present embodiment, the insulator 10A is also formed on a part of the surface of the counter electrode 10 facing the DC plasma torch 50. That is, the insulator 10 </ b> A is formed from the side surface portion of the counter electrode 10 facing the penetrating portion 20 to a part of the upper surface of the counter electrode 10 facing the DC plasma torch 50.

  FIG. 10 is an enlarged plan view of the counter electrode 10 viewed from the DC plasma torch 50 side. As shown in FIG. 10, the insulator 10 </ b> A is formed in an annular shape in the edge region on the through electrode 20 side of the counter electrode 10. That is, on the upper surface of the counter electrode 10 facing the DC plasma torch 50, the insulator 10A is formed from the inner peripheral end of the counter electrode 10 toward the outer peripheral end of the counter electrode 10 over a predetermined distance L1. Has been.

In the present embodiment also, it is desirable that the insulator 10A has heat resistance. For example, SiN ₄ or BN can be employed as the insulator 10A.

  By adopting the counter electrode 10 according to the present embodiment, in addition to the effects described in the first embodiment, there are the following effects.

  That is, when a voltage of reverse polarity is applied and the distance from the DC plasma torch 50 side to the counter electrode 10 is long, the transition type is also present in the vicinity of the through-hole 20 on the upper surface of the counter electrode 10 facing the DC plasma torch 50. Plasma P1 stays. And the damage of the counter electrode 10 generate | occur | produces by the stay of the said transfer type plasma P1.

  Therefore, in the counter electrode 10 according to the present embodiment, the insulator 10A includes not only the side surface portion of the counter electrode 10 facing the through portion 20 but also the through portion 20 on the upper surface of the counter electrode 10 facing the DC plasma torch 50. It is also formed in the vicinity. Therefore, it is possible to prevent the transfer type plasma P1 from being irradiated and staying in the vicinity of the penetrating portion 20 on the upper surface of the counter electrode 10 facing the DC plasma torch 50 and to prevent the counter electrode 10 from being damaged.

  Note that the transfer type plasma P <b> 1 is stay-irradiated in a region other than the vicinity of the through portion 20 on the upper surface of the counter electrode 10 facing the DC plasma torch 50. However, in the irradiation region, the radial magnetic field is stronger than in the through portion 20. Therefore, compared with the upper surface of the counter electrode 10 in the vicinity of the penetrating portion 20, in the irradiation region, the rotational speed of the transfer plasma P1 is increased, the rotation diameter is increased, and the irradiation area is also increased. Accordingly, the influence of the transfer plasma P1 is small in the irradiation region of the counter electrode 10.

<Embodiment 3>
FIG. 11 is an enlarged cross-sectional view showing the configuration of the counter electrode 10 in the present embodiment. Note that the configuration of the fine particle generation apparatus 100 other than the configuration of the counter electrode 10 is the same as that described above, and a description thereof is omitted here.

  As shown in FIG. 11, the entire side surface portion of the counter electrode 10 facing the penetrating portion 20 is composed of an insulator 10 </ b> A. Furthermore, in the present embodiment, the insulator 10 </ b> A protrudes from the lower surface of the counter electrode 10 on the fine particle generation cooling chamber 70 side. That is, the insulator 10 </ b> A formed on the side surface portion of the counter electrode 10 facing the through portion 20 protrudes below the counter electrode 10.

In the present embodiment also, it is desirable that the insulator 10A has heat resistance. For example, SiN ₄ or BN can be employed as the insulator 10A.

  By adopting the counter electrode 10 according to the present embodiment, in addition to the effects described in the first embodiment, there are the following effects.

  That is, when the amount of gas flowing through the through portion 20 is large, the transfer plasma P1 passes through the through portion 20 and wraps around the lower surface side of the counter electrode 10 facing the fine particle generation cooling chamber 70, and reaches the lower surface. Irradiate. When the transfer type plasma P1 is irradiated on the lower surface of the counter electrode 10 at a place where the radial magnetic field is weak, the transfer type plasma P1 stays in the irradiation region. And the damage of the counter electrode 10 generate | occur | produces by the stay of the said transfer type plasma P1.

  Therefore, in the counter electrode 10 according to the present embodiment, the insulator 10A formed on the side surface portion of the counter electrode 10 facing the penetrating portion 20 is more than the lower surface of the counter electrode 10 facing the fine particle generation cooling chamber 70. It is formed protruding. Therefore, it is possible to prevent the transfer type plasma P1 from entering the lower surface side of the counter electrode 10 facing the fine particle generation cooling chamber 70, and to prevent the transfer type plasma P1 from being irradiated and staying on the lower surface. 10 damage can be prevented.

  In the configuration example of FIG. 11, the insulator 10A is protruded toward the fine particle generation cooling chamber 70 in the configuration example shown in FIG. However, the configuration described in the present embodiment is naturally applicable to the insulator 10A described in the second embodiment. That is, as shown in FIG. 12, a configuration in which the insulator 10A shown in FIG. 9 protrudes from the lower surface of the counter electrode 10 on the fine particle generation cooling chamber 70 side may be adopted.

DESCRIPTION OF SYMBOLS 1 Transfer type electrode 2 Inner cylinder 3 Magnet 4 Outer cylinder 5, 6, 12, 13 Insulator 10 Counter electrode 10A Insulator 11 Wall part 15 Torch contact part 16 O-ring 20 Through part 25 Raw material passage part 26, 27 Gas passage part 35 Material vaporization reaction chamber 50 DC plasma torch 60 Vacuum pump 61 Plasma power supply 62 Cooling water supply part 63 First plasma gas supply part 64 Second plasma gas supply part 65 Plasma torch lifting mechanism 66 Powder material supply part 67 Gas supply unit 70 Particle generation cooling chamber 71 Particle capture chamber 72 Particle capture filter 73 Heat exchanger 100 Microorganism generator AX Central axis D1 Outer diameter D2 (of transfer type plasma electrode 1) D2 (of transfer type plasma electrode 1) Inner diameter D3 Ring-shaped outer diameter of counter electrode 10 D4 Ring-shaped inner diameter of counter electrode 10 P1 Transfer plasma

Claims (3)

DC plasma torch,
A counter electrode disposed oppositely from the DC plasma torch, and
The DC plasma torch is
A ring-shaped magnet;
A transitional plasma electrode having a cylindrical shape, wherein the magnet is disposed inside a cavity of the cylinder, and separated from the magnet by a predetermined distance;
Provided with a raw material material passage part through which the raw material material is provided, provided in a substantially central part of the DC plasma torch,
The counter electrode is
In a plan view from the DC plasma torch side, it has a ring shape,
A particulate generation cooling chamber that is in communication with the ring-shaped through-hole of the counter electrode and is cooled around the periphery;
The transitional plasma generated between the transitional plasma electrode and the counter electrode is rotated by the magnet,
The raw material material output from the raw material material passage portion is vaporized by the rotating transfer plasma, and is cooled in the fine particle generation cooling chamber through the penetration portion, thereby generating fine particles,
The side part facing the penetration part of the counter electrode is
An insulator,
The fine particle production | generation apparatus characterized by the above-mentioned. The insulator is
It is formed from the side surface portion of the counter electrode facing the penetrating portion to a part of the surface of the counter electrode facing the DC plasma torch.
The fine particle generating apparatus according to claim 1. The insulator is
Protrudes toward the particulate generation cooling chamber,
The fine particle generation device according to claim 1 or 2, wherein the fine particle generation device according to claim 1 or 2 is used.

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