JP7054663B2 - High frequency induced thermal plasma device - Google Patents

Description

The present invention relates to a high frequency induced thermal plasma apparatus.

The high-frequency induction heat plasma device is for plasma based on the principle of induction heating by supplying plasma gas into the insulating tube inside the plasma torch and supplying high-frequency power to the induction coil provided around the insulating tube. The gas is excited to generate thermal plasma.
It is known that this thermal plasma has an ultra-high temperature of several thousand degrees to 15,000 degrees in gas temperature, and when powder, liquid or gas is introduced into the center of the thermal plasma, it instantly occurs. Evaporates or melts. Then, by installing a water-cooled chamber in the lower stage of the plasma torch, the evaporated or melted powder, liquid or gas is rapidly cooled and solidified by supersaturation.

By using this high-frequency induced thermal plasma device, fine particles such as metals are evaporated in plasma to produce nanoparticles, and fine powder with complicated shapes is melted in plasma to form spheroids. It is possible to produce particles having a core-shell structure, decompose gas, and the like (see, for example, Patent Document 1).

Here, the conventional configuration of the high frequency induced thermal plasma apparatus will be described.
FIG. 6 shows an enlarged view of a plasma torch having a conventional configuration of a high-frequency induced thermal plasma apparatus.
The high-frequency induced thermal plasma apparatus 100 shown in FIG. 6 includes an RF (Radio Frequency) plasma torch 10 as a plasma torch that is a plasma generating unit.

The RF plasma torch 10 includes an insulating tube 12 and an induction coil 14. The induction coil 14 is provided around the insulating tube 12, and high-frequency power is supplied from a high-frequency oscillator (not shown). A plasma gas such as argon is supplied to the RF plasma torch 10 into the insulating tube 12 as shown by an arrow G in FIG. 6, and high-frequency power is supplied from the high-frequency oscillator to the induction coil 14. Thereby, the plasma gas can be excited by induction heating to generate the thermal plasma P in the insulating tube 12. It is known that this thermal plasma P has an ultra-high temperature of about several thousand degrees to 15,000 degrees at the temperature of the gas, and when powder, liquid, or gas is introduced into the center of the thermal plasma P, Instantly evaporates or melts.
The powder, liquid, or gas evaporated or melted by the thermal plasma P collides with the gas in, for example, a water-cooled chamber installed in the lower stage of the RF plasma torch 10, is rapidly cooled, and is solidified by supersaturation. As a result, a target sample such as nanoparticles, spherical particles, or particles having a core-shell structure can be obtained.

Here, a detailed enlarged view of the RF plasma torch 10 of FIG. 6 is shown in FIG.
As shown in FIG. 7, in the RF plasma torch 10, the inner tube 16 uses a ceramic material such as silicon nitride and the outer tube 17 is transparent so as not to block the strong magnetic field obtained by the high frequency current flowing through the induction coil 14. Insulating materials such as quartz tubes are used. Then, the cooling water W is circulated between the inner pipe 16 and the outer pipe 17 so as not to be damaged or melted by the radiant heat and the synchrotron radiation from the thermal plasma.
The inner pipe 16 and the outer pipe 17 are provided with O-rings 18 as sealing materials at the upper ends and the lower ends, respectively, to seal the cooling water W so as not to leak to the outside.

Japanese Unexamined Patent Publication No. 2001-217097

The method of supplying the plasma gas to the RF plasma torch 10 is as follows: a radial that supplies the plasma gas to the inner circumference of the insulating tube 12 along the axial direction as shown in FIG. 8 and a rotation of the inner circumference of the insulating tube 12 shown in FIG. There is a tangential to be supplied to do so.
In the case of Radial shown in FIG. 8, there is an advantage that the plasma frame is extended toward the outlet side of the plasma torch 10.
In the case of Tential shown in FIG. 9, there is an advantage that the residence time of the material put in the plasma is lengthened, and the diameter of the plasma can be increased.

However, in the case of Radial, the plasma frame tends to bend due to the influence of the gas flow and the magnetic field in the RF plasma torch 10. Then, the plasma frame bends near the outlet, and as shown in FIG. 10, which is an enlarged view near the lower end of the inner tube 16, the ultra-high temperature thermal plasma RP (Radial Plasma) approaches the inner tube 16. As a result, as shown in FIG. 10, a strong heat load is applied from the thermal plasma RP to the O-ring 18S that seals the cooling water under the inner pipe 16.
Further, in the case of Tangential, since the diameter of the plasma becomes large, as shown in FIG. 10, the ultra-high temperature thermal plasma TP (Tangential Plasma) approaches the inner tube 16. Also in this case, as shown in FIG. 10, a strong heat load is applied from the thermal plasma TP to the O-ring 18S that seals the cooling water under the inner pipe.

Further, by adding hydrogen to argon as a plasma gas, the heat conduction of the thermal plasma P (RP, TP) is increased, and the heat load on the O-ring 18S is increased.
Further, even when the high frequency output exceeds 30 kW, the heat load on the O-ring 18S becomes strong.

As shown in FIG. 10, since the O-ring 18S is not directly cooled by the cooling water W, when the heat load on the O-ring 18S becomes strong as described above, the heat resistance limit of the O-ring 18S is exceeded and the O-ring is O. The ring 18S may be melted. If the O-ring 18S is melted, the cooling water W may leak.

Further, the flow direction of the cooling water in the water-cooled double pipe of the plasma torch 10 is usually supplied from the bottom and discharged from the top.
A cross-sectional view of the inlet portion of the cooling water W in FIG. 7 is shown in FIG.
As shown in FIGS. 7 and 11, the cooling water W is passed through the inflow port provided in the lower flange.

However, the flow rate of the cooling water W changes due to the pressure difference in the water channel.
Here, in the configuration of FIG. 11, the amount of water is compared by the thickness of the arrow and is shown in FIG. As shown in FIG. 12, the amount of water is the largest in the vicinity of the inflow port, and the amount of water is the lowest in the location farthest from the inflow port at an angle of about 90 degrees from the inflow port. If the amount of water is low in some places like this, the cooling capacity of the inner pipe 16 is hindered, and the heat load on the O-ring 18 becomes strong in the places.

In order to solve the above-mentioned problems, in the present invention, the inner tube of the plasma generating portion can be sufficiently cooled, and the heat load on the encapsulant is reduced to reduce the cooling water due to the melting of the encapsulant. It is an object of the present invention to provide a high frequency induced thermal plasma apparatus capable of preventing leakage of water.

The present invention is a high-frequency induced thermal plasma apparatus provided with a plasma generating unit that generates thermal plasma by high-frequency induction and a chamber through which a gas generated by the thermal plasma is passed and cooled.
In the high frequency induced thermal plasma apparatus of the present invention, the plasma generating unit has a double tube structure consisting of an inner tube and an outer tube provided with an internal space for flowing cooling water, and an inner one for sealing the cooling water. It is provided with a sealing material provided so as to be in contact with the pipe. Further, a reinforcing portion having a wall thickness thicker than that of the other portion of the inner pipe is provided at a portion of the lower end of the inner pipe in contact with the sealing material. Furthermore, a water flow rotation mechanism is provided on the outside of a part of the inner pipe to rotate the water flow of the cooling water in a direction along the outer periphery of the inner pipe. Each of the water flow rotation mechanisms is provided between the outer water channels and between the cooling water outlet and the outer water channel of the inner pipe, and each water flow rotation mechanism has a flow path for passing the cooling water, and each water flow rotation. The direction of the flow path of the mechanism is the same diagonal direction with respect to the radial direction of the inner pipe.

According to the above-mentioned invention, since the inner pipe is uniformly cooled and the heat load applied to the encapsulant is reduced, it is possible to prevent problems such as leakage of cooling water due to melting damage of the encapsulant.

It is a schematic block diagram of the high frequency induction thermal plasma apparatus of embodiment of this invention. It is a detailed enlarged view of the RF plasma torch of FIG. It is an enlarged view near the lower end portion of the inner pipe of FIG. A and B are horizontal cross-sectional views near the water flow rotation mechanism of FIG. It is a figure which shows the example of the structure of the water flow rotation mechanism A to C. It is an enlarged view of the plasma torch of the conventional structure of a high frequency induction thermal plasma apparatus. It is a detailed enlarged view of the RF plasma torch of FIG. It is a figure which shows the case of Radial. It is a figure which shows the case of Tangential. It is an enlarged view near the lower end portion of the inner pipe of FIG. It is sectional drawing of the part of the inlet of the cooling water W of FIG. In the configuration of FIG. 11, it is a figure which compared the amount of water with the thickness of an arrow.

Hereinafter, the high frequency induced thermal plasma apparatus according to the present invention will be described in the following order with reference to the drawings.
1. 1. Outline of the present invention 2. Embodiment 3. Modification example

<1. Outline of the present invention>
The high-frequency induced thermal plasma apparatus of the present invention includes a plasma generating unit that generates thermal plasma by high-frequency induction, and a chamber that allows gas generated by the thermal plasma to pass through and cools the device.
In the high frequency induced thermal plasma apparatus of the present invention, the plasma generating unit has a double tube structure consisting of an inner tube and an outer tube provided with an internal space for flowing cooling water, and an inner one for sealing the cooling water. It is provided with a sealing material provided so as to be in contact with the pipe.
Further, a reinforcing portion having a wall thickness thicker than that of the other portion of the inner pipe is provided at a portion of the lower end of the inner pipe in contact with the sealing material.
Furthermore, a water flow rotation mechanism for rotating the water flow of the cooling water in the direction along the outer periphery of the inner pipe is provided on the outside of a part of the inner pipe.

The plasma generation unit of the high-frequency induced thermal plasma apparatus of the present invention can be configured by a plasma torch (for example, an RF plasma torch) or the like.
In the high-frequency induced thermal plasma apparatus of the present invention, the cooling water is flowed between the inner tube and the outer tube of the insulating tube, but the device is preferably configured so that the cooling water flows from the lower side to the upper side of the inner tube. do.

The present invention generates various types of thermal plasma (including high-frequency type or composites and hybrids thereof) that require plasma gas of several liters / minute to several thousand liters / minute under atmospheric pressure or 1 kPa or more. It can be applied to high frequency induced thermal plasma equipment.

(Reinforcing part at the lower end of the inner pipe)
As described above, in the high-frequency induced thermal plasma apparatus of the present invention, the portion of the insulating tube of the plasma generating portion (plasma torch, etc.) in contact with the sealing material at the lower end of the inner tube is thicker than the other parts of the inner tube. It has a thick reinforcing part. As a result, the sealing material in contact with the lower end of the inner pipe is arranged on the outside of the thick reinforcing portion.

By making the lower end of the inner tube of the insulating tube of the plasma generation part a reinforcing part thicker than the other parts, the lower end of the inner tube has a trumpet structure.
As the sealing material for sealing the cooling water, for example, an O-ring or a sealing material having another configuration can be used.
Since the encapsulant is in contact with the thick reinforcing portion, the distance from the thermal plasma to the encapsulant can be increased, so that the heat load applied to the encapsulant can be reduced and the encapsulant can be used. It can be prevented from reaching the melting point.
In particular, regardless of whether the plasma gas is supplied by either Radial or Tangential, the thermal plasma spreads outward at the lower end of the inner pipe and approaches the inner pipe. Therefore, a reinforcing portion is provided at the lower end of the inner pipe. This has the effect of reducing the heat load on the encapsulant.

The outer diameter of the reinforcing portion of the inner pipe is preferably increased by 6 to 40 mm with respect to the outer diameter of the other portion of the inner pipe.
If the difference between the outer diameter of the reinforcing portion and the outer diameter of the other portion is less than 6 mm, the effect of suppressing the heat load on the encapsulant and preventing the encapsulant from melting is diminished.
On the contrary, if the difference between the outer diameter of the reinforcing portion and the outer diameter of the other portion exceeds 40 mm, the inner pipe becomes expensive when the inner pipe is made of a material such as silicon nitride.

The inner tube is preferably made of silicon nitride.
Since the inner tube is made of silicon nitride and the silicon nitride is opaque, the light generated from the plasma is blocked and is not irradiated to the outside. As a result, it is possible to avoid burning of the structural parts of the device due to the light generated from the plasma. Therefore, it is possible to avoid burning of the sealing material such as the O-ring due to the light generated from the plasma.

(Water flow rotation mechanism)
In the high-frequency induced thermal plasma apparatus of the present invention, a water flow rotation mechanism for rotating the water flow of the cooling water on the outer periphery of the inner tube in the circumferential direction of the inner tube is provided on a part of the outer periphery of the inner tube.
By rotating the water flow of the cooling water on the outer circumference of the inner pipe in the circumferential direction by the water flow rotation mechanism, the unevenness of the amount of cooling water depending on the site, that is, the non-uniformity of the amount of water is eliminated, and the entire outer circumference of the inner pipe is completely eliminated. The circumference can be cooled uniformly.

The water flow rotation mechanism is provided on a part of the outer circumference of the inner pipe. That is, a water flow rotation mechanism is provided at any position from the upper end to the lower end of the outer circumference of the inner pipe.

More preferably, a water flow rotation mechanism is provided between the inlet of the cooling water and the water channel on the outer periphery of the inner pipe, and between the outlet of the cooling water and the water channel on the outer periphery of the inner pipe.
Thereby, each water flow rotation mechanism can more effectively rotate the cooling water along the outer circumference of the inner pipe.

As a specific configuration of the water flow rotation mechanism, for example, a ring-shaped (concentric circle) member having an inner diameter larger than the outer diameter of the inner pipe is formed so as to be directed diagonally with respect to the radial direction of the inner pipe. It is conceivable to provide a plurality of the formed flow paths and allow the cooling water to pass through the flow paths.
The flow path may be formed in a groove shape in the upper part or the lower part of the member, or may be formed in a through hole in the central portion of the member.
Since the flow path is provided in a direction oblique to the radial direction of the inner pipe, a rotary flow is generated in the cooling water that has passed through the flow path. Then, by this rotating flow, the unevenness (non-uniformity) of the amount of water depending on the portion is eliminated, and the entire circumference of the outer circumference of the inner pipe including the thick reinforcing portion can be uniformly cooled.

The reinforcing portion (trumpet structure) and the water flow rotation mechanism of the inner tube of the high-frequency induced thermal plasma apparatus of the present invention can be applied regardless of whether the above-mentioned plasma gas supply method is Radial or Tangential. ..
In particular, in the case of Tangential, since the thermal plasma easily spreads to the vicinity of the inner wall of the chamber, the effect of providing the reinforcing portion (trumpet structure) of the inner pipe and the water flow rotation mechanism is great.

A tapered portion having a tapered structure may be provided at the boundary between the reinforcing portion at the lower end of the inner pipe and the portion having a normal thickness so that the thickness gradually changes.
For example, when silicon nitride is used for the inner tube, a configuration having a tapered structure has an advantage that silicon nitride can be easily processed as compared with a configuration without a tapered structure.

The high frequency induced thermal plasma apparatus of the present invention can be applied to various high frequency induced thermal plasma apparatus.
As the high frequency inductively coupled thermal plasma device, for example, a type having one generation part of the high frequency inductively coupled thermal plasma, or a hybrid type in which a DC (Direct Current) jet is superimposed on the high frequency inductively coupled thermal plasma, two or three high frequencies. Examples include a tandem type in which inductively coupled plasmas are arranged in series.

<2. Embodiment>
FIG. 1 shows a schematic configuration diagram of the high-frequency induced thermal plasma apparatus according to the embodiment of the present invention.
In this embodiment, particles are generated by a high-frequency induced thermal plasma device, and the generated particles are recovered.

The high-frequency induced thermal plasma apparatus 1 of the present embodiment shown in FIG. 1 includes an RF plasma torch 10 as a plasma torch which is a plasma generating unit, and further comprises a chamber, a cooling unit 30, and a recovery unit 40. I have.

The RF plasma torch 10 includes an insulating tube 12, a high frequency oscillator 13, and an induction coil 14. The induction coil 14 is provided around the insulating tube 12, and high-frequency power is supplied from the high-frequency oscillator 13. A powder feeder 11 is connected to the RF plasma torch 10, and the raw material powder and a gas such as Ar (argon), which is a carrier gas, are transferred from the powder feeder 11 to the plasma center in the insulating tube 12 through the probe 15. Is supplied to.

The chamber includes an upper transparent quartz double-tube water-cooling chamber 21 and a lower stainless steel double-tube water-cooling chamber 22. Since the upper part of the chamber is a transparent quartz double tube water cooling chamber 21 which is transparent, the plasma state can be observed and monitored from the outside of the high frequency induced thermal plasma apparatus 1.

The cooling unit 30 is configured by using four cooling plates 31, 32, 31, 32 which are a set of cooling plates 31, 32 having through holes 33 formed at different positions. Each of the cooling plates 31 and 32 is made of a water-cooled metal having good heat conduction such as copper.

The collection unit 40 is provided with, for example, a cloth filter 41 in the pipe. A vacuum pump 51 is connected to the rear stage of the recovery unit 40, and the vacuum pump 51 can exhaust the gas after collecting the particles.

The high-frequency induced thermal plasma apparatus 1 of the present embodiment is particularly characterized by the configuration of the RF plasma torch 10.
A detailed enlarged view of the RF plasma torch 10 of the high frequency induced thermal plasma apparatus 1 of FIG. 1 is shown in FIG.

As shown in FIG. 2, in the RF plasma torch 10, the inner tube 16 uses a ceramic material such as silicon nitride and the outer tube 17 is transparent so as not to block the strong magnetic field obtained by the high frequency current flowing through the induction coil 14. Insulating materials such as quartz tubes are used. Then, the cooling water W is circulated between the inner pipe 16 and the outer pipe 17 so as not to be damaged or melted by the radiant heat and the synchrotron radiation from the thermal plasma.
Further, the inner pipe 16 and the outer pipe 17 are provided with O-rings 18 as sealing materials at the lower ends and the upper ends, respectively, to seal the cooling water so as not to leak to the outside.

Specifically, a lower flange composed of a first member 19A and a second member 20A is provided at the lower end portions of the inner pipe 16 and the outer pipe 17, and a first portion is provided at the upper end portions of the inner pipe 16 and the outer pipe 17. An upper flange composed of the member 19B of 1 and the member 20B of the second is provided.
The second member 20A of the lower flange is provided with an inlet for the cooling water W, and the second member 20B of the upper flange is provided with an outlet for the cooling water W. Then, the cooling water W flows between the inner pipe 16 and the outer pipe 17 from the lower side to the upper side.
Further, between the lower end of the inner pipe 16 and the second member 20A of the lower flange, between the upper end of the inner pipe 16 and the second member 20B of the upper flange, the lower end of the outer pipe 17 and the lower flange. An O-ring 18 is provided as a sealing material between the first member 19A, between the upper end portion of the outer pipe 17 and the first member 19B of the upper flange, respectively.

In the present embodiment, the RF plasma torch 10 further has a reinforcing portion 16A formed at the lower end portion of the inner pipe 16 to be thicker than the other portions of the inner pipe 16. Since the reinforcing portion 16A is provided at the lower end portion of the inner pipe 16, the lower end portion of the inner pipe 16 has a trumpet structure.
An O-ring 18 is provided on the outside of the reinforcing portion 16A of the inner pipe 16. Hereinafter, among the four O-rings 18, the O-ring 18 outside the reinforcing portion 16A of the inner pipe 16 is distinguished as the O-ring 18S.

Further, in the present embodiment, between the inlet of the cooling water W at the lower part of the RF plasma torch 10 and the water channel on the outer periphery of the inner pipe 16, and the outlet and the inner pipe 16 of the cooling water W at the upper part of the RF plasma torch. Water flow rotation mechanisms 61A and 61B are provided between the water channels on the outer periphery of the torch, respectively. These water flow rotation mechanisms 61A and 61B have a flow path 62 in the central portion through which the cooling water W passes.

Here, an enlarged view of the vicinity of the lower end portion of the inner pipe 16 of FIG. 2 is shown in FIG.
As shown in FIG. 3, since the reinforcing portion 16A is provided at the lower end of the inner pipe 16 and the O-ring 18S is provided on the outside of the reinforcing portion 16A, the thermal plasma P to the O-ring 18S are provided by the reinforcing portion 16A. The distance becomes far. Further, as shown by the arrow in FIG. 3, the reinforcing portion 16A is cooled by the cooling water W.
By these actions, the heat load received by the O-ring 18S can be significantly reduced, so that it is possible to prevent the O-ring 18S from being melted by the heat load and the cooling water W from leaking.
Therefore, for example, as in the case where the thermal plasma P is a hydrogen thermal plasma, even if the thermal plasma has better thermal conductivity, there is a distance from the thermal plasma P to the O-ring 18S due to the reinforcing portion 16A. By cooling the inner pipe 16 with water, it is possible to prevent the O-ring 18S from being melted.

Further, horizontal cross-sectional views of the vicinity of the water flow rotation mechanisms 61A and 61B of FIG. 2 are shown in FIGS. 4A and 4B. FIG. 4A shows a horizontal cross-sectional view of the vicinity of the water flow rotation mechanism 61A at the lower end of the inner pipe 16, and FIG. 4B shows a horizontal cross-sectional view of the vicinity of the water flow rotation mechanism 61B at the upper end of the inner pipe 16.
As shown in FIGS. 4A and 4B, each of the water flow rotation mechanisms 61A and 61B has several flow paths 62 through holes in the direction diagonally to the right with respect to the radial direction of the concentric water flow rotation mechanisms 61A and 61B. It is provided. As a result, the cooling water W in front of and behind the flow path 62 can be imparted with a clockwise rotational flow by the action of the cooling water W passing through the flow path 62 in the diagonally right direction.
The cooling water W flowing in from the lower end of the inner pipe 16 is provided with a clockwise rotating flow by the flow path 62 of the water flow rotating mechanism 61A at the lower end shown in FIG. 4A. Then, it rises along the outer wall of the inner pipe 16 while remaining in a clockwise rotation flow, passes through the water flow rotation mechanism 61B at the upper end portion shown in FIG. 4B, and heads toward the outflow port.
That is, the cooling water W becomes a clockwise rotating flow not only in the vicinity of the respective water flow rotation mechanisms 61A and 61B but also in the middle section along the outer circumference of the inner pipe 16, and spirally and evenly covers the entire outer circumference of the inner pipe 16. Cooling water W flows. This makes it possible to cool the periphery of the inner tube 16 almost uniformly without spots.
In this way, it is possible to prevent the O-ring 18S in contact with the lower end portion of the inner pipe 16 from being melted and damaged due to the heating of the inner pipe 16 of the insulating pipe 12, so that water leakage can be eliminated.

In the configuration shown in FIGS. 4A and 4B, the cooling water W before and after the flow path 62 is set so that the flow paths 62 of the water flow rotation mechanisms 61A and 61B are diagonally to the right with respect to the radial direction of the water flow rotation mechanisms 61A and 61B. Was given a clockwise rotating flow.
Contrary to the configurations shown in FIGS. 4A and 4B, the flow path of the water flow rotation mechanism is set diagonally to the left with respect to the radial direction of the water flow rotation mechanism, and is counterclockwise to the cooling water before and after the flow path. It may be configured to give a rotating flow.

Further, examples of the configuration of the water flow rotation mechanism 61 (61A, 61B) are shown in FIGS. 5A to 5C, respectively.
FIG. 5A shows a configuration in which the flow path 62 is formed in a groove shape on the upper side of the water flow rotation mechanism 61 (61A, 61B).
FIG. 5B has a configuration in which a flow path 62 is formed by a through hole in the central portion of the water flow rotation mechanism 61 (61A, 61B), similarly to the water flow rotation mechanisms 61A and 61B shown in the cross-sectional view of FIG.
FIG. 5C shows a configuration in which the flow path 62 is formed in a groove shape on the lower side of the water flow rotation mechanism 61 (61A, 61B).
A rotating flow can be applied to the cooling water W in any of the shapes of FIGS. 5A to 5C.
In each configuration shown in FIGS. 5A to 5C, the cross-sectional shape of the flow path 62 is substantially rectangular, but the cross-sectional shape of the flow path is another cross-sectional shape, for example, a U-shape, a semicircular shape, a circular shape, an elliptical shape, or the like. It is also possible. Even if the flow path has these cross-sectional shapes, a rotating flow can be applied to the cooling water as in the case where the cross-sectional shape is rectangular.

(Operation of high frequency induced thermal plasma device)
Subsequently, the operation of producing particles such as nanoparticles in the high-frequency induced thermal plasma apparatus 1 of the present embodiment will be described.
First, the vacuum pump 51 is used to evacuate the inside of each part 10, 21, 22, 30, 40 of the high frequency induced thermal plasma apparatus 1.
Next, a plasma gas (argon or the like) is supplied from the upper part of the RF plasma torch 10, and high-frequency power is supplied from the high-frequency oscillator 13 to the induction coil 14 to generate thermal plasma. At this time, for example, the inside of each part 10, 21, 22, 30, 40 is made to have a high vacuum until the operating pressure becomes 1 kPa or less.

Then, when the raw material powder (metal powder or the like) is housed in the powder feeder 11, the carrier gas (argon or the like) is supplied, and the raw material powder is quantitatively supplied together with the carrier gas to the center of the thermal plasma. The raw material powder melts or evaporates due to the plasma.

The melted or evaporated raw material powder is rapidly cooled by gas molecules in the transparent quartz double tube water cooling chamber 21 to generate particles.
Further, the gas and the generated particles are cooled by the stainless double tube water cooling chamber 22.
Then, the generated particles are further sufficiently cooled by passing through the through holes 33 of the cooling plates 31 and 32 of the cooling unit 30, and then collected by the filter 41 of the collection unit 40.

<3. Modification example>
Hereinafter, a modified example of the configuration of the above-described embodiment will be described.

(Application to various high-frequency induced thermal plasma devices)
In the above-described embodiment, the high-frequency induced thermal plasma apparatus 1 is configured to have only one plasma generating unit (RF plasma torch 10) that generates high-frequency induced thermal plasma.
The present invention is not limited to the high frequency induced thermal plasma apparatus having only one plasma generating portion for generating the high frequency induced thermal plasma, and can be applied to the high frequency induced thermal plasma apparatus having other configurations. For example, it is also applied to the above-mentioned hybrid type high frequency inductively coupled plasma device in which a DC jet is superposed on the high frequency inductively coupled plasma and a tandem type high frequency inductively coupled plasma in which two or three high frequency inductively coupled plasmas are arranged in series. be able to.

In the above-described embodiment, the high-frequency induced thermal plasma apparatus 1 is applied to a configuration in which particles are generated by the high-frequency induced thermal plasma apparatus 1 and the generated particles are recovered.
The present invention is not limited to a configuration in which particles are generated by a high-frequency induced thermal plasma apparatus and the generated particles are recovered, and the present invention can be applied to a high-frequency induced thermal plasma apparatus having other configurations. For example, it is also applied to a high-frequency induced thermal plasma device having a structure in which a gas of an organic halogen compound such as chlorofluorocarbon or halon is supplied to a plasma generating part to decompose the supplied gas, or a structure in which a film is formed on a substrate. be able to.

1 High frequency induction thermal plasma device, 10 RF plasma torch, 11 powder feeder, 12 insulation tube, 13 high frequency oscillator, 14 induction coil, 15 probe, 16 inner tube, 16A reinforcement, 17 outer tube, 18,18SO ring , 19A 1st member of lower flange, 19B 1st member of upper flange, 20A 2nd member of lower flange, 20B 2nd member of lower flange, 21 transparent quartz double tube water cooling chamber, 22 Stainless steel double tube water cooling chamber, 30 cooling part, 31, 32 cooling plate, 33 through hole, 40 recovery part, 41 filter, 51 vacuum pump, 61, 61A, 61B water flow rotation mechanism, 62 flow path, P, RP ， TP thermal plasma ， W cooling water

Claims (2)

A high-frequency induced thermal plasma apparatus provided with a plasma generating unit that generates thermal plasma by high-frequency induction and a chamber that allows gas generated by the thermal plasma to pass through and cools the plasma.
The plasma generating portion has a double pipe structure consisting of an inner pipe and an outer pipe having an internal space for flowing cooling water, and a sealing provided so as to be in contact with the inner pipe for sealing the cooling water. With wood,
A reinforcing portion having a wall thickness thicker than that of the other portion of the inner pipe is provided at a portion of the lower end of the inner pipe in contact with the sealing material.
A water flow rotation mechanism for rotating the water flow of the cooling water in a direction along the outer circumference of the inner pipe is provided on the outside of a part of the inner pipe.
The water flow rotation mechanism is provided between the inlet of the cooling water and the water channel on the outer periphery of the inner pipe, and between the outlet of the cooling water and the water channel on the outer periphery of the inner pipe.
Each of the water flow rotation mechanisms has a flow path through which the cooling water passes, and the direction of the flow path of each of the water flow rotation mechanisms is the same oblique direction with respect to the radial direction of the inner pipe.
High frequency induced thermal plasma device. A lower flange is connected to the lower end of the inner pipe and the lower end of the outer pipe.
An upper flange is connected to the upper end of the inner pipe and the upper end of the outer pipe.
The lower flange has a first member connected to the lower end of the inner pipe and a second member connected to the lower end of the outer pipe, and the first member of the lower flange. The cooling water inlet is formed between the member and the second member of the lower flange.
The upper flange has a first member connected to the upper end portion of the inner pipe and a second member connected to the upper end portion of the outer pipe, and has the first member of the upper flange. The cooling water outlet is formed between the upper flange and the second member.
The water flow rotation mechanism is provided at the inlet of the cooling water, which is composed of a member different from the first member of the lower flange and the second member of the lower flange.
The water flow rotation mechanism is provided at the outlet of the cooling water, which is composed of a member different from the first member of the upper flange and the second member of the upper flange.
The high frequency induced thermal plasma apparatus according to claim 1.

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