JP4531451B2 - Plasma generation apparatus in atmospheric pressure and plasma generation support apparatus in atmospheric pressure - Google Patents

Description

  The present invention relates to a method for generating plasma in atmospheric pressure and an apparatus for generating plasma in atmospheric pressure.

Conventionally, plasma ignition and maintenance are generally performed in a low pressure state. This is because the ambient low-temperature neutral gas density (ordinary gas density that is not plasma) is very large at atmospheric pressure, and it is very difficult to ignite and maintain the high-temperature plasma.
As a conventional technique, the pressure is reduced at the start of plasma discharge, plasma is generated using microwaves in a reduced pressure state, the pressure is returned to atmospheric pressure while maintaining the generated plasma, and the plasma is heated at high temperature in atmospheric pressure. A plasma processing apparatus for heat-treating the substrate surface has been proposed (see, for example, Patent Document 1).
Further, as shown in FIG. 8, in the atmospheric pressure, the microwave is applied to the rod-shaped antenna 30A provided in the cavity 20A that can be matched by the matching unit, and the inside of the cavity 20A in which the tip of the antenna 30A is accommodated. A plasma generation apparatus for generating plasma has also been proposed.
JP 2004-031509 A

The prior art described in Patent Document 1 improves the ignitability of plasma and stabilizes the generation of plasma when generating plasma using microwaves. However, when generating plasma stably, It is necessary to reduce the pressure (reduced pressure to about 100 Torr). In order to reduce the pressure, equipment for reducing pressure such as an exhaust pump and a valve and the time required for pressure reduction are required, and it takes much time to generate plasma.
In the prior art shown in FIG. 8, the microwave is resonated (resonated) in the cavity 20A (resonance box) to amplify the microwave. However, because the resonance point slightly changes due to the generated plasma, There is always a need to be consistent. That is, in order to maintain the generated plasma, it is necessary to constantly adjust the cavity matching unit 20B, which is very laborious. The cavity 20A has a relatively small size (about 10 [cm] square) in order to obtain a larger resonance (resonance), and has a relatively large volume of plasma having a diameter of several tens [cm] or more. Cannot be generated. Further, if the generated plasma covers the tip of the antenna 30A, the electric field of the antenna 30A is cut off and it becomes very difficult to maintain the plasma. Therefore, a gas (for example, nitrogen, helium, etc.) is flowed to cause the plasma to flow. The position is forcibly moved from the tip of the antenna 30A.
The present invention was devised in view of such points, and does not require a decompression facility or the like, and can ignite and maintain plasma relatively easily at atmospheric pressure. It is an object of the present invention to provide a plasma generation method and apparatus therefor.

  As a means for solving the above problem, in the plasma generation method described in the present embodiment, the inside of the processing space surrounded by the conductor and at the atmospheric pressure is the predetermined length in the processing space. Then, an antenna member having conductivity is arranged so that one end in the processing space is grounded to the conductor, and plasma is generated by irradiating microwaves in the processing space.

  In addition, the atmospheric pressure plasma generation apparatus described in this embodiment is surrounded by a conductor and has an atmospheric pressure processing space, an antenna member, and a microwave generation unit. The microwave generating means irradiates the processing space with microwaves, the antenna member has conductivity and has a substantially columnar shape, and one end in the processing space is connected to the conductor. It is provided so as to be grounded and to have a predetermined length in the processing space.

  Further, in the plasma generation apparatus in the atmospheric pressure described in the present embodiment, the antenna member has a length equal to or longer than a predetermined length, and is arbitrarily selected from a portion grounded with a conductor constituting the processing space. Length detection means capable of inserting a length into the processing space, and capable of detecting the length of the antenna member in the processing space, and an antenna member inserted into the processing space based on a detection amount by the detection means And a length adjusting means capable of adjusting the length to a predetermined length.

  In addition, the atmospheric pressure plasma generation apparatus described in this embodiment includes a holding container that holds generated plasma. The upper part of the holding container has a substantially spherical or substantially hemispherical shape, and a hole of a predetermined size is provided in the upper part of the holding container. It is arranged so as to cover.

Further, the plasma generation apparatus in the atmospheric pressure described in this embodiment includes a microwave generation unit, a processing space surrounded by a conductor and having an atmospheric pressure inside, and a microwave output from the microwave generation unit. A circulator for guiding the reflected wave of the microwave to the processing space, a directional coupler capable of measuring the incident wave of the microwave to the processing space and the reflected wave of the microwave from the processing space, and the reflected wave A matching unit that can be adjusted in amount, a holding container that is disposed in the processing space and that holds the generated plasma, and is disposed in the holding container and has conductivity and a substantially columnar shape, And an antenna member capable of inserting an arbitrary length into the processing space from the grounded portion.
The length detecting means capable of detecting the length of the antenna member in the processing space, and the length of the antenna member inserted into the processing space can be adjusted to a predetermined length based on the amount detected by the length detecting means. Length adjusting means, temperature detecting means capable of detecting the temperature of the generated plasma, and output control means for controlling the output of the microwave based on the detection amount by the temperature detecting means.

  In addition, the atmospheric pressure plasma generator described in this embodiment includes a processing space surrounded by a conductor and an atmospheric pressure inside, and one or a plurality of microwaves provided on an arbitrary surface of the processing space. A generating means, a reflector provided in proximity to the microwave generating means and diffusing the microwaves output from the microwave generating means, a holding container disposed in the processing space and holding the generated plasma, An antenna member that is disposed in the holding container, has conductivity and has a substantially columnar shape, and can be inserted into the processing space at any length from a grounded portion with the conductor constituting the processing space, and the processing space A length detecting means capable of detecting the length of the antenna member in the inside, and a length capable of adjusting the length of the antenna member inserted into the processing space to a predetermined length based on a detection amount by the length detecting means Comprising a regulating means, a detectable temperature detecting means the temperature of the generated plasma, and output control means for controlling the output of the microwave based on the detected amount by the temperature detection means.

  Further, in the plasma generation apparatus in the atmospheric pressure described in the present embodiment, the holding container is configured by stacking two containers, an inner holding container having a relatively small diameter and an outer holding container having a relatively large diameter. The cooling fluid is flowing in the space between the inner holding container and the outer holding container.

The first aspect of the present invention is a plasma generation apparatus in atmospheric pressure as described in claim 1.
The plasma generation apparatus under atmospheric pressure according to claim 1 is a first chamber that is surrounded by a conductor and has a processing space having an atmospheric pressure inside, a microwave generation means, a conductivity and a substantially columnar shape. A first antenna member having a predetermined length, a second antenna member having a second column length having conductivity and a substantially columnar shape, a base portion made of a heat-resistant dielectric, and generated plasma And a holding vessel for holding the plasma generating apparatus in an atmospheric pressure.
The microwave generation means irradiates the processing space with microwaves, and the first antenna member is long in the processing space so that one end in the processing space is grounded to the conductor. The holding container has a substantially spherical or substantially hemispherical shape at the top, and a hole of a predetermined size is provided at the top, so that the processing space is provided. It arrange | positions so that the said 1st antenna member may be covered inside.
The base portion is disposed in the holding container, and the second antenna member is disposed substantially horizontally on the base portion .

The second invention of the present invention is the plasma generation support device in the atmospheric pressure as described in claim 2 .
The apparatus for supporting plasma generation in atmospheric pressure according to claim 2, wherein the apparatus is surrounded by a conductor and disposed inside a processing space having an atmospheric pressure, and generates plasma by irradiating microwaves. A plasma generation support device having a substantially spherical or hemispherical upper portion, and a hole of a predetermined size provided in the upper portion to hold the generated plasma, and a conductive A flat bottom member, a first antenna member having conductivity and a substantially columnar shape, and a second predetermined length having conductivity and a substantially columnar shape. The second antenna member and a base portion made of a heat-resistant dielectric are provided.
The bottom member is arranged in the holding container, and one end of the first antenna member is fixed to the bottom member and arranged in the holding container.
The base portion is disposed in the holding container, and the second antenna member is disposed substantially horizontally on the base portion .

  If the method for generating plasma at atmospheric pressure described in this embodiment is used, it is possible to ignite and maintain plasma relatively easily at atmospheric pressure using microwaves without the need for equipment for decompression. Is possible.

  In addition, according to the plasma generation apparatus in the atmospheric pressure described in the present embodiment, it is possible to ignite and maintain plasma relatively easily in the atmospheric pressure using a microwave without using a decompression facility or the like. It is possible.

  Further, according to the plasma generation apparatus in the atmospheric pressure described in the present embodiment, when the length of the antenna member fluctuates (when the length is shortened by melting, evaporation, etc. by absorbing and discharging microwaves) Etc.), it is possible to maintain the length of the antenna member at an appropriate length that most easily absorbs microwaves.

  Further, according to the plasma generation apparatus in the atmospheric pressure described in the present embodiment, it is convenient because the plasma drifting in the processing space can be maintained in the holding container. Also, the hole of a predetermined size provided in the upper part can prevent the generated high-temperature plasma from automatically moving to the upper part by buoyancy in the holding container and covering the antenna member (antenna member Is covered with plasma, it becomes difficult to maintain the generated plasma).

  In addition, according to the plasma generation apparatus in the atmospheric pressure described in the present embodiment, it is possible to stably irradiate a microwave having a relatively large output continuously for several hours to several days, and industrially. Therefore, it is possible to realize a plasma generation apparatus in an atmospheric pressure capable of continuously generating and maintaining plasma for several hours to several days in various applications.

  In addition, according to the plasma generation apparatus in the atmospheric pressure described in the present embodiment, a relatively large output micrometer with a simpler configuration than the plasma generation apparatus in the atmospheric pressure described in claim 5. It is possible to realize a plasma generation apparatus in an atmospheric pressure capable of generating and maintaining plasma by stably irradiating waves.

  Moreover, according to the plasma generation apparatus in the atmospheric pressure described in the present embodiment, the durability of the holding container can be further improved by cooling the holding container with a double structure.

  In addition, according to the plasma generation apparatus in the atmospheric pressure according to claim 1, the second antenna member disposed substantially horizontally on the (heat-resistant) dielectric is used for plasma ignition and grounded. The antenna member can be used for maintaining plasma, and the ignitability can be further improved.

Moreover, if the plasma generation support apparatus in the atmospheric pressure according to claim 2 is used , for example, by putting the plasma generation support apparatus in the atmospheric pressure into a home microwave oven or the like and irradiating microwaves, Plasma can be generated easily and can be easily applied to experimental teaching materials, toys, and the like.

The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an embodiment (first embodiment) of a plasma generation apparatus under atmospheric pressure according to the present invention.
◆ [First embodiment (FIGS. 1 to 3)]
In the first embodiment, a microwave having a relatively large output, for example, exceeding 5 kW, can be continuously generated for several hours to several days to generate and maintain a relatively large volume of plasma. 2 shows an example of a plasma generating apparatus in FIG.
● [Overall configuration of plasma generator (Fig. 1)]
The plasma generation apparatus in the atmospheric pressure in the present embodiment includes a microwave generation means 10, a circulator 11, a directional coupler 12, a matching unit 13, a horn 14, and a housing 20. Is included. Moreover, the housing | casing 20 is comprised in the substantially box shape with the conductor, the inside of the housing | casing 20 is enclosed with the conductor, and the processing space 20a of atmospheric pressure is formed.
A holding container 40 is disposed in the processing space 20 a, and an antenna member 30 is erected in the holding container 40. In addition, it is preferable that the upper part of the holding container 40 (formed of a heat-resistant material that allows microwaves such as glass and ceramic) to have a spherical or hemispherical shape. This is because the spherical or hemispherical shape does not cause a concentration of thermal stress at a specific site and has high durability.

The microwave generation means 10 outputs an output microwave based on the control signal from the output control means 10a. The output control means 10a is based on the detected amount from the temperature detection means 10b (the temperature is estimated by a non-contact temperature detection means such as an optical spectrum), and the temperature at a predetermined position (center portion etc.) of the generated plasma 50. The output of the microwave generation means 10 is controlled so that becomes a target temperature (for example, about 6000 [° C.]).
The circulator 11 is disposed in a (rectangular) waveguide that guides the microwave output from the microwave generation means 10 to the processing space 20a, and the microwave reflected from the processing space or the like does not return to the microwave generation means 10. To escape. Further, the dummy load 11a attached to the tip consumes the reflected power. Thereby, even if the microwave generating means 10 is operated continuously for several hours to several days, the microwave generating means 10 does not receive the microwave output by itself (the reflected microwave is applied to the dummy load 11a). Absorbed) and stable operation (safe operation).

The coupler 12 (such as a directional coupler) outputs the amount of microwaves that are output from the microwave generation means 10 and travel toward the processing space 20a, and the reflected waves that are reflected from the processing space 20a and return to the microwave generation means 10. The amount can be measured. Then, the matching unit 13 (stub tuner or the like) is adjusted so that the amount of the reflected wave is minimized (substantially zero).
Resonance can be suppressed by making the processing space 20a sufficiently larger than the wavelength λ of the microwave. Further, in the present embodiment, since the processing space 20a is sufficiently larger than the wavelength λ, the Q value for the microwave in the processing space 20a is low, and it is not necessary to always keep matching according to the plasma generation state. Once matching is achieved, there is little need to adjust the matcher 13 thereafter.

Then, when the microwave is incident on the processing space 20a, the processing space 20a is irradiated from the horn 14 whose opening is set to a predetermined opening angle. The predetermined opening angle of the horn 14 is set to an angle at which the irradiated microwave can wrap the holding container 40. The horn 14 may be omitted.
The holding container 40 is disposed in the processing space 20a and has, for example, a substantially cylindrical shape, and an upper portion has a substantially spherical or substantially hemispherical shape, and is heat resistant to pass microwaves such as glass and ceramic. It is made of material. In addition, a hole 41 of a predetermined size is provided in the upper part of the holding container 40.
The antenna member 30 is arranged in the holding container 40 at a predetermined angle (for example, 45 [°] to 90 [°]). Since the antenna member 30 may be melted and drooped, it is preferable to set the antenna member 30 to be substantially vertical (90 [°]). In the present embodiment, the processing space 20a is disposed substantially vertically from the bottom surface. The antenna member 30 is conductive and has a substantially columnar shape, and one end (lower end) in the processing space is grounded (contacted) with the conductive surface forming the processing space 20a. ing. Further, the other end of the antenna member 30 is located in the processing space 20a without being grounded.
The length detecting means 32 and 33 capable of detecting the length of the antenna member 30 and the length adjusting means 31 and 34 capable of adjusting the length of the antenna member 30 inserted into the processing space 20a to a predetermined length. The description will be described later.

● [Structure of antenna member and appearance of plasma generation (Figure 2)]
Next, the structure of the antenna member 30 is demonstrated using FIG. 2 (A) and (B).
The antenna member 30 is arranged substantially vertically from a conductive plate (in this case, any surface such as the bottom surface or side surface of the housing 20) in order to concentrate the microwave electric field (for example, vertical when standing on the bottom surface). In the case of standing on the side, it is preferably arranged horizontally (perpendicular to the side). Further, as shown in FIG. 2B, the bottom member 35 (conductive plate) may be erected vertically. Note that, regardless of whether the antenna member 30 stands on an arbitrary surface of the housing 20 or a conductive plate, one end of the antenna member 30 is grounded (contacted) with the conductive member.
When the wavelength of the microwave is λ, the length Lver of the antenna member 30 (the length in the processing space 20a) is ¼ of λ in the case of a one-side grounded antenna (in this embodiment). Setting the length is preferable because the electric field of the microwave becomes maximum at the end opposite to the end on the ground side of the antenna. For example, when a microwave having a frequency of 2.45 [GHz] is used, the wavelength λ is 12.2 [cm], and thus the length of the antenna member 30 is set to 12.2 / 4 = 3.05 [cm]. (Approximately 3 [cm]).

Next, how the plasma is generated will be described with reference to FIGS.
When a microwave is output from the microwave generation means 10 in the plasma generation apparatus in the atmospheric pressure shown in FIG. 1, the antenna member 30 concentrates the electric field of the microwave, so that the end 30T (grounded on the conductive member) The electric field concentrates on the tip of the non-contact side (FIG. 2C), and the gas in the atmosphere is ionized by this electric field, and the plasma 50 is ignited (FIG. 2D). When ionization further progresses and the volume of the plasma 50 increases, the plasma 50 eventually moves above the holding container 40 by buoyancy (FIG. 2E). If the output of the microwave is continued in this state, the temperature and density of the plasma 50 increase at the destination, and the microwave is well absorbed and maintained.

In order to concentrate the electric field more, the antenna member 30 has conductivity and preferably has a thinner shape (the diameter φA (refer to FIGS. 2A and 2B) is preferably smaller), but is too thin. And the progress of melting or evaporation is not preferable. For this reason, in this embodiment, the antenna member 30 having a diameter φA of 1 [mm] or less (preferably about 0.3 [mm] to 1.0 [mm]) is used. In order to suppress melting or evaporation, a material having a high melting point is preferable, and tungsten, molybdenum, and a carbon rod (such as a mechanical pencil core) are preferable. Of course, you may use metals, such as iron and aluminum. The shape of the antenna member 30 may be a cylinder or a polygonal column.
The amount (size) of the plasma 50 is substantially determined by the capacity of the holding container 40, and the height of the moving destination of the plasma 50 is substantially determined by the height of the holding container 50. Further, the temperature of the plasma 50 can be controlled by the microwave output from the microwave generating means 10.
Further, as described above, it is most preferable to set the length of the antenna member 30 to ¼ of the wavelength λ of the microwave. However, when the plasma 50 is ignited and maintained, the antenna The tip of the member 30 melts or evaporates and becomes shorter than ¼ of λ. If the length of the antenna member 30 deviates from an allowable error range in the vicinity of ¼ of λ, the electric field strength concentrated on the tip portion is greatly reduced, and it becomes difficult to ignite and maintain the plasma 50.

  Therefore, as shown in FIG. 1, in order to always maintain the length Lver (the length located in the processing space 20a) of the antenna member 30 at ¼ of λ, the antenna member 30 in the processing space 20a has a length Lver. Length detection means 32 and 33 capable of detecting the length Lver, and length adjustment means capable of adjusting the length of the antenna member 30 inserted into the processing space 20a based on the detection amount of the length detection means 32 and 33 31 and 34. For example, the length detection means 32 and 33 are non-contact photoelectric sensors, and can detect that the length Lver of the antenna member 30 in the processing space 20a is longer or shorter than 3 [cm]. The length adjusting means 31 sends out the antenna member 30 by the length adjusting means 34 when the detection result of the length detecting means 32 and 33 is shorter than the predetermined length (in this case, 3 [cm]). When the length is longer than the predetermined length, the length adjusting means 34 pulls out the antenna member 30 to maintain the predetermined length.

As shown in FIG. 2 (F), when the plasma 50 is moved and maintained above the holding container 40, if the lower end portion of the plasma 50 is near the upper end of the antenna member 30, The plasma particles are accelerated by the concentrated electric field, whereby further ionization proceeds, and the plasma 50 is maintained at a higher temperature and higher density, and the plasma 50 is maintained.
FIG. 2G shows another embodiment of the antenna member 30. The antenna member 30 is accommodated in a cylindrical cover 36 (for example, composed of glass, ceramic (Al ₂ O ₃ ), etc.). . 2H is a cross-sectional view of FIG. 2G cut along a plane passing through the axis of the antenna member 30. FIG. In this case, if nitrogen gas or the like is supplied from below the cylindrical cover 36, melting or evaporation of the tip of the antenna member 30 can be suppressed. In the cross section shown in FIG. 2H, the antenna member 30 and the bottom member 35 are not in contact, but the antenna member 30 and the bottom member 35 are in contact with each other (grounded).

● [Addition and effect of second antenna member (Fig. 3)]
As described above, if the antenna member 30 is used, the plasma 50 can be ignited and maintained at atmospheric pressure. However, in order to further improve the ignitability of the plasma 50, the second antenna member 30H is added. It is preferable.
Next, the structure and arrangement of the second antenna member 30H will be described with reference to FIGS.
The shape and material of the second antenna member 30H are the same as those of the antenna member 30. However, when the length Lhor was set to λ as the wavelength of the microwave, it was found from experiments that a good result was obtained when the length Lhor was set to ¼ to ½ of λ (improved ignitability).

The second antenna member 30 is disposed substantially horizontally on a dielectric 43 (for example, a dielectric having a high melting point (1000 [° C.] or higher) such as powder or solid ceramic (Al ₂ O ₃ ), brick, etc.) is preferable. Just do it. In this embodiment, since powdered alumina is used for the dielectric 43 (base portion), the dielectric 43 is placed in the container 42. However, the container 42 is not necessary when plate-like ceramics, bricks, or the like are used. It is.
Then, the electric field of the microwave is concentrated on both ends of the second antenna member 30H placed on the dielectric 43 (base portion) having a large dielectric constant, the gas is ionized, and the plasma 50 is ignited.

Next, how the plasma 50 is generated when the second antenna member 30H is added will be described with reference to FIGS.
The second antenna member 30 </ b> H is disposed so as to lie on the dielectric 43 and is placed at an arbitrary position in the holding container 40. Then, when the microwave is output from the microwave generation means 10 in the plasma generation apparatus (added the second antenna member 30H) in the atmospheric pressure shown in FIG. 1, first, the second antenna member 30H generates the microwave. The electric field at the tip is concentrated (FIG. 3C), and gas in the atmosphere is ionized by this electric field, and the plasma 50 is ignited (FIG. 3D). When ionization further proceeds and the volume of the plasma 50 increases, the plasma 50 eventually moves above the holding container 40 by buoyancy (FIG. 3E). If the microwave output is continued in this state, the plasma 50 is maintained at the destination. When the plasma 50 is maintained, the plasma particles are accelerated by an electric field concentrated at the tip of the antenna member 30, thereby further ionization is promoted, the plasma 50 is increased in temperature and density, and the plasma 50 is maintained. The antenna member 30 contributes to the maintenance of the plasma 50.

Although glass is used as the material of the holding container 40, a thin glass (about 1 [mm] to 2 [mm]) has a smaller temperature difference between the inside and the outside than a thick glass. The experimental results showed that there was little distortion and good durability. In addition, it was confirmed that the shape of the holding container 40 is an axially symmetrical bowl-shaped (hemispherical) shape having no corners and better thermal strain uniformity and better durability.
In order to further improve the durability of the holding container 40, as shown in FIG. 3 (F), the holding container 40 has a double structure (a holding container having a small diameter is placed inside a holding container having a large diameter). A cooling fluid (cooling gas or the like) is preferably allowed to flow through the gap S. Note that the bottom surface of the holding container 40 is open, and the holding container is covered so as to cover the antenna member 30 standing on the conductor forming the bottom surface of the processing space 20a and the mounted second antenna member 30H. 40 is covered.

◆ [Second Embodiment (FIG. 4)]
FIG. 4 shows a schematic configuration diagram of an embodiment (second embodiment) of a plasma generation apparatus under atmospheric pressure according to the present invention. The second embodiment shows an example of a plasma generation apparatus in an atmospheric pressure that can generate and maintain a plasma by continuing a microwave having a relatively small output of, for example, less than 10 kW for several hours. (The output of each microwave generating means 10 is about 1 kW each).
In the second embodiment, the waveguide path for guiding the microwave from the microwave generation means 10 to the housing 20 is omitted from the first embodiment, and the microwave generation means 10 is directly provided in the housing 20. However, the configuration shown in the first embodiment is a simplified configuration. For this reason, in the second embodiment, the circulator 11, the coupler 12, and the matching unit 13 are omitted from the first embodiment. In the second embodiment, one or more microwave generating means 10 are provided.
Further, the microwave generation means 10 is provided with the microwave generation means 10 so that the microwave generation means 10 does not receive the microwave output by itself and the microwave output from other microwave generation means 10 is not received. Correspondingly, a reflecting member 10R is provided. The reflecting member 10R is also used for diffusing the output microwave.
Other configurations (such as the holding container 40 and the antenna member 30) are the same as those in the first embodiment, and thus description thereof is omitted.

◆ [Industry application example]
Next, an example in which the above-described plasma generation apparatus at atmospheric pressure is applied to industry will be described.
[Example 1: Heat treatment apparatus for gas to be treated (FIG. 5)]
FIG. 5 shows an example in which a gas to be treated (such as a harmful gas generated in manufacturing) is applied to a heat treatment apparatus that performs heat treatment (decomposition) at a high temperature of plasma, and is applied to the plasma generation apparatus at atmospheric pressure shown in FIG. On the other hand, the holding container 40 is different (the microwave generating means 10, the circulator 11 and the like are not shown). In this embodiment, a substance having a mass smaller than that of the atmosphere is supplied from below and recovered from above.
The holding container 40 has a substantially cylindrical shape, the upper part is set in a spherical or hemispherical shape, and a hole 41 of a predetermined size is formed. A discharge pipe 43 b is connected to the hole 41. Further, the holding container 40 is provided to be inclined at a predetermined angle θ1.
With the above configuration, the vertically long plasma 50 is generated and maintained in the holding container 40, and the gas to be processed is reacted (heat-treated) over a relatively long distance. The predetermined angle θ1 is set according to the time for heat-treating the gas to be processed. The size of the hole 41 is set according to the output from the microwave generation means 10, the volume of plasma to be generated, the capacity and diameter of the holding container 40, and the like.
Below the holding container 40, an introduction pipe 43a for introducing a gas to be processed is provided. The gas to be treated is introduced into the holding container 40 from the introduction pipe 43a, is heat-treated (decomposed) by the plasma 50, and is discharged from the discharge pipe 43b. In addition, if the auxiliary introduction pipe 43c (indicated by a dotted line in FIG. 5) in which the introduction pipe 43a is extended to the vicinity of the center of the plasma 50 is provided in the holding container 40, the gas to be treated can be more reliably heat-treated. preferable.
This enables a very high temperature heat treatment (for example, 6000 [° C.] or higher) with the plasma 50, compared to the heat treatment with a conventional gas burner or the like (about 1000 [° C.]), and the decomposition of the gas to be treated is more reliable. Moreover, it can be performed in a shorter time.

[Embodiment 2: Heat treatment apparatus for material to be treated (powder substance), synthesis of material, composition modification, etc. (for example, synthesis of plural kinds of materials at high temperature) (FIG. 6)]
FIG. 6 shows an example in which a material to be treated (powder material that requires high-temperature treatment) is applied to a heat treatment apparatus that performs heat treatment (such as synthesis of useful components) at a high temperature of plasma. The holding container 40 is different from the generation device (the microwave generation means 10, the circulator 11 and the like are not shown). In this embodiment, a substance having a mass larger than that of the atmosphere is supplied from above and recovered from below.
A supply pipe 44b for supplying a material to be processed is connected to the hole 41 above the holding container 40, and a pre-treatment storage unit 44a for storing the material to be processed before heat treatment is provided above the supply pipe 44b. Yes.
Below the holding container 40 is connected a recovery pipe 44c for recovering the material to be treated that has been heat-treated by the plasma 50 (synthesis of useful components), and the end of the recovery pipe 44c is located at the position of the post-treatment storage section 44d. Is arranged.
The substance to be treated falls from the pre-treatment storage unit 44a via the supply pipe 44b into the holding container 40, is heat-treated by the plasma 50, and is stored in the post-treatment storage unit 44d from the recovery tube 44c. In addition, when an auxiliary guide member 44e (indicated by a dotted line in FIG. 6) is provided in the holding container 40 so as to guide the material to be treated that has been heat-treated and dropped to the recovery tube 44c, the material to be treated is provided. Can be efficiently recovered.
As a result, a very high temperature heat treatment (for example, 6000 [° C.] or more) by the plasma 50 can be performed with respect to the heat treatment by a conventional gas burner or the like (about 1000 [° C.]), and the heat treatment of the material to be treated can be performed more reliably. Moreover, it can be performed in a shorter time.

● [Example 3: laboratory equipment, toy (FIG. 7)]
FIG. 7 shows a microwave oven 10 and a housing 20 (processing space 20a) using a household microwave oven, and is composed of a holding container 40, an antenna member 30, and a bottom member 35 disposed in the processing space 20a. 2 shows an example of a plasma generation support device in atmospheric pressure. In the example shown in FIG. 7, the second antenna member 30H, the container 42, and the dielectric 43 are added, but these may be omitted. In this embodiment, the hole 41 of the holding container 40 may be omitted because it is applied to a laboratory instrument or a toy.
The bottom member 35 is a plate-like member formed of a conductor (eg, iron, aluminum, etc.), and a holding portion 35a for fixing one end of the antenna member 30 (fixed substantially vertically in this embodiment). Is provided. The holding part 35a is also formed of a conductor.
The antenna member 30 is a conductor having a predetermined length (1/4 of the wavelength λ of the microwave, and approximately 3 [cm] in the case of using the microwave of the microwave oven), for example, the diameter is 0.5. [Mm] mechanical pencil lead is used. The antenna member 30 is fixed to the holding portion 35 a of the bottom member 35.

The second antenna member 30H has a second predetermined length (about 1/4 to 1/2 of the wavelength λ of the microwave, and about 3 to 6 [cm] when microwaves in the microwave oven are used)) For example, a mechanical pencil lead having a diameter of 0.5 mm is used. The second antenna member 30H is placed almost horizontally on the dielectric 43. The container 42 in which the dielectric 43 and the second antenna member 30 </ b> H are disposed is placed on the bottom member 35.
Then, the bottom member 35 on which the antenna member 30 and the second antenna member 30H are arranged is placed in a microwave oven, and the holding container 40 is covered from above the bottom member 35 (FIG. 7A).
Then, the plasma generation support apparatus in atmospheric pressure is arrange | positioned in the state shown in FIG.7 (B) in a microwave oven.
Note that the second antenna member 30H, the container 42, and the dielectric 43 may be omitted. Further, since the surface of the inside of the microwave oven is a conductor, the bottom member 35 may be constituted only by the holding portion 35a, and one end of the antenna member 30 in the processing space is in contact with the conductor (grounding). ).
Further, the upper part of the holding container 40 has a substantially spherical or substantially hemispherical shape, and a hole 41 having a predetermined size (diameter of about 3 [cm]) is provided in the upper part. This is as described in the second embodiment.

In the state shown in FIG. 7B, after placing the plasma generation support device in the atmospheric pressure in the microwave oven, when the microwave oven is turned on and microwaves are output, FIGS. As already described in the example shown in E), the plasma 50 is ignited, and the plasma 50 is maintained while the microwave output is continued.
For example, in a reactor of about 1 kW, when a glass container having a diameter of about 20 [cm] is used as the holding container 40 and the hole 41 is formed in a circular shape of about 3 [cm], air convection occurs in the holding container 40. It was confirmed by experiments that the generated plasma 50 rose to the upper part of the holding container 40 by buoyancy and was maintained there. The generated plasma 50 rises to the upper part in the holding container 40, but if the hole 41 has a diameter of about 3 [cm] or more, it is confirmed by experiments that the plasma moves upward but does not flow out. did. Further, when the hole 41 is smaller than about 3 [cm], the generated plasma 50 does not rise in the holding container 40 and stagnates at the ignited position (near the second antenna member 30H (antenna member 30)). It has also been confirmed by experiments that the generated plasma 50 is unstable (when the plasma 50 covers the second antenna member 30H (antenna member 30), the second antenna member 30H (antenna member 30) is microwaved. The gas is not ionized). Since the upper limit of the diameter of the hole 41 varies depending on the diameter of the holding container 40 and the like, it is preferable to determine the set value of the diameter of the hole 41 through experiments or the like.

  As described above, in the casing 20 surrounded by the conductor, the inside is in the processing space 20a having the atmospheric pressure, and the length in the processing space 20a is a predetermined length (1/4 of the wavelength of the microwave). If the antenna member 30 is erected so that one end in the processing space 20a is in contact with the conductor and microwaves are irradiated into the processing space 20a, the atmospheric pressure can be increased. Can generate plasma. Further, if the holding container 40, the second antenna member 30H, and the like are further added, the ignition, high temperature, high density, and maintenance of the plasma 50 can be performed more stably.

The method and apparatus for generating plasma in the atmospheric pressure of the present invention are not limited to the method, configuration, structure, material, shape, size, etc. described in the present embodiment, and are various within the scope not changing the gist of the present invention. Can be changed, added, or deleted.
The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.
In this embodiment mode, microwaves are used to generate plasma, but various radio waves can be used.
As the material of the holding container 40, a material having relatively high heat resistance can be used in addition to glass and ceramic.

It is a figure explaining the schematic block diagram of 1st Embodiment of the plasma production apparatus in the atmospheric pressure of this invention. It is a figure explaining a mode that the structure and arrangement | positioning of the antenna member 30, and the plasma 50 are produced | generated. It is a figure explaining a mode that the structure and arrangement | positioning of the 2nd antenna member 30H, and the plasma 50 are produced | generated. It is a figure explaining the schematic block diagram of 2nd Embodiment of the plasma production apparatus in the atmospheric pressure of this invention. It is a figure explaining the example which applied the plasma production apparatus in atmospheric pressure to the heat processing apparatus of to-be-processed gas. It is a figure explaining the example which applied the plasma production apparatus in atmospheric pressure to the heat processing apparatus of a to-be-processed substance. It is a figure explaining the schematic block diagram of the plasma production assistance apparatus in the atmospheric pressure of this invention. It is a figure explaining the conventional plasma generator in atmospheric pressure.

DESCRIPTION OF SYMBOLS 10 Microwave generation means 10a Output control means 10b Temperature detection means 11 Circulator 12 Coupler 13 Matching device 14 Horn 20 Case 20a Processing space 30 Antenna member 30H Second antenna member 31, 34 Length adjustment means 32, 33 Length detection Means 40 Holding container 41 Hole 50 Plasma

Claims (2)

A processing space surrounded by a conductor and having an atmospheric pressure inside,
Microwave generation means;
A first antenna member having a first predetermined length having conductivity and a substantially columnar shape;
A second antenna member having a second predetermined length having conductivity and a substantially columnar shape;
A base composed of a heat-resistant dielectric,
A plasma generation device in atmospheric pressure, comprising a holding container for holding the generated plasma,
The microwave generation means irradiates the processing space with microwaves,
The first antenna member is provided so that one end in the processing space is in contact with the conductor, and the length in the processing space is a first predetermined length,
The holding container has a substantially spherical or hemispherical upper part, and a hole of a predetermined size is provided in the upper part, and is disposed in the processing space so as to cover the first antenna member. And
The base is disposed in the holding container;
The second antenna member is disposed substantially horizontally on the base portion.
Plasma generator at atmospheric pressure. A plasma generation support device in atmospheric pressure, which is surrounded by a conductor and arranged in a processing space of atmospheric pressure, and generates plasma by irradiating microwaves,
The upper part has a substantially spherical or substantially hemispherical shape, and a hole of a predetermined size is provided in the upper part to hold the generated plasma,
A flat bottom member having electrical conductivity;
A first antenna member having a first predetermined length having conductivity and a substantially columnar shape;
A second antenna member having a second predetermined length having conductivity and a substantially columnar shape;
A base portion made of a heat-resistant dielectric,
The bottom member is disposed in the holding container;
The first antenna member is disposed in the holding container with one end fixed to the bottom member,
The base is disposed in the holding container;
The second antenna member is disposed substantially horizontally on the base portion.
Plasma generation support device at atmospheric pressure.

Images