JPH043254B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a reactor for reacting raw materials that can be substantially gas-phase flowed, such as gas or liquid or solid fine particles suspended in the gas phase. More specifically, the present invention relates to a reactor equipped with a flow control system having a contraction/expansion nozzle.

In this specification, a contracting/expanding nozzle is one in which the opening area is gradually narrowed from the inlet side toward the middle part to form a throat, and the opening area is gradually expanded from this throat toward the outlet. Refers to a nozzle.
In addition, reactions include not only chemical reactions, but also changes in physical properties that are not accompanied by chemical reactions, such as phase changes in raw materials between gas, liquid, and solid phases, cluster formation, and activation of raw materials. It is something that

[Prior Art] Conventionally, an apparatus for producing amorphous SiO is known in which a wide-spread nozzle is provided between a means for generating SiO vapor and a collection box (Japanese Patent Publication No. 59-50601). This device injects the generated SiO vapor through a wide-spread nozzle into a collection box in a nitriding, carbonizing, or oxidizing atmosphere, causing it to expand adiabatically. is generated.

The diverging nozzle in the above device uses the fact that the flowing gas phase is rapidly cooled due to adiabatic expansion as it flows, and rapidly cools the flowing SiO, so that the SiO becomes Si and SiO ₂
This prevents it from decomposing. In addition, by utilizing the fact that the wide-divergent nozzle can accelerate the flowing gas phase to supersonic speed and has a wide speed adjustment range for the flowing gas phase, it is possible to obtain an amorphous shape.
This is to adjust the particle size of SiO. That is, the wide-spread nozzle in the above-mentioned apparatus is used as a means for suppressing the reaction of the raw material until the raw material SiO is introduced into the collection box that is the reaction field, and as a means for adjusting the particle size of the amorphous SiO produced. It is not used as a flow control system to bring raw materials or reaction products into a flow state that is easy to process.

[Problems to be Solved by the Invention] By the way, it is not possible to use a wide-spread nozzle to quickly cool the product to a temperature suitable for suppressing the reaction or to accelerate the product to a speed suitable for adjusting the product to a desired particle size. It is independent of the flow state of the gas phase flowing through the nozzle.

When the ratio of the pressure in the upstream chamber and the pressure in the downstream chamber is greater than or equal to the critical pressure ratio, the gas phase flow ejected from the wide-spread nozzle becomes a decelerated flow and is diffused after ejection, causing the ejection speed to exceed the speed of sound. Nor. When the pressure at the throat of the divergent nozzle becomes less than the critical pressure ratio, the ejection velocity from the divergent nozzle can be ultrasonic, but
The state of the flow ejected from the wide-spread nozzle is determined by the pressure P _j of the gas phase flow at the time of ejection and the pressure P on the downstream side of the wide-spread nozzle.
depends on whether or not they almost match. P _j =
When P, there is proper expansion; when P _j > P, there is insufficient expansion.
When P _j <P, it is called overexpansion. In the case of proper expansion, the gas phase flowing through the divergent nozzle is ejected as a flow having a substantially uniform velocity distribution in the cross-sectional direction along the direction of the outlet wall surface of the divergent nozzle.
In addition, in the case of underexpansion or overexpansion, a decelerated flow is ejected and diffusion occurs.

However, as mentioned above, the diverging nozzle in the conventional device is used without regard to forming the appropriate expansion flow, and it is important to avoid the flow ejected from the diverging nozzle from becoming a diffusion flow. I can't. When such a diffusion flow occurs, for example, in the conventional apparatus described above, the SiO fine powder spreads throughout the collection box, and some of the SiO powder comes into contact with the inner wall surface of the collection box and remains attached thereto, or loses its activity. This causes problems such as a decrease in the yield of the reaction product and the mixing of unreacted substances into the reaction product. Furthermore, if the reaction product is sent as a diffusion stream, it is difficult to collect it at a desired position, which also causes a decrease in yield. Furthermore, depending on the type of raw material or reaction product, when the raw material or reaction product that has passed through the wide-spread nozzle is activated and collected by, for example, laser light irradiation or plasma, diffusion flow may be used. There are also problems in that it is difficult to efficiently provide such energy and it is difficult to provide a versatile reactor.

[Means for Solving the Problems] The means taken to solve the above problems will be explained with reference to FIG. 1, which corresponds to an embodiment of the present invention. The above-mentioned problems have been solved by using a reactor that can convert the flow of raw materials or reaction products into a beam.

In FIG. 1, for convenience of explanation, the upstream and downstream sides of the contraction/expansion nozzle 1 are connected to an upstream chamber 2 and a downstream chamber 3, respectively, which are closed systems. However, in the upstream and downstream sides of the contraction/expansion nozzle 1 in the present invention, if the pressure ratio P/P ₀ between the upstream pressure P ₀ and the downstream pressure P can be set to a pressure ratio below the critical pressure ratio,
It may be a closed system or an open system, and further may be a vacuum system or a pressurized system.

[Function] In the present invention, the raw material or the reaction product flows from the inlet 1a of the contraction/expansion nozzle 1 to the throat portion 1b.
It can be passed through the outlet port 1c and jetted out as an appropriately expanded flow. Here, the appropriate expansion flow is a flow ejected from the contraction/expansion nozzle 1, and the pressure P _j at the time of ejection is the pressure P on the downstream side of the contraction/expansion nozzle 1.
A flow that is approximately equal to

For example, assuming that the flow expands adiabatically in the contraction/expansion nozzle 1, the velocity of the flow is u, the sound velocity at that point is a, and the specific heat ratio of the flow is γ, the Matsuha number M reached by the flow is Pressure P ₀ and downstream chamber 3
It is determined by the following equation from the pressure P.

Note that the sound velocity a can be determined by the following equation, where T is the local temperature and R is the gas constant.

a=√ Furthermore, the following relationship exists between the opening area A of the outflow port 1c, the opening area A ^* of the throat portion 1b, and the reached Matsuha number M.

Then, from the pressure ratio P/P ₀ of the pressure P ₀ in the upstream chamber 2 and the pressure P in the downstream chamber 3, the Matsuha number M determined by equation (1)
When the opening area A of the outflow port 1c and the opening area A ^* of the throat portion 1b match the Matsuha number determined by equation (2), the flow becomes properly expanded. In this case, P/
P ₀ is less than the critical pressure ratio, and M is 1 or more. The velocity u of this flow can be determined using the following equation (3).

u=M(1+γ-1/2M ² ) ^-1/2 ...(3) When the flow ejected from the outlet 1c of the contraction/expansion nozzle 1 becomes a proper expansion flow, the flow ejected from the contraction/expansion nozzle 1
The flow has a substantially uniform velocity distribution in the cross-sectional direction along the inner wall surface direction of the outlet 1c, and is formed into a beam. Here, the beam refers to a jet stream that flows in a fixed direction with higher density and directivity than the surrounding space, and its cross-sectional shape is not limited. Since the flow is made into a beam and diffusion is minimized, the raw materials and reaction products ejected from the contraction/expansion nozzle 1 can be kept spatially independent without interference with the wall surface of the downstream chamber 3. This prevents negative effects from contact with walls. Furthermore, by collecting the particles on, for example, the substrate 4 while maintaining the beam-formed flow, it is possible to prevent the yield from decreasing due to diffusion. Furthermore, even when raw materials and reaction products are activated by, for example, laser light irradiation or plasma, by applying these energies to the beam-formed flow, it can be done efficiently without waste. can be done.

On the other hand, if the thermal energy of the flow is t and the kinetic energy is v, then t and v have the following relationship.

t ² /γ−1+1/2v ² = constant ... (4) Therefore, the temperature of the flow can be adjusted according to the speed of the flow to be beamed. In particular, in the present invention, since the flow is supersonic, the material It is possible to create a frozen state or a supercooled state for reaction products.

Equations (1) and (2) above hold true when the flow undergoes adiabatic expansion, but do not hold true when the flow generates heat or absorbs heat within the contraction/expansion nozzle 1. but,
Even in such a case, an appropriate expansion flow can be achieved by adjusting P/P ₀ and A/A ^* according to the amount of heat generated or absorbed.

Mass flow rate m of the flow passing through the contraction/expansion nozzle 1〓
is determined by the following equation (5), and assuming that the pressure P ₀ and temperature T ₀ of the upstream chamber 2 are constant, the throat part 1b
On the other hand, if the opening area ^{A* of} the throat portion 1b is constant, then the pressure in the upstream chamber 2 _P0
and temperature.

Therefore, it is easy to continuously obtain a constant amount of the reaction product, and it is also easy to supply raw materials in an amount commensurate with the amount of reaction.

[Embodiment] FIG. 1 is a schematic diagram of an embodiment of the present invention, in which 1 is a contraction/expansion nozzle, 2 is an upstream chamber, and 3 is a downstream chamber.

The upstream chamber 2 and the downstream chamber 3 are connected through a contraction/expansion nozzle 1, and the upstream chamber 2 includes a valve 5a for supplying raw material A and a pressure sensor _S1 for detecting the pressure inside the upstream chamber 2. is connected.

A valve 5b for supplying raw material B to react with raw material A is connected to the downstream chamber 3, and
At a position facing the outlet port 1c of the contraction/expansion nozzle 1, a base body 4 for collecting a reaction product C obtained by the reaction of raw materials A and B is provided.
The base body 4 is movably supported by a drive unit 10. Further, a pump 6 for evacuating the inside of the downstream chamber 3 is connected to the downstream chamber 3 via a valve 5c, and a pressure sensor S ₂ for detecting the pressure inside the downstream chamber 3 is further connected.

The contraction/expansion nozzle 1 is installed with an inlet 1a opened in the upstream chamber 2 and an outlet 1c opened in the downstream chamber 3. A pressure sensor _S3 for detecting the pressure of the flow at the time of ejection is connected near the outlet 1c.

When raw materials A and B are supplied while exhausting the inside of the downstream chamber 3 with the pump 6, the raw material A is ejected from the upstream chamber 2 through the contraction/expansion nozzle 1 and into the downstream chamber 3.
The reaction product C is collected on the substrate 4 by contacting and reacting with the raw material B inside. At this time, the pressure sensor
The pressure sensor is adjusted so that the pressure P _j detected by S ₃ and the pressure P detected by pressure sensor S ₂ are almost equal.
By adjusting the pressures P ₀ and P detected at S ₁ and S ₂ , the flow becomes a properly expanded flow and becomes a beam. Further, a contraction/expansion nozzle 1 may be provided in which the ratio A/A ^* of the opening area A ^* of the throat portion 1b and the opening area of the outlet 1c is adjusted in accordance with the required pressures _P0 and P.

Raw material A is ejected into the downstream chamber 3 as a beam stream, comes into contact with raw material B while flowing in the downstream chamber 3 as a beam stream, becomes a reaction product C, and is collected as is on the substrate 4. Therefore, the raw material A and the reaction product C are hardly diffused into the downstream chamber 3, and the reactant C can be continuously obtained with good yield. A part of the raw material B is discharged outside the system by the pump 6, but this can be recycled.

By the way, raw material A that becomes a beam-shaped flow,
It is necessary to cause the raw material B in the downstream chamber 3 to undergo a sufficient contact reaction. If the raw material B is a gas and the mean free path length of the gas molecules in the downstream chamber 3 is l, it can be considered that the gas molecules exist in the downstream chamber 3 at intervals of l. Therefore, assuming that the mean free path l of gas molecules in the downstream chamber 3 is constant,
The degree to which raw material A contacts molecules of raw material B while being transferred within downstream chamber 3 can be controlled by adjusting the length of the flow path within downstream chamber 3. This flow path length can be controlled by, for example, moving the base body 4 in the flow path direction using the drive unit 10. Furthermore, assuming that the flow path length in the downstream chamber 3 is constant,
The above control can also be performed by adjusting the mean free path length l of gas molecules.

Here, if the diameter of the gas molecules of the raw material B in the downstream chamber 3 is σ, and the number of molecules per unit volume is n, then the mean free path length l can be approximately determined by the following equation (6).

l=1/√2πnσ ² ...(6) Also, if the mass of the gas molecule is m, its density ρ
Since ρ=mn, the above equation (6) can be transformed into the following equation (6').

l=m/√2πρσ ² ...(6') In equation (6') above, m and σ are constant values determined by the type of gas, so l can be adjusted by ρ, and from this Therefore, the degree of collision between the molecules of raw material A and raw material B can be controlled. Furthermore, by keeping ρ constant, l can be kept constant.

On the other hand, ρ is determined by the following equation (7), where R is the gas constant and t' is the temperature in the downstream chamber 3.

ρ=P/Rt' (7) Therefore, ρ can be controlled by adjusting the pressure P or temperature t' of the downstream chamber 3.
Furthermore, as described above, if the temperature in the upstream chamber 2 is constant, the speed of the flow ejected from the same contraction/expansion nozzle 1 is determined by P/P ₀ . Therefore,
When controlling the gas molecule density ρ to be constant, P/
By keeping P ₀ constant, the same flow velocity can be maintained. In particular, when the active life of raw material A is short, the length of the flow path in the downstream chamber 3 that can flow within this life at a speed determined from A/A ^* and P/P ₀ is set, and the gas molecular density of raw material B is ρ. With the control of P/
By keeping P ₀ constant, raw material B can be brought into sufficient contact with raw material A in its active state.

As described above, the contraction/expansion nozzle 1 has an opening area gradually narrowed from the inlet 1a to the throat portion 1.
b, and the opening area gradually expands again to form the outflow port 1c.
As shown in the enlarged view, it is preferable that the inner circumferential surface of the outlet 1c is substantially parallel to the central axis. This means that the flow direction of the jet flow is the outlet 1c.
This is to make parallel flow as easy as possible since the direction is along the direction of the inner circumferential surface of. However, as shown in FIG. 2b, the angle α of the inner circumferential surface extending from the throat portion 1b to the outlet 1c with respect to the central axis is
If it is set to 7° or less, preferably 5° or less, the separation phenomenon is less likely to occur and the flow of the jet flow is maintained in a substantially straight line, so in this case it is not necessary to form the above-mentioned parallel portion. By omitting the formation of the parallel portion, the contraction/expansion nozzle 1 can be manufactured easily. Further, if the contraction/expansion nozzle 1 is made rectangular as shown in FIG. 2c, it is possible to eject the liquid in a slit-like flow.

Here, the above-mentioned separation phenomenon means that when there is a protrusion on the inner surface of the contraction/expansion nozzle 1, the boundary layer between the inner surface of the contraction/expansion nozzle 1 and the flowing fluid becomes large.
This is a phenomenon in which the flow becomes non-uniform, and the higher the speed of the jet flow, the more likely it is to occur. In order to prevent this peeling phenomenon, the above-mentioned angle α is preferably made smaller as the inner surface finish accuracy of the contraction/expansion nozzle 1 is inferior. The inner surface of the contraction/expansion nozzle 1 has three or more, preferably four or more, inverted triangular marks indicating surface finish accuracy as defined in JIS B 0601.
In particular, the peeling phenomenon at the enlarged part of the contraction/expansion nozzle 1 greatly affects the subsequent flow, so by determining the finishing accuracy with emphasis on this enlarged part, the production of the contraction/expansion nozzle 1 can be made easier. can. In addition, in order to prevent the occurrence of peeling phenomenon,
It is necessary that the throat portion 1b has a smooth curved surface so that the differential coefficient in the rate of change of cross-sectional area does not become ∞.

Examples of the material of the contraction/expansion nozzle 1 include iron,
In addition to stainless steel and other metals, a wide variety of materials can be used, including polyethylene fluoride, acrylic resin, polyvinyl chloride, synthetic resins such as polyethylene, polystyrene, and polypropylene, ceramic materials, quartz, and glass. This material may be selected by taking into consideration non-reactivity with raw materials A and B and reaction product C, processability, gas release properties in a reduced pressure system, and the like. Furthermore, the inner surface of the contraction/expansion nozzle 1 can be plated or coated with a material that is less likely to cause a reaction. A specific example is a polyfluorinated ethylene coating.

The length of the contraction/expansion nozzle 1 can be arbitrarily determined depending on the size of the device and the like. By the way, when the flow passes through the contraction/expansion nozzle 1, the thermal energy it possesses is converted into kinetic energy. By increasing the speed and reducing the thermal energy, it is possible to create a supercooled state. Furthermore, if the raw material A contains condensed components, it is also possible to actively condense them by the temperature drop and thereby form fine particles. Further, in this case, in order to perform sufficient condensation, it is preferable that the contraction/expansion nozzle 1 be long. On the other hand, when condensation occurs as described above, thermal energy increases and velocity energy decreases. Therefore, in order to maintain high-speed jetting, it is preferable that the condensing and expanding nozzle 1 be short.

As shown in FIG. 4, it is also possible to form a supply hole 9 closer to the inlet 1a than the throat 1b of the contraction/expansion nozzle 1 to supply other raw materials that react with the raw material flowing inside the contraction/expansion nozzle 1. . By keeping the opening position of the supply hole 9 in the contraction/expansion nozzle 1 sufficiently away from the throat portion 1b, disturbance of the flow ejected from the contraction/expansion nozzle 1 can be prevented.
Beam formation is maintained. If the contraction/expansion nozzle 1 is provided with such a supply hole 9, it is not necessary to supply and mix all the raw materials in the upstream chamber 2, for example, when two or more kinds of raw materials are reacted in a beam-shaped flow. It is possible to prevent the reaction from starting within the upstream chamber 2 and adhering to the wall surface thereof.

Further, the contraction/expansion nozzle 1 may have two or more throat portions 1b, 1b, . . . as shown in FIG. If a proper expansion flow is formed with such a multi-stage contraction/expansion nozzle 1, the flow will repeatedly accelerate and decelerate within the contraction/expansion nozzle 1, and the temperature of the flow will also repeatedly drop and rise accordingly. Therefore, it is also possible to promote reactions by utilizing such temperature changes.

If necessary, for example, the raw material A can be activated within the contraction/expansion nozzle 1 or after being ejected. To apply activation energy within the contraction/expansion nozzle 1, the contraction/expansion nozzle 1 is made of an insulator such as quartz, and microwaves are applied to generate plasma.
An example of this is to form the contraction/expansion nozzle 1 from a transparent material and irradiate the flow with light having various wavelengths such as ultraviolet, infrared, and laser light. Also, Figure 3 a, b
As shown in , the contraction/expansion nozzle 1 is formed of two halves 8a and 8b made of a good electrical conductor, which are combined through an insulating part 7 made of an electric insulator, and the two halves 8a and 8b are combined into a pair. Plasma can also be generated by applying high frequency or direct current to this electrode. When activating the beam after it is ejected from the contraction/expansion nozzle 1, light or plasma may be applied to the beam.

By tilting the contraction/expansion nozzle 1 vertically, horizontally, or horizontally or by making it possible to scan at regular intervals, the reaction product C can be collected in any desired range of the substrate 4. This is useful when forming a film on the surface of the substrate 4 with the reaction product C, and is particularly effective in combination with the rectangular nozzle shown in FIG. 2c.

If the base body 4 can be moved forward and backward in the direction of the contraction/expansion nozzle 1 by the drive unit 10, the timing until the raw material A reacts with the raw material B and is collected on the base body 4 can be adjusted. Therefore, even if the raw material or reaction product has an extremely short active life, it is possible to collect the raw material or reaction product in the active state by bringing the substrate 4 close to the activated position. Further, the substrate 4 can be heated or cooled to make it easier to collect. In particular, if the substrate 4 is cooled, the components can be condensed or solidified on the surface of the substrate 4 and collected.

The base body 4 can also be held movably or rotatably in the vertical and horizontal directions by the drive unit 10 so that the beam can be received over a wide range. Further, a long substrate 4 can be treated with the reaction product C by winding the substrate 4 into a roll and sending it out one after another to receive the beam. Furthermore, the treatment with the reaction product C may be performed while rotating the drum-shaped substrate 4.

It is also possible to provide a valve for opening and closing the contraction/expansion nozzle 1 and perform the reaction while opening and closing this valve intermittently. Under the same exhaust conditions, this intermittent opening and closing has the advantage that it is easier to maintain the downstream chamber 3 at a high vacuum. Conversely, when pressurizing the upstream chamber 2, it becomes easier to maintain this high pressure. When energy is applied for activation or the like within the contraction/expansion nozzle 1 or on the downstream side thereof, the energy can be applied without waste if energy is applied in synchronization with this intermittent opening/closing.

6a to 6d are each a schematic diagram of another embodiment of the invention.

In the case of a, when the raw material A supplied to the upstream chamber 2 is in the beam-formed flow state within the contraction/expansion nozzle 1 or after that, the physical properties of the raw material A have changed due to an activation reaction caused by energy application. Then,
It is collected on the base body 4 in the downstream chamber 3.

In the case of b, the raw materials A reacting with each other in the upstream chamber 2,
B is supplied, and by the time it passes through the contraction/expansion nozzle 1 and is collected on the substrate 4 in the downstream chamber 3, a reaction product C is generated and collected. In this case, at least the inner surface of the contraction/expansion nozzle 1 may be made of a catalyst that promotes the reaction of the raw materials A and B.

In case c, the raw material A supplied to the upstream chamber 2 is converted into a beam as it is and reaches the substrate 4 in the downstream chamber 3. The surface of the base 4 is a raw material B that reacts with the raw material A, and the raw material A collides with the surface of the base 4 as a beam, reacts with the raw material B, and is collected as a reaction product C. When a reaction is obtained on the surface of the substrate 4 in this manner, the kinetic energy of the flow turning into a beam and colliding with the substrate 4 at supersonic speed can be utilized for the reaction. Further, the raw material B on the substrate 4 may be a solid or a liquid impregnated into the substrate 4.

In case d, raw materials A and B are supplied to separate upstream chambers 2, 2, respectively, and are supplied to separate contraction/expansion nozzles 1, 1.
The beam is formed into a beam and flows into the same downstream chamber 3. Then, as the two beams intersect in the downstream chamber 3, the raw materials A and B react, and the reaction product C is collected on the substrate 4. In this way, raw material A
The reaction start position of and B can be set at any position within the downstream chamber 3.

[Effects of the Invention] According to the present invention, since the raw materials and reaction products are converted into a beam and transported in a fixed direction, a decrease in yield due to interference with the wall surface of the downstream chamber or flow diffusion can be minimized. Not only is it possible to carry out the reaction in a spatially independent area without any interference, it is also possible to obtain highly pure products due to the ideal reaction field. In addition, since the diffusion of the flow is suppressed, it is easy to apply the energy involved in the reaction, and it is easy to control the flow rate.This also makes it possible to apply just enough energy to match the amount of reaction, eliminating wasteful energy consumption. It can also be prevented.
In particular, in the present invention, not only raw materials but also reaction initiation means such as activation energy can be added continuously from the outside, so continuous treatment over a long period of time is possible and it is effective as an industrial mass production method. .

If the flow is properly expanded, large kinetic energy can be obtained from the beam-formed flow, and the irradiation area can be specified, making it possible to implant neutral particles that activate these, and to perform cutting and etching.

On the other hand, according to the present invention, raw materials and reaction products are transferred at supersonic speed, so even when raw materials and reaction products with extremely short active lives need to be received by the substrate in an active state, This is enough to satisfy me. In addition, since the flow can be frozen in the contraction/expansion nozzle 1, it is also possible to define the microscopic state of molecules in the flow and handle the transition from one state to another. In other words, it is possible to perform chemical reactions in the gas phase using a new method in which various energy levels of molecules are defined and energy corresponding to the levels is imparted. Furthermore, by providing a field for energy exchange different from conventional ones, it is also possible to easily create intermolecular compounds formed by relatively weak intermolecular forces such as hydrogen bonds and Van der Waals bonds.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the reaction apparatus according to the present invention, FIGS.
The figures are diagrams showing other embodiments of the contraction/expansion nozzle, respectively.
FIGS. 6a to 6d are schematic diagrams showing other embodiments of the present invention. 1: contraction/expansion nozzle, 1a: inlet, 1b: throat, 1c: outlet, 2: upstream chamber, 3: downstream chamber,
4: Base, 5a to 5c: Valve, 6: Pump,
7: Insulating part, 8a, 8b: Electrode, 9: Supply hole, 1
0: Drive unit, _S1 to _S3 : Pressure sensor.

Claims (1)

[Claims] 1. A reaction device comprising an upstream chamber and a downstream chamber connected via a contraction/expansion nozzle, the upstream chamber and the downstream chamber being connected to each other through a contraction/expansion nozzle, the upstream chamber and the downstream chamber being connected to each other through a contraction/expansion nozzle. pressure regulating means for regulating the pressure of the chamber and means for energizing the beam stream of the first material or supplying the second material and the energized or second material; 1. A reaction device comprising a base body for collecting the beam flow supplied with the beam flow.