JPH05212678A - Stirring device of fine grain and method thereof - Google Patents

Abstract

PURPOSE:To detect an amount of fine grains in a mixing container so accurately by stirring resistance in a stirring means stirring the fine grains and supply them stably in the state that the fine grains stirred and mized intermittently or continuously in a uniform manner are mixed with gas. CONSTITUTION:A bimorph plate 35 is made so as to be used as a stirring and mixing means for stirring and mixing fine grains 14, and stirring and mixing operation is performed by vibrations in this bimorph plate 35. In succession, a detecting electrode 39 is installed in this bimorph plate 35 together with a driving electrode 38, and the extent of stirring resistance is detected by means of a detecting output being taken out through this detecting electrode 39. With this constitution, an amount of the fine grains 16 is detected, a supply of the fine grains 16 is feedback-controlled so as to become the set desired value, thus it is supplied as stirring and mixing them in a stirring container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirring and mixing apparatus for fine particles and a stirring and mixing method, and more particularly to an apparatus and method for uniformly stirring and mixing fine particles in a predetermined container.
The present invention relates to a stirring and mixing apparatus and method suitable for use in an apparatus for jetting loose abrasive grains at high speed for etching or deposition.

[0002]

2. Description of the Related Art Conventionally, an apparatus as shown in FIG. 6 has been used for jetting loose abrasive grains together with gas at a high speed by a nozzle to etch or deposit a workpiece.

This apparatus is provided with a hopper 50 for supplying fine particles composed of loose abrasive grains, the hopper 50 is connected to the inlet side of a screw conveyor 51, and the screw conveyor 51 is driven by a motor 52. There is.
The downstream supply port 53 of the screw conveyor 51 is connected to the inlet of the mixing container 54.

The mixing container 54 is supported by a support base 55, and a load cell 56 is interposed between the mixing container 54 and the support base 55. Further, the mixing container 54 is provided with a level switch 57. And load cell 56
And the level switch 57 are connected to the input side of the controller 58. This controller 58 allows the motor 5
2 is controlled.

When fine particles are mixed by such an apparatus, the fine particles in the hopper 50 are supplied into the mixing container 54 by the screw conveyor 51. Then, the load cell 56 detects the amount of fine particles in the container 54 based on its weight, and the load cell 56 controls the controller 5
The motor 52 is controlled via the switch 8. In addition, the level switch 5 controls the amount of fine particles in the mixing container 54.
7, the level switch 57 stops the supply of fine particles by the motor 52 when the amount of fine particles in the container 54 exceeds a predetermined value.

[0006]

Since the conventional mixing apparatus using such a load cell 56 is designed to detect the weight reduction value of the granular material per unit time, the mixing container 54 is externally charged. There is a drawback that powder particles cannot always be added. Moreover, while the fine particles are added from the hopper 50, it is necessary to interrupt the automatic control function of the constant quantity feeder once, and continuous operation cannot be performed.

Further, according to such a conventional mixing apparatus, when the supply amount of the fine particles is very small, it is difficult to control the actual supply amount of the fine particles which has changed due to the followability and disturbance. This is because the weight of the mixing container 54 is measured by the load cell 56, and it is difficult to control the supply amount.

The present invention has been made in view of the above problems, and it is possible to perform not only intermittent operation but continuous operation, and even when the amount of fine particles supplied is very small,
It is an object of the present invention to provide a stirring and mixing apparatus and a stirring and mixing method for fine particles, the supply amount of which can be easily controlled.

[0009]

According to a first aspect of the invention, in an apparatus for uniformly stirring and mixing fine particles in a predetermined container, the amount of fine particles in the container is detected by the stirring resistance of a stirring means for stirring the fine particles. It was done.

A second invention is the same as the first invention,
The stirring means is configured by a mechanical-electrical conversion element.

A third invention is the same as the second invention,
A common electrode is provided on one surface of the mechanical-electrical conversion element, a drive electrode and a detection electrode are provided on the other surface, and a drive voltage is applied between the common electrode and the drive electrode. At the same time, the stirring resistance is detected by the detection output obtained from the common electrode and the detection electrode.

A fourth aspect of the present invention is a method for uniformly stirring and mixing fine particles in a predetermined container, wherein fine particles are supplied into the container until the stirring resistance reaches an upper limit value and the stirring resistance reaches a lower limit value. Further, the fine particles are supplied from the inside of the container to the outside.

A fifth aspect of the present invention is a method for uniformly stirring and mixing fine particles in a predetermined container, wherein the mixed fine particles are continuously supplied from the container to the outside and the stirring resistance is controlled to be constant. However, the fine particles are supplied into the container.

[0014]

According to the first aspect of the invention, the amount of the fine particles in the container is detected by the stirring resistance of the stirring means for stirring the fine particles in the container.

According to the second invention, the fine particles are stirred and mixed in the container by the stirring means composed of the mechanical-electrical conversion element, and the amount of the fine particles in the container is detected by the stirring resistance.

According to the third aspect of the invention, by applying a drive voltage between the common electrode and the drive electrode of the electromechanical conversion element, the electromechanical conversion element vibrates to stir the fine particles in the container. .. Moreover, the stirring resistance of the mechanical-electrical conversion element is detected by the detection output obtained from the common electrode and the detection electrode.

According to the fourth aspect, the fine particles are supplied into the container until the stirring resistance of the stirring means in the container reaches the upper limit value. Further, the fine particles are supplied from the inside of the container to the outside until the stirring resistance of the fine particles in the container reaches the lower limit value.

According to the fifth aspect, the mixed fine particles are continuously supplied from the container to the outside, and new fine particles are supplied to the container so that the stirring resistance becomes constant. Thus, it becomes possible to continuously supply fine particles while feedback controlling the amount of fine particles in the container to a constant value.

[0019]

EXAMPLE FIG. 1 shows an agitating and mixing apparatus 41 for fine particles according to an example of the present invention. This device 41 is a device for uniformly mixing fine particles composed of loose abrasive grains for powder beam etching and powder beam deposition.

This device comprises a compressor 1 for compressing gas. The compressor 1 is connected to a high pressure supply pipe 2, and a pressure adjusting on-off valve 3 is connected to the high pressure supply pipe 2. A dryer 4 for heating and drying gas is connected to the downstream side of the on-off valve 3. The downstream side of the dryer 4 is connected to a pipeline having a pressure control valve 5 and a high pressure pipe 6.

A pressure adjusting valve 7 is connected to the high pressure pipe 6, and the pressure adjusting valve 7 is connected to a high pressure fluid supply chamber 9 via a joint 8. The upper part of the high-pressure fluid supply chamber 9 is separated from the particulate stirring and mixing chamber 11 by the filter 10. The fine particle stirring / mixing chamber 11 is composed of a mixing container including an upper lid 33 and a lower lid 34, and this container constitutes the central portion of the stirring / mixing device 41.

A filter 12 is attached so as to define a portion having a volume of about 1/3 above the mixing chamber 11. An exhaust pipe 13 is connected to the central closed space defined by the filter 12. An exhaust amount adjusting on-off valve 14 is connected to the exhaust pipe 13. The downstream side of the on-off valve 14 is connected to the exhaust pipe 15.

The fine particles 16 made of free abrasive grains in the mixing chamber 11 are sucked by the fine particle suction port 17. The suction port 17 is connected to the tip of a fine particle suction pipe 18. Further, the lower surface of the central closed space of the filter 12 constitutes a particulate collection plate 19, and the particulates collected here are supplied to the outside through the suction port 17 and the suction pipe 18.

An on-off valve 20 is connected to the suction pipe 18, and a downstream side of this on-off valve 20 is a particulate solid gas supply pipe 2.
It is connected to 1. The tip end of the supply pipe 21 is a suction nozzle 22 connected to the downstream side of the pressure control valve 5.
It is designed to be connected to. A fine particle solid-gas mixture flow 23 is formed in the nozzle 22, and the mixture flow 23 is jetted to the workpiece 25 by the jet nozzle 24. The workpiece 25 is a workpiece mounting table 26.
It is placed on top and is properly positioned.

The mounting table 26 on which the workpiece 25 is placed is covered with a dustproof case 27. Then, a fine particle recovery pipe 28 is formed so as to penetrate the case 27.
The recovery pipe 28 is provided with an opening / closing valve 29. The tip of the recovery pipe 28 is connected to a control pipe 30 arranged so as to surround the nozzle 24.

A fine particle supply pipe 31 is connected to the upper lid 33 of the container constituting the stirring and mixing device 41, and a fine particle supply adjusting valve 32 is connected to the fine particle supply pipe 31. Further, a plurality of bimorph plates 35 are arranged in the mixing chamber 11, and a base end side portion 36 of the bimorph plate 35 is cantilevered and arranged in the container.

The bimorph plate 35 constitutes a stirring means. As shown in FIGS. 2 to 4, a common electrode 37 is provided on one surface of the bimorph plate 35, and a driving electrode 38 and a detection electrode are provided on the other surface. And 39 are provided. That is, the bimorph plate 35 has a structure that serves both as a stirring means and a detection means.

The apparatus shown in FIG. 1 is a powder beam etching and deposition apparatus, and the compressor 1 constitutes a high pressure gas supply source. Air or dry nitrogen is used as the gas supplied here. The high-pressure gas is heated by the dryer 4 to remove moisture, and then divided into the suction nozzle 22 and the high-pressure pipe 6 and supplied. The gas on the high-pressure pipe 6 side is supplied to the high-pressure fluid supply chamber 9 of the fine particle stirring and mixing apparatus 41, and enters the mixing chamber 11 through the filter 10 made of cermet.
Then, in the mixing chamber 11, the high pressure gas air-vibrates the fine particles 16 to uniformly disperse and mix them.

The fine particles in the mixing chamber 11 are collected by the fine particle collecting plate 19, flow from the suction port 17 of the suction pipe 18 through the fine particle solid gas supply pipe 21, and the high pressure gas flow contains the fine particles at the outlet side of the suction nozzle 22. The solid-gas two-phase flow is mixed. The mixed flow 23 is jetted at a high speed onto the work piece 25 by the nozzle 24, and the work piece 25 is etched or deposited.

What is important here is the fine particle stirring and mixing chamber 11
In order to uniformly disperse and supply the fine particles 16 to the nozzle 24 at a constant flow rate inside the fine particle 1 in the mixing chamber 11,
6 is how to optimize the uniform dispersion.

Generally, when the particle diameter of the fine particles 16 is 10 μm or less, the fine particles adhere to the inside of the upper lid 33 or the lower lid 34 due to the aggregation of the fine particles, which makes it very difficult to stir and mix.

Therefore, in the apparatus according to the present embodiment, in order to solve this problem, one or a plurality of bimorph plates 35 are used, and the bimorph plates 35 each have a thickness of 100 to 500.
An AC voltage of 50 to 1200 Hz is applied. As shown in FIG. 1, since the supporting portion 36 of the bimorph plate 35 is cantilevered on the outer peripheral side of the mixing chamber 11, the free end side of the bimorph plate 35 vibrates in the plate thickness direction. Mixing chamber 11 due to vibration
The fine particles 16 therein are mixed by stirring.

Moreover, the stirring resistance of the bimorph plate 35 is detected by the detection voltage obtained by the common electrode 37 and the detection electrode 39. As is apparent from FIG. 4, the detection electrode 39 is formed on the back surface of the bimorph plate 35 and on the tip side thereof.

By using such a bimorph plate 35 to detect the stirring resistance by the detection voltage, it is possible to continuously detect the supply amount of the fine particles. That is, as shown by the curve in FIG. 3, since it is possible to obtain the supply amount of fine particles based on the static amount characteristics of the amount of fine particles and the detection voltage, it is convenient to freely set the upper and lower limit set values and target values. There is.

Next, the control operation of the amount of fine particles by this device will be described. The fine particles 16 are supplied into the mixing chamber 11 from the fine particle supply pipe 31 by the fine particle flow rate adjusting valve 32. In this case, when a driving voltage is applied to the bimorph plate 35, the detection voltage extracted from the detection electrode 39 is the curve of FIG. The value between the lower limit value and the upper limit value of is detected.

When the detection output detected by the detection electrode 39 exceeds the upper limit value, the adjusting valve 32 is closed. Then, a part of the high-pressure gas is made to flow to the suction nozzle 22 side through the pressure adjusting on-off valve 3, and the other part is made to flow from the high-pressure pipe 6 to the high-pressure fluid supply chamber 9 side. Further, the on-off valve 14 for adjusting the displacement is
When the fine particles are supplied from the fine particle supply pipe 31 and the fine particle supply adjusting valve 32 to the mixing chamber 11, it is opened, but in this case, the exhaust amount adjusting on-off valve 14 is adjusted to a constant exhaust pressure and the exhaust pipe 15 side. Play the role of flowing to. At this time, the on-off valve 14 may be opened and closed. Here, stirring and mixing are performed in the mixing chamber 11 based on the principle of a high-pressure air vibrator.

Next, the operation in the case where the set target value in FIG. 5, that is, an arbitrary value between the upper limit value and the lower limit value is set and the mixture is stirred and mixed, will be described. Here, the value shown as the set value (target value) in FIG. 5 is used. In this case, the fine particles 16 are supplied to the mixing chamber 11 via the regulating valve 32 and the fine particle supply pipe 31 as in the above-described operation. And the bimorph board 3
When the detection electrode 39 of No. 5 detects that the target value has been reached, the regulating valve 32 is closed and the supply of the fine particles 16 is stopped.

Next, the on-off valve 20 is opened, the fine particles 16 are sucked from the suction port 17 and mixed with the high-pressure gas by the suction nozzle 22, and the high-speed gas is jetted from the nozzle 24 to the workpiece 25 as a high-speed jet flow, and the workpiece surface is Etching or deposition processing.

In this case, the set amount of fine particles 16 is in the mixing chamber 1
A small amount is supplied to the nozzle 24 from inside 1. If it is left as it is, of course, the fine particles 16 are discharged to the lower limit value of the set value, the bimorph plate 35 detects the lower limit value, and the lower limit value is displayed. Therefore, the fine particles 16 are also supplied via the adjusting valve 32.

However, in this case, since the set value changes from the upper limit value to the lower limit value and the stirring amount of fine particles is different,
The quality of stirring and mixing is inferior to the method of feedback control to the target value.

FIG. 5 shows the detection voltage of the bimorph plate 35 due to the stirring resistance of the fine particles 16 when an AC voltage of 200 V and 50 Hz is applied to the drive electrode 38 of the bimorph plate 35 shown in FIGS. Here, the upper limit value, the target value, and the lower limit value are shown as set values on the curve of the detection voltage by the stirring resistance and the amount of fine particles.

When the target value shown in FIG. 5 is set, the stirring resistance of the fine particles 16 is detected from the detection voltage of the bimorph plate 35, and the high voltage gas is used to detect the stirring voltage of the bimorph plate 35 while the high voltage gas is used. Vibrate, stir and mix,
The particle supply adjusting valve 32 is adjusted to supply the mixing chamber 11 continuously by the amount of the particles discharged from the suction port 17 of the suction pipe 18 as a solid-gas two-phase flow containing particles. That is, the discharge amount and the supply amount of the fine particles in the mixing chamber 11 are determined by the bimorph plate 35.
It becomes equal by setting the target detection voltage of.

As a result, it is possible to uniformly disperse a fixed amount of the fine particles 16 in the mixing chamber 11, that is, a target set amount, and to stir and mix, and to generate a solid-gas two-phase flow containing the uniformly dispersed fine particles into a high pressure gas. It is possible to jet a solid gas jet containing high-speed fine particles from the nozzle 24 as the fine particle mixed flow 23, and uniformly etch or deposit the surface of the workpiece 25.

Since the bimorph plate 35 is provided with the driving electrode 38 and the detection electrode 39, there is a combined effect that the fine particles 16 are air-vibrated to be stirred and mixed, and also the bimorph plate 35 can be stirred. Therefore, the effect of stirring and mixing is doubled as compared with the conventional case.

[0045]

According to the first aspect of the invention, the amount of fine particles in the container is detected by the stirring resistance of the stirring means for stirring the fine particles. Therefore, the amount of fine particles can be detected without detecting the amount of fine particles in the container by weight, which is particularly suitable for supplying a minute amount of fine particles.

According to the second invention, since the stirring means is composed of the mechanical-electrical converting means, the fine particles in the container are stirred and mixed by the vibration of the mechanical-electrical converting means, and the stirring resistance thereof. As a result, the amount of fine particles is detected, which enables highly accurate detection.

According to the third aspect of the present invention, by applying a drive voltage to the common electrode and the drive electrode of the electromechanical conversion element, the conversion element vibrates and stirring and mixing are performed. Then, the stirring resistance is detected by the detection output obtained from the common electrode and the detection electrode. Therefore, such a mechanical-electrical detection means makes it possible to use both the stirring means and the detection means.

According to the fourth invention, the fine particles are supplied into the container until the stirring resistance reaches the upper limit value, and the fine particles are supplied from the container to the outside until the stirring resistance reaches the lower limit value. .. Therefore, it becomes possible to intermittently supply the solid-gas two-phase flow containing fine particles by adjusting the amount of fine particles to a value between the upper limit value and the lower limit value.

According to the fifth aspect, the fine particles mixed are continuously supplied from the container to the outside, and the fine particles are supplied into the container while controlling the stirring resistance to be constant. Moreover, it becomes possible to continuously mix and supply the fine particles with the gas while controlling the amount of the fine particles in the container to a constant value.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a stirring and mixing apparatus for fine particles according to an embodiment of the present invention.

FIG. 2 is a plan view of a bimorph plate.

FIG. 3 is a sectional view of a bimorph plate.

FIG. 4 is a bottom view of the bimorph plate.

FIG. 5 is a graph showing the relationship between the amount of fine particles and the detection voltage of a bimorph plate.

FIG. 6 is a front view showing a conventional stirring and mixing apparatus.

[Explanation of symbols]

 1 Compressor 2 High-pressure supply pipe 3 Pressure adjustment on-off valve 4 Dryer 5 Pressure adjustment valve 6 High-pressure pipe 7 Pressure adjustment valve 8 Joint 9 High-pressure fluid supply chamber 10 Filter 11 Fine particle agitation mixing chamber 12 Filter 13 Exhaust pipe 14 Open / close for exhaust amount adjustment Valve 15 Exhaust pipe 16 Fine particles 17 Fine particle suction port 18 Fine particle suction pipe 19 Fine particle plate 20 Open / close valve 21 Fine particle solid gas supply pipe 22 Suction nozzle 23 Fine particle solid gas mixture flow 24 Nozzle 25 Work piece 26 Work piece mounting stand 27 Dustproof Case 28 Particle recovery pipe 29 Open / close valve 30 Control pipe 31 Particle supply pipe 32 Particle supply adjustment valve 33 Mixing container (upper lid) 34 Mixing container (lower lid) 35 Bimorph plate 36 Support part 37 Common electrode 38 Drive electrode 39 Detection electrode 40 Base 41 Stirring Mixing Device 50 Hopper 51 Screw Conveyor 52 Mo 53 supply ports 54 mixing vessel 55 support stand 56 load cell 57 level switch 58 Controller

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[Procedure amendment]

[Submission date] August 21, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Added

[Correction content]

The mixing container 54 is supported by a support base 55, and a load cell 56 is interposed between the mixing container 54 and the support base 55. Further, the mixing container 54 is provided with a level switch 57. And load cell 56
A level switch 57 and is connected to the input side of the con preparative roller 58. The motor 52 is controlled by the controller 58.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

By using such a bimorph plate 35 to detect the stirring resistance by the detection voltage, it is possible to continuously detect the supply amount of the fine particles. Ie figure
As shown by the curve in FIG. 5 , since the amount of fine particles supplied can be obtained based on the static amount characteristics of the amount of fine particles and the detection voltage, there is the convenience that the upper and lower limit set values and target values can be freely set. ..

Claims (5)

[Claims] 1. An apparatus for uniformly stirring and mixing fine particles in a predetermined container, wherein the amount of fine particles in the container is detected by the stirring resistance of a stirring means for stirring the fine particles. Stirrer mixer. 2. The stirring and mixing apparatus for fine particles according to claim 1, wherein the stirring means is a mechanical-electrical conversion element. 3. A common electrode is provided on one surface of the electromechanical conversion element, and a drive electrode and a detection electrode are provided on the other surface of the electromechanical conversion element, and a drive electrode is provided between the common electrode and the drive electrode. The stirring / mixing device according to claim 2, wherein a stirring resistance is detected by a detection output obtained from the common electrode and the detection electrode while a voltage is applied. 4. A method for uniformly stirring and mixing fine particles in a predetermined container, wherein fine particles are supplied into the container until the stirring resistance reaches an upper limit value, and the inside of the container until the stirring resistance reaches a lower limit value. A method for stirring and mixing fine particles, characterized in that fine particles are supplied from the outside to the outside. 5. A method for uniformly stirring and mixing fine particles in a predetermined container, wherein the mixed fine particles are continuously supplied from the container to the outside, and the stirring resistance is controlled to be constant while controlling the container. A method of stirring fine particles, characterized in that fine particles are supplied into the inside.