JP3217415B2 - Powder dispersion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a powder capable of dispersing powder supplied from a powder supply source in a substantially constant amount as much as possible into primary particles as much as possible, and allowing the dispersed powder to be quantitatively sent to the outside by airflow. Body dispersion device, especially supply amount is, for example, several g / h to
The present invention relates to a powder dispersing apparatus suitably used when the amount is as small as several hundred g / h.

[0002]

2. Description of the Related Art Many fine powders (for example, those having a particle size of 30 μm or less) tend to form secondary particles because of their cohesiveness, and it is difficult to obtain a uniform dispersed state of the powder in the aggregated state. For this reason, when mixed with other objects as a mixed state in which the powder is sufficiently uniformly dispersed in the gas, or when used in applications where it is required to spray the powder,
Due to the cohesiveness, it is difficult to feed the primary particles as they are to the subsequent processing means, and as a result, the homogeneity and uniformity of the product are often impaired. For this reason, in the field of handling powder, dispersion of powder having cohesiveness is one of the major technical issues, and several dispersion apparatuses for dispersing powder have been proposed. For example, a method in which the powder conveyed by a screw feeder is brought into contact with a number of rotating hard spheres to stir and disperse the powder, or an air flow is applied to the flowing powder to disperse the aggregated powder. 2. Description of the Related Art An airflow type powder dispersing apparatus is conventionally known.

[0003]

However, the former dispersing apparatus has a relatively large moving part and is suitable for mass processing of powder having a large particle diameter. It is not necessarily effective as an apparatus for dispersing the body.

Some of the latter air-flow type powder dispersing devices can provide high dispersing ability, but do not always consider the time-dependent quantitative feeding performance, and disperse the dispersed powder into primary particles. It is not suitable as a powder dispersing apparatus for supplying a fixed amount while maintaining the state.

An object of the present invention is to solve the problems of the conventional powder dispersing apparatus and to disperse the agglomerated or easily agglomerated powder in the state of primary particles as much as possible. An object of the present invention is to provide a powder dispersing apparatus capable of stably supplying a dispersed powder to other subsequent processing means while maintaining a quantitative property without impairing a state of dispersion.

[0006]

In order to achieve the above object, the present inventor has completed the invention described in each of the claims.

The present invention typically provides a powder storage tank, a powder dispersing section for dispersing the powder sent from the powder storage tank, and a connection between the powder storage tank and the powder dispersing section. A cylindrical passage;
A screw that is provided along the cylindrical passage and feeds the powder from the powder storage tank to the powder dispersion portion, and is provided at a tip of a shaft facing the powder dispersion portion of the screw so as to partially protrude from the cylindrical passage. It is, and extends radially outward planted radially from the shaft
A rotating brush having a large number of needle-like members projecting out, and the powder dispersing portion faces a distal end opening of the cylindrical passage, and a powder dispersing chamber from which a distal end of the rotating brush projects, the gas flow for powder dispersion and transport distally from radially outward periphery of the rotary brush annularly through between the needle-like member and a pumping supplying pressurized gas supply means, above the powder dispersing chamber
The root side of the rotating brush opposite to the axial end of the rotating brush
The powder is fed into powder dispersing chamber through axially from, characterized in that the powder delivery pipe for feeding the powder dispersion outdoor together with the gas fluid flow is connected.

[0008] With the above structure, the powder conveyed by the screw feeder is dispersed by the rotating brush, and the pulsation of the discharge by the screw is eliminated. The powder passing through the gap between the shaped members can be further dispersed.

Further, in order to achieve the object, the device of the present invention can adopt the following configuration in addition to the above configuration.

[0010] 1. In order to be able to blow a gas having a flow rate suitable for the powder to be processed into the rotary brush, for example, a flow rate adjusting means for changing a sectional area of a gas passage for blowing a pressure gas is provided.

2. The inside space of the powder dispersion chamber is made as small as possible to reduce the amount of powder adhering to the inner wall of the powder dispersion chamber, and to prevent the concentration of the supplied powder from becoming unstable due to the re-scattering of the adhered powder. In order to prevent this, the powder dispersion chamber is formed as a truncated conical space in which the diameter becomes narrower in the flow direction of the powder, and the angle between the generating line of the truncated cone and the axis is in a range of 30 degrees or more. The shape of the space may be a cylindrical space corresponding to the case where the angle is 90 degrees.

3. When sending the powder to the outside of the powder dispersion chamber through the powder transport pipe, an air flow containing the dispersed powder is provided in the middle of the powder transport pipe so that the powder is transported while maintaining a good dispersion state. A pipe diameter portion having a flow velocity of 20 m / s or more is provided to achieve dispersion by collision between powders and prevent reagglomeration.

4. The length of the powder transport tube is set to be 10 times or more the pipe diameter so that the powder moving in the powder transport tube collides with the inner wall of the transport tube during the movement and is completely dispersed.

5. In the powder storage tank, the powder is forcibly pushed between the screws in order to prevent the aggregated powder from forming a bridge between the blades of the screw or the like and impairing the quantitative transport of the powder. For this purpose, for example, the stirring blade is made of an elastic material such as rubber, and is provided at a position where the rotating tip of the stirring blade elastically contacts the upper peripheral edge of the screw. Alternatively, the stirring blade is made of a rigid body such as a metal, and is provided at a position where the rotating tip of the stirring blade is as close as possible to the upper peripheral edge of the screw.

6. A structure in which a powder storage tank, a cylindrical passage, a screw feeder, and the like are housed in a pressure vessel. This eliminates the problem of gas leakage from the pressure seal of the bearing, the pinhole of the weld, etc., or the gas atmosphere of a dispersing aid such as methanol or ethanol in the pressure vessel.
Allows for better dispersion of the cohesive powder.

[0016]

According to the powder dispersing device of the present invention, the agglomerated or easily agglomerated powder conveyed by the screw feeder is promoted by the rotating brush and the airflow blown into the rotating brush to promote the dispersion. The powder can be sent to the subsequent processing means in the form of primary particles together with the airflow.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Embodiment 1 FIG. 1 is a sectional view showing a schematic configuration of an apparatus according to this embodiment, and FIG.
FIG. 2 is a sectional view showing a schematic configuration of a powder dispersion section of the apparatus. In these figures, reference numeral 16 denotes a powder storage tank, which forms an upper lid (not shown) provided at an upper portion or a pressure vessel sealed with an oil seal or the like. Powder inlet (not shown) is provided. Reference numeral 8 denotes a stirring shaft, which is provided in the powder storage tank 16 in the horizontal direction, and the stirring blades 7 are provided at a plurality of positions in the axial direction. The stirring shaft 8 is driven by the external motor 2 via the gear 4 and rotates to stir and mix the powder in the powder storage tank 16. The stirring blade 7 is made of, for example, an elastic body such as rubber, and is provided at a position where the rotating tip of the stirring blade elastically contacts an outer peripheral edge of a screw 21 of a screw feeder 22 described later. It is forcibly pushed between the screws 21.
With such a structure, it is possible to prevent a powder having a low bulk specific gravity or a powder having a high cohesiveness from forming a bridge between screws and the like, so that the powder cannot be quantitatively fed from the screw feeder 22 with time. are doing.

The above screw feeder 22 is
The shaft 20 is rotatably driven by the motor 2, provided below the powder storage tank 16 and across the powder storage tank 16. 3 is a control device for the motor 2, 6 is a shaft 2
0 bearing.

Reference numeral 23 denotes a casing as a cylindrical passage connecting the opening at the lower part of the side wall of the powder storage tank 16 and the powder dispersion section 18, and extends partway into the dispersion section 18 described later.

As shown in FIG. 2, the powder dispersing portion 18 is provided at the tip of the screw feeder 22 with the above-mentioned casing 23 and a screw 9 which is screwed into a screw 19 provided on a part of the casing 23 as an inner tube. The outer pipe 24 is provided with an outer pipe 24 fixed to the outside, and the powder transport pipe 13 is connected to the outer pipe 24. Inside the outer tube 24, a casing 23 is provided.
A powder dispersing chamber 26 is formed, which has an opening at one end and an opening at one end of the powder transport tube 13. The shaft 20 of the screw 21 extends into the powder dispersion chamber 26.

The other end of the powder transport tube 13 whose one end is open to the powder dispersion chamber 26 as described above is extended to a processing means (not shown) at a later stage.

A rotary brush 12 is provided at the tip of the shaft 20 of the screw 21 so that a part thereof projects from the casing 23 toward the powder dispersion chamber 26. The rotary brush 12 is formed by densely implanting a large number of needle-like members made of a relatively soft material such as nylon or a hard material such as a steel wire on the shaft. The tip of the needle-like member of the rotating brush 12 is provided so as to substantially contact the inner peripheral wall of the casing 23, and is driven to rotate as the shaft 20 rotates. The material, thickness, and density of the needle-shaped member can be appropriately selected depending on the type of the target powder and the like. The rotation speed of the rotating brush is also considered in consideration of the degree of dispersion. Can be determined as appropriate.

Reference numeral 11 denotes a gap formed between the distal end surface of the casing 23 and the bottom surface of the concave portion of the outer tube 24 in the dispersion section 18, and 27 denotes a gap between the outer periphery of the casing 23 and the inner periphery of the outer tube 24. It is a cylindrical gas passage formed therebetween.

In the dispersing section 18 of this embodiment configured as described above, the dispersing / transferring pressure gas is supplied from a pressure gas source (not shown) to the gas supply port 10, the gas passage 27, and the gap 11.
From the radial outside of the rotating brush 12 through the rotating brush 1
2 is characterized in that it is provided so as to blow out a pressurized gas and to disperse the powder passing between the needle-shaped members of the rotating brush 12 into primary particles.

Due to such a configuration, the powder dispersion chamber 26 provided near the bottom of the concave portion of the outer tube 24 forms a truncated conical space toward the tip (left side in the figure). Is provided. The frusto-conical tapered portion 25 (frustum-shaped bus bar) is provided at an angle of, for example, about 30 degrees with the axis of the rotating brush 12. This dispersion chamber 26
The volume of the dispersion chamber 26 is preferably small, and if the volume of the dispersion chamber 26 is large, the powder particles dispersed by the rotating brush 12 adhere to the inner wall of the dispersion chamber 26 before entering the powder transport tube 13 and are scattered again. Therefore, there arises a problem that the concentration of the dispersed powder to be fed is not constant. Therefore, it is desirable that the angle between the tapered portion 25 and the axis be in the range of 30 degrees or more, so that the powder flow is easy to flow and the internal volume of the dispersion chamber is kept small.

In this embodiment, a screw 9 is used as flow rate adjusting means for adjusting the flow rate of gas blown into the rotary brush 12.
By changing the screw fixing position of the outer tube 24 by means of (1) and (2), the sectional area of the gap 11 is adjusted, and the speed of the airflow blown into the rotating brush 12 can be adjusted.

Further, when the powder is sent to the outside of the powder dispersion chamber through the powder transport pipe 13, the powder is dispersed by collision of the powder to prevent reagglomeration and keep the powder in a good dispersion state. It is preferable that the powder transport pipe is provided with a pipe diameter portion at least in the middle where the gas flow containing the dispersed powder has a flow velocity of 20 m / s or more so that the powder is transported as it is.

Further, the problem of gas leakage from the pressure seal of the bearing or the pinhole of the welded part can be solved, or the pressure vessel can be made to have a gas atmosphere of a dispersing aid such as methanol or ethanol so that the cohesive powder It is possible to adopt a structure in which a powder storage tank, a cylindrical passage, a screw feeder, and the like are housed in a pressure vessel so as to enable better dispersion.

The operation of the apparatus according to the present embodiment will be described.
And is continuously discharged into the dispersion chamber 26 by being dispersed so as to be swept out by the rotating brush 12 provided at the tip of the screw 21. At this time, gas supplied by pressure from a pressure gas source (not shown) through the gas inlet 10 is blown into the rotating brush 12 (from the radial outside of the rotating brush 12 in this embodiment) through the gas passage 27 and the gap 11. Therefore, even if the powder is agglomerated, the powder is dispersed into the primary particles and sent out to the dispersion chamber 26, and a constant amount of the dispersed powder can be continuously transported with the airflow through the powder transport pipe 13 with time.

Embodiment 2 FIG. 3 is a sectional view showing a schematic configuration of an apparatus according to Embodiment 2, and the same elements as those in FIGS. 1 and 2 are denoted by the same reference numerals.

The present embodiment has a structure in which substantially the entire powder dispersing apparatus of the first embodiment is housed in a pressure vessel. However,
In this case, in the powder dispersing apparatus according to the first embodiment in which the powder is stored, it is preferable that the upper lid is open or the upper lid is provided with an opening.

In this figure, reference numeral 1 denotes a sealed pressure vessel, and the internal pressure of the pressure vessel 1 is determined by the internal pressure of the powder dispersing apparatus of the first embodiment housed therein (therefore, the pressure of the powder transport pipe 13). (Internal pressure). 1
Reference numeral 4 denotes a high-pressure gas supply pipe for maintaining the pressure vessel 1 at a high pressure, and reference numeral 15 denotes a gas exhaust pipe. A powder transport pipe 13 is led out of the pressure vessel 1 to the outside.

With such a structure, the high-pressure gas press-fitted from the air supply pipe 14 flows through the gas supply port 10 into the powder dispersion chamber 26 on the low-pressure side. Due to the pressure difference between the pressure vessel 1 and the powder dispersing apparatus, gas leakage from pressure seals (for example, the oil seal 5) of bearings such as the stirring shaft 8 and the screw 21 and a pinhole of a welded portion. There is an advantage that it is not necessary to consider the problem at all. Such a configuration does not hinder practical implementation because, for example, when the apparatus of the present invention is used for the purpose of dispersing an extremely small amount of powder as described above, the sealed container does not become large. Also, by putting a desiccant in the pressure vessel 1 to prevent the powder from absorbing moisture, or by introducing a dispersion aid such as methanol or ethanol into the pressure vessel 1 in the form of a liquid, these vaporized gases are reduced. Since the adhesive force between the powder particles is weakened, the cohesive powder can be better dispersed.

The apparatus of the present invention described above is, for example, a powder spraying machine for spraying powder to a mold of a powder compression molding apparatus to prevent the product from adhering, and a plasma spraying machine. Powder feeder for ultrafine particle manufacturing equipment, spacer sprayer for liquid crystal substrate, powder feeder for powder dry particle size analyzer,
It is suitably used as a powder dispersion device such as a sand plast device.

[0036]

According to the powder dispersing apparatus of the present invention, the following effects can be obtained.

1. Agglomerated or easily agglomerated powder is dispersed as much as possible into primary particles with a rotating brush and airflow,
While maintaining this dispersion state, the powder can be quantitatively supplied to the outside together with the airflow over time.

2. The speed of the air flow passing through the rotary brush can be adjusted only by changing the cross-sectional area of the gas passage by changing the screw fixing position of the outer tube externally fixed to the casing with a screw.

3. The powder dispersion chamber is formed as a truncated conical space in which the diameter becomes narrower in the flow direction of the powder, and the angle between the generating line of the truncated cone and the axis is set to 30 degrees or more, whereby the powder dispersion is performed. and minimize the internal space of the chamber, the dispersed powder to reduce the amount adhering to the powder dispersing chamber surface, the concentration of O Ri transport powder to re-entrainment of deposited powder becomes unstable Can be prevented.

4. By providing a pipe diameter portion in which at least an air flow containing the dispersed powder has a flow velocity of 20 m / s or more in the middle of the powder transport pipe, dispersion by collision of powders in the powder transport pipe can be achieved, and reagglomeration can be prevented. .

5. By adopting a structure in which the length of the powder transport tube is at least 10 times the pipe diameter, the probability that the powder collides with the inner wall of the transport tube increases, and the collision further disperses the powder. It can be transported with good dispersion.

6. By adopting a structure in which the entire powder dispersing device is housed in the pressure vessel, the problem of gas leakage from the pressure seal of the bearing or the pinhole of the welded part is solved,
Alternatively, the cohesive powder can be better dispersed by putting a dispersing aid such as methanol or ethanol in a liquid form in the pressure vessel.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an apparatus according to a first embodiment.

FIG. 2 is a cross-sectional view showing a schematic configuration of a powder dispersion section of the apparatus.

FIG. 3 is a cross-sectional view illustrating a schematic configuration of an apparatus according to a second embodiment.

[Explanation of symbols]

1: pressure vessel, 2: motor, 3: motor control device, 4: gear, 5: oil seal, 6: bearing, 7: stirring blade, 8:
Stirring shaft, 9: screw, 10: gas supply port,
11: gap, 12: rotary brush, 13: powder transport pipe, 14: air supply pipe, 15: exhaust pipe,
16: powder storage tank, 18: powder dispersion part, 19:
Screw, 20: shaft, 21: screw, 2
2: screw feeder, 23: casing, 24: outer tube, 26: powder dispersion chamber, 27
: Gas passage.

Continuation of the front page (72) Inventor Hideo Moriyama 2-12-3 Nishikata, Bunkyo-ku, Tokyo Nisshin Flour Milling Co., Ltd. Hongo Ryo Co., Ltd. (56) References JP-A-2-157703 (JP, A) Jpn. (JP, U) Japanese Utility Model 63-63117 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 4/00-4/04

Claims (4)

(57) [Claims] 1. A powder storage tank, a powder dispersion section for dispersing powder sent from the powder storage tank, a cylindrical passage connecting between the powder storage tank and the powder dispersion section, A screw is provided along the channel and feeds the powder from the powder storage tank to the powder dispersing portion, and is provided so as to partially protrude from the cylindrical passage at a tip of a shaft facing the powder dispersing portion of the screw, And a rotating brush having a large number of needle-like members radially implanted radially from the shaft and having a plurality of needle-like members. a powder dispersion chamber the tip of the brush protrudes, radially outward of the rotating brush
Square gas flow for powder dispersion and transferred distally through between the needle-like member from the surrounding annularly and a pumping supplying pressurized gas supply means, the axial tip of the rotary brush of the powder dispersing chamber
Characterized in that the powder transport tube for feeding the opposing powder is fed into powder dispersing chamber through the axial direction from the root side of the rotating brush the powder dispersion outdoor together with the gas fluid flow is connected Powder dispersing device. 2. The powder transportation pipe according to claim 1, wherein the powder transport pipe connected to the powder dispersion chamber is provided in the middle of the extending pipe.
A powder dispersing device, comprising a pipe diameter portion in which an air flow containing dispersed powder has a flow velocity of 20 m / s or more. 3. The powder dispersing device according to claim 1, wherein the length of the powder transporting tube connected to the powder dispersing chamber is at least 10 times the tube diameter. 4. The powder dispersing apparatus according to claim 1, wherein the powder storage tank, the cylindrical passage, and the screw are housed in a pressure vessel.