JPH04150957A - Collision type jet mill and grinding method - Google Patents

Abstract

PURPOSE:To efficiently grind a thermoplastic resin by providing a plurality of powder raw material supply ports to an acceleration pipe and providing a secondary air introducing port between the powder raw material supply ports and the outlet of the acceleration pipe and forming the leading end part of the collision surface of a collision member into a specific conical shape. CONSTITUTION:In a grinding chamber 5, a collision member 6 for grinding the powder raw material injected from an acceleration pipe 2 by collision force is arranged in opposed relation to the outlet of the acceleration pipe 2 on the downstream side of the acceleration pipe 2 for feeding and accelerating the powder raw material by high pressure air. A plurality of powder raw material supply ports 1 are provided to the acceleration pipe 2 and a secondary air introducing port 11 is arranged between the plurality of the powder raw material supply ports and the outlet of the acceleration pipe 2. The leading end part of the collision surface of the collision member 6 is formed into a conical shape having a vertical angle of 110-180 deg.. As a result, a substance to be ground based on a thermoplastic resin such as a polyester resin or a styrenic resin can be efficiently ground.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an impingement type air jet pulverizer and a pulverizing method using a jet stream (high-pressure gas), and in particular to a toner used in an image forming method using electrophotography. The present invention also relates to a collision type air flow crusher and a crushing method for efficiently producing colored resin powder for toner.

[Prior Art] A collision-type air current pulverizer using a jet stream conveys a powder raw material by a jet stream, collides the powder raw material with a collision member, and crushes it by the impact force.

The details will be explained below based on FIGS. 8 and 9.

A collision member 6 is provided opposite the outlet 4 of the acceleration tube 12 to which the compressed gas supply nozzle 3 is connected, and the powder raw material is supplied to the middle of the acceleration tube 12 by the flow of the high-pressure gas supplied to the acceleration tube 12. Powder raw material 15 is introduced into the acceleration tube 12 from the port 1.
is sucked in and injected together with high pressure gas to collide with the collision member 6.
The object is made to collide with the collision surface of the object, and is shattered by the impact. When the powder raw material 15 is used for pulverizing to a desired particle size, a classifier is arranged between the powder raw material supply port 1 and the discharge port 9 to form a closed circuit, and the powder raw material is connected to the classifier. 15, the coarse powder is supplied from the powder raw material supply port 1, pulverized, and the pulverized material is returned to the classifier from the discharge port 9 to be classified again, and the fine powder is A finely ground product with the desired particle size is obtained.

However, in the above-mentioned conventional example, it is difficult to sufficiently disperse the powder raw material 15 sucked into the acceleration tube 12 in a high-pressure air flow, so that the powder flow jetting out from the acceleration tube outlet 4 has a dust concentration. It separates into a thick stream and a light stream.

Therefore, the powder flow that hits the opposing collision surfaces 17 becomes partial (local), resulting in a decrease in efficiency and a decrease in throughput. In addition, if you try to increase the processing capacity under these conditions, the dust concentration will increase in some areas, resulting in a further decrease in efficiency.Especially with resin-containing materials, the impact surface 1
7, which is not preferable.

Furthermore, when the powder raw material 15 containing a large number of coarse particles is sucked into the acceleration tube 12, the suction capacity of the powder raw material supply port 1 is reduced, resulting in a reduction in processing capacity.

In order to increase the efficiency of particle pulverization inside the acceleration tube 12,
A crushing tube equipped with a high-pressure gas supply pipe that blows out secondary high-pressure gas on the near side of the acceleration pipe outlet 4 was published in Japanese Patent Publication No. 46-22778.
It is proposed in the publication.

This is intended to promote collisions inside the accelerating tube 12, and is a useful means for a crusher that only performs crushing inside the accelerating tube 12. Impingement-type air flow crushers are not a useful method. This is because if secondary high-pressure gas is introduced to promote collision within the acceleration tube 12, the carrier airflow caused by the high-pressure gas introduced from the compressed gas supply nozzle 3 is obstructed, and the powder flow ejected from the acceleration tube outlet 4. speed will decrease.

Therefore, the impact force colliding with the collision member 6 decreases, and the crushing efficiency decreases, which is not preferable.

On the other hand, the collision surface of the collision member in conventional crushers is
As shown in Fig. 8 and Fig. 9, the direction of the high-pressure airflow (the axial direction of the accelerator tube) carrying the material to be crushed is perpendicular or inclined.
For example, a planar shape with an angle of 45° has been used (JP-A-57-50554 and JP-A-58-14).
(See Publication No. 3853).

However, in the case of the collision surface 17 perpendicular to the axial direction of the acceleration tube 12 as shown in FIG. Therefore, the concentration of powder (material to be crushed and crushed material) near the collision surface becomes high, resulting in good (poor) pulverization efficiency.

Furthermore, temporary collisions occur mainly on the collision surface, and secondary collisions with the crushing chamber wall 8 cannot be said to be effectively utilized.

Furthermore, when crushing thermoplastic resins, fusion and agglomerates are likely to occur due to local heat generation during collision (which makes stable operation of the equipment difficult and causes a reduction in crushing capacity. It was difficult to use it at a high concentration.

Furthermore, in the crusher shown in FIG. 9, since the collision surface 27 is inclined with respect to the axial direction of the acceleration tube 12, the powder concentration near the collision surface is lower than in the crusher shown in FIG. However, the collision force due to the high-pressure airflow is dispersed and reduced. Furthermore, it cannot be said that the secondary collision with the crushing chamber wall 8 is effectively utilized. For example, as shown in FIG. 9, if the collision surface is inclined at an angle of 45 degrees with respect to the accelerator tube, the above-mentioned problems are less likely to occur when pulverizing thermoplastic resin. However, since the impact force used for crushing during collision is small, and there is less crushing due to secondary collision with the crushing chamber wall 8, the crushing capacity is 1/2 to 1/2 compared to the crusher shown in FIG. The crushing capacity drops to 1.5.

Therefore, a crusher and a crushing method with good crushing efficiency are desired.

On the other hand, toners or colored resin powders for toners used in electrophotographic image forming methods usually contain at least a binder resin, a colorant, or magnetic powder. The toner develops the electrostatic charge image formed on the latent image carrier, and the formed toner image is transferred to a transfer material such as plain paper or plastic film, and is then transferred to a transfer material such as a heat fixing means, a pressure roller fixing means, or a heat pressure roller. The toner image on the transfer material is fixed to the transfer material by a fixing device such as a fixing means. Therefore, the binder resin used in the toner has the property of being plastically deformed when heat and/or pressure is applied.

Currently, toners or colored resin powders for toners are produced by melt-kneading a mixture containing at least a binder resin and a colorant or magnetic powder (further containing a third component if necessary), cooling the melt-kneaded mixture, and cooling the mixture. It is prepared by crushing a substance and classifying the crushed substance. Generally, when pulverizing a cooled material, it is coarsely (or medium) pulverized using a mechanical impact pulverizer, and then the coarse powder is pulverized into a fine pulverizer using an impingement airflow pulverizer that uses a jet stream. be.

In such a case, in the conventional collision type airflow crusher and crushing method as shown in FIG. 9, if the processing capacity is to be further improved, suction will be insufficient at the powder raw material supply port 1 provided in the acceleration tube 12. , or a fused substance is generated on the collision surface 27,
Stable production cannot be achieved. Therefore, in order to more efficiently produce toner or colored resin powder for toner used in electrophotographic image forming methods, an efficient impingement type air flow mill and a milling method that solve the above problems are desired. ing.

[Problems to be Solved by the Invention] In view of the above-mentioned conventional problems, it is an object of the present invention to efficiently crush materials mainly made of thermoplastic resins such as polyester resins or styrene resins. An object of the present invention is to provide an impact type airflow crusher for crushing and a crushing method.

In addition, the fusion of the material to be crushed and the crushed powder in the grinding chamber is prevented (and even when the throughput of the material to be crushed is increased, the fusion of the material to be crushed and the crushed powder is suppressed). The object of the present invention is to provide an impingement type air jet pulverizer and a pulverizing method that generate less aggregates and coarse particles.
An object of the present invention is to provide an impingement type air flow crusher and a crushing method capable of efficiently (finely pulverizing) resin particles having a diameter of 000 μm to an average particle size of 3 to 15 μm.

Another object of the present invention is to provide an impingement type air flow crusher and a crushing method that can efficiently produce toner or colored resin particles for toner used in copying machines and printers having heating and pressure roller fixing means.

[Means and effects for solving the problem] The present invention provides an acceleration tube 2 for transporting and accelerating powder raw material 15 using high-pressure gas.
In the collision type air flow crusher, a crushing chamber 5 is provided downstream of the accelerating tube 2, in which a crushing member 6 for crushing the powder raw material 15 ejected from the accelerating tube 2 by a collision force is arranged opposite to the accelerating tube outlet 4. A plurality of powder raw material supply ports are provided in the pipe 2, a secondary air introduction port is provided between the plurality of powder raw material supply ports and the acceleration tube outlet, and the tip portion of the collision surface of the collision member is at the top. The point is that the collision type air flow crusher has a conical shape with an angle of 11° or more and less than 180°.

In addition, a grinding method includes transporting and accelerating the powder raw material 15 using high-pressure gas in the acceleration tube 2, discharging it from the acceleration tube outlet 4 into the grinding chamber, and colliding it with the opposing collision member 6 to crush the powder raw material 15 into fine particles. In this step, the powder raw material is guided upstream of the acceleration tube 2 from a plurality of powder raw material supply ports, secondary air is introduced between the plurality of powder raw material supply ports and the acceleration tube outlet, and the A powder raw material 15 is crushed by colliding with a collision member 6 whose tip portion has a conical shape with an apex angle of 110° or more and less than 180°,
The present invention is also characterized by a pulverizing method in which the pulverized material after the collision is further pulverized by secondary collision with the wall of the pulverizing chamber.

According to the collision-type airflow pulverizer of the present invention having the above-described configuration, it is possible to efficiently pulverize objects to be pulverized down to the order of several micrometers by using 5 high-speed airflows. In particular, objects made of thermoplastic resin or objects whose main component is a thermoplastic resin can be efficiently pulverized to the order of several μm.

Further, the present invention will be explained in detail based on the accompanying drawings. FIG. 1 is a diagram showing a schematic cross-sectional view of the impingement-type air current pulverizer of the present invention and an example of a flowchart of a pulverization method that combines a pulverization process using the pulverizer and a classification process using a classifier. The powder raw material 15 to be pulverized is obtained by dispersing the powder raw material through a plurality of powder raw material supply ports 1 provided upstream of the acceleration tube 2 shown in FIG. It is supplied to the acceleration tube 2. Compressed gas such as compressed air is introduced into the acceleration tube 2 from a compressed gas supply nozzle 3, and the powder raw material 15 supplied to the acceleration tube 2 is instantly accelerated.
Will have high speed. The powder raw material 15 discharged from the acceleration tube outlet 4 into the crushing chamber 5 at high speed collides with the collision surface 7 of the collision member 6 and is crushed. In addition, in such a crusher, a secondary air introduction port 11 is provided between the powder raw material supply port 1 of the acceleration tube 2 and the acceleration tube outlet 4, and by introducing secondary air into the acceleration tube, the powder raw material The suction capacity of the supply port 1 is improved, the material to be crushed in the acceleration tube is dispersed, the material to be crushed is jetted out from the acceleration tube outlet 4 more uniformly, and the material to be crushed is efficiently (collided with) the collision surface 7 of the opposing collision member 6. This makes it possible to improve the pulverization performance compared to the conventional method.The secondary air introduced here contributes to loosening and dispersing the agglomeration of the material to be pulverized that moves at high speed in the acceleration tube. This has the effect of accelerating the flow along the inner wall of the accelerating tube, which is the part of the tube where the accelerated gas flow velocity distribution is slow.

FIG. 3 shows a sectional view of a main part of the accelerator tube, and will be explained in more detail. As a result of extensive studies regarding the method of introducing secondary air, the following conclusions were reached. That is,
Regarding the introduction position of the secondary air, in Fig. 3, the distance between the material supply port 1 and the acceleration tube 804 is X, and the distance between the material supply port 1 and the secondary air introduction port 11 is Y. ,X
and Y is 0, 2≦Y/X;0. 9 More preferably, good results were obtained when 0.3≦Y/X≦0.8 was satisfied. Furthermore, regarding the introduction angle of the secondary air inlet 11, where ψ is the angle with respect to the axial direction of the accelerator tube in FIG. Good pulverization results were obtained when the following conditions were satisfied. Regarding the volume of secondary air introduced, the volume of the carrier gas by the high pressure gas introduced from the compressed gas supply nozzle 3 was
Nm"/min, and when the total air volume of the secondary air introduced from the secondary air inlet 11 is bNm"/min, a, b
Good results were obtained when pulverization was carried out under conditions where 0.001≦b/a≦0.5, more preferably 0.01≦b/a≦0.4. As the secondary air, either compressed gas or normal pressure gas may be used. It is highly preferable to provide an air volume control device such as a valve at the secondary air inlet to adjust the introduced air volume. The position in the circumferential direction of the accelerator tube at which the disconnection port is to be provided may be determined as appropriate depending on the raw material to be crushed, the target size of the crushed particles, etc. FIG. 4 is a cross-sectional view taken along line BB in FIG. 3 in the case where eight secondary air inlets are provided in the diurnal direction of the accelerator tube as an example.

In this case, the distribution of secondary air introduced from the eight locations is appropriately set. Further, the cross section of the accelerator tube is not limited to a perfect circle.

On the other hand, in the crusher shown in FIG. 1, the collision surface 7 has an apex angle of 110
Since it has a conical shape with an angle of 180° or more, preferably around 160', the crushed material is dispersed substantially in the entire circumferential direction, causes secondary collision with the crushing chamber wall 8, and further Shattered. FIG. 2 is a diagram schematically showing a cross section of the collision type air flow crusher shown in FIG. It shows. From FIGS. 1 and 2, it can be seen that according to the collision type air flow crusher of the present invention, the secondary collision of the crushed materials on the crushing chamber wall 8 is effectively utilized. Furthermore, in the crusher of the present invention, as shown in FIG. Since the concentration of the (to-be) pulverized material in the vicinity of the collision surface 7 does not become high, the processing efficiency of pulverization can be improved, and it is possible to favorably suppress the fusion of the (to-be) pulverized material on the collision surface 7. be.

The material to be crushed introduced into the crushing chamber 5 is crushed by a first collision on the collision surface 7, and then further crushed by a secondary collision on the crushing chamber wall 8, and in some cases, the crushed material is crushed. The material is further crushed by tertiary (and quaternary) collisions with the crushing chamber wall 8 and the side surface of the collision member 6 before being conveyed to the discharge port 9 . The pulverized material discharged from the outlet 9 is classified into fine powder and coarse powder by a classifier such as a fixed wall air classifier. The classified fine powder is taken out as a pulverized product. The classified coarse powder is fed into the powder raw material supply port 1 together with the newly introduced material to be crushed.

As another example, in Figures 6 and 7, there are two and four
A cross-sectional view (C-C section cross-section in FIG. 1) in which two powder raw material supply ports are provided is shown. Further, the cross section of the acceleration tube 2 is not limited to a circular shape.

On the other hand, the inner diameter of the acceleration tube outlet 4 is usually 10 to 100 mm, and preferably smaller than the diameter of the collision member 6.

The distance between the acceleration tube outlet 4 and the tip of the collision member 6 is preferably 0.3 to 3 times the diameter of the collision member 6. If it is less than 0.3 times, over-pulverization tends to occur, and if it exceeds 3 times, the grinding efficiency tends to decrease.

Incidentally, the crushing chamber 5 of the collision type air current crusher according to the present invention is not limited to the box shape shown in FIG. 1.

The technical concept of the present invention is to introduce the powder raw material 15 into a carrier airflow of high-pressure gas introduced from the compressed gas supply nozzle 3, apply pressure from the acceleration tube outlet 4, and collide with the opposing collision member 6.
In a collision-type air flow crusher that performs pulverization by colliding the powder raw material 15 against the collision surface 7 of This is based on the idea that the suction force of the mouth 1 may affect the grinding efficiency. That is, the powder raw material 15 supplied from the acceleration tube 2 is delivered to the acceleration tube 2 in an agglomerated state.
As a result, the dispersion within the accelerating tube 2 becomes insufficient, and therefore, when ejected from the accelerating tube 804, the powder Ma degree varies, making it impossible to effectively utilize the collision surface 7. It was considered that the suction force of the powder raw material supply port 1 decreased, the supply of the powder raw material 15 became insufficient, and the pulverization efficiency decreased. This phenomenon becomes more noticeable as the amount of pulverization increases.

As the secondary air, either highly compressed gas or normal pressure gas may be used. It is highly preferable to attach an opening/closing device such as a valve to each secondary air inlet 11 to control the amount of air introduced. The number of secondary air inlets 11 to be installed and at which positions in the upper direction of the acceleration tube 2 may be appropriately set depending on the powder raw material 15, the target particle diameter, etc. FIG. 4 shows, as an example, a BB wedge sectional view in the case where eight secondary air inlets 11 are installed in the circumferential direction of the accelerator tube 2. In this case, the distribution of the secondary air to be introduced from the eight locations may be determined as appropriate.

As explained above, according to the apparatus and method of the present invention,
The powder raw material 15 can be distributed and supplied into the acceleration tube 2 from a plurality of powder raw material supply ports 1, and by introducing secondary air into the acceleration tube 2, the powder from the powder raw material supply port 1 can be distributed and supplied. The suction ability of the powder raw material 15 is improved, the powder raw material 15 is well dispersed in the accelerator tube 2, and the powder raw material 15 collides efficiently with the collision surface 17, thereby improving the pulverization efficiency. That is, the processing capacity is improved compared to conventional pulverizers, and the particle size of the resulting product can be made smaller with the same processing capacity.

In the conventional example, the powder raw material 15 is in an agglomerated state, and the collision surface 1
7.27, so fused materials are likely to occur, especially when the raw material is powder mainly composed of thermoplastic resin. In contrast, according to the present invention, the collision surface 7
Because it collides with the object, it creates a bond.

Further, in the conventional example, since the powder raw material 15 is agglomerated, over-pulverization tends to occur, and as a result, there is a problem that the resulting pulverized product has a wide particle size distribution. On the contrary,
According to the present invention, over-pulverization can be prevented and a pulverized product with a sharp particle size distribution can be obtained.

Further, according to the present invention, the powder raw material 15 can be distributed and supplied into the acceleration tube 2 from the plurality of powder raw material supply ports 1,
By introducing secondary air efficiently (introducing the powder raw material supply port 1
This improves the air suction capacity of the powder raw material unit 5, thereby improving the conveyance capacity of the powder raw material unit 5 within the acceleration tube 2, making it possible to increase the pulverization throughput compared to the conventional method.

The apparatus and method of the present invention have a smaller particle size (the effect becomes more pronounced).

[Examples] Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples.

The above raw materials were mixed in a Henschel mixer to obtain a mixture. Next, mix this mixture in an extruder to about 180%
After melt-kneading at a temperature of .degree. C., the mixture was cooled and solidified, and the cooled molten mixture was coarsely ground into particles of 100 to 1000 .mu.m using a hammer mill, which was used as powder raw material 15. And Figure 1~
Grinding was carried out using the grinder and flow shown in FIG. A fixed wall type wind classifier was used as a classification means to classify the pulverized powder into fine powder and coarse powder.

Here, in the collision type air flow crusher, the inner diameter of the outlet 4 of the acceleration tube 2 is 25 mm, satisfying the conditions shown in FIGS. 3 and 4, and the collision member 6 is made of aluminum oxide ceramic with a diameter of 60 mm. The collision surface 7 had a cylindrical shape, and the tip of the collision surface 7 had a conical shape with an apex angle of 160°. The central axis of the accelerating tube 2 and the tip of the collision member 6 coincided. The closest distance from the acceleration tube outlet 4 to the collision surface 7 was 60 mm, and the closest distance between the collision member 6 and the crushing chamber wall 8 was 18 mm.

The flow rate (a
)6.4Nm3/min (pressure 6.0kg/cm"
) is introduced, and 45 k is introduced from the powder raw material supply port 1.
Powder raw material 15 was fed at a rate of g/hour. The crushed powder raw material is transported to a classifier, the fine powder is removed as classified powder, and the coarse powder is returned to the powder raw material 15 from the powder raw material supply port 1.
It was also put into the accelerator tube 2. In addition, as secondary air,
0.1Nm”/min (5.0kg/c
m2) of compressed air (b) was introduced.As a result of this, a ground powder with a volume average particle size of 7.5 μm (measured by Coulter counter) was collected as fine powder at a rate of 45 kg/h. Further, even after continuous operation for 6 hours, no fused material was generated.

Although the particle size distribution of the toner can be measured by various methods, in this example, it was measured using a Coulter counter.

In other words, the measuring device is Coulter counter TA.
- An interface (manufactured by Nikkaki) that applies pressure to a number distribution of 1 volume using a type II (manufactured by Coulter) and a CX-
1 A personal computer (manufactured by Canon) is connected, and a 1% NaCj2 aqueous solution is prepared using primary sodium chloride as the electrolyte.

As a measuring method, 0.1 to 5 mj2 of a surfactant, preferably an alkylbenzene sulfonate, as a dispersant is added to the electrolytic aqueous solution at 100 to 150 mA, and 2 to 20 mg of a measurement sample is added. The electrolyte in which the sample was suspended was dispersed for about 1 to 3 minutes using an ultrasonic disperser, and the aperture was set to 100μ using the Coulter Counter TA-■ model.
m aperture, 2 to 40 μm based on the number of pieces
The particle size distribution of the particles was measured, and the values according to this example were determined from the particle size distribution.

The powder raw material used in Ki Tamu Yu Example 1 was
5mm, and in Figures 3 and 4, the following conditions are satisfied, and the collision surface of the collision member has an apex angle of 120mm.
Using an impingement type air flow crusher that has a conical shape with a
6.4 Nm”/min from compressed gas supply nozzle 3 (
Compressed air of 6 kgf/cm") was introduced, and the secondary air was F and G in Fig. 4.

0.0 each from 8 locations: H, I, J, N, L, M. lN
Compressed air of m3/min (5 kgf/cm2) was introduced, and 36 kg was supplied from powder raw material supply port 1 shown in Fig.
Powder raw material 15 was supplied at a rate of /hour. The pulverized powder raw material was conveyed to a classifier, the fine powder was removed as classified powder, and the coarse powder was again fed into the acceleration tube 2 together with the powder raw material 15 from the powder raw material supply port 1.

As a result, a pulverized powder with a volume average particle diameter of 7.5 μm (measured by Coulter counter) was obtained as a fine powder with a particle size of 36 k
g/hour. Further, even after continuous operation for 6 hours, no fused material was generated.

Tenjo 1 Gai 1 The powder raw material used in Example 1 was
5mm, and in Figures 3 and 4, the following conditions are satisfied, and the collision surface of the collision member has an apex angle of 120mm.
Using an impingement type air flow crusher that has a conical shape with a
6.4N m”/m from compressed gas supply nozzle 3
In (6kg f/cm'') of compressed air was introduced, and the secondary air was F and G in FIG.

0.1Nm each from 8 locations: H, I, J, N, L, M.
/min (5 kgf/cm") of compressed air was introduced, and 39.5 kg was
Powder raw material 15 was supplied at a rate of /hour. The pulverized powder raw material was conveyed to a classifier, the fine powder was removed as classified powder, and the coarse powder was again fed into the acceleration tube 2 together with the powder raw material 15 from the powder raw material supply port 1.

As a result, the pulverized powder with a volume average particle diameter of 7.5 μm (measured by Coulter counter) was 39.5 k
g/hour. Further, even after 6 hours of continuous operation, no fused material was generated.

Calibration The powder raw material used in Example 1 was pulverized with a conventional impingement air flow pulverizer shown in FIG. In this crusher, the collision surface 17 at the tip of the collision member 6 is a plane perpendicular to the axial direction of the acceleration tube 12, and the inner diameter of the joint tube outlet 4 is 25 mm. The acceleration tube 12 includes compressed gas supply nozzles 3 to 6.
4Nm”/min (6kg f/cm
The compressed gas of 2) was supplied, and the classifier was set to perform pulverization so that the fine powder (pulverized product) had a weight average particle size of 7.5 μm. The (to be) crushed material that collided with the collision surface 17 is transferred to the acceleration tube 12
Because the material is reflected in the direction opposite to the direction of the discharge port, the concentration of the material to be crushed near the collision surface is extremely high.Therefore, the feed rate of the raw material for the material to be crushed is 4.5 kg/hour. If this exceeds the limit, fusion and agglomerates begin to form on the collision member, and the fused substances sometimes clog the grinding chamber and classifier.Therefore, it is recommended to reduce the grinding throughput to 4.5 kg per hour. This was the limit of its crushing ability.

In addition, when pulverization is performed to obtain fine powder (pulverized product) with a weight average particle size of 11 μm, if the feed rate of the raw material to be pulverized exceeds 9 kg/hour, fusion and agglomerates will occur on the collision member. This began to occur and this became the limit of crushing capacity.

The powder raw material used in Example 1 was pulverized in the same manner as in Comparative Example 1 using the collision type air flow pulverizer shown in FIG. This pulverizer is completely the same as the pulverizer used in Comparative Example 1, except that the collision surface 27 at the tip of the collision member 6 is a plane inclined at 45° with respect to the axial direction of the acceleration tube 12. It's the same.

Compared to Comparative Example 1, the pulverized material that collided with the collision surface 27 was reflected in the direction away from the opening 4 of the acceleration tube 8, so that no fusion or agglomeration occurred. However, since the impact force is weak during collision, the crushing efficiency is poor and the weight average particle size is 7.
5μm fine powder (pulverized product) is approximately 4.5Kg per hour.
I couldn't get L.

Further, when obtaining fine powder (pulverized product) with a weight average particle size of 11 μm, only about 9 kgL could be obtained per hour.

Table 1 shows the results of the above examples and comparative examples.

Table 1 [Effects of the Invention] As described above, according to the collision type air flow crusher and crushing method of the present invention, it is possible to prevent fusion and generation of aggregates during crushing, and to enable stable operation of the device. . Moreover, since the pulverized material has a strong secondary collision with the wall of the pulverizing chamber, the pulverizing ability of the conventional method can be significantly improved.

With the above, it is possible to improve the pulverization efficiency, that is, the productivity.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a schematic cross-sectional view of an impingement-type air flow crusher of the present invention and a flowchart of a crushing method using a combination of the crusher and a classifier. FIG. 2 is a sectional view taken along the line AA in FIG. 1, showing the inside of the crushing chamber. FIG. 3 is a diagram showing the main parts of the accelerator tube. FIG. 4 is a sectional view taken along line BB in FIG. 3, showing an example of the arrangement of the secondary air inlet. 5, 6, and 7 are diagrams showing specific examples of cross sections taken along the C-0 plane of FIG. 1. FIGS. 8 and 9 are diagrams showing a schematic cross-sectional view of a conventional collision-type air flow crusher and a flowchart of a crushing method.

Claims (1)

[Scope of Claims] (1) A collision member for crushing the powder raw material ejected from the acceleration tube by collision force is installed downstream of the acceleration tube for transporting and accelerating the powder raw material by high-pressure gas at the acceleration tube outlet. In a collision type airflow crusher having a crushing chamber disposed facing each other, the acceleration tube is provided with a plurality of powder raw material supply ports, and secondary air is introduced between the plurality of powder raw material supply ports and the acceleration tube outlet. a mouth is provided, and the tip portion of the collision surface of the collision member has an apex angle of 11.
A collision type air flow crusher characterized by having a conical shape with an angle of 0° or more and less than 180°. (2) If the distance between the plurality of powder raw material supply ports provided in the acceleration tube and the acceleration tube outlet is X, and the distance between the plurality of powder raw material supply ports and the secondary air introduction port is Y, then The impingement type air flow crusher according to claim 1, wherein and Y satisfy 0.2≦Y/X≦0.9. (3) The introduction angle Ψ of the secondary air inlet provided in the acceleration tube satisfies 10°≦Ψ≦80° with respect to the axial direction of the acceleration tube. Collision type air flow crusher. (4) The powder raw material is conveyed and accelerated by high-pressure gas in the acceleration tube provided in the collision type air flow crusher according to any one of claims 1 to 3, and is discharged from the acceleration tube outlet into the crushing chamber, and the opposing collision member In the pulverization method of pulverizing the powder raw material into fine particles by colliding with the powder raw material, the powder raw material is guided upstream of the acceleration tube from a plurality of powder raw material supply ports, and the powder raw material is guided between the plural powder raw material supply ports and the acceleration tube outlet. The powder raw material is crushed by colliding with a colliding member having a conical shape in which the tip of the colliding surface has an apex angle of 110° or more and less than 180°, and the crushed material after the collision is further crushed. A grinding method characterized by grinding by secondary collision with the wall of a grinding chamber. (5) When the air volume of high-pressure gas that conveys and accelerates the powder raw material introduced into the acceleration tube is aNm^3/min, and the air volume of secondary air is bNm^3/min, a and b are 0.001≦ Claim 4, characterized in that the pulverization is carried out under conditions satisfying b/a≦0.5.
Grinding method as described.