JPH07289933A - Grinder - Google Patents

Abstract

PURPOSE:To enhance the grinding efficiency by effectively utilizing a grinding energy by forming the collision surface of the collision member arranged in front of the ejecting direction of compressed air and opposed to a grinding nozzle from a protruding central part and an outer peripheral collision surface. CONSTITUTION:In a grinder, compressed air is ejected to the raw material to be ground introduced into a fluidized bed grinding chamber from a grinding nozzle 5 to finely grind the raw material to be ground. A collision member 9 is arranged in front of the ejecting direction of compressed air in opposed relation to the grinding nozzle 5. In this case, the collision surface of the collision member 9 is formed from a protruding central part 11 and an outer peripheral collision surface 12. When the vertical angle of the protruding central part 11 is set to alpha and the angle of inclination to the vertical surface of the center axis in the grinding nozzle 5 of the outer peripheral collision surface 12 is set to beta deg., these angles alpha deg., beta deg. satisfy O<alpha<90, beta<>O and 30<=alpha+2beta<=90. By this constitution, a grinding energy is effectively utilized to enhance the grinding efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for improving a fluidized bed type jet mill or a swirling flow type jet mill using a jet stream.

[0002]

2. Description of the Related Art In a fluidized bed type jet mill, generally, compressed air is jetted from a pulverizing nozzle, and the energy of a high-speed air flow causes particles to collide with each other to pulverize an object to be pulverized, and thereafter, if necessary. The particles crushed by a classifier are classified to obtain particles having a desired crushed particle size. Further, a swirling flow type jet mill generally has a swirling crushing chamber, and compressed air is jetted from the crushing nozzle into the swirling crushing chamber, and the energy of the high-speed swirling air flow causes particles to collide with each other and to be covered. The pulverized product is pulverized, and then the particles pulverized by a classifier are classified as necessary to obtain particles having a desired pulverized particle size.

The advantage of these jet mills is that the injection of compressed air from a nozzle is used, and a temperature drop occurs due to the adiabatic expansion action, so that substances that dislike heat can be pulverized. Since collision of the particles, that is, surface pulverization is the main, it is suitable for fine pulverization.
On the contrary, as a disadvantage, since a large amount of compressed air is used, a large compressor is required, the energy consumption for pulverization is large, and further, the collision of particles is mainly, so that ultrafine powder is easily generated, Further, there is a problem that particles having a small number of collisions are discharged as coarse powder, and the crushed particle size becomes coarse. Especially when compared with so-called collision type jet mill,
There is also a problem that the energy consumption in the pulverization is large and the efficiency is remarkably lowered when finer particles are obtained.

A crushing device which solves the above problems has been proposed in Japanese Patent Laid-Open Nos. 3-213356 and 3-213161. That is, JP-A-3-21356 proposes to reduce energy consumption by using a collision member having a specific shape, particularly a spherical collision member, in a swirling flow type jet mill. In addition, JP-A-3-21
In 3161, it is proposed to reduce energy consumption by using a collision member similar to the above, that is, a spherical collision member, in a fluidized bed jet mill. However, although the conventional problems are considerably improved by the above configuration, when the collision surface of the collision member is spherical, the impact force between the particles and the collision member is weakened on the collision surface, so compressed air is used. It was hard to say that they are still fully utilizing energy. That is, as described above, although various improvements have been made to the crushing device from the past, it is still not sufficient, and therefore, the advent of a crushing device having further excellent crushing energy efficiency is desired.

[0005]

Therefore, the object of the present invention is to solve the problems of the prior art as described above, to further improve the energy efficiency of pulverization, and to pulverize the pulverized raw material more efficiently. To provide a simple crushing device.

[0006]

The above objects can be achieved by the present invention described below. That is, the present invention is a fluidized bed type jet mill or a swirling flow type jet mill that pulverizes solid matter by injecting compressed air from a plurality of pulverizing nozzles in a pulverizing chamber, and the blast air in the forward direction of the compressed air is In a crushing device in which a collision member is provided at a collision position so as to face each crushing nozzle, the collision surface of the collision member has a projecting central portion having a projecting shape, and an outer circumference provided around the projecting central portion. It is a crushing device characterized by comprising a collision surface.

[0007]

As a result of intensive studies to solve the above-mentioned problems of the prior art, the inventors of the present invention have installed a collision member in a conventional crusher so that the injection air may collide forward in the injection direction, and the collision may occur. If the shape of the member is made specific, the number of collisions of the pulverized raw material is increased, and the pulverized raw material can be more effectively collided with the collision member. The present invention has been accomplished by finding that the above can be efficiently obtained.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to preferred embodiments of the present invention. The crushing apparatus according to the present invention is a fluidized bed type jet mill or a swirling flow type jet mill that crushes solid matter by injecting compressed air from a plurality of crushing nozzles in a crushing chamber, and injects compressed air forward in the injection direction. In a crushing device in which a collision member is provided at a position where air collides with each crushing nozzle, the collision surface of the collision member is provided in a protruding central portion of a protruding shape and around the protruding central portion. It is characterized by comprising an outer peripheral collision surface.

FIG. 1 is a schematic sectional view of an example of a fluidized bed type jet mill constituting a crushing apparatus according to the present invention,
FIG. 2 is a sectional view taken along the line AA ′ of FIG. In the figure, 1 is a fluidized bed type jet mill main body, 2 is a raw material supply device, 3 is a raw material supply screw feeder, 4 is a supporting member for supporting a collision member, 5 is a pulverizing nozzle, 6 is a compressed air inlet, and 7 is a flow. A layer crushing chamber, 8 is a classification rotor, 9 is a collision member, and 10 is a discharge pipe.

In the above-mentioned crushing device, the crushing raw material is introduced from the raw material supplying device 2 into the lower part of the fluidized bed pulverizing chamber 7 by the raw material supplying screw feeder 3, and the compressed air is jetted into the pulverizing chamber 7 from the pulverizing nozzle 5. The pulverized raw material is finely pulverized. The pulverized product thus pulverized is classified by a classification rotor 8 provided in the upper part of the fluidized bed pulverization chamber 7, and the pulverized product having a desired particle size distribution is discharged from the discharge pipe 10. In the present invention, as shown in FIG. 2, a collision member having a specific shape is provided at a position in front of the crushing nozzle 5 in which the blast air collides, so as to face each crushing nozzle. By providing such a collision member, it becomes possible to utilize the compressed air energy input to the fluidized bed pulverization chamber 7 more effectively in the pulverization process. This will be described below.

FIG. 3 is a partially enlarged sectional view of the collision member 9 and the crushing nozzle 5, which are the main components of the crushing device according to the present invention. As shown in FIG. 3, the collision member according to the present invention comprises a protruding central portion 11 and an outer peripheral collision surface 12.
The solid-gas mixture flow of the compressed air ejected from the crushing nozzle 5 and the crushing raw material supplied into the crushing chamber 7 is first of all the protruding central portion 11 of the collision member provided facing the crushing nozzle 5.
Is first crushed on the surface of the
After being secondary pulverized in, the particles are further pulverized by collision of particles in the fluidized bed pulverization chamber 7.

At this time, when the collision surface of the collision member has a specific shape, the primary crushing and the secondary crushing are performed more efficiently. That is, the apex angle α (°) of the protruding central portion 11 of the collision surface of the collision member and the outer peripheral collision surface 12 provided around the protruding central portion with respect to the plane perpendicular to the central axis of the crushing nozzle 5. When the inclination angle β (°) satisfies the relationship of the following formula, very efficient grinding is performed. 0 <α <90, β> 0 30 ≦ α + 2β ≦ 90

Considering the reason for this, first, the angle α
When ≧ 90, the reflected flow of the pulverized material that is primarily pulverized on the projection surface disturbs the flow of the solid-gas mixture flow, which is not preferable. When the angle β = 0, that is, when the outer peripheral collision surface is at a right angle to the solid-gas mixture flow, the reflected flow at the outer peripheral collision surface flows toward the solid-gas mixture flow, so that the solid-gas mixture flow is turbulent. Is not preferable. Further, when the angle β = 0, the powder concentration on the outer peripheral collision surface becomes large, and when the powder of the thermoplastic resin or the powder mainly containing the thermoplastic resin is used as the raw material, the melting on the outer peripheral collision surface occurs. Kimono and agglomerates are likely to be formed, and when such a fused material is formed, stable operation of the apparatus becomes difficult. Also, the angle α
And the angle β is in the relationship of α + 2β <30, the impact force of the primary pulverization on the surface of the protrusions is weakened, resulting in a reduction in pulverization efficiency, which is not preferable. On the other hand, the angles α and β are α + 2β>
In the case of the relationship of 90, the impact force of the secondary crushing on the outer peripheral collision surface is weakened, so that the crushing efficiency is lowered, which is not preferable.

As described above, when the angle α and the angle β satisfy the relationship of the following equation, 0 <α <90, β> 0 30 ≦ α + 2β ≦ 90 More preferably, the angle α and the angle β are as follows. When the relationship is satisfied, the crushing is efficiently performed, and the crushing efficiency can be improved. 10 <α <805 5 <β <40 That is, a collision member is installed facing each crushing nozzle at a position where the blast air in front of the crushing nozzle 5 collides, and the collision member has a specific shape. According to the crushing device of the present invention described above, the number of collisions of the crushing raw material can be significantly increased as compared with the conventional crushing device, and the crushing raw material can be more effectively collided.

FIG. 4 is a schematic sectional view of an embodiment of a swirl flow type jet mill constituting the crushing apparatus according to the present invention. Further, FIG. 5 shows a sectional view taken along the line BB ′ of FIG. In the figure,
21 is a swirling flow jet mill main body, 5 is a crushing nozzle, 9
Is a collision member, 22 is a compressed air chamber, and 23 is a swirling crushing chamber. In the swirling flow type jet mill, compressed air is injected into the swirling and crushing chamber 23 from the crushing nozzle 5, and the crushing raw material is crushed by the energy of the high-speed swirling air flow generated at that time. Mill body 21
In the swirling crushing chamber 23, a collision member having a specific shape is provided at a position in front of each crushing nozzle 5 in the injection direction so as to face each crushing nozzle. As a result, the input compressed air energy is more effectively utilized for pulverization.

The shape of the collision member provided in the above-mentioned swirling flow type jet mill also has the shape shown in FIG. 3, similarly to the case of the fluidized bed type jet mill described above. That is, as shown in FIG. 3, the collision member has a projecting central portion 11 and an outer peripheral collision surface 12, and the compressed air jetted from the crushing nozzle 5 in the direction in which a swirl flow is generated and the crushing supplied to the crushing chamber. The solid-gas mixture flow with the raw material is first pulverized on the surface of the protruding central portion 11 of the collision member, and then secondly pulverized on the outer peripheral collision surface 12, and then pulverized by further collision of particles in the swirling pulverization chamber 23. To be done.

At this time, the apex angle α (°) of the protruding central portion 11 projecting on the collision surface of the collision member and the inclination angle β (°) of the outer peripheral collision surface with respect to the vertical plane of the central axis of the crushing nozzle are as follows. When the relationship of the formula is satisfied, 0 <α <90, β> 0 30 ≦ α + 2β ≦ 90, and more preferably, when 10 <α <805 5 <β <40, the grinding is efficiently performed and the grinding efficiency is improved. It can be done. That is, also in the swirling flow type jet mill, as in the case of the fluidized bed type jet mill described above, a collision member is installed facing each pulverizing nozzle at a position where the blast air in front of the pulverizing nozzle 5 collides with the pulverizing nozzle. According to the crushing device of the present invention in which the collision member has a specific shape, the number of collisions on the collision member is increased,
In addition, more effective crushing can be performed.

In the crushing apparatus according to the present invention, it is preferable that the crushing nozzle 5 has a Laval shape, and the diameter of the outlet of the crushing nozzle 5 is smaller than the diameter of the collision member. Further, it is preferable that the tip end of the protruding central portion 11 protruding on the collision surface of each collision member and the central axis of the crushing nozzle 5 are substantially aligned with each other.

[0019]

EXAMPLES Next, the present invention will be described in more detail with reference to examples. An example of performing fine pulverization using the pulverizing apparatus of the present invention will be shown below. Example 1 In this example, the fluidized bed type jet mill shown in FIGS. 1 and 2 was used. The fine pulverization apparatus of this example was based on a counter jet mill 200AFG manufactured by Hosokawa Micron Co., Ltd., and a collision member having a specific shape was installed. As shown in FIG. 2, three Laval-shaped nozzles having an inner diameter of 4 mmφ are installed toward the center of the crushing chamber as the crushing nozzles provided in the circumferential portion of the crushing chamber, and these three crushing units are also used. Three collision members are installed facing the nozzles.
As the shape of the collision member, the apex angle α of the protrusion central portion is 50 °.
Of the conical shape, and the inclination angle β of the outer peripheral collision surface with respect to the vertical plane of the central axis of the crushing nozzle was 10 ° (α
+ 2β = 70 °).

As a pulverization raw material, a pulverized product of a toner material for electrostatic charge image development (1 mm screen pass product) is used, and finely pulverized using compressed air having a pulverization pressure of 6.0 kg / cm ² G, ³ Nm ³ / min. I went. The classifier used was 100ATP manufactured by Hosokawa Micron. 10 kg of crushed raw material
The toner was finely pulverized with a weight average particle diameter of 8 μm by introducing the mixture into the pulverizing apparatus having the above-described ratio at a rate of h and adjusting the rotation speed of the classifier. The particle size distribution of the obtained finely pulverized product can be measured by various methods. In the present invention, Coulter Multisizer II type (manufactured by Coulter Electronics Co.) is used, and an aperture of 100 μm is used.
Particle size distribution was determined using m-aperture.

Example 2 In this example, the swirling jet mill shown in FIGS. 4 and 5 was used. In the fine pulverizer of this example,
A crushing nozzle was provided on the circumference of the swirling flow crushing chamber, but as shown in FIG. 5, four Laval nozzles having an inner diameter of 4 mmφ were installed at an angle of 40 degrees offset from the center direction. Further, the crushing raw material was supplied from the upper part of the crushing chamber. As the shape of the collision member, the apex angle α of the central portion of the protrusion is 50 °, and the inclination angle β of the outer peripheral collision surface with respect to the vertical plane of the central axis of the crushing nozzle is 10 °, which is installed at a position facing each Laval nozzle ( α + 2
β = 70 °). The same raw material as in Example 1 was used as the raw material for pulverization, and fine pulverization was performed using compressed air at a pulverization pressure of 6.0 kg / cm ² , 4 Nm ³ / min. The classifier used was 100ATP manufactured by Hosokawa Micron. 1 crushed raw material
The weight average particle diameter is 7.8 μm by introducing into the crushing device having the above structure at a rate of 4 kg / h and adjusting the rotation speed of the classifier.
To obtain a finely pulverized product for toner.

Example 3 Using the fluidized bed jet mill shown in FIGS. 1 and 2, the same pulverization raw material as in Example 1 was used to perform fine pulverization under the same apparatus conditions. The pulverized raw material was introduced into the pulverizer at a rate of 6 kg / h, and the rotation number of the classifier was adjusted to obtain a finely pulverized product for toner having a weight average particle size of 6 μm.

Example 4 Using the swirling flow type jet mill shown in FIGS. 4 and 5, the same pulverization raw material as in Example 2 was used to perform fine pulverization under the same apparatus conditions. The crushed raw material was introduced into the crusher at a rate of 8 kg / h, the rotation speed of the classifier was adjusted, and the weight average particle diameter was 5.9 μm.
m finely pulverized product for toner was obtained.

Comparative Example 1 Fine pulverization was carried out under the same conditions as in Example 1 except that the collision member was not provided in the pulverization chamber, using the same pulverization raw material. As a result, in the fluidized bed type jet mill having the structure in which the collision member is not provided, the same crushing pressure of 6.0 kg / c as in Example 1 was used.
By fine pulverization using compressed air of m ² G, ³ Nm ³ / min, a finely pulverized product of 8 μm was obtained at a pulverized raw material supply rate of 3 kg / h.

Comparative Example 2 Fine pulverization was carried out under the same conditions as in Example 2 except that the collision member was not provided in the pulverization chamber, using the same pulverization raw material. As a result, in the swirling flow type jet mill having no collision member, the same crushing pressure of 6.0 kg / c as in Example 2 was used.
By fine pulverization using compressed air of m ² G and 4 Nm ³ / min, a finely pulverized product of 8 μm was obtained at a feed rate of pulverizing raw material of 4 kg / h.

Comparative Example 3 The collision member of the crushing device used in Example 1 had a spherical shape, and the same crushing raw material as in Example 1 was used for fine crushing.
As a result, the same grinding pressure as in Example 1 6.0 kg / cm ²
By fine pulverization using G, ³ Nm ³ / min of compressed air, a finely pulverized product of 8 μm was obtained at a feed rate of pulverization raw material of 7 kg / h. Compared with the case of using the fluidized bed type jet mill of Comparative Example 1 in which the collision member is not provided, the crushing amount is improved, but the collision member having a specific shape as in Example 1 is used. The amount of pulverization processing was inferior as compared with the case of providing.

Comparative Example 4 The shape of the collision member of the crushing apparatus used in Example 2 was spherical, and the same crushing raw material as in Example 2 was used for fine crushing.
As a result, the same grinding pressure as in Example 1 6.0 kg / cm ²
By fine pulverization using compressed air of G, 4 Nm ³ / min, a finely pulverized product of 8 μm was obtained at a feed rate of the pulverization raw material of 10 kg / h. Comparing this with the case of using the fluidized bed type jet mill of Comparative Example 2 in which the collision member is not provided,
Although the amount of pulverization processing has been improved, the amount of pulverization processing was inferior as compared with the case where a collision member having a specific shape as in Example 2 was provided.

Comparative Example 5 The same pulverized raw material as in Example 3 was used, and the same apparatus as in Comparative Example 1 was used to adjust the number of revolutions of the classifier to obtain a pulverized product having a weight average particle size of 6 μm. I could not get it even if I reduced the supply.

Comparative Example 6 The same grinding raw material as in Example 4 was used, the rotation speed of the classifier was adjusted using the same apparatus as in Comparative Example 2, and the weight average particle diameter was 6 μm.
Although it was tried to obtain the pulverized product, it could not be obtained even if the raw material supply amount was reduced.

As described above, according to the present invention, by providing the fluidized bed type jet mill or the swirling flow type jet mill with the collision member having a specific shape, first, the solid-gas mixture flow is generated in the central portion of the protrusion of the collision member. Primary crushing, then secondary crushing at the outer peripheral collision surface provided around the protruding central part, and then further crushing by collision of particles in the fluidized bed crushing chamber or swirling crushing chamber, resulting in conventional identification As compared with an apparatus not provided with a shaped collision member, crushing energy is effectively used, crushing efficiency can be significantly improved, and fine crushed particles can be efficiently obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of a crushing apparatus of the present invention using a fluidized bed type jet mill.

FIG. 2 is a sectional view taken along the line A-A ′ in FIG.

FIG. 3 is a partially enlarged view of a cross section of a collision member and a crushing nozzle provided in the crushing device shown in FIG.

FIG. 4 is a schematic cross-sectional view showing an embodiment of a crushing apparatus of the present invention using a swirling flow type jet mill.

5 is a sectional view taken along line B-B ′ of FIG.

[Explanation of symbols]

 1: Fluidized bed type jet mill main body 2: Raw material supply device 3: Raw material supply screw feeder 4: Colliding member supporting member 5: Grinding nozzle 6: Compressed air inlet 7: Fluidized bed grinding chamber 8: Classification rotor 9: Collision Member 10: Discharge pipe 11: Projected central portion 12: Outer peripheral collision surface 21: Swirling flow type jet mill main body 22: Compressed air chamber 23: Swirl crushing chamber 24: Collision member support member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoko Goka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (2)

[Claims] 1. A fluidized bed type jet mill or a swirling flow type jet mill which pulverizes solid matter by blasting compressed air from a plurality of pulverizing nozzles in a pulverizing chamber. In a crushing device in which a collision member is provided at a position facing each crushing nozzle, the collision surface of the collision member has a projecting central portion having a projecting shape, and an outer circumferential collision provided around the projecting central portion. A crushing device characterized by comprising a surface and a surface. 2. When the apex angle of the protrusion central portion is α (°) and the inclination angle of the outer peripheral collision surface with respect to the vertical plane of the central axis of the crushing nozzle is β (°), the angles α and β are as follows. The crushing device according to claim 1, wherein the crushing device is configured so as to satisfy the relationships shown in the equations. 0 <α <90, β> 0 30 ≦ α + 2β ≦ 90