JPH04210255A - Pulverizer and crushing method - Google Patents

Abstract

PURPOSE:To crush powder with an impact force by providing a suction nozzle for introducing powder into a crushing chamber by jet air, accelerating and injecting the powder and a collision member arranged in the injecting direction of the nozzle in opposition to the nozzle and injecting the powder from the nozzle. CONSTITUTION:A material 8 to be crushed is supplied to a suction nozzle 3 by a material feeder from a material inlet 1 above the nozzle 3. Compressed air is supplied to the nozzle 3 from a compressor 12 through a supply nozzle 2, and the material 8 is material exceeding the speed of sound is injected into a crushing chamber 9 from the tip of the nozzle 3, collided with the face 10 of a collision member 4 and primarily crushed. The powder is circumferentially dispersed, collided with the wall surface 7 of the chamber 9 and secondarily crushed. The powder is repeatedly crushed primarily and secondarily. The powder discharged from a discharge pipe 6 is classified by a classifier 12 into coarse powder and fine powder. The coarse powder is returned to the material inlet 1, and the fine powder is used as the product. When a special material is used, the fine powder is further pulverized, classified and surface-reformed into a product. The energy for crushing is reduced in this way.

Description

[Detailed description of the invention]

[00011

[Industrial Field of Application] The present invention relates to a pulverizing apparatus and a pulverizing method that utilize jet air, and more particularly, to a pulverizing apparatus and a pulverizing method that improve the pulverizing energy efficiency. [o o O2] [Prior Art] Generally, pulverizers are broadly classified into mechanical pulverizers and jet pulverizers. Mechanical crushers include Turbo Mill (manufactured by Turbo Kogyo Co., Ltd.) and KTM (Kawasaki Heavy Industries Co., Ltd.).
(manufactured by Co., Ltd.), a grinding rotor is rotated at high speed, and fine grinding is performed by collision between the rotor and the particles and grinding of the particles. On the other hand, jet-type pulverizers, such as the micronizer type and jet miser type, perform fine pulverization by colliding particles with each other using the force of ultra-high-speed jet air flow. Each type has distinct advantages and disadvantages due to differences in the crushing mechanism. Mechanical pulverizers consume less energy than jet pulverizers, but they do have the problem of generating heat, and when pulverizing materials that are sensitive to heat (1), for example, when crushing toner, cosmetics, etc., it can cause thermal deterioration of the product or damage to the inside of the equipment. It could not be used because it would cause adhesion and fusion. On the other hand, a jet crusher can lower the temperature inside the device due to the adiabatic expansion effect of compressed air, and unlike a mechanical crusher, it does not generate heat because it does not have rotating parts. therefore,
Widely used for pulverizing heat-sensitive substances. However, since the jet crusher uses a large amount of compressed air, it must be accompanied by a large compressor, which has the problem of consuming a huge amount of energy. [0003] In order to improve the problems of jet-type crushers, the energy of jet air is used for both collisions between particles and collisions between particles and a collision plate, thereby improving the energy efficiency of crushing. A crushing device for this purpose was proposed. (Utility Model No. 51-100374, No. 51-100375
Furthermore, attempts have been made to improve the crushing energy efficiency by improving the shape of the collision plate of the crushing device. for example,
(1) When the collision plate collision surface is perpendicular to the jet air injection direction; (2) When the collision plate collision surface is inclined with respect to the jet air injection direction
374, Japanese Patent Application Laid-Open No. 51-100375), (3) When the collision plate collision surface is an uneven surface (Utility Model Application No. 56-64754, Japanese Patent Application Laid-Open No. 57-50556) (4) When the collision plate collision surface is an uneven surface , in the case of a conical shape (JP-A-1-254266 and JP-A-1-254266)
-68154). [0004] If the collision plate collision surface in (1) is vertical,
As shown in Figure 3, the jet air colliding with the collision plate creates back pressure on the collision surface, which becomes a repulsive force for the particles mixed in the jet air flow, increasing the concentration of particles and increasing the probability of collision between particles. is high, but the particles are slowed down by the back pressure, making it difficult to obtain the energy necessary for crushing. Further, if pulverization due to the collision between the particles and the collision plate is considered as primary pulverization, pulverization due to the collision between the particles and the wall surface of the pulverization chamber, that is, secondary pulverization does not occur much. [0005] In the case of slope (2), the crushing pressure is dispersed and lowered, and the particles collide efficiently with the collision plate, but the collision force becomes smaller, so the effect of -order crushing does not improve much. . However, since the air flows in the inclined direction, the secondary crushing effect in that direction is improved compared to the case (1). [0006] In the case of the uneven surface (3), the flow of jet air is disturbed, so the efficiency of pulverization is not improved as much as expected. [0007] In the case of the conical shape (4), air flows in the circumferential direction and the secondary crushing effect is improved, but as in (2), the crushing pressure is dispersed and reduced, so the -second crushing The impact force is small. [00081 As mentioned above, among jet-type crushers that have been improved in various ways as described above, there is still no one that surpasses the crushing energy efficiency of mechanical crushers, and there is still a crushing device and a crusher with good crushing energy efficiency. It is hoped that a pulverization method will emerge. [0009] Therefore, the present invention has been made with the aim of improving the above-mentioned drawbacks in the conventional technology. [00101] That is, an object of the present invention is to provide jet air with high crushing energy efficiency, which improves the primary crushing effect due to the collision between particles and a collision member, and the secondary crushing effect due to the collision between the particles and the wall surface of the crushing chamber. The object of the present invention is to provide a pulverizing device and a pulverizing method. [00111

[Means for Solving the Problems] The present inventors have discovered that the above object can be achieved by making the collision surface shape of the collision member in a pulverizing device using jet air into a spherical shape. , we have completed the present invention. [0012] The pulverizer of the present invention includes a suction nozzle that carries, accelerates, and injects powder by the force of jet air into a crushing chamber, and is arranged opposite to the suction nozzle in the jetting direction of the suction nozzle. The collision member is characterized in that the collision member has a spherical shape and the collision surface of the collision member has a spherical shape. [0013] Furthermore, the pulverization method of the present invention includes carrying in powder by a suction nozzle, accelerating it, and further injecting it, and colliding the powder against a collision member having a spherical collision surface to perform pulverization.
It is characterized by performing closed-circuit pulverization in which the powder after collision is transported to a classifier and the unpulverized material is returned to the suction nozzle. [00141] The present invention will be explained with reference to drawings corresponding to embodiments. FIG. 1 shows a schematic cross-sectional view of a pulverizer of the present invention and a flowchart of a closed circuit pulverizer method combining the pulverizer and a classifier. The pulverizing device of the present invention has a pulverizing chamber 9
The powder is brought in and accelerated by the power of jet air,
It includes a suction nozzle 3 for injecting water, a collision member 4, and a discharge pipe 6. The collision member is provided to face the injection direction of the suction nozzle, and the powder carried in and accelerated by the force of the jet air is transported from the suction nozzle 3 to
It is injected into the injection chamber, collides with the collision surface 10 of the collision member 4, and is pulverized. Since the collision surface of the collision member has a spherical shape, the powder is dispersed in the entire circumferential direction, collides with the crushing chamber wall surface 7, and is secondary crushed. The pulverized material discharged from the discharge pipe 6 is transported to a classifier, and the separated coarse powder is returned to the suction nozzle in a closed circuit to perform closed circuit pulverization. [0015] In the pulverizer of the present invention, jet air injected from the suction nozzle collides with the spherical collision surface of the collision member provided in front of the suction nozzle. The air flow and pressure at that time behave as shown in FIG. In addition,
In FIGS. 3(a) and (b), when the collision member is a flat plate, (C
) and (d) show the case where the collision member is spherical. [0016] When the pressure drag is positive, it acts as a repulsive force on the jet air and particles, and when it is negative, it acts as an attractive force. In the case of a flat plate, the entire body is under positive pressure (repulsive force), whereas in the case of a sphere, the range of θ=30 degrees (center angle 60 degrees) acts as negative pressure (attractive force). In the present invention, since the collision surface of the collision member has a spherical shape, the powder in the air collides efficiently in this zone (collision surface with a central angle of 60 degrees), and -order pulverization is performed. In addition, since the collision surface of the collision member is spherical, the powder is efficiently dispersed in the entire circumferential direction and collides with the wall surface of the crushing chamber.
Secondary pulverization is performed, and compressed air energy can be effectively utilized for pulverization. [0017]

[Embodiment] An embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a cross-sectional view of the pulverizing apparatus of the present invention and a schematic diagram of a closed circuit pulverizing process in combination with a classifier, and FIG. 2 is a sectional view taken along line A-B of the pulverizing apparatus shown in FIG. [00181 In the figure, 9 is a crushing chamber, in which a suction nozzle 3 is provided on one of the inner walls, and a discharge pipe 6 is provided above. A collision member 4 is supported by a collision member support portion 5 at a position opposite to the jetting direction of the suction) paper 3. One end of the suction nozzle 3 communicates with the pulverized raw material input port 1 that supplies the pulverized raw material 8, and a compressed air supply nozzle 2 is disposed near the pulverized raw material input port 1. Compressed air is supplied from the compressor 13 to the compressed air supply nozzle 2 . The surface of the collision member 4 facing the suction nozzle 3 forms a spherical collision surface 10 . In addition, 7 is a crushing chamber wall, 11 is a suction nozzle tip, and 12 is a rotary classifier. [0019] In the above-mentioned pulverizing device, the pulverized raw material 8 is supplied to the suction nozzle 3 from the pulverized raw material input port 1 above the suction nozzle 3 by the raw material supply device. In the suction nozzle 3,
Compressed air having a pressure of 3 to 10 kg/c+m2G is introduced from the compressor 12 through the compressed air supply nozzle 2, whereby the pulverized raw material 8 is instantly accelerated to a speed exceeding the speed of sound in the suction nozzle at the same time as it is introduced. The pulverized raw material exceeding the speed of sound is discharged from the tip of the suction nozzle 3.
It is injected into the crushing chamber 9, collides with the collision surface 10 of the collision member 4, and is crushed. Since the collision surface of the collision member has a spherical shape, the powder is dispersed in the entire circumferential direction, collides with the crushing chamber wall surface 7, and is secondary crushed. The secondary pulverization and secondary pulverization are then repeated until the powder is conveyed to the discharge pipe 6. The powder discharged from the discharge pipe 6 is classified into coarse powder and fine powder by a classifier 12. The coarse powder side is again conveyed to the pulverized raw material input port 1, and the fine powder side is used as a product. Depending on the pulverized material used, the fine powder side is further subjected to treatments such as fine classification and surface modification before being turned into a product. [00201 In the present invention, the installation position of the collision member is
When the center direction of the jet air from the suction nozzle 3 is 0 degrees, it is most preferable that the center of the collision surface of the collision member is 0 degrees. If the center of the collision surface is extremely shifted from the center direction of the jet air from the suction nozzle 3, the jet air will not effectively hit the collision surface, resulting in a decrease in the efficiency of -order pulverization. For these reasons, there is no particular problem with the installation position of the collision member as long as it is near 0 degrees. Regarding the distance, when compressed air is injected from a nozzle, the zone where the injected compressed air has effective energy is called the potential core zone (usually a distance five times the inner diameter of the nozzle), but the collision surface of the collision member It is preferable that the distance between the tip and the suction nozzle tip 11 is 5 times or less, preferably 1 to 3 times the potential core zone. If the distance is more than 5 times, the particle velocity will be reduced and the grinding effect will be reduced. [00213 Also, the size of this collision member is preferably within a range that does not create resistance to the jet air, and the area of the plane or cross section perpendicular to the center direction of the jet air is equal to the minimum inner diameter of the suction nozzle. It is preferable that it is 50 times or less. [0022] Any wear-resistant material can be used for the collision member without any problem. Particularly desirable are wear-resistant alloys, wear-resistant surface-treated metals, and ceramics. Specifically, alloys include carbide, cobalt-based stellite alloy, nickel-based Deloro alloy, iron-based Delchrome alloy, tribaloy metal, and intermetallic compounds.
Ceramics include oxides such as alumina, titania, and zirconia, and carbides such as silicon carbide and chromium carbide. Examples include nitrides such as silicon nitride and titanium nitride, and borides such as chromium boride and titanium boride. [00231] Next, a specific example of pulverization using the pulverizer of the present invention will be shown. [0024] Example 1 A pulverizer shown in FIGS. 1 and 2 was used. This fine grinding device has a super hard collision member 4 with a diameter of 35 mmφ, a grinding chamber diameter of 100111 mφ,
The grinding chamber wall 7 was coated with alumina. The inner diameter of the compressed air supply nozzle is 9. 0mmφ, discharge pipe 6 has an inner diameter of 6
The collision member 4 was installed on the central axis of the ejected air at a position 65 mm from the suction nozzle tip 11, and the crushing was carried out under the conditions of a crushing pressure of 7°0 kg/Cm2G. [0025] As the pulverized raw material, a hammer mill crushed product of electrophotographic toner (weight average particle diameter D50 = 300 to 50
0 am), and the weight average particle diameter D50 (hereinafter simply referred to as D
50) was crushed under the above conditions to 9 μm and 7 μm, and the particle size distribution was checked using a coal tar counter TA-I.
I (manufactured by Coulter Electronics). The results are shown in Tables 1 and 2. [0026] Comparative Example 1 Pulverization was performed under the same conditions as in Example 1, except that the collision surface shape of the collision member was made perpendicular to the injection direction of jet air as shown in Figure 4b) so that D50 was 9 μm and 7 μm. I did it. The results are shown in Tables 1 and 2. [0027] Comparative Example 2 Except that the collision surface shape of the collision member was inclined at an angle of 45 degrees with respect to the injection direction of jet air as shown in FIG. 4c),
Grinding was performed under the same conditions as in Example 1 so that D50 was 9 μm and 7 μm. The results are shown in Tables 1 and 2. [0028] Comparative Example 3 The collision surface shape of the collision member was changed to an apex angle of 120 as shown in FIG. 4d).
D50 under the same conditions as Example 1 except that it was made into a conical shape.
Grinding was performed so that the diameters were 9 μm and 7 μm. The results are shown in Tables 1 and 2. [0029]

[Table 1]

[Table 2] [00301 As is clear from the results of the above Examples and Comparative Examples, by making the collision surface shape of the collision member in a pulverization device using jet air into a spherical shape, the collision between particles and the collision member can be improved. It can be seen that it is possible to increase the primary pulverization effect due to the collision between the particles and the wall surface of the pulverization chamber, and the secondary pulverization effect due to the collision between the particles and the wall surface of the pulverization chamber, thereby reducing the energy consumption of pulverization. Furthermore, it can be seen that a sharp pulverized product can be obtained in terms of particle size distribution. (00311Next, in order to select the material of the collision member,
In the pulverizer used in Example 1 and Comparative Examples 1 to 3, the collision member was made of carbide (material WH40, manufactured by Hitachi Metals, Ltd.), powdered high-speed tool steel (
HAP40, manufactured by Hitachi Metals, Ltd.), Sialon (HCN)
10, manufactured by Hitachi Metals, Ltd.), 5US304 for comparison
Using a hammer mill crushed product (200 to 500 μm) of a magnetic powder-containing resin as a raw material under the same conditions as in Example 1, pulverization was carried out for 4 hours at a raw material supply rate of 10 kg/hr. degree) was measured. The results are shown in Table 3. [0032]

[Table 3] [00331 As is clear from the above results, carbide is S
96.6 times that of US 304, 71.2 times that of HAP40,
For Sialon, it was 55.4 times higher, and good wear resistance was obtained in both cases. [00341] [Effects of the Invention] The pulverizing device of the present invention has a spherical collision surface shape of the collision member as described above, so that the primary pulverization effect due to the collision between the particles and the collision member and the separation between the particles and the crushing chamber can be achieved. It is possible to increase the secondary crushing effect due to collision with the wall surface and reduce the crushing energy consumption. Furthermore, a pulverized product with a sharp particle size distribution can be obtained. Furthermore, the wear-resistant material makes it possible to crush highly abrasive powders.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a pulverizing device of the present invention and a schematic view of a closed circuit pulverizing process combining a classifier.

FIG. 2 is a sectional view taken along line AB of the pulverizer in FIG. 1.

FIG. 3 is a diagram schematically showing the flow and pressure of air when jet air collides with the collision surface of the collision member.

FIG. 4 is a diagram schematically showing the shape of a collision surface of a collision member.

[Explanation of symbols]

1. pulverized raw material input port, 2. , , Compressed air supply nozzle, 3, , Suction nozzle, 4. , , Collision member, 5
．． , , collision member support section, 6. ,,,exhaust pipe,7. ,,
, grinding chamber wall, 8. ,,,pulverized raw material,9. , , Grinding chamber, 10. , , Collision surface, 11. ,,, Suction nozzle tip,
12. , , Rotary classifier, 13. ,,,compressor

[Figure 1]

Claims (2)

[Claims] 1. A grinding chamber includes a suction nozzle that carries, accelerates and injects powder by the force of jet air, and a collision member disposed opposite the suction nozzle in the jetting direction of the suction nozzle. A pulverizer which injects powder from a suction nozzle and pulverizes the powder by impact force, wherein the collision surface of the collision member has a spherical shape. [Claim 2] Powder is carried in by a suction nozzle, accelerated, and further injected, and the powder is pulverized by colliding with a collision member whose collision surface has a spherical shape, and the powder after collision is conveyed to a classifier. A pulverization method characterized by performing closed-circuit pulverization in which the unpulverized material is returned to a suction nozzle.