JP3154692B2 - Fine grinding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverizing apparatus for pulverizing a solid raw material into fine particles, and more particularly, to impact and shear by a blade or a liner while sending the solid raw material together with an airflow in the direction of a rotation axis, and to the mutual interaction of particles in the airflow. The present invention relates to a fine pulverizing apparatus for performing fine pulverization at room temperature by friction or crushing by high-frequency vibration.

[0002]

2. Description of the Related Art Among high-speed rotary mills, a so-called horizontal-shaft axial flow mill performs impact pulverization between a blade and a liner to create a high-speed vortex behind or at the edge of a high-speed rotating blade. Pulverization is performed by air vibration or the like. The pulverized raw material uniformly mixed with the air is accelerated in the cutting line direction of the rotor and then pulverized in each of the small chambers formed by the plurality of circular partition plates. Inside the pulverizing chamber, there is a high-speed air flow in the axial direction from the inlet to the discharge port.Each of the small chambers captures the particles in this air flow and performs the pulverizing operation. To prevent the coarsely pulverized particles from being discharged.

[0003] Conventional liners of a pulverizer include a liner having a large number of grooves in a direction intersecting the rotation direction of the blade and a liner having a fixed blade projecting parallel to the rotation axis. It was expected that a stronger impact force, shear force, and compression force would be expected.

Further, there has been a fine pulverizer which narrows the inner wall of a pulverizing chamber toward a product discharge port and expects a classifying action by a tapered blade opposed thereto. In this apparatus, the gap between the rotating blade and the inner wall is appropriately adjusted in accordance with the target particle size, and unregulated coarse particles are returned to the grinding chamber without being discharged.

[0005]

In recent years, in each of the industrial fields such as the inorganic chemical industry, the pharmaceutical and food industry, and the organic chemical industry, finer and more uniform fine powders more uniform than conventional powders have been developed. Has been requested. However, in order to obtain such fine particles using a conventional pulverizer, it is necessary to reduce the gap between the blade and the liner as much as possible and to increase the rotation speed. However, such an operation may induce heat generation of the pulverized raw material, and the efficiency cannot be denied.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the conventional fine pulverization apparatus as described above. It is an object of the present invention to provide a finely pulverizing device which can be obtained in a desired manner.

[0007]

In order to solve the above-mentioned problems, a fine pulverizing apparatus according to the present invention is provided on a product discharge port side of a pulverizing chamber with a side surface having a radius smaller than a rotation radius of a blade and substantially frustoconical. The grinding wheel is provided with a grinding surface, and a narrow classification gap is formed between the grinding wheel and a fixed grinding wheel having a grinding surface on a mortar-shaped inner surface.

[0008] Of the fine powder particles reaching the product discharge port side, those having a coarse particle size are located near the outer periphery of the blade due to centrifugal action, whereas those having a sufficiently fine particle size are light in weight due to the swirling airflow. And gradually gather toward the center of the rotation axis. The fine powder particles which have fallen to the vicinity of the classification gap in this way enter between the two grinding wheels by riding the high-speed airflow flowing through the gap. At this time, by adjusting the distance of the classification gap, the size of the fine particles that can be introduced into the gap can be limited. Further, the pulverized raw material that has entered between the two grindstones is made finer while colliding with the two grinding surfaces, and is conveyed to the discharge side.

Further, in the fine pulverizing device according to the second aspect, a grindstone-like grinding surface is provided on the outer end and the liner of the blade. For this reason, the pulverized raw material is not only subjected to the impact force and the shearing force by the blade and the liner, but also subjected to the grinding action, so that a finer product is produced.

By providing the grinding surface in the grinding chamber or in the classifying gap, finer and more uniform fine powder particles can be obtained without making the gap between the blade and the liner extremely close and without increasing the rotation speed. You can get the body.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of the pulverizer. The pulverizing apparatus 1 has a cylindrical pulverizing chamber 3 penetrating the rotating shaft 2 at the center, and a raw material supply port 4 at one end thereof.
A product outlet 5 is provided at the other end. A plurality of rotors 6 are attached to the horizontally supported rotating shaft 2, and a wing-like blade 7 is provided at the tip thereof. Grinding chamber 3 facing this blade 7
A liner 8 is mounted on the inner surface of the
A partition plate 9 is provided between them. In FIG. 1, the crushing chamber 3 is divided into three small chambers by two partition plates 9.

On the product discharge port 5 side of the crushing chamber 3, a rotating grindstone 10 having a radius smaller than the rotating radius of the blade 7 and having a substantially truncated cone shape is mounted, and a fixed grindstone having a mortar-shaped inner surface opposed thereto. 11 is protruded from the inner surface of the grinding chamber. Grinding surfaces are provided on opposing side surfaces of the two whetstones, and these gaps form a classification gap 12. On the raw material supply port 4 side of the pulverizing chamber 3, a coarse pulverizing unit 13 is provided for previously processing solid raw materials into coarse powder.

The rotary shaft 2 is supported by a casing 14 via a bearing 15. A pulley (not shown) is fixed to the shaft end of the rotary shaft 2, and rotational power is input from a motor via a belt.

The solid raw material supplied from the raw material supply port 4 is compressed and sheared at a peripheral speed lower than the rotational peripheral speed of the blade 7 in the pulverizing chamber 3 to be primarily crushed into coarse powder. A fixed blade 16 is provided on the liner 8 in parallel with the rotating shaft 2. Note that a cooling jacket (not shown) is provided on the outer periphery of the crushing chamber 3, and cooling water is circulated.

In the crushing chamber 3, the blade 7 for crushing is rotated at an extremely high speed by the driving of the rotating shaft 2, and spirally radially outward around the rotating shaft 2 by the inertial force and the centrifugal force in the rotating direction. Generates high-speed airflow. The coarse powder generated in the coarse crushing section 13 is sucked into the small chamber of the crushing chamber 3, and the coarse powder collides with each other while being accelerated radially outward by a high-speed airflow, or is hit by the blade 7, and is hit by the inner wall surface of the liner 8. Crash into. At this time, since the fixed blade 16 is protrudingly provided on the inner wall surface, when the coarse powder accelerated at a high speed repeats collision and repulsion, it receives a stronger impact force, shear force, and compression force to further promote the pulverization action. Therefore, the crushing efficiency is significantly improved.

Next, the structure and operation of the classifying section 17 will be described with reference to FIGS. The rotating grindstone 10 is a disk having a radius smaller than the rotating radius of the blade 7, and has a grinding surface 18 on a substantially frustoconical side surface whose diameter is reduced toward the product discharge port 5. The rotary grindstone 10 is desirably mounted on the rotary shaft 2 and is desirably provided with a radial deep feed groove 19 for feeding a solid material to the grinding surface 18. This greatly increases the feeding action, and the depth and arrangement of the feed grooves are appropriately adjusted depending on the solid material.

Similarly, it is desirable that the fixed grindstone 11 is also provided with a radial deep feed groove 21 on the grinding surface 20. Fixed whetstone 1
1 has an opening 11a in the center, and is detachably attached to a discharge port partition plate 22 also provided with an opening. By adjusting the distance between the classification gaps 12 of the two grinding wheels, the size of the fine particles that can be introduced into the gaps is limited. However, if the particle size is reduced, the processing capacity is reduced.
In order to pulverize efficiently, it is desirable to uniformly hold the powders and granules in each of the small chambers and sequentially feed them.

The grinding surfaces 18 and 20 of these grinding wheels are formed by electrodepositing, for example, diamond particles or cubic boron nitride (CBN), using silicon carbide or alumina ceramics, or using silicon carbide or An alumina-based vitrihide grindstone may be used.

The fine particles passing through the classification gap 12 are made finer while colliding with the grinding surfaces 18 and 20, and are conveyed to the discharge side. Such a grinding surface may be provided on the outer end of the blade 7 and the surface of the liner 8 as shown in FIG. 5. With this configuration, the raw material is subjected to impact force and shear force by the blade 7 and the liner 8. Not only that, but also the grinding action of the grinding surfaces 23 and 24, a finer product is produced.

In this embodiment, a liner having a fixed blade protruding in parallel with the rotation axis is used. However, a so-called groove type having a large number of grooves in a direction intersecting the rotation direction of the blade may be used. The shape of the blade and the number of rotors are also arbitrary. Further, the inclination of the classification gap in the classification section may be such that the radius of the truncated cone increases toward the product discharge port.

[0021]

As described above, the pulverizing apparatus according to the present invention has a grinding surface on the side of the product outlet of the grinding chamber, which has a radius smaller than the rotation radius of the blade and has a substantially frustoconical shape. A rotating grinding stone is provided, and a narrow classification gap is formed between the grinding wheel and the fixed grinding wheel, which has a grinding surface on the mortar-shaped inner surface. Since it is sent out while colliding with the surface, further miniaturization can be achieved.

In the fine pulverizing apparatus according to the second aspect of the present invention, since a grinding wheel-like grinding surface is provided at the outer end and the liner of the blade, the pulverized raw material is not only subjected to impact force and shear force by the blade and the liner, but is also subjected to grinding. Since it is also subjected to a crushing action, crushing is promoted. By providing a grinding surface in the crushing chamber and in the classifying gap in this way, it is possible to obtain a finer, more uniform, high-precision fine powder without narrowing the gap between the blade and the liner and without increasing the number of rotations. Obtainable.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pulverizing device.

FIG. 2 is an enlarged sectional view of a classification section.

FIG. 3 is a plan view of a rotary grindstone.

FIG. 4 is a plan view of a fixed grindstone.

FIG. 5 is a sectional view taken along line VV of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fine grinding apparatus 2 Rotating shaft 3 Grinding chamber 6 Rotor 7 Blade 8 Liner 10 Rotating grindstone 11 Fixed grindstone 12 Classification gap 17 Classification part

Claims (2)

(57) [Claims] A cylindrical pulverizing chamber having a raw material supply port at one end and a product discharge port at the other end and penetrating a rotary shaft at the center, and a plurality of rotary members protruding from the rotary shaft and having blades at a tip end. And a partition plate provided between adjacent rotors, and a fine crushing apparatus having a liner on the inner surface of the crushing chamber and facing the outer end of the blade, wherein a turning radius of the blade is provided on a product discharge side of the crushing chamber. It is characterized by forming a narrow classification gap between a fixed whetstone providing a grinding surface on a mortar-shaped inner surface and a rotating whetstone having a grinding surface with a smaller radius and a substantially frustoconical side surface. Crushing equipment. 2. The grinding device according to claim 1, wherein the blade has a grinding wheel-shaped grinding surface at an outer end thereof, and the liner has a grinding wheel-shaped grinding surface opposed to the blade grinding surface. A pulverizing device for forming a surface.