JPH0767541B2 - Horizontal swirl type jet mill - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal swirl flow jet mill for classifying powder having a coarse particle size into fine powder having a particle size of micron order while continuously classifying the powder.

2. Description of the Related Art Conventional jet mills of this type include, for example, JP-A-52-
There is one disclosed in Japanese Patent No. 4450, which is the fifth and sixth.
As shown in the figure, an outline thereof will be described.

The powder raw material is supplied from the hopper 41, and is jetted into the crushing chamber 43 at an angle α with respect to the radius of the crushing chamber 43 in the vicinity of the outer periphery of the crushing chamber 43, together with the high-pressure air jetted by the jet nozzle 42. On the other hand, high-pressure air is supplied from the air supply space 44 into an annular air chamber 45 formed on the outer periphery of the crushing chamber 43, and passes through a jet nozzle 47 arranged at an injection angle β on the annular wall 46 of the crushing chamber 43 to generate high pressure. Air is injected into the crushing chamber 43 to form a swirling air flow, the inside of which is a classification zone and the outside is a crushing zone.

Then, the raw material is supplied to the crushing zone as described above, and is crushed by collision of the raw materials accelerated at high speed in the swirling air flow. Then, this pulverized product is conveyed to the swirling air flow in the classification zone, the fine particles are carried along with the air flow and discharged from the product discharge pipe 48 to the outside, and coarse particles having a classification diameter or more are returned to the pulverization zone by the centrifugal force of the swirling air flow. The product that has been blown off and sucked into the jet stream of the next nozzle to be pulverized again, and the product that has been pulverized and classified again as described above is the product discharge pipe 48.
Will be discharged to the outside.

Problems to be Solved by the Invention In the conventional jet mill as described above,
The high-pressure air stream for pulverizing and classifying may be disturbed by the high-pressure air stream for supplying raw materials, and as a result of using this, the classifying action and the pulverizing action are difficult to be performed satisfactorily, resulting in insufficient pulverization Grain powder is crushing chamber 43 at the upper end of discharge pipe 48
There is a problem that it is difficult to prevent the weir pipe portion 49 protruding inward from being discharged and discharged to the outside.

An object of the present invention is to eliminate the problems brought about by the conventional jet mills described above, to perform pulverization efficiently, to perform classification reliably, and to efficiently produce a fine powder having a uniform particle size. To serve the mill.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention has an upper raw material supply port 3 and a lower product discharge port 4 which are substantially concentrically provided in the center of a crushing chamber 2 to supply the raw material. A rotary drive shaft 5 is vertically provided at the center of the mouth 3, and a rotor 6 is attached to the lower end of the drive shaft 5, and the rotor 6 and a dispersion plate 7 arranged horizontally near the raw material supply port 3 are provided. The dispersion plate 7 has a plurality of dispersion blades 8 and classification blades 9 which are respectively provided on the upper and lower surfaces of the dispersion plate 7 at the peripheral portions thereof, and the lower ends 12 of the classification blades 9 are inclined downward from the outer edge toward the inner edge. The weir pipe portion 11 at the upper end of the product discharge pipe 10 having the product discharge port 4 has an inverted conical shape so as to form a slight parallel gap with the lower end of the classification blade 9. It is a feature.

The raw material supply port 3 while rotating the rotor 6 by the drive shaft 5
While supplying the raw material into the crushing chamber 2 via the air supply pipe 14,
High-pressure air is injected into the crushing chamber 2 through the air supply chamber 15 and the air supply nozzle 16. The raw material thus supplied falls on the rotating dispersion plate 7, moves to the outer circumference by centrifugal force, and is dispersed toward the outer circumference in the upper part of the crushing chamber 2 by the dispersion blade 8. . Then, the particles thus dispersed are sucked into the air jet ejected from the air supply nozzle 16 and then accelerated to swirl at high speed in the grinding chamber, and the particles collide with each other to be ground. The particles crushed in this way are classified by the classifying blade 9, the finely divided product is taken out of the discharge pipe 10 through the classifying blade 9 along with the air flow, and the coarse particles are again centrifugally generated. It is blown toward the outer periphery and is crushed again in the same manner as described above.

Embodiment An embodiment of the present invention shown in FIGS. 1 to 3 will be described.

Reference numeral 1 denotes a casing, which is a top and bottom plate 19,2.
0 and the inner and outer annular side walls 21 and 22 separating them from each other. The inner side wall 21 forms the crushing chamber 2 and the side walls 21 and 22.
The air supply chambers 15 are formed respectively. And both side walls
21 and 22 each have an air supply nozzle similar to the conventional one.
6 and air supply pipe 14 are provided.

The raw material supply port 3 is provided substantially in the center of the top plate 19, and 30 indicates its center line. The drive shaft 5 is arranged so that its center is located on this center line 30, and its lower end is located in the crushing chamber 2. The rotor 6 is attached. The rotor 6 is a dispersion plate 7 arranged horizontally near the raw material supply port 3,
The dispersion plate 7 has a plurality of dispersion blades 8 and classification blades 9 which are respectively provided upright on the peripheral portions of the upper and lower surfaces of the dispersion plate 7. The lower ends 12 of the classification blades 9 are inclined downward from the outer edge toward the inner edge. . Although not shown, the classification blade 9 may be inclined with respect to the radial direction instead of being arranged in the radial direction as shown in FIG.

A motor 23 is provided on a support frame 24 provided on the top plate 19, and the drive shaft 5 is rotated by the motor 23 via pulleys 25, 26 and a belt 27. The rotation speed of the drive shaft 5 is adjusted by the specific gravity of the powder, the classification diameter of the particles, etc. Therefore, an inverter, a transmission or the like (not shown) is used.

In such a case, as described above, the supply port 3
While the raw material is supplied to the crushing chamber 2 in which the rotor 6 is rotating, a jet stream of high-pressure air is jetted from the air supply nozzle 16 and the raw material is blown toward the outer periphery of the crushing chamber 2 by the dispersion plate 7. Moreover, in the course of swirling along with the swirling flow of air, the products that collide with each other and are pulverized and become fine particles by the classifying blade 9 are taken out from the discharge port 4 to the outside.

At this time, even if relatively coarse particles fly to the vicinity of the classifying blade 9, due to the centrifugal force of the classifying blade 9 and the airflow flowing from the center to the outer periphery along both plates 19 and 20, the particles are crushed by the grinding chamber 2 Of the classification blade 9 and the upper end of the weir pipe portion 11 above the discharge pipe 10 to the discharge port 4. Even if there are coarse particles to be ejected, the gap between the two is a slight gap and is a parallel inclined surface. Therefore, due to the upward component force of the centrifugal force generated by the rotation of the lower end 12 of the classification blade 9, , The coarse particles are pushed upward along the inner peripheral surface of the weir pipe portion 11 and pushed back to the crushing chamber 2, and thus, the discharge of the coarse particles to the outside is effectively prevented.

FIG. 4 shows a product obtained by using the jet mill (A) according to the present invention and the conventional jet mill (B).
Shows the correlation between the raw material supply and the average particle size of the product,
(A) was for calcium carbonate, (b) was for thermoplastic compound, the air volume of the crushing air was 2.7 Nm ³ / min, and the pressure was 6.4 kg / cm ² . As is clear from these drawings, when the same amount of raw materials having the same particle size was supplied, the average particle size of the jet mill of the present invention was superior to that of the conventional jet mill. It is clear that

The number of blades 8 and 9 and nozzles 16 in the above embodiment is
Needless to say, it does not matter if it is not shown.

EFFECTS OF THE INVENTION The present invention is as described above, in which the upper raw material supply port, the lower product discharge port and the rotor are provided substantially concentrically in the crushing chamber, and the rotor is provided with a dispersion blade and a classification blade provided vertically. A plate is arranged, and the lower end of the classification blade and the weir pipe section at the upper end of the outlet are inclined with a slight parallel gap.The supplied raw materials are forcibly sent into the swirling airflow by the dispersion blades. In the classification blade, only the fine particles are discharged as a product by the air flow, and the coarse particles are forcibly returned to the swirling air flow, and the discharge port is still discharged. If you try to escape into the product, the classification blade and the weir pipe part will prevent the escape, so you can achieve good efficiency by rapid crushing of particles and ensure that coarse particles are not mixed into the product. You can stop Have an effect.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional front view of a part of the embodiment of the present invention in which the positions of the parts are shifted so that the structure of each part is clearly understood, and FIG. 2 is an enlarged view taken along line II-II of FIG. A sectional view, FIG. 3 is a sectional view taken along the line III-III in FIG.
FIGS. 4 (a) and (b) are graphs showing the correlation between the raw material supply amount and the product average particle diameter by the jet mill of the present invention and the conventional jet mill, and FIG. , A vertical sectional front view of the same as FIG. 1, FIG.
The drawing is a sectional view taken along line VI-VI in FIG. 1 ... Casing, 2 ... Grinding chamber 3 ... Raw material supply port, 4 ... Product discharge port 5 ... Drive shaft, 6 ... Rotor 7 ... Dispersion plate, 8 ... Dispersion blade 9 ... Classification blade, 10 …… Product discharge pipe 11 …… Weir pipe

Claims (1)

[Claims] 1. A pulverizing air is jetted into the pulverizing chamber from the periphery of a cylindrical pulverizing chamber formed in a casing, and a raw material is supplied from the upper portion of the pulverizing chamber to pulverize the raw material by the air. In a horizontal swirl type jet mill designed to discharge products, the raw material supply port on the upper side and the product discharge port on the lower side are provided substantially concentrically in the center of the grinding chamber, and the rotary drive shaft is located at the center of the raw material supply port. A disk-shaped rotor is attached to the lower end of this drive shaft, and the rotor is a horizontally arranged dispersion plate in the vicinity of the raw material supply port, and the periphery of the upper and lower surfaces of this dispersion plate. It has a plurality of dispersion blades and classification blades that are respectively installed upright, the lower end of the classification blade is inclined downward from the outer edge to the inner edge, and the weir pipe at the upper end of the product discharge pipe having the product discharge port. Part of the classification blade Horizontal swirling flow type jet mill, characterized in that has a inverted conical shape so as to form a small parallel gap between the end.