JPS6345266B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wind classifier, and more particularly, a granular material to be classified is introduced into a classification chamber having a vertical axis, and a classification blade is driven to rotate around the vertical axis in the upper part of the classification chamber. The present invention relates to a wind classifier which performs the classification function of powder and granular materials.

Conventionally, a wind classifier using a classification blade is equipped with a blade member whose height in the vertical direction is larger than the length in the radial direction, and a blade member whose height in the vertical direction is smaller than the length in the radial direction. A wind-powered classification device using a classification blade has been realized.

In the former conventional technique, the range of particle diameters after classification is theoretically narrow, and sharp classification is possible. However, the tangential velocity of the swirling airflow outside the classification blade is extremely small compared to the tangential velocity of the forced vortex flow inside the classification blade. Therefore, the centrifugal force necessary for the coarse particles classified by the classification blade to reach the side wall of the classification chamber and be separated cannot be obtained from the swirling airflow, and they return to the classification blade and mix with the fine particles. do. This phenomenon of coarse particles getting lost in fine particles is caused by
This becomes noticeable as the particle concentration in the airflow increases, so the classification efficiency significantly decreases in the classification treatment of high-concentration powder and granular materials.

On the other hand, in the latter conventional technique, since the strength of the centrifugal force differs at each position along the radial direction of the classification blade, theoretically the particle size range after classification is wide and sharp classification is impossible. However, a stronger centrifugal force acts on the particles subjected to the classification action due to the forced vortex generated by the classification blades extending to the vicinity of the inner wall of the classification chamber. Therefore, the classified coarse particles overcome the inward airflow and reach the walls of the separation chamber, where they are separated.
Therefore, the reversal phenomenon of the former prior art is prevented from occurring, and the deterioration of the classification performance of high-concentration powder and granular materials is suppressed as much as possible.

An object of the present invention is to solve the technical problems of the above-mentioned conventional techniques and to provide a wind classifier that enables sharp classification of highly concentrated powder and granular materials.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of the present invention. This wind classifier is a so-called separator for an air sweep mill, and includes a casing 2 forming a classification chamber 1 having a vertical axis, and a first classification blade 3 rotatable around the vertical axis within the classification chamber 1.
A second classification blade 4 rotatable around the vertical axis within the classification chamber 1, a drive means 5 for rotationally driving each classification blade 3, 4, and an outlet hole 6a concentrically connected to the top plate 2a of the casing 2. a discharge pipe 6 forming a
Inlet wind pipe 7 arranged concentrically at the bottom of the classification chamber 1
A coarse particle discharge chute 8 is connected to the lower end of the casing 2 at a distance from the outer periphery of the inlet wind pipe 7 to the outside, and a coarse particle discharge chute 8 is connected to the outlet hole 6a and is connected to the first and second classification blades 3 and 4. It includes, for example, four connecting wind pipes 9 extending outward in a tangential direction along the rotation direction, and a cyclone 10 connected to the outer end of each connecting wind pipe 9.

Gas containing the powder to be classified is introduced into the classification chamber 1 from the inlet wind pipe 7 upward as shown by the arrow 11. The gas introduced into the classification chamber 1 is
As shown by the dashed arrow 12, the air passes through the first and second classification blades 3 and 4, is led out in the tangential direction from the outlet hole 6a, and is led to the cyclone 10 through the connecting wind pipe 9. In the classification chamber 1, centrifugal force and force directed toward the center act on the granular material in the gas as described later, and the granular material is classified based on the difference between these forces.
The separated coarse particles descend along the inner wall of the casing 2 and are discharged from the discharge chute 8. Further, fine particles are collected by a cyclone 10. The clean gas from the cyclone 10 is drawn out via an outlet duct 13 by an induced blower 14.

The classification chamber 1 includes a cylindrical portion 16 and an inverted conical portion 17 that are concentrically connected. The outlet hole 6a is the cylindrical part 1
6, and the upper end of the discharge pipe 6 is connected to the end plate 1.
Blocked by 5. The drive means 5 includes a motor 18, a reducer 19 connected to the output shaft of the motor 18 and fixed to the end plate 15, and a drive shaft 20 connected to the output shaft of the reducer 19 and extending downward. The drive shaft 20 passes through the end plate 15 and enters the center of the classification chamber 1.

FIG. 2 is an enlarged sectional view of the vicinity of the first and second classification blades 3 and 4, and FIG. 3 is a sectional view taken along the section line - in FIG. A disc-shaped rotary plate 21 is fixed concentrically to the lower end of the drive shaft 20 . A plurality of first
A first classification blade 3 is configured by fixing the blade members 3a, and a second classification blade 4 is configured by fixing a second blade member 4a between the first blade members 3a or at the same position. be done.

The vertical height h1 of the first blade member 3a is selected to be larger than the radial length 1, and is 1/h1.
is selected to be, for example, 0.5 or less (1/h1≦0.5). Further, the outer diameter d1 of the first classification blade 3 is selected to be, for example, about 60 to 90% (d1/D≈0.6 to 0.9) of the inner diameter D of the cylindrical portion 16 in the classification chamber 1. The vertical height h2 of the second blade member 4a is selected to be smaller than the radial length 2, and 2/h2 is, for example, 2 to
It is selected to be around 5 (2/h2 = 2 to 5). Furthermore, the outer diameter d2 of the second classification blade 4 is larger than the outer diameter d1 of the first classification blade 3 (d2>d1), and is about 70 to 98% of the inner diameter D of the cylindrical portion 16 (d2/
D≒0.7~0.98).

The gas containing the powder to be classified rises in the inlet wind pipe 7 and is introduced into the classification chamber 1. In the classification chamber 1, the flow area of the gas increases as it ascends from the inlet wind pipe 7 to the inverted conical section 17 and further to the cylindrical section 16, thereby reducing the rate of rise of the gas. Therefore, relatively large coarse particles among the powder contained in the gas fall into the discharge chute 8 by gravity. Further, in the cylindrical portion 16, the direction of the rising gas flow is directed in the radial direction of the classification chamber 1 by the rotating plate 21 and an inverted conical deflection member 22 attached to the center of the lower surface of the rotating plate 21. turned outward. Therefore, among the powder and granules contained in the gas, medium coarse particles move outward in the radial direction of the classification chamber 1 due to inertia, collide with the cylindrical part 16, stall, and fall due to gravity. and is discharged from the discharge chute 8.

The gas reaching the upper part of the classification chamber 1 is first given a tangential velocity by the second classification blade 4. At the same time, since the outlet hole 6a has a smaller diameter than the cylindrical portion 16, a forced vortex flow toward the center is generated in the upper part of the classification chamber 1. Therefore, the powder and granular material in the gas is subjected to a centrifugal force and a force toward the center due to the forced vortex flow, and also a centrifugal force due to the collision with the second blade member 4a. Therefore, the coarse particles in the gas move outward in the radial direction of the classification chamber 1,
It descends along the inner surface of the cylindrical portion 16 and the inner surface of the inverted conical portion 17 and is discharged from the discharge chute 8 . Furthermore, the fine particles move toward the exit hole 6a due to the force directed toward the center.

As described above, the inward forced vortex generated by the second classification blade 4 is further enhanced by the rotational movement of the first classification blade 3. Therefore, the powder and granular material in the gas is subjected to a force directed toward the center due to the intensified inward forced vortex flow and a centrifugal force, as well as a centrifugal force due to the collision with the second blade member 4a. The force directed toward the center by this second classification blade 3 is
Since the airflow passes between the top plate 2a and the rotary plate 21 and flows toward the outlet hole 6a, its directionality is clear and its size is large compared to the second classification blade 4. Further, the centrifugal force due to the inward forced vortex flow is generated over a length of 1 along the radial direction of the first blade member 3a.
is small, so it is substantially uniform along the vertical direction of the first blade member 3a, that is, the direction perpendicular to the direction of the airflow. Therefore, in the first classification blade 3,
Particles in a gas have a clear directionality and are subjected to a classification action by a relatively large force directed toward the center and an even centrifugal force. Thereby, the coarse particles move radially outward of the classification chamber 1, descend along the inner wall of the classification chamber 1, and are discharged from the discharge chute 8, while the fine particles pass through the connecting air pipe 9 to the cyclone 10.
It is collected in

In this way, the powder and granules in the gas are first separated by the inward forced vortex flow by the second classification blade 4, and then
Furthermore, secondary separation is performed by an inward forced vortex flow by the first classification blade. Therefore, sharp classification of highly concentrated powder and granular materials can be achieved.

FIG. 4 is a sectional view of another embodiment of the present invention,
Parts corresponding to the embodiments of FIGS. 1 to 3 are given the same reference numerals. In the embodiments shown in FIGS. 1 to 3, the first blade member 3a and the second blade member 4a are fixed to the upper surface of the rotating plate 21. The first classification blade 3 is fixed to the upper surface of the second blade member 4.
A is fixed to the lower surface of the rotary plate 21 and the second classification blade 4
may be configured.

FIG. 5 is a sectional view of another embodiment of the present invention,
Parts corresponding to the respective embodiments described above are given the same reference numerals. In this embodiment, the first classification blade 23 is configured by fixing the first blade part 23a to the upper surface of the rotary plate 25. Further, the second classification blade 24 is configured by fixing the second blade member 24a to the upper surface of the rotary plate 26 disposed below the rotary plate 25. Moreover, the drive shaft 28 of the second classification blade 24 is inserted concentrically into the drive shaft 27 of the first classification blade 23, so that the first and second classification blades 23, 24 rotate around the same vertical axis. Driven.

As described in each of the above embodiments, the second classification blade may be disposed at the same height position as the first classification blade or at a position below the first classification blade.

Note that the number and mounting position of the first blade member and the second blade member to be attached are arbitrarily selected as long as an unbalance in rotational operation does not occur.

FIG. 6 is a longitudinal sectional view of a wind classifier according to another embodiment of the present invention. This wind classifier is a so-called cyclone air separator, and the casing 3
0 is constructed by disposing an inner cylinder 32 concentrically within an outer cylinder 31 having a vertical axis. A classification chamber 33 is formed in the inner cylinder 32, and an inlet chute 34 for the powder to be classified is concentrically inserted into the upper part of the classification chamber 33. A drive shaft 35 is disposed inside the inlet chute 34 and extends vertically, and the drive shaft 35 is rotationally driven by a motor 62 and a speed reducer 36 . Drive shaft 35 that has entered the classification chamber 33
A dispersion plate 37 is fixed concentrically to the lower end of the . A rotary plate 39 having a hole 38 corresponding to the opening of the lower end of the inlet chute 34 is disposed between the distribution plate 37 and the lower end of the inlet chute 34, and the rotary plate 39 is spaced apart in the circumferential direction. The dispersion plate 37 supports the dispersion plate 37 via a support plate 40 provided at the same time.

A first blade member 41a and a second blade member 42a are fixed to the outer peripheral edge of the rotary plate 39 in the same manner as in the embodiment shown in FIGS. A vane 42 is configured.

A plurality of connected wind pipes 43 are connected to the upper part of the inner cylinder 32 along the swirling direction of the vortex generated by the first and second classification vanes 41 and 42.
are connected to the cyclone 44, respectively. The outlet of each cyclone 44 is connected to the blower 4 via a duct 45.
6, and the outlet of the blower 46 is connected to the outer cylinder 31 via an introduction pipe 47. Therefore, gas, such as air, drawn from the cyclone 44 by the blower 46 is introduced into the casing 30 and is guided from the casing 30 to the cyclone 44 .

Note that a baffle 48 is provided in the middle of the inner cylinder 32, so that the air introduced into the outer cylinder 31 is introduced into the classification chamber 33 while being swirled by the buffle 48.

The powder and granules introduced from the inlet chute 34 fall onto the dispersion plate 37, and are dispersed into the air current that ascends while swirling inside the classification chamber 33 due to the centrifugal force exerted by the dispersion plate 37. At this time, coarse particles are separated and fall as they are, and are discharged from the discharge port 49. On the other hand, the powder contained in the airflow is further classified by the classification action of the first and second classification blades 41 and 42, and only fine particles are guided to the cyclone 44 and collected.

In this embodiment as well, as in the embodiments shown in FIGS. 1 to 3, sharp classification of highly concentrated powder and granular materials can be achieved.

FIG. 7 is a simplified longitudinal sectional view of a wind classifier according to another embodiment of the present invention. This wind classifier is a so-called vertical mill separator, and has a crushing mechanism inside the casing 50. That is, in the lower part of the casing 50, a crushing table 52 is provided which is rotationally driven around a vertical axis by a drive device 51, and a crushing roller 53 is provided which comes into contact with the upper surface of this crushing table 52 and is driven by the crushing table 52. It will be done. A plurality of, for example, four, crushing rollers 53 are arranged in the circumferential direction, and each crushing roller 53 is pressed against the upper surface of the crushing table 52 by a hydraulic cylinder 54 and a support arm 55. Therefore, the granular material placed on the crushing table 52 is crushed by being crushed between the crushing table 52 and the crushing roller 53.

A classification chamber 56 is formed above the crushing mechanism in the casing 50.
A rotating member 57 that is rotationally driven around a vertical axis is arranged on the upper part of the rotating member 6 . This rotating member 57 has an inverted conical support surface 58 that becomes smaller in diameter toward the bottom.
is formed, and a plurality of first
The first classification blade 59 is constructed by fixing the blade member 59a. The first blade member 59a is
The first classification blade 59 is inclined outwardly in the radial direction of the classification chamber 56 as it goes upward, so that the first classification blade 59 is formed into a cage shape as a whole. Such so-called squirrel-cage-shaped classification blades are conventionally known, and perform the same function as the first classification blade in each of the embodiments described above.

According to the present invention, a plurality of second blade members 60a are fixed to the lower part of the rotating member 57, thereby forming the second classification blade 60.

The powder and granules crushed by the crushing mechanism including the crushing table 52 and the crushing roller 53 are transported to the casing 50.
The classification chamber 56 is
rise within. The coarse particles in the airflow return and fall onto the crushing table 52, where they are subjected to the crushing action again. In addition, gas containing coarse particles that did not fall is
The first and second classification blades 59 and 60 receive the same classification effect as in each of the above-described embodiments. Therefore, the coarse particles are blown outward in the radial direction of the classification chamber 56 and fall onto the crushing table 52, and only the fine particles are led out from the outlet duct 61. Therefore, only fine particles with a narrow range of classified particle diameters can be obtained.

As described above, according to the present invention, the first classification blade performs the classification action after the second classification blade performs the classification action, thereby widening the adjustment range of the classified particle diameter. Moreover, the throughput per unit cross-sectional area of the classification chamber becomes large, and therefore the present apparatus can be made smaller. Furthermore, classification accuracy is improved.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is an enlarged sectional view of the vicinity of the first and second classification blades 3 and 4, and Fig. 3 is a view taken from the cutting plane line in Fig. 2. 4 is a cross-sectional view of another embodiment of the present invention, FIG. 5 is a cross-sectional view of another embodiment of the present invention, and FIG. 6 is a longitudinal cross-section of a wind classifier according to another embodiment of the present invention. FIG. 7 is a simplified sectional view of a wind classifier according to another embodiment of the present invention. 1, 33, 56... Classification room, 3, 23, 41, 5
9...First classification blade, 3a, 23a, 41a, 5
9a...First blade member, 4, 24, 42, 60...
...Second classification blade, 4a, 24a, 42a, 60a
...Second blade member.

Claims (1)

[Scope of Claims] 1. Powder to be classified is introduced into a classification chamber having a vertical axis, and a classifying blade that is rotated around the vertical axis in the upper part of the classification chamber performs the classification function of the powder and granule. In the wind classifier, a plurality of first blade members each having a height in the vertical direction larger than a length in the radial direction are arranged at intervals in the circumferential direction in the upper part of the classification chamber. A first classification blade is rotatably arranged around the vertical axis, and the height in the vertical direction is smaller than the length in the radial direction at the same height position as the first classification blade or below the first classification blade. A plurality of second blade members are arranged at intervals in the circumferential direction, and a second classification blade having a larger outer diameter than the first classification blade is rotatably arranged around the vertical axis; and the second
A wind classifier characterized in that the classification blades are driven to rotate in the same direction.