JPS59213476A - Powder classifier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powder classifier that uses wind power, and more specifically, the present invention relates to a powder classifier that uses wind power, and more specifically, a balance between the centrifugal force on particles due to the rotation of a classification rotor and the drag force due to air flow in the opposite direction to the classifier. This paper relates to a balanced type classifier that utilizes.

Conventionally, a centrifugal classifier that utilizes the rotation of a rotor is known as one of the wind classifiers, which is particularly effective in classifying relatively small particles (for example, several micrometers to 1,000 micrometers). .

This A11-1'! To do this, radial passages are formed in the body of a rotating classification rotor (hereinafter simply referred to as rotor), and air flows through these passages inward in the radial direction of the rotor, so that when the rotor is rotated at high speed, Balancing the centrifugal force acting on the powder supplied 17 into the passage and the conveying force acting on the powder particles by the air flow flowing radially inward,
Coarse powder with a large particle size mixed in the powder is moved to the outside in the rotor radial direction by the action of centrifugal force,
On the other hand, for fine powder with a small particle size, the conveying force of the airflow moves it upward and radially inward of the rotor, and the radial passage portion constitutes a classification chamber.

Then, regarding the two fine particles of the classified vehicle powder, the former coarse powder is flowed out by centrifugal force from the opening of the classification chamber on the outer periphery of the rotor into a circular path provided so as to surround the outer periphery of the rotor. The coarse powder is taken out of the classifier using a rotary valve, etc., which is a collection device, through the coarse powder guide pipe connected to the
On the other hand, the latter fine powder is usually taken out by a collection device such as a Zyclone or a pack filter through a suitable guide tube or the like.

By the way, in this yuzu classifier, it is important that the 7'L of powder supplied to the classification chamber is sufficiently dispersed in the airflow. If the powder contains water or the powder itself is adhesive, the powder may stick to walls etc. and interfere with the operation of the equipment. The importance of proper maintenance and inspection is also high. Therefore, the inventor of the present invention conducted repeated inspections on the application of the powder to the wall surface of the device, and found that
It has been found that this problem occurs particularly prominently on the upstream side of the coarse powder recovery device, that is, in the portion of the guide pipe leading from the main body of the classifier to the coarse powder recovery device. This is understood to be due to the fact that since the coarse powder recovery device generally operates in an air-sealed state for rotary pulp, etc., the flow of air at the coarse powder outlet becomes stagnant.

In addition, when classifying fine areas, this problem becomes even more pronounced when the rotor rotates at high speeds, which may lead to blockage of the pipe.

The present invention has been made in order to solve this problem, and it is possible to eliminate the problem without using other driving equipment such as attachment to a wall surface or vibration device for shaking off the il'T particles. The purpose of this system is to eliminate the buoy by releasing the pressure from the perspective of the connection relationship of the pipes at the point where the pipe system leading to the coarse powder recovery device becomes a kind of dead end and is in a positive pressure state. It is.

The aim of the present invention to achieve such an object is to have a classification chamber provided as a number of radial internal passages in the rotor, and to collect the dispersed powder f' supplied into the classification chamber. , a classification rotor that classifies and moves coarse powder to the outside in the radial direction of the rotor and fine powder to the opposite inner side by the action of rotor rotation and air flow, and an outer ring path facing the classification chamber opening on the outer periphery of this classification rotor. 7, and a coarse powder guide pipe connected to the coarse powder recovery device from a discharge opening provided in a part of the outer peripheral wall of the circular route. In the powder classifier, the coarse powder guide tube is bent from the control opening of the circular path outward in a substantially dogleg shape in the same plane as the circular path and returned to the circular path. The first pipe line connects to the first pipe line, and the second pipe line branches from near the deflection/curved part of this first pipe line and connects to the coarse powder recovery device ftLK (i). - Features of powder classifier.

According to such powder classification, in the first conduit connected in a roundabout manner to the circular path, the air flow containing coarse powder flows without stagnation, so that the particles are not stagnated. There is no stagnation of air that would promote adhesion to the pipe wall, and therefore particle adhesion πr is reduced even in the 81!2 pipe that is branched and connected to the first pipe. The problem of adhesion of powder particles is greatly improved and avoided), and in large classifiers, it can be used in place of the vibrating device described above or in combination with the vibrating device, and the addition of a vibrating device is short. Its usefulness is especially great for small classifiers.

Embodiments of the present invention will be described below with reference to the drawings while comparing them with conventional examples.

Figure 1 is a vertical sectional view showing an example of a classifier to which the present invention is applied, and Figure 2 shows the structure of a coarse powder guide tube made of unexploded pipes as cut 7hj on line A-A in Figure 1. Figure 3.
The figure shows a similar plane cross section of the conventional example, and Figure 4 is Japanese 3 Figure B-B #j! FIG.

First, let us briefly explain the outline of the classifier using Figure 1.
The device houses upper casings l and -F), 11 inside the casing 2, an integral classification rotor 4 and a balance rotor 5, which are rotated by a vertical rotating shaft j3;
A radial passage type classification chamber C is formed around the circumference of the classification rotor 4. In this example, the classification chamber C is in the form of a passageway with classification vanes 6 and 7 that also serve as inner and outer multiple radial partition walls, and its outer peripheral opening is formed by the upper casing l and is circular. It is open toward the ring road 8. Also, a circumferential gap hole 9 is provided on the soil side of the classification chamber C.
1. Powder introduced from the powder inlet 10 at the center of the upper part of the upper casing 1 is passed through the rotating radial dispersion vanes 11.11
．． ... It is moved radially outward while being rotated many times and enters the classification chamber C.

In addition, the upper surface of the classifying port to 4 is the dispersion blade 11°11,
... and the inner surface of the upper casing l, the dispersing blades 11.11.・
. . , and then secondary dispersion in the gap 12 between the inner surface of the upper casing 1 and the upper surface of the classification rotor 4, thereby achieving uniform powder dispersion.

In addition, the passage-type classification chamber C of the classification rotor 4 has a passage 111 formed in the balance rotor 5 with ll111 located downward on the inner blade side.
3, the outer circumferential portion of the balance rotor 5 is connected to the spiral case portion 14. This spiral case part 14 is connected to a collecting device such as a cyclone or a pack filter (not shown), and is also moved from the classification chamber C into the passage 13 by the suction action of the balance rotor 5 or by a blower (not shown) as shown by the arrow in the figure. It is arranged to produce an air flow of negative pressure shown.

In the figure, reference numeral 15 denotes an air introduction port into the annular passage 8 provided between the upper casing 1 and the lower casing 2, and 2n the incoming nitrogen air flow is connected to the lower end 7 run of the upper casing 1. and radial auxiliary blades 1 of the classification rotor 4
7.17. . . . so that only an inward flow is generated in the annular path 8. Also 18 is rotation +1'll
19 is a conical powder flow deflector mounted on the upper surface of the classification rotor 4 at a position below the powder inlet 10.

Due to the above-mentioned aging, when powder is continuously introduced through the powder inlet 10 while rotating at a predetermined speed, the introduced powder is transferred to the dispersion blade 11. II, by...
The particles are then dispersed, and then enter the classification chamber C through the gap hole 9.

In this classification chamber C, the powder is divided by the action of the centrifugal force exerted on the powder by the rotating classification blades 6 and 7, and the action of the drag force of the air flow caused by suction from the passage 13. Coarse powder with a large particle size in the body is subjected to a large centrifugal force and flows out to the circular path 8 on the outside of the diameter Q. On the other hand, fine powder with a small particle size is affected by a small centrifugal force and is therefore transported by the air flow. It will be sent into the spiral case part 14 through the storage passage 13,
This results in continuous powder classification.

Now, regarding one of the fine powders classified by the above classifier main body, as described in MfJ < iiG @ Ku 1 Part 14
A collection device MK such as a pack filter is sent and collected.
Therefore, for the other coarse powder, the coarse powder flow is discharged by centrifugal force into the circular path 8 facing the circumference of the classification rotor 4.
A portion of the outer circumferential wall of the annular passage 8 is provided so as to be guided to a coarse powder recovery device and recovered through a guide tube extending radially outward or tangentially.

FIGS. 3 and 4 show a conventional structure for such coarse powder recovery, in which an opening 20 provided in a part of the outer circumferential wall of the annular path 8 is connected to the approximately contacting edge of the classification rotor 4. A guide tube 21 extending in the direction is provided, and a tip opening 22 of the guide tube 21 is provided.
From there, the guide tube 21 is bent and connected to a rotary pulp recovery device 23 located below.

In such a conventional structure for coarse powder collection, the collection device operates in an air-sealed state, and the guide tube 2
1 is in a state similar to a dead end from the circular path 8, so the air containing coarse particles entering the guide pipe 21 is in a stagnant state inside the guide pipe 21. In addition, if there is a large amount of coarse powder, it will accumulate in the guide tube 21 to a considerable extent, depending on the capacity of the recovery device, and as a result, powder will accumulate on the wall of the guide tube 21, and in severe cases. As already mentioned, this may lead to r4J blockage.

Therefore, in the non-explosion example, the configuration of the guide tube is changed as shown in Figure 2 to prevent powder from adhering to the wall surface.

That is, in the embodiment shown in FIG. tube 24
A first path 25 is provided, and one end of the first path 25 is
It opens to the annular path 8 so that the coarse powder flow flowing through the annular path flows in, and the other end allows the coarse powder 1IrL flowing through the first path 25 to smoothly return to the annular path 8. They are connected in such a manner as to relate to the circular path 8. At the curved portion of the first path 25, a dropout 27 is branched and connected to a second path 26 leading to a collection device (not shown) below. In other words, the flow of coarse powder after classification is divided into two types: one that circulates along the flat egg-shaped outer peripheral wall, and the other that circulates along the flat circular ring path. Therefore, due to the influence of centrifugal force, most of the coarse powder falls into the second passage 26 and passes over it. In the figure, reference numeral 28 denotes a partition wall that separates the two circulating flows, and also serves to channel these flows n.

According to the second configuration, as the number of classification steps increases, the coarse powder that has been classified is transferred from the classification rotor 4 to the circular path 8 by centrifugal force.
leaked to! As a result of the swirling airflow at that time, the air is guided into the I+, ] path 25, which opens into the circular path. Then, it flows through the εn1 passage 25 and settles near the circular bend, falls into the second passage 26, and is collected by the coarse powder collection device. However, since the coarse powder flow in the first passage 26 can bend and return to the circular passage 8, air stagnation occurs in the first passage 25. Therefore, the problem of powder adhesion to the wall surface is greatly reduced.

Furthermore, since the second passage 26 connects to the recovery device at the bottom, it forms a dead end in a kind of air seal state.
This tank also has a structure in which the first passage 25 branches downward, so that high air stagnation does not occur, and Q n of powder adhesion to the wall is significantly reduced.

In an experiment conducted by a non-exploiter, the first and second passages described above were installed together, and the problem of powder adhesion on the surface of It has been recognized that this can be significantly improved, especially for small equipment and for classifying ultrafine powder of several micrometers, vibration imparting equipment to the guide tube! As a side effect of the embodiment, there is an advantage that the effect of paleoclassification of fine powder from coarse powder flow can be obtained.In other words, as mentioned above, In the embodiment shown in Fig. 2, introduction of the coarse powder from the first passage 25 to the second passage of the guide tube is performed by gravity settling, so the transporting action of the powder particles by the air current is greater than that for operation. (Small particles, that is, fine powder, are passed through the falling hole 27 soil by the airflow flowing in the first path 25 and returned to the circular path 8.) The amount of fine powder mixed in the 7'L of powder collected from the collecting device at the bottom is reduced accordingly.

As mentioned above, the powder separating machine of the present invention has a relatively simple structure in which the structure of the guide tube for collecting coarse powder has been improved, and the small wall surface of the powder is improved. This has the effect of reducing the need for maintenance and inspection of equipment and enabling continuous operation of the equipment for long periods of time, resulting in significant benefits.

[Brief explanation of the drawing]

Figure 9j1 Figure 1 is a longitudinal sectional view of the classifier, aB2 Figure t'', Figure 1 A-A illustrating the coarse powder guide tube which is an embodiment of the present invention
Figure 3 is a cross-sectional view taken along line A-A in Figure 1, Figure 4 is a cross-sectional view taken along line B-B in Figure 3, which explains a coarse powder guide tube with a conventional structure. . 1: Upper cousing, 2: Lower cousing, 3: Rotating shaft, 4: Classifying rotor, 5: Balance port ~
ri, 6, 7: classification blade, 8: circular path,
9: Gap hole, 10: Powder inlet, 11: Dispersion blade, 12: Gap, 13: Passage, 14: Swirl case, 15: Air inlet, 16: 7 run,
17: Swivel vane, 18 double rotation bearing, 19:
Deflector, 20: Opening, 21: Guide tube, 22
: Falling port, 232 recovery device, 24: Guide pipe,
25: 1st road, 26: 2nd road, 2
7: Fall, 28: Bulkhead.

Claims (1)

[Claims] The rotor has a large number of radial internal passages for classification chambers, and the finely dispersed powder fed into the classification chambers is transported through the rotation of the rotor and the action of air flow, and the coarse powder is distributed in the radial direction of the rotor. A classification rotor for classifying and moving fine powder to the outside and to the opposite inner side, an annular path for recirculating the outflow coarse powder provided as an outer annular path facing the classification chamber opening on the outer periphery of the classification rotor, and this annular path. In the powder classifier, the coarse powder guide tube is connected to a coarse powder recovery device from a nozzle outlet opening provided in a part of the outer peripheral wall of the powder classifier. a first conduit that curves outward from the discharge opening in the same plane as the annular path in a roughly dogleg shape and connects back to the annular path;
A powder classifier comprising: a second pipe branching from near a curved part of the pipe and connecting to the coarse powder recovery device.