JPH05253547A - Classifying apparatus - Google Patents

Abstract

PURPOSE:To classify a mixture of fibers and shots into respective components with high accuracy by providing a repulsive force buffering member at the position opposed to the supply direction of a supply nozzle and providing a buffer layer to the repulsive force buffering member. CONSTITUTION:An air stream mixed with fibers and shots is supplied toward space as an air jet from the tip part 17 of a supply nozzle 3. This mixed air stream is formed by continuously mixing and dispersing a definite amount of a mixture of fibers and shots and a definite amount of air by an ejector. A recessed part 16 is provided to the side wall of a block 6 at the position opposed to the supply direction of the supply nozzle 3 in the positional relation almost opposed to the supply nozzle 3 through the space 1. A repulsive force buffering member 12 is arranged so as to cover the recessed part 16 and a buffer space 18 is present between the recessed part 16 and the repulsive force buffer member 12 as a buffer layer and the recessed part 16 and the repulsive force buffering member 12 are set to a sufficient size at the position where all of shots flying from the supply nozzle 3 impinge against the repulsive force buffering part 12.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a classifying device suitable for separating fibers and particles.

[0002]

BACKGROUND OF THE INVENTION Generally, inorganic fibers such as alumina-
Silica-based fibers, rock wool, glass fibers and the like are produced by thinly stretching a viscous solution-like raw material. Such a production operation is called fiberizing. There are various methods for fiberizing, and the fibers produced by any of the methods are roughly classified into fibers in a continuous state and aggregates of relatively short fibers (short fibers) in many cases.

The inorganic fibers produced in this way are also
It is rarely used as it is. Usually, it is secondary processed. Then, at the time of the secondary processing, it is cut into an appropriate length if necessary.

Generally, the fibers processed in this manner contain foreign substances. This foreign substance is called a shot. Most of the shots are small lumps which are not fibrous and are solidified in another shape, and include various shapes such as a spherical shape, a droplet shape, and a flake shape. In addition, such shots include short and extremely thick fibers.

When foreign matters other than the fibers are present, the foreign matters are separated from the fibers and eliminated. The degree of separation is set according to the purpose. In some cases, the foreign matter is completely separated, and in other cases, a part is left. Including both, such separation is called classification.

According to the conventional classification method, water or air is used as a medium, and classification is performed by utilizing the difference in the mobility of the fiber and the shot dispersed in the flowing medium. Specifically, classification is performed by utilizing the difference in sedimentation velocity between the shot and the fiber and the difference in inertial force (or centrifugal force). Generally, a classifier that utilizes inertial force is often used from the viewpoint of work efficiency. Examples of such classifiers include various airflow classifiers and wet classifiers. A typical device as an airflow classifier is a cyclone. The cyclone is also used as a wet classifier. The former uses air as the medium and the latter uses water as the medium. In both cases, a raw material containing fibers and shots is dispersed in a swirling fluid medium, and the difference in inertial force is used.

[0007]

Generally, many shots mixed between fibers are not all the same size,
Their size has a certain distribution. For example, the majority of shots contained in a ceramic fiber having an average fiber diameter of 2 to 3 μm are spherical and have a diameter distribution of 10 to 500 μm. In this case, the ratio between the minimum value and the maximum value of the shot mass is approximately 1:10.
In many cases. Therefore, the ratio of the minimum value to the maximum value of the inertial force is about 1: 100,000. Therefore, in order to accurately classify shots from fibers using the inertial force, if the minimum inertial force is 1, the machine must be able to handle 100,000 times the inertial force.

The conventional shot classifier cannot accurately handle shots having such a large mass distribution.

A first object of the present invention is to provide a classifying device which can classify fibers and shots from a mixture of fibers and shots with high precision.

A second object of the present invention is to provide a classifying device capable of highly accurately classifying a shot of an arbitrarily set size from a mixture of fibers and shots.

[0011]

SUMMARY OF THE INVENTION The gist of the present invention is a classifying device for classifying an object to be classified in a jet by jetting a jet from the feed nozzle along a Coanda block. The classifying device is characterized in that a repulsive force cushioning member is provided at a position where the repulsive force is exerted, and a buffer layer is attached to the repulsive force cushioning member.

The Coanda block used in the classification device of the present invention is a block utilizing the Coanda effect. As is well known, jets ejecting along a wall have the property of flowing even if the wall is curved, but the jet flow adheres to a convex curved surface such as a cylindrical surface. Is called the Coanda effect.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a classification device of the present invention.

In FIG. 1, five blocks 2, 4, 5, 6, 7 are provided around the space 1. Each of these blocks 2, 4, 5, 6, 7 is a hard block made of wear resistant material. For example, as the material of the block, a metallic material such as stainless steel or tungsten carbide, or a ceramic material such as zirconia or alumina is used.

These blocks 2, 4, 5, 6, 7 have the same length in the direction perpendicular to the paper surface of FIG. And each block 2, 4, so that the whole becomes almost rectangular parallelepiped
Reference numerals 5, 6 and 7 have an upper surface and a lower surface parallel to the paper surface, and are sandwiched by two plates (not shown) so as to cover the upper and lower surfaces thereof. Usually these plates are made of transparent glass for easy viewing inside.

The blocks 2, 4, 6 are fixed blocks. One of the blocks 2 is specifically called a Coanda block. The Coanda block 2 has a smooth convex curved surface 15 so as to exert the Coanda effect.

Reference numerals 8, 9, 10, 11 are flow passages formed by these blocks 2, 4, 5, 6, 7 and extending in the vertical direction, all of which are connected to the space 1. That is,
The space 1 exists at a central position connecting the respective flow paths 8, 9, 10, 11 to each other. Shots (not shown) for the purpose of separation fly in this space 1.

One intermediate block 5 divides one wide flow passage to form a plurality of flow passages 8 and 9, and mainly, the direction and flow state of the air flow flowing through the respective flow passages 8 and 9. Is the optimal state. The other middle block 7 divides one wide flow path into a plurality of flow paths 10,
11 is formed, and is mainly for adjusting the classified state.

The intermediate block 5 and the block 7 can be moved and adjusted in position and orientation as required. Preferably, the blocks 5 and 7 are divided into two parts in the lengthwise direction to form a space. The portion located on the first side is a movable portion, and the movable portions rotate around an appropriate fulcrum, respectively, so that the edges 5a, 7 facing the space 1 are formed.
The direction or position of a can be adjusted.

Although the number of the lower middle blocks 7 shown in FIG. 1 is one, as will be described later with reference to FIG. It is also possible to provide a plurality. In this case, it is possible to classify the size of the shot in several stages according to the number of blocks 7.

The supply nozzle 3 is a convex curved surface 15 of the block 2.
It is provided close to. That is, the tip portion 17 of the supply nozzle 3 is arranged very close to the curved surface 15 of the block 2. In FIG. 1, a part of the side wall of the supply nozzle 3 shares a part of the side wall of the block 2.

From the tip portion 17 of the supply nozzle 3, a mixed air flow of fibers and shots is supplied to the space 1 as an air jet. Although not shown in the figure, this mixed air flow is a mixture of a certain amount of the fiber-shot mixture and a certain amount of air continuously dispersed by a known ejector device. The fiber and shot mixture needs to be well dispersed in the air jet, but for the same size air jet, if the fibers are too long, dispersion becomes difficult. The amount and pressure of the air jet used must be balanced with other air flows, so it cannot be increased unnecessarily. However, if the average fiber length is 5 mm or less, the dispersion is relatively easy. Especially the average fiber length is 1000 μm
Dispersion is easier if:

The side wall of the block 6 is provided with a recess 16 at a position facing the supply direction of the supply nozzle 3. The concave portion 16 is in a positional relationship substantially facing the supply nozzle 3 via the space 1.

Repulsive force cushioning member 12 so as to cover the concave portion 16.
Are arranged. A buffer space 18 exists between the recess 16 and the repulsive force buffer member 12 as a buffer layer.

The recess 16 and the repulsive force buffering member 12 are set in such a position that they hit all the shots coming from the supply nozzle 3 and in a sufficient size.

The repulsive force buffer member 12 is the recess 1 of the block 6.
It is attached at 6 and forms part of the side wall of the space 1 and forms part of the passage wall for the air flow flowing from the direction of the flow path 9 to the direction of the flow path 10. The passage wall including the block 6 and the repulsion force buffer member 12 constitutes a smooth wall surface as a whole.

It is desirable that the repulsive force buffering member 12 is made of a material which itself is wear resistant and absorbs and attenuates external force. Various rubbers and polymer resins are easily available as such materials. In particular, a sheet-like material having a thickness of 0.5 to 1.5 mm at a shot hitting portion is preferable. For example, neoprene rubber or silicone rubber is the most suitable material for the rubber. Further, rubber having excellent damping characteristics against vibration is more preferable. The repulsion force buffer member 12 is fixed to the block 6 at a part or the whole of its periphery.

The method of fixing the repulsion force buffer member 12 is not limited. For example, like a curtain, only the upper part may be fixed and the lower part may be the free end. In this case, the flow paths 8 and 9 are arranged so as to be on the upper side, and the flow paths 10 and 14 are arranged on the lower side. As another fixing method, blocks 2, 4, 5,
The edges may be attached to the upper and lower glass plates (not shown) sandwiching 6,7. Further, as another fixing mode, the repulsion force buffer member 12 may be completely separated from the block 6. In this case, it is not necessary to form the concave portion 16 in the block 6.

The means for fixing the repulsive force buffering member 12 is optional, but means such as screwing or adhesion can be mainly used.
Usually, the buffer space 18 is formed by providing the block 6 with the recessed portion 16, but in another embodiment, the repulsive force buffering member 12 having the recessed portion on one surface or formed in the recessed portion.
It is also possible to use so that the concave portion serves as the buffer space 18.

The cushioning layer attached to the repulsive force cushioning member 12 can be configured in other modes. It is also possible to use one having large and small spaces arranged inside the repulsive force buffering member 12 and one having liquids such as water arranged in the large and small spaces. Also,
The elastic member having a considerable thickness has the buffer layer in itself.

Each of the flow paths 10 and 11 is connected to a blower (not shown) via a collector and is in a depressurized state.

Further, the flow paths 8 and 9 are dampers (not shown).
Through a muffler (not shown), and the end of the muffler is open to the lower atmosphere. This opening serves as an air intake.

When using the above-mentioned classification device, the flow path 1
By the operation of the blower connected to the rear part of 0 and 11, the flow paths 8 to 11 and the space 1 are depressurized, and a large amount of air is drawn into the flow paths 8 and 9 through the damper. Most of the air drawn into the flow channel 9 flows toward the flow channel 10. Similarly, most of the air drawn into the flow path 8 flows toward the flow path 10. These air streams are preferably laminar.

Air containing fibers and shots is blown from the supply nozzle 3 as a jet. Although this air jet is blown out in the direction of the space 1, it is blown out in contact with the Coanda block 2, so that the Coanda effect causes
It flows along the curved surface 15 while being in contact with the Coanda block 2. That is, it flows along the curved surface 15 along a locus as shown by an arrow 14 in FIG.

As described above, both the fiber and the shot are blown from the supply nozzle 3 onto the air jet into the space 1 with an inertial force, and the air jet is eventually curved.
Change direction because it flows along 5. Since the fiber and the shot have an inertial force acting so as to go straight in the ejection direction of the air jet, they move so as to separate from the air jet that changes the direction. However, in order to leave the air jet, an inertial force sufficient to overcome the fluid resistance of the air jet is required.

Since the fiber has a small mass, the inertial force is small and, conversely, its shape is elongated, so that the fluid resistance received from the air jet is sufficiently large. As a result, the fibers fly along the Coanda block 2 in the trajectory of the arrow 14 while being captured by the air jet without being separated from the air jet.

On the other hand, since the shot has a large mass and a spherical shape, the shot overcomes the fluid resistance of the carrier air and flies toward the center of the space 1. The locus drawn by this direction is illustrated by an arrow 13. The shot attempting to draw the locus of the arrow 13 receives fluid resistance from the airflow flowing from the flow paths 8 and 9 and is pushed to the flow paths 11 and 10. The shot swept away is divided into the flow path 10 side or the flow path 11 side by the edge 7a of the block 7. Which channel is shot 1
Whether it flows to 0 or 11, the size of the shot, the speed of the air flow,
It depends on the size of the space 1 and the position of the edge 7a. The position of the edge 7a can be adjusted as described above. Edge 7
When a is located closer to the block 2, the particle size of the shot flowing into the flow channel 11 becomes smaller. Further, by adjusting the position of the edge 7a of the block 7, the shot flowing to the flow path 11 side can be made zero.

In general, the particle size of shots is distributed from small to fairly large. For example, in the case of alumina-silica ceramic fiber, the diameter of the shot is approximately 0.001 to 0.5 mm. In order to fly the smaller one of these shots in the direction of arrow 13, it is necessary to give a large inertial force necessary for it. This effect is added to the larger shot at the same time by the mechanism of the ejector. As a result, a particularly large shot flies in the direction of arrow 13 with a very large inertial force. Therefore, some of the large shots collide with the repulsive force buffering member 12 without being swept in the direction of the flow path 10 by the airflow flowing from the flow path 9 toward the flow path 10. Such a shot is a repulsive force cushioning member 1 having a cushioning space 18 attached to the back.
The kinetic energy is absorbed by 2 and flows toward the flow path 10 with almost no repulsion.

A reliable kinetic energy absorbing action of the repulsive force buffering member 12 is realized by the presence of the buffering space 18 provided behind the repulsive force buffering member 12. When the buffer space 18 is present, the repulsive force buffer member 12 can absorb its kinetic energy while effectively deforming against the impact of the shot. On the contrary, when the repulsive force cushioning member 12 is not provided, the shot collides with the abrasion resistant block 6. Abrasion resistant blocks generally have high hardness, and therefore high elastic energy, so that the shot is repelled. This tendency is particularly remarkable when the block 6 is made of ceramic.

When the thin sheet-shaped repulsive force buffer member 12 is provided in contact with the wall surface of the block 6 with an adhesive or the like, the buffer space 18 is not provided behind it, so that a large shot will block the repulsive force. The cushioning member 12 does not sufficiently absorb the kinetic energy, but is repelled by the elastic force of the repulsion cushioning member 12 and bounces in the opposite direction. As a result, as in almost the case where the repulsive force buffering member 12 is not provided, a considerable amount of shots jump over the edge 7a of the block 7 into the flow path 11. For this reason, the separation of the fiber and shot is not perfect.

The classifier of the present invention can almost completely separate fibers from large shots to small shots. It is effective not only for complete separation but also for an appropriate degree of separation. These adjustments are possible by adjusting the direction or position of the edge 7a of the block 7. By appropriately dividing the flow channel 10 and the flow channel 11 using the block 7, it is possible to cause a shot larger than a set size to flow into the flow channel 10 and a shot smaller than that or a fiber to flow into the flow channel 11.

FIG. 2 shows an example in which a block 19 having the same function as the block 7 in FIG. 1 is added. By adjusting the positions of the edges 7a and 19a of the blocks 7 and 19, the size of the shot to be classified can be divided. When the flow rate of the airflow flowing through each of the flow paths 10, 11 and 20 and the position of each of the edges 7a and 19a are appropriately adjusted, fibers are provided in the flow path 11 and relatively small shots of a predetermined size are provided in the flow path 20. However, relatively large shots of a predetermined size are classified in the channel 10. In this way, by arranging the plurality of blocks 7 and 19 so that the plurality of edges 7a and 19a are arranged along the flight path of the shot, it is possible to separate into shots of a plurality of sizes.

The classifying device of the present invention is not only capable of classifying fibers and shots or shots and shots from a mixture of shots and fibers with high precision, but also the separation of fibers and shots can be understood from the principle. In addition, it is possible to classify substances with other substances having extremely different masses with high accuracy.

The classifying device of the present invention is suitable for classifying or separating a fibrous material and a particulate material having a diameter larger than at least the diameter of the fiber. in this case,
The material of the fiber does not matter. However, the particles are preferably hard and include those having a considerably large mass as compared with the mass of the fiber. For example, it is a mixture of various types of pulp and granular foreign substances such as sand and metal, and granular foreign substances of the same material as or different materials from various whiskers. Not only a mixture of fibers and particles, but also a powder having a certain distribution, in which the difference in mass between particles having a small diameter and particles having a large diameter (for example, 500 μm) is extremely large, for example, 100,000 times. Large particles that are hard and have a large repulsion against metals and ceramics, such as glass beads, metal beads, and various mineral powders are also suitable as classification targets in the present invention.

Mixtures of flakes and hard particles, such as mica flakes and other mineral particles, paper flakes and mineral particles and metal particles, can also be classified by the apparatus of the present invention.

Further, in the present invention, the material to be classified is supplied from the supply nozzle 3 to the space 1 by the air jet.
Send to. At this time, the raw material is sent as a transportation medium by being carried on a jet stream of air. The jet-stream-like transport medium used in this case is broadly called an air jet in the present invention. On the other hand, in the present invention, the airflow refers to a high-speed airflow flowing from one side to the other side. It is preferable that this air flow be flowing even when the air jet is not blown. When an air jet is blown, it cannot be said exactly, but in principle, the air flow and the air jet flow in parallel without mixing. At this time, the air jet flows along the Coanda block 2. However, there is no difference in that both the air flow and the air jet are high-speed air flows, and in other words, if they are forcibly used, only the purpose of use and the place where they flow are different, and there is no essential difference between the two.

Experimental Example Alumina-silica ceramic fibers having an alumina content of 48% were preliminarily subjected to a vibration mill and cut so as to have an average fiber length of 100 microns to obtain a raw material. The fiber diameter of this fiber was distributed in the range of 0.5 to 10 μm, and the average fiber diameter was 2.9 μm.

Then, the apparatus shown in FIG. 1 is divided into a state in which the repulsive force buffering member 12 is provided and a state in which the repulsive force buffering member 12 is not provided, and a classification test of fibers and shots in the raw material is performed for each. went. The amount of residual shot remaining on the fiber side of the obtained fiber was measured.

As a condition of the classifying device, the flow path 10 has a flow rate of 7 per minute.
Air of 5 cubic meters per minute was flowed in the cubic meter and the flow path 11. Further, 0.18 cubic meters of air per minute was made to flow from the supply nozzle 3 as an air jet at 0.5 atmospheric pressure. The fibers obtained by classification were each dispersed in water and carefully separated into shots and fibers by a water sieving method. Then, the obtained shot is dried and sieved to 212 μm or more, 212 to 15
After sieving into each size of 0 μm and 150 to 45 μm,
Each weight was measured and the ratio of the residual shot to the fibers obtained by the original classification was determined.

The results obtained are shown in Table 1. The measurement results with the repulsive force cushioning member 12 are shown as Experimental Example 1 and Experimental Example 2, and the measurement results without the repulsive force cushioning member 12 are shown as Comparative Example 1 and Comparative Example 2. In addition, the shot content rate of the original material is shown as Reference Example 1.

[0051]

[Table 1]

[0052]

EFFECT OF THE INVENTION The total amount of residual shots of Experimental Example 1 and Experimental Example 2 in Table 1 is about 1/4 of the total amount of residual shots of Comparative Example 1 and Comparative Example 2. In particular, when the two shots are compared with respect to the residual shots of 212 μm or more, the experimental examples are 1/10 or less of the comparative examples.

Further, in each experimental example, the amount of shots remaining in the fiber is 0.5% or less of the shot content in the original raw material.

As described above, it was found that the fibers and the shots can be classified with extremely high accuracy by providing the cushioning space in the repulsive force cushioning member.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a classification device according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a classification device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Space 2 Coanda Block 3 Supply Nozzle 4,5,6,7 Block 8,9,10,11 Flow Path 12 Repulsion Force Buffer Member 13 Shot Path 14 Fiber Path 15 Curved Surface 16 Recess 18 Buffer Space 19 Block 20 Flow Path ◆

Claims (1)

[Claims] 1. A classifying device for classifying an object to be classified in a jet by jetting a jet along a Coanda block from the feed nozzle, wherein a repulsive force buffering member is provided at a position facing the feed direction of the feed nozzle. With
A classifying device characterized in that a buffer layer is attached to the repulsive force buffer member.