JPH0760142A - Air classifier - Google Patents

Abstract

PURPOSE:To adjust the crushing capacity in an air classifier, wherein a raw material inlet and a pin mill are provided in a dispersion chamber on the upper face side of a classifying rotor and the dispersion chamber is allowed to communicate with a classification chamber, by furnishing a detachable pin of the pin mill. CONSTITUTION:A supporting ring R provided with a desired detachable pin 9 is selected and fixed to a dispersion chamber 12, the switching valve V of a raw material supply means 7 is opened to close an outer feed port 7b and to open an inner feed port 7a. Classifying air SA is sent through a guide vane 4 to form a free spiral flow in a classification chamber 11, a rotor shaft 13 is rotated to rotate the classifying block 3, and hence a forced spiral flow is formed and flows into an exhaust duct 6 as an ascending air current. Under such conditions, fly ash F is charged into the means 7, discharged into the dispersion chamber 12, crushed by a pin mill M, dispersed, collided with the inner wall 5 and dropped into the classification chamber 11. The fly ash F is classified into a fine powder S and a coarse powder L by the balancing action between the centrifugal force and air resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air classifier used for treating fly ash and the like.

[0002]

2. Description of the Related Art Fly ash (also called coal ash) generated from a pulverized coal-fired boiler or the like is classified into a fine powder and a coarse powder, which is used as a raw material for cement, and the coarse powder is an artificial lightweight aggregate. It is used as a raw material.

The fly ash contains unburned coal, which has a relatively large particle size. Therefore, when the fly ash is classified, the unburned coal is recovered almost on the coarse powder side, which results in a significant restriction on the use of the classified coarse powder.

Therefore, in view of the fact that a large amount of unburned coal in fly ash is present in the coarse powder particles, and that the unburned coal is more easily crushed than fly ash, "after crushing fly ash, fine powder and coarse powder are produced. A method of processing fly ash for classification ”has been developed.

This processing method is carried out by using the following air classifier. That is, a dispersion chamber is provided on the upper surface side of the classification rotor, a raw material inlet and a pin mill are provided in the dispersion chamber,
An air classifier, wherein the dispersion chamber is communicated with the classification chamber on the side of the classification rotor.

[0006]

A conventional pin mill of an air classifier has a rotating pin fixed to the upper surface of a classifying rotor,
Since the fixing pin is fixed to the casing of the dispersion chamber, the number of rotations of the classification rotor and the rotation pin is the same.

Since the rotation speed of the classification rotor is determined based on only the classification point without considering the grinding force of the pin mill, the rotating pin of the pin mill does not always rotate at a desired rotation speed. Therefore, the crushing function cannot be adjusted according to the situation of fly ash, and the raw material may be excessively crushed to become fine powder.

Therefore, it is conceivable that the pin mill and the classification rotor are provided with separate driving means so that they can rotate independently of each other. However, if the two are made independent in this way, the structure of the air classifier becomes complicated, and the cost of the device and the maintenance fee is inevitably increased.

The present invention has been made in view of the above circumstances and has as its object the adjustment of the crushing ability.

According to the present invention, a dispersion chamber is provided on the upper surface side of the classification rotor, and a raw material feeding means and a pin mill are provided in the dispersion chamber.
In the classifier in which the dispersion chamber is connected to the classification chamber on the side of the classification rotor, the pin of the pin mill is detachably provided, and the raw material feeding means is capable of adjusting the feed position of the raw material. An air classifier characterized by:

[0011]

The number of revolutions of the classification rotor is set so as to obtain a desired classification point, and the pin of the pin mill is not attached or detached so that the desired pulverized state is obtained, and the raw material feeding position of the raw material feeding means is adjusted. When the classification rotor is rotated and the fly ash is supplied to the raw material charging means, the fly ash is crushed by the pin mill and then dropped into the classification chamber to be classified into fine particles and coarse powder.

[0012]

Embodiments of the present invention will be described with reference to the accompanying drawings.
A rotor shaft 13 is provided in the center of the casing 1, and a rotor with a classification blade 3 (classification rotor) 2 is arranged on the shaft 13. Guide vanes 4 are provided on the outer periphery of the classification blade 3 via a classification chamber 11.

The classification chamber 11 has an upper surface 2a of the rotor 2.
It communicates with the dispersion chamber 12 provided on the side. This dispersion chamber 12
Includes an inner wall 5 of the casing 1 that functions as a collision plate, a pin mill M, and a raw material charging means 7.

The pin mill M includes a rotating pin 8 and a removable pin 9.
It consists of and. The rotating pins 8 are fixed to the upper surface 2a of the rotor 2, and a plurality of the pins 8 are arranged at intervals in the circumferential direction. The spacing between the pins 8 and the thickness, shape, etc. of the pins 8 are appropriately selected as necessary.

The attachment / detachment pin 9 is fixed to the support ring R. The plurality of pins 9 are arranged at intervals in the circumferential direction, but the intervals between the pins 9 and the thickness of the pins 9,
The shape and the like are appropriately selected as needed.

The raw material feeding means 7 has an inner supply port 7a provided inside the pins 8 and 9, an outer supply port 7b provided outside thereof, and a switching valve V provided at the branching portion 7c. I have it.

Next, the operation of this embodiment will be described. A support ring R provided with a desired attachment / detachment pin 9 is selected from among several types of support rings R prepared, the support ring R is mounted on the upper surface 12a of the dispersion chamber 12, and the switching valve V of the raw material feeding means 7 is selected. Is operated to close the outer supply port 7b and open the inner supply port 7a.

Classifying air SA is sent to the classifying chamber 11 through the guide vanes 4 to form a free vortex in the classifying chamber 11, and the rotor shaft 13 is rotated at a predetermined rotational speed by a driving means (not shown). Then, the classification blade 3 rotates to form a forced vortex flow, and the vortex flow swirls through the classification chamber 11 to pass between the classification blades 3 and rise into the exhaust duct 6 as an updraft.

In this state, when the fly ash F is charged into the raw material charging means 7, the fly ash F falls through the inner supply port 7a into the dispersion chamber 12 and is dispersed while being crushed by the pin mill M.

In this crushing, the coal ash in the fly ash F is a crushed material having poor grindability, that is, a hard crushed material,
Further, since the unburned coal in the fly ash F is a crushed material having good grindability, that is, a soft crushed material, the crushing of the unburned coal proceeds faster than that of the coal ash. Therefore, the unburned coal is crushed into fine powder before the pulverization of coarse-grained coal ash progresses so much.

The fly ash F in the dispersion chamber 12 is crushed as described above, and then collides with the inner wall 5, the traveling direction of the fly ash F is changed, and the fly ash F falls into the classification chamber 11.

In the classifying chamber 11, the fly ash F is created by the balance action of centrifugal force and air resistance.
For example, a fine powder S having a powder particle size of less than 20 μm and a powder particle size of 20 μm
It is classified into the above coarse powder L.

The fine powder S-shaped fly ash and unburned charcoal ride on an ascending air stream, pass through the opening 2b of the classification rotor 2 and enter the fine powder exhaust duct 6, and are collected by the air filter 23.

The coarse powder L falls from the discharge port 18 into the container 24 while swirling in the hopper 10. This coarse powder L
Is almost coal ash, and the amount of unburned coal is very small. Therefore, the coarse powder L in the container 24 can be used as a building material, for example, a raw material of an artificial lightweight aggregate.

FIG. 3 is a view showing another state of use. What is different from FIG. 1 is that the switching valve V is switched in the opposite direction to that of FIG. That is, the inner supply port 7a is closed and the raw material is supplied only to the outer supply port 7b. In this way, the raw material is less susceptible to the crushing action of the pin as compared with FIG. it can.

FIG. 4 is a diagram showing still another usage condition, and FIG.
Is that the support ring R is removed from the dispersion chamber 12 and the attachment / detachment pin 9 is removed from the dispersion chamber 12. By doing so, only the rotating pin of the pin mill remains in the dispersion chamber, so that the pulverizing ability is further reduced. This mode of use is particularly effective for preventing over-crushing of the raw material when the classification rotor 2 is rotated at a particularly high speed in order to make the classification point fine.

The embodiment of the present invention is not limited to the above. For example, instead of fixing the attachment / detachment pin 9 of the pin mill M to the support ring R, each attachment / detachment pin 9 is directly attached to the dispersion chamber 1.
The two casings 1 may be detachably provided, or the rotating pin 8 may be detachably provided on the upper surface 2a of the rotor 2.

The raw material charging means 7 has a pipe branched bifurcated through a switching valve V to form an inner supply port 7a and an outer supply port 7b. Instead of this, two pipes are provided. That is, the pipe dedicated to the inner supply port and the pipe dedicated to the outer supply port may be separately provided.

Further, the raw material feeding means 7 is formed of one pipe, and the outlet of this pipe is movably provided along the upper surface 12a of the dispersion chamber 12, so that the raw material is supplied to the inside or the outside of the pin mill M. be able to.

In the above-mentioned embodiment, the pin mill M is driven by the rotation of the classification rotor 2, but instead of this,
Both may be configured to be rotatable independently of each other, and both may be provided with separate drive means.

[0031]

According to the present invention, since the pin of the pin mill is detachably provided, it is possible to adjust the mounting state of the pin as necessary, so that a desired crushing force can be obtained. Further, the raw material feeding means can adjust the feed position of the raw material, so that the feed position of the raw material can be adjusted to the inside or the outside of the pin mill to adjust the crushing force received by the raw material, if necessary. Therefore, even if the number of rotations of the rotor is determined based on the classification point of the raw material, the grinding force of the pin mill is adjusted,
Since it can be crushed with a desired crushing degree, unlike the conventional example, the problem of excessive crushing does not occur.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a support ring.

FIG. 3 is a vertical cross-sectional view showing another usage state.

FIG. 4 is a vertical cross-sectional view showing another usage state.

[Explanation of symbols]

 2 Classification rotor 7 Raw material charging means 7a Inner supply port 7b Outer supply port 8 Rotating pin 9 Attachment / detachment pin 11 Classification chamber 12 Dispersion chamber M Pin mill R Support ring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Utsuka Tamashige, 2-4 Daisaku, Sakura-shi, Chiba Prefecture Onoda Cement Co., Ltd. (72) Inventor Satoru Fujii 6276 Onoda, Onoda City, Yamaguchi Prefecture Onoda Cement Within the corporation

Claims (7)

[Claims] 1. An air classifier in which a dispersion chamber is provided on the upper surface side of a classification rotor, a raw material charging means and a pin mill are provided in the dispersion chamber, and the dispersion chamber is connected to the classification chamber on the side of the classification rotor. An air classifier, wherein the pin of the pin mill is detachably provided. 2. An air classifier in which a dispersion chamber is provided on the upper surface side of the classification rotor, a raw material charging means and a pin mill are provided in the dispersion chamber, and the dispersion chamber is connected to the classification chamber on the side of the classification rotor. An air classifier, wherein the raw material charging means is capable of adjusting a raw material supply position. 3. An air classifier in which a dispersion chamber is provided on the upper surface side of a classification rotor, a raw material charging means and a pin mill are provided in the dispersion chamber, and the dispersion chamber is connected to the classification chamber on the side of the classification rotor. The pin of the pin mill is detachably installed,
Further, the raw material charging means is capable of adjusting a raw material supply position, and is an air classifier. 4. The air classification according to claim 1, 2 or 3, wherein the pin mill includes a rotating pin fixed to the upper surface of the classification rotor and a detachable pin provided on the upper surface of the dispersion chamber. Machine. 5. The air classifier according to claim 1, 2, or 3, wherein the removable pin is fixed to the support ring. 6. The raw material charging means is provided with an inner supply port and an outer supply port.
Air classifier described. 7. The inner supply port and the outer supply port are switched by a switching valve.
Air classifier described.