JPS6039108Y2 - Powder classification device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus for classifying powder and granular materials, which is equipped with a classification impeller and an annular wind sieve member.

Conventionally, a classification impeller is provided, and by rotating the classification impeller, a centrifugal force is applied to the powder and granules, and the difference between the centrifugal force and the centripetal force accompanying the airflow is used to separate the powder and granules. In a classification device that separates fine powder and coarse powder, the fine powder passes through a classification impeller together with air to the outside of the machine, and the coarse powder descends toward the discharge port below, as shown in Figure 1. A conical annular wind sieve member 7 having a small-diameter downward opening 9 is disposed below the classification impeller 3, and an introduced air flow (hereinafter referred to as wind sieve air flow e) is used to filter the falling coarse powder. A method has been used to improve the classification accuracy of the classification device by imparting a wind sieving effect.

However, in the wind sieve member 7, the area of action in which the wind sieve airflow e can be effectively applied to the falling particles is limited to a very narrow range, approximately only on one plane. Since the particles are in a high-velocity swirling state, they are not easily affected by the wind sieving action of the air sieve e, and therefore the dispersion effect on the particles is insufficient, and the fine powder remains mixed in the coarse powder. It was something that would be discharged.

Further, the coarse powder particles that have passed through the wind sieve member 7 are further encouraged by the swirling force of the wind sieve air flow e due to the swirling energy of the particles themselves, and the particles swirl along the lower inner wall surface 11 of the main body 1. There is also the problem that the inner wall surface 11 tends to be worn out unnecessarily because the inner wall surface 11 is moved downward.

In view of the above, the present invention aims to improve the wind sieving action of the wind sieve member 7, obtain higher classification accuracy, and prevent early wear of the inner wall surface 11. Below the classification impeller 3 disposed in the upper part of the main body 1, there is a conical ring-shaped wind sieve ring 7 having an opening 9 with a small diameter at the lower end whose upper end is held on the main body 1 side, and an air inlet 1°. In this classification device, a rectifying plate 8 having an appropriate length 1 is disposed downwardly relative to the opening 9, and will be described below with reference to an embodiment.

2 and 3, inside the main body 1 of the classifier, there is a classification impeller 3 at the top, and a small diameter opening 9 below it.
The upper end of the conical air sieve ring 7 is held on the main body 1 side, and an air inlet 1 is provided below it.
0 is set.

The upper part of the main body 1 is provided with an exhaust port 6 that communicates with the inside of the classification impeller 3, and the lower part is provided with an exhaust port 5. The collector is connected.

The conveying pipe 4 is for supplying a powder material (hereinafter simply referred to as raw material P) into the classification chamber 2 together with air, and is disposed through the opening 9 from below. Classification room 2
The feeding method and structure are not particularly limited, and it may be a bark that feeds the raw material P and air separately.

By the way, a cylindrical member 8 having the same diameter as the lower end of the wind sieve ring 7, that is, the opening 9, and a suitable length 1 is continuously disposed.

Note that the appropriate length 1 of this cylindrical member 8 is not necessarily limited as a practical dimension; The size of the opening 9, the amount of air introduced, the desired particle size classified by the device, and other conditions are set appropriately.

In the above-mentioned bark, the raw material P sent into the classification chamber 2 along with air through the conveyance pipe 4 is dispersed by the swirling airflow r accompanying the rotation of the classification impeller 3 or by collision with the classification impeller 3. It is subjected to the action of classification and selection.

In other words, the raw material P is classified and sorted by the difference between the centrifugal force F by the classification impeller 3 and the centripetal force by the outflow air J passing through the classification impeller 3 and toward the exhaust port 6.
As a result, fine powder that is more susceptible to the influence of airflow j
It is also discharged from the exhaust port 6 and collected by a collector.

On the other hand, the coarse powder that overcomes the influence of the centrifugal force F descends along the wall surface while swirling with the swirling air flow r, passes through the air sieve ring 7, and reaches the opening 9. In the opening 9, the air below The air flow introduced from the inlet 10 and flowing into the classification chamber 2, that is, the air sieve air flow e, adds dispersion and sorting effects, and this causes particles to adhere to the coarse powder or to be mixed together due to agglomeration. The fine powder particles are separated from the coarse particles and returned to the classification chamber 2 again.

By the way, 1. By arranging the cylindrical member 8 in the opening 9, which is the main point of the present application, the wind sieve airflow e can come into contact with the falling particles over the entire section of the cylindrical member 8 having an appropriate length l. Compared to the past, where the area of action of the wind sieve by the wind sieve air current e was limited to almost only one plane, the opportunities for wind sieving for these particles have been greatly increased, and a reliable and good wind sieving effect can be achieved. is obtained.

In addition, the cylindrical member 8 has the advantage that it weakens the swirling force of the falling particles that reach the opening 9, making it easier to apply the wind sieving action by the subsequent wind sieving air flow e, and also because of its arrangement, The operating position of the air sieve sorting in the section 9 is shifted downward from the conventional position, and unnecessary wear of the lower inner wall surface 11 of the main body 1 due to coarse particles after the air sieve action can be significantly reduced. It is.

In this way, the fine powder from the coarse powder in the opening 9 is separated and returned to the classification chamber 2, and is classified and sorted again by the classification impeller 3 through the exhaust port 6.On the other hand, the coarse powder passes through the opening 9 and the cylindrical member 8 and descends. Then, they are discharged and collected outside the machine from the discharge port 5, respectively.

As described above, by providing the cylindrical member 8 in the opening 9 as a wind sieve sorting part, when passing through the opening 9, there is an opportunity for the falling particles to come into contact with the wind sieve air flow e, that is, in the wind sieve action area. By increasing the size, a reliable and good wind sieving effect can be obtained, improving the classification accuracy and maintaining performance, which is the most important for a classification device, and reducing the amount of air required due to the simple structure and efficient wind sieving effect. The effects of the present invention are remarkable, such as being economically advantageous.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional example, and FIG. 2 is a sectional view of a main part of this embodiment. In the figure, 1... Main body, 2... Classifying chamber, 3... Classifying impeller, 4... Conveying pipe,
5...Exhaust port, 6...Exhaust port, 7...
...Wind sieve ring, 8...Cylindrical member, 9...
...Opening, 10...Air inlet, 11.
...Inner wall surface, e...Wind sieve air flow, j...
...Outflow airflow, r...Swirling airflow, F...
...Centrifugal force, K...Centripetal force.

Claims (1)

[Scope of utility model registration request] A classification device having a classification impeller 3 arranged in the upper part of the main body 1, a conical ring-shaped wind sieve ring 7 having a lower small diameter opening 9 whose upper end is held on the main body 1 side below, and an air inlet 10. In the apparatus for classifying powder and granular materials, a cylindrical member 8 having the same diameter as the opening 9 and an appropriate length 1 is disposed continuously below the opening 9.