JPH02102768A - Classifier fitted with forcedly swirling vane - Google Patents

Abstract

PURPOSE:To improve classification efficiency by providing a rotatable swirl impeller in a casing and providing a suction port communicated with the feed port of a raw material powder. CONSTITUTION:A raw material powder supplied while being accompanied with an air flow through a feed port 3 is introduced into the feed port 3 and a feed chamber 8 of the lower layer of an impeller 4. Centrifugal force is imparted by rotation of the impeller 4 and thereby the air flow is caused and the raw material powder is accelerated and progressed to the outer peripheral direction and passed between the vanes 9 and extruded to a classification chamber 13 in the outside of the impeller 4. Coarse powder is carried farther and swirled along the outer wall of a casing 1. Fine powder is swirled inside the classification chamber 13 and raised toward a recovery chamber 7. Thereby fine powder uniform in particle size can be obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a method for classifying pulverized coal for clinker boilers, which is a raw material for cement, or powders such as grain flour such as wheat and corn, and minerals such as limestone and silica stone. This relates to a classifier with rotating vanes.

[Prior Art] Figures 5 and 6 show an example of a conventional powder classification device, in which raw powder is fed through a side supply port a along with a stream of air or inert gas. It is sent to Japan.

A cylindrical impeller C is arranged rotatably by a motor in the center of the casing b of the classifier, and on the outer periphery of the impeller C, several blades d are spaced apart from each other at regular intervals and directed toward the center. In other words, they are arranged radially from the center.

The fed raw material powder is given a centrifugal force by the rotation of the impeller C, or is repelled by the blade IIId, so that larger particles swirl around the outer periphery and finer particles swirl around the inner R section. Large particles swirling near the outer wall lose momentum as they swirl and gradually fall due to their own weight and are discharged from the lower discharge port e, while fine particles are sucked and collected from the collection port 9 at the top of the device.

[Problems to be Solved by the Invention] However, in the above device, since the raw material powder is supplied to the outside of the impeller C, sufficient centrifugal force cannot be applied to the raw material powder, and the inertia There was a drawback that the classification of tU powder and fine powder by force was not perfect, and sometimes coarse powder was mixed with fine powder and sent out from the top r.

The present invention aims to eliminate the above-mentioned drawbacks and provide a highly accurate classification device.

[Means for Solving the Problems] The present invention provides a swirl vane which is partitioned into two chambers, upper and lower, by a horizontally arranged partition wall in a casing which has a raw material powder supply port at the bottom and a fine powder collection port at the top. The wheel is rotatably driven, at least one blade is provided around the outer periphery of each chamber, and the upper blade is inclined so as to be located at the outer end or on the downstream side with respect to the direction of rotation, and the lower chamber A suction port communicating with the raw material powder supply port is provided at a lower center portion of the upper chamber, and a delivery port communicating with the fine powder recovery port is provided at a substantially center portion of the upper chamber. This applies to a classifier.

[Function] The supply port and the lower chamber of the impeller communicate with each other, and the raw material powder is directly supplied from the supply port into the lower chamber of the impeller (hereinafter referred to as the supply chamber), so when the impeller rotates, the outside A larger centrifugal force is applied than that supplied to the machine, and coarse powder and fine powder can be sufficiently separated.

In addition, the blades in the upper chamber (hereinafter referred to as the collection chamber) are arranged so that the outer ends are located on the downstream side with respect to the rotation direction (backward), so if coarse powder mixes with fine powder and rises, However, they are not able to enter the recovery room because they are repelled by the blades.

Therefore, highly accurate classification is performed, and fine powder with a narrow particle size distribution and uniform particle size can be obtained.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention, in which a recovery port 2 is provided at the center of the top of a casing 1 of a classifier, and a feed port 3 for raw material powder is provided at the center of the bottom. A cylindrical impeller 4 is arranged vertically in the center of the casing 1, a rotor shaft 5 is provided in the center of the impeller 41, and the shaft 5 is connected to a motor outside the casing 1 so as to be rotationally driven.

Inside the impeller 4, a partition wall 6 is horizontally provided at the center between the upper and lower surfaces, and the blades 1i4 are divided into upper and lower 2 parts with equal volumes.
It is divided into a layer chamber, namely a collection chamber 7 and a supply chamber 8.

A plurality of blades 9.9 are arranged at equal intervals on the outer periphery of each of the upper and lower partitioned chambers 7.8.

The blades 9 of the upper recovery chamber 7 are provided so as to be inclined (backward) so that the outer ends thereof are located on the downstream side with respect to the rotation direction.

The blades 9° of the lower supply chamber 8 may be provided radially from the center or may be provided backwards.

A suction port IO is provided at the center of the lower part of the supply chamber 8 of the impeller 4, and the supply chamber 8 is directly communicated with the supply port 3 at the center of the bottom of the casing 1 via the suction port IO.

Furthermore, a delivery port U is provided approximately at the center of the upper part of the recovery chamber 7, and the collection chamber 7 and the collection port 2 are communicated through the delivery port 11, and a coarse powder discharge port 12 is provided below the casing L side. .

The operation will be explained below.

The raw material powder is supplied along with the airflow from the supply port 3 in the lower central part of the device.
Since it communicates through the suction port IO, it immediately flows into the supply chamber 8.

Since blades 9'' are arranged on the outer periphery of the supply chamber 8, by rotating the impeller 4 with a motor, a centrifugal force is applied, an airflow is generated, the raw material powder is accelerated, and is carried on the airflow.
It advances in the outer circumferential direction, passes between the blades 9°, and is pushed out to the classification chamber 3 outside the impeller 4.

As mentioned above, the raw material powder is supplied to the inside of the impeller 4 and is accelerated by the blades 9° and exits to the outside, so that a sufficiently large centrifugal force is applied to the tU powder, and the tU powder is carried further, and the tU powder is transported further to the casing l. Rotate along the outer wall.

The fine powder swirls relatively inside the classification chamber 13, overcomes the centrifugal force, and rises toward the collection chamber 7, but at this time, the blades 9 of the upper collection chamber 7 are arranged backwards. Therefore, even relatively small particles are repelled by the blades 9 and cannot enter the collection chamber 7.

Only very fine particles can pass between the blades 9 and enter the collection chamber 7.

The fine particles are transported to the outside from the outlet 11 of the recovery chamber 7 through the upper recovery port 2.

The ill powder rotates along the outer wall of the casing 1, loses its motion, gradually descends due to its own weight, and is discharged from the discharge port 12 provided on the side.

By changing the size of the blades 9, 9°, the angle of inclination, the rotational speed of the impeller 4, etc., it is possible to obtain powder having a uniform particle size distribution with any narrow blade.

As described above, the apparatus of the present invention can perform efficient classification with a small volume.

It should be noted that the forced swirling blade classifier of the present invention is not limited to the above-described embodiments, and it goes without saying that various changes may be made without departing from the gist of the present invention.

[Effects of the Invention] As explained above, according to the forced swirling blade classifier of the present invention, various excellent effects as described below can be achieved.

Since the supply port and the supply chamber of the impeller are in communication, the raw material powder is supplied into the impeller, and the rotation of the impeller applies sufficient centrifugal force to sufficiently classify coarse powder and fine powder. be exposed.

Furthermore, even if the coarse powder after classification tries to enter the collection chamber, since the blades of the collection chamber are provided backwards, it will be repelled and will not be able to enter.

Only very fine particles are collected.

Therefore, classification is complete and fine powder with uniform particle size can be obtained.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention, FIG. 2 is a view taken along the line A-A in FIG. 1, FIG. 3 is a view taken along line B-B in FIG. 1, and FIG. 5 is a side sectional view showing the conventional example, and FIG. 6 is a view taken along the line C--C in FIG. 5. 2 is a collection port, 3 is a supply port, 4 is an impeller, 6 is a partition wall, 7
is the upper chamber (recovery chamber), 8 is the lower chamber (supply chamber), 9 is the blade of the collection chamber, 9° is the blade of the supply chamber, IO is the suction port, 1
1 is a delivery port, and 13 is a classification chamber.

Claims (1)

[Claims] 1) In a casing that has a raw material powder supply port at the bottom and a fine powder collection port at the top, a rotating impeller partitioned into two chambers, an upper and a lower chamber, by a horizontally arranged partition wall is provided so as to be rotatable. At least one blade is provided around the periphery, and the blade in the upper chamber is inclined so that the outer end is located on the downstream side with respect to the rotation direction, and the raw material powder is further provided in the lower center of the lower chamber. A classifier with forced swirling blades, characterized in that a suction port is provided that communicates with the supply port, and a delivery port that communicates with the fine powder recovery port is provided in the upper center of the upper chamber.