JPH06142615A - Classifying equipment - Google Patents

Abstract

PURPOSE:To provide the classifying equipment which is excellent in its fine powder yield, and also, can hold classification accuracy even for high density power. CONSTITUTION:The classifying equipment consists of a classifying device 2, a cyclone connected thereto, a return tube for allowing dust containing gas exhasted from the cyclone to recirculate to an original powder supply part of the classifying device 2, and a suction fan provided on the way of the return tube. Also, in the classifying device 2, a supply tube 16 is provided in a vertical cylindrical casing 2a, a dispersing plate 15 is provided fixedly in the upper part and a hollow tube 3 provided peripherally with a classifying blade 12 right under the dispersing plate 15 is supported axially so as to be freely rotatable on the center shaft of the casing 2a, a discharge port 20 for discharging air containing fine powder is provided in the lower end of the hollow tube 3, a horizontal disk 80 is provided on the inside peripheral side of the casing in the lower part of the classifying blade 12, and also, plural pieces of stirring blades 70 are provided peripherally thereon.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] The classification equipment of the present invention is a classification equipment for efficiently separating raw material powders of chemicals used in the ceramics industry and filler industry into coarse powder and fine powder. The present invention relates to classification equipment for improving the yield of fine powder.

[0002]

2. Description of the Related Art A classifier is intended to classify powders and granules crushed by a crusher into a product having a required particle size by an air flow, and to classify them into products. Centrifugal force classification, which is roughly classified into classification and centrifugal force classification, and which is suitable for mass classification of powders, includes a free vortex type in which the air flow is swirled by making the shape of the classification chamber spiral, and a classification chamber There are a forced vortex that forcibly swirls the air flow by the rotating blades installed in the wing, and a combined vortex that is a combination of these two, a free vortex and a forced vortex.

Further, the classifying device includes a device for guiding powder particles crushed by a crusher and provided separately from the crusher, and a powder provided in the crusher in a crushing chamber. There is an accessory type in which particles are introduced into the classification chamber by air flow and classified, but the latter type has a wide range of uses and is often used as an accessory to a crushing device.

[0004]

Recently, the demand for the particle size distribution of products has become higher with the diversification of pulverized raw materials and the expansion of the demand for ultrafine powder in high-priced and high-quality special materials. There is an increasing demand for products that not only specify a very small average particle size but also keep the passing amount of a specified particle size much smaller than the average particle size within a certain ratio. Along with this, there has been a demand for more sophisticated classifiers. Fine powders are extracted from fairly fine raw powders of the order of microns, and fine powders mixed in coarse powders after classification are also required. It has been desired to improve the yield of fine powder by reducing the amount as much as possible and collecting it as fine powder. In addition, in so-called high-concentration classification, in which the amount of raw material powder is large relative to the supply air flow, there is a problem that the fine powder yield decreases and the classification accuracy deteriorates.

[0005]

In order to meet these requirements, the classification equipment of the present invention comprises a classification device, a cyclone connected to the classification device for collecting coarse powder after classification,
A classifying device comprising a return pipe for recirculating the dust-containing gas discharged from the cyclone to a supply section of the classifier and a suction fan disposed in the middle of the return pipe, the classifying device being an upright cylindrical shape. The casing is equipped with a raw powder supply pipe at the center of the top of the casing, a raw powder dispersion plate is fixedly mounted on the upper part of the casing, and a drive shaft consisting of a hollow pipe around which a plurality of classification blades are circumferentially provided is provided directly below the dispersion plate. A fine powder discharge port, which is rotatably supported on the central axis of the casing and discharges dust-containing air containing fine powder classified by the classification blade, is provided at the lower end of the hollow tube, and A donut-shaped horizontal disk is fixed on the inner peripheral side of the casing, and a plurality of stirring blades on the circumference are fixed on the hollow tube between the classification blade and the horizontal disk, facing the stirring blade. Coarse powder discharge pipe for discharging the coarse powder after classification is tangentially connected to the casing Was classified equipment configuration in which the inlet pipe of the air flowing converting said class blades of the lower casing.

[0006]

[Function] Raw powder is introduced from the supply pipe onto the dispersion plate, distributed evenly around the circumference, and falls into the classification chamber. Among the raw materials, fine powder is directed toward the classification blade by the suction force of the air stream flowing downward in the hollow tube, and fine powder below the classification point is discharged from the fine powder discharge port.
On the other hand, coarse powder above the classification point falls on a horizontal disc, or is hit by a stirring blade to separate the fine powder attached around the coarse powder, and the swirling airflow from the stirring blade causes the coarse powder to be discharged from the coarse powder discharge pipe. Coarse powder is discharged and enters the cyclone together with the air stream, and the dust particles discharged from the cyclone are sprayed again onto the dispersion plate through the return pipe, and the fine particles in the dust gas are classified again by the classification blade. Receive action.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment according to the present invention, FIG. 1 is a vertical cross-sectional view of a classifier, FIG. 2 is a plan view of the classifier, and FIG. 3 is an explanatory diagram showing the flow of powder in the classifier. FIG. 4 is a flow sheet of classification equipment. The solid arrows in the figure indicate the flow of air flow. As shown in FIG. 4, the classifying equipment 1 uses the classifier 2 to feed the coarse powder after the classification to the cyclone 2 through the feed pipe 100.
00 to collect the coarse powder, and return the collected dust-containing gas to the supply unit of the classification device 2 via the suction fan 300 and the return pipe 400, and the fine powder after classification by the suction force of the suction fan 700. Through the discharge pipe 500 to the bag filter 6
It is collected at 00.

On the other hand, as shown in FIG. 1, the classifier 2 has a raw powder supply pipe 1 at the top of the center of an upright cylindrical casing 2a.
In the classification chamber 2X immediately below the supply pipe 16, a hollow pipe (driving shaft) 3 is vertically supported by bearings 4 and 5 on the central axis of the device, and is attached to the lower part of the hollow pipe 3. V pulley 7a,
The variable speed electric motor 9 is configured to be rotationally driven via the V belt 8a and the V pulley 10a. The bearings 4 and 5 are fixed and held by a frame 6 supported by a support 6a. A conical dispersion plate 15 is fixedly mounted on the top of the hollow tube 3, and a plurality of scrapers 15a are vertically radiated radially around the circumference of the dispersion plate 15. A plurality of (three in the embodiment of FIG. 1) horizontal discs 11 are provided below the dispersion plate 15.
Are provided around the hollow tube 3 in multiple stages, and vertical classification blades 12 are equally distributed between the horizontal disks 11. Below the classifying blade 15, a donut-shaped horizontal disk 80 is fixedly mounted on the casing 2a.
A plurality of stirring blades 70 formed of vertical flat plates so as to sweep the upper surface of the horizontal disk 80 between
Is fixed to the hollow tube 3 and is configured to rotate integrally with the hollow tube 3. 1 of the peripheral surface of the casing 2a facing the stirring blade 70
As shown in FIG. 2, a coarse powder discharge pipe 60 is horizontally provided tangentially to the casing 2a at each location. Reference numeral 90 is a column base attached to the lower portion of the casing 2a. Support 6
A plurality of circumferentially-introduced pipes 50 for airflow rising from below the casing 2a toward the stirring blade 70 and the classification blade 12 are attached to a. The classification blade 12 may be radial in the radial direction, or may be a receding blade whose outer peripheral side recedes with respect to the rotation direction.

Next, the classification equipment 1 constructed as described above
Also, the operation of the classifying device 2 will be described. FIG. 3 shows the flow of powder and air in the classifying device 2. The raw powder (coarse powder and fine powder) dropped on the rotating dispersion plate 15 is evenly distributed around the circumference by centrifugal force, and the outer circumference of the dispersion plate 15 is shown. Free fall more. On the other hand, the classifying blade 12 and the stirring blade 70 are rotating integrally with the rotating hollow tube 3, and the airflow rising in the introducing pipe 50 is swirled by the stirring blade 70 while the airflow flowing into the classifying blade 12 is changed. It is always formed, and the coarse powder in the raw powder (indicated by white circles in FIG. 3) overcomes these air currents or is bounced off by the classification blade 12 and is sucked by the suction fan 300 located downstream. While being discharged from the coarse powder discharge pipe and sent to the cyclone 200, the fine powder in the raw powder is subjected to the classification action of the classification blade 12, and only the fine powder below the classification point descends with the inflow air in the hollow tube 3 and is sucked. The dust is discharged from the fine powder discharge port 20 by the suction force of the fan 700, and is collected by the dust collector (bag filter 600).
The fine powder adhering to the coarse powder is separated from the coarse powder when it is impacted by falling on the horizontal disk 80 or when hit by the stirring blade 70, so that the fine powder yield is further improved. The classification point is adjusted by controlling the number of revolutions of the hollow tube 3 or by controlling the amount of air downstream of the hollow pipe 3 and the amount of air flowing through the coarse powder discharge pipe 60. The coarse powder air-conveyed by the coarse powder discharge pipe 60 and the feed pipe 100 enters the cyclone 200 to collect the coarse powder, and the dust-containing gas containing the fine powder discharged from the cyclone 200 is sucked by the suction fan 300 and the return pipe. It is sent to the inside of the classification chamber 2X from the collecting pipe 400a of the classification device 2 via 400.

The classifier 2 used in the present invention is a system in which the fine powder after classification is guided to the lower part of the center of the device and the raw material powder is dropped from the upper part of the shaft center to the center of the dispersion plate. Moreover, the uniform dispersion is stable even when a large amount of raw powder is supplied. Therefore, as a result of performing a classification test of the raw powder using the talc powder in the classification equipment in which such a classification device is formed in a closed circuit, as compared with the classification result of only the classification device 2, the fine powder yield (based on the weight of the raw powder is The fine powder weight ratio) was improved by about 5 to 10%.

[0011]

In the classifying equipment of the present invention, the accuracy of classification is improved by using the classifying device for performing the center feed to disperse and homogenize the raw powder, and the closed circuit is formed to remove the coarse powder. Since the fine powder was collected, the fine powder yield is improved. Also, classification of high-concentration powder can be performed without any problems.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a classification device according to an embodiment of the present invention.

FIG. 2 is a plan view of a classification device according to an embodiment of the present invention.

FIG. 3 is a flow diagram of the classification device according to the embodiment of the present invention.

FIG. 4 is a flow sheet of a classification facility according to an example of the present invention.

[Explanation of symbols]

 1 Classification Equipment 2 Classification Apparatus 2a Casing 3 Hollow Tube 4 Bearing 5 Bearing 6 Stand 7a V Pulley 8a V Belt 9 Variable Speed Motor 10a V Pulley 11 Horizontal Disc 12 Classification Blade 15 Dispersion Plate 15a Scraper 16 Supply Pipe 16a Raw Material Collection Pipe 20 Fine powder discharge port 50 Inlet pipe 60 Coarse powder discharge pipe 70 Stirring blade 80 Horizontal disk 90 Column base 100 Feed pipe 200 Cyclone 300 Suction fan 400 Return pipe 400a Collecting pipe 500 Discharge pipe 600 Bag filter 700 Suction fan

Claims (1)

[Claims] 1. A classifier, a cyclone connected to the classifier for collecting coarse powder after classification, and a return pipe for recirculating dust-containing gas discharged from the cyclone to a supply section of the classifier. A classifying device comprising a suction fan disposed in the middle of the return pipe, the classifying device having a raw powder supply pipe at the top center of an upright cylindrical casing and a raw powder dispersion plate at the top. A drive shaft composed of a hollow tube having a plurality of classification blades circumferentially provided around the dispersion plate is rotatably supported on the central axis of the casing, and fine powder classified by the classification blades is A fine powder discharge port for discharging contained dust-containing air is provided at the lower end of the hollow tube, and a donut-shaped horizontal disc is fixedly provided on the inner peripheral side of the casing below the classification blade, and the classification blade and the horizontal circle are fixed. A plurality of circumferential stirring blades are fixedly installed in the hollow tube between the plate and the stirring blades. A coarse powder discharge pipe that discharges the coarse powder after classification is tangentially connected to the casing opposite to the casing, and the casing below the horizontal disk is provided with an inlet pipe for the air flowing into the classification blade. Facility.