JPH06269738A - Classifying equipment - Google Patents

Abstract

PURPOSE:To provide a classifying device excellent in fine particle yield and of low installation cost and where the classifying accuracy is maintained even for powder of high concentration. CONSTITUTION:Classifying equipment comprises a classifier 2, a collector and a suction fan for carrying and collecting fine particles after classification, a cyclone for collecting coarse particles connected to the classifier 2 and a return pipe for recirculating the exhaust from the cyclone to the raw material feeding part of the classifier 2. In the classifier 2, a vertical cylindrical casing 2a is provided with a feeding pipe 16, and a hollow pipe 3 to which a disperse plate 15 is fixed in the upper part and to which a classifying blade 12 is circumferentially fitted immediately below the dispersion plate 15 is pivotally and freely rotatably supported on the center axis of the casing 2a. A discharge port 20 for discharging fine particle contg. air is installed at the lower end of the hollow pipe 3, and a horizontal disc 80 is installed on the inner peripheral side of the casing below the classifying blade 12, and also plural agitating blades 70 are circumferentially installed above it.

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 powder particles crushed by a crusher into a product with a required particle size by an air stream, and to classify them into products. Centrifugal force classification, which is roughly classified into classification and centrifugal force classification, and 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, the performance of classifiers has become more sophisticated, and finer 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]

[Means for Solving the Problems] Therefore, as a means for solving the above problems and exhibiting better performance, the classifying equipment of the present invention has a classifying device and a fine powder after classification which is connected to the classifying device. A collecting device for collecting, a suction fan following the collecting device, a cyclone connected to the classifying device for collecting the coarse powder after classification, and a dust-containing gas discharged from the cyclone of the classifying device. A classifying device comprising a return pipe for recirculating to a supply section, wherein the classifying device is provided with a raw powder supply pipe at the center of the top of an upright cylindrical casing, and a raw powder dispersion plate is fixedly provided on the upper part of the casing. A drive shaft composed of a hollow tube around which a plurality of classification blades are provided directly below the dispersion plate is rotatably supported on the central axis of the casing, and contains a fine powder classified by the classification blades. A fine powder discharge port for discharging dust air is provided at the lower end of the hollow pipe, A donut-shaped horizontal disc is fixedly provided on the inner peripheral side of the casing below the classification blade, and a coarse powder discharge pipe for discharging the coarse powder after classification is tangentially connected to the casing facing the stirring blade. This is a classification facility in which a casing below the horizontal disk is provided with an inlet pipe for air that flows into the classification blade.

[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 flow, and the dust-containing gas discharged from the cyclone is sprayed again onto the dispersion plate through the return pipe, and the fine powder in the dust-containing gas is again classified by the classification blade. Receive action. The fine powder discharged from the fine powder outlet is collected by a collection device such as a bag filter, and the carrier air after collection passes through a suction fan and is discharged to the atmosphere.

[0007]

DETAILED 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 classifying device 2 via the electromagnetic on-off valve 300 and the return pipe 400, and the suction fan 700 sucks the classified gas. The fine powder passes through the discharge pipe 500 and the bag filter 6
It is collected at 00. The suction ventilation volume is adjusted by the solenoid opening / closing valve 800, and the circulation air volume of the return pipe is adjusted by the solenoid opening / closing valve 300.

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 inlet 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 circumferentially by centrifugal force and the outer periphery 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 tube 50 is swirled by the stirring blade 70 while the airflow flowing into the classifying blade 12 is changed. Coarse powder in the raw powder (indicated by white circles in FIG. 3) that is always formed overcomes these air currents or is bounced off by the classification blade 12 and is fed by the suction force of the suction fan 700. 100 and return pipe 4
By the suction force generated in the loop formed by 00, it is discharged from the coarse powder discharge pipe and sent to the cyclone 200 downstream, and the fine powder in the raw powder is subjected to the classification action of the classification blade 12,
Only the fine powder below the classification point descends in the hollow tube 3 together with the inflowing air, and is discharged from the fine powder discharge port 20 by the suction force of the suction fan 700, and is a collecting device (bag filter 600).
Captured in. Ventilation amount of suction fan 700 and feed pipe 10
0 and the circulating air volume of the return pipe 400 are adjusted by the damper opening degree of the electromagnetic opening / closing valve 800 and the electromagnetic opening / closing valve 300, respectively. 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-transported by the coarse powder discharge pipe 60 and the feed pipe 100 is the cyclone 20.
Cyclone 200 as the coarse powder was collected
The dust-containing gas containing the fine powder discharged from the solenoid valve 30
0 and the return pipe 400, and the collecting pipe 4 of the classification device 2
It is sent to the classification room 2X from 00a.

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%. Further, in the classification system of the present invention, as shown in FIG. 4, fine dust-containing air is used without using a suction fan in the circulation lines of the return pipe and the feed pipe for recovering coarse powder from the dust-containing air containing coarse powder. Since the suction force of the suction fan after the collection device that collects finer powder can be used, the equipment cost is lower and the maintainability is also improved.

[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. Furthermore, since the fine powder suction line and the coarse powder suction circulation line can be completed with a single suction fan, the equipment cost is low and the maintainability is improved.

[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 device 2a casing 3 hollow tube 4 bearing 5 bearing 6 stand 7a V pulley 8a V belt 9 variable speed electric motor 10a V pulley 11 horizontal disc 12 classification blade 15 dispersion plate 15a scraper 16 supply Pipe 16a Raw material collecting pipe 20 Fine powder discharge port 50 Introducing pipe 60 Coarse powder discharging pipe 70 Stirring blade 80 Horizontal disc 90 Column base 100 Feed pipe 200 Cyclone 300 Electromagnetic on-off valve 400 Return pipe 400a Collecting pipe 500 Discharge pipe 600 Bag filter 700 Suction Fan 800 solenoid valve

Claims (1)

[Claims] 1. A classifying device, a collecting device connected to the classifying device for collecting the fine powder after classification, a suction fan following the collecting device, and a coarse powder after classification connected to the classifying device. And a return pipe for recirculating the dust-containing gas discharged from the cyclone to the supply section of the classifier, the classifier being the center of the top of an upright cylindrical casing. The raw powder supply pipe is provided in the upper part of the casing, the raw powder dispersion plate is fixed on the upper part, and the drive shaft consisting of a hollow pipe around which a plurality of classification blades are circumferentially provided directly below the dispersion plate is used as the central axis of the casing. A pulverized air outlet rotatably supported on the upper side is provided at the lower end of the hollow tube for discharging dust-containing air containing fine powder classified by the classifying blade, and at the inner peripheral side of the casing below the classifying blade. A donut-shaped horizontal disk is fixed and the casing is opposed to the stirring blade. A classifying equipment having a structure in which a coarse powder discharge pipe for discharging coarse powder after classification is tangentially connected to a group, and an air introduction pipe for air flowing into the classification blade is provided in a casing below the horizontal disk.