SU1731297A1 - Pneumatic classifier - Google Patents

Abstract

This invention relates to the separation of bulk materials. The invention consists in the separation of materials on perforated surfaces. The device includes a housing 1 with a grate 2, a loading nozzle 6, a discharge nozzle 7 3 or

Description

The invention relates to pneumoclassification of various powdered materials, and more specifically to classification in multi-column classifiers, and can be applied in the chemical and mining industries, powder metallurgy, in mineral processing and other industries.

A classifier is known that includes a body in the form of a set of vertical separation columns with pouring devices installed in them, having a bottom in the form of an inclined separation grid, loading and unloading pipes, a device for supplying air and discharging a dust-air mixture. The disadvantage of this classifier is low classification efficiency due to the impossibility of cleaning the small product.

Closest to the proposed classifier, which includes a case in the form of a set of vertical separation columns with pouring devices installed in them, the upper ends of which are connected to a fine product cleaning device, a horizontal shaft with fixed impellers installed in it and having a bottom in the form inclined separation grid loading and unloading nozzles

The disadvantage of this classifier is increased energy costs for classification, caused by the high costs of aerodynamic pressure to impart rotational motion to the dust-air mixture after it passes fixed impellers.

The purpose of the invention is to reduce energy costs for classification by creating a device for cleaning up a small product with a small aerodynamic drag.

Reduction of energy costs for classification is achieved by the fact that in the classifier, including a hollow body with a bottom in the form of an inclined separation grid, inside which are placed vertical partitions with pouring devices, forming separation channels that transfer in the upper part into the device of cleaning the small

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the product, loading and unloading nozzles, devices for supplying air and removing the dust-air mixture; the device for cleaning the fine product is made in the form of a duct installed obliquely in the direction of inclination of the separation grid. Losses of aerodynamic pressure in a hollow box are insignificant, since they are caused only by air friction against the walls of the box.

FIG. 1 shows a pneumatic classifier; in fig. 2 shows a diagram of the operation of the fine product cleaning device; in fig. 3 is a diagram of the connection of a pneumatic classifier with a cyclone, a filter and a fan.

The pneumatic classifier consists of a hollow body 1 with a bottom in the form of an inclined separating grid 2, inside which there are vertical partitions 3 with pouring devices 4, forming separation channels, passing in the upper part into the device 5 for cleaning the small product, loading nozzle 6, discharge nozzle 7, the air intake devices 8 and the dust-air mixture removal device 9.

Classifier works as follows. With the start of the fan 10, air flow is circulated through the installation. With the help of the gates 11, the necessary total air flow through the classifier is established. The boundary grain is controlled by varying the air velocity in the separation columns. The source material is fed from the hopper 12 by the feeder 13 through the pipe 6 to the separation grid 2 under the first separation column. There, the material comes in a fluidized state, is blown through the air stream and enters the first separation column through its lower section. The classification of the material takes place in the column. The coarse particles descend back to the grate and move under the slope in a fluidized state, continuously striking until they reach the next separation column. The coarse product is scrubbed in all the columns and removed through pipe 7 from the classifier to the hopper 14 of the coarse product. Particles of the fine product emerge from the columns through their upper sections in

inclined Biv duct oblique airflow is classified by gravity and vertical component forces of air pressure on particles. At the same time, the particles move in the direction of the duct tilt under the action of the horizontal component forces of air pressure on the particles. Therefore, the non-dusty part of the small product does not settle

into the separation columns from which it came out, and into the subsequent ones along the course of the horizontal transfer of particles. There is a transfer of particles from the column to the column in the direction of tilt of the box, i.e. against the direction in which the coarse product is moving along the separation grid. Some of the particles are deposited on the sloping wall of the duct and poured along it into the first column. Therefore, when classifying a particular material, the walls of the box should be inclined at an angle not greater than the angle of repose of this material. Dust is removed from the inclined duct through the device 10 for removing the dust-air mixture with the air flow to the cyclone 15. Dust not precipitated by the cyclone is trapped by the filter 16. After the filter, air enters the suction inlet of the fan. In this installation, the classification is carried out by a circulating air flow. Excess air (about 10%) is discharged into the atmosphere by suction on the highway. The unit works under vacuum, which eliminates dust emission into the environment.

Claims (1)

Claims of the invention: Pneumatic classifier, including a body with a bottom in the form of an inclined separating grid, vertical partitions above the grille with pouring devices, forming separation channels, fine product cleaning device and dust-air mixture outlet pipe located in the upper part of the body, loading and unloading branch pipes and air inlet located in the lower part of the body, differing from that, in order to reduce energy intensity of the classifier, the cleaning device is made in the form of a box, installed obliquely in the direction of inclination of the separation grid. Air and shallow 7T 7lWkyT 7K / N 7 j4 Large / st FIG. 2 tfcsodf Dezduh 1 Air Material ъ z N Ј