SU865432A2 - Air classifier - Google Patents

Description

(54) AIR CLASSIFIER

I

The invention relates to devices for the industrial processing of grain, and more particularly to devices for separating heavy mineral impurities from the grain.

According to the main author. St. No. 386685 is well known for an air classifier, comprising a body made of a breathable partition in the form of a louvered grille, selectors with an adjustable slot for exhaust fractions and an adjustable side slot with an air visor, loading and unloading devices 1.

The disadvantages of the known device are the low efficiency of separation of the heavy fraction in it from the main mass, as well as the release into the similar fraction of a significant part of the passage fraction and the poor quality of classification.

The purpose of the invention is to increase the quality of classification.

The goal is achieved by the fact that the air classifier is equipped with an additional air-permeable partition made in the form of a louvered grille with selectors of fractions and branch pipes for supplying and discharging air, with springboard thresholds mounted on plates with slits of a louvered grille at a distance equal to half of its width , and nozzles located in the selectors of fractions.

The drawing shows the proposed classifier.

The air classifier consists of the main 1 and control 2 aerodynamic conveyors consisting of the same structural elements, with the control conveyor located under or inside the main aerodynamic conveyor and has

10 fluidized bed material width of the working channel, preferably 4-5 times.

Each of the conveyors consists of a lower 3 air supply and an upper one. With 4 air exhaust ducts, between which there is an air distribution grill 5, made of steel plates laid in the form of a louver. Part of the plates 6 of both conveyors, located under the funnels 7 for trapping heavy impurities, is made with adjustable

20 by means of a screw device 8 by a horizontal slot-slot 9 within such limits that its width would be 1.5 -

2 times the thickness of the particles of mineral impurities. Funnels 7 are provided with nozzles 10 for leveling the airflow velocity field and a side slit 12 adjustable by means of a screw device 11 for supplying air through the funnels to an adjustable horizontal slot-slit 9. Funnels 7 are connected to the control aerodynamic conveyor 13 via nozzles 13.

The first plate with an adjustable horizontal slot-slot of the main conveyor is installed at a distance at which the process of fluidization and sedimentation of a heavy mineral admixture has already finished (at least 400-500 mm from the feed zone of the split mixture), and subsequent plates with a horizontal slot-slot in increments of 200-250 mm, set at a distance within which the nature of the movement of the material becomes stationary again. On plates 6 with adjustable horizontal slits, the slits 9 of both conveyors, thresholds 14 are set before the slits, the height of which is selected depending on the conveyor's performance, and the distance from the threshold of the springboard to the horizontal slit-slit is about half the width this gap.

The device works as follows.

In the lower part of the main 1 and control 2 conveyors, high air pressure is fed from the fan through the air duct 3. The source material containing mineral impurities is fed to the upper part of the main conveyor 1 on the air distribution grille 5. Air, a passage through the louver air distribution grille, fluidizes the material and simultaneously moves it towards the exit from the conveyor. At a distance of 400-500 mm from the feed zone of the material, the latter is completely liquefied, and the heavy mineral impurity is lowered onto the grid and continues to move along it. Upon reaching the threshold of springboard 14, the material begins to move along a curved path. This is also facilitated by the stream of air escaping through the side adjustable slots 12. In these zones heavy mineral impurity

moves along steeper trajectories, and, overcoming the resistance of the air flow, passes and is sent to the control conveyor 2. The latter is necessary, since, together with heavy mineral impurities, a small amount of basic material also falls into the gathering.

The main mass of the grain passes over the gap along more gentle trajectories and continues along the conveyor further. Since it is not possible to isolate the entire mineral impurity in one exposure, the separation operation is repeated on subsequent similar funnels.

In the first funnels, heavy and large impurities are released, in the subsequent ones, smaller and lighter ones.

Thus, there is a separation of the source material into fractions, carried out along the way in the process of moving grain along an aerodynamic conveyor.

Claims (1)

Invention Formula Air classifier auth. St. No. 386685, characterized in that, in order to improve the quality of the classification, the air classifier is provided with an additional air-permeable partition made in the form of a louvered grille with selectors of fractions and nozzles for supplying and discharging air, springboards, installed on the plates with crevices the distance to the slit equal to half its width, and the nozzles located in the selectors of the fractions. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 386685, cl. In 07 In 4/08, 1971 (prototype).