SU1450886A1 - Classifier of loose materials - Google Patents

Abstract

This invention relates to a technique for the classification of bulk materials in a dry form, and may be. used in the purification of grain and its products in the milling industry, feed milling industry, and other fields. The purpose of the invention is to improve the quality of classification and increase operational reliability by eliminating the seizure of particles in the openings of the sieves () and ensuring the conditions

Description

one

The invention relates to the technique of classification of bulk materials according to the size of their constituent particles in a dry form and can be used in the purification of grain and its products in agriculture, flour milling, and feed industry, as well as in coal, mining, building materials. and in other areas.

The purpose of the invention is to improve the quality of classification and increase reliability in operation by eliminating the seizure of particles in the openings of the sieves and ensuring that the particles are free from the separating surface of the sieves.

Fig, 1 shows a longitudinal section of the classifier; in FIG. 2, a screening of the sieve, side view and from above.

The classifier includes a housing 1, which is a vertical plate, a loading device 2 with a flap 3, inclined screening screens 4, deflectors 5 and discharge pipes 6 and 7 for outputting the separated fractions.

The loading device 2 is equipped with an adjustable damper 3, by changing the position of which you can set the classifier's required capacity. In case 1, under each screening sieve 4 there are deflectors 5, with the help of which the small fraction, inserted through sieve 4, is directed to the windows

A, carved in the front and rear walls of the body of the classifier.

The sieves are made with Pdelite holes, with an increasing size of the slit in the direction of movement of the material, which creates favorable conditions for sifting small particles of various sizes in the wedge-shaped holes where their width slightly exceeds the size of particles

However, in order to eliminate sticking of the product particles in the wedge-shaped holes, it is necessary that they move at a certain speed and at the same time experience a pushing action from the side behind the reaching particles. In this case, the component of the force of gravity of each particle, directed perpendicularly to the plane of the wedge-shaped hole, should be sufficient to change the direction.

3

particle velocity and select it over the hole. The fulfillment of these conditions is achieved only if the wedge-shaped angle of the hole is associated with the reptet angle of inclination with the dependence 0.009 0, A14 ctgo, and the angle o is chosen taking into account the natural angle, v bulk material from the ratio of 0.9 tg.itgal. 1, 4 tg.

Fulfillment of these conditions ensures the necessary speed of product movement along the 4th ram (P, 8 - 1, 2 m / s) and prevents the product particles from getting stuck in the wedge-shaped holes, due to which the classifier provides high performance and separation efficiency.

As the product passes from one sieve to another, the content of the fine fraction in it decreases, resulting in a decrease in the angle of repose of the product. The marked decrease in the angle of repose is especially noticeable when a significant amount of the fines fraction (5% and more) is contained in the starting product. Investigator

but, in order to fulfill this condition, in this case each successive sieve must be installed at a smaller angle to the horizon in comparison with the previous one. In particular, as shown in FIG. 1 classifier condition

s, 7 0

 l, -7 with (.

Successful operation of the classifier is possible only if the particles of the product will freely descend from the sieves 4. With a small amount of particles in the initial product, the size of which is commensurate with the width of the wedge-shaped holes in their final part, the screening surfaces of the sieves can be flat. If the number of such particles is higher than 2%, then for their free exit from the sieve, the wedge-shaped holes should have expanding areas at their lower ends, and the ends of the sieves 4 should be bent down so that the bend line runs perpendicular to the longitudinal axis of the wedge-shaped holes through their expanding sites.

Classifier works as follows.

The bulk material flows from the loading device 2 to the first sieve 4. Since there are no cross bars throughout the sieve 4 sieve surface, the product, under the action of the component gravity force directed along the wedge-shaped holes, steadily moves towards the exit end of the sieve. With this movement, the particles of the fine fraction under the action of a component of gravity, perpendicular to the screening surface, penetrate through the wedge-shaped holes and then enter the deflector 5, with the help of which they are guided through the outlet port in the housing 1 to the outlet 6 for output small fraction.

five

The coarse fraction and particles of the small 5 fraction, which did not stand out on

0

five

0

five

the first sieve 4 is fed to the second sieve where the described process is repeated. The number of sieve 4 is determined by the ultimate goal of the classification and the particle size distribution of the original product. The closer the maximum and peace particle sizes in the fine fraction, the larger the sieves should be.

The components of the fine fraction released on all the screening surfaces of the sieves are combined and removed from the classifier through nozzles 6. The coarse fraction comes off the last sieve and is withdrawn from the classifier through nozzle 7.

C and b angles can be assigned at specified intervals. The optimal values of these angles correspond to the midpoints of the intervals.

Higher angles d are selected for the upper sieves of those classifiers that are designed to separate products containing a significant amount (50% or more) of the fine component.

For example, grain milling products in the feed industry contain over 60% of the fines and have an angle of repose equal to about 38. Consequently, the angle.

"Must be determined from the dependence of tg with / (0.9 - l, 4) tg. Г8 °

fm.g

Claims (2)

Claim 1. A classifier of bulk materials, including inclined sieving 1450886 6 sieves installed zigzag one below the other, a loading device and nozzles for 5 output of separated fractions, characterized in that, in order to improve the quality of classification and increase reliability in operation by eliminating jamming of particles 10 in the openings of the sieves and to ensure the conditions for the free flow of particles from the separating surface of the sieves, the holes of the sieving sieves are made slotted with an increasing size of 15 slits in the direction of movement Nia material, the angle of inclination and the angle of lattice d wedging holes β are related by 0.009 ctg d / tgfJ ^ 0.014 ctg d 2. The classifier according to claim 1, wherein the angle of inclination of each previous sieve is greater than the next. 25 3. The classifier according to claim 1, characterized in that the openings of the sieves at their lower ends have expanding sections, and the ends of the sieves are bent downward, while the line 30, the bending of these ends extends perpendicular to the longitudinal axes of the wedge-shaped openings through their expanding portions.