SU1284604A1 - Pneumatic classifier - Google Patents

Description

The invention relates to agricultural machinery, in particular, devices for the separation of bulk materials, such as seeds of agricultural crops, into fractions according to yields.

The purpose of the invention is to improve the classification efficiency by optimizing the mode of feeding the material into the columns.

FIG. 1 shows the proposed device, a general view; in fig. 2 is a section A-A in FIG. one.

The pneumatic classifier contains a loading device 1 with a feeder (not shown), a series of aspiration columns 2-6. At the top, each suction column passes into a jigging chamber 7, the cross sectional area of which is much larger than the cross sectional area of the suction column itself. The depository chambers of all the columns through the pipes 8 are connected to a common pneumatic collector 9 connected to the suction mouth of the fan 10 of the aspiration system. Inside each chamber 7 there is a device for adjusting the speed of air flow in the suction column. It contains a valve 11 mounted on a screw rod 12, moved along its axis by means of a handwheel 13. When screwing in the rod 12, the gap between the valve and the nozzle 8 is reduced. As a result, the amount of air sucked through the annular hole between these elements and, consequently, the speed is reduced air flow in the suction column. When unscrewing the rod 12, on the contrary, the air flow rate in the suction column increases.

Each jigging chamber 7 is provided with a device 14 for discharging material entering through an aspiration column.

In the transition zone of the aspiration column, a visor 15 is installed in the jigging chamber above the column in order to prevent light fractions from entering the exhaust pneumatic collector 9.

Each aspiration column is designed as a tube or prism. From below it is open, and through this end the air enters it. Slightly higher than the lower end in one of the walls of the column, a loading window was made to enter the separated material into it.

Aspiration columns are installed so that their lower parts are arranged in steps, forming a cascade. Under each column there is a sequential transport unit for the material, which is a package of pitched trays 16–18 located at different levels in height. Tray 16 covers the entire end section of the suction column. The remaining trays are

ds inside the tray 16 and are offset from it so that the upper section of the suction column divides the cross section of the suction column into parts. The number of trays in the block may be two or more, depending on the cross-section of the suction column, the required quality of material separation. The trays have different angles of inclination to the horizon, but they are all connected to the boot window of the next column.

The sloping surface of each tray in the area adjacent to the loading window of the next column has a small horizontal section or even bent up at an angle of 45 ° to prevent the kinetic energy of particles rolling along the inclined plane of the tray from affecting the material separation process. Under the last column is installed pallet 19.

The device works as follows.

Bulk material to be divided into fractions by windage is loaded into the device 1. Then the fan 10 is turned on and the required air flow rate is set in each suction column. This is done by rotating the handwheel 13 in one direction or another.

In the suction column 2, which is the first in a line in the process line, the smallest speed is set to correspond to the extraction of the fraction of material with the highest sail. And in subsequent columns, successively increasing airflow rates are set at a certain interval.

Then, by turning on the feeder in the hopper, column 2 is loaded continuously. Inside this column, a fraction of the material with the highest windage is extracted with an air stream.

The remaining material under the action of gravitational forces is lowered down and along the sloping device, consisting of trays 16-18, is directed into the loading window of the next column, in which the same separation process takes place, with the only difference that the air flow rate in this column is greater and, consequently, material with less sail yields than in the previous column. Similarly, the material passes through all the suction columns, and in each of them it is divided into two fractions. The very fraction of the material with the lowest windage is poured into the tray 19.

The material lifted by the air flow enters the jigging chamber 7, where due to a sharp increase in the cross-sectional area and, respectively.

by decreasing the air flow rate, it precipitates at the bottom and is outputted by a special device 14.

The process of unloading the separated material can be carried out both continuously and periodically.

If coarse separation of the material into fractions is allowed, it is possible to exclude part of the columns from the process by completely closing the end hole in the corresponding nozzle 8.

Installing the bottom of the pitched trays at an angle to the horizon from 0 to 45 ° improves the separation efficiency. This is due to the fact that the particle rolling down the ramp surface of the tray acquires a certain speed with which it enters the aspiration channel. If the vector of the absolute velocity of a particle has a vertical component directed downward, then the aerodynamic forces must overcome the inertia force of the particle at some site. In this case, the separation area is located in the lower part of the suction column, which is undesirable for two reasons: the uniformity of the air flow over the channel section in this zone is much worse than in the upper part, therefore, the clarity (quality) of the separation is deteriorated, in addition, for to improve the quality of separation, it is necessary to increase the length of the bottom of the channel, i.e. increase the size of the device.

The effect of this phenomenon can be reduced if the vertical component of the Moc / A-D

0

s

five

0

0

to increase the particle size to zero. If the component under consideration is directed upwards, then one can count on the achievement of two positive effects; the separation area is shifted upward to the zone of the most equalized air flow, thereby improving the quality of separation; in addition, the particle has the ability (in accordance with the law of ballistics) to move as far as possible towards the opposite wall of the channel. Since the length of the sloped surfaces of the chutes is different, the speed of the particles converging from it is different. Therefore, the angle of the bend of the areas adjacent to the loading window of the subsequent channel must be different and be in the range from zero (for low rates of descent) to 45 °, providing the greatest range of the particle.

The pneumatic classifier with suction columns, which have consistently decreasing cross-sectional areas, is made with regard to the gradual decrease in the amount of material from one column to another. Such a solution allows the development of an economically efficient pneumo classifier in terms of energy consumption.

The proposed pneumatic classifier allows high quality simultaneous separation of bulk materials into a series of windage fractions. It can, for example, be effectively used in the process of improving the sowing qualities of seeds.

Claims (2)

1. PNEUMATIC CLASSIFICATOR, including cascade-mounted suction columns with loading windows, units of sequential transportation of material from one suction column to another, communicating the lower part of the previous suction column with a loading window subsequent, air separation system, loading device of the source material, collections of finished fractions, characterized in that, in order to increase the classification efficiency by optimizing the flow of material into each suction column, each the unit for sequential transportation of material from one suction column to another is made in the form of a package of pitched trays located one above the other, installed under the lower end of the corresponding suction column with a gap relative to it, while the cross section of the lower end of the suction column is blocked by the lower tray, and the upper trays' are offset relative to the lower cross-section of the suction column and are installed with their lower ends in the loading window of the underlying aspiration column, while the lower end The end of each tray in the loading window is bent to the longitudinal axis of the suction column at an angle of 90-45 °. 2. Pneumatic classifier according to π. 1, characterized in that the cross-sectional area of the suction columns is reduced from upper to lower. FIG. 1 SU. „, 1284604