RU2203150C2 - Apparatus for sorting finely dispersed materials - Google Patents

Abstract

FIELD: separation of finely dispersed materials by fraction sizes, concentration of minerals in metallurgical, chemical and food industry branches. SUBSTANCE: apparatus for sorting finely dispersed materials includes sorting chamber with arc-shaped sieving surface; vanes arranged along shaft mounted with possibility of rotation; branch pipes for discharging sorted products. Apparatus is also provided with feeding branch pipe for loading material in the form of aerated suspension. Splitters are arranged on end portions of blades. One side of splitters is turned in vane rotation direction and it is bent towards sieving surface. Vanes are mounted with possibility of rotation at frequency 50 -200 Hz and with possibility of regulating spacing between splitters and sieving surface. EFFECT: enhanced efficiency of sorting, especially of finely dispersed materials. 1 dwg, 1 tbl

Description

 The invention relates to the separation by size of finely dispersed materials and can be used in mineral processing, as well as in the metallurgical, chemical and food industries.

For separating dispersed materials by size, devices using a stationary spherical screening surface are known, inside which blades are radially mounted on a rotating shaft or rotor to maintain the suspension and transport the starting material to the screening surface, as well as to clean the latter. Moreover, the blades have a different shape and the order of their placement:
- pairwise fastening of straight blades on the rotor shaft with the offset of each pair of blades 90 ^° relative to each other and the angle of attack of the blades within minus 10 ^o to plus 40 ^o (see ed. St. 463479, 07 V 1/24, Drum Rotor roar 10, B.I. 1975),
- curved blades placed on the impeller, which is rigidly connected to the rotor blade mounted on a rotating shaft (see ed. St. 839604, 07 1/24, Drum Roar, B.I. 23, 1981),
- blades with curved ends towards the screening surface, and the bent part of the blades is located at an angle to the longitudinal axis of the rotor (see ed. St. 1404124, B 07 V 1/24, Drum Roar, B.I. 23, 1988).

 A common drawback of these design solutions is the low particle size separation efficiency of especially finely dispersed materials due to clogging of the screening surface by large particles, which are concentrated on the screening surface by the action of centrifugal forces.

To prevent clogging of the screening surface by large particles, devices are known in which:
- brushes are installed on the rotating rotor with the possibility of reciprocating radial movement when they come into contact with a vibrating screening surface (see ed. St. 1419753, 07/01/08, Device for sieving materials, B.I. 32, 1988);
- the rotating spherical surface is equipped with a shaker and is located eccentrically relative to the rotor, on which brushes with spring shock absorbers are installed (see ed. ;
- the working edges of the rectilinear rotor blades facing the screening surface are rounded (see ed. St. 1613200, 07 V 1/20, Device for sieving bulk materials, B.I. 46, 1990).

 These technical solutions, although they can improve the classification efficiency due to mechanical cleaning of the screening surface, but lead to its rapid wear.

 The closest in technical essence to the proposed invention is a classifier of bulk materials, including an arc sifting surface, on the outside of which a casing is installed, and inside - a rotating drum, on which casting blades and cleaners are alternately installed (see ed. St. 897315, B 07 V 1/20, 01/15/1982 (prototype)).

 The disadvantage of this classifier is low productivity due to the small gap between the rotating drum and the screening surface, low classification efficiency due to the inability to remove particles having a close size with the screening hole from the screening surface, as well as the large wear of the latter as a result of the movement of cleaners along it .

 The aim of the present invention is to improve the classification efficiency and productivity of the device, especially when separating finely dispersed materials.

 This goal was achieved in that a device for classifying finely dispersed materials, comprising a sorting chamber with an arc sifting surface, blades placed along a shaft mounted for rotation, pipes for outputting classification products, according to the invention is equipped with a pipe for supplying material in the form of aerosuspension, and on at the ends of the blades mounted dividers, one of the sides of which, facing in the direction of rotation of the blades, is curved to the screening surface, while the blades are installed They are rotatable with a frequency of 50 to 200 Hz and with the ability to control the distance between the dividers and the screening surface.

 The novelty of the proposed technical solution lies in the fact that the installation at the ends of the blades of dividers, one of the sides of which, facing in the direction of rotation, is curved to the screening surface.

 This ensures that behind the rotating blades the emergence of turbulent (vortex) flows near the screening surface. In a turbulent flow of aerosuspension due to a local change in the magnitude and direction of pressure and speed, the material is stratified by size near the screening surface, which increases the efficiency and productivity of the separation process.

 A device for classifying finely dispersed materials (see drawing) consists of a housing 1, inside of which an arc screening surface 3 is installed on the frame 2; rectilinear blades 4, mounted along the shaft 5, made with the possibility of rotation. At the free ends of the blades 4 mounted dividers 6, the sides of which, facing in the direction of rotation of the blades, are curved to the screening surface. The device is equipped with nozzles for supplying the initial aerosuspension 7, the output of the under-sieve product 8 and the over-sieve product 9. To regulate the pressure in the working area and the number of out-sizing products, the nozzle 9 is equipped with a gate 10.

 The device operates as follows. The source material in the form of aerosuspension through the nozzle 7 under pressure is fed into the inside of the device, where under the action of centrifugal flows created by the rotating blades 4, the material moves to the screening surface 3, through which it is divided by size. In this case, the dividers 6 with a curved side to the screening surface in the direction of rotation of the blades create a disruptive nature of the flow around the suspension. As a result of this, a pronounced turbulent character of the flow of aerosuspension arises behind the blades in the form of vortex flows that move along the screening surface at a speed equal to the speed of rotation of the blades. The dimensions and frequency of turbulent disturbances depend on the angle of inclination of the dividers, the distance between them and the screening surface, as well as on the number of blades and their speed of rotation.

 Due to the pressure drop in the vortex region, large particles, as having a large mass, as well as particles having a large windage, are primarily involved from the screening surface. As a result of this, the screening surface is cleaned of large particles, and due to the pressure drop in the working chamber and in the unloading zone of the under-sieve product, the passage of small particles through the screening surface is accelerated. In this case, large particles are mainly in suspension and do not have a significant abrasive effect on the screening surface, and their discharge from the working area is carried out through the pipe 9 and is regulated by the gate 10.

 The separation efficiency depending on the size of the starting material and the requirements for the composition of the classification products can be controlled by changing the distance between the dividers and the screening surface, the pressure in the working area, the turbulence frequency created by the rotating blades, from 50 to 200 Hz. With a decrease in the particle size in the allocated sublattice product, an increase in the frequency of turbulence is required, which is achieved by increasing the speed of rotation of the blades. Moreover, the separation of the material in centrifugal-turbulent flows in the proposed device occurs by particle size, having a size of 8-12 times smaller than the holes of the screening surface. For example, with openings of a sifting surface of 315 μm and a turbulence frequency of 100 Hz, the sublattice product contains 97% of particles with a particle size of less than 40 μm, and with openings of a sieving surface of 120 μm and a turbulence frequency of 200 Hz, the sublattice product contains 95% of particles with a particle size of less than 10 μm.

 From the table of comparative indicators of the separation of phlogopite powder, it follows that, compared with the prototype (a.s. 897315), the proposed device increases the classification efficiency by class - 10 μm by 20%, increases the service life of the screening surface by 4 times and productivity by 3 times .

Claims (1)

 A device for classifying finely dispersed materials, comprising a sorting chamber with an arc sieving surface, blades placed along a shaft mounted for rotation, nozzles for outputting classification products, characterized in that it is equipped with a nozzle for supplying material in the form of aerosuspension, dividers are installed at the ends of the blades , one of the sides of which, facing in the direction of rotation of the blades, is curved to the screening surface, while the blades are mounted for rotation with pilots at from 50 to 200 Hz and with the possibility of adjusting the distance between the screening surface and dividers.

Images