SU1562023A1 - Vibrosieve - Google Patents

Abstract

The invention relates to the technique of separation and classification of bulk substances, intended for the separation of explosive electrifying dispersed materials and can be used in the chemical, pharmaceutical and other industries. The purpose of the invention is to increase the efficiency of separation of materials and reduce the explosion and fire hazard of the separation process. A grid 3 connected to the vibrodrive 2 of the grounded sieve bed 1 is fixed by means of insulators 8 and a grid 4 of separate sections 9 located under it. Vertical guides 5 are installed between grid 3 and grid 4 to form separate chambers 6 for accommodating the cut bodies 7 of elastic electrically conductive material. Within each chamber 6, the individual portions of the grid 4 are located at an angle to the grid 3. The size of the chopping bodies 7 is less than the distance between the grid 3 and the upper edge of the grid 4 on each section 9. The base 1 performs reciprocating movements in the plane of the grid 3. Partitioned the dispersed material is fed to the grid 3. The chops of the body 7 under the action of vibration make elastic displacements within the sections 9, deforming the grid 3 and the grid 4. Removing the charge from the grid 3 is achieved using the chopping bodies 7 of electrically conductive material. The bodies 7 transfer the charge from the grid 3 to the lattice 4. The amount of the transferred charge is insufficient to initiate an explosion of a dusty air mixture of particles of the dispersed material. Due to the fact that the size of the bodies 7 is less than the distance between the grid 3 and the upper edge of the grid 4, direct contact of the grid 3 with the grid 4 through the bodies 7 does not occur, which ensures the absence of powerful spark discharges. The guides 5 on the grill 4 prevent the concentration of bodies 7 in one place and ensure that bodies 7 contact with the grids over the entire surface of the vibrating screen. 2 Il.

Description

/

(L

8I g

T T 9 5

/ cl

about

YU

about to

OE

1

the grid 3 by means of insulators 8 and a grid 4 located under it from separate sections 9. Vertical guides 5 are installed between the grid 3 and the grid 4 to form separate chambers 6 for accommodating the beater bodies 7 of resilient electrically conductive material. Within each chamber 6, the individual portions of the grid 4 are located at an angle to the grid 3. The size of the chopping bodies 7 is less than the distance between the grid 3 and the upper edge of the grid 4 on each section 9. The base 1 performs reciprocating movements in the plane of the grid 3. Partitioned the dispersed material is fed to the grid 3. The chops of the body 7 under the action of vibration make elastic movements within the limits of sections 9, the deformation. The invention relates to the technique of separation and classification of granular substances, namely, screening devices for separating dispersed materials capable of forming explosive mixtures pylevoz- stuffy, and can be used in the chemical, pharmaceutical and other industries.

The purpose of the invention is to increase the efficiency of fractional separation of electrifying dispersed materials and reduce the explosion and fire hazard of the separation process.

FIG. 1 shows a sieve, a general view; in fig. 2 - additional sector sieve.

The sieve has a grounded frame 1 connected to a vibro-drive 2 reciprocating motion, on which the grid (sieve) 3 is fixed and a grid or sieve 4 located below it, between which vertical guides 5 are installed with the formation of separate chambers 6, inside which bodies are placed 7, for example balls, of elastic material, for example rubber. The grid 3 is fixed on the frame 1 by means of insulators 8. The grid 4 is made of separate sections (sectors) 9 located within each chamber 6 at an angle to the grid 3. The chops of the body 7 are made of electrically conductive material, for example, of electrically conductive rubber. The size of the chop bodies 7 is less than the distance between the grid 3 and the upper edge of the grid 4 in each area (sector) 9.

Vibrating sieve works as follows.

When the vibrodrive 2 is turned on, the reciprocating movement of the bed 1 is set in motion, vibrating in the plane of the sieve 3. The dispersed material to be fractionated is grid 3 and grid 4. The charge is removed from grid 3 by using chopping bodies 7 of electrically conductive material. The bodies 7 transfer charge from grid 3 to

lattice 4. The amount of charge transferred is insufficient to initiate an explosion of a dusty air mixture of particles of dispersed material. Due to the fact that the size of the bodies 7 is less than the distance between the grid 3 and the upper edge of the grid 4, direct contact of the grid 3 with the grid 4 through the bodies 7 does not occur, which ensures the absence of powerful spark discharges. The guides 5 on the grill 4 prevent the concentration of bodies 7 in one place and ensure the contact of bodies 7 with grids over the entire surface of the vibrating sieve. 2 Il.

separation, served on a sieve 3, placed on isolators 8. Rubber balls 7

5, under the action of vibrational vibrations, they begin to make elastic movements that freely bounce and deform the upper 3 and lower 4 sieves within sector 9. Guides 5 on the lower sector sieve 4 prevent the rubber balls from concentrating in one place and ensure the balls come in contact with the sieves over the entire surface devices. The local deformations of the upper and sector sieves caused by the free elastic displacements of the balls contribute to an increase in the productivity of the device.

In the process of fractional separation of dielectric dispersed materials due to the triboelectrification on the powder, a significant electrical discharge is formed.

In the case of using a grounded screen, electrostatic spark discharges arise from dust clouds formed in the volume of the device and from individual particles of the dispersed material. As a result of these bits, initiation is possible.

5 explosions and claps, as well as sintering and agglomeration of particles on a sieve at discharges of lesser intensity or absence of explosive concentration of dust in the air. The sintering of the particles causes a decrease in the separation efficiency and rapid wear of the screens.

0 When installing sieve 3 on insulators, due to the absence of charge inflow from the ground and the appearance on the sieve 3 of electrostatic charge, of the same name as the charge particle of the dispersed material, the conditions for the formation of electrostatic charges from the material on the sieve 3 are mostly are. However, it becomes necessary to remove the charge from the sieve 3, which is achieved by using balls of electrically conductive elastomeric material. Due to the fact that the size of the balls is less than the distance between the grid 3 and the upper edge of the grid 4, direct contact of the sieve 3 with the sector sieve 4 does not occur through the electrically conducting balls, which ensures the absence of powerful spark discharges. However, when an electrically conductive ball comes in contact with a charged sieve, some of the electrostatic charge determined by the electrical capacity of the ball flows to it, and then when the ball falls and is connected to a grounded sector sieve 4, this charge flows to the ground loop. Thus, a discrete transfer from the insulated sieve 3 to the ground loop occurs.

The magnitude of the unit portable charge depends on the speed of the ball, its contact time with the electrified sieve 3, its size and electrical resistivity. These parameters are chosen on the basis of well-known principles in such a way that the charge carried by one ball in one transfer event does not exceed the value at which the initiation of the explosion of a dust-air mixture and the sintering of particles of the dispersed material is possible.

Testing a device for the frictional separation of dispersed materials with grounded sieve 3 and with insulated, using balls with a diameter of 30 mm

rubber with a specific volume electrical resistivity of 105 ohm-m showed that, all other conditions being equal, when sifting powdered sulfur, the separation efficiency increased from 82% to 95%, and the energy of electrostatic discharges, estimated by the charge flowing in the sieve grounding circuit 3, decreased from 9.7 mJ to 0.01 mJ, which provides almost complete intrinsic safety of the process.

0

Claims (1)

Invention Formula Vibrating sieve, including a grounded frame, connected to the vibration drive, on which the grid is fixed and the grid located below it, between which vertical guides are installed with the formation of separate chambers for accommodating chopping bodies of elastic material, in order to increase the efficiency fractional separation of electrifying dispersed materials and reducing the explosion and fire hazard of the separation process, the mesh is fixed on the frame by means of insulators, the grid 5 is made of separate sections located within each chamber at an angle to the grid, the chops of the body are made of electrically conductive material, and their size is smaller than the distance between the grid and the upper edge of the grid on each section.