SU1238813A1 - Centrifugal apparatus for fractionating loose materials - Google Patents

Description

The invention relates to the technology of the separation of ground materials by size and can be used in the mining, coal, chemical, pigment, electronic and other industries.

The aim of the invention is to increase the fractionation efficiency due to the formation of a cylindrical vortex separation zone as well as a higher fractionation capacity by the drum.

FIG. 1 shows the proposed apparatus, a longitudinal section; in fig. 2 shows section A-A in FIG. one .

The device consists of two rings 1, located pair-allelic one to the other and rigidly connected at the same distance from the axis of rotation of the shaft 2, the longitudinal strut II 3 (the 1SCH design is made in the form of a squirrel wheel), two suction nozzles A, fixed On 1 external side surfaces of rings coaxially and supported by support 1 rods 5 through bearings 6 on a shaft of fan blades 7 mutually installed on shaft 2, fan drive 8 and 8 and rotation drive pulley B. b. The shaft 2 is mounted in bearings 10 supported on the foundation of the apparatus. The rods 3 may be made of metals, alloys, plastics, and other materials, depending on the physicomechanical properties of the material to be separated. Their cross-sectional shape can be from flat to round.

Structural solutions in this apparatus allow to achieve high performance and separation efficiency due to a dramatic increase in the living cross section of the screening surface, destruction of fine particles by the impact of aggregates, merging under the action of different forces, forming a cylindrical vortex separation zone with a width from the outer surface of the drum to the suction nozzle.

When the squirrel wheel rotates around it, an integral turbulent flow is formed, formed by local clearly delineated eddies of ha of each rod, between which there is a directed mass exchange. It was established experimentally that the structure of local flows (vortices) and, therefore, the integral0

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 The foot is determined with the squirrel wheel's rotational speed, as well as the pitch of the rods, their cross-sectional size and shape.

The aerodynamic drag force acting on a particle for a turbulent mode is proportional to the square of the velocity and density of the medium. When the bulk material enters the separation zone, the aggregates of short particles, as well as small aggregates with relatively large ones, are destroyed. When acquiring kinetic energy, large particles overcome the aerodynamic resistance of the medium in the separation zone and fly directionally tangentially to the circumference described by the radius of the distance between the particle and the squirrel wheel stem from its axis. Particles are separated according to their generalized dynamic characteristic j, taking into account the density, the shape of the particles and their size. Small particles formed mainly as a result of the destruction of the aggregates cannot acquire enough energy to overcome the aerodynamic resistance of the separation zone, since a significant part of the impact energy is spent on the destruction of the aggregates themselves. Therefore, small particles are captured by a rotating turbulent flow, in the central part of which the pressure is somewhat reduced. This contributes to the removal of small particles from the separation zone to the center of the squirrel wheel. This effect is enhanced by the blades of exhaust fans installed in hollow cylinders of a diameter smaller than a squirrel wheel, which does not disrupt the directional mass transfer in the separation zone I, the direction of movement of small particles in FIG. 1 is shown by arrows. The fan blades are fanned out. , counter squirrel wheel, which allows them to achieve greater performance at a lower speed of rotation.

The device works as follows.

The source material is fed by a feeder to the squirrel wheel rods 3. When the latter rotates around the rod 3, turbulent flows are formed, zones of pressure and low pressure from the outer and inner sides of the wheel, respectively. The underpressure zone is reinforced by blades of 7 exhaust fans rotating counter-squirrel wheel. Small particles (less than the boundary diameter of separation) under the influence of dynamic resistance of the air are captured by turbulent flows and drawn into the squirrel wheel, where they are removed by the air flow generated by the blades 7 exhaust fans, (Fig. 1 the direction of movement of small particles shown by arrows). Large particles (more than the boundary diameter of separation) under the action of impact energy are rejected in the direction of rotation of the squirrel wheel to form a fan in which the particle size increases with increasing distance from the axis of rotation of the squirrel wheel. The latter are accumulated in size classes in rectangular receivers mounted at different distances from the axis of rotation of the squirrel wheel (not shown). The adjustment of the apparatus is carried out by changing the speeds of rotation of the squirrel wheel and blades of the exhaust fans, as well as by changing the pitch of the rods, their diameter and the material with which they are lined.

Example. Make an experimental sample of the centrifugal apparatus:

Diameter of squirrel wheel, mm230

The internal diameter of the suction nozzle, mm. 190 Width of squirrel wheel, mm220 Width of suction nozzle, mm70 Diameter of rods, mm 10 Pitch of rods, mm 30 Number of revolutions of squirrel wheel,; rpm 400-1200 The number of revolutions of the fan, rpm 1500-2500

Testing of the experimental apparatus is carried out on finely ground synthetic ruby and silicon used as fillers for CEA sealing compounds.

The revolutions of the squirrel wheels and fan blades vary between 600–1000 and 2000–2500 r / m, respectively. The ruby and silicon productivity is 0.15 and 0.1 t / h, respectively.

The granulometric composition of the materials and the results of the separation of one of the experiments are given in Table. I (ruby) and) 2 (silicon).

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Editor I. Nikolaichuk

Compiled by 0. Popov Tehred O. Gortvay

Order 3325/4 Circulation 565 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

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Proof-reader I. Erdeyi

Claims (3)

1. CENTRIFUGAL APPLIANCE FOR FRACTIONATION OF BULK MATERIALS, including a loading chute, a hollow separation drum installed through it with through holes on a cylindrical surface, a drum rotation drive in communication with the drum cavity, and an end suction pipe coaxial with it and a fan, a fan drive connected to this pipe , unloading receivers, characterized in that, in order to increase the efficiency of fractionation due to the formation of a vortex cylindrical separation zone by the drum, qi indricheskaya drum surface is made up of longitudinal rods, a suction pipe having a diameter smaller than the diameter of the drum, and being connected with its end, and the fan is installed coaxially to the suction pipe to the possibility of oppositely relative to the drum rotation. 2. The apparatus of claim. ^ Characterized in that the longitudinal rods have a circular cross section. 3. The apparatus by π. 1, with the fact that, in order to increase the productivity of fractionation, the drum is equipped with an additional suction pipe with a fan mounted on the opposite end of the drum coaxially with it. L 1238813 A1 ί