SU1299620A1 - Centrifugal multiple-stage mill - Google Patents

Abstract

The invention relates to centrifugal multistage mills and provides for the classification of the material according to grinding steps into three fractions under any operating conditions and allows -25 15 28 10 (L nat, f

Description

It is necessary to reduce the specific energy consumption for grinding, to reduce the amount of wear on the working parts per unit of the product obtained, to obtain a metallomagnetic fraction suitable for reuse, to obtain slag fertilizers of a given granulometric composition. The mill consists of three similar grinding stages, increasing in the direction of discharge. Each grinding stage includes, respectively, an accelerating disk 4, 5, 6, a conical breakaway deck 7, 8, 9 magnetic-one-sided linear inductor 10, 11, 12, sifting down a cone1

The invention relates to devices for the fine grinding of materials, in particular, multistage centrifugal mills, and can be used, for example, for grinding dump steelmaking slags and grains for feed containing their impurities from metallomagnetic fractions, and also for separating metallomagnetic impurities from chemical technologies and technologies for obtaining non-magnetic components of powder metallurgy.

The purpose of the invention is to increase the homogeneity, granulometric composition of the milled product of a given size, without admixture of the metallomagnetic fraction, reducing the energy intensity of the grinding process, increasing the service life of the working bodies.

FIG. 1 shows a centrifugal multistage mill, a longitudinal section; in fig. 2 — node I in FIG. 1 (the form of implementation of the pitched board); in fig. 3 - loading window of the first grinding stage, top view; in fig. 4 - section aa in fig 1; Fig. 5 is a diagram of an inductor with excitation windings; in fig. 6 is a diagram of the release of a magnetic particle.

The centrifugal multistage mill consists of three grinding stages of similar structural design. The nodes and parts that form the grinding stages, on a different sieve 13, 14, 15. The accelerating disks 4, 5, 6, inductors 10, 11, 12 receiving funnels 17, 18, mounted on the vertical shaft 3, make up the rotor of the mill 1) 1. The mill has pitched boards 27.28, made in the form of a conical surface of scaly sieve. A magnetic one-sided linear inductor 10, 11, 12 consists of a magnetic core, made on the outer surface in the form of a cone with grooves for windings connected to the mains phases, and ensures the separation of the metallomagnetic fraction from the mass of material. 3 hp f-ly, 6 ill.

five

The measures are increased in the direction from the hopper I to the discharge openings and are installed in series in the housing 2. The mill has one common vertical shaft 3.

Each grinding stage consists, respectively, of an accelerating disk 4, 5 and 6, a conical fender deck 7, 8 and 9, a magnetic one-sided linear inductor 10, 11 and 12, a screening cone sieve 13, 14 and 15. Accelerating disks 4, 5 and 6 the grinding steps are made by analogy of the impellers of centrifugal fans, with the only difference that their blades are straight and are shifted relative to the radius back to the direction of movement. The acceleration disk 4 of the first grinding stage is fixed on the vertical 3 using a clamp 16. The accelerating disks 5 and 6 second the third grinding stages are secured by similar clips 16 on the receiving funnels 17 and 18, which are attached to the common vertical shaft 3 with the help of crosses 19. On the outer surface of the receiving funnels 17 and 8, inductors 11 and 12 are also strengthened second and third grinding stages. The inductor 10 of the first stage is grinding-: neither finish: en by the clamp 22. The large base inductors 10, 11 and 12

5 grinding steps attached to

0

0

the lower bases of m acceleration x disks 4, 5 and 6.

Accelerating disks 4, 5 and 6, inductors 0, 11 and 12, receiving funnels

The removal of the metallomagnetic fraction from the mass at each stage of 17 and 18, mounted on the vertical-5 grinding, is carried out as follows.

The main shaft 3 of the mill is the rotor of the mill, which is its main assembly. Vertical shaft 3 mills mounted in bearings 23 and I 24, which are mounted on the upper

25 and the bottom 26 of the support plates mounted coaxially relative to the vertical shaft 3 on the housing 2.

Dp of effective removal of the first and second stages of grinding of non-magnetic particles of the product of grinding of given sizes sifted through conical sieves 15 and 14 in the mill have pitched boards 27 and 28, which are made in the form of a conical surface of flake sieve and are installed with a large base to the discharge ring opening 29. to the foundation with the help of four supporting paws 30 and racks 31. The ground material is directed onto the first acceleration disk 4 from the loading hopper 1 with the help of a funnel 32 through loading e window 33 of the upper base plate 25.

The magnetically unilateral linear inductor 10, II and 12 of each grinding stage (for all stages the inducers are similar in structure) consists of a magnetic circuit 34 and three circular windings 35. The magnetic circuit 34 of the inductor 10, 11 and 12 is made of electrical steel. The implementation of the magnetic conductor 34 of electrical steel due to the need to reduce losses to hysteresis and eddy currents, which heat it in the process. On the outer surface of the magnetic circuit 34 is made in the form of a cone with grooves 36. for the windings 35, which are connected to the phases of the network A, B, C. The fastening of the windings 35 in the grooves 36 is possible using epoxy resins. Other mechanical fastening methods are possible.

Since the windings 35 create a traveling magnetic field only along one surface of the magnetic circuit 34, the magnetic inductor thus constructed is magnetic one-sided. When this magnetic field runs along the conical surface of the magnetic circuit 34 from phase A to

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in a way.

On the surface of the cone sieve 13, 14, and 15 of each step, the metal-magnetic part 37 moves, freeing itself from slag during the destruction process. The magnetic field of the inductor 10, 11 and 12 running from phases A and B and C, having a linear speed V field, crosses the particle 5 37 having speed Vj (m / s). The magnitude of the induced EMF in particle 37 is directly proportional to the relative velocity of the particle’s intersecting magnetic field (VOT V "„ -). Under the action of a running floor in a particle 3, an emf is induced, but particle 37 is a closed conductor, and in a closed conductor under the action of an emf induced by a running field, a current (multi-phase) flows along the lines of least resistance. The interaction of the induced current in the particle 37 with the traveling magnetic field of the inductor creates a force that pushes (t is not) the particle 37 from the mass of the product (lifts it from the sieve surface to the surface of the inductor). The magnitude of the force according to Ampere's stake is determined by the formula

F g in. I,

where F is the force with which the particle is removed, rises from the moving mass;

I - induced by a running field then particles;

E is the largest size (length) of a particle;

B - magnetic induction of a running floor, the value of which depends

thirty

35

40

45

50

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strainer voltage applied to the windings.

The force F acting on the particle may be such that the particle will not only be extracted from the total mass, but also stick to the surface of the inductor. By sticking to the surface, the particle does not remain in place, it runs, glides along the surface in the direction of the magnetic field. Its speed is determined by the mass, resistance force from the friction of the movement, due to the force of attraction (pressure) of the particle to the weight of the inductor.

B and then to phase C, then again in the same sequence.

Extraction of the metallomagnetic fraction from the mass at each grinding stage is carried out as follows.

0

in a way.

Along the surface of the cone sieve 13, 14, and 15 of each grinding stage, a metal-magnetic particle 37 moves, freeing itself from slag during the destruction process. The magnetic field of the inductor 10, 11 and 12 running from phase A and B and C, having a linear velocity V field, crosses the particle 5 37 having a velocity Vj (m / s). The magnitude of the induced emf in particle 37 is directly proportional to the relative velocity of the particle crossing the magnetic field (VOT V „„ -). Under the action of a running floor, EMF is induced in particle 37, but particle 37 is a closed conductor, and in a closed conductor under the action of an emf induced by a running field, a current (multi-phase) flows along the lines of least resistance. The interaction of the inductor induced in the particle 37 with the traveling magnetic field of the inductor creates a force that pushes (t is not) the particle 37 out of the mass of the product (lifts it from the sieve surface to the surface of the inductor). The magnitude of the force according to Ampere's law is determined by the formula

F g in. I,

where F is the force with which the particle is removed, rises from the moving mass;

I is the particle current induced by the running field;

E is the largest size (length) of a particle;

B - magnetic induction of a running field, the value of which depends

five

0

strainer voltage applied to the windings.

The force F acting on the particle may be such that the particle will not only be extracted from the total mass, but also stick to the surface of the inductor. By sticking to the surface, the particle does not remain in place, it runs, glides along the surface in the direction of the magnetic field. Its speed is determined by the mass, resistance force from the friction of the movement, due to the force of gravity of the particle to the weight of the inductor.

Changing the magnitude of the magnetic induction by changing the magnitude of the applied voltage, you can choose its rational value, at which there will be a complete extraction of metallomagnetic particles from the total mass of grinding methods and no wear of the working surface of the inductors due to friction about them. Extraction of magnetic particles from the mass by grinding steps does not occur only if there is no voltage on the windings of the inductors. In this case, the crusher works and classifies the pool only with the help of screening screens according to the size of grains (particles).

To improve the process of extracting the metallomagnetic fraction, the angle of inclination of the working surface of the inductor should correspond to the angle of inclination of the screening sieve. The working gap between the sieve and the surface of the inductor is determined by the amount of the metal-magnetic fraction in the product to be ground, the productivity of the grinding stage.

The successive arrangement of the phases of the winding along the length forming the cone of the inductor eliminates the influence of the rotation frequency on the process of extracting the metlomagnetic particles from the comminuted mass,

Complete extraction of the metallomagnetic fraction from the comminuted raw material, as well as obtaining the product of grinding the equalized particle size distribution of a given size is possible with the sequential installation of several grinding stages, ensuring consistently increasing working speeds from the first to the last, symmetrically located along the same vertical axis, which should be at least three, the need for setting up several successive stages is determined ambiguously Tew f the properties physico-mechanical comminuted materials (slag)

Different conditions of the destruction process. The magnitude of the rate at which degradation occurs varies for different materials within different limits, the boundary values of which in the shredder determine the effectiveness of the destruction process.

The increase in the working rates of destruction from the first to the subsequent grinding steps and the increasing total surface area of the grinding particles to be separated by metal-magnetic impurities, necessitates an increase in the working sizes of the inductors.

Centrifugal. Mill available mill works as follows.

The material to be crushed through the funnel 32 through the loading windows 33 of the upper support plate 25 enters the first acceleration disk 4. The passage through the working channels of the accelerating disk 4, the material (spack) is crushed. The material is crushed inside the working channels and when it strikes the baffle deck 7, the air flow through the working channels of the accelerating disk 4 contributes to the movement of the material,

The mass of the product crushed in the working channels of the accelerating disk 4 and the fender deck 7 of the first grinding stage enters the conical screening screen 15, where it is divided into three fractions. The metallomagnetic particles released from the slag during the destruction process, with the aid of a magnetic field running along the generatrix of the surface of the magnetic one-sided linear inductor 10, are extracted from the total mass, acquire a speed close to the velocity of the field, and are sent to the receiving funnel 17. Particles in the zone the entrance mouth of the funnel 17, when changing the direction of the magnetic flux, retains its direction of movement due to the force determined by the mass and the acquired velocity (acceleration). In the mill operation, the angular velocity between the inductor 10 and the receiving funnel 17 is zero (the rotation frequency is the same), and the particles extracted from the medium (mass) do not experience the effect of centrifugal forces. The distinctive features of the mill operation allow the metal-magnetized particles their magnetic field of velocity, force of gravity and air flow is output through the receiving hopper 17 into the finished product.

The nonmagnetic fraction, remaining with the cone sieve 15 of the first grinding stage, is classified during its movement along it.

mechanically. Particles of a given size, sifted through a cone sieve 15, are derived from the total remaining mass. The mass of particles not screened through the conical sieve 15 constitutes the initial fraction of material that enters the acceleration disk 5 of the second stage. The performance of the accelerating disk 5 of the second grinding stage is lower than the productivity of the first by the total value of the mass of particles selected in the classification process. With an increase in the working speed of destruction in the accelerating disk 5 of the second grinding stage, its productivity is reduced by the value of the mass of separated particles due to a decrease in the height of the working blades.

The classification of particles entering after destruction in the second stage on the screening cone sieve 14 of the second stage is carried out in a similar way.

The receiving funnel 18 of the second grinding stage is selected according to the arrangement of the funnel 17, but its dimensions along the diameter of the cone and the cylindrical particle are increased. Increasing the size of the receiving funnel 18 is necessary because of the increasing volume of the metal-magnetic fraction separated in the second and previous grinding stages.

The non-magnetic fraction of a given size selected during the mechanical sieving process enters the scaly conical surface of the ramp boards 27 and 28 and is transported under overpressure by a layer of air flow created by the acceleration disks 5 and 6 of the second and third grinding steps. Stack from the surface of the pitched planks 27 and 28, particle. through annular holes .29 are removed from the mill.

Reduced overpressure c. The working volume of the second and third grinding stages due to the exhaust of air through the scaly surfaces of the ramp boards 27 and 28 reduces the speed of the material moving through the screening sieves 13, 14 and 15, increases the coefficient of mechanical and magnetic separation of particles, reduces energy costs for air ventilation .

996208

Pass the last stage of grinding, whose productivity is less than the previous one, and is classified by analogy of the first two,

5 The material is displayed in aggregate.

from the mill in three separate fractions: output A is a metal-magnetic fraction, output B is an undersized fraction, output C is a fraction of a given

 About the particle size distribution.

Classification of the material by stages into three fractions under any operating conditions of the mill allows reducing the specific energy consumption for grinding, reducing the amount of wear on the working parts per unit of the product, obtaining a metal-magnetic fraction suitable for reuse in steelmaking, Slag fertilizers of a given granulometric composition, which, when introduced into the soil, increase the yield of agricultural crops.

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Claims (4)

Invention Formula I. Centrifugal multistage mill for grinding dumps 30 steelmaking slags containing a receiving-distributing chamber with loading and unloading openings in which a stepped rotor is mounted in the form of 35 vertical shaft acceleration disks with paddles whose diameters increase if- chipper deck opposed to booster disks, conical sieves and conical 40 pitched boards, characterized in that, in order to increase the uniformity of the grain-size composition of the grinding product of a given size, without admixture of the metal-magnetic fraction, reduce the energy intensity of the grinding process, increase the service life of the working bodies, the mill is equipped with a receiving funnel installed at each stage of the rotor and 50 magnetically uniform linear inductor, made in the form of a symmetric truncated cone, fixed with a smaller base on the vertical shaft, and a large, base, 55 acceleration disk and having horizontal grooves on the outer surface for mounting three-phase windings. 2, the mill according to claim 1, characterized in that the outer diameters of the inductors and receiving hoppers are made increasing in the direction towards the discharge openings. 3 Mill in PP, 1 and 2, characterized in that the height the blades of the acceleration discs decrease in the direction of the discharge openings. 4. Mill on PP. 1 - 3, characterized in that the working surface of the pitched boards is made in the form of a sieve with scales. Air J3 gOae. 3 X 29 (network times Ш5 Гч. FIG. five ,five. //./2 %  I 37 FIG. 6