SU1005895A1 - Centrifugal multistep mill - Google Patents

Abstract

A CENTRIFUGAL MULTIPLE MILL, containing a stepped body, a disk stepped rotor, each step of which, counting along the material's motion, is made of a larger diameter, each of the rotor discs have eee% ai "H" e working Xch blades, one part of each of which is made is linear and directed radially to the rotor, and fixed end plates are installed on the end upper surface of each stage of the body, the lower part of the body steps being made in the form of a truncated cone passing into the cylinder, Loading and unloading nozzles, characterized in that, in order to increase the efficiency of grinding and material separation, the last step of the mill is equipped with a lid with central and circumferential apertures, the slats rotated with P0D 10-45 ° between the last 1% ; to; the tangential circumference of their installation, the second part of the blades is made straight and inclined to its radial part at an angle of PO-120 °, and the fender plates with respect to the rotor have a concave shape.

Description

The invention relates to devices for selective grinding of fragile materials. Simultaneous separation of grinding products into fractions and can be used in the chemical, construction, food and other industries.

A known centrifugal multistage mill comprising a stepped housing, a disk rotor, each step of which, counting along the material’s movement, is made of a larger diameter, has working blades on each disk, with the lower part of the steps of the housing made in the form of a truncated cone that passes into the cylinder, the loading and discharge pipe 1.

Closest to the invention is a centrifugal multistage mill containing a stepped body, a disk stepped rotor, each step of which, counting along the material's movement, is made of a larger diameter, and on each rotor disk there are composite working vanes, one part of each of which is made straight and directed radially to the rotor, and fixed end plates are installed on the end upper surface of each stage of the hull, with the lower part of the steps of the hull being truncated Nogo-conical transition present in the cylinder, the loading and unloading tubes 2.

The disadvantage of the mills is the low grinding efficiency, the impossibility of dividing the ground material into fractions. In addition, with the destruction of many abrasive materials, for example, cakes - products of synthetic diamond synthesis, electrocorundum, rapid wear of the fender plates and the impossibility of separating diamonds from the ground mixture is observed.

The purpose of the invention is to increase the efficiency of grinding and material separation.

This goal is achieved by the fact that in a centrifugal multistage mill containing a stepped body, a disk stepped rotor, each step of which, counting along the material movement, is made of a larger diameter, and on each rotor disk there are composite working vanes, one part of each of which is made linear and directed radially to the rotor, and fixed end plates are installed on the end upper surface of each stage of the hull, with the lower part of the steps of the hull being truncated a conical transition present in the cylinder, the loading and unloading pipes, the latter stage mill has a lid with a central and a peripheral circumferentially spaced apertures between Rich

the latter were mounted strips rotated at an angle of 10-45 ° to the tangential circumference of their installation, the other part of the blades is made straight and inclined to its radial part at an angle PO-120 °, and the fender plates relative to the rotor have a concave shape.

FIG. 1 shows a centrifugal multistage mill, general view; in fig. 2 shows section A-A in FIG. one; in fig. 3 shows a section BB in FIG. one; in fig. 4 — node I in FIG. 2; in fig. 5 is a diagram illustrating the process of ejecting a particle and its impact on a baffle plate; in fig. 6 shows a mounting scheme for classifying blades.

The mill contains a stepped housing 1, in which a stepped rotor 3 is mounted on a vertical shaft 2. On the surface of each rotor there are accelerating vanes 4, having a complex shape — apr 0, the linear part 5 and bent 6 at an angle PO-120 ° to the linear part of the same shoulder blades. The blades in the center of each rotor with their bent part form a distribution zone 7 with slots 8. On the upper surface of each stage of the body there are fixed bumper plates 9, having the form of a cylindrical surface with a parallel forming of the rotor and concave in its direction. The lower part of each stage of the mill has the shape of a truncated cone with a transition to the cylindrical part 10, which is included in the distribution zone.

On the end cap 11 of the third stage there are peripheral holes 12, and on the end cap 13 of the mill there are peripheral holes 14 and an axial hole 15 for outputting the small stage and the mill circumferentially, in the space between the end caps of the third stage and the mill there are installed classifying strips 16 at an angle of 10 -45 ° to the tangent drawn to the circumference of the setting of these blades.

A conical hopper 17 is fixed to the end cover of the mill for collecting a large fraction with a central opening 18 for withdrawing this fraction.

In the upper part of the stepped housing of the Mill is located the boot pipe 19.

The mill works as follows.

The source material through loading nozzle 19 enters distribution zone 1. Under the action of centrifugal forces developed during rotation of the rotor, the material particles through the slots 8 of the distribution zone fall on the surface of the accelerating blade 4. Moving along the surface of the discharge blade 4, the particles of the material are accelerated and take off from the surface of the scapula. When flying, particles of destructible material fall to the surface

plate 9, having the form of a cylindrical surface, and destroyed. The crushed pieces of material, sliding along the surface of the conical part of the first stage of the body, fall into the distribution zone of the second stage. In the subsequent steps of the mill, the particles of the material move in a manner similar to the first step.

After the third stage, finely dispersed material in a gaseous medium through the peripheral holes 12 in the end cap 11 of the third stage enters the space between the end caps of the third step and the mill and the passage between the classifying slats 16 installed at an angle of 10 The -45 ° to the tangent drawn to the circumference of the setting of these blades is split. Under the action of centrifugal forces, particles of the coarse fraction are thrown to the inner surface of the classifying strips 16 and through the peripheral holes 14 of the end face of the mill are diverted into a conical hopper 17, from which they are removed through the central hole 18, the fine fraction in the form of a spiral dust-air flow moves to an axial hole 15 and out of the classification zone.

Installing baffle plates that have a concave shape allows for the destruction of hard abrasive materials such as specs and electrocorundum to prevent wear on the latter. Such a form of baffle plates retains on its surface some part of the material being crushed, which in turn acts as a protective sheath, protecting this surface from wear.

Studies of the influence of the shape of the accelerating blades on the kinematics of particle movement through the distribution zone showed that making their curved part straight and at an angle of 110-120 ° to the straight radial part of the accelerating blade creates conditions for the non-stop movement of material particles on such a surface and their speedy exit through holes of this zone. If the second part of the blades is curved around the circumference, then some part

the material under the action of centrifugal forces developed during the rotation of the rotor is pressed against their surface, rotates with them, stopping the movement of newly introduced particles.

By varying the installation angle of the grading bars within 10-45 ° to the tangent, carried out to the circumference of the installation of these blades, it is possible to change the boundary of the division of material into fractions. When the installation angle of the slats is less than 10 ° and more than 45 °, the separation conditions deteriorate. Thus, for example, at the installation angle of the strips of 5 °, no separation occurs at all, since the material that has entered through the peripheral openings of the end cap of the mill remains in the corresponding zone of the classification chamber, and rotates in this zone under the action of centrifugal forces. When the angle of installation of the slats is 50 °, all the material carried by the air flow exits through an axial hole installed on the end cover of the mill.

For a better separation of the material into fractions, an additional amount of abutment may be supplied to the classification zone.

As noted earlier, the nature of the movement of destructible material in the second and third steps of the mill is similar to that of the first, but the destruction occurs at a higher loading rate.

The constructive solution of a centrifugal multistage mill allows, at each stage, to expose particles only to a single load. In the proposed device, the unloading of the material, first of all, flows through the most weakened areas, i.e. where dissimilar materials form a conglomerate. The intensity of the impact is adjusted by varying the frequency of rotation of the shaft of the stepped rotor of the mill. The degree of separation of the material is controlled by the mounting angle of the grading bars.

Thus, the use of the invention improves the efficiency of grinding and material separation in a centrifugal multistage mill.

FIG. 2

15

eight

Fig.d

sixteen

Figm

FIG. five

FIG.

Claims (1)

A CENTRIFUGAL MULTI-STAGE MILL containing a stepped case, a disk stepped rotor, each step of which, counting in the direction of movement of the material, is made of a larger diameter, and on each rotor disk there are composite working blades, one part of each of which is made rectilinear and directed radially towards the rotor, and On the end upper surface of each stage of the casing, fixed baffle plates are installed, the lower part of the stages of the casing being made in the form of a truncated cone passing into the cylinder, loading -screw and discharge pipes, characterized in that, in order to increase the grinding efficiency and material separation, the last stage of mill provided with a lid with a central circumferentially disposed and peripheral openings being provided between strips mounted poslednimi-%, rotated at an angle of 10-45 ° _to; the tangent circumference of their installation, the second part of the blades being straight and inclined to its radial part at an angle of BUT — 120 °, and the baffle plates are concave in relation to the rotor.