RU2818413C1 - Centrifugal counterflow mill - Google Patents

Abstract

FIELD: devices for grinding various materials.

SUBSTANCE: invention relates to devices for grinding various materials and can be used in production of construction materials. Centrifugal counterflow mill comprises two housings 1 interconnected by tangential channel 2, the side walls of which converge in the plane of symmetry of the centrifugal mill at angle of 120…150°. In each housing 1 there is rotor 3 made with possibility of rotation in the direction of the corresponding outlet hole of the channel. In tangential channel 2 there is discharge branch pipe 4 equidistant from rotors 3 rotation axis. Loading branch pipes 5 in each housing 1 for supply of ground material are located on an arc of a circle equal to 50…280°, counting from straight line passing through centres of rotation of rotors 3, and radius equal to 1/4…3/4 of radius of rotor 3 with centre on vertical axis of the latter. At the lower end of each loading branch pipe 5 there is inclined cut 6 at angle of 45° on the side opposite to rotation of corresponding rotor 3. Each rotor 3 consists of horizontal disk 7, on which there are rectilinear accelerating blades 8, which have cutout 9 corresponding to the profile of loading branch pipe 5 with provision of a process gap. Rectangular ledges 10 with width D_max are rigidly attached to the upper surface of each horizontal disc 7, each of which adjoins with a side edge with height of (0.05...0.1)D_max to the working surface of rectilinear accelerating blade 8 in the direction of its rotation, where D_max is the maximum particle size of the initial material. On the periphery of each of horizontal disks 7 along the perimeter vertical collar 11 is rigidly fixed, and also through square holes 12 are made with side equal to (0.05...0.1)D_max, each of which adjoins vertical collar 11 and rectangular ledge 10. To lower surface of horizontal disks 7 under each square hole 12 to its edges 13 is rigidly attached, for example by welding, box-type dust collector 14 with vertical walls with height of 0.1D_max in planes of edges of through square hole 12 and external cut 15 with profile of horizontal disc 7.

EFFECT: increasing the efficiency of the grinding process and productivity of the finished product.

1 cl, 5 dwg

Description

The invention relates to devices for grinding various materials and can be used in the production of building materials, as well as in other industries.

A centrifugal mill is known (Semikopenko I.A., Voronov V.P., Gorban T.L., Lunev A.S. Determination of the power spent on grinding material particles in a centrifugal counterflow mill taking into account the influence of counter flows // Vestnik BSTU im. V.G. Shukhov, No. 3, 2016, pp. 84-86), containing a housing with a loading pipe on its cover and a discharge pipe, as well as a rotor with accelerating blades installed in it.

The design of a centrifugal impact mill is also known (USSR Copyright Certificate for invention No. 671839, В02С13/14, publ. 07/05/1979, Bulletin No. 25), containing a stepped housing, each subsequent stage in which, counting as the material moves, is made of a larger diameter , a stepped rotor with blowers located horizontally in the housing, loading and unloading pipes.

The technical problem of the known designs is the low efficiency of the grinding process and the low grinding fineness.

The closest technical solution to the proposed one, adopted as a prototype, is a centrifugal mill (RF Patent for invention No. 2567522, B 02 C 13/26, publ. 11/10/2015, Bulletin No. 31), containing two housings located in the same plane and connected to each other by a tangential channel common to both housings, in each housing there is a rotor configured to rotate in the direction of the corresponding outlet opening of the channel, on which accelerating blades are fixed, in the tangential channel there is a discharge pipe equidistant from the axes of rotation of the rotors, loading pipes in each housing for supplying crushed material are located on a circular arc equal to 50...280°, counting from a straight line passing through the centers of rotation of the rotors and with a radius equal to 1/4...3/4 of the radius of the rotor with a center on the vertical axis of the latter, at the lower end of each loading the nozzle has an inclined cut at an angle of 45° on the side opposite to the rotation of the corresponding rotor, each accelerating blade has a cutout corresponding to the profile of the loading nozzle providing a technological gap, the side walls of the tangential channel converge in the plane of symmetry of the mill, the angle between the converging walls is 120-150° .

The following set of prototype features coincides with the essential features of the claimed invention: two housings connected to each other by a tangential channel; in each housing there is a rotor configured to rotate in the direction of the corresponding outlet opening of the channel, on which the accelerating blades are fixed; in the tangential channel there is a discharge pipe, equidistant from the axes of rotation of the rotors; the loading pipes in each housing for supplying the crushed material are located on a circular arc equal to 50...280°, counting from a straight line passing through the centers of rotation of the rotors and with a radius equal to 1/4...3/4 of the radius of the rotor with the center on the vertical axis of the latter; at the lower end of each loading pipe there is an inclined cut at an angle of 45° on the side opposite to the rotation of the corresponding rotor; each accelerating blade has a cutout corresponding to the profile of the loading pipe, ensuring a technological gap; the side walls of the tangential channel converge in the plane of symmetry of the mill; the angle between the converging walls is 120-150°.

Despite the fact that in the prototype the relative speed of movement of the crushed material is more than 300 m/s, the grinding efficiency of the material is low. This is due to the collision of large and small particles in counter flows of material,coming off the rotors. At the same time, particles of the finished product in the general flow reduce the efficiency of destruction of large particles. The lack of preliminary separation of particles by size before they are fed to the accelerating blades reduces the efficiency of grinding.

The invention is aimed at increasing the efficiency of the grinding process and the productivity of the finished product.

This is achieved by the fact that the centrifugal counterflow mill contains two housings connected to each other by a tangential channel, the side walls of which converge in the plane of symmetry of the mill at an angle of 120-150 ⁰ . Each housing has a rotor configured to rotate in the direction of the corresponding outlet opening of the channel. The tangential channel has a discharge pipe equidistant from the axes of rotation of the rotors. The loading pipes in each housing for supplying the crushed material are located on a circular arc equal to 50 - 280°, counting from a straight line passing through the centers of rotation of the rotors and with a radius equal to 1/4 - 3/4 of the radius of the rotor with the center on the vertical axis of the latter. At the lower end of each loading pipe there is an inclined cut at an angle of 45° on the side opposite to the rotation of the corresponding rotor. Each rotor consists of a horizontal disk on which rectilinear accelerating blades are fixed, which have a cutout corresponding to the profile of the loading pipe, ensuring a technological gap. According to the proposed solution, rectangular ledges of width D _max are rigidly attached to the upper surface of each horizontal disk, each of which is adjacent with a side edge of height (0.05...0.1) D _max to the working surface of a rectilinear accelerating blade in the direction of its rotation, where D _max - maximum particle size of the starting material. At the periphery of each of the horizontal disks, a vertical bead is rigidly fixed along the perimeter, and through square holes are made with a side equal to (0.05...0.1)D _max , each of which is adjacent to the vertical bead and a rectangular ledge. A box-shaped dust collector with vertical walls 0.1D _max high in the planes of the edges of the through square hole and an external cut with the profile of a horizontal disk is rigidly attached to the lower surface of the horizontal disks under each square hole and to its edges.

The essence of the invention is illustrated by the drawing, where in FIG. 1 shows section A-A in Fig. 2 (section of a centrifugal counterflow mill); fig. 2 - section B-B in Fig. 1 (straight-line accelerating blades); fig. 3 - section B-B in figure 1 (rectangular ledges and box-shaped dust collector); fig. 4 - section Г-Г in Fig. 1 (loading pipe and vertical collar); fig. 5 - section D-D in Fig. 3 (square hole and vertical collar).

The centrifugal counterflow mill contains two housings 1, connected to each other by a tangential channel 2, the side walls of which converge in the plane of symmetry of the centrifugal mill at an angle of 120-150°. Each housing 1 has a rotor 3, configured to rotate in the direction of the discharge pipe 4, located in the tangential channel 2 and equidistant from the axis of rotation of the rotors 3. The loading pipes 5 for supplying the crushed material in each housing 1 are located on a circular arc equal to 50... 280°, counting from a straight line passing through the centers of rotation of the rotors 3 and with a radius equal to 1/4...3/4 of the radius of the rotor 3 with its center on the vertical axis of the latter. At the lower end of each loading pipe 5 there is an inclined cut 6 at an angle of 45° on the side opposite to the rotation of the corresponding rotor 3. Each rotor consists of a horizontal disk 7, on which rectilinear accelerating blades 8 are rigidly fixed, for example by welding, which have a cutout 9, corresponding to the profile of the loading pipe 5, ensuring a technological gap. Rectangular ledges 10 of width D _max are rigidly attached to the upper surface of each horizontal disk 7, for example by welding, each of which is adjacent with a side edge of height (0.05...0.1) D _max to the working surface of the rectilinear accelerating blade 8 in the direction of it rotation, where D _max is the maximum particle size of the starting material. On the periphery of each of the horizontal disks 7 along the perimeter, a vertical collar 11 is rigidly fixed, for example by welding. On the periphery of the horizontal disks 7 there are through square holes 12 with sides equal to (0.05...0.1)D _max , each of which adjacent to the vertical collar 11 and the rectangular ledge 10. To the lower surface of the horizontal disks 7 under each square hole 12, to its edges 13, a box-shaped dust collector 14 with vertical walls 0.1D _max in height in the planes of the edges of the through square hole 12 and external cut 15 with the profile of a horizontal disk 7.

A centrifugal counterflow mill works as follows.

The crushed material, for example limestone, is fed through the loading pipe 5 to the horizontal disk 7 of each rotor 3. Due to the fact that the loading pipes 5 of each housing 1 are offset relative to the axes of rotation of the rotors 3, polydisperse particles of the crushed material in each period of time fall only on one of the rectangular ledges 10 adjacent to the accelerating blades 8.

Large particles overcome the vertical walls of the rectangular steps 10 and, due to the Coriolis force, are pressed against the working surface of the rectilinear accelerating blades 8.

The arrangement of the loading pipes 5 in plan and the length of the accelerating blades 8 of the horizontal disks 7 ensure the counter-movement of the flows of large particles of the crushed material and their frontal collision in the tangential channel 2.

The speed of large particles directed towards each other from the housings 1 into the tangential channel 2 exceeds the speed of destruction of the material particle, as a result of which they are effectively crushed. Particles of crushed material from tangential channel 2 are directed to the discharge pipe 4. Particles of the finished product, moving along the vertical wall of the rectangular ledge 10 in the direction of the vertical collar 11, fall into the through square hole 12 and, through box-shaped dust collectors 14, are directed into the tangential channel 2 under the horizontal disk 7 and then into the discharge pipe 4. As a result of the application of the proposed mill design, preliminary separation of large and small particles is ensured before they are fed to the accelerating blades 8, as well as selective self-grinding of particles in counter frontal flows, depending on their size in the tangential channel 2. The height of the rectangular ledges 10 makes it possible to separate particles of the finished product from the main flow, directed for grinding into the tangential channel 2. The presence of a vertical collar 11 allows particles of the finished product to be directed into a through square hole 12 and then into a box-shaped dust collector 14. An inclined cut 6 at the lower end of each loading pipe 5 prevents jamming of material particles between the loading pipe 5 and the horizontal disk 7. To ensure the operation of a centrifugal counterflow mill accelerating blades 8 have a cutout 9 corresponding to the profile of the loading pipe 5, ensuring a technological gap.

All of the above will improve the efficiency of the grinding process and increase the productivity of the finished product due to preliminary removal of small particles before they are fed to the accelerating blades and selective impact on the crushed material.

Claims (1)

Centrifugal counterflow mill containing two housings connected to each other by a tangential channel, the side walls of which converge in the plane of symmetry of the mill at an angle of 120-150°, each housing has a rotor configured to rotate in the direction of the corresponding outlet opening of the channel, the tangential channel has a discharge a pipe equidistant from the axes of rotation of the rotors; the loading pipes in each housing for supplying the crushed material are located on a circular arc equal to 50-280°, counting from the straight line passing through the centers of rotation of the rotors, and with a radius equal to 1/4 - 3/4 of the radius rotor centered on the vertical axis of the latter, at the lower end of each loading nozzle there is an inclined cut at an angle of 45° on the side opposite to the rotation of the corresponding rotor, each rotor consists of a horizontal disk on which straight accelerating blades are fixed, which have a cutout corresponding to the profile of the loading nozzle providing a technological gap, characterized in that rectangular ledges of width D _max are rigidly attached to the upper surface of each horizontal disk, each of which is adjacent with a side edge of height (0.05...0.1) D _max to the working surface of the rectilinear accelerating blade in the direction of its rotation, where D _max is the maximum particle size of the source material, on the periphery of each of the horizontal disks a vertical collar is rigidly fixed around the perimeter, and through square holes are made with a side equal to (0.05...0.1) D _max , each of which is adjacent to a vertical collar and a rectangular ledge, to the lower surface of the horizontal disks under each square hole, a box-shaped dust collector with vertical walls 0.1D _max high in the planes of the edges of the through square hole and an external cut with the profile of the horizontal disk is rigidly attached to its edges.