RU2555913C1 - Method of materials mixing and grinding - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: ground material (2) and grinding bodies (3) are loaded in the rotating work vessel (1). Layer of the ground material and grinding bodies is formed on the internal surface of the work vessel under action of the centrifugal forces. Layer of the ground material and grinding bodies is treated using the fixed or rotating blade (5). From the layer of the ground material and grinding bodies by at least one blade the grinding bodies are separated and directed to wall of the work vessel. The ground material passes through slots and/or holes in the blade.

EFFECT: invention increases capacity of the grinding and mixing, reduces treatment cycle and increases level of dispersion of the ground material.

2 cl, 3 dwg

Description

The present invention relates to methods of grinding and mixing using centrifugal methods and is intended for dry and wet grinding of lump, grain and powder materials, as well as for the preparation of mixtures used in various industries.

A known method of grinding (Sidenko PM. Grinding in the chemical industry. Ed. 2nd, revised. M .: "Chemistry", 1977 - S. 158), in which the crushed material and grinding media are fed into a rotating relatively horizontal axis cylindrical or in the form of a truncated cone, the working capacity, where they are pressed by the gravitational forces to the walls of the working capacity and due to friction forces arising between the inner surface of the working capacity and grinding bodies, as well as the crushed material, are moved to the upper part of the working capacity bones, where under the influence of gravitational forces break away from the inner surface of the working capacity and fall into its lower part.

The disadvantage of this method is that the level of impact grinding effect on the material depends on the mass and height of the grinding media, and the abrasive effect of grinding media occurs at relatively low stresses of normal and shear deformations. All this leads to a significant increase in grinding time (up to several tens of hours), and the grinding itself occurs at a relatively low level of dynamic loading.

Of the known methods the closest to the claimed one is a method for preparing a molding sand-clay mixtures (RF Patent №2238818 of 11.06.2003, IPC ⁶ V22S 5/04. BI №30 from 27.10.2004), in which the ingredients treatment is carried out in a rotating cylindrical bowl rotating rotor with a blade, while the bowl is rotated at a speed that creates a pressure in the crushed material equal to 0.14-0.9 of the maximum compressive strength of the crushed material, and the blade relative to the bowl is rotated at a speed of 1.5 ... + 1.0 from the speed of rotation of the bowl.

A significant disadvantage of this method is that grinding and mixing is realized only due to the impact of particles of the crushed material on each other and in the process of collision with the surface of the working container, while the resulting level of shock and abrasion is insufficient for intensive grinding of durable materials. In addition, the speed of the particles of the ground mass is almost the same at the stages of free flight and collision with the surface of the working capacity, which significantly reduces the level of impact. The influence of these factors leads to a significant increase in grinding time and restrictions on the limiting values of fineness (dispersion) of the obtained crushed materials.

The technical result of the invention is to increase the productivity of the grinding and mixing process, reducing the duration of the processing cycle and increasing the level of dispersion (fineness of grinding) of the crushed material.

The technical result is achieved by the fact that in the method of mixing and grinding materials, in which the grinding bodies and the crushed material are loaded into a rotating working container, where under the action of centrifugal forces they form a layer of crushed material and grinding bodies on the inner surface of the working container and are processed using a stationary or a rotating blade, while the grinding media is separated from the layer of material to be ground and the grinding media with at least one blade and directed to the wall of the working vessel, and the grinding the material by passing through the through grooves and / or holes in the blade, wherein the feed material passing through the through slots or holes of the blade, is displaced along the axis of rotation of the working capacity.

The essence of the proposed method is illustrated by drawings:

In FIG. 1 shows a motion diagram of the milled material and grinding bodies of the working vessel;

In FIG. 2 is a view A of the front surface of the blade of FIG. one;

In FIG. 3 shows a cross section BB of the blade of FIG. 2.

The method is as follows.

In a rotating working container 1, which can be made in the form of a cylindrical, conical or cylindrical-conical bowl (Fig. 1), crushed material 2 and grinding bodies 3 are loaded. During loading, crushed material 2 and grinding bodies 3 are partially mixed, forming a mixture of 4 crushed material 2 and grinding media 3. Under the action of centrifugal forces, mixture 4 of the crushed material 2 and grinding media 3 is pressed against the inner surface of the working container 1. Due to the friction forces between the inner surface of the working container 1, the mixture 4 is dispersed up to the rotation speed of the working tank 1.

When combined with the working capacity 1, the crushed material 2 and the grinding bodies 3 are under the influence of centrifugal forces, the value of which depends on the speed of the working capacity 1 and the thickness of the mixture layer 4 and can reach values comparable with the mechanical strength of the crushed material 2. In this case, the mixture layer 4 is compacted, and the crushed material 2 is partially destroyed under the action of normal stresses created in the mixture layer 4 by centrifugal forces. After this, the layer of the mixture 4, located on the inner surface of the working tank 1, is separated by a blade 5, which has through grooves 6 and / or holes 7 (Fig. 2). Since the width of the through grooves 6 and / or holes 7 is less than the smallest size of the grinding bodies 3, they move along the front surface of the blade 5, and the crushed material 2 passes through the through grooves 6 and / or holes 7 in the blade 5 and falls on the inner surface of the working containers 1, where a layer of crushed material 2 is formed. Grinding bodies 3 and large pieces of crushed material 2, the size of which is larger than the width of the through grooves 6 or holes 7, form a stream upon exiting the blade, which after the free flight stage inside the working container 1 falls onto a layer of crushed material 2, moving together with the inner surface of the working vessel 1. The crushed material 2 is intensively crushed under the impact of the flow of grinding media 3 under compression by centrifugal forces. In addition, when the layer of mixture 4 is divided into grinding bodies 3 and crushed material 2, intensive mixing of the crushed material 2 occurs if it consists of several (two or more ingredients). To increase the intensity of mixing of the crushed material 2 and reduce the phenomenon of overgrinding using through grooves 6 and / or holes 7 or other structural elements on the blade 5, the crushed material 2 passing through the through grooves 6 and / or holes 7 is shifted along the axis of rotation of the working vessel 1 , for example, due to the inclination of the side walls 8 of the through grooves 6 and / or holes 7 (Fig. 3). In addition, the displacement of the crushed material 2 along the axis of the working tank 1 allows you to remove the material from the zone of intensive processing and move it to the unloading zone. Processing of the material can be carried out in a rotating working container 1 with a stationary or rotating blade 5. The direction of rotation of the blade 5 can coincide with the direction of rotation of the working container 1, or the working container 1 and the blade 5 can rotate in different directions. The choice of the direction and speed of rotation of the blades 5 depends on the properties of the crushed material 2. To increase the intensity of grinding and mixing, the processing of the material inside the working tank 1 can be carried out with two or more blades 5, distributed both around the circumference of the working tank 1 and along its axis. The principle of operation of each of these blades is similar to the principle of operation of the blade 5 described above.

This method of mixing and grinding materials allows the processing of the crushed material 2 at a high level of compressive stresses arising in the layer of the mixture 4 and the layer of crushed material 2 under the action of centrifugal forces. In addition, the regulation of the rotational speed of the working vessel 1, the frequency and direction of rotation of the blade 5 allows you to adjust the level of impact of grinding media 3 on the layer of material to be crushed 2. This allows you to grind material with various physical and mechanical properties, dramatically reducing the level of overgrinding due to the selection of processing modes.

Reducing the processing time of grinding and mixing when using this method occurs due to an increase in the intensity of the impact on the crushed material 2, which is in a compressed state, as well as due to the repeated repetition of single processing cycles, the withdrawal of the crushed material 2 from the zone of intensive exposure and additional abrasion on the crushed material 2 with its joint movement with the grinding bodies 3 along the blade 5.

Experimental studies have shown a decrease in noise during grinding and mixing in comparison with traditional mills, as well as a significant reduction in wear on the inner surface of the working vessel 1.

Claims (2)

1. A method of mixing and grinding materials, in which the grinding bodies and the crushed material are loaded into a rotating working container, where under the action of centrifugal forces they form a layer of crushed material and grinding bodies on the inner surface of the working container, which is processed using a fixed or rotating blade, characterized the fact that the grinding media are separated from the layer of material to be ground and grinding bodies with at least one blade and directed to the wall of the working vessel, and the material to be ground is passed through the through grooves and / or holes in the blade. 2. The method according to p. 1, characterized in that the crushed material passing through the through grooves and / or holes of the blades, offset along the axis of rotation of the working container.

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