SU1724361A1 - Method of fine grinding materials in planetary mill, device for realization of the method - Google Patents

Abstract

Use: fine and ultrafine grinding and activation of materials. The material is fed to the bottom of the grinding drums of a planetary mill and crushed in them in the upstream layer, and then additionally crushed in the downward layer between the mill body and the outer walls of the drums, which are mounted on the cage with the possibility of radial movement. The lids of the drums are made with discharge openings, the bottoms are solid, and the loading nozzles are installed relative to the latter with a gap. 2 sec. and 1 z.p. f-ly, 2 ill. & J

Description

The invention relates to the fine and ultrafine grinding of materials, their activation and can be used in the mining, chemical, abrasive, food, electronic industry and other industries.

Known methods of grinding in drum mills by mechanical destruction of the material by grinding bodies.

Planetary mills and a method of grinding material in them are known, containing vertically arranged grinding drums driven by the carrier through the toothed rolling surfaces. Grinding in them is carried out by mechanical destruction of the material by grinding bodies in a centrifugal field of forces created by the rotation of the grinding

drums with grinding bodies around a common axis.

A planetary continuous mill is known.

The disadvantages of the known devices are the low degree of grinding, due to the fact that grinding is carried out in one stage and only in the grinding drums when the material passes through them from top to bottom.

The purpose of the invention is to increase the degree of grinding.

The goal is achieved by feeding the material to the bottom of each drum, grinding the material during the upward layer of material in each drum, and prior to unloading the material is directed from the top of each drum to the mill body and additionally grinding.

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ABOUT

with a descending layer between the outer wall of each drum and the mill housing.

The grinding drums of the planetary mill are mounted on the carrier with the possibility of radial movement, the covers of the drums are made with discharge openings, the bottoms are solid, and the loading nozzles are installed with a gap relative to the latter.

FIG. 1 shows a planetary mill, general view; in fig. 2 is a sectional view in FIG. one.

The planetary mill consists of a cylindrical body 1, a drive shaft 2 with a pulley 3, drove 4, grinding drums 5, loading nozzles 6-8, discharge hopper 9 and frame 10.

The drive hollow shaft 2 is installed inside the housing 1 along its central axis and is fixed in bearings on the upper 11 and lower 12 end covers of the housing 1.

The carrier 4 is rigidly fixed on the drive shaft 2 and made with radial grooves 13. The grinding drums 5 are fixed in bearing assemblies 14 and 15, which are mounted so that the carrier 4 can move in the grooves 13. Boot nozzles 6-8 are made in the form of a rectangular pipeline, vertical portions of which 6 and 8 are located inside the drive shaft 2 and the grinding drums 5, respectively, and their connecting portions 7 are made in the form of a telescopic connection.

The boot nozzles 7 are installed on the axis of the grinding drums 5 cantilever with a gap in relation to their bottom end caps 16.

On the top end caps 17 of the grinding drums 5 and the bottom end cap 12 of the housing 1 are provided with annular discharge openings 18 and 19, respectively.

On the lower end covers 16 of the grinding drums 5 under the loading nozzles 8, as well as inside the drive shaft 2, cone distributors 20 and 21, respectively, are installed at the junction of the loading nozzles 6 and 7.

The housing 1 with the discharge hopper 9 is installed on the support frame 10.

Planetary mill works as follows.

The torque from the power source is transmitted through the pulley 3, the drive shaft 2 and the carrier 4 to the grinding drums 5, which under the action of centrifugal forces move in the grooves 13 of the carrier 4 in the radial direction.

The outer surface of the grinding drums 5 engages in frictional engagement with the inner surface of the housing 1 and the drums 5 begin to rotate around their own axes, making a planetary motion.

The source material through the loading nozzles 6-8 under the action of gravitational and centrifugal forces is supplied to the lower end face cover 16 of the grinding drums 5. The cone distributors 21 and 20 contribute to its uniform distribution. From the cover 16 the material moves to the inner wall of the molar drums 5 in the direction of action centrifugal forces arising from the rotation of the drums 5. At the same time, the speed of rotation of the carrier 4 in idle mode of the planetary mill should provide

0 the location of the grinding bodies on the inner side (vertical) cavity of the drums and reliable frictional engagement of the drums 5 with the inner cylindrical surface of the housing 1.

5 On the inner cylindrical surface of the grinding drums 5, the material undergoes intensive grinding as the balls interact with each other and the vertical wall of the grinding drum by 5. During the grinding process, as the size of the material decreases, its bulk density decreases and under the action of the newly loaded material having a large mass, fine material, moving upward, it is discharged through circular holes 18 into the mill housing. Under the action of centrifugal force generated by the carrier 4, the material is thrown onto the inner cylindrical surface.

0 of the housing 1 and is subjected to additional grinding between the inner and outer cylindrical surfaces of the housing 1 and the grinding drums 5, respectively. The grinding between the surfaces proceeds in a layer of material moving in a downward spiral on the inner cylindrical surface of the housing 1. At the same time, the material is subjected to repeated intensive the compression of the planetary forces (rolling) inside the casing 1 by the grinding drums 5. The layer of material, besides sharp compression, is also subjected to considerable contact In this case, the particles, separately and in the composition of the layer, move relative to each other, interact with each other, and abrade each other under high pressure drums. Finely ground particles complete the spiral movement in the discharge bunker 9 of the planetary mill. The grinding process is over.

The operation of the planetary mill is controlled by varying the frequency of rotation of the carrier and the feed of the material. An increase in the rate of movement of the material in the working areas of the planetary mill is possible by blowing it with air in the direction of movement of the material.

Specific example of a planetary mill: Case diameter, mm520 Case height, mm450 Diameter of grinding drums200 Length of grinding drums 250 Number of grinding drums2 Droplet rotation frequency, 1 / min 600-700 Size of initial material, mm 5-6 10-20 Dimensions, mm:

length 730

width 730

height850

Installed on

power, kW3,0

Weight, kg200

Example. The planetary mill before loading the material is brought to idle mode, corresponding to the carrier frequency, not less than 600 1 / min. The ball loading of the grinding drums is 20-25% of their volume. The diameter of the balls is (15 ... 20).

Synthetic ruby is subjected to grinding with a particle size of not more than (3 ... 4) m.

The source material through the loading nozzles falls to the bottom of the grinding drums, where it is thrown onto the walls of the drum by the action of centrifugal forces and exposed to intense balls. Grinding in the grinding drums occurs when the balls interact with each other and the walls of the drums. In this case, both the balls and the ground material are in the field of centrifugal forces arising from the rotation of the grinding drums around their own axis and the axis of the planetary mill.

In the process of grinding with a decrease in the size of the material, and, accordingly, of its bulk mass, the material, under the action of the newly loaded material having a large mass, begins to move along

the inner working surface of the grinding drums in an upward spiral and is unloaded through the circular discharge openings of the grinding drums under the action of centrifugal forces. In the mill housing, the material that has passed the grinding drums is thrown off by the centrifugal force generated by the carrier on the walls, forming a layer that is subjected to additional grinding by the grinding drums rolling inside the housing. The movement of the material along the inner surface of the body of the planetary machine occurs along the downward spiral under the action of multiple

periodic sealing between the cylindrical surfaces of the housing and the grinding drums. Here, grinding occurs in the process of mutual movement of particles between themselves during intensive compaction, i.e. mutual abrasion occurs, which allows to achieve the effect of fine grinding. The ground material is discharged at the end of the cylindrical part of the mill body. Speed

the movement of the material in the planetary mill at a constant speed of rotation of the carrier is controlled by the feed of the source material.

If necessary, the speed of movement

The material in the planetary mill can be increased by blowing air in the direction of movement of the material.

Claims (3)

Claim 1. Method for fine grinding of materials in a planetary mill, including feeding the material into the grinding drums of the latter, grinding it into them and unloading the crushed material, is different and, in order to increase the degree of grinding, the material is fed directly to the bottom the drums and after grinding therein, additional grinding is performed between the outer walls of the drums and the mill casing with the subsequent unloading of the crushed material. 2. The method according to claim 1, wherein the grinding of material in the drums is carried out in the upstream layer thereof, and additional grinding in the downward layer of the material. 3. A device for fine grinding of materials in a planetary mill, containing a cylindrical body, grinding drums with a lid and a bottom mounted on it in a vdil, which are in frictional engagement with the lateral surface of the body; a side located on top of the axis of each drum and connected to a loading unit, and a discharge bunker located under the body, characterized in that the drums are mounted on the device with the possibility of radial movement, the drum covers are made with discharge openings, the bottoms are solid, and the loading nozzles installed with a gap relative to the latter. USG . - / FIG. 2