RU2381071C1 - Centrifugal mill - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed centrifugal mill comprises vertical cylindrical housing with intake and discharge bins, coaxial rotor accommodated inside said housing and incorporating milling bodies representing free-running rollers. Height of one or several rollers of a set is selected to make rollers joint height unequal between rollers of the other sets.

EFFECT: uniform load on milling bodies.

3 cl, 2 dwg

Description

The invention relates to devices for grinding materials and can be used in the production of powder materials to obtain a product with a given dispersion in the pharmacological and perfume industry for grinding plant materials, as well as in the construction, chemical and mining industries for grinding solid materials.

Known roller centrifugal mill containing a cylindrical body with nozzles for input and output of the processed material, in which a drive shaft with a separator holding grinding media is coaxially mounted. The separator is made in the form of plates mounted on a drive shaft in a spiral with the possibility of playing the role of a spiral fan, and having holes on the edges facing the cylindrical body for fixing grinding media, and in the area of the outlet pipe the mill is additionally equipped with an unloading disk (RF Patent No. 2252577 MPK8 V02S 15/08, published on 05/20/2005).

The disadvantages of this device are the presence in the central part of the housing of free space through which the passage of non-fragmented material is possible, as well as the limited possibility of using plates mounted on the drive shaft as a fan, since different materials require different speeds of rotation of the separator and the movement of grinding media , and therefore, at low speeds, the separator will not be able to act as a fan, and it is extremely difficult to extract from the mill from elchenny material. In addition, the device does not provide for the possibility of dosing the feed of the crushed material to the grinding bodies, which creates an uneven load on the grinding bodies and leads to uneven wear of the grinding bodies and the walls of the housing, and also leads to heterogeneity of the crushed material.

The closest solution selected for the prototype is a centrifugal mill containing a vertical cylindrical housing with loading and unloading nozzles, a rotor with a separator coaxially mounted in the housing, in the blind radial channels of which grinding bodies are placed in the form of a package of flat, identical discs not interconnected among themselves. The grinding process in this mill is carried out due to the movement of grinding media along the inner cylindrical surface of the housing and the destruction of the grinding material in the contact zone of the grinding media with the housing (RF Patent No. 2110327, IPC8 V02C 15/08, publ. 05/10/98).

The disadvantage of this device is the excessive wear of both grinding media and the inner surface of the cylindrical body, which leads to a change in geometry and, as a consequence, to a change in the initial parameters of grinding of raw materials. This is due to the symmetrical arrangement of the grinding media around the circumference of the rotor and the performance of the grinding media of the same size in height, and the joints between the rollers in all sets are on the same level. In addition, the metal particles obtained as a result of wear of the mill parts get into the crushed material and pollute it, which is completely unacceptable when grinding raw materials in the pharmaceutical, perfumery, and chemical industries.

The disadvantage of this device is the uneven load on the grinding media, which also leads to uneven wear of the grinding media and the walls of the housing and the heterogeneity of the crushed material: it is not possible to separate particles of crushed material of acceptable size from larger particles during the grinding of the material.

Technical problems to be solved by the invention:

- improving the design of the device, providing for the reduction of wear of grinding media and a cylindrical body;

- providing a more uniform load on the grinding bodies;

- the ability to separate particles of crushed material of acceptable size from larger particles in the process of grinding material.

The tasks are solved as follows.

The inventive centrifugal mill comprises a vertical cylindrical housing with loading and unloading bins, a rotor coaxially mounted in the housing with grinding media in the form of several sets of freely rotating rollers. The height of one or more rollers in each set is selected from the condition of mismatch of the levels of joints between the rollers in other sets.

The rotor is made with upper and lower flanges with windows through which the crushed material is fed to each set of freely rotating rollers.

Due to the fact that the mill is equipped with a system of adjustable exhaust ventilation, the air flow rate created by the ventilation system and passing between the cylindrical body and the rotor is selected to allow particles of crushed material of acceptable size to soar in the air stream. In the grinding process, particles of crushed material of permissible particle size are separated from larger particles and particles of crushed material of permissible particle size are removed from the grinding zone to an unloading device.

In comparison with the prototype of the claimed technical solution has the following significant distinguishing features:

- in each set, the height of one or more rollers is selected from the condition of mismatch of the levels of joints between the rollers in other sets;

- the rotor is made with upper and lower flanges with windows through which the crushed material is fed to each set of freely rotating rollers;

- the mill is equipped with a controlled exhaust ventilation system, and the air flow rate created by the ventilation system between the cylindrical body and the rotor is selected to ensure that particles of crushed material of acceptable size are soared in the air stream to separate them from larger particles and the particles of crushed material of acceptable size are removed from the grinding zone to the unloading device.

The analysis of the prior art, including a search by patent and scientific and technical sources of information, made it possible to establish that technical solutions characterized by features identical to all the essential features claimed were not found, which allows us to conclude that the proposed solution meets the criterion of "novelty."

The set of essential distinguishing features allows us to solve the problem and to conclude that the proposed technical solution meets the criterion of "inventive step".

Figure 1 presents a longitudinal section of the mill on BB.

Figure 2 presents a cross section of the mill along aa.

The centrifugal mill comprises a cylindrical housing 1, in which a rotor 2 mounted in the housing 1 is coaxially located with the upper and lower flanges 3 and 4. Between the flanges 3 and 4, several vertical axes 5 are fixed with sets of grinding bodies 6 in the form of freely rotating rollers 7 mounted one above another with a joint 8 between the rollers 7. The rollers 7 are made of various heights. Windows 9 and 10 are made in the upper and lower flanges 3 and 4 of the rotor 2, dispensing the supply of crushed material to each set of grinding bodies 6 and ensuring the discharge of crushed material. A loading hopper 11 is installed in the upper part of the housing 1, and an unloading hopper 12 with a removable bottom 13 is installed in the lower part, hermetically connected to the housing 1. An exhaust fan 14 with an adjustable capacity is connected to the upper part of the hopper 11.

The mill operates as follows.

When the mill is assembled in the rotor 2 in each of the sets 6, differently high rollers 7 are installed on the axis 5, and the height of the rollers is selected so that the levels of the joints 8 between the rollers in all sets of rollers do not coincide. This makes it possible to distribute the load from the rollers 7 to the housing 1, reduce its wear and increase durability.

After starting the mill, the material intended for grinding through the feed hopper 11 is fed to the upper flange 3 of the rotating rotor 2 and through the metering windows 9 it enters the space between adjacent sets of grinding bodies 6 with uneven rollers 7. The rotating material and the grinding rotor with rollers are pressed against the inner wall of the housing 1 and crushed into smaller particles. The performance of the exhaust fan 14 is set so that the air flow rate generated by the ventilation system and passing between the cylindrical body 1 and the rotor 2 ensures that particles of crushed material of acceptable size are soared in the air stream, separating them from larger particles that are in the process of grinding. In this case, the soaking particles of crushed material of an acceptable size are carried out by the air flow from the grinding zone to the discharge hopper 12 with a removable bottom 13. Once in the discharge hopper 12, the air flow rate decreases sharply, the particles of ground material fall out of the air stream, settle on the bottom 13 and then are removed from the hopper.

A prototype centrifugal mill is designed, manufactured and tested at the experimental base of the applicants, the city of Novosibirsk.

Claims (3)

1. A centrifugal mill containing a vertical cylindrical housing with loading and unloading bins, a rotor coaxially mounted in the housing with grinding media in the form of several sets of freely rotating rollers, characterized in that in each set the height of one or more rollers is selected from the condition of mismatch of the levels of joints between rollers in other sets. 2. The centrifugal mill according to claim 1, characterized in that the rotor is made with upper and lower flanges with windows through which the material to be crushed is fed to each set of freely rotating rollers. 3. The centrifugal mill according to claim 1, characterized in that it is equipped with a controlled exhaust ventilation system, and the air flow rate generated by the ventilation system between the cylindrical body and the rotor is selected to allow particles of crushed material of permissible particle size to soar in order to separate them from more large particles and the removal of particles of crushed material of acceptable size from the grinding zone to the unloading device.

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