RU2462314C2 - Roll mill for loose materials - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to grinding cement initial stock, cement clinker and the like. Proposed mill comprises horizontal grinding table and set of rolls arranged to revolve about vertical shaft. Said set comprises several rolls coupled with vertical shaft via their appropriate bearings and shafts. Said rolls interact with grinding table to apply force to loose material. Every roll bearing is fitted radially on vertical shaft to take up resultant force applied to appropriate roll in grinding. Every said roll runs about axle articulated with vertical shaft by joint with turn center to allow free circular motion of the roll up and down in plane wherein roll axis line is located.

EFFECT: reduced load at bearing.

8 cl, 4 dwg

Description

The present invention relates to a roller mill for grinding dispersed material, such as cement feedstock, cement clinker, coal and other similar materials, comprising a mainly horizontal grinding table and a group of rolls rotating around a vertical shaft, this group comprising several rolls made with the possibility of rotation around its axis of the roll and connected by the roller bearing and the axis of the roll with a vertical shaft, and the group of rolls is configured to interact with the grinding table, kladyvaya pressure to the particulate material.

A roll mill of this type is known, for example, from UK Patent 601,299. This mill is designed so that the group of rolls rotates in one direction and the grinding table rotates in the opposite direction, which increases the productivity of the mill. According to the aforementioned patent publication, the rolls are connected to a vertical shaft by a connection similar to a crank mechanism, in which each roll is attached by a fixed crank protruding centrally in the roll. This publication does not examine in detail how the roller is mounted on a crank, but based on prior knowledge of the roller mills, this is most likely achieved using either a sliding bearing or a rolling bearing integrated in the roller itself. As follows from figure 1 and is defined in the introductory part, the reaction forces F _g.1 and F _g.2 , arising from the application of the grinding force F _g acting in the grinding zone between the roller and grinding table. In addition, the center of mass of each roll will occur gyroscopic moment M _gyro, enclosed in a plane including the center axis of the roll, and the gyroscopic moment will cause reaction forces F _gyro.1 and F _gyro.2, acting on the bearing roller. The magnitude of this gyroscopic moment and, consequently, the reaction forces depends on the moment of inertia of the roll and its rotation speed around its own axis, as well as on the speed of rotation of the group of rolls around the vertical shaft. As can be seen in FIG. 1, the reaction force F _gyro.2 and the reaction component F _g.2 caused by the grinding force will simultaneously affect the innermost part of the bearing, that is, the part that is closest to the vertical central shaft. Therefore, the total load applied to this part of the bearing can be quite substantial, leading to wear at an early stage and (or) destruction of the support.

The basis of the invention is the task of creating a roller mill, in which the aforementioned disadvantage is reduced.

This is achieved in a roller mill of the type mentioned in the introductory part, characterized in that each roller bearing along its entire length along the axis is located axially radially towards the vertical shaft, inside relative to the place of application of the resultant force acting during operation from the grinding zone on the corresponding roller .

As a result, the load on the entire bearing, and especially on its innermost part, is reduced, since the reactive forces associated with the gyroscopic moment and the grinding force exert a partial and mutually neutralizing effect along the entire axial length of the bearing.

In principle, the roller bearing may consist of any suitable bearings, and in the illustrated example embodiment it may consist of a sliding bearing arranged, for example, in a bearing housing with a closed cylindrical bearing shell in which the axis of the roller rotates. However, it is preferable that the roller bearing be made in the form of a housing comprising at least two rolling bearings. It is also preferred that the roller bearing includes an axial support.

Each axis of the roll is preferably connected to the vertical shaft by means of a swivel having a center of rotation, allowing free movement along the arc up and down in the plane in which the axial line of the axis of the roll lies. As a result, the gyroscopic moment will contribute to the grinding force acting on the dispersed material. The centerline of the vertical shaft does not necessarily lie in the plane in which the roll moves. To reduce the influence of shear stresses in the grinding zone, the roll is sometimes or often slightly inclined, that is, its center line does not always pass through the center line of the vertical shaft. As in the previously known roller mills, the roll axis itself can be fixed, but in order to maximize the contribution to the grinding force from the gyroscopic moment, it is preferable that the roll axis be rigidly bonded to the roll.

Preferably, the center of rotation of the swivel in the vertical plane is located below the horizontal plane in which the center of mass of the roll, the axis of the roll and the associated part of the swivel lies, so that the centrifugal force acting on the parts of the device during operation of the mill creates a torque relative to hinge and, therefore, the force directed downward in the direction of the grinding table.

In principle, the roller mill can be made with inclined axes of the rolls, for example with tilt angles in the range between 0 and 45 degrees to the horizontal level, so that in accordance with the aforementioned, the centrifugal force acting on each roller makes a positive contribution to the grinding pressure if the center of rotation of the swivel is located below the horizontal plane in which the center of mass of the roll lies, the axis of the roll and the associated part of the swivel. However, the disadvantage associated with the inclined axes of the rolls is that this reduces the contribution due to the action of the gyroscopic moment. Therefore, according to the invention, it is preferable that the axis of each roll is substantially horizontal.

Below the invention is described in more detail with reference to the accompanying drawings, which schematically shows:

figure 1 is a cross section of a known roller mill;

in figures 2 and 3 are two illustrative embodiments of the roller mill proposed in the present invention; and

figure 4 is a preferred embodiment of the roller mill proposed in the present invention.

In Figures 1-4, matching reference numbers are used for similar elements. All four figures show a section of a roll mill 1 containing a horizontal grinding table 3 and a group of rolls 4 interacting with it, of which only one roll is shown connected with a vertical shaft 5 around which it rotates.

In the roll mill shown in FIG. 1, the rolls 4 are mounted on their horizontal axes using a bearing 16, which includes two rolling bearings 16A and 16B, axially spaced on different sides relative to the resulting grinding force F _g acting on the roll from the grinding zone . As can be seen in FIG. 1, the rolling bearings 16A and 16B during the operation of the roller mill will be affected by the reactive forces F _g.1 and F _g.2 due to the grinding force F _g arising in the grinding zone between the roller and the grinding table, and the reaction forces forces F _giro.1 and F _giro.2 due to the gyroscopic moment M _gyro applied to the center of mass of the roll. As can be seen in figure 1, the rolling bearing 16B is loaded with a _crushing force reactive force F _giro.2 and a reactive component F _g.2 acting on one side, which is undesirable since it can lead to a sufficiently large load on this bearing, causing early wear (or) destruction of the bearing.

According to the invention, each bearing 16 is axially positioned internally with respect to the resulting force F _g acting on the roll 4 from the grinding zone, which reduces the load on the entire bearing 16 and especially on its innermost part, since the reactive forces associated with the gyroscopic moment and grinding force, have a partial and mutually neutralizing effect along the entire axial length of the bearing, as shown in figures 2-4.

In the embodiment shown in FIG. 2, the roll axis 6 is fixed in the same way as in FIG. 1 and is supported by a bearing 16 consisting of two rolling bearings 16A and 16B. The embodiment shown in FIG. 2 differs from FIG. 1 in that the roller 4 is made with a bearing housing 9 elongated axially to the vertical shaft 5 from the inside of the roller 4. As a result, both the rolling bearing 16A and the rolling bearing 16B along the axis are located relative to the resulting force F _g acting on the roll 4. The axis 6 of the roll is also provided with a flange 16C that serves as an axially supporting surface for the bearing.

In the embodiment shown in FIG. 3, the roll axis 6 is rigidly bonded to the roll 4 and provided with a flange 16C that serves as an axial bearing surface for the bearing.

A preferred embodiment of the invention is shown in FIG. In this embodiment, each axis 6 of the roll is connected to the vertical shaft 5 by a swivel 7 having a rotation center 7a, which allows the roll to rotate freely up and down in the plane in which the axial line of the roll axis lies. As a result, the gyroscopic moment will contribute to the grinding force F _g acting on the dispersed material. As in FIG. 3, the axis of the roll is also rigidly bonded to the roll 4, so that it rotates with it, contributing to the grinding force created by the gyroscopic moment. When viewed in a vertical plane, the center of rotation 7a of the swivel joint 7 is also located below the horizontal plane, in which lies the center 8 of the mass of the roll 4, the axis 6 of the roll and the associated part of the hinge, so that the centrifugal force acting during the operation of the mill on the roll 4, axis 6 of the roll and the associated part of the hinge will also create a torque relative to the hinge 7 and, therefore, the downward component of the grinding force F _g .

Claims (8)

1. Roller mill (1) for grinding dispersed material, such as feed cement, cement clinker, coal and other similar materials, comprising a substantially horizontal grinding table (3) and a group of rolls rotatably mounted around a vertical shaft ( 5), and this group includes several rolls (4), rotatable around the respective axis of the roll and connected through the bearing (16) of the roll and the axis (6) of the roll with a vertical shaft (5), and this group of rolls (4) is made with the possibility of inter action with the grinding table (3) for applying pressure to the dispersed material, characterized in that each bearing (16) of the roll along its entire axial extent is located axially radially towards the vertical shaft (5), inside relative to the place of application of the resulting force when working from the grinding zone to the corresponding roll, each axis (6) of the roll connected to the vertical shaft (5) by a swivel (7) with a rotation center (7a), which allows free arcuate movement up and down plane in which the center line of the roll axis. 2. Roller mill according to claim 1, characterized in that the roller bearing (16) is made in the form of a bearing housing (9) containing at least two rolling bearings (16A, 16B). 3. Roller mill according to claim 2, characterized in that the roller bearing (16) comprises an axial support (16C). 4. The roll mill according to claim 1, characterized in that the center (7a) of rotation of the swivel (7) in the vertical plane is located below the horizontal plane in which the center (8) of the masses of the roll (4), the axis (6) of the roll lie associated parts of the swivel. 5. The roll mill according to claim 4, characterized in that the axis (6) of the roll is rigidly bonded to the roll (4). 6. The roll mill according to claim 1, characterized in that the axis (6) of the roll for each roll (4) is generally horizontal. 7. The roll mill according to claim 1, characterized in that the axis (6) of the roll for each roll (4) has an inclination to a horizontal level of 0 to 45 °. 8. Roller mill according to claim 1, characterized in that each roller bearing (16) is located between the corresponding roller (4) and the vertical shaft (5).

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