JPH0327266B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a grinding table rotatable about a vertical axis and at least one grinding table rotatable about a generally horizontal fixed shaft and pressed downwardly relative to the grinding table. The present invention relates to a vertical roller flour mill having two grinding rollers. The above-mentioned type of flour mill will be explained below.

In conventional flour mills of the above type, the rollers are aligned with the grinding path of the grinding table, that is, the tangent of the grinding roller and the tangent of the annular grinding path on the grinding table are parallel at the contact point between the grinding roller and the grinding table. The roller shaft was placed within the axial plane of the table.

Theoretically, it is not possible for large axial forces to develop on the grinding rollers due to the pressure created by the layer of raw material being ground between the grinding rollers and the grinding path. However, experience has shown that the grinding rollers are actually subjected to large outward forces. This axial force causes a considerable load on the grinding roller bearings, thereby shortening the life of the grinding roller bearings. It is understood that the above phenomenon is due to a fairly large difference between the thickness of the layer of raw material passing under the roller and before being crushed, and the thickness of the layer of crushed raw material under the roller. Ivy. For the above reason, the pressure center point of the raw material layer against the crushing roller is not located vertically below the crushing roller, but is located slightly forward of the above position on the front side of the crushing roller when viewed in the rotational direction of the crushing table. There is. As a result, the tangent to the grinding table at the center of pressure position in front of the grinding roller and the direction of the grinding pressure are not perpendicular to the table axis passing through the center of the roller. The roller is thus subjected to a force having an axial component from the raw material.

It is an object of the invention to eliminate or at least reduce the above-mentioned outward axial forces on roller bearings.

According to the invention, the invention comprises a grinding table rotatable about a vertical axis and at least one grinding roller rotatably mounted via bearings around a generally horizontal fixed shaft, the grinding roller being rotatably mounted around a generally horizontal fixed shaft. In a vertical roller mill, the inner end is fixedly attached to a fixed frame and the outer end of the fixed shaft is pivotally connected to means for pressing the grinding roller downwardly towards the grinding table, When viewed from above, the grinding roller is arranged so that the front side of the grinding roller, which faces the raw material approaching on the grinding path, is closer to the grinding table axis than the rear side of the grinding roller. The axis of the grinding roller is arranged at an angle of 1° to 5° on a horizontal plane with respect to the axial plane of the grinding table passing through the center of the roller.

According to the configuration in which the axis of the crushing roller is inclined at an appropriate angle of 1° to 5° with respect to the radial direction of the crushing table passing through the center of the crushing roller as described above, the axial center of the crushing roller is located on the front side of the crushing roller. The crushing pressure from the point of application of the crushing pressure can act in a direction substantially exactly perpendicular to the axial direction of the crushing roller, and does not exert any acting force in the axial direction of the crushing roller. Therefore, almost no axial force is applied to the bearing of the crushing roller, so that the life of the bearing can be greatly extended, and the reliability of the apparatus can also be improved.

In the following, the invention will be explained in more detail by referring to an example of a flour mill according to the invention with reference to the drawings.

FIG. 1 is a diagrammatic side view of a portion of a flour mill, a portion of which is shown in vertical section.

FIG. 2 is a plan view of the same mill, and FIG. 3 is an enlarged detail of the left-hand portion of FIG.

The illustrated flour mill has a grinding table 1 which is rotatable about a vertical axis and which is held and driven by a device inside a housing 2. In this example, three crushing rollers 3 are placed on the crushing table 1 and roll to crush a layered raw material (not shown) placed on the crushing table 1. Each roller 3 is mounted on a fixed shaft 4. The fixed shaft 4 is mounted together with the shafts of the other rollers on a common central frame 5.

The shaft 4 can be attached to the frame 5 in various ways. For example, it can be attached by a flange 6 on each shaft and a corresponding flange 7 on the frame 5 as shown.

A bracket 8 is pivotally attached to the outer end of each shaft 4, and a drawbar 9 is mounted on this bracket.
is mounted and presses the rollers downwardly towards the grinding table 1 by means of, for example, a hydraulic cylinder pivotally mounted on a bracket 11 fixed to the base of the mill.

The shaft 4 is moved in the direction of rotation of the grinding table, for example as shown in FIG. is being prevented from doing so.

The raw material to be crushed is supplied to the center of the grinding table 1 through an opening 13 provided at the center of the frame 5. The dam ring 14 serves to determine the thickness of the raw material layer on the grinding table 1.

As can be seen in FIGS. 1 and 2, and as will be explained in more detail in connection with FIG. The front of the mill is closer to the mill axis than the rear.

In FIG. 3, 16 is the vertical axis of the mill (ie, the axis of rotation of the table 1), 17 is the center of the grinding roller, and 18 is the axial plane defined by the mill shaft 16 and the center 17 of the roller. As can be seen, the axis 19 of the grinding roller is inclined in the horizontal plane slightly with respect to the surface 18 and, viewed from above, in a direction opposite to the direction of rotation 15 of the grinding table. This inclination makes the tip of each shaft 4 supporting the rollers
It can be provided by being inclined relative to the inner part attached to the frame.

20 indicates the point of action of the crushing pressure on the crushing roller. The magnitude of the angle a can be determined such that the tangent to the grinding table at point 20 is perpendicular to the roller axis 19, and a range of α=1° to 5° is practically appropriate. As a result, since the crushing pressure exists on a plane perpendicular to the roller axis 19, the crushing pressure does not act on the crushing roller in the axial direction. Thus, the axial forces in the roller bearing are reduced compared to a roller having its axis inside the surface 18.

The aforementioned reduction in the axial force of the grinding rollers is not limited to rollers rolling on a horizontal grinding path, but is also effective for grinding paths that are slightly inclined downward toward the vertical axis of the mill. be.

[Brief explanation of drawings]

FIG. 1 is a side view showing a part of the flour mill. FIG. 2 is a plan view of the flour mill shown in FIG. 1. FIG. 3 is an enlarged detailed view of a portion of FIG. 2. 1...Crushing table, 3...Crushing roller, 4...
...Shaft, 16...Crushing table axis.

Claims (1)

[Claims] 1. A grinding table rotatable about a vertical axis and at least one grinding roller rotatably mounted via a bearing around a generally horizontal fixed shaft, the fixed shaft In a vertical roller mill, the inner end of the shaft is fixedly attached to a fixed frame and the outer end of the fixed shaft is pivotally connected to means for pressing the grinding roller downwardly towards the grinding table. , when viewed from above, the grinding roller is arranged such that the front side of the grinding roller facing the approaching raw material on the grinding path is closer to the grinding table axis than the rear side of the grinding roller. A vertical roller flour mill characterized in that the axis of the grinding roller is arranged at an angle of 1° to 5° on a horizontal plane with respect to the axis of the grinding table passing through the center of the grinding roller.