JPS5817849A - Ball mill - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ball mill for pulverizing coal into pulverized coal.
This invention relates to a ball mill that can prevent vibrations caused by the balls of a K-ball mill.

In recent years, in Japan, due to the tight supply of heavy oil, in order to correct the dependence on oil, there has been a shift from traditional heavy oil-burning to coal-fired fuel. A power plant is being built.

However, since coal fuel has poor combustibility compared to petroleum fuel, attempts have been made to improve the combustibility by pulverizing coal into pulverized coal using a ball mill, tube mill, roller mill, or the like.

For example, in a ball mill, as shown in the m1 diagram, the coal feeding pipe 2
0. Coal crushing section 30. Power transmission part 40° classifier 50% pulverized coal outlet pipe 60. It is composed of a foreign matter outlet TO and a conveying air inlet 80.

As shown by the arrow in Coal Works Figure 1, the mill is being used 10
Coal is supplied to the inside of the coal crushing section 30 as shown by arrow B from the upper part of the coal feed pipe 20 located in the center of the coal.

The coal crushing section 30 is connected to a power transmission section 40, and has a rotating lower ring 11, on which a plurality of balls 12 that revolve and rotate, and a spring or nitrogen (N) gas compressor mounted on the lower ring 11. It consists of an upper ring 14 which is pressurized by a cylinder 13 and which is fixed at T.

The supplied coal indicated by the arrow B mentioned above is pulverized by the lower ring 11 and the balls 12 in the pulverizing section 30, and is discharged to the outside of the pulverizing section 30 as indicated by the arrow C.

This pulverized coal is blown up through the housing 10 by the conveying air from the conveying air 80 as shown by the arrow, and is fed into the classifier sO as shown by the arrow E.

The coal fed into the classifier 50 is separated into pulverized coal and coarse coal, and the pulverized coal is transferred to the classifier 50 as shown by arrow F.
From the outlet pipe 60 to the burner part (not shown), the coarse coal is separated by specific gravity as shown by the arrow G, and is then transferred to the coarse coal discharge port 51 at the bottom of the classifier SO, or again to the inside a of the coal crushing part 30 as shown by the arrow B. - and crushed into pulverized coal.

Note that foreign substances such as metals and rocks contained in the coal do not pass through the coal crushing section 30 and are crushed, so they fall from the foreign substance discharge lower 0 to the outside of the mill housing 10 and are separated and discharged.

Ball mills such as those described above are used, and this type of ball mill has excellent fine pulverization performance and consumes less power than mills such as chip mills and roller mills, and the crushing part 30 rotates. Although there is an advantage that the I/O section is separated and the equipment is easy to maintain and manage, there is a disadvantage that vibration is large.

Considering the reason why ball mills have large vibrations in comparison with roller mills, in ball mills, the rotation of the lower grinding ring causes the balls 12 placed thereon to rotate and revolve, whereas in p-Raral, the balls of the ball mill There is a big difference in that the 4-Raha orbital delay, which corresponds to 4-Raha, is restricted and only rotation is performed. That is, in a ball mill, since the plurality of beers 12 perform irregular revolving motion, collision loads between the balls, eccentric loads, etc. occur, and the rotating shaft 1. Lower crushing ring 11. The crushing part 3o, which consists of the balls 12 and the upper crushing ring 14, vibrates at the natural frequency of the system, but since the orbital movement of the ν-ra is restrained in the outer mill, the above-mentioned impact load does not occur and vibrations occur. Although it is small, it has the disadvantage of high power consumption.Also, a chain ring is fitted into the ball of the ball mill to reduce collisions between the balls 12.

There is a type of ball that restricts the relative interlocking of the balls to perform regular orbital motion. However, the distance between the nine balls placed in a predetermined position is extremely small, and the chain ring is extremely thin, so there is a high risk of breakage due to the load generated during operation. Since the rotation movement of 19 meters is restrained between the shaped rings, the wear of the ball becomes localized and the life of the ball is shortened.

The present invention attempts to overcome these conventional deficiencies.
The purpose is to reduce the vibration of the mail mill,
It also prevents local wear of the ball itself. That's what you're trying to get with a ball mill.

In short, the present invention provides a recess for accommodating the crushed beer in either the upper crushing ring or the lower crushing ring, so that the rotational movement of the crushing balls is not restricted, but is caused to rotate regularly.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

Figure 2 is a vertical sectional view showing the overall configuration of the crushing section 30, and the first
A rotary shaft 19 connected to the reducer of the power transmission section 4o in the figure; a rotary table 2. Fixed and rotating lower grinding ring 11. Multiple balls 12. Upper crushing ring 14 that presses the balls
and a compression cylinder 13v. A material to be crushed, such as coal, is fed between a lower crushing ring 11, a ball 12, and an upper crushing ring 14, and is crushed into pulverized coal.

FIG. 3 is a plan view of the lower crushing ring 11 taken along the line X-X in FIG. be. If the balls 12 are placed in each of the recesses 3 as shown in Fig. 4, K will restrain collisions and relative movements of the balls 12 with each other as the lower grinding ring 110 rotates, and will allow regular orbital movement with a fixed arrangement. I tried to make them do this. This is K
Therefore, the rotational movement of the gill 12 can be prevented from being restricted, reducing the collision load between the balls and the eccentric load due to relative movement, reducing the vibrations caused by local wear of the ball 120. Ball life can also be further improved.

The ones in Figures 5 and 6 are other fruit 1! ffAM is shown and corresponds to FIG.

The difference from the one in Fig. 4 is that in the one in Fig. 4, a groove s is provided in the lower crushing ring 11, and in the one in Fig. 5, a recess 3 is provided in the upper crushing ring 141C. It is something.

In the one shown in FIG. 5, only the rotational movement of the ball 12 is free, and the orbital movement is restrained, so that no eccentric load is generated and there is an effect of further reducing vibration l.

In the one shown in FIG. 6, the lower crushing ring IIK has a recess 3 drilled therein, and the member 4 is attached by welding to the skin, and the other explanations are the same as those in FIG. 4.

The one shown in #I6 is useful for improving existing ball mills because it is only necessary to attach member 4.

The modification period and cost are short, and vibration can be reduced.

In addition, in the case of FIG. 6, a member 4' having a recess 3 bored in the lower crushing ring 11 and a jointed member will be described, but this member 4 may be attached to the upper crushing ring 14.

According to the present invention, by freeing the rotational motion of the balls and integrating their orbital motion with the rotational motion of a restraining or crushing ring, impact loads and eccentric loads that occur due to collisions and relative motion between the balls can be reduced. By reducing vibration caused by these loads and preventing local wear of the balls, continuous operation time can be improved.

[Brief explanation of the drawing]

Figure 1 shows the overall structure of the C-Rumill and is a specific vertical cross-sectional view, Figures 2 to 6 are comparative views showing the implementation of the present invention, and Figure 2 is an enlarged view of the crushing section in Figure 1. Detailed drawing. 3 is a plan view taken along the line X-X1iK in FIG. 2, FIG. 4 is a sectional view taken along the line Y--Y in FIG. 3, and FIGS. 5 and 6 are sectional views showing other embodiments. 3... depression, 4... member, 11...
... Lower crushing ring, 12 ... Ball, 14
・・・・・・Upper ring s2 figure W, 3 figure

Claims (1)

[Claims] A ball is interposed between an upper crushing ring and a lower crushing ring, and coal is crushed by the rotation and revolution of the ball due to the rotation of the crushing ring, and the crushing ring is provided with a weight to accommodate the balls, and the distance between the balls is adjusted. Ball milk that is regulated and characterized by