JPS6082146A - Operation of roller 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 provides a grinding table that rotates around a vertical axis.
The present invention relates to a method of operating a roller mill that crushes raw materials under pressure between an annular groove with a substantially arcuate cross section provided in a surface and an outer circumferential surface of a crushing roller rotatably attached to an oscillating roller shaft. The present invention relates to an operating method that allows control of throughput and vibration amount to be performed during operation.

In recent years, efforts have been made to use highly efficient roller mills to crush cement clinker, blast furnace slag, etc. This kind of roller mill has the advantage of high processing capacity because it actively crushes the raw material caught between the crushing table supported on the machine base and the crushing roller by the squeezing force of both. Cement l as above
- When pulverizing IWi materials, coal, etc., there are cases where it is necessary to adjust the processing capacity of the roller mill in accordance with the processing capacity of post-process equipment such as a kiln or boiler.

Generally, in conventional roller mills, such processing capacity is adjusted by the amount of raw material supplied, but in roller mills, as mentioned above, the raw material caught between the crushing roller and the crushing table is compressed. In order to prevent metal contact between the grinding roller and the grinding table, a stopper mechanism is provided to prevent the grinding roller from approaching the grinding table within a certain distance. If the supply amount of the 7 raw materials is made very small in accordance with the processing capacity of 1, the stopper mechanism will work and it will not be possible to obtain the required product particle size i3. In the case of conventional roller mills, the adjustment range for the throughput is relatively narrow, so if the throughput is controlled beyond the adjustment range, there are problems such as poor pulverization and the inability to obtain an appropriate particle size distribution. .

In addition, in the case of a roller mill, as mentioned above, the raw material is actively crushed under pressure, and unlike a ball mill, the raw material is not crushed by collision grinding between the crushing medium and the raw material, so it is more expensive than a ball mill etc. The fact that the swing ff1l+ is large [
This is an obstacle in using l-ramyl for grinding cement clinker, blast furnace slag, etc.

The causes of vibrations in roller mills as mentioned above, especially those caused by the vibrations of the T51 crushing roller, can be divided into two types: those caused by the if degree of the raw material or its changes, and those caused by the degree of IF of the raw material, and those caused by the vibration of the crushing roller due to the lIh of the crushed raw material. 1', (There is a so-called automatic vibration that occurs in the ¥ direction, and according to experiments conducted by the present inventor, such self-excited vibration is caused by controlling the flow of the raw material powder in the radial direction on the grinding table 1-. It has been found that this can be significantly reduced.

First, the general structure of a roller mill to which the present invention can be applied will be explained with reference to FIGS. 1 to 4, and the causes of self-excited vibration will be explained.

FIG. 1 is a side sectional view showing the structure of a conventional general roller mill. In the figure, 1 is a crushing table, which is actively rotated around a vertical shaft 2 by a drive source such as a motor (not shown). Ru.

An annular groove 3 centered on the vertical axis 2 is formed on the upper surface of the crushing table 1, and the annular groove 3 has an arcuate cross-sectional shape concave downward as shown in the figure.

Further, on the upper part of the crushing table 1, a set of crushing rollers 5° and 5to whose outer circumferential surface 4 faces the annular groove 3 are arranged in the direction of the annular groove 3 through a gap 6 between them and the annular groove 3. It is taken in a pressed and biased state (=t kJ).

That is, the crushing rollers 5a, 5I are rotatably supported by roller shafts 9a, 9b inserted into the crushing chamber 8 from the main casing 7, and the roller shafts 9B, ! +1. , horizontal shafts 10a and 10I provided outside the main body casing 7.

an arm IL swingably mounted on the vertical inner surface of the
111. When the tip of the bolt 13 screwed onto the stopper arm 12 of the stopper mechanism comes into contact with the arm 11a (1lb), the contact between the crushing rollers 5a, 5b and the annular groove 3 is gap between 6
A minimum width limit is set.

Moreover, the above-mentioned set of arms 11a, 111. Each tip of
Rod 153.15I via tensioning device 14.

are connected by.

Therefore, the raw material supplied to the center of the upper surface of the crushing table 1 moves toward the outer circumference, that is, into the annular groove 3, due to the conical upper surface shape of the crushing table 1 and the centrifugal force caused by the rotation of the crushing table 1, and is crushed. The rollers 5a, 5I, and handles are caught in the gap 6 between the crushing table 1 and crushed under pressure.

Therefore, when the rotation speed of the grinding table 1 is constant, the throughput of a roller mill is the sum of the table pitch diameter and the pitch diameter of the annular groove 3.The processing capacity is high, and is generally proportional to the 2.3 to 2.6 power of the table pitch diameter. It is thought that then.

In addition, if the layer thickness of the raw material bitten by one of the crushing rollers, for example 5a, is too thick, the I51 crushing +1-ra 5n will resist the rotating biasing force of the tensioning device 14 and escape in the -L direction. The rotating force is applied to the crushing roller 5 on the other side via the rad 15a, the tension device 14, and the rostro 15.
The force is transmitted to the arm 11L to which the crushing roller 5t is attached, and presses the crushing roller 5t in the direction of the annular groove 3, so that the pressing force of the crushing rollers 5a, 5t is automatically adjusted according to changes in the layer thickness of the raw material. It is composed of

The raw material thus crushed by the crushing rollers 5a and 5b is crushed by the centrifugal force of the crushing table 1)
The particles move to the outer periphery of the grinding table l and are blown up by the upward air flow flowing out from the upward nozzle 16 surrounding the outer periphery of the grinding table l, and are sorted by particle size by a sorting device (not shown) installed at the top of the grinding chamber 8. , only fine powder with a certain accuracy or less is taken out of the crushing chamber 8 and does not reach a certain accuracy.
llt5) is returned to the -E surface of the grinding table 1 again and is subjected to the grinding process.

Grinding rollers 5a, 5 in a conventional roller mill
The radius of curvature when cut along a plane passing through the outer circumferential surface 4 of I, and the roller shaft 9a or 9 of the annular groove 3 of the crushing table 1, and R is conventionally R>r.

In the example shown in Figure 2(a) R=R1Xr=r1. R1=r, +a.

d,=d.

The thickness d in the radial direction of the crushing roller in the gap 6 between both convex surfaces is
is constant (d,), and in the example shown in Figure (b), R=R1, r-R2, R1>r, +a.

The case where R1>R2+d2, d2>d6 is shown, and the thickness d of the gap 6 between both convex surfaces is the thickness d of the central part. The thickness d2 on the front end side or the rear end side is set to be significantly larger than that on the front end side or the rear end side.

Therefore, in the conventional roller mill, as shown in FIG.
and the annular groove 3. Therefore, during the pinching, a pressing force FI acts on the raw material G in a direction perpendicular to the roller shaft 9 that supports the crushing roller 5, and this pressing force F
A shearing force F2 in a direction perpendicular to + acts, and the raw material pulverized by the shearing force F2 tends to flow out from the gap 6 in the direction of the axis of the roller shaft 9 (that is, forward or backward).

In a roller mill, the layer thickness of the raw material G, that is, the thickness of the gap 6, changes rapidly due to the forward or backward outflow of the raw material.
Since the crushing roller 5 does not rotate unevenly, the crushing roller 5 vibrates. The self-excited vibrations occur each time a new raw material is bitten and pulverized, and the more the raw material is pulverized, the more That is, the smaller the coefficient of friction of the raw material powder is and the greater the tendency of the raw material powder to flow in the axial direction of the roller shaft 9, the more likely it is to occur, and in extreme cases, it will become impossible to operate.

In the case of a roller mill, as shown in FIG. 3 when the crushing roller 5 is viewed from the front, the raw material is crushed not at a point 16 directly below the roller where compression has been completed, but at a biting point at the rear of the crushing table 1 in the direction of movement. 17 (a point l behind the center of the roller), and as shown in FIG. direction) peripheral speed F3
, the circumferential speed F of the outer circumferential surface of the crushing roller 5 in the rotational direction.

is deviated by an angle α, and a shearing force in the direction R5 acts on the raw material directly below the biting point 17 corresponding to this deviation angle α, and this shearing force F5 also prevents the flow of the raw material powder. This is thought to increase the automatic swing J.

In this way, the reason for the automatic vibration of Grinding 1 Nora 5 is that the gap is 1:1.
This is due to the flow of the raw material powder in the direction of the roller axis 9 at 1G, but as shown in Figs. 1 and 2, in conventional roller mills, the thickness of the gap 6 is constant in the direction of the axis 9. (Figure 2 (a)) or 11;i than the central part
The thickness of the end or rear end is greater (Figure 2 (b))
In any case, since it is open to the front and rear, the shape is not designed to block the flow of raw material generated in the gap 6, and the structure is likely to cause self-excited vibration. -ing

In addition, in the conventional roller mill, as described above, the grinding material is structured so that it easily flows out (escapes) from the gap 6 between the grinding roller 5 and the grinding table 1, so that the pressing force 1 of the grinding roller 5 is reduced. The raw material escapes before it can be effectively applied to the raw material powder, and sufficient compression and crushing is not performed, which is one of the reasons for reducing the throughput of the roller mill.

The present invention is based on experimental results showing that the shape of the gap 6 and the radial position of the grinding table greatly affect the throughput of the roller mill and also affect the amount of vibration. The purpose of this is to provide a method for operating a roller mill that can freely adjust the processing capacity and the degree of vibration. In a method of operating a roller mill that crushes raw materials under pressure between an annular groove and the outer peripheral surface of a crushing roller that is rotatably attached to an oscillating roller shaft, the dry crushing roller is slid on the roller shaft. The present invention provides a method for operating a roller mill, which includes: (1) adjusting the sliding amount of the crushing roller while maintaining the operating state;

Next, with reference to the accompanying drawings from FIG. 5 onwards, an embodiment in which the present invention is embodied will be described to provide an understanding of the present invention. Here, FIG. 5 is a side sectional view of a crushing roller drive device that can be used to carry out the operating method of the present invention, and FIG. 6 is a side view showing a modified example of the crushing roller that can be used in the same drive device. , FIG. 7 is a hydraulic circuit diagram capable of carrying out the operating method according to the embodiment of the present invention, and FIG. Rod 1 that can be used: A side sectional view of the J-took device, No. 9, No. 1 is a graph showing the effects of the present invention.

Note that the same reference numerals are used for components common to those of the conventional example shown in FIG.

In FIG. 5, the arm 11, which is attached to the horizontal shaft 10 so as to be swingable in a vertical plane, has a roller shaft 9 attached thereto, as in FIG. A thrust shaft 20 coaxial with the roller shaft 9 is installed in the hollow part of the roller shaft 20, and a slide sleeve 21 is fixed to the tip of the thrust shaft 20 by a nut 22 screwed onto the thrust shaft 20. .

The slide sleeve 21 has a substantially cylindrical shape, and has a spline 23' on its inner surface that engages with a spline thread 23 carved on the outer periphery of the tip of the roller shaft 9. It is slidably fitted into the portion 24.

2 +11i1 on the outer periphery of the slide sleeve 21
The inner races of the bearings 25a, 25s are fixed, and the inner races of the bearings 25. and 25I are fixed to the inner circumferential surface of a cylindrical roller housing 26 coaxially fitted to the crushing roller 5, and these bearings 2
58 and 25I, the reeler housing 26 and the crushing roller 5 integrated therewith are configured to be rotatable with respect to the roller shaft 9.

A cover 27 that covers the front end of the slide sleeve 21 is fixed to the front end of the roller housing 26 . Further, a cover 30 is fixed to the rear end of the roller housing 26 via a sealing member 28, and is in sliding contact with the large diameter portion 29 of the roller shaft 9. The intrusion of dust, etc. is prevented.

The thrust shaft 20 is mounted in the hollow part of the roller shaft 9 through bearings 31a and 31b so as to be slidable in the axial direction, and the rear end thereof is connected to the tip of the cylinder rod 33 through a coupling 32. The part is attached. The cylinder rod 33 axially passes through a substantially cylindrical casing 34 attached to the rear end of the roller shaft 9 and a rod lock device 35 attached to the rear end of the casing 34, and furthermore, the cylinder rod 33 passes through the rod lock device 35 attached to the rear end of the casing 34. It is engaged with a piston 37 of a hydraulic cylinder 36 fixed to the front end of the locking device 35.

1 - One end of the actuating rod 38 attached to the force distribution Sopring 32 is connected to the detection rod 40 of a potentiometer 39 fixed to the rhenodrome locking device 35 marked -1, and the potentiometer 39 is integrally connected to the coupling 32. The thrust shaft 20. moves in the axial direction of the roller shaft 9. Slide sleeve 21. The movement amount S of the bearing 25B+25b roller housing 26 and the crushing roller 5 is detected, converted into an electric signal and sent to the control device, and an indicator (support needle) is activated to allow the operator to visually confirm the current position of the crushing roller 5. It can be so.

Also, two hydraulic pipes 41 connected to the hydraulic cylinder 36. and 411. is the arrow of piston 37 Ell 42
．． or 42I, for supplying pressure oil to the hydraulic cylinder 36 for outward or inward movement.

As shown in FIG. 8(a), the structure of the rod lock device 35 is such that the cylinder rod 33 is tightly fitted into a substantially cylindrical sleeve 42 made of an elastic member whose position is fixed. The oil passages 43+1 and 43b for supplying pressure oil between the sleeve 42 and the cylinder rod 32 are fitted in the casing 35. to which the sleeve 42 is attached. and 35.

Therefore, oil passage 43+! and 43I, when pressure oil is not supplied inside the sleeve 42, the pressure inside the sleeve 42 is low, so the sleeve 42 contracts due to its own elastic force and tightens the cylinder rod 33, so that the cylinder rod 33 cannot move in the axial direction. do not have.

On the other hand, oil passage 43. When pressure oil is supplied from the cylinder rod 43 and the cylinder rod 43, this pressure oil is supplied between the sleeve 42 and the cylinder rod 33, and the sleeve 42 is expanded as shown in FIG. 8(b). The NJ force is eliminated, and the cylinder rod 33 can move freely in its axial direction.

The cross-sectional shape of the outer peripheral surface 4 of the crushing roller 5 shown in FIG.
Although the crushing roller has a generally arcuate shape, the shape of the crushing roller that can be used in the present invention is not limited to such an arcuate shape.As shown in FIG. ．． The entire outer circumferential surface of the crushing roller 5 may be formed into a substantially right cylinder shape, a substantially truncated cone shape, or a substantially drum shape that is depressed in the direction of the roller shaft 9. As described later, such a roller shaft 9
By forming an annular groove 48 that is concave in the direction of , or by forming the entire crushing roller into a drum shape, the crushed raw material is prevented from flowing out in the radial direction of the crushing table, and the vibration of the crushing roller is reduced.

Next, referring to FIG. 7, a hydraulic circuit used for controlling the roller drive device shown in FIG. 5 will be described. Hydraulic pipes 41 a and 411 connected to the hydraulic cylinder 36
．． is connected to a double solenoid type 4-boat valve 45 via an external pilot-type counterbalance valve 44 and a pair of control valves 45a and 45I with check valves, and this 4-port valve 45 is connected to a hydraulic pump P. There is. Also, the oil passage 43 of the Rondo lock device. and 431.
The hydraulic piping 46 connected to the
It is connected to the hydraulic pump P via a boat valve 47.

Next, the operation of the above embodiment is further increased by 8F<8Q.
I will clarify.

Now, to explain the case where the 3-boat switching valve 47 and the 4-port switching valve 45 are at the positions shown in FIG. 7, in this case, all the pressure oil from the hydraulic pump P is released to the tank, so the Piping 41R and 411. Pressure oil is not supplied to any of them, and no force is applied to push the piston 37.

Therefore, the cylinder rod 33 is connected to the ζ piston 37. Thrust shaft 20. Slide sleeve 21. Bearing 258.251.
and the crushing roller 5 attached via the roller housing 26 as shown in the arrow 42 . Or 42I.

Since no force is acting to move the sleeve 42 outward or inward (not shown), and no hydraulic pressure is acting on the inside of the sleeve 42 through the oil passages 43a and 43t, the sleeve 42 is in the eighth position. As shown in Figure (a), the cylinder rod 33 is compressed and the cylinder rod 33 is tightened.
cannot move in the axial direction, and the position of the crusher 1-1-ra 5 relative to the crusher table 1 is fixed.

In such a state, for example, if it is necessary to increase the throughput or dampen vibrations, first operate the solenoid of the three-boat switching valve 47 to connect the hydraulic power source and the hydraulic piping 46.・L, Pressure oil is sent between the sleeve 42 and cylinder blonde 330 via the hydraulic piping 46 and oil passages 43a and 43b to remove the sleeve 42 as shown in FIG. 8(b).
The cylinder rod 33 is expanded as shown in FIG. 2, and by releasing the tightening force, the cylinder rod 33 can be moved in the axial direction.

When the four-boat switching valve 45 is switched, for example, to the right as shown in FIG.
．． through the side check valve to reach the counterbalance valve 44;
Hydraulic piping 41. Balance valve 44 on the side connected to. is supplied to the hydraulic cylinder 36 through the piston 37 as shown in the arrow 4.
2. At the same time as pushing outward as shown by
The balance valve 44I connected to the hydraulic piping 411.1 is supplied to the side pyro port 411. The oil discharged through the balance valve 44I and the check valve on the side reaches the speed control valve 45.
The water passes through the throttle valve of the speed control valve 451°, reaches the four-boat switching valve 45, and is discharged into the tank.

By switching the four-boat switching valve 45 to the right in this manner, the piston 37 and the crushing roller 5 that moves together with the piston 37 are moved to the arrow 42. When the crushing table 1 is moved outward in the radial direction as indicated by , and the piston 37 is moved by the stroke indicated by S, the crushing roller 5 is also moved outward by the same distance to the position indicated by the two-dot chain line 5'. . Due to this outward movement of the grinding roller 5, the position of the raw material clamping portion between the grinding table 1 and the grinding roller 5 moves outward, and as the table pinch diameter increases, the processing capacity of the roller mill increases. Therefore, it is possible to increase the amount of raw materials supplied while keeping the particle size of the product constant. Furthermore, as a result of moving the crushing roller 5 outward as described above, the shape of the gap 6 between the outer peripheral surface 4 of the crushing roller 5 and the annular/l1lS3 of the crushing table l changes, and The cross-sectional area of the gap 6 decreases as the direction increases, forming a so-called wedge-shaped gap, and the raw material that has entered this wedge-shaped gap is prevented from flowing outward, so that the raw material does not slide outward and the crushing roller 5's self-excited vibration is reduced.

Further, when the four-boat switching valve 45 shown in FIG. 7 is switched to the left with the Rondo lock device 35 open as described above, the pressure oil is transferred to the speed control valve 45I, the balance valve 441. The crushing roller 5 flows into the hydraulic cylinder 36 through the hydraulic pipe 4th, urges the piston 37 inward (not indicated by the arrow 42), and moves integrally with the piston 37, as shown by the solid line in FIG. 15) The gap 6 between the outer peripheral surface 4 of the crushing roller 5 and the annular groove 3 is opened outward, and the crushing roller 5 and the crushing table 1 are crushed. If the location moves inward in the radial direction of the grinding table 1 and the table pitch diameter becomes smaller, the same result will occur, resulting in a decrease in processing capacity, and the thickness of the gap 6 between the grinding roller 5 and the grinding table 1 must be reduced to a certain level. It is possible to reduce the raw material supply amount while maintaining the same amount, and it is possible to respond to fluctuations in processing capacity in the front or back steps.

r Experimental Example j The crushing table was driven at 8 ORPM, the pressing force per crushing roller was 1.5 t, and the amount of air blown into the mill chamber from the nozzle 16 was 1 oIrr/min. The processing capacity (Table 1) when the center position iF+: is provided on the center line of the curvature radius of the annular groove like a conventional roller mill, and the processing capacity when the center position iF+: is set on the center line of the curvature radius of the annular groove as in a conventional roller mill. Tables 1 and 2 show the processing capacity (Table 2) when installed in

In these tables, the number in the F column is the processing capacity (kg/h)
The left side of the middle number is the Blaine value (c
+a/g), and the number on the right side indicates the pulverization efficiency (c+il/kwh), and the bottom row indicates the stability of the operating condition, which corresponds to the rotation speed of the sorting device. ing.

As is clear from Tables 1 and 2, by displacing the position of the crushing rollers in the outward direction of the crushing table as in the method of the present invention, it has become possible to significantly increase the throughput.

Also, to explain these experimental results using Figure 9, which shows the relationship between processing and Blaine values, ○ and △ in 1) are the experimental values when the crushing roller is placed in the conventional position, ・, ◎ are the Experimental values are shown when the grinder is eccentrically outward from the table pinch radius when the grinder is pulverized in the direction of the present invention. In addition, △ and ・ are when the four annular parts 4□ are provided on the outer peripheral surface of the crushing roller as shown in Figure J, and ○ and ◎ are when a crushing roller with an arcuate cross section as shown in Figure 5 is used. be. As is clear from the figure, it is understood that when the particle size of the product is constant, the throughput can be changed significantly by changing the position of the crushing rollers in and out.

As described above, the present invention includes an annular groove having a substantially arcuate cross section provided on the top surface of a crushing table that rotates around a vertical axis;
In a method of operating a roller mill in which raw materials are crushed under pressure between the outer peripheral surface of a crushing roller rotatably attached to a roller shaft that moves in an oscillating manner, the crushing roller is slidably attached to the roller shaft. This method of operating a roller mill is characterized by adjusting the sliding amount of the grinding rollers while maintaining the operating state, so the roller mill continues to operate its own throughput in accordance with changes in throughput in the processes before and after the roller mill. It is now possible to change the state as desired, enabling efficient operation of the entire processing process, and suppressing vibrations that occur during operation due to wear of the grinding rollers or grinding table, etc. We have succeeded in providing an extremely practical roller mill that allows us to find the optimal conditions without reducing the operating rate.

[Brief explanation of drawings]

Figure 1 is a side sectional view of a conventional roller mill, Figure 2 (a),
(b) is a side cross-section showing the relationship between the shapes of the crushing roller and the crushing table of the same roller mill, Figure 3 is a) iF side view of the crushing roller to explain the crushing state, and Figure 4 is is a plan view of the same crushing roller, FIG. 5 is a side sectional view of a crushing roller drive device that can be used to carry out the operating method of the present invention, and FIG. 6 is a side sectional view of a crushing roller that can be used in the same drive device. FIG. 7 is a side view showing a modified example, and FIG.
Figures (a) and (b) are side sectional views of a mouth/throat L1 lock device that can be used in the drive device for the crushing roller shown in Figure 5, and Figure 9 is a graph showing the effects of the present invention. . (Explanation of symbols) 1... Grinding table 2... Vertical axis 3... Annular groove 4... Outer circumferential surface 5... Grinding table 6... Gap 9... Roller shaft 20... - Thrust shaft 21... Thrust sleeve 23... Spline joint 35... Rod rotator device 36... Hydraulic cylinder 37... Piston 39... Potentiometer. Applicant Kobe Steel Co., Ltd. Onoda Cement Co., Ltd. Representative Patent Attorney Takeo Honjo Figure 2 (a) Figure 4\ /

Claims (1)

[Claims] The raw material is squeezed between an annular groove with an approximately arc-shaped cross section provided on the top surface of the grinding table that rotates around a vertical axis, and the outer peripheral surface of the grinding roller that is rotatably attached to a swinging roller shaft. A method of operating a roller mill for grinding, characterized in that the grinding roller is slidably attached to the roller shaft, and the amount of sliding of the grinding roller is adjusted while maintaining the operating state.