JPS6287260A - Roller mill automatic operation control device - 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 an automatic operation control device for a roller mill. In other words, in order to maximize the grinding efficiency of the mill while maintaining the vibrations generated during operation of the roller mill within an appropriate allowable range, changes in the amplitude of this vibration and the amount of crushed material retained in the mill are necessary. This is a control device that automatically links the adjustment of the

In a general roller mill, as shown in FIG. 2, raw materials are supplied into the mill by a raw material feeder 2, and the raw materials are fed to rollers 3 that are provided at the lower part of the roller mill body 1 and rotate at high speed. The roller mill body 1 is charged into a space between it and a pull ring 4 fixed to the lower part thereof, and is pulverized.

- The pulverized product is transported to the classification chamber 6 by air sent into the lower part of the mill by the blower 5 and separated into coarse powder and fine powder.The coarse powder stays in the mill and is pulverized again, and the fine powder is discharged. It is discharged from the lower part and collected by a cyclone 8, a bag filter 9, etc.

The operation of a roller mill generally requires (1) the desired amount of retention in the mill (an indicator for operating at an appropriate grinding capacity);
Adjustment of the feed controller (there are many types such as differential pressure signal system corresponding to the amount of retention in the mill), (
2) Adjustment of the rotation speed of the classifier 10 disposed in the classification chamber 6, (3) Adjustment of the amount of air sent by the blower 5 (by adjusting the inlet damper angle, etc.), (4) Set of feed controller. Adjustment of the supply amount of the corresponding raw material feeder and (5) Adjustment of the rotation speed of the mill motor (corresponding to the rotation speed of roller 3) are manually set in advance, and then the electric motors of each device are started to operate in conjunction with each other according to a sequence. I'm taking it.

The present inventor conducted various studies in order to maximize the grinding efficiency of the roller mill by controlling its automatic operation. According to this, (a) As shown in Figure 3, the increase or decrease in Δp between the differential pressure inside the mill (the static pressure difference between the bottom and top of the mill [indicated by Δp]) is the amount of retention in the mill. (corresponding to the increase/decrease) is correlated with the increase/decrease in the production amount of fine powder in the mill. (b) Also, as shown in Figure 4, when the differential pressure inside the mill exceeds the threshold, the vibration of the mill body will occur. to become abnormally large,
(c) The curve shown in Figure 4 mainly changes left and right due to changes in the particle size distribution of the raw material, pulverizability, etc., so even if △p is small, the vibration may become abnormally large, or △p may become abnormally large. As shown in Figure 3, increasing △p will increase the production volume, but as mentioned above, there will also be fluctuations in the occurrence of abnormal vibrations. In conventional operation with manual setting, Δp is 260 mm4q, so it is necessary to operate safely with such a setting. We found that the regulation value for swing width for safe driving is not constant, as it varies depending on the structure etc.

Based on the above-mentioned knowledge, the present inventor has proposed an operation control device that controls the vibration amplitude (width and amplitude) of the mill body within the regulated values and increases the production capacity of the roller mill as much as possible. a retention amount detector that detects the retention amount of the
A feed material controller that compares the output signal from the retention amount detector with a predetermined first reference value and adjusts the amount of material supplied by the material feeder based on the comparison result, and detects the amplitude of vibration of the mill body. and a feedstock controller that sends a signal to change the first reference value such that when the output signal from the vibration detector deviates from a predetermined second reference value, the output signal falls within the second reference value. We have succeeded in inventing an automatic operation control device for a roller mill, which is characterized by having a reference value controller that sends data to the roller mill.

The structure and operation of the present invention will be explained below based on Examples.

FIG. 1 is a block diagram showing an example of an automatic control device of the present invention.

In the figure, 11 is a vibration detection device (vibration detector) attached to the lower side wall of the roller mill main body. As mentioned above, the occurrence of abnormal vibration in a roller mill is greatly affected by the increase or decrease in the differential pressure within the mill, that is, the increase or decrease in the amount of granular material retained.
Even during steady operation, fluctuations may occur due to changes in the properties of raw materials, etc.

Therefore, this vibration detection device 11 constantly measures fluctuations in amplitude, converts this into an electrical signal, and sends it to the reference value controller 12. In the reference value controller 12, the upper and lower limits of the regulation value of the amplitude for normal operation are set in advance as second reference values. In the embodiment of the present inventor, this second reference value is 40μ to 50μ.
This value corresponds to the amplitude of μ. And vibration detection device 1
If the signal sent from 1 exceeds the upper limit of the second reference value mentioned above, the signal SL that reduces the differential pressure within the mill (reduces the amount of granular material retained within the mill) is controlled to the reference value. vessel 12
If the feed rate falls below the lower limit of feed 9, a signal SR that increases the differential pressure in the mill is sent to the feedstock controller 13 to change the differential pressure setting value of the feedstock controller 13. This differential pressure setting value becomes a first reference value that is a reference for adjusting the raw material supply amount.

On the other hand, the differential pressure within the mill (the differential pressure between the upper and lower parts of the mill), which indicates the amount of stagnation of powder and granules in the mill and its fluctuations, is constantly detected by a differential pressure gauge 14 serving as a stagnation amount detector. A signal S, is sent to the feedstock controller 13. and controller 13
Then, depending on the difference between this differential pressure signal SP and the differential pressure set value determined by the differential pressure decrease signal SL or differential pressure increase signal SH from the reference value controller 12, the electric motor 15 of the raw material feeder is Outputs a signal 5r (i7) for increasing or decreasing the supply amount.

As a result, the amount of granular material retained in the mill (and the differential pressure at the same time) is adjusted to increase or decrease, and the swing width of the mill body also falls within the second reference value, resulting in a steady operation state.

In this actual IM row, if the amplitude is 5011 or more, the vibration is so large that normal operation of the roller mill is impossible and there is a risk of damage to the equipment. If it is less than 40μ, the operation is normal and there is no damage to the equipment, but the mill must be operated with a correspondingly small amount of stagnation, resulting in a reduction in the mill's production capacity.

In addition, in this embodiment, a differential pressure measurement method within the mill was adopted as a signal indicating fluctuations in the amount of stagnation of powder and granules within the mill sent to the feedstock controller 13. It is also possible to use a method of sending a signal indicating the amount of granular material staying in the mill based on power consumption (KW) or the like.

Effects of the Invention According to the present invention, the production capacity of the mill can be maximized while maintaining the vibration during operation of the roller mill within a safe tolerance without damaging the equipment. For example, according to the embodiment of the present invention, in the safe operation using the conventional technology, Δp was 260 mmAq, and the production capacity in this case was about 10.4 tons per hour, but with the present invention, the production capacity was self-supporting within the permissible value of the shaking width. With controlled operation, the production capacity is 11.2
This results in an increase in production capacity of approximately 8%.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one mode of implementing the present invention, FIG. 2 is a process diagram of a general roller mill, and FIG. 3 is a diagram showing the relationship between differential pressure inside the mill and production capacity of a roller mill. Fourth
The figure shows the relationship between the differential pressure and the swing width of the mill body. In Fig. 4, a shows the case where limestone of 10 or less is used as the raw material, and b shows the case where 5H or less of limestone is used as the raw material. ■...roller mill body, 2...raw material feeder,
3...Roller, 5...Blower, 6...Classifying room,
8...Cyclone, 11...Vibration detection device, 12.
...Reference value controller, 13...Feed material controller, ]4.
...Differential pressure gauge, 15...Electric motor -1lll + -1 value 旙 inclination and ward a) law 〃l→裟 so Q≦÷(ri) ward ζ

Claims (3)

[Claims] (1) A roller arranged inside the mill body and rotating at high speed, a fixed pull ring arranged outside the roller with an appropriate gap, and a classification chamber arranged above the roller and the pull ring; The raw material fed by the raw material feeder is charged into the gap between the roller and the pull ring and pulverized, and after being further classified in the classification chamber, the fine powder product is transferred to the mill body. An automatic operation control device for a roller mill that discharges from the top includes a retention amount detector that detects the amount of powder and granules retained in the mill body, an output signal from the retention amount detector, and a predetermined first reference value. a feed material controller that compares the amount of raw material supplied by the raw material feeder based on the comparison result; a vibration detector that detects the amplitude of vibration of the mill body; The above-mentioned first
An automatic operation control device comprising: a reference value controller that sends a signal for changing a reference value to a feedstock controller. (2) The automatic operation control device according to claim 1, wherein the retention amount detector is a differential pressure gauge that detects a differential pressure within the mill. (3) The second reference value in the reference value controller is set to a value equal to the output signal value output from the vibration detector when the mill body vibrates with an amplitude of 40μ to 50μ. An automatic operation control device according to claim 1 or 2.