SU923613A1 - Device for automatic control of closed-cycle mill - Google Patents

Description

The invention relates to devices for automatic control of the grinding process in units with recycling and can be used in the building materials industry, chemical, metallurgical and other industries.

There is a method in which a device for extreme performance control of ball mills is described, comprising a noise sensor, calculating units and an actuating mechanism £ 13.

In this device, the direction of change in the flow rate of the source material is determined by the sign of the sum of the average and current value of the acoustic signal of noise and its derivative. This control device allows to stabilize the re.: They work the grinding unit in a certain range of changes in the circulating load, but does not provide

2

output at maximum capacity of the unit.

The closest to the proposed technical entity is a device for automatic control of a closed-loop mill, containing a load controller, a performance sensor, a load sensor, an extreme controller and a regulating body for feeding the source material, with a performance sensor connected to one of the extreme controller inputs, the output of which is connected with one of the inputs of the load controller, the output of which is connected to the regulating body for feeding the source material, and the load sensor is Connected to another input of the load controller G2 ?.

A disadvantage of this device is that the use of high-speed extreme regulators designed to optimize

3 923613 '4

inertial processes using the first and second derivatives of the performance does not provide a steady search for extremum in the case of objects with recycling, and consequently, management efficiency decreases.

The purpose of the invention is to improve the accuracy of control;

This goal is achieved "0 by the fact that a device for automatic control of a closed-loop mill, containing a load controller, a capacity sensor, a load sensor, an extreme controller, and a regulating body for feeding the source material, and a productivity sensor connected to one of the extreme controller inputs, the output of which is 20

Not one of the inputs of the load controller, the output of which is connected to the regulating body for feeding the source material, and the load sensor connected to the other input of the load regulator, is equipped with a flow sensor. source material, differential and multiplying unit, and the source material flow rate and performance sensors are connected to the corresponding inputs of the differential amplifier, the output of which is connected to another input of the extremal regulator through the multiplication unit. ₃₅

The invention is illustrated as follows.

The equation describing a closed-loop mill with a load control is ₄₀

T (1)

where · / ⁷ is the total load ^Ki > 45

₀ n - the value of the task of the load controller; ·

K - transfer coefficient of the load controller;

T is the time constant of the mill; & a, b - form coefficients of the static characteristics of the mill ;; ί - time.

In the process of searching for an extremum, the magnitude g changes in time as follows, ⁵⁵

where K /.

rate of change

tasks.

The direction of the job change determines the signal-relay of the extremal controller.

Expressions for derivatives of the performance of the mill in accordance with equation (1) can be written as ⁰

_ I ^ olt) a-b 7 t "

but? ⁵⁷ —t-Μ ^% _ητ ) [Μ ^ οη _Τ ) -Κ] \ _ —-—- (6-, (g)

where u - the yield of the finished product;

<5 - the amount of loading of the source material;

^ ept - the value of the total load corresponding to the maximum performance of the mill ..

From the above expressions, it follows that the linear combination of the first and second derivative of the mill productivity and the square of the difference in raw material consumption and productivity is zero at the value of the total load corresponding to the maximum productivity of the aggregate. In this case, the sum is positive in the case of an increase in the task when the values of the total load are less than the optimum, or in the case of a decrease in the task when the values of the total load exceed the optimum. Therefore, a negative amount sign indicates a distance from the optimal value of the total load. ·.

This fact is proposed to use for management.

The drawing shows the proposed device.

The source material 1 is fed to the mill 2. The total load 3 is fed to the classifier where it is divided into the finished product 5 and the coarse fraction (grit) 6 returned to the mill in the mill.

The total load is measured by sensor 7. As a total load sensor, a material flow meter can be used in the classifier, an electro-acoustic noise sensor of the mill, a power meter or a drive current of the transporting device,

5,9236

material into the separator, or the sum of the signals of the indicated sensors. The signal from this sensor is fed to the regulator 8 of the mill load, which changes with the help of the regulator 9 the flow rate of the source material 1. ,

The flow rate of the source material is measured by the sensor 10, and the consumption of the finished product by the sensor 11 of the capacity of the vessel. The signals from the outputs of these sensors are fed to the inputs of the differential amplifier 12. An output signal, proportional to the difference between the consumption of the initial material and the consumption of the finished product, is fed to the two inputs of the duplicating unit 13.

The output signal of the sensor 11 is fed to the first input of the extreme 20 regulator 14, the second input of which receives the output signal of the multiplying unit 13, which is proportional to the square of the difference between the costs of the starting material and the finished product. 25 The output of the extreme controller 14 is connected to the second input of the controller.

8 downloads in quality setting.

The operation of the proposed device is as follows. _thirty

The loading regulator 8 changes the material feed to the mill, acting on the regulator 9, is proportional to the signal of the total load sensor 7, decreasing the feed ₃₅ as the total load increases and increases the material feed to the mill when it decreases.

Extreme controller 14 modifies the task controller 8 downloads.

The work of the extreme regulator is as follows.

The signal from performance sensor 11 is twice differentiated and the received signals, proportional to the first and second derivatives of the finished product consumption, are added to the signal proportional to the square of the difference between the consumption of the starting material and the finished product. The direction of change in the task of the load controller is determined by the sign of the amount received.

Suppose that at the time included ⁵⁵ cheniya extreme regulator value of the total load is less optiyalnoy and job change is in the direction of its increase, and the sum of signals previously mentioned decreases, remains positive as long as the total load does not exceed his? Opt. value, after which the sum sign becomes negative. When a negative amount sign appears, the direction of change of the task to the load control is reversed.

At the same time, the sum again becomes positive and remains positive with reduced tasks of the load controller as long as the total load exceeds the optimal value. Further the cycle of work repeats

The proposed device allows to increase the efficiency of extreme control of a closed-cycle mill and can be implemented both on analog equipment and using computer technology.

Claims (1)

Claim A device for automatic control of a closed-loop mill containing a load controller, a capacity sensor, a load sensor, an extremum regulator, and an input material control regulator, and a capacity sensor connected to one of the extreme regulator inputs, the output of which is connected to one of the inputs of the load regulator the stroke of which is connected to the regulator of the supply of the source material, and the load sensor is connected to another input of the load regulator, which is different from In order to improve control accuracy, it is equipped with a flow sensor of the source material, a differential amplifier and a multiplying unit, and the flow sensors of the source material and performance are connected to the corresponding inputs of the differential amplifier, the output of which is connected to another input of the extreme regulator through the multiplication unit.