SU1378919A1 - Automatic control system for grinding in ball mill - Google Patents

Abstract

The invention relates to the field of automatic control of the process of grinding materials in multi-chamber tube mills. It can be used in the building materials industry, heat and power, chemical, mining and other industries. Allows you to improve the quality of management. Contains mill 1, sensor 2 degrees of loading of the mill crushing zone, first amplifier 3, controller 4 loads, unit 5, metering device 6, sensor 7 degree of loading of the mill abrasion zone, second amplifier 8, unit 9, correction regulator 10, divider 11 and adder 12. 1 Il. SL

Description

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Finish product

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The invention relates to the automatic control of the grinding processes of materials in multi-chamber pipe mills, such as cement mixture or raw mix in cement production, and can be used in industrial glazing of building materials, heat and power, chemical, mining and other industries.

The aim of the invention is to improve the quality of control.

The essence of the invention is as follows.

When the mill rotates, the grinding bodies strike the mill body and cause its vibration. The spectrum of oscillations is quite wide. The auditory perception of vibration of the mill body is sound.

The largest amplitude of vibrations of the hull in the crushing zone of the crushed material. Originating in one area of the hull, oscillations span the entire hull. Naturally, the amplitude decays as it is remote from the zone of origin of the oscillations of the body. Consequently, in whatever cross section of the mill housing the vibration sensor is installed, it will everywhere record vibrations due to the vibration of the first chamber body, with different degrees of attenuation.

In order to increase the quality of regulation, it is necessary to subtract the signal of interference caused by the vibration of the body in the zone of the first chamber (the grinding zone) from the signal of vibration sensor of the mill housing.

For example, the magnitude of the interference signal present in the signal of a sensor installed in the abrasion zone can be calculated from the expiration

f, Kf ,,

(

fi K where fj is the interference signal of the abrasion zone sensor J

crushing zone sensor signal j

vibration damping factor during propagation from crushing to abrasion zone.

The calculation by expression (1) is carried out in a division unit (divider).

The value of the useful signal of the abrasion zone sensor is calculated in the adder

f, f, -Kf ,,

(2)

where f is the signal of the crushing zone sensor.

The magnitude of the attenuation coefficient K is calculated during the setup process of the control system 1. A mill perturbation is supplied to the mill input, for example, according to the flow rate of one of the components to be ground and the firing parameters that occur in response to this perturbation of the increment of signals from the vibration sensors of the mill housing.

The value of K is found:

TO

& fi l,

(3)

0

five

0

five

0

five

0

five

where if is the increment of the signal value of the abrasion zone sensor, /) f, is the increment of the signal value of the crushing zone sensor.

The drawing shows a block diagram of a control system.

The system of automatic control of the grinding process in a ball mill 1 contains a sensor 2 of the load level of the grinding mill zone, connected through the first amplifier 3 to the input of the controller 4 loads, setpoint 5 connected to the input of the controller 4 boots.

The system also contains a metering device 6 connected by an input to the output of the regulator 4 loads, and an output to its input, a sensor 7 of the degree of loading of the grinding mill with a second amplifier 8, a second setpoint 9, a single output to the input of the correction regulator 10, which the output is connected to the input of the loading controller 4, the divider 11 and the adder 12, which is connected via the divider 11 with the output of the first amplifier 3 and the output of the second amplifier 8, and the output is connected to the input of the correction regulator 10.

The automatic grinding control system works as follows.

In the steady state initial mode, the sum of the input signals of the adjusting regulator 10 is zero, its output signal is also zero. Similarly, the sum of the input signals of the controller 4 loads is zero. The change in its output signal is zero.

When increasing, for example, the size of the material entering the mill.

the degree of filling of the material into the crushing zone will begin to increase. The vibration amplitude of the mill body is reduced. This will be fixed simultaneously by the sensor 8 of the degree of loading of the grinding zone of the mill and the sensor 7 of the degree of loading of the zone of grinding of the mill. A decrease in the output signal of sensor 2 causes a decrease in the output signal of the first amplifier 3.

In response to this, the loading controller 4 will begin to reduce through the actuator 6 the amount of material (consumption) in the mill. The change of material into the mill by the loading regulator A will occur until such time as a new equilibrium state is established - the sum of the input signals of the 4 loading regulator will again be equal to zero.

Consider what happens with the correction regulator 10. The decreased output of the first amplifier 3 will cause the output signal of the divider 11 to decrease. Simultaneously with the decrease in the output signal of sensor 2, the output signal of the sensor 7 will decrease. At the same time, the output signal of the second amplifier 8 will decrease. Simultaneous and equal in magnitude reduction of the negative and positive inputs of the adder 12 determines the invariance of their algebraic sum - the output of the adder 12. Therefore, the input of the corrective regulator 10, soy Inonii with the output of the adder 12, and not izmenits correction controller 10 does not generate a correction signal controller 4 torus loading. In a known automatic control system, such an adjustment is unavoidable, which makes its control inadequate to the effective interference.

For a variety of reasons, there is no unambiguous relationship between the degree of filling of the crushing zone and the abrasion zone. And the very notion of the degree of filling is arbitrary. For this reason, a change in the abrasion zone filling and a related change in the magnitude of the signal from the sensor 7 may occur (and usually occurs). Moreover, this change in the signal from sensor 7 is no longer accompanied by a synchronous change in the signal from sensor 2.

VNII11I Order 923/7

For example, an increase in the filling of the abrasion zone material will reduce the vibration of the housing in the area of the sensor 7. The signal of sensor 7 decreases, the signal from the output of the second amplifier 8 decreases, the signal from the output of adder 12 decreases. The sum of the input signals of the correction regulator 10 will become different from zero and at its output, according to Vits, a control action, under the action of which the controller 4 will additionally reduce, will correct the material feed to the mill.

Filtration from interference of the signal of the abrasion zone load sensor will allow to obtain a signal more correlated with the quality of the product obtained, for example, the grinding fineness. This will improve the accuracy of information on the degree of loading of the mill (abrasion zone), which will ensure a more rational loading, reduce the specific energy consumption for grinding, improve the quality of the product.

Formula of invention

The system of automatic control of the grinding process in a ball mill, which includes a sensor of the degree of loading of the grinding mill grinding zone, is connected through the first amplifier to the first input of the mill loading regulator by the material, the first unit connected Hbrfj to the second input of the loading regulator, a metering device, the input of which is connected to the output of the load controller, the third input of which is connected to the output of the metering device, the sensor of the load of the grinding zone of the mill is connected to the input of the second amplifier, the second unit, connected to the first input of the correction regulator, the code of which is connected to the fourth input of the load regulator, characterized in that, in order to increase the quality of control, it is equipped with a divider

and an adder, the output of the first amplifier being connected through a divider to the first input of the adder, the second input of which is connected to the output of the second amplifier, and the output of the adder

connected to the second input of the corrective controller.

Circulation 582 Subscription

Claims (1)

SUMMARY OF THE INVENTION A system for automatic control of a grinding process in a ball mill, including a sensor for the degree of loading of the mill crushing zone, connected through a first amplifier to the first input of the mill loading controller, a first meter connected to the second input of the loading controller, a metering device whose input is connected to the controller output loading, the third input of which is connected to the output of the dosing device, the sensor of the degree of loading of the abrasion zone of the mill is connected to the input of the second amplifier, the second master connected to the first input of the correction controller, the output of which is connected to the fourth input of the load controller, characterized in that, in order to improve the quality of control, it is equipped with a divider and adder, the output of the first amplifier through a divider connected to the first input of the adder, the second input which is connected to the output of the second amplifier, and the output of the adder is connected to the second input of the correction controller. VNIIIPI Order 923/7 _____________ Circulation 582 Subscription Production polygr. ave, city of Uzhhorod, st. Project, 4