SU1004508A1 - Method of controlling the process of milling high-concentration mass and system for performing same - Google Patents

Description

The invention relates to the production of pulp and paper and can be used to control the grinding process of a high concentration mass. .

There is a known method for controlling the grinding process of a high concentration mass by measuring the mass concentration in the grinding zone, calculating the magnitude of the functional grinding index and depending on the magnitude of the mismatch of the found and Zeid control index of the technological parameter of the grinding process Ci.

The disadvantage of this method is low control accuracy.

A control system for its implementation is also known, comprising a measuring unit and adjusting the mass level of the thickener, the mass level sensor of which is connected to the first input of the mass concentration measuring unit in the grinding zone, the second input of which is connected to the condensed mass concentration measuring unit and the third the input is connected to the mass flow sensor for diluting the measurement unit and controlling the mass flow rate for dilution, a computing unit whose input is connected to the output

a unit for determining the mass concentration in the grinding zone, and its output is connected to the regulator and a low concentration sensor 1 J.

However, this device has low control accuracy.

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

This goal is achieved by

10 that, according to the method of controlling the grinding process of a high concentration mass, by measuring the concentration of the mass in the grinding zone, calculating the value of the functional index

15 grinding, depending on the magnitude of the mismatch found and specified adjustment index of the technological parameter of the grinding process, measure the volume flow to the masses

20 through the grinding apparatus, determine the value of the useful grinding power, calculate the ratio of their ratio, and regulate the useful grinding power and bulk mass consumption depending on the measured and calculated parameters, as well as the control system for performing the method, and adjusting the mass level in ananna thickener,

Claims (2)

The 30 mass level sensor of which is connected to the first input of the block — determining the mass concentration in the grinding zone, the second input of which is connected to the block for determining the concentration of the condensed mass, and its third input is connected to the mass flow sensor for diluting the measuring unit and controlling the mass flow for dilution, the computing unit, the input of which is connected with the output of the mass concentration determining unit in the grinding zone, and its output is connected to the controller, the low concentration sensor, has a unit for detecting useful power, its unit control unit, a control channel selection unit, a mass volume flow adjustment unit, a mass flow sensor in a common supply line, the low concentration sensor connected to a second input of the computing unit, the third input of which is connected to the mass flow sensor in a common line the fourth input is connected to the output of the net power determination unit, while the controller output is connected to the input of the control channel selection block, the first input of which is connected to the useful power adjustment unit, and its second output is connected to ki volume flow rate. The drawing shows a control system diagram that implements a method for controlling the grinding process in a high concentration mass. The control system contains mass flow sensors connected to the first input of the computing unit 2, the second input of which is connected to the condensation mass concentration sensor 3, and the third input to the output of the block 4 determining the mass concentration in the grinding zone. The first input of the block 4 is connected to the output of the block 5 for determining the concentration of the condensed mass, which is associated with the sensor 6 of the rotation speed of the drum 7 of the thickener and the sensor 8 of the drive power associated with its corresponding inputs. The second input of the unit 4 is connected to the input of the regulator 9 of the mass flow of low concentration supplied to the dilution, the output of which is connected to the control valve 10, and the sensor II of the mass flow in the dilution line of the thick mass, and the third input of the block 4 is connected & sensor 12 mass level in the bath 13 thickener and reg ultorom 14 mass level. The fourth input of the computational unit 2 is connected to the unit 15 for determining the usefulness of which input is connected to the sensor 16 of the drive power of the grinding unit 17 The output of unit 2 via the comparator 18 and the driver 19, which is connected to the control channel selection unit 2, the first with block 21 reg. kodki useful capacity of the device 7, and the second input - with the block 22 reolirovki volume flow mass. Block 20 contains two successively connected functional blocks 23 and 24. The mass from the pool of low-concentration 25 aces enters the thickener bath 13 through a pipeline on which sensors 1 and 3 are installed. A part of the low-concentration mass is fed to dilute the high-concentration mass. A sensor 11, a flow controller 9 and a control valve 10 are installed in this line, which maintains a constant flow in the dilution line. The control system operates as follows. The signals from sensors b and 8 in block 5 determine the concentration of the condensed mass C2 according to the formula - where NP is the drive power of the thickener; n is the speed of rotation of the drum; I dL is a constant coefficient. The concentration of mass C in the grinding zone is determined from the found value and the magnitude of the signal from the sensors 11 and 12 in block 4 by the dependence of PURP - Q3 pYP-constant coefficient; -pressure (level) of mass in the thickener bath; Q is the volumetric mass flow rate of the low concentration supplied to the dilution; (Air is determined from experimental data using the least squares method. The obtained values go to computational unit 2, which also receives signals from sensors 1 and 3 and unit 20, in which the value of the power of the device is determined as the difference between the total measured power of the device and the specified unproductive power losses. In block 2, functional I is calculated by the following formula-C2. where NP is the useful power of the apparatus, Q is the volumetric mass flow rate of the high concentration at the output of the apparatus, C is the mass concentration for dilution, comp The autera 18 compares the value of the currently found functionality with the specified value. The mismatch value is converted by the control signal 19 to the control signal. This signal is sent to the two-channel block 20. The first channel of the block 23 implements a one-sided limitation of the control signal b entered in the disk shift control unit 21. When the gap between the discs is reduced, the magnitude of the drive power of the apparatus increases according to a non-linear law. To prevent discs from coming closer to a dangerous gap, at which the switching off will occur. arata, control signal 5 is limited by value (ed. However, due to the wear of the disks, the regulating effect is not enough to maintain the set value of the functional due to the change in the useful power. Therefore, when the regulating action is reached or exceeded (the limit value 5 automatically switches on the second channel, i.e. block 24, which changes volume flow through a high concentration through block 22. In block 24, the following dependences 2 0 are realized if I 6L, I p 2 if 16 dB where (2 is the control signal of the second channel; ju. is the output signal from block 19 (is the control signal of the first channel; 0 is the limiting value of the signal of the first channel. Thus, the accuracy of quality control p is improved by this system High-concentration mass ash powder Formula of the invention 1. Method of controlling the grinding process of a high concentration mass by measuring the concentration of the mass in the grinding zone, calculating the value of the functional grinding index and depending on the mismatch value of the grinding process technological parameter found, which is different By the fact that, in order to increase the control accuracy, the volumetric mass flow through the grinding apparatus is measured, and, calculating a value of the ratio, and adjusted useful refining capacity and volumetric mass flow rate in dependence on the measured and calculated parameters. . 2. A control system for carrying out the method according to Claim 1, comprising: a measurement and control unit for the level of masol in a thickener bath, the mass level sensor of which is connected to the first input of the unit for determining the mass concentration in the grinding zone; the second input is connected to the block for determining the concentration of the condensed mass, and its third input is connected to the mass flow sensor for diluting the measuring unit and controlling the mass flow for dilution, the computing unit whose input is associated with the output of the mass concentration measuring unit in the grinding zone, and its output is connected to a regulator, a low concentration sensor, characterized in that it has a unit for determining the net power, its adjustment unit, a control channel selection unit, a volume mass flow adjustment unit, a mass flow sensor in the common supply line, the low concentration sensor being connected to the second input of the computing unit, the third INPUT of which is connected to the mass flow sensor in the common line, and its fourth input is connected to the output of the useful power determination unit, while the controller output associated with the input of the selection block. the control channel, the first input of which is connected to the unit for adjusting the effective power, and its second output is connected to the unit for adjusting the mass flow rate. Sources of information taken into account in the examination 1. USSR author's certificate 643570, cl. O 21 D 1/02, G 05 D 7/06, 1977.