SU1509470A1 - Method and apparatus for automatic control of process of milling composite masses of semifinished products in production of sheet materials - Google Patents

Abstract

The invention relates to the paper industry, in particular to the automatic control of the processes of preparing fibrous suspensions of complex composition and grinding of fibers. The purpose of the invention is to increase the efficiency of control of the grinding process of the composite mass of semi-finished products. The first and second grinding units for adjusting the grinding degree value, the speed sensor, the first and second differentiation units, the unit for setting the flow rates of component masses, the calculation unit for determining the concentration with the switching unit, the first and second comparison units and the second and third adders are added to the automatic grinding process control unit. . In the process, the value of the degree of grinding, the ratio of the current value of the concentration of the semi-finished product and the two measured values of the degree of grinding are additionally determined. The power and speed of the drive are measured, the ratio of the current values of the concentration of the semi-finished power and the drive speed is determined. Then, the ratio of the costs of the component masses of the semi-finished product to the volumes of the pulper is determined. The value of the ratio of the current values of the fiber breaking length of the magnitude of the power and speed of the drive is determined, and the adjustment value of the grinding degree regulator is additionally adjusted. The adjustment of the flow rates of the component masses is made in proportion to the values of the fixed value of the concentration and the breaking length until the previous and subsequent values of the breaking length and the drive speed are equal. 2 sec. f-ly, 1 ill.

Description

The invention relates to the paper industry, in particular to the automatic control of the processes of preparing fibrous suspensions of complex composition, the grinding of fibers,

The purpose of the invention is to increase the ca-. grinding properties of the composite mass of semi-finished products.

The drawing shows the scheme of automatic control of the process of grinding the composite masses of semi-finished products in the production of sheet materials,

The device contains a grinding apparatus. 1, rotor additive device 2 and drive 3 of the grinding apparatus 31509

rata, a pulper equipped with a conveyor 5 for supplying dry semi-finished products, scrap and podzchi water lines, slurry slurries into a bath of hydro- sizing and grinding with sensors 6 (t) and 7 () mass temperature, first adder 8, meter 9 of drive power, the first computing unit 10 for adjusting the grinding degree value, the first relay 11, the grinding degree controller 12 with the setting device, the second relay 13, the first differentiation unit 14, the sensor 15 for the drive speed, the unit 1b for determining the current value of the concentration of fibrous semi-finished products, the second adder 17 , blocks 18 and 19 comparisons, blocks forming the current value of the degree of grinding by the temperature difference 20 and the drive power 21. Switching unit, made of valve 22 and repeater 23 block 2k calculating the driving concentration, flow setting unit 25., component masses, flow controller liquid reject consists of a controller 26, an automatic reject supply valve 27 and a water supply valve 28, a switching signal generating unit 29, a third relay 30, a second differentiation unit 31, a third adder 32, a second correction computing unit 23 Ichin freeness.

The method implements the following operations: determining the value of the degree of grinding in the channel of the temperature difference between the semi-finished product after the pulper and after the grinding apparatus and the power channel; the ratio of the current value of the concentration of the semi-finished product to the two values of the degree of grinding, which are determined by the two specified channels, is determined; drive speeds are measured; drive power is measured; determines the value of the ratio of the current values of the concentration of the semi-finished product, power and drive speed; in proportion to this value of the ratio, the first correction is made to the value of the setting of the grinding degree regulator, which changes the value of the rotor additive; the value of the ratio of the flow of component masses to the pulper and the current value of the concentration of the briquette hemlock, the volume of the pulper, its filling and the content of the scrap in it is determined; in proportion to this value the ratios are regulated

costs of water, wet rejects, dry rejects and pulp in a pulper measure; rets rupture length; The value of the ratio of the current values of breaking length, power and drive speed is determined.

The device works as follows.

The signals from sensors 6 and 7 of the semi-finished product temperature after the pulper and after grinding go to the first adder 8, where the temperature difference T T - T ,, is determined functionally related to the current value of the degree of grinding SR. The signal from the sensor 9 of the current value of the power consumed by the drive 3 of the grinding apparatus 1, also functionally related to the degree of grinding, goes to the first computing unit 10, in which the value of the first correction SR SR C, C + 1 J the degree of grinding on each current is determined step n + 1 adjust the additive rotor. The signal for this task correction is generated by implementing in block 10 the equation

° 3; Gp-i MiWJ / n +

dWdv dt

pz MsQvp

- And and,

(one)

1, р, f / 3 complex proportionality coefficients, respectively, ° SR kW-; ° 5K-kW-s;

 SR-%

 SR

min about

  amount of power;

 - concentration of the aqueous suspension;

 the number of revolutions of the drive.

If the previously established ratio of the flow of component masses to the pulper is preserved in the technological system and only fluctuating disturbances exist, i.e. there is no signal for correcting the degree of grinding in the electric drive speed channel, and changes in the concentration of the semi-finished product have a small amplitude within the limits of feasibility due to estimates of changes in the rotor additive, then the signal SRcDn + 1 correction task SR

grinding degree through the first relay 11 enters the grinding degree controller 12 (of type PR, 3.21 or RP), in which a signal is generated for the magnitude of the change in the rotor additive, which is changed by means of the additive device 2.

In this situation, the signal of the current value of the revolutions of the drive 3 is blocked by the second relay 1-3, the opening signal for which is the signal of the presence of the value produced d p

one ; perdt molded

BOM differentiation unit 14 (type PF.1) according to the current speed of the electric drive from sensor 15. The value of the current concentration of the semi-finished fibrous semi-finished product required for calculation in block 10 is determined in the first functional block 1b according to

  K, L, expUKj / .O, (2) where K, is a constant coefficient,

 SR

one

n constant coefficient and exponent of piecewise approximation, dimensionless.

Signal of the current value of the difference

 WuT- wdv

 ° SR grinding

. deviation

the values of the degree of grinding of the fiber semi-finished product, determined by the channels of the temperature difference dT of the ground semi-finished product and the drive power Wfjv, are formed in the second adder 17. The values of

current degree deviations

SR

SR

According to the data from the given value, the d-t kanoMoJia are determined in the corresponding first 18 and second 19 comparison blocks. Cu | - The values of the current values of the degree of grinding in the channels of the temperature difference and the drive power are formed in the corresponding second 20 and third 21 function blocks of the same type.

(3) (4)

where ii, the complex proportionality coefficients are consistent9 70

ten

15

The signal value of the current value of the concentration Q p of the fiber semi-finished product from the block 16 also flows through the valve 22 and the repeater 23 to the second computing device. In this situation, the valve 22 is open and the signal of the current value Q Cn + lJ is repeated in block 23, and also repeated in block 2k of the reference concentration calculation and then used in block 25 of the task to generate signals of the three component flow rates to the hydraulic distributor 4. The magnitude of the task for the consumption of scrap in the pulper is determined by the equation

 K ,, v: p.G; (Q; tn + iib (5)

vp

G: where is the volume of the filler of the hydraulic breaker of the suspension of the fibrous semi-finished product, the normalized content of the recycled fiber in the volume of all the fiber supplied to the pulper,%.

0.312; p 1.05 is a constant coefficient and an indicator of the degree of approximation of the dependence of the concentrations of the working semi-finished product, respectively, (h%), dimensionless.

The magnitude of the task for water flow into the pulper is calculated by the equation

TO.

V, VK, A, - vp

 17 n

/ Qi; in-blf - A,).

(6)

where is l, l

100; 3.212 -10-3

constant values, respectively,%, dimensionless;

0

five

K, Kg

0.01; 320.5

- constant coefficients, respectively,

(-H) -, -M-3;

 1.05 is an exponent, dimensionless.

The value of the pulp and dry reject specification is calculated by the equation

g

It is valid SR-kW.

 SR-T- cF :: n + 1 K, V, (. 11

- Gt), (7)

where K 0.01 is a constant coefficient, (| .h) -. The signals for setting the flow rates of the component masses are fed to the ratio controller 26, which changes the degree of opening of the corresponding automatic valves on the scrap supply lines 27 and water 28, and also changes the pulp and dry scrap to the pulper.

During fluctuating disturbances in the fiber development system, the ratio of LT and W changes which are converted in blocks 20 and 21 to the value of the current value of the degree of grinding according to these measurement channels, ° SR / f, SR4, and then in blocks 18 and 19, respectively, The deviations of the current values of the degree of grinding 4 SR jt and 4 ° SR from the specified value °. In adder 17, their difference is determined, and in functional block 1b, the current value of the concentration of the fibrous semi-finished product, which is used in block 10 to form a grinding degree setting correction signal according to equation (6) and is adjusted by changing the degree of rotor addition in this operating mode system.

If, after regular adjustment of the rotor additive, a significant increase in the drive power is observed, it is not adequate to the rotor additive value, then there are favorable conditions in the system for increasing the productivity of the grinding apparatus. The presence of these conditions is monitored using a switch signal generation unit 29, where the values of the current concentration banner and its target value are compared, and established empirically and correspond to the maximum amplitude of the fluctuating disturbances. in this grinding system. With intensive growth of the degree of grinding i. Qvpfn 7 / O VP in block 29 a signal 1 is generated. which opens the third relay 30 and switches the first relay 11. This turns off the grinding degree control circuit for the channel for the ratio of the temperature difference and drive power, and turns on the adjustment channel for the length of the breaking length determined by the result of regular analysis on the breaking machine with TAPPI conditions (STANLART). To calculate the correction value of the setting of the degree of grinding over a breaking length channel, use the equation

ten

 8k7, Cn + 1 n +

U, dR. dt

 P4

(eight)

where y, f / - constant) 1nnye coefficients

 ; SR (rpm

respectively

about from /. . / -t

 SR (m / min)

0

five

0

Through the open relay 30 from the setpoint, the signal of the current value of the breaking length enters the third summeter 32, where the difference with the nominal value for the given type of product Rf is determined. The result of the comparison pesteps into the computing unit 33 for the correction of the magnitude of the degree. In the second differentiation block 31, the current value of the derivative is determined, the signal of which is supplied

in block 33, one of the inputs of which is also connected to the relay 13 of the channel measuring the current value of the drive speed. In block 33, by implementing equation 8),

the correction signal, which, via the switched channel of the relay 11, enters the controller of the 12 degree of grinding. Moreover, in the drive overload mode, leading to a change in its revolutions, which is recorded in the differentiation unit H, the signal of the latter opens the relay 13, through which the signal of the current value of the actuator speed enters the block 33. By this signal, the calculated value of the grinding degree correction correction decreases and thereby relieves the rotor of the apparatus until the drive becomes equal to the nominal, i.e. n - const.

To calculate the corrected value of the concentration of the milled fiber semi-finished product, use the equation

55

   + +

H.-g

(9)

where f, constant coefficients, respectively,%.,% (m / min).

in the channel switching mode, signal 1 from block 29 enters valve 22, closes it and thereby fixes the last concentration value in repeater 23, the signal of this magnitude enters computational block 24 where equation (8) is realized. The current values of LKc values and in block 24 come from the corresponding blocks 31 and 32. The value of the driving concentration calculated in block 24 enters the block 25, where, by implementing the equations, new, in this step, adjustment and in this situation a sharp increase in concentration are determined tasks, the component mass flow rates into the pulper, which enter regulator 2b, until the previous and subsequent values of breaking length are equal to each other.

Claims (2)

1. A method for automatically controlling the grinding process of composite masses of semi-finished products in the production of sheet materials, including measuring the temperature difference between the ground flow of the composite mass after the pulper and the grinding apparatus, determining the power consumption of the grinding apparatus and controlling the amount of setting the grinding degree controller and the consumption of component masses in the hydro- to the splitter, with the fact that, in order to improve the quality of grinding the composite masses, The value of the degree of grinding, depending on the temperature difference between the grinding flow of the composite mass after the pulper and the grinding apparatus and the value of the degree of grinding depending on the power of the grinding apparatus, determine the ratio of the current value of the concentration of the semi-finished product to the two measured values of the degree of grinding, power and speed of the drive, determine the ratio of the current values of the concentration of the semi-finished product, power and 0 0 five drive and depending on the deviation of the measured value from the set, adjust the setting value of the grinding degree regulator, then determine the ratio of the flow rates of the component masses to the pulper and the current value of the semifinished concentrate, the volume of the pulper, its filling with the suspension of the fibrous semi-finished product and the content of reject fiber and depending on the deviation of this value from the target, the flow of the component masses into the pulper is controlled, the value of the ratio of the current x magnitudes of discontinuous lengths of fibers, the amount of power and drive speed proportional to this quantity and further corrected value specifying regulator freeness, and adjustment of component mass flow m is produced proportional to the concentration of a fixed value and breaking length 0 five 0 five 0 five until the previous and subsequent values of breaking length and revolutions of the drive become equal. 2. A device for automatic control of the grinding process of composite masses of semifinished products in the production of sheet materials, containing mass temperature sensors placed in pipelines of the pulper and connected to the first adder, a grinding drive power meter with a grinding unit regulator connected to a rotor additive device a liquid discharge regulator connected to automatic valves on the supply line to the pulper is distinguished by the fact that Improving the efficiency of controlling the grinding process of a fiber semi-finished product, the first and second blocks of correction of the degree of Yomol, the first and second differentiation units, the unit for setting the flow rates of the component masses, the calculating unit for determining the concentration with the switching unit, the first and second units of comparison, the second and the third adders, the second adder being input and connected to the comparison units, the first input of the first comparison unit is connected to the first input of the second comparison unit and to - the setpoint of the degree of grinding, the unit for forming the values of the current values of the degree of grinding by the temperature difference is connected between the output of the first adder, the input of the setpoint generator and the second input of the first comparison unit, and also three relays are introduced, the first relay is connected to the setpoint master, the third relay, to the output of the first milling degree correction unit, and to the milling degree regulator input, the second input of the first relay is connected to the output of the second milling level correction unit, the first one the stroke of the first grinding unit magnitude correction unit is connected to a drive power meter, the second to fifth inputs are connected to constant value setters, the sixth input is connected to the second relay and the first input of the second grinding level correction block, the second to fourth inputs are connected to setpoint controllers these values, the fifth input is connected to the first input of the third adder, and the sixth input through the second differentiation unit to the third relay and to the second input of the third adder, the third input of which is connected with ikami breaking length, a drive speed sensor connected to the first input and through the first differential unit .rovani to the second input of the second relay component expenses unit about five masses are connected to sets of constant coefficients, grinding degree,. the filling capacity of the pulper and the recycling fiber content, to the liquid discharge flow controller and to the output of the calculating unit for determining the concentration, the first and second inputs of which are connected to the set factors of the constant coefficients, the third input to the first input of the third adder. the fourth input - to the sixth input of the second unit for adjusting the degree of grinding; also, a block for determining the current value of the concentration of fibrous semi-finished products, a unit for generating the current value of the degree of grinding by drive power, a switching signal generating unit, the first input of which is connected to the concentrator, the second input are connected with the first output of the switching unit, the second output of which is connected to the seventh input of the first correction unit of the value of the degree of grinding, to the third input of the forming unit The switching signal and the output of the block for determining the current value of the concentration of fibrous semi-finished products, the input of which is connected to the output of the second adder, the unit for generating the current value of the grinding power by drive power is connected between the second input of the second Comparison unit and the output of the drive power meter. 5rac, cellulose. J 3 , ri kg int