SU1331562A1 - Apparatus for automatic control of magnetic separation - Google Patents

Description

1331

the quadrant unit, the output of the quadrant is connected to the second input of the sixth multiplication unit and the first input of the second subtraction unit, the output of which is connected to the second input of the first division unit, which is connected to the second input of the second multiplication unit, the output of the third scale unit

one

The invention relates to the field of automatic control of technological enrichment processes and can be used in the processing plants of non-ferrous and ferrous metallurgy.

The purpose of the invention is to improve the quality of the concentrate by eliminating overshoot.

Fig. 1 shows pulp density transients in the feed of magnetic separation along a channel. Change in water flow to the classifier discharge - Change in pulp density in feed separation with a decrease in water flow by 6% of the nominal; Fig 2 is the same, with an increase in water consumption by 6%; Fig. 3 is a functional block diagram of a device for automatic control of a magnetic separation process;

The device contains a pulp density sensor 1, a density setting device 2, a comparison unit 3, an actuator 4, a water consumption valve 5, reference signal adjusters 6-9, integrators 10-12, multiplication blocks 13-19, algebraic addition blocks 20-22 quadr 23 , scale blocks 24-28 blocks 29 and 30 subtraction, blocks 31 and 32 divisions.

The control object is represented by a magnetic separator 33, installed after the classifier 34,

The pulp density sensor 1 is installed in the power supply of the magnetic separator 33, to which the pulp is fed from the discharge of the classifier 34, the pulp density in the discharge of the classifier is controlled by the actuator 4 and the valve 5, which changes the water flow

562

connected to the second input of the second subtraction unit and the input of the fourth scale unit, the output of which is connected to the second input of the seventh multiplication unit, the output of the sixth multiplication unit is connected to the input of the fifth scale unit whose output is connected to the second input of the first subtraction unit.

into the discharge of the classifier 34. The output of the pulp density sensor is connected to the negative input of the comparator unit 3, to the positive input of which the output of the pulp density sensor 2 is connected.

The output of the first setpoint 6 of the reference signal is connected to the first input of the first multiplication unit 13, the output of which is connected to the third (negative) input of the comparison unit 3, t, e, the polarities of the inputs to which the outputs of the blocks 1 and 13 are connected, coincide. The output of the comparison unit 3 is connected to the input of the first integrator 10 and the first input of the second multiplication unit 14, the output of which is connected to the first input of the first addition unit 20, and the output of the unit 20 is connected to the inputs of the actuator 4 and the first input of the second addition unit 21.

The output of block 21 is connected to the input of the second integrator 11, the output of which is connected to the second input of the first multiplication unit 13, the input of the third integrator 12 and the first input of the third multiplication unit 15. The output of unit 15 is connected to the first input of the third addition unit 22, the output of which is connected to the second input of the second addition unit 21, the output of the first integrator 10 is connected to the first input of the fourth multiplication unit 16, the output of which is connected to the second input of the first addition unit 20.

The output of the second setter 7. The reference signals are connected to the input of the first scale unit 24, the output of which is connected to the first input of the first division unit 31 and the input of the second scale unit 25, the output of which is connected to the first input of the second division unit 32. The output of block 32 is connected to the second input of the fourth multiplication unit 16. The output of the third sensor 8 of the reference signal is connected to the input of the third scale unit 26 and to the first input of the fifth multiplication unit 17, the second input of which is connected to the output of the third integrator 12.

The output of the fifth multiplication unit 17 is connected to the second input of the third addition unit 22. The output of the fourth sensor 9 of the reference signal is connected to the second input of the third multiplication unit 15, the input of the quadrant 23, the first input of the seventh multiplication unit 19, the output of which is connected to the first input of the first unit 29 subtracted. The output of block 29 is connected to the second input of the second block 32 dividing.

The output of the quadrant 23 is connected to the second input of the sixth multiplier 18 and the first input of the second subtraction unit 30 25, the input of which is connected to the second input of the first division block 31. The output of block 31 is connected to the second input of the second multiplication unit 14. The output of the third scale unit 26 30 is connected to the second input of the second subtraction unit 30 and the input of the fourth scale unit 27, the output of which is connected to the second input of the seventh

control systems, their low stability and the occurrence of self-oscillations of the entire process.

The real transient characteristic of the object shown in FIG. 1 and 2, should be approximated by the expression

W (p)

TO,

TO,

T, p + 1

mr

(2)

Where

K, T.

2 t. gain factors; constant time; C is the lag time, Bf (2) by expanding exp (- t p) in the Taylor series is reduced to the expression

W (P)

-Tp + k

a, r

+ a,

(3)

1, - dynamic parameters of the process, which follows from the type of transient processes shown in FIG. 1 and 2. The parameters K, K, T, T and TG are determined by the Kupffmüller method by experimentally detected transient response on the object and are shown in Figs. 1 and 2.

When approximating the transfer function by the Kupfmüller method, the real transition characteristic shown in FIG. 1 and 2, is approximated by the sum of two exponents, the second of

block 19 multiply. The output of the sixth block-35 is shifted by the delay time 6. In this case, from FIG. 1 it follows that the time constant T is close to

This multiplier 18 is connected to the input of a fifth scale unit 28, the output of which is connected to the second input of the first subtracting unit 29.

The essence of the invention is as follows.

Usually, in the practice of automating the enrichment processes, the transient in g; the separation when the flow rate of water into the drain of the classifier is modified is approximated by an exponent (dashed line, Fig. 1 and 2), representing the transfer function of the object in the form

W (p) K (Tr +1) exp (-TP), (1)

where K is the gain; T, T - lag and constant

of time.

The use of linear PI and PID controllers is justified for such an approximation of the transient process and the transfer function.

Automation practice showed unsatisfactory quality of synt40

 (lag time with.

Using the decomposition of B in rd Taylor, we get

{f

R

  %

45

, lt -....

Using the first two terms of the expansion and substituting them in (2), we get

K |

50

W (p)

  T, P + 1 (

After conversion

wfP) iK2

 (T, P + 1) (T, P + 1)

K2

+ D) (t; p + t)

   /

one

ТгТ, Р + 7t, + Т) + Т

ISLIz.

55

lilL.

Rb

Tg-T,

)

  t

 t, t,

control systems based on such a law, their low stability and the occurrence of self-oscillations of the entire process.

The real transient characteristic of the object shown in FIG. 1 and 2, should be approximated by the expression

TO,

TO,

T, p + 1

mr

(2)

gain factors; constant time; lag time (2) by decomposing Taylor is reduced to you

-Tp + k

a, r

+ a,

(3)

1, - dynamic parameters of the process, which follows from the type of transient processes shown in FIG. 1 and 2. The parameters K, K, T, T and TG are determined by the Kupffmüller method by experimentally detected transient response on the object and are shown in Figs. 1 and 2.

When approximating the transfer function by the Kupfmüller method, the real transition characteristic shown in FIG. 1 and 2, is approximated by the sum of two exponents, the second of

 shifted by the delay time 6. In this case, from FIG. 1 it follows that the time constant T is close to

 (lag time with.

Using the decomposition of B in rd Taylor, we get

{f

R

  %

, lt -....

Using the first two terms of the expansion and substituting them in (2), we get

K |

W (p)

  T, P + 1 (

After conversion

wfP) iK2

 (T, P + 1) (T, P + 1)

K2

+ D) (t; p + t)

   /

one

ТгТ, Р + 7t, + Т) + Т

ISLIz.

lilL.

Rb

Tg-T,

)

  t

 t, t,

enter notation

T;

Tjt

TO;

,

T-T

eleven

get the form of the transfer function of the object (3),

To increase the stability and quality of a closed control system, it is necessary to synthesize a structure that, if controlled, would compensate for the unstable numerator of the transfer function of an object of the form (3) or (2) and at the same time have a stability equal to the maximum degree of stability of the system

() with linear pi control.

To accomplish this, we introduce in the structure of a closed control system parallel to the object dynamically a filter of the form

Tr

+ a,

(five)

submitting to its input the resultant control from the system, and its output to the input of the unit of comparison of the control system with the PI controller.

In this case, the transfer function of the closed-loop system is

W (P)

TO,

, р2 + а, Р + ККпР + ККп

(6)

where K and K „are the PI controller settings.

To synthesize the optimal control structure of the object (3), it is necessary to choose such settings, parameters Kf, and Kj, so that the stability of the system for the object (W) coincides with the maximum degree of stability for the closed system of the form (6).

The maximum degree of stability Igi is equal to the extreme right root P of the characteristic control of the lock W

system (6), i.e. 1, -P.

We find 1 by differentiating twice the denominator of expression (6) and equating it to zero. Then

  - (7)

 23.

3 3 To ensure that the quality of the control of the object (3) is not worse than the quality of control of the object (4) or of the object (1), we layer all the roots on

but )

1331562

P, whence we determine that the initial parameters K j, and Kp are equal K (Za, - a) (ZK) - (8) 5 Ci (18a, a - 11a) (27kG, (9) and the transfer function of the regulating part of the system equals

R

W, (P)

 127a, -9a 2Pli8a, a.j + nal,

27KR

Thus, the optimal structure of the control system is synthesized and includes elements with transfer functions (5) and (10), which corresponds to the transfer function of the closed system (6), where the parameters are

and are determined

T, K, a,

Initially, for removed experimentally averaged transients of the form shown in FIG. 1 and 2, and

To are determined by expressions (8)

CP and

and (9).

Taking into account the above, the synthesized control system can be written as the following system of equations

0 5

g

five

ra derived values ...

The automatic control device implements the developed optimal structure and operates as follows.

The blocks interact as follows.

The pulp density is p

t

-; pulp density sensor 1 in pim

The magnetic separator 33. The measured pulp density signal is converted into an analog signal of the electrical voltage U ,.

The setting unit 2 is given a constant voltage, U, proportional to the specified density value

pulp in nutrition p jg.

The setting unit 7 is given a constant voltage and is proportional to the gain of the object K. They amplify the signal from block 7 three times in the scale unit 2A, i.e. at the exit

t

hell

13 of the block 24, a signal U is formed in proportion to the magnitude of the RC,

Similarly to block 24, block 25 produces a voltage signal Ujc proportional to 27K by amplifying the signal U nine times.

The setting unit 8 is given a constant voltage Ug proportional to the dynamic parameter a ,. The Ug signal from block 8 is amplified three times in scale unit 26, i.e. at its output, a signal U is formed proportional to the value of Pro ,.

Similarly, in block 27 form

signal and

27

proportional 18a

Uo

I

At six o'clock

by amplifying the signal and

time. Set by setter 9 constant

voltage Uq proportional to diJ

R

considering that the operator expression

namic parameter a. In the square 20, it is replaced by multiplication by the magnitude of pe 23 to form a signal V, proportional to the magnitude a.

In block 18 multiply multiply

those. form proportional magnitudes Uj and Uq

U | g signal is not a. In the I1 scale unit, the signal is amplified and

those. the output signal of the block 11 U ,, is rationally Pa.

In block 19, the signals U are multiplied

25

18

eleven times

about 27

constant value is equal to this constant, we show the correctness of the expression (5) for a given composition and connection diagrams of blocks 6, 8, 9, 11, 12, 13, 15, 17, 21 and 22. I

We make a sequential syst

2Q equations, starting from the output X ((output of block 13) to the input U (t) (output of block 20).

and. i.e. form a signal U, g proportional to the value of 18a, a, j. Subtract in block 29 from the signal and. i.e. output voltage is proportional to the value (1 8a ;, а2-1 1а

In block 32, the signal AND from block 29 is divided by the signal U from block 25, i.e. A voltage is formed at the output of the block 32, proportional to the parameter K ", determined by expression (9). Subtracted in block 30 from a sigform form

signal U

proportional to the magnitude (For, -a). Divided in block 31 Ujo signal

to signal U, i.e.

form a signal 45

U- |, proportional to the parameter Kg ,, determined by the excretion (8).

The work in cooperation of the blocks 21, 22,11,12,15,17,8,9, 6 and 13 will be described in the following way.50

These blocks constitute a dynamic filtering subsystem, the input of which is the output signal U, proportional to the voltage generated in accordance with (1 1) by the expression 55

t

) K (t) + K, J (t) dt, (12)

ABOUT

where (t) is defined by (11).

1562 8

The output of the dynamic filter is the signal U ,, from the output of block 13, proportional to the parameter g x (t). The relationship between the specified values of U (t), X (t),), X (t), T, K, K g, and k. Is given by the integra system

the differential equation of equations (11) and the transfer function of the filter (5).

10 The transfer function of the dynamic filter W (j) (P) is determined by the expression (5), which is proportional to the ratio of the output X (P) to the operator expression of the filter's 15 value, i.e. J (p.

Taking into account that the operator description formally replaces the time t with the operator P, i.e. U (t) is written as (P), and also that the integration

J

R

Bearing in mind that the statement is expressed by multiplying by

25

) h5

constant value is equal to this constant, we show the correctness of expression (5) for a given composition and connection scheme of blocks 6, 8, 9, 11, 12, 13, 15, 17, 21 and 22. I

We make a sequential system

2Q equations, starting from the output X (t) (output of block 13) to the input U (t) (output of block 20).

In accordance with FIG. 3

and „(P) U6 (P) U ,, (P) and„ (P) T, since U (P) T (P) T const;

and „(P) U ,, (P) -i;

g

and ,, (Р) and, о (Р) -); (13)

U2o (P) U (P);

U ,, (P) U, 5 (P) + U ,, (P);

U, 5 (P) U ,, (P) -U, (P) U ,, (P) ,. a

since Ug (P) a (P) a const;

and „(P) U ,,, (P) .Ug (P) U, 2 (P) .a ,,

since Ug (P) a, (P) a, const;

J, i (P) U ,, (P).

Sequentially, we substitute the values of the signals from the system of equations into the first equation

(R)

and, (p) and „(p) T

 U2, (P) 5

(14)

whence U2, (P) PU ,, (P)

(15)

and „(P) U (P) - U ,, (P) U (P) - U, f (P) - U ,, (P) U (P) -, (P) -U ,, (P ) - a, U (P) - ,, (P) - U ,, (P)

(sixteen)

91331

Equated to (15) and (16), we obtain

Pu, DR) and (P) -a (and, (P) - - | - and "(P)), (17) 5

from where

and (P) W () -. ,

Taking into account that X (P) U, | (P) T, we obtain

TR

(18)

x (P) and (p) rt; -; p -; .

HJUI by definition

,, (p) - yp -tr

 t and (P) P + agP + and i. Expression (5) describes the functions of these blocks, consisting of. and nname filter.

T. UxUM, with the appearance of the control signal IKt at the output of block 20), the output of block 13 is formed. X (t).

In block 1 of comparison, the magnitude of the error (t) is determined by the expression (j)

fc (ty X (t) - X (t) - (t)) iyTf g Find out from the signal U signals and, and and ,. The signal b is multiplied in block 1A by the signal, i.e. output 1 signal and 4 blocks 14 proportional to the value (t). Integrated in block 10 U, and multiplied in block 16 by the signal U-j, i.e. the output of block 16 form a signal proportional to the value of (t) dt.

Sign. The plumes and, and and, are added up in block 20, i.e. at its output a UOT signal forms a Ujo signal proportional to ll (t) in expression (12). The control signal and (-t) is fed to the input of the dynamic | 1 filter, i.e. to the arithmetic addition unit 21 for generating a signal X (p (t) at the output of the unit 13, as well as to the actuator 4.

The actuator 4 changes the position of the valve 5, which changes the water flow in the discharge of the classifier 34.

The current pulp density signal in the power supply of the magnetic separator from sensor 1 goes to comparison unit 3 where it is first added to the signal from the first multiplication unit 13, and then compared with the specified density from unit 2. The error value from the output of unit 3 goes to block 14 and through the integrator 10 to block 16.

five

five

0

five

0 g

Q

56210

In blocks 14 and 16, the error signal is multiplied by the signals from blocks 31 and 32 divisions, respectively, and then summed up in block 20 of addition. Signals 31 and 32 divisions receive signals equal to (8) and (9), respectively, and the signal generated by addition unit 20 is determined by expression (10). It enters the actuator 4 of the valve 5, optimally changing the water flow in the discharge of the classifier, preventing the occurrence of emergency oscillations, stabilizing the density of the pulp in the separator feed.

At the same time, the control signal from the output of the addition unit 20 is supplied to the addition unit 21, where it is algebraically added to the signal from the addition unit 22 with a minus sign. The signal at the output of block 22 is formed by blocks 11, 12, 8, 9, 15, 17 and 22 so that the signal after the second integrator 11 multiplied in block 13 multiplied by the parameter T value set by setpoint 6 is equal to (5). The values of a, and a are set by the controllers B and 9 reference signals-} 1al.

The set value of the parameter K, set by the setting unit 7, is fed successively to the scaling units 24 and 25 with the scaling factors 3 and 9, respectively.

The specified value of the parameter a is fed to a quadrant, from the output of which the signal equal to a is fed to the multiplication unit 18, in which it is multiplied by the value of a ,, from the setter 9.

t

The signal from the output of block 18, equal ai, is fed to the scaling block 28 with a scaling factor equal to Hbw 11. The signal a from a setting unit 8 is fed successively to the scaling blocks 26 and 27 with scaling factors 3 and 6, respectively, and in the multiplication unit 19 the signal equal to 18 a ,, is multiplied by the value of a2 from setpoint 9.

In subtraction block 29, the numerator of expression (9) is determined, which in division block 32 is divided by the value 27K from block 25. The signal formed by expression (9) goes to block 16. In a similar way, the signal arriving from output 3 by dividing by block IA multiplication.

Thus, the device controls the water flow rate in the discharge of the classifier and the enrichment process as a whole, not allowing emergency fluctuations in the content of the finished product in the feed, middling and tailings of the magnetic separator. Dispersion of oscillations of a granular composition decreases by 253156212

30%, increases the overall productivity of the cycle on the finished product. Controlling the process of magnetic g separation using the proposed device provides a step-by-step performance of 0.4%, increasing the content of the useful component in the product by 0.1% while simultaneously reducing the content of the useful component in the tails by 0.25%.

Pj / m

1315 1550 1325 1300

120

Tg

-

t 2 300 360 t, c

9lt2.1

msec 120 180 300 360 t, c

9g.1

On to / 1 assafak

But. enrichment

9g

Claims (1)

DEVICE FOR AUTOMATIC CONTROL OF MAGNETIC SEPARATION PROCESS, including a sensor and pulp density adjuster in the magnetic separation feed 'connected to the input of the comparison unit, an actuator and an electric shutter for water flow into the classifier drain, characterized in that, in order to improve the quality of the concentrate by eliminating overshoot, it is equipped with four reference signal adjusters, three integrators, seven multiplication blocks, three blocks of algebraic addition, a quadrator, five large blocks, two subtraction blocks, two division blocks, and the output of the first reference signal generator is connected to the first input of the first multiplication block, the output of which is connected to the third input of the comparison unit, the output of the density sensor is connected to the second input, and the output of the comparison unit is connected to the input of the first integrator and the first input of the second multiplication unit, the output of which is connected to the first input of the first addition unit, the output of which is connected to the input of the actuator and the first input of the second addition unit, the output of which is connected to the input of the second integrator, the output of which is connected to the second input of the first multiplication unit, the input of the third integrator and the first input of the third multiplication unit, the output of which is connected to the first input of the third addition unit, the output of which is connected to the second input of the second addition unit, the output of the first the integrator is connected to the first input of the fourth multiplication unit, the output of which is connected to the second input of the first addition unit, the output of the second reference signal generator is connected to the input of the first large-scale a lock whose output is connected to the first input of the first division block, the output of which is connected to the second input of the fourth multiplication block, the output of the third reference signal master is connected to the input of the third scale block and to the first input of the fifth multiplication block, the second input of which is connected to the output of the third integrator, and the output of the fifth multiplication block is connected to the second input of the third addition block, the output of the fourth reference signal generator is connected to the second input of the third multiplication block, the quadrator input, the first input of the multiplication block and the first input of the seventh multiplication block, the output of which is connected to the first input of the first subtraction block, the output of which is connected to the second input of the second, „> 1331562 ΛΊ 133 division block, the quadrator output is connected to the second input of the sixth multiplication block and the first input of the second subtraction block, the output of which is connected to the second input of the first division block, the output of which is connected to the second input of the second multiplication block, the output of the third scale block 562 is connected to the second input of the second subtraction block and the input of the fourth scale block, the output of which is connected to the second input of the seventh multiplication block, the output of the sixth multiplication block is connected to the input of the fifth scale block, the output of which is connected to the second input of the first subtraction block. , 1