SU1675418A1 - Method of control of synthetic thread cooling process - Google Patents

Abstract

The invention relates to the automation of chemical-technological processes. The purpose of the invention is to reduce the non-uniformity of the properties of the thread along the length, which is achieved due to the fact that when adjusting the flow rate of cooling air at workplaces of the spinning machine, the temperature of the cooling air, the rate of fiber formation and the temperature of the thread 2 are taken into account.

Description

The invention relates to the automation of chemical-technological processes and can be used to control the processes of cooling filaments molded on multi-seat spinning machines.

The purpose of the invention is to reduce the unevenness of the properties of the thread along the length.

FIG. 1 shows a functional diagram of a spinning multi-seat machine; in fig. 2 shows the experimental characteristics of the spinning machine through temperature control channels.

The spinning multi-purpose machine contains from 18 to 36 spinnerets 1. Polymer streams flowing out of the spinneretter harden, combine into filaments 2 and wind on the receiving mechanism 3. The filament is cooled by air supplied from the distribution devices 4. The combination of the spinneret 1, the distribution device 4 and the receiving mechanism 3 constitutes a spinning place.

The control unit contains a control flap 5 for supplying cooling air to each spinning point and an adjusting member 6 for changing the flow rate of cooling air to the spinning machine as a whole.

The sensors 7 are installed near the filament 2 and provide a measurement of the temperature of the boundary layer of air with it. The outputs of the sensors 7 are connected to the inputs of a multichannel analog-to-digital converter 8, the output of which is connected to the input of the operating unit 9 (information distributor and driver of controlled action). To the second input of block 9 is connected to the output of block 10 of the keyboard. The output of block 9 is connected to the input of the controller 11, the output of block 10 is connected to its other input, providing input of the task. The output of the controller 11 is connected to the input of the correction unit 12. The output of the identification unit 13 is connected to the second input of the block 12, to the inputs of which are connected the outputs of the speed molding sensor 14 and the cooling air temperature 15. The output of the block 12 is connected to the input of the digital-to-analog converter 16. The input of the controller 17 is connected to the output of the block 9. One output of the block 17 connected to the printing unit 18, and the other to the input of the display unit 19.

(/

WITH

Ssg

4- x

J

The method is carried out as follows.

Using sensors 7, the temperature of the air boundary with the filament is measured at each workplace. After converting the analog signals in the converter 8, the digital signal from its output goes to the operating unit 9, which processes them in accordance with the algorithms enclosed in it and then transmits the generalized information about the deviation of the average temperature to the control unit (regulator) 11 and using the controller 17 provides information to the terminals 18 (printing unit) and 19 (the display unit, i.e., the display).

Unit 9 calculates the average temperature value by the spinning machine Qi (ri) in the / th measurement cycle and calculates the values of temperature deviations by jobs (Df, -, -,) from the calculated average value by the Qi machine ( n). In this case, in block 9, the following algorithm is implemented

0, (p) faQti / n;

(one)

D6 ,,. 0 ;; (/)Ј.( not)

Then, using the controller 17 and terminals 18 and 19, they provide recommendations to the operator for adjusting the air flow in places using the control flaps 5. At the same time, recommendations for corrections are formed by block 11 according to the algorithm

, - & (n). (3)

The change signal for cooling air flow to the machine is generated by the controller 11 according to the following algorithm.

(n) -00. (4)

In expressions (1) - (4), the notation is:

Qti is the temperature value in the / -th workplace in the i-th measurement cycle;

9i (n) is the estimate of the average temperature value over the set of workplaces n in the i-th measurement cycle; AQ, / - value of the flow / air correction after the adjusting valve in the t-th measurement cycle; Kuu, K are the coefficients for adjusting the cooling air flow rate to the machine and the workplace, respectively.

Measured by the sensors 14 and 15, the speed of forming the thread and the temperature of the cooling air are converted in block 13 from an analog value to a digital one based on the measured-by characteristics, and fed to correction block 12, where the corrected value of the control action is generated.

 9i (n)

to "кЈ-кЈ. (5)

five

0

five

where is, respectively, the correction factor, taking into account the relationship of the gain factor of the object with the deviation of air temperature on the spinning machine and the speed of forming the thread; / (, / (o-) - coefficients that take into account the effect of cooling air temperature and thread spinning speed on the temperature of the boundary layer;

 - regulator gain factor;

00 - the specified value (nominal) of the boundary with the air thread.

The value of the regulating signal is supplied from the correction unit 12 to the digital-to-analog converter 16, which outputs an analog signal to the regulator 6 for changing the flow rate of cooling air to the spinning machine. Temperature uniformity at the workplaces of the spinning machine is one of the main requirements for spinning technology. The temperature deviation of one spinning machine should not exceed ± 3 ° С for polyester fibers.

When forming filaments from the melt, a number of factors influence their thickness: cooling air temperature, fiber speed during drawing, laminariness and stability of the cooling air flow, etc.

The change in time of these indicators leads to a change in the gain of the control object K0u over the channel of the regulating effect on the actuator, which changes the flow rate of cooling air, i.e., AP-AL

The proposed method provides an increase in the quality of regulation when the cooling air temperature and fiber speed change due to parametric self-tuning of the gain of the QCK control unit. Proof of this is the dependence of the gain factor on the cooling air temperature and the fiber speed provided that they are small enough increments in the vicinity of the working air. point corresponding to the nominal temperature / and fiber speeds, having the form

Kou Kou Kf Kj

From the theory of automatic control it is known that in order to maintain the required decay of the transient in the control system, it is necessary to fulfill the condition

Kou Kyv Kb consi, (6)

where Kou.Kuu, - respectively, the gains of the control object that controls

control devices and systems;

Kt, Ku are the coefficients of the influence of air temperature and thread speed.

The condition is valid for fixed, nominal values Kou and Kg, corresponding to nominal values of temperature / air and speed V of the thread. When they change, the object magnification factor will also change. As a result, the gain of the control system is changed, which will lead to a deviation of the temperature of the thread from the specified value.

To eliminate this, a correction block with a correction factor is introduced.

K-f KЈ KЈ Kjl-Kjl. Indeed, in this case, the total coefficient of the control system is equal to K n Kwu-Kuu KwuK -KuK -Ktv) -Ktf Kly A -const;

Kelu const,

i.e. Who in this case does not depend on the temperature of the cooled air and the speed of the fiber.

Thus, the correction of costs for the workplaces of the spinneret ensures that the temperatures of the workstations are equalized, i.e., they provide equal quality of the threads for the workplaces, and taking into account the cooling air temperature on the machine and the fiber speed when adjusting the cooling air flow rate to the machine depending on the average temperature on the machine eliminates the uneven thickness of the filaments in length.

As a multichannel analog-to-digital converter (blocks 8 and 13, fig. 1), for example, the centralized control systems A701-03 or ASTRA-OZA can be used.

0

five

0

five

Primary temperature sensors can be standard resistance thermometers.

The speed of the threads is measured by the speed of rotation of the spool of finished threads, on the axis of rotation of which a conventional tachometer of any type is placed.

As an actuator on the cooling air supply line, you can use a damper equipped with electric water.

Manual actuators for workstations are located on each spinning machine.

Information processing and generation of control signals can be performed with the help of an information and control system based on the microcomputer Electronics-60, as well as with DVK-1, 2, 3, etc.

Claims (1)

Invention Formula A method for controlling the cooling process of synthetic yarns, mainly on multi-spinning machines, consisting in measuring the temperature of a formable thread over workplaces, calculating its average value and determining the deviations of measured temperature values from the average value, depending on which control effect is generated on the cooling air supply to individual workplaces and generally to the spinning machine, characterized in that, in order to reduce the non-uniformity of the properties of the thread along the length, the complementary It measures the spinning rate of the filament and the temperature of the cooling air, and the control action is adjusted for the measured parameters. / fig FIG. 2