RU1770951C - Device for programmable maintaining of the temperature in autoclave - Google Patents

Abstract

The invention relates to systems for monitoring, controlling and controlling thermal conditions in batch autoclaves. The purpose of the invention is to increase the accuracy of maintaining the parameters of composite materials processed in an autoclave. A device for programmatically maintaining the temperature in the autoclave during the processing of composite materials comprises: an ambient temperature sensor installed in the autoclave, connected by an output to a series-connected unit for calculating the temperature distribution in the product, a minimum selection unit, a first adder, the second input of which is connected to the output of the software temperature setter and the output - with the input of the phase detector, as well as the pressure sensor associated with the second input of the unit for calculating the temperature distribution in the product, the output connected to the inputs of the maximum selection unit, the output of the maximum selection unit is connected to the first input of the second adder, the second input of the second adder is connected to the output of the minimum selection unit, and the output is to the first output of the comparison element, the second input of which is connected to the output of the differential temperature controller, the output of the comparison element through the threshold element is connected to the Stop input of the temperature programmer, the first output of the phase detector is connected to the controller of the cooling system, and to the second output in series with a single temperature controller, a power control system and electric heater sections, a unit for calculating the temperature distribution in the product is connected to an indicator, the device also contains a series-connected temperature sensor for the product and a unit for calculating the hems of the bone model of the product, and the inputs of the unit for calculating the hems of the viscosity model of the product are connected to the outputs of the unit for calculating the temperature distribution in the product, with a pressure sensor and with a software temperature setter, outputs - with an indicator and with a third input ditch adder. 1 ill. (L C vi m o CE (I

Description

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The invention relates to control systems for controlling and regulating thermal conditions in batch autoclaves filled with high pressure gas medium and intended for carrying out complex

integrated technological process :; polymerization (curing) of composite materials (CM).

To control the temperature in autoclaves, devices that modify the input heat flux are currently used.

A device for programmatically maintaining an autoclave temperature is known (basic invention). The device contains blocks for selecting the maximum and minimum, a unit for calculating the temperature distribution in the product, a pressure sensor, regulators, comparison elements,

The disadvantage of this device is that the device does not allow more reasonably to choose the temperature of the product during manufacture (curing) and to optimize the technological cycle of molding composite materials according to the viscosity (technological) model, i.e. with a certain dependence of viscosity on temperature and with a certain dependence of the degree of curing on temperature (taking into account the pressure of the medium). The device does not provide the necessary information on the physicochemical phenomena occurring during the processing of composites, and does not allow the process to be carried out to obtain products with certain physicochemical and strength parameters.

The aim of the invention is to expand the scope of application of the device, to obtain products with desired strength characteristics, to improve the quality of temperature control of a product from CM, to save energy by optimizing a given process.

This goal is achieved in that a device containing a medium temperature sensor mounted in an autoclave, connected by an output to a series-connected unit for calculating the temperature distribution in the product, a minimum selection unit, a first comparison element, the second input of which is connected to the output of the temperature programmer, and the output with the input of the phase detector, as well as the pressure sensor connected to the second input of the unit for calculating the temperature distribution in the product, the outputs also connected to the inputs of the selection unit m maximum, the output of the maximum selection unit is connected to the first input of the second adder, the second input of the second adder is connected to the output of the minimum selection unit, and the output is to the first input of the second comparison element, the second input of which is connected to the output of the differential temperature controller, the output of the second comparison element is the threshold element is connected to the stop input of the temperature programmer, the first output of the phase detector is connected to the controller of the cooling system, and the second output is connected to the temperature controller in series s, a power control system and electric heater sections, a unit for calculating the temperature distribution in the room with an indicator), additionally contains a series-connected temperature sensor for the product and a unit for calculating the hems of the viscosity model, the other two inputs of which are connected to the outputs of the sensor and software temperature setter, respectively, and the group of inputs is connected to the group of outputs of the block for calculating the temperature distribution in the product, the output of the block for calculating the hems of the viscosity model is connected

with a signal correction input of a temperature setter of the first product of the comparison element.

The invention is illustrated in the drawing. The device contains an autoclave 1, sections of electric heaters 2, 3, a temperature sensor for product 4. a medium temperature sensor R, product 6, a heat exchanger 7, a cooling system regulator 8, a unit for calculating the hems of the viscosity model of product 9, a temperature programmer 10, a pressure sensor 11, unit for calculating the temperature distribution in the product 12, indicator 13, power control system 14, temperature controller 15, differential controller

temperature 16, a minimum selection unit 17, a maximum selection unit 18, a second adder 19, a second comparison element 20, a threshold element 21, a first comparison element 22, a phase detector 23.

The output devices 4, 7, 8, Y, 10, 11 (the main invention) are shown in a hardened form and are called a power control system 14. Electric heater sections 2, 3, temperature controller 6 and a power control system (7, 8, 9, 10 , 11) in the main invention realize No. 613800.

In the unit for calculating the temperature distribution in the product 12, a typical mathematical description of the heat transfer along the product layers is programmed (simulated), which allows to determine the temperature distribution over the depth of the product, knowing

ambient temperature ТСр and physical properties of the product. The mathematical description is made so as to obtain n temperature values along the depth of the workpiece. For the first layer, the control being solved has the form:

Ti

1

mi Ci for the first layer;

/ (QCp-Q1) dr + Ty1

GPP Sp

the last layer;

/ Qn d t + T ™ - dl

where Qcp Fcp-ed "Wed-ed (TCp-Ti) -heat flow;

TI is the temperature of the first layer;

Ty - the initial temperature of the first layer;

This is the initial temperature of the nth layer;

Tp is the temperature of the nth layer;

g-time;

C is the heat capacity of the material;

Fcp-ed - layer surface between the medium and the 1st layer;

its cp-ed is the heat transfer coefficient from the medium to the lth layer;

m is the mass of the product layer.

In the block for calculating the hems of the viscous model of product 9, a sufficiently universal heme for the viscous model is constructed, constructed according to the kinetic and viscous experiments for the processed composite material (CM)

-i7 (T, / S)

(t)

moreover, can be taken into account:

and "(, T, P)

a a (a, T)

where d) is the viscosity of the CM;

 the degree of cure KM; a - degree of conversion;

a - adhesive strength of KM;

T is the temperature of the CM in the process of heat treatment;

P is the pressure of the medium.

Equations (1) and (2) are solved in the form:

(/ 3) / nt (g)

-M- F (/) - e

dr In 77 (/ 3) +

Eq (l)

RT

where F (($) is the kinetic function;

E f) is the activation energy of the curing process;

Er) (p) is the activation energy in a viscous flow;

oo () 8) is the limiting value of viscosity at T - oo.

Equations (3) and (4) are programmed according to known experimental data and

are quite definite dependencies in relation to the material being processed.

After determining the values of), F 3), 5 g) (xp), Ec $ for various degrees of solidification of the CM, the functions u / g are calculated for arbitrary curing modes T (g) and for different heating rates.

The heme viscosity model allows calculating (obtaining), taking into account the thermal model of the product, the full viscosity profile for the conducted temperature curing mode.

Having a set of kinetic curves, experimental data for processed CMs, functional dependences of changes in the physicochemical properties of CMs, the model constantly monitors the execution of a given program and corrects it.

One of the criteria for an optimum curing mode, for example, is a predetermined KM content of the matrix or degree of conversion. The operator, given the criterion of the degree of conversion and the adhesion strength of the CM, using the viscous model hems, obtains the values of optimal viscosity, temperature rise rate, and curing temperature.

In the heme calculation block of the viscosity model 9, the calculated temperature is compared with the temperature of the program setter 10, the temperature and the LT signal is generated, which is fed to the third input of the first comparison element 22.

The temperature sensor of the article 4 is installed at a characteristic point of the processed CM product. This point can be the determining technology for processing this type of product, which is difficult to calculate using mathematical methods. The suitability of the thermocouple installation is determined by the technologist. In products with complex configuration, at the stage of technology development, n temperature sensors can be installed 4. The temperature sensor information of the product 4 is additional to the information from the temperature distribution calculation unit in the product 12.

fifteen

twenty

25

thirty

35

40

45

fifty

5

On the first comparison element 22, a difference signal is generated between the minimum temperature value in the product and the thermal regime program T embedded in the program unit 10. but taking into account the value of DTt. Depending on the magnitude of the difference, the phase detector 23 provides a signal to the temperature controller 15. or to the cooling controller 8. which

acts on the shutoff valve of the heat exchanger 7.

The device operates as follows.

The signal from the temperature sensor 5 and pressure 11 installed in the medium of the autoclave I is sent to block 12. Based on the mathematical model, block 12 generates the temperature values of different layers (from Ti to Tp) of the processed product 6. The first comparison element 22 compares the minimum temperature with the software setpoint 10 and sends this difference through a phase detector to the input of the temperature controller 15 in the temperature rise mode and to the input of the cooling controller 8 in the cooling mode. The second adder 19 tracks the difference between MAX and MIN. the temperature of the product layers and the designated difference, DT2 controls the setpoint 10. In the heating mode Ti, the temperature of the first outer layer is Ti max, and in the cooling mode Ti is minimal.

The pressure sensor 11 monitors the technical change in pressure in the autoclave during the heat treatment of the product. Depending on the magnitude of the pressure, block 12 makes an appropriate calculation of the coefficient "sr-ed. On the second adder 19, a difference signal is generated between the MAX and MIN. temperature value in the product. This difference is compared with the task of the temperature difference setter 16 АТ2 on the second comparison element 20. If the difference is greater than the allowable threshold element 21 stops the program setter 10, with an allowable difference - permission to further change programs, thereby controlling the temporary mode of the program setter 10 for obtaining a given temperature variation in the product,

Unit 9 corrects the reference value T of the temperature programmer 10 on the first reference element 22.

If block 9 carries, for example, experimental dependences / 3 t (o); / f (T); Ig rj f (Tj; o f (P), has the calculated temperature of the layers, the kinetic characteristics of KM F (/ 3), E $), then it is easy to implement software methods

Comparison of Trasch And Texler, (Trash Teksper ATkor); Tzadan & Texper (Tzadan-Texper

 ATOSH);

where Trace is the estimated temperature of the selected layer; it is calculated after a given time interval;

Texper - the temperature entered into the basic data of the model, obtained from the experimental dependences, is read at a given time interval;

Tzadan-temperature from software setpoint 10;

ATcor - temperature correction;

Atosh temperature error.

The sum of DT1 (DTkor + ATosh) arrives

to the third input of the first element of comparison 22, thereby correcting a program-changing task from program setter 10 (limit values, rate of temperature rise).

The output of the temperature controller 15 continuously changes from 0 to 5 mA, which corresponds to the need to change the power supplied to the autoclave through the power control system 14.

As power control systems, schemes proposed in USSR copyright certificates Ns 1457175, 773967, 613800 can be used.

Signals of temperature field values

products and the full viscosity profile are displayed on indicator 13.

The signal from the detector detector 23 enters the temperature controller 15 when the reference signal is greater than Tmin and to the system controller

cooling 8 at a reference signal less than Cmin. In the phase detector 23, a deadband can be set when none of the controllers is working. The controller 8 changes the flow rate of the coolant through the heat exchanger 7. The presence of a temperature sensor 4 in the product, installed at a characteristic point, as well as a unit for calculating the hems of the viscous model of the product, allows processing the curing products to optimally execute the curing and heating program for the whole volume of the product, check and automatically ensure the permissible temperature differences,

carry out the curing process at the required viscosity, save energy.

The expansion of the scope of the device is achieved due to the possibility

programming the process during the autoclave of complex technological modes of curing KM, processing products of various configurations.

The device can be implemented on

domestic electronic devices. For example, temperature sensors 4, 5 - a thermocouple with a converter Ш 705; a cooling system controller 8 and a temperature controller 15 - a controller R-17, PAC (01), a software temperature controller 10 and a temperature differential sensor 16 — PRZ (24), KPZ-L; pressure sensor - 11 - SAPPHIRE 22 CI; device for selecting MIN, MAX., 17, 18 - SEL units (41); adder 19 - SUM (30); Comparative Element 20, 22 - CAD (31); signaling device 21-ULO (50); 23-SUM phase detector (30) with corresponding restriction settings; power control system 14-PNTT-250-330; indicator 13 - display Dimikont, personal computer, KSU-2; blocks 9 and 12 implement the solution of systems of differential equations on the Remicont, Dimekont-INTEGR, DIF, MULTIPLE, SUM algorithms or with the help of a personal computer with an ADC at the inputs,

The proposed device can be used in automation schemes of complex technological processes for the curing of expensive products from composite materials carried out in autoclaves with electric heating.

Claims (1)

SUMMARY OF THE INVENTION A device for programmatically maintaining an autoclave temperature by auth. St. No. 1711130, characterized in that, in order to increase the accuracy of maintaining the parameters of products made of autoclave made of composite materials, the device is equipped with series-connected temperature sensor of the product and a unit for calculating the hems of the viscosity model of the product, the other two inputs of which are connected to the outputs of the pressure sensor and program setter, respectively temperature, and the group of inputs is connected to the group of outputs of the block for calculating the temperature distribution in the product, the output of the block for calculating the hems of the viscosity model is connected to the course of correction of the signal of the temperature programmer of the first comparison element.