SU1674085A1 - Device for controlling thermal conditions - Google Patents

Abstract

The invention relates to a technique for adjusting and automatically controlling the test modes of products and samples. The purpose of the invention is to improve the accuracy of regulation of a given thermal test mode. New in the invention is the introduction of blocks, allowing to take into account the effect of the dependence of the thermal conductivity of the material of the wall of the reflector on the temperature. 1 il.

Description

The invention relates to a technique for regulating and automatically controlling the thermal conditions of testing products and samples.

The purpose of the invention is to improve the accuracy of regulation of a given thermal test mode.

The drawing shows a block diagram of the device.

The device comprises a unit 1 of the heat flux absorbed by the product, the element 2 of comparison, the former 3 of the regulation law, the actuator 4 and the heat source consisting of a system of infrared heaters 5 located around the product 66 and the metal reflector 7 cooled by refrigerant 8, the first 9 and second 10 thermal converters, to which thermal sensors are mounted, mounted on a metal reflector, first differential amplifier 11, first large-scale amplifier 12, first 13. second

14 quadrants, the third differential amplifier 15, the third large-scale amplifier 16. the adder 17, the second large-scale amplifier 18 and the second differential amplifier 19.

The device works as follows.

Signal. the error from the output of the comparison element 2 is fed to the input of the regulation 3 generator, which forms the signal ly coming from one output through the second large-scale amplifier 18, in which it is converted into a signal (1U- (yo), to one of the inputs of the second differential amplifier 19, from another exit to the executive body 4, which controls the heater system 5, creating a heat flux d0, most of which goes to heat the product 6 (gi), and the other part

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absorbed by the cooling system 8 . the consumer 7, the temperature of the heated TI and cooled T2 surfaces of which are fixed by thermal sensors. The signals Ti and Ta through the first outputs of thermocouples 9 and 10 5 are fed to the first differential amplifier 11, from which the signal (Ti - Ta), converted by the first large-scale

amplifier 12 to the value of - $ - (Ti - Ta), „

goes to one of the inputs of the adder 17, the signals Ti and Ta also go to the first 13 and second 14 quadrants, from the output of which are converted to Ti2 and Ta2 go to the third differential amplifier 15, from the 15th output of which the step signal (Ti - TI) is fed to the input of the third large-scale amplifier 16 with a conversion ratio Aa-B nor -7ГГ- and then to the second input of the adder „

17, from the output of which the generalized signal is fed to the second input of the second differential amplifier 19, from the output of which the resulting signal corresponding to the heat flux goes to the second input of the comparison element 1

gi - K (1U - 1у0) Lo f-r

about C11

T2) (I-t2).

where iy is the control current;

lyo is the displacement amount at the input of the executive body, at which d0 0;

Do, B - coefficients determined on the basis of real values of A and T °;

And - the coefficient of thermal conductivity of the metal wall;

g is the wall thickness of the reflector;

K - coefficient of proportionality.

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The proposed device, by taking into account the dependence of coefficient A on temperature, makes it possible to increase the control accuracy.

Claims (1)

Apparatus of the Invention A device for regulating thermal conditions, comprising a series-connected master, a reference element, a law regulator, an actuator, a heat source made in the form of infrared heaters equipped with a cooled metal reflector, and first and second thermal converters, first and second differential amplifiers, first and second large-scale amplifiers and thermal sensors mounted on the outer and inner sides of the cooled metal reflector l and connected respectively through the first and second thermocouples to the inputs of the first differential amplifier, the output of which is connected to the input of the first large-scale amplifier, the first input of the second differential amplifier through the second large-scale amplifier connected to the output of the control law generator, and the output to the second input of the comparison unit, different The fact that, in order to increase the accuracy of controlling the given thermal conditions, the device contains an adder, a third large-scale amplifier, a third differential A primary amplifier, the first and second quadrants, the inputs of which are connected to the outputs of the first and second thermal converters, respectively, and the outputs to the inputs of the third differential amplifier, the output of which through the third large-scale amplifier is connected to the first input of the adder, to the second input of which the output of the first large-scale amplifier is connected, and the output is connected to the second input of the second differential amplifier.