SU1594504A2 - Device for controlling temperature - Google Patents

Abstract

The invention relates to automation and is intended to control and stabilize the temperature of various physical objects, in particular, at cryogenic temperatures in vapors of a cryogenic liquid, such as gels. The purpose of the invention is to simplify the operation of the device by automatically switching from one value of the gas flow rate to another. For this, the temperature control device further comprises a gas flow regulator 26, which, depending on the state of the source 24 of the reference signals and the comparator unit 25, changes the gas flow of the electrodynamic valve 3. 2 Il.

Description

The invention relates to automation, is intended to control and stabilize the temperatures of various physical objects, in particular, at cryogenic temperatures in vapors of a cryogenic liquid, for example, liquid gels, and is an improvement to the device according to the author. No. 1315960.

The purpose of the invention is to simplify the operation of the device.

FIG. 1 shows a block diagram of the device; in fig. 2 — Valve flow control with three valves.

The device stabilizes the temperature of the object 1, for example, the temperature of the heat chamber, and contains the actuator 2, electrodynamic valve 3, temperature sensor 4, reference element 5, temperature setpoint 6, amplifier 7, analog-to-digital converter 8, first switch 9, registers 10 and 11 adder 12, ko-; pre-pulse converter 13, tare module 14 and 15, switches 16 and 17, second switch 18, reversible counter 19, register 20, pulse / pulse converters 21 and 22,

synchronization unit 23, reference signal source 24, comparator unit 25 and gas flow control valve 26.

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The gas flow controller 26 is structurally a sealed body 27 in which electromagnets 28 are located, springs 29 clamping locking elements 30 against the end of passage channels 31, whose cross section is determined by the position of the needles 32.. The device works as follows.

The temperature setting device 6 establishes the voltage corresponding to the required temperature and the postive one of the inputs of the comparison element 5, the second input of which from the temperature sensor 4 receives the voltage corresponding to the actual actual temperature of the object 1. The output voltage of the element 5 through the amplifier 7 to the input of the analog-digital converter 8, which converts the error voltage into alternating error code X пТ J. The formation of the control action on the heater and EDC occurs during the period Elenny two cshsla - error and derivative.

In the error cycle, block 23 puts into operation a chain of the series-connected switch 9, converter 13, modulator 14, switch 18, and reversing counter 19. From analog-digital converter 8, error code X, GpT through the mutator 9 enters the input of converter 13 which forms a time interval of a long time5 proportional to the value of the code. The error code also enters through register 10 into register 11. In modulator 14, the time interval is filled with pulses with the frequency set by switch 16. Adjusting this frequency allows the gain on the error channel K to be varied.

At the same time, the sign bit of the error code goes from analog-digital converter 8 to the forward input switch 18 switch. Depending on the value of this bit (O or 1), switch 18 transmits pulses from the modulator 14 to the summing or subtracting input of the reversible counter 19 The counter state is changed by an amount proportional to the error code.

In the cycle of the derived block 23, the follower chain includes

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but included registers 10 and 11, adder 12, switch 9, converter 13, modulator 15, switch 18, reversible counter 19. The inputs of adder 12 come from register 10, the code of the current error value X пТ, and from .register 11 - the code of the previous one error value, X (n-1) TJ. Adder 12 calculates the difference (derivative) between the current error code value and the previous value of this code. The derivative code X π-X (n-l) Tj through the switch 9 comes into the converter 13, where it is converted into a time interval whose duration is proportional to the value of the derivative code. In modulator 15, the time interval is filled with pulses with a frequency set by switch 17. By varying this frequency, the transmission coefficient over the derivative channel K is changed.

The sign bit of the derivative code from the adder 12 is fed to the control input of the switch 18. Depending on the value of this bit, the switch 18 transmits pulses from the modulator 15 to the summing or reading input of the reversible counter. The state of counter 19 is changed and is proportional to the derivative code.

Thus, in the counter 19 of the form-IvI and pipers, the control action code Y pT Y (p-1) K X pT + + -X (p-1) T, which is rewritten into register 2.0.

The up / down counter 19. Which works without zeroing, performs the function of a digital integrator,

Depending on the magnitude and sign of the control code of the Y pT3 transducer, the transducer 21 or 22 produces heating or cooling control pulses, the duration of which is proportional to the code of the control action. These impulses include one of the executive bodies; electric heater 2 or electrodynamic valve 3.

At the same time, the voltage corresponding to a predetermined temperature, from the sensor 6, is supplied to the comparators block 25, to the second input of which the reference voltage from the source of 24 reference signals arrives. The magnitude of the differential voltage controls the variation in the flow area of the gas flow control valve by activating a specific set of valves, i.e. regulates the gas flow in amplitude. The gas flow regulator 26 is connected in series with the electrodynamic valve 3, which performs latitudinal modulation.

As shown by experimental studies, to ensure operation in a wide range of cryogenic temperatures, for example, from 4.3 to 300 K in a valve gas flow controller, the optimum number of valves with fixed flow sections is equal to three. .

Thus, the proposed device provides a reduction in the time taken to reach the specified temperature of the cryostat's heat chamber with the same stability of the temperature of the object of study. This reduces the consumption of cryogenic

by automating temperature control and stabilization processes, and minimizing the effects of overshoot and temperature fluctuations.

Claims (1)

Invention Formula A device for temperature control on aut. St. 1315960, which, in order to simplify the operation of the device, introduced a valve gas flow controller, a comparators unit and a source of reference signals connected by a group of outputs to the first input of the comparators unit, the second input of which is connected to the output of the setpoint generator temperature, and the group of outputs - with the corresponding inputs of the valve gas flow regulator connected by the output to the input through the gas flow of the electrodynamic valve. nineteen Record fPfZO K device. 8, iZ / k / k 2J 0t / ff.f Phie.g