SU824156A1 - Temperature regulating device - Google Patents

Description

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The invention relates to electrical equipment used and is intended to regulate the temperature of the heaters, as well as other parameters of the systems, in which the parameters can be regulated by varying the input power of the power supply.

A device for temperature control is known, which contains a connected temperature sensor to measure a reference unit, the first output of which is coejjfiHeH with a relay winding of a forced warm-up unit connected to an alternating voltage source with which synchronization is connected and through thyristor (th .. heater switch, moreover, the control electrodes of the thyristors of the switch are connected via rectifying elements to the flip contacts of the relay of the forced heating unit, the closure of whose contacts through the edge resistors are connected to the anode of the thyristors of the jog switch, the sawtooth generator is connected in series with the waiting blocking generator, the outputs of which are connected to the rectifier elements via the disconnecting contacts of the forced heating unit, the input is connected to the second output of the measuring and setting unit, and the output - A sawtooth generator is connected to the output of the synchronization unit R.

The disadvantage of the known device is its complexity.

The closest technical

The essence of the invention is a regulating microvoltmeter of a magnetoelectric system with a two-position photoelectric device — of type. MP1-02, based on the change in the resistance of the semiconductor resistance of the resistor, depending on the light lamp, because of which the relay contacts close or open the power supply circuit of the furnace 2,

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However, the accuracy of this device does not exceed + 1.5%, and the regulation of its two-position.

The purpose of the invention is to improve the accuracy of the device.

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The goal is achieved by the fact that a temperature control device containing a series-connected thermocouple, a compensator and a galvanometer with a light pointer, a photoresistor, one

the KOTot oro pin is connected to the negative pole of the power source, and the regulator unit, a PP transistor is inserted, the base of which is connected to the second output of the photoresistor, the collector — a positive pole of the power source, and the emitter — to the input of the regulating unit.

1 The drawing shows a device for temperature control,

The device contains a power source 1, a galvanometer 2 with a light pointer, a photoresistor 3, a pp transistor 4, a control unit 5, an electric heating furnace b, a thermocouple 7, a compensator 8.

the control unit 5 includes a variable resistor 9, a capacitor 10 dynistor 11 and thyristors 12,

The device works as follows.

From the power source 1, a 220 V alternating voltage is supplied to the power circuit of the regulating unit 5 and a pulsating voltage is applied to its control circuit, a stabilized voltage to power the galvanometer bulb 2 and a highly stabilized Hanp) voltage to the compensator 8, to which also the signal of the thermocouple 7, C is supplied. The compensator 8 nA. The galvanometer 2 supplies the difference between the emf of the thermocouple 7 and the reference voltage. The luminous spot of the galvanometer 2 is located at this point within the photoresistor 3, established near the zero position of the spot.

The power released by the electric heating furnace 6 is determined by the total resistance of the parallel-connected variable resistor 9 and transistor 4 ,. moreover, to expand the limits of variation of this resistance, the collector of transistor 4 is connected to the positive pole of the power supply 1. At maximum illumination of the photoresistor 3, its resistance is minimal, the current in the collector-base circuit is maximum, the collector-emitter junction resistance is minimal, capacitor 10 is charged for a small fraction of the half-period before opening voltage of dynistor 11, thyristor 12 is opened at the beginning of the half-period, and the power selected ema in b, maximum. An increase in temperature leads to a change in the signal7 supplied to galvanometer 2, a decrease in the illumination of the photoresistor 3, an increase in its resistance to a decrease in the current in the collector base, and, consequently, an increase in the resistance of the collector emitter, which ultimately shifts the moment of switching on the thyristors 12 to the end of the half period and decreases the output power. Thus, the AV "thematically set the power needed - to maintain the desired temperature. The reference voltage on the compensator 8 / is changed by changing the temperature in the furnace 6 in any given mode. With an unlit photoresistor 3, the power is changed by a variable resistor 9,

The accuracy of the adjustment depends to a large extent on the sensitivity of the galvanometer, the curvature of the thermo-emf of the thermocouple, and the stability of the voltage applied to the compensator. When using a type M-195/3 galvanometer and a plate-shaped thermocouple, the accuracy of control is 0.1 °. This accuracy satisfies most high-temperature experiments. Greater accuracy in. The desired temperature range is reached by using thermistors, for example zirconium dioxide, instead of a thermocouple. The absence of moving parts and current-breaking contacts makes the device reliable.

The use of simple non-deficient parts in the instrument makes it available for production in any laboratory. High accuracy, continuous adjustment and reliability of the instrument distinguishes it from known devices.

Claims (1)

Invention Formula A temperature control device containing a series-connected thermocouple, a compensator and a galvanometer with a light pointer, a photoresistor, one output of which is connected to the negative pole of the power source, and a regulating unit, characterized in that, in order to improve the accuracy of the device, p- A np transistor, the base of which is connected to the second output of the photoresistor, the collector is with a positive pole of the source, and the emitter is connected to the input of the regulating unit. Sources of information taken into account in the examination 1, USSR Author's Certificate No. 632998, cl. G p5 D 23/19, 1977. 2, ElA Shornikov, electronic instruments for control and automatic temperature control. M.-L ,, Energie, 1964, p. 38 (prototype).