SU864261A1 - Proportional temperature control - Google Patents

Description

(54) PROPORTIONAL TEMPERATURE REGULATOR

I

The invention relates to automatic regulation, in particular, to devices designed to automatically maintain the temperature regimes of resistance furnaces in laboratory and industrial installations.

Known proportional thyristor regulators. Temperatures 1, 2.

However, these controllers use constructively complex control signal conversion circuits to trigger pulses, including multivibrators, Schmidt triggers, sawtooth generators, blocking oscillators, magnetic amplifiers that complicate tuning and operation of devices.

The closest in technical essence to the present invention is a thermostat, which contains a temperature sensor connected via a dc amplifier to the input of a zero-body regulating element.

as well as a sawtooth generator and sequentially connected clock pulse shaper, coincidence element and control pulse shaper 3.

In this thermostat, the sensor signal is amplified by a DC amplifier and fed to a null organ, which compares the signals from

to a DC amplifier and a special sawtooth generator. The zero-body imparts rectangular pulses, the duration of which depends on the ratio of the input

IS signals, and the frequency is determined by a sawtooth generator.

These pulses are fed into a coincidence circuit, where they are compared with synchronized pulses, to be generated by the sync pulse generator. The output of the coincidence circuit is fed to the trigger pulse driver. Short start pulses are applied to the thyristor control electrodes. However, this device is complicated and has a limited scope. The purpose of the invention is to simplify and expand the scope. The goal is achieved by the fact that a proportional thermostat containing a temperature sensor, a null organ, an amplifier, a driver and an executive thyristor connected in series with the load, contains a mode switch, a variable resistor and a diode, and a rectifying diode, and The switching diode is connected in series with the executive thyristor, and its anode and cathode are connected respectively to the first and second fixed contacts of the mode switch p The shunt diode anode is connected to the cathode of the executive thyristor and the fixed pin of the shunt variable resistor, the motor of which is connected to the moving contact of the operating mode switch, the third fixed pin of which is connected to the cathode of the shunt diode. . FIG. 1 shows a circuit diagram of a proportional thermostat; in fig. Figure 2 shows voltage diagrams and currents in the corresponding circuit elements. Proportional thermostat contains temperature sensor 1, null organ 2, amplifier 3, driver 4, thyratron 5, anodic resistor 6, cathode resistor 7 and capacitor 8, thyristor 9, rectifier and shunt diodes 10 and 11, respectively shunt and variable resistor 12 and switch 13 modes of operation and load 14. The regulator operates as follows. The error signal (Fig. 1) is fed to the input of the amplifier 3 through the null organ 2, from which it is fed to the imaging unit 4. The imaging unit 4 provides for receiving a short pulse with a cr

Claims (3)

At the time of the beginning of the positive half-wave, the voltage from amplifier 3 is low and 12 and the value of the current of the heater is determined only by the value of its resistance. A power thyratron 5, resistors 6, 7, and a capacitor 8 (Fig. 1) When a negative voltage half-wave is applied to the grid of the thyratron 5 from the amplifier 3, the thyratron 5 is locked, and the capacitor 8 is charged through a large resistor 6. the positive half-wave of the thyratron 5 opens, and the capacitor 8 is quickly discharged through a small resistor 7 compared to 6 (Figs. 2, 3). A short start pulse (Fig. 2, 4) is applied to the control electrode of the thyristor 9 and opens it (section 2-3 of Fig. 2, 5). The thyristor 9 remains in the open state until the end of the positive half-wave voltage supplying the power circuit (section 3-4 of Fig. 2, 5). The effective value of the current in the load 14, which determines the temperature of the resistance furnace, depends on the time during which the thyristor 9 is open. Diodes IO and 11 and a resistor 12 are introduced into the power circuit of the proportional thermostat. In this case, three modes of operation of the thermostat power circuit are implemented, which are defined by the positions of the switch 13 modes of operation - ab, bv, vg. (Fig. 2.6, 2.7, 2.8). The adjustable part of the current is shown by hatching. In all three switch positions of the 13 operating modes, the time diagrams of the instantaneous value of the load current 14 (1 c) in the positive half period are the same. At section -1-2, the thyristor 9 is locked, and the value of 1c is determined by the total resistance of the resistor 12 and the load resistance 14. At section 2-4, the open thyristor shunts the resistor 12 and the value 1. is determined only by the load resistance value 14. V negative half-period the supply voltage (section 4-5) at the position of the switch ab load current is absent; at position (5-in value of load heater 14 current is determined by total resistance of resistor 12 and load resistance 14; finally, at position 2 diode 11 shunts resistor Ratio unregulated to adjustable component of effective current load minimum in position a and maximum in position 2 Variable resistor 12 allows this ratio to be smoothly varied. Using a proportional thermostat allows you to expand the range of controlled temperatures by changing the ratio between controlled and n Adjustable load current component Formula of the invention Proportional thermostat containing sequentially connected temperature sensor, zero-organ, amplifier, driver and executive thyristor connected in series with the load, in order to simplify and expand the area applications, it contains a switch of 16 modes of operation, a shunt variable resistor and a diode, as well as a rectifying diode, and the forward diode is connected in series with the executive thyristor, and one and its cathode are connected respectively to the first and second fixed contacts of the mode switch, the shunt diode anode is connected to the cathode of the executive thyristor and the fixed terminal of the shunt variable resistor, the slider of which is connected to the movable contact of the mode switch, the third fixed contact of which is connected to the cathode of the shunt diode. Sources of information taken into account during the examination 1. USSR author's certificate No. 356631, cl. G 05 O 23/24, 1972. 2. USSR author's certificate number 480061, cl. G 05 D 23/24, 1973. 3. USSR author's certificate number 491123, cl. G 05 O 23/19, 1974 (prototype). /./ f n and, 23 Ujm rH Ih zd 1.5 / v oS Z6 In // Ih 8 2.6