SU1318999A1 - Device for controlling temperature - Google Patents

Abstract

The invention relates to an automatic temperature control technique and can be applied to various technological processes. The device contains a comparator with a sensor and a setpoint inlet temperature and is synchronized with the network through the first pulse shaper and element I, while to reduce the level of interference and increase reliability, it contains two phase-shifting elements and a second driver that provides through the / 5-trigger and optocoupler switching on the control thyristors with the minimum amplitude of the light voltage and amplitude-phase control of the thyristors. 2 Il. (С с о о 00 со со со

Description

The invention relates to automatic temperature control and can be used to maintain the temperature regime of vulcanizers in the shoe industry.

The purpose of the invention is to reduce the noise level and increase the reliability of the device.

FIG. 1 shows a diagram of the device; in fig. 2 - time diagrams. For us and his work.

The device contains a temperature sensor 1, setpoint 2, comparator 3, element 4, the first driver 5 pulses, phase shifting elements 6, the second driver 7 pulses, / 5 flip-flop 8, resistive optocoupler 9, thyristor 10, load 11 and the transformer 12.

The device works as follows.

When the device is turned on, the voltage from the output of the temperature sensor 1 (f / o,) is less than the set point voltage (t / uuxa), the voltage of the logical unit is set at the output of the comparator 3. This voltage is applied to one of the inputs of the element 4. At the same time as the device is turned on with the corresponding windings of the transformer 12, the inputs of the pulse shaper 5 are energized with the frequency of the supply network with amplitude Us. At the moment when the input voltage of the shaper of 5 pulses is equal to zero, i.e. when the phase is 0 or 180 °, positive pulses appear at the output of the shaper of 5 pulses. These pulses arrive at the other input of the element 4. At the moments of simultaneous arrival at the inputs of the element 4, the voltage of the logical unit from the output of the comparator 3 and the pulses from the driver 5 pulses, the element 4 sets the output level RS-trigger of the logical unit. In this case, the optocoupler 9 is activated and the control inputs of the thyristors 10 are supplied with voltage from the phase-shifting elements 6.

From the output of the phase shift, its power supply 6 PA, the corresponding inputs of the second shaper 7 pulses of the optocoupler 9 and the outputs of the thyristors 10 are energized, which has the form

U ,, (2 (f, t + (f),

where φ is the phase shift introduced by the phase-shifting elements 6. At times of equal to zero supply voltage, the voltage from the output of the phase-shifting elements 6

U. yhb (4) "2 | 51psr |.

This voltage is fed through the optocoupler 9 to the control inputs of the thyristors 10, the thyristors open, and alternating voltage flows through the heater 11.

At the moments when the pulsating voltage from the output of the phase-shifting elements 6 is equal to zero, the pulse shaper 7 converts the 5-flip-flop 8 to the zero state.

five

g

0-zg

0

0

45

0

five

the optocoupler 9 is activated, the voltage amplitude at the control electrodes of the thyristors 10 decreases and the thyristors close, disconnecting the load from the supply line.

When the object reaches the desired temperature,. the voltage module from the output of the temperature sensor 1 becomes greater. the voltage module from the output of the setting device 2

out: If, b, x2l.

As a result of this, the voltage is set at the output of the compressor unit, which corresponds to the logic zero level.

Thus, at the output of the element 4, a logical level of "1" is established, and at the output of a 5-flip-flop, a level of logical zero. The voltage amplitude at the control electrodes of the thyristors 10 is reduced and the supply voltage is not applied to the load. The temperature of the object no longer increases.

The best results are obtained when cf is equal to 60-120 °. Thus, the use of new nodes and new connections favorably distinguishes the proposed device from the well-known, since. it ensures a reduction in the level of interference induced in the power supply network by switching on the thyristors at the lowest possible voltage applied to it; increases the reliability of switching on the object's heater due to the amplitude-phase control of the thyristors, and also increases the electrical safety during operation of the device due to the galvanic isolation of the control and power circuits.

Claims (1)

Invention Formula A temperature control device comprising a sensor and a temperature setter, a comparator, an And / 5-flip-flop element, a first pulse shaper, connected in series to an AC network, counter-connected thyristors and a load in series, as well as a transformer whose primary winding is connected to an AC network The sensor and temperature setpoint device are connected to the inputs of the comparator, the output of which is connected to one of the inputs of the element I, the other input of which is connected to the output of the first pulse generator, with a single input from one of the secondary windings of the transformer, and the output of the element I is connected to the S-input / 5-flip-flop, characterized in that, in order to reduce the noise level and increase reliability, two phase-shifting elements are introduced into it, the second pulse driver and a resistive optocoupler The phase-shifting elements are connected by inputs to the other secondary windings of the transformer, respectively, one of the outputs of each phase-shifting element is connected to the opposite electrodes of the thyristors, and the other outputs of the phase-shifting The matching elements are connected to the thyristor matching electrodes, respectively, through the corresponding optocoupler resistors, the inputs of the second pulse driver are connected to the outputs of one of the phase-shifting elements, and the output of the second pulse driver is connected to the R-input of the 5-trigger connected to the resistor optical input. . setb FIG.