SU408171A1 - DEVICE FOR MULTIPLE-POINT CONTROL TEMPERATURE - Google Patents

Description

one

This invention relates to instrumentation engineering and is intended for multipoint temperature control in various industries.

Devices for multipoint temperature control are known, comprising thermal sensors connected by contacts of a program switch with secondary devices, light and sound signaling units, and a power source. The audio signal conditioning unit of these devices does not provide the required reliability.

The proposed device differs from the known ones in order to increase reliability, the audible alarm unit is made in the form of a series-connected sound source, an open button and a thyristor shunted by resistors through the contacts of the secondary devices, and the control of the thyristor circuit is connected to the minus terminal of the source power through a parallel RC circuit.

FIG. 1 is a schematic diagram of a set of one secondary device with thermal sensors; in fig. 2 is a schematic diagram of a light signaling unit; in fig. 3 - the basic circuit of the sound alarm unit; in fig. 4 is a schematic diagram of a software switch.

The temperature control set consists of temperature sensors 1-10 connected by contacts P1-P10 of the executive relays of the program switch to the secondary device 11.

The light signaling circuit consists of signal lamps 12-21, switched on by the same P1-Ryu contacts of the same executive relay.

The basic sound signal forming circuit includes a bell 22 connected in series with the disconnecting button 23 to the anode circuit of the thyristor 24, as well as resistors 25-28, one of which is connected in series at the circuit input to the negative electrode circuit of the power supply and is connected in parallel through the control capacitor 29 The second thyristor circuit 24, and other resistors are connected through the output contacts 51-VZ secondary devices 11.

The program switch consists of a synchronous motor 30, on the input shaft of which a pulley 31 is mounted, a mixing transformer converter, the movable core 32 of which is provided with an excitation winding 33 and mechanically connected to the pulley 31. Transformer output windings 34, 35 through rectifying diodes 36, 37 , variable resistors 38-47 are connected to the control, and thyristor circuits 48-57 with windings I1-PIO in the anode circuits connected by a logical block through the output contacts. A temperature-sensitive resistor 58 is included in the common line of control circuits of the thyristor unit to compensate for the temperature error of the thyristors. The synchronous motor 30 is connected to the AC circuit, and the thyristor unit is connected to the DC circuit.

The principle of operation of the device is that when measuring the temperature, the temperature sensors I-10 are connected in series to the secondary device 11 by closing the contacts P1-I10 of the software switch. At the same time, the corresponding signal lamp 12-21 is switched on, with the help of which the point at which the temperature is measured at the moment is determined.

The diagram shows one secondary device complete with a group of sensors. However, the device is designed simultaneously for several secondary devices that work in combination with various types of sensors.

As shown in FIG. 3, the output contacts of these secondary devices are connected in series with resistors 26-28.

If the temperature changes beyond the limit parameters at any section, then the corresponding secondary device closes its contact in the circuit of one of the resistors 26-28, which will lead to the inclusion of the thyristor 24 with the ring 22 in the anode circuit. The signal is removed by opening the circuit with button 23.

The thyristor is turned on as follows. Since the thyristor is turned on at the input of the entire alarm system, at the moment of closing one of the contacts (i.e., at the moment of transient), a sufficient current flows through the capacitor 29 to turn on the thyristor. The thyristor remains switched on until the anode circuit button opens it.

The principle of the software switch is based on the fact that after applying voltage to the circuit, the synchronous motor 30 rotates the tongue 31 and causes the core 32 to reciprocate. Moving the core with the excitation winding 33 relative to the output windings 34, 35 leads to a change in the output signals of these windings.

A change in the signals at the output of the windings causes the thyristors 48-57 to be connected in series with the windings of the execution relays P1-H10 in the anode circuits. The switching intervals of each thyristor

are adjusted by varying the resistance of the resistors 38-47.

The inclusion of the closing contacts of the previous relays into the control electrodes of the thyristors of the subsequent relays and the inclusion of the opening contacts of the subsequent relays into the anode circuits of the thyristors of the previous relays provides a sequential switching program. A software switch allows simultaneous control of several sets of secondary devices.

Subject invention

A device for multipoint temperature control, comprising temperature sensors connected by contacts of a program switch with secondary devices, light and sound signaling units and a power source, characterized in that, in order to increase reliability, the sound signaling unit is designed as a sequentially connected sound source,

a disconnecting button and a thyristor, which are triggered by resistors through the contacts of the secondary devices, and the thyristor control circuits are connected to the negative terminal of the power source through a parallel RC circuit.