SU840839A1

SU840839A1 - Temperature measuring device

Info

Publication number: SU840839A1
Application number: SU792821081A
Authority: SU
Inventors: Иван Федорович Первушкин; Станислав Павлович Степаненко; Галина Алексеевна Кондратова; Николай Григорьевич Грицун
Original assignee: Украинский Государственный Проектно- Технологический И Экспериментальныйинститут "Укроргстанкинпром"
Priority date: 1979-09-28
Filing date: 1979-09-28
Publication date: 1981-06-23

Description

II

Изобретение относитс к устройствам- реализующим компенсационный метод измерени температуры и может быть использовано, например, в схемах автоматического регулировани температуры электрических печей.The invention relates to devices that implement a compensation method for measuring temperature and can be used, for example, in automatic temperature control circuits of electric furnaces.

Известно устройство дл измерени температуры, содержащее термопару, ТЭДС, которойсравниваетс с падением нап1р жени на сопротивлении, включенном в цепь батареи, последовательно с которым включен милливольтметр D1.A device for measuring temperature is known, which contains a thermocouple, TEDS, which is equal to the drop in voltage across a resistance connected to a battery circuit in series with which a milli-volt-meter D1 is connected.

Недостатком известного устройства вл етс наличие в нем миллиамперметра , который может дать точность измерени максимум 0,5%.A disadvantage of the known device is the presence in it of a milliammeter, which can give a measurement accuracy of at most 0.5%.

Наиболее близким к предлагаемому техническим решением вл етс устройство дл регулировани температуры, содержащее нуль-прибор, реохорд, нормальный элемент Вестона, эталонное со противление, переключатель, реостат и аккумул тор Г21.Closest to the proposed technical solution is a device for temperature control, containing a null device, a reohord, a normal Weston element, a reference resistance, a switch, a rheostat and a G21 battery.

Однако с изменением температуры на сопротивлении сравнени понижаетс точность измерени температуры, наличие в г компенсационной цепи батареи (источника.посто нного тока)усложн ет конструкцию устройства. Дл проверки величины тока в компенсационной цепи необходимо иметь нормальный элемент Вестона и осуществл ть эту проверку минимума 1 раз в сутки, что усложн ет обслуживание и уменьшает надежность устройства. В известном устройстве отсутствует автоматическа выдача сигнала на объект регулировани при изменении величины температуры в измер емом объекте.However, with a change in temperature on the resistance of the comparison, the accuracy of temperature measurement decreases, the presence in g of a battery compensation circuit (a source of direct current) complicates the design of the device. To check the amount of current in the compensation circuit, it is necessary to have a normal Weston element and perform this check at least 1 time per day, which complicates maintenance and reduces the reliability of the device. In the known device, there is no automatic output of a signal to the control object when the temperature value changes in the measured object.

Цель изобретени - повышение точности и надежности измерени температуры .The purpose of the invention is to improve the accuracy and reliability of temperature measurement.

Claims

The goal is achieved by the fact that a temperature measuring device containing a DC source, a voltage divider connected to it, and a temperature sensor connected by a single output to the middle point of the voltage divider, contains an insulated gate field effect transistor connected via limiting resistors to the poles of the power source, and the gate to the second output of the temperature sensor. The drawing shows a diagram of the proposed device. The device for measuring temperature contains a source of direct current 1, a voltage divider 2 consisting of series-connected resistors I-3 and a zener diode 4 parallel to which is connected a potentiometer .5, a temperature sensor b and an FET 7 with an insulated gate. The device operates as follows. in a way. From a source of direct current I, the voltage goes to a divider 2 to a voltage that is used to stabilize the voltage taken from Zener diode 4 by potentiometer 5. When the magnitude of the network voltage is changed, the voltage on potentiometer 5 remains almost unchanged, i.e. a well-defined predetermined voltage is always maintained. Thermocouple power is compared to a voltage drop across potentiometer 5. An FET 7 with an insulated gate operating at a thermostable point is provided to amplify the resulting voltage. Moreover, the dependence of the variation of the drain current in the field effect transistor 7 on the temperature is determined by the contact potential difference of the pn junction and the change in the mobility of the main carriers in the channel. As the temperature rises, the contact potential difference decreases, the channel resistance drops, and the current increases. with . On the other hand, temperature increase leads to a decrease in carrier mobility in the channel and a decrease in the drain current. Under certain conditions, the effect of these two factors is mutually compensated, and the drain current of the field-effect transistor does not depend on temperature. If the thermoelement cold junction is not heated, then the positive potential taken from the Zener diode 4 through the temperature sensor 6 is applied to the gate of the field-effect transistor 7, which opens, providing a positive potential at the output, which is fed to the control object. As the cold spa temperature sensor 6 heats up, thermal temperature occurs, which is directed opposite to the positive potential removed from voltage divider 2. Negative potential is applied to the gate of the polar transistor 7. Thus, a temperature measuring device makes it possible to increase the accuracy and reliability of temperature measurement while simultaneously feeding a signal to the control object. The invention The device for measuring the temperature, containing a source of direct current, a voltage divider connected to it, and a temperature sensor connected to a single point at the midpoint of the voltage divider, so as to increase the accuracy and reliability of the device , it contains an insulated-gate field-effect transistor, the drain and the source of which are connected via limiting resistors to the poles of the power source, and the gate to the second output of the temperature sensor. Sources of information taken into account in the examination 1. Svenchansky AD and others. Automatic regulation of furnaces. M.-L., Energie, 1965, p.65, fig.1-23a.

2. Svenchansky A.D. and others. Automatic regulation of electric furnaces. M.-L., Energie, 1965, p.65, fig.1-23b (prototype).

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