Explosion-proof thermal sensors TERMODATCHIK-2 (M-TERMOSENSOR)

Explosion-proof thermal sensor TERMODATCHIK-2 is the thermal element used in measuring devices and transducers, sealed in flameproof cylindrical metal enclosure. Standard design of TERMODATCHIK-2 thermal sensor has a thread.

There are options available with a cable of the required length or with a cable mounted in explosion-proof junction box.

Possible for use for temperature control in air, liquids, or on the surfaces.

Scope of application - hazardous indoor and outdoor areas in accordance with explosion protection marking, GOST 30852.13- 2002 (IEC 60079- 14:1996) and areas susceptible to combustible dust ignition, as per GOST IEC 61241- 3- 2011, dangerous production facilities of I, II, III, IV hazard classes under supervision of Rostekhnadzor and national supervisory bodies of the CU and the CIS countries.

Thermal sensor PT100

Highly sensitive platinum resistance thermometer is used for precise measurements in thermal sensors PT100. High accuracy of sensors makes it possible to use them without additional calibration of the measurement instruments. Lower limit of measurement current is not established for PTC sensors. Measurement current to a large extent depends on the conditions of application of the sensor. Maximum recommended current for 100 Ohm: 1 mА; for 500 Ohm: 0,7 mА. Temperature sensors barely generate electric potential (inductance: < 1µH; capacity: 1 - 6 pF), have high impact and vibration strength. They are characterized by high stability of the values of the output signal. Depending on the temperature conditions, the change of resistance after 5 years of operation at 200°C is usually less than 0.04%. Change of climatic conditions and humidity fluctuations do not effect the accuracy of sensor measurements. Due to chemical stability and homogeneous structure of the applied materials, platinum temperature sensors are highly stable temperature elements.

Connection

Normally, temperature sensors are supplied with direct current with a standard 2-wire connection. To save the electric energy (a storage battery or a battery), it is possible to use alternating current as well.

Thanks to simple square-low characteristic of temperature sensors and simple linear approximation, the processing of the measured signal does not pose any problems.

Sometimes, standard 2-wire connection may lead to a loss of accuracy.

Upon customer’s request, 3 and 4-wire connection sensors are produced, which is to be used in the following situations:
- in case of long cables and low values of nominal resistance (such as PT100), at which the resistance and temperature-dependent resistance of the cable reach similar values
- for temperature sensors with low tolerance
- if significant electromagnetic interference is expected and twisted or protected cables are used

Change of resistance of thermal sensor PT100 in relation to temperature

PTC THERMAL SENSOR

PTC sensors are thermistors whose resistance is nonlinearly dependent on temperature. The sensors are manufactured with positive temperature resistance coefficient. Resistance-temperature relationship of the thermistor with positive temperature resistance coefficient is characterized by significant resistance increase when particular temperature is reached.

PTC thermistors are manufactured with response temperature (TNF) 80°С, 90°С, 100°С, 110°С, 120°С, 130°С, 140°С, 145°С, 150°С, 155°С, 160°С, 170°С. Other temperature range is to be clarified when placing an order.

Dependence diagram of PTC (TNF) sensor

Bimetallic thermal sensor

The principle of operation is based on the following: heating or cooling of the contacts between the conductors with different chemical and physical properties is accompanied with thermoelectric power (thermal emf). The thermal couple consists of two metals welded at one end. This part is placed in the area of temperature measurement. Bimetallic thermal sensor prevents motor overheating, ensuring its emergency switch-off when motor temperature reaches its highest value.