Thermocouples and Thermoresistances
8Pages

THERMOCOUPLES and THERMORESISTANCES Application: Temprature Measurement THERMOCOUPLES and THERMORESISTANCES Temprature measurement sensors for industrial use Figure 1: Standard Thermocouples Figure 2: Mineral Oxide Thermocouples Figure 3: Thermoresistances GENERAL CHARACTERISTICS Thermocouples (Figure 1 e 2) are components which are employed to measure the temperature. They consist of two metallic conductors, joint at one end (the so-called "junction") encapsulated into a metallic tube: if the temperature changes, the voltage that can be measured at the conductors terminals (= e.m.f., electro-motive-force) changes as well. This variation can be directly linked to the temperature that the junction is experiencing. Standard thermocouples have the junction which is in direct contact with the tube sheath (grounded-junction, see Figure 4). The metallic conductors within the tube are insulated by a fibreglass-silicon sheath. Mineral oxide thermocouples junction, on the contrary, is isolated from the tube sheath (see Figure 5). The metallic conductors are annealed into a compressed MgO powder. Also Thermoresistances are components which are employed to measure the temperature but, differently from thermocouples, the sensing element is a component, located at the end of the sensor, whose electrical resistance changes with changing temperature. This variation yields a measure of the temperature that the sensing element is experiencing. The standard construction for thermoresistances considers a 2-wires connection. For a better measurement accuracy, 3 or 4-wires connection are possible too (see Figure 6). Also for thermoresistances, both the standard (conductors insulation in fibreglass-silicone) and the mineral-oxide version (insulation made of MgO compressed powder) are possible. Figure 6: 9 9 9 9 ^Lyyyyu, 2-wires connection 3-wires connection Figure 4: grounded junction The junction of the sensing elements is made directly onto the tube sheath. Figure5: Isolated junction 4-wires connection The junction of the sensing elements is electrically and mechanically isolated from the sheath. This insures a long duration even if thermal shocks or corrosive conditions are experienced The thermocouples that Masterwatt supplies are compliant to ANSI or DIN specifications. The thermoresistances fulfil IEC or DIN requirements. ermocouples and Thermoresistanc

MSIBbAIT^_THERMOCOUPLES and THERMORESISTANCES Application: Temperature Measurement APPLICATIONS Standard Thermocouples (Figure 1) are suitable whenever severe operational conditions (i.e. vibrations, mechanical loads, pressure) are NOT present. Mineral Oxide Thermocouples (Figure 2) are recommended in all applications where a fast response or a reduced dimension of the sensing element I required. For this type of products it is also possible to manufacture double thermocouples (i.e. thermocouples with two sensing elements inserted into the tube sheath). Thermoresistances (Figure 3),...

/+S!E&AJT_THERMOCOUPLES and THERMORESISTANCES Application: Temprature Measurement MINERAL OXIDE INSULATION THERMOCOUPLES AND THERMORESISTANCES Code Sheath Material Sensing Element Hot Junction Max. temp. (°C) LE B c CD 2 O O 4 TCN 2759 AISI 304 Fe-CuNi isolated -10 / +700 0 230 1/4"G, 12MA, 12MB TRE 3753 -10 / +600 0 600 ermocouples and Thermoresistana

/+S!E&AJT_THERMOCOUPLES and THERMORESISTANCES Application: Temperature Measurement 300 _L = 2000_ ARMOURED FIBREGLASS-SIUCON CABLE -WR 12 B Pressure Connecter MINERAL OXIDE INSULATION THERMOCOUPLES AND THERMORESISTANCES Code TCN 2760 Sheath Material Sensing Element Hot Junction Isolated Max. temp. (°C) D B AISI 304 Fe-CuNi -10 / +700 2 1/4"G, 12MA, 12MB TRE 3754 1 PT 100 -10 / +600 2 LE L - 2000 j IIIIIIIIIIIIIIIIIIIHuuuuuuu_______(/-________1-U^^^" a s MINERAL OXIDE INSULATION THERMOCOUPLES Code Sheath Material Sensing Element Hot Junction Max. temp. (°C) D (mm) LE (mm) TCN 2710 AISI 304...

/+S!E&AJT_THERMOCOUPLES and THERMORESISTANCES Application: Temperature Measurement Code Sheath Material Max. temp (°C) Sensing Element D1 F mm D2 F mm Z mm EL TCN 2880 Pythag. DIN 610 750 Fe-CuNi 10 13 300 TCN 2890 Pythag. DIN 610 1200 Cr All 15 18 500 TRE 3800 Silim. DIN 530 1500 Pt Rh 10 % Pt 17 21 800 TRE 3805 Alsint 9.7 DIN 710 1500 Pt Rh 10 % Pt 26 30 1000 TCN 2895 Pythag. DIN 610 750 Fe-CuNi 10 17 21 300 TCN 2900 Pythag. DIN 610 1200 Cr All 10 17 21 500 TRE 3810 Silim. DIN 530 1500 Pt Rh 10 % Pt 16 26 30 800 TRE 3815 Alsint 9.7 DIN 710 1500 Pt Rh 10 % Pt 16 26 30 1000 TRE 3820 Alsint...

/MSFEfyffl_THERMOCOUPLES and THERMORESISTANCES Application: Temprature Measurement GENERAL CHARACTERISTICS Extension cables are used to prolong the standard length of the thermocouples cables so that they can be connected to the control panel even if it is located far away from the measurement point. They are manufactured using conductors with the same materials as those employed on the thermocouple that they have to be connected to. Thanks to this characteristic, they do not alter significantly the measurement value provided by the thermocouple. TECHNICAL DATA RELEVANT TO EXTENSION CABLES...

/+S!E&AJT_THERMOCOUPLES and THERMORESISTANCES Application: Temperature Measurement STANDARD CONNECTORS FOR THERMOCOUPLES 镕 12,4 Standard Single iH7 Tr ו 12,4 Standard Construction Characteristics Shell Material: Thermoplastic: operating temperatures: -100 °C - + 250 °C Studs Material : Same as thermocouple material with single and multiple connectors from 2.8 mm diameter to 6 mm diameter. Calibration: K, J, T, E Colour Code: as per ANSI specifications As for the extension cables, the thermocouple connectors are manufactured using the same material as the one employed on the thermocouple...