Instruction

When two dissimilar conductors are connected together to form a closed circuit and the two junctions are kept in different temperatures, thermal electromotive force (EMF) is generated in the circuit. When one end (Cold Junction) is kept constant at a certain temperature, normally at 0, and the other end (Measuring Junction) is exposed to unknown temperature, the temperature at latter end can be determined by measurement of EMF generated. This combination of two dissimilar conductors is called Thermocouple.

Applications

• Specially designed for control of electric circuits, alarm
• General and explosion proof type head available
• Wide selection ranges for protection tube material
• Stainless steel (304SS, 316SS, 310SS, 446SS, 347SS & 321SS)
• Inconel 600, Inconel 800
• Hastelloy-C, Hastelloy-B, Titanium, Monel, Tantalum and so on for Metallic
• Single and double element available

Features

• Quick reponse and stable temperature measurement by direct contact
• Wide range of temperature from -270 to 2,300°C
• Specifit spot or small space can be measured
• Rugged construction and easy installation

Insulators and protection tubes

Insulators

Thermocouples are widely used for temperature measurements of various gases and liquids. If bare thermoelement wires are exposed directly to detrimental atmospheres and fluid, affected resulting in reducing service life with severe deterioration and corrosion.
Thermcouples are, therefore, usually protected with insulators and protection tubes. In selection of suitable insulators and protection tubes, consideration should be given to the materials especially of heat resistance, mechanical strength, chemical stability, etc. depending in the respective operating conditions. This is the most important point in thermimetric pratice.

Caution : Due to high thermal conductivity of the metal bubes, minimum insertion length should be more than twenty five times of its overall diameter to eliminate heat coduction error.

Extension and compensation cables

It is theoretically ideal to have thermocouple connected directly to the instrument, long distance between them often makes the wiring cost prohibitive and causes some trouble in the measuring circuit, Therefore, it is desirable to use extension or compensating wires or cables that have same or similar EMF characteristics to those of thermocouples at ambient temperatures. It is also necessary to select insulation materials in accordance with the operating conditions.
HISCO have large stock of various wires and cables as listed below