Thermocouples

Sensitron Thermocouples and wells are designed for making available to the industry a complete range of thermocouples for measuring temperatures from 150°C to 1600°C and, are highly accurate and sensitive. These thermocouples are offered with a very wide range of thermowells of different materials to suit the application.
Basically, a thermocouple is composed of two dissimilar metal wires butt welded together in a circuit. The circuit develops a small EMF, in accordance with See back effect, between the measuring and reference junctions. This EMF can be measured by means of any pyrometer in terms of temperature. 
Sensitron Thermocouples are fabricated by gas or arc welding or resistance welding in accordance with ISA recommendations.
Special Thermocouple
The assembly consists of single or duplex thermocouple elements with cylindrical ceramic insulators encased in a spring loaded stainless tube. It is supplied with a screwed cover head and pipe nipple with 4 ¼' NPT mounting thread. In order to get highest speed of response to a temperature change, the last inch of the bore in the well is reduced in diameter to provide a tight fit around the sensitive tip of the thermocouple. 
The spring loaded feature ensures positive metal to metal contact between the thermocouple and well allowing the highest possible rate of heat transfer to the measuring junction. Spring padding also allows movements of the thermal element due to expansion and contraction without damage to the element or connecting head and terminal block.