Even though they work constantly in devices all around us, very few people understand different thermocouple types and their uses. Thermocouples, generally referred to by the shorter word TCs, are used in everyday items all over. It would be shocking to discover how odd our life would really be without them. They are used in things like water heaters and furnaces to our cars and trucks. With out them our life would be quite strange.
Generally the TC is a metal sensor used to find temperature or temperature differences. The basic principle is that as dissimilar metals are put together there is a generally proportional voltage that is produced between them. The voltage is immediately related to the different temperature of the metals the TC is comprised of. Using this principle, there are many different TCs depending on their intended use.
Type K is constructed from alumel and chromel. It is often used for the general use and all purpose units. It has a very low cost for its construction and can be found being used various kinds of probe sensors. Its sensitivity range is from -200 C to about +1200 degrees C.
Type E is constructed from constantan and chromel. Looking at the higher than average output they are generally only used for cold temperature applications. It is also used for non magnetic applications. Its counter is the type B made from constructed from rhodium and platinum. Because the output voltage curve is high they are used for temperatures ranging around 1800 degrees C.
Type N is constructed from nisil and nicrosil. It is notable for its higher stability and fantastic resistance for high temperature oxidation. Due to it not being made using platinum it has a production cost that is much lower and is often a unit of choice for most high temperature applications today. It was built as a replacement for all types K TCs and is used for everyday applications more and more.
Type S and type R are both built using platinum and rhodium. Because of the use of platinum they often have a very high production cost. Type R's are generally suited for high temperatures up to +1600 degrees C. Types S's are generally suited for high temperatures up to +1600 degrees as well. Type S's are commonalty used for production gold melting as gold's melting point is around 1064 degrees C.
Type J is made from iron and constantan. It has a very limited temperature range from -40 degrees C to +750 degrees C. Because of its limited operational range it is less popular than the more widely used type K. Its main use is with older vintage equipment that is not able to use more modern TCs.
This is a basic look at the more common of the thermocouple types and the things they are used for. Even though it seems their name makes them sound very complex or rare, nothing could possibly be further from the truth. When you take a nice hot shower just relax, your water heater's thermocouple has been working quietly to keep the water hot every hour of every day.
If you would like to know more about type k thermocouple parts take a look at this site. Additional information on STI Manufacturing can be found at http://www.stimfg.com today.