hello list,

Pl let me know what are the differences between the chromel alumel (K type) and Nicrosil nisil
(N type) thermocouples. I don't exactly see much difference between these two. Even then k type
is widely used when compared to N type. Does any one has justifying points to use N type in place
of K type.

Vijay

 

Vijay:
I know a little about N type thermocouple. Comparing with K type thermocouple, the material N type thermocouple is made of is similar and thus
it's as cheap as K type. But one of N type thermocouple's advantage is that the high limit of its measuring range is higher than that of K type. Normally, the measuring range of K type is 600-1200C.degree, but in condition of 1200C. degree, K type can't stand for a long time. Otherwise,it shall be damaged. According to my experience, this period should not be longer than two hours. For N type thermocouple, the high limit can be 1300 to 1350,and it can work well in
condition of 1200-1250C. degree continuously. So I have experience in using N type to substitute S type in application of Heating Furnace in rolling
mill. That's all for you reference.

 

Check out the Omega website. They have a reference section on thermocouples
at: "http://www.omega.com/temperature/Z/zsection.asp":http://www.omega.com/temperature/Z/zsection.asp

It even includes an article on N type thermocouples.

Matt Warshawsky
www.azeotech.com