I have seen some very informative posts here in the elsmar forums regarding thermocouples and their verification.
I understand this is an old thread, but I figured this was the best place for my questions
We use ovens for some of our processes. The range in question is 100 - 250 deg F with a desired tolerance of +/- 10 deg F.
8 ovens temperatures are verified quarterly.
We use a Fluke 51 that is NIST calibrated yearly with k type thermocouples.
Ideally I would just purchase new thermocouples yearly and have them NIST calibrated, however I am part of a small company who is trying to keep costs down.
Again re-iterating acceptable range for the process is +/-10 deg F.
Would it be acceptable to do the following:
Purchase an Omega 5 pack of K type thermocouples (5SC-TT-K-30-36). Obtain a 3 point NIST cal on one of the 5 as they ??? typically calibrate one out of the pack of 5, which counts as a lot calibration.?
Question 1) Due to our infrequent use would it acceptable to keep a single thermocouple from the lot as a ?gold standard? which would be set off to the side and then only used when verifying yearly against one of the other thermocouples?
Question 2) Is it acceptable to use a concept of ?lot calibration? for thermocouples?
Question 3) if you have a ?gold standard? thermocouple that is sitting off to the side in ambient conditions, how long would you consider it be acceptable before having a NIST calibration performed again? (1 year, 2 year? )
Question 4)..... or would it be more preferable to not use the gold standard as is question 1, but instead to verify against crushed ice / boiling water as a verification of proper functioning?
Thank you for your time
Qu1nn
I understand this is an old thread, but I figured this was the best place for my questions
We use ovens for some of our processes. The range in question is 100 - 250 deg F with a desired tolerance of +/- 10 deg F.
8 ovens temperatures are verified quarterly.
We use a Fluke 51 that is NIST calibrated yearly with k type thermocouples.
Ideally I would just purchase new thermocouples yearly and have them NIST calibrated, however I am part of a small company who is trying to keep costs down.
Again re-iterating acceptable range for the process is +/-10 deg F.
Would it be acceptable to do the following:
Purchase an Omega 5 pack of K type thermocouples (5SC-TT-K-30-36). Obtain a 3 point NIST cal on one of the 5 as they ??? typically calibrate one out of the pack of 5, which counts as a lot calibration.?
Question 1) Due to our infrequent use would it acceptable to keep a single thermocouple from the lot as a ?gold standard? which would be set off to the side and then only used when verifying yearly against one of the other thermocouples?
Question 2) Is it acceptable to use a concept of ?lot calibration? for thermocouples?
Question 3) if you have a ?gold standard? thermocouple that is sitting off to the side in ambient conditions, how long would you consider it be acceptable before having a NIST calibration performed again? (1 year, 2 year? )
Question 4)..... or would it be more preferable to not use the gold standard as is question 1, but instead to verify against crushed ice / boiling water as a verification of proper functioning?
Thank you for your time
Qu1nn
I would suggest, though, that the wire on the roll has unlimited life until it is cut from the roll. Then it has a shelf life. However, given how little you are going to use, I wouldn't buy that much on a roll anyway.