Time to stir things up a bit!
I'm looking into a mercury thermometer from Cole Parmer.
The purpose is to calibrate my temp probes, but firstly the temp readings on my chiller. I want to get as close to 25 deg C as possible, as the coolant test temp.
Link to thermometer:
http://www.coleparmer.com/catalog/pr...=1&sel=0800130
That thermometer has a range of 19 deg C to 27 deg C, and is accurate to +/- 0.1 deg C. (ASTM# 17C)
The thing is, I don't know if the "ASTM method" is relevant: in this case, it's "Saybolt viscosity". Does anyone know?
The other problem I have is that this thermometer appears to be meant to be used "fully submerged". Although Cole Parmer provides a tutorial on how to compensate (calculated) for that, as far as I can tell, if I used it only partly submerged, I would be throwing off the accuracy of a reading by a maximum of 0.002 deg C. Is this of importance?
My third question would be: do I really need to get the NIST certificate (yearly?), and why?
Lastly, could I actually use this thermometer to measure a temp, while the pump is running, or would it be preferable to briefly stop the pump for a reading?