What specification considerations need to be taken when you want to measure process vacuum readings (less than 10 mmHg / Torr absolute) when the process temperature exceeds 250 DegF. What if the process temperature exceeds 450 DegF?
Are there special fill fluids? Are there special mounting requirements? Are there metals that work better in these ranges (typically 316 sst is acceptable)?
What other considerations need to be taken?
Hi Robert,
The primary concern for high temperature / hard vacuum applications is to make sure that the internal oil fill of the pressure transmitter / remote seal assembly does not vaporize. In order for the pressure transmitter to remain functional, the oil fluid needs to remain in a liquid state. Operating a pressure transmitter in a vacuum state will lower the boiling point of a fill fluid.
Specifics on your questions:
Below is a link to a white paper you may find helpful on specifying and operating pressure technoloy under vacuum conditions.
http://www2.emersonprocess.com/siteadmincenter/PM%20Rosemount%20Documents/00840-0100-4016.pdf
Thanks,
Michael