Kindly clarify what type of purging is advisable for pressure and DP tappings in air and fluegas lines of a process plant - continuous or intermittent? Any information/experience is most welcome.

 

Pressure and DP purging:
I never heard continuous purging being problem.
Do not take as gospel. In mining and metallurgy
so many of that type have been installed.
Low flow (say: 2 scfm )instrument air via constant flow rotameter.
Think of some precaution, ie: goose neck oriented up and tapped from a straightlenght of piping
that you can rod through. It should be there for life. Check how the burst of higher intermitent
purging fluid may affect the diaphragm of your XTR.