i have uses a piezometer-- a very simple one. in xerox machines, (specifically the 1048 copier, which made 2 sided copies) sheets that had been copied once tended to not lie flat, (they had a residual electrial charge) to correctly position and feed them for side 2, they were pulled into position by a vacuum motor.

you needed to be able to test and adjust if need, the vacuum, and used a piezometer to do so... it measured the air pressure! (to little, the paper tended to curl and feed crooked, to much, and it could jam)
hi musick and satin!


my other obsession