Ash in pressurised oil system?
I have to admit, it is pretty counterintuitive that any one atmosphere contaminant can get into a pressurised lubrication system. What is the average sort of pressure in an aeroplane engine (high bypass fan jet)? A modern car is between 60 and 100 psi.
Having said that, I am an MRI engineer and our magnet cryogen recombinant systems work at about 4 psi. Given that Helium is the second smallest atom in the periodic table, it can leak through pretty much anything - outwards. However, magnets have personalities and some of them have an amazing propensity to suck atmospheric pressure air into them.
How do we know its there? Because various electrical ports that we need to use from time to time, become blocked with ice, but don't go thinking its just plain old frozen water. Oh dear me no. The water vapour freezes out long before it gets very far into the magnet. No, the ice we are talking about is where air (per se) has somehow got past 'O' rings into a 4 psi over ambient environment and the oxygen has condensed out, dripped about a foot deeper into the magnet and hit a metal surface somewhere where it freezes solid. Ever seen frozen oxygen? Its blue.
Can anyone actually explain how any ambient pressure contaminant can get into otherwise sealed, pressurised systems?
Roger.