Some oxygen 24 passes through and {TAIL ~ some oxygen} and xenon and krypton are adsorbed and recovered during {HEAD ~ bed regeneration} 
Some oxygen 24 passes through and { TAIL ~ some oxygen } and xenon and krypton are adsorbed and recovered during { HEAD ~ bed regeneration }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD