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