{HEAD ~ Oxygen} is also flowed into {TAIL ~ the tube} through a pair of oxygen injectors 
is flowed into
{ HEAD ~ Oxygen } is also flowed into { TAIL ~ the tube } through a pair of oxygen injectors
HEAD HEAD HEAD HEAD HEAD REL OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH