{TAIL ~ Gas} can be introduced into {HEAD ~ the liquid} in any one or all of the chambers 
{ TAIL ~ Gas } can be introduced into { HEAD ~ the liquid } in any one or all of the chambers
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH