a pair of flow systems, {HEAD ~ each said flow system} being disposed for {TAIL ~ a flow} of fluid there through 
disposed for
a pair of flow systems , { HEAD ~ each said flow system } being disposed for { TAIL ~ a flow } of fluid there through
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH