The apparatus has a hollow body , with {HEAD ~ an inflow} and an outflow for {TAIL ~ the fluid}  
for
The apparatus has a hollow body , with { HEAD ~ an inflow } and an outflow for { TAIL ~ the fluid }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH