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