{HEAD ~ The fluid product} flows through zone III while in thermal contact with the right half of contact surfaces 2, passes through {TAIL ~ a brief clearance} between the rightmost end of the contact surfaces 2 and the rightmost weir 13, over the upper edge of the rightmost weir 13 and eventually into collection conduit 16 provided at the bottom of zone IV 
passes through
{ HEAD ~ The fluid product } flows through zone III while in thermal contact with the right half of contact surfaces 2 , passes through { TAIL ~ a brief clearance } between the rightmost end of the contact surfaces 2 and the rightmost weir 13 , over the upper edge of the rightmost weir 13 and eventually into collection conduit 16 provided at the bottom of zone IV
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH