The fluidized product then passes between contact surfaces 2 following passage through a brief clearance between leftmost weir 13 and {HEAD ~ the leftmost edge} of {TAIL ~ contact surfaces} 2 
of
The fluidized product then passes between contact surfaces 2 following passage through a brief clearance between leftmost weir 13 and { HEAD ~ the leftmost edge } of { TAIL ~ contact surfaces } 2
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH