The lower discharge surface is spaced apart from {HEAD ~ the upper discharge surface} by {TAIL ~ a distance} equal to D1 
by
The lower discharge surface is spaced apart from { HEAD ~ the upper discharge surface } by { TAIL ~ a distance } equal to D1
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH