{HEAD ~ The rear part} or portion 24 of {TAIL ~ the chamber} 2, i.e. the part closest to the outlet end 18, is partly separated from the remaining part of the chamber by an annular partitioning 25 
{ HEAD ~ The rear part } or portion 24 of { TAIL ~ the chamber } 2 , i.e. the part closest to the outlet end 18 , is partly separated from the remaining part of the chamber by an annular partitioning 25
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL 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