{HEAD ~ The invention} 11 wherein {TAIL ~ said wall member} has an elongated opening, and wherein said gas flow inlet extends through said elongated opening 
{ HEAD ~ The invention } 11 wherein { TAIL ~ said wall member } has an elongated opening , and wherein said gas flow inlet extends through said elongated opening
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH