Preferably, however, {HEAD ~ the chamber} is slightly leaky in {TAIL ~ both directions} so that a pressure barrier, which builds up within the kiln as it generates reducing gases, prevents an oxidizing atmosphere from entering the kiln chamber or rapid atmosphere exchange 
Preferably , however , { HEAD ~ the chamber } is slightly leaky in { TAIL ~ both directions } so that a pressure barrier , which builds up within the kiln as it generates reducing gases , prevents an oxidizing atmosphere from entering the kiln chamber or rapid atmosphere exchange
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL 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 OTH OTH OTH OTH