A brazing oven includes {TAIL ~ an arrangement} employing a gas curtain or {HEAD ~ barrier} to cover the port or opening of the oven whenever the door is opened 
A brazing oven includes { TAIL ~ an arrangement } employing a gas curtain or { HEAD ~ barrier } to cover the port or opening of the oven whenever the door is opened
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH