{HEAD ~ One end} of the tube 44 is in communication with a central portion of the tube 45, and the other end of the tube 44 is formed with {TAIL ~ a gas supply hole} 41 
{ HEAD ~ One end } of the tube 44 is in communication with a central portion of the tube 45 , and the other end of the tube 44 is formed with { TAIL ~ a gas supply hole } 41
HEAD HEAD HEAD HEAD HEAD HEAD 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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH