At the input and output of a material from the dryer 15 drum feeders 18 are installed, playing {HEAD ~ a role} not only as batch feeders, but also as {TAIL ~ gas sealers}, not permitting any external air intake 
At the input and output of a material from the dryer 15 drum feeders 18 are installed , playing { HEAD ~ a role } not only as batch feeders , but also as { TAIL ~ gas sealers } , not permitting any external air intake
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH