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