Inside the collection chamber assembly the air is filtered, the chalk dust remaining in the collection chamber of the assembly, while {HEAD ~ filtered air} is exhausted by {TAIL ~ the suction device} 
is exhausted by
Inside the collection chamber assembly the air is filtered , the chalk dust remaining in the collection chamber of the assembly , while { HEAD ~ filtered air } is exhausted by { TAIL ~ the suction device }
OTH OTH OTH OTH 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 REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL