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