At the declining ramp 20, i.e. downstream of threshold 18, there occurs {HEAD ~ a vertically directed suction flow} prompting {TAIL ~ the lateral gathering} of fibre fleece 4 into a fibre sliver 
prompting
At the declining ramp 20 , i.e. downstream of threshold 18 , there occurs { HEAD ~ a vertically directed suction flow } prompting { TAIL ~ the lateral gathering } of fibre fleece 4 into a fibre sliver
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH