The arcuate shape of the trough bottom results in an effect similar to an airfoil effect, whereby {HEAD ~ the aspirated air} is accelerated with the consequent beneficial effect on the gathering of the fibre fleece to the shape of {TAIL ~ a fibre sliver} 
The arcuate shape of the trough bottom results in an effect similar to an airfoil effect , whereby { HEAD ~ the aspirated air } is accelerated with the consequent beneficial effect on the gathering of the fibre fleece to the shape of { TAIL ~ a fibre sliver }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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