a driving shaft extending through said vessel and inside {HEAD ~ said portion} of {TAIL ~ the sleeve element}, 
a driving shaft extending through said vessel and inside { HEAD ~ said portion } of { TAIL ~ the sleeve element } ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH