The corrugation 22, concave arc portion 32 and horizontal flat portion 24 are located sequentially along {HEAD ~ the axis} of {TAIL ~ pipe} 20 
of
The corrugation 22 , concave arc portion 32 and horizontal flat portion 24 are located sequentially along { HEAD ~ the axis } of { TAIL ~ pipe } 20
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH