{HEAD ~ a plurality} of {TAIL ~ air inlets} 32 at the lower periphery of the inner tube 30, and 
of
{ HEAD ~ a plurality } of { TAIL ~ air inlets } 32 at the lower periphery of the inner tube 30 , and
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH