the hollow part has an opening that opens at an end face on {HEAD ~ a side} opposite {TAIL ~ the suction part side end face} of the rotating shaft, and 
opposite
the hollow part has an opening that opens at an end face on { HEAD ~ a side } opposite { TAIL ~ the suction part side end face } of the rotating shaft , and
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 TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH