{HEAD ~ at least one stage} of {TAIL ~ a first turbine impeller} for discharging the sucked gas in the axial direction, the first turbine impeller being affixed to a suction part side end face of the rotating shaft, and 
{ HEAD ~ at least one stage } of { TAIL ~ a first turbine impeller } for discharging the sucked gas in the axial direction , the first turbine impeller being affixed to a suction part side end face of the rotating shaft , and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH