Preferably, the compressor includes a delivery control mechanism responsive to pressure in the suction passageway to vary {HEAD ~ the effective cross sectional area} of {TAIL ~ the suction passageway} 
of
Preferably , the compressor includes a delivery control mechanism responsive to pressure in the suction passageway to vary { HEAD ~ the effective cross sectional area } of { TAIL ~ the suction passageway }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL