{TAIL ~ The vent hole} is closed by the base plate of the fixed scroll member for {HEAD ~ the majority} of its operational cycle 
{ TAIL ~ The vent hole } is closed by the base plate of the fixed scroll member for { HEAD ~ the majority } of its operational cycle
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH