{HEAD ~ This movement} causes {TAIL ~ the compensating spool} to reduce the opening of one row of cross sectional holes and increase the opening of the other 
causes
{ HEAD ~ This movement } causes { TAIL ~ the compensating spool } to reduce the opening of one row of cross sectional holes and increase the opening of the other
HEAD HEAD HEAD HEAD HEAD HEAD REL 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