{HEAD ~ Vertical movement} of the plunger actuates a cam or {TAIL ~ screw} to vary the setting of the control element of the level control system 
actuates
{ HEAD ~ Vertical movement } of the plunger actuates a cam or { TAIL ~ screw } to vary the setting of the control element of the level control system
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH