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