A slidable sleeve slides along the hollow body to close the orifices, causing the plunger to rise and carry {TAIL ~ accumulated fluid} to {HEAD ~ the well surface} 
A slidable sleeve slides along the hollow body to close the orifices , causing the plunger to rise and carry { TAIL ~ accumulated fluid } to { HEAD ~ the well surface }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD