{HEAD ~ The pressure} for moving piston 40 and mandrel 38 upwardly to open the valve is supplied to {TAIL ~ cylinder} 42 below the piston through lateral opening 60 in the sidewall of lower housing section 12 
is supplied to
{ HEAD ~ The pressure } for moving piston 40 and mandrel 38 upwardly to open the valve is supplied to { TAIL ~ cylinder } 42 below the piston through lateral opening 60 in the sidewall of lower housing section 12
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH