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