Re opening of the main valve is accomplished with {HEAD ~ the aid} of a bypass system connecting the upstream side of {TAIL ~ the metering valve} to the main valves first chamber 
Re opening of the main valve is accomplished with { HEAD ~ the aid } of a bypass system connecting the upstream side of { TAIL ~ the metering valve } to the main valves first chamber
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH