To enable reopening, a bypass system connects the upstream side of {HEAD ~ metering valve} to {TAIL ~ the first chamber}, while there is a manually operated closure for manually opening and closing off the bypass to the first chamber 
to
To enable reopening , a bypass system connects the upstream side of { HEAD ~ metering valve } to { TAIL ~ the first chamber } , while there is a manually operated closure for manually opening and closing off the bypass to the first chamber
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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH