When {HEAD ~ the pressure} in the second flow path reaches {TAIL ~ a predetermined value}, the second valve apparatus responds thereto by moving to an open configuration, thus permitting fluid communication along the second flow path 
When { HEAD ~ the pressure } in the second flow path reaches { TAIL ~ a predetermined value } , the second valve apparatus responds thereto by moving to an open configuration , thus permitting fluid communication along the second flow path
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH 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 OTH OTH OTH