In {HEAD ~ the absence} of {TAIL ~ an open configuration} of the second valve apparatus, fluid pressure increases in the second flow path 
of
In { HEAD ~ the absence } of { TAIL ~ an open configuration } of the second valve apparatus , fluid pressure increases in the second flow path
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