The first valve is provided in {HEAD ~ the first connection passage} to open and close {TAIL ~ the first connection passage} 
to open
The first valve is provided in { HEAD ~ the first connection passage } to open and close { TAIL ~ the first connection passage }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL