For example in one embodiment, the valve seat is dome shaped with {HEAD ~ the top} of {TAIL ~ the dome} truncated or sliced off 
of
For example in one embodiment , the valve seat is dome shaped with { HEAD ~ the top } of { TAIL ~ the dome } truncated or sliced off
OTH 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 OTH OTH OTH OTH