In {TAIL ~ this embodiment}, {HEAD ~ the generally flat truncated surface} of the dome shaped valve seat is the diaphragm engaging surface 
In { TAIL ~ this embodiment } , { HEAD ~ the generally flat truncated surface } of the dome shaped valve seat is the diaphragm engaging surface
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH