wherein the diaphragm is generally circular, and the truncated surface being the surface that inter engages the diaphragm, the valve seat further comprising a surface of {HEAD ~ the dome} that slopes away from the truncated surface and is adapted to remain disengaged from {TAIL ~ any portion} of the diaphragm 
wherein the diaphragm is generally circular , and the truncated surface being the surface that inter engages the diaphragm , the valve seat further comprising a surface of { HEAD ~ the dome } that slopes away from the truncated surface and is adapted to remain disengaged from { TAIL ~ any portion } of the diaphragm
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH