{HEAD ~ The edge} of the partial ball is characterized by having {TAIL ~ a v notch} to obtain desired valve characteristics as well as to provide shearing actions at the sharp edges of the valve as it closes 
is characterized by having
{ HEAD ~ The edge } of the partial ball is characterized by having { TAIL ~ a v notch } to obtain desired valve characteristics as well as to provide shearing actions at the sharp edges of the valve as it closes
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH