Patent ID: 8141849

Claim:
A valve body and seal assembly having a longitudinal axis, said valve body and seal assembly comprising: a valve body substantially symmetrical about said longitudinal axis, said valve body comprising a circumferential seal retention groove and a frusto-conical valve body impact area for contacting a valve seat; and an elastomeric seal cast-in-place in said circumferential seal retention groove, said elastomeric seal comprising: a first seal section substantially symmetrical about said longitudinal axis and having a frusto-conical external surface portion for contacting a valve seat, said first seal section comprising a first polyurethane; and a second seal section substantially symmetrical about said longitudinal axis and contacting said first seal section via a substantially smooth intra-seal interface, at least a portion of said second seal section lying between a portion of said circumferential seal retention groove and at least a portion of said first seal section, said second seal section comprising a second polyurethane having a lower modulus than said first polyurethane; wherein said intra-seal interface simultaneously extends radially outward and longitudinally.