Valve body and seal assembly
View Patent ↗A valve body and seal assembly comprises a valve body symmetrical about a longitudinal axis and comprising a circumferential seal retention groove and a frusto-conical valve body impact area for contacting a valve seat. An elastomeric seal is cast-in-place in the circumferential seal retention groove. Each seal comprises first and second seal sections in contact via an intra-seal interface, the interface simultaneously extending radially outward and longitudinally. First seal sections may comprise a first polyurethane having a higher modulus than a second polyurethane of which second seal sections may be comprised. First seal sections are cast and partially cured in a mold which is rotating about the longitudinal axis. Second seal sections are cast after the first seal sections are partially cured, resulting in the intra-seal interface shape described above. Cross-linking between first and second seal sections across the intra-seal interface is thus facilitated.
1. 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.
2. The valve body and seal assembly of claim 1 , wherein said first seal section first polyurethane is crosslinked with said second seal section second polyurethane.
3. The valve body and seal assembly of claim 1 , wherein said first seal section additionally comprises a cylindrical external surface portion.
4. The valve body and seal assembly of claim 1 , wherein said first seal section frusto-conical external surface portion is geometrically similar to said frusto-conical valve body impact area.
5. The valve body and seal assembly of claim 1 , wherein said first seal section comprises polyurethane of about 95 durometer Shore A hardness to about 60 durometer Shore D hardness.
6. The valve body and seal assembly of claim 5 , wherein said second seal section comprises polyurethane of about 75 to about 85 durometer Shore A hardness.
7. The valve body and seal assembly of claim 1 , wherein said second seal section comprises a substantially planar external surface portion.
8. The valve body and seal assembly of claim 1 , wherein said second seal section comprises a substantially non-planar external surface portion.
9. A valve comprising the valve body and seal assembly of claim 1 and a valve seat.
10. A valve comprising the valve body and seal assembly of claim 6 and a valve seat.