Seal assembly for ultrahigh-pressure vessels
A seal assembly is provided to seal a pressure vessel and an adjacent enclosure. A metal support ring configured to contact a first sealing surface and a second sealing surface when installed in a pressure vessel, is provided with a low friction coating with transferable low friction additives which results in the transfer of a solid lubricant film onto the vessel wall enclosure. Two polymer seals are provided adjacent the metal support ring and the pressure vessel and enclosure respectively, the polymer seals having a configuration and being formed of a high resilience material, to increase the longevity of the seal assembly.
1 . A seal assembly for a pressure vessel comprising:
a metal support ring configured to contact a first sealing surface and a second sealing surface when installed in a pressure vessel;
a low-friction coating provided on the metal support ring;
a first polymer seal positionable between the metal support ring and the first sealing surface; and
a second polymer seal positionable between the metal support ring and the second sealing surface.
2 . The seal assembly according to claim 1 wherein the low-friction coating has transferable low-friction characteristics.
3 . The seal assembly according to claim 1 wherein the low-friction coating includes an additive of low-friction particulates.
4 . The seal assembly according to claim 1 wherein the coating is a carbon-based coating.
5 . The seal assembly according to claim 1 wherein the coating is electroless nickel.
6 . The seal assembly according to claim 5 wherein the coating includes an additive selected from the group of PTFE, boron-nitrite, and graphite.
7 . The seal assembly according to claim 1 wherein the low-friction coating provided on the metal support ring results in a friction coefficient of less than about 0.1 against stainless steel.
8 . The seal assembly according to claim 1 wherein the metal support ring is made of a high-strength material having a low modulus of elasticity.
9 . The seal assembly according to claim 8 wherein the high-strength material has a modulus of elasticity less than about 19 million psi and a yield strength of about 80,000 psi-140,000 psi.
10 . The seal assembly according to claim 8 wherein the metal support ring has a hardness of less than RC38.
11 . The seal assembly according to claim 1 wherein the first polymer seal has a first annular edge and a second annular edge and a groove provided therebetween, the first and second annular edges being configured to seat against the first sealing surface when the first polymer seal is installed in a pressure vessel.
12 . The seal assembly according to claim 11 wherein the first polymer seal is made from a high-resilience polymer.
13 . The seal assembly according to claim 12 wherein the first polymer seal is made from urethane.
14 . A metal support ring for supporting a polymer seal to seal a pressure vessel comprising:
a body formed of a high-strength material having a low modulus of elasticity, the body having a first region to receive a first polymer seal and a second region to receive a second polymer seal; and
a low-friction coating provided on an external surface of the body.
15 . The metal support ring according to claim 14 wherein the low-friction coating includes an additive of low-friction particulates.
16 . The metal support ring according to claim 14 wherein the coating is a carbon-based coating.
17 . The metal support ring according to claim 14 wherein the coating is electroless nickel.
18 . The metal support ring according to claim 14 wherein the coating includes an additive selected from the group of PTFE, boron-nitrite, and graphite.
19 . A method for sealing a pressure vessel comprising:
positioning a metal support ring coated with a low-friction coating adjacent a first sealing surface and a second sealing surface; and
positioning a first polymer seal in a first region of the metal support ring adjacent the first sealing surface, the polymer seal being larger than the first region to precompress the first polymer seal.
20 . The method according to claim 19 , further comprising:
providing a quantity of lubricant between the first polymer seal and the first sealing surface.
21 . A pressure vessel comprising:
an annular wall forming a body of the pressure vessel;
a closure positionable adjacent the annular wall; and
a seal assembly coupled to the closure and to the annular wall, the seal assembly having a metal support ring adjacent the annular wall and the closure, a first polymer seal positioned between the metal support ring and the annular wall, and a second polymer seal positioned between the metal support ring and the closure, the metal support ring being coated with a low-friction coating.
22 . The pressure vessel according to claim 21 wherein the low-friction coating includes an additive of low-friction particulates.
23 . The pressure vessel according to claim 21 wherein the coating is a carbon-based coating.
24 . The pressure vessel according to claim 21 wherein the coating is electroless nickel.
25 . The pressure vessel according to claim 21 wherein the coating includes an additive selected from the group of PTFE, boron-nitrite, and graphite.
26 . The pressure vessel according to claim 21 wherein the first polymer seal has a first annular edge and a second annular edge and a groove provided therebetween, the first and second annular edges being configured to seat against the annular wall.