Seal-bearing assembly
A seal-bearing assembly to be inserted into the seal cavity of a mechanical device to provide a seal and a bearing surface to eliminate whip in a rotating and/or reciprocal cylindrical member. The seal-bearing assembly is particularly well suited for use in a reciprocal pump or a piston-driven valve, or between the steam lance and fixed steam tube in a sootblower. The assembly includes at least a pair of outer substantially rigid cylindrical bearings having an inner bore to be positioned over the cylindrical member and at least one complimentary flexible textile packing ring substantially comprised of carbon disposed between the two outer bearing members. In assemblies including an additional bearing, the additional bearing is surrounded by at least one flexible packing on each side. The inner bore of the bearing members provides a bearing surface for eliminating whip of the moving elements in the device.
1. A seal-bearing assembly for a mechanical device having a shaft with reciprocating movement, comprising:
a first substantially rigid high performance polymeric cylindrical outer bearing;
a second substantially rigid high performance polymeric cylindrical outer bearing spaced apart from and axially aligned with the first outer bearing; and
a cylindrical textile packing member including carbon yarn adjacent to each of the first and second outer bearings,
wherein each cylindrical textile packing member is formed from a combination of at least 90 percent pure carbon fiber and carbon-inserted graphite exfoliated foil, providing a resilient carbon center around which the exfoliated carbon-inserted foil is braided with carbon yarn in the corners.
2. The seal-bearing assembly of claim 1 , wherein at least one of the first and second outer bearings comprises high-temperature polymeric material or a formulation thereof.
3. The seal-bearing assembly of claim 2 , wherein the first and second outer bearings each comprise a high-temperature polymeric material selected from the group consisting of polyphenylene sulfide, polyimidazoles, fluoropolymers, polyamide-imides, polyimides, polyether ketone polymers, and formulations thereof.
4. The seal-bearing assembly of claim 3 , wherein the first and second outer bearings each comprise polytetrafluoroethylene or a perfluoroalkoxy polymer.
5. The seal-bearing assembly of claim 3 , wherein the first and second outer bearings each comprise polybenzimidazole or a formulation thereof.
6. The seal-bearing assembly of claim 1 , wherein at least one of the first and second outer bearings includes an external O-ring.
7. The seal-bearing assembly of claim 1 , wherein the cylindrical textile packing members are formed from at least 90 percent pure carbon fiber.
8. The seal-bearing assembly of claim 1 , wherein the cylindrical textile packing material including the carbon yarn may also include yarn selected from the group consisting of graphitized yarns, exfoliated graphite yarns, ceramic yarns, and glass yarns.
9. The seal-bearing assembly of claim 1 , wherein the cylindrical textile packing members include a lubricant material.
10. The seal-bearing assembly of claim 1 , wherein at least one packing member acts as a wiper to trap any mechanical displacement of carbon or other media particles.
11. The seal-bearing assembly of claim 1 , wherein a third substantially rigid cylindrical bearing is positioned between the first and second outer bearings.
12. The seal-bearing assembly of claim 11 , wherein at least one cylindrical packing member is positioned between the third cylindrical bearing and each of the first and second outer bearings.
13. The seal-bearing assembly of claim 11 , wherein the third cylindrical bearing comprises a lantern ring.