Sealing Sleeve for Slip Joint

Abstract

A sleeve for sealing an annular gap between opposed co-axial surfaces of a slip joint includes a tubular body formed from a metallic material and having a first end, a second end, a center section between the first and second ends, and a longitudinal cross-sectional profile having a plurality of bendable curves. The sleeve is shaped so that two or more of the bendable curves contact each opposed coaxial surface to form two or more circumferential lines of contact with each opposed coaxial surface. The sleeve further includes a self-protective oxide undercoat layer that protects the metallic material and a lubricous overcoat layer that provides lubricity to the contact surfaces when the sleeve is exposed to temperatures greater than about 600° C.

What is claimed is: 
     
         1 . A sleeve for sealing an annular gap between opposed co-axial surfaces of a slip joint, the sleeve comprising:
 a tubular body formed from a metallic material and having a first end, a second end, a center section between the first and second ends, and a longitudinal cross-sectional profile having a plurality of bendable curves, with at last two bendable curves contacting each opposed coaxial surface to form at least two circumferential lines of contact with each opposed coaxial surface;   an undercoat layer comprising a self-protective oxide coating and covering substantially all of the surface area of the tubular body; and   an overcoat layer covering the undercoat layer at least about the lines of contact and configured to provide lubricity to the contact surfaces when the sleeve is exposed to temperatures greater than about 600° C.,   wherein a non-flexed distance between opposing circumferential lines of contact is between about 6% and about 14% greater than an average distance between the opposed coaxial surfaces, as measured perpendicular to a longitudinal axis of the tubular body.   
     
     
         2 . The sleeve of  claim 1 , wherein the plurality of bendable curves further comprise a first rolled end and a second rolled end, the first and second rolled ends forming inwardly opposing arcs, each having an arc length greater than or about 230 degrees to provide the circumferential lines of contact with each opposed coaxial surface. 
     
     
         3 . The sleeve of  claim 2 , wherein the center section is spaced from a nearest slip joint surface by at least about 10% of the average distance between the opposed coaxial surfaces upon installation of the sleeve into the annular gap. 
     
     
         4 . The sleeve of  claim 2 , wherein the non-flexed distance further comprises a non-flexed diameter of the arcs as measured between opposed contact surfaces. 
     
     
         5 . The sleeve of  claim 1 , wherein the plurality of bendable curves further comprise a plurality of alternating peaks together forming a wave-shaped profile within the center section. 
     
     
         6 . The sleeve of  claim 5 , wherein the non-flexed distance further comprises a non-flexed amplitude as measured between the outer contact surfaces of adjacent peaks. 
     
     
         7 . The sleeve of  claim 1 , wherein the metallic material is selected from the group consisting of a stainless steel alloy, an Inconel alloy, and a high-nickel alloy. 
     
     
         8 . The sleeve of  claim 1 , wherein the self-protective oxide coating is formed from a plurality of nanoparticles applied to the surface and heated to a first elevated temperature and for a predetermined period of time to form the self-protective oxide coating. 
     
     
         9 . The sleeve of  claim 8 , wherein the plurality of nanoparticles are selected from the group consisting of cerium oxide nanoparticles, titanium oxide nanoparticles, aluminum oxide nanoparticles, silicon oxide nanoparticles, scandium oxide nanoparticles, yttrium oxide nanoparticles, zirconium oxide nanoparticles, niobium oxide nanoparticles, hafnium oxide nanoparticles, tantalum oxide nanoparticles, and thorium oxide nanoparticles. 
     
     
         10 . The sleeve of  claim 1 , wherein the overcoat layer comprises boron nitride. 
     
     
         11 . The sleeve of  claim 1 , wherein the tubular body is seamless. 
     
     
         12 . A sleeve for sealing an annular gap between opposed co-axial surfaces of a slip joint, the sleeve comprising:
 a tubular body having a first rolled end, a second rolled end, and a center section between the first and second rolled ends;   the first and second rolled ends forming inwardly opposing arcs, each arc having an arc length greater than or about 230 degrees to form circumferential lines of contact with each opposed coaxial surface, and a diameter in a non-flexed condition that is at least about 10% greater than an average distance between the opposed coaxial surfaces; and   the center section being spaced from a nearest slip joint surface by at least about 10% of the average distance between the opposed coaxial surfaces upon installation of the sleeve into the annular gap.   
     
     
         13 . The sleeve of  claim 12 , wherein the tubular body further comprises:
 a substrate formed from a metallic material and having an upper surface and a lower surface;   an undercoat layer covering substantially all of the surface area of at least one of the upper surface and the lower surface, the undercoat layer comprising a self-protective oxide coating; and   an overcoat layer on the undercoat layer and configured to provide lubricity to the surface when the sleeve is exposed to temperatures greater than about 600° C.   
     
     
         14 . The sleeve of  claim 13 , wherein the metallic material is selected from the group consisting of a stainless steel alloy, an Inconel alloy, and a high-nickel alloy. 
     
     
         15 . The sleeve of  claim 13 , wherein the self-protective oxide coating is formed from a plurality of nanoparticles applied to the surface and heated to a first elevated temperature and for a predetermined period of time to form the self-protective oxide coating. 
     
     
         16 . The sleeve of  claim 13 , wherein the overcoat layer comprises boron nitride. 
     
     
         17 . A sleeve for sealing an annular gap between opposed co-axial surfaces of a slip joint, the sleeve comprising:
 a tubular body formed from a metallic material and having a first end, a second end, and a center section between the first and second ends, the center section including a bendable wave-shaped profile formed from a plurality of alternating peaks contacting the opposed co-axial surfaces, with at least two peaks contacting each opposed coaxial surface to form at least two circumferential lines of contact with each opposed coaxial surface;   an undercoat layer covering substantially all of the surface area of the tubular body, the undercoat layer comprising a self-protective oxide coating; and   an overcoat layer covering the undercoat layer at least on each of the peaks of the wave-shaped profile and configured to provide lubricity to the surface when the sleeve is exposed to temperatures greater than about 600° C.,   wherein a non-flexed amplitude as measured between the lines of contact of adjacent opposing peaks is at least about 10% greater than an average distance between the opposed coaxial surfaces.   
     
     
         18 . The sleeve of  claim 17 , wherein the metallic material is selected from the group consisting of a stainless steel alloy material, an Inconel alloy material, and a high-nickel alloy material. 
     
     
         19 . The sleeve of  claim 17 , wherein the self-protective oxide coating is formed from a plurality of nanoparticles applied to the surface and heated to a first elevated temperature and for a predetermined period of time to form the self-protective oxide coating. 
     
     
         20 . The sleeve of  claim 17 , wherein the overcoat layer comprises boron nitride.