# US 10,871,255 B2 · Material for use in lining large-diameter pipes and a method of making same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,871,255 B2 - Document ID: US10871255B2 - Status: Granted - Kind: B2 - Application number: 16/346,474 - Filed: 2017-10-31 - Published: 2019-09-12 - Granted: 2020-12-22 - Earliest claimed: 2016-10-31 - Assignees: Scott & Fyfe Limited - Applicants: Scott & Fyfe Limited - Inventors: David Tough - Web page: https://patentgrep.com/patent/US10871255B2 ## CPC - F16L 55/1656: {materials for flexible liners} - B29C 63/26: Lining or sheathing of internal surfaces (B29C63/38 takes precedence) - B29C 63/30: using sheet or web-like material - B29C 70/28: Shaping operations therefor - D04B 21/16: incorporating synthetic threads - B29C 70/222: {the structure being shaped to form a three dimensional configuration} - B29C 70/56: Tensioning reinforcements before or during shaping - B29D 23/00: Producing tubular articles (B29D24/00 takes precedence) - D10B 2403/0112: One smooth surface, e.g. laminated or coated - D10B 2403/021: Lofty fabric with equidistantly spaced front and back plies, e.g. spacer fabrics - D10B 2505/02: Reinforcing materials; Prepregs - F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - D04B: KNITTING - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) - D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES ## Abstract A material for use in lining large-diameter pipes is disclosed. A textile material formed to a tubular shape and impregnated with resin may, on curing the resin, repair a damaged pipe in a cure in place pipe (CIPP) rehabilitation process. The present invention provides both a novel structure of tubular material and a novel method of preparing the material for use in a CIPP rehabilitation process, specifically aimed at large-diameter pipes such as oil rig caissons. The tubular material of this invention comprises four sheets of a double-bed warp-knitted fabric (40). A first pair of sheets (52) are arranged to form, respectively, inside and outside surfaces of a first half-tube, with fabric machine direction extending along the length of the half-tube. The second pair of sheets (52a) are similarly arranged to form a second half-tube. The two half-tubes are connected at a pair of longitudinally extending joins (58, 60). The preparation process includes stabilising tensioned sheets with a mesh layer (44), which makes for better handling of the knitted fabric. ## Claims ### Claim 1 A material for use in lining large-diameter pipes, the material comprising four sheets of a double-bed warp-knitted fabric having a machine direction and a cross direction, the sheets being arranged into a tubular structure with a first half of the tube comprising a first pair of fabric sheets, one forming an inside surface of the half-tube; and the other forming an outside surface; and a second half of the tube comprising a second pair of fabric sheets similarly aligned wherein the first and second halves of the tube are connected at a pair of longitudinally extending joins; and the four fabric sheets are aligned with the machine direction extending longitudinally along the tube. ### Claim 2 (depends on 1) A material according to claim 1 wherein each longitudinally extending join includes a sewn seam. ### Claim 3 (depends on 1) A material according claim 1 wherein the material comprises six sheets of a double-bed warp-knitted fabric and each half of the tube includes a third fabric sheet intermediate its pair of fabric sheets. ### Claim 4 (depends on 1) A material according to claim 1 wherein the pair of fabric sheets forming each half of the tube are offset relative to each other in a circumferential direction thereby forming an overlap part. ### Claim 5 (depends on 4) A material according to claim 4 wherein the offset is in the range 50-200 mm. ### Claim 6 (depends on 5) A material according to claim 5 wherein each overlap part is bonded to a layer of the other half of the tube. ### Claim 7 (depends on 6) A material according to claim 6 wherein the overlap parts extend over the sewn seam. ### Claim 8 (depends on 1) A material according to claim 1 wherein the material is knitted from a glass fibre yarn. ### Claim 9 (depends on 8) A material according to claim 8 wherein the material is knitted on a double-bed knitting machine in which two outer bars are arranged to produce a tricot knit on each respective bed and two inner bars are arranged to produce a tricot-type knit in which successive stitches are knitted on alternate beds of the knitting machine. ### Claim 10 (depends on 9) A material according to claim 9 wherein the tricot knit produced by said two outer bars is selected from a group comprising: 1-needle tricot, 2-needle tricot and 3-needle tricot. ### Claim 11 (depends on 10) A material according to claim 10 wherein a further two bars of the knitting machine are arranged to produce a second tricot knit on each respective bed. ### Claim 12 (depends on 11) A material according to claim 11 wherein the second tricot knit produced by said further two bars is selected from a group comprising: 1-needle tricot, 2-needle tricot and 3-needle tricot. ### Claim 13 (depends on 12) A material according to claim 12 wherein the tricot-type knit produced by the two inner bars comprises a tricot-type stitch on one needle bed and an open loop stitch on the other needle bed, wherein on each respective needle bed, successively-formed stitches are stepped two needle positions in a zigzag pattern. ### Claim 14 A method of preparing a liner material for installation in a large-diameter pipe, the method comprising the steps of: (a) Warp-knitting a pair of fabric sheets on a double needle-bed knitting machine; (b) Tensioning the fabric sheets in their machine direction; (c) Aligning the tensioned sheets and a stabilising mesh layer such that the mesh layer is intermediate the sheets; (d) Adhering the tensioned sheets and mesh together to produce a first mesh-stabilised web; (e) Repeating steps (a) to (d) to produce a second mesh-stabilised web; (f) Aligning the first and second mesh-stabilised webs to form a four-layer assembly; (g) Connecting the webs along longitudinal joins that extend parallel to the fabric machine direction, one join towards each edge of the assembly; (h) Tensioning the assembly; (i) Heating the assembly, thereby removing the integrity of the stabilising mesh; (j) Cooling the assembly; and (k) Removing the tension. ### Claim 15 (depends on 14) A method according to claim 14 wherein Step (a) is carried out using glass fibre. ### Claim 16 (depends on 15) A method according to claim 15 wherein the mesh-stabilised webs are connected together at Step (g) by sewing. ### Claim 17 (depends on 16) A method according to claim 16 wherein: in aligning the tensioned sheets and mesh in Step (c), the sheets are offset in a cross-direction with respect to each other to leave an overlap region on each sheet; in aligning the first and second mesh-stabilised webs to form a four-layer assembly at Step (f), one of the overlap regions from each web extends from each side; and after connecting the webs along longitudinal joins, the method includes the additional step of folding the overlap regions over the joins prior to heating the assembly at Step (i), whereby at this Step (i), the overlap regions are bonded over the joins. ### Claim 18 (depends on 17) A method according to claim 17 wherein in carrying out Step (a) two outer bars of the knitting machine produce a tricot knit on each respective bed and two inner bars produce a tricot-type knit in which successive stitches are knitted on alternate beds of the knitting machine. ### Claim 19 (depends on 18) A method according to claim 18 wherein a further two bars of the knitting machine produce a second tricot knit on each respective bed. ### Claim 20 (depends on 19) A method according to claim 19 wherein the tricot knit on the outer bars is selected from a group comprising: 1-needle tricot, 2-needle tricot and 3-needle tricot. ### Claim 21 (depends on 19) A method according to claim 19 wherein the second tricot knit is selected from a group comprising: 1-needle tricot, 2-needle tricot and 3-needle tricot. ### Claim 22 (depends on 15, 18) A method according to claim 18 wherein Step (a) includes warp-knitting a third fabric sheet and Steps (b) to (d) are carried out with the three fabric sheets and, if dependent on claim 15, the step of aligning three fabric sheets includes aligning them with respective offsets. ### Claim 23 (depends on 22) A method according to claim 22 wherein the method includes the additional step of infusing the assembly in a curable resin. ### Claim 24 (depends on 23) A method according to claim 23 which includes the additional steps of inserting the infused assembly into a caisson and curing.