WO2001004531A1 - Conduit flexible et procede de fabrication correspondant - Google Patents

Conduit flexible et procede de fabrication correspondant Download PDF

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Publication number
WO2001004531A1
WO2001004531A1 PCT/US2000/018554 US0018554W WO0104531A1 WO 2001004531 A1 WO2001004531 A1 WO 2001004531A1 US 0018554 W US0018554 W US 0018554W WO 0104531 A1 WO0104531 A1 WO 0104531A1
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WO
WIPO (PCT)
Prior art keywords
coil
perfluoroplastic
tube
helical coil
flexible duct
Prior art date
Application number
PCT/US2000/018554
Other languages
English (en)
Inventor
Stephen W. Tippett
Original Assignee
Textiles Coated Incorporated
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Textiles Coated Incorporated filed Critical Textiles Coated Incorporated
Priority to AU59189/00A priority Critical patent/AU5918900A/en
Publication of WO2001004531A1 publication Critical patent/WO2001004531A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B1/00—Layered products having a non-planar shape
    • B32B1/08—Tubular products
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • B32B27/322—Layered products comprising a layer of synthetic resin comprising polyolefins comprising halogenated polyolefins, e.g. PTFE
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L11/00—Hoses, i.e. flexible pipes
    • F16L11/04—Hoses, i.e. flexible pipes made of rubber or flexible plastics
    • F16L11/11—Hoses, i.e. flexible pipes made of rubber or flexible plastics with corrugated wall
    • F16L11/112—Hoses, i.e. flexible pipes made of rubber or flexible plastics with corrugated wall having reinforcements embedded in the wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/70—Other properties
    • B32B2307/714—Inert, i.e. inert to chemical degradation, corrosion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2323/00—Polyalkenes
    • B32B2323/04—Polyethylene
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2597/00—Tubular articles, e.g. hoses, pipes

Definitions

  • This invention relates generally to flexible ducts of the type employed to convey various fluids, including gases and/or liquids, which may or may not be corrosive, under varying pressure and temperature conditions.
  • Ducts of this type are typically manufactured by one of two methods.
  • One existing commercial method involves literally clamping or crimping relatively narrow fabric strips in a helical pattern around a metallic reinforcement. Because this is strictly a mechanical joinder, only materials that can tolerate the stress of the mechanical clamping or crimping can be used in the process.
  • Other drawbacks include leakage that inevitably occurs between the crimped fabric strips, and damage of the metallic reinforcement when the ducts are exposed to corrosive environments.
  • the other method involves encapsulating the metal coils between the duct fabric and an additional strip, often of the same fabric.
  • the encapsulation is achieved via a chemical bonding or heat bonding of the two fabric materials, for example a PVC coated polyester fabric with a PVC film.
  • An objective of the present invention is the provision of an improved flexible duct fabricated from the preferred but difficult to heat seal or bond perfluoroplastics, by a novel thermal bonding method which avoids all of the drawbacks of conventional crimping methods.
  • a resilient helical coil is captured between inner and outer tubes formed of a perfluoroplastic material.
  • the tubes are thermally laminated or heat sealed together at locations other than those occupied by the helical coil by means of a melt bondable adhesive interposed between the helical coil and one of the tubes.
  • the resultant duct is both flexible and nonporous.
  • the resilient helical coil is completely encapsulated between the inner and outer tubes.
  • the inner tube is securely bonded to the outer tube, thus enabling the duct to operate reliably under negative as well as positive pressure conditions, and at elevated temperatures.
  • the duct is corrosion resistant and nonflammable. By selecting a dielectric perfluoroplastic material for the helical coil, the entire duct becomes electrically non conductive.
  • Figure 2 is an exploded perspective view of some of the major components of the flexible duct
  • Figure 3 is an enlarged partial sectional view taken along line 3-3 of Figure 1 ;
  • Figures 4A-4E are diagrammatic depictions of various stages during the fabrication of the flexible duct
  • FIGS 5A and 5B diagrammatically depict stages in the formation of the tube components
  • Figures 6A-6C depict various cross sections for extruded PTFE rods useful in forming helical coils
  • a flexible duct in accordance with the present invention is generally depicted at 10.
  • the duct 10 includes as basic components a corrosion barrier inner tube 12, a flexible and resilient helical coil 14, an outer tube 16, and a melt bondable adhesive 18 (shown only in Figure 3) interposed between the tubes 12, 16 and, where the coil is present, between the coil and one of the tubes, for example and as illustrated, between the coil and the inner tube.
  • the inner and outer tubes 12, 16 are formed from perfluoroplastic materials which may comprise: a) films of PTFE in skived, cast or extruded and oriented form; blends of PTFE and fluoroelastomers; blends of polyimide and PTFE; TFM, a modified form of PTFE supplied by Dyncon, LLC of Aston, Pennsylvania; b) Laminates of PTFE films, preferably extruded and oriented, in expanded or unexpanded form, including LFP; c) Composites, e.g., woven fabrics or textiles coated or surface laminated with FEP, PFA, PTFE; blends of perfluoroplastics and fluoroelastomers; and blends of polyimide and PTFE.
  • the woven fabrics or textiles may consist of fiberglass, amorphous silica, graphite, polyaramides, polybenzimadazole, ceramics, metal wires and combinations thereof.
  • Materials may be in either the sintered or unsintered form. Unsintered materials will become sintered during the fabrication process. Of the above materials, LFP is preferred.
  • the helical coil 14 may be fabricated from spring tempered carbon steel, stainless steel or other steel alloys.
  • the coil may be formed from a nonmetallic dielectric material, preferably sintered PTFE or LFP.
  • a coil formed from an extruded PTFE rod it may be advantageous to provide a cross section with one or more flat surfaces.
  • the rod may be extruded with a rectangular cross section (Fig. 6A), a square cross section (Fig. 6B), or with only two opposed flat surfaces (Fig. 6C).
  • the melt bondable adhesive 18 may comprise PFA, FEP or unsintered PTFE.
  • the method of producing a length of flexible duct in accordance with the present invention will now be described with reference to Figures 4A-4E.
  • a pressure core 20 is provided.
  • the pressure core will typically consist of a round lightweight metal duct wrapped with high temperature insulation fabrics.
  • the pressure core can consist of rolled pieces of insulation materials or fabrics.
  • the insulation fabrics can consist of woven and nonwoven materials, including fiberglass, amorphous silica, graphite, polyaramides, polybenzimadazole, ceramics and combinations thereof.
  • the interior metal duct of the pressure core collapses to ease its removal from the completed flexible duct.
  • the pressure core may also comprise a pneumatic assembly, or other mechanical systems designed to provide a radially adjustable internal member.
  • the pressure core 20 is initially surrounded by the corrosion barrier inner tube 12.
  • the tube 12 can either be preformed before being axially inserted over the pressure core, or it can be formed in situ on the pressure core.
  • the term "in situ" is intended to described formation of a duct component during rather than separately from formation of the entire duct assembly.
  • the tube 12 is formed from a rectangular sheet 22 of perfluoroplastic material having side edges 22a, 22b and end edges 22c, 22d.
  • a strip 24 of a melt bondable adhesive material, e.g., PFA is applied along edge 22a, and the sheet is then formed into a cylinder, with edge 22a overlapping edge 22b, and with the PFA strip 24 located between the overlapped edges.
  • Heat is then applied to heat seal the overlapped edges to produce a seam.
  • the seam can be produced by applying a heated sealing iron to the overlapping edges.
  • heat sealing can take place when the entire tube assembly is heated, as will be explained more fully hereinafter.
  • the inner tube 12 may be covered with the melt bondable adhesive 18, either by a coating process applied to the sheet material 22 prior to formation of the tube, or by wrapping a thin film of melt bondable material around the tube 12 after it has been positioned on the pressure core.
  • the helical coil 14 is then mounted on the pressure core 20 over the adhesive covering on the corrosion barrier inner tube 12.
  • the coil can be preformed and axially inserted in place, or it can be formed by helically wrapping a wire or the like around the inner tube 12.
  • the coil 14 is surrounded by the outer tube 16, which also can either be preformed, or formed in situ, in the same manner as described previously in connection with the formation and application of the inner tube 12.
  • the same covering can be applied to the interior surface of the outer tube 16.
  • the adhesive is ultimately positioned between the inner and outer tubes in all locations except those occupied by the coil. Where the coil is present, the adhesive is located between one of the tubes and the coil.
  • a high temperature ribbon 26 is then helically wrapped around the assembly to cover the areas between the mutually spaced turns of the coil 14.
  • the tubes 12, 16 are compressed between the wound ribbon 26 and the pressure core 20 into intimate contact with the melt bondable adhesive 18 interposed therebetween.
  • the tightly wound ribbon also assists in maintaining the spacing between the turns of the coil.
  • the ribbon may comprise any suitable high temperature material, including for example fiberglass lightly coated with PTFE.
  • the entire package is then placed in a high temperature environment for a period of time necessary to melt the melt bondable adhesive 18.
  • the package will be held in an oven heated to about 700 °F for a residence time of about fifteen minutes.
  • the package is then allowed to cool while the components of the duct assembly remain in a radially compressed state, i.e. , with both the pressure core 20 and outer helically wound tape 26 in place.
  • a radially compressed state i.e. , with both the pressure core 20 and outer helically wound tape 26 in place.
  • the outer helically wound tape 26 is unwound and removed from the outer tube, and the mandrel is extracted axially from the inner tube.
  • the resilient duct is then compressed axially to induce wrinkling as at 28 (see Figures 1 and 3) between the turns of the coil 14. This reduces the overall length of the duct while imparting flexibility to the finished product.
  • the corrosion barrier inner tube was produced using a Vi " overlap heat sealed splice with a 0.005" PFA film (500LP; E. I. Dupont, Wilmington, DE) serving as the melt bondable adhesive.
  • the inner tube was formed with a 3" ID and a 12" length.
  • a one mil (0.001 ") PFA film was thermally tacked to the exterior surface of the corrosion barrier inner tube.
  • the outer tube was also produced using a Vi " overlap heat sealed splice with 0.005" PFA film as the melt adhesive.
  • the tube was formed with a 3-1/4" ID and a 12" length.
  • the internal pressure core was manufactured using W needled fiberglass insulation mat (9 lb/cu ft density, BGF Industries, Inc. , Greensboro, NC). The mat was rolled into a log with a 3" ID and a 12" length.
  • the corrosion barrier inner tube was slipped over the internal pressure core.
  • the wire coil was then slipped over the corrosion barrier inner tube.
  • the outer cover tube was pulled over the entire assembly.
  • the assembly was wrapped tightly with a lightly coated PTFE fiberglass fabric (Style 7544 fabric, 18 oz/sq yd, BGF Industries, Inc., Greensboro, NC).
  • the coating weight of PTFE on the fabric was 2-3 oz/sq yd (ALGOFLON D60G PTFE dispersion, Ausimont USA, Thorofare, NJ).
  • the fabric wrap was held in place by strips of lightweight fiberglass fabric that were tied around the fabric wrap.
  • the entire package was placed in a 700 °F convection hot air oven for 15 minutes.
  • the package was suspended by metal rods at each end to ensure uniform heating throughout the package. At the conclusion of the heating step, the package was removed from the oven and allowed to cool to room temperature. Thereafter, the fabric wrap and internal pressure core were removed. The flexible duct was then compressed axially to form wrinkles between the coil turns. When the wrinkles were formed, the length of the duct reduced from 12" to approximately 10" in length.
  • the flexible duct possessed some stiffness but could be readily flexed without much effort.
  • the wire coil was manufactured using #14 tempered spring steel (0.063"), with a 3" ID, a 3 A " distance between turns, and a length of 12".
  • the corrosion barrier inner tube was produced using a Vi " overlap heat sealed splice and 0.005" PFA film (500LP; E. I. Dupont, Wilmington, DE) as the melt bondable adhesive.
  • the tube was formed with a 3" ID and a 12" length.
  • a light MFA coating was applied to the exterior surface of the corrosion barrier inner tube (Hyflon MFA; Ausimont USA; Thorofare, NJ).
  • the outer tube was also produced using a Vi " overlap heat sealed splice with 0.005" PFA film as the melt adhesive.
  • the outer tube was formed with a 3-1/4" ID and a 12" length.
  • the internal pressure core was manufactured using a combination of W needled fiberglass insulation mat and woven fiberglass fabric (Zetex 2200, 60 oz/sq yd, Newtex Industries, Victor, NY). The mat was rolled into a log with a 2-3/4" ID. The fiberglass fabric was wrapped around the insulation mat log, bringing the diameter of the internal pressure core to 3 " .
  • the corrosion barrier inner tube was slipped over the internal pressure core.
  • the wire coil was then slipped over the corrosion barrier tube.
  • the outer cover tube was pulled over the entire assembly.
  • the assembly was wrapped tightly in lightly coated PTFE fiberglass fabric strips that were Vi " wide (Style 7544 fabric, 18 oz/sq yd, BGF Industries, Inc. , Greensboro, NC).
  • the coating weight of PTFE on the fabric strips was 2-3 oz/sq yd (ALGOFLON D60G PTFE dispersion, Ausimont USA, Thorofare, NJ).
  • the fabric strips were wrapped between the coil turns, providing maximum lamination pressure for bonding the two tubes together.
  • the fabric strips also assisted in maintaining uniform spacing for the coil turns.
  • the entire package was placed in a 700 °F convection hot air oven for 15 minutes. The package was suspended by metal rods on each end to ensure uniform heating throughout the package.
  • the package was removed from the oven and allowed to cool to room temperature, after which the fabric wrap and internal pressure core were removed.
  • the flexible duct was compressed axially to form wrinkles between the coil turns. When the wrinkles were formed, the length of the duct reduced from 12" to approximately 11" in length.
  • Example #3 A 4-1/4" ID flexible duct, 20" long, was manufactured with both the inner corrosion barrier tube and the outer tube manufactured from LFP 2109. The inner tube color was black. The outer tube color was blue. The wire coil was manufactured using #14 tempered spring steel (0.063"), with a 4-1/4" ID, with a 1-1/4" distance between coil turns, and a length of 22".
  • the interior corrosion barrier tube was produced using a Vi " overlap heat sealed splice and 0.005" PFA film as the melt bondable adhesive.
  • the tube was manufactured with a 4-1/4" ID and a 22" length.
  • One-half mil (0.0005") PFA film was thermally tacked to the exterior surface of the corrosion barrier tube.
  • the outer tube was not preformed. Instead, it consisted of an LFP 2109 sheet,
  • the internal pressure core was manufactured using a 3" ID metal sleeve and woven fiberglass fabric (Zetex 2200, 60 oz/sq yd, Newtex Industries, Victor, NY). The fiberglass fabric was wrapped around the metal sleeve, bringing the diameter of the internal pressure core to 4-1/4".
  • the corrosion barrier inner tube was slipped over the internal pressure core.
  • the coil was then slipped over the corrosion barrier tube.
  • the outer cover sheet was wrapped around the entire assembly so that the PFA tacked along the edge overlapped and faced inwardly to cover the opposite edge of the outer cover sheet. In this manner, the outer tube is formed in situ during the subsequent heating.
  • the assembly was wrapped tightly in 3 A " wide lightly coated PTFE fiberglass fabric strips. The coating weight of PTFE on the fabric strips was 2-3 oz/sq yd. The fabric strips were wrapped between the coil turns, providing maximum lamination pressure for bonding the two tubes together.
  • the entire package was placed in a 700 °F convection hot air oven for 15 minutes. The package was suspended by metal rods on each end to ensure uniform heating throughout the package.
  • the package was removed from the oven and allowed to cool to room temperature, after which the fabric wrap and internal pressure core were removed.
  • the flexible duct was compressed axially to form wrinkles between the coil turns.
  • the length of the duct reduced from 22" to approximately 20" in length.
  • An inspection of the flexible duct revealed that adhesion had developed very uniformly between the inner and outer tubes at locations other than those occupied by the helical coil.
  • the two tubes were bonded well in the vicinity around the coil.
  • the 1-1/4" distance between the coils reduced slightly.
  • the outer cover was produced in situ, far fewer wrinkles were observed in the exterior cover.
  • the duct showed very good flexibility.
  • the wire coil was manufactured using #14 tempered spring steel (0.063"), with a 6" ID coil, a 1-1/2" distance between coil turns, and a coil length of 13".
  • the corrosion barrier inner tube was produced using a V2 " overlap heat sealed splice and 0.005" PFA film as the melt bondable adhesive.
  • the tube was manufactured with a 6" ID and a 13" length.
  • One-half mil (0.0005") PFA film was thermally tacked to the exterior surface of the corrosion barrier tube.
  • the outer tube was formed in situ from an LFP 2109 sheet, 13" x 20" .
  • Five mil (0.005") PFA film was thermally tacked along one of the 13" long edges.
  • the internal pressure core was manufactured using a 5" ID metal sleeve and woven fiberglass fabric (Zetex 2200, 60 oz/sq yd, Newtex Industries, Victor, NY). The fiberglass fabric was wrapped around the metal sleeve, bringing the diameter of the internal pressure core to 6".
  • the corrosion barrier inner tube was slipped over the internal pressure core.
  • the wire coil was then slipped over the corrosion barrier tube.
  • the exterior outer cover LFP 2109 sheet was wrapped around the entire assembly so that the PFA tacked along the edge overlapped and faced against the opposite edge region of the sheet.
  • the wrap material consisted of LFP 2109 and 0.005" PFA film.
  • the LFP material was slit into a Vi " strip. PFA of the same width was then thermally tacked to one side of the
  • the V2 " wide strip was wrapped over the coil for the length of the duct, forming a thicker build of product on the coil for wear or abrasion protection.
  • the assembly was wrapped tightly in lightly coated PTFE fiberglass fabric strips that were 1-1/4" " wide.
  • the coating weight of PTFE on the fabric strips was 2-3 oz/sq yd.
  • the fabric strips were wrapped in between the coil turns, providing maximum lamination pressure for bonding the two tubes together.
  • the entire package was placed in a 700 °F convection hot air oven for 15 minutes. The package is suspended by metal rods at each end to ensure uniform heating throughout the package.
  • the package was removed from the oven and allowed to cool to room temperature, after which the fabric wrap and internal pressure core were removed.
  • the flexible duct was compressed axially to form wrinkles between the coil turns. When the wrinkles were formed, the length of the duct reduced only slightly.
  • Example #5 A 6" ID flexible duct, 12" long, was manufactured with both the corrosion barrier inner tube and the outer cover tube manufactured from EJ 1650 Insulation Jacketing Product, a PTFE coated fiberglass fabric (Style 332 fiberglass fabric, JPS Industries, Slater, SC; ALGOFLON D60G PTFE dispersion, Ausimont USA, Thorofare, NJ).
  • the PTFE resin content of the coated product was 25% , with 70% of the coating being applied to one side in a gray color.
  • the color of the PTFE coating on the other side was black.
  • the color of the interior surface of the corrosion barrier tube was gray.
  • the color of the exterior surface of the outer tube also was gray.
  • the wire coil was manufactured using #14 tempered spring steel (0.063"), with a 6" ID coil, a 1-1/2" distance between coil turns, and a coil length of 13" .
  • the interior corrosion barrier tube was produced using a h " overlap heat sealed splice and 0.005" PFA film as the melt bondable adhesive.
  • the tube was manufactured with a 6" ID and a 13" length.
  • One-half mil (0.0005") PFA film was thermally tacked to the black exterior surface of the corrosion barrier tube.
  • the outer cover was formed in situ from an EJ 1650 sheet, 13" x 20". Five mil (0.005") PFA film was thermally tacked along one of the black 13" long edges.
  • the internal pressure core was manufactured using a 5" ID metal duct and woven fiberglass fabric (Zetex 2200, 60 oz/sq yd, Newtex Industries, Victor, NY). The fiberglass fabric was wrapped around the metal duct, bringing the diameter of the internal pressure core to 6".
  • the corrosion barrier tube was slipped over the internal pressure core.
  • the coil was then slipped over the corrosion barrier tube.
  • the assembly was wrapped tightly in lightly coated PTFE fiberglass fabric strips that were 1-1/4" " wide.
  • the coating weight of PTFE on the fabric strips was 2-3 oz/sq yd.
  • the fabric strips were wrapped in between the coil turns, providing maximum lamination pressure for bonding the two tubes together.
  • the entire package was placed in a 700 °F convection hot air oven for 15 minutes.
  • the package was suspended by metal rods at each end to ensure uniform heating throughout the package.
  • the assembly was removed from the oven and allowed to cool to room temperature, after which, the fabric wrap and internal pressure core were removed.
  • the flexible duct was compressed axially to form wrinkles between the coil turns. When the wrinkles were formed, the length of the duct reduced only slightly.
  • Example #6 The duct of Example #7 was mounted on a machine designed to effect repeated axial compression at the rate of 69 cycles per minute. One cycle consisted of compressing the duct by 6" and then returning to its original 12" length.
  • the duct was allowed to remain on the machine for 109 minutes of cycle flexing (7550 cycles), at which time a hole developed through both the inner and outer tubes, and the test was discontinued.
  • Example #7 The duct of Example #6 was mounted on the machine described in Example #8.
  • the duct was allowed to remain on the machine for ten hours of cycle flexing (41,400 cycles), at which time a hole developed in both the inner and outer tubes, and the test was discontinued.
  • the coil was manufactured using an extruded PTFE rod that was 3/8" wide x 3/16" thick.
  • a 5" ID helical coil was produced with a 2" distance between coil turns. The original coil length was 29" .
  • Both the interior corrosion barrier tube and outer tube were produced in situ from LFP sheets measuring 17" x 29" .
  • a five mil (0.005") PFA film strip was thermally tacked along one of the 29" long edges on both sheets.
  • PFA film was tacked to one side of the exterior tube sheet to serve as the melt bonding adhesive.
  • the internal pressure core was manufactured using a 4-3/4" ID metal duct and woven fiberglass fabric (Zetex 2200, 60 oz/sq yd, Newtex Industries, Victor, NY). The fiberglass fabric was wrapped around the metal duct, bringing the diameter of the internal pressure core to 5 " .
  • the interior tube sheet was wrapped around the pressure core so that the tacked PFA strip overlapped the opposite edge of the sheet.
  • the PTFE rod was then helically wrapped around the interior sheet.
  • the exterior tube sheet was wrapped around the entire assembly so that the tacked PFA strip along its 29" edge overlapped the opposite edge. Also, the exterior sheet was installed so that the tacked 1 mil PFA film faced inwardly.
  • the assembly was wrapped tightly in lightly coated 3/4" wide PTFE fiberglass fabric strips.
  • the coating weight of PTFE on the fabric strips was 2-3 oz/sq yd. Care was taken to make certain the fabric strips were wrapped in between and over the coil turns, providing maximum lamination pressure.
  • the entire package was placed in a 700 °F convection hot air oven for 30 minutes. The package was suspended by metal rods on each end to ensure uniform heating throughout the package.
  • the package was removed from the oven and allowed to cool to room temperature, after which the fabric wrap and internal pressure core were removed.
  • the flexible duct was compressed by hand to form wrinkles between the coil turns. When the wrinkles were formed, the length of the duct reduced by 10-20% .
  • the outer tube sheet was laminated very tightly to three sides of the PTFE coil, readily displaying its rectangular profile and resulting in a strong bond. Additionally, a section of the flexible duct was removed and dissected to further examine lamination bonds. The outer tube sheet readily tore in every attempt to separate it from the PTFE coil.
  • the pitch of the coil turns was remarkably uniform, indicating that the flat surfaces of the rectangular coil cross section assist in maintaining structural uniformity in the product during the heating process.
  • the completed duct was very flexible. Also, the PTFE coil displayed excellent durability, with an ability to "bounce back" to its original shape when heavily stressed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)

Abstract

L'invention concerne un conduit flexible et non poreux comprenant un serpentin élastique pris entre des tubes intérieur et extérieur en plastique perfluoré. Ces tubes sont stratifiés thermiquement ou thermoscellés l'un à l'autre au niveau de points autres que ceux occupés par le serpentin au moyen d'un adhésif de collage fondu interposé entre ledit serpentin et l'un des tubes.
PCT/US2000/018554 1999-07-09 2000-07-07 Conduit flexible et procede de fabrication correspondant WO2001004531A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU59189/00A AU5918900A (en) 1999-07-09 2000-07-07 Flexible duct and its method of fabrication

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US14301399P 1999-07-09 1999-07-09
US60/143,013 1999-07-09
US15879199P 1999-10-12 1999-10-12
US60/158,791 1999-10-12
US59969400A 2000-06-22 2000-06-22
US09/599,694 2000-06-22

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EP2101095A2 (fr) * 2008-03-12 2009-09-16 Rehau Ag + Co Tuyau ondulé en matière plastique destiné à gainer au moins un câble de capteur de gaz d'échappement
WO2013119920A1 (fr) * 2012-02-08 2013-08-15 Federal-Mogul Powertrain, Inc. Manchon enroulé thermiquement isolant et réfléchissant et son procédé de construction

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EP0473045A1 (fr) * 1990-08-24 1992-03-04 Junkosha Co. Ltd. Tube médical
US5341849A (en) * 1991-11-05 1994-08-30 Markel Corporation Fuel system conduit
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US5655572A (en) * 1995-06-05 1997-08-12 Teleflex Incorporated Hose assembly
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US4385018A (en) * 1977-11-21 1983-05-24 Automation Industries, Inc. Method and apparatus for making insulated, reinforced flexible hose
EP0473045A1 (fr) * 1990-08-24 1992-03-04 Junkosha Co. Ltd. Tube médical
US5341849A (en) * 1991-11-05 1994-08-30 Markel Corporation Fuel system conduit
DE4438840A1 (de) * 1993-11-09 1995-05-11 Phoenix Ag Chemiesicherheitsschlauch
US5427831A (en) * 1993-11-12 1995-06-27 E. I. Du Pont De Nemours And Company Fluoropolymer laminates
US5427831B1 (en) * 1993-11-12 1998-01-06 Du Pont Fluoropolymer laminates
US5679425A (en) * 1994-11-23 1997-10-21 Plumley Companies, Inc. Hose for fuel handling systems
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EP2101095A2 (fr) * 2008-03-12 2009-09-16 Rehau Ag + Co Tuyau ondulé en matière plastique destiné à gainer au moins un câble de capteur de gaz d'échappement
EP2101095A3 (fr) * 2008-03-12 2013-07-17 Rehau AG + Co Tuyau ondulé en matière plastique destiné à gainer au moins un câble de capteur de gaz d'échappement
WO2013119920A1 (fr) * 2012-02-08 2013-08-15 Federal-Mogul Powertrain, Inc. Manchon enroulé thermiquement isolant et réfléchissant et son procédé de construction
KR20140123959A (ko) * 2012-02-08 2014-10-23 페더럴-모걸 파워트레인, 인코포레이티드 열 단열 및 반사 나선형 슬리브 및 그 구성 방법
CN104246337A (zh) * 2012-02-08 2014-12-24 费德罗-莫格尔动力系公司 热绝缘和反射的旋绕套筒及其构造方法
US9297491B2 (en) 2012-02-08 2016-03-29 Federal-Mogul Powertrain, Inc. Thermally resistant convoluted sleeve and method of construction thereof
KR102040346B1 (ko) * 2012-02-08 2019-11-27 페더럴-모걸 파워트레인 엘엘씨 열 단열 및 반사 나선형 슬리브 및 그 구성 방법

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