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WO2004001269A1 - Structure de tuyau flexible relie a une piece d'extremite comprenant une garniture d'etancheite annulaire auto-etanche - Google Patents

Structure de tuyau flexible relie a une piece d'extremite comprenant une garniture d'etancheite annulaire auto-etanche Download PDF

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Publication number
WO2004001269A1
WO2004001269A1 PCT/DK2003/000411 DK0300411W WO2004001269A1 WO 2004001269 A1 WO2004001269 A1 WO 2004001269A1 DK 0300411 W DK0300411 W DK 0300411W WO 2004001269 A1 WO2004001269 A1 WO 2004001269A1
Authority
WO
WIPO (PCT)
Prior art keywords
sealing
flexible pipe
pipe
gasket
end fitting
Prior art date
Application number
PCT/DK2003/000411
Other languages
English (en)
Inventor
Jesper Ries
Original Assignee
Nkt Flexibles I/S
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 Nkt Flexibles I/S filed Critical Nkt Flexibles I/S
Priority to AU2003240433A priority Critical patent/AU2003240433A1/en
Publication of WO2004001269A1 publication Critical patent/WO2004001269A1/fr

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Classifications

    • 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
    • F16L17/00—Joints with packing adapted to sealing by fluid pressure
    • F16L17/02—Joints with packing adapted to sealing by fluid pressure with sealing rings arranged between outer surface of pipe and inner surface of sleeve or socket
    • F16L17/03—Joints with packing adapted to sealing by fluid pressure with sealing rings arranged between outer surface of pipe and inner surface of sleeve or socket having annular axial lips
    • F16L17/035—Joints with packing adapted to sealing by fluid pressure with sealing rings arranged between outer surface of pipe and inner surface of sleeve or socket having annular axial lips the sealing rings having two lips parallel to each other
    • 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
    • F16L33/00—Arrangements for connecting hoses to rigid members; Rigid hose connectors, i.e. single members engaging both hoses
    • F16L33/01—Arrangements for connecting hoses to rigid members; Rigid hose connectors, i.e. single members engaging both hoses adapted for hoses having a multi-layer wall
    • 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
    • F16L33/00—Arrangements for connecting hoses to rigid members; Rigid hose connectors, i.e. single members engaging both hoses
    • F16L33/26—Arrangements for connecting hoses to rigid members; Rigid hose connectors, i.e. single members engaging both hoses specially adapted for hoses of metal

Definitions

  • the present invention relates to a pipe system for transporting a fluid substance (e.g. oil or gas or a mixture thereof) and especially to the problems of sealing of a connection of a flexible pipe to an end fitting for 10 connecting the flexible pipe to an installation or to another pipe.
  • a fluid substance e.g. oil or gas or a mixture thereof
  • the invention relates specifically to: A pipe structure for transporting a fluid substance in a physical environment, the pipe structure comprising a flexible pipe connected to an end fitting, the flexible pipe comprising a sealing layer, 15 the flexible pipe having a longitudinal axis, the end fitting surrounding the sealing layer, the end fitting and the sealing layer having a common to-be- sealed interface and together defining a sealing cavity.
  • the present invention further relates to a method of sealing a pipe structure.
  • the invention may e.g. be useful in applications such as transport of pressurized liquids and gases (e.g. hydrocarbons, water, etc.) at elevated temperatures in marine environments.
  • pressurized liquids and gases e.g. hydrocarbons, water, etc.
  • Flexible pipes are e.g. used in the off-shore industry for transporting oil, gas, water and other fluids between off-shore installations etc. Pressures in the range from 10 to 500 bar (1-50 MPa) and temperatures between -40 and 130 35 °C are commonplace. It is for several reasons (e.g. environmental and economic) important to avoid that significant amounts of the fluid transported within the flexible pipe escapes to the (typically marine) environment. This puts focus on the tightness of the flexible pipe and of its connection to an end fitting for connecting the flexible pipe to an installation (at land or on a vessel at sea or on the seabed) or for connecting to another pipe, e.g. another flexible pipe or a rigid pipe.
  • US-6,019,137 deals with a flexible pipe for conveying hydrocarbons, typically at temperatures > 80 °C, e.g. from offshore wellheads to the surface.
  • the pipe is at its ends fitted with connection end-pieces.
  • Sealing between a sealing barrier and the end-piece is provided by a metal sealing bush that is crimped on the sealing barrier and held axially in place in the end-piece by means of a ring pushing the bush in an axial direction and (in cooperation with a conical form of the annular housing) causing it to press into the sealing barrier.
  • Other solutions comprise combinations of metal and polymer gaskets pressed together by an axial and/or radial pressure in the form of a cooperating, appropriately fastened ring.
  • US-5,720,503 describes a sealing system for a rotatable fluid conduit coupling for an off-shore swivel.
  • the sealing system comprises a sealing ring of a resilient material located in an annular recess in ring-shaped inner and outer, non-flexible (steel) parts separated by a clearance which is to be sealed by the sealing ring, the sealing ring functioning under a positive pressure difference in the clearance.
  • the sealing ring comprises a body connected to separated, flexible legs, the annular recess comprising deformation limiting means resisting compression of the legs towards one another upon application of a negative pressure across the annular recess.
  • the problem of the prior art is that the sealing element or elements must be subject to a compressive contact force built-into the pipe structure around the sealing element, and that typically a substantial margin in the form of an extra large compressive force must be provided to be able to account for dimensional changes in the pipe structure (e.g. due to temperature induced creep) during installation and operation. Further, to sustain the sealing pressure between the sealing element and walls of the flexible pipe and the end fitting, these walls have to be relatively rigid (e.g. be of a relatively thick non-flexible construction (e.g. of steel) or requiring a rigid insert, a rigid carcass or the like in the flexible pipe beneath the sealing element).
  • relatively rigid e.g. be of a relatively thick non-flexible construction (e.g. of steel) or requiring a rigid insert, a rigid carcass or the like in the flexible pipe beneath the sealing element.
  • the object of the present invention is to provide a pipe structure with a sealing that is relatively simple and able to be self-sealing in the sense that it relaxes the need for built-in compressive forces working on the sealing part.
  • a pipe structure for transporting a fluid substance in a physical environment comprising a flexible pipe connected to an end fitting, the flexible pipe comprising a sealing layer, the flexible pipe having a longitudinal axis, the end fitting surrounding the sealing layer, the end fitting and the sealing layer having a common to-be-sealed interface and together defining a sealing cavity
  • the pipe structure further comprising a sealing part for sealing said to-be-sealed interface, said sealing part being contained totally or partly in said sealing cavity, said sealing part comprising an annular gasket surrounding said sealing layer and having an elongatedd curved cross section forming a first and a second flange section and with an outer face constituting a sealing face and an inner face constituting a non-sealing face of the annular gasket wherein the sealing face of said first annular flange section is sealing against said sealing layer of said flexible pipe and the sealing face of said second annular flange section is sealing against said end fitting, when said sealing
  • the annular gasket forms an elongatedd curved part when viewed in a cross section through a longitudinal axis of the flexible pipe.
  • 'an elongated curved part' (referring to a cross section of an annular gasket when viewed perpendicular to an annular direction) is taken to mean a part that has a shape allowing it to be positioned in such a way that it bridges the interface to be sealed and has an edge of contact with each of the sealing layer and the end fitting. Examples of such a shape are a U-shape, a V-shape or any other like shape that bridges the interface to be sealed and conforms to the shape of the sealing cavity defined by the sealing layer and the end fitting.
  • An elongated curved part may e.g. be constituted by an intermediate body connected to two elongated elements/legs/lips or simply two elongated elements physically connected at one of their ends.
  • An elongated curved part may e.g. in a 'folded out' or non mounted situation have an essentially rectangular cross section (possibly with rounded corners or tapered ends), i.e. comprise two essentially parallel and relatively long edges connected by two relatively short, curved or pointed or straight, etc., curves.
  • the gasket comprises an annular part with a sealing surface (i.e.
  • the 'to-be-sealed interface' is taken to mean the clearance or common surface of contact between the end fitting and the sealing surface of the flexible pipe.
  • the term 'sealing' is taken to mean to - during normal operating conditions - prevent significant amounts of the fluid (e.g. oil or gas or water) transported by the flexible pipe to escape to the physical environment around the pipe structure or vice versa to prevent significant amounts of the fluid (e.g. marine water) present in the immediate physical environment surrounding the pipe structure to enter and mix with the fluid transported by the flexible pipe.
  • 'Significant amounts' are in the present context taken to mean - ideally zero, but in practice - within the specifications of the flexible pipe structure under normal operating conditions.
  • the solution according to the invention provides an alternative to a traditional 'solid-type' sealing element (such as an O-ring or other geometrically formed solid elements). It provides a design freedom in adapting the area and shape of the surface of contact with the to-be-sealed surfaces, in choice of materials, in combination with other functional elements, etc. Further, a sealing part according to the invention is more tolerant towards shrinkage, swelling or creep of the gasket itself and of the materials constituting the to- be-sealed surfaces, which may comprise polymeric materials, e.g. Polyamide (PA), Polyethylene (PE) or Polyvinylidene fluoride (PVDF).
  • PA Polyamide
  • PE Polyethylene
  • PVDF Polyvinylidene fluoride
  • a sealing part according to the invention an 'oversize' of the surfaces of contact may be designed in, thereby taking account of future possible effects due to hydrocarbon fluid exposure, temperature (or other) influences.
  • the sealing properties of a gasket according to the invention are not significantly dependent on the volume of the gasket but mainly on the surface area of contact with the to-be-sealed surfaces.
  • Appropriate materials for a gasket include metals (e.g. stainless steel, (e.g. AISI 316), Duplex steel, Inconel® (a nickel-iron-chromium alloy containing various amounts of other metals, e.g. Nb, Mo, Ti), polymers (e.g. fluor polymers, e.g. polytetrafluoroethylene (PTFE), polyetheretherketone (e.g. PEEKTM)) or metals coated with polymers.
  • metals e.g. stainless steel, (e.g. AISI 316), Duplex steel, Inconel® (a nickel-iron-chromium alloy containing various amounts of other metals, e.g. Nb, Mo, Ti)
  • polymers e.g. fluor polymers, e.g. polytetrafluoroethylene (PTFE), polyetheretherketone (e.g. PEEKTM)
  • metals e.g. stainless steel, (e.g. AISI 316
  • the 'longitudinal axis' of the flexible pipe is taken to mean the centre axis of the flexible pipe when it is held in a straight line (un-curved) configuration.
  • the physical environment of the pipe structure is in an embodiment of the invention a marine environment such as a deep sea (salt water) environment, e.g. depths of typically 500-1000 m (but including several km).
  • a marine environment such as a deep sea (salt water) environment, e.g. depths of typically 500-1000 m (but including several km).
  • the physical environment may be constituted by a fresh water environment or by the atmosphere (e.g. in case of a use fully or partially above the sea or on land).
  • the sealing cavity has a wedge-formed cross section when viewed in a cross section comprising the longitudinal axis of the flexible pipe.
  • the angle between the sealing layer of the flexible pipe and the part of the end fitting to be sealed in the sealing cavity (together making up the wedge-formed sealing cavity) is in the range 10-90°, such as 20-60°.
  • the tip of the wedge-formed cavity is rounded off by forming the end-fitting-part of the sealing cavity.
  • the part of the sealing cavity comprising the surfaces of contact with the gasket has a U-or V-shaped cross section.
  • the gasket has a sealing surface that describes a surface of revolution with an axis of revolution that coincides with the longitudinal axis of the flexible pipe. This has the advantage of providing a symmetric element which is relatively easy to manufacture.
  • the gasket may take many other forms, e.g. more complex forms adapted to the particular form of the end fitting and the sealing layer.
  • the sealing part exerts a minimum contact force on the sealing layer and the end fitting, where the contact force has a component in a radial direction towards and opposite to the centre of the flexible pipe, respectively.
  • a minimum contact force' is in the present context taken to mean a contact force sufficient for maintaining the sealing part in place in the sealing cavity after mounting and during normal operating conditions of the pipe structure.
  • the minimum contact force is adapted to maintaining the sealing part in place in the sealing cavity in a situation where no internal pressure is applied to the pipe structure (e.g. during installation, before operation has commenced).
  • the sealing part comprises pressing means for pressing the sealing faces of said first and second annular flanges against, respectively, the sealing layer and the end fitting.
  • the gasket comprises pressing means in that the gasket is resilient and adapted for pressing the sealing face of said first and second flange sections of the sealing surface against, respectively, the sealing layer of the flexible pipe and the end fitting, it is further ensured that the sealing element is self-sealing because the flexibility of the gasket is able to compensate for variations in the diameter of the sealing layer (e.g. a liner) along its length. Such a variation may be present due to the margins of the manufacturing process (e.g. an extrusion process).
  • the self-adaptation provided by the built-in flexibility of the gasket has the advantage of easing the process of mounting the flexible pipe to the end fitting.
  • the sealing part comprises pressing means in the form of a separate pressing element adapted for pressing the sealing face of said first and second flange sections of the sealing surface against, respectively, the sealing layer of the flexible pipe and the end fitting.
  • This has the advantage of contributing to keeping the gasket in close contact with the relevant parts of the sealing layer of the flexible pipe and the end fitting, thereby improving the self-sealing ability of the part.
  • a pressing element in the form of an annular body is mounted to cooperate with the gasket (e.g. by press fitting, latching the pressing element and the gasket together) thereby pressing the two sections of the sealing surface of the gasket against the to-be-sealed surfaces.
  • the pressing element is itself resilient, thereby further improving the adaptability to mechanical tolerances of the pipe structure.
  • the pressing element has an essentially elliptical cross section.
  • An appropriate material for making a pressing element is a metal or a metal coated with a polymer.
  • the pressing element comprises an annular spring.
  • This provides a simple and effective way of creating a force in support of keeping the gasket in contact with the to-be-sealed surfaces in the sealing cavity.
  • the annular spring takes the form of a canted-coil spring (cf. e.g. US-4, 655,462 and products marketed by the company Bal Seal Engineering Inc, Foothill, California), which has the advantage of providing a constant force over a large spring deflection, thus being well suited for accommodating variations in physical dimensions of the to-be-sealed parts due to mechanical tolerances, temperature variations, creep, wear, etc.
  • the spring may be a helically wound flat spring.
  • an annular spring is stainless steel (e.g. AISI 302) or other resilient metals or alloys.
  • a stainless steel spring has the advantage of being mechanically strong and resistant to corrosion and aggressive chemicals.
  • an O-ring type seal which functions as a resilient spring, may be used as a pressing element.
  • the sealing part comprises an annular gasket of a fluor polymer, e.g. PTFE, partially surrounding a canted-coil spring of stainless steel.
  • a fluor polymer e.g. PTFE
  • a chemically aggressive environment such as liquid acid or ammonia
  • a part of the non-sealing face of the annular gasket faces the direction of the pressure from the fluid possibly entering the sealing cavity from the interior or exterior of the tube.
  • the surfaces of contact of the sealing cavity with the annular gasket face the direction of the pressure from the fluid possibly entering the sealing cavity from the interior or exterior of the tube.
  • the sealing cavity is in fluid contact with the inside of the flexible pipe, the fluid substance thereby exerting a compressive force on the non-sealing face of the gasket.
  • This has the advantage of contributing to the self-sealing properties of the pipe structure, since the pressure from the fluid flowing in the flexible pipe will further press the sections of the sealing surface of the gasket against the to-be-sealed parts of the sealing layer and the end fitting, respectively (possibly in combination with a pressing element).
  • the fluid substance transported in the flexible pipe is pressurized at a pressure in the range 10-1000 bar (i.e. 1-100 MPa), preferably in the range 1-520 bar (1-
  • the sealing-cavity is in fluid contact with the outside of the flexible pipe.
  • the term 'in fluid contact' between two volumes is in the present context taken to mean that the pressure difference between one volume and the other is at least partially eliminated, e.g. fully eliminated, e.g. by a channel allowing fluid from one volume to flow to the other volume.
  • the sealing part further comprises a blocking element adapted for limiting the movement of the sealing face of the first and second flange sections of the gasket relative to each other when subject to a pressure from the physical environment.
  • a blocking element adapted for limiting the movement of the sealing face of the first and second flange sections of the gasket relative to each other when subject to a pressure from the physical environment.
  • the blocking element is an integral part of the end-fitting in that it constitutes a part of the wall of the sealing cavity.
  • the pipe structure comprises several individual sealing parts located in the same sealing cavity.
  • individual sealing elements are mounted to abut each other in a direction of the longitudinal axis of the flexible pipe.
  • the pipe structure comprises several individual sealing parts located in different sealing cavities.
  • the sealing parts are arranged in individual cavities positioned along a direction of the longitudinal axis of the flexible pipe.
  • the pipe structure comprises two sealing parts each part being located in its own sealing cavity, one sealing cavity being in fluid connection with the interior of the pipe, the other sealing cavity being - at least in certain situations (e.g. in a fault situation or when the pipe is not at operational pressure, e.g. during installation) - in fluid connection with the physical environment.
  • the sealing layer is constituted by an elastic inner liner.
  • an elastic inner liner is taken to mean a tube made of an elastic material, e.g. PA, PE or PVDF.
  • the flexible pipe is an un-bonded flexible pipe, preferably comprising a tube formed liquid tight inner liner and one or more armour layers, preferably two or more armour layers.
  • the flexible pipe may be of a bonded type.
  • the flexible pipe (bonded as well as un-bonded) may further comprise one or more layers made of composite materials.
  • the flexible pipe comprises two layers of helically wound armouring wires, the winding angles with respect to the longitudinal direction of the flexible pipe being between 50 and 60 degrees, such as between 53 and 56 degrees, the armour layers preferably comprising helically wound wires which are wound in opposite directions.
  • the flexible pipe comprises an inner armouring layer such as a carcass.
  • the flexible pipe comprises a pressure armouring and a tensile armouring, where the tensile armouring comprises two layers of helically wound armouring elements wound in opposite directions, the winding angles with respect to the longitudinal direction of the flexible pipe being between 25 and 40 degrees.
  • the present invention further provides a method of sealing an interface between a flexible pipe and an end fitting, the flexible pipe defining a longitudinal axis, the end fitting surrounding a sealing layer of the flexible pipe thereby defining a to-be-sealed interface and a sealing cavity, the method comprising the steps of a) providing a sealing part totally or partially contained in said sealing cavity, the sealing part comprising an annular gasket surrounding said sealing layer and having an elongated curved cross section forming a first and a second flange section and with an outer face constituting a sealing face and an inner face constituting a non-sealing face of the annular gasket, b) arranging that the sealing face of said first annular flange section is sealing against said sealing layer of said flexible pipe and the sealing face of said second annular flange section is sealing against said end fitting, when said sealing part is mounted in said sealing cavity, and thereby arranging that said sealing faces are pressed against, respectively, said sealing layer and said end fitting in said sealing cavity.
  • the method has
  • An embodiment of the invention provides a sealing arrangement between a flexible pipe and an end fitting connected to the end fitting, wherein the flexible pipe is constituted by a carcass, an inner liner, a pressure armouring, a tensile armouring and optionally an outer sheath, and wherein the sealing arrangement is provided between the inner liner and the end fitting.
  • the object is achieved by a sealing arrangement between a flexible pipe and an end fitting connected to the pipe, wherein the flexible pipe is constituted by a carcass, an inner liner, a pressure armouring, a tensile armouring and optionally an outer sheath, and wherein the sealing arrangement is provided between the inner liner and the end fitting characterized in that the sealing arrangement is constituted by at least one spring, where the spring or springs is/are partly surrounded by an open gasket part.
  • the sealing arrangement according to the invention has a relatively large region of operation in the sense that it will function even if the inner liner is subject to creep, i.e. the wall thickness is reduced, or in case of large margins on the dimensions of the inner liner.
  • the gasket part is constituted by a groove having 3 sides and where two of the sides are formed as flanges that are perpendicular to the third side.
  • the flanges face the fluid being transported in the pipe. This has the advantage that the pressure on the gasket part against the liner is increased because the fluid being transported exerts a pressure into the groove. In an embodiment of the invention, the flanges face the external surroundings of the flexible pipe. This has the advantage that it is ensured that the pressure on the gasket part against the liner will always be sufficient because there will always be a fluid around the exterior surroundings of the pipe which exerts a pressure on the sealing arrangement.
  • the sealing arrangement is constituted by two springs where the third side of the matching gasket parts abut each other. This has the advantage of ensuring a reliable sealing in all operational conditions irrespective of fluid is transported by the pipe or not.
  • the gasket part is made of fluor polymers (Teflon®).
  • Teflon® fluor polymers
  • the spring is expediently embodied as a coil or made of stainless steel, which provides some mechanical advantages and chemically resistant properties.
  • FIG. 1 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket placed in a sealing cavity according to the invention
  • FIG. 1.a and 1.b illustrating, respectively, a V-shaped and a U- shaped gasket
  • FIG. 2 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket placed in a sealing cavity with a blocking element according to the invention
  • FIG. 2. a illustrating a blocking element that is an integral part of a wall of the end fitting in the sealing cavity and
  • FIG. 2.b illustrating a blocking element that is a separate part
  • FIG. 3 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket placed in a sealing cavity with a fixed blocking element according to the invention, illustrating a fluid contact between the sealing cavity and the interior of the flexible pipe,
  • FIG. 4 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket placed in a sealing cavity with a separate pressing element according to the invention, illustrating a fluid contact between the sealing cavity and the interior of the flexible pipe, FIG 4. a. showing a pressing element of a solid material and FIG. 4.b a pressing element comprising a rigid core surrounded by a flexible material,
  • FIG. 5 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket placed in a sealing cavity with a separate resilient pressing element according to the invention, the pressing element comprising a tubular elastic spring,
  • FIG. 6 shows details of a cross section of a pipe structure with two sealing parts in separate sealing cavities
  • FIG. 6. a. illustrating an embodiment with a gasket and a pressing element in one sealing cavity and a gasket and a blocking element in the other
  • FIG. 6.b illustrating an embodiment with a gasket and a pressing element in both sealing cavities, the gaskets being mutually mirror symmetrically arranged
  • FIG. 7 shows an example of a flexible pipe suitable for being connected to an end fitting in a pipe structure according to the invention
  • FIG. 8 shows a conventional construction of a flexible pipe for offshore use
  • FIG. 9 shows in an enlarged scale parts of the pipe of FIG. 8 connected to an end fitting with a sealing arrangement according to the invention.
  • FIGs. 1-5 show cross sections of parts of a flexible pipe structure 100 in a plane comprising a longitudinal axis (cf. axis 170 in FIG. 3) of the flexible pipe.
  • FIG. 1 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket 104 placed in a sealing cavity 103 according to the invention.
  • FIG. 1.a shows a cut out of a cross section of a flexible pipe structure 100 comprising an end fitting part and flexible pipe part, the end fitting comprising a housing 101 and the flexible pipe comprising a sealing layer 102.
  • the sealing layer 102 has an inner surface 1021 facing the interior of the flexible pipe (e.g. a fluid transported by the pipe or another interior layer) and an outer sealing surface 109 facing the end-fitting at least around the location of the sealing part in the sealing cavity.
  • a sealing part comprising an annular gasket 104 is positioned around the sealing layer 102 in a sealing cavity 103 formed at the interface between the housing of the end fitting and the sealing layer.
  • the gasket 104 has a V-profile comprising two sections or legs in the cross section shown adapted to fit the wedge-formed profile of the sealing cavity around the location of the gasket.
  • the two legs i.e. constituting annular surfaces when viewed in three dimensions
  • the gasket in FIG. 1.a is made of a resilient material to provide a basic minimum force against the surfaces of contact. It is preferred that the pressure in the sealing cavity 103 on the non-sealing face 105 of the gasket 104 is larger than or equal to the pressure in the clearance 111 on the sealing face 106 of the gasket.
  • FIG. 1.b shows a similar cut out as that of FIG. 1.a.
  • the annular gasket 104 has a U-shape in the cross section of the flexible pipe including a longitudinal axis of the pipe.
  • the sealing cavity constituted by the faces 110 and 109 of, respectively, the housing 101 of the end fitting and the sealing layer 102 is similarly shaped around the location of the gasket and adapted to appropriately accommodate the gasket thereby yielding a radial minimum force on the surfaces of contact 110 and 109 between the resilient gasket and the sealing cavity.
  • FIG. 2 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket 104 placed in a sealing cavity 103 with a blocking element 114 according to the invention.
  • the blocking element cooperates with the gasket in that it limits the flexing of the legs of the gasket towards each other.
  • FIG. 2. a shows a blocking element 114 that is an integral part of a wall of the housing 101 of the end fitting in the sealing cavity 103.
  • the protruding surface 115 of the blocking element 114 forces the sealing faces 108, 107 of the legs 1041 , 1042 of the gasket 104 against the to-be-sealed faces of the sealing cavity 103, if the pressure in the clearance 111 is larger than the pressure in the sealing cavity 103. This may e.g. occur if the hydrostatic pressure from the physical environment is larger the pressure in the flexible pipe (e.g. during installation of the pipe where the pipe may be un-pressurized).
  • FIG. 2.b shows an alternative embodiment of the invention, where the blocking element 114 is a separate part whose movement in a direction parallel to the flexible pipe is limited by a wall of the housing 111 of the end fitting, the wall having a face 116 that engages the blocking element and stops its movement in case the pressure in the clearance 111 is larger than the pressure in the sealing cavity 103, thereby forcing the sealing faces 108, 107 of the legs of the gasket 104 against the to-be-sealed faces of the sealing cavity 103.
  • the blocking element 114 may preferably be made of a material that is more rigid than the gasket.
  • FIG. 3 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket 104 placed in a sealing cavity 103 with a fixed blocking element 114 according to the invention, illustrating a fluid contact between the sealing cavity and the interior 150 of the flexible pipe.
  • a partial cross section of the pipe structure is shown including diametrically opposite cross sections of the sealing cavity (as indicated by the longitudinal axis of symmetry 170 of the flexible pipe).
  • the interior 150 of the flexible pipe is only partially shown in that a possible enlargement of the opening of the pipe is indicated by marks 160.
  • only a part of the housing of the end fitting is shown as indicated by the curved outer shape of the housing 101.
  • FIG. 3 is similar to that of FIG. 2. a but deviates in that an opening 112 between the sealing layer 102 and the end fitting housing 101 allows a fluid contact between the interior 150 of the flexible pipe and the sealing cavity 103 to ensure that the pressure from the fluid in the pipe is present in the sealing cavity (as indicated by arrows 151 ) and exerts a corresponding force on the non-sealing face 105 of the gasket 104, thereby improving the sealing properties of the structure.
  • an opening 113 may be formed in the wall of the housing 101 of the end fitting to allow a fluid contact between the interior 150 of the flexible pipe and the sealing cavity 103.
  • the pressure from the external environment 180 may fully or partially be present in the clearance 111 between the sealing layer and the end fitting housing as indicated by the arrow 181.
  • the sealing part will ensure a proper tight sealing of the interface 1 ) due to the blocking element 114, and 2) because the equal pressure in the interior of the pipe and in the sealing cavity allows the sealing layer (which in a preferred embodiment is a flexible liner of the pipe, cf. layer 3 in FIG. 7) to be flexible without deforming into the sealing cavity (and thereby hampering the sealing properties of the gasket).
  • FIG. 4 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket 104 placed in a sealing cavity 103 with a separate pressing element 124 according to the invention.
  • the pressing element 124 is partially enclosed by the gasket 104.
  • the pressing element serves the purpose of forcing the sealing faces 108, 107 of the legs 1041 , 1042 of the gasket 104 against the to-be-sealed faces of the sealing cavity 103.
  • the embodiments in FIGs. 4. a and 4.b are similar to those of FIG. 3 in that they include channels 112 and 111 for allowing fluid contact between the sealing cavity and, respectively, the interior of the flexible pipe and the exterior physical environment 180 as indicated by arrows 151 and 181 , respectively.
  • the pressing element 124 of FIGs. 4. a and 4.b additionally performs the function of the blocking element 114 of FIGs. 2 and 3.
  • FIG. 4. a shows a gasket 104 partially surrounding a pressing element 124
  • the pressing element comprises a slightly wedge-shaped body of a relatively rigid material, e.g. steel or a ceramic material, the body being adapted so that it expands the distance between the legs 1041 , 1042 of the gasket in its resting position and additionally when moved in an axial direction of the flexible pipe towards the gasket.
  • the part of the wall 115 of the sealing cavity facing and contacting the pressing element is formed so that it cooperates with the pressing element and thereby ensures that the pressing element remains relatively fixed in case of a 'reverse pressure' (i.e. if the pressure from the external environment exceeds the pressure in the sealing cavity) and that the pressure is distributed relatively evenly over the contacting face of the pressing element 124 with the wall 115 of the sealing cavity.
  • FIG. 4.b shows a gasket partially surrounding a pressing element 124 as in FIG. 4. a where the pressing element comprises a rigid core 117 surrounded by a resilient material.
  • FIG. 5 shows details of a cross section of a pipe structure with a sealing part comprising a sealing gasket placed in a sealing cavity with a separate pressing element according to the invention.
  • the pressing element 124 comprises a tubular elastic spring 118 partially enclosed by the annular gasket 104.
  • the tubular spring takes the form of a canted-coil spring.
  • the face 115 of the wall of the sealing cavity 103 is adapted to receive the pressing element in case of a 'reverse pressure' in the sealing cavity so that sealing faces 108, 107 of the gasket are forced against the walls of the sealing cavity to ensure a tight sealing thereby additionally performing the function of a blocking element (cf. 114 on FIGs. 2 and 3).
  • the pressing element 124 may preferably comprise a rigid core 117.
  • FIG. 6 shows details of a cross section of a pipe structure with two sealing parts in separate sealing cavities.
  • FIG. 6. a illustrates an embodiment of the invention with a gasket 1041 and a pressing element 1241 in one sealing cavity 1031 and a gasket 1042 and a blocking element 1142 in the other sealing cavity 1032.
  • the pipe structure 100 comprises two separate sealing cavities 1031 and 1032 each containing an annular gasket 1041 , 1042 and a pressing element 1241 , 1242, the gaskets being mutually mirror symmetrically arranged in their respective sealing cavities.
  • the sealing cavity 1031 containing gasket 1041 and pressing element 1241 has the function as described for FIGs. 1-5 of sealing the interface against fluid escaping from the interior of the pipe to the surrounding environment 180.
  • the sealing cavity 1032 containing gasket 1042 and, respectively, blocking element 1142 (FIG. 6.a) and pressing element 1242 (FIG. 6.b), on the other hand, has the function of preventing e.g. salt water from a surrounding marine environment in penetrating into the interior of the flexible pipe. The way of functioning is as described for FIGs. 2-3 and FIGs 4-5, respectively.
  • FIG. 7 shows an example of a flexible pipe 1 suitable for being connected to an end fitting in a pipe structure 100 according to the invention (cf. FIGs. 1- 6).
  • FIG. 7 shows an ordinary structure of a flexible reinforced pipe 1 with its different layers.
  • the flexible pipe in FIG. 7 consists of an inner liner 3 optionally surrounding one or more other layers 20 that together form an inner pipe.
  • the inner liner 3 serves the purpose of preventing flow of fluids between the interior of the pipe and the external physical environment.
  • the sealing layer may typically be the inner liner 3 (corresponding to 102 in FIGs. 1-6) which is surrounded by an end fitting and the to-be-sealed interface is the interface between the inner liner and the housing of the end fitting.
  • One or more layers of profiles 41 , 42 are helically wound externally on the inner liner 3, said profiles forming turns of a great angle (e.g. 80-90°) relative to the longitudinal direction of the pipe. Because of the great angle, the profiles will primarily be capable of absorbing radial forces that occur because of internal or external pressures. The internal pressures occur in the operation of the pipe. The external pressures are caused partly by the hydrostatic pressure of the surroundings and partly by mechanical impacts during the laying of the pipe.
  • the turns thus form a pressure reinforcement which prevents the inner liner 3 from bursting because of a high pressure on the inner side of the pipeline, or from collapsing because of a high pressure on the outer side of the pipeline. It is additionally shown in FIG. 7 that the pressure reinforcement has externally applied thereto a tensile reinforcement, which consists of one or more layers 61 , 62 comprising helically wound armouring wires.
  • An intermediate jacket may be interposed between the pressure reinforcement and the tensile reinforcement, serving the purpose of preventing fluids from migrating between the pressure reinforcement and the tensile reinforcement.
  • the tensile reinforcement 61 , 62 is usually composed of two helically wound layers of steel profiles with opposite winding direction.
  • the armouring wires may alternatively be made of other materials, e.g. composite materials.
  • FIG. 8 shows a flexible pipe 1 which for example may be used for the transport of gasses and oil at large depths of the sea.
  • the pipe comprises a carcass 2 surrounded by a tight inner liner 3.
  • a pressure armouring layer 4 is arranged which again is surrounded by a tensile armouring layer 6 which as shown is constituted by two layers.
  • an outer sheath 7 is arranged on the outside of the tensile armouring layer 6, which is constituted by two layers.
  • An end fitting is connected to the pipe by means of bolts, one of which is referred to as 10, the end fitting being constituted by a casing 9, a ring 5 with a gasket seat 15 and a sealing ring 12 which is deposited in a minor groove in the ring 5.
  • a holding member 11 on the inner liner whose function is to fix the inner liner in its axial position.
  • FIG. 9 shows a dotted line 21 and an arrow which symbolize that the area which in the direction of the arrow points into the end fitting is completely tight so that fluid cannot escape in this area.
  • a sealing arrangement is provided in the gasket seat 15, the sealing arrangement consisting of a spring 14 and a gasket part 13 which has the form of a groove 8 being defined by three sides 16, 17, 18, where the sides 16 and 17 are constituted by flanges extending at right angles from the ends of the side 18.
  • a spring 14 is placed, the spring being e.g. made of stainless steel.
  • the spring may expediently be manufactured as a coil running in the groove 8 along a path defined by the curvature of the inner liner.
  • the sealing arrangement works in the following way:
  • fluid will be able to exert a pressure against the interior of the gasket part 13 because the groove 8 is open towards the inner liner of the flexible pipe.
  • the sealing arrangement is implemented with two gasket parts whose 3 rd side abut each other thereby creating two open grooves in the gasket parts so that one groove is open towards the interior of the pipe whereas the other groove is open towards the outer surroundings whereby the sealing between the liner and the gasket parts becomes extra secure.
  • fluor polymer Teflon®
  • Teflon® fluor polymer

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Gasket Seals (AREA)

Abstract

L'invention concerne une structure de tuyau (100) permettant de transporter une substance fluide dans un environnement physique (180). L'invention concerne notamment les problèmes d'étanchéification d'une interface à étanchéifier (111) située entre une couche d'étanchéité (102) d'un tuyau flexible et une pièce d'extrémité (101) permettant de relier le tuyau flexible à une installation ou à un autre tuyau. L'objet de la présente invention est de fournir une structure de tuyau présentant un joint d'étanchéité qui est relativement simple et pouvant être auto-étanche dans le sens où il rend inutile les forces de compression intégrées travaillant sur l'élément d'étanchéité. Le problème est résolu étant donné que la structure de tuyau (100) comprend également un élément d'étanchéité permettant de rendre étanche l'interface à étanchéifier (111), l'élément d'étanchéité comprenant une garniture annnulaire (104) pressant la garniture annulaire contre, respectivement, la couche d'étanchéité (102) et la pièce d'extrémité (101), par exemple à l'aide d'un élément de pressage (124). L'invention présente l'avantage de fournir une variante à l'élément d'étanchéité de « type solide » classique (tel qu'un joint torique ou d'autres éléments solides de forme géométrique). L'invention permet une liberté de conception au niveau de l'adaptation de la zone et de forme de la surface de contact avec des surfaces destinées à être scellées, dans le choix des matériaux, en combinaison avec d'autres éléments fonctionnels, etc. L'invention peut par exemple être utilisée en liaison avec le transport de fluides et de gaz sous pression (par exemple, hydrocarbures, eau, etc.) dans un tuyau flexible à des températures élevées dans des milieux marins.
PCT/DK2003/000411 2002-06-20 2003-06-19 Structure de tuyau flexible relie a une piece d'extremite comprenant une garniture d'etancheite annulaire auto-etanche WO2004001269A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003240433A AU2003240433A1 (en) 2002-06-20 2003-06-19 Flexible pipe structure connected to an end fitting comprising a self-sealing annular sealing gasket

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKPA200200942 2002-06-20
DKPA200200942 2002-06-20

Publications (1)

Publication Number Publication Date
WO2004001269A1 true WO2004001269A1 (fr) 2003-12-31

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008037274A1 (fr) * 2006-09-26 2008-04-03 Holger Knappe système de fermeture de la partie d'extrémité d'un tube ou d'un récipient tubulaire
WO2012110637A1 (fr) 2011-02-18 2012-08-23 Technip France Conduite tubulaire flexible pour le transport d'un fluide pétrolier tel qu'un fluide polyphasique ou un gaz.
WO2012126999A1 (fr) 2011-03-24 2012-09-27 Technip France Embout de connexion d'une conduite tubulaire flexible pour le transport d'un fluide en milieu marin et procédé de montage d'un tel embout de connexion
WO2014174244A1 (fr) * 2013-04-24 2014-10-30 Wellstream International Limited Élément de bague d'étanchéité
US11378207B2 (en) 2019-11-22 2022-07-05 Trinity Bay Equipment Holdings, LLC Swaged pipe fitting systems and methods

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2259453A (en) * 1938-12-08 1941-10-21 Walter O Beyer Coupling unit
DE957704C (de) * 1955-03-23 1957-02-07 Ziefle Kg Eisenbau Albert Abdichtung fuer Rohrverbindungen
US2921801A (en) * 1955-03-21 1960-01-19 Walter O Beyer Flexible pipe coupling
CH571678A5 (en) * 1974-09-09 1976-01-15 Meury Kurt Pipe or hose union - has clamping ring distorted into truncated cone on pulling up
US5720503A (en) * 1995-11-08 1998-02-24 Single Buoy Moorings Inc. Sealing sytem--anti collapse device
WO1999019656A1 (fr) * 1997-10-14 1999-04-22 Nkt Flexibles I/S Ensemble constitue d'un tuyau souple et d'un raccord d'extremite
US6019137A (en) * 1996-01-11 2000-02-01 Coflexip Flexible pipe

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2259453A (en) * 1938-12-08 1941-10-21 Walter O Beyer Coupling unit
US2921801A (en) * 1955-03-21 1960-01-19 Walter O Beyer Flexible pipe coupling
DE957704C (de) * 1955-03-23 1957-02-07 Ziefle Kg Eisenbau Albert Abdichtung fuer Rohrverbindungen
CH571678A5 (en) * 1974-09-09 1976-01-15 Meury Kurt Pipe or hose union - has clamping ring distorted into truncated cone on pulling up
US5720503A (en) * 1995-11-08 1998-02-24 Single Buoy Moorings Inc. Sealing sytem--anti collapse device
US6019137A (en) * 1996-01-11 2000-02-01 Coflexip Flexible pipe
WO1999019656A1 (fr) * 1997-10-14 1999-04-22 Nkt Flexibles I/S Ensemble constitue d'un tuyau souple et d'un raccord d'extremite

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008037274A1 (fr) * 2006-09-26 2008-04-03 Holger Knappe système de fermeture de la partie d'extrémité d'un tube ou d'un récipient tubulaire
US8141590B2 (en) 2006-09-26 2012-03-27 Holger Knappe Arrangement for sealing an end section of a tube or of a tubular vessel
WO2012110637A1 (fr) 2011-02-18 2012-08-23 Technip France Conduite tubulaire flexible pour le transport d'un fluide pétrolier tel qu'un fluide polyphasique ou un gaz.
WO2012126999A1 (fr) 2011-03-24 2012-09-27 Technip France Embout de connexion d'une conduite tubulaire flexible pour le transport d'un fluide en milieu marin et procédé de montage d'un tel embout de connexion
WO2014174244A1 (fr) * 2013-04-24 2014-10-30 Wellstream International Limited Élément de bague d'étanchéité
US10364925B2 (en) 2013-04-24 2019-07-30 Ge Oil & Gas Uk Limited Seal ring element
US11378207B2 (en) 2019-11-22 2022-07-05 Trinity Bay Equipment Holdings, LLC Swaged pipe fitting systems and methods

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