WO2016128626A1 - Annular packing material for a pipe with two tubes, device and pipe incorporating said packings and method for producing and assembling same - Google Patents

Annular packing material for a pipe with two tubes, device and pipe incorporating said packings and method for producing and assembling same Download PDF

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Publication number
WO2016128626A1
WO2016128626A1 PCT/FR2015/050363 FR2015050363W WO2016128626A1 WO 2016128626 A1 WO2016128626 A1 WO 2016128626A1 FR 2015050363 W FR2015050363 W FR 2015050363W WO 2016128626 A1 WO2016128626 A1 WO 2016128626A1
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WO
WIPO (PCT)
Prior art keywords
seal
flanges
axially
tubes
clamping
Prior art date
Application number
PCT/FR2015/050363
Other languages
French (fr)
Inventor
Marc Runfola
Original Assignee
Hutchinson
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.)
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Publication date
Application filed by Hutchinson filed Critical Hutchinson
Priority to PCT/FR2015/050363 priority Critical patent/WO2016128626A1/en
Publication of WO2016128626A1 publication Critical patent/WO2016128626A1/en

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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
    • F16L7/00—Supporting of pipes or cables inside other pipes or sleeves, e.g. for enabling pipes or cables to be inserted or withdrawn from under roads or railways without interruption of traffic
    • F16L7/02—Supporting of pipes or cables inside other pipes or sleeves, e.g. for enabling pipes or cables to be inserted or withdrawn from under roads or railways without interruption of traffic and sealing the pipes or cables inside the other pipes, cables or sleeves
    • 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
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/02—Sealings between relatively-stationary surfaces
    • F16J15/021—Sealings between relatively-stationary surfaces with elastic packing
    • F16J15/028—Sealings between relatively-stationary surfaces with elastic packing the packing being mechanically expanded against the sealing surface

Definitions

  • the present invention relates to an annular seal adapted to radially connect sealingly two concentric tubes to each other, a sealed device for mechanical connection between at least one pair of such concentric tubes of a pipe, such a pipeline in particular usable for transporting liquid or gaseous hydrocarbons and intended to be immersed in deep water, or for transporting water vapor in a district heating network, and a method of manufacturing and assembling such sealing gasket.
  • the invention thus applies in particular, but not exclusively, to an "offshore" double wall pipe carrying fluids whose temperature is different from that of the outer tubular wall of this pipe, in particular liquids or gases flowing through.
  • high temperature of the order of 95 ° C for example
  • the external temperature to the pipeline can be very low in the case of an underwater pipeline.
  • EP-B1-0 826 24 and EP-B1-0 932 795 teach to obtain a radial expansion of such joints by compressing them axially between two metal flanges bolted through the joint, by means of threaded rods passing through the joint from one side and tightened by nuts.
  • These flanges each consist of arcuate ring sectors which connect adjacent rod-nut pairs which are circumferentially spaced, thereby conferring on each flange a rigid discontinuous structure.
  • a major drawback of known seals lies in the rigid structure of these flanges compressing each seal, which does not always make it possible to obtain a sufficient degree of clamping of the seal in use, nor to control the minimum compressive force to be provided. depending on the thermal and mechanical stresses in use.
  • An object of the present invention is to provide an annular seal adapted to radially connect tightly two concentric tubes to one another which overcomes the aforementioned drawbacks, the seal comprising:
  • annular elastomeric sealing gasket having two axially opposite circumferential front faces
  • fastening means which fix the seal to said flanges by passing axially through the joint, and clamping means which are mounted axially outside said flange and which cooperate with said fixing means to exert an axial clamping force on the joint by said flanges.
  • a gasket according to the invention is such that it further comprises return means which recall said clamping means axially towards the gasket, so that said clamping force compensates for a thermal expansion of the gasket in operation while remaining substantially constant.
  • the seal of the gaskets according to the invention is thus guaranteed thanks to their durable expansion in use even in the event of large variations in the surrounding temperature because these return means, which are designed to be very insensitive to expansion thermal, oppose changes in the volume of the joint under the effect of its thermal expansion by maintaining this minimum clamping force.
  • said return means can be mounted axially between said one flange and said clamping means of which said flange is provided.
  • said fixing means may comprise threaded axial members such as tie-rods, which pass circumferentially through the seal circumferentially and each project axially from said one flange to an overlying portion receiving said means of rotation. clamping and said biasing means, none of said members protruding from the other said flange.
  • this non-opening fitting of the fastening means at the level of this other flange differs from the threaded rod opening out of the two flanges in the abovementioned documents, and that this partly non-opening fitting according to the invention provides a level of sealing superior to that of this prior art because the packing according to the invention is not traversed from one side by these fastening means.
  • said flanges may each advantageously have a continuous metal annular structure making them sufficiently flexible to control said clamping force, unlike the known rigid flanges formed of arcuate sectors used in these same documents.
  • 2n said fixing means, 2n said clamping means and 2n said return means can be mounted circumferentially spaced axially facing said front faces of the seal, so that said 2n biasing means respectively recall said 2n clamping means by constraining axially to said 2n fastening means.
  • said 2n biasing means may comprise compression-type springs preferably comprising a stack of spring washers, these springs being mounted radially. around said fastening means 2n and axiately in abutment between said one flange and n anti-rotation connection means that comprises the lining and which connect two by two between them said 2n fastening means provided with said 2n clamping means by opposing their rotation.
  • said n connecting means may each comprise a ring sector anti-rotation tab which is locked on a pair of said clamping means 2n, said clamping means each comprising a locking nut co-operating with a locking member. elastic fastening element, said fastening element such as a claw washer being mounted on said tab and angularly locking said nut.
  • each nut and each elastic fastening element provides an automatic mechanical lock that requires no external activation or manipulation and thus guarantees “blind” tightening with the integrated anti-loosening function.
  • said gasket may advantageously comprise an elastomeric outer coating layer which covers said flanges in said radially inner and outer axial faces and in said axially external radial face and which is intended to be mounted in contact with the tubes.
  • said elastomeric coating layer or film effectively protects said flanges from corrosion, and the tubes from repeated contact with said flanges.
  • this coating layer completely covers the flange where do not open said fixing means, thus preventing any infiltration of fluid or water between the flange and the inner and outer tubes.
  • this coating layer in direct contact with the metal flanges and the inner and outer tubes acts as a protective barrier, especially when these tubes are deformed significantly (especially by ovalization generated by bending of the pipe).
  • the inventors have indeed verified that the contact of the metal flanges on the tubes can generate fragilities (eg crack initiators) on the latter, which is incompatible with the expected lifetime on these pipes.
  • the lining may be obtained by overmolding the flanges, by injection into a mold and in contact with the flanges of a vulcanizable rubber composition intended to form the joint to obtain a composite.
  • molded comprising the vulcanized seal clamped by the flanges, said axially inner radial face of each of the suprapier flanges being coated with a bonding agent to adhere the flanges to said front faces of the joint by vulcanization of the injected composition.
  • a sealed mechanical connection device comprises at least one pair of radially inner and outer concentric tubes of a pipe which define between them an annular cross-sectional space, the device comprising annular thermally insulating mattresses filling said space and annular seals mounted in radial support against the inner and outer tubes and separating two so-called axially adjacent mats, is characterized in that each of the seals is as defined above.
  • a pipe according to the invention that can be used to transport liquid or gaseous hydrocarbons and intended to be immersed in water deep, or for transporting water vapor in a district heating network, the pipe comprising at least one pair of radially inner and outer concentric tubes which define between them an annular cross-sectional space, is characterized in that it comprises in said space a sealed connection device as defined above.
  • a manufacturing method and assembly according to the invention of a seal as defined above essentially comprises the following steps:
  • At least the flanges are covered with an elastomeric outer coating layer.
  • step a an axially inner circumferential radial face of each of the flanges of a bonding agent is coated to adhere the flanges to said front faces of the joint by vulcanizing the injected rubber composition.
  • the said clamping means positioned between the concentric tubes are tightened, the said clamping means each comprising a locking nut cooperating with an elastic fastening element; that a washer with claws angularly locking said nut, by maneuvering in a direction of tightening the nut by a drive key for example dynamometer terminating in a clamping sleeve of said nut, and optionally
  • FIG. 1a is a partial diagrammatic view in axial section of a double wall pipe section according to the invention
  • FIG. 1b is a partial diagrammatic view in axial section of a pipe section such as that of FIG. 1 showing the effects of accidental perforation of the outer tube of this section,
  • FIG. 2a is a diagrammatic view in axial section of a seal according to the invention that can be used in this section, shown in a rest position where the seal is not compressed,
  • FIG. 2b is a diagrammatic view in axial section of the lining of FIG. 2a in a position where the seal is compressed
  • FIG. 3 is a rear side view of a seal according to an example of the invention similar to that of FIGS. 1 a and 2b,
  • FIG. 4 is a rear perspective view of the seal of FIG. 3,
  • FIG. 5 is a partial axial half-sectional view of the seal of FIGS. 3 and 4 along the plane VV of FIG. 3;
  • FIG. 6 is a partially exploded rear perspective view of this seal such as shown in the assembled view in Figure 4,
  • FIG. 7 is an exploded perspective detail view of the medallion of FIG. 6 showing assembled elements,
  • FIG. 8 is a perspective view of a molded composite according to the invention from which the packing of FIGS. 3-7 has been obtained
  • FIG. 9 is a perspective view of a fastening means according to an example of FIG. 'invention
  • FIG. 10 is a perspective view of an anti-rotation connection means according to an example of the invention for locking the clamping means
  • FIG. 11 is a perspective view of a bearing washer according to an example of the invention that can be used between the flange provided with the clamping means and the return means,
  • FIG. 12 is a perspective view of an elastic fastening element according to an example of the invention cooperating with the connecting means of FIG. 10 and with the clamping means of FIG. 13,
  • FIG. 13 is a view in perspective of a clamping means according to an example of the invention cooperating with the fastening element of FIG. 12 via the connecting means of FIG. 10,
  • FIG. 14 is a view in axial section of an elastic washer according to an example of the invention that can be used in the recall means,
  • FIG. 15 is a schematic view in axial section of a pipe section according to the invention incorporating a seal according to the invention, showing the step of clamping this packing
  • FIG. 16 is a partial side view of a seal according to the invention being tightened, such as that of FIGS. 3-6, more clearly illustrating this clamping step
  • FIGS. 3-6 more clearly illustrating this clamping step
  • Figures 17a, 17b and 17c are partial side views of the seal of Figure 16, respectively showing three successive phases of the loosening step of this liner.
  • axial and axially refer to a direction parallel to the longitudinal axis of symmetry X of the pipes which is coincident with that of the seals
  • radial and “radiaiement” refer to a direction or a plane transverse to this axis X which contains for a symmetry of revolution all the directions perpendicular to this axis.
  • a double-walled pipe 1 according to the invention is particularly suitable for transporting liquid or gaseous fluids whose transport temperature is very different from that of the outer wall of pipe 1 located in contact with the ambient environment, for example in deep water in which it is disposed,
  • the pipe 1 comprises a succession of straight cylindrical sections 2 which are optionally interconnected by at least one bent section and which have a cross section for example circular.
  • Each section 2 essentially comprises:
  • annular packing 5 between the inner and outer tubes 4, which comprises thermally insulating mats 6 mounted radially in contact with the tubes 3 and 4 and separated axially in pairs from each other by annular seals 7 according to the invention .
  • Each lining 7 is intended in the first place to mechanically and flexibly fasten the tube 3 to the tube 4, and to further ensure a sealing function to allow proper operation in degraded mode of the pipe 1.
  • This mode operation gradient is illustrated in Figure 1b, which shows a case of breach or accidental perforation 4a of the outer tube 4 having generated a water inlet in an annular compartment 6a filled with one of the mattresses 6, and requires that each pad 7 preserves precisely and durably its axial and radial position between the tubes 3 and 4 by sealingly confining the water having entered this compartment 6a so as not to flood the contiguous annular compartments, in spite of its difference existing between the pressure Pa of the non-flooded thermally insulating compartments 6 substantially at atmospheric pressure and compartment pressure Pw thermally insulating intermediate 6a filled with water (being substantially at the same pressure as the surrounding water).
  • each seal 7 essentially comprises:
  • a solid annular elastomeric sealing gasket 8 having two circumferential front faces axially front 8a and rear 8b in the form of radial circular rings,
  • FIGS. 6 and 9 a plurality of axial threaded cylindrical tie rods 10 (see FIGS. 6 and 9) regularly spaced in the circumferential direction axially crossing the gasket 8 and the perforations 9c of the flanges 9a and 9b to fix the gasket 8 to the latter and protruding axially of the only rear flange 9b (by convention, that mounted to the right of the gasket 8 in FIGS. 2a, 2b and 5 and to the left of the gasket 8 in FIGS. 4 and 6),
  • each spring 15 which is of compression type being adapted to oppose the effects of the axial stresses on the tie rods 10 generated by the thermal expansion of the gasket 8 in operation, to permanently obtain a minimum clamping of the gasket 8 via the axial return of the nuts 12 to the rear face 8b of the seal 8 (ia Figure 5 shows the direction of this force F return).
  • the seal 8 is obtained by overmoulding in contact with the flanges 9a and 9b provided with their respective perforations 9c, it being specified that this seal 8 is molded without being provided with the tie rods 10 nor its "deck hardware" (including the clamping means 11 and the springs 15) to obtain the molded composite 6 shown in Fig. 8, as explained hereinafter.
  • the front flanges 9a and rear 9b are previously coated with an adhesive coating ("primer" in English) at their axially internal radial faces 9ad and 9bd and are secured by overmolding to the respective front faces 8a and 8b of the gasket 8 following the vulcanization of the latter in a mold, to obtain a satisfactory adhesion and cohesion between the vulcanized rubber composition of the molded gasket 8 and the metal material of the flanges 9a and 9b.
  • an adhesive coating ("primer" in English)
  • the flanges 9a and 9b thus adhered to the mold are firmly positioned in the manner of over-molding inserts, and then the mold is closed so as to trap the flanges 9a and 9b therein and then injecting under high pressure and at high temperature the vulcanizable rubber composition intended to form the seal 8. It is the combination of pressure, temperature and vulcanization time which confers both the desired elastic properties at the joint 8 and ensures the irreversible cohesion vulcanized rubber of the gasket 8 on the metal of the flanges 9a and 9b.
  • a seal 7 according to the invention furthermore comprises: a multitude of metal plugs 17 which are applied for example by crimping against the axially outer face 9ac of the front flange 9a (ie the flange from which the tie rods 10 do not open) so as to plug the respective perforations 9c of this flange 9a,
  • an elastomeric outer coating layer 19 which completely covers the gasket 8 and the external faces of the flanges 9a and 9b by being applied, on the one hand, to their radially inner circumferential axial faces 9aa, 9ba and external 9ab, 9bb so that to be mounted in contact with the tubes 3 and 4 (the layer 19 forming an anti-corrosion barrier for each lining 7 and protecting the tubes 3 and 4 from premature wear or cracking by contact) and, on the other hand, on the axially external radial faces 9ac and 9bc of the flanges 9a and 9b.
  • each pair of springs 15 forms a compensating expansion block with:
  • each pair of springs 15 support and which has two orifices 14 'respectively receiving two tie rods 10, and
  • a minimum tightening of the gasket 8 must be provided at low temperature, for example around 0 ° C, especially in the case of a pipe immersed in deep water.
  • the gasket 8 is almost entirely confined and the elastomer constituting it can be considered to be substantially incompressible, the effects of positive thermal expansion, in particular at high fluid transport temperature (for example around 95.degree. very high pressures on the walls of the tubes 3 and 4 which ultimately induce additional tensile stresses on the tie rods 10.
  • the aforementioned expansion compensating blocks incorporating the springs 15 guarantee a minimum tightening of the gasket 8 at low temperature and limit the stresses in the tie rods 10 at high temperature, it being specified that the stiffness of the springs 15 is defined to attenuate the variations of forces due to variations in distance due to this expansion of the gasket 8 between the initial position of the nuts 12 and the bearing surfaces of the springs 15 constituted by the washers 18 applied to the rear flange 9b.
  • each nut 12 by its specific form, is locked in rotation by the washer 13 in the loosening direction, by indexing in rotation every 72 ° (ie a fifth of a turn) in this embodiment with five locking claws 13a.
  • This automatic mechanical blocking has the advantage of not requiring any external activation or manipulation, thanks to the particular shape and elasticity of the claws 13a which allow their natural positioning on a locking profii 12a of each nut 12 by creating a mechanical obstacle opposing its loosening (which guarantees a reliable and "blind” tightening).
  • this locking profile 12a of each nut 12 overcomes these sections 12b and has five identical convexly curved surfaces 12c with an external radiating tip 12d which are regularly arranged on the circumference of the profile 12a and which are connected two to two of them by a recess 12e formed between each point 12d and the birth of the curved surface 12c adjacent.
  • each compensating spring 15 has a generally radial geometry within their stack once mounted around the tie rod 10 corresponding, but we see in Figure 14 that each spring washer 15a, for example steel, actually has a flared wall of convergent frustoconical shape with, for example, the following dimensional characteristics (non-limiting data):
  • FIGS. 2a and 2b illustrate the radial expansion of each gasket 7 inserted between the two tubes 3 and 4 of a section 2 of pipe 1.
  • the annular seal 8 must of course have at rest dimensions smaller than the minimum radial dimension between the tubes 3 and 4, taking into account the manufacturing tolerances of the latter.
  • the seal 8 is axially compressed by the approximation of the flanges 9a and 9b that is obtained by tightening the self-locking nuts 12 on the threaded tie rods 10 on which they are respectively mounted, which causes the radial swelling the seal 8 which is progressively flattened radially against the two tubes 3 and 4. After this contact, the tightening is continued until reaching the target torque which ensures a contact pressure on the two tubes 3 and 4 provided sufficient to withstand the pressure differences Pa and Pw between the annular compartments (see again Figure 1 b).
  • the thickness W 1 of the compressed gasket 8 and the internal diameters ID 1 and external OD 1 of the compressed gasket 8 which respectively correspond to the external diameter of the inner tube 3 and to the internal diameter of the outer tube 4.
  • FIGS. 15 and 16 illustrate the assembly and tightening of the gasket 8.
  • the seal 8 is axially slid axially without significant effort (i.e. without specific heavy tools) between the two tubes 3 and 4 thanks to its adapted dimensions which vary according to its state of compression.
  • each nut 12 is used to tighten a torque-type compact clamping system 21 which terminates in a standard drive bushing 22 and which can pass through. easily between the tubes 3 and 4.
  • these self-locking nuts 12 allow, in relation to the washers 13 with claws 13a, to maintain the initial tightening of the flanges 9a and 9b reliably and perennially.
  • the washers 13 with claws 13a do not prevent the rotation of the nuts 12 in the clockwise direction A of the clamping and lock respectively the nuts 12 at each rotation of 72 ° in this example shown.
  • the present invention has provided for this purpose the possibility of loosening the nuts 12 self-locking without damaging them.
  • a specific drive bushing 23 is used for loosening which is different from the standard clamping bush 22 and which makes it possible to unlock and loosen the nuts 12 in the same manner. without first having to maneuver directly these nuts 12. It is inserted first a douile 23 in the annular space between the tubes 3 and 4 in the axial direction P ( Figure 17a), then makes it come into contact with the claws 13a of each washer 13 (FIG.
  • the tightening / loosening system 20-23 according to the invention of the nuts 12 via the washers 13 with claws 13a can be advantageously used in any mechanical application requiring a secure clamping, and where the operation tightening / loosening must be carried out with reduced access to the only passage of a clamping tool.

Abstract

The invention relates to an annular packing seal for producing a sealed link between two mutually concentric tubes, a sealed device for a mechanical link between the tubes of a pipe, said pipe and a method for producing and assembling such a packing. Said packing seal (7) comprises: an annularly sealing elastomer seal (8) having two axially opposed circumferential front faces, two flanges (9a and 9b) which respectively grip said front faces by compressing the axial seal in such a way that said seal is radially expanded by pressing against the tubes, attachment means (10) attaching the seal to the flanges by passing therethrough, and tightening means (11) which are axially mounted on the exterior of said flange (9b) and which engage with said attachment means in order for the flanges to exert an axial tightening force on the seal. According to the invention, the packing comprises return means (15) which return the tightening means towards the seal, such that the tightening force offsets a dilation of the seal while remaining substantially constant.

Description

GARNITURE D'ETANCHEITE ANNULAIRE POUR CANALISATION A DEUX TUBES, DISPOSITIF ET CANALISATION INCORPORANT CES GARNITURES ET LEUR PROCEDE DE FABRICATION/ASSEMBLAGE. La présente invention concerne une garniture d'étanchéité annuiaire adaptée pour relier radiaiement de manière étanche deux tubes concentriques l'un à l'autre, un dispositif étanche de liaison mécanique entre au moins une paire de tels tubes concentriques d'une canalisation, une telle canalisation en particulier utilisable pour transporter des hydrocarbures liquides ou gazeux et destinée à être immergée en eau profonde, ou bien pour transporter de la vapeur d'eau dans un réseau de chauffage urbain, et un procédé de fabrication et d'assemblage d'une telle garniture d'étanchéité. L'invention s'applique ainsi notamment, mais pas exclusivement, à une canalisation « offshore » à double paroi transportant des fluides dont la température est différente de celle de la paroi tubulaire extérieure de cette canalisation, en particulier des liquides ou des gaz circulant à haute température (de l'ordre de 95° C par exemple) à l'intérieur de la paroi tubulaire interne, par contraste avec la température externe à la canalisation pouvant être très basse dans le cas d'une canalisation sous-marine.  ANNULAR SEAL PIPE FOR TWO TUBES PIPE, DEVICE AND PIPE INCORPORATING THESE PACKINGS AND METHOD OF MANUFACTURING / ASSEMBLING THE SAME. The present invention relates to an annular seal adapted to radially connect sealingly two concentric tubes to each other, a sealed device for mechanical connection between at least one pair of such concentric tubes of a pipe, such a pipeline in particular usable for transporting liquid or gaseous hydrocarbons and intended to be immersed in deep water, or for transporting water vapor in a district heating network, and a method of manufacturing and assembling such sealing gasket. The invention thus applies in particular, but not exclusively, to an "offshore" double wall pipe carrying fluids whose temperature is different from that of the outer tubular wall of this pipe, in particular liquids or gases flowing through. high temperature (of the order of 95 ° C for example) inside the inner tubular wall, in contrast with the external temperature to the pipeline can be very low in the case of an underwater pipeline.
D'une manière générale il est connu de relier mécaniquement, par des garnitures d'étanchéité annulaires incorporant chacune un joint élastomère expansible et intercalées axialement entre des matelas thermiquement isolants, deux tubes concentriques formant une double paroi d'une canalisation « offshore » immergée transportant à l'intérieur du tube interne un hydrocarbure liquide ou gazeux à haute température. Une fonction principale de ces garnitures est de solidariser mécaniquement et de manière souple le tube interne avec le tube externe, étant précisé que l'on recherche en outre l'étanchéité de cette jonction en assurant un fonctionnement en mode dégradé de la canalisation en cas de perforation de i'un des deux tubes, notamment, comme expliqué ci-après.  In general it is known to mechanically connect, by annular seals each incorporating an expandable elastomeric seal and interposed axially between thermally insulating mats, two concentric tubes forming a double wall of a submerged "offshore" pipeline carrying inside the inner tube a hydrocarbon liquid or gaseous at high temperature. A main function of these gaskets is to mechanically and flexibly fasten the inner tube to the outer tube, it being specified that the sealing of this junction is also sought by ensuring degraded operation of the pipe in the event of perforation of one of the two tubes, in particular, as explained below.
On peut citer à ce titre les documents EP-B1-0 826 24 et EP-B1-0 932 795 qui enseignent d'obtenir une expansion radiale de tels joints en les comprimant axialement entre deux brides métalliques boulonnées à travers ie joint, au moyen de tiges filetées traversant ie joint de part en part et serrées par des écrous. Ces brides sont chacune constituées de secteurs d'anneau en arcs de cercle qui relient des paires tiges-écrous adjacentes et qui sont circonférentiellement espacés, conférant ainsi à chaque bride une structure discontinue rigide. Examples of this are EP-B1-0 826 24 and EP-B1-0 932 795, which teach to obtain a radial expansion of such joints by compressing them axially between two metal flanges bolted through the joint, by means of threaded rods passing through the joint from one side and tightened by nuts. These flanges each consist of arcuate ring sectors which connect adjacent rod-nut pairs which are circumferentially spaced, thereby conferring on each flange a rigid discontinuous structure.
Un inconvénient majeur des garnitures d'étanchéité connues réside dans la structure rigide de ces brides comprimant chaque joint, qui ne permet pas toujours d'obtenir un degré de serrage suffisant du joint en service, ni de contrôler l'effort de compression minimal à fournir en fonction des contraintes thermiques et mécaniques en utilisation.  A major drawback of known seals lies in the rigid structure of these flanges compressing each seal, which does not always make it possible to obtain a sufficient degree of clamping of the seal in use, nor to control the minimum compressive force to be provided. depending on the thermal and mechanical stresses in use.
Un autre inconvénient des garnitures d'étanchéité connues pouvant découler du précédent réside dans l'expansion radiale de ces joints qui peut s'avérer insuffisante en service pour cloisonner de manière étanche les compartiments annulaires thermiquement isolants agencés axialement de part et d'autre de ces garnitures, en cas d'infiltration d'eau dans l'un de ces compartiments suite à une perforation accidentelle du tube interne ou externe le délimitant, de sorte à éviter l'inondation du compartiment voisin par un défaut d'étanchéité du joint.  Another disadvantage of the known seals that may arise from the previous lies in the radial expansion of these seals which may be insufficient in use to partition sealingly the annular heat-insulating compartments arranged axially on either side of these seals, in case of water infiltration into one of these compartments following an accidental perforation of the inner or outer tube delimiting it, so as to avoid flooding of the neighboring compartment by a seal leakage.
Un but de la présente invention est de proposer une garniture d'étanchéité annulaire adaptée pour relier radiaiement de manière étanche deux tubes concentriques l'un à l'autre qui remédie notamment aux inconvénients précités, la garniture comprenant :  An object of the present invention is to provide an annular seal adapted to radially connect tightly two concentric tubes to one another which overcomes the aforementioned drawbacks, the seal comprising:
- un joint élastomère d'étanchéité annulaire présentant deux faces frontales circonférentielles axialement opposées,  an annular elastomeric sealing gasket having two axially opposite circumferential front faces,
- deux brides qui enserrent respectivement lesdites faces frontales en comprimant axialement le joint de sorte qu'il soit expansé radiaiement en appuyant contre lesdits tubes,  two flanges which enclose respectively said front faces by compressing the gasket axially so that it is radially expanded by pressing against said tubes,
- des moyens de fixation qui fixent le joint auxdites brides en traversant axialement le joint, et - des moyens de serrage qui sont montés axialement à l'extérieur d'une dite bride et qui coopèrent avec iesdits moyens de fixation pour exercer un effort de serrage axial sur le joint par iesdites brides. fastening means which fix the seal to said flanges by passing axially through the joint, and clamping means which are mounted axially outside said flange and which cooperate with said fixing means to exert an axial clamping force on the joint by said flanges.
A cet effet, une garniture selon l'invention est telle qu'elle comprend en outre des moyens de rappel qui rappellent Iesdits moyens de serrage axialement vers le joint, de sorte que ledit effort de serrage compense une dilatation thermique du joint en fonctionnement en demeurant sensiblement constant.  For this purpose, a gasket according to the invention is such that it further comprises return means which recall said clamping means axially towards the gasket, so that said clamping force compensates for a thermal expansion of the gasket in operation while remaining substantially constant.
On notera que ces moyens de rappel permettent de contrebalancer les effets générés par la dilatation thermique positive du joint au contact du fluide qui est usueliement transporté à près de 00° C dans le cas d'un hydrocarbure, en s'opposant aux contraintes axiales sur Iesdits moyens de fixation qui sont générées par cette dilatation et en garantissant ainsi l'étanchéité de la garniture en utilisation.  It will be noted that these return means make it possible to counterbalance the effects generated by the positive thermal expansion of the seal in contact with the fluid which is usually transported at close to 00 ° C. in the case of a hydrocarbon, by opposing the axial stresses on Said fixing means which are generated by this expansion and thus ensuring the sealing of the lining in use.
Avantageusement, l'étanchéité des garnitures selon l'invention est ainsi garantie grâce à leur expansion pérenne en utilisation même en cas de grandes variations de la température environnante du fait que ces moyens de rappel, qui sont conçus pour être très peu sensibles à la dilatation thermique, s'opposent aux variations de volume du joint sous l'effet de sa dilatation thermique par le maintien de cet effort minimum de serrage.  Advantageously, the seal of the gaskets according to the invention is thus guaranteed thanks to their durable expansion in use even in the event of large variations in the surrounding temperature because these return means, which are designed to be very insensitive to expansion thermal, oppose changes in the volume of the joint under the effect of its thermal expansion by maintaining this minimum clamping force.
On notera également que ce serrage et cette expansion optimisés des garnitures selon l'invention permettent de confiner efficacement l'eau ayant pénétré dans un compartiment thermiquement isolant par perforation accidentelle du tube interne ou externe, en rendant ainsi ce compartiment inondé étanche vis-à-vis des compartiments thermiquement isolants contigus.  It will also be noted that this optimized clamping and expansion of the gaskets according to the invention makes it possible to effectively confine the water having penetrated into a thermally insulating compartment by accidental perforation of the inner or outer tube, thus making this compartment flooded with watertightness. screw contiguous thermally insulating compartments.
Selon une autre caractéristique de l'invention, iesdits moyens de rappel peuvent être montés axialement entre ladite une bride et Iesdits moyens de serrage dont cette bride est pourvue.  According to another characteristic of the invention, said return means can be mounted axially between said one flange and said clamping means of which said flange is provided.
On notera que le rapprochement par l'effort de serrage précité des deux brides formant armature pour le joint est ainsi contrôlé par ces moyens de rappei, dont la raideur peut être ajustée en fonction du degré de serrage minimal souhaité. It will be noted that the bringing together by the aforementioned clamping force of the two reinforcing flanges for the joint is thus controlled by these means of rappei, the stiffness of which can be adjusted according to the desired minimum degree of clamping.
Selon une autre caractéristique de l'invention, lesdits moyens de fixation peuvent comprendre des organes axiaux filetés tels que des tirants, qui traversent le joint de manière circonférentiellement espacée et qui dépassent chacun axialement de ladite une bride en une portion de dépassement recevant lesdits moyens de serrage et lesdits moyens de rappel, aucun desdits organes ne dépassant de l'autre dite bride.  According to another characteristic of the invention, said fixing means may comprise threaded axial members such as tie-rods, which pass circumferentially through the seal circumferentially and each project axially from said one flange to an overlying portion receiving said means of rotation. clamping and said biasing means, none of said members protruding from the other said flange.
On notera que ce montage non débouchant des moyens de fixation au niveau de cette autre bride se distingue de la tige filetée débouchant hors des deux brides dans les documents précités, et que ce montage en partie non débouchant selon l'invention procure un niveau d'étanchéité supérieur à celui de cet art antérieur du fait que la garniture selon l'invention n'est pas traversée de part en part par ces moyens de fixation.  It will be noted that this non-opening fitting of the fastening means at the level of this other flange differs from the threaded rod opening out of the two flanges in the abovementioned documents, and that this partly non-opening fitting according to the invention provides a level of sealing superior to that of this prior art because the packing according to the invention is not traversed from one side by these fastening means.
Selon une autre caractéristique de l'invention, lesdites brides peuvent présenter chacune avantageusement une structure annulaire métallique continue les rendant suffisamment flexibles pour contrôler ledit effort de serrage, contrairement aux brides rigides connues formées de secteurs en arcs de cercle utilisées dans ces mêmes documents.  According to another characteristic of the invention, said flanges may each advantageously have a continuous metal annular structure making them sufficiently flexible to control said clamping force, unlike the known rigid flanges formed of arcuate sectors used in these same documents.
On notera que cette flexibilité des brides continues selon l'invention peut être ajustée en fonction de i'effort de compression axiale du joint à fournir en utilisation.  It will be noted that this flexibility of the continuous flanges according to the invention can be adjusted as a function of the axial compression force of the gasket to be provided in use.
Selon une autre caractéristique de l'invention, 2n dits moyens de fixation, 2n dits moyens de serrage et 2n dits moyens de rappel (n entier naturel égal ou supérieur à 2 et de préférence égal ou supérieur à 4) peuvent être montés de manière circonférentiellement espacée axialement en regard desdites faces frontales du joint, de sorte que lesdits 2n moyens de rappel rappellent respectivement lesdits 2n moyens de serrage en les contraignant axialement vers lesdits 2n moyens de fixation.  According to another characteristic of the invention, 2n said fixing means, 2n said clamping means and 2n said return means (n natural integer equal to or greater than 2 and preferably equal to or greater than 4) can be mounted circumferentially spaced axially facing said front faces of the seal, so that said 2n biasing means respectively recall said 2n clamping means by constraining axially to said 2n fastening means.
Avantageusement, lesdits 2n moyens de rappel peuvent comprendre des ressorts de type à compression comportant de préférence un empilement de rondelles élastiques, ces ressorts étant montés radiaiement autour desdits 2n moyens de fixation et axiaiement en appui entre ladite une bride et n moyens de liaison anti-rotation que comprend la garniture et qui relient deux à deux entre eux lesdits 2n moyens de fixation pourvus desdits 2n moyens de serrage en s'opposant à leur rotation. Advantageously, said 2n biasing means may comprise compression-type springs preferably comprising a stack of spring washers, these springs being mounted radially. around said fastening means 2n and axiately in abutment between said one flange and n anti-rotation connection means that comprises the lining and which connect two by two between them said 2n fastening means provided with said 2n clamping means by opposing their rotation.
Encore plus avantageusement, lesdits n moyens de liaison peuvent comprendre chacun une patte anti-rotation en forme de secteur d'anneau qui est verrouillée sur une paire desdits 2n moyens de serrage, lesdits 2n moyens de serrage comprenant chacun un écrou de verrouillage coopérant avec un élément d'accrochage élastique, ledit élément d'accrochage tel qu'une rondelle à griffes étant monté sur une dite patte et verrouillant angulairement ledit écrou.  Even more advantageously, said n connecting means may each comprise a ring sector anti-rotation tab which is locked on a pair of said clamping means 2n, said clamping means each comprising a locking nut co-operating with a locking member. elastic fastening element, said fastening element such as a claw washer being mounted on said tab and angularly locking said nut.
On notera que la coopération entre chaque écrou et chaque élément d'accrochage élastique procure un blocage mécanique automatique qui ne requiert aucune activation externe ni manipulation et qui garantit ainsi un serrage « en aveugle » avec la fonction d'anti-desserrage intégrée.  It should be noted that the cooperation between each nut and each elastic fastening element provides an automatic mechanical lock that requires no external activation or manipulation and thus guarantees "blind" tightening with the integrated anti-loosening function.
Selon une autre caractéristique de l'invention, lesdites brides présentant chacune une face axiale circonférentielie radiaiement externe, une face axiale circonférentielie radiaiement interne, une face radiale circonférentielie axiaiement externe et une face radiale circonférentielie axiaiement interne en contact avec le joint, la garniture peut avantageusement comporter une couche d'enrobage externe élastomère qui recouvre lesdites brides en lesdites faces axiales radiaiement interne et externe et en ladite face radiale axiaiement externe et qui est destinée à être montée au contact des tubes.  According to another characteristic of the invention, said flanges each having a radially outer circumferential axial face, a radially inner circumferential axial face, an axially external circumferential radial face and an axially internal radial circumferential face in contact with the gasket, the gasket may advantageously comprise an elastomeric outer coating layer which covers said flanges in said radially inner and outer axial faces and in said axially external radial face and which is intended to be mounted in contact with the tubes.
On notera que ladite couche ou film d'enrobage élastomère protège efficacement lesdites brides de la corrosion, et les tubes du contact répété avec lesdites brides. En particulier, cette couche d'enrobage recouvre intégralement la bride où ne débouchent pas lesdits moyens de fixation, faisant ainsi obstacle à toute infiltration de fluide ou d'eau entre cette bride et les tubes interne et externe.  Note that said elastomeric coating layer or film effectively protects said flanges from corrosion, and the tubes from repeated contact with said flanges. In particular, this coating layer completely covers the flange where do not open said fixing means, thus preventing any infiltration of fluid or water between the flange and the inner and outer tubes.
Avantageusement, cette couche d'enrobage en contact direct avec les brides métalliques et les tubes interne et externe fait office de barrière de protection, notamment lorsque ces tubes se déforment de façon importante (en particulier par une ovaiisation générée par un cintrage de la canalisation). Les inventeurs ont en effet vérifié que le contact des brides métalliques sur les tubes peut générer des fragilités (e.g. des amorces de fissures) sur ces derniers, ce qui est incompatibie avec la durée de vie attendue sur ces canalisations. Advantageously, this coating layer in direct contact with the metal flanges and the inner and outer tubes acts as a protective barrier, especially when these tubes are deformed significantly (especially by ovalization generated by bending of the pipe). The inventors have indeed verified that the contact of the metal flanges on the tubes can generate fragilities (eg crack initiators) on the latter, which is incompatible with the expected lifetime on these pipes.
Selon un autre aspect de l'invention, la garniture peut être obtenue par un surmoulage des brides, par injection dans un moule et au contact des brides d'une composition de caoutchouc vulcanisable destinée à constituer le joint pour l'obtention d'un composite moulé comprenant ie joint vulcanisé enserré par les brides, ladite face radiale axialement interne de chacune des brides à surmouier étant revêtue d'un agent d'adhérisation pour faire adhérer les brides auxdites faces frontales du joint par vulcanisation de la composition injectée.  According to another aspect of the invention, the lining may be obtained by overmolding the flanges, by injection into a mold and in contact with the flanges of a vulcanizable rubber composition intended to form the joint to obtain a composite. molded comprising the vulcanized seal clamped by the flanges, said axially inner radial face of each of the suprapier flanges being coated with a bonding agent to adhere the flanges to said front faces of the joint by vulcanization of the injected composition.
On notera que cette adhésion entre le caoutchouc du joint et le matériau métallique des brides se distingue du simple contact enseigné par les documents précités de l'art antérieur, en garantissant une étanchéité parfaite entre ces brides et le joint.  Note that this adhesion between the seal rubber and the metal material of the flanges differs from the simple contact taught by the aforementioned documents of the prior art, ensuring a perfect seal between these flanges and the seal.
Un dispositif étanche de liaison mécanique selon l'invention entre au moins une paire de tubes concentriques radialement interne et externe d'une canalisation qui définissent entre eux un espace de section transversale annulaire, le dispositif comprenant des matelas annulaires thermiquement isolants remplissant ledit espace et des garnitures d'étanchéité annulaires montées en appui radial contre les tubes interne et externe et séparant deux dits matelas axialement adjacents, est caractérisé en ce que chacune des garnitures d'étanchéité est telle que définie ci-dessus.  A sealed mechanical connection device according to the invention comprises at least one pair of radially inner and outer concentric tubes of a pipe which define between them an annular cross-sectional space, the device comprising annular thermally insulating mattresses filling said space and annular seals mounted in radial support against the inner and outer tubes and separating two so-called axially adjacent mats, is characterized in that each of the seals is as defined above.
On notera que l'on peut utiliser pour ces matelas tout matériau connu pour ses propriétés thermiquement isolantes dans des canalisations à double paroi présentant en service le fort gradient de température précité entre les tubes interne et externe.  Note that one can use for these mattresses any material known for its thermally insulating properties in double wall pipes having in service the strong temperature gradient above between the inner and outer tubes.
Une canalisation selon l'invention utilisable pour transporter des hydrocarbures liquides ou gazeux et destinée à être immergée en eau profonde, ou bien pour transporter de la vapeur d'eau dans un réseau de chauffage urbain, la canalisation comprenant au moins une paire de tubes concentriques radialement interne et externe qui définissent entre eux un espace de section transversale annulaire, est caractérisée en ce qu'elle comprend dans ledit espace un dispositif étanche de liaison tel que défini ci- dessus. A pipe according to the invention that can be used to transport liquid or gaseous hydrocarbons and intended to be immersed in water deep, or for transporting water vapor in a district heating network, the pipe comprising at least one pair of radially inner and outer concentric tubes which define between them an annular cross-sectional space, is characterized in that it comprises in said space a sealed connection device as defined above.
Un procédé de fabrication et d'assemblage selon l'invention d'une garniture d'étanchéité telle que définie ci-dessus comprend essentiellement les étapes suivantes :  A manufacturing method and assembly according to the invention of a seal as defined above essentially comprises the following steps:
a) un surmoulage desdites brides annulaires qui sont avantageusement continues, par injection dans un moule et au contact des brides d'une composition de caoutchouc vuicanisable destinée à constituer le joint, pour l'obtention d'un composite moulé comprenant le joint vulcanisé enserré par les brides,  a) overmoulding of said annular flanges which are advantageously continuous, by injection into a mold and in contact with the flanges of a vuicizable rubber composition intended to constitute the seal, for obtaining a molded composite comprising the vulcanized gasket enclosed by the flanges,
b) un montage desdits moyens de fixation, tels que des organes filetés de type tirants, axiaîement à travers ce composite moulé, et c) un montage desdits moyens de serrage, tels que Iesdits écrous coopérant respectivement avec iesdites rondelles à griffes via lesdites pattes anti-rotation, sur Iesdits moyens de fixation par l'intermédiaire desdits moyens de rappel.  b) an assembly of said fastening means, such as threaded members of the tie-rod type, axially through this molded composite, and c) an assembly of said clamping means, such that said nuts cooperating respectively with said claw washers via said anti-lock tabs; -rotation on said fixing means via said biasing means.
De préférence, on recouvre en outre au moins les brides d'une couche d'enrobage externe élastomère.  Preferably, at least the flanges are covered with an elastomeric outer coating layer.
Avantageusement, on revêt avant l'étape a) une face radiale circonférentielie axiaîement interne de chacune des brides d'un agent d'adhérisation pour faire adhérer les brides auxdites faces frontales du joint par vulcanisation de la composition de caoutchouc injectée.  Advantageously, prior to step a), an axially inner circumferential radial face of each of the flanges of a bonding agent is coated to adhere the flanges to said front faces of the joint by vulcanizing the injected rubber composition.
Selon un autre aspect de l'invention, après l'étape c) :  According to another aspect of the invention, after step c):
- on serre Iesdits moyens de serrage positionnés entre les tubes concentriques, Iesdits moyens de serrage comprenant chacun un écrou de verrouillage coopérant avec un élément d'accrochage élastique te! qu'une rondelle à griffes verrouillant angulairement ledit écrou, en manœuvrant dans un sens de serrage l'écrou par une clef d'entraînement par exemple dynamométrique se terminant par une douille de serrage dudit écrou, et optionnellement the said clamping means positioned between the concentric tubes are tightened, the said clamping means each comprising a locking nut cooperating with an elastic fastening element; that a washer with claws angularly locking said nut, by maneuvering in a direction of tightening the nut by a drive key for example dynamometer terminating in a clamping sleeve of said nut, and optionally
- on desserre lesdits moyens de serrage positionnés entre lesdits tubes concentriques, en manœuvrant uniquement ledit élément d'accrochage élastique dans un sens inverse de desserrage de manière à décrocher ledit élément d'accrochage dudit écrou.  - Unclamping said clamping means positioned between said concentric tubes, by operating only said elastic fastening element in a reverse loosening direction so as to disengage said fastening element of said nut.
D'autres caractéristiques, avantages et détails de la présente invention ressortiront à la lecture de la description suivante d'un exemple de réalisation de l'invention, donné à titre iilustratif et non limitatif, la description étant réalisée en référence aux dessins joints, parmi lesquels :  Other features, advantages and details of the present invention will emerge on reading the following description of an exemplary embodiment of the invention, given for illustrative and nonlimiting purposes, the description being made with reference to the accompanying drawings, among which :
la figure 1 a est une vue schématique partielle en section axiale d'un tronçon de canalisation à double paroi selon l'invention,  FIG. 1a is a partial diagrammatic view in axial section of a double wall pipe section according to the invention,
la figure 1 b est une vue schématique partielle en section axiale d'un tronçon de canalisation tei que celui de la figure 1 montrant les effets d'une perforation accidentelle du tube externe de ce tronçon,  FIG. 1b is a partial diagrammatic view in axial section of a pipe section such as that of FIG. 1 showing the effects of accidental perforation of the outer tube of this section,
la figure 2a est une vue schématique en coupe axiale d'une garniture d'étanchéité selon l'invention utilisable dans ce tronçon, montrée dans une position de repos où le joint n'est pas comprimé,  FIG. 2a is a diagrammatic view in axial section of a seal according to the invention that can be used in this section, shown in a rest position where the seal is not compressed,
la figure 2b est une vue schématique en coupe axiale de ia garniture de la figure 2a dans une position où le joint est comprimé,  FIG. 2b is a diagrammatic view in axial section of the lining of FIG. 2a in a position where the seal is compressed,
la figure 3 est une vue latérale arrière d'une garniture d'étanchéité selon un exemple de l'invention similaire à celle des figures 1 a et 2b,  FIG. 3 is a rear side view of a seal according to an example of the invention similar to that of FIGS. 1 a and 2b,
ia figure 4 est une vue en perspective arrière de la garniture d'étanchéité de Sa figure 3,  FIG. 4 is a rear perspective view of the seal of FIG. 3,
la figure 5 est une vue partielle en demi-coupe axiale de la garniture d'étanchéité des figures 3 et 4 selon le plan V-V de la figure 3, la figure 6 est une vue en perspective arrière partiellement éclatée de cette garniture d'étanchéité telle qu'illustrée en vue assemblée à la figure 4, fa figure 7 est une vue de détail en perspective éclatée du médaillon de la figure 6 montrant des éléments assemblés, FIG. 5 is a partial axial half-sectional view of the seal of FIGS. 3 and 4 along the plane VV of FIG. 3; FIG. 6 is a partially exploded rear perspective view of this seal such as shown in the assembled view in Figure 4, FIG. 7 is an exploded perspective detail view of the medallion of FIG. 6 showing assembled elements,
la figure 8 est une vue en perspective d'un composite moulé selon l'invention à partir duquel a été obtenue la garniture des figures 3-7, la figure 9 est une vue en perspective d'un moyen de fixation selon un exemple de l'invention,  FIG. 8 is a perspective view of a molded composite according to the invention from which the packing of FIGS. 3-7 has been obtained, FIG. 9 is a perspective view of a fastening means according to an example of FIG. 'invention,
la figure 10 est une vue en perspective d'un moyen de liaison anti-rotation selon un exemple de l'invention pour verrouiller les moyens de serrage,  FIG. 10 is a perspective view of an anti-rotation connection means according to an example of the invention for locking the clamping means,
la figure 11 est une vue en perspective d'une rondelle d'appui selon un exemple de l'invention utilisable entre la bride pourvue des moyens de serrage et les moyens de rappel,  FIG. 11 is a perspective view of a bearing washer according to an example of the invention that can be used between the flange provided with the clamping means and the return means,
la figure 12 est une vue en perspective d'un élément d'accrochage élastique selon un exemple de l'invention coopérant avec le moyen de liaison de la figure 10 et avec ie moyen de serrage de la figure 13, la figure 13 est une vue en perspective d'un moyen de serrage selon un exemple de l'invention coopérant avec l'élément d'accrochage de la figure 12 via le moyen de liaison de îa figure 10,  FIG. 12 is a perspective view of an elastic fastening element according to an example of the invention cooperating with the connecting means of FIG. 10 and with the clamping means of FIG. 13, FIG. 13 is a view in perspective of a clamping means according to an example of the invention cooperating with the fastening element of FIG. 12 via the connecting means of FIG. 10,
la figure 14 est une vue en section axiale d'une rondelle élastique selon un exemple de l'invention utilisable dans les moyens de rappels,  FIG. 14 is a view in axial section of an elastic washer according to an example of the invention that can be used in the recall means,
la figure 15 est une vue schématique en section axiale d'un tronçon de canalisation selon l'invention incorporant une garniture d'étanchéité selon l'invention, montrant l'étape de serrage de cette garniture, la figure 16 est une vue latérale partielle d'une garniture d'étanchéité selon l'invention en cours de serrage, telle que celle des figures 3-6, illustrant plus clairement cette étape de serrage, et  FIG. 15 is a schematic view in axial section of a pipe section according to the invention incorporating a seal according to the invention, showing the step of clamping this packing, FIG. 16 is a partial side view of a seal according to the invention being tightened, such as that of FIGS. 3-6, more clearly illustrating this clamping step, and
les figures 17a, 17b et 17c sont des vues latérales partielles de la garniture d'étanchéité de la figure 16, montrant respectivement trois phases successives de l'étape de desserrage de cette garniture.  Figures 17a, 17b and 17c are partial side views of the seal of Figure 16, respectively showing three successive phases of the loosening step of this liner.
Dans la présente description, « axial » et « axialement » se rapportent à une direction parallèle à l'axe de symétrie longitudinal X des canalisations qui est confondu avec celui des garnitures d'étanchéité, et « radial » et « radiaiement » se rapportent à une direction ou à un plan transversai à cet axe X qui contient pour une symétrie de révolution toutes les directions perpendiculaires à cet axe. In the present description, "axial" and "axially" refer to a direction parallel to the longitudinal axis of symmetry X of the pipes which is coincident with that of the seals, and "radial" and "radiaiement" refer to a direction or a plane transverse to this axis X which contains for a symmetry of revolution all the directions perpendicular to this axis.
Comme illustré aux figures 1a et 1 b, une canalisation 1 à double paroi selon l'invention est en particulier adaptée pour transporter des fluides liquides ou gazeux dont la température de transport est très différente de celle de la paroi extérieure de la canalisation 1 se trouvant au contact du milieu ambiant par exemple en eau profonde dans lequel elle est disposée,  As illustrated in FIGS. 1a and 1b, a double-walled pipe 1 according to the invention is particularly suitable for transporting liquid or gaseous fluids whose transport temperature is very different from that of the outer wall of pipe 1 located in contact with the ambient environment, for example in deep water in which it is disposed,
La canalisation 1 comprend une succession de tronçons cylindriques 2 droits qui sont optionnellement reliés entre eux par au moins un tronçon coudé et qui présentent une section transversale par exemple circulaire. Chaque tronçon 2 comprend essentiellement :  The pipe 1 comprises a succession of straight cylindrical sections 2 which are optionally interconnected by at least one bent section and which have a cross section for example circular. Each section 2 essentially comprises:
- un tube radiaiement interne 3,  a radially internal tube 3,
- un tube externe 4 coaxiai et concentrique au tube 3, et an outer tube 4 coaxial and concentric with the tube 3, and
- un garnissage annulaire 5 entre les tubes interne 3 et externe 4, qui comprend des matelas thermiquement isolants 6 montés radiaiement au contact des tubes 3 et 4 et séparés axialement deux à deux entre eux par des garnitures d'étanchéité annulaires 7 selon l'invention. an annular packing 5 between the inner and outer tubes 4, which comprises thermally insulating mats 6 mounted radially in contact with the tubes 3 and 4 and separated axially in pairs from each other by annular seals 7 according to the invention .
Chaque garniture 7 est destinée en premier lieu à solidariser mécaniquement et de façon souple le tube 3 avec le tube 4, et à assurer en outre une fonction d'étanchéité pour permettre un bon fonctionnement en mode dégradé de la canalisation 1. Ce fonctionnement en mode dégradé est illustré à la figure 1 b, qui montre un cas de brèche ou de perforation 4a accidentelle du tube externe 4 ayant généré une entrée d'eau dans un compartiment annulaire 6a rempli de l'un des matelas 6, et requiert que chaque garniture 7 conserve précisément et durablement sa position axiale et radiale entre les tubes 3 et 4 en confinant de manière étanche l'eau ayant pénétré dans ce compartiment 6a pour ne pas inonder les compartiments annulaires contigus, en dépit de Sa différence existant entre la pression Pa des compartiments thermiquement isolants 6 non inondés se trouvant sensiblement à la pression atmosphérique et la pression Pw du compartiment thermiquement isoiant intermédiaire 6a rempli d'eau (se trouvant sensiblement à la même pression que l'eau environnante). Each lining 7 is intended in the first place to mechanically and flexibly fasten the tube 3 to the tube 4, and to further ensure a sealing function to allow proper operation in degraded mode of the pipe 1. This mode operation gradient is illustrated in Figure 1b, which shows a case of breach or accidental perforation 4a of the outer tube 4 having generated a water inlet in an annular compartment 6a filled with one of the mattresses 6, and requires that each pad 7 preserves precisely and durably its axial and radial position between the tubes 3 and 4 by sealingly confining the water having entered this compartment 6a so as not to flood the contiguous annular compartments, in spite of its difference existing between the pressure Pa of the non-flooded thermally insulating compartments 6 substantially at atmospheric pressure and compartment pressure Pw thermally insulating intermediate 6a filled with water (being substantially at the same pressure as the surrounding water).
Comme visible aux figures 2a et 2b, chaque garniture d'étanchéité 7 comprend essentiellement :  As can be seen in FIGS. 2a and 2b, each seal 7 essentially comprises:
- un joint élastomère d'étanchéité annulaire 8 massif présentant deux faces frontales circonférentielles axialement avant 8a et arrière 8b en forme de couronnes circulaires radiales,  a solid annular elastomeric sealing gasket 8 having two circumferential front faces axially front 8a and rear 8b in the form of radial circular rings,
- deux brides métalliques radiales annulaires et perforées axialement avant 9a et arrière 9b (i.e. brides intrados 9a et extrados 9b, par exemple sous forme de tôles brutes de découpe) qui, à la manière d'une armature, enserrent respectivement les faces 8a et 8b en comprimant axialement le joint 8 par serrage des brides 9a et 9b via des perforations traversantes 9c de ces dernières (par exemple au nombre de douze perforations coniques 9c dans l'exemple des figures 3, 4, 6 et 8, visibles à la figure 5), pour que le joint 8 soit expansé radialement contre les tubes 3 et 4,  two annular radial metal flanges and perforated axially before 9a and rear 9b (ie intrados flanges 9a and extrados 9b, for example in the form of blank cutting plates) which, in the manner of an armature, enclose the faces 8a and 8b respectively; by compressing the gasket 8 axially by clamping the flanges 9a and 9b via through-holes 9c of the latter (for example at the number of twelve conical perforations 9c in the example of FIGS. 3, 4, 6 and 8, visible in FIG. 5 ), so that the gasket 8 is expanded radially against the tubes 3 and 4,
- une multitude de tirants cylindriques filetés axiaux 10 (voir figures 6 et 9) espacés de manière régulière dans la direction circonférentieîle qui traversent axiaiement le joint 8 et les perforations 9c des brides 9a et 9b pour fixer le joint 8 à des dernières et en dépassant axialement de la seule bride arrière 9b (par convention, celle montée à droite du joint 8 aux figures 2a, 2b et 5 et à gauche du joint 8 aux figures 4 et 6),  a plurality of axial threaded cylindrical tie rods 10 (see FIGS. 6 and 9) regularly spaced in the circumferential direction axially crossing the gasket 8 and the perforations 9c of the flanges 9a and 9b to fix the gasket 8 to the latter and protruding axially of the only rear flange 9b (by convention, that mounted to the right of the gasket 8 in FIGS. 2a, 2b and 5 and to the left of the gasket 8 in FIGS. 4 and 6),
- des moyens de serrage et de verrouillage 11 en position serrée des brides 9a et 9b contre le joint 8 qui sont montés du seul côté arrière du joint 8 autour de chaque tirant 10, et qui comprennent pour chaque tirant 10 un écrou spécial dit « auto-verrouillant » 12 (voir figure 13) coopérant avec une rondelle à griffes 13 (voir figure 12 pour chaque rondelle 13 métallique qui dans cet exemple est pourvue de cinq griffes élastiques 13a globalement axiales) avec interposition transversale d'un secteur d'arrêt ou anti-rotation 14 métallique (voir figure 10) reliant les tirants 10 deux à deux entre eux dans une direction sensiblement orthoradiale, et  - Tightening and locking means 11 in the tight position of the flanges 9a and 9b against the gasket 8 which are mounted on the only rear side of the gasket 8 around each tie rod 10, and which comprise for each tie rod 10 a special nut said "auto -locking "12 (see Figure 13) cooperating with a washer with claws 13 (see Figure 12 for each washer 13 metal which in this example is provided with five generally axial spring claws 13a) with transverse interposition of a stop sector or anti-rotation 14 metal (see Figure 10) connecting the tie rods 10 in pairs in a substantially orthoradial direction, and
- des ressorts axiaux compensateurs de dilatation 15 qui sont respectivement montés autour des tirants 10 axialement entre la bride arrière 9b et les secteurs d'arrêt 14 (ces derniers formant ainsi des portées pour ces ressorts 15) et qui sont chacun constitués dans cet exemple de réalisation d'un empilement axial de rondelles élastiques 15a par exemple de type Believille (détaillées à la figure 14), chaque ressort 15 qui est de type à compression étant adapté pour s'opposer aux effets des contraintes axiales sur les tirants 10 générées par la dilatation thermique du joint 8 en fonctionnement, pour obtenir en permanence un serrage minimal du joint 8 via le rappel axial des écrous 12 vers la face arrière 8b du joint 8 (ia figure 5 montre le sens de cette force F de rappel). - Compensating axial expansion springs 15 which are respectively mounted around the tie rods 10 axially between the flange rear 9b and stop sectors 14 (the latter thus forming spans for these springs 15) and which are each constituted in this embodiment of an axial stack of elastic washers 15a for example Believille type (detailed in Figure 14), each spring 15 which is of compression type being adapted to oppose the effects of the axial stresses on the tie rods 10 generated by the thermal expansion of the gasket 8 in operation, to permanently obtain a minimum clamping of the gasket 8 via the axial return of the nuts 12 to the rear face 8b of the seal 8 (ia Figure 5 shows the direction of this force F return).
Le joint 8 est obtenu par surmoulage au contact des brides 9a et 9b munies de leurs perforations respectives 9c, étant précisé que ce joint 8 est moulé sans être pourvu des tirants 10 ni de son « accastillage » (comprenant les moyens de serrage 11 et les ressorts 15) pour obtenir le composite moulé 6 illustré à fa figure 8, comme expliqué ci-après.  The seal 8 is obtained by overmoulding in contact with the flanges 9a and 9b provided with their respective perforations 9c, it being specified that this seal 8 is molded without being provided with the tie rods 10 nor its "deck hardware" (including the clamping means 11 and the springs 15) to obtain the molded composite 6 shown in Fig. 8, as explained hereinafter.
Les brides avant 9a et arrière 9b sont préalablement enduites d'un revêtement adhésif (« primer » en anglais) en leurs faces radiales axialement internes 9ad et 9bd puis sont solidarisées par surmoulage aux faces avant 8a et arrière 8b respectives du joint 8 suite à la vulcanisation de ce dernier dans un moule, pour l'obtention d'une adhésion et d'une cohésion satisfaisantes entre la composition de caoutchouc vulcanisée du joint 8 moulé et le matériau métallique des brides 9a et 9b. A cet effet, on positionne de manière robuste les brides 9a et 9b ainsi adhérisées dans le moule à la manière d'inserts de surmouîage, puis l'on referme le moule de sorte à y emprisonner les brides 9a et 9b et l'on y injecte ensuite sous forte pression et à haute température la composition de caoutchouc vulcanisable destinée à former le joint 8. C'est la combinaison pression, température et temps de vulcanisation qui confère à la fois les propriétés élastiques souhaitées au joint 8 et assure la cohésion irréversible du caoutchouc vulcanisé du joint 8 sur le métal des brides 9a et 9b.  The front flanges 9a and rear 9b are previously coated with an adhesive coating ("primer" in English) at their axially internal radial faces 9ad and 9bd and are secured by overmolding to the respective front faces 8a and 8b of the gasket 8 following the vulcanization of the latter in a mold, to obtain a satisfactory adhesion and cohesion between the vulcanized rubber composition of the molded gasket 8 and the metal material of the flanges 9a and 9b. For this purpose, the flanges 9a and 9b thus adhered to the mold are firmly positioned in the manner of over-molding inserts, and then the mold is closed so as to trap the flanges 9a and 9b therein and then injecting under high pressure and at high temperature the vulcanizable rubber composition intended to form the seal 8. It is the combination of pressure, temperature and vulcanization time which confers both the desired elastic properties at the joint 8 and ensures the irreversible cohesion vulcanized rubber of the gasket 8 on the metal of the flanges 9a and 9b.
En référence à la figure 5, une garniture d'étanchéité 7 selon l'invention comprend en outre : - une multitude de bouchons métalliques 17 qui sont appliqués par exemple par sertissage contre la face axialement externe 9ac de la bride avant 9a (i.e. la bride d'où ne débouchent pas les tirants 10) de façon à boucher les perforations respectives 9c de cette bride 9a, With reference to FIG. 5, a seal 7 according to the invention furthermore comprises: a multitude of metal plugs 17 which are applied for example by crimping against the axially outer face 9ac of the front flange 9a (ie the flange from which the tie rods 10 do not open) so as to plug the respective perforations 9c of this flange 9a,
- une multitude de rondelles d'appui 18 (voir figure 11 ) métalliques qui sont appliquées chacune contre la face radiale axialement externe 9bc de la bride arrière 9b de sorte à recevoir les tirants 10 et contre chacune desquelles est monté axialement en appui l'un des ressorts compensateurs 15 également monté contre un secteur d'arrêt 14 correspondant, et  a multitude of metal bearing washers 18 (see FIG. 11) which are each applied against the axially outer radial face 9bc of the rear flange 9b so as to receive the tie rods 10 and against each of which is mounted axially in abutment with one compensating springs 15 also mounted against a corresponding stop sector 14, and
- une couche d'enrobage externe élastomère 19 qui recouvre intégralement le joint 8 et les faces externes des brides 9a et 9b en étant appliquée, d'une part, sur leurs faces axiales circonférentielles radiaiement interne 9aa, 9ba et externe 9ab, 9bb de sorte à se trouver montée au contact des tubes 3 et 4 (la couche 19 formant une barrière anti-corrosion pour chaque garniture 7 et protégeant les tubes 3 et 4 d'une usure ou d'une fissuration prématurées par contact) et, d'autre part, sur les face radiales axialement externes 9ac et 9bc des brides 9a et 9b.  an elastomeric outer coating layer 19 which completely covers the gasket 8 and the external faces of the flanges 9a and 9b by being applied, on the one hand, to their radially inner circumferential axial faces 9aa, 9ba and external 9ab, 9bb so that to be mounted in contact with the tubes 3 and 4 (the layer 19 forming an anti-corrosion barrier for each lining 7 and protecting the tubes 3 and 4 from premature wear or cracking by contact) and, on the other hand, on the axially external radial faces 9ac and 9bc of the flanges 9a and 9b.
Comme illustré aux figures 3, 4, 6 et 7, les ressorts compensateurs 15 sont montés sur les secteurs d'arrêt 14 par patres, et chaque paire de ressorts 15 forme un bloc compensateur de dilatation avec :  As illustrated in FIGS. 3, 4, 6 and 7, the compensating springs 15 are mounted on the stop sectors 14 in each case, and each pair of springs 15 forms a compensating expansion block with:
- un secteur d'arrêt 14 formant portée sur lequel chaque paire de ressorts 15 appuient et qui présente deux orifices 14' recevant respectivement deux tirants 10, et  a bearing sector 14 forming a surface on which each pair of springs 15 support and which has two orifices 14 'respectively receiving two tie rods 10, and
- une paire de rondelles 13 à griffes 13a, qui sont positionnées sur le secteur 14 via autant d'orifices de calage 14a que de griffes 13a (au nombre de cinq dans cet exemple de réalisation) formés sur ce secteur 14 pour chaque rondelle 13, et qui viennent respectivement verrouiller en position serrée deux écrous 12 auto-verrou Niants,  - a pair of washers 13 with claws 13a, which are positioned on the sector 14 via as many locking holes 14a as claws 13a (five in this embodiment) formed on this sector 14 for each washer 13, and which respectively lock in the tightened position two nuts 12 self-locking Niants,
Comme expliqué ci-dessus, le gonflement ou expansion radiale du joint élastomère 8, qui est généré par l'effort de serrage des tirants 10 via les écrous 12 à une température ambiante de l'ordre de 20° C, varie considérablement en fonction des effets de la dilatation thermique du joint 8. Or, un serrage minimum du joint 8 doit être assuré à basse température par exemple autour de 0° C, notamment dans !e cas d'une canalisation immergée en eau profonde. Comme en fonctionnement le joint 8 est presque entièrement confiné et l'élastomère ie constituant peut être considéré comme étant sensiblement incompressible, les effets de dilatation thermique positive en particulier à haute température de transport du fluide (par exemple autour de 95° C) génèrent des pressions très élevées sur les parois des tubes 3 et 4 qui induisent au final des efforts de traction additionnels sur les tirants 10 de mise en contrainte. As explained above, the radial swelling or expansion of the elastomer seal 8, which is generated by the tightening force of the tie rods 10 via the nuts 12 at an ambient temperature of the order of 20 ° C, varies considerably depending on the effects of the thermal expansion of the gasket 8. However, a minimum tightening of the gasket 8 must be provided at low temperature, for example around 0 ° C, especially in the case of a pipe immersed in deep water. As in operation the gasket 8 is almost entirely confined and the elastomer constituting it can be considered to be substantially incompressible, the effects of positive thermal expansion, in particular at high fluid transport temperature (for example around 95.degree. very high pressures on the walls of the tubes 3 and 4 which ultimately induce additional tensile stresses on the tie rods 10.
Selon l'invention, ies blocs compensateurs de dilatation précités incorporant les ressorts 15 garantissent un serrage minimal du joint 8 à basse température et limitent les contraintes dans les tirants 10 à température élevée, étant précisé que ia raideur des ressorts 15 est définie pour atténuer les variations d'efforts dues à des variations de distance dues à cette dilatation du joint 8 entre la position initiale des écrous 12 et les portées d'appui des ressorts 15 constituées des rondelles 18 appliquées sur la bride arrière 9b.  According to the invention, the aforementioned expansion compensating blocks incorporating the springs 15 guarantee a minimum tightening of the gasket 8 at low temperature and limit the stresses in the tie rods 10 at high temperature, it being specified that the stiffness of the springs 15 is defined to attenuate the variations of forces due to variations in distance due to this expansion of the gasket 8 between the initial position of the nuts 12 and the bearing surfaces of the springs 15 constituted by the washers 18 applied to the rear flange 9b.
Comme visible aux figures 7, 12 et 13, chaque écrou 12, de par sa forme spécifique, est bloqué en rotation par la rondelle 13 dans le sens du desserrage, par un indexage en rotation tous les 72° (soit un cinquième de tour) dans cet exemple de réalisation à cinq griffes de verrouillage 13a. Ce blocage mécanique automatique présente l'avantage de ne requérir aucune activation externe ni manipulation, grâce à la forme particulière et à l'élasticité des griffes 13a qui permettent leur positionnement naturel sur un profii de verrouillage 12a de chaque écrou 12 en créant un obstacle mécanique s'opposant à son desserrage (ce qui garantit ainsi un serrage fiable et « en aveugle »). On voit en particulier à fa figure 13 que ce profil de verrouillage 12a de chaque écrou 12 (à six pans 12b dans l'exemple illustré) surmonte ces pans 12b et présente cinq surfaces identiques 12c incurvées de manière convexe et à pointe radiaiement externe 12d qui sont disposées régulièrement sur la circonférence du profil 12a et qui sont reliées deux à deux entre elles par un renfoncement 12e formé entre chaque pointe 12d et la naissance de la surface incurvée 12c adjacente. As can be seen in FIGS. 7, 12 and 13, each nut 12, by its specific form, is locked in rotation by the washer 13 in the loosening direction, by indexing in rotation every 72 ° (ie a fifth of a turn) in this embodiment with five locking claws 13a. This automatic mechanical blocking has the advantage of not requiring any external activation or manipulation, thanks to the particular shape and elasticity of the claws 13a which allow their natural positioning on a locking profii 12a of each nut 12 by creating a mechanical obstacle opposing its loosening (which guarantees a reliable and "blind" tightening). FIG. 13 shows in particular that this locking profile 12a of each nut 12 (hexagon 12b in the example illustrated) overcomes these sections 12b and has five identical convexly curved surfaces 12c with an external radiating tip 12d which are regularly arranged on the circumference of the profile 12a and which are connected two to two of them by a recess 12e formed between each point 12d and the birth of the curved surface 12c adjacent.
Les rondelles élastiques Beilevilfe 15a de chaque ressort compensateur 15 présentent une géométrie globalement radiale au sein de leur empilement une fois montées autour du tirant 10 correspondant, mais on voit à la figure 14 que chaque rondelle élastique 15a, par exemple en acier, présente en fait une paroi évasée de forme tronconique convergente avec par exemple les caractéristiques dimensionnelies suivantes (données à titre non limitatif) :  The elastic washers Beilevilfe 15a of each compensating spring 15 have a generally radial geometry within their stack once mounted around the tie rod 10 corresponding, but we see in Figure 14 that each spring washer 15a, for example steel, actually has a flared wall of convergent frustoconical shape with, for example, the following dimensional characteristics (non-limiting data):
- une base 15aa définissant son diamètre externe De (de a base 15aa defining its external diameter De (of
44 mm dans l'exemple illustré), 44 mm in the illustrated example),
- un sommet 15ab destiné à entourer le tirant 10 définissant le diamètre interne Di (de 18,4 mm dans l'exemple illustré),  a vertex 15ab intended to surround the tie rod 10 defining the internal diameter Di (of 18.4 mm in the example illustrated),
- une hauteur h entre la base 15aa et le sommet 15ab (de 1 mm dans l'exemple illustré), et  a height h between the base 15aa and the top 15ab (of 1 mm in the illustrated example), and
- une épaisseur s (de 2,6 mm dans l'exemple illustré).  a thickness s (of 2.6 mm in the example illustrated).
Les figures 2a et 2b illustrent l'expansion radiale de chaque garniture d'étanchéité 7 insérée entre les deux tubes 3 et 4 d'un tronçon 2 de canalisation 1.  FIGS. 2a and 2b illustrate the radial expansion of each gasket 7 inserted between the two tubes 3 and 4 of a section 2 of pipe 1.
Pour pouvoir être introduit dans ce tronçon 2, le joint annulaire 8 doit bien entendu présenter au repos des dimensions inférieures à la dimension radiale minimale entre les tubes 3 et 4, en tenant compte des tolérances de fabrication de ces derniers. Une fois inséré, le joint 8 est comprimé axiaiement par îe rapprochement des brides 9a et 9b que l'on obtient par le serrage des écrous auto-verrouiiiants 12 sur les tirants filetés 10 sur lesquels ils sont respectivement montés, ce qui provoque le gonflement radial du joint 8 qui vient progressivement se plaquer radialement contre les deux tubes 3 et 4. Après ce contact, on poursuit le serrage jusqu'à atteindre le couple cible qui garantit une pression de contact sur les deux tubes 3 et 4 prévue suffisante pour résister aux écarts de pression Pa et Pw entre les compartiments annulaires (voir à nouveau figure 1 b).  To be introduced in this section 2, the annular seal 8 must of course have at rest dimensions smaller than the minimum radial dimension between the tubes 3 and 4, taking into account the manufacturing tolerances of the latter. Once inserted, the seal 8 is axially compressed by the approximation of the flanges 9a and 9b that is obtained by tightening the self-locking nuts 12 on the threaded tie rods 10 on which they are respectively mounted, which causes the radial swelling the seal 8 which is progressively flattened radially against the two tubes 3 and 4. After this contact, the tightening is continued until reaching the target torque which ensures a contact pressure on the two tubes 3 and 4 provided sufficient to withstand the pressure differences Pa and Pw between the annular compartments (see again Figure 1 b).
Plus précisément, on a représenté : - à la figure 2a : l'épaisseur Wo du joint 8 au repos, les diamètres interne iD0 et externe OD0 du joint 8 au repos et ia distance ho au repos entre la bride arrière 9a et chaque écrou 12, et More precisely, there is shown: - in Figure 2a: the thickness Wo of the seal 8 at rest, the internal and external diameters iD 0 0 OD of the seal 8 at rest and ia ho distance at rest between the rear flange 9a and each nut 12, and
- à la figure 2b : l'épaisseur Wi du joint 8 comprimé et les diamètres interne IDi et externe ODi du joint 8 comprimé qui correspondent respectivement au diamètre externe du tube interne 3 et au diamètre interne du tube externe 4.  in FIG. 2b: the thickness W 1 of the compressed gasket 8 and the internal diameters ID 1 and external OD 1 of the compressed gasket 8 which respectively correspond to the external diameter of the inner tube 3 and to the internal diameter of the outer tube 4.
On a illustré aux figures 15 et 16 le montage et le serrage du joint 8.  FIGS. 15 and 16 illustrate the assembly and tightening of the gasket 8.
Comme visible à ia figure 15, on commence par glisser axiaîement le joint 8 sans effort notable (i.e. sans outillage lourd spécifique) entre les deux tubes 3 et 4 grâce à ses dimensions adaptées qui varient en fonction de son état de compression. Compte tenu du faible espace d'accès disponible entre les tubes 3 et 4, on utilise pour serrer chaque écrou 12 un système de serrage 20 compact de type à clef dynamométrique 21 qui se termine par une douille d'entraînement 22 standard et qui peut passer aisément entre les tubes 3 et 4.  As can be seen in FIG. 15, the seal 8 is axially slid axially without significant effort (i.e. without specific heavy tools) between the two tubes 3 and 4 thanks to its adapted dimensions which vary according to its state of compression. In view of the limited access space available between the tubes 3 and 4, each nut 12 is used to tighten a torque-type compact clamping system 21 which terminates in a standard drive bushing 22 and which can pass through. easily between the tubes 3 and 4.
Comme visible à la figure 16, après serrage de chaque écrou 12 au couple préalablement préconisé pour les conditions choisies de fonctionnement, ces écrous 12 auto-verrouillants selon l'invention permettent en relation avec les rondelles 13 à griffes 13a de maintenir le serrage initiai des brides 9a et 9b de façon fiable et pérenne. Comme expliqué précédemment, les rondelles 13 à griffes 13a n'empêchent pas la rotation des écrous 12 dans le sens horaire A du serrage et verrouillent respectivement les écrous 12 à chaque rotation de 72° dans cet exemple illustré.  As can be seen in FIG. 16, after tightening each nut 12 to the previously recommended torque for the selected operating conditions, these self-locking nuts 12 according to the invention allow, in relation to the washers 13 with claws 13a, to maintain the initial tightening of the flanges 9a and 9b reliably and perennially. As explained above, the washers 13 with claws 13a do not prevent the rotation of the nuts 12 in the clockwise direction A of the clamping and lock respectively the nuts 12 at each rotation of 72 ° in this example shown.
Dans certains cas, il peut être nécessaire de desserrer le joint 8 expansé pour l'extraire de l'espace annulaire entre les tubes 3 et 4. Comme visible aux figures 7a-17c, la présente invention a prévu à cet effet la possibilité de desserrer les écrous 12 auto-verrouillants sans les détériorer. Pour cela, on utilise une douille d'entraînement spécifique 23 pour le desserrage qui est différente de !a douille standard 22 de serrage et qui permet de déverrouiller et de desserrer les écrous 12 dans une même opération sans avoir à manœuvrer directement ces écrous 12. On insère dans un premier temps (a douiile 23 dans l'espace annulaire entre les tubes 3 et 4 dans le sens axial P (figure 17a), puis on la fait entrer en contact avec les griffes 13a de chaque rondelle 13 (figure 17b) et ensuite on écarte ces griffes 13a par un effort exercé sur la douille 23 (figure 17c) qui a pour effet de déverrouiller i'écrou 12 et de rendre possible son desserrage que l'on effectue par rotation dans le sens anti-horaire B (voir les flèches C montrant l'écartement des griffes 13a). In some cases, it may be necessary to loosen the expanded gasket 8 to extract it from the annular space between the tubes 3 and 4. As shown in FIGS. 7a-17c, the present invention has provided for this purpose the possibility of loosening the nuts 12 self-locking without damaging them. For this, a specific drive bushing 23 is used for loosening which is different from the standard clamping bush 22 and which makes it possible to unlock and loosen the nuts 12 in the same manner. without first having to maneuver directly these nuts 12. It is inserted first a douile 23 in the annular space between the tubes 3 and 4 in the axial direction P (Figure 17a), then makes it come into contact with the claws 13a of each washer 13 (FIG. 17b) and then these claws 13a are spread apart by a force exerted on the bushing 23 (FIG. 17c) which has the effect of unlocking the nut 12 and making possible its loosening which is carried out by counter-clockwise rotation B (see the arrows C showing the spacing of the claws 13a).
D'une manière générale, on notera que le système de serrage/ desserrage 20-23 selon l'invention des écrous 12 via les rondelles 13 à griffes 13a peut être avantageusement utilisé dans toute application mécanique nécessitant un serrage sécurisé, et où l'opération de serrage/ desserrage doit être effectuée avec un accès réduit au seul passage d'un outil de serrage.  In a general manner, it will be noted that the tightening / loosening system 20-23 according to the invention of the nuts 12 via the washers 13 with claws 13a can be advantageously used in any mechanical application requiring a secure clamping, and where the operation tightening / loosening must be carried out with reduced access to the only passage of a clamping tool.

Claims

REVENDICATIONS
1) Garniture d'étanchéité annulaire (7) adaptée pour relier radiaiement de manière étanche deux tubes concentriques (3 et 4) l'un à1) Annular seal (7) adapted to radially connect tightly two concentric tubes (3 and 4), one to
5 l'autre, la garniture comprenant : The other, the liner comprising:
- un joint élastomère d'étanchéité annulaire (8) présentant deux faces frontales circonférentielles (8a et 8b) axialement opposées,  an annular elastomeric sealing gasket (8) having two axially opposite circumferential front faces (8a and 8b),
- deux brides (9a et 9b) qui enserrent respectivement lesdites faces frontaies en comprimant iedit joint axialement de sorte que ledit joint0 soit expansé radiaiement en appuyant contre lesdits tubes,  two flanges (9a and 9b) respectively enclosing said front faces by compressing said joint axially so that said joint is radially expanded by pressing against said tubes,
- des moyens de fixation ( 0) qui fixent ledit joint auxdites brides en traversant axialement ledit joint, et  fastening means (0) which fix said gasket to said flanges by passing axially through said gasket, and
- des moyens de serrage (11 ) qui sont montés axialement à l'extérieur d'une dite bride (9b) et qui coopèrent avec lesdits moyens de5 fixation pour exercer un effort de serrage axial sur ledit joint par lesdites brides,  clamping means (11) which are mounted axially outside said flange (9b) and which cooperate with said fastening means to exert an axial clamping force on said seal by said flanges,
caractérisée en ce que la garniture comprend en outre des moyens de rappel (15) qui rappellent lesdits moyens de serrage axialement vers ledit joint, de sorte que ledit effort de serrage compense une dilatation o thermique dudit joint en fonctionnement en demeurant sensiblement constant.  characterized in that the liner further comprises return means (15) which recall said clamping means axially towards said seal, so that said clamping force compensates thermal expansion o said operating seal remaining substantially constant.
2) Garniture d'étanchéité (7) selon la revendication 1 , caractérisée en ce que lesdits moyens de rappel (15) sont montés axialement entre ladite une bride (9b) et lesdits moyens de serrage (11 ).2) seal (7) according to claim 1, characterized in that said biasing means (15) are mounted axially between said one flange (9b) and said clamping means (11).
5 5
3) Garniture d'étanchéité (7) selon la revendication 1 ou 2, caractérisée en ce que lesdits moyens de fixation (10) comprennent des organes axiaux filetés (10) tels que des tirants, qui traversent ledit joint (8) de manière circonférentiellement espacée et qui dépassent chacun axialement 0 de ladite une bride (9b) en une portion de dépassement (ho) recevant lesdits moyens de serrage (11 ) et lesdits moyens de rappel (15), aucun desdits organes (10) ne dépassant de l'autre dite bride (9a). 4) Garniture d'étanchéité (7) selon une des revendications précédentes, caractérisée en ce que lesdites brides (9a et 9b) présentent chacune une structure annulaire métallique continue les rendant suffisamment flexibles pour contrôler ledit effort de serrage. 3) A seal (7) according to claim 1 or 2, characterized in that said fastening means (10) comprise threaded axial members (10) such as tie rods, which traverse said seal (8) circumferentially spaced and each protruding axially 0 from said one flange (9b) into an overflow portion (ho) receiving said clamping means (11) and said biasing means (15), none of said members (10) protruding from the other said flange (9a). 4) seal (7) according to one of the preceding claims, characterized in that said flanges (9a and 9b) each have a continuous metal annular structure making them sufficiently flexible to control said clamping force.
5) Garniture d'étanchéité (7) selon une des revendications précédentes, caractérisée en ce que 2n dits moyens de fixation ( 0), 2n dits moyens de serrage (11 ) et 2n dits moyens de rappel (15) (n entier naturel égal ou supérieur à 2 et de préférence égal ou supérieur à 4) sont montés de manière circonférentiellement espacée axialement en regard desdites faces frontales (8a et 8b) dudit joint (8), de sorte que lesdits 2n moyens de rappel (15) rappellent respectivement iesdits 2n moyens de serrage en les contraignant axialement vers lesdits 2n moyens de fixation. 5) seal (7) according to one of the preceding claims, characterized in that 2n said fixing means (0), 2n said clamping means (11) and 2n said return means (15) (n natural whole equal or greater than 2 and preferably equal to or greater than 4) are mounted circumferentially spaced axially facing said end faces (8a and 8b) of said seal (8), so that said 2n return means (15) respectively recall said 2n clamping means by binding them axially to said 2n fastening means.
6) Garniture d'étanchéité (7) selon la revendication 5, caractérisée en ce que lesdits 2n moyens de rappel (15) comprennent des ressorts de type à compression (15) comportant de préférence un empilement de rondelles élastiques (15a), lesdits ressorts étant montés radialement autour desdits 2n moyens de fixation ( 0) et axialement en appui entre ladite une bride (9b) et n moyens de liaison anti-rotation (14) que comprend la garniture et qui relient deux à deux entre eux lesdits 2n moyens de fixation (10) pourvus desdits 2n moyens de serrage (11 ) en s'opposant à leur rotation. 7) Garniture d'étanchéité (7) selon la revendication 6, caractérisée en ce que lesdits n moyens de liaison (14) comprennent chacun une patte anti-rotation (14) en forme de secteur d'anneau qui est verrouillée sur une paire desdits 2n moyens de serrage (11 ), lesdits 2n moyens de serrage comprenant chacun un écrou de verrouillage (12) coopérant avec un élément d'accrochage élastique (13), ledit élément d'accrochage tel qu'une rondelle (13) à griffes (13a) étant monté sur une dite patte et verrouillant angulairement ledit écrou. 8) Garniture d'étanchéité (7) seîon une des revendications précédentes, lesdites brides (9a et 9b) présentant chacune une face axiale circonférentielle radialement externe (9ab et 9bb), une face axiale circonférentielle radialement interne (9aa et 9ba), une face radiale circonférentielle axialement externe (9ac et 9bc) et une face radiale circonférentielle axialement interne (9ad et 9bd) en contact avec ledit joint (8), caractérisée en ce que la garniture comporte une couche d'enrobage externe élastomère (19) qui recouvre lesdites brides en lesdites faces axiales radialement interne et externe et en ladite face radiale axialement externe et qui est destinée à être montée au contact desdits tubes (3 et 4). 6) A seal (7) according to claim 5, characterized in that said 2n biasing means (15) comprises compression-type springs (15) preferably comprising a stack of spring washers (15a), said springs being mounted radially around said fixing means 2n (0) and axially in abutment between said one flange (9b) and n anti-rotation connection means (14) which comprises the lining and which connect in pairs to each other said 2n means of fixation (10) provided with said 2n clamping means (11) opposing their rotation. 7) seal (7) according to claim 6, characterized in that said n connecting means (14) each comprise a ring sector anti-rotation tab (14) which is locked on a pair of said 2n clamping means (11), said 2n clamping means each comprising a locking nut (12) cooperating with an elastic hooking element (13), said hooking element such as a washer (13) with claws ( 13a) being mounted on a said tab and angularly locking said nut. 8) seal (7) according to one of the preceding claims, said flanges (9a and 9b) each having a radially outer circumferential axial face (9ab and 9bb), a radially inner circumferential axial face (9aa and 9ba), a face an axially outer circumferential radial (9ac and 9bc) and an axially inner circumferential radial face (9ad and 9bd) in contact with said gasket (8), characterized in that the gasket comprises an elastomeric outer coating layer (19) which covers said flanges in said radially inner and outer axial faces and in said axially outer radial face and which is intended to be mounted in contact with said tubes (3 and 4).
9) Garniture d'étanchéité (7) selon la revendication 8, caractérisée en ce que ia garniture est obtenue par un surmoulage desdites brides (9a et 9b), par injection dans un moule et au contact desdites brides d'une composition de caoutchouc vulcanisable destinée à constituer ledit joint (8) pour l'obtention d'un composite moulé (16) comprenant ledit joint vulcanisé enserré par lesdites brides, ladite face radiale axialement interne (9ad, 9bd) de chacune desdites brides à surmouter étant revêtue d'un agent d'adhérisation pour faire adhérer lesdites brides auxdites faces frontales (8a et 8b) dudit joint par vulcanisation de ladite composition injectée. 9) seal (7) according to claim 8, characterized in that the lining is obtained by overmoulding said flanges (9a and 9b), by injection into a mold and in contact with said flanges of a vulcanizable rubber composition intended to constitute said seal (8) for obtaining a molded composite (16) comprising said vulcanized gasket sandwiched by said flanges, said axially inner radial face (9ad, 9bd) of each of said overflow flanges being coated with a adhesive agent for adhering said flanges to said front faces (8a and 8b) of said gasket by vulcanizing said injected composition.
10) Dispositif étanche de liaison mécanique (5) entre au moins une paire de tubes concentriques radialement interne (3) et externe (4) d'une canalisation (1 ) qui définissent entre eux un espace de section transversale annulaire, le dispositif comprenant des matelas annulaires thermiquement isolants (6) remplissant ledit espace et des garnitures d'étanchéité annulaires (7) montées en appui radiai contre lesdits tubes interne et externe et séparant deux dits matelas axialement adjacents, caractérisé en ce que chacune desdites garnitures d'étanchéité est telle que définie à Tune des revendications précédentes. 11 ) Canalisation (1 ) utilisable pour transporter des hydrocarbures liquides ou gazeux et destinée à être immergée en eau profonde, ou bien pour transporter de la vapeur d'eau dans un réseau de chauffage urbain, la canaiisatton comprenant au moins une paire de tubes concentriques radia!ement interne (3) et externe (4) qui définissent entre eux un espace de section transversale annulaire, caractérisée en ce que la canalisation comprend dans ledit espace un dispositif (5) selon la revendication 10. 12) Procédé de fabrication et d'assemblage d'une garniture d'étanchéité (7) selon une des revendications 1 à 9, caractérisé en ce que le procédé comprend essentiellement les étapes suivantes : 10) Sealing device for mechanical connection (5) between at least one pair of radially inner (3) and outer (4) concentric tubes of a pipe (1) which define between them an annular cross-sectional space, the device comprising thermally insulating annular mattresses (6) filling said space and annular seals (7) mounted in radial support against said inner and outer tubes and separating two said axially adjacent mattresses, characterized in that each of said seals is such as defined in one of the preceding claims. 11) Canalisation (1) used to transport liquid or gaseous hydrocarbons and intended to be immersed in deep water, or for transporting water vapor in a district heating network, the canaiisatton comprising at least one pair of concentric tubes internal radii (3) and external (4) which define between them a space of annular cross-section, characterized in that the channel comprises in said space a device (5) according to claim 10. 12) Method of manufacture and assembly of a seal (7) according to one of claims 1 to 9, characterized in that the method essentially comprises the following steps:
a) un surmoulage desdites brides (9a et 9b), par injection dans un moule et au contact desdites brides d'une composition de caoutchouc vulcanisable destinée à constituer ledit joint (8), pour l'obtention d'un composite moulé (16) comprenant ledit joint vulcanisé enserré par lesdites brides,  a) overmoulding said flanges (9a and 9b), by injection into a mold and in contact with said flanges of a vulcanizable rubber composition intended to constitute said seal (8), for obtaining a molded composite (16) comprising said vulcanized seal sandwiched by said flanges,
b) un montage desdits moyens de fixation (10) axialement à travers ledit composite moulé, et  b) mounting said fastening means (10) axially through said molded composite, and
c) un montage desdits moyens de serrage (11 ) sur lesdits moyens de fixation par l'intermédiaire desdits moyens de rappel ( 5).  c) mounting said clamping means (11) on said fixing means via said biasing means (5).
13) Procédé selon la revendication 12, caractérisé en ce que l'on recouvre en outre au moins lesdites brides (9a et 9b) d'une couche d'enrobage externe élastomère (19). 13) The method of claim 12, characterized in that is further covered at least said flanges (9a and 9b) of an elastomeric outer coating layer (19).
14) Procédé selon la revendication 12 ou 13, caractérisé en ce que l'on revêt avant l'étape a) une face radiale circonférentielle axialement interne (9ad, 9bd) de chacune desdites brides (9a et 9b) d'un agent d'adhérisation pour faire adhérer lesdites brides auxdites faces frontales (8a et 8b) dudit joint (8) par vulcanisation de ladite composition de caoutchouc injectée. 15) Procédé selon une des revendications 12 à 14, caractérisé en ce qu'après l'étape c) : 14) Method according to claim 12 or 13, characterized in that it is coated before step a) an axially inner circumferential radial face (9ad, 9bd) of each of said flanges (9a and 9b) of an agent. adhering to adhere said flanges to said front faces (8a and 8b) of said seal (8) by vulcanizing said injected rubber composition. 15) Method according to one of claims 12 to 14, characterized in that after step c):
- on serre lesdits moyens de serrage (11 ) positionnés entre lesdits tubes concentriques (3 et 4), lesdits moyens de serrage comprenant chacun un écrou de verrouillage (12) coopérant avec un élément d'accrochage élastique (13) tel qu'une rondelle (13) à griffes (13a) verrouillant angulairement ledit écrou, en manœuvrant dans un sens de serrage (A) ledit écrou par une clef d'entraînement (21 ) par exemple dynamométrique se terminant par une douille de serrage (22) dudit écrou, et en ce qu'optionnellement  said clamping means (11) positioned between said concentric tubes (3 and 4) are tightened, said clamping means each comprising a locking nut (12) cooperating with an elastic fastening element (13) such as a washer (13) with claws (13a) angularly locking said nut, by operating in a tightening direction (A) said nut by a driving key (21), for example a torque gauge ending in a clamping sleeve (22) of said nut, and in that optionnally
- on desserre lesdits moyens de serrage positionnés entre lesdits tubes concentriques, en manœuvrant uniquement ledit élément d'accrochage élastique dans un sens inverse de desserrage (B) de manière à décrocher ledit élément d'accrochage dudit écrou.  - Loosening said clamping means positioned between said concentric tubes, by operating only said elastic hooking element in a reverse loosening direction (B) so as to disengage said hooking element of said nut.
PCT/FR2015/050363 2015-02-13 2015-02-13 Annular packing material for a pipe with two tubes, device and pipe incorporating said packings and method for producing and assembling same WO2016128626A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113431900A (en) * 2021-05-25 2021-09-24 徐扬 Rubber sealing rubber strip

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58142073A (en) * 1982-02-18 1983-08-23 Nippon Pillar Packing Co Ltd Seal device
EP0681135A2 (en) * 1994-05-07 1995-11-08 Werner Hauff Device for the passage of conduits through an opening in a wall
EP0826124B1 (en) 1995-05-16 1999-11-24 British Steel plc Annular separators for double walled pipe structures
EP0932795B1 (en) 1996-10-21 2003-08-13 Corus UK Limited Double walled pipe structures

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58142073A (en) * 1982-02-18 1983-08-23 Nippon Pillar Packing Co Ltd Seal device
EP0681135A2 (en) * 1994-05-07 1995-11-08 Werner Hauff Device for the passage of conduits through an opening in a wall
EP0826124B1 (en) 1995-05-16 1999-11-24 British Steel plc Annular separators for double walled pipe structures
EP0932795B1 (en) 1996-10-21 2003-08-13 Corus UK Limited Double walled pipe structures

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113431900A (en) * 2021-05-25 2021-09-24 徐扬 Rubber sealing rubber strip

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