MXPA00006060A - Hoses or flexible pipes - Google Patents

Abstract

A hose or flexible pipe (100;200) which has an inner lining (116;216) composed of fluoropolymer. This gives the hose an improved capacity to withstand high temperatures, chemical degradation, and embrittlement along with flexibility and light weight. The hose wall structure (102) is preferably fully bonded to improve support for the fluoropolymer lining (116;216). The fluoropolymer lining (116;216) also makes practicable the use of rubbers having the ability to withstand high temperatures. There is also described an assembly of such a hose or flexible pipe (100;200) with an end fitting (300 + 400;310 + 410) incorporating a novel pressure-actuated seal (500, 502;600;800)

Description

HOSES OR FLEXIBLE PIPES This invention relates to hoses or hoses, and relates more particularly, but not exclusively, to hoses or hoses which are adapted for the transport of hydrocarbons. As used in this specification, the terms "hose" and "flexible tube" are mutually synonymous. A hose (or flexible tube) is an elongated flexible tube suitable for the transport of fluids (liquids and / or gases), and which can adapt to different paths or trajectories without permanent deformation, for example to provide a fluid path between objects. which are in relative motion, such as a floating tanker and a production platform anchored on the seabed. Hydrocarbons produced by wells on the seabed are often chemically and physically aggressive, and consequently capable of causing unacceptable damage to transport hoses. The hoses usually require attachments at the ends whereby those ends of the hoses can be mechanically anchored and also secured in a fluid-tight manner to a source or receiver of the fluid to be transported by the hose. It is required that such end fittings be reliably sealed to the hose both to resist pressure and to resist degradation by the fluid carried by the hose. According to a first aspect of the present invention, there is provided a hose or flexible tube characterized in that the hose or flexible tube is internally coated with an internal coating comprising a fluoropolymer. The hose or flexible tube is preferably formed so that the wall of the hose or flexible tube is a structure joined at least in the part of the wall in contact with the inner lining. The wall of the hose or flexible tube is preferably a completely bonded structure. The fluoropolymer of the internal coating is preferably at least one fluoropolymer selected from the group of fluoropolymers comprising ETFE (ethyl-tetra-fluoroethylene), FEP (fluorinated ethylene propylene), HFP (hexa-fluoro-propylene), and PFA (per-fluoro). -alcozil). The hose or flexible tube may comprise reinforcing means which are preferably included in the wall of the hose or hose. The reinforcing means preferably comprises at least one reinforcement selected from the group of reinforcements comprising at least two layers of steel wire wound helically around and along the hose or flexible tube, or at least one layer of synthetic polymeric textile material, the which may comprise aramid fibers. The reinforcing means may be included in an elastomer which may comprise silicone rubber, the elastomer preferably being reinforced by an included wire. The inner lining of the hose or hose may itself be internally coated with a collapsible-resistant coating which may be in the form of a self-laced steel sheet spiral. According to a second aspect of the invention there is provided a pressure operated seal for sealing the interface between the attachment of an end mounted on and secured to an end of a hose or flexible tube and the inner lining of the hose or flexible tube, characterized in that the seal comprises at least one cavity in the end fitting, the or each cavity is contiguous with the interface and in it a respective mass of polymeric material is located in the or each cavity to be adjacent to the interface, where the or each cavity communicates with the orifice of the hose or flexible tube to transfer the pressure of the fluid in the hole of the hose or flexible tube to the respective mass of polymeric material to push the respective mass of the polymeric material against the portion of the inner lining that defines that part of the interface with which the respective cavity is contiguous. The seal may comprise discrete communication means for communicating the or each cavity with the orifice of the hose or flexible tube. The discrete communication means may comprise fluid passage means, and where there is a plurality of cavities in the end abutment, the fluid passage means can lead from a given cavity either directly to the orifice of the hose or flexible tube, or indirectly by means of another cavity which itself is communicated Directly or indirectly with the hole in the hose or flexible tube by means of additional fluid passage means. At least one cavity in the end abutment may extend circumferentially around the abutment, and the respective mass of polymeric material located in the circumferentially extended cavity may be generally toroidal. The or each generally toroidal mass of polymeric material can incorporate a respective reinforcing means which is itself generally toroidal and is preferably included in the respective mass of the polymeric material. The polymeric material of the sealing means is preferably a fluoropolymer which may be a fluoropolymer selected from the group of polymers comprising ETFE (ethyl-tetra-fluoroethylene), PTFE (poly-tetra-fluoroethylene), FEP (fluorinated ethylene propylene), HFP (hexa-fluoro-propylene), and PFA (per-fluoro-alkoxy), or a mixture of two or more fluoropolymers selected from such a group of fluoropolymers. In the sealing means, the or each mass of polymeric material may be associated with a respective non-polymeric member positioned between at least the majority of the respective mass and the inlet or inlets to the respective cavity of the fluid passage means. . The or each non-polymeric member may be formed of sheet metal and is present in or on the respective mass of polymeric material at least the portion or portions thereof adjacent to the inlet or inlets. The embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diametrical, longitudinal section of a first hose mode; Figure 2 is a diametral, longitudinal cut of a second hose mode; Figure 3 is a diametral, longitudinal, fragmented cut, on a very amplified scale, of part of the end of the first hose mode that is in the process of having an attachment secured at the end and sealed thereto; Figure 4 is a perspective view of a part forming the seal of the arrangement illustrated in Figure 3; Figure 5 is a cross section of the seal illustrated in Figure 4; Figure 6 is a diametrical, longitudinal cut of a second arrangement of the end of the hose, and the attachment, and the seal; Figure 7 is a diametrical, longitudinal section of an internal part of the attachment of the end of Figure 6 that is ready to receive a seal; Figure 8 is a view corresponding to Figure 7 and illustrating transfer molding of the seal on the inner part of the end fitting; Figure 9 is a diametrical, longitudinal cut of a third arrangement of the end of the hose, the end fitting, and the seal; Figure 10 is a diametrical longitudinal section of an internal part of the attachment of the end of Figure 9 that is ready to receive a seal; and Figure 11 is a view corresponding to the Figure 10 and showing the transfer molding of the seal on the inner part of the end fitting. Referring first to Figure 1, a first hose embodiment according to the invention is represented by a hose 100 having a tubular wall 1Q2 surrounding an orifice 104. The structure of the wall of the hose 102 is completely unitized and comprises a layer 106 of silicone rubber that incorporates yarn as a reinforcement. Included in the rubber layer 106 are two reinforcing layers 108 and 110, each reinforcing layer, 108, 110 comprising a respective steel wire spirally wound around and along the hose 100. The hose 100 is lined in one layer external 112 of rubber, such as chloroprene or Hypalon. The hose 100 optionally has an outer cover 114 of shrinking plastics which are perforated to release the gases which are filtered through the wall of the hose 102 from the orifice 104. The hose 100 is internally coated with an inner liner 116. composed of a suitable fluoropolymer, such as ETFE (ethyl-tetra-fluoroethylene), FEP (fluorinated ethylene propylene), HFP (hexa-fluoro-propylene), or PFA (per-fluoro-alkoxy). The coating 116 may be composed of other suitable fluoropolymers, or a mixture of two or more fluoropolymers. The inner liner 116 is optionally coated with an abrasion resistant layer or barrier 118 of any suitable material, for example the self-interlacing steel sheet spiral.

Several advantages arise from the use of a fluoropolymer as an internal lining material for a hose to transport hydrocarbons: (a) unlike other plastics, fluoropolymers are not ampouled due to explosive gas-induced decomposition; (b) Unlike other plastics, fluoropolymers do not require plasticizers which can be filtered out by hot dry gases transported through the hose to leave the coating brittle. As a hose lining material, fluoropolymers are typically ten times more flexible than rubbers previously used as hose liners; (c) the fluoropolymers are highly impermeable to gases, typically having a tenth of the gas permeability of the rubbers previously used as lining materials for hoses; (d) as hose lining materials, fluoropolymers can be used at much higher temperatures than other plastics; (e) fluoropolymers are flexible materials chemically more resistant to crude oil and associated gases while being practicable for large-scale use.

Referring now to Figure 2, this illustrates a second hose embodiment 200 according to the invention comprising a tubular hose 202 surrounding an orifice 204. The structure of the wall of the structure 202 is, generally, similar to the structure of the wall of the hose 102 described above with respect to the first hose embodiment 100, namely rubber reinforced with yarn 206 externally wrapped in a rubber layer 112 with an optional external layer 214 of perforated plastics, an outer coating 216 of fluoropolymer which may be the same fluoropolymer (or a mixture of fluoropolymers) as that used for the inner liner 116 of the first embodiment 100, and a more internal, optional, abrasion-resistant coating 218 of self-interlaced spiral metal sheet. The second hose embodiment 200 differs from the first hose 100 in that the layers 108 and 110 of the spirally wound steel wire reinforcement are replaced by the respective layers of aramid fabric 208 and 210 included on the rubber 206 to serve as reinforcement two layers of the hose 200. In the second form of the hose 200, the fluoropolymer inner liner 216 serves the same function as the fluoropolymer liner 116 in the first form of the hose 100, with the same advantages.

In both of the first and second forms of hoses 100 and 200, their fully bonded wall structures have the advantage of providing continuous support to the fluoropolymer inner coating, since fluoropolymers tend to flow cold under pressure and therefore Unattached hose wall structures have difficulty in providing adequate support for fluoropolymer coatings. If it is necessary or desirable that at least one wall structure of a hose according to the invention is not joined, then at least those parts of the wall structure adjacent to the inner lining should, however, be joined or formed from one another. another way to provide a substantially continuous support for the fluoropolymer coating. Fully bonded hoses and hoses are preferred since the hoses and hoses attached are generally cheaper to manufacture, lighter in weight per unit length and more flexible than hoses and hoses not attached. The use of heat-resistant fluoropolymers as internal linings in hoses and flexible hoses allows use in the walls of the hose joined by rubbers which are resistant to high temperatures to equal the greater resistance to temperature of fluoropolymers, specifically rubbers. which are more heat resistant than materials previously used in hoses (where the use of rubber was resistant to high temperature, was relevant and unnecessarily expensive in the absence of similar heat resistance for any coating material that was employed). In this way the hoses attached with fluoropolymer coatings according to the invention can transport fluids containing gases at high temperature and high pressure but without the risk of delamination or inherent degradation of the hoses of the prior art. In particular, a hose bonded with fluoropolymer coating can withstand up to 200 ° C (which is a temperature 70 ° C warmer than any hose of the prior art that can withstand indefinitely), and is at the same time considerably more light and more flexible than the hoses of the prior art. Referring now to Figure 3, it illustrates in longitudinal, diametrical, and on a much more amplified scale, part of the end of hose 100 (equivalent to the upper left corner of Figure 1) and parts 300 and 400 of an attachment of the end to be secured to the end of the hose 100. The end fitting is initially in two parts, namely an inner sleeve of suitable profile 300 and an outer sleeve of suitable profile 400, which are respectively placed inside and outside the end of the hose. the hose (as described in Figure 3 to partially penetrate / overlap the end of the hose, with portions of each part of the attachment (to the left of the portions shown in Figure 3) and no longer shown in the Figure 3) remaining beyond the end of hose 100. (End fittings that are similar but not identical are shown more fully in Figures 6 and 9 to which and refer to complete the context of Figure 3). To assist in the proper connection of the end fitting, certain layers of the wall of the hose 102 are cut back as shown in Figure 3. The outer plastic cover 114 is substantially completely removed from the end portion of the hose. the hose that is to be inside the end fitting, and the self-interlacing abrasion-resistant spiral 118 is cut back to about half the distance that the end of the hose will penetrate the end fitting. From the essential bonded structure of the wall of the hose 102, the rubber lining 112, the fluoropolymer coating 116 and the portions of the rubber layer 106 radially inward from the reinforcing layer 108 and radially outward from the reinforcing layer 110 are separated approximately one quarter of the depth of penetration of the hose into the reinforcing layer 110. end attachment. This leaves the reinforcement layers 108 and 110, along with most of the rubber 106 as if sandwiched between layers 108 and 110, uncut (saving the possible preliminary ordering of each end of the hose to remove any excessive unevenness). When the sleeves 300 and 400 are suitably located on the pre-cut end of the hose 100 as shown in Figure 3, the sleeve portions that line the end of the hose are stamped on the end of the hose to compress and trap permanently the hose, the straight end of the internal part of the abutment 300 expands radially and the straight end of the external part of the abutment 400 is compressed radially. When the stamping is complete, the sleeves 300 and 400 are welded together at remote points of the hose 100, or otherwise mutually secured in a suitable manner, and thus formed (together with any other necessary parts of the attachment) in an attachment Unitary end by which the hose 100 can be anchored and mechanically coupled in a fluid-tight manner to a source or receiver of fluids to be conveyor through the hose.

Although end fittings that are stamped onto conventional hoses are usually suitably leak-tight, the most extreme conditions under which the hoses of the present invention are used present additional sealing problems, aggravated by the tendency of the coating internal fluoropolymer to flow cold. To counteract such problems, and to ensure reliable sealing between the hose and its end fitting, the arrangement shown in Figure 3 incorporates a pair of active seals which will now be described in detail. Referring again to Figure 3, the sealing of the end fitting 300 and 400 to the hose 100 is based on a primary active seal 500 and a secondary active seal 502. The primary and secondary seals 500 and 502 have mutually identical structures of a single shape. generally toroidal, but operate under different conditions (as will be detailed later). The details of one of the individual seals 500 and 502 will be given below with reference to Figures 4 and 5. The primary active seal 500 is housed in a cavity 504 that has the shape of a circumferential groove machined at the periphery of the part. internal of the end fitting 300, where that part will form an interface with the hose in the fully mounted end fitting.

The cavity or slot 504 has a width in the longitudinal direction of the part of the attachment 300 (horizontally in Figure 3) which is slightly larger than the length of the total axis of the seal 500. The slot 504 has a depth in the radial direction of the part of the attachment 300 (vertically in Figure 3) which is somewhat smaller than the radial dimension of the seal 500 in its relaxed condition (i.e. the radial extension from the internal to external faces in the absence of external forces), but marginally greater than the radial dimension of the seal 500 in its attached condition (i.e. the radial extension from the inner to outer faces when compressed just enough to collapse an internal space, which will be fur detailed with reference to Figures 4 and 5) . In this way the cavity 504, when joined by the adjacent portion of the cladding 116 with which the attachment part 300 and the cavity 504 form an interface, holds the seal 500 in a condition in which it is not radically relaxed or radially closed . The cavity 504 is joined by three separate perforations 506 (only one of which is visible in Figure 3) to the vicinity of the abrasion-resistant coating 118 and consequently to the fluid in the hole of the hose 104 by means of spaces between the turns in the spiral sheet layer 118. In this way the cavity 504 and on one side of the seal 500 (the right side of the cavity 504 as seen in Figure 3) are exposed to any pressure prevailing in the hole of the hose 104. The secondary active seal 502 (which is structurally and dimensionally identical to the seal 500) is housed in a cavity 508 in the form of a circumferential groove which is dimensionally identical to the cavity or groove 508, the cavity 508 is also formed in the periphery of the inner part 300 of the end fitting but axially beyond the end of the fitting leading to the hole of the hose 104. The cavity 508 is bound on one side (the right side). echo as seen in Figure 3) by three separate perforations 510 (only one of which is visible in Figure 3) beside the cavity 504 (the left side as seen in Figure 3) in places which are each separated by the seal 500 of the inlets towards the cavity 504 from the perforations 506 (those entries are on the right side of the cavity 504 as seen in Figure 3). In this way, while one side of the primary active seal 500 (the right side as seen in Figure 3) is exposed to all the pressure in the hole of the hose 104, the corresponding side of the secondary active seal 502 (also the right side as seen in Figure 3) is exposed only to the pressure of any leaks along the seal 500. This difference in the types of pressure to which the seals 500 and 502 are respectively exposed gives rise to their functional differences, as denoted by the terms "primary" and "secondary", respectively. The term "active" also applied to both seals 500 and 502 arises from the structure of these seals which causes the outer half of each seal to tend to expand radially outward when exposed to a pressure differential axially through the seal, as will now be described in detail with reference to Figures 4 and 5. Figure 4 is a perspective view of one of the seals 504 or 502 complete, while Figure 5 is a cross section of the seal 500 (or 502) taken on the line VV in Figure 4 and presented on an amplified scale with respect to the scale of Figure 4. The seal 500 is generally toroidal (Figure 4) with a cross section which is externally an almost rectangular trapezoid (Figure 5) when it relaxes (ie free of external forces). More significantly, the seal 500 has a cross section which is approximately U-shaped, having a longitudinally extending internal part 520, and a longitudinally extending outer part 522, those portions 520 and 522 are mutually coupled at an axial end of the seal on a radially extending part 524. The parts 520, 522 and 524 are not mutually distinct since the seal 500 is integrally formed, and reference is made to the different parts of the seal only to facilitate the following Functional description. The seal 500 contains a U-shaped titanium strip 526 (Figure 5) around which the fluoropolymer is molded, except for a slot 528 extending along the center of the U-shaped strip 526. The groove 528 is open towards an end face of the seal 500 (the left end as shown in Figure 5 and the right end as shown in Figure 3), and therefore defines the three parts of seal 520, 522 and 524. Returning to Figure 3, the seals 500 and 502 are placed in their respective cavities or grooves 504 and 508 before the inner sleeve 300 of the end fitting is offered to the end of the hose 100. When the end fitting is assembled and stamping on the end of the hose, with the seals 500 and 502 in place as indicated in Figure 3, and the hole in the hose 104 is pressurized with a fluid to be transported through the hose 100, the fluid passes through the interstices of the spiral sheet coil constituting the layer 118 and through the perforations 506 to pressurize the right side (as seen in Figure 3) of the cavity 504. Because the seal 500 is located in the cavity 504 with a open end of its slit 528 on the right side of the cavity 504, the pressurization of the right side of the cavity 504 and the consequent pressurization of the slot or slit 528 tends to open towards the seal 500, that is to say to make the external part of seal 524 tends to expand radially outward and into firm contact with inner liner 116 of hose 100. (Internal portion 520 of seal 500 is restricted against movement radially inwardly by the underlying body of sleeve 300). The seal 500 is therefore pressure operated, ie its sealing effect is increased if the seal is made in the absence of pressure differences, at a somewhat higher level of sealing, which is a function of the pressure to be sealed. To the extent that imperfections in the seal allow the fluid to pass into the primary seal 500, such as leaks to the left side of the cavity 504 (as seen in Figure 3), an increase in pressurization will be transferred via the perforations 510 to the right side of the secondary seal 502, and will therefore cause the pressure actuation of the seal 502 to be carried out as a reinforcement to the primary seal 500. The structure and function of the secondary seal 502 are the same as for the primary seal 500, with the only substantive differences between those seals being in their respective locations and pressurization sources.

Figure 6 shows another arrangement of the end of the hose, the end fitting and the active seal, this other arrangement is similar to the principle of the arrangement of Figure 3, but different in detail. As with the anterior end fitting, in the arrangement of Figure 6 the end fitting is initially in two parts, namely an internal sleeve of suitable profile 310 and an outer sleeve of suitable profile 410 which are respectively placed inside and outside. from the end of the hose 100. In the arrangement of Figure 6, the inner sleeve 310 is sealed to the inner liner 116 of the hose 100 by an active seal 600 of generally toroidal shape. The seal 600 is formed of a fluoropolymer of suitable properties and can be one of the fluoropolymers of which the internal coating 116 is selected, or a mixture of such fluoropolymers. The seal 600 is located in a cavity that has the shape of a circumferential groove 602 on the peripheral face of the inner sleeve 310. Because the cavity or groove 602 is cut inwardly from the periphery of the sleeve 310 in a portion of the sleeve 310 , which is inside the hole of the hose 104 and in contact with the inner liner 116, the cavity 602 is contiguous with the interface between the inner liner 116 and the inner sleeve 310 of the end fitting. The cross section of the cavity 602 is used towards the mouth of the cavity of a radially convex biangular internal surface, which somewhat resembles a truncated tip arrow head. Several separate passages 604 extend from the radial surface of the cavity 602 radially inwardly through the body of the inner sleeve to communicate the cavity 602 radially inwardly of the seal 600 with the continuation of the hole in the hose 104 through the end fitting . The center of the biangularly convex floor is capped by a circumferentially expanded toroidal strip 606 of metal, which serves to transmit fluid pressure (which rises via the passages 604 from the hole of the hose 104) to the radially inner side of the seal 600 and therefore pressurizes the seal 600 radially outward toward the sealing contact with the inner liner 116 of the hose 100. A preferred method for forming the seal 600 will now be described with reference to Figures 7 and 8. The Figure 7 shows the first stage in the formation of the seal 600. The inner sleeve 310 of the end fitting is initially separated from the outer sleeve 410, and away from the hose 100. The periphery of the sleeve 310 is formed with the circumferential cavity or groove 602, and the radial passages 604 are perforated or otherwise formed between the radially internal surface of the cavity 602 and the hole of the sleeve 310. The strip of toroidal metal 606 is then placed on the radially inner surface of the cavity 602. The strip 606 can be formed as (for example) an elastic steel ring with a single transverse groove so that it expands circumferentially enough to be placed on it. the periphery of the sleeve 310 and sliding along the sleeve until it spring into the cavity 602. Such ability of the strip 606 to circumferentially expand is also more than adequate for the pressure-driven expansion of the seal 600 in the complete seal arrangement. Figure 7 represents the preparatory step for the second step of forming the seal 600, which will now be described with reference to Figure 8. In Figure 8, the arrangement of Figure 7 was equipped with an annular mold 700 which closes tightly around the periphery of the inner sleeve 310 in the region of the periphery of the sleeve, where the cavity or groove 602 is formed. The internal face of the mold 700 is sealed to the periphery of the sleeve on both axial sides of the cavity 602 by means of non-integrated metal rings 702. The mold 700 is radially aligned on the sleeve 310 by the closed fit of its internal and external peripheries, respectively. The mold 700 is axially aligned on the sleeve 310 by means of an outer plate 704 which comes into contact with the end of the sleeve 310 when the mold 700 is at its correct axial location on the sleeve 310. The angular alignment of the mold 700 on the sleeve 310 is not essential, since the seal 600 eventually to be produced is circumferentially uniform. The annular mold 700 incorporates an injection nozzle 706 by means of which molten fluoropolymer is injected from a separate extruder (not shown) into the cavity 602 to transfer-mold the seal 600 in situ. Since the passages 604 are blocked against the outward flow of the cavity 602 by cutting those passages with the web 606, venting of gases and excess of the cavity 602 is allowed by the provision of one or more appropriately located casting orifices 706 a through the inner face of the mold 700. ~ When the injected fluoropolymer has coagulated to a sufficient degree, the mold 700 is removed from the sleeve 310 and the unacceptable surface defects in the freshly molded seal 600 are rectified. The operation of the seal 600 under pressure actuation can be tested after curing but before the installation of the sleeve 310 as part of an end fitting. Figure 9 shows an additional arrangement of the end of the hose, the end fitting and the active seal, the additional arrangement is essentially similar to the arrangement of Figure 6, and differs mainly in the details of the active seal. Compared to the seal 600 in Figure 6, the cross section of the seal 800 in Figure 9 was turned 90 ° and the taper of the seal 600 was modified to be parallel to the seal 800. The biangularly convex lower surface of the cavity 602 is now one side (the right side as seen in Figure 9) of the corresponding cavity 802, but the correspondingly angled strip 806 remains on its convex surface. While in Figure 6 the pressure transmitting fluid passages 604 extend radially, in Figure 9 the corresponding pressure transmitting passages now extend axially further in accordance with the 90 ° transformation of the seal cross section structure 800 with respect to the structure of the cross section of the seal 600 '. Figures 10 and 11 show the stages in the transfer molding of seal 800 which correspond exactly to Figures 7 and 8. Figure 9 also shows an optimal modification in which a secondary or reinforcement seal 850 can be provided, with a passage respective pressure transfer (not shown) leading to either of the cavity 802 (so that the seal 850 is actuated by pressure against leakage along the seal 800) or directly to the hole of the sleeve 310 (so that in place if it is a reinforcement seal, seal 850 is one that is driven by pressure parallel to seal 800 but cascades). Modifications and variations of the modalities described above are possible without departing from the scope of the invention. For example, two or more stamps could be provided in the arrangement of Figure 6 instead of the only stamp shown. In any of the arrangements of Figures 3, 6 or 9, the hose 100 (as detailed in Figure 1) could be replaced by the stub 200 (as detailed in Figure 2) or by any other hose having a fluoropolymer coating according to the invention. As already mentioned, the layers of the hose 114 and 118 in the hose 100 (and the corresponding layers 214 and 218 in the hose 200) are optional, and other modifications can be adopted such as (for example) providing a number of layers of reinforcement (108, 110; 208; 210) greater or less than two or omit the discrete reinforcement layers together (and place them on the yarn reinforcements mixed with the rubber of layer 106 or 206). All of the pressure-driven seal shapes already described with reference to the drawings have been toroidal and circumferentially contiguous, but it is conceivable that additional or alternative seals may be required or desired for interface areas other than complete rings, and therefore , the pressure operated seals can be limited to discrete portions of the interface whose portions are not annular, the shape of the sealing surface of the mass of the sealing material is appropriately reformed from the annular shapes illustrated. Other modifications and variations of the exemplary embodiments described above may be adopted without departing from the scope of the invention as defined in the appended claims.

Claims (20)

CHAPTER CLAIMEDICATORÍO Having described the invention, it is considered as a novelty and, therefore, the content is claimed in the following CLAIMS:

1. A hose or flexible tube, characterized in that the hose or flexible tube is internally coated with an internal coating comprising a fluoropolymer.

The hose or hose according to claim 1, characterized in that the wall of the hose or hose is a structure connected at least to the part of the wall connected by the inner lining.

3. The hose or hose according to claim 2, characterized in that the wall of the hose or hose is a completely bonded structure.

The hose or hose according to any of the preceding claims, characterized in that the fluoropolymer of the internal coating is at least one fluoropolymer selected from the group of fluoropolymers comprising ETFE (ethyl-tetra-fluoro-ethylene), FEP (ethylene fluorinated propylene), HFP (hexa-fluoro-propylene), and PFA (per-fluoro-alcozil).

The hose or hose according to any of the preceding claims, characterized in that the hose or hose comprises reinforcement means included in the wall of the hose or hose.

The hose or hose according to claim 5, characterized in that the reinforcing means comprises at least one reinforcement selected from the group of reinforcements comprising at least two layers of steel wire wound helically around and along the hose or flexible tube, or at least one layer of polymeric or synthetic textile material.

The hose or hose according to claim 6, characterized in that the synthetic polymeric textile material comprises aramid fibers.

The hose or hose according to any of claims 5, 6 or 7, characterized in that the reinforcing means are included in an elastomer.

9. The hose or hose according to claim 8, characterized in that the elastomer is a silicone rubber.

The hose or hose according to claim 8 or claim 9, characterized in that the elastomer is reinforced by included wire.

The hose or hose according to any of the preceding claims, characterized in that the fluoropolymer inner coating is itself internally coated with a coating resistant to collapse.

The hose or hose according to claim 11, characterized in that the collapsible coating is in the form of a self-interlacing spiral of steel sheet.

13. The pressure activated seal for sealing the interface between an end fitting mounted on and secured to one end of a hose or flexible tube and an inner lining of the hose or flexible tube, characterized in that the seal comprises at least one cavity in the attachment of the end, the or each cavity are contiguous with the interface, and because respective masses of polymeric material are located in the or each cavity adjacent to the interface, where the or each cavity communicates with the orifice of the hose or flexible tube to transfer the fluid pressure from the orifice of the hose or flexible tube to the respective mass of polymeric material, to push the respective mass of polymeric material against the portion of the inner liner defining that part of the interface with which the respective cavity is located. contiguous

14. The stamp in accordance with the claim 13, characterized in that the seal comprises discrete communication means for communicating the or each cavity with the hole of the hose or flexible tube.

15. The seal in accordance with the claim 14, characterized in that the discrete communication means comprise fluid passage means.

16. The seal in accordance with the claim 15, where there is a plurality of cavities in the end fitting, characterized in that any of the fluid passage means lead from a given cavity directly to the hole of the base or flexible tube, or the fluid passage means lead from a cavity given indirectly to the orifice by means of another cavity, which itself is directly or indirectly communicated with the orifice by means of additional fluid passage means.

The seal according to any of claims 13-16, characterized in that at least one cavity in the end fitting extends circumferentially around the attachment, and because the respective mass of polymeric material located in the circumferentially extended cavity is generally toroidal. .

18. The seal according to any of claims 13-17, characterized in that the polymeric material of the seal is a fluoropolymer selected from fluoropolymer groups comprising ETFE (ethyl-tetra-fluoro-ethylene), PTFE (poly-tetra-fluoro) ethylene), FEP (fluorinated ethylene propylene), HFP (hexa-fluoro-propylene), and PFA (per-fluoro-alkoxy), or a mixture of two or more fluoropolymers selected from such a group of fluoropolymers.

19. The stamp in accordance with the claim 15 or claim 16 or any of claims 17 or 18 that directly or indirectly depend on claim 15, characterized in that the or each mass of polymeric material is associated with a respective non-polymeric member placed between at least most of the respective mass and the inlet or inlets to the respective cavity of the fluid passage means.

20. The seal according to claim 19, characterized in that the or each non-polymeric member is formed of rolled metal and is present or on the respective mass of polymeric material at least in the portion or portions thereof adjacent to the entrance or entrances. .