DE3537427A1 - METHOD FOR CONNECTING PIPE SECTIONS TO A PIPELINE AND PIPE SECTION FOR A PIPELINE - Google Patents

Description

description

Process for connecting pipe sections to a pipeline and a pipe section for a pipeline

The invention relates to the connection of pipelines or pipelines with thermal insulation and are provided with corrosion protection.

Such pipelines or pipelines comprise sections or lengths of a metal pipe an anti-corrosion coating and with an insulating layer provided outside this coating as well an outer protective cover. In many applications, an outer protective cover made of rubber is preferred. if a pipeline or pipeline is constructed, then sections of these metal pipes are welded together, and then each joint area is protected from corrosion and insulated, for example with PVC foam. In certain cases, thermal insulation can be used be unnecessary.

Pipelines of this type can have various uses; a particularly interested one Use cases in this context are, for example, underwater oil pipelines in which a thermal insulation is desired and which have strict requirements in terms of corrosion protection and the Covering the pipeline are imposed, inter alia, so that mechanical stresses during laying and is resisted during operation.

The potential weak points in such a pipeline are precisely the connection areas where In addition to the welding or welding process, precautions have been taken for insulation and corrosion protection must be, which should be at least equivalent to the protection that over the remaining length of the pipe section is obtained when it is manufactured in a manufacturing facility. If an underwater pipeline is laid from a pipe-laying vessel, then the connection is made within a very made in a short time, which includes additional stringent requirements on the connection method. Here the question arises about an available time span of a few minutes for the respective connection, after which the individual pipe sections with the connecting areas are gradually drained into the water are to be laid on the floor. Such pipelines can be used in depths of up to about 200 m Transportation of oil and / or gas on the seabed can be used. The actual laying or lowering process, as previously mentioned, it also puts quite high stresses on the finished product Pipe connections.

Examples of the construction of such isolated pipelines can be found, inter alia, in the published FR patent application No. 8 221 175 and in NO patent application No. 83 47 57. However, none of these references show any satisfactory solution to the specific connection problems discussed above.

The invention is accordingly based on the object of providing a method for connecting pipelines or Pipelines of the type indicated above with the aim of reliable protection against corrosion and others at the same time occurring stresses to create if or because the connection within a

-γ- Ι a relatively short period of time at the work site concerned, which can be either on or on a laying vessel at sea or on land if the corresponding pipelines are being built on land.

The object indicated above is achieved by the invention covered in the patent claims. at a particular embodiment according to the invention, the individual pipe sections or Metal pipes used in connection with the process according to which these pipe sections become pipelines be connected, which have a greater or lesser length, which from a few 100 meters to can extend to hundreds of kilometers.

The advantages achieved by the invention are mainly that the connection is made quickly can be and that the pipe connections have a reliable corrosion protection, a Have insulation and a mechanical protective cover that can withstand various stresses such pipelines or pipelines are exposed, both during construction or laying as well as during the life of the pipeline under various operating conditions. Furthermore are the same or equivalent materials at the connection areas or locations as over the remaining length of the pipeline area used, so that a coherent and continuous or a continuous structure is provided in which an outer rubber cover Forms solid outer protection that of the outer jacket around the main part of the respective pipe section is equivalent. This outer reinforcement or tin jacket is suitably made of polychloroprene rubber, which is similar to the rubber cover. the

-δι thickness of the jacket is preferably like that Thickness of the reinforcement, e.g. 10-15 mm for the underwater oil pipelines of interest.

The invention is explained in more detail below with reference to drawings, for example.

Fig. 1 shows an embodiment of the structure at the end of a connection according to the invention prepared pipe section.

Fig. 2 shows a partially completed pipe connection.

Fig. 3 shows a sectional view of insulation elements used in the pipe connection can be.

Fig. 4 shows in an enlarged longitudinal section further details of one according to the invention pipe connection produced.

In Fig. 1, a metal pipe is shown, which is preferably a steel pipe 1 and which of a Manufacturing plant is provided with an inner corrosion protection layer 2, for example from Polychloroprene rubber can exist. Outside this layer, the pipeline has an insulating layer 3 on, which can consist of PVC foam with closed cells in a manner known per se, such as, for example made of bowl-shaped elements. Furthermore, an outer rubber casing 4 is provided, which is the insulating layer encloses sealingly. As mentioned in the introduction to the description, there are already various pipeline constructions known of this type and there can be various types of materials and manufacturing processes can be used for corrosion protection and the insulation of the pipes. As a practical rule is including sandblasting the steel pipe and, if necessary, the application of a primer or filler to be mentioned before the application of the coating 2.

With the structure of the band region of the pipe shown in FIG. 1, this pipe is prepared for a welded connection to the end of a corresponding pipe. Accordingly, the end of the tube 1 for a wedge-shaped weld seam beveled.

1 also shows a casing 5 on the outside of the reinforcement or layer 4 next to the end area of the pipe section is applied. The sheath or sheath 5 is made of rubber, if necessary. From the same rubber material from which the Layer or the coating 4 is made; it is on the outside of the cover 4 in such a way and ¥ also applied that it is attached to the cover in question with a certain pretensioning force. The application of the sheath 5 on the outside of the cover 4 can for example by means of a suitable fork-like tool, which first expands the casing 5 and then it over the pipe end with the coating 4 thereon leads and finally the relevant coating on the position shown. It can be an advantage that this rubber coating is produced by casting or pressing is so that it has high quality properties in terms of mechanical strength, service life and the like. The amount of preload can vary depending on different dimensions, which touch the pipeline construction, including the structure of the connection itself. It should, however, be seen be that the rubber material used in the sheath 5 allows a wide range of preload dimensions, so that at this point a there is great freedom of choice in terms of design or construction. In certain cases a A preload of around 15% should be suitable.

-ΙΟΙ Fig. 2 illustrates two end parts of the pipe sections while connecting. A steel pipe 1 is connected in a conventional manner by means of a weld 10 welded to a steel pipe 1A. The steel pipe 1A has a corrosion protection and an insulation, which are applied in a corresponding manner, as with regard to this of the tube 1 has been described in connection with Fig.1. After welding and, if necessary, carried out Brushing and priming creates a corrosion protection layer 12 on the connection area shown applied, which comprises the short end portions of the tubes 1 and 1A. The layer 12 can consist of a known material exist, such as rubber, which is applied by known methods can be. A great advantage is achieved if the layer 12 consists of a material which is at hardens itself to the temperatures that exist during the construction of the pipeline, and possibly also during the subsequent operation of the relevant pipeline. For example, they are self-curing Rubber / L-compositions or mixtures for these Layer has been determined to be very suitable. The thickness of the layer can be 5-6 mm, but possibly more or less, depending on the area of application.

Outside the layer 12 are two insulation elements or shells with the one shown enlarged in FIG. 3 Cross-section applied. In practice, the outside and the inside of the insulation shells 13 with a sealant such as urethane or the like. Be provided. As Illustrated in Fig. 3, the insulation shells can have a groove and a tongue 14, 15 for easy and secure attachment. From the sectional view according to FIG. 3 it can be seen that the insulation in

Form of a PVC foam lies in two layers 13A, 13B, which is an intermediate rubber layer and also on

have rubber layers corresponding to the inside and outside. These rubber layers are in Fig. 3 labeled 13C. It is advantageous that the outer rubber layer extends slightly over the edge the PVC shell extends along one longitudinal edge and that a correspondingly uncovered edge area is present on the opposite side so that there is an external overlap in the assembled insulation with this outer rubber layer will be present.

Returning to FIG. 2 is a tool 20 in the form of a vacuum or. Vacuum head can be seen, the has a pipeline 21 connected to a vacuum source comprising a pump and a vacuum tank can be connected. As shown, the vacuum head 20 is applied around the rubber jacket 5, and the pressure head can apply suction to the exertion of a negative pressure through the hose 21 on the outer surface of the sheath 5 so that this sheath is subject to expansion will be. This detaches it from the surface of the coating 4. To the sheath 5 in this way and way to solve it, it is beneficial to reduce the negative pressure effect with an initial surge of pressure reduction.

When held in the vacuum head 20 expanded Sheath 5 this is moved in the longitudinal direction of the pipeline or pipeline to the right according to FIG. 2, so that the sheathing in question inwards over the connection area and the insulation layer 13 is moved, which has previously been applied there. The length of the sheath 5 corresponds to the mutual Distance between the cut surfaces of the rubber coating on the corresponding pipe ends. If the

Vacuum head 20 has brought the casing 5 into the correct position, the vacuum effect by means of a suitable valve or the like. Canceled, and the rubber cover 5 is as a result of it Pretension firmly to get to the insulation layer 13 to the plant or to be applied.

The type and manner of the construction or assembly described here is not the only possible type and Way, because the assembly can also be carried out without the application of negative pressure. An alternative The procedure consists in placing a lubricant between the coating by means of a suitable tool 4 and the casing 5 is introduced before the necessary displacement movement takes place. A suitable one Lubricants, for example polyurethane, lead to a noticeable reduction in friction between the cover and the jacket, so that the movement by means of a hook, a clamping device Or the like. Can be made, which acts against the relevant end of the jacket, which of the Connection area is furthest away. As another alternative to loosening the sheathing and compressed air can be placed between the cover to enable the sheathing in question to be displaced and the coating is dispensed before and during the displacement. The application of compressed air can if necessary, in combination with the use of a lubricant, as mentioned above.

Regardless of the way in which the rubber sheath 5 is brought from its initial position to its assembly position above the connection area, has the sheath in question in its mounted Put a residual bias on to cause it to get around the insulation and with as much as possible Degree of sealing against the adjacent end or the

Cut surfaces of the rubber cover 4 and 4A is clamped. Line-injected or shaped rubber casing can, for example, have a residual prestress of 3 to k% . This leads to a very strong and reliable encapsulation of the connection area. Preferably, a sealant or adhesive can be applied to the various surfaces during the creation of protection and isolation of the joint area before the wrapper 5 is applied »

Further details of the resulting connection arrangement can be seen from FIG. Here are again the steel pipes 1 and 1A with the weld 10 as well the corrosion protection layer 2, the insulation layer and the coating 4 can be seen. The layer 12 in the connection area is the corrosion layer shown overlapping overlap at adjacent pipe ends. In addition, the insulation layer 13A, 13B is constructed as the sectional view of FIG. 3 illustrates. Outside the insulating layer 13A, 13B, 13C then lies the rubber covering 5, which has the same thickness as the covering 4. At the end or A sealing agent or adhesive 7 is cut surfaces on both sides of the connection area indicated as mentioned above. This material is preferably curable, and it can, for example consist of polyurethane. The corresponding seams on the surface and around the perimeter of the The assembled pipeline can advantageously be covered with an asphalt or bitumen mixture, an adhesive tape or be covered with a rubber band, which with a certain bias according to a similar Principle is applied or is like the sheathing 5. Such a rubber band 9 consists of an endless ring which is applied in advance to the pipe ends has been applied before welding and the to a fast and secure connection procedure with

- ^: '-. ":'" ■ 3537A27

wearing.

From the above it should be evident that the pipe sections produced have corrosion protection and an insulation as well as a pre-tensioned rubber coating that has been applied beforehand has been established to ensure a comfortable and reliable connection at the manufacturing or work site, like on a ship for an underwater oil pipeline, to a large extent to enable. The pipeline sections can be used in a suitable manner are dispensed from the manufacturing facility with a rubber jacket provided at one end so that each connection area has an associated jacket. However, Ss can also be a modification can be thought of providing two jackets, i.e. one, every other pipe section Sheathing at each end while other second or each intermediate pipe section has no sheathing whatsoever. As usual, a concrete layer can be applied outside the rubber coating 4 and in addition a layer of concrete can be applied over the joint area outside of the jacket will. Finally, it should be apparent that in certain applications such pipelines do not need any thermal insulation. If the pipeline is without a layer of isolation, then it can connection methods described here may also be of considerable interest and have the same advantages as described above in connection with isolated pipelines. In both Cases it is necessary that the inner metal or steel pipe have reliable protection against Corrosion and against other stresses that the arrangement has during installation and in particular is exposed to various influences during long periods of operation.

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Claims (11)

PATENTANWÄLTE Telephone (089) 29 66 84-86 η · «ι ι« «υ iwiitcoucqi lou Telex 523155mitshd Dipl.-Ing. H. MITSCHERLICH telegrams Paterrtpaap Dipl.-Ing. K. GUNSCHMANN Telecopier (089) 29 39 Dipl.-lng.Dr.rer.nat. W. KÖRBER 5KS ^ iJSS75 "803 Dipl.-Ing. J. SCHMIDT-EVERS Dipl.-Ing. W. MELZER _..... _ ._ 1 ^ Steinsdorfstrasse 10 European patent attorneys D-8000 Munich Viking-Mj ^ ndalen A / S October 21, 1985 3o5o Mj (Z $ ndalen / Norway patent claims 1. Method of joining a corrosion-protected Pipeline containing a metal pipe (1) with an anti-corrosion layer (2) and outside this layer, if necessary, an insulating layer (3) and an outer coating (4), which preferably consists of rubber, with sections of the metal tube (1,1A) on the respective Connection area are welded together (10) and then exposed to corrosion protection and if necessary. Insulated, for example with PVC foam (13, 13A, 13B), characterized in that in addition to one end of the metal tube (1) on the outside of the outer cover (4) a rubber coating (5) is applied under radial prestress that the rubber coating in question (5) after welding the metal pipe (1) to an adjacent pipe (1A) and applying a corresponding protective layer (12) and, if necessary, an insulating layer (13, 13A, 13B) on the connecting part is shifted in the longitudinal direction over the relevant connecting part, whereby the relevant rubber sheath (5) a radial elastic contraction is enabled such that it is clamped around the connecting part with a residual bias is. 2. The method according to claim 1, characterized in that that the attachment of the rubber jacket (5) next to one end of the metal pipe (1) in connection with the application of the corrosion protection layer (2) and, if necessary, the insulating layer (3) and the outer coating (4) along the metal pipe (1) is effected in a manufacturing plant and that the displacement and the final assembly of the relevant casing (5) via the connecting part the job in question is carried out while the pipeline is being laid after welding (10), the application of the corrosion layer (12) and the optionally provided insulating layer (13, 13A, 13B) on the Connecting part. 3. The method according to claim 1 or 2, characterized in that a negative pressure effect created by means of a vacuum head (20) is, which can be attached to the rubber cover (5) in such a way that the rubber cover in question expands and is displaceable by displacing the vacuum head (20) over the connecting part, whereupon the negative pressure effect is canceled and the relevant casing (5) around the connecting part contracts. 4. The method according to claim 3, characterized in that the negative pressure effect (21) takes place with a sudden pressure reduction. 5. The method according to claim 1 or 2, characterized marked that before the shift the rubber cover (5) a lubricant such as "for example Polyurethane, is introduced between the cover (4) and the sheath (5). 6. The method according to claim 1, 2 or 5, characterized in that before and during the Shifting the rubber jacket (5) compressed air between the coating (4) and the relevant sheathing (5) is dispensed. 7. The method according to any one of claims 1 to 6 d a d urch that one Rubber sheathing (5) used with a wall thickness which is almost equal to the thickness of the outer coating (4) is, and that the rubber sheathing in question (5) preferably in their mounted position with their outside flush with the outside of the cover (4) able to run. 8. The method according to any one of claims 1 to 7, characterized in that a preferably curable sealing and adhesive (7), such as polyurethane, to the insulating layer (13A, 13B) and the cut surfaces of the pipe insulation (3) and the coating (4) are released during the connection. 9. The method according to any one of claims 1 to 8, characterized in that the Seams between the mounted rubber jacket (5) and the cover (4) with an annular rubber band (9) be covered, which is brought into position and by a radial elastic bias in analogy to said sheath is held in place. 10. The method according to any one of claims 1 to 9, characterized in that as Corrosion protection layer (12) on the connecting part a self-curing or self-vulcanizing material is released, which is relatively hardens or vulcanizes at low temperatures. 11. Pipe cut or piece of pipe for a corrosion-protected Pipeline and for use in the method according to any one of claims 1 to 10 a metal pipe (1), which has a corrosion protection layer (2) and outside this, if necessary, an insulation layer (3) and an outer coating (4), which preferably consists of rubber, the short End parts of the pipe for the purpose of connection without any corrosion protection layer (2) as well as without the If necessary, provided insulating layer (3) and the coating (4) are characterized in that, in addition to at least one end part, a rubber sheath (5) is provided which surrounds the outer coating (4) with a radial pretensioning force.