WO2000008373A1

WO2000008373A1 - Device for protecting parting lines between tube sections designed to constitute a pipeline in particular

Info

Publication number: WO2000008373A1
Application number: PCT/FR1998/001720
Authority: WO
Inventors: Jean-Rémy Bost
Original assignee: S.A.R.L. Polymat
Priority date: 1998-07-31
Filing date: 1998-07-31
Publication date: 2000-02-17
Also published as: AU8986898A

Abstract

The invention concerns a device for protecting welded parting lines (3) between metal tube sections (1, 1') designed to constitute a piping system such as a pipeline, which tube sections (1, 1') are coated with a protective material layer (2), of concrete for instance, which does not extend up to their end parts. Said device is formed by sealing means (5) for protection against corrosion in particular, which are urged to cover the parting lines (3) and whereon a tubular shell (6) is urged to be positioned for protection against shocks to fill up the space between the edges (4) of the layers (4) of protective material (2), on either side of the parting line (3). Said shock absorbing tubular shell (6) consists of one or several prefabricated elements provided with arrangements incorporated in their thickness which enable them to be mechanically locked directly or via suitable assembling means positioned in their thickness, on the parting line (3) between the edges (4) of the layers of protective material (2). In a possible embodiment, the shell (6) consists of two half-shells (7) assembled by bolting (8).

Description

DEVICE FOR PROTECTING LINES BETWEEN TUBE SECTIONS FOR FORMING A PIPELINE IN PARTICULAR

The present invention relates to a device for protecting the junction lines between the sections of metal tubes which are intended to form a pipeline or the like, which sections of tubes are coated with a layer of protective material, in concrete for example, which does not 'not extend to their ends.

Conventionally, in the maritime environment or on land, pipelines intended for the transport of liquids or gases are constructed by assembling prefabricated tubular sections.

These prefabricated sections consist of a steel tube whose length can be between 10 and 15 m and whose diameter can be of the order of 0.8 to 1.2 m. A concrete coating layer, of the order of 4 to 10 cm thick, protects the steel tube against impact, during installation, or afterwards when the pipeline is in use. To allow the operation of assembling the tubular sections by welding, the protective coating layer does not extend to the ends of the steel tube; the edges of this protective layer are generally set back with respect to the two ends of this tube, by a distance which can be of the order of 20 to 40 cm. After radiography, the welded junction lines of the tubular sections are protected from corrosion by a sealed envelope which may consist of sticky strips of suitable material. Finally, the space between the edges of the protective layers of the two butted sections is filled with a ring of concrete or putty poured in place.

This ring of concrete or putty forms a shell which protects against shock the junction line and the ends of the steel tubes. This shell manufactured on site is formed in the continuity of the protective layers of concrete, and a tubular structure of substantially constant diameter is obtained. The pipeline is laid on the receiving soil as the junction lines are prepared and protected. In the maritime environment, it is carried out by means of trains of support rollers, starting from the floating barge on which the various sections of tubes are butted. The operation of protecting the junction lines by means of a concrete or mastic shell requires the presence, on site, of fairly significant technical and human resources; it is not very easy to implement, it is long and its cost is therefore relatively high. In the context of pipes covered by an insulating envelope, certain techniques for protecting the junction lines propose the use of prefabricated half-shells assembled by gluing (FR-A-2 710 723) or by welding (EP-A-0 029 632). At least part of the corresponding half-shells is made of suitable insulating material; bonding (or soldering) to the junction generators of the half-shells and to the circular lines of contact with the edges of the lateral protective layers is carried out in a sealed manner to protect the junction line against corrosion and, if necessary, to protect the insulating material used from humidity. The techniques described in these two documents are specially adapted for the sections of tubes associated with an insulating envelope; given the need to obtain a seal or a sealed weld, the corresponding operations are quite long and difficult to implement. The aim of the present invention is to propose a new technique for protecting the junction lines between the sections of tubes intended to form a pipeline, which is easier and quicker to implement and also less expensive.

The protection device according to the invention is of the type consisting of waterproof means of protection against corrosion, in particular which cover the junction line between the sections of tubes, on which a tubular protection shell is positioned. against shocks adapted to fill the space between the edges of the layers of protective material, on either side the junction line of the sections of tubes.

According to the invention, this tubular shell for protection against shocks consists of one or more prefabricated elements provided with arrangements integrated in their thickness which allow their direct mechanical locking or by means of suitable assembly means positioned in their thickness, on the junction line, between the edges of the layers of protective material. This technique consisting in using waterproof corrosion protection means associated with a mechanically locked impact protection shell, makes it possible to effectively protect the welded junction lines of pipelines and this by means very simple and very quick to implement. , which are immediately effective. Preferably, the thickness of this prefabricated protective shell is less than the thickness of the layer of protective material which covers the pipe sections, in particular so as not to hinder the subsequent laying operation of the pipeline.

The material of the protective shell is chosen according to the site of implantation, in order to fulfill its protective function effectively over time. It can be a metallic material, cast iron, or even concrete. Preferably, however, a molded plastic material is used, for example polyethylene or polypropylene. This material has very interesting shock absorption qualities; it is rot-proof and can be obtained from salvage products. On the other hand, the weight aspect is also very important in the envisaged application and obtaining plastic shell portions may allow the manipulation of the various elements by a single operator. The tubular impact protection shell may consist of at least two prefabricated portions provided with arrangements integrated in their thickness which allow their union. direct mechanical or by means of suitable assembly means positioned in their thickness.

According to a first embodiment, the mechanical assembly of the prefabricated portions of hulls is carried out by bolting on the joining generators of said portions. The assembly bolts extend perpendicular to said joints, in suitable orifices which are associated with positioning grooves adapted to completely integrate said bolts into the thickness of the protective shell. According to another possible embodiment, the prefabricated portions of the shell comprise at least one circular groove arranged on their external face, which allows the integration of an assembly strapping.

According to a preferred embodiment, the protective shell is made of molded plastic, such as polyethylene or polypropylene, and the assembly of the different prefabricated portions is obtained by snap-fastening of male and female monobloc parts arranged in the thickness of said portions, on their join areas. These snap-on assembly means advantageously consist of male members in the form of elongated hooks which are integrated by elasticity into female elements in the form of grooves. The prefabricated shell portions preferably comprise at least one male latching member and at least one female latching member on the same assembly edge; on the other hand, the ends of the male and female latching members are preferably bevelled to facilitate the latching operation.

In the context of these different possible embodiments, the protective shell may consist of two identical half-shells, each in the form of a half-cylinder.

This shell can also consist of four half-shells, each in the form of a half-cylinder, to form two tubular sections. juxtaposed. The half-shells then comprise partial covering means allowing a slight axial movement of said tubular sections relative to one another, with a view to adjusting their positioning as a function of the dimension between the edges of the layers of protective material. These partial recovery means advantageously consist of shoulder structures.

For this latter embodiment, the four half-shells are preferably identical and the means for partially covering the two tubular sections which are arranged on each half-shell consist of alternating inverted shoulders.

According to another possible embodiment, the tubular shell for protection against shocks is formed from a prefabricated flat plate, made of molded plastic material like polyethylene or polypropylene, deformable by bending. This flat plate is shaped into a cylinder, on site, around the welded junction line of the sections of metal tubes and its two ends are assembled with one another. Preferably, the two ends of the prefabricated plate comprise means of assembly by snap-fastening of male and female monobloc parts. The inner face of the protective tubular shell may comprise a reservation for integrating thickness related to ^the welding operation and / or anti-corrosion waterproof protection.

According to another technique for preparing the protection device, the tubular shell is positioned on the welded junction line of the sections of metal tubes and the internal seal is ensured by injection of a suitable material such as a putty, through orifices. fitted in said hull.

Other characteristics and advantages will appear in the light of the following description of several particular embodiments, given solely by way of examples and represented in the appended drawings in which: - Figure 1a is a perspective view which shows a first embodiment of the device for protecting the joining lines of butted tubular portions, consisting of two half-shells intended to be assembled by bolting; - Figure 1b shows the two half-shells assembled on the ends of the tubular portions;

- Figure 2 is an enlarged perspective view which shows one of the half-shells intended to form the protective shell according to the embodiment of Figures 1a and 1b; - Figure 3a shows another possible embodiment of the protective shell formed of two half-shells intended to be assembled by straps;

- Figure 3b shows the two half-shells assembled by straps on the ends of the tubular portions; - Figure 4 is a perspective view of another type of protective shell, consisting of four half-shells assembled two by two by strapping;

- Figure 5 is a perspective view of a half-shell provided with male / female assembly members, which is intended to associate by snap-fastening with an identical half-shell to form yet another type of shell protection;

- Figure 6 is a perspective view of a plastic plate provided with assembly means at its ends, intended to be shaped cylinder to form the protective shell; - Figure 7 shows the plate of Figure 6 shaped into a cylinder before assembly of its ends;

- Figure 8 shows the cylindrical protective shell of Figure 7, after assembly of its ends.

FIGS. 1a and 1b show two sections of tubes 1, 1 ′, made of steel for example, which are intended, after assembly, to produce a pipeline of the pipeline type. The tube sections 1 and 1 'are covered over practically their entire length with a layer of protective material 2, for example concrete.

In FIG. 1a, it can be seen that this layer of protective material 2 does not extend to the ends of the sections of tubes. This feature makes it possible to preserve sufficient space to assemble the ends of the sections 1 and 1 ′ by a welding operation.

The welded junction line of the two sections of tubes is marked at 3 in FIG. 1a. At this level, we note the edges or edges of the ends 4 of the layers of protective material 2 arranged on either side of the junction line 3, generally a few tens of centimeters from the latter. These banks 4 are substantially perpendicular to the axis of the sections of tubes 1 and 1 '.

Once the welding operation has been carried out, the weld is checked by radiography and it is protected, in particular against corrosion, by strips glued in suitable material to ensure sealing. this anti-corrosion protection 5 is illustrated in dotted lines in FIG.

The space x between the two edges 4 of the layers of protective material 2 which are arranged on either side of the junction line 3 is then filled by a protective shell 6 consisting of two half-shells 7 assembled by bolts 8.

In FIG. 1a, the two half-shells 7 are shown before assembly, on either side of the space to be filled. The protective shell 6 positioned on the junction line 3 appears in FIG. 1 b. One of the half-shells 7 of the protective shell 6 has been shown in isolation in FIG. 2.

The two half-shells 7 which form the protective shell 6 are identical; they consist of a half-cylinder of molded plastic, for example polyethylene or polypropylene. Preferably, their thickness is less than the thickness of the layer of protective material 2, so that the shell 6 once laid defines a protective cylinder whose diameter is slightly lower than that of the sections of tubes 1 and 1 ′ coated with the protective layer 2. The difference in diameter may be of the order of a few centimeters. This feature is clearly visible in Figure 1b; it allows in particular not to interfere with the laying operation of the pipeline in the open sea which is carried out by means of trains of support rollers arranged on the floating manufacturing barges.

The length I of the half-shells 7 is a function of the dimension x between the edges 4, on either side of the junction line 3. If this dimension x is not constant on the different sections of butted tubes, we may plan to adjust length | half-shells, on the same installation site, by cutting off the ends. In this case, the length of the prefabricated and delivered half-shells will be greater than or equal to the maximum dimension x. The internal diameter of the half-shells 7 can be provided slightly greater than the external diameter of the sections of tubes 1 and 1 ′ to take account of the additional thickness linked to the welding operation of the junction line 3 and to the presence of the protection anti-corrosion 5; the internal face of the half-shells 7 may also include a reservation adapted to integrate this additional thickness. The two half-shells 7 are assembled by buttoning on the two diametrically opposite joining generators.

In the illustrated embodiment, four assembly bolts 8 are provided on each joint generator. These bolts 8 extend perpendicularly to said joining lines and assembly orifices 10 are arranged accordingly on each edge 11 of the half-shells 7. To avoid the presence of projecting members or elements, the bolts assembly 8 are completely integrated into the thickness of the half-shells 7. Positioning grooves 12 extend the orifices 10 to ensure this complete integration. FIGS. 3a and 3b show another possibility of assembling the two half-shells forming the protective shell 6.

The two corresponding half-shells 14 are identical and each in the form of a half-cylinder. Their external face comprises two semicircular grooves 15 adapted for the positioning of an assembly strapping 16, for example a stainless steel strip. Figure 3a shows the two half-shells 14 before assembly and Figure 3b shows these two half-shells 14 after joining by means of the straps 16. When the two half-shells 14 are positioned on the junction line 3, between the banks 4, the pairs of half-grooves 15 come into correspondence and the straps 16 can be positioned. These straps 16 are completely integrated in their respective grooves 15.

FIG. 4 shows another embodiment in which the protective shell 6 consists of four identical half-shells

18 made of molded plastic.

The coupled half-shells 18 form two tubular sections

19 and the protective shell 6 is formed by the juxtaposition of these two tubular sections 19. The half-shells 18 are arranged so that the two tubular sections 19 come to partially overlap at their junction line and so that this partial overlap allows a slight axial movement of said sections 19 relative to each other. This feature makes it possible to adjust the positioning of the protective shell 6 between the edges 4 of the layers of protective material, to absorb any variations in dimensions from one junction line to the other.

To this end, one of the end faces 20 of the half-shells 18 comprises partial covering means consisting of shoulders 21 and in particular of alternating inverted shoulders 21 'and 21 ". In this case , as shown in FIG. 4, each half-shell 18 has two inverted shoulder structures 21 'and 21 " each occupying substantially half the thickness of said half-shells 18. These shoulders are both in the form of a quarter cylinder and the internal diameter of the shoulder 21 'is slightly greater than the external diameter of the shoulder 21 ". The opposite face 22 of the half-shells 18 is planar and it extends perpendicular to the axis of the sections 19 to come into abutment against the edges 4 of the layers of protective material 2.

The four half-shells 18 are identical; when the means for covering the two sections 19 are arranged opposite, the shoulders 21 'and 21 "of one of the sections cooperate, respectively, with the shoulders 21" and 21' of the other section.

Each tubular section 19 is formed by the association of two half-shells 18. As shown in FIG. 4, the joining edges of the half-shells can also include partial covering means which allow, if necessary , absorb the slight variations in diameter of the tube sections 1 and 1 ′, as well as any excess thickness on the junction line 3 which is linked to the welding operation and to the presence of the anti-corrosion protection. These covering means consist of complementary shoulders 23, 24 on the joining edges.

Note that this last feature can also be provided on the half-shells of the embodiment illustrated in Figures 3a and 3b.

In FIG. 4, we also note the presence of circular grooves 25 arranged on the external face of the half-shells 18 and which each allow the integration of a strip 26 ensuring the assembly of each tubular section 19.

In the embodiment shown, two lateral grooves and a central groove ensure the integration of three assembly strips 26, only one of which is illustrated, isolated, in the figure. This assembly by strapping is carried out after positioning the four half-shells on the junction line of the butted tubes 1 and the and after having adjusted this positioning between the two edges 4 of the layers of protective material 2.

FIG. 5 shows a half-shell 30 made of molded plastic material, of the polyethylene or polypropylene type which, associated with an identical half-shell simply shown diagrammatically in dotted lines, makes it possible to obtain another possible embodiment of the protective shell 6 according to the invention.

This half-shell 30 is in the form of a half-cylinder and its end edges include one-piece male 31 and female 32 parts, arranged in their thickness, which allow snap-on assembly with the homologous half-shell.

The male parts 31 are in the form of an elongated hook and the female parts 32 consist of grooves of corresponding suitable shape. One of the end edges of the half-shell 30 has two male parts 31 which frame a female part 32, while the other edge has two female parts 32 which frame a male part

31.

The assembly of the two half-shells 30 on the welded junction line of the sections of pipelines 1, the is effected by snap-fastening of the male parts 31 of one of the half-shells in the female parts

32 of the other half-shell, thanks to the elasticity of said male parts 31 and / or said female parts 32. The snap-fastening is facilitated by the presence of cut sides with inverted slopes 33 and 34 arranged, respectively, at the end of male parts 31 and female parts

32.

As each end border has at least one male part 31 and one female part 32, the two half-shells 30 are correctly locked one on the other after the latching operation and there is no risk of separation, even if the internal diameter of the protective shell 6 turns out to be greater than the external diameter of the butted tubes 1, l 'of the pipeline. In FIG. 5, we also note the reservation 35 arranged in the internal face of the half-shell 30, which makes it possible to integrate the additional thickness linked to the welding of the junction line and to the presence of the anti-corrosion protection. Figures 6 to 8 show another possible embodiment of the protective shell 6 according to the invention.

This protective shell 6 is made from a flat plate

36 made of molded plastic, such as polyethylene or polypropylene, deformable by bending, and the end edges of which comprise one-piece male 37 and female 38 parts arranged in thickness.

The male parts 37 are in the form of an elongated hook and the female parts 38 consist of grooves of corresponding suitable shape. One of the end edges of the plate 36 has two male parts 37 which frame a female part 38, while the other edge has two female parts 38 which frame a male part 37.

The flat plate 36 is shaped into a cylinder (FIG. 7) around the junction line of the pipeline sections; the assembly of its two ends is carried out by snap-fastening of the male parts 37 into the female parts 38 (FIG. 8).

This embodiment is particularly advantageous in the case of pipeline sections having a large diameter. The flat plates 36 are in fact easier to transport compared to the shell sections of the other embodiments. The cylinder conformation is carried out on the installation site by suitable mechanical bending means.

According to a particular technique for installing the protection device according to the invention, the impact protection shell 6 is positioned around the welded junction line 3, then injected between said shell 6 and said junction line 3 a suitable material for sealing. This material can be a polymerizable putty, associated or not with a hardener; it is injected into suitable orifices provided in the body of the tubular shell. Such injection orifices have been identified at 40 in the embodiment of FIGS. 6 to 8.

This technique consisting in sealing the welded junction line after positioning the shell 6 for impact protection is particularly suitable for the embodiment of plastic shells positioned by snap-fastening, illustrated in FIG. 5 on the one hand , and in Figures 6 to 8 on the other hand.

Claims

- CLAIMS - 1.- Device for protecting the welded junction lines (3) between the sections of metal tubes (1, 1 ') which are intended to form a pipeline in particular, which sections of tubes (1, 1') are coated a layer of protective material (2), made of concrete for example, which does not extend to their ends, which device is made up of waterproof means (5) for protection against corrosion, in particular which cover said line of junction (3) and which are associated with a tubular shell (6) for impact protection adapted to fill the space between the edges (4) of layers of protective material (2), on either side of said line junction (3), characterized in that it comprises a tubular impact protection shell (6) consisting of one or more prefabricated elements (7, 14, 18, 30, 36) provided with arrangements (10 , 15, 25, 31-32, 37-38) integrated in their thickness which allow their glass direct mechanical tooling or by means of suitable assembly means (8, 16, 26) positioned in their thickness, on said junction line (3), between the edges (4) of said layers of protective material (2).

2.- Device according to claim 1, characterized in that it comprises a tubular shell for protection against shocks (6) consisting of at least two prefabricated portions (7, 14, 18, 30) provided with arrangements (10 , 15, 25, 31-32) integrated in their thickness which allow their direct mechanical union or by means of suitable assembly means (8, 16, 26) positioned in their thickness.

3.- Device according to claim 2, characterized in that the mechanical assembly of the prefabricated portions (7) of the protective shell (6) is achieved by bolting on the joining generators of said portions (7), said bolts assembly (8) extending perpendicular to said joints, in suitable orifices (10) which are associated with positioning grooves (12) adapted for completely integrate said bolts (8) into the thickness of said shell (6).

4.- Device according to claim 2, characterized in that the prefabricated portions (14, 18) of the shell (6) comprise at least one circular groove (15, 25) arranged on their external face, which allows the integration of 'an assembly strapping (16, 26).

5.- Device according to claim 4, characterized in that the half-shells (18) intended to form the tubular shell (6) or simply a part (19) of this shell, comprise partial covering means in the form of shoulders (23, 24).

6.- Device according to claim 2, characterized in that it comprises prefabricated shell portions (30) made of molded plastic material such as polyethylene or polypropylene, the assembly of said shell portions being obtained by snap-fastening of male monobloc parts ( 31) and females (32) arranged in their thickness, on their joining zones.

7.- Device according to claim 6, characterized in that the means for snap-fitting the prefabricated shell portions (30) consist of male members in the form of elongated hooks (31) which are integrated by elasticity in female elements in the form of grooves (32).

8.- Device according to any one of claims 6 or 7, characterized in that the prefabricated shell portions (30) comprise at least one male latching member (31) and at least one female latching member (32 ) on the same assembly border.

9.- Device according to any one of claims 6 to 8, characterized in that the ends of the male latching members (31) and female (32) have cut sides forming bevels to facilitate the latching operation .

10.- Device according to any one of claims 2 to 9, characterized in that it comprises a tubular protective shell (6) consisting of two identical half-shells (7, 14, 30), each in the form of a half-cylinder.

11.- Device according to any one of claims 2 to 10, characterized in that it comprises a tubular protective shell (6) consisting of four half-shells (18), each in the form of half-cylinder, to form two juxtaposed tubular sections (19), said half-shells (18) comprising partial covering means allowing a slight axial movement of said tubular sections (19) relative to each other, in order to adjust their positioning in function of the dimension (x) between the edges (4) of the protective material layers (2).

12.- Device according to claim 11, characterized in that the partial covering means of the two tubular sections consist of shoulder structures (21 'and 21 ").

13.- Device according to claim 12, characterized in that it consists of four identical half-shells (18), the partial connection means of the two tubular sections (19) which are arranged on each half-shell (18) being made up of alternating inverted shoulders (21 'and 21 ").

14.- Device according to claim 1, characterized in that it comprises a tubular shell for protection against shocks (6) formed from a prefabricated flat plate (36) made of molded plastic material like polyethylene or polypropylene, which plate (36) is shaped into a cylinder around the welded junction line (3), its two ends being secured to one another.

15.- Device according to claim 14, characterized in that the two ends of the prefabricated flat plate (16) comprise assembly means by snap-fastening of male (37) and female (38) monobloc parts.

16.- Device according to any one of claims 1 to 15, characterized in that it comprises a reservation (35) arranged in the internal face of the shell portions (30), to integrate the additional thickness linked to the operation of welding and waterproof corrosion protection (5).

17.- Device according to any one of claims 1 to 15, characterized in that it consists of a tubular shell for protection against shocks (6) associated with waterproof means (5) for protecting the line of junction (3) which are made of a suitable material, such as mastic for example, injected between said junction line (3) and said tubular shell (6), after positioning of the latter, which injection of material is carried out by suitable orifices (40) arranged in said shell (6).

18.- Device according to any one of claims 1 to 17, characterized in that it comprises a tubular protective shell (6) whose thickness is less than the thickness of the layer of protective material (2) which covers the tube sections (1, l ').