System for protecting coated pipes for on-land and subsea pipelines and the method for protecting pipes

Abstract

This invention encompasses a system and a method used in the petrochemical and mechanical engineering area, more specifically in the area of protecting pipes or similarly shaped objects against external or internal damage or wear, which comprises a protective system for the ends and the inside of coated pipes, using the coating itself and other additional devices. The system is comprised of a cup (1), spacer (2), coating (3), external ring (4), and cap (5) used in the production line of the pipe-coating process, using the external coating itself, preventing corrosion and mechanical damage at the ends/bevel, in the sandblasted area of the collar and internal surface, from storage and transport to the location where it will be used, and welding in the field or on the vessel.

Claims

1. A system for protecting pipes for on-land or subsea pipelines, the pipe comprising an internal portion and an external portion, the external portion being covered by a coating, wherein the system also comprises: a cup (1); wherein the cup (1) is mechanically connected to an end of the pipe between the external portion of the pipe (6.1) and the coating (3).

2. The system of claim 1, wherein the cup (1) comprises: an internal surface of an external tab (1.2), an internal surface of an internal tab (1.3); wherein the internal surface of the internal tab (1.3) of the cup (1) is mechanically connected to the internal portion of the pipe and the internal surface of the external tab (1.2) of the cup (1) is mechanically connected to the coating.

3. The system of claim 2, wherein the cup (1) further comprises an external tab (1.1); wherein the internal surface of the internal tab (1.3) is connected to the external tab (1.1) in a part of the connection in the shape of a U, as an adjacent space between them; and wherein the pipe is positioned between the internal surface of the external tab (1.2) and the internal surface of the internal tab (1.3).

4. The system of claim 2 further comprising: a sealing element (1.4) on one end of the internal surface of the internal tab (1.3).

5. The system of claim 3 further comprising: an external ring (4); wherein the coating covers the external tab (1.1) of the cup (1) and is partially folded over the internal surface of the internal tab (1.3); and wherein the external ring (4) is configured to affix the portion of the folded coating over the cup (1).

6. The system of claim 5 further comprising a cap (5); the cap being mechanically connected to the external ring (3) and to the cup (1); and wherein the cap (5) is configured to seal the internal portion of the pipe.

7. The system of claim 6, wherein the cup includes a pressure ring (1.5), acting as a stopper between the cap (5) and the cup (1).

8. The system of claim 6, wherein the cap (5) comprises a safety valve (5.1) to relieve pressure from inside the pipe.

9. The system of claim 1 further comprising: a spacer (2); wherein the spacer (2) connects mechanically and aligns two consecutive pipes in a production line or in storage, with adequate spacing between the pipes to allow cutting relative to folding of an envelope of the coating (3).

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The present invention will be described below referencing its typical embodiments and also referencing the attached designs.

(2) FIG. 1 is a graphic representation in exploded perspective of the mentioned pipe protection system that comprises the cup (1), spacer (2), external coating (3), external ring (4) and cap (5);

(3) FIG. 2 is a graphic representation in isometric perspective of the cup (1), in accordance with a preferential configuration of the present invention;

(4) FIG. 3 is a graphic representation in isometric perspective of the spacer (2), in accordance with a preferential configuration of the present invention;

(5) FIG. 4 is a graphic representation in isometric perspective of the external coating (3), in accordance with a preferential configuration of the present invention;

(6) FIG. 5 is a graphic representation in isometric perspective of the external ring (4), in accordance with a preferential configuration of the present invention;

(7) FIG. 6 is a graphic representation in isometric perspective of the cap (5), in accordance with a preferential configuration of the present invention;

(8) FIG. 7 is a graphic representation in isometric perspective of the pipe protection system assembled on a pipe;

(9) FIG. 8 is a graphic representation in exploded perspective of the pipe after cutting and removal from the mentioned system.

DETAILED DESCRIPTION OF THE INVENTION

(10) The present invention, used in externally coated steel pipes in multi-layer systems for anti-corrosive protection and/or thermal isolation, preferably with an external diameter varying from 4 to 32 inches and with thicknesses varying from 6 to 51 mm (? to 2 inches), seeks to obtain gains associated with the useful life of the coated pipes when they are stored in the environment (open air), in addition to decreasing the assembly time, resulting in savings in the cost of construction, especially those costs related to the manufacturing process, storage, and assembly such as: (a) elimination of recurring losses due to corrosion in stored pipes; (b) reduction of the cost of sandblasting in the field; (c) elimination of the collar-brushing operation at the factory; (d) elimination of the operation of preparing an apparent range of the first layer (tail) at the factory; (e) reduction of the time to prepare the surface of the collar, decreasing the bottleneck in the release of seals in the field; and (f) mitigation of the environmental impact by reducing the area that is sandblasted in the field or on the vessel.

(11) The present invention refers to a system and method developed to protect coated pipes, preventing corrosion and mechanical damage on the ends/bevel, in the sandblasted area of the collar and internal surface, from storage to welding in the field or on the vessel, using the external coating itself and components specifically developed for that purpose.

(12) The mentioned system for protection of coated pipes for on-land and subsea pipelines allows the coating itself to be used as protection, and maintenance of the quality and surface roughness of the area of the collar (cutback) is obtained by means of its masking during the pipe-coating phase. Thus, the collar (cutback) is only exposed at the time of pipe assembly in the field or on the vessel.

(13) The fact that the protection is integrated into the pipe coating procedure improves the ability to seal the solution and allows the profile present on the end of the pipe (bevel) to be done at the pipe manufacturer's plants, making this process more economical and more traceable if compared to the current procedure, wherein this step is done in the field due to the inability of the current protective systems to guarantee the profile and the surface quality of the end of the pipe.

(14) Furthermore, brushing the coating in the factory can be eliminated, in order to maintain the roughness profile in the entire area until the time of assembly, thus avoiding the need to repeat the sandblasting operation in this area when in the field, so that the assembly that is comprised of the cup (1), spacer (2), coating (3), external ring (4), and cap (5) acts to prevent mechanical damage and corrosion on the ends and on the internal surface of the pipe.

(15) This invention therefore provides a system to protect pipes coated against corrosion internally and externally, protecting the ends/bevel against mechanical impacts, and that is capable of maintaining roughness in the area of the collar throughout the entire pipe coating process until its use in the field.

(16) The mentioned protective system is comprised of the following elements that interact amongst each other: a cup (1), a spacer (2), the external coating (3), an external ring (4), and a cap (5), all of which components are inserted throughout the coating process as it is currently performed, which was adapted, including with the insertion of new steps, in accordance with the method that is the scope of the present invention.

(17) The mentioned method of protecting pipes comprises the steps of: a) Attaching a protective cup (1) to the end of the pipe (6.1); b) Applying a coating to the pipe (3.1); c) Cutting the coating (3.1); d) Folding the coating envelope (3.2) over the cup (1); e) Attaching an external ring (4) to the cup (1) and on the folded part of the coating over the cup (1); and f) Attaching a cap (5) to the cup (1).

(18) The mentioned method may comprise an additional step of pre-heating, following the step of cleaning the pipe and prior to step a). This pre-heating step should be done at a temperature of 3? C. above the dew point and below 100? C.

(19) This method may also comprise an additional sandblasting step, following the cleaning and/or pre-heating step, and prior to step a).

(20) The sandblasting step is done in two sub-steps, in which the first sub-step is configured in order to clean the surface, and the second sub-step is configured to create a roughness profile at the end of the pipe that is between 60 and 100 ?m.

(21) The first sub-step preferentially uses round grit or a mixture of round and angular grit, and the second sub-step uses only angular grit.

(22) The mentioned method may also comprise an additional step of coupling and alignment of multiple pipes (6.1) prior to step a), as well as an additional step of heating the pipes (6.1) between 200? C. and 275? C. prior to step a), and the step of heating the pipes is done by electromagnetic induction.

(23) The mentioned method may further comprise an additional step of applying a resin on the pipe so that the electromagnetic induction also polarizes the pipe with a polarity that is inverse to that of the resin.

(24) Step b) must be done by extrusion of polymers, preferentially by means of co-extrusion, and more preferentially using polyethylene and polypropylene polymers.

(25) Step d) is done by means of the coating envelope (3), by means of folding it at a 90? C. to 180? C. angle over the cup (1).

(26) The method may further comprise an additional cooling step subsequent to step d), and an additional step of internal drying of the pipe prior to step f).

(27) The spacer (2) used during pipe coating, as an accessory item, should be reused in the coating process, noting that the coating (3) is used to protect the collar (cutback). Since the system is constructed throughout the coating method, the construction specifics in each phase will be pointed out, which contain adaptations related to use of the mentioned system:

(28) In Phase 2, Sandblasting, it is also necessary to use a closed bevel protector to prevent the bevel from being sandblasted, as it will be precision machined, and also to prevent grit from getting inside the pipe. This protector is reusable and should be removed after the pipe has been sandblasted.

(29) After Phase 3, Post-Sandblasting Inspection, a cup (1) is placed at each end of the pipe.

(30) Next, in Phase 4, Coupling and Alignment, the spacer (2) is placed between the anterior pipe and the posterior pipe, replacing the coupler. These operations, both placement of the cup (1) in Phase 3, as well as the spacer (2), may be done manually or it may be automated.

(31) The process continues normally until Phase 9, Cut and Separation, when the coating is cut, the spacer (2) is removed and returns to the production line in Phase 4.

(32) A new phase is added, called Coating Folding, which consists of folding the coating envelope (3) at an angle that is between 90 to 180? C., and placing the external ring (4). This phase may be performed after Phase 9 (Cutting and Separation) or in Phase 12 (Inspection of the Coating), at the criteria of the coater. Note that to perform it after Phase 9, the coater must alter its physical layout, so that the distance between the cutting location is increased, Phase 9, and the start of Cooling in Phase 10.

(33) In Phase 12, Inspection of the Coating, the pipe is dry inside, then the cap (5) is placed, and air is suctioned from inside the pipe through a safety valve (5.1), so that the pressure inside the pipe is lower than pressure outside the pipe. This pressure differential should be defined as a function of the diameter of the pipe, serving to maintain the cap's seal and prevent it from being expelled when the pressure inside is greater than the pressure outside. In this phase, Inspection of the Coating, the pipe is dry on the inside, the coating envelope is folded at an angle from 90 to 180? C., and the external ring (4) and the cap (5) will be placed, completing the process.

(34) Phase 13, Creation of the Collar and of the Tail, is eliminated, while Phases 14 (Final Inspection) and 15 (Placement of the Devices) are performed.

(35) The components of the system to protect coated pipes for on-land and subsea pipelines comprise:

(36) The cup (1), comprised of five main parts, as detailed in FIG. 2, has: an external tab (1.1), an internal surface of the external tab (1.2), an internal surface of the internal tab (1.3), sealing element (1.4), and a pressure ring (1.5). The cup (1) is mechanically connected to the pipe between the external portion of the pipe (6.1) and the coating (3).

(37) The purpose of the cup (1) is to mask the area of the pipe that will form the collar (cutback) and protect the bevel during the process of coating and transport. Its material may be metallic, polymeric, or composite.

(38) The co-polymeric adhesive used in the pipe coating process must adhere to the external surface of the external tab (1.1), and the internal diameter of the external tab (1.2) must be approximately equal to the external diameter of the pipe, with tolerance that allows it to be slotted in by intervention, so that it can be positioned without free movement during the coating process.

(39) The internal surface of the internal tab (1.3) has a sealing element (1.4) formed of one or more rings of polymeric or rubber material, preferentially neoprene, to prevent water from entering its interior during the cooling process.

(40) The length of the external tab (1.1) varies from 100 to 200 mm, and the length of the internal tab (1.3) varies from 50 to 200 mm, and the thickness of the wall of the cup (1) is less than or equal to 3 mm.

(41) The pressure ring (1.5) is made of metal or composite material, and it has a device to pressure the sealing element (1.4) against the internal wall of the pipe in order to ensure sealing during the cooling process and for its entire useful life. The pressure ring (1.5) also serves as a stopper for the cap (5) shown in FIG. 6.

(42) The function of the spacer (2), shown in FIG. 3, made of cast metal material, folded or welded, is to maintain adequate spacing and alignment between the pipes during coating. Its external diameter (2.1) is equal to the external diameter of the pipe to be coated, with tolerance of up to ?10 mm.

(43) With a chamfer (2.2) for cutting the coating, shown in FIG. 3, its surface (2.3) is rectified or machined with a degree of roughness that is lower than 20 ?m, in order not to allow adhesion of the first layer of epoxy.

(44) The spacer (2) is hollow (2.4) so that it is light, easy to manipulate, and to allow cooling water to enter into the pipe.

(45) The purpose of the coating (3) shown in FIG. 4 is to protect the collar (cutback), adhering to the external surface of the cup (1), and its envelope (3.1) will be folded (3.2) at an angle varying from 90? C. to 180? C. in order to prevent it from opening after removal of the spacer.

(46) The purpose of the external ring (4) shown in FIG. 5, used after removal of the spacer (2), is to affix the folded coating (3.2), creating a tab to protect the bevel (4.2). Its external diameter (4.5) is variable so that it can be slotted in by intervention in the internal diameter of the cup (1).

(47) The purpose of the cap (5) shown in FIG. 6 is to protect the inside of the pipe, and it is slotted into the component (1.5) of the cup (1). It is made of polymeric material or from a metal/polymer combination. The cap (5) has a safety relief valve (5.1), made of tin or stainless steel, attached to the surface of the cap (4) by a screw or intervention, and it is used for the pressure range seeking to alleviate the pressure inside the pipe when necessary.

(48) The external diameter (5.2) of the cap is equal to the internal diameter of the cup (1), and the mentioned cap also has a sealing system (5.3) to impede entry of any external means of oxidation, and furthermore, it has a handle (5.4) with a system to rapidly open and close the cap when necessary.

(49) Once the system for protecting coated pipes for on-land and subsea pipelines is assembled, the pipes are sent for use in the field, and the coating is cut by automation at an angle of less than 30? C., so that the system is removed quickly and precisely, either manually or by automation.

(50) FIG. 7 shows a view of the system to protect coated pipes for on-land and subsea pipelines assembled at the end of the assembly process, and FIG. 7 shows the mentioned system in an exploded perspective of the pipe after cutting and removing it.

(51) FIG. 8 details the pipe (6.1) prepared to be coupled and welded in the field or on the vessel after the coating is cut, and the entire assembly (6.2) relative to the pipe protection system is removed from the pipe after cutting and removing the cap (5).