System, machine and method for externally coating an annular joint portion of a pipe

Abstract

A machine for externally coating an annular joint portion of a pipe has an enveloping structure (11), which is configured to be closed around the pipe (1) so as to bound a closed chamber (12) around the annular joint portion (8) of the pipe (1) and to allow a rotation of the pipe (1) about a longitudinal axis (A1); at least one heating unit (13, 23), which is arranged within the enveloping structure (11) and is configured to heat the annular joint portion (8) during the rotation of the pipe (1) about the longitudinal axis (A1); and a spray unit (14), which is arranged within the enveloping structure (11) and is configured to apply a polymeric material to the annular joint portion (8) during the rotation of the pipe (1) about the longitudinal axis (A1).

Description

[0001] "SYSTEM, MACHINE AND METHOD FOR EXTERNALLY COATING AN

[0002] ANNULAR JOINT PORTION OF A PIPE"

[0003] Cross-Reference to Related Applications

[0004] This Patent Application claims priority from Italian Patent Application No . 102023000020772 filed on October 6 , 2023 , the entire disclosure of which is incorporated herein by reference .

[0005] Technical Field

[0006] The present invention relates to a system, a machine , and a method for externally coating an annular j oint portion of a pipe .

[0007] State of the Art

[0008] As is known, hydrocarbon transport pipes are made up of pipe sections that are j oined to each other . Typically, each pipe section has a length of approximately 12 meters and comprises a hollow metal cylinder, usually made of steel , on the outer surface of which protective coatings with anticorrosive and optionally thermal insulation, mechanical protection and weighting functions are generally applied . The stretches at the free ends of each pipe section are free of coating, which would otherwise be damaged by the heat produced during welding . Each of these uncoated stretches is called "cutback" .

[0009] The construction of a pipe in the field of installation, where the field is intended to mean an underwater or terrestrial field, is done by welding these pipe sections to form a seamless pipe called " string" . Once the weld has been made between two pipe sections , the coating of the cutback must be restored in the field . By way of example , document WO 2021 / 009709 describes a system for internally coating a pipe j oint in the field with a layer of polymeric material that combines the three functions of anti-corrosive protection, thermal insulation and mechanical protection .

[0010] In underwater fields , newly designed pipelaying vessels use a pre- fabrication area that allows a longer pipe section to be formed, which is a multiple of the standardlength pipe section . In particular , the pre- fabrication area feeds the launching line of the pipelaying vessel , where this multiple pipe section is welded to the string and then launched sequentially by the pipelaying vessel .

[0011] The creation and application in the field of the protective coating is called " Field Joint Coating" . The process of applying the protective coating involves preparing the surface of the annular j oint portion to a degree of finish compatible with the application of the coating materials . As a result , a plurality of operations on each annular j oint portion is required in accordance with the following sequence :

[0012] - sandblasting the annular j oint portion to remove impurities and oxidations from the surface of the annular j oint portion and giving a certain level of roughness to this surface , typically between 50 pm and 100 pm;

[0013] - pre-heating the annular j oint portion to a f irst temperature to facilitate the subsequent steps of application of polymeric materials ; applying a coating layer of polymeric material directly to the annular j oint portion; heating the annular j oint portion to a second temperature higher than the first temperature to cause complete cross-linking of the applied polymeric material .

[0014] Generally, the polymeric coating material comprises a base component and a hardener component . By way of example , the polymeric material may consist of a liquid, thermosetting two-component epoxy resin .

[0015] The term epoxy resin defines a thermosetting polymer, the formulation of which consists of two components : a base resin and a hardener component , which is a catalyst for the synthesis step called polymeri zation, which in the case of liquid resins takes place at temperatures ranging from 80 ° C to 175 ° C, depending on the speci fic product . As is known, there is a wide variety of base components and hardener components having physical , chemical and mechanical properties that can be adapted to a wide range of di f ferent applications .

[0016] Dedicated metering devices such as , for example , volumetric pumps or disposable pre-dosed kits , are often used to achieve the correct dosage of the base and hardener components . The mixing of the two components can be done by means of static mixers consisting of a cylindrical tube and fluid-dynamic traps . Due to a number of causes related to the fluid-dynamic start-up transitional phase , this mixing does not take place completely during the start-up phase . This leads to a secondary problem of waste of the initial polymeric material .

[0017] The chemical reaction leading to the cross-linking of the two components takes place in successive steps and results in an increase in the density of the polymeric material produced . This increase in density defines a useful workability time , called "pot-li fe" , before the base resin becomes hard and therefore no longer workable and unusable . In practice , the useful workability time depends on the temperature of the components : generally, as the temperature increases , the hardening speed of the base resin increases and the useful workability time decreases .

[0018] Document US 11278926 describes a machine for coating a weld of an annular j oint portion between two steel pipe sections . Said machine comprises a rail fixed circumferentially around the steel pipe near the annular j oint portion, a frame provided with a roller carriage configured to be slidably mounted on the rail , a spray unit provided with an arm arranged cantilevered in relation to the roller carriage and with a noz zle for dispensing polymeric material , which is coupled to one end of said arm, and a propulsion unit to control the sliding of the carriage along the rail and to move the arm and noz zle in the longitudinal direction in relation to the roller carriage .

[0019] However, the quality of the protective coating produced by the machine described in US 11278926 is not optimal . In particular, the protective coating layer made by the US 11278926 machine is poorly homogeneous along the entire annular j oint portion due to the influence of the force of gravity on the polymeric material dispensed by the spray unit . In practice , the protective coating layer has varying thickness and characteristics depending on the area of the annular j oint portion . By way of example , the thickness of the protective coating layer is maximum in an upper area of the annular j oint portion, and minimum in a lower area of the annular j oint portion . In addition, epoxy resins commonly used as protective coatings contain toxic volatile components . Accordingly, the present invention arises from the primary need to safeguard the health and safety of workers , allowing complete application of the polymeric material , without the operator coming into contact with the applied material and the fumes generated .

[0020] Moreover, even during prefabrication, a protective coating must be applied to the annular j oint portions between two consecutive pipe sections of the multiple pipe section to ensure an integral protective coating of the pipe .

[0021] Object of the Invention

[0022] One obj ect of the present invention is to provide a machine for externally coating an annular j oint portion of a pipe , which can mitigate the drawbacks of the prior art described herein .

[0023] In accordance with the present invention, a machine is provided for externally coating an annular j oint portion of a pipe extending along a longitudinal axis , the machine comprising :

[0024] - an enveloping structure , which is configured to be closed around the pipe so as to bound a closed chamber around the annular j oint portion of the pipe and to allow a rotation of the pipe about the longitudinal axis ;

[0025] - at least one heating unit , which is arranged within the enveloping structure and is configured to heat the annular j oint portion during the rotation of the pipe about the longitudinal axis ; and

[0026] - a spray unit , which is arranged within the enveloping structure and is configured to apply a polymeric material to the annular j oint portion during the rotation of the pipe about the longitudinal axis .

[0027] The present invention allows a protective coating to be applied to the annular j oint portion of a pipe in a simple , quick and safe manner .

[0028] In greater detai l , the machine provided in accordance with the present invention can be used during prefabrication on board a laying vessel and allows a j oint portion to be externally coated between two consecutive pipe sections of a multiple pipe section . The machine provided in accordance with the present invention can also be used on land for the fabrication of multiple pipe sections .

[0029] In practice , the protective coating can be applied to the annular j oint portion while keeping the heating unit and the spray unit substantially stationary and rotating the pipe about the longitudinal axis .

[0030] In addition, the enveloping structure allows the toxic volatile components of the sprayed polymeric material to be contained within a closed chamber, preventing said toxic components from being dispersed into the external environment .

[0031] In particular, the machine comprises at least one suction unit , which is arranged within the enveloping structure and is configured to suck gases and / or particulates within the closed chamber when the enveloping structure is closed around the pipe .

[0032] This allows the volatile components of the polymeric material to be evacuated from the inner chamber .

[0033] In particular, the polymeric material comprises a base component and a hardener component ; the machine comprising a mixer, preferably a static mixer, which is hydraulically connected to the spray unit and is configured to mix the base component and the hardener component so as to form the polymeric material , and a feeding system, which is configured to feed the base component to the mixer from a first interchangeable cartridge containing the base component and to feed the hardener component to the mixer from a second interchangeable cartridge containing the hardener component .

[0034] Furthermore , the feeding system comprises a first housing configured to house the first interchangeable cartridge , and a second housing configured to house the second interchangeable cartridge .

[0035] This allows the correct quantities of base component and hardener component to be prepared to produce enough polymeric material to externally coat a single annular j oint portion . In practice , the mixer can be fed with single-dose cartridges containing the base component and the hardener component for a single application of polymeric material .

[0036] In particular, the machine comprises a positioning mechanism configured to control the distance of the at least one heating unit and / or of the spray unit from the annular j oint portion of the pipe .

[0037] This allows the heating unit and / or the spray unit to be arranged at the correct distance to perform the operations for applying the polymer to the annular j oint portion . In practice , the positioning mechanism allows the external profile of irregularly shaped pipes , especially oval pipes , to be followed, compensating for any geometric errors and shape tolerances of the external profile of the pipes .

[0038] In accordance with one embodiment , the positioning mechanism comprises a base support arranged within the enveloping structure ; a tilting arm, which is hinged to the base support around a first rotation axis and carries the at least one heating unit and / or the spray unit ; and a first actuator configured to control a rotation of the ti lting arm around the first rotation axis .

[0039] In particular, the positioning mechanism comprises a second tilting arm, which is hinged to the base support around a second rotation axis substantially parallel to the first rotation axis ; and a connection body, which is connected to the at least one heating unit and / or to the spray unit and is hinged to the first and second tilting arms so as to reali ze a four-bar linkage mechanism together with the first and second tilting arms .

[0040] This allows the distance between the annular j oint portion and the heating unit and / or the spray unit to be adj usted in a simple and precise manner .

[0041] In particular, the machine comprises a collection tray, which is arranged within the enveloping structure and is configured to collect polymeric material purged from the spray unit .

[0042] During machine downtime , this prevents the polymeric material from solidi fying before being sprayed onto the annular j oint portion . In addition, during the transitional phases of the coating operations , the polymeric material that does not have the characteristics suitable for the application may be discarded .

[0043] In particular, the spray unit comprises a guide extending along a direction substantially parallel to the longitudinal axis of the pipe , and an applicator noz zle , which is configured to dispense the polymeric material and is slidable along said guide .

[0044] This allows the polymeric material to be dispensed, thereby covering the entire length of the annular j oint portion along a direction substantially parallel to the longitudinal axis of the pipe .

[0045] In particular, the enveloping structure comprises a base body; an upper cover, which is movable with respect to the base body between a closed position, in which the base body and the upper cover form a closed-ring enclosure , and an open position, in which the base body and the upper cover form an open-ring enclosure ; and an actuator configured to selectively move the upper cover between the open position and the closed position .

[0046] This allows the enveloping structure to be closed around an annular j oint portion, the annular j oint portion to be coated, and then the upper cover to be opened to allow the pipe to be pulled out of the enveloping structure . Once the coating operations have been completed, said operating steps can be repeated on a further annular j oint portion .

[0047] In particular, the machine comprises a centering mechanism, which supports the enveloping structure and is configured to adj ust the position of the enveloping structure with respect to the annular j oint portion of the pipe .

[0048] This allows the enveloping structure to be positioned around the annular j oint portion in a simple and precise manner .

[0049] A further obj ect of the present invention is to provide a system for externally coating an annular j oint portion of a pipe , which can mitigate the drawbacks of the prior art described herein .

[0050] In accordance with the present invention, a system is provided for externally coating an annular j oint portion of a pipe extending along a longitudinal axis , the system comprising :

[0051] - the machine as described above ; and

[0052] - a drive unit configured to control the rotation of the pipe about the longitudinal axis .

[0053] This allows the protective coating to be applied to the annular j oint portion while keeping the heating unit and the spray unit substantially stationary and controlling a rotation of the pipe about the longitudinal axis .

[0054] A further obj ect of the present invention is to provide a method for externally coating an annular j oint portion of a pipe , which mitigates the drawbacks of the prior art .

[0055] In accordance with the present invention, a method is provided for externally coating an annular j oint portion of a pipe extending along a longitudinal axis , the method comprising the steps of :

[0056] - closing an enveloping structure around the pipe so as to bound a closed chamber around the annular j oint portion of the pipe ;

[0057] - driving a rotation of the pipe about the longitudinal axis ;

[0058] - heating the annular j oint portion during the rotation of the pipe about the longitudinal axis ; and

[0059] - applying a polymeric material to the annular j oint portion during the rotation of the pipe about the longitudinal axis .

[0060] This method allows a protective coating to be applied to the annular j oint portion of a pipe in the field . In particular, the method allows the annular j oint portion of a pipe to be externally coated during the prefabrication phase carried out on board a laying vessel .

[0061] Brief Description of the Figures

[0062] Further features and advantages of the present invention will be apparent from the following description of preferred embodiments thereof , with reference to the Figures of the accompanying drawings , wherein :

[0063] - Figure 1 is a side elevation view, with parts in section and parts removed for clarity, of a partially externally coated pipe ;

[0064] - Figure 2 is a perspective view, with parts removed for clarity, of a system for externally coating an annular j oint portion of the pipe in Figure 1 , provided in accordance with the present invention;

[0065] - Figure 3 is a perspective view, with parts removed for clarity, of the system in Figure 2 in a further operating configuration;

[0066] - Figure 4 is a sectional view, with parts removed for clarity, of a machine of the system in Figure 2 ; and

[0067] - Figure 5 is a perspective view, with parts removed for clarity, of a detail of the machine of the system in Figure 2 ;

[0068] - Figure 6 is a side elevation view, with parts removed for clarity, of the detail in Figure 5 ; and

[0069] - Figures 7 and 8 are perspective views , with parts removed for clarity, of respective further details of the machine of the system in Figure 2 .

[0070] Detailed Description of the Figures With reference to Figure 1 , number 1 indicates , as a whole , a pipe to be coated, which extends along a longitudinal axis Al .

[0071] In the case described and illustrated herein, the pipe

[0072] 1 comprises two pipe sections 2 aligned along the longitudinal axis Al . Each pipe section 2 comprises a metal cylinder 3 and a coating 4 , preferably an anti-corrosive coating made of polymeric material , which is arranged in contact with the metal cylinder 3 and has the function of protecting the metal cylinder 3 from corrosion .

[0073] By way of example , the coating 4 can be made of a polymeric material comprising a base component and a hardener component such as , for example , a two-component , thermosetting epoxy resin with a high viscosity . In greater detail , the coating 4 can be made from a single anticorrosive layer, e . g . epoxy- or polyurethane-based, or from a multi-layer comprising an anti-corrosive layer, an adhesive layer, and a coating layer with a mechanical protection function .

[0074] Each pipe section 2 has two opposite free ends 5 ( only one of which is shown in Figure 1 ) without the coating 4 , which has a chamfer 6 at each free end 5 . Two successive pipe sections 2 aligned along the longitudinal axis Al are arranged with the free ends 5 facing each other and are welded in such a way that an annular weld bead 7 is made between the two pipe sections 2 . The two welded pipe sections

[0075] 2 define an annular j oint portion 8 , which extends along the longitudinal axi s Al between the two chamfers 6 of the coating 4 and comprises the annular weld bead 7 .

[0076] The pipe 1 is formed by j oining the pipe sections 2 . With reference to the present description, the pipe 1 also refers to the pipe in the construction phase , which may consist , for example , of only two pipe sections 2 j oined together .

[0077] With reference to Figures 2 and 3 , reference 9 indicates , as a whole , a system for externally coating the annular j oint portion 8 of the pipe 1 .

[0078] The system 9 can be used on board a laying vessel during pre- fabrication of the pipe 1 , in particular, to externally coat an annular j oint portion 8 of a multiple pipe section, without thereby limiting the wide range of applications of the present invention . It is understood that the system 9 can also be used to coat any annular j oint portion of a rotating pipe regardless of the installation site or construction phase .

[0079] The system 9 comprises a machine 10 comprising :

[0080] - an enveloping structure 11 , which is configured to be closed around the pipe 1 so as to bound a closed chamber 12 around the annular j oint portion 8 and to allow a rotation of the pipe 1 about the longitudinal axis Al ; a heating unit 13 , which is arranged within the enveloping structure 11 and is configured to heat the annular j oint portion 8 during the rotation of the pipe 1 about the longitudinal axis Al ; and a spray unit 14 , which is arranged within the enveloping structure 11 and is configured to apply a polymeric material to the annular j oint portion 8 during the rotation of the pipe 1 about the longitudinal axis Al .

[0081] In particular, the spray unit 14 is configured to apply the polymeric material in the liquid form to the annular j oint portion 8 .

[0082] Moreover, the system 9 comprises a drive unit 15 configured to control the rotation of the pipe 1 about the longitudinal axis Al .

[0083] In particular, the drive unit 15 comprises a motorised roller assembly 16 configured to drive the rotation of the pipe 1 about the longitudinal axis Al .

[0084] The system 9 further comprises a control unit 17 configured to coordinately control the heating unit 13 , the spray unit 14 and the drive unit 15 .

[0085] In particular, the enveloping structure 11 comprises a base body 18 ; an upper cover 19 , which is movable with respect to the base body 18 between a closed position ( Figure 2 ) , in which the base body 18 and the upper cover 19 form a closed-ring enclosure , and an open position ( Figure 3 ) , in which the base body 18 and the upper cover 19 form an openring enclosure ; and an actuator 20 configured to selectively move the upper cover 19 between the open position and the closed position .

[0086] In the non-limiting case of the present invention described and illustrated herein, the base body 18 and the upper cover 19 extend along respective annular portions .

[0087] In greater detail , the upper cover 19 is hinged to the base body 18 around a rotation axis A2 , and the actuator 20 is configured to act between the base body 18 and the upper cover 19 to drive a rotation of the upper cover 19 around the rotation axis A2 . In this case , the actuator 20 is a hydraulic cylinder .

[0088] With reference to Figure 3 , the base body 18 comprises two side walls 21 , and the upper cover 19 comprises two side walls 22 . Each side wall 21 , 22 is made of a flexible material and is shaped to follow the circumferential profile of the pipe 1 and to contact the outer surface of the pipe 1 so as to bound the closed chamber 12 ( Figure 2 ) around the annular j oint portion 8 when the enveloping structure 11 is arranged around the pipe 1 .

[0089] In particular, each side wall 21 , 22 is configured to slide on the outer surface of the pipe 1 when the pipe 1 rotates about the longitudinal axis Al within the enveloping structure 11 .

[0090] With reference to Figure 4 , the machine 10 comprises a heating unit 23 arranged within the enveloping structure 11 in a diametrically opposite position to the heating unit 13 .

[0091] In particular, each heating unit 13 , 23 is used for pre-heating the annular j oint portion 8 and / or then polymeri zing the polymeric product applied to the annular j oint portion 8 .

[0092] In greater detail , each heating unit 13 , 23 comprises a heating element such as , for example , an induction coil or an electrical resistor .

[0093] In accordance with one embodiment , the machine 10 comprises a suction unit 24 and a suction unit 25 , each of which is arranged within the enveloping structure 11 and is configured to suck gases and / or particulates within the closed chamber 12 when the enveloping structure 11 is closed around the pipe 1 .

[0094] In particular, the suction unit 24 is arranged in a lower portion of the base body 18 , and the suction unit 25 is arranged in an upper portion of the base body 18 .

[0095] In accordance with one embodiment , the machine 10 comprises an evacuation unit , not shown in the attached Figures , which is connected to the suction unit 24 and / or the suction unit 25 and is configured to convey the gases sucked by the suction unit 24 and / or the suction unit 25 to an exhaust outside the closed chamber 12 .

[0096] Furthermore , the machine 10 comprises a collection tray 26 , which is arranged within the enveloping structure 11 and is configured to collect polymeric material purged from the spray unit 14 . Said purging takes place automatically, without any intervention by an operator, and is necessary in order to remove the residual polymeric material that has not yet had the opportunity to mix . In particular, the collection tray 26 is arranged under the spray unit 14 .

[0097] In the non-limiting case of the present invention described and illustrated herein, the machine 10 comprises a positioning mechanism 27 configured to control the distance of the heating unit 13 and / or of the spray unit 14 from the annular j oint portion 8 of the pipe 1 .

[0098] Moreover, the machine 10 comprises a positioning mechanism 28 configured to control the distance of the heating unit 23 from the annular j oint portion 8 of the pipe 1 . In particular, the positioning mechanisms 27 and 28 are coupled to the base body 18 on opposite sides of the longitudinal axis Al .

[0099] With reference to Figures 4 and 5 , the positioning mechanism 27 comprises a base support 29 arranged within the enveloping structure 11 ; a tilting arm 30 , which is hinged to the base support 29 around a rotation axis A3 and carries the heating unit 13 and the spray unit 14 ; and an actuator 31 configured to control a rotation of the tilting arm 30 around the rotation axis A3 .

[0100] In particular, the positioning mechanism 27 comprises a tilting arm 32 , which is hinged to the base support 29 around a rotation axis A4 substantially parallel to the rotation axis A3 ; and a connection body 33 , which is connected to the heating unit 13 and to the spray unit 14 and is hinged to the tilting arms 30 and 32 so as to reali ze a four-bar linkage mechanism together with the tilting arms 30 and 32 . In practice , the tilting arms 30 and 32 extend along respective substantially parallel directions .

[0101] With reference to Figure 4 , the positioning mechanism 28 comprises a base support 34 arranged within the enveloping structure 11 ; a tilting arm 35 hinged to the base support 34 around a rotation axis A5 ; a tilting arm 36 hinged to the base support 34 around a rotation axis A6 substantially parallel to the rotation axis A5 ; a connection body 37 , which is connected to the heating unit 23 and is hinged to the tilting arms 35 and 36 so as to reali ze a four-bar linkage mechanism together with the tilting arms 35 and 36 ; and an actuator (not visible in Figure 4 ) configured to control a rotation of the tilting arm 35 around the rotation axis A5 .

[0102] With reference to Figure 5 , the spray unit 14 comprises a guide 39 extending along a direction substantially parallel to the longitudinal axis Al of the pipe 1 , and an applicator noz zle 40 , which is configured to dispense the polymeric material and is slidable along the guide 39 .

[0103] In accordance with one embodiment not shown in the attached Figures , the spray unit 14 comprises two applicator noz zles 40 which can slide along the guide 39 .

[0104] In addition, the spray unit 14 comprises an actuator assembly, not shown in the attached Figures, which is configured to control the sliding of the applicator nozzle 40 along the guide 39.

[0105] With reference to Figure 6, the spray unit 14 comprises a tilt mechanism 61 configured to adjust the tilt of the applicator nozzle 40.

[0106] In particular, the tilt mechanism 61 is configured to control a rotation of the applicator nozzle 40 around a rotation axis A7 substantially parallel to the longitudinal axis Al between an application position and a purge position.

[0107] In greater detail, in the application position, the applicator nozzle 40 faces the annular joint portion 8 of the pipe 1. In the purge position, the applicator nozzle 40 faces the collection tray 26.

[0108] With reference to Figure 7, the machine 10 comprises a centering mechanism 41, which supports the enveloping structure 11 and is configured to adjust the position of the enveloping structure 11 with respect to the annular joint portion 8 of the pipe 1.

[0109] In particular, the centering mechanism 41 comprises a plurality of rails 42 extending along a direction substantially parallel to the longitudinal axis Al; a carriage 43 configured to slide along the rails 42; a support element 44, which is coupled to the enveloping structure 11; and a lifting system 45, which is carried by the carriage 43, supports the support element 44 and is configured to control the position of the support element 44 in a substantially vertical direction.

[0110] In greater detail, the base body 18 of the enveloping structure 11 (Figures 2-4) is slidably coupled to the support element 44 along a substantially perpendicular direction with respect to the longitudinal axis Al and to the vertical direction .

[0111] In practice , the centering mechanism 41 is configured to adj ust the distance of the enveloping structure 11 from the ground, adj ust the position of the enveloping structure 11 along the longitudinal axis Al of the pipe 1 and adj ust the position of the enveloping structure 11 in a direction perpendicular to the longitudinal axis Al and the vertical direction .

[0112] In greater detail , the li fting system 45 comprises two li fting units 47 , each comprising a movable arm 48 and a movable arm 49 hinged together at respective central portions , and an actuator 50 , in particular a hydraulic cylinder, which acts between the carriage 43 and the movable arms 48 and 49 to adj ust the tilt of the movable arms 48 and 49 . In particular, each movable arm 48 , 49 has a first end hinged to the carriage 43 and a second end hinged to the support element 44 .

[0113] In the non-limiting case of the present invention described and illustrated herein, the support element 44 comprises a guide 51 , which extends in a direction substantially perpendicular to the longitudinal axis Al and the vertical direction . The base body 18 ( Figures 2-4 ) is configured to slide along the guide 51 .

[0114] With reference to Figure 8 , the machine 10 comprises a mixer (not shown in the attached Figures ) , which is hydraulically connected to the spray unit 14 ( Figures 2- 6 ) and is configured to mix the base component and the hardener component so as to form the polymeric material ; and a feeding system 55 , which is configured to feed the base component to the mixer from an interchangeable cartridge 56 containing the base component and to feed the hardener component to the mixer from an interchangeable cartridge 57 containing the hardener component .

[0115] In accordance with a non-limiting embodiment of the present invention, said mixer is of the static type and comprises a labyrinth mixing portion .

[0116] In particular, the feeding system 55 comprises a housing 58 configured to house the interchangeable cartridge 56 , and a housing 59 configured to house the interchangeable cartridge 57 .

[0117] In greater detai l , the housings 58 and 59 are coupled to the enveloping structure 11 , outside the closed chamber 12 . Thus , the housings 58 and 59 are easily accessible for a person in charge of assembling the pipe 1 , who can replace the used cartridges 56 and 57 with new cartridges 56 and 57 in a simple and quick way .

[0118] In addition, the feeding system 55 comprises an actuator assembly 60 , in particular of the pneumatic type , which is configured to extract the base component from the interchangeable cartridge 56 and the hardener component from the interchangeable cartridge 57 and to push the extracted base component and the extracted hardener component towards the spray unit 14 through the mixer . In particular, the actuator assembly 60 is configured to extract the base component from the interchangeable cartridge 56 and the hardener component from the interchangeable cartridge 57 synchronously . This allows the mixing ratio between the base component and the hardener component to be kept constant . In use , the machine 10 carries out processing cycles on the annular j oint portions 8 of the pipe 1 , each of which involves coupling to the pipe 1 around an annular j oint portion 8 , spraying the polymeric material onto the annular j oint portion 8 , heating the annular j oint portion 8 , and decoupling from the pipe 1 .

[0119] With reference to Figure 3 , the as sembly of the pipe 1 involves feeding the pipe 1 stepwise in a direction parallel to the longitudinal axis Al and coupling the machine 10 around the pipe 1 at the annular j oint portion 8 .

[0120] In greater detail , the pipe 1 slides along the longitudinal axi s Al until the annular j oint portion 8 is arranged within the enveloping structure 11 .

[0121] With reference to Figure 2 , the actuator 20 drives the rotation of the upper cover 19 around the rotation axis A2 , so that the upper cover 19 moves from the open position to the closed position . In the closed position, the enveloping structure 11 bounds the closed chamber 12 around the annular j oint portion 8 of the pipe 1 .

[0122] At this point , the centering mechanism 41 adj usts the position of the enveloping structure 11 in relation to the annular j oint portion 8 of the pipe 1 . In particular, the centering mechanism 41 adj usts the distance of the enveloping structure 11 from the ground, the position of the enveloping structure 11 along the longitudinal axis Al of the pipe 1 , and the position of the enveloping structure 11 in a direction perpendicular to the longitudinal axis Al and the vertical direction .

[0123] With reference to Figure 8 , a person in charge of assembling the pipe 1 removes any used interchangeable cartridges 56 , 57 from the respective housings 58 , 59 , and houses other cartridges 56 and 57 in the respective housings 58 , 59 .

[0124] With reference to Figures 4- 6 , the positioning mechanism 27 controls the rotation of the tilting arm 30 in order to adj ust the distance of the heating unit 13 and the spray unit 14 from the annular j oint portion 8 of the pipe 1 . In addition, the tilt mechanism 61 controls the rotation of the applicator noz zle 40 around the rotation axis A7 from the purge position to the application position .

[0125] At this point , with reference to Figure 2 , the motorised roller assembly 16 drives the rotation of the pipe 1 about the longitudinal axis Al .

[0126] With reference to Figure 8 , during the rotation of the pipe 1 , the feeding system 55 feeds the base component and the hardener component from the respective interchangeable cartridges 56 , 57 to the mixer and feeds the polymeric material from the mixer to the spray unit 14 . The applicator noz zles 40 spray the fed polymeric material onto the annular j oint portion 8 , while the applicator noz zles 40 slide along the guide 39 so as to cover the entire length of the annular j oint portion 8 along the longitudinal axis Al with a layer of polymeric material .

[0127] With reference to Figure 4 , the suction unit 24 is automatically activated when the applicator noz zles 40 spray the fed polymeric material onto the annular j oint portion 8 and remains active until the application of the polymeric material onto the annular j oint portion 8 is finished .

[0128] Once the application of the polymeric material is finished, the heating units 13 and 23 heat the applied layer of polymeric material to facilitate the polymeri zation of the applied polymeric material . At the same time , the suction unit 25 is activated automatically and remains active for a speci fied time , even after the end of the heating of the applied layer of polymeric material .

[0129] In accordance with one embodiment , for the application of liquid epoxy resins , the heating units 13 and 23 are generally activated before and after the application of the polymeric material to the annular j oint portion 8 . It is understood that the machine 10 can be set up to perform di f ferent spray cycles , combined with the activation of the heating units 13 and 23 , speci fic for the type of polymeric material applied .

[0130] The positioning mechanism 27 then moves the heating unit 13 and the spray unit 14 away from the annular j oint portion 8 , and the actuator 20 drives the rotation of the upper cover 19 around the rotation axis A2 , so as to move the upper cover 19 from the closed position to the open position and allow the annular j oint portion 8 to be removed from the enveloping structure 11 .

[0131] It is understood that variations may be made to the present invention without however departing from the scope of protection of the appended claims .

Claims

CLAIMS1. A machine for externally coating an annular joint portion of a pipe extending along a longitudinal axis, the machine (10) comprising:- an enveloping structure (11) , which is configured to be closed around the pipe (1) so as to bound a closed chamber (12) around the annular joint portion (8) of the pipe (1) and to allow a rotation of the pipe (1) about the longitudinal axis (Al) ;- at least one heating unit (13, 23) , which is arranged within the enveloping structure (11) and is configured to heat the annular joint portion (8) during the rotation of the pipe (1) about the longitudinal axis (Al) ; and a spray unit (14) , which is arranged within the enveloping structure (11) and is configured to apply a polymeric material to the annular joint portion (8) during the rotation of the pipe (1) about the longitudinal axis (Al) .

2. The machine as claimed in Claim 1, and comprising at least one suction unit (24, 25) , which is arranged within the enveloping structure (11) and is configured to suck gases and / or particulates within the closed chamber (12) when the enveloping structure (11) is closed around the pipe (1) .

3. The machine as claimed in Claim 1 or 2, wherein the polymeric material comprises a base component and a hardener component; the machine (10) comprising a mixer, preferably a static mixer, which is hydraulically connected to the spray unit (14) and is configured to mix the base component and the hardener component so as to form the polymeric material, and a feeding system (55) , which is configured to feed the base component to the mixer from a first interchangeablecartridge (56) containing the base component and to feed the hardener component to the mixer from a second interchangeable cartridge (57) containing the hardener component.

4. The machine as claimed in Claim 3, wherein the feeding system (55) comprises a first housing (58) configured to house the first interchangeable cartridge (56) , and a second housing (59) configured to house the second interchangeable cartridge (57) .

5. The machine as claimed in any one of the foregoing Claims, and comprising a positioning mechanism (27, 28) configured to control the distance of the at least one heating unit (13, 23) and / or of the spray unit (14) from the annular joint portion (8) of the pipe (1) .

6. The machine as claimed in Claim 5, wherein the positioning mechanism (27, 28) comprises a base support (29, 34) arranged within the enveloping structure (11) ; a first tilting arm (30, 35) , which is hinged to the base support (29, 34) around a first rotation axis (A3, A5) and carries the at least one heating unit (13, 23) and / or the spray unit (14) ; and a first actuator (31) configured to control a rotation of the first tilting arm (30, 35) around the first rotation axis (A3, A5) .

7. The machine as claimed in Claim 6, wherein the positioning mechanism (27, 28) comprises a second tilting arm (32, 36) , which is hinged to the base support (29, 34) around a second rotation axis (A4, A6) substantially parallel to the first rotation axis (A3, A5) ; and a connection body (33, 37) , which is connected to the at least one heating unit (13, 23) and / or to the spray unit (14) and is hinged to the first tilting arm (30, 35) and to the second tilting arm (32, 36) so as to realize a four-bar linkage mechanismtogether with the first tilting arm (30, 35) and second tilting arm (32, 36) .

8. The machine as claimed in any one of the foregoing Claims, and comprising a collection tray (26) , which is arranged within the enveloping structure (11) and is configured to collect polymeric material purged from the spray unit ( 14 ) .

9. The machine as claimed in any one of the foregoing Claims, wherein the spray unit (14) comprises a guide (39) extending along a direction substantially parallel to the longitudinal axis (Al) of the pipe (1) , and an applicator nozzle (40) , which is configured to dispense the polymeric material and is slidable along said guide (39) .

10. The machine as claimed in Claim 9, wherein the spray unit (14) comprises two applicator nozzles (40) slidable along said guide (39) .

11. The machine as claimed in any one of the foregoing Claims, wherein the enveloping structure (11) comprises a base body (18) ; an upper cover (19) , which is movable with respect to the base body (18) between a closed position, in which the base body (18) and the upper cover (19) form a closed-ring enclosure, and an open position, in which the base body (18) and the upper cover (19) form an open-ring enclosure; and a second actuator (20) configured to selectively move the upper cover (19) between the open position and the closed position.

12. The machine as claimed in any one of the foregoing Claims, and comprising a centering mechanism (41) , which supports the enveloping structure (11) and is configured to adjust the position of the enveloping structure (11) with respect to the annular joint portion (8) of the pipe (1) .

13. The machine as claimed in Claim 12, wherein the centering mechanism (41) comprises a rail (42) extending along a direction substantially parallel to the longitudinal axis (Al) ; a carriage (43) configured to slide along said rail (42) ; a support element (44) , which is coupled to the enveloping structure (11) ; and a lifting system (45) , which is carried by the carriage (43) , supports the support element (44) and is configured to control the position of the support element (44) in a substantially vertical direction.

14. The machine as claimed in Claim 13, wherein the enveloping structure (11) is slidably coupled to the support element (44) along a substantially perpendicular direction with respect to the longitudinal axis (Al) and to the vertical direction.

15. A system for externally coating an annular joint portion of a pipe extending along a longitudinal axis, the system (9) comprising: the machine (10) as claimed in any one of the foregoing Claims; and- a drive unit (15) configured to control the rotation of the pipe (1) about the longitudinal axis (Al) .

16. The system as claimed in Claim 15, wherein the drive unit (15) comprises a motorised roller assembly (16) configured to drive the rotation of the pipe (1) about the longitudinal axis (Al) .

17. The system as claimed in Claim 15 or 16, and comprising a control unit (17) configured to coordinately control the heating unit (13) , the spray unit (14) and the drive unit ( 15) .

18. A method for externally coating an annular joint portion of a pipe extending along a longitudinal axis, themethod comprising the steps of:- closing an enveloping structure (11) around the pipe (1) so as to bound a closed chamber (12) around the annular joint portion (8) of the pipe (1) ; driving a rotation of the pipe (1) about the longitudinal axis (Al) ;- heating the annular joint portion (8) during the rotation of the pipe (1) about the longitudinal axis (Al) ; and- applying a polymeric material to the annular joint portion (8) during the rotation of the pipe (1) about the longitudinal axis (Al) .

19. The method as claimed in Claim 18, and comprising the step of sucking gases and / or particulates within the closed chamber (12) when the enveloping structure (11) is closed around the pipe (1) .

20. The method as claimed in Claim 18 or 19, wherein the polymeric material comprises a base component and a hardener component; the method comprising the steps of mixing the base component and the hardener component by means of a mixer so as to form the polymeric material; feeding the base component to the mixer from a first interchangeable cartridge (56) containing the base component; and feeding the hardener component to the mixer from a second interchangeable cartridge (57) containing the hardener component.

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