CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no . 102020000023206 filed on 01 / 10/2020 , the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention relates to a laying vessel for laying pipelines on a bed of a body of water .

In particular, the present invention relates to a laying vessel comprising a floating structure and a laying tower hinged to the floating structure and configured to assemble and lay a pipeline on the bed of the body of water .

PRIOR ART

Laying vessels with the characteristics identi fied above are described in the following documents : WO 2009/ 082191 Al ; WO 2009/ 145607 Al ; and WO 01 / 07812 Al .

Sometimes it is necessary to apply bulky elements , in particular thrust modules , around the pipeline during assembly before laying . By way of example , the thrust modules can be applied to a pipeline connecting a fixed structure laid on the seabed and an anchored floating structure , which moves around the mooring position . This type of pipeline is called riser, which, in a particular configuration, forms two catenaries interspersed with an arch supported by the thrust modules .

Other types of pipelines , such as spanned flowline or trunkline pipelines , also require the application of bulky elements around the pipeline , which can be thrust modules , sensors , actuators , heating elements or modules fitted with fins arranged in a helical pattern, the function of which is to reduce the vibrations induced on the pipeline by weather conditions , mainly currents .

Document WO 2009/ 153352 describes a pipe-laying vessel configured to bring to the laying line and to weld bulky elements on a pipeline and comprising a laying tower ; a loading arm for li fting sections of pipe from the deck of the vessel up to a position aligned with the tower ; and a support assembly for supporting a bulky element to be applied around the pipeline , wherein the support assembly comprises a frame which can be inclined between a first position for receiving the bulky element and a second inclined position in which it extends parallel to the tower, and actuation means for allowing the rotation of the tiltable frame between the first and second position .

At present , the application of bulky elements involves a step of clamping the bulky element around the pipeline by workers , who work in the limited spaces of the laying tower and under heavy loads .

Furthermore , with the system described in WO 2009/ 153352 the coverage of bulky elements around the pipeline is reduced, due to the arrangement of the bulky module loading station above the welding station of the pipeline sections . This arrangement prevents the entire length of the pipeline from being covered with the bulky elements applied around the pipeline , and the maximum length of the bulky elements is limited, as the bulky element loading station must be safely accessible to workers .

DISCLOSURE OF INVENTION One aim of the present invention is to reali ze a manipulator device which mitigates the drawbacks of the prior art , in a simple way and without substantial alterations in the configuration of the laying tower .

According to the present invention, a manipulator device is reali zed in order to apply modules around a pipeline during assembly, wherein each module comprises two portions configured to enclose a section of pipeline ; the manipulator device comprising two j aws mobile between an open and a closed position and configured to house the respective portions of the module , and an articulated mechanism having a plurality of degrees of freedom to place the j aws in a loading position and in a position wherein the aws are aligned with the pipeline during assembly .

Thanks to the present invention, it is possible to apply modules around the pipeline during assembly in an automated manner, making laying operations faster and guaranteeing the safety of the workers involved in the laying operations .

In addition, the present invention enables the modules to be applied seamlessly to the pipeline, so that the pipeline section can be completely coated quickly .

In particular, the mechanism comprises a base body; and an arm, which is hinged to the base body around a first rotation axis and is selectively mobile around the first rotation axis , to adj ust the inclination of the arm so as to align the j aws with the pipeline section to which the modules are to be applied .

In particular, the mechanism comprises a slide , which is coupled to the arm and the j aws and is configured to selectively move the j aws with respect to the arm in a first direction, so as to precisely adj ust the longitudinal position of the j aws with respect to the pipeline section to which the modules are to be applied .

In particular, the mechanism comprises a first elongated body, which extends along a first longitudinal axis substantially parallel to the first direction, is coupled to the slide and supports the two j aws in a mobile manner between an open and a closed position .

Thanks to the first elongated body, the aws can be placed in the desired position .

In particular, the mechanism comprises an adj usting device , which is configured to adj ust the inclination of the j aws around a second rotation axis substantially parallel to the first rotation axis when the j aws are in proximity to said pipeline section .

In this way, it is possible to precisely copy the inclination of the pipeline section to which the module is to be applied, following the movement of the floating structure and the oscillations of the laying tower .

In particular, each j aw comprises a frame , which is hinged to the first elongated body around a rotation axis substantially parallel to the first longitudinal axis , so as to allow the respective j aw to be opened and closed .

In greater detail , the frame comprises a second elongated body, which extends along a second longitudinal axis substantially parallel to the first longitudinal axis ; and two transverse elements , which are fixed to the second elongated body at a distance from each other and are configured to accommodate respective portions of the module . In this way, the second elongated body and the transverse elements delimit a hous ing seat for the portions of module .

In particular, each j aw comprises at least one preloading cylinder, which is coupled to the respective second elongated body and is configured to push the respective portion of module against the pipeline section when the aws are in closed position around the pipeline section, so as to cause a radial preload on the portions of module .

In particular, each j aw comprises respective gripping belts , which are configured to accommodate and selectively hold respective portions of module .

Thanks to the gripping belts , it is possible to hold the portions of module on the respective j aws when placing the j aws around the pipeline during assembly, and to release the portions of module after they have been applied to the pipeline .

In particular, each j aw comprises at least one automatic screwdriver, which is carried by the respective j aw and is configured to screw together two respective portions of module .

In this way, the portions of module are screwed together in an automated manner, avoiding the use o f labour for said operations . A further aim of the present invention is to reali ze a laying vessel that mitigates the drawbacks of the prior art , in a simple manner and without substantial alterations in the configuration of the laying tower .

According to the present invention, a laying vessel for laying pipelines on a bed of a body of water is reali zed; the laying vessel comprising a floating structure ; a laying tower, which is hinged to the floating structure around a third rotation axis , defines a laying line , and is configured to assemble and lay a pipeline on the bed of the body of water ; and the manipulator device as previously described .

In this way, it is possible to lay a pipeline on the bed of a body of water simply, quickly and safely, as the workers responsible for the operations of applying the modules around the pipeline work outside the laying tower .

In particular, the laying tower comprises a clamping assembly, which is configured to clamp and advance the pipeline section and comprises a first clamping unit fixed to the laying tower and a second clamping unit , which is arranged in series with respect to the first clamping unit and is mobile along the laying line between a first position, at a first di stance from the first clamping unit , and a second position, at a second distance from the first clamping unit , wherein the first distance is greater than the second distance ; the manipulator device being configured to apply the modules around the pipeline section comprised between the first and second clamping unit .

In this way, it is possible to apply the module to the pipeline section comprised between the two clamping units and subsequently lay the pipeline section to which the module has been applied .

In accordance with a particular embodiment of the present invention, the laying vessel comprises a li fting frame configured to support at least one portion of the module ; and a crane , which is configured to li ft the li fting frame and is equipped with an adj ustable gripping tool , which is configured to adj ust the position and/or the inclination of the li fting frame with respect to the manipulator device so as to place each portion of the module in the respective j aw when the j aws are in the loading position .

In this way, the position and the inclination of the li fting frame with respect to the manipulator device can be adj usted to follow the movements of the laying vessel .

A further aim of the present invention is to reali ze a method to operate a laying vessel which mitigates the drawbacks of the prior art .

According to the present invention, a method to operate a laying vessel is realized; the laying vessel comprising a floating structure ; a laying tower, which is hinged to the floating structure around a third rotation axis , defines a laying line , and is configured to assemble and lay a pipeline on the bed of a body of water ; the method comprising the steps of placing two j aws in a loading position; accommodating each portion of a module in the respective j aw; placing the two j aws in a position wherein the j aws are aligned with the pipeline during assembly; and closing the two j aws around a section of said pipeline .

Thanks to this method, it is possible to apply modules around the pipeline during assembly in an automated, simple and fast manner, avoiding the presence of workers involved in the operations of applying the modules in the laying tower . In this way, it is possible to increase the ef ficiency of pipeline-laying operations and, at the same time , to guarantee an adequate level of safety for the workers involved in the laying operations .

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become clear from the following description of a non-limiting example of an embodiment thereof , with reference to the Figures of the attached drawings , in which : - Figure 1 is a side elevation view, with schematic parts and parts removed for clarity' s sake , of a laying vessel reali zed in accordance with the present invention;

- Figure 2 is a perspective view of a thrust module applicable to a pipeline by means of the laying vessel of Figure 1 ;

Figures 3 and 4 are perspective views of a manipulator device of the laying vessel of Figure 1 in respective operating configurations ;

- Figure 5 is a front view of the manipulator device of the laying vessel of Figure 1 ;

Figure 6 is a side elevation view of the manipulator device of the laying vessel of Figure 1 ; and

Figures 7- 10 are side elevation views , with schematic parts and parts removed for clarity' s sake , of the manipulator device of the laying vessel of Figure 1 in respective operating configurations .

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figure 1 , number 1 overall denotes a laying vessel for laying a pipeline 2 on a bed (not shown) of a body of water 3 .

The laying vessel 1 comprises a floating structure 4 ; a laying tower 5 , which defines a laying line 6 and is configured to assemble and lay the pipeline 2 on the bed of the body of water 3 ; and a manipulator device 7 to apply modules 8 to the pipeline 2 during assembly .

With reference to Figure 2 , the modules 8 comprise two hollow semi-cylindrical portions 9 that can be coupled together and are configured to determine an upward hydrostatic thrust on the pipeline 2 .

In this regard, each portion 9 may be made by roto- moulding and the hollow volume of each portion 9 may be filled with lightening material , for example syntactic spheres , special resins or foams , adapted to ensure an adequate upward hydrostatic thrust and to withstand the operating pressures in the body of water 3 .

Furthermore , in the case described and shown herein, which is not limiting to the present invention, the modules 8 are configured to prevent wake vortices from detaching from the pipeline 2 when the pipeline 2 is arranged in the body of water 3 .

This vortex detachment phenomenon is caused by a water current incident to the pipeline 2 , and can cause oscillations of the pipeline 2 induced by said vortices (Vortex Induced Vibration) . When the detachment frequency of the vortexes (Vortex Shedding) that are generated at the rear of the pipel ine 2 with respect to the direction of the current is close to a natural frequency of the pipeline 2 , the induced oscillations are ampli fied, stressing the structure of the pipeline 2 with fatigue . In order to mitigate these drawbacks , in the case described and shown herein, each module 8 is equipped with hydrodynamic fins 10 , which are arranged in a helical profile on the outer cylindrical face of the respective module 8 .

Said hydrodynamic fins 10 reduce the phenomenon of detachment of the alternating vortexes thanks to a vorticity imposed on the water current by appropriate pitch and diameter ratios of the helical profile .

With reference to Figure 1 , the floating structure 4 has a hull 11 , an open deck 12 ; a stern 13 ; and a bow, not shown in the attached Figures .

In the case described and shown herein, the laying tower 5 is mounted at the stern 13 and is hinged around a rotation axis Al to selectively arrange the laying tower 5 between a plurality of operating positions , having respective inclinations with respect to the open deck 12 .

In this way, the laying tower 5 can assume a certain inclination to implement the J-laying type of the pipeline .

In the J-laying type , the span of the pipeline 2 assumes a J shape , due to the single curvature of said span, and extends mainly in the vertical direction . J- laying uses a substantially vertical laying line 6 , included within the laying tower 5 .

According to a variant not shown, the laying tower 5 is mounted on the bow . According to another variant not shown, the laying tower 5 is mounted on a balcony along one of the sides of the floating structure 4 .

The laying tower 5 has an upper portion 14 equipped with devices (not shown) to assemble pipe segments (not shown) in order to reali ze the pipeline 2 as the pipeline 2 is laid; a central portion 15 equipped with a clamping assembly 16 configured to clamp and advance the pipeline 2 during assembly; and a lower portion 17 comprising a laying ramp 18 .

The clamping assembly 16 comprises a clamping unit 19 fixed to the laying tower 5 and a clamping unit 20 , which is arranged in series with respect to the clamping unit 19 and is mobile along the laying line 6 between a first position, at a first distance from the clamping unit 19 , and a second position, at a second distance from the clamping unit 19 , wherein the first distance is greater than the second distance .

In other words , the clamping unit 20 is mobile parallel to the laying line 6 so that by alternately gripping the two clamping units 19 and 20 it is pos sible to advance the pipeline 2 along the laying tower 5.

Furthermore , the floating structure 4 comprises two parallel arms 21 ( only one of which is shown in Figure 1 ) that extend above the open deck 12 and support the laying tower 5 in a rotatable manner . In this way, the rotation axis Al of the laying tower 5 is arranged above the open deck 12 at the ends of the arms 21 .

In the case described and shown herein, the manipulator device 7 is arranged on the open deck 12 at the laying tower 5 , is mobile with respect to the laying tower 5 , and is configured to apply the modules 8 around the pipeline 2 section comprised between the clamping units 19 and 20 .

With reference to Figures 3- 6 , the manipulator device 7 comprises two j aws 22 , which are mobile between an open and a closed position and are configured to house respective portions 9 of module 8 ; and an articulated mechanism 23 , which has a plurality of degrees of freedom and is configured to place the aws 22 in a loading position and in a position wherein they are aligned with the pipeline 2 during assembly .

The mechanism 23 comprises a base body 25 , which is fixed to the open deck 12 ; an arm 26 , which is hinged to the base body 25 around a rotation axis A2 ; two actuators 27 , which are configured to actuate the rotation of the arm 26 around the rotation axis A2 ; and a slide 28 , which is coupled to the arm 26 and the j aws 22 and is configured to selectively move the j aws 22 with respect to the arm 26 in a direction DI . The mechanism 23 further comprises an elongated body 29 , which extends along a longitudinal axis A3 , is coupled to the slide 28 and supports the two j aws 22 in a mobile manner ; and an actuator 30 , which is coupled to the slide 28 and the elongated body 29 and is configured to actuate the movement of the aws 22 in the direction DI .

In particular, the j aws 22 extend on opposite sides with respect to the elongated body 29 and are coupled to the elongated body 29 in a mobile manner between an open and a closed position .

Each j aw 22 comprises a frame 31 , which is hinged to the elongated body 29 around a rotation axis substantially parallel to the longitudinal axis A3 , and respective gripping belts 32 , which are supported by the frame 31 and are configured to accommodate and selectively hold respective portions 9 of module 8 .

The frame 31 comprises an elongated body 33 , which extends along a respective longitudinal axis A4 substantially parallel to the longitudinal axis A3 ; two transverse elements 34 , which are fixed to the elongated body 33 at a distance from each other and are configured to accommodate respective portions 9 of module 8 ; and a side bar 35 , which is fixed to the ends of the transverse elements 34 so as to delimit together with the transverse elements 34 a housing seat 36 for the portion 9 of module Although in the case described and shown herein, which is not limiting to the present invention, each of the housing seats 36 is configured to accommodate two portions 9 of module 8 arranged in series , each j aw 22 may be configured to accommodate a di f ferent number of portions 9 of module 8 in the respective housing seat 36 . In particular, in accordance with a variation of the embodiment described and shown, each housing seat 36 may be configured to accommodate four portions 9 of module 8 .

Each aw 22 is equipped with four belts 32 arranged at a distance from each other along the longitudinal axis A4 , and with clamping devices 37 ( Figure 6 ) , each of which is actuated by respective actuators 38 ( Figure 5 ) and is configured to clamp the respective belt 32 around the portion 9 of module 8 .

Each belt 32 is shaped to accommodate and hold a portion 9 of module 8 and in this case it extends along a given arc of circumference .

Each j aw 22 further comprises at least one preloading cylinder 39 ( Figure 3 ) , which is coupled to the respective elongated body 33 and is configured to push the respective portion 9 of module 8 against the pipeline 2 section when the j aws 22 are in closed position around the pipeline 2 section; and at least one automatic screwdriver 40 ( Figures 4 and 5 ) , which is carried by the respective transverse element 34 and is configured to screw together two respective portions 9 of module 8 with a set tightening torque .

With reference to Figure 6 , the mechanism 23 comprises an adj usting device 41 , which is configured to adj ust the inclination of the j aws 22 around a rotation axis A5 substantially parallel to the second rotation axis A2 when the j aws 22 are in proximity to the said pipeline 2 section .

In particular, the adj usting device 41 comprises an actuator 42 , preferably a hydraulic cylinder, which acts on the elongated body 29 , causing the elongated body 29 and the j aws 22 supported by the elongated body 29 to rotate around the rotation axis A5 .

In addition, the mechanism 23 comprises two contact sensors 43 fixed to opposite ends of the elongated body 29 . Each contact sensor 43 is configured to emit a contact signal when in contact with the pipeline 2 , providing the adj usting device 41 with a feedback to actuate the actuator 42 to precisely align the j aws 22 to the pipeline 2 .

With reference to Figure 7 , a particular embodiment of the present invention is shown, wherein the laying vessel 1 comprises a crane 44 arranged on the open deck 12 and configured to li ft the portions 9 of module 8 from the open deck 12 so as to place them on the manipulator device

7 .

The crane 44 is equipped with an adj ustable gripping tool 45 configured to li ft a li fting frame 46 , which supports each portion 9 of module 8 .

In particular, the adj ustable gripping tool 45 is configured to adj ust the position and/or the inclination of each portion 9 of module 8 with respect to the manipulator device 1 so as to precisely insert each portion 9 of module

8 into the respective j aw 22 .

In use and with reference to Figure 7 , the manipulator device 7 is in the loading position on the open deck 12 . In such a configuration, the arm 26 is folded over the base body 25 , the j aws 22 are in an open position facing upwards , and the portions 9 of module 8 are loaded into the respective housing seats 36 of the j aws 22 .

The crane 44 picks up the portions 9 of module 8 from the open deck 12 and places them at the j aws 22 of the manipulator device 7 . In such circumstances , the li fting frame 46 is supported at the adj ustable gripping tool 45 and in turn supports the portions 9 of module 8 . When the portions 9 of module 8 are in proximity to the manipulator device 7 , the adj ustable gripping tool 45 adj usts the position and the inclination of each portion 9 of module 8 with respect to the manipulator device 1 so as to precisely place each portion 9 of module 8 in the respective jaw 22.

Subsequently, the belts 32 are clamped around the respective portions 9 of module 8 by means of the clamping devices 37 (Figure 6) .

With reference to Figure 8, the arm 26 is lifted by means of the actuator 27 to bring the aws 22 into a vertical position at the pipeline 2 section to which the module 8 is to be applied. The arm 26 is inclined with respect to the open deck 12 so as to align the jaws 22 with the laying line 6, which, in the case described and shown, is substantially vertical.

In accordance with variants of the present invention, not shown in the appended Figures, the laying tower 5, and consequently the laying line 6 may assume different inclinations with respect to the open deck 12. In such configurations, the inclination of the arm 26 is adapted to the inclination of the laying line 6 so as to align the jaws 22 with the pipeline 2 during assembly.

With reference to Figure 9, the slide 28 (Figures 4- 6) moves the jaws 22 in the direction DI along the laying line 6 so as to precisely adjust the longitudinal position of the jaws 22 with respect to the pipeline 2 section to which the modules 8 are to be applied.

The adjusting device 41 actuates the actuator 42 to adjust the inclination of the jaws 22 around the rotation axis A5 so as to follow the oscillations of the floating structure 4 and of the laying tower 5 .

With reference to Figure 10 , the j aws 22 are closed around the pipeline 2 section during assembly . Subsequently, the preloading cylinders 39 ( Figure 4 ) push the respective portion 9 of module 8 against the pipeline 2 section and the screwdrivers 40 ( Figures 5 and 6 ) screw together two respective portions 9 to assemble the module 8 with a set tightening torque . At this point , the preloading cylinders 39 ( Figure 4 ) release the thrust on the portions 9 and the belts 32 are opened so as to decouple the aws 22 from the modules 8 to separate the manipulator device 7 from the pipeline 2 .

With reference to Figure 1 , once the module 8 has been applied, the clamping unit 19 releases the grip from the pipeline 2 and the clamping unit 20 is moved from the first position to the second position along the laying line 6 to advance the pipeline 2 and lay the pipeline 2 section to which the module 8 has been applied .

In accordance with an embodiment , all the steps of applying the modules 8 to the pipeline 2 and of laying the pipeline 2 described above are carried out in an automated manner without the need for the direct intervention of operators .

Finally, it is evident that variations with respect to the embodiment described can be made to the present invention without however departing from the scope of the following claims .