WITHOUT TP-E FLOATS, FOR THE TRANSPORT OF FLUIDS UNDER PRESSURE CONTAINING MATERIALS, ALSO ABRASIVE ONES

[0001] The present finding has as its object a thermoplastic pipe with inner coextruded TP-E layer, with or without TP-E floats, for the transport of fluids under pressure containing materials, also abrasive ones.

Field of application

[0002] The innovation finds its specific, even though not exclusive, application in the field of production industry of pipes and tubes for the transport of solid, fluid, liquid or gaseous substances and particularly in the field of the production and commercialization industry of pipes used for the dredging and the drainage and, widely, in the industry of the production and commercialization of pipes used for the transport of hydrocarbons, in particular oil.

[0003] At the moment, all those systems used for the transport of fluid materials are well-known, systems that take the form of pipes or tubes which are transport systems that synthetically implement a hollow solid with constant areal section, and that are characterized by the absence of dispersion of the transported material outward, whether solid, even with different granulometry, fluid, liquid or gaseous. With reference to the field of application of pipes for the transport of materials, in particular fluid materials, those systems implemented for the transport of the material dredged by means of well-known dredging equipment, or for the transport of hydrocarbons, in particular in a crude state such as oil, result of particular interest for the invention. Briefly and without claiming exhaustiveness, the types of dredging are all aimed, at least, at obtaining the lowering and the maintenance of the bottom of rivers, seas, oceans, lakes, mines, necessary for the transit of ships and boats, or the beach nourishment, the transport of mining materials, the lowering of the bottom of a water basin or even the removal of polluted or differently contaminated material. Given the main purposes of the dredging operations, it is possible to distinguish, as a first approximation, infrastructural dredging, maintenance dredging and reconditioning or reclamation dredging. In the current technical panorama, the procedures and the correlative equipment to perform underwater bottoms dredging are well known. Briefly, the dredging procedure consists in underwater excavation operations usually performed by using appropriate dredgers that are chosen on the basis of the characteristics of the material to be excavated and, extensively, with reference to the characteristics of the dredging site. T raditionally, the dredging equipment consists in equipment capable of carrying out excavation operations and equipment capable of transporting the dredged material towards defined storage sites. As a first approximation, dredgers can be distinguished into mechanical type and hydraulic type dredgers, on the basis of the fact that, for mechanical type dredgers the removal of the material is performed by using technologies similar to the ones used in excavations on land, while for hydraulic type dredgers by using instead centrifugal pumps in which the dredged material is removed as a result of the depression generated by the pump in the pick-up area, keeping into consideration that can be extensively defined hydraulic dredgers also those in which the operation is performed by means of a mechanical excavation system and of a dredged material hydraulic conveying system. For purely indicative purposes, among the mechanical type dredgers, it is possible to distinguish bucket ladder dredgers in which a self-propelled conveying belt is equipped with a number of appropriate containers aimed to the collection of the material, being the collection performed consequently to the impressed movement of the above mentioned belt, that is partially immerged; backhoe dredgers, which are equipped with a backhoe excavator; grab dredgers, which are equipped with an articulated mechanical arm provided with a biting bucket. Among the hydraulic dredgers, suction dredgers are currently known, equipped with a suction pump for the suction of the material to be dredged; cutter suction dredgers, which are additionally equipped with a head equipped with a rotary cutter; trailing suction hopper dredgers which are equipped with a suction head, that is made to crawl on the seabed to be dredged and that, by means of appropriate pipelines, feeds the dredged material into the hold, and which discharge the dredged material from the hold to the ground by means of pipelines. As a consequence of removal operations of dredging material performed by the dredgers, several solutions have been developed to allow its transport for discharge purposes, where the above-mentioned solutions are strictly dependent on the type of dredger used and on the peculiarity of the site where the dredging operations take place and the transport operations have to be carried out. In this way, in order to conveniently transport the removed dredging material, it is usual to expect the use of pipelines, consisting in contiguously joined pipes, being generally equipped with connecting flanges, and being conveniently made of material with the specificity of being resistant to abrasion. In the current state of technology, pipelines are known to be made of metal material, usually steel, as well as of synthetic material such as resins or plastics with specific characteristics of abrasion resistance such as, currently and widely, Polyethylene. The requirements for dredging material transport include the necessity of implementing floating pipelines, also and not exclusively placed in order to allow the dredger to make the necessary movements along the dredging area, or more widely, in order to allow the immediate identification of the pipeline. Pipelines are also largely employed as conveying systems, largely used in the extraction industry, particularly the oil extracting one, in order to conveniently transport the oil that is extracted from the reservoir at least to a storage site. In the current state of technology, oil transport dedicated pipelines are usually implemented by means of the appropriate junction of a number of pipes, preferably made of steel.

[0004] In order to achieve the buoyancy of a pipeline, the currently known state of the art of some solutions defines that each pipe, particularly dredging pipe, can be equipped with removable floating devices, which are opportunely connected and placed on the pipe itself, thus requiring the preparation and the assembly of separate devices, the dredging pipe and the floating device respectively. In addition, the current state of the art assumes that the pipe, particularly the dredging pipe, is made floating by connecting a floating device so that its entire longitudinal extension is almost entirely enveloped, leaving the areas corresponding to the ends uncovered, making it possible for the workers to perform the necessary joining operations of one pipe to another, or by connecting appropriate floating devices to the pipe that has to be made floating, placing them along the longitudinal extension of the pipeline, being these floating devices implemented as reciprocally associable half-shells. For some of the solutions referred to in the current know state of the art, the buoyancy of each pipe is basically achieved by the subsequent assembly of floating devices, requiring in this way the involvement of specialized personnel for the positioning of the floating devices, being necessarily separate also their management and storage. With particular reference to pipes implementing pipelines for dredging, pipelines implemented in the guise of a tube are known, tube that, if made of metal material, is equipped with flanges provided along their perimeter with through-holes for the engagement, in order to allow the reciprocal junction of two or more pipes. Having been observed, among other things, that metal dredging pipes are more subject to wear and, due to the connatural stiffness of the material, more difficult to manoeuvre, some companies in the sector have decided to adopt solutions for dredging pipes made of synthetic material such as, for example, plastic resins and in particular polyethylene. With reference to pipes made of synthetic material, they are usually expected to be structured in a way that, at each end, they have a part of stub-end joint or electro-weldable sleeve co-operating with a designated flange provided along its perimeter with engage through-holes for threaded engaging devices.

[0005] Some solutions for dredging pipes and/or related floats are also reported in current patent literature. Among the reported solutions, for example, the following are quoted

D1 : n. US5722794 (Friederich et al.)

D2: n. US20011/0053444 (Benedetti)

D3 n. ITTV2011A000053 (Kiasma)

D4 n. ITTV20140036 (Kiasma)

[0006] D1 briefly describes a float for flexible pipes, which is equipped with a multi-layer body made of expanded material enclosing the same pipe in order to make it buoyant, being moreover equipped with a textile winding that encloses the floating element, made of expanded material, enclosing the same flexible pipe. In particular, the above-mentioned textile winding is expected to be placed in a way as to form several transversal layers and, moreover, an external coating made of an elastomer, a thermoplastic elastomer or a thermoplastic material, is expected. The float is supposed to be further provided with a transverse reinforcement made of textile material which is arranged in such a way to create, in relation to its axis, an angle between 75° and 90°, and preferably between 85° and 90°.

[0007] D2 briefly describes a floating device for pipes including at least two removably associable floating elements, each of them including a semi-tubular body, creating a housing for a pipe, where the substantially semi-tubular body of the floating elements has at least one first protrusion and at least one first notch at a second longitudinal edge of it, and at least second protrusion and at least a second notch at one first opposed longitudinal edge, and, favourably, the protrusions are substantially aligned with the notches from opposite parts with respect to the longitudinal centreline plane of the floating element, in order to allow at least a partial interpenetration of the substantially semi tubular bodies of the floating elements.

[0008] D3 briefly describes a solution consisting in a floating dredging pipe including a dredging pipe equipped with engaging flanges provided with through-holes being the dredging pipe steadily equipped, at the area in between its ends, with at least one floating device made of closed-cell type, rigid expanded polyurethane resin, being the floating device steadily anchored to the pipe by means of a coating made of synthetic material, in particular polyethylene, which appropriately engages both the pipe and the floating device.

[0009] D4 briefly describes a solution consisting in a floating dredging pipe for the transport of fluids under-pressure equipped with devices for the enhancement of the buoyancy efficiency and with means for the efficiency enhancement of the flow motion of the transported material, solution that includes a pipe equipped at least with one single-piece floating device, removable and anchored to the pipe by means of electro-welded metal collars placed at the ends of the same pipe, being the said pipe equipped with at least one device to enhance the efficiency of the flow motion inclusive of some shaped fins radially arranged and placed, internally, at least at one end of the pipe, being the above-mentioned shaped fins capable of inducing a change in the internal flow’s motion of the fluid under-pressure that passes through the pipe, causing a transformation in the motion of the said flow, from linear to turbulent.

Drawbacks

[0010] All the solutions consisting in pipes for the dredging sector and the transport of fluids under-pressure, as well as of floating devices for pipes for the dredging sector and the transport of fluids under-pressure, solutions referred to in the known state of the art, show defects and limitations that can be traduced in consequent disadvantages.

[0011] In the applicant’s opinion, a first drawback characterizing all the solutions consisting in pipes for fluids under-pressure and floating devices for pipes for fluids under-pressure, solutions referred to in the known state of the art, has been detected in the recognized fact that all the above-mentioned known solutions, consisting in pipes for the transport of fluids under-pressure, due to the current material used for their implementation, do not guarantee an optimal resistance to abrasion and an adequate reduction of the pressure loss.

[0012] In the applicant’s opinion, a second drawback characterizing all the solutions consisting in pipes for fluids under-pressure and floating devices for pipes for fluids under-pressure, solutions referred to in the known state of the art, has been detected in the recognized fact that all the above-mentioned known solutions consisting in pipes for the transport of fluids under-pressure do not guarantee an adequate resistance to impacts caused, in particular, by the passage of the dredged material, as well as they do not guarantee an adequate resilience to impact or an adequate resistance to the laceration caused by the passage of material containing pointed solids and/or relatively large solids.

[0013] In the applicant’s opinion, a third drawback characterizing all the solutions consisting in pipes for fluids under-pressure and floating devices for pipes for fluids under-pressure, solutions referred to in the known state of the art, has been detected in the recognized fact that all the above-mentioned known solutions consisting in pipes for the transport of fluids under-pressure do not guarantee an high degree of flexibility and bendability combined to an adequate yield resistance and elongation at break.

[0014] In the applicant’s opinion, another drawback characterizing all the solutions consisting in pipes for fluids under-pressure and floating devices for pipes for fluids under-pressure, solutions referred to in the known state of the art, has been detected in the recognized fact that all the above-mentioned known solutions consisting in pipes for the transport of fluids under-pressure do not guarantee an optimal resistance to impacts and an optimal buoyancy, moreover the current solutions consisting of floating devices for pipes for the transport of fluids do not result optimized regarding the materials used for their implementation, being implemented in such a way that they include a coated polyurethane filling, with a consequent reduction in their overall buoyant performances.

[0015] In the applicant’s opinion, a further drawback characterizing all the solutions consisting in pipes for fluids under-pressure and floating devices for pipes for fluids under-pressure, solutions referred to in the known state of the art, has been detected in the recognized fact that all the above-mentioned known solutions consisting in pipes for the transport of fluids under-pressure are not implemented in such a way that they can be easily recycled once their useful life is over.

[0016] Overall, on the basis of these introductory considerations, it is clear that the identification of alternative solutions is certainly preeminent.

[0017] The purpose of the present finding is also to solve these above- mentioned drawbacks.

Summary of the finding

[0018] This and other purposes are achieved with the present innovation, according of the characteristics set out in the attached claims, solving the presented problems by means of a thermoplastic pipe with inner coextruded TP-E layer, with or without TP-E floats, for the transport of fluid under-pressure containing materials, also abrasive ones, which includes a pipe body (2) implemented in synthetic material and where the said pipe (1) is suitable to be part of a pipeline (1) where the pipe body (2) includes at least an outer wall (21) made of thermoplastic material and at least an inner wall (22), coaxial with the outer wall (21), made of thermoplastic-elastomeric material.

Purposes and advantages

[0019] In such way, by means of the remarkable creative input, whose effect determinates an immediate technical progress, multiple advantages are achieved.

[0020] One first advantageous purpose of the proposed solution is the fact to allow, by means of the implementation of a thermoplastic pipe with inner coextruded TP-E layer with or without TP-E floats for the transport of fluids under-pressure containing materials, also abrasive ones, the implementation of a pipe for the transport of fluids under-pressure which, thanks to its particular structure, allows an optimal resistance to abrasion and an adequate reduction of the pressure loss.

[0021] A second advantageous purpose of the proposed solution is the fact to allow, by means of the implementation of a thermoplastic pipe with inner coextruded TP-E layer with or without TP-E floats for the transport of fluids under-pressure containing materials, also abrasive ones, the implementation of a pipe for the transport of fluids under-pressure which, thanks to its particular structure, allows an optimal resistance to impacts generated in particular by dredging material, moreover allowing to guarantee an adequate impact resilience and an adequate resistance to laceration generated by the passage of material containing pointed solids and/or relatively large solids.

[0022] Another advantageous purpose of the proposed solution is the fact to allow, by means of the implementation of a thermoplastic pipe with inner coextruded TP-E layer with or without TP-E floats for the transport of fluids under-pressure containing materials, also abrasive ones, the implementation of a pipe for the transport of fluids under-pressure which, thanks to its particular structure, allows to guarantee an high degree of flexibility and bendability combined to an adequate yield resistance and elongation at break.

[0023] A further advantageous purpose of the proposed solution is the fact to allow, by means of the implementation of a thermoplastic pipe with inner coextruded TP-E layer with or without TP-E floats for the transport of fluids under-pressure containing materials, also abrasive ones, the implementation of a pipe for the transport of fluids under-pressure which, thanks to its particular structure, allows to guarantee a high extension of the useful operating life of the pipe with consequent positive impacts in terms of total operating cost control.

[0024] Another advantageous purpose of the proposed solution is the fact to allow, by means of the implementation of a thermoplastic pipe with inner coextruded TP-E layer with or without TP-E floats for the transport of fluids under-pressure containing materials, also abrasive ones, the implementation of floating devices for pipes for the transport of fluids under-pressure, such as they guarantee an optimal resistance to impacts and an optimal buoyancy, moreover resulting optimized in terms of the materials used for their implementation, being implemented in such a way that filling materials are not required, thus increasing their overall performances of buoyancy.

[0025] A further advantageous purpose of the proposed solution is the fact to allow, by means of the implementation of a thermoplastic pipe with inner coextruded TP-E layer with or without TP-E floats for the transport of fluids under-pressure containing materials, also abrasive ones, the implementation of a pipe and a floating device for pipes for the transport of under-pressure fluids both implemented in such a way to be easily recycled once their useful life is over.

[0026] These and other advantages will emerge from the following detailed description of some preferential implementing solutions with the support of the attached schematic drawings whose implementing details do not have to be considered restrictive but just illustrative.

Content of the drawings

Picture 1 shows an overall axonometric view of a thermoplastic pipe with inner coextruded TP-E layer with or without TP-E floats, for the transport of fluids under-pressure containing materials, also abrasive ones, referred to in the finding of the present invention.

Picture 2 shows a cross-sectional view of the pipe, object of the present invention, referred to in Picture 1;

Picture 3 shows a longitudinal sectional view of the pipe, object of the present invention, referred to in Picture 1;

Picture 4 shows a cross-sectional view of the pipe, object of the present invention, equipped with fitting for flanging and flange;

Picture 5 shows a longitudinal sectional view of the pipe, object of the present invention, equipped with fitting for flanging and flange;

Picture 6 shows a view of two pipes, referred to in the finding object of the present invention, joined by flanging;

Picture 7 shows a frontal view of the floating device, referred to in the finding object of the present invention, implemented in two half-shells;

Picture 8 shows a top plan view of the floating device, referred to in Picture 7, connected to the pipe;

Picture 9 shows an axonometric view of two half-shells constituting the floating device, referred to in Picture 7, in association with the pipe;

Picture 10 shows a pipe with associated floating devices, referred to in the finding object of the present innovation;

Picture 11 shows a top plan view of a floating device, referred to in Picture 10, engaged to the pipe; Picture 12 shows a frontal view of the floating device, referred to in Picture 11 ;

Picture 13 shows a sectional view of the floating device, referred to in Picture 11 ;

Picture 14 shows a sectional view of the floating device, referred to in Picture 12;

Picture 15 shows an overall axonometric view of a floating device referred to in the finding object of the present innovation;

Picture 16 shows a top plan view of the floating device, referred to in Picture 15, engaged to a pipe;

Picture 17 shows a sectional view of the floating device, referred to in Picture 16.

Practical implementation of the finding

[0027] With reference also to the representations contained in Pictures from 1 to 17, a thermoplastic pipe with inner coextruded TP-E layer is described, with or without floats, for the transport of fluids under-pressure containing materials, also abrasive ones, pipe that, as particularly described in the overall representation reported in Picture 1 illustrating a possible example of the finding’s implementation, to be considered as a base implementing solution with reference to the pipe (1) object of the finding, is expected to be particularly suitable to respond to the needs especially for dredging, or that can also be suitable to respond to the needs connected to the transport of petroleum products, such as conventionally crude oil, being the above-mentioned pipe (1) suitable for the conventional transport at least of solid, fluid or liquid material. The above-mentioned pipe (1) is expected to include a pipe body (2) which, in the described example of implementation, is implemented with appropriate synthetic material, material that, as specified in the continuation of the description, is such to be compliant, at least, with specific abrasion resistance and resilience characteristics.

[0028] It is required that the expected pipe body (2), referred to in the finding, has to be implemented in such a way to result suitable to form an element of pipelines that are expected to be implemented, particularly even though not exclusively, for dredging purposes, being in this case the length and the diameter of the pipe body (2) appropriate to the scope of application, usually expecting the length of the pipe body (2) to be preferably ranging between 6 and 13,5 meters long, while the diameter of the pipe body (2) to be preferably ranging between 160 and 1200 millimetres. It is further expected, especially in the case of pipes (1) for dredging pipelines, that the pipe body (2), referred to in the pipe (1) object of the finding, is implemented in such a way to operate with pressure values at least ranging between 4 and 20 bar. In any case, it is required that the values of length, diameter and thickness of the pipe body (2), as well as the operating pressure values, result compliant with the specific and contingent needs of the destination of use, particularly given by the real scope of use of the pipe (1). Being the implementation of a pipeline (1) the destination of use of the pipe (1), it is expected that every pipe (1) constituting the pipeline (1) can be conveniently joined to the contiguous one by flanging or by welding, being the latter implemented, in particular, by electrofusion. More in detail, it is expected that the pipe (1), is equipped, in a known way, with junctions made of terminal sleeves/collars welded by electrofusion to the outer surface of the pipe (1), as well as, in a known way for joining purposes, with steel flanges (4), gaskets, bolts and nuts. In particular, in the case that the junction between one pipe (1) and the contiguous one is performed by welding implemented by electrofusion, it is expected that the pipe body (2) is provided with known connectors consisting in sleeves and/or electrofusion collars, which incorporate an electric heating spiral that melts the thermoplastic material constituting both the connector and the pipe body (2) in the joining area, causing the junction by fusion. More in detail of the described implementing example it is expected that, conventionally in the case of joining by flanging, the pipe body (2) includes at both two ends a protruding edge (3) for anchoring and stopping the flange (4), being this last of known type, provided with a number of through-holes (41) placed in order to allow the junction between two implemented pipes (1), where the junction by flanging is performed by using usual threaded fasteners, conventionally steel bolts aimed at engaging the flanges (4) of two contiguous pipes (1). In order to perform a sealed junction, the placement of an adequate gasket of known type in between the flange (4) of a pipe (1) and the flange (4) of the contiguous pipe (1) is expected. In detail, each protruding edge (3) is expected to be coupled at the terminal end of the pipe body (2) by a conventionally known procedure, usually thermo-welding, being the above- mentioned thermo-welding performed in such a way that no steps are created inside the pipe (1), in order to avoid the arise of unusual abrasion of the inner surface of the pipe body (2) when the material to be transported is made passing through it.

[0029] More in detail, it is expected that the pipe body (2) of the pipe (1), object of the present invention, is implemented in such a way to include at least an outer wall (21) made of thermoplastic material, particularly Polyethylene, preferably high density HDPE type, expecting that the material used for the implementation of the above-mentioned outer wall (21) can also be medium or low density polyethylene, type: MDPE, LDPE or LLDPE. On the basis of the specific destination of use of the pipe (1) it is expected that the above-said outer wall (21) of the pipe body (2) can be implemented with high density polyethylene (HDPE) when the particular implementation of the pipe body (2) needs characteristics of higher stiffness and resistance, particularly tensile strength, as well as an higher resistance to the exposition at relatively high temperatures in comparison to other polyethylene compounds with lower density. In the event instead in which the outer wall (21) of the pipe body (2) has to be implemented with characteristics such that no particularly high stiffness and tensile strength are required, while a high resilience is necessary, for the implementation of the outer wall (21) of the pipe body (2) it is preferable, as implementing material, the use of medium or low density polyethylene (MDPE, LDPE). With reference instead to the mechanical characteristics of the low-density polyethylene (LDPE), in case that the resistance to laceration, the resistance to impact and the resistance to puncture result to be preeminent, for the implementation of the outer wall (21) of the pipe body (2) as manufacturing material of the outer wall (21) of the pipe body (2), it is preferable the use of linear low density polyethylene (LLDPE). In the described implementing example and preferably, in the hypothesis of implementing a pipe (1) for the dredging sector, it is expected that the material constituting the outer wall (21) of the pipe body (2) is the high density polyethylene HDPE 100. It is widely expected that the outer wall (21) of the pipe body (2) can be also implemented as a double-layer or multi-layer type, expecting in any case the manufacturing materials of the outer wall (21) to be thermoplastic, preferably polyethylene polymers of the HDPE, MDPE, LDPE, LLDPE type.

[0030] In order to lend specific characteristics of high abrasion resistance and resilience to the pipe (1) referred to in the finding, the pipe body (2) is expected to be implemented in such a way to include at least an inner wall (22), coaxial with the outer wall (21), inner wall (22) that is expected to be implemented in thermoplastic-elastomeric material, conventionally TP-E, of the type typically constituted by a polymeric mixture composed in a known way by plastic material and rubbery material, so that it is possible to combine in one single material both thermoplastic and elastomeric properties, thus resulting combined in one single material the advantages given by the two components. In particular, it has been considered in an innovative way the use of a thermoplastic- elastomeric material, TP-E, for the implementation of the inner wall (22) of the pipe body (2) in order to lend characteristics of high bending resistance, high tear and abrasion resistance, high impact resistance, low specific weight, high chemical resistance, high weather resistance and high resistance to thermal excursion to the latter, being further advantageous according to the possibility of being coloured and recycled. More in detail, the fact of implementing the inner wall (22) of the pipe body (2) in thermoplastic-elastomeric material, TP-E, results particularly advantageous in the field of pipes (1) for the dredging sector, and in general for the transport of fluids under-pressure containing mixtures of transported solids, in particular due to the fact of being characterized by a high resistance to wear due to abrasion and high resilience in comparison to analogue pipes (1) of a known type, implemented in steel or thermoplastic HDPE. Carried-out laboratory tests have proved that, with reference to a comparison among parameters of resistance to wear due to abrasion, the inner wall (22) of the pipe body (2), referred to in the finding, is comparable to the resistance to wear due to abrasion of a pipe (1) implemented in X-70 inox steel type, moreover the fact of having provided the pipe body (2) with an inner wall (22) implemented in TP-E, in the comparison with analogue pipes made of thermoplastic HDPE, allows to exhibit that the useful life can result even double in the case of use for the transport of mixtures with non-burdensome solids. In comparison with pipes (1) made of thermoplastic HDPE, currently known in the dredging field, the fact of having expected the inner wall (22) to be implemented in thermoplastic-elastomeric TP-E, makes it possible to use pipes (1) made of synthetic material also for the transport of fluids under-pressure containing mixtures with burdensome solids.

[0031] With reference to the characteristics of resilience typical of the pipe (1), referred to in the finding, carried out comparative technical tests have proved that, the fact of having implemented, in an innovative way, the inner wall (22) of the pipe body (2) in thermoplastic-elastomeric TP-E, allows to achieve a much higher resilience than the one that could be achieved by an analogue pipe (1) made of steel, commonly used in the sector, or of thermoplastic HDPE. In addition, the fact of having implemented the pipe (1), referred to in the finding, in an innovative way with an outer wall (21) made of thermoplastic, preferably HDPE, and of an inner wall (22) made of thermoplastic-elastomeric TP-E, has allowed to combine in one single solution the characteristics of high tear resistance given by the outer wall (21) made of thermoplastic, for example HDPE, together with the characteristics of high resilience given by the inner wall (22) made of composite thermoplastic-elastomeric TP-E. It is widely expected that the inner wall (22) of the pipe body (2) can be also of the type implemented in double layer or multi-layer. As far as the manufacturing process is specifically concerned, it is expected that the pipe body (2) of the pipe (1), referred to in the invention, is implemented through a known co-extrusion process of the outer wall (21) and of the inner wall (22). In the implementation of the pipe (1), referred to in the invention, it’s taken advantage of the fact that the thermoplastic-elastomeric composite, TP-E, used for the implementation of the inner wall (22) of the pipe body (2) can be co-extruded on the thermoplastic material used for the implementation of the outer wall (21) of the pipe body (2), for example HDPE, achieving in this way at least the advantages given by the fact that no vulcanization is needed, by the wide possibility of modulating the level of stiffness and flexibility of the used materials as well as by possibility of using extrusion and co-extrusion devices of known type. In the co-extrusion process involving the pipe (1), referred to in the invention, it is expected that the TP-E composite is first mixed by means of a centrifugal mixer, dehumidified, and then made flowing to an inlet of the co-extruder, where the melting temperature of the TP-E compound is expected to range between 180° and 220°C, thus resulting in the same range of melting values of the thermoplastic HDPE.

[0032] More in detail of the solution, object of the invention, it is expected that, the inner wall (22) of the pipe body (2) is preferably made of a mixture including a percentage of TPE and/or TPU and/or TPO mixed together with a percentage of HDPE and/or MDPE and/or LDPE and/or LLDPE. Even more in detail, a carried-out test has allowed to define that, for the purpose of the transport of fluids under-pressure consisting of mixtures containing not particularly burdensome solids, the inner wall (22) of the pipe body (2) that is co-extruded to the outer wall (22) has to be preferably composed of a mixture with the addition of a matrix of thermoplastic elastomer belonging to the family of TPE and/or TPU and/or TPO in a percentage that ranges between a 40% of HDPE and/or MDPE and/or LDPE and/or LLDPE and a 60% of a thermoplastic of the family of TPE and/or TPU and/or TPO. In case that the fluids under-pressure that have to be transported are composed instead by a mixture containing very burdensome solids, carried-out tests allow to define that the inner wall (22) of the pipe body (2) that is co-extruded to the outer wall (21) has to be preferably composed of a mixture with the addition of a matrix of thermoplastic elastomer belonging to the family of TPE and/or TPU and/or TPO with a percentage of about 70% with the addition of a HDPE and/or MDPE and/or LDPE and/or LLDPE thermoplastic mixture with a percentage of about 30%. In addition, it is expected that the thickness of both the outer wall (21) and the inner wall (22) of the pipe body (2) is determined on the basis of the contingent requirements of the project.

[0033] Even if the material constituting the pipe (1), referred to in the finding, is appropriate to lend a certain degree of buoyancy to the pipe (1), as notoriously happens in particular for pipes (1) used for dredging operations, in order to lend a buoyant capacity to the pipe (1) such as, at least the weight of the fluid under- pressure passing through is balanced, it is expected that the pipe (1) is provided at least with an adequate floating device (5). The above-mentioned floating device (5) that equips the pipe (1), long at least as a part of its length, allows the pipe (1) to surface on water under operating conditions. Necessarily in order to ensure the optimal buoyancy of the pipe (1), the dimensions of the floating device (5) are such to result proportional and respondent to the size and weight parameters of the pipe (1), as well as proportional to the weight of the transported material that has to flow through the pipe (1), expecting the floating device (5) to be of such size that it does not extend over the whole length of the pipe (1) so that the areas close to the ends of the pipe (1) are kept free. Conventionally, it is expected that more than one floating device can be associated to the pipe (1), where each floating device (5) is spaced from a contiguous one, expecting also in this case that the areas close to the ends of the pipe (1) are kept free. In addition, each floating device (5) is implemented in such a way to include an adequate longitudinal seat (53) for the engagement to the pipe body (2) of the pipe (1).

[0034] More in detail of the example of the implementation that is described, it is expected that each floating device (5) is composed at least of one first half shell (51) and of a second half-shell (52), each of them provided with a longitudinal seat (53) for the engagement to the pipe body (2) of the pipe (1), expecting the above mentioned half shells (51, 52) composing the floating device (5) to be implemented in such a way that they can be properly committed to each other, usually by means of well-known threaded engagement devices, thus resulting anchored to the pipe body (2) of the pipe (1) of which they will constitute the equipment. In an innovative way with regard to the existing solutions of known floating devices (5), being the latter usually implemented in such a way to include a closed-cell polyurethane foam filling on an outer shell usually made of thermoplastic material such as, ad example, MDPE, in the solution, which is the object of the finding, it is expected that the floating device (5) both if it consists in one single piece or if it consists in two half-shells (51 , 52), is implemented in such a way that the constituting material that implements it is exclusively constituted by thermoplastic-elastomeric materials, TP-E. The use of thermoplastic-elastomeric materials, TP-E, for the implementation of the above-mentioned floating devices (5) has been found, according to carried-out technical tests and with regard to the currently known solutions constituting floating devices (5), able to guarantee an higher resistance to impacts given by the characteristic resilience of the material, as well as an higher resistance to the thermal excursion. In this way, the use of a thermoplastic-elastomeric material, TP-E, for the implementation of the floating device (5), makes the use of filling materials, such as polyurethane foams, unnecessary.

[0035] In detail it is expected that the material of constitution of the floating device (5) according to the invention is formed by a mixture with the addition of a thermoplastic elastomer matrix belonging to the TPE and/or TPU and/or TPO family in a percentage varying from 45% to 50% and by a thermoplastic mixture of HDPE and/or MDPE and/or LDPE and/or LLDPE in a percentage varying from 45% to 50%. In a possible variant, the material of constitution of the floating device (5) according to the invention is expected to be a mixture with the addition of a thermoplastic elastomer matrix belonging to the TPE and/or TPU and/or TPO family in a percentage varying from 55% to 60% and a thermoplastic mixture of HDPE and/or MDPE and/or LDPE and/or LLDPE in a percentage varying from 40% to 45%. In addition, the floating devices (5) implemented in accordance with the invention in question are expected to be made using a known rotational moulding process. Legend/key

(1) Pipe

(2) Pipe body

(21) Outer wall

(22) Inner wall

(3) Protruding edge

(4) Flange

(41) Through-holes

(5) Floating device

(51) First half-shell

(52) Second half-shell

(53) Longitudinal seat