WO2011009178A1

WO2011009178A1 - Coating element and process for coating service ducts

Info

Publication number: WO2011009178A1
Application number: PCT/BR2010/000228
Authority: WO
Inventors: José Roberto BERTONCELLO DANIELETTO
Original assignee: Poly Easy Comercial Ltda.
Priority date: 2009-07-21
Filing date: 2010-07-20
Publication date: 2011-01-27
Also published as: BRPI0902393A2

Abstract

The present invention refers to a coating element (1) of polyolefin capable of covering, protecting and insulating curved or straight service ducts (2). Said coating element (1) has a first female end (4a) arranged to involve externally and tangentially to at least one end portion of a first coating element adjacent to the coating element (1), where the first female end (4a) of the coating element (1) and said end portion of said first adjacent coating element are welded together by electrofusion. Said first adjacent coating element can be curved or straight. In a first preferred embodiment of the invention, the coating element (1) comprises a male end (5). In a second preferred embodiment of the invention, the coating element (1) comprises a second female end (4b). The present invention also refers to a process for coating curved or straight service ducts (2).

Description

Specification of Patent of Invention for "COATING ELEMENT AND PROCESS FOR COATING SERVICE DUCTS".

The present invention refers to a cover for use in the coating of ducts. More particularly, the present invention refers to a coating element made of polyolefin capable of covering, protecting and insulating curved or straight service ducts.

The present invention also refers to a process for coating curved or straight service ducts.

Description of the State of the Art

Service ducts (steel ducts) capable of transporting heated fluids, such as those used in the conduction of heated liquid hydrocarbons, fuel oil or hot water, must be insulated by means of a polyurethane foam (PU) and coated by a cover in the form of a tube made of polyolefinic material, normally polyethylene or polypropylene.

The purpose of said coating is to guarantee mechanical protection for the service duct against tears, punctures, etc. and liquid and humidity seal-tightness so as to avoid chemical and galvanic corrosion thereof.

Currently, the coating process of straight service ducts is widely known and used. In general terms, circular spacers are applied along a duct bar with the aim of maintaining its concentricity in relation to a polyolefin cover that coats the bar externally. Lastly, polyurethane foam in injected into the space existing between the service duct and the outer cover, so as to ensure thermal insulation of the fluid circulating inside the duct.

However, it is often necessary to apply curved sections along the tubing. For curves with long radii and angles up to the order of 5° it is possible to curve the bars of straight service ducts already coated by means of mechanical benders, without damaging the thermal coating and the polyolefin cover.

In contrast, as yet there is no practical and efficient solution for curves with lower radii with angles over 5°, they become the critical path for works with oil ducts and other heated fluids. The few techniques existing today are based on the use of a curved polyethylene part made by thermoplastic welding between ends of segments of straight tubes, so as to join them angularly. In this process, said curved part is cut along its length (longitudinal extension) and then opened so that it is capable of "coating" the steel duct. Finally, the cut parts are joined longitudinally by thermoplastic extrusion welding or by spaghetti and hot air welding.

However, these handmade techniques are rather slow and heavily dependent on the skill of the worker, rarely allowing for more than 20 m per day to be built, since the welding process by thermofusion of tube segments to make a curved cover is very protracted, and also requires heavy and expensive welding equipment for tubes with diameters over 315 mm, common in the application of thermal ducts. Additionally, the operation of longitudinal cutting of the curved cover, installing it on the curved steel tube and the executing of longitudinal welding significantly increases cost and extends the work period. Further, the manual cut is an arduous process and the final result is often low quality and unsuitable, which may cause a sealing failure and ineffective mechanical protection.

Optionally, another known technique consists of using thermocontractile or thermoretractile polyethylene blankets to coat the joints of steel duct bars, both in the implementation of new duct lines and in repair and maintenance procedures. Said blankets are firstly wrapped around the duct to involve it externally for subsequent application of fire by means of a gas torch, so they can retract and involve the duct bars.

However, these blankets present certain drawbacks and disadvantages, such as, for example:

- lack of adherence on the ducts, since they merely contract against the ducts;

- low mechanical resistance capacity;

- incapability of providing suitable sealing (seal-tightness), since they do not adhere to the ducts adequately;

- movement of the ducts resulting from movement of the ground and/or dilation/contraction due to variations in temperature may displace the blankets, and may leave them exposed, impairing the mechanical protection and favoring corrosion;

- there is no effective quality control method for this kind of coating; and

- the need to use fire at the work site is often prohibited or restricted under safety regulations.

Objectives of the Invention

A first objective of the present invention consists in providing a coating element for application on a bar of curved or straight service ducts (steel ducts), capable of guaranteeing seal-tightness (sealing), safety (resistance), thermal insulation and mechanical protection for said duct, and that also presents a constructive arrangement that enables installation /assembly in a simples, practical, efficient and optimized manner, so as to provide a greater production scale.

Further, it is also a second objective of the present invention to provide a cover, capable of protecting and sealing curved or straight service ducts (steel ducts) that provides greater safety and mechanical protection in relation to the thermoretractible blankets.

Additionally, it is also a third objective of the invention to provide a standardized part, suitable and adapted to coat curved or straight service ducts (steel ducts) so as to enable a greater production scale compared with the production scale of the coating means used today.

Further, it is also a fourth objective of the invention to provide a coating element capable of coating an array of service ducts (steel ducts) having varied angles and bending radii, also disposed in different planes.

Further, it is also a fifth objective of the present invention to provide a coating process for curved or straight steel ducts that is capable of providing appropriate sealing, protection and resistance for said steel ducts in a simple, practical, efficient and optimized manner, and that also dispenses with the need to use fire or thermoplastic welding by extrusion or by spaghetti and hot air welding. Finally, it is a sixth objective of the present invention to provide a coating process for curved or straight steel ducts that substitutes the slow, handmade work that is heavily dependent on the skill of the operator, so as to provide greater simplicity, practicality and efficiency, thus allowing a greater production scale compared to the production scale of the coating processes used today.

Brief Description of the Invention

The first, second, third and/or fourth objective(s) of the present invention is(are) achieved by the provision of a coating element, particularly for coating curved or straight service ducts, which comprises a first female end arranged to involve externally and tangentially at least one end portion of a first coating element adjacent to the coating element, wherein said first female end of the coating element and said end portion of said adjacent first coating element are welded together by electrofusion.

The fifth and/or sixth objective(s) of the present invention is(are) achieved by the provision of a coating process for curved or straight service ducts, characterized by comprising the following steps:

i) mount the service duct on an assembly support;

ii) install spacers along the service duct;

iii) coat the service duct with at least one coating element on the spacers, the coating element having at least one first female end;

iv) coat the service duct with at least one first coating element adjacent to the coating element on the spacers, said adjacent first coating element being curved or straight and having an end portion;

v) accommodate said end portion of said adjacent first coating element in the first female end of the coating element;

vi) adjust the angular deflection between said end portion of said adjacent first coating element and the first female end of the coating element;

vii) fix metallic clamps around the first female end of the coating element and/or of said end portion of said first adjacent coating element; and viii) weld by electrofusion the first female end of the coating element and said end portion of said adjacent first coating element. As mentioned above, the processes are based on the same principle of coating the straight bars, but having as external cover parts made of polyolefin, in standard shapes and sizes, that are installed and welded by electrofusion along the steel tube, and that allow the coating of an array of angles and bending radii, including different planes, with the same part size. Brief Description of the Drawings

The present invention will now be described in greater detail based on examples of execution represented in the drawings. The figures show:

Figure 1 - is a perspective view of a first preferred embodiment of a coating element, capable of coating curved or straight service ducts (steel ducts), object of the present invention;

Figure 2 - is a front view of a bar of a curved service duct (steel duct);

Figure 3 - illustrates a straight connection between the coating element, in a first constructive variation of its first preferred embodiment, and in the adjacent coating element;

Figure 4 - illustrates an angled connection (slanted) between the coating element, in the first constructive variation of its first preferred embodiment, and an adjacent coating element;

Figure 5 - illustrates a straight connection between the coating element, in a second constructive variation of its first preferred embodiment, and an adjacent coating element;

Figure 6 - illustrates an angled connection (slanted) between the coating element, in the second constructive variation of its first preferred embodiment, and an adjacent coating element;

Figure 7 - illustrates an assembly support for the bar of the service duct;

Figure 8 - illustrates the assembly support shown in figure 7 and a projection of the service duct mounted thereon;

Figure 9 - illustrates initial step i of a coating process for curved or straight service ducts by means of at least one coating element according to a first or second embodiment of the present invention;

Figure 10 - illustrates steps ii, iii, iv, v, vi of the coating process, the initial step of which is represented by figure 9;

Figure 11 - illustrates step vii of the coating process, the prior steps of which are represented in figures 9 and 10;

Figure 12 - illustrates step viii of the coating process, the prior steps of which are represented in figures 9, 10 and 11 ;

Figure 13 - illustrates step ix of the process, the prior steps of which are represented in figures 9, 10, 11 and 12;

Figure 14 - is a perspective view of a second preferred embodiment of a coating element, capable of coating curved service ducts (steel ducts), object of the present invention;

Figure 15 - is a front view of the coating element illustrated in figure 14;

Figure 16 - illustrates steps x, xi and xii of a coating process for service ducts by means of at least one coating element according to a second embodiment of the present invention;

Figure 17 - illustrates step xiii of the coating process, the prior steps of which are represented in figures 9 and 16;

Figure 18 - illustrates step xiv of the coating process, the prior steps of which are represented in figures 9, 16 and 17; and

Figure 19 - illustrates step xv of the process, the prior steps of which are represented in figures 9, 16, 17 and 18.

Detailed Description of the Drawings

First Preferred Embodiment

Figure 1 illustrates a coating element 1 capable of coating curved or straight service ducts 2 according to a first preferred embodiment of the present invention. The coating element 1 consists of a part similar to a tube (curved or straight) capable of covering, protecting and insulating at least one portion of a curved or straight service duct 2. It must be noted that the term "curved" can be understood as "dome-shaped in relation to the longitudinal axis" of the coating element or of the duct (important remark: to avoid any kind of confusion, the term "longitudinal" relates to an axis parallel to axis x shown in the figures). Therefore, pursuant to figure 1 , the coating element 1 , when curved, has at least one main portion 3 substantially dome shaped (convex). Optionally, the coating element 1 can present a main straight portion 3, as can be seen in figures 3 to 6.

Preferably, the service duct 2, illustrated in figure 2, consists of a part made of tubular steel in cylindrical format with a circular base. Hence, the service ducts 2 are steel tubes capable of allowing the conduction of various types of fluid, gas or liquid, such as, for example, heated fuel oil, liquid water, among others. Normally, these service ducts 2 are supplied in the form of bars of approximately 12 m. Obviously, this length may vary depending on the need.

As far as the material is concerned, the coating element 1 comprises polyolefin, such as polyethylene, polypropylene or polybutene, capable of providing seal-tightness (sealing), safety (resistance), thermal insulation and mechanical protection.

The coating element 1 comprises a first female end 4a, associated to the main portion 3, arranged to involve externally and tangentially at least one end portion of a first coating element adjacent to the coating element 1 (the term "adjacent" can be understood as "consecutive", "sequential" or "side-by-side"). Said first adjacent coating element can be of the curved or straight kind, which represents an improvement in usability in relation to the currently-known techniques as explained previously.

In a first constructive variation of this first preferred embodiment, a first female end 4a has an angular gap capable of allowing an angular deflection θ between said end portion of said first adjacent coating element and the first female end 4a of the coating element 1 , as can be seen in figures 3 and 4.

In a second constructive variation of this first preferred embodiment, the first female end 4a has a semi-spherical arrangement capable of allowing an angular deflection θ between the end portion of said first adjacent coating element and the first female end 4a of the coating element 1 , as can be seen in figures 5 and 6. Said semi-spherical arrangement provides an interference between the parts (end portion of said first adjacent coating element and the first female end 4a), similarly to an articulating knuckle, allowing the angle between them to be adjusted in order to obtain the necessary curvature.

Analogously, in this second variation, the male end 5 has a semi- spherical arrangement capable of allowing an angular deflection θ between the end portion of said second adjacent coating element and the male end 5 of the coating element 1.

In other words, this angular gap or this semi-spherical arrangement allows a slanted accommodation of said end portion of said first adjacent coating element in the first female end 4a and/or in the male end 5, so as to enable the sequential coating elements to be angled together in a simple, practical, efficient and optimized manner, providing a greater level of protection.

Preferably, said slanted accommodation consists of an accommodation with angular deflection θ of the order of 2 geometric degrees compared to a straight accommodation. In a possible installment, a plurality of sequential coating elements 1 can be used so as to obtain the coating of straight sections and even a curve of the order of 45 geometric degrees on a bar 12 m in length, which allows great design flexibility and implementation contrary to the techniques known today, which do not allow a curvature greater than 5 geometric degrees.

In this first preferred embodiment, the coating element 1 also comprises a male end 5 arranged to be involved externally and tangentially by an end portion of a second adjacent coating element, such that the coating element 1 is disposed between said first adjacent coating element and said second adjacent coating element. Preferably, the said second adjacent coating element presents the same constructive disposition of the coating element 1 , object of the present invention, and, accordingly, said end portion of said second adjacent coating element presents the same constructive disposition of the first female end 4a. The term "female" is also known as "pocket" and the term "male" is also known as "tip".

Further according to figure 1 , the first female end 4a of the coating element 1 has a receptor opening 6 and the male end 5 has an injector opening 7, and the receptor opening 6 has a cross section with an area greater than the area of a cross section of the injector opening 7 (important note: to avoid any kind of confusion, the expression "cross section" refers to a planar section perpendicular to the plane formed by the axes x and y shown on the drawings). Said receptor opening 6 is capable of accommodating said first adjacent coating element by mechanical interference.

Preferably, the receptor opening 6 and the injector opening 7 have a substantially circular format, and the radius of the receptor opening 6 is greater in relation to the radius of the injector opening 7.

Hence, the first female end 4a of the coating element 1 is arranged dimensionally to involve tangentially and externally said end portion of said first adjacent coating element. This sizing consists of providing a suitable thickness and radius to permit the fitting in and fastening of the first female end 4a of the coating element 1 on the said end portion of said first adjacent coating element. Said thickness of the first female end 4a of the coating element 1 should be sufficient to provide resistance to the joint against tears and punctures without impairing the performance of the welding. The radius of the first female end 4a of the coating element 1 should be adjusted so that the first female end 4a is tangentially and externally juxtaposed to said end portion of said first adjacent coating element.

A first female end 4a of the coating element 1 and said end portion of said first adjacent coating element are welded together by electrofusion. Analogously, the male end 5 of the coating element 1 and said end portion of said second adjacent coating element are welded together by electrofusion.

Welding by electrofusion consists of a technique often used to join ducts (tubes) made of polyethylene. In general terms, the welding is applied to a part or connector normally cylindrical, having an internal resistive electrical element to which a controlled electrical voltage is applied to generate heat by joule effect, in order to weld the inner wall of the connector to the outer wall of the duct that is inserted therein. Subsequently, the electric current is interrupted in order to permit cooling of the connector and the duct, and, consequently, the welding between both. The application of the electrical voltage on the connector is done by means of electrofusion welding equipment, the voltage or current of which is controlled and compulsorily less than 50 V, in order to guarantee the safety of the operator. Said equipment and connectors are described in international and domestic norms, such as EN 1555, EN 12201 and NBR 14463, among others.

Accordingly, the first female end 4a and/or the male end 5 has/have electrical resistances 8 and electrical connection pins 13 capable of allowing the association of adjacent coating elements by welding by electrofusion. Said electrical resistances 8 preferably have a circular format that accompanies the circumference of the coating element 1. The material of the electrical resistances 8 can be copper or special alloys, depending on the resistance value needed for correct fusion, which is in accordance with the length and sizes of the joint.

As illustrated in figure 6, this welding by electrofusion is made possible by means of welding equipment 14, which is associated to the coating element 1 by way of electrical connection pins 13 comprised by the coating element 1 itself. It should be noted that the welding allows an adherence and avoids movements between the coating element 1 and the steel ducts 2, contrary to the thermoretractile blankets used in the state of the art.

Preferably, the coating element 1 also comprises at least one injectable hole 9 disposed between the first female end 4a and the male end 5, capable of allowing the injection of a polyurethane foam the function of which is to provide thermal insulation for the service duct. The injectable hole 9 is sealed by means of a buffer 15 by thermoplastic welding. The coating process for service ducts 2 by means of a coating element 1 according to a first preferred embodiment of the present invention comprises the following steps:

i) mount the service duct 2 on an assembly support 10. This assembly support 10 comprises a tubular pin 16 circular in format with a diameter slightly less than that of the service duct 2, so as to enable it to be fitted in in a safe and stable manner. This step is illustrated in figure 3;

ii) install spacers 11 along the service duct 2 distanced apart according to pre-established parameters. This step is illustrated in figure 4;

iii) coat the service duct 2 with at least one coating element 1 on the spacers 11. This step is illustrated in figure 4;

iv) coat the service duct 2 with at least one first coating element adjacent to the coating element 1 on the spacers 11 , where said first adjacent coating element has an end portion. This step is illustrated in figure 4;

v) accommodate said end portion of said first adjacent coating element on the first female end 4a of the coating element 1. Said accommodation can be slanted or straight, as described previously. This step is illustrated in figure 4;

vi) adjust the angular deflection between said end portion of said first adjacent coating element and a first female end 4a of the coating element 1. This step is illustrated in figure 4;

vii) fix metallic clamps 12 around the first female end 4a of the coating element 1 and/or of said end portion of said first adjacent coating element. This step is illustrated in figure 5;

viii) weld by electrofusion the first female end 4a of the coating element 1 and said end portion of said first adjacent coating element. The electrofusion welding machine, the voltage of which varies between 5 and 50 Volts (continuous or alternating current), is applied precisely on the electrical resistances 8 by way of electrical connection pins 13. This step is illustrated in figure 6;

ix) inject polyurethane foam between the coating element 1 and the service duct 2 or between said first adjacent coating element and the service duct 2 by way of an injectable hole 9 comprised by the coating element 1 and/or by said first adjacent coating element, providing thermal insulation on the joint. Said injectable hole 13 is subsequently sealed by means of a buffer 15 and thermoplastic welding. This step is illustrated in figure 7.

SECOND PREFERRED EMBODIMENT

Figures 8 and 9 illustrate a coating element 1 capable of coating curved service ducts 2 according to a second preferred embodiment of the present invention.

In this second embodiment, the coating element 1 comprises a first female end 4a and a main portion 3 substantially dome shaped (convex) associated together, where the first female end 4a has characteristics as already described above in the first preferred embodiment. Hence, in this second preferred embodiment, the coating element 1 is curved.

Additionally, the coating element 1 comprises, instead of a male end, a second female end 4b arranged to involve externally and tangentially at least one end portion of a second coating element adjacent to the coating element 1.

It is important to note that the second female end 4b comprises the same characteristics and constructive disposition/arrangement as the first end 4a described previously and, therefore, they shall not be detailed again.

This being the case, the second female end 4b of the coating element 1 has an angular gap capable of allowing an angular deflection between said end portion of said second adjacent coating element and the second female end 4b of the coating element 1.

Further, the second female end 4b of the coating element 1 and said end portion of said second adjacent coating element are welded together by electrofusion, where said second adjacent coating element can be of the curved or straight kind.

Preferably, the second female end 4b has electrical resistances 8 capable of allowing the association of adjacent coating elements by electrofusion welding.

The coating process for service ducts 2 by means of a coating element 1 according to a second preferred embodiment of the present invention comprises the following steps, besides steps i to ix already described for the first preferred embodiment:

x) coat the service duct 2 with at least one second coating element adjacent to the coating element 1 on the spacers 11 , where said second adjacent coating element is curved or straight and has an end portion. This step is illustrated in figure 10;

xi) accommodate said end portion of said second adjacent coating element in the second female end 4b of the coating element 1. Said accommodation can be in a slanted or straight manner, as described previously. This step is illustrated in figure 10;

xii) adjust the angular deflection between said end portion of said second adjacent coating element and the second female end 4b of the coating element 1. This step is illustrated in figure 10;

xiii) fix metallic clamps 12 around the second female end 4b of the coating element 1 and/or of said end portion of said second adjacent coating element. This step is illustrated in figure 11 ;

xiv) weld by electrofusion the second female end 4b of the coating element 1 and said end portion of said second adjacent coating element. The welding machine by electrofusion, the voltage of which varies between 5 and 50 Volts (continuous or alternating current), is applied precisely on the electrical resistances 8 by way of electrical connection pins 13. This step is illustrated in figure 12; and

xv) inject polyurethane foam between the coating element 1 and the service duct 2 or between said second adjacent coating element and the service duct 2 by way of an injectable hole 9 comprised by the coating element 1 or by said second adjacent coating element, providing thermal insulation on the joint. Said injectable hole 13 is subsequently sealed by means of a buffer 15 and thermoplastic welding. This step is illustrated in figure 13. Preferably, steps x to xiv occur prior to steps i to viii.

It is important to point out that the constructive disposition/arrangement of the coating element 1 according to the second preferred embodiment allows a more accentuated bend in relation to the coating element 1 according to the first preferred embodiment. Accordingly, it is possible to implement a first or a second preferred embodiment according to the need demanded by each specific application.

Having described examples of preferred embodiments, it must be understood that the scope of the present invention encompasses other potential variations, and is only limited by the content of the claims appended hereto, other potential equivalents being included therein.

Claims

o CLAIMS

1. Coating element (1), particularly for coating curved or straight service ducts (2), the coating element (1) being characterized by comprising a first female end (4a) arranged to involve externally and tangentially at least one end portion of a first coating element adjacent to the coating element (1), the first female end (4a) of the coating element (1) and said end portion of said first adjacent coating element being welded together by electrofusion.

2. Coating element (1) according to claim 1 , characterized in that the coating element (1) has at least one main portion (3) associated to the first female end (41), the main portion (3) being substantially dome-shaped.

3. Coating element (1) according to claim 1 or 2, characterized in that said first adjacent coating element is curved or straight.

4. Coating element (1) according to any of the prior claims, characterized by comprising a male end (5) arranged to be involved externally and tangentially by an end portion of a second adjacent coating element, the male end (5) of the coating element (1) and said end portion of said second adjacent coating element being welded together by electrofusion.

5. Coating element (1) according to claim 4, characterized in that said second adjacent coating element is curved or straight.

6. Coating element (1) according to claim 5, characterized in that the first female end (4a) has a receptor opening (6) and the male end (5) has an injector opening (7), a receptor opening (6) having a cross section with a larger area compared to the area of a cross section of the injector opening (7), a receptor opening (6) being capable of accommodating said first adjacent coating element by interference.

7. Coating element (1) according to claim 6, characterized in that the receptor opening (6) and the injector opening (7) is substantially circular in shape, the radius receptor opening (6) being greater in comparison with the radius of the injector opening (7).

8. Coating element (1) according to according to claim 4, characterized in that the first female end (4a) and/or a male end (5) has/have electrical resistances (8) and electrical connection pins (13) capable of allowing the association of adjacent coating elements by welding by electrofusion.

9. Coating element (1) according to claim 1 , 2, or 3, characterized by comprising a second female end (4b) arranged to involve externally and tangentially at least one end portion of a second coating element adjacent to the coating element (1), the second female end (4b) of the coating element (1) and said end portion of said second adjacent coating element being welded together by electrofusion, said second adjacent coating element being curved or straight.

10. Coating element (1) according to claim 9, characterized in that the second female end (4b) has electrical resistances (8) capable of allowing the association of adjacent coating elements by welding by electrofusion.

11. Coating element (1) according to claim 1 , 2 or 3, characterized in that the first female end (4a) has an angular gap capable of allowing an angular deflection (θ) between the end portion of said first adjacent coating element and the first female end (4a) of the coating element

(1).

12. Coating element (1) according to claim 9 or 10, characterized in that the second female end (4b) has an angular gap capable of allowing an angular deflection (θ) between the end portion of said second adjacent coating element and the second female end (4b) of the coating element (1).

13. Coating element (1) according to claim 11 or 12, characterized in that the angular deflection (θ) is of the order of 2 geometric degrees compared to a straight accommodation.

14. Coating element (1) according to claim 1 , 2 or 3, characterized in that the first female end (4a) has a semi-spherical arrangement capable of allowing an angular deflection (θ) between the end portion of said first adjacent coating element and the first female end (4a) of the coating element (1).

15. Coating element (1) according to claims 4 and 14, characterized in that the male end (5) has a semi-spherical arrangement capable of allowing an angular deflection (θ) between the end portion of said second adjacent coating element and the male end (5) of the coating element

(1)- 16. Coating element (1) according to claim 14 or 15, characterized in that the angular deflection (θ) is of the order of 2 geometric degrees compared to a straight accommodation.

17. Coating element (1) according to any of the prior claims, characterized by comprising at least one injectable hole (9) capable of allowing the injection of a polyurethane foam between the coating element (1) and the service duct (2).

18. Coating element (1) according to any of the prior claims, characterized by comprising polyolefin.

19. Coating process for curved or straight service ducts (2), characterized by comprising the following steps:

i) mount the service duct (2) on an assembly support (10);

ii) install spacers (11) along the service duct (2);

iii) coat the service duct (2) with at least one coating element (1) on the spacers (11), the coating element (1) having at least one first female end (4a);

iv) coat the service duct (2) with at least one first coating element adjacent to the coating element (1) on the spacers (11), said first adjacent coating element being curved or straight and having an end portion;

v) accommodating said end portion of said first adjacent coating element on the first female end (4a) of the coating element (1 );

vi) adjust the angular deflection between said end portion of said first adjacent coating element and a first female end (4a) of the coating element (1);

vii) fix metallic clamps (12) around the first female end (4a) of the coating element (1) and/or of said end portion of said first adjacent coating element; and

viii) weld by electrofusion a first female end (4a) of the coating o

element (1) and said end portion of said first adjacent coating element.

20. Coating process according to claim 19, characterized by comprising an additional step ix) inject polyurethane foam between the coating element (1) and the service duct (2) or between said first adjacent coating element and the service duct (2) by way of an injectable hole (9) comprised by the coating element (1) or by said first adjacent coating element.

21. Coating process according to claim 19 or 20, the coating element (1) having at least one second female end (4b), the process being characterized by comprising the following additional steps:

x) coat the service duct (2) with at least one second coating element adjacent to the coating element (1) on the spacers (11), said second adjacent coating element being curved or straight and having an end portion;

xi) accommodating said end portion of said second adjacent coating element on the second female end (4b) of the coating element (1);

xii) adjust the angular deflection between said end portion of said second adjacent coating element and a second female end (4b) of the coating element (1);

xiii) fix metallic clamps (12) around the second female end (4b) of the coating element (1) and/or of said end portion of said second adjacent coating element; and

xiv) weld by electrofusion the second female end (4b) of the coating element (1) and said end portion of said second adjacent coating element.

22. Coating process according to claim 21 , characterized by comprising an additional step xv) inject polyurethane foam between the coating element (1) and the service duct (2) or between said second adjacent coating element and the service duct (2) by way of an injectable hole (9) comprised by the coating element (1) or by said second adjacent coating element.