"Axial expansion compensating piping component, and installation implementing it"

Abstract

The invention relates to a piping component (1) for a high-temperature fluid (8) circulation circuit (81, 82), particularly for liquid metal or molten salt, especially liquid sodium at 550°C. This component comprises two inner (12) and outer (11) sleeves inserted one inside the other, defining between them a static, non-circulating space (100) communicating with the circulating fluid (8) but thermally separated. These sleeves are connected to each other by an axially deformable bellows (13) to compensate for axial expansion of the piping (81, 82) of said circuit. This outer sleeve (11) has, in the sagittal plane, radially extreme points (111, 112) which receive drain ports and are all outside the bellows (13).The bellows can empty by gravity: this results in a more complete purge, with better removal of allogeneic residues present in the heat transfer fluid. Preferably, the compensating bellows (13) is concentric and internal to the external sleeve (11), receiving the pressure on its "external" surface. Figure for the abbreviation: Fig. 2.

Description

Title of the invention: "Axial expansion compensating piping component, and installation implementing it"

[0001] The present invention relates to a piping component for compensating axial expansions within a high-temperature fluid circulation circuit, of the axially deforming bellows type.

[0002] It also relates to a fluid circulation installation within a piping circuit, in particular metallic, in particular operating in an ambient temperature below 50°C, intended for a fluid circulating at a temperature above 400°C, in particular above 450°C or even above 500°C and for example at 550°C, in which said circuit includes one or more compensating components. State of the art

[0003] In areas where a high-temperature fluid is circulated in pipes, particularly metallic pipes, expansions occur between the cold state at ambient temperature (where the circuit is not in operation) and the high-temperature operating state.

[0004] Such fields include, for example, technologies where a molten metal or salt is circulated as a heat transfer fluid, particularly in certain power plants. But they can also include other fields such as those using liquid aluminum for hot coating or injection molding. In such fields, the circulating fluid reaches temperatures of up to 550°C for liquid sodium, or even 600°C or more in some projects, while the minimum temperature is around 20°C when the circuit is at ambient temperature during a prolonged shutdown of circulation.

[0005] To prevent leaks or damage to the circuit, it is often necessary to compensate for axial expansion in one way or another. The usual method consists of absorbing these length variations by bending the angled components. If necessary, for example for long lengths, a compensating bracket can be inserted. However, these solutions take up a lot of space, and such bending is sometimes impossible or insufficient when the pipe wall is thick or the pipe diameter is large.

[0006] For these reasons, it has been proposed to use piping components that provide compensation by axial displacement using an axially deformable bellows. However, this type of bellows must be specifically dimensioned to ensure its mechanical resistance to operating conditions in order to take into account taking into account the damaging deformations that occur at high temperatures, to guarantee the resistance of materials to pressure and fatigue, as well as their stability during finishing.

[0007] In order to limit the effects of high temperatures, it has been proposed to provide active cooling by circulating cold fluid around the deformation zones, but this would entail unacceptable risks in the event of failure of the cooling system.

[0008] Various passive configurations have been proposed, which consist of implementing thermal insulation of the bellows from the piping and using the ambient environment to passively cool the bellows. This may involve placing the bellows in a position where the fluid it contains is sufficiently far from the circulating fluid (hot source) to remain at a temperature lower than that of the circulating fluid, preferably below the melting temperature of the bellows material(s), for example below 400°C, and for example around 300°C in document GB1242986, illustrated here in [Fig. 1].

[0009] In this configuration, as proposed in document GB1242986, the interior of the piping 10, 20 is connected by an annular circulation space 40 to a static space 42 which receives the fluid but does not participate in its circulation. This static space is cylindrical and surrounds the circulation piping 10, from which it is separated by a layer of insulation 14, while being cooled by the ambient atmosphere, in particular by means of cooling fins 24. In its portion furthest from the circulation space 40, the static space 42 is surrounded by a bellows 30 with annular corrugations, which deforms axially when one of the piping 10 moves longitudinally relative to the other 20. In its peripheral portion, this insulating sleeve 14 includes heating wires 15 to heat the liquid layer during temperature control.The bellows is cooled by the outside atmosphere, and the heat flow which reaches it by conduction from the circulation space 40 is pre-cooled by the fins 24.

[0010] However, it remains desirable to improve this type of component, particularly in terms of reliability, lifespan and ease of implementation and maintenance, especially in the context of use with a liquid metal.

[0011] One object of the invention is to overcome, in whole or in part, the disadvantages of the state of the art, and in particular to improve the performance of simplicity of manufacture, flexibility of adaptation to constraints, but also of reliability, lifespan, and ease of maintenance. Presentation of the invention

[0012] The invention provides a piping component for a fluid circulation circuit designed to vary between a minimum and a maximum temperature, comprising: - a circulation space designed to allow passage for said fluid circulation between a first inlet and a second inlet, - an inner sleeve and an outer sleeve inserted one inside the other to define between them a so-called static space which is not traversed by said fluid circulation and is thermally distant from said circulation space, thus allowing said static space to have a temperature lower than that of the fluid circulating in said circuit when the temperature of the circulating fluid is higher than the ambient temperature, which inner and outer sleeves: • are each connected in a sealed manner to one of the said first and second inlets, so as to allow passage of said fluid between said static space and said circulation space, in at least one region called the connection region, and • are connected to each other in a sealed manner by at least one axially deformable bellows, called a compensating bellows, which is arranged to accept an axial elastic deformation enabling compensation of a variation in the axial gap between the first inlet and the second inlet, relative to each other, caused by an axial expansion of the piping of said circulation circuit when the temperature of the circulating fluid varies between said minimum temperature and said maximum temperature.

[0013] According to the invention, said outer sleeve has a shape in which, along at least one plane sagittal to it, the radially extreme points of its inner wall are all located outside the parts of said bellows intended to absorb the elastic deformation producing said expansion compensation, so that said radially extreme points form the totality of the low points and / or high points of said static space when said component is installed with said sleeves in an axially horizontal position.

[0014] This external sleeve has, by way of example, a substantially cylindrical shape with a radial bulge or flare, or a slightly conical or biconical shape, or any shape widening radially continuously towards one or more radially extreme points.

[0015] Preferably, the radially extreme point(s) of the outer sleeve each include a fluid connection arranged to allow connection to: a liquid drain connection at a low point, and / or a gas purge connection at a high point.

[0016] Typically, the compensating bellows is arranged inside the outer sleeve, and in particular concentrically with the inner sleeve or forming said inner sleeve itself.

[0017] Although the cooling of the bellows may be, in an equal context of materials and exchange surfaces, less than that permitted by the external bellows of the prior art, and / or more complex to install or monitor or repair, this arrangement in the invention makes it possible to guarantee that no retention space remains in the compensator.

[0018] Indeed, all the low points of the bellows in contact with the liquid, that is to say the bottom of the waves of the upper part of the bellows, can empty by gravity by following the periphery of the bellows to the waves of the lower part of the bellows, which empty by gravity to the low point of the inner wall of the outer sleeve, where one or more tapping points of the purge circuit can be installed without compromising the solidity of the bellows.

[0019] The invention thus makes it possible to obtain a more complete purging of the liquid, particularly at the compensator, and therefore better removal of all chemical compounds and allogeneic residues included in and transported by the heat transfer fluid; which are a factor in corrosion of the walls and / or a decrease in fluid performance if they accumulate there, particularly in a concentrated form in small retention areas. In the case of piping conveying liquid sodium, the presence of stagnant areas also constitutes a risk during maintenance operations for the safety of the installation due to the reactivity of sodium with water and air. As can be understood, this avoids this type of retention and accumulation, which existed, for example, in the lower part of the lower corrugations of the bellows in the prior art document of [Fig. 1].Furthermore, in the case of liquids presenting risks of interaction during maintenance, such as sodium, this allows the component to be inert by ensuring that it no longer contains (or contains less) potentially reactive liquid.

[0020] It should be noted that the bellows of the invention, when it forms part of the inner surface of the static space, i.e., the side facing the piping, receives the pressure on its outer surface, i.e., it operates "under external pressure," i.e., on the convex side of its circumference. It turns out that, for the same bellows, operating under external pressure provides it with better resistance, both instantaneous and over time, to fatigue, than when it operates under "internal pressure," as is the case in the prior art configuration of document GB1242986A.

[0021] Furthermore, the expansion of the pipes then leads to tensile stress on this bellows, which also proves to be more favorable (at least in combination with the pressure). external) than when it works in axial compression as is the case in the prior art configuration of document GB1242986A.

[0022] This configuration of the invention thus makes it possible to avoid certain modes of instability encountered in the case of bellows working under internal pressure and subjected to axial compression.

[0023] Typically, in the component of the invention, the internal and external sleeves are arranged to radially surround the first and second inlets and / or the piping to which they are connected.

[0024] Preferably, the part of the static space which is in contact with the inner wall of the compensation bellows, called the compensation space, communicates with the circulation space by means of an intermediate space which is axially elongated with respect to the inner and outer sleeves and thermally distant from said circulation space, thus creating a "thermal brake" in an axial direction for a heat flow established within the fluid between the circulation space and said compensation space, in particular in the form of a static liquid sheet surrounding the inner sleeve and thermally distant from the circulation space.

[0025] According to an optional feature, the inner sleeve is surrounded, inside the static space, by a thermally insulating sleeve which covers the connection region and extends towards the compensation bellows, thus delimiting an elongated and thin liquid blade forming a thermal brake between the connection region and the compensation bellows, regardless of the radial gap existing between the inner sleeve and the outer sleeve.

[0026] According to another feature, which may or may not be combined with the previous optional features, the component comprises at least two compensation bellows, in particular arranged inside the same external sleeve, whose compensation spaces are part of the same static space and are arranged on either side of the connection region of said static space.

[0027] According to another aspect, the invention proposes a fluid circulation installation within a piping circuit, in particular metallic, in particular operating in an ambient temperature below 50°C, intended for a fluid circulating at a temperature above 400°C, in particular above 450°C or even 500°C, in particular below 600°C and for example around 550°C.

[0028] According to this aspect, said circuit comprises one or more piping components as described herein, which is implemented to achieve compensation for all or part of the axial expansion of the piping of said circuit.

[0029] According to optional features of this installation, intended to be combined together in different ways: • the compensating component (1, 1', 1", 1"') is mounted so that the expansion of the pipes (81, 82) of the circuit tends to axially compress, during their temperature rise, the bellows (13, 13') of said compensating component; • the circulating fluid is or includes a liquid salt or liquid metal, in particular is or includes liquid sodium; and / or • such an installation in which the circulating fluid is or includes liquid sodium; and / or • such an installation in which the fluid is used as a heat transfer fluid.

[0030] Various embodiments of the invention are provided, incorporating, according to all their possible combinations, the different optional features set out here. Brief description of the drawings

[0031] Other features and advantages of the invention will become apparent from the detailed description of a non-limiting embodiment, and from the accompanying drawings in which:

[0032] [Fig-1]: [Fig.1] is a cross-sectional diagram of an axial and vertical component bellows compensation according to the state of the art, taken from the illustration figure in document GB1242986A;

[0033] [Fig.2] : [Fig.2] illustrates a first example of an embodiment of the invention, by an axial and vertical cross-section diagram of a compensating component with an offset bellows mounted inside an external sleeve substantially cylindrical and coaxial to the piping;

[0034] [Fig.3]: [Fig.3] is a half-view of [Fig.2], obtained by axisymmetric thermal calculation and which illustrates the temperature variations within the component of [Fig.2], for a fluid circulating at 550°C under the assumption of a static fluid, with purely conductive heat exchange;

[0035] [Fig.4]: [Fig.4] illustrates a second example of an embodiment of the invention, by an axial and vertical cross-section diagram of a compensating component with two offset bellows mounted symmetrically inside an external sleeve substantially cylindrical and coaxial to the piping;

[0036] [Fig.5]: [Fig.5] illustrates a third example of an embodiment of the invention, by an axial and vertical cross-sectional diagram of a compensating component with an offset bellows mounted inside an external sleeve substantially cylindrical and coaxial to the piping, and including a thermally insulating intermediate sleeve;

[0037] [Fig.6]: [Fig.6] illustrates a fourth example of an embodiment of the invention, by an axial and vertical cross-sectional diagram of a compensating component with two offset bellows mounted symmetrically inside an external sleeve substantially cylindrical and coaxial to the piping, and each including a thermally insulating intermediate sleeve. Description with reference to the figures

[0038] Figure 2 illustrates a first example of an embodiment of the invention. The other examples of embodiments will only be described in terms of their differences.

[0039] In this first embodiment, the axial expansion compensating component 1 comprises a first coaxial inlet 181 and a second coaxial inlet 182, through which the compensating component is connected in series to the circulation circuit of a heat transfer fluid, and through which the circulation space 108 of this circuit passes. This is, for example, liquid sodium 8 circulating at a temperature of up to 550°C. For this purpose, the component 1 is interposed between a first pipe 81 and a second pipe 82 of the circulation circuit of this heat transfer fluid, which are thermally insulated by insulating sleeves 811 and 821 from the ambient atmosphere, for example the Earth's atmosphere or the interior atmosphere of a building, the temperature of which typically varies between -10°C and 40°C, and in particular between 10°C and 30°C.

[0040] The first inlet 181 extends radially outwards by way of a first annular flange 118 to an external sleeve 11, which is here substantially cylindrical and coaxial with the two inlets 81, 82. The second inlet 82 extends radially outwards by way of a second annular flange 128 to an internal sleeve 12, which is here substantially cylindrical and coaxial with the two inlets 81, 82. Between these first and second inlets 181, 182, these two annular flanges delimit a so-called connecting space 101.

[0041] On the side opposite the connection space, the inner sleeve 12 is extended by an axially deformable bellows 13 formed by a succession of annular waves. At its end opposite the connection space, the bellows 13 connects via a third annular flank 123 to the end of the outer sleeve 11, thus sealing the casing of the compensating component 1.

[0042] The bellows 13 is arranged to be able to absorb, by bending the annular waves it comprises, the differences in longitudinal position of the first 181 and second 182 inlets relative to each other, for example in the form of a variation of the gap E812 between the first 118 and the second 128 annular flank of the connection space 101. Typically, if the component is mounted cold, the expansion of the pipes 81, 82 of the circuit will cause a decrease in this gap E812, and therefore an axial tension on the bellows 13.

[0043] The circulation space 108 of the piping thus communicates with the connection space 101, with the so-called intermediate space between the two sleeves 11, 12, and with the so-called compensation space between the bellows 13 and the external sleeve 11, which form a so-called static space 100. Although the heat transfer fluid can thus spread in this static space 100, the volume in it does not circulate in normal operation and is not heated by the liquid circulating 8 in the piping.

[0044] The static space is further thermally separated from the circulation space 108 by the annular static liquid layer of the connecting space and by the cylindrical static liquid layer of the intermediate space. These static liquid layers are cooled by the external atmosphere; their length constitutes a thermal brake, maintaining a thermal gradient between the temperature of the circulating fluid 8 and the compensation space 103, and in particular the bellows 13.

[0045] Indeed, thermal resistance is characterized by axial thermal conduction between the hot source (constituted by the circulation space 108) and the cold source (ambient air). Given the ratio of thermal conductivities between the circulating fluid 8 (particularly in the case of a metallic fluid) and the casing (particularly the external sleeve 11) associated with its possible thermal insulation 110, heat transfer is primarily carried out by the fluid in the intermediate space 102. The thermal resistance equivalent to axial thermal conduction can be approximated by the relation: ], with Re and Ri the external rays ît (Re2-J«2) A and internal to the thermal brake, ! the length of the fluid layer and A the thermal conductivity of the fluid. This thermal resistance is therefore all the higher (and thus more effective) the closer the ratio is to 1, that is to say, the thinner the liquid layer, and Ri that the length 1 of the fluid blade is large. In this calculation, the fluid is considered static; therefore, the heat exchange within the fluid is purely conductive.

[0046] Thus, as illustrated in [Fig. 3], in the case of a fluid circulating at 550°C, this thermal gradient allows the temperature to drop to 400°C at the inlet of the static space, which allows the bellows 13 to remain at an even lower temperature and improve its lifespan.

[0047] In a vertical axial plane, the outer sleeve 11 has two and only two radially extreme points, which can be seen to be located outside the compensating bellows 13. One 111 constitutes a high point (or possibly a horizontal line of high points), and has a tapping point 116 which can be opened or closed outwards, thus allowing for easier gas purging of the component 1, for example, during circuit filling. The other 112 constitutes a low point (or possibly a horizontal line of low points), and carries a tapping point 117 which can be opened or closed outwards, thus allowing a complete liquid draining of the compensating component 1, and therefore a good evacuation of the used liquid and the allogeneic residues it may contain.

[0048] Regarding the bellows 13, it will be noted that all the low points of the waves 131 of its upper part can empty by gravity by following the periphery of the bellows to the waves of the lower part 132 of the bellows, which do not have any low points since they can empty by gravity to the low point 112 of the inner wall of the outer sleeve 11.

[0049] The parts constituting the sealed casing, in particular the bellows, the external and internal sleeves and the blanks, are typically made of materials such as stainless steel (for example 316L) or its alloys, or Inconel, or titanium, or an alloy including these materials, or any material known to be suitable for the temperature and pressure conditions involved. They are preferably assembled by welding, in particular according to one or more processes known in this field and for these materials.

[0050] The insulating parts are for example made of rock wool, or of materials known to be suitable for these conditions.

[0051] For example, in a sodium-based heat transfer fluid circulation system, particularly for a secondary circuit in a power plant, the piping typically represents one or several hundred meters in length and is typically around 700 mm in diameter. The expansion joint component then has similar dimensions for the first and second inlets, and an external sleeve with a diameter of around 1000 mm. Second example of a method of implementation

[0052] A second embodiment of the invention is illustrated in [Fig. 4], in which the compensator 1' comprises a first compensating bellows 13 similar to that of the component in [Fig. 2] and a second bellows 13' on a second internal sleeve 12' mounted on the opposite side to the first 13, 12 with respect to the connecting space 101. Inside the same external sleeve 11, this component 1' thus comprises a second intermediate space 102' and a second compensating space 103', forming a common static space 100. Preferably, for example for improved mechanical performance, the second bellows and sleeves are identical to the first and mounted symmetrically.

[0053] The two sleeves are then connected in a sealed manner with the first 181 and the second 182 inlets: the internal sleeves 12 and 12' are connected directly with the second inlet 182 and respectively the first inlet 181, while the external sleeve 11 is connected to these two inlets indirectly via the bellows 13, 13' and the internal sleeves 12, 12'. Similar to the previous examples, these connections allow the passage of fluid between the static space 100 and the circulation space 108 at the same connection region 101.

[0054] This type of configuration allows, for example, greater compensation capacity with a single component and therefore a single assembly in the circuit. This can be advantageous, for instance, to avoid having to use a longer bellows, which represents a significant constraint during manufacturing. Third example of an embodiment

[0055] A third example of an embodiment of the invention is illustrated in [Fig.5]. Compared to the structure of that of [Fig.2], the component 1" of this third example has an internal sleeve 12 of a smaller diameter, allowing for example a larger gap D12 with the external sleeve 11, but also which has a simpler shape.

[0056] Around the inner sleeve 12, this component 1" further comprises a thermally insulating intermediate sleeve, which is connected to the first connecting flange 118 so as to limit or even prevent liquid communication between, on the one hand, the circulation spaces 108 and the connecting space 101 and, on the other hand, the so-called external intermediate part 105 of the static space 100. The presence of this "intermediate" insulating sleeve 14 thus delimits, between the connecting space 101 and the compensation space 103, an intermediate space called the internal space 104 which is radially reduced compared to the gap between the inner sleeve 12 and the outer sleeve 11. This reduction thus limits the thickness of the liquid layer circulating in it, and also thereby limits the heat flow circulating in it. Compared to the configuration of [Fig.2], we thus obtain a shape imposing less constraint on the manufacture and / or assembly of these sleeves 11, 12 and of the compensating component 1" itself, while making possible a thin internal liquid blade 104 which preserves or even improves the efficiency of the improved thermal brake between the circulating fluid 8 and the bellows 13. .

[0057] In this example, the outer sleeve 11 carries optional cooling fins 1101, here welded in a longitudinal position. It should be noted that these optional fins are also provided for the other embodiments. Fourth embodiment

[0058] A fourth example of an embodiment of the invention is illustrated in [Fig.6], with a component 1'" which has, in relation to that of [Fig.5], the same modifications as that of [Fig.4] in relation to that of [Fig.2]: the compensation structure with insulating intermediate sleeve 14 is doubled and distributed on both sides of the connection space 101, with similar advantages.

[0059] Of course, the invention is not limited to the examples just described and many modifications can be made to these examples without departing from the scope of the invention. Nomenclature (Fig. 2 to Fig. 6)

[0060] 1,1',1",1"' expansion compensating component

[0061] 100 static space

[0062] 101 connection region

[0063] 102, 102' intermediate space

[0064] 103 compensation space

[0065] 104 internal intermediate space, internal liquid layer

[0066] 105 external intermediate part

[0067] 108 circulation space

[0068] 11 outer sleeve

[0069] 110 thermal insulation of the envelope

[0070] 1101 longitudinal cooling fins

[0071] 111, 112 radially extreme points, top and bottom points

[0072] 116 gas purge connection (high point)

[0073] 117 Liquid drain connection (lowest point)

[0074] 118, 128 first and second connecting blanks

[0075] 12, 12' inner sleeve

[0076] 123 third end

[0077] 13, 13' compensating bellows

[0078] 131 vertically superior waves of the bellows

[0079] 132 vertically lower waves of the bellows

[0080] 14 thermally insulating intermediate sleeve

[0081] 181 first entry

[0082] 182 second entry

[0083] 8 circulating fluid

[0084] 81 first piping

[0085] 811 insulation of the first pipe

[0086] 82 second piping

[0087] 821 insulation of the second pipe

[0088] D12 gap between the inner and outer sleeves

[0089] E812 axial deviation caused by thermal expansion of the pipes

Claims

1. Demands Piping component (1, 1', 1", 1"') for a fluid circulation circuit (81, 82) (8) intended to vary between a minimum and a maximum temperature, comprising: - a circulation space (108) intended to be crossed by said fluid circulation between a first inlet (181) and a second inlet (182); - an inner sleeve (12) and an outer sleeve (13) inserted one inside the other to define between them a so-called static space (100) which is not traversed by said fluid circulation and is thermally distant from said circulation space (108), thus allowing said static space to have a temperature lower than that of the fluid circulating in said circuit when the temperature of the circulating fluid (8) is higher than the ambient temperature, which inner and outer sleeves: • are connected in a sealed manner with the first (181) and second (182) inlets, in particular the outer sleeve (11) with the first inlet (181) and the inner sleeve (12) with the second inlet (182), so as to permit passage of said fluid between said static space (100) and said circulation space (108) in at least one region referred to as the connection region (101), and • are connected to each other in a sealed manner by at least one axially deformable bellows (13), called a compensating bellows, which is arranged to accept an axial elastic deformation allowing to compensate a variation of the axial gap (E812) between the first inlet (181) and the second inlet (182), one with respect to the other, caused by an axial expansion of the piping (81, 82) of said circulation circuit when the temperature of the circulating fluid varies between said minimum temperature and said maximum temperature; said component being such that said outer sleeve (11) has a shape in which, along at least one plane sagittal to it, the radially extreme points (111, 112) of its inner wall are all located outside the parts of said bellows (13) provided to absorb the elastic deformation producing said expansion compensation, so that said radially extreme points (111, 112) form the totality of the low points and / or high points of said static space (100) when said component (1) is installed with said sleeves (11, 12) in an axially horizontal position, the component being characterized in that the radially extreme point(s) (111, 112) of the outer sleeve (11) each include a fluid connection arranged to be able to connect a liquid drain fitting (117) and / or a gas purge fitting (116).

2. Component according to any one of the preceding claims, characterized in that the compensation bellows (13) is disposed inside the outer sleeve (11), and in particular concentrically with the inner sleeve (12) or itself forming said inner sleeve, said compensation bellows thus receiving the pressure on its "outer" surface.

3. Component according to any one of the preceding claims, characterized in that the internal (12) and external (11) sleeves are arranged to radially surround the first (181, 182) and second inlets and / or the piping (81, 82) to which they are connected.

4. Component according to the preceding claim, characterized in that the part of the static space which is in contact with the inner wall of the compensation bellows (13), called compensation space (103), communicates with the circulation space (108) by means of an intermediate space (102) which is axially elongated with respect to the inner (12) and outer (11) sleeves and thermally distant from said circulation space (108), thus creating a thermal brake in an axial direction for a heat flow established within the fluid between the circulation space (108) and said compensation space (103), in particular in the form of a substantially static liquid sheet surrounding the inner sleeve and thermally distant from the circulation space.

5. Component according to the preceding claim, characterized in that the inner sleeve (12) is surrounded, inside the static space (100), by a thermally insulating sleeve (14) which covers the connection region (101) and extends towards at least one compensation bellows (13), thus delimiting inside said insulating sleeve (14) an elongated and thin liquid blade (104) forming a thermal brake between the connection region (101) and the compensation bellows (13), independently of the radial gap (DI2) existing between the inner sleeve (12) and the outer sleeve (11).

6. Component according to the preceding claim, characterized in that it comprises at least two compensation bellows (13, 13'), in particular arranged inside the same external sleeve (11), the compensation spaces (103, 103') of which are part of the same static space (100) and are arranged on either side of the connection region (101) of said static space.

7. Fluid circulation installation (8) within a piping circuit, in particular metallic, in particular operating in an ambient temperature below 50°C, intended for a fluid circulating at a temperature above 400°C, in particular above 450°C or even 500°C, in particular below 600°C and for example around 550°C, characterized in that said circuit comprises one or more compensating components (1, 1', 1", 1'") of piping according to any one of the preceding claims implemented to achieve compensation of all or part of the axial expansion of the piping (81, 82) of said circuit.

8. Installation according to the preceding claim, characterized in that the compensating component (1, 1', 1", 1'") is mounted so that the expansion of the pipes (81, 82) of the circuit tends to axially compress the bellows (13, 13') of said compensating component during their temperature rise.

9. Installation according to the preceding claim, characterized in that the circulating fluid is or comprises a liquid salt or a liquid metal.

10. Installation according to the preceding claim, characterized in that the circulating fluid is or comprises liquid sodium.

11. Installation according to any one of claims 7 to 10, characterized in that the fluid is used as a heat transfer fluid.

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