Thermal insulation device

Abstract

The invention relates to a thermal insulation device comprising: - a metal casing and - several metal sheets stacked sequentially in the thickness direction of the metal casing, the metal sheets comprising: - embossed metal sheets (Ia); - metal support sheets (2a) placed between the embossed metal sheets; each embossed metal sheet has several first embossments (11) having a first height along the thickness direction, the first embossments rest against a metal support sheet adjacent to the embossed metal sheet, each embossed metal sheet has several second embossments (12) having a second height along the thickness direction; the first height is greater than the second height.

Description

technical field

[0001] The invention relates to the field of thermal insulation and in particular to the thermal insulation of enclosures or of heat transport or production systems.

[0002] Without being limited to this, the invention finds particular application in industrial processes implemented in the nuclear industry. Technological background

[0003] Thermal insulation of a physical system consists of reducing the exchanges or heat transfers between the inside and outside of that physical system.

[0004] For example, the physical system could be an enclosed space, piping, equipment, or devices.

[0005] Three types of heat transfer or exchange can be distinguished: Conduction, due to the progressive diffusion of thermal agitation in matter; convection, heat transfer which accompanies macroscopic movements of matter; radiation, which corresponds to the propagation of photons.

[0006] Generally, the three types of transfers coexist, however, depending on the thermodynamic conditions of the system, the respective proportions of the three types of transfers may vary.

[0007] In order to reduce heat exchange between the inside and outside of the physical system, it is common to equip the physical system to be insulated with one or more thermal insulation devices designed according to the desired reduction in heat exchange, the type(s) of heat transfer to be limited as a priority, the geometry of the system to be insulated and other constraints specific to the system to be insulated or its environment.

[0008] As an example, US-B-6391469 describes a multilayer thermal or sound insulation, or shielding panel made of layers of corrugated metal sheets, with an interposition of a flat sheet between each pair of corrugated sheets, for reflective thermal insulation in high-temperature applications.

[0009] As an example, KR 101 613 504 B1 describes an insulating device made of metallic material which is installed on the outer circumference of all kinds of pipes installed in a nuclear power plant, etc.

[0010] As an example, US 6,391,469 B1 describes multilayer metal foil panels for thermal or acoustic insulation or shielding comprising two or more layers of corrugated metal foil or metal sheet in which a layer of flat metal foil or metal sheet is positioned between each pair of corrugated layers.

[0011] As an example, US 5 068 218 A describes a honeycomb metallic catalyst having a roughly cylindrical metallic catalyst support body formed by spirally and alternately winding a first layer of sheet metal with a large wave pitch and a second layer of sheet metal with a small wave pitch stacked in such a way as to form a large number of honeycomb gas flow ducts.

[0012] As an example, FR 2 321 346 A1 describes a process for producing parts through which channels pass. Summary

[0013] The idea behind the invention aims to provide an effective insulation device against the three types of heat transfer.

[0014] Furthermore, another idea underlying the invention is to limit the risk of damage to the physical system to be isolated.

[0015] According to one embodiment, the invention provides a thermal insulation device comprising: a metal enclosure, and several metal sheets stacked successively in a thickness direction of the metal enclosure, the metal sheets comprising: ∘ metal sheets with reliefs; ∘ support metal sheets arranged between the metal sheets with reliefs; Each embossed metal sheet has a plurality of first reliefs, each with a first height along the thickness direction. These first reliefs are supported by a metal sheet adjacent to the embossed metal sheet. Each embossed metal sheet has a plurality of second reliefs, each with a second height along the thickness direction; the first height being greater than the second height.

[0016] Thanks to these characteristics, the thermal insulation device makes it possible to limit the three different types of heat transfer (conduction, convection and radiation).

[0017] The first plurality of reliefs on a textured metal sheet helps to limit contact with adjacent support metal sheets within the enclosure.

[0018] In doing so, the initial plurality of landforms helps to limit the transfer of thermal energy by conduction. Thermal transfer by conduction is further limited when the cross-section of the initial landforms is small.

[0019] The second plurality of reliefs of a metal sheet with reliefs allows to limit the movement of air within a space between a metal sheet with reliefs and an adjacent metal sheet of support.

[0020] In doing so, the second plurality of reliefs helps to limit the transfer of thermal energy by convection within the spaces containing air between the metal sheets with reliefs and the metal support sheets.

[0021] Finally, the metallic material(s) of the metal sheets give the metal sheets high reflectivity, particularly in the infrared range.

[0022] In doing so, the metal sheets help to limit the transfer of thermal energy by radiation.

[0023] A thickness direction of the enclosure is a direction normal to a wall of the enclosure.

[0024] The height of the reliefs is measured in a direction normal to an average surface of each embossed metal sheet.

[0025] The height of the reliefs considered is the distance from crest to crest, or from summit to summit, between two reliefs of the same type (first or second) located on either side of a metal sheet with relief.

[0026] Furthermore, apart from its metallic components, the device contains only air or another ambient gas. The device does not contain fiberglass or any other solid material that could damage the system being insulated in the event of an incident.

[0027] Depending on the embodiment, such a thermal insulation device may include one or more of the following characteristics.

[0028] In one embodiment, the plurality of first reliefs protrudes from the two faces of said embossed metal sheet. Thus, a gap corresponding to the height of the first reliefs is maintained between the embossed metal sheet and two supporting metal sheets arranged on either side of the embossed metal sheet.

[0029] In one embodiment, the plurality of secondary reliefs protrudes from both faces of the embossed metal sheet. Convection can be slowed by the secondary reliefs on either side of the embossed metal sheet, thereby limiting heat transfer by convection.

[0030] According to one embodiment, the plurality of first reliefs is located on the surface of the metal sheet with reliefs according to a first periodic spatial arrangement.

[0031] Thus, the contact points between two consecutive metal sheets are regularly distributed, which promotes uniform thermal insulation performance.

[0032] According to one embodiment, the plurality of second reliefs is located on the surface of the metal sheet with reliefs according to a second periodic spatial arrangement.

[0033] Thus, the reliefs that slow down airflow are regularly distributed within the layer of air contained between two metal sheets, which promotes uniform thermal insulation performance.

[0034] According to one embodiment, the plurality of first reliefs forms protuberances distributed on the surface of the metal sheet with reliefs according to a periodic spatial arrangement defined according to a first and a second spatial period; the first spatial period being defined in a first direction of a mean plane of the surface of the metal sheet with reliefs; and the second spatial period being defined in a second direction of the mean plane.

[0035] Thus, the contact between two consecutive metal sheets occurs at localized protrusions, which can be quite small, meaning they have a small cross-section. Unlike a corrugation, such a protrusion does not extend continuously along a line. This minimizes heat transfer by conduction between two consecutive metal sheets.

[0036] The first and second directions are preferably perpendicular. However, it is possible that the first and second directions may intersect rather than be perpendicular.

[0037] According to one embodiment, the plurality of second reliefs forms protuberances distributed on the surface of the metal sheet with reliefs according to a periodic spatial arrangement defined according to a third and a fourth spatial period; the third spatial period being defined in the first direction of the mean plane of the surface of the metal sheet with reliefs; and the fourth spatial period being defined in the second direction of the mean plane.

[0038] Preferably, the difference between the first height and the second height is greater than or equal to 4 mm.

[0039] In one embodiment, the first height is greater than 6 mm and less than 30 mm. For example, the first height can be between 7 and 20 mm, or even between 12 and 16.5 mm. In other words, the peak-to-peak distance between the first two raised areas located on either side of a textured metal sheet is greater than 6 mm and less than 30 mm. It can be between 7 and 20 mm, or even between 12 and 16.5 mm.

[0040] The initial thickness determines the spacing between successive metal sheets and qualitatively reduces heat transfer by conduction and radiation as the initial thickness increases. However, the amount of air trapped between two metal sheets also increases as the initial thickness increases, which could promote convective heat transfer. A thickness range of 6 mm to 30 mm provides a good compromise for reducing overall heat transfer between two consecutive metal sheets.

[0041] According to one embodiment, the second height is between 3 and 15 mm. Similarly, the second height corresponds to the distance from peak to peak, or from apex to apex, between two second reliefs located on either side of a metal sheet with reliefs.

[0042] Thus, the airflows generated by the temperature gradient between two consecutive metal sheets are slowed down, which helps to limit the heat transfer by convection between two consecutive metal sheets.

[0043] In one embodiment, the metal support sheet is either a flat metal sheet or an embossed metal sheet. In the latter case, the embossed metal sheet may have an embossing obtained by stamping.

[0044] For example, this embossing can be achieved by pressing two forming dies from a press machine against a flat metal sheet.

[0045] Thanks to the embossing, the backing sheet also helps to limit heat transfer by convection between two consecutive metal sheets.

[0046] The embossed metal sheet thus comprises a single plurality of reliefs on its surface. Furthermore, the height of the embossings obtained by stamping is less than 5 mm.

[0047] According to one embodiment, the embossed metal sheet is made of stainless steel.

[0048] Thus, embossed metal sheets exhibit excellent long-term stability, can be cold-worked, and possess a high coefficient of reflectivity for thermal radiation.

[0049] According to one embodiment, the metal support sheet is made of stainless steel.

[0050] Thus, the metal support sheets exhibit excellent long-term stability, can be cold-worked, and possess a high coefficient of reflectivity for thermal radiation.

[0051] In one embodiment, the metal enclosure is also made of stainless steel. Similarly, the metal enclosure exhibits excellent long-term stability and can be cold-worked while possessing a high thermal radiation reflectivity.

[0052] According to one embodiment, the thickness of the embossed metal sheet is between 0.01 and 0.10 millimeters, for example 0.05 mm. According to another embodiment, the thickness of the supporting metal sheet is between 0.01 and 0.10 millimeters, for example 0.05 mm.

[0053] Thus, a high number of consecutive metal sheets can be used without excessively increasing the weight of the insulation device, to finely segment the interior space of the enclosure and thus minimize thermal convection.

[0054] According to a particular embodiment, the thickness of the enclosure walls is between 0.4 and 0.8 mm

[0055] According to one embodiment, the metal enclosure comprises one or more perforated flanges of varying thickness.

[0056] These flanges correspond to the portions or walls of the enclosure that must be in contact with other adjacent insulation devices, as opposed to the portions or walls of the enclosure facing outwards or towards the physical system to be insulated. The thickness of the flanges is therefore less than that of the other portions of the enclosure, which helps to limit thermal bridging caused by these walls connecting the portions of the enclosure facing outwards to the portions facing the physical system to be insulated. For example, the thickness of each flange is 0.1 mm.

[0057] In one embodiment, the textured metal sheets are welded to at least one wall of the metal enclosure. Preferably, one or each of the textured metal sheets is spot-welded to the metal enclosure. The spot welding can be carried out around the entire circumference of the metal sheet or, conversely, only on certain portions of the circumference, for example, the portions corresponding to two opposite faces of the metal enclosure.

[0058] In one embodiment, the metal support sheets are welded to at least one wall of the metal enclosure. Preferably, one or each of the metal support sheets is tack-welded to the metal enclosure. The tack welding can be carried out around the entire circumference of the metal sheet or, conversely, only on certain portions of the circumference, for example, the portions corresponding to two opposite faces of the metal enclosure.

[0059] According to one embodiment, the device comprises 5 to 30 metal sheets, preferably between 10 and 20 metal sheets.

[0060] The number of metal sheets may depend on the desired thermal insulation performance.

[0061] It can also depend on the available space around the physical system to be insulated, or on the maximum weight the insulation device can bear. In one example, this maximum weight is 25 kg per insulation device.

[0062] Thus, these ranges make it possible to obtain a good compromise between thermal insulation performance, the dimensions and weight of the enclosure and the cost of the thermal device.

[0063] According to one embodiment, the thermal insulation device has a thickness along the thickness direction of the enclosure of between 30 and 250mm.

[0064] According to one embodiment, the invention also provides an installation for the production of energy comprising at least one nuclear reactor and a thermal insulation device of the aforementioned type arranged to isolate a component of the nuclear reactor, for example a steam pipe or a tank.

[0065] According to one embodiment, the invention provides a method for manufacturing a thermal insulation device, the method comprising: to form a plurality of relief metal sheets, each of said relief metal sheets comprising a plurality of first reliefs and a plurality of second reliefs on its surface and being obtained by pressing two forming dies against a flat metal sheet, the forming dies comprising a plurality of first studs and a plurality of second studs, a height of the first studs being greater than a height of the second studs; the height of the first studs determining the height of the first reliefs; and the height of the second studs determining the height of the second reliefs so that a height of the first reliefs is greater than a height of the second reliefs;within a metal enclosure, successively stack, in one direction of the thickness of the metal enclosure, the embossed metal sheets and a plurality of support metal sheets so that the support metal sheets are arranged between the embossed metal sheets.

[0066] The height of the pins is measured relative to the plane of the matrix under consideration.

[0067] According to one embodiment, the first studs are distributed within the forming dies according to a first periodic spatial arrangement so that the first reliefs are located on the surface of the metal sheet with reliefs according to this first periodic spatial arrangement.

[0068] Thus, the first reliefs of the formed metal sheet with reliefs are distributed within it according to periodic spatial arrangements determined by the periodic arrangements of the first pins.

[0069] According to one embodiment, the second studs are distributed within the forming dies according to a second periodic spatial arrangement so that the second reliefs are located on the surface of the metal sheet with reliefs according to this second periodic spatial arrangement.

[0070] Thus, the second reliefs of the formed metal sheet with reliefs are distributed within it according to periodic spatial arrangements determined by the periodic arrangements of the second studs. Brief description of the figures

[0071] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings. [ Fig.1 ] There figure 1represents a cross-sectional view of the metal sheets of a straight thermal insulation device. Fig. 2 ] There figure 2 is a cross-sectional view of the metal sheets of a curved thermal insulation device. Fig.3 ] There figure 3 illustrates a curved thermal insulation device, capable of insulating a pipe from a piping system. Fig. 4 ] There figure 4 It also illustrates a curved thermal insulation device, capable of insulating a pipe from a piping system. Fig. 5 ] There figure 5 illustrates a press machine comprising a lower forming die and an upper forming die, each comprising the pins. Fig. 6 ] There figure 6 illustrates a first forming matrix comprising pins distributed according to a first example of a periodic arrangement. Fig. 7 ] There figure 7 illustrates a second forming matrix comprising pins distributed according to a second example of periodic arrangement. Fig. 8] There figure 8 illustrates a metal sheet with reliefs comprising a plurality of first reliefs and a plurality of second reliefs. Fig. 9 ] There figure 9 illustrates a manufacturing step of a thermal insulation device according to a first example of its implementation: the stacking of a textured metal sheet within the enclosure of a thermal insulation device. The pluralities of first and second textures are distributed according to a first example of periodic arrangement. Fig. 10 ] There Figure 10 illustrates another manufacturing step of the thermal device according to the first example: the stacking of a metal support sheet within the enclosure of the thermal insulation device. Fig. 11 ] There figure 11also illustrates the stacking of a metal sheet within the enclosure of a thermal insulation device according to a second embodiment. The pluralities of first and second reliefs are distributed according to a second example of periodic arrangement. Fig. 12 ] There figure 12 also illustrates the stacking of a metal support sheet within the enclosure of a thermal insulation device according to the second embodiment. Fig. 13 ] There figure 13 illustrates an enclosure to be insulated, comprising several thermal insulation devices. Fig. 13 ] There figure 14 illustrates a section of piping comprising several pipes to be insulated, including several thermal insulation devices. Description of the implementation methods

[0072] THE figures 3 and 4 illustrate a 100 curve thermal insulation device according to an example of implementation.

[0073] The device comprises a metal enclosure 20 inside which are stacked embossed metal sheets 1 and support metal sheets 2 (not visible to the figures 3 and 4 ). The metal sheets 1 and 2 are fixed, for example by welding, to the internal walls of the metal enclosure 20.

[0074] The weld can be continuous or, on the contrary, only on some parts of the circumference of each metal sheet 1 or 2. According to one embodiment, the weld is a spot weld.

[0075] Any geometry – shape and dimensions – is possible for enclosure 20, depending on the geometry of the system it must isolate. figures 9 to 12 illustrate 20 enclosures with different shapes and dimensions, and different from the example of the realization of the figures 3 and 4 Furthermore, the Figures 13 and 14The physical systems to be insulated exhibit a variety of shapes, both straight and curved, and of varying dimensions. The enclosure 20 of the thermal insulation device(s) that may be used to equip such devices can therefore also be of various shapes and dimensions.

[0076] As illustrated in the figure 3 The enclosure 20 can include an enclosure body 20b and perforated flanges 20a. The enclosure body 20b is a semi-cylindrical shell with a central space 200. The central space 200 is adapted to receive a pipe to be thermally insulated.

[0077] The perforated flanges 20a correspond to portions of walls with a reduced thickness compared to the rest of the metal enclosure 20.

[0078] The enclosure 20 is made of metals or metal alloys. Therefore, the enclosure 20 benefits from the reflective properties of metals, which helps to reduce heat transfer by radiation.

[0079] According to one embodiment, the enclosure 20 is made of stainless steel, also called stainless steel or inox. Stainless steel or inox is a steel as defined by standard EN 10020 containing a minimum of 10.5% chromium and a maximum of 1.2% carbon according to this standard EN 10020.

[0080] Any type of stainless steel as defined by EN 10020 can be used to construct the enclosure 20. Stainless steels have poor thermal conductivity. Therefore, the enclosure 20 reduces heat transfer by conduction. Furthermore, most types of stainless steel are easy to cut, bend, deform, and weld, making the enclosure 20 easy to manufacture.

[0081] According to one example, enclosure 20 is made of 304 stainless steel.

[0082] In addition to the general advantages of stainless steels described above, 304 stainless steel can be cold-worked, exhibits excellent malleability, and has relatively low electrical and thermal conductivity for a metal: 16.2 W / m·K at 100 °C and 21.5 W / m·K at 500 °C. Enclosure 20 benefits from these physical properties, thus reducing heat transfer by conduction.

[0083] Furthermore, the thickness of the walls of the metal enclosure 20 is between 0.5 and 0.8 mm. When the enclosure has an enclosure body 20b and perforated flanges 20a, the latter have a thickness of 0.1 mm. This thickness helps to limit thermal bridging between the walls of the metal enclosure 20 in contact with the physical system to be insulated and the walls of the metal enclosure 20 in contact with the outside.

[0084] THE figures 1 and 2schematically illustrate the stacking of metal sheets 1 and 2 within enclosure 20. Metal sheets 1 and 2 are stacked one on top of the other in the thickness direction E of enclosure 20 (not shown in figures 1 and 2 ). The metal sheets 1 and 2 are fixed to the walls of the enclosure 20, for example by welding.

[0085] The stacking of metal sheets 1 and 2 can include as many sheets of metal 1 and 2 as necessary, depending on the desired insulation performance. In practice, the number of stacked metal sheets 1 and 2 may depend on the temperature of the physical system to be thermally insulated, the desired thermal insulation performance, and / or the geometry of the enclosure 20. The geometry of the enclosure 20 may itself depend on the available space in the environment of this system.

[0086] Thus, by way of illustration, six embossed metal sheets 1 (1a to 1f) and six support metal sheets 2 (2a to 2f), i.e. twelve metal sheets 1 and 2, are stacked one on top of the other at the figure 1 . To the figure 2 , four embossed metal sheets 1 and four support metal sheets 2, i.e. eight metal sheets 1 and 2, are stacked.

[0087] Metal sheets 1 and 2 are made of metals or metal alloys like enclosure 20. Similar to enclosure 20, metal sheets 1 and 2 benefit from the reflective properties of metals which helps to reduce heat transfer by radiation.

[0088] According to one embodiment, the metal sheets 1 and 2 are made of stainless steel, also called stainless steel or inox.

[0089] Similarly, any type of stainless steel as defined by EN 10020 can be used to produce metal sheets 1 and 2. Stainless steels have relatively poor thermal conductivity. Therefore, metal sheets 1 and 2 reduce heat transfer by conduction compared to other metals. Furthermore, most types of stainless steel are easy to cut, bend, form, and weld, which facilitates the production of metal sheets 1 and 2, as will be described in more detail below.

[0090] According to one example of implementation, metal sheets 1 and 2 are made of 304 stainless steel.

[0091] Similarly, in addition to the general advantages of stainless steels presented above, metal sheets 1 and 2 benefit from its physical properties and thus reduce heat transfer by conduction.

[0092] Furthermore, the metal sheets 1 and 2 have a thickness between 0.01 and 0.10 millimeters, for example 0.05 mm. Such a thickness allows the metal sheets 1 and 2 to be handled without breaking them, particularly during the forming of the relief multiples.

[0093] The embossed metal sheets 1 comprise on their surface a plurality of first reliefs 11 and a plurality of second reliefs 12 as illustrated in figures 1 and 2 .

[0094] For example, at the figure 1The metal sheet with reliefs 1a comprises a plurality of first reliefs 11 and a plurality of second reliefs 12. As illustrated, the plurality of first reliefs 11 has a height, along the thickness direction E, greater than the height of the plurality of second reliefs 12. In other words, the distance between two vertices of first reliefs 11 located on either side of a metal sheet is greater than the distance between two vertices of second reliefs 12 located on either side of this metal sheet.

[0095] According to one embodiment, the plurality of first reliefs 11 each have the same height. For example, the height of the first reliefs 11 is greater than 6 mm. This height corresponds to the distance from crest to crest, or from peak to peak, between two reliefs located on either side.

[0096] Furthermore, according to one embodiment, the metal sheet 1a has on its two faces a plurality of first reliefs 11, of the same height or not, as illustrated in figures 1 and 2 In other words, the plurality of first reliefs 11 protrudes from the two faces of the metal sheet with reliefs.

[0097] According to a preferred embodiment, the metal sheet 1a has on its two faces a plurality of first reliefs 11 of the same height greater than 6 mm, for example 12.5 mm or 16.5 mm. Thus, two crests of first reliefs 11 located on either side of the metal sheet 1a are separated by a distance greater than 6 mm, for example 12.5 mm or 16.5 mm.

[0098] Furthermore, according to one embodiment, the plurality of first reliefs 11 is located on the surface of the metal sheet with reliefs 1 according to a first periodic spatial arrangement.

[0099] For example, the plurality of first reliefs 11 forms protuberances distributed on the surface of the relief-bearing metal sheet 1a according to a periodic spatial arrangement defined by a first and a second spatial period. Thus, this spatial arrangement is not reducible to a cross-sectional view as represented in figures 1 and 2 .

[0100] The first spatial period is defined in one direction along the mean plane of the surface of the embossed metal sheet, and the second spatial period is defined in a second direction along the mean plane. These two spatial periods may be different from each other.

[0101] According to one embodiment, the two directions are orthogonal to each other.

[0102] For example, the two directions are orthogonal to each other and the first and / or second spatial period is between 150 and 300 mm, for example they are 240 mm.

[0103] Similarly, according to one embodiment, the plurality of secondary reliefs 12 have the same height. For example, the height of the secondary reliefs 12 is between 3 and 15 mm. Likewise, this height corresponds to the peak-to-peak distance, or apex-to-apex distance, between two reliefs 12 located on either side of a textured metal sheet.

[0104] Furthermore, according to one embodiment, the metal sheet 1a has on its two faces a plurality of secondary reliefs 12, of the same height or not, as illustrated in figures 1 and 2 In other words, the plurality of secondary reliefs 12 protrudes from the two faces of said metal sheet with reliefs 1.

[0105] According to a preferred embodiment, the metal sheet 1a has on its two faces a plurality of secondary reliefs 12 of the same height between 3 and 15 mm, for example 8 mm. Thus, two crests of secondary reliefs 12 located on either side of the metal sheet 1a are separated by a distance between 3 and 15 mm, for example 8 mm.

[0106] These methods of implementation can be combined with each other as illustrated in the figure 1 or 2 : the metal sheet with reliefs 1a has on its two faces a plurality of first reliefs 11 of the same height greater than 6 mm and a plurality of second reliefs 12 of the same height between 3 and 15 mm.

[0107] According to one embodiment, the gap between the first and second heights is between 4 and 10 mm.

[0108] Similarly, the plurality of secondary reliefs 12 forms protuberances distributed across the surface of the relief metal sheet according to a periodic spatial arrangement 1 defined by a third and fourth spatial period. Likewise, this spatial arrangement is not reducible to a cross-sectional view as represented in the figures 1 and 2 .

[0109] The third spatial period is defined in a third direction of the mean plane of the surface of the embossed metal sheet and the fourth spatial period is defined in a fourth direction of this mean plane.

[0110] The third and fourth spatial periods may be different from each other.

[0111] According to one embodiment, these third and fourth directions are orthogonal to each other.

[0112] For example, these two directions are orthogonal to each other and the first and / or second spatial period is between 50 and 200 mm, for example 80 mm.

[0113] The metal support sheets 2 are flat metal sheets or embossed metal sheets obtained by stamping (not shown).

[0114] To the figure 1 or 2 , the metal sheets 2 (2a to 2f) are flat metal sheets.

[0115] Embossed metal backing sheets feature a unique plurality of reliefs on their surface. Furthermore, the height of these reliefs is less than 5 mm. This height corresponds to the edge-to-edge distance between two embossments located on opposite sides of a metal backing sheet.

[0116] Within enclosure 20, the plurality of first reliefs 11 of each relief metal sheet 1 rests against a support metal sheet 2 adjacent to the relief metal sheet 1 as illustrated in figures 1 and 2 Thus, the plurality of first reliefs 11 makes it possible to limit the contact between the metal sheets 1 and 2. In doing so, the first reliefs 11 make it possible to limit the heat transfer by conduction between two consecutive metal sheets 1 and 2 within the stack.

[0117] For example, the first reliefs 11 of the metal sheet 1a are supported by the metal support sheet 2a.

[0118] Similarly, the first reliefs 11 of layer 1c are supported against the metal support sheet 2b and against the metal support sheet 2c.

[0119] In addition, the embossed metal sheets 1 and the support metal sheets 2 are fixed to the internal walls of the metal enclosure 20. For example, the entire periphery of each metal sheet is welded to the internal walls of the metal enclosure 20.

[0120] Thus, each pair of embossed metal sheet 1 and support metal sheet 2 - for example the pair (1c ;2c) form an air layer within the enclosure 20.

[0121] The stacking of metal sheets 1 and 2 therefore forms layers of air which limit heat exchange by conduction since air is a thermal insulator.

[0122] Furthermore, the second reliefs 12, lower in height than the first reliefs 11, help to limit the movement of the air contained in each layer formed by a metal sheet with reliefs 1, a support sheet 2 and the walls of the enclosure 20. Thus, the second reliefs 12 help to limit the heat transfer by convection. Manufacturing process

[0123] We will now describe the steps in a manufacturing process for a thermal insulation device.

[0124] The first step consists of forming a metal sheet with reliefs 1 comprising a plurality of first reliefs 11 and a plurality of second reliefs 12 on its surface such as those described previously, by pressing two forming dies 30a and 30b of a press machine against a flat metal sheet.

[0125] There figure 5illustrates a press machine 30 comprising an upper forming die 30a and a lower forming die 30b.

[0126] Each matrix 30a and 30b comprises a plurality of first picots 31 and a plurality of second picots 32.

[0127] These two pressing dies allow the formation of a relief metal sheet 1 by pressing the two dies against a flat metal sheet to be formed.

[0128] The height of the first pins 31 then determines the height of the first reliefs 11 of the metal sheet with reliefs 1 formed. Similarly, the height of the second pins 32 determines the height of the second reliefs 12 of the metal sheet with reliefs 1 formed.

[0129] The first 31 spikes have a height between 60 and 68 mm and the second 32 spikes have a height between 50 and 60 mm.

[0130] The height of the pins 31 and 32 is measured relative to the plane of the pressing dies 30a and 30b.

[0131] Thus, by simultaneously pressing the flat metal sheet to be formed, the dies 30a and 30b form on the surface of the metal sheet a plurality of first reliefs 11 and a plurality of second reliefs 12. In other words, the flat metal sheet to be formed is sandwiched by the two forming dies 30a and 30b.

[0132] The movement distance of the dies (their stroke) and the heights of the pins 31 and 32 determine the heights of the first and second reliefs 11 and 12, respectively. The metal sheet with reliefs 1 then comprises a plurality of first reliefs 11 and a plurality of second reliefs 12 with a height less than the height of the first reliefs 11. In particular, the height of the first and second reliefs is determined by the end-of-stroke position of the two dies. This end-of-stroke position can be controlled by a programmable logic controller (PLC). More precisely, the height of the first reliefs is equal to the length of the mutual overlap between the first pins 31 of die 30a and the first pins 31 of die 30b at the end-of-stroke position of the two dies.Similarly, the height of the second reliefs is equal to the length of the mutual overlap between the second pins 32 of matrix 30a and the second pins 32 of matrix 30b in the end position of the two matrices, this overlap length being necessarily less since the second pins 32 are shorter than the first pins 31. More precisely, the difference between the two overlap lengths, therefore the difference between the heights of the two reliefs, is twice the difference in length between the second pin 32 and the first pin 31.

[0133] Furthermore, according to one embodiment, the first pins 31 are distributed within the forming dies 30a and 30b according to a first periodic spatial arrangement so that the first reliefs 11 are located on the surface of the metal sheet with reliefs 1 according to this first periodic spatial arrangement.

[0134] This first periodic spatial arrangement is defined by two spatial periods, each extending in a direction that is not collinear with each other. These two directions may be orthogonal to each other.

[0135] Similarly, according to one embodiment, the second pins 32 are distributed within the forming dies 30a and 30b according to a second periodic spatial arrangement so that the second reliefs 12 are located on the surface of the metal sheet with reliefs 1 according to this second periodic spatial arrangement.

[0136] Similarly, this second periodic spatial arrangement is defined according to two spatial periods, each extending in a direction that is not collinear with each other. These two directions may be orthogonal to each other.

[0137] THE figures 6 And 7illustrate a particular combination of these two modes of realization: the periodic arrangements are each defined according to two spatial periods and these two spatial periods have directions orthogonal to each other.

[0138] According to one embodiment, the flat metal sheet to be formed is made of stainless steel, which allows it to be worked cold as explained previously.

[0139] There figure 8 schematically illustrates a relief metal sheet 1 formed by pressing dies 30a and 30b against a flat metal sheet.

[0140] The metal sheet with relief 1 has on its surface first reliefs 11 and second reliefs 12 according to the periodic spatial arrangements of the pins 31 and 32 of the forming dies 30a and 30b.

[0141] The visible face of the metal sheet 1 allows us to distinguish the reliefs 11 and 12 forming bumps from the pins 31 and 32 of the lower matrix 30a and the reliefs 11 and 12 forming hollows from the pins 31 and 32 of the upper matrix 30b.

[0142] The second step consists of forming a plurality of embossed metal sheets 1 by repeating the previous step. A plurality of embossed sheets 1 can thus be formed from a plurality of flat metal sheets to be formed and the forming dies 30a and 30b.

[0143] Finally, the last step consists of stacking successively in a direction of thickness of the metal enclosure 20, the metal sheets with reliefs 1 formed and a plurality of metal sheets of support 2 so that the metal sheets of support 2 are arranged between the metal sheets with reliefs 1.

[0144] Any means of fastening can then be used to fix the metal sheets to the walls of enclosure 20. For example, it is possible to weld the metal sheets to the walls of enclosure 20.

[0145] Depending on the thermal insulation performance, a determined number of metal sheets 1 and 2 are stacked within the enclosure 20.

[0146] The metal support sheets 2 can be flat or embossed following a stamping process.

[0147] In one embodiment, the embossing of the metal backing sheets 2 is performed by the dies of the press machine, which are equipped with a plurality of pins of a single height. Generally, the stroke of the dies for embossing is shorter than that required for creating the first reliefs 11 and the second reliefs 12.

[0148] THE figures 9 And 11illustrate the stacking of a relief metal sheet 1a within an enclosure 20 according to two different embodiments: the dimensions and geometry of the enclosure 20 are not the same, the dimensions and shape of the relief metal sheets 1 are also different.

[0149] The embossed metal sheet 1a is fixed to the internal walls of the metal enclosure 20 by spot welding portions of its periphery to the internal walls of the metal enclosure 20. The weld line 61a indicates the location of this weld.

[0150] To the figure 9 , traces 63 of the future weld lines are identified, on the walls of the metal enclosure 20.

[0151] THE Figures 10 And 12 do they illustrate the stacking of a 2nd layer of metal support sheet within the enclosures 20 respectively illustrated in figures 9 And 11: here too, the support sheets 2 are not of the same dimensions or shape.

[0152] Similarly, a 62nd weld line is visible at Figures 10 And 12 . Examples

[0153] We will now describe two different examples of the thermal insulation device 100.

[0154] In the first example, the thermal device 100 has a cylindrical enclosure 20, for example analogous to Figures 9 and 10 , made from F17 / 304 stainless steel alloy.

[0155] Its dimensions are as follows: Inner diameter = 3604mm Outer diameter = 4083mm Thickness of enclosure 20 of device 100 = 240mm Height of enclosure 20 of device 100 = 693mm

[0156] The embossed metal sheets 1 include first embossments 11 with a height of 16.5 mm and second embossments 12 with a height of 10 mm obtained with the following press machine parameters: The first forming die 30a and the second forming die are square in shape with a length of 1000 mm.

[0157] The first forming die 30a comprises nine first pins 31 with heights of 61.5 mm, 64.5 mm, and 66.5 mm. They are distributed within the die according to a square periodic pattern with sides of 240 mm, forming four squares with sides of 240 mm. In rows, they measure 66.5 mm, 64.5 mm, and 61.5 mm. In other words, the first pins 31 are distributed within the first forming die according to a spatial arrangement with two spatial periods of 240 mm extending along two orthogonal directions.

[0158] The second set of 32 pins is 60 mm high and is distributed within the forming die according to a square periodic pattern with sides of 80 mm. In other words, the second set of 32 pins is distributed within the first forming die according to a spatial arrangement with two 80 mm spatial periods extending along two orthogonal directions. There are 112 second set of 32 pins.

[0159] The second forming die comprises 16 first pins distributed 31 according to the same periodic square pattern of 240 mm on each side, and 105 second pins distributed 32 according to the same periodic square pattern of 80 mm on each side.

[0160] The first 16 pins 31 form four lines of respective heights of 66.5 mm, 64.5 mm, 63 mm and 61.5 mm and the second pins 32 have a height of 60 mm.

[0161] The insulation device according to the first example was subjected to a thermal insulation performance test under the following conditions: Ambient temperature = 40°C Heating temperature = 325°C Device 100 in horizontal position

[0162] All the heights shown are defined with respect to the surface of each matrix.

[0163] The metal support sheets 2 used are embossed metal sheets.

[0164] The results are as follows: Heat flux measured at the center of the external wall of device 100: 4.77 x 10⁻² W / (mK) Average heat flux: 6.4 x 10⁻² W / (mK)

[0165] In the second example, the thermal device 100 is equipped with a generally cylindrical enclosure 20, for example analogous to the figure 3 , made from F17 / 304 stainless steel alloy.

[0166] The dimensions are as follows: Inner diameter = 3604mm Outer diameter = 4083mm Thickness of enclosure 20 of device 100 = 240mm Height of enclosure 20 of device 100 = 693mm

[0167] The embossed metal sheets 1 include first embossments 11 with a height of 12.5 mm and second embossments 12 with a height of 7.5 mm obtained with the following press machine parameters: The same press machine used is the same.

[0168] The first forming die comprises 16 first pins distributed 31 according to a square periodic pattern of 240 mm on each side, and 105 second pins distributed 32 according to a square periodic pattern of 80 mm on each side.

[0169] The first 31 studs are 65 mm and 63 mm high. Only the first row of studs is 65 mm high. The second 32 studs are 60 mm high.

[0170] The second forming die has nine initial 31 pins with heights of 65 mm and 63 mm. They are distributed within the die according to a periodic square pattern with sides of 240 mm, forming four squares of 240 mm sides. In rows of three, they measure 65 mm, 63 mm, and 63 mm. In other words, the first 31 pins are distributed within the first forming die according to a spatial arrangement with two spatial periods of 240 mm extending along two orthogonal directions.

[0171] The initial conditions for the thermal insulation performance test were as follows: Ambient temperature = 40°C Heating temperature = 323°C Device 100 in horizontal position

[0172] All the heights shown are defined with respect to the surface of each matrix.

[0173] The metal support sheets 2 used are embossed metal sheets.

[0174] The results are as follows: Heat flux measured at the center of the external wall of device 100: 6.36 x 10⁻² W / (m / K) Average heat flux: 8.54 x 10⁻² W / (m / K) Use

[0175] THE Figures 13 and 14 illustrate physical systems to be isolated of different shapes and dimensions.

[0176] Devices 100 can be used to isolate such physical systems.

[0177] For example, the figure 13 Figure 100 illustrates an enclosure to be insulated, equipped with thermal insulation devices. The enclosure is a cylinder closed by a hemispherical shell. Each insulation device covers a portion of the surface corresponding to an angular sector around the axis of symmetry of the cylinder. The insulation devices have the same radius of curvature as the covered portion of the cylinder.

[0178] For example, the figure 14illustrates a plurality of pipes forming part of a piping section. Such piping may be installed in a power generation facility, including at least one nuclear reactor. In such facilities, the temperatures generated can be very high. Thus, the piping in such facilities is then equipped with several thermal insulation devices 100 having a right-handed, semi-cylindrical shape, as illustrated in figures 3 or 4 , or straight quarter-cylinders. Others

[0179] The use of the verb "comporter", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0180] In claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

1. Thermal insulation device (100) comprising: - a metal enclosure (20), and, - several metal sheets (1; 2) stacked successively in a direction of thickness (E) of the metal enclosure (20), the metal sheets comprising: - metal sheets with raised elements (1); - supporting metal sheets (2) disposed between the metal sheets with raised elements; each metal sheet with raised elements (1) having a plurality of first raised elements (11) having a first height along the direction of thickness (E), the first raised elements (11) bearing against a supporting metal sheet (2) adjacent to the metal sheet with raised elements (1), characterized in that each metal sheet with raised elements (1) has a plurality of second raised elements (12) having a second height along the direction of thickness (E); the first height being greater than the second height.

2. Thermal insulation device (100) according to the preceding claim, wherein the plurality of first raised elements (11) projects with respect to the two faces of said metal sheet with raised elements (1) and the plurality of second raised elements (12) projects with respect to the two faces of said metal sheet with raised elements (1).

3. Thermal insulation device (100) according to any one of the preceding claims, wherein the plurality of first raised elements (11) is localised on the surface of the metal sheet with raised elements (1) according to a first periodic spatial arrangement; and / or the plurality of second raised elements (12) is localised on the surface of the metal sheet with raised elements (1) according to a second periodic spatial arrangement.

4. Thermal insulation device (100) according to the preceding claim, wherein the plurality of first raised elements (11) forms protuberances distributed on the surface of the metal sheet with raised elements according to a periodic spatial arrangement defined according to a first and a second spatial period; the first spatial period being defined in a first direction of an average plane of the surface of the metal sheet with raised elements; and the second spatial period being defined in a second direction of the average plane; and / or the plurality of second raised elements (12) forms protuberances distributed on the surface of the metal sheet with raised elements according to a periodic spatial arrangement defined according to a third and a fourth spatial period; the third spatial period being defined in the first direction of the average plane of the surface of the metal sheet with raised elements; and the fourth spatial period being defined in the second direction of the average plane.

5. Thermal insulation device (100) according to any one of the preceding claims, wherein the first height is greater than 6mm and less than 30mm.

6. Thermal insulation device (100) according to any one of the preceding claims, wherein the second height is between 3 and 15mm.

7. Thermal insulation device (100) according to any one of the preceding claims, wherein the supporting metal sheet (2) is a flat metal sheet or an embossed metal sheet.

8. Thermal insulation device (100) according to any one of the preceding claims, wherein the metal enclosure (20), the metal sheet with raised elements (1) and / or the supporting metal sheet (2) is made of stainless steel.

9. Thermal insulation device (100) according to any one of the preceding claims, wherein a thickness of the metal sheet with raised elements (1) and / or the supporting metal sheet (2) is between 0.01 and 0.10 millimetres.

10. Thermal insulation device (100) according to any one of the preceding claims, wherein the metal sheets with raised elements (1) are welded to at least one wall of the metal enclosure (20); and / or the supporting metal sheets (2) are welded to at least one wall of the metal enclosure (20).

11. Thermal insulation device (100) according to any one of the preceding claims comprising 5 to 30 metal sheets (1; 2), preferably between 10 and 20 metal sheets.

12. Thermal insulation device (100) according to any one of the preceding claims having a thickness along the direction of thickness of the enclosure (20) of between 30 and 250mm.

13. Installation intended for energy production, comprising at least one nuclear reactor and one thermal insulation device according to any one of the preceding claims arranged to insulate a component of the nuclear reactor.

14. Method for manufacturing a thermal insulation device (100), the method comprising: forming a plurality of metal sheets with raised elements (1), each of said metal sheets with raised elements comprising a plurality of first raised elements (11) and a plurality of second raised elements (12) on its surface and being obtained by pressing two forming dies (30a; 30b) against a flat metal sheet, the forming dies (30a; 30b) comprising a plurality of first pins (31) and a plurality of second pins (32), a height of the first pins (31) being greater than a height of the second pins (32); the height of the first pins (31) determining the height of the first raised elements (11); and the height of the second pins (32) determining the height of the second raised elements (12), such that a height of the first raised elements (11) is greater than a height of the second raised elements; within a metal enclosure (20), stacking successively in a direction of thickness of the metal enclosure (20), the metal sheets with raised elements (1) and a plurality of supporting metal sheets (2), such that the supporting metal sheets (2) is disposed between the metal sheets with raised elements (1).

15. Manufacturing method according to the preceding claim, wherein the first pins (31) are distributed within forming dies (30a; 30b) according to a first periodic spatial arrangement, such that the first raised elements (11) are localised on the surface of the metal sheet with raised elements (1) according to this first periodic spatial arrangement; and / or the second pins (32) are distributed within forming dies (30a; 30b) according to a second periodic spatial arrangement, such that the second raised elements (12) are localised on the surface of the metal sheet with raised elements (1) according to this second periodic spatial arrangement.