Method for restoring a sealed chamber

Abstract

The present invention relates to a method for restoring a sealed chamber (10) intended to be subjected to a specific pressure range higher than atmospheric pressure, comprising a first casing (12) and a second casing (14) which are intended to be mounted so as to bear against one another in a joint plane (P1). The method involves producing at least one groove (38) in at least one of the bearing surfaces (20, 22) of the joint plane (P1), along a contour to be sealed (Ce), the depth of the groove (38) varying along the contour to be sealed (Ce) according to certain measurements.

Description

[0001] DESCRIPTION

[0002] TITLE: METHOD FOR RESTORING AN ENCLOSURE TO ITS CONDITION

[0003] WATERPROOF

[0004] Technical field of the invention

[0005] The present invention relates to a method for restoring a sealed enclosure.

[0006] The invention relates more particularly to a method of restoring a sealed enclosure belonging, for example, to a machine operating under pressure, as well as a sealed enclosure obtained by this method.

[0007] Technical background

[0008] A pressurized machine consists of various components which, once assembled, must be leak-proof. Pressurized machines can be subjected to high temperatures and high pressures.

[0009] The interfaces between the assembled parts that make up the pressure vessel require special attention to ensure sealing under all operating conditions. In many applications, these interfaces require a specific sealing technique.

[0010] In the case of a sealed enclosure that is part of the machine, the enclosure comprises a first box and a second box mounted against each other along a joint plane that forms an interface. This joint plane includes a first bearing surface belonging to the first box and a second bearing surface belonging to the second box.

[0011] Regardless of the sealing technique used, the geometry and correct condition of the bearing surfaces are essential for achieving a good seal. However, due to aging, the geometry and condition of the surfaces deteriorate, potentially resulting in a loss of sealing.

[0012] The degradation of the geometry can be due to deformation of the components, for example by creep, mechanical stress, or fatigue. It can also be due to deterioration of the interface surface, for example by oxidation, erosion, corrosion, or washout.

[0013] To address the degradation of the geometry of the joint plane's bearing surfaces, one can replace the components, in this case the enclosures, or leave the enclosure as is, accepting the loss of airtightness. However, these solutions are unsatisfactory because they are costly and / or negatively impact the performance of the machine the enclosure houses.

[0014] Another solution to remedy this deterioration is to repair the bearing surfaces. This solution generally involves welding. For example, in the specific case of a steam turbine, the gaps between the upper and lower turbine casings can be filled by welding additional material, such as stainless steel, onto the bearing surface of the lower turbine casing. However, this work is time-consuming, and the additional material must be machined and treated after welding to obtain a flat, watertight area that matches the bearing surface of the upper casing.

[0015] Furthermore, the bearing surface of the upper body can be significantly deformed, making it very difficult to weld it to the welded area of ​​the lower body. Additionally, at room temperature, it may be possible to align the bearing surfaces of the upper and lower bodies, but under heat (when the turbine is running), further deformation can occur, leading to the two halves of the housing opening again. Therefore, this welding solution is not entirely satisfactory.

[0016] Previous art

[0017] EP 2 959 195 B1 describes a method for creating a circular seal to restore a watertight seal between two opposing surfaces that have undergone deformations rendering them non-planar. Measurements of the gap between the surfaces are taken at multiple locations, and the seal is characterized by a thickness that varies along its circumference but is uniform at each angular position. No groove is formed in the surfaces, and this method uses a specially manufactured irregular seal, which is expensive.

[0018] FR 3 057 333 A1 relates to the sealed joint of two gas turbine casings, which are susceptible to significant thermal deformation or deformation caused by internal pressure. The seal is ensured by a C-shaped gasket. This gasket is housed in grooves that pre-exist the machine was commissioned and whose depths are uniform, unlike the invention. The possibility of irregular and permanent surface deformations is not addressed.

[0019] Prior art therefore does not indicate, nor does it suggest, the repair of a sealed enclosure by inserting a commercially available, regularly shaped seal of a cross-section well suited to maintaining the seal, even in the presence of highly irregular deformations of the surfaces to be sealed.

[0020] Summary of the invention

[0021] The invention aims to solve the aforementioned problems by proposing a method for restoring a sealed enclosure designed to be subjected to a specific pressure range exceeding atmospheric pressure, said enclosure having already undergone at least one operating cycle including pressurization, said enclosure comprising a first box and a second box designed to be mounted against each other along a joint plane, said joint plane comprising a first bearing surface and a second bearing surface, as well as a contour to be sealed, said at least one operating cycle having led to deterioration of at least one bearing surface of the joint plane, the method being characterized in that it comprises the following steps: E1) Opening the enclosure by separating the first box from the second box, E2) Measuring the flatness defects of the joint plane on the two bearing surfaces,at least in the vicinity of the contour to be sealed, E3) Creation of at least one groove in at least one of the bearing surfaces, along the contour to be sealed, the depth of the groove varying along the contour to be sealed according to the measurements carried out in step E2, E4) Insertion of at least one sealing element into the groove, E5) Closure of the enclosure by fixing the first box onto the second box, so as to compress the sealing element between the first box and the second box.

[0022] According to other features of the invention:

[0023] - the measurement of flatness defects in step E2 includes a sub-step E21 during which the thickness of the deformation of each bearing surface is measured along the contour to be sealed, relative to an undeformed joint plane, and, during step E3, the depth of the groove along the contour to be sealed is determined as a function of the maximum thickness of the deformation measured in sub-step E21;

[0024] - step E2 includes a sub-step E22 during which the depth of the groove along the contour to be sealed is determined according to the deformation measurements carried out in the first sub-step E21;

[0025] - step E2 includes a sub-step E22 during which the depth of the groove along the contour to be sealed is determined according to the compression forces expected at different points of the sealing element;

[0026] - the sealing element is made of a stainless metal alloy, for example a nickel-based alloy where nickel represents at least 50% by mass;

[0027] - the sealing element has a C or W cross-section;

[0028] - the sealing element is equipped with an elastic return element which stresses the sealing element in the direction of a support against the two opposite support surfaces;

[0029] - the first support surface belongs to the first box and the second support surface belongs to the second box.

[0030] The invention also proposes an enclosure intended to be subjected to a specified pressure range above atmospheric pressure, said enclosure comprising a first box and a second box intended to be mounted against each other along a joint plane, said joint plane comprising a first bearing surface and a second bearing surface, as well as a contour to be sealed, comprising at least one groove in at least one of the bearing surfaces, along the contour to be sealed, the depth of the groove varying along the contour to be sealed as a function of the deformation of the joint plane relative to an undeformed joint plane, and at least one sealing element which is inserted in the groove and which is compressed between the first box and the second box.

[0031] According to other advantageous features of the enclosure:

[0032] - the sealing element is made of a stainless metal alloy, for example a nickel-based alloy where nickel represents at least 50% by mass;

[0033] - the sealing element has a C or W cross-section;

[0034] - the sealing element is equipped with an elastic return element which stresses the sealing element in the direction of a support against the two opposite support surfaces;

[0035] - the first support surface belongs to the first box and the second support surface belongs to the second box;

[0036] - a sum of the total depth of at least one groove and a spacing of the bearing surfaces is constant for each location along the contour to be sealed.

[0037] The invention also proposes a machine characterized in that it comprises an enclosure according to one of the characteristics mentioned above.

[0038] Brief description of the figures

[0039] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the attached drawings in which:

[0040] [Fig.1] is an exploded perspective view that schematically represents a sealed enclosure equipped with a first and a second chamber in the open state;

[0041] [Fig.2] is an enlarged view of part of the bearing surface of the second box, or lower box, visible in figure 1, which schematically represents a main opening of an intake duct opening into the bearing surface and communicating with an intake chamber through an intake orifice when the joint plane at the level of the bearing surface is perfectly flat;

[0042] [Fig.3] is a view similar to that of figure 2 which schematically represents a deformed area of ​​the bearing surface of the second caisson in the vicinity of the main opening;

[0043] [Fig.4] is a view similar to that of figure 3 which schematically represents a groove made along a contour to be sealed of the bearing surface of the second box in the vicinity of the main opening and which illustrates a third step of a process of restoring the sealed enclosure;

[0044] [Fig.5] is a view similar to that of figure 4 which schematically represents a sealing element before its insertion into the groove of the bearing surface of the second box and which illustrates a fourth step in the repair process;

[0045] [Fig.6] is a view similar to that of figure 5 which schematically represents the sealing element after insertion into the groove and which illustrates the fourth step of the reconditioning process;

[0046] [Fig.7] is an axial section view which schematically represents the joint plane between the two boxes when it is not deformed;

[0047] [Fig.8] is a view similar to that of figure 7 which schematically represents the joint plane after deformation of the bearing surfaces of the two boxes for example following aging of the parts;

[0048] [Fig.9] is a view similar to that of figure 8 which schematically represents the joint plane after implementation of an embodiment of the process according to the invention comprising the making of the groove in the two bearing surfaces and the insertion of the sealing joint element;

[0049] [Fig.10] is a block diagram that schematically represents the restoration process according to the invention.

[0050] Detailed description of the invention

[0051] For the description of the invention and the understanding of the claims, the vertical, longitudinal and transverse orientations according to the V, L, T frame indicated in the figures, whose longitudinal L and transverse T axes extend in a horizontal plane, will be adopted without limitation and without limiting reference to terrestrial gravity.

[0052] In the description that follows, identical, similar or analogous elements will be designated by the same reference numbers.

[0053] Figure 1 shows an example of a sealed enclosure 10 designed to be subjected, in operation, to a specified pressure range greater than atmospheric pressure.

[0054] The enclosure 10 shown here is, for example, a pressure vessel that can contain steam, gas, or liquid. It might be, for instance, a vessel belonging to a compressor, turbine, pump, or component used in chemical processing. This type of enclosure 10 can be used, for example, in a power plant, an oil refinery, or other types of installations.

[0055] According to the embodiment shown, the enclosure 10 comprises a first box 12, forming here an upper half-body, and a second box 14, forming here a lower half-body.

[0056] In the following description, a vertical orientation along the direction V shown in Figure 1 will be used, but not limited to that shown. Of course, the enclosure 10 could be oriented in any direction other than that shown here.

[0057] The two boxes 12, 14 are fixed against each other by means of a first flange 16, or upper flange, and a second flange 18, or lower flange.

[0058] Each flange 16, 18 is presented here in the form of a transverse rim, with respect to the vertical direction V, forming a first bearing surface 20 and a second bearing surface 22 belonging respectively to the first box 12 and the second box 14. The first bearing surface 20 and the second bearing surface 22 together form a joint plane P1 at the interface between the two boxes 12, 14.

[0059] According to an alternative embodiment (not shown), the flanges 16, 18 could belong to frames surrounding and holding the boxes 12, 14 together. Ideally, the joint plane P1 is perfectly flat and transverse. It will be referred to in the remainder of this description as the undeformed joint plane P1a.

[0060] The first box 12 and the second box 14 are fixed to each other by a fixing system, for example by means of screws 21 and associated nuts 23 which are mounted in through holes 25 positioned along the flanges 16, 18 and visible in figure 2.

[0061] The second box 14 is here equipped with an inlet pipe 24, which opens into the second support surface 22 through a main opening 26, visible in more detail in figure 2. The inlet pipe 24 is used here to supply the enclosure 10 with pressurized fluid, for example steam, gas, or a liquid.

[0062] The first box 12 is here fitted with an exhaust pipe 28 which opens here into the main wall 30 of the first box 12.

[0063] In the enlarged view of Figure 2, an inlet orifice 32, or inlet nozzle, is schematically represented, which connects the inlet pipe 24 to an inlet chamber 34 in such a way that the fluid arriving under pressure in the inlet pipe 24 is forced to flow towards the inlet chamber 34 through the inlet orifice 32. The inlet orifice 32 is shown here in the form of a straight groove 33 formed in the second bearing surface 22 and connecting the main opening 26 to the inlet chamber 34.

[0064] Once admitted into the inlet chamber 34, the fluid is generally forced to flow through a nozzle (not shown) into a secondary chamber 36. The passage of the fluid through the inlet orifice 32 allows for the conversion of pressure / temperature energy into kinetic energy, or vice versa. It is important that the order in which the fluid passes—first into the inlet chamber 34, then into the secondary chamber 36—is respected for the system equipping enclosure 10 to function correctly and with maximum efficiency.

[0065] Figure 2 shows that the second bearing surface 22 of the undeformed joint plane P1a is perfectly flat, without any damage due to operation or aging. The area of ​​the second bearing surface 22 located around the main opening 26 is a key area for establishing the seal of the connection between the inlet pipe 24 and the inlet chamber 34. In this description, the area surrounding the main opening 26, along its edge, will be designated as the sealing contour Ce.

[0066] Figure 3 schematically represents the same second bearing surface 22 as that of Figure 2 after a certain number of operating cycles of the enclosure 10 which caused wear / deformation in a deformed area Z1 of the joint plane P1.

[0067] This deformed zone Z1 is represented here in the form of inclined planes which extend from the main opening 26, on either side of the inlet orifice 32, down towards the inlet chamber 34 and the two secondary chambers 36 adjacent to the inlet chamber 34.

[0068] Of course, this representation of the deformed zone Z1 does not correspond to an actual form of deformation as observed on real parts. It is a schematic illustration intended to facilitate understanding of the invention. In reality, the deformed zone Z1 generally has a more organic, non-planar shape, for example, as a wavy or irregular surface.

[0069] It is noted that the deformed zone Z1 creates auxiliary fluid passages between the main opening 26 and the secondary chambers 36, and even towards the inlet chamber 34, without passing through the inlet orifice 32. The existence of these auxiliary fluid passages causes a deterioration of the sealing of the enclosure 10, which results in performance losses of the enclosure 10 and the installation it equips.

[0070] A method for restoring enclosure 10, in accordance with the teachings of the invention, is now described. This method aims to repair enclosure 10 by reducing or eliminating the harmful effects of the deformation of the joint plane P1.

[0071] The repair process is implemented on enclosure 10 shown in Figure 3, that is, after enclosure 10 has undergone deformation of the joint plane P1, for example, following a large number of operating cycles. The process is schematically represented in Figure 10.

[0072] The process includes a first dismantling step E1 during which the enclosure 10 is opened so as to separate the first box 12 from the second box 14. The fixing system which holds the first box 12 against the second box 14 is therefore dismantled, here the screws 21 and the nuts 23 are removed from the flanges 16, 18.

[0073] Dismantling enclosure 10 allows us to expose the bearing surfaces 20, 22 which form the joint plane P1.

[0074] During a second diagnostic step E2, the flatness defects of the joint plane P1 are measured by analyzing the flatness of the two bearing surfaces 20, 22, at least in the vicinity of the contour to be sealed Ce.

[0075] Advantageously, the second step E2 includes a first substep E21 in which the deformation thickness of each bearing surface 20, 22 is measured along the contour to be sealed Ce, relative to the undeformed joint plane P1a. This deformation thickness can be measured, for example, at a determined distance from the main opening 26, possibly over a strip of determined width. During this first substep E21, the thickness measurements allow the positive and negative height variations to be determined along the contour to be sealed Ce.

[0076] In a third step E3, a groove 38 of non-constant depth is formed in each bearing surface 20, 22, along the contour to be sealed Ce, as illustrated in Figure 4. The depth of the groove 38 corresponds here to the depth relative to the deformed surface. The depth of the groove 38 is adjusted along the contour to be sealed Ce according to the thickness measurements taken during the second step E2. The depth of the groove 38 must be adapted to receive a sealing element 40 suitable for ensuring continuous watertight contact between the two bearing surfaces 20, 22, along the contour to be sealed Ce, as illustrated in Figures 5 and 6.

[0077] According to an alternative embodiment (not shown), the groove 38 can be formed in a single bearing surface 20 or 22. Advantageously, the depth of the groove 38 is determined based on a second substep E22 in which the deformation thickness measurements along the contour to be sealed Ce for each bearing surface 20, 22 are compiled so as to define, at each point of the contour to be sealed, the depth of the groove 38 that allows for the formation of a bearing surface with sufficient vertical height for the sealing element 40. The depth of the groove 38 may depend, in particular, on the compressive forces expected at different points of the sealing element 40.

[0078] We now describe an example of a procedure for determining the depth of the groove 38 in each bearing surface 20, 22.

[0079] The compression C(i) of the sealing element 40 must cover at least the minimum compression Cmin and the maximum deformation Defmax(i) of the sealing plane P1 at each point, or location (i), of the contour to be sealed Ce. This requirement can be determined by the following formula, at a given point, or location (i), of the contour to be sealed Ce:

[0080] [Equation 1]

[0081] C(i) = Cmin + Defmax(i)

[0082] Or :

[0083] C(i) represents the compression of the sealing element 40 at location (i),

[0084] Cmin represents the minimum compression that the sealing element 40 needs to function as a seal, which may depend on the choice of the sealing element 40, the pressure range and the temperature range of the fluid (liquid, gas) operating in the enclosure 10, Defmax(i) represents the maximum deformation at location (i), i.e. the maximum separation between the bearing surfaces 20 and 22 at this location.

[0085] Furthermore, the compression C(i) of the sealing element 40 at location (i) is also determined by the following formula:

[0086] [Equation 2] C(i) = Hjoint - Pthroat(i)

[0087] Or :

[0088] Hjoint represents the height of the sealing element 40 in its free state, Pgorge(i) represents the depth of the groove 38 at location (i). The groove 38 is either a single groove formed in one of the bearing surfaces 20 and 22, or composed of two opposing grooves formed respectively in each of these surfaces.

[0089] Thus, from formula [Equation 2], it is possible to calculate the depth of the groove at location (i):

[0090] [Equation 3]

[0091] Pgorge(i) = Hjoint - C(i).

[0092] Thus, by combining [Equation 1] and [Equation 2], we can determine the depth of the throat Pgorge at location (i) according to the following formula:

[0093] [Equation 4]

[0094] Pthroat(i) = Hjoint - Cmin - Defmax(i)

[0095] The depth Pgorge(i) of the throat 38 locally at location (i) is therefore a function of the maximum local deformation.

[0096] As a general rule, to prevent the sealing element 40 from coming out of its housing, i.e. the groove 38, it is preferable that the depth Pgroove of the groove 38 at location (i) be greater than half the height of the sealing element 40, which can be expressed by the following criterion:

[0097] [Equation 5]

[0098] Pgorge(i) > Hjoint / 2

[0099] This means that the height Hjoint of the sealing element 40 must be chosen according to the maximum deformation Defmax. However, the rule in equation 5 is not mandatory.

[0100] According to an embodiment proposed by the inventors for a housing 10 in a high-pressure turbine, it is envisaged to implement a seal in accordance with the teachings of the invention along the entire perimeter of the high-pressure turbine. It is therefore proposed to produce a sealing element 40, 16 meters long (divided into two parts).

[0101] The total deformation is between 0 and 1.1 mm. The sealing element 40 has a C-shaped cross-section with a height of 11 mm. The minimum compression Cmin of the sealing element 40 is 2.2 mm.

[0102] Using [Equation 4], we obtain a groove depth 38 between 8.8 mm and 7.7 mm. These values ​​comply with the safety criterion of [Equation 5] since 7.7 mm > 5.5 mm.

[0103] During a fourth step E4, the sealing element 40 is inserted into the groove 38, for example into the second bearing surface 22, as illustrated by figures 5 and 6.

[0104] During a fifth step E5, the enclosure 10 is closed by placing the first box 12 on the second box 14 and fixing them with screws 21 and nuts 23. The closing of the enclosure 10 causes compression of the sealing element 40 between the first box 12 and the second box 14.

[0105] Preferably, the sealing element 40 is made of a stainless metal alloy, for example, a nickel-based alloy such as Inconel®, offered by Special Metals Corporation. In this type of alloy, nickel constitutes at least half the material by mass. It may be alloyed with chromium and iron. This type of alloy is particularly suitable for use in turbines where the temperature may exceed 300°C and the pressure may exceed 60 bar.

[0106] The sealing element 40 can be provided with an outer coating of lower hardness than the stainless metal alloy forming the main part of the sealing element 40 in order to compensate for the roughness of the associated bearing surface on the opposite box 12, 14, if this is necessary to ensure optimal sealing of the contact between the parts.

[0107] The sealing element 40 has for example a C or W section (bilobed in the shape of an "epsilon" as shown in Figure 5, each of the superimposed lobes being compressed by a respective bearing surface 20 or 22).

[0108] The sealing element 40 can be provided with an elastic return element 42 which stresses the sealing element 40 in the direction of a support against the two opposite bearing surfaces 20, 22.

[0109] The sealing element 40 is custom-made, according to the contour to be sealed Ce and the characteristics of the bearing surfaces 20, 22. The sealing element can take complex shapes to follow the contour to be sealed Ce.

[0110] The sealing element 40 can change shape to compensate for changes in geometry of the bearing surfaces 20, 22, so as to compensate for both deformations due to aging and deformations related to transient operating conditions of the enclosure 10.

[0111] Advantageously, in the absence of pressure in the enclosure 10, the sealing element 40 is loaded by the elastic return element 42 so as to maintain sufficient contact pressure with the opposite bearing surface, in the grooves 38.

[0112] In the presence of pressure in the enclosure 10, the sealing element 40 is activated by the pressure in the enclosure 10 by changing shape and maintaining sufficient surface contact pressure.

[0113] The sealing element 40 is housed in the groove 38, which is formed in one or both of the bearing surfaces 20, 22, as previously indicated. Varying the depth of this groove 38 allows for sufficient contact pressure to be obtained for the application in question. The depth of the groove 38 is the variable that compensates for deformation due to aging of the various components of the enclosure 10.

[0114] The variable depth of the groove 38 is defined by mapping the deformation of the enclosure 10 at its bearing surfaces 20, 22, which creates a new reference plane to obtain correct compression of the sealing element 40. Figures 7 to 9 schematically represent a part of the enclosure 10 to illustrate the different configurations of the sealing plane P1 and the implementation of the repair process according to the invention.

[0115] Figure 7 shows the undeformed joint plane P1a, i.e. with perfectly flat bearing surfaces 20, 22, which allows a perfectly watertight contact between the two bearing surfaces 20, 22.

[0116] Figure 8 shows the joint plane P1 after deformation. It can be seen that each of the bearing surfaces 20 and 22 has an irregular corrugated profile, a consequence of aging due to multiple operating cycles, under the effect of the high pressures and temperatures to which the enclosure 10 was subjected.

[0117] Figure 9 shows the profile of the bottom of the groove 38 formed in each bearing surface 20, 22 in dotted lines, and the deformed profile of the bearing surfaces 20, 22 before the groove 38 was formed in solid lines. The sealing element 40 is received in the grooves 38, between the first box 12 and the second box 14.

[0118] It can be seen here that the groove, or each groove 38, has a depth that varies along the contour to be sealed, so as to adapt to the initial deformations undergone by the bearing surfaces 20, 22 and to allow the sealing element 40 to compensate for these deformations once the enclosure 10 is closed. However, it is advantageous for the bottoms of the grooves 38 to be at similar or nearly similar intervals for each location (i), so that the sealing element 40 undergoes uniform compression along its length. In other words, it is advantageous that ^Pgorge(i) + Defmax(i) = Constant [Equation 6], in which Pgorge (i) denotes the sum of the depths of the grooves 38 at location (i) if a groove is provided in each of the bearing surfaces 20 and 22. The same criterion applies if a groove 38 is provided in only one of the bearing surfaces, by replacing ^Pgorge(i) with Pgorge(i).

[0119] The enclosure 10 described and shown here is schematic and aims to illustrate the operation of the invention. Of course, the invention applies to other types of sealed enclosures with different configurations. According to various embodiments, the contour to be sealed Ce may have a different shape from that of the main opening 26 shown here, such as a circular, polygonal, or closed shape. The contour to be sealed Ce is located along said shape, where it is important to ensure a good seal.

[0120] LEGEND

[0121] 10: pregnant

[0122] 12: first box

[0123] 14: second box

[0124] 16: first bridle

[0125] 18: second bridle

[0126] 20: first support surface

[0127] 21: screw

[0128] 22: second support surface

[0129] 23: nut

[0130] 24: Intake duct

[0131] 25: through hole

[0132] 26: Main opening

[0133] 28: Exhaust pipe

[0134] 30: Main wall of the first caisson

[0135] 32: intake port

[0136] 33: groove

[0137] 34: Admission room

[0138] 36: secondary room

[0139] 38: throat

[0140] 40: sealing gasket element

[0141] 42: elastic return element

[0142] This: contour to be sealed

[0143] P1: Joint plane

[0144] P1 a: undeformed joint plane

[0145] Z1: deformed zone

Claims

DEMANDS 1. Method for restoring a sealed enclosure (10) intended to be subjected to a specified pressure range exceeding atmospheric pressure, said enclosure (10) having already undergone at least one operating cycle including pressurization, said enclosure (10) comprising a first casing (12) and a second casing (14) intended to be mounted against each other along a joint plane (P1), said joint plane (P1) comprising a first bearing surface (20) and a second bearing surface (22), as well as a contour to be sealed (Ce), said at least one operating cycle having led to deterioration of at least one bearing surface (20, 22) of the joint plane (P1), the method being characterized in that it comprises the following steps: E1) Opening of the enclosure (10) by separating the first box (12) from the second box (14), E2) Measurement of flatness defects of the joint plane (P1) on the two bearing surfaces (20, 22), at least in the vicinity of the contour to be sealed (Ce), E3) Forming at least one groove (38) in at least one of the bearing surfaces (20, 22), along the contour to be sealed (Ce), the depth of the groove (38) varying along the contour to be sealed (Ce) according to the measurements carried out in step E2, E4) Insertion of at least one sealing element (40) into the groove (38), E5) Closing the enclosure (10) by fixing the first box (12) onto the second box (14), so as to compress the sealing element (40) between the first box (12) and the second box (14).

2. A method according to the preceding claim, characterized in that the measurement of flatness defects in step E2 comprises a substep E21 in which the thickness of the deformation of each bearing surface (20, 22) is measured along the contour. to seal (Ce), with respect to an undeformed joint plane (P1 a), and in that, during step E3, the depth of the groove (38) along the contour to be sealed (Ce) is determined as a function of the maximum thickness of the deformation measured in substep E21.

3. Method according to claim 2, characterized in that step E2 comprises a substep E22 during which the depth of the groove (38) along the contour to be sealed (Ce) is determined as a function of the deformation measurements carried out in the first substep E21.

4. A method according to any one of the preceding claims, characterized in that step E2 comprises a substep E22 in which the depth of the groove (38) along the contour to be sealed (Ce) is determined as a function of the compression forces expected at different points of the sealing element (40).

5. A method according to any one of the preceding claims, characterized in that the sealing element (40) is made of a stainless metal alloy, for example a nickel-based alloy where nickel represents at least 50% by mass.

6. A method according to any one of the preceding claims, characterized in that the sealing element (40) has a C-shaped or W-shaped cross-section.

7. A method according to any one of the preceding claims, characterized in that the sealing element (40) is provided with an elastic return element (42) which stresses the sealing element (40) in the direction of a support against the two opposing bearing surfaces (20, 22).

8. A method according to any one of the preceding claims, characterized in that the first bearing surface (20) belongs to the first box (12) and the second bearing surface (22) belongs to the second box (14).

9. Enclosure (10) intended to be subjected to a specified pressure range exceeding atmospheric pressure, said enclosure (10) comprising a first chamber (12) and a second chamber (14) intended to be mounted in support against each other along a joint plane (P1), said joint plane (P1) comprising a first bearing surface (20) and a second bearing surface (22), as well as a contour to be sealed (Ce), the enclosure comprising at least one groove (38) in at least one of the bearing surfaces (20, 22) along the contour to be sealed (Ce), and at least one sealing element (40) which is inserted in the groove (38) and which is compressed between the first box (12) and the second box (14), characterized in that the depth of the groove (38) varies along the contour to be sealed (Ce) as a function of the deformation of the joint plane (P1) relative to an undeformed joint plane (P1a).

10. Enclosure (10) according to the preceding claim, characterized in that the sealing element (40) is made of a stainless metal alloy, for example a nickel-based alloy where nickel represents at least 50% by mass.

11. Enclosure (10) according to any one of claims 9 to 10, characterized in that the sealing element (40) has a C or W cross-section.

12. Enclosure (10) according to any one of claims 9 to 11, characterized in that the sealing element (40) is provided with an elastic return element (42) which stresses the sealing element (40) in the direction of a support against the two opposite bearing surfaces (20, 22).

13. Enclosure (10) according to any one of claims 9 to 12, characterized in that the first bearing surface (20) belongs to the first box (12) and the second bearing surface (22) belongs to the second box (14).

14. Enclosure according to any one of claims 9 to 13, characterized in that a sum of the total depth of at least one groove (38) and a spacing (Defmax) of the bearing surfaces (20, 22) is constant for each location (i) along the contour to be sealed (Ce).

15. Machine characterized in that it comprises an enclosure (10) according to any one of claims 9 to 14.

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