FR2983751A1 - CONSTRUCTION OF A SEALED MEMBRANE FROM METAL PLATES - Google Patents

Abstract

A construction apparatus (130) comprises a frame comprising an elongated member (140) adapted to be disposed along the overlapping marginal areas (14) of two metal plates (10) disposed on a support surface provided with anchoring (121), clamping means for engaging the frame with the anchoring members (121) so as to clamp at least one of the metal plates (10) against the support surface along the overlapping marginal areas ( 14, 15) of the first and second metal plates, and a support (60) movably mounted on said frame for carrying a welding tool (134) to the right of the overlapping marginal areas (14) of the two metal plates, the support mobile (60) being guided parallel to the elongated member (140).

Description

The invention relates to the field of sealed metal membranes constructed by welded joining of metal plates, especially in the field of metal membranes having corrugations to give the membrane flexibility and elongation capacity in one or more directions of a plane. .

Corrugated metal membranes are particularly used in the construction of sealed and thermally insulated vessels for the transport or storage of fluids whose temperature is significantly different from ambient air, in particular liquefied natural gas (LNG) stored at atmospheric pressure at approximately -162 ° C. FR-A-2238914 discloses an apparatus for the construction of such a metal membrane which comprises a rigid reinforcement, centering recesses adapted to fit at least partially on the corrugations of a metal panel and a fixing device for assembling temporarily the metal panel with the wall to cover.

According to one embodiment, the invention provides a method for constructing a waterproof membrane from metal plates, the method comprising: disposing a first metal plate on a support surface provided with anchoring members, the first metal plate comprising an elongate marginal area to be covered by a second metal plate, arranging the second metal plate on the support surface provided with the anchoring members, the second metal plate having an elongated marginal area arranged to cover the marginal area of the first metal plate, arrange a frame on at least the second metal plate, the frame comprising an elongate member disposed along the marginal areas overlapping the first and second metal plates, the elongated member having a plurality of complementary fasteners adapted to cooperate with each time with one of the anc organs raging of the support surface, anchoring the elongate member to the support surface by cooperation of the complementary fasteners with anchors of the support surface, engaging the frame with the anchoring members so as to tighten at least the second metal plate against the support surface along the overlapping marginal areas of the first and second metal plates, and performing a sealing line sealingly bonding the marginal areas overlapping the first and second metal plates with a mounted welding tool on a mobile support to the right of the marginal areas overlapping the two metal plates, the movable support being guided parallel to the elongate member of the frame. In some embodiments, this method may include one or more of the following features.

According to one embodiment, the frame is disposed on the first and second metal plates, the frame comprising two parallel spaced elongated members arranged along the marginal areas in overlap of the first and second metal plates on either side of the marginal zones in covering two metal plates, each elongate member having a plurality of complementary fasteners adapted to cooperate each time with one of the anchoring members of the support surface, and the two elongated members are anchored to the support surface by cooperation of complementary fasteners with anchoring members of the support surface located on either side of the marginal zones in overlap of the first and second metal plates.

According to one embodiment, the clamping of the first and second metal plates against the support surface is carried out with an elongated support beam connected to the frame and disposed on the marginal areas in overlap of the first and second metal plates. According to one embodiment, the metal plates are corrugated, a corrugated metal plate having in each case a series of projecting parallel corrugations which intersect the marginal zone of the plate and flat portions located between the corrugations, the elongated support beam having plane segments adapted to cooperate with planar portions of the first and second corrugated metal plates and curved portions adapted to circumvent the projecting corrugations.

According to one embodiment, the clamping of at least the second metal plate against the support surface is carried out with the corresponding elongate member of the frame. According to one embodiment, the metal plates are corrugated, a corrugated metal plate having in each case a series of projecting parallel corrugations which intersect the marginal area of the plate and flat portions between the corrugations, the elongate member of the frame each comprising planar segments able to cooperate with flat portions of the corrugated metal plate and curved portions able to bypass the projecting corrugations. According to one embodiment, the metal plates are corrugated, a corrugated metal plate having in each case a series of projecting parallel corrugations which extend parallel to the marginal zone of the plate and flat portions located between the corrugations, the or each elongate member of the frame being disposed on said planar portions. According to one embodiment, at least one elongate member of the frame is disposed between the marginal area of the corresponding plate and the closest parallel wave of said marginal area. According to one embodiment, the metal plates comprise bores, and the metal plates are arranged on the support surface so that the bores come to the right of the anchoring members, the cooperation of the complementary fasteners of the chassis with the components of the frame. anchoring being carried out through the holes of the metal plates. According to one embodiment, the invention also provides a construction apparatus for carrying out such a method, said apparatus comprising: a frame comprising an elongate member able to be disposed along the marginal zones 15 in overlap of two metal plates disposed on a support surface provided with anchoring members, the elongated member having a plurality of complementary fasteners adapted to cooperate each time with one of the anchoring members of the support surface for anchoring the frame to the a support surface, clamping means for engaging the frame with the anchoring members so as to clamp at least the second metal plate against the support surface along the marginal areas in overlap of the first and second metal plates, and a support movably mounted on said frame for carrying a welding tool to the right of the marginal areas overlapping the two plates metal, the movable support being guided parallel to the elongate member. According to embodiments, such apparatus may include one or more of the following features. According to one embodiment, the frame comprises two parallel spaced elongated members able to be arranged on either side of the marginal zones in overlap of the two metal plates, each elongate member comprising a plurality of complementary fasteners capable of cooperating with each one of the anchoring members of the support surface for anchoring the frame to the support surface, and the clamping means are adapted to engage the frame with the anchoring members so as to clamp the first and second metal plates against the support surface along marginal areas overlapping the first and second metal plates.

According to one embodiment, the clamping means are able to clamp the two elongate members of the frame against the metal plates at the anchoring members of the support surface. According to one embodiment, the apparatus further comprises a rigid gantry connected to the two elongated members of the frame and extending between the two elongated members so as to overlap the marginal areas in overlap of the two metal plates, the movable support being mounted on the portico. According to one embodiment, at least one of said elongated members comprises a guide rail for slidingly guiding the gantry along said at least one elongate member of the frame. According to one embodiment, the gantry comprises a guide rail parallel to the elongate members of the frame for slidably guiding the movable support relative to the gantry. According to one embodiment, the gantry comprises a second guide rail 15 for guiding the movable support transversely between the two elongated members of the frame. According to one embodiment, the apparatus further comprises a support beam arranged parallel to the elongate member or between the two elongated members of the frame and movably connected to the frame, the clamping means being able to exert a force away from the frame of the support surface against the anchoring member to cause pressure of the support beam towards the support surface by reaction. According to one embodiment, the support beam is connected to the frame by a lever pivotally mounted to an elongate member of the frame about an axis substantially parallel to the elongate member, the clamping means being arranged to pivot the lever compared to the chassis. According to one embodiment, the lever comprises an end portion extending on the other side of the frame relative to the support beam, the clamping means comprising a spacer element movably connected to the portion of the support. end of the lever and adapted to bear against the metal plate to exert a force tending to move the end portion of the lever from the support surface. According to one embodiment, a sealed casing is arranged on the surface of the bearing beam facing the support surface, the apparatus further comprising pressurizing means for generating fluid pressure within the casing waterproof. According to one embodiment, the pressurizing means are able to circulate a cooling liquid inside the sealed casing.

According to one embodiment, an elongate member of the frame each comprises a plurality of feet provided with complementary fasteners adapted to cooperate with the anchoring members. According to one embodiment, the complementary fastener comprises in each case a member selected from a nut intended to cooperate with a threaded rod of the support surface and a threaded rod intended to cooperate with a threaded bushing of the support surface. According to one embodiment, the complementary fastener comprises in each case a member chosen from a notched lug intended to cooperate with a wide-headed rod of the support surface and a wide-headed rod intended to cooperate with a brake lug. notch of the support surface. An idea underlying the invention is to facilitate the operations of blocking, docking and welding metal plates during the construction of a waterproof membrane. Some aspects of the invention start from the idea of blocking the displacements of the metal plates before and during the realization of a sealed seal at the overlap areas of the metal plates. Some aspects of the invention are based on the observation that the metallic material has a tendency to move locally under the effect of thermal expansion in the vicinity of the welding tool when producing a sealed weld line. between two plates. Certain aspects of the invention start from the idea of firmly fixing the zones of the plates adjacent to the weld zone to the wall, so as to limit or prevent these local displacements in order to improve the uniformity of the membrane and to limit the concentrations of constraints. Some aspects of the invention are based on the idea of blocking the movements of metal plates without resorting to too many pointing welds, which are generally long and difficult to achieve. The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent in the following description of several particular embodiments of the invention, given solely by way of illustration and not by way of example. limiting, with reference to the accompanying drawings. In these drawings: FIG. 1 is a sectional view of a sealed and insulating tank wall and of a clamping and welding apparatus according to a first embodiment mounted on this wall, along the line II of FIG. FIG. 2 is a view of the vessel wall and the clamping and welding apparatus of FIG. 1 along line II-II of FIG. 1; FIG. 3 is an enlarged detail view of FIG. zone III of FIG. 1. FIG. 4 is a partial perspective view of a sealed and insulating tank wall and of a clamping and welding apparatus according to a second embodiment mounted on this wall. FIG. 5 is an enlarged detail view of a frame of the machine of FIG. 4. FIG. 6 is a partial perspective view of a leaktight and insulating tank wall and of a clamping apparatus and FIG. welding according to a third embodiment mounted on this wall. FIG. 7 is an enlarged detail view of a frame of the machine of FIG. 6. FIG. 8 is a partial perspective view of a leaktight and insulating tank wall and of a clamping apparatus and FIG. soldering bare bar Tinte: Tue embodiment mounted on this wall. Referring to Figure 1, there is shown in section a sealed and thermally insulating wall structure suitable for producing an LNG transport or storage tank. The wall comprises several successive layers superimposed in the direction of the thickness on a supporting structure 1. The supporting structure 1 is for example the inner shell of the double hull of a ship. The wall structure comprises successively a secondary insulation barrier 2, a secondary sealing barrier 3, a primary insulation barrier 4 and a primary sealing barrier 5.

As best seen in FIG. 4, the primary sealing barrier 5 is here produced in the form of a corrugated metal membrane obtained by welded assembly of multiple rectangular metal plates 10. A metal plate 10 has, on its internal face, a first series of so-called low parallel corrugations 11 and a second series of so-called high parallel corrugations 12 whose respective directions are perpendicular.

The edges of the metal plate 10 are parallel to the corrugations 11 and 12. The terms "high" and "low" here have a relative meaning and mean that the first series of corrugations 11 has a height less than the second series of corrugations 12. At a junction 13 between a low ripple 11 and a high ripple 12, the low ripple is discontinuous, i.e. interrupted by a bend (not shown) which extends the vertex edge of the high corrugation 12 protruding above the vertex edge of the low corrugation 11. This form known otherwise is not visible in the figures. For example, the low corrugations 11 have a height defined between the crown edge and the surface of the metal plate 10 equal to about 36 mm and a width at the base of the corrugation 11 of the order of 53 mm. For example, the high corrugations 12 have a height defined between the apex edge and the surface of the plate 10 of the order of 54.5 mm and a width at the base of the corrugation 6 of about 77 mm. For example, the metal plate 10 is made of stainless steel sheet or aluminum and has a thickness of about 1.2 mm and can be shaped by folding or stamping. Other metals or alloys and other thicknesses are possible, knowing that a thickening of the metal plate 10 causes an increase in its cost and generally increases the rigidity of the corrugations. In the case of application of sealed membranes for cold liquid, a certain flexibility of the metal plate 10 is required to allow its thermal contraction without risk of rupture of the seal. For example, a metal plate 10 has three high undulations 12 distributed in its width and nine low undulations 11 distributed in its length. At one of the two lateral edges, and at one of the two longitudinal edges, the metal plate 10 has in each case a flat stamped strip 14, which is offset in the thickness direction with respect to the remainder of the plate 10 to cover the edge 15 of an adjacent metal plate 10. There are many possibilities for making the insulation barriers 2 and 4. In the example shown, the primary insulation barrier 4 which supports the primary sealing barrier 5 consists of polyurethane foam blocks 16 which comprise each time a cover panel 17 made of plywood. In use, the primary sealing barrier 5 rests on a substantially continuous flat surface formed by the cover panels 17 of the juxtaposed blocks 16. Processes and tools will now be described to construct this primary sealing barrier 5. This construction is carried out progressively, for example plate after plate or row of plates after row of plates, until completely covering the primary insulation barrier 4 The construction of the plane portions of the metal membrane will be described here. The realization of the angles of the tank is the subject of special provisions which have been described elsewhere, for example in EP-A-0573327.

The main steps carried out for the addition of a metal plate 10 to the metal membrane under construction are: position the metal plate 10 relative to the already assembled plates, so as to superpose the flat strips 14 on the corresponding edges of the plates already assembled and so as to align the corrugations of the metal plate 10 with the corrugations of the already assembled plates; anchoring the added metal plate to the support surface; - Set up a device for clamping and welding on the metal membrane, where a frame of the apparatus is disposed astride the already assembled membrane portion and the metal plate 10 added so as to span the flat strip 14 of the added metal plate 10, which is superimposed on the edge of the already assembled membrane portion; - make a sealed welding bead using this clamping and welding machine and remove the clamping and welding equipment; - Restoring the tightness of the metal plate 10 added if it was pierced to perform the above operations. The anchoring of the metal plate 10 to the support surface before the setting of the clamping and welding apparatus can be achieved in several ways. In one embodiment, steel strips 20 (see Figs 4 and 6) are provided in countersinks on the outer surface of the cover panels 17 at predetermined locations which correspond to the edges of the metal plates 10. Seams can then be made between the metal plate 10 and the steel strips 20 to anchor the metal plate 10 to the support surface. Such weld points must be made carefully: if it is too small, the weld spot can not ensure a solid anchorage; if it is too big, it may create a zone of weakness in the corrugated membrane. For example, these soldering points can be made at a periodic interval of 5 cm. In another embodiment (FIG 3), which can be combined with the previous one, there are provided anchoring members 21 fixed to the cover panels 17 and engaging in perforations 22 provided in the metal plate 10 at the locations correspondents. The anchoring of the metal plate 10 to the support surface can be carried out at these perforations, for example by producing weld points between the metal plate and the projecting anchoring members or by attaching the plate to the bodies of anchoring by any suitable means such as nut, rivet or other. Preferably in this case, these same anchoring members are used in the following step to temporarily anchor the clamping and welding apparatus on the metal diaphragm 5. With reference to FIGS. 1 to 3, a first embodiment will now be described. embodiment of the clamping and welding apparatus and its use.

The clamping and welding apparatus 30 comprises a rigid frame, made for example of aluminum to minimize its weight. This frame may consist of a structure of beams, for example beams with T-shaped section. This frame comprises an upper body 31 of elongated overall rectangular shape and two rows of support feet 32 fixed respectively along the two Longitudinal edges of the body 31. The feet 32 extend generally perpendicularly to the body 31. The upper body 31 carries a rectilinear guide rail 33 fixed longitudinally to the body 31 on the same side as the feet 32, between the two rows of feet 32. A welding torch 34 is attached to the guide rail 33 via a movable support 35. The movable support is mounted in a guided manner on the guide rail 33 so as to be able to follow a rectilinear path when carrying out the welding. The connection between the mobile support 35 and the rail 33 may be a simple slide. Optionally, a drive mechanism of the movable support 35 can also be provided, for example with a rack (not shown) attached to the guide rail 33 and an electric drive motor attached to the movable support 35 and meshing on the rack. The mobile support 35 also carries a pneumatic jack 38 extending perpendicularly to the body 31 and provided at its end with a support wheel 36 arranged to roll in the longitudinal direction of the guide rail 33. As can be seen in FIG. the apparatus 30 is mounted on the already assembled metal diaphragm 5 situated on the right of FIG. 1, and on the metal plate 10 to be added thereto, situated on the left of FIG. 1, so that the torch of welding 34 and the support roller 36 are in contact with the overlap zone between the strip 14 of the plate 10 and the corresponding edge of the adjacent plate. According to one embodiment, the lateral position of the support 35 between the two rows of legs 32 is fixed. According to another embodiment, this lateral position is adjustable by means of a guide not shown. For the anchoring of the device 30 to the tank wall, a cooperation is made between fasteners located at the end of the feet 32 and anchoring members 21 which are arranged on the cover panels 17 at regular intervals under the shape of several parallel rows spaced apart. Each metal plate 10 accommodates at least one row of anchoring members 21 at corresponding perforations 22. An example of the anchoring members and corresponding fasteners is best seen in FIG. 3. The anchoring member 21 comprises a flat base 24 housed in a counterbore 23 located on the face of the cover panel 17 which is connected to the foam block 16 and a rod 25 which extends through a through hole 26 formed in the panel 17 and which projects through the bore 22 of the metal plate 10 to end with an enlarged head 27. The corresponding attachment of the foot 32 has a flat tab 29 ending the foot 32 and extending parallel to the vessel wall on which the device is disposed and a notch 28 cut in the tab 29 to receive the rod 25. The section of the notch 28 is smaller than the section of the head 27, so that the tab 29 can not be engaged with or disengaged from the organ anchor 21 by means of a parallel displacement to the vessel wall. Preferably, the notch 28 is open on a side facing the longitudinal direction of the frame of the apparatus, so that all the feet 32 can be engaged with the corresponding anchoring members 21 by means of a single movement of longitudinal translation of the apparatus 30. For example, the apparatus 30 has 6 to 8 feet 32 in total. Once thus anchored to the tank wall, the device 30 can firmly lock the metal plate 10 and the edge of the membrane 5 to be welded to one another and achieve a very good docking for welding . For this, the device 30 comprises a support beam 40 which extends parallel to the two rows of feet 32 between them and whose shape is undulated to fit the contour of the membrane 5. In particular, Figure 2 shows the corrugations 41 of the beam 40 intended to match the corrugations 11 of the membrane 5 and the plane areas 42 of the beam 40 situated between the corrugations 41. As can be seen in FIG. 3, the support beam 40 is connected to a row of feet 32 by a set of levers 43 for engaging the beam 40 with the metal plate 10, in the overlap area with the adjacent plate. A lever 43 comprises a pivot axis 44 connected to the base of a foot 32 and oriented in the longitudinal direction of the frame, that is to say parallel to the support beam 40. The lever 43 extends globally in the transverse direction of the frame of the apparatus on either side of the foot 32. The inner end of the lever 43 has a bent portion 45 connected to the upper surface of the support beam 40 to exert pressure on the beam 40 substantially perpendicular to the support surface. The outer end 48 of the lever 43 comprises a clamping mechanism 46 consisting of an eccentric roller 47 pivotally connected to the lever 43 by an axis of rotation 49 and actuable by means of a pivoting lever 50 integral with the eccentric roller 47. 3, the eccentric roller 47 is shown in the gripping position, in which it exerts a thrust against the support surface formed by the vessel wall. This thrust has the effect of constraining the foot 32 against the head 27 of the anchoring member 21, which has the effect, by reaction, to constrain the support beam 40 against the metal membrane 5. In other In other words, the pivot axis 44 of the lever 43 makes it possible to transfer the thrust force of the eccentric roller 47 to the support beam 40 by preserving the moment of force. The respective length of the portions of the lever 43 located on either side of the pivot axis 44 makes it possible to produce a multiplying coefficient, which is greater than 1 in the example shown. As shown by the arrow 51, the lever 50 can be lowered to suppress the thrust of the eccentric roller 47 and thus disengage the apparatus 30 from the anchoring members 21. The lever mechanism shown in FIG. 3 can be reproduced along the frame at at least two of the legs 32, or at all the feet 32 of the row. The corresponding actuating levers 50 can be linked together to be actuated integrally. When the apparatus 30 is in the setting position as shown in FIG. 3, the pressure of the support beam 40 on the overlap area of the metal plates 10 to be welded together allows a blocking of the edges of the metal plates and a reliable docking along the entire length of the apparatus 30. A weld line can then be made between the edge of the strip 14 and the underlying plate by translating the movable support 35 along the rail 33. Simultaneously, the wheel 36 reinforces the docking of the plates by exerting pressure near the point of action of the welding torch 34. Thus, without it being necessary to carry out numerous preliminary welding points along the edge of the plate, a reliable weld line is achieved by the immobilization of the plates by the support beam 40, which notably avoids excessive sliding of the plate edge under the effect of temperature gradients. Preferably, the length of the apparatus 30 corresponds to the length of a single or a few metal plates 10. A plurality of apparatuses 30 may be arranged in alignment with one another to effect a weld on a larger wall area. extended. To avoid damaging the membrane 5, the support beam 40 preferably comprises a stress distribution pad 51 on its side facing the vessel wall. The pad 51 may be made of polytetrafluoroethylene (Teflon®) or other relatively flexible and heat-supporting material. In the example of FIG. 3, the pad 51 is made in the form of an inflatable hose of circular section fixed in a concave surface of the support beam 40. It is possible to circulate in the inflatable hose a fluid liquid or gaseous, especially a coolant to prevent the underlying vessel wall from being subjected to a temperature too high during the welding operation. To restore the tightness of the metal plates 10 at the perforations 22, a sealing plate 55 is welded to each of these perforations 22. According to one embodiment, this plate 55 is a washer integral with the rod 25 of the anchoring member 21, in the case where the anchoring member is intended to remain permanently in the tank. According to another embodiment, in which the anchoring member 21 is removable, the plate 55 completely closes the perforation 22 after removal of the rods 25. For example, a removable anchoring member may be made by providing a screw thread. the base of the rod 25 and a corresponding threaded hole in the base 24. With reference to Figures 4 and 5, will now be described a second embodiment of the clamping and welding apparatus and its use. Prior positioning and anchoring of plates can be performed as previously described. The elements that are identical or similar to those of the first embodiment bear the same reference number increased by 100. In FIGS. 4 and 5, the support surface of the metal membrane carries anchoring members made in the form of threaded studs. 121 arranged in rows parallel to the high corrugations 12 of the metal plates 10 at a row of studs 121 per row of plates 10. In FIG. 4, a metal plate 10 has in each case three high undulations 12 and a row of perforations (not shown) disposed between the second and the third high corrugation 12 to accommodate the studs 121. In Figure 5, the row of performances is disposed between the third high corrugation 12 and the offset strip 14 located at the plate edge. The clamping and welding apparatus 130 comprises two parallel main beams 140 which are each fixed to a row of studs 121 on either side of the overlap zone between the metal plates 10 to be welded together.

As best seen in FIG. 5, the beam 140 has an H-shaped section and has concave housings 141 in its bottom flange 58 to accommodate the low corrugations 11 of the metal plate 10. The studs 121 are engaged in corresponding bores of the lower flange 58 and nuts 146 are screwed onto the studs 121 to firmly tighten the beam 140 against the support surface, thus exerting pressure on the metal plate all along the overlap area between the plates 10, this which makes it possible to immobilize these. A mobile gantry 131 is mounted on the two beams 140 transversely thereto so as to span the overlap area of the plates 10. The gantry 131 5 comprises two feet 132 which are each slidably mounted on the upper flange 133 of the corresponding beam 140 by means of a slide 59. Again, a rack-and-pinion mechanism can be provided. The gantry 131 has a cross member 60 which connects the upper ends of the two legs 132 extending parallel to the vessel wall and carries a welding tool 134. Preferably, the welding tool 134 is slidably mounted. on the cross member 60 by means of a slide 61. Again, a rack-and-pinion mechanism can be provided. A support wheel may also be provided as before. The apparatus 130 is used as the apparatus 30 for immobilizing the metal plates and docking them during the welding operation. It is then removed from the membrane. The arrangement of FIG. 5 brings the beam 140 closer to the plate edge to improve the approaching action of the apparatus 130. The apparatus 230 shown in FIGS. 6 and 7 is similar to the apparatus 130. same reference numerals will be used to designate similar or identical elements. Thus, only the differences with the apparatus 130 are described. In the apparatus 230, the gantry 131 is fixed to the main beams 140. The gantry 131 is symmetrical, so that only one half has been shown in FIG. It comprises a rectangular frame 60 made of hollow tubes and mounted on four legs 132 whose base is each time fixed on one of the two beams 140. A guide rail 133 is fixed on the frame 60 at about half of its width. and extends parallel to the beams 140. The welding tool 134 is slidably mounted on the guide rail 133 by means of a slideway 59. In a variant, the transverse position of the guide rail 133 with respect to the frame 60 could be adjustable. As can be seen in FIG. 7, the main beams 140 are made of a thick sheet metal strip, for example approximately 10 mm, which is shaped to the profile of the corrugations of the metal plates 10 and which has bores not shown to accommodate the studs 121. This structure makes it possible to lighten the frame to facilitate the operations of laying, removing and transporting.

The apparatus 330 shown in FIG. 8 is similar to the apparatus 130. The same reference numerals will be used to designate similar or identical elements. Thus, only the differences with the apparatus 130 are described. In the case of the apparatus 330, the frame comprises only one main beam 140 which is put in place on the metal plate 10 to be welded to the part. of the primary watertight barrier 5 that is already installed. The clamping of the main beam 140 on the metal plate 10 serves to immobilize the metal plate 10 during the welding operation. The gantry 131 supporting the welding tool 134 is here made by means of two parallel arms cantilevered. An arm of the gantry 131 has a foot 132 whose base is linked by a slide to the upper flange 133 of the beam 140 and a half-cross 60 which extends from the top of the foot 132 towards the edge of the metal plate 10 and slightly beyond this edge to be able to support the welding tool 134 to the right of the overlap zone between the plates. The welding tool 134 is slidably mounted on the two parallel half-crosspieces 60 by means of slides 61 located on either side of the welding tool 134 with respect to the longitudinal direction of the beam 140. the only main beam 140, it is possible to sufficiently immobilize the two metal plates 10 overlap for the welding operation, because the beam 140 exerts a clamping on the top plate, which therefore exerts a clamping on the bottom plate at the level of the recovery zone. For this, it is preferable to bring the main beam 140 as close as possible to the welding zone. The arrangement of Figure 5 can be used for this. Stress distribution pads may also be provided under the bottom flange of the main beams 140 to distribute the pressure exerted on the metal membrane. Several types of fasteners have been described above for anchoring the clamping and welding apparatus to the vessel wall. Other embodiments are possible, in particular by inverting the male part and the female part in the abovementioned examples. For example, a threaded bush can be fixed in the cover panel 17 in accordance with the teaching of the application FR2887010. The technique described above for producing a waterproofing membrane can be used in various types of tanks, for example to form the primary waterproofing membrane of an LNG tank in a land installation or in a floating structure such as a ship LNG carrier or other.

The devices described above can easily be adapted to metal plates having other shapes, including flat sheets or plates whose corrugations project towards the tank wall. A better approach of the plates is obtained by adapting the profile of the support beam to the profile of the metal plate. The devices described above can be easily adapted to plates whose edges are circular or have other shapes. Although the invention has been described in connection with several particular embodiments, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they come within the scope of the invention. The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim. The use of the undefined article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps. In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim.

Claims (23)

REVENDICATIONS1. A method for constructing a waterproof membrane (5) from metal plates (10), the method comprising: disposing a first metal plate (10) on a support surface (17) provided with anchoring members (21, 121) ), the first metal plate having an elongate marginal area (15) to be covered by a second metal plate, arranging the second metal plate (10) on the support surface provided with the anchoring members, the second metal plate having a an elongate marginal area (14) arranged to cover the marginal area of the first metal plate, arranging a frame (31, 32, 40; 140) on at least the second metal plate, the frame comprising an elongated member (32; 140) disposed along the overlapping marginal areas (14, 15) of the first and second metal plates, the elongated member (32; 140) having a plurality of complementary fasteners (29, 146) adapted to s to cooperate each time with one of the anchoring members of the support surface, anchoring the elongate member to the support surface by cooperation of the complementary fasteners (29, 146) with anchoring members (21, 121) from the support surface, engaging the frame (31, 32, 40; 140) with the anchoring members (21, 121) so as to clamp at least the second metal plate (10) against the support surface (17) along the overlapping marginal areas of the first and second metal plates, and performing a weld line sealingly bonding the overlapping marginal areas (14, 15) of the first and second metal plates with a welding tool (34, 134) mounted on a movable support (35, 131, 134) in line with the marginal areas 25 overlapping the two metal plates, the movable support being guided parallel to the elongated member (32; 140) of the frame. The method of claim 1, wherein the frame (31, 32, 40; 140) is disposed on the first and second metal plates, the frame comprising two parallel spaced elongated members (32; 140) disposed along the marginal areas. in covering (14, 15) the first and second metal plates on either side of the marginal areas in overlap of two metal plates, each elongated member (32; 140) having a plurality of complementary fasteners (29, 146) adapted to cooperate each time with one of the anchoring members of the support surface, and wherein the two elongated members are anchored to the support surface by cooperation of the complementary fasteners (29, 146) with anchoring members (21 121) of the support surface on either side of the overlapping marginal areas (14, 15) of the first and second metal plates. A method according to claim 1 or 2, wherein the clamping of the first and second metal plates (10) against the support surface (17) is effected with an elongated support beam (40) connected to the frame and disposed on the overlapping marginal areas (14, 15) of the first and second metal plates. 4. The method of claim 3, wherein the metal plates are corrugated, a corrugated metal plate having in each case a series of parallel corrugations (11) which intersect the marginal area of the plate and flat portions between the corrugations. , the elongate bearing beam having planar segments (42) adapted to cooperate with planar portions of the first and second corrugated metal plates and curved portions (41) adapted to circumvent the projecting corrugations (11). The method of claim 1 or 2, wherein clamping at least the second metal plate (10) against the support surface (17) is performed with the corresponding elongate member (140) of the frame. 6. The method of claim 5, wherein the metal plates are corrugated, a corrugated metal plate having in each case a series of parallel corrugations (11) which intersect the marginal area of the plate and flat portions between the corrugations. , the elongate member of the frame having in each case flat segments adapted to cooperate with planar portions of the corrugated metal plate and curved portions (141) adapted to bypass the projecting corrugations. 7. The method of claim 5 or 6, wherein the metal plates are corrugated, a corrugated metal plate having in each case a series of parallel corrugations (12) which extend parallel to the marginal area of the plate and planar portions located between the corrugations, where each or each elongated frame member (32; 140) is disposed on said planar portions, and wherein the or each elongated frame member (32; 140) is disposed between the marginal area of the plate corresponding and the parallel wave (12) closest to said marginal area (14, Fig.5). 8. Method according to one of claims 1 to 7, wherein the metal plates comprise bores (22), and wherein the metal plates areposed on the support surface so that the bores (22) come to the right of the organs anchoring (21, 121), the cooperation of the complementary fasteners (29, 146) of the frame with the anchoring members (21, 121) being performed through the holes of the metal plates. 9. Construction apparatus for carrying out the method according to one of claims 1 to 8, said apparatus (30, 130) comprising: a frame (31, 32, 40; 140) comprising an elongated member (32; ) capable of being arranged along the overlapping marginal areas (14, 15) of two metal plates (10) arranged on a support surface (17) provided with anchoring members (21, 121), the elongated member comprising a plurality of complementary fasteners (29, 146) each engageable with one of the anchoring members (21, 121) of the support surface for anchoring the frame to the support surface, clamping means (46), 146) for engaging the frame with the anchoring members (21, 121) so as to clamp at least the second metal plate (10) against the support surface along the overlapping marginal areas (14, 15). ) of the first and second metal plates, and a support (35, 60, 134) movably mounted on the frame for carrying a welding tool (34, 134) to the right of the marginal areas overlapping the two metal plates, the movable support (35, 60, 134) being guided parallel to the elongate member (32, 140). An apparatus according to claim 9, wherein the frame (31, 32, 40; 140) comprises two parallel spaced elongated members (32; 140) adapted to be disposed on either side of the overlapping marginal areas (14, 15) of the two metal plates (10), each elongate member having a plurality of complementary fasteners (29, 146) adapted to cooperate each time with one of the anchoring members (21, 121) of the support surface for anchoring the frame to the support surface, the clamping means (46, 146) being adapted to engage the frame with the anchoring members (21, 121) so as to clamp the first and second metal plates (10). against the support surface along the overlapping marginal areas (14, 15) of the first and second metal plates. Apparatus according to claim 10, wherein the clamping means (146) is adapted to clamp the two elongated frame members (140) against the metal plates at the anchoring members (121) of the support surface. Apparatus according to claim 11, further comprising a rigid gantry (131) connected to the two elongated frame members (140) and extending between the two elongated members to overlap the overlapping marginal areas (14, 15). two metal plates, the movable support (60, 134) being mounted on the gantry. An apparatus according to claim 12, wherein at least one of said elongate members (140) includes a guide rail (133, Fig. 4) for slidably guiding the gantry (131) along said at least one elongate member. of the chassis. An apparatus according to claim 12, wherein the gantry (131, Fig. 6) comprises a guide rail (133) parallel to the elongated frame members (140) for slidably guiding the movable support (134) relative to at the portico. Apparatus according to claim 13 or 14, wherein the gantry (131) includes a second guide rail (60) for guiding the movable support (134) transversely between the two elongate frame members (140). Apparatus according to claim 9 or 10, further comprising a support beam (40) disposed parallel to the elongate frame member (32) and movably connected to the frame (31, 32), the clamping means ( 46) being able to exert a force away from the frame (31, 32) of the support surface against the anchoring members (21) to cause a pressure of the support beam (40) in the direction of the support surface by reaction. 20 Apparatus according to claim 16, wherein the support beam (40) is connected to the frame by a lever (43) pivotally mounted to an elongate member (32) of the frame about an axis (44) substantially parallel to the elongate member, the clamping means (46) being arranged to pivot the lever relative to the frame. Apparatus according to claim 17, wherein the lever has an end portion (48) extending from the other side of the frame (32) relative to the support beam (40), the means of clamping comprising a spacer element (47) movably connected to the end portion of the lever and able to bear against the metal plate (10) to exert a force tending to move the end portion (48) away from the lever ( 43) of the support surface. 30 19. Apparatus according to one of claims 16 to 18, wherein a sealed casing (51) is arranged on the surface of the support beam (40) facing the support surface, the apparatus further comprising means pressurizing fluid to generate fluid pressure within the sealed casing. 20. Apparatus according to claim 19, wherein the pressurizing means are adapted to circulate a cooling liquid inside the sealed casing (51). 21. Apparatus according to one of claims 9 to 20, wherein an elongated member of the frame each comprises a plurality of feet (32) provided with complementary fasteners (29) adapted to cooperate with the anchoring members (21). ). 22. Apparatus according to one of claims 9 to 21, wherein the complementary fastener (146) each comprises a member selected from a nut for cooperating with a threaded rod of the support surface and a threaded rod for cooperate with a threaded bushing of the support surface. 23. Apparatus according to one of claims 9 to 22, wherein the complementary fastener (29) each comprises a member selected from a notched tab intended to cooperate with a wide-head rod of the support surface and a wide head rod for cooperating with a notched tab of the support surface.