Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/06—Resistance welding; Severing by resistance heating using roller electrodes
  • B23K11/061—Resistance welding; Severing by resistance heating using roller electrodes for welding rectilinear seams
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K11/00—Resistance welding; Severing by resistance heating
  • B23K11/30—Features relating to electrodes
  • B23K11/3036—Roller electrodes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B25/00—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby
  • B63B25/02—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods
  • B63B25/08—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid
  • B63B25/12—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed
  • B63B25/14—Load-accommodating arrangements, e.g. stowing, trimming; Vessels characterised thereby for bulk goods fluid closed pressurised
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2101/00—Articles made by soldering, welding or cutting
  • B23K2101/006—Vehicles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K2103/00—Materials to be soldered, welded or cut
  • B23K2103/02—Iron or ferrous alloys
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2203/00—Vessel construction, in particular walls or details thereof
  • F17C2203/03—Thermal insulations
  • F17C2203/0304—Thermal insulations by solid means
  • F17C2203/0358—Thermal insulations by solid means in form of panels
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2209/00—Vessel construction, in particular methods of manufacturing
  • F17C2209/22—Assembling processes
  • F17C2209/221—Welding
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2221/00—Handled fluid, in particular type of fluid
  • F17C2221/03—Mixtures
  • F17C2221/032—Hydrocarbons
  • F17C2221/033—Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
  • F17C2223/0146—Two-phase
  • F17C2223/0153—Liquefied gas, e.g. LPG, GPL
  • F17C2223/0161—Liquefied gas, e.g. LPG, GPL cryogenic, e.g. LNG, GNL, PLNG
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
  • F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
  • F17C2223/033—Small pressure, e.g. for liquefied gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
  • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
  • F17C2270/00—Applications
  • F17C2270/01—Applications for fluid transport or storage
  • F17C2270/0102—Applications for fluid transport or storage on or in the water
  • F17C2270/0105—Ships
  • F17C2270/0107—Wall panels

Definitions

• the subject of the invention is the production of sealed and thermally insulating tanks intended more particularly, but not exclusively, for the transport by sea of liquefied gases or cryogenic liquid and, more specifically, for the transport of liquefied natural gases with a high methane content (LNG). ) or petroleum (LPG).
• LNG high methane content
• LPG petroleum
• the invention relates here to the welding of a waterproof membrane of such a tank, more particularly the invention provides a solution for achieving optimal welding between two adjacent strakes of the membrane as well as two anchoring wings, said two strakes having raised edges and the welding between these two adjoining strakes being carried out at these raised edges.
• anchor wing and “weld support” will be used interchangeably to designate the same element, the function of which is both to provide a means of anchoring the membrane (its strakes) to the block. thermal insulation and serve as a weld support for fixing with each of the two adjacent strakes.
• FR 2798358, FR 2709725, FR 2549575 storage or transport tanks for liquefied gases at low temperature including the or each waterproof membrane, in particular a primary waterproof membrane in contact with the product contained in the tank, consists of thin metal sheets which will be carried by a thermally insulating barrier. These thin metal sheets are tightly connected to each other to ensure the tightness of the tank.
• FIG. 1 illustrates a known method of fixing said metal sheets to the thermally insulating barrier in this type of tank.
• an upper surface 101 of the thermally insulating barrier has a groove 102 developing in the thickness of the thermally insulating barrier from the support surface 101.
• This groove 102 has in the thickness of the thermally insulating barrier a retaining zone formed by a groove 103 which develops parallel to the support surface 101.
• This groove 103 develops at one end of the groove 102 opposite the support surface 101 in the thickness of the thermally insulating barrier, the groove 102 having a cross section in the shape of an inverted "T" whose base is formed by the groove 103.
• An anchoring wing 104 in the shape of an “L” is inserted in the groove 102.
• This anchoring wing 104 has a base 105 housed in the groove 103 so as to retain the wing of anchoring 104 on the thermally insulating barrier in a direction perpendicular to the support surface 101.
• the anchoring wing 104 also comprises an anchoring branch 106 of which a lower part 107 is contiguous of the base 105 and an upper part 108 protrudes above the support surface 101.
• Two metal sheets 109 are arranged on either side of the anchoring wing 104. These metal sheets 109 each have a flat central portion 110 bearing on the support surface 101 (for the sake of readability of the figure, the support surface 101 and the metal sheets 109 are shown in Figure 1 with a gap). These metal sheets 109 also have raised side edges, hereinafter called raised edges 111. A raised edge 111 of each of the two adjacent metal sheets 109 is welded on either side of the anchoring branch 106 of the anchor wing 104.
• the raised edges 111 thus form, with the anchoring wing 104, bellows making it possible to absorb the forces associated with the contraction of the waterproof membrane, for example when loading cryogenic liquid into the tank.
• an anchoring wing 104 constitutes a fixed fixing point for each raised edge 111.
• the anchoring wing 104 being biased in two opposite directions by the raised edges 111, it remains substantially static in the tank. . Consequently, the anchoring of the raised edges 111 on the support surface 101 via the anchoring wings 104 is substantially fixed in the direction perpendicular to the raised edges 11 1. The flexibility of the waterproof membrane is therefore limited.
• the present invention intends to remedy the shortcomings of the state of the art by proposing a particularly effective solution for carrying out the welding between two adjacent strakes, when each has or comprises an anchoring wing connecting or fixing it to the insulation block. thermal.
• the present invention relates to a method for welding a waterproof and thermally insulating tank membrane, in which a waterproof and thermally insulating tank comprises at least one waterproof metal membrane and a thermally insulating block comprising at least one thermally insulating barrier adjacent to said membrane, in which:
• At least two metal strakes of the waterproof membrane, carried by a support surface of the thermally insulating barrier, are in the form a profiled part comprising a flat central portion resting on the support surface and two raised lateral edges projecting from the support surface, and
• the method according to the invention characterized in that a conductive strip is inserted between the two aforementioned metal welding supports and in that, subsequently, the joints are welded together, in pairs, by welding with the thumbwheel each of the two raised lateral edges of the two adjacent metal strakes respectively with one of said metallic welding supports, interposed between said adjacent raised edges.
• the welding method according to the invention makes it possible to ensure the mechanical continuity and the sealing of the weld bead, to weld the length of the raised edges without stopping or resuming thanks to the electrical continuity and not to merge the two. weld supports at the welds with the two edges raised. This process is also compatible with current welding machines and therefore makes it possible to conserve existing equipment, limit investment and manage the machine fleet.
• a simultaneous weld (at the same time) is carried out of each of the two raised edge / weld support assemblies.
• “Seam welding” is understood to mean welding in which the parts are assembled by application of an electric current (the application of direct current or not) and of pressure, knobs against the surface to be welded.
• At least one of the welding supports preferably both, consists of an anchoring wing so as to anchor the waterproof membrane to the thermally insulating barrier of the thermal insulation mass;
• the anchoring wing is in the form of an L and has a longitudinal portion and a lower portion engaged with the thermally insulating barrier;
• the lower portion of the anchoring wing extends, parallel to the middle portion of the metal strakes, in a recess in the thermally insulating barrier of the thermal insulation mass;
• said welding supports Prior to the welding of each of the above edges raised with one of said welding supports, said welding supports have been fixed by welding in a sealed manner to each other;
• the junction of the two adjacent strakes with the two metal anchoring wings has, thanks to the different welding points, a profile or a section in W.
• a junction has a double-bellows function which gives it significant elasticity properties allowing the waterproof membrane, in particular at this level, to support or absorb very strong thermal gradients, resulting in particular in (thermal) contractions particularly significant.
• the seam welding of each of said two adjacent raised edges with respectively one of said welding supports is carried out at a speed of between 1.5 meters per minute (m / min) and 2.5 m / min , preferably at a speed of 1.8 m / min;
• the above raised edges are made of Invar® or steel containing at least 20% manganese, preferably at least 25% manganese, even more preferably 28% manganese;
• the thickness of the raised edges is between 0.5 and 0.8 millimeter (mm), preferably equal to 0.7 mm; - when the raised edges, possibly the welding supports have such a thickness (of 0.5 and 0.8 mm), during the seam welding, the intensity of the current is between 1.8 and 3.2 kiloamperes (kA), preferably between 2.2 and 2.8 kA, and the pressure force exerted by each wheel against respectively a raised edge is between 1.2 and 2.8 bars, preferably between 2 and 2, 5 bars;
• the thickness of the raised edges preferably also the thickness of the aforementioned welding supports, is between 0.9 and 1.2 millimeter (mm), preferably equal to 1 mm;
• the welding supports have such a thickness (of 0.9 and 1.2 mm)
• the intensity of the current is between 2.7 and 3.8 kA , preferably between 3 and 3.5 kA
• the pressure force exerted by each wheel against respectively a raised edge is between 3.5 and 5 bars, preferably between 4 and 4.5 bars;
• the electric current of the seam welding does not circulate continuously, preferably said electric current circulates during a time range corresponding to 60% to 80% of the time at (or for) a constant frequency, even more preferably for two thirds (2/3) of the time at (or for) a constant frequency;
• the conductive strip consists of a material or an alloy of materials with a high melting point, greater than the melting point of the raised edges and the welding supports.
• the conductive strip is (essentially comprises) copper, a molybdenum-based alloy, a tungsten-based alloy or graphite, preferably copper.
• the invention also relates to a system for welding a sealed and thermally insulating tank membrane, the system comprising a seam welding device comprising two seams, optionally means for holding said seams against a surface to be welded, and a wall of a sealed and thermally insulating tank comprising:
• the seam welding device carrying out at least one welding respectively between one of the above raised edges and one of the above welding supports
• the system according to the invention being characterized in that the welding device comprises a conductive blade intended to be inserted between the two welding supports so as to carry out the welding of each of the above two adjacent raised side edges with one of said welding supports respectively, interposed between said adjacent raised edges.
• the invention also relates to a sealed and thermally insulating tank integrated into a support structure, comprising a sealed and thermally insulating tank comprising at least one waterproof metal membrane composed of a plurality of metallic strakes and a thermally insulating block comprising at least one thermally barrier. insulator adjacent to said membrane, in which:
• At least two metal strakes of the waterproof membrane, carried by a support surface of the thermally insulating barrier, are in the form of a profiled part comprising a flat central portion resting on the support surface and two raised lateral edges making protruding from the support surface, and
• the tank according to the invention is characterized in that each of the two adjacent raised lateral edges of the two adjacent metal strakes and respectively one of said weld supports, interposed between said adjacent raised edges, are welded together in pairs waterproof, by seam welding.
• the production of a weld between a strake (its raised edge) and an anchoring wing is certainly known as such, from the document FR 3054872, but the weld point present, with the use of the method according to the present invention, a section with a shape different from that of this prior art.
• the section of the weld point has a shape substantially oval (and not symmetrical as in the state of the art) whose protuberance (protuberance or hump) is on the side of the strake, that is to say on the side where the wheel was positioned during welding. It will be noted that, in the event that two knurls, arranged on either side of the welding point, are used, the welding point has a symmetrical shape. This section of slightly different shape - the appended FIG.
• the invention also relates to a ship for the transport of a cold liquid product, the ship comprising a double hull and a sealed and thermally insulating tank as briefly described above, arranged in the double hull.
• the vessel according to the invention comprises at least one sealed and insulating tank as described above, said tank comprising two successive sealing barriers, one primary in contact with a product contained in the tank and the other secondary disposed between the primary barrier and a supporting structure, preferably constituted by at least a portion of the walls of the ship, these two sealing barriers being alternated with two thermally insulating barriers or a single thermally insulating barrier disposed between the primary barrier and the load-bearing structure.
• GMO International Maritime Organization
• the tank contains a Liquefied Natural Gas (LNG) or a Liquefied Gas (GL).
• LNG Liquefied Natural Gas
• GL Liquefied Gas
• the invention also provides a method of loading or unloading of such a vessel, in which a fluid product is conveyed through isolated pipes from or to a floating or land storage installation towards or from the tank. of the ship.
• the invention also provides a transfer system for a fluid product, in particular cold liquid, the system comprising the aforementioned vessel, insulated pipes arranged so as to connect the tank installed in the hull of the vessel to an installation floating or terrestrial storage and a pump to drive a flow of fluid through the insulated pipes from or to the floating or terrestrial storage facility to or from the vessel of the ship.
• - Figure 1 is a sectional view of a waterproof metal membrane anchor wing of the prior art, said anchor wing being anchored in a thermally insulating barrier of a sealed and thermally insulating tank;
• - Figure 2 is a sectional view of two metal membrane anchoring wings, the two anchoring wings having been welded together before their introduction into the thermal insulation block, this figure illustrating a portion of wall d 'a tank, at two adjacent strakes, before the application of the welding process according to the invention;
• - Figure 3 is a sectional view identical to Figure 2, this time the elements suitable for implementing the welding process according to the invention being visible in this figure;
• FIG. 4 is a sectional view, showing the elements visible in Figures 2 and 3, of a portion of the wall of the sealed and thermally insulating tank, after the implementation of the welding process according to the invention;
• FIG. 5 is a cutaway schematic representation of an LNG tank and a loading / unloading terminal of this tank.
• the gas may in particular be a liquefied natural gas (LNG), that is to say a gaseous mixture mainly comprising methane as well as one or more other hydrocarbons, such as ethane, propane, n-butane, i -butane, n-pentane, i-pentane, neopentane, and nitrogen in small proportion.
• LNG liquefied natural gas
• the gas can also be ethane or a liquefied petroleum gas (LPG), that is to say a mixture of hydrocarbons resulting from the refining of petroleum comprising essentially propane and butane.
• the waterproof membrane rests on a support surface formed by a thermally insulating barrier of the tank.
• This waterproof membrane has a repeated structure, alternately comprising, on the one hand, sheet metal strips, forming strakes, arranged on the support surface and, on the other hand, elongated welding supports linked to the support surface and s' extending parallel to the sheet metal strips over at least part of the length of the sheet metal strips.
• the sheet metal strips have raised side edges arranged and welded against the adjacent welding supports.
• Such a structure is for example used in the type of LNG tanks NO 96 ® marketed by the Applicant.
• the raised edges of the strakes are preferably arranged in a longitudinal direction perpendicular or parallel to the longitudinal direction of the ship.
• the raised edges constitute bellows making it possible to absorb the contraction forces in a longitudinal direction of the ship or a transverse direction perpendicular thereto.
• the sheet metal strips and the welding supports are interrupted at the angles, for example as described in document WO 2012/072906 or else FR2724623.
• the waterproofing membrane (strakes), one of the waterproofing membranes or the waterproofing membranes can be made of a metal chosen from stainless steel, aluminum, Invar ® , that is to say an alloy of iron and nickel whose coefficient of expansion is typically between 1, 2.10 6 and 2.10 6 K 1 or an alloy of iron with high manganese content whose coefficient of expansion is from 7 to 9.10 6 K 1 .
• a material having a coefficient of thermal contraction less than 16.10 6 / K is chosen for applications in which the liquid gas is at a temperature between -45 ° C and -100 ° C.
• Figures 2 to 4 show a sectional view of a wall of a sealed and thermally insulating tank at the connection between two adjacent metal strakes 1, 2 of a sealed membrane of the tank wall and two welding supports 3, 4 anchored on a thermally insulating barrier 5 of the thermal insulation mass of the tank wall.
• a thermally insulating barrier 5 is formed of juxtaposed insulating elements.
• suitable insulating elements are described in document W02012 / 072906.
• This thermal barrier 5 of the thermal insulation mass can be produced in one or more thicknesses responding to the function of thermally isolating the contents of the tank from its environment.
• the material or materials which may also be present in such a thermal insulation mass consist, for example, of polymer foams, such as polyurethane foams, polystyrene or polyethylene, preferably at very low density (LDPE), manufactured glass wool, loose glass wool, melamine foams, aerogels, polyester wadding in mattresses or in bulk.
• polymer foams such as polyurethane foams, polystyrene or polyethylene, preferably at very low density (LDPE), manufactured glass wool, loose glass wool, melamine foams, aerogels, polyester wadding in mattresses or in bulk.
• the thermal insulation block is conventionally anchored to the supporting structure, not shown in the appended figures, for example of a ship or a barge, by retaining members.
• Each of the insulating elements forming the thermal insulation block here has the shape of a rectangular parallelepiped having two large faces, or main faces, and four small faces, or lateral faces. More specifically, vimres 1, 2 adjacent metal rests on a support surface 10 of the thermal insulation block (or of the thermally insulating barrier 5). This support surface 10 is formed by the upper face of the thermally insulating barrier 5.
• the welding supports 3, 4 are anchored in the insulating element of the thermally insulating barrier 5 of the thermal insulation block.
• the upper face of the block (thermally insulating barrier 5) has a groove 11 which has a section in the shape of an inverted "T".
• the upper part of the thermally insulating barrier 5 can include a plywood or a composite material in which the groove 11 is housed.
• a retaining zone 12 develops in the thickness of the thermally insulating barrier 5 of the thermal insulation mass. insulator parallel to the support surface 10.
• the weld supports 3, 4 are inserted by sliding in the grooves 11 of the thermal insulation block.
• the weld supports 3, 4 are thus slidably anchored on, or in, the thermal insulation block 5, in the longitudinal direction of the weld supports 3, 4.
• the retaining area 12 is formed by two grooves 13, 14 developing on either side of the groove 11, at the lower end of said groove 11 .
• the welding supports 3, 4 consist of two metal anchoring wings, preferably of identical shape and nature (material). These metal anchoring wings 3, 4 are essentially symmetrical with respect to a plane perpendicular to the support surface 10 and parallel to a longitudinal direction of the groove 11. Each metal anchoring wing 3 or 4 has a section in the form of “L” comprising a base 21 and an anchoring branch 22. The base 21 corresponds to the lower portion of the metal anchoring wing 3, 4 while the anchoring branch 22 corresponds to the longitudinal portion of these same metal anchor wings 3, 4.
• each metal anchoring wing 3, 4 is housed in a groove 13, 14, or recess, respectively of the groove 11.
• the bases 21 of the metal anchoring wings 3, 4 develop parallel to the surface of support 10.
• a lower part of the anchoring branch 22 of one of the metal anchoring wings 3 or 4 is joined to the other anchor branch 22 of the metal anchor wing 3 or 4.
• the lower portions of the anchor branches 22 of the two metal anchor wings 3, 4 are welded between them by a weld line 23.
• This weld line 23 is preferably housed, or located, in the thickness of the thermally insulating barrier 5 (mode shown in FIGS.
• this weld line 23 is situated at the level of the support surface 10, or even slightly above the latter 10.
• An upper part of the anchoring branch 22 of each of the metal anchoring wings 3, 4 projects from the support surface 10 from the groove 11, towards the inside of the tank.
• each metallic strake 1, 2 is arranged on the support surface 10 on either side of the weld supports 3, 4.
• Each metallic strake 1, 2 has a flat central portion 6, 7.
• Each strake 1, 2 metallic has two raised edges 8, 9 located along two opposite longitudinal edges of the flat central portion 6, 7.
• a single raised edge 8, 9 of each of the two metal strakes 1, 2 is shown in Figures 2 to 4.
• Each raised edge 8, 9 projects from the support surface 10.
• FIG. 2 illustrates the state in which the various elements 1, 2, 3, 4, 5, 6, 7, 8, 9 are positioned, that are the two adjacent strakes 1, 2, 6, 7, 8, 9, the two anchoring wings 3, 4 (fixed together here at the welding point 23) and the thermal insulation block 5, before the application of the welding process according to the invention.
• FIG. 3 illustrates the elements specific to said welding process and device according to the invention, adding to the above elements of FIG. 2.
• a conductive strip 30 (the expression “conductive strip” can also be used to designate the “conductive strip” 30) as well as two welding knobs 31, 32, said conductive strip 30 and said knobs 31, 32 being connected to a welding apparatus with the wheel, not shown in the accompanying figures.
• the conductive strip 30 is placed in the space defined between the two anchoring wings 3, 4, more precisely at the space between the anchoring branches 22, of each of the anchoring wings 3, 4, projecting from the support surface 10.
• the two knobs 31, 32 are placed contiguous against the face / external side (face / side being opposite to that where the anchoring wings are located) of each of the raised edges 8, 9 of the two strakes 1, 2.
• a pressure of the knobs 31, 32, against each of the raised edges 8, 9, directed towards the conductive strip 30, it is possible to pass a current in the thickness constituted by a wheel 31 or 32, a raised edge 8 or 9, an anchoring wing 3 or 4 and the conductive blade 30 so as to carry out a welding with the wheel between each of the raised edges 8, 9 and the adjacent anchor wing 3, 4.
• the choice of the current intensity as well as the pressure exerted by the knurling wheels is determined, after multiple experiments, to ensure optimum seam welding.
• the current intensity and pressure ranges are in accordance with those presented above, for defined thicknesses and nature of materials.
• one knob 31 or 32 serves as a positive terminal and the other knob 31 or 32 as a negative terminal,
• the two knobs 31, 32 serve as a positive terminal and the conductive strip 30 as a negative terminal
• the conductive strip 30 serves as a positive terminal and the two knobs 31, 32 as a negative terminal.
• the conductive strip 30 can also be used as a (simple) electrically conductive element.
• one of the wheels 31 or 32 serves as a positive terminal and the other wheel 31 or 32 as a negative terminal, the conductive strip 30 having no polarity.
• the conductive strip 30 consists of an electrically conductive material which must have a high melting point and be sufficiently resistant mechanically not to deform under the pressure forces of the knurls 31, 32. Copper is an economically advantageous material but others materials are possible, such as molybdenum (molybdenum-based alloys), tungsten (tungsten-based alloys) or graphite.
• the raised edges 8, 9 of strakes 1, 2 advantageously have a thickness of 0.7 millimeter (mm) like the anchoring wings 3, 4, at least at the level of the anchoring branch 22 coming weld to the corresponding raised edge 8, 9.
• mm millimeter
• each raised edge 8, 9 of each of the two adjacent metal strakes 1, 2 is welded to an anchoring wing respective metal 3, 4 forming a weld support. More particularly, each raised edge 8, 9 is welded by a weld line 40, 41 to the upper portion of a single metal anchoring wing 3, 4.
• the technique described above for producing a waterproof membrane for a sealed and thermally insulating tank can be used in different types of tanks, for example to constitute the waterproof membrane for an LNG tank in a land installation or in a floating structure such as a LNG tanker or other.
• a cutaway view of an LNG tanker 70 shows a sealed and insulating tank 71 of generally prismatic shape mounted in the double hull 72 of the ship.
• the wall of the tank 71 comprises a primary waterproof barrier intended to be in contact with the LNG contained in the tank, a secondary waterproof barrier arranged between the primary waterproof barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary waterproof barrier and the secondary waterproof barrier and between the secondary waterproof barrier and the double shell 72.
• loading / unloading lines 73 arranged on the upper deck of the ship can be connected, by means of appropriate connectors, to a maritime or port terminal for transferring a cargo of LNG from or to the tank 71.
• FIG. 5 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and a shore installation 77.
• the loading and unloading station 75 is a fixed offshore installation comprising an arm mobile 74 and a tower 78 which supports the mobile arm 74.
• the mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipes 73.
• the mobile arm 74 can be adjusted to suit all LNG tankers .
• a connection pipe, not shown, extends inside the tower 78.
• the loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore installation 77.
• This comprises liquefied gas storage tanks 80 and connection pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75.
• the submarine pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the shore facility 77 over a long distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a long distance from the coast during loading and unloading operations.
• pumps on board the ship 70 and / or pumps fitted to the shore installation 77 and / or pumps fitted to the loading and unloading station 75 are used.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Ocean & Marine Engineering (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=63896356

Family Applications (1)

Country Status (6)

Family Cites Families (13)

• 2018
  • 2018-07-26 FR FR1856991A patent/FR3084270B1/fr active Active
• 2019
  • 2019-07-22 WO PCT/FR2019/051820 patent/WO2020021189A1/fr active Application Filing
  • 2019-07-22 EP EP19761914.1A patent/EP3826796A1/de active Pending
  • 2019-07-22 KR KR1020217004065A patent/KR20210031938A/ko unknown
  • 2019-07-22 SG SG11202100789QA patent/SG11202100789QA/en unknown
  • 2019-07-22 CN CN201980049914.8A patent/CN112543691B/zh active Active

Also Published As

Similar Documents

Legal Events