SE438024B - HORN CONSTRUCTION AT A TANK FOR A CRYOGENIC LIQUID GAS - Google Patents

Description

Malins in close contact with the surface of the adjacent heat-absorbing layer and above the internal pressure from the low temperature liquid gas via the heat-insulating layer to the outer container or hull of the tanker.

Of particular importance is that the container and its insulation system must be able to withstand the thermal stresses formed by the cold liquid and the transients that arise during the cooling and heating cycles generated during loading and unloading of the liquid, and the mechanically induced stresses from the ship's hull or displacement. of the container during operation.

Critical portions of such a cryogenic insulation system for supporting the primary liner are at the corners where the load to which the liner is subjected is transferred to the container wall or ship's hull. In membrane systems of the above type designed to contain cryogenic liquids, the corners must be secured against movement generated by membrane contraction and deflection of the support structure. These corner constructions must withstand loads at different angles and in a number of different directions with minimal heat transfer to the cold contents. However, one of the main difficulties of iii? l'f? -iäi; l "-, = ^ t iíätišliíšâ iiäfiitöiišïiiííiííiiâilâ-f fi â ëiili fi ï Élíiišâïiê iéliiiä ïêiíiliií ätt 'šiibåššâ innnnnnnännning bildning imnan increases the cost of such a cryogenic insulation system.

According to the present invention, there is provided a container for cryogenic liquid gases comprising a container wall, at least one fiber-reinforced plastic insulating layer located inside said container wall, a metal liner which can withstand low temperatures in contact with the inner side of said foam insulating layer, the container has corners and comprises at least one corner construction. This corner structure comprises a corner support means located in said foam insulation layer adjacent to the metal lining at the corner of the container wall, an angle member of a metal which can withstand low temperatures, a member connecting the metal liner to the angle member, a member connecting the angle member to the corner support member, a plurality metal strips or metal hand. a device connecting the metal strips at its one end to the vinixil body, or a device connecting metal strips at its other end to the wall of the container, the strips being located substantially flush with the liner and transmitting loads from the metal liner to the container wall.

The corner construction can be arranged in corners of the tank with different angles. Thus, the corner structure can be incorporated into corners at 90 °, the angle member having an angle of 900 and the first series of bands being located at an angle of 900 to the second set of bands. If the corner structure according to the invention is arranged in a corner with an acute angle, the angle member forms an acute angle and the first set of bands are located at the same acute angle relative to the second set of bands.

If the corner structure according to the invention is arranged at an obtuse angle of the container, the angular means has the same obtuse angle and the first set of bands are located at an obtuse angle relative to the second set of bands. In some cases, k., Www ... ... feed LW l0 15 20 30 35 40 3 79Û2769 '"¿i i as described in more detail below, only one set of bands may be required at one corner.

In a preferred embodiment, a corner support panel is arranged around the corner construction to support the foam insulation at this corner. Alternatively, the foam insulation can be connected directly to the inner wall of the container or ship's hull.

The corner structure for supporting the membrane or liner can be used in conjunction with a metal membrane having a low coefficient of thermal expansion to contain cryogenic liquids in any type of container or storage tank for marine or onshore use.

The use of metal strips or fingers formed of materials with low thermal conductivity and high strength, such as stainless steel, in connection with a membrane formed of a material with a low coefficient of thermal expansion, such as nickel steel, results in an efficient transfer of membrane loads in different directions and angles from the inner metal membrane to the outer wall of the container or ship's hull, and provides minimal heat loss and minimal destruction of the foam insulation, thereby allowing easy installation of the foam insulation in and around the corner structures. The width and / or thickness of the bands or fingers can be dimensioned to absorb and correspond to expected load intensities. Furthermore, the bands extending in one direction may be wider and / or thicker than the bands in other directions of the corner structure. Furthermore, when a second or inner liner is used, such as a fiberglass fiber, in conjunction with the primary metal liner, the use of straps or fingers in the corner structure of the invention to connect the primary liner to the container wall or hull allows the fiberglass liner to pass through the foam at the corner construction, thereby ensuring the continuity of this fiberglass lining.

The invention will become more apparent from the following description of certain preferred embodiments of the invention with reference to the drawings. In this case, Fig. 1 is a perspective view showing a methane container or tank containing an insulation system and a corner construction according to the invention. Fig. 1A shows a preferred type of fiber reinforced insulation material called "3D" foam insulation and used in the system of Fig. 1. Fig. 2 is a cross section through a 900 corner portion of the tank taken along line 2-2 of Fig. 1 and shows the corner construction. according to the invention.

Fig. 3 shows the corner construction according to the invention which is used in the foam insulation system according to Fig. 2. Fig. 4 is a plan view of the corner construction according to Fig. 3.

Fig. 5 is a perspective view showing the alternating relationship of one set of bands or fingers relative to the other set of bands in the corner structure.

Fig. 6 is a cross-section similar to Fig. 2 and shows the use of the corner construction according to the invention at a corner of a container which forms an obtuse angle.

Fig. 7 is a cross-section similar to Fig. 2 and shows the use of the corner construction according to the invention at a corner which forms an acute angle. Finally, Fig. 8 is ES _._.__.._._...-........-. .. - .. auam fl -..- wg 10 15 20 25 30 35 40 79027694; Fig. 4 is a cross-section taken along the line 8 ~ 8 in Fig. 1 and shows a corner according to the invention which uses only one set of bands.

The drawings in Fig. 1 show a cryogenic liquid tank or LNG tank having an inner hull 12 and an insulation system 13 located in the hull. This insulation system consists of an outer, fiber-reinforced foam insulation layer 14 located against the inner hull 12, and an inner, fiber-reinforced foam insulation layer 16. These fiber-reinforced foam insulation layers are preferably three-dimensional glass fiber-reinforced polyurethane foam layer. This fiber-reinforced insulating material consists of blocks or plates of closed-cell polyurethane foam, which include layers of glass fiber, each fiber layer extending in both a horizontal and a transverse direction, X- and Y-reinforcing fibers, and layers of fibers extending in a vertical direction. direction, Z-reinforcing fibers.

Fig. 1A shows this type of material consisting of block 17 of closed cell polyurethane foam with layers of glass fibers 19 embedded in the foam and with exposed fiber ends 21 to facilitate the joining of the fiber-reinforced polyurethane blocks 17 to a structural member such as a tank wall. The polyurethane block 17 has second glass fibers 23 extending vertically with exposed fiber ends 25 to facilitate the joining of individual blocks to each other, and layers of other fibers 27 extending horizontally and perpendicular to the fibers 19. This type of reinforcement is known as XYZ reinforcement. wherein the X-fibers are longitudinal fibers, the Y-fibers are transverse fibers, and the Z-fibers are vertical fibers, and the resulting reinforced foam is also known as "3D foam". Preferably, plates of such 3D polyurethane foam are joined together as at 13 in Fig. 2 by means of a suitable adhesive, preferably a polyurethane adhesive, to form the outer and inner insulating layers 14 and 16.

In Figs. 1 and 2 it can be seen that a thin primary liner or membrane 18 is located in contact with the inner 3D foam insulation layer 16 and can be connected thereto in any suitable manner, such as by means of mechanical fasteners including tongues 15 (see Fig. 8), which are received and held in position by means of tongue holding means in the form of pg-wood strips 17, which are glued to the foam insulation layer. The liner 18 is formed by a series of parallel sections or strips 19, which have upright flanges along their longitudinal edges, which flanges of adjacent strips are connected to each other. the lungs 15 are located between the flanges 21 of adjacent strips 19. This construction as described above does not form part of the present invention.

The primary membrane is preferably made of a material that can withstand low temperatures (has low thermal expansion), such as nickel steel, preferably high nickel steel, such as the material with the trade name Inva. The membrane 18 is made of a fluid-permeable material and forms an inner membrane vessel to contain the cryogenic liquid. A second liner 20 is inserted between the outer 3D foam insulation layer 14 and the inner 3D foam insulation layer 16. <_- u-. : - 10 3D 40 7902769--4 I Lä.

This liner may be a fiberglass cloth or a combination of a fiberglass cloth and a thin metal, for example aluminum, foil. This second liner may also be a resin-impregnated fiberglass cloth, for example impregnated with polyurethane resin, or ns such a resin-impregnated fiberglass cloth in combination with a polyvinyl fluoride film, of the brand Tedlarg. This second liner may be a non-perforated liner which prevents the penetration of cryogenic liquid from the inner foam insulation layer 16 to the X-outer foam insulation layer 14.

In Figs. 2-5 of the drawings, the corner construction according to the invention is shown in a 900 corner. At this corner there is an angle member 22, which like the primary membrane 18 consists of a material which is resistant to low temperatures and has a low coefficient of thermal expansion, such as nickel steel, preferably a high nickel steel, such as Invar, which is attached by welding at 24 to the primary membrane or lining l8. A support member or support 26 for the angle member 22 is provided in the inner foam insulating layer 1 adjacent to the angle member, the support member being attached at 28 to the foam. This support member or support member 26 is preferably made of plywood and consists of a pair of support members of plywood 30 and 32 located at an angle of 90 DEG relative to each other and in contact with the outer surfaces of the angle member 22.

The support member or support member 26 not only provides a support for the angle member 22 but also stabilizes the primary membrane 18 and provides a support for the weld.

The angle member 22 is attached to the support member or support member 26 by means of screws 34.

A first series of metal strips 36 are connected at their inner ends by welding at 38 to a surface 40 of the angle member 22 and a second set of metal strips 4; similar metal bands 36 are similarly connected at their ends by welding at 43 to the outer surface 44 of the angle member 22. The bands or fingers 36 and 42 are made of a material with low thermal conductivity (low thermal conductivity coefficient) and high strength, such as stainless steel and is intended for the transfer of loads from the primary liner 18 to the ship's hull l2. It can be seen from Fig. 3 that the first set of bands 36 and the second set of bands 42 are located at an angle of 900 relative to each other and that the first set of bands 36 is in substantially the same plane as the primary diaphragm 18 and the angular member 22 at one direction of the corner. and that the second set of belts 42 is in substantially the same plane as the primary liner 18 and the angular members 22 in the other direction of the corner.

From Figs. 4 and 5 it can be seen that the first set of bands 36 consists of a plurality of spaced parallel bands and that the second set of bands 42 likewise consists of a plurality of spaced parallel bands, which second set of bands are arranged alternately with respect to the first set of bands at the corner. It further appears that the inner ends of resp. bands 36 od142 are located in grooves 46 formed in resp. portions 30 and 32 of the support member 26 and thus the support member 26 acts as a base for welding the diaphragm 18 to the angle members 22 as indicated at 38 and 43. The fingers 36 and 42 are dimensioned especially with respect to the width, to absorb and correspond to predetermined load intensities to be transmitted from the primary feed 18 to the ship's hull 12.

The other ends of the fingers 36 are connected by welding 48 to a metal strip 50, which in turn is supported by a socket, such as the T-socket 52, which in turn is connected to the ship's hull 12. The metal strip or band 50 is mounted in a vertical position in a groove 54 (Fig. 2) in the upper portion of the T-socket 52 and is retained therein by an angle 56 which abuts the outer surfaces of the fingers 36 and is connected to the lower portion. of the T-socket by means of a bolt and nut 58.

The T-socket 52 is connected by means of welding 60 and a bolt 62 to the inner ship's hull 12 and a metal spacer 64 is inserted between the flat outer surface of the T-socket and the adjacent container wall or ship's hull 12. A similar system of components is used to secure the outer ends of the second set of straps 42 to the ship's hull 12 and includes elements 50, 52 and 56-64.

A corner support panel 66 is arranged and mounted on the two T-sockets 52 at the corner by means of sockets 62, to support the foam insulation layers 14 'and 16' at the corners. It should be noted that the corner support panel 66 is preferably made of a metal such as steel. Longitudinal support panels 68, preferably of plywood, are likewise arranged and connected to the bolt and nut joint 58 of the T-sockets 52 at opposite corners to support the main body of the outer and inner foam insulation layers 14 and 16 along the length and width of the tank. The panels 68 are spaced from the ship's hull 12. The insulating support panels 66 and 68, which keep the foam insulation system at a distance from the inner wall of the container or the ship's hull, provide a water pocket for confining water adjacent to the inner ship's hull.

Furthermore, next to the corners, as shown in Fig. 2, there is a member 70 arranged in the foam next to the ends of the primary liner 18, which seal 70 contains a plurality of gas purification channels 72 for discharging gases from the area behind the primary liner 18. These sockets 80 are supported on an element 74 arranged in a suitable groove 76 in the inner foam insulation layer 16, the support element 74 being preferably made of plywood and adhesively attached to adjacent foam insulation layers 16.

With particular reference to Fig. 2, there is shown the simple construction of the corner support device according to the invention consisting essentially of two series of bands or fingers 36 and 42, which are connected to the angle members 22 and to the T-socket 52, to allow fitting of the insulating layers. 14 'and 16' in the corners and around and between the bands or fingers 36 and 42 with a minimum of interruption or discontinuity of the foam insulation and without the need for specially designed sockets or small pieces of foam around the elements as required in the prior art . Furthermore, it can be seen that the straps or fingers 36 and 42 allow the passage of the secondary membrane 20 of, for example, fiberglass cloth at the corners, thereby ensuring structural continuity of this membrane. The corner construction according to the invention consists essentially of the bands 36 and 42, which at one end are connected to the angle members 22 and at the other end to the T-sockets 52 and this construction is specially designed to receive the high angular loads in the stretching direction and likewise to absorb compressive loads applied to the primary membrane. These bands or fingers preferably consist of a material with low thermal conductivity and high strength, such as steel, which in particular transmits the membrane loads in different directions and angles to the wall of the tank or ship's hull with a minimum of interruption or possible damage to adjacent foam insulation. .

It should be noted that both the primary membrane or liner 18 and the angle member 22 are made of a material, preferably high nickel steel such as Inva, which has a very low coefficient of thermal expansion. In contrast, the straps or fingers 36 and 42 have a higher coefficient of thermal expansion, but a lower coefficient of thermal conductivity and are stronger than the material of the diaphragm 18 and the angle member 22. This has the advantages that less heat is transferred from the outer tank structure to the primary diaphragm. and at the same time there is greater strength in the support structure to withstand and transfer loads from the primary membrane to the outer tank wall or hull. Another advantage is that by using the hand or fingers to support the primary membrane at the corners instead of larger simple pieces of metal, loads that develop in a longitudinal direction along the straps and shrinkage loads at the ends of the straps will be significantly reduced.

Fig. 6 shows the application of the simple but useful corner construction according to the invention at an obtuse angle of the tank or container. Thus, it is apparent from the figure that the angle member 78, which is connected to the primary liner 18 in the manner indicated above, forms an obtuse angle and that the two sets of metal strips 36 'and 42' are located at a similar obtuse angle relative to the angle member 48, the first the set of metal strips 36 'is located in substantially the same plane as the surface 18a of the primary membrane at the corner, and the other surface 18a' of the primary liner at the corner. The corner construction of the embodiment according to Fig. 6 is otherwise identical to the corner construction for 900 angle shown in Fig. 2.

Fig. 7 shows the application of the corner construction according to the invention to a corner of a tank or container in the form of an acute angle. In this embodiment, the angle member 80, which corresponds to the angle member 22, is formed at an acute angle at the corner and the first set of bands 36 'and the second set of bands 42' form a similar angle, the bands 36 'again being substantially in the same position. plane as a direction or surface 18 'of the primary liner 18 and the second set of bands 42' is in substantially the same plane as the second surface or direction 18a 'of the primary liner 18.

It should be noted that in the corner constructions according to Figs. 2, 6 and 7, two sets of bands or fingers are used, the projecting parallel strip flanges 21 of the primary lining strips 19 in both directions of the lining 18 at the corner being perpendicular. towards the corner, as shown in Fig. 1 next to the cross section taken along line 2-2.

In the case where the strip flanges in one direction or surface of the primary liner at the corner are perpendicular to the corner and the strip flanges in the other direction or the surface of the primary liner at the corner are parallel to the corner, only one set of fingers need be used to connect and support the liner portion. perpendicular to the corner. This is shown in Fig. 8 which shows the corner construction at a 135 ° corner of the tank in Fig. 1. In this embodiment it can be seen that the upright strip flanges Z1, which are connected to the surface 18a 'of the liner 18 in a direction of the corner are perpendicular towards the corner, while the upstanding strip flanges 21 ', which are connected to the surface 18a of the primary liner 18 in the other direction of the corner, are located parallel to the corner, as can be seen earlier from Fig. 1 at the cross-section taken along line 8-8.

Under the latter conditions of Fig. 8, only one set of metal strips 42 "similar to the strips 42 is required, which are connected to the angle member 82 and to the T-socket 52 ', the set of metal strips 42" in Fig. 8 being substantially in the same plane as the surface. 18a 'of the primary membrane containing strip flanges Z1 perpendicular to the corner. This corner structure uses fingers 42 "which support the primary liner portion 18a 'when subjected to loads. At the second surface or portion 18a of the primary liner at the corner and where the strip flanges 21' are located parallel to the corner, loads can be absorbed without the need for metal support. fingers such as 42 "at the corner, so that no metal fingers are used to connect the liner portion 18a 'at the corner to the container wall or ship's hull in this modification.

The corner construction of Fig. 8 is otherwise similar to that of Fig. 2 and uses substantially the same elements except that a plywood panel 86 is used at the corner to support the foam insulation layers 14 "and 16" at the corner instead of the metal support panel 66 in Figs. 2. This corner support panel 86 is mounted on stubs 88 connected to the inner ship's hull l2.

From the above, it will be appreciated that the invention provides an improved corner structure for supporting the primary liner of a cryogenic insulation system. Tanks and vessels are specially designed to transfer loads in different directions of the primary diaphragm to the inner hull using a simple structure substantially existing. of a plurality of parallel strips, which significantly reduces the complexity of the foam insulation at the corner structure and reduces heat leakage to the cold contents of the container. Although the cryogenic insulation system according to the invention is particularly suitable for use on ships or tankers, the system can be used in any container for cryogenic liquids, including barges, storage tanks, aircraft or spacecraft. The thickness of the 3D fiber-reinforced foam insulation in the system can be varied to limit the decoction to suit the need for special designs.

Hereinafter, preferred embodiments of the invention have been described for illustrative purposes and it will be appreciated that further modifications and variations may be made by one skilled in the art and that the described embodiments are not to be construed as limiting the invention. The invention is limited only by the following claims.

Claims (3)

10 15 20 - - - io PATENTKRAV 1. A corner construction in a container for a cryogenic liquid gas, comprising at least one heat-insulating layer arranged between an enclosing container wall and a metal liner which is resistant to cryogenic temperatures, which has corner-defining wall sections which communicate with the container wall via a a plurality of metal strips, characterized by a cryogenic temperature resistant angle member (22) of metal, the angle legs of which extend parallel to the corner defining wall sections of the container (12), the free ends of the angle legs each being located between the metal lining (18) and the heat insulating layer (16), and further wherein the angle member (22) of metal is connected to the container wall (12) via said plurality of metal strips (36, 42), each such metal band (see, 42) being internally connected. with the outer surface possibly an 'angle leg' of said angle means (22) of metal and with the container wall (12) and extending parallel to the plane of the angle leg to which the metal band is attached. Corner construction according to claim 1, characterized in that the plurality of metal strips (36, 42) comprise a first row of metal strips (42) arranged parallel to spaces in the plane of the outer surface of one of the legs of the angle member (22) of metal and a second row of metal strips (36) arranged parallel to spaces in the plane of the outer surface of the second leg of the angle member (22) of metal. Corner construction according to claim 2, characterized in that said metal strip (36) for the second row alternates with the metal strips (42) for the first row.