NO138517B - SUPPORT DEVICE FOR A CONTAINER IN SHIPS - Google Patents

Description

This invention relates to a support device

for a container in the form of a body of rotation with a vertical axis for installation on board ships, consisting of an annular structure arranged between the upper and lower container shells and supported by a circumferential skirt which is rigidly and continuously connected to the structure and surrounds the lower container shell with spacing.

The containers or tanks can be spherical or cylindrical bodies of revolution with a spherical or ellipsoidal top part or they can comprise combinations of these geometric shapes. Tanks of this type are particularly suitable for the storage and/or transport of liquefied gas (liquefied gas) under pressure, as the ratio between the tank's surface area and volume is small and their walls work predominantly under tensile stress without significant bending moments or shear stresses in the walls. This contributes to the tank's weight being relatively small and the manufacturing costs being correspondingly low.

From DT-DS 2D 50 759, a support device is known which consists of a cylindrically shaped skirt which is connected to the wall of the container and is either complete or provided with a break-through. The connection takes place over an equatorial, ring-shaped construction which forms part of the container wall and has an outer step to which the skirt is connected. - As the outer step and thus the skirt is connected to the container over a certain distance, a moment arises which seeks to twist the ring-shaped construction's cross-section about its midpoint in such a way that the inner ring part is moved downwards and the outer ring part upwards.

In this way, significant bending moments will be transferred to the container wall. For this reason, such a support device cannot be used for containers with large dimensions.

According to DT-AS 10 29 254, the support also includes a skirt which is similarly connected to the container over a distance. In addition, the skirt is equipped with a conduit for a cooling medium. Thereby, a relief of the skirt is achieved by displacing the thermal stresses to another place, but in this case too reinforcement must be provided, which entails certain new problems.

In the case of the support device shown and described in DT-OS 19 2B 496, a number of spoke-like elements are attached to the container wall in the equatorial plane and are supported in a radially displaceable manner. - Although this system does not transfer any significant bending moments to the container, high stresses do occur in the places where the elements are attached. Furthermore, the individual elements are not capable of absorbing large, side-directed shear forces, so that the container size is also limited with this system.

The purpose of the invention is to provide a support without the above-mentioned disadvantages, which is achieved by the fact that, in order to avoid distortions of the ring construction as a result of the skirt attacking at a distance from the ring construction, a further skirt is attached which surrounds the first skirt concentrically with an intermediate distance .

The ring construction can suitably have a profile

which consists of a largely horizontal ring disc with four steps, of which step three is arranged on one side of the ring disc <p>g the fourth is arranged on the other side, with at least the two outer steps arranged on the same side and connected to the ends of the skirts and the other steps of the ring construction are connected to the wall of the container. The only step on one side of the ring disc can be arranged at the inner or outer ring disc edge or in the middle of this.

According to another embodiment, another ring disc is arranged between the ring disc and the skirt, which has two further steps for connection with the first ring disc's overlying step via connection strips.

In another variant, the ring construction consists of

three ring-shaped profiles arranged at a distance from each other which in cross-section form the corner points of a triangle and are connected

with each other by means of connecting elements, the profiles being designed with steps for connection with the connecting elements, the skirts and the container wall. In this case, the inner and outer profiles are arranged in the same plane. With such a design, the middle of the three profiles has a Y-shaped cross-section, the inclined step of which is directed towards the other two profiles and connected to them over the connecting elements, while the vertical step is connected to the inner skirt. The two shells that form the container can advantageously have different diameters and the gaps between the shells can be closed by means of one of the connecting elements at the same time that the inner and outer profiles of the ring structure have a step which is directed towards the edge of the adjacent shell, a further step which is directed towards the other profile in question, and a third step which is directed towards the corresponding step on the middle profile, and the outer profile has a fourth step which is directed towards the outer skirt.

In a further development of the invention, the inner profile has four steps, two of which are arranged opposite each other against the edges of the container wall and connected to them, while one of the other two steps is directed towards the outer profile and the other towards the middle profile, as the outer profile has three steps which are directed towards the inner profile, towards the outer skirt and towards the middle profile.

The ring structure can conveniently consist of four

spaced apart profiles that form the corner points of a rectangle; the upper and lower profiles then have a Y-shaped cross-section, the inclined steps of which are directed towards the neighboring profiles, while the corresponding vertical steps are directed outwards towards the edge of the upper bBholder shell or towards the inner skirt, while the other two profiles each have a third steps which are connected to the lower container shell and to the outer skirt respectively, and two of the diametrically opposed profiles each have a fourth step by means of which they are connected to each other over a connecting element.

Further features of the invention appear from the undBr requirements.

With such a support, the forces that act across the axis of the tank or parallel to the tank's deck and are in the form of shear stresses will be transferred over the ring structure to one or both skirts in the form of shear stresses. There will therefore, as a result of the interaction/between the ring structure and the tank jacket, due to transverse forces not be exceeded

fskörjæt rnspoeenn nibøngyeemr omferna terr ingpkå onsestlvre uktsajonnk^méan intteill e onp. plaOgveerreft ørvinigl a baarve spoon over the skirts which are designed as closed ring surfaces.

As for the forces acting parallel to the axis of the tank,

these are also transferred over the ring structure to the ship's storage above the skirts, one of which will be exposed to pressure and the other to tension. With this combined effect of the two skirts, the interaction between the ring structure and the tank jacket will, due to the forces acting on it. parallel to the axis of the tank, practically no bending moments are transferred to the tank shell, unlike those that would occur if only a single skirt were provided, where larger bending moments would occur as a result of the non-concentric line of attack of the reaction forces on the shell half surface.

Thermal contraction of the tank, which is quite exactly similar to that of the circumferential construction, since they are largely at the same temperature, is possible due to the presence of a temperature gradient in the two skirts and connecting parts, the temperature increasing from that edge " which is connected to the peripheral structure versus that connected to the ship's supporting structure. As the skirts lack stiffeners in the area closest to the periphery of the tank, which results in less stiffness compared to the peripheral structure, the entire supporting system will be thermally deformed, so that the peripheral construction will follow the tank jacket and will keep it essentially parallel to itself. This means that both the normal forces acting on the tank and the bending moments produced as a result of the thermal shrinkage will be small and the load... on the tank jacket in the vicinity of the midsection or equatorial section will be kept within moderate limits.

The invention shall be explained in more detail by means of examples with reference to the drawings, if fig. 1 schematically shows a vertical section of a spherical tank arranged on a support or carrying device made in accordance with the invention for installation on board a ship, fig. 2 shows on a larger scale a detail of the design according to fig. 1, fig. 3 shows a variant of the embodiment according to fig. 1, and fig. 4 shows in the same way as fig. 2 a detail of the embodiment according to fig. 3; fig. 5 shows a third embodiment and fig. 6 an associated detailed section, fig. 7 shows a modified embodiment similar to the embodiment according to fig. 2, 4 and 6, but where the circumferential support structure is formed by two or at least two profiles; fig. 8 schematically shows a diametrical section of a spherical tank placed on a support device according to the invention, fig. 9 shows in cross-section a detail of the embodiment according to fig. 8, fig. 10 and 11 show modified versions of the construction according to fig. 8 and fig. 12 shows schematically and in section another example of a device according to the invention.

The drawings show a largely spherical tank 1 with a peripheral support device which, for the sake of simplicity, below is called a ring carrier, ring disc or ring 2 and which is supported by two support and connection parts 3 respectively. 4 which is called skirt below and which surrounds the tank, but is arranged at a distance from each other in the radial direction; their upper edges are connected to the ring carrier 2, while their lower edges are in connection with a carrier foundation 5. The ring 2 is connected to the tank 1 in such a way that at least its inner circumference part forms part of the tank's mantle. With this device, forces that act perpendicular to the axis of rotation of the tank are absorbed by at least one of the skirts 3 and 4, while forces that act parallel to this axis are absorbed by both skirts, one being subjected to tension and the other for pressure without bending moments building up in the tank jacket. The skirts 3, 4

are continuous at least up to the ring carrier's 2 region,

and at least one of these skirts, preferably the one exposed to pressure, is continuous over its entire circumference.

Two stiffeners 30 are placed between the skirts 3 and 4 in the meridian plane of the tank 1 between the support foundation 5 and a support ring 31 located closer to the ring carrier 2 in a part of the skirts, where these are continuous. Between the ring 31 and the foundation 5, a further ring 32 can be arranged by a further stiffener 30 between the skirts 3 and 4. The upper parts of the skirts 3 and 4, together with the ring carrier 2 and the support ring 31, limit a circumferential space 26 for cables, such as cooling - center lines. With the embodiment according to fig. 1, the ring carrier 2 consists of a profile with an open shape which, according to fig. 2 has a continuous step 6 which preferably runs horizontally and which is equipped with a number of continuous flanges or ribs (called projections in the introduction) 7, 8, 9 and 10. There are three flanges 7, 8 and 9 which face downwards and one. flange 10 facing upwards. The flanges 9 and 10 extend from the inner edge of the step 6 and are directed in opposite directions towards the edges of the two halves 11 respectively. 12 of tank 1 and is welded together with these. The flanges 7 and 8 are welded together with the upper edges of the supports 3 and 4. Fig. 3 and 4 show a continuous flange 10 arranged at the outer edge of the step 6, so that it is flush with the outer downward-directed flange 7. While the flanges 9 and 1.0 in the embodiment according to fig. 1 and 2 are connected to the adjacent tank shell halves 11 and 12, the lower, inner flange 9 in the embodiment according to fig. 3 and 4 in connection with the lower half 11 of the tank jacket, while the upper, outer flange 10 is in connection with the upper half 12 of the tank jacket. In this case, it is not only the flanges 9 and 10 that form part of the tank jacket, while also the step 6 of the ring carrier 2. Therefore, the upper half 12 of the tank 1 is designed with a larger radius than the lower half 11. Fig. 5 and 6 show an embodiment , where the upper continuous flange 10 is arranged somewhere between the edge portions of the step 6, preferably directly opposite the intermediate lower flange 8 which is connected to the inner skirt 4. In this case, it is not only the flanges 9 and 10, but also the step portion between those that form part of the tank's 1 mantle.

The embodiment according to fig. 3 and 4 can be used for storage and transport of fluid at low pressure close to atmospheric pressure, while the design according to fig. 5 and 6 are suitable for use in connection with low and medium pressures; the embodiment according to fig.

1 and 2 are appropriate for low, medium and high pressures.

Fig. 7 shows an embodiment where the ring carrier comprises

two profiles with a shape similar to the shape of the profile according to fig. 1-6. The profiles are arranged at a distance from each other, thus

that their steps 6' and 6" run parallel. The upper profile has three downward-directed flanges 7', 8', 9' and one upward-directed,

inner flange 10', while the lower profile has a step 6" with three upwardly directed flanges 14, 13 and 10" and three downwardly directed flanges 7", 8" and 9". The upper profile's inner flange 10' is connected to the upper half of the tank 12, while the section's lower, inner flange 9' is connected to a mantle intermediate part 15 which is connected on the underside to the lower profile's inner, upper flange 10". This profile's downward inner flange 9" is connected to the tank's lower half 11. The lower profile's lower flanges 7" ag 8"

is, as explained above, connected to the skirts 3 and 4 upper edges. Between the upper profile's intermediate lower flange 8' and the lower profile's intermediate upper flange 13, an intermediate piece 14 is arranged, and a corresponding piece .16 between the upper profile's outer, lower flange 7' and the lower profile's outer, upper flange 14. In this way, the skirts 3 and 4 are extended all the way up to the upper ring profile with the step 6'. This profile's upper flange 10' can also be arranged in another place of the step,

as previously shown in fig. 3 and 5.

l/ed consideration of fig. 7 it will be seen that it is

possible to make the ring carrier with even more ring profiles than the two shown in the figure.

fig. 8 schematically shows a tank 1 with a ring carrier of another design with the details shown in fig. 9. In this embodiment, the ring carrier comprises three continuous profiles IB,

19, 20 which all extend concentrically to the tank jacket and are parallel to each other. Two of these profiles 18 and 19 lie in the same horizontal plane, while the profile 20 is arranged on the underside of and between the two profiles 18 and 19. The profile 18 has, on the side which is designed to form part of the tank jacket, an upward and a downward facing flange, one of which is to be connected to the tank's lower half 11 and the upper one to the tank jacket's upper half 12. Furthermore, the profile 18 has a horizontally outwardly directed flange and an inclined downwards and outwardly directed flange. The profile 19 has an inwardly directed flange which is connected to the profile's flange by means of an intermediate ring disc or a number of ring disc parts 21

18 horizontally outward-facing flange. Furthermore, the profile has 19

a downward facing flange connection with the outer skirt of the tank 3

and an obliquely downward and inwardly directed flange. Profiles' 18

and 19 on oblique downward-directed flanges are above two intermediate pieces 21

connected to the third profile 20 which has a Y-shaped cross-section and whose obliquely upwards-directed arms or flanges are connected to the intermediate pieces 21 which are cone segments or parts of corresponding turning bodies. The downward-facing flange or stem of the profile 20 is connected to the inner skirt 4 of the tank.

The embodiment according to fig. 10 certainly resembles the embodiment according to fig. 9, except that the profiles IB and 19 are not in the same plane, as the outer ring profile 19 is lower than the meridian plane of the tank and the profile 18. In this case, the skirts 3 and 4 are also not made with a rectilinear radial cross-section, i.e. that they are not consists of cylinder segments or parts of such, but of a combination of cylinder segments and cone segments.

The embodiment in fig. 11 largely corresponds to the one on

fig. 9, but the upper tank jacket half 12 in this case has a larger diameter than the lower half 11, so that it rests on the ring carrier 2 directly above the outer skirt 3. The design is thus analogous to that in fig. 3 and 4. In this case, the upper flange of the outer profile 18 and the flange facing the cylinder form part of the tank jacket, and the same applies to the upper part and the inner part of the profile 19. The connecting part 21 between the profiles 18 and 19 is continuous and forms part of the tank jacket. The difference between the execution according to

fig. 9 and the one according to fig. 11 largely consists in that the tank jacket wall 11 and the support 3 in fig. 9 has changed places and that the horizontal intermediate part 21 between the profiles 18 and 19 is continuous.

Fig. 12 shows yet another embodiment of the support device according to the invention. Besides the three ring profiles

25. same plan, but this need not be the case. The profiles 23 and 25 can optionally be arranged opposite each other, while fig. 12 shows them mutually offset in the radial direction. The profiles 23 and 25 have a largely Y-shaped cross-section with their two flanges halfway directed towards each other and the third flanges directed away from each other. The lower flange of the profile 25 is connected to the skirt 4 and the upper/right flange of the profile 23 is connected to the tank part's upper half 12, which has a larger radius than the lower tank part 11. The profile 24 has a downward-facing flange which is connected to the tank jacket's lower half 11, one on obliquely outwardly directed flange which is connected over an intermediate part to the corresponding flange of the profile 23, and a horizontally outwardly directed flange which is connected to a corresponding horizontal flange on the outer ring profile 22. The outwardly, obliquely downwardly directed flange of the profile 24 is over an intermediate part connected to a inward, obliquely upwardly directed flange on the ring profile 25, whose lower flange is connected to the skirt 4. The outer ring profile 22 has a downwardly directed flange that is connected to the skirt 3, an obliquely inwardly directed flange for connection with the profile 25, an obliquely upward flange for connection with the profile 23 and a horizontally oriented flange for connection with the profile 24. The ring carrier structure can be stiffened by radial walls 21'.

1 all shown and explained case lies the skirts

3 and 4 and the supporting foundation 5 on the underside of the tank's equatorial or central plane, so that the entire construction rests on the foundation 5. There is, however, nothing to prevent the support device from being designed as a suspended device, i.e. that the skirts 3 and 4 are suspended up into a suspended foundation. This device appears when you turn all figures face down. The force effect on the skirts 3 and 4 and the foundation 5 will then be reversed, but the construction remains the same. V/ed to make the skirts 3 and 4 continuous at least in the area between the ring carrier 2 and the one ring 31, as shown in fig. 1 and 2, there arises a channel 26 between the skirts mentioned above and which can be used for the introduction of a cooling fluid for pre-cooling the tank and the ring carrier before the liquid itself is introduced into the tank. With the embodiment according to fig. 7, such a channel 26 can be formed between the steps 6" and 6' and the intermediate skirt parts 16 and 17. There can also be arranged a ring below the step 6" between the skirts 3 and 4 to form a channel as in Fig. 1. With the design according to Fig. 8, a channel 26 can be formed by the fact that the ring carrier 2 itself is designed closed. Optionally, a ring (not shown) can be arranged between the skirts 3 and 4 on the underside of the ring carrier 2. The channel 26 must naturally - must be equipped with openings for the inlet and outlet of the refrigerant.

Claims (14)

Support device for a container in the form of a rotating body with a vertical axis for installation on board a ship, consisting of an annular structure (2) which is arranged between the upper D and the lower container shell and is supported by a circumferential skirt which is rigidly and continuously connected to the structure and surrounds the lower container shell at a distance, characterized in that to avoid distortions of the ring structure (2) as a result of the skirt (4) which attacks at a distance from the ring structure, a further skirt (3) is attached which surrounding the first skirt (2) concentrically with intermediate spacing. 2. Device according to claim 1, c h a r a c t e r i s — characterized in that the ring structure (2) has a profile consisting of a largely horizontal ring disc (6, 6') with four steps (7, 8, 9, 10; 7', 8', 9', 10'), of which steps three (7, 8, 9; 7', B', 9') are arranged on one side of the ring disc 6; 6') and the fourth (10; 10') is arranged on the other side, with at least the two outer steps (7, 8; 7', 8') being arranged on the same side and connected to the ends of the skirts (3, 4) and the ring structure's other steps (9, ID; 9', 10') are connected to the wall of the container (1). 3. Device according to claim 2, characterized in that the only step (10; 10') on one side of the ring disc (6; 6') is arranged at the inner ring disc edge (fig. 2, 7). 4. Device according to claim 2, characterized in that the first step (10) on one side of the ring disc (6) is arranged at the outer ring disc edge (fig. 4). Device according to claim 2, characterized in that the only step (10) on one side of the ring disc (6) is arranged on its middle part (fig. 6). 6. Device according to claim 2, characterized in that between the ring disc (6') and the squiggles (3, 4) another ring disc (6") is arranged which has two further steps (13, 14) for connection with the first ring disc (6') overlying steps (7<1>, 8') over connection strips (16, 17) (fig. 7). 7. Device according to claim 1, characterized in that the ring structure (2) consists of three ring-shaped profiles (18, 19, 20) arranged at a distance from each other, which in cross-section form the corner points of a triangle and are connected to each other by means of connecting elements (21), the profiles (18, 19, 20) being designed with steps for connection with the connection elements (21, the skirts (3, 4) and the container wall (fig. 9, 10, 11). 8. Device according to claim 7, characterized in that the inner and outer profiles (18, 19) are: arranged in the same plane. 9. Device according to claim 7 or 8, characterized in that the middle (20) of the three profiles 19, 20) has a Y-shaped cross-section, the inclined step of which is directed towards the other two profiles (18, 19) and connected with these over the connecting elements (21), while the vertical step is connected to the inner skirt (4). 10. Device according to claim 7 or B, characterized in that the two shells (11, 12) which form the container (l) have different diameters and the gap between the shells is closed by means of one of the connecting elements (21), that the ring structure (2) inner and outer profiles (18, 19) have a step which is directed towards the edge of the adjacent shell, a further step which is directed towards the relevant other profile (18 and 19 respectively), and a third step which is directed towards the corresponding step on the middle profile (.20) and that the outer profile (19) has a fourth step which is directed towards the outer skirt (3). 11. Device according to claim .7 or 8, characterized in that the inner profile (18) has four steps, two of which are arranged opposite each other against . the edges of the container wall and connected to these, that one of the other two steps is directed towards the outer profile (19) and the other towards the middle profile (20), the outer profile (19) having three steps which are directed towards the inner profile (18), towards the outer skirt (3) and towards the middle profile (20). 12. Device according to claim 1, characterized in that the ring construction consists of four spaced apart profiles (22, 23, 24, 25) which form r . the corner points in a rectangle, that the upper (23) and the lower profile (25) have a Y-shaped cross-section, the inclined steps of which are directed towards the neighboring profiles (22, 24), while the respective vertical steps are directed outwards towards the upper container shell ( 12) edge respectively towards the inner skirt (4), that the two other profiles (22, 24) each have a third step which is connected to the lower container shell (11) respectively to the outer skirt (3), and that two of the diametrically opposed profiles each have a fourth step at the aid of which they are connected to each other via a connecting element (21). 13. Device according to claims 1 12, characterized in that the ring discs (6; 6', 6") or profiles (18, 19, 20; 22, 23 24, 25) which form the ring structure (2), together with the further structural elements (3, 4; 16, 17; 21; 21'; 31) enclose a conduit (26) which is provided with inlet and outlet for a refrigerant. 14. Device according to claim 13, characterized in that the wiring channel (26) is limited by the ring construction (2), the skirts (3, 4) and a ring mixer (31) which is arranged between the skirts (3, 4) (fig. 1).