US3800970A

US3800970A - Integrated tank containers for the bulk storage of liquids

Info

Publication number: US3800970A
Application number: US00121976A
Authority: US
Inventors: R Jackson
Original assignee: Conch International Methane Ltd
Current assignee: Conch International Methane Ltd
Priority date: 1970-03-19
Filing date: 1971-03-08
Publication date: 1974-04-02
Anticipated expiration: 1991-04-02
Also published as: NL7103601A; DE2112900C3; SE373650B; FI53952C; GB1302214A; FI53952B; ES389308A1; DE2112900B2; BE764378A; DE2112900A1; JPS5652474Y2; NO127771B; MTP686B; JPS54146409U; PL76330B1; SU361555A3; CA946301A; FR2087783A5

Abstract

An integrated membrane-type tank container for cryogenic liquids, supported within a rigid outer shell, is made up of a multiplicity of panels in the form of shallow boxes of thin, flexible metal sheet material filled with load-bearing insulation, and sealingly connected together by edge extensions of their front and back faces respectively to provide inner and outer impervious membrane walls, which walls are attached to a support framework carried by the rigid outer shell. The edge extensions of adjacent panels are welded together through metal strips folded to provide expansion joints and the shallow boxes are attached to the framework through these strips. The framework is provided with brackets for adjusting the spacing of individual frame members from the outer rigid shell to facilitate even alignment of the shallow boxes.

Description

United States Patent [1 1 Jackson Apr. 2, 1974 [54] INTEGRATED TANK CONTAINERS FOR 3,302,358 2/1967 Jackson 220 9 LG x THE BULK STORAGE 0F LIQUIDS 3,341,049 9/1967 Forman et al. l l4l74 A X 3,547,302 l2/l970 Jackson l'l4/74 A X [75] Inventor: Robert G. Jackson, I-Iornchurch,

England FOREIGN PATENTS OR APPLICATIONS l 7163 G B" ..2209LG [73] Assignee: Conch International Methane 93258 9 real mam I Llmned Nassau Bahamas Primary Examiner-Herbert F. Ross [22] Filed: Mar. 8, 1971 Assistant Examiner-Stephen Marcus 1 pp No: 121,976 Attorney, Agent, or FzrmMax L. Llbman o [57] ABSTRACT [30] Foreign Apphcat'ml Priority Data An integrated membrane-type tank container for cryo- Mar. 19, 1970 Great Bmam 13247/70 genie liquids Supported within a rigid outer She, is

made up of a multiplicity of panels in the form of shal- [52] 220/9 LG, 220/10 220/15 low boxes of thin, flexible metal sheet material filled [51] Int. CL, B65d 25/18 with loadbearing insulation, a sicalingly connected [58] Fleld Search 220,9 9 together by edge extensions of their front and back 114/74 A faces respectively to provide inner and outer impervious membrane walls, which walls are attached to a [56] References cued support framework carried by the rigid outer shell.

UNITED STATES PATENTS The edge extensions of adjacent panels are welded to- 3,15o,793 9/1964 Messer 220 9 F gather through metal Strips folded to Provide p 2,744,042 5/1956 Pace 2220/) F sion joints and the shallow boxes are attached to the 2,896,271 7/1959 Kloote et al 220/9 F framework through these strips. The framework is 7 4 H1 L r x 2 LG provided with brackets for adjusting the spacing of ingoctfrellui... dividual frame members from the outer rigid shell to g yeta 3,150,794 9/1964 Schlumberger et al. 220 9 LG facfl'tate ahgnnlem of the Shallow bDXes' 3,298,345 1/1967 Pratt 220/15 X 3 Claims, 3 Drawing Figures PATENTEDAPR 21914 3.800.970

' sum 1 0F 3 lnvenlor Robe/7' G Jbc K5011 M74 Attorney Inventor Roberf G Jae/@5014 44 4 Attorney PATENTEDAPR 2mm SL800 9 70 SHEEI3UF3 Inventor INTEGRATED TANK CONTAINERS FOR THE BULK STORAGE OF LIQUIDS This invention relates to integrated tank containers for the bulk storage or transport of liquids at temperatures greatly differing from ambient temperature. The invention is primarily intended for containers for cold liquids such as liquefied gas, e.g., natural gas, and petroleum gas, but it may also be applicable to containers for housing warm liquids.

An integrated tank container comprises essentially a housing of load-bearing thermal insulation supported within an outer rigid sheel and lined internally with a thin and flexible fluid-tight membrane (hereinafter referred to as a primary membrane) of sheet material, e.g., in the case of liquefied gas, a metal which is not subject to cold embrittlement, the primary membrane being supported against internal loads due to hydrostatic pressures and inertia forces by the surrounding thermal insulation. The invention is particularly concerned with an integratedtank container. of the kind including a further or a secondary membrane similar to the primary membrane which surrounds the housing of load-bearing thermal insulation.

It is normal practice to assemble such containers from within the space to be enclosed by said container and this is usually achieved by completing the construction of each layer, i.e., the two membranes and the load-bearing thermal insulation, in turn starting from the outermost layer. This practice is very timeconsuming and costly since it requires a high standard of accuracy inaligning and assembling the component parts of each layer at site. These component parts may comprise, for example, sheets or panels for the membranes, and solid insulation panels, or boxes made of solid insulation material filled with loose granular insulation material, for the load-bearing thermal insulation.

Also with a container of this kind it is usually necessary I plicity ofprefabricated relatively shallow boxes of a suitable thin and flexible sheet material, which boxes are sealingly connected together around their side walls, said walls are attached to a support framework carried by the outer rigid shell, and said housing is provided by fillings of load-bearing insulation material contained within said boxes.

Where the container is substantially plane-faced, preferably those boxes providing the plane-faced portions contain fillings of load-bearing thermal insulation, the corner portions of the container being provided by curved boxes which contain fillings of thermal insulation material which is of a loose or resilient nature.

The side walls of the boxes may include edge portions of at least the faces providing the secondary membrane which extend beyond said side walls in which case, a set of connecting members is attached to the support framework for sealing together co-operating edge portions of these faces, a further set of connecting members is provided for sealing together the faces providing the primary membrane, and each space defined between the two sets of connecting members and the side walls of adjacent boxes contains a further filling of said insulation.

Conveniently the further set of connecting members for the primary membrane may be carried on the inner faces of said further fillings of insulation.

Said sealing between the faces may be effected in accordance with a method described in co-pending U.S. Patent Application by Robert G. Jackson and Edward Armstrong for Methods of Welding Together Sheets to Form Walls, Tanks or the Like in which, for example, use is made of sets of connecting members of generally T-shaped cross-section. With connecting members of such cross-section the further fillings of thermal insulation are preferably formed with slots which embrace the stems of the set of connecting members for the secondary membrane to locate said further fillings in position.

The prefabricated boxes may be evacuated and/or purged with an inert gas during their construction.

Thesupport framework may be attached to the outer rigid shell via brackets which provide for adjustment of the spacing of the frame members of said framework from the outer rigid shell. Such an arrangement facilitates the even alignment of the support faces of the frame members should any undulations be present in the outer rigid shell.

It will be appreciated that because the boxes with their fillings are prefabricated and provide the two membranes and the housing of thermal insulation, the amount of site alignment and assembly is reduced considerably, a high standard of accuracy being required only for the initial alignment of the boxes on the support framework.

In order that the invention may be readily understood one. embodiment thereof will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a section through part of the container;

FIG. 2 is an enlarged sectional view of a corner of the container; and

FIG. 3 is an enlarged'fragmentary perspective view of a detail of the container.

Referring to FIGS. 1 and 2, the container is of planefaced form and comprises a primary membrane 1 which lines a housing 2 of load-bearing thermal insulation, a secondary membrane 3 extending around the housing 2 and attached to an outer rigid shell 4 via hardwood frame members 5 which are arranged to provide a rectangular lattice framework. In this embodiment the housing 2 except at its corners comprises balsa wood panels 6 and the primary and secondary members 1, 3 are of an iron-nickel alloy having a very low co-efficient of expansion; a suitable alloy is that sold under the Registered Trademark INVAR.

In accordance with the invention the primary and secondary membranes 1, 3 of the plane-faced portions of the container are provided by the two sets of

faces

7, 8 respectively (see FIG. 2) of a multiplicity of shallow boxes 9 which are welded together, the balsa wood panels 6 of the housing 2 providing fillings for these boxes. The faces 8 of the boxes 9 have peripheral edge portions which extend beyond the sides 10 of their boxes so that each box may be aligned over an opening of the lattice framework with its extended edge portions 1 1 overlapping the frame members 5. The support faces'of the frame members have attached thereto connecting members 12 which are formed by folding strips of INVAR (Registered Trademark) and are of generally T-shaped cross-sectior'1. The arms 13 of each connecting member are extended a short distance around the sides of their frame member for attachment to the latter. The stem 14 of each connecting member is enlarged at its free end as shown at 15 to provide a rail on which a welding machine (not shown) may be mounted for welding the edge portions 11 of its respectween the side walls of adjacent boxes is filled with a further panel 16 of balsa wood, this panel being provided with a slot 17 for clipping onto the rail of said connecting member. The inner face of each further panel 16 has attached thereto a further connecting member 19, similar to the connecting member 12, the arms 20 of which, with the panel 16 in its located position, extend across the faces 7 of their respective pair of boxes 9. The arms 20 are then welded to their respective faces 7 by the method referred to hereinbefore with respect to the connecting member 12. g

The rectangular lattice framework provides openings of regular size over most of the area of the plane-faced portions of the container and hence the boxes 9 for those openings are of a standard size. The dimensions of the container may be chosen such that said planefaced portions are assembled complete from standard boses 9. However, it will be appreciated that where the dimensions are not so chosen further boxes of suitable dimensions, for example such as shown at 9a in FIG. 1, may be used in conjunction with the standard size boxes.

Each frame member 5 is supported at spaced positions in metal cradles 21, preferably of 9% nickel-steel,

which in turn are attached to hardwood blocks 22. Further metal cradles 23, also of 9% mickel-steel, are attached to the outer rigid shell 4 and embrace each hardwood block 22. The walls of each cradle 23 are provided with slots 24 (see FIG. 3) through which bolts 22a (FIG. 2) may pass and through apertures (not shown) extending through the respective hardwood block 22. Thus, the spacing between the support face' of each frame member 5 and the outer rigid shell 4 may be adjusted within the limits of the slots 24 of the cradles 23 wherebythe support faces of all of the frame members 5 may be aligned to provide an even surface on which the boxes 9 are located. Each

cradle

21, 23 is provided with a 'pair of

thin webs

25, 26 respectively of 9% nickel-steel arranged to be welded together once the spacing of the frame members 5 from the outer rigid shell 4 is set.

- Where the frame members 5 of the framework intersect, the support arrangement therefor includes a metal cradle 27-which is of cruciform shape (see FIG. 3).

I Otherwise the support arrangement is similar to that described above.

The corners of the container are provided by further prefabricated boxes 28 similar to the boxes 9. However, the boxes 28 are curved, i.e., in the case ofa dihedral comer they are radiussed as shown in FIG. 2 and in the case of a trihedral corner they are part spherical. Also these boxes contain a filling of loose or resilient non-load-bearing thermal insulation, e.g., a mineral wool, thus permitting the boxes to flex and deform depending upon the stresses and loads to which they are subjected in use.

Preferably, the connection between each frame member 5 and its connecting member 12 is strengthened, particularly adjacent the corners of the container by welding the edges of the horizontal 13 of the connecting member to the metal cradles 21.

It will be appreciated that the arrangement described above for welding the

boxes

9, 28 together is such, with the balsa wood panels 6 and 16 being constrained by the side walls 10 of the boxes 9, that said panels act as keys to maintain the faces 7 of the plane-faced portions of the container substantially in their relative positions.

However, particularly at the corners of the container, should excessive stresses or loads be induced in use, the resilience of the walls IOmay permit some movement of the boxes 9 to take place thus permitting the corner boxes 28 to deform. Such movement of the boxes 9 may be increased by providing inserts within the boxes 9 of, for example, compressed wool between the edges of the fillings 6 and their respective sides 10 of said boxes. Furthermore, a copper strip may be provided within the

boxes

9, 28 adjacent to those parts of the faces 7 to which the connecting members 19 are to be welded, said copper strips thus providing a heat sink during the welding process.

If required, secondary frame members 29 (see FIG. 1) may be provided located between the frame members 5 to provide additional support for the boxes 9 and the support arrangement for the frame members 29 may be the same as that described for the frame members 5. The frame members 29 would not carry connecting members 12. With such an arrangement the space 30 between the

boxes

9, 28 and the outer rigid shell 4 may be filled with a loose thermal insulation material such as mineral wool, or granular material such as that sold under the Registered Trademark PER- LITE. Alternatively, the space 30 may be provided with a load-bearing thermal insulation system, which may comprise, for example, a two-part insulation system similar to that described in my co-pending US. Pat. application Ser. No. 801,495, particularly with reference to FIG. 4. Thus, the two-part insulation system may comprise a framework of solid insulation panels, e.g., balsa wood, defining areas containing rigid foamed plastics material, e.g., polyurethane. With this alternative arrangement the additional frame members 29 would not be required since the boxes 9 would be supported against the inner faces of the two-part insulation system.

The container construction as hereinbefore described includes the following advantages when compared with a construction in which the membranes and load-bearing thermal insulation are built up in layers:

pletely, the boxes 9 and 28' may each be of uniform size.

iii. Due to their prefabrication away from the site, for safety reasons, the

boxes

9 and 28 may be purged of air with an inert gas such as nitrogen or carbon dioxide. Alternatively the air may be evacuatedin which case the insulation properties of the boxes may be improved. Preferably these operations would be carried out through the side walls 10 of the boxes.

iv. The primary membrane 1 is rigidly tied to the frame members 5 via the sides 10 of the

boxes

9, 28. Although the sides 10 provide heat paths through the housing 2 of thermal insulation, the effect of these heat paths is minimized by the thinness of the membrane material.

v. Because the fillings of thermal insulation are contained completely within the

boxes

9, 28, should the primary membrane 1 be punctured in use, any damage occurring is localized.

vi. Because the secondary membrane 3 is tied to the primary membrane 1 via the side walls 10 of the

boxes

9, 28, a further housing of load-bearing thermal insulation for supporting the second membrane is not essential.

vii. Because each plane-faced portion of the container provided by the boxes 9 is independent of each of its adjacent wall portions due to said boxes being mounted directly on the framemembers 5, the corner boxes 28 may be of any desirable shape to fill the corner spaces between adjacent plane wall portions; additional support for the out of balance loads on the frame members 5 immediately adjacent the corners may be conveniently provided by suitable ties or the like between the outer rigid shell 4 and said frame members.

It will be appreciated that the fillings 6, 16 may be of any suitable load-bearing thermal insulation material, and preferably the material will have a relatively low co-efficient of expansion as is the case with balsa wood which varies beween approximately 2 to 8 X l0' unit/unit/F. depending upon the direction of the grain. However, it may be that materials having a significantly higher co-efficient of expansion could be used. One such material is polyurethane foam which has a co-efficient of approzimately 50 X unit/unit/F. and the panels to fit within and between the boxes 9 would be built up from one or moresprayed layers of foam with prehaps re-inforcement netting between at least some of the layers to cater for the significant decrease in overall dimensions of the panels which would inevitably take place on cooldown of the container to the temperature of the liquefied gas, e.g., --l6l C. for LNG, compressed fibreglass or like fibrous material would be inserted between the edges of the panels and the sides 10 of the boxes. Also in order to reduce the tendency of these panels to bow at the liquefied gas temperature as a result of the large temperature gradicat which would be present across the thickness of the panels, said panels may be ofa honecomb construction, for example, as described in our British Pat. No. 932,58 1, the spaces'in the honeycomb being filled with the polyurethane foam. With the present invention it will be appreciated that the fluid impervious inner and outer sheet described in that specification as being bonded to the faces of the panel will not be required since their function is taken by the

faces

7, 8 of the boxes 9. However, as a result of the appreciable contraction that would take place in the panels, these panels may not be so effective as balsa wood panels for acting as keys to maintain the positions of the. faces 7 of the plane-faced portions of the boxes as discussed here inbefore.

I claim:

1. a. An integrated tank container for the bulk storage or transport of liquids at temperatures greatly differing from ambient temperature,

b. 'said container comprising a housing of loadbearing thermal insulation supported within an outer rigid shell, said housing being built up of fluid-tight closed shallow boxes made of flexible sheet material and filled with load-bearing insulation material, said boxes being set in spaced edge to-edge alignment to form said housing,

c. said shallow boxes each having two generally parallel opposed main wall faces of large area, one being a front face and disposed toward the inside of the tank, the other being a back face, said wall faces being spaced from each other by relatively narrow continuous side wall members,

(1. said back faces of the respective boxes having peripheral edge portions extending out in the plane of the back faces beyond the side wall members,

e. said extended portions of the back faces being attached to a support framework carried by the outer rigid shell, and to each other in liquid-tight fashion to provide a secondary membrane,

f. said front faces having peripheral edge portions extending out beyond said side wall members, said extended portions of the front faces being attached to each other in liquid-tight fashion to provide a primary membrane,

g. the sides of said container being substantially plane-faced, I

h. where those boxes providing the plane-faced portions contain fillings of said load-bearing thermal insulation,

i. the corner portions of the container being provided by curved boxes which contain fillings of thermal insulation material which is of a loose or resilient nature,

j. wherein the walls of the boxes include said peripheral edge portions providing the secondary membrane extending beyond said boxes,

k. a set of connecting members attached to the support framework for sealing together adjacent edge portions,

l. a further set of connecting members for scaling together the faces providing the primary membrane,

m. each space defined between the two sets of connecting members and the adjacent boxes containing a further filling of load-bearing insulation material,

n. wherein each member of the two sets of connecting members is of generally T-shaped cross-section,

o. and .sealing between the faces to provide the primary and secondary membranes is effected by the arms of the respective members being welded to said faces.

2. A container according to claim 1,

p. wherein said further fillings are rigid, elongated members formed with slots which embrace the stems of the set of connecting members for the secondary membrane to locate said further fillings in position.

- 3,800,970 7 I 1 8 3. a. An integrated tank container for the bulk storextended portions of the front faces being attached age or transport of liquids at temperatures greatly difto each other in liquid-tight fashion to provide a fering from ambient temperature, primary membrane,

b. said container comprising a housing of loadbearing thermal insulation supported within an g. wherein the walls of the boxes include said peripheral edge portions providing the secondary memouter rigid shell, said housing being built up of brane extending beyond Said boxes fluid-tight closed Shallow {30x85 made P flexlble h. a set of connecting members attached to the supiheet gt ggl sgz d b l lz s ggi rg ggt gs szzzgglz g z' port framework for sealing together adjacent edge I portions, ahgnment to saild housmg l] 10 i. a further set of connecting members for sealing to- 53:? iziigg g i sgfi zi gz ifg f 2: I ether the faces Providing the Primary membrane, being a from face and disposed toward the.mS1de j. each space defined between the two sets of conof the tank, the other being a back face, said wall b d th adace t boxes contaim faces being spaced from each other by relatively P mg mem an 8 J narrow continuous side wall members mg a further filling of load-beanng insulation mated. said back faces of the respective boxes having peripheral edge portions extending out in the plane of k' wherem h member of the two Sets of connect' the back faces beyond the side wall members, mg members 15 Ofgenerany p cross'secnon, e. said extended portions of the back faces being attached to a support framework carried by the outer and Sealing between the faces Pmvlde the P rigid shell, and to each other in liquid-tight fashion mary and secondary membranes is effected by the to provide a secondary membrane, arms of the respective members being welded to f. said front faces having peripheral edge portions exsaid faces.

tending out beyond said side wall members, said

Claims

1. A. An integrated tank container for the bulk storage or transport of liquids at temperatures greatly differing from ambient temperature, b. said container comprising a housing of load-bearing thermal insulation supported within an outer rigid shell, said housing being built up of fluid-tight closed shallow boxes made of flexible sheet material and filled with load-bearing insulation material, said boxes being set in spaced edge-to-edge alignment to form said housing, c. said shallow boxes each having two generally parallel opposed main wall faces of large area, one being a front face and disposed toward the inside of the tank, the other being a back face, said wall faces being spaced from each other by relatively narrow continuous side wall members, d. said back faces of the respective boxes having peripheral edge portions extending out in the plane of the back faces beyond the side wall members, e. said extended portions of the back faces being attached to a support framework carried by the outer rigid shell, and to each other in liquid-tiGht fashion to provide a secondary membrane, f. said front faces having peripheral edge portions extending out beyond said side wall members, said extended portions of the front faces being attached to each other in liquid-tight fashion to provide a primary membrane, g. the sides of said container being substantially plane-faced, h. wherein those boxes providing the plane-faced portions contain fillings of said load-bearing thermal insulation, i. the corner portions of the container being provided by curved boxes which contain fillings of thermal insulation material which is of a loose or resilient nature, j. wherein the walls of the boxes include said peripheral edge portions providing the secondary membrane extending beyond said boxes, k. a set of connecting members attached to the support framework for sealing together adjacent edge portions, l. a further set of connecting members for sealing together the faces providing the primary membrane, m. each space defined between the two sets of connecting members and the adjacent boxes containing a further filling of loadbearing insulation material, n. wherein each member of the two sets of connecting members is of generally T-shaped cross-section, o. and sealing between the faces to provide the primary and secondary membranes is effected by the arms of the respective members being welded to said faces.

2. A container according to claim 1, p. wherein said further fillings are rigid, elongated members formed with slots which embrace the stems of the set of connecting members for the secondary membrane to locate said further fillings in position.

3. a. An integrated tank container for the bulk storage or transport of liquids at temperatures greatly differing from ambient temperature, b. said container comprising a housing of load-bearing thermal insulation supported within an outer rigid shell, said housing being built up of fluid-tight closed shallow boxes made of flexible sheet material and filled with load-bearing insulation material, said boxes being set in spaced edge-to-edge alignment to form said housing, c. said shallow boxes each having two generally parallel opposed main wall faces of large area, one being a front face and disposed toward the inside of the tank, the other being a back face, said wall faces being spaced from each other by relatively narrow continuous side wall members, d. said back faces of the respective boxes having peripheral edge portions extending out in the plane of the back faces beyond the side wall members, e. said extended portions of the back faces being attached to a support framework carried by the outer rigid shell, and to each other in liquid-tight fashion to provide a secondary membrane, f. said front faces having peripheral edge portions extending out beyond said side wall members, said extended portions of the front faces being attached to each other in liquid-tight fashion to provide a primary membrane, g. wherein the walls of the boxes include said peripheral edge portions providing the secondary membrane extending beyond said boxes, h. a set of connecting members attached to the support framework for sealing together adjacent edge portions, i. a further set of connecting members for sealing together the faces providing the primary membrane, j. each space defined between the two sets of connecting members and the adjacent boxes containing a further filling of load-bearing insulation material, k. wherein each member of the two sets of connecting members is of generally T-shaped cross-section, l. and sealing between the faces to provide the primary and secondary membranes is effected by the arms of the respective members being welded to said faces.