# US 8,091,494 B2 · Liquefied gas tank with a central hub in the bottom structure

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- Number: US 8,091,494 B2
- Document ID: US8091494B2
- Status: Granted
- Kind: B2
- Application number: 12/314,030
- Filed: 2008-12-03
- Published: 2009-08-13
- Granted: 2012-01-10
- Earliest claimed: 2007-12-03
- Assignees: NLI Innovation AS
- Inventors: Carsten Stanley Nikolajsen; Hans Hakon Norr
- Web page: https://patentgrep.com/patent/US8091494B2

## CPC

- B63B 25/16: heat-insulated (insulating panelling B63B3/68; heating or cooling B63J)
- F17C 13/082: {for large sea-borne storage vessels (load-accommodating arrangements for ships or waterborne vessels B63B25/12)}
- F17C 2201/0119: with flat end-piece
- F17C 2201/0157: Polygonal
- F17C 2201/032: with substantially vertical main axis
- F17C 2201/054: medium (>1 m3)
- F17C 2201/056: Small (<1 m3)
- F17C 2203/012: on or in the wall, e.g. ribs
- F17C 2203/0604: Liners
- F17C 2203/0665: radially wound
- F17C 2203/0678: Concrete
- F17C 2205/0119: Vessel walls form part of another structure
- F17C 2205/018: Supporting feet
- F17C 2205/0192: with external bearing means
- F17C 2205/0323: Valves
- F17C 2209/2154: Winding
- F17C 2209/221: Welding
- F17C 2209/232: of walls
- F17C 2221/013: Carbon dioxide
- F17C 2221/014: Nitrogen
- F17C 2221/033: Methane, e.g. natural gas, CNG, LNG, GNL, GNC, PLNG
- F17C 2221/035: Propane butane, e.g. LPG, GPL
- F17C 2223/0161: cryogenic, e.g. LNG, GNL, PLNG
- F17C 2223/033: Small pressure, e.g. for liquefied gas
- F17C 2223/038: Subatmospheric pressure
- F17C 2227/0135: Pumps
- F17C 2227/0178: in the vessel
- F17C 2260/011: Improving strength
- F17C 2260/016: Preventing slosh
- F17C 2260/036: Avoiding leaks
- F17C 2270/0105: Ships
- F17C 2270/0113: floating
- F17C 2270/0115: immerged
- Y10T 29/49826: Assembling or joining
- B63B: SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING (arrangements of vessel ventilation, heating, cooling, or air-conditioning B63J2/00; floating substructures as supports of dredgers or soil-shifting machines E02F9/06)
- 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 (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00; construction or assembling of bulk storage containers employing civil-engineering techniques E04H7/00; variable-capacity gas-holders F17B; liquefaction or refrigeration machines, plants, or systems F25)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention comprises a tank for liquefied gases or a so-called cryogenic tank (1) with a tank bottom structure (10) and a tank wall structure (11) arranged around a circumference of the tank bottom structure (10). The tank bottom structure (10) is provided with a tank bottom hub (2) adapted for being held by a bottom hub retainer (20) on a tank support structural floor (23). The tank is simple to install, cheap in production and handles in an improved manner forces acting upon it.

## Claims

### Claim 1

A cryogenic tank (1) for liquefied gas with a planar tank bottom structure (10) supporting a tank wall structure (11), comprising
a central single point hub (2) in said planar tank bottom structure (10), said central single point hub (2) having a substantially smaller diameter than a diameter of said tank bottom structure (10), said central single point hub (2) adapted for being retained by a corresponding hub retainer (20) on a tank support structural floor (23), said hub retainer (20) generally providing radially directed retention forces to said central single point hub (2) in the plane of said planar tank bottom structure (10) both when said cryogenic tank (1) is operating at cryogenic temperatures and when empty at ambient temperature.

### Claim 2 (depends on 1)

The cryogenic tank (1) of claim 1, said central single point hub (2) coupled to radial structural beams (3) further arranged for supporting said tank wall structure (11).

### Claim 3 (depends on 2)

The cryogenic tank (1) of claim 2, said radial beams (3) being prevented from vertical movement by vertical retainers (4).

### Claim 4 (depends on 2)

The cryogenic tank (1) of claim 2, said tank wall structure (11) comprising girders (12) extending from near outer ends of said radial beams (3), said girders (12) directed generally parallel to a vertical tank axis (9).

### Claim 5 (depends on 4)

The cryogenic tank (1) of claim 4, said beams (3) supporting a tank bottom liner (131).

### Claim 6 (depends on 1)

The cryogenic tank (1) of claim 1, said tank wall structure (11) extending from and around a circumference (15) of said planar tank bottom structure (10), said tank wall structure (11) arranged for being retained from lifting by rolling and/or pitching movement away from said tank support structural floor (23) by vertical direction retainers (4) arranged on said tank support structural floor (23).

### Claim 7 (depends on 3)

The cryogenic tank (1) of claim 3, wherein said vertical retainers (4) are further arranged for preventing rotational movement of said tank (1) about said central hub (2).

### Claim 8 (depends on 1)

The cryogenic tank (1) of claim 1, being enveloped in a tank compartment (25) having a layer of insulation material (8, 18) arranged between said planar tank bottom structure (10) and said first compartment bottom (23), and arranged between said tank wall structure (11) and said compartment wall (24).

### Claim 9 (depends on 1)

The cryogenic tank (1) of claim 1, said tank support structural floor (23) being within a tank compartment (25).

### Claim 10 (depends on 1)

The cryogenic tank (1) of claim 1, said tank support structural floor (23) being arranged in a marine vessel (30).

### Claim 11 (depends on 10)

The cryogenic tank (1) of claim 10, said tank support structural floor (23) being a deck of said marine vessel (30).

### Claim 12 (depends on 10)

The cryogenic tank (1) of claim 10, said hub retainer (20) being fixed on a horizontally oriented ship tank support structural floor (23).

### Claim 13 (depends on 11)

The cryogenic tank (1) of claim 11, said hub retainer (20) being fixed on a horizontally oriented ship tank support structural floor (23).

### Claim 14 (depends on 1)

The cryogenic tank (1) of claim 1, said tank wall structure (11) being cylindrical, said planar tank bottom structure (10) generally forming a circular plane.

### Claim 15 (depends on 1)

The cryogenic tank (1) of claim 1, said tank (1) being prismatic.

### Claim 16 (depends on 1)

The cryogenic tank (1) of claim 1 arranged for containing LNG, LPG or any fluid having a low temperature.

### Claim 17 (depends on 1)

The cryogenic tank (1) of claim 1, said planar tank bottom structure (10) being provided with a bottom liner plate (131) and said tank wall structure (11) provided with a wall liner plate (111).

### Claim 18

A marine vessel for production and storage of LNG comprising a cryogenic tank (1) for said LNG, with a planar tank bottom structure (10) supporting a tank wall structure (11), characterised in that
said planar tank bottom structure (10) has a central single point hub (2) coupled to radial structural beams (3) further arranged for supporting said tank wall structure (11), said central single point hub (2) having a substantially smaller diameter than a diameter of said tank bottom structure (10), said central single point hub (2) adapted for being held by a corresponding hub retainer (20) on a tank support structural floor (23) in said ship, said hub retainer (20) generally providing radially directed retention forces to said central single point hub (2) in the plane of said planar tank bottom structure (10) both when said cryogenic tank (1) is operating at cryogenic temperatures and when empty at ambient temperature.

### Claim 19

A marine vessel for storage and regasification of LNG comprising a cryogenic tank (1) for said LNG, with a planar tank bottom structure (10) and a tank wall structure (11) arranged on said planar tank bottom structure (10), characterised in that
said planar tank bottom structure (10) has a central single point hub (2) coupled to radial structural beams (3) further arranged for supporting said tank wall structure (11), said central single point hub (2) having a substantially smaller diameter than a diameter of said tank bottom structure (10), said central single point hub (2) adapted for being held by a corresponding hub retainer (20) on a tank support structural floor (23) in a ship, said hub retainer (20) generally providing radially directed retention forces to said central single point hub (2) in the plane of said planar tank bottom structure (10) both when said cryogenic tank (1) is operating at cryogenic temperatures and when empty at ambient temperature.

### Claim 20

A ship for transportation of LNG comprising a tank (1) for said LNG, with a generally vertical tank axis (9) and a planar tank bottom structure (10) and a tank wall structure (11) arranged on said planar tank bottom structure (10), characterised in that
said planar tank bottom structure (10) has a central single point hub (2) coupled to radial structural beams (3) further arranged for supporting said tank wall structure (11), said central single point hub (2) having a substantially smaller diameter than a diameter of said tank bottom structure (10), said central single point hub (2) adapted for being held by a corresponding hub retainer (20) on a tank support structural floor (23) in said ship, said hub retainer (20) generally providing radially directed retention forces to said central single point hub (2) in the plane of said planar tank bottom structure (10) both when said cryogenic tank (1) is operating at cryogenic temperatures and when empty at ambient temperature.

### Claim 21 (depends on 1)

The tank (1) according to claim 1, wherein said hub retainer (20) is arranged with one or more channels for filling or emptying the tank with cryogenic fluid.

### Claim 22

A method of installing a cryogenic tank (1) for liquefied gases in a vessel wherein said tank (1) comprises a planar tank bottom structure (10) and a tank wall structure (11) on a circumference of said planar tank bottom structure (10),
wherein said planar tank bottom structure (10) is provided with a generally central tank bottom hub (2) adapted for being held by a bottom hub retainer (20) on a tank support structural floor (23), said central tank bottom hub (2) having a substantially smaller diameter than a diameter of said tank bottom structure (10), wherein said method comprises hoisting the tank (1) and lowering said tank (1) directly onto said bottom hub retainer (20), with a remainder of the tank bottom structure (10) supported on insulation (8) provided between the remainder of tank bottom structure (10) and the tank support structural floor (23).