US 4,207,827 AGranted

System, tooling and method of construction of cryogenic tanks for LNG tankers and for LNG storage

OwnerMichel Gondouininventor

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Abstract

Prefabricated rigid insulating panels of great length, made of a fiberglass reinforced prestressed foam enclosed in a gas tight envelope and covered on their inner face by a folded metal membrane are glued directly to the cavity walls of the load bearing structure of a cryogenic tank by means of variable thickness adhesive mastic strips, which also separate channels for a gas circulation against the panels' back face. The beveled edge surfaces of adjacent panels are rigidly bonded under pressure. Panel handling, gluing operations, and membrane welding inside the closed space of a tank are done using telescopic towers fitted with four mobile arms, one of them supporting a worker-carrying bucket. Complete self standing inner tanks may also be assembled outside and inserted into the cavity of a vessel before it is covered over. Inflated air hoses attached to the outer faces of the inner tank center it inside the cavity during the injection and curing of a liquid thermosetting bonding agent between the cavity walls and the inner tank. The hoses subsequently provide channels for a gas circulation against the back face of each panel for monitoring its integrity.

Claims11

Dependent claims

A system of membrane-type cryogenic tanks for bulk storage and for marine transportation of liquid cryogens, comprising rigid insulating walls, a bottom and a roof covered on an inner face and edges of said tank by a flexible membrane and supported on an outside face of said tank by an inner surface of a load-bearing tank structure, such as the hull of a tanker, presenting limited roof hatch openings when completed, and more specifically a system in which

(a) said insulating walls, bottom or roof of said cryogenic tank are made exclusively of prefabricated impervious rigid insulation panels bonded to each other in a rigid surface contact along their entire edge surfaces, by means of fast curing thermosetting adhesives to form a rigid structure;
said prefabricated panels presenting a face in close proximity to said liquid, which is individually covered by a weldable cryogenic metal membrane fastened by deformable means to longtudinal edges of said panels during their prefabrication to provide a thermal-shock resistant barrier and said panels also presenting a back face which is partly covered by discontinuous fast curing thermosetting adhesive means of variable thickness to provide a surface to surface contact bond between said back face of said rigid panel and an irregular inner surface of said load-bearing tank structure over a fraction of said panel back face area, said fast curing thermosetting adhesive means being disposed in parallel bands so as to provide means for a gas circulation between said load-bearing tank inner surface and said panel back face,
(b) said composite panels, being structurally equivalent to slender beams of length nearly equal to the height of a tank and which, exhibit sufficient rigidity to permit their handling, positioning and assembling to the performed in a single operation, by means of tooling designed so that the assembly line method of construction should be applicable to such a system.

A system according to claim 16 comprising:

(a) trihedral panels located at the corners of a prismatic tank,
(b) edge panels extending between said trihedral panels, along the full length of the edges of said tank,
(c) flat panels extending along said tank's wall, bottom or roof over the full distance separating such opposite edge panels, all said panels being made of rigid insulating foam prestressed in compression in the course of panel fabrication, such compressive prestressing being applied transversely to each panel by means of taut glass fibers stretched obliquely within an impervious glass-fabric-reinforced envelope totally surrounding each panel, and said applied prestressing compression effectively compensating the tensions developed in the foam of each panel by thermal stresses and by localized anchoring forces applied while the tank is in service,
(d) thermosetting adhesive means providing a rigid bond between adjacent panels over the entire area of their edge surfaces, and
(e) thermosetting adhesive means providing a resilient bond between the back face of each said panel and the load bearing tank inner wall over a fraction of their respective areas.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/853,866Filed 22 Nov 1977 · continuation in part
Priority: 20 Aug 1976
Granted: 17 Jun 1980
Term ends: Not estimatedThe source records don’t support an estimate.

Classification27 codes

B63B 25/12
Fluid: closed
B63B 73/20
Building or assembling vessels or marine structures, e.g. hulls or offshore platforms: building or assembling prefabricated vessel modules or…
B63B 73/60
Building or assembling vessels or marine structures, e.g. hulls or offshore platforms: characterised by the use of specific tools or equipment;…
F17C 3/025
With provision for thermal insulation: bulk storage in barges or on ships