SYVERTSEN KAARE (NO)
| GB892044A | 1962-03-21 | |||
| US3457622A | 1969-07-29 | |||
| US3261586A | 1966-07-19 | |||
| US6082676A | 2000-07-04 |
| C l a i m s 1. Cryogenic tank for use in vessels where the tank is assembled between two horizontal foundations (8, 9) or deck, characterized in that the tank rests on the lower foundation (9), that the top of the tank is connected to the upper foundation (8) with an upper cylindrical skirt (7), that the upper cylindrical skirt (7) has a diameter which is smaller than a diameter of the cylindrical part of the tank (1) and that the upper cylindrical skirt (7) rests on an inner area of an horizontal outer part (4) of the top of the tank, wherein the outer part (4) with its flexibility is arranged to receive changes of the upper and lower foundations' (8, 9) positions with respect to each other as well as to receive changes of the dimension of the tank due to temperature changes. 2. Tank according to claim 1, characterized in that the upper cylindrical skirt (7) is arranged to transmit lateral forces from the tank to the upper foundation (8). 3. Tank according to claim 1-2, characterized in that the tank is connected to the lower foundation (9) with a lower cylindrical skirt (3) which is arranged to receive forces both in the axial direction of the tank and the lateral forces. |
Background of the invention
The present invention regards a cryogenic tank for use in vessels according to the preamble.
Particularly for tanks for cryogenic gas or liquid where the tanks are in motion such as production units or transport units in vessels there are strict requirements with regards to leakages. Such leakages will arise if the tank is subjected to dynamic loads giving rise to tensions which again can lead to formation of cracks in the material of the tank. Dynamic loads can arise due to direct loads on the tank or due to dynamic deflections of supporting structures.
Cryogenic tanks are also subjected to significant deflections based on large temperature variations. This must be possible to handle without introducing too high tensions in the tank. It is also important to exploit available volume on board a vessel in the best possible way and to have an appropriate tank partitioning with regards to redundancy and maintenance and therefore the tank must be designed with this in mind. In some cases it is also important that the area above the tank can be exploited, that is, the tank should be possible to build in under for instance a deck with equipment.
Background
There are several types of cryogenic tanks with different design and support including some that satisfy some of the conditions as described above. From the existing art we will mention the patent texts of US 347 622, for a somewhat different area, and US 6 082 676 for a launch or space vehicle, where a skirt is used as foundation for the tank.
Summary of the invention
The tank support according to the present invention however complies with all the conditions described above. This is achieved according to the definition of the tank as described in the features of the claims.
With the tank according to the invention the support is achieved giving rise to small dynamic loads in the tank. Thus an efficient way of receiving deflections in the foundation and deflections from temperature variations are achieved. Furthermore, an excellent exploitation of available volume with appropriate tank partitioning is achieved. The embodiment also gives the opportunity for placing equipment on a deck above the tank. Brief description of the drawings
On the drawing the only figure shows a vertical section through a cryogenic tank according to the invention.
Detailed description of an illustrative embodiment
The tank according to the invention comprises a vertically positioned tank with a middle cylindrical part 1. The tank has a top plate of which the outer part 4 is horizontal, while the middle part 5 is preferably of a conical shape. The radial inner part of the top plate's horizontal outer part 4 receives a vertically positioned upper cylindrical skirt 7, said second end of the skirt is attached to an upper foundation 8 or deck. The upper cylindrical skirt 7 has a smaller diameter than the diameter of the cylindrical part 1.
The tank further comprises a spherical bottom 2 which is connected with the cylindrical part 1 and which is connected to a cylindrical skirt 3 in the transition 6 between the cylindrical part 1 of the tank and the spherical bottom 2. The cylindrical skirt 3 supports the tank against a bottom foundation 9 or deck.
Since the outer part 4 of the top plate of the tank is horizontal said part will constitute a flexible mechanism in the vertical direction of the tank since the horizontal outer part 4 of the top plate will be flexible for vertical movements. This will efficiently receive vertical deflections from temperature changes. At the same time this mechanism will efficiently transmit lateral forces between upper foundation 8 and the tank and between lower foundation 9 and the tank. Furthermore this enables the encapsulation of the tank under an upper foundation 8. The cryogenic tank according to the invention combines efficient loading reception from the content of the tank with efficient exploitation of available volume in places where the volume is to comprise a plurality of tanks.
The skirt 3 can suitably be embodied in stainless material for reducing the heat conduction between the tank and the foundation 9 that the skirt 3 rests upon.