KR20070020382A - Double skin tanker - Google Patents

Abstract

The present invention relates to a double skin tanker having a steel outer skin and a steel inner skin, wherein the inner skins are spaced apart from the outer skins and enclose the cargo compartment, the outer skins and the inner skins being joined together in a rigid manner by vertical and horizontally extending elements. Connected. The connecting element is designed to have a predetermined break point or perforation, and the inner skin made of steel has a high elongation.

Description

Double shell tanker {DOUBLE SKIN TANKER}

The invention comprises an outer skin and an inner shell surrounding an individual cargo compartment and spaced apart from the outer skin, wherein the outer skin and the inner shell are rigidly connected to one another by a connecting element.

Usually, for double shell tankers, there is a risk of breaking the inner shell as well as the outer skin of the tanker. Although not common, one can expect that only the outer skin is broken and the inner shell is not broken. In the case of normal damage, the breaking force of the icebreaker, for example, the bulb of the icebreaker, damages the outer skin and deforms the inner shell via an element mounted between the outer skin and the inner cell, causing the cargo to leak. In the case of oil, this results in a well-known disaster.

The double shell tanker of the type described above is provided with a rated break point or perforation standardized on a connecting member which is at least part of the vertical inner shell member of the frame and / or at least part of the horizontal stringer according to the invention. And the inner shell is produced from high elastic steel with high breaking elongation.

The overall idea embodied by the invention is that the connecting element and / or at least some, preferably all mounting elements, between the outer skin and the inner shell comprise a standardized break point. Thus, in normal cases, forces can be exerted on the outer skin from the outside, and since the normalized breakpoints react in the direct area where the force acts, the mechanical connection to the inner shell is interrupted and the inner shell is not damaged, resulting in cargo It is not released. In the case of stronger impacts or forces acting at undesirable angles, the force also acts on the inner shell, but since the inner shell is produced from high elastic steel with high elongation, the inner shell is deformed so that cracking does not occur. Can be. Only with great force can the inner shell be broken in at most 3% of statistically known accidents.

The principle of the invention is usually realized by the deformation of the inner shell only when the outer skin of the ship according to the invention breaks in an acceptable position.

The present invention is intended to prevent leakage of cargo, in particular petroleum, in almost 100% of the accidents known or evaluated so far.

In a double shell tanker the connecting element between the outer skin and the inner shell is substantially a so-called stringer and the supporting element belongs to the vertically oriented member of the stringer and the frame. It is a honeycomb configuration formed from brace-like connections and horizontal and vertically oriented sheet metal components attached to the brace.

According to the invention, the metal sheet is provided with a standardized point of break by the perforations or is designed in the form of a line such that a plurality of rows of holes, ie circular holes with interruptions or individual long holes, are obtained in the form of perforations. do.

Preferably the perforation lines are arranged closer to the inner shell. However, it is also possible to mount these perforations or standardized break lines closer to the outer skin or to provide several such lines between the outer skin and the inner shell on the same connecting element. Also, the holes do not need to be arranged in a linear extension and the holes may be arranged at absolutely constant angles or wave-like. Substantially in the case of a force acting on the ship's hull from outside according to the present invention, the standardized breakpoints in the immediate vicinity of this force influence are excessively deformed and cut at a predetermined point so that the inner shell is not damaged and the stability of the ship is maintain.

For the shape of an elongated hole, it may be square with a substantially circular part. However, holes may also be provided which taper in the longitudinal direction towards the perforation line. In this respect the web remaining between adjacent long holes is sized to cause the web to break when a predetermined force acts on the web, and this breaking force is adjusted to the breaking force at which an expected collision with another ship is expected.

Thus, the brace member functioning as a support rest for the stringer metal sheet has formed normalized cracking points so that the normalized cracking points do not transmit force to the inner shell against fracture forces, or A significant portion of is delivered to prevent the inner shell from breaking even if it is not delivered to the inner shell or if the inner shell deforms over a relatively large area.

The core of the present invention is not only to stop the flow of force, but also to ensure that the inner shell is not destroyed except for the outer deformation of the inner shell even when the breaking force acting as the hull of the ship body from the outside is transmitted to the inner shell.

The invention is also not limited to double shell tankers but can be carried out on all double shell vessels or container ships and as a whole ensures that no cargo is released from the hull in the case of the majority of possible collisions.

FIELD OF THE INVENTION The present invention relates to a double shell tank vessel comprising an outer skin made primarily of steel and an inner shell made of steel, wherein the outer skin and the inner shell are connected to each other to form a hull. Since 2010, the EU has required such a shell for a tanker from 5000 tdw, where there is a cavity between each of the vessel's exterior float skin and the interior cargo area.

Known tank vessels (US PS 3,844,239) are provided with a metal outer skin formed of an elastic material and elastic with a liquid-tight shell therein.

Tankers are known from US 3,699,912, which are also not double shell tankers in accordance with conventional definition. In known tankers, a receptacle is located inside, and its outward wall consists of two barrier parts. These two barriers, referred to as panels, act on one another and can be deformed with respect to one another in the event of a collision so that, for example, the interior containing the crude oil remains closed against the exterior.

Double shell structures according to JP 08230775 A include conventional double shell tankers. Thus, an outer skin and an inner shell are provided, between which the Scringer deck is located as a connecting part. The objective is that the inner cell is not formed as a conventional plate in a double hull tanker but instead is formed with corrugated iron parts to achieve collision stability where the inner shell can be expanded in case of a collision and the collision energy can be absorbed by the corrugated shape. Done.

Known vehicles for the transport of chemicals (EP 0 723 908 A1) are not double hull tankers but carriers comprising an outer cell and a double wall configuration with inner and outer walls is provided. These two parts are interconnected by cross bracing elements that also function as bulkheads. Here, the external connection is fixed, the internal connection is collided so that in the event of a collision, the attachment is not broken, resulting in so-called "membrane stresses" in the external shell, and the bracing portion is provided for this purpose so that certain limited load I can only bear it.

JP 07196074 A relates to a double shell tanker, in which an elastically resilient portion or material is provided between the two walls of the outer and inner walls, respectively, but cannot withstand tensile stress. For this purpose, the outer shell is provided with longitudinal binding rivets and a number of anti-flex materials in the longitudinal direction. This element accepts the compressive forces generated by the collision to protect the inner shell in this way. A large strain force is transmitted to the inner shell at the same time via the transverse web portion during the collision, and the torsional elements mounted on both sides of each transverse web portion are subjected to tension, which are separated from the inner shell at the last corresponding deformation and only slightly It may be deformed or bent. From this idea a special longitudinal structure is arranged between the shells of tankers into which a non-tensile pressure can be loaded, and the force generated by the collision is transformed into a torsional force, which in this way causes only a slight deformation or bending of the inner shell. Provide additional torsional elements. However, this phrase provides a significant additional effect, which is not clear whether this torsional element can be designed to accommodate possible collisions and resulting deformations.

Further conventional double shell tankers can be found in Japanese Patent Publication JP 08301180 A. An outer shell made of steel and also an inner shell made of steel are provided, wherein the stringer is located between these parts. To prevent the release of oil in the event of a collision, sheet steel paneling is provided inside the inner shell. Such paneling is in this case a thin sheet comprising a thickness of 1.5 to 3 mm, ie significantly thicker than the inner shell. This steel paneling is attached by spacers. The principle of this configuration is that the inner shell remains in a liquid tight state even when several components of the outer skin and the inner cell and sufficient energy of impact have been absorbed.

Considering the prior art as a whole, which provides a possible solution to a problem similar to the one on which the present invention is based, the connection elements of the outer shell and inner shell with standardized break points or perforations in all configurations of the shell are presented. Not. In the case of a collision, it may be achieved by standardized break points or perforations that the deformation of the inevitable hull is absorbed so that the deformation takes place only where the deformation does not break the inner shell. By breaking the normalized break point, the collision energy is absorbed as strain energy. Above, the mechanical connection between the outer skin and the inner shell is interrupted so that the external force no longer acts on the inner shell at least.

The present invention includes another feature, which is the choice of the material of the inner shell, which must be a high elastic steel with high elongation. When related to a steady state without collisions, this means that the double shell structure is no longer weakened by the choice of material.

The invention is described below with reference to the drawings.

1 is a schematic view showing a portion of a hull of a double shell tank according to the present invention.

2 is a diagram showing a state in the average case.

3 is a view showing damage occurring in the hull after an impact as an embodiment.

4 is an enlarged view of the space between the outer skin and the inner shell of a double tanker according to the invention.

5 is an enlarged view of the perforation of the member of the frame or part of the stringer.

In the figure, the outer skin 10 and the inner shell 11 of a double shell tanker are shown. Between the outer skin 10 and the inner shell 11 a substantially vertically oriented member or connecting element 12 of a honeycomb or lattice configuration of the frame and a substantially horizontally formed connecting element 13, a so-called stringer ( stringer). Elements 10 to 13 are constructed of rigidity.

In FIG. 4, shown on a larger scale, a horizontal connecting element 13 and a vertical connecting element 12 are shown. The outer skin is omitted in this figure, but the inner cell 11 can be seen. 4 shows the post-collision state, with the break point normalized by a local prevailing force such that the inner shell 11 is deformed in a different manner than the outer skin (not shown) or the deformation of the connecting elements 12 and 13, respectively. 20 shows how the rated break points react.

It can also be seen that the inner shell 11 deforms smoothly without breakage. There is steel that is suitable for this deformation and especially has high breaking elongation.

5 shows three adjacently located recesses in one part of the connecting element 12 or 13. Three long holes 20 can be seen in a row, the distance between each other being chosen such that the holes are cut away and open at each deformation. The shape of the elongated hole is chosen to deviate from the circular or rectangular hole with the circular part so that the desired cut opening in the perforation line can be ensured.

1 to 3 within the scope of the present invention, in the case where the cargo compartment is not completely filled (usually 97% filling rate), the interior of the cargo compartment is reduced by deformation and the cargo is broken It is guaranteed to leak through the plate into the area of the double central longitudinal bulkhead.

Claims (4)

A double shell tanker comprising an outer skin and an inner shell surrounding an individual cargo compartment and spaced apart from the outer skin, the outer skin and the inner shell being rigidly interconnected by connecting elements extending substantially vertically and horizontally To Standardized breaking points or perforations 20 are provided on at least part of the connecting elements 12, 13 and the vertical inner wall members of the frame and / or at least part of the horizontal stringers, and the inner cell 11 has a high elongation. Characterized in that is produced in a high elastic steel, including Double shell tanker. The method of claim 1, The vertically extending connecting element 12, characterized in that the perforations 20 in the member of the frame are formed in close proximity to the inner shell, Double shell tanker. The method according to claim 1 or 2, The horizontally extending connecting element 13, characterized in that the perforations in the stringer are formed in close proximity to the inner shell, Double shell tanker. The method according to any one of claims 1 to 3, The perforated portion 20 is characterized in that formed by a row of circular holes, Double shell tanker.

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