WO2008110246A1 - Flexible inner tank for the tank of a tanker - Google Patents

Abstract

The invention relates to a flexible inner tank for the tank of a tanker, particularly a product tanker having an inserted foldable film structured as an inner tank, wherein the inner tank may be caused to fold into a predetermined shape by a pulse of force.

Description

"Flexible inner tank for the tanks of a tanker"

Tankers are often loaded only on one way and can thus take advantage of only half of their possible payload. In order to be able to use their capacities on both routes, they have to undergo expensive cleaning. This is changed by constructing a flexible tank inside each tank for two or more different liquids. Flexible tanks are already being used to transport fluids in containers, as motor sport tanks and in other extreme applications. Tankers could be equipped with flexible tanks so as to be e.g. To transport oil and fresh water at the same time or on return journey in a steel tank construction. It would also be possible to retrofit existing tankers.

Fluids can be stored in this way either in a rigid or flexible tank. When constructing the installed flexible tank, make sure that it leans close to the structure of the rigid tank at maximum filling level in order to make maximum use of the available storage space. On the other hand, the flexible tank should be empty when not in use Minimum, so a very small storage space, fold.

In the prior art flexible tanks with floats are known.

When folding, by floating the float 1 through the medium in the rigid tank (Figure 2 and 3) of a previously outwardly curved body (foil tank), it may happen that the flexible body rather outward (away from the body interior) than inward (for Body interior) coincides. As a result, the outer skin of the body can be damaged by grinding / friction on the steel tank wall. In addition, a loss of volume in the second tank would be expected in this case, since this is not folded to a minimum storage volume. In addition, there are more technical problems. These are as follows:

The outer skin is relatively thin (about 5 mm) and therefore can not be exposed to high compressive forces. In the filled state, the outer skin therefore describes the contour of the rigid tank, but does not itself have a shaping structure.

When floating, the outer skin grinds / rubs against the steel tank wall and wears off.

When folding, the process is the random principle. Kinks do not occur at previously defined points on the surface of the flexible tank, but depend on the random starting position of the flexible tank

Tank surface and so a favorable folding to a minimum storage volume impossible do. (See picture 2 and 3)

The purpose and the object of the invention is now to make the folding process of a nearly structureless body from the outset the best possible, so as to be able to cause the desired effect as often as desired.

For example, in the case of a "multi-purpose tanker", this would be the "inward folding" of the flexible tank. Friction damage would be ruled out as opposed to "outward wrinkles" as the steel tank wall is not touched, as well as allowing the flexible tank to fold more compactly when not in use.

Also known in the art are constrictions at predefined distances that allow folding in the desired manner. (Accordion principle) Disadvantages are the extensive production of the flexible body (the vulcanization between the individual sections), the susceptibility of the constrictions to cracking and no adaptation of the flexible body to a rigid shell. This of course means loss of transport volume, especially in our case. For large flexible tanks, strength issues may also play a role.

The invention has the object to avoid the disadvantages of the prior art. This is achieved according to the invention by a pulse which acts on the surface of the flexible tank. This is a short-term, possibly perpendicular force directed to the surface, which predetermines such a direction of buckling from the outset. This force can be both a pressure, as well as a tensile force. The power sources can be ropes, pistons, vacuum and liquid or gas jets.

Brief description of a preferred embodiment: Impulse by means of rope (mechanical):

Train from inside to predefined draw points (attachment points mostly in the center of gravity of the flat) on the flexible inner wall. For corner bodies (eg prism), they must also be in the corner edges.

A rope around the body shortens and thus reduces the cross section at a previously defined point.

Further explanation:

Impulse by means of plunger (mechanical):

Pressure from outside to inside of the flexible body wall usually in the center of gravity of the flexible tank wall outer surface.

Pulse by means of a liquid or a gas (such as air):

Ejection of liquid jets directed towards the body wall or gas ejection at predefined positions, which are selected as the starting point of the "fold" for folding, thus functioning like a pressure stamp.

Impulse by negative pressure: Within the flexible body, a negative pressure is generated, which lets the body walls come inward. The negative pressure is generated by using a fast Pump is deprived of air inside the hermetically sealed tank.

The tank 2, 7 to be folded is prepared so that points are attached to its area centers and the vertical edges of the areas to be folded. At these points ropes 8 are fixed, which converge in the middle of the tank to a node. Perpendicular to this, another rope is attached to the junction. If you pull now during the floating (by the medium 3 in the rigid tank 4 and the

Float 1) on the vertical rope (eg: with winch and engine), this affects the position of the node 9. All connected to the tank ropes tension and shorten their horizontal distance. The surfaces of the tank thus arch jerkily inward. If this relative movement is so strong that the entire shell of the tank is within an imaginary volume 11 between the outermost breakpoints of the flexible tank after the momentum, then let the tank fold up without the risk of it folding outwards. It should be noted that the train on the vertical rope does not have to be maintained throughout the folding process. It is sufficient to pull the outer skin over the previously indicated limit 11.

With the help of flexible ropes (eg bungee cord), a flexible body, such as the foil tank, is brought in to collapse. The ropes, which are stretched around the flexible tank, are incorporated into tubes of the same material as the foil tank.

Due to its restoring force, the prestressed rubber rope generates an impulse inwards as soon as the film is pumped out of the fluid inside the tank. This will allow the film to fall inwards in a controlled manner.

Once the foil tank is reused and filled, the hydrostatic pressure of the fluid re-expands the tank and rope. The rope serves as an energy storage of the restoring force, which later achieved the already mentioned effect.

There are the special advantages:

Free adaptation of the flexible body to exne rigid shell, without having to describe the shape of the body beforehand, as in the Zieharmonikaprinzip.

Space-saving folding against uncontrolled folding. No wear and damage to the flexible structure of the inner tank.

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List of reference numbers:

In the figures, from which further inventive details are removable, are designated with:

1 floating body

2 bagged foil tank after pumping a fluid from its interior

3 Tank contents 4 Ship hull with conventional rigid tank wall

5 rope loop - by reducing its radius, it impulses the tank -

6 pump takes air from the tank - it creates a vacuum, which causes the tank to collapse - 7 film tank

8 rope

9 Junction where the individual wires come together

10 attachment point of the wire rope on the tank wall 11 volume thought

Claims

- 7 -PATENT TESTS

1. Flexible inner tank for the tanks of a tanker, in particular a product tanker with an inserted, designed as an inner tank foldable film, wherein the film attack points for force pulses and wherein the inner tank by at least one force acting on the points of attack force pulse for folding in predetermined shape can be initiated.

Flexible inner tank according to claim 1, characterized in that the force pulse is a mechanical impulse, e.g. an impulse exerted by ropes.

A flexible inner tank according to claim 1, characterized in that the force pulse is an external hydraulic or pneumatic impulse generated by gases or liquids, e.g. in beam form, is exercised.

4. Flexible inner tank according to one or more of the preceding claims, characterized in that the film designed as an inner tank has points of application for force pulses which are distributed over the tank in such a way that a single-fold force network is created when the pulse is released.