NL1038409C2 - INFLATABLE ELEMENT FOR USE IN THE INTERNAL OF A HOLDER. - Google Patents

Abstract

The invention relates to an inflatable element for use as a damper of fluid oscillations interiorly in a holder (2) with a holder bottom wall, a holder upper wall (31) and holder sidewalls (9', 9", 10', 10"), which holder is suitable for transporting a liquefied gas with its vapour, such as liquefied natural gas or LNG; the element wall (5) comprises an element bottom wall (7), an upper wall (8) and sidewalls (13), which element in the use position floats with its bottom wall (7) on the liquid load (3) and wherein the inflatable element (4) has a thickness (d) smaller than the height between the liquid surface and the upper side wall (31) of the holder and wherein openings ( 11) are provided which extent from the element bottom wall (7) to the element upper wall (8) constituting open fluid connections.

Description

TITLE. Inflatable element for use in the interior of a container.

The invention relates to an inflatable element for use in the interior of a container with container side walls, which container is suitable for storing a liquid load; the inflatable element comprises an element wall with a bottom wall, an upper wall and side walls, which defines a closed internal space with a fixed volume for receiving the inflation gas, which element in its position of use floats with its bottom wall on the liquid load in the container of a transport - or storage device such as a tank truck, a tank container or a storage tank.

It is known that the load in transportable holders or tanks of, for example, tank lorries and road vehicles is undesirable due to various causes - for example, acceleration or acceleration or braking or deceleration due to excessive speeds in the bends or due to (almost) collisions. 15 exhibits dynamic behavior that can even lead to a vehicle tipping over. The influence is largely dependent on the type of cargo that is in the storage tank of the truck or tank truck and, for example, often consists of liquid that can move freely in the event of sudden maneuvers of the tank truck. The reciprocating or sloshing liquid can provide an extra impulse 20, thereby accelerating the tilting of a tank or truck. In order to prevent tangling or swinging in the axial longitudinal or driving direction of the liquid tank, pendulum baffles are provided in the container for the transport of dangerous liquids, but they have the disadvantage that they almost only dampen axial liquid movement and not axial movements, such as radial or tangential oscillation, do not or only slightly suppress the liquid.

Moreover, these partitions have their own mass and volume, whereby the capacity of the container is reduced. These baffles are also often fixedly mounted in a holder, making labor-intensive internal assembly, inspection, repair and cleaning necessary. Due to the fixed mounting of the partitions in the holder, a part of the impulse of the winding liquid will also be passed on to the holder and the truck and transfer forces and energy to the holder wall.

In tankers for transport by water and / or storage of liquids and gases at sea, sloshing and swinging of the liquid can also occur due to the swelling of the water and the swelling of the ship on the water. Gas tankers such as LNG tankers or carriers (LNG, Liquefied Natural Gas) generally contain two or more containers in which gas cooled to liquid is supplied at a temperature of approximately minus 162 ° C at atmospheric pressure stored and / or transported. The holders can be of the 'self-supporting' type, often in the form of a sphere or of the 'membrane' type, which are directly supported by the hull of the ship. The self-supporting containers form much empty, unusable, space between the spheres, as a result of which the capacity of the ship is lower than for ships of the 'membrane' type which make better use of the available space in the hold. Self-supporting containers do have a greater resistance to the forces exerted by splashing liquid and are therefore preferred for use as storage tanks on the high seas. With the 'bulb' type, the gas is stored under pressure, so that the wall thickness of the 'bulbs' is considerable, which entails high costs and also a high weight.

With 'membrane' type containers, the gas to be transported is present in both liquid and vapor form at atmospheric pressure. The liquid 'boils' through supplied energy as a result of heat conduction and also through energy absorbed in the liquid as a result of the sloshing or swelling of the liquid charge. The swinging or rocking of the liquid in the containers of the gas tanker depends on the swell of the water but also on the degree of loading of the gas tanker. When the degree of loading increases, the ship will lie deeper in the water, as a result of which the natural frequencies and swinging and rocking frequencies of the ship and of the cargo in the holders will change. In gas tankers, moreover, the effect occurs that the sloshing and rocking of the liquid leads to energy absorption and thus to evaporation of liquid, as a result of which additional cooling is required or the excess energy must be removed in another way. In the following, the term (Liquified Natural Gas) LNG tanker means a gas tanker 25 suitable for storage and / or transport of liquid gas.

These effects make it impossible to fully utilize the capacity of the container and generally limit the degree of filling to values between 10% and 75%. This results in operational limitations, especially with LNG shuttle tankers operating in the spot market, who cannot discharge or load the commercially required or operationally necessary amount of gas, for example because the prevailing sea conditions make it impossible for a buoy mooring, causing trade to be lost. Also for LNG tankers, for the exploitation of oil and natural gas fields, which are used as floating storage with, for example, a borehole, the greatest possible capacity is desired with the greatest possible stability in the event of wave impact or swell of the water. LNG tankers are also used for so-called 'regasification', whereby the liquid (natural) gas is evaporated and supplied to customers using ambient heat.

3

The liquid gas forms a liquid-vapor equilibrium in the container depending on the temperature and pressure. The pressure and temperature are selected such that the gaseous product under atmospheric conditions is present in the container mainly as a boiling liquid. The free space above the liquid is therefore completely filled with vapor or gas of the product in the liquid state.

It is known to place an inflatable bag, airbag, cushion or balloon in the interior of a container of a transport or storage device and to pressurize it with an inflation gas, such as for example nitrogen or air, with the aid of, for example, a compressor or with inflation gas from a high-pressure reservoir or storage such that the balloon fills most of the free space of the container and thus limits the splashing of the liquid and the formation of vapor. This inflatable element preferably forms a form and / or force-tight connection with the inner container wall, whereby a good damping effect is obtained on movement or swinging of the liquid. A suitable embodiment is an inflatable element which is provided with a harmonica wall or otherwise stretchable or foldable wall or walls, which fold out and fold in or stretch and contract, respectively, when supplying or discharging inflatable gas into the inflatable element. This type of inflatable element is not suitable for placement in containers of gas tankers since the liquid and the vapor must remain in contact with each other to allow cooling and vapor removal.

The invention therefore has for its object to provide an inflatable element which dampens and strongly restricts the flow of liquid into the container without necessarily filling the entire free space with the inflatable element.

To this end, the invention provides the inflatable element which is provided with a thickness that is smaller than the height between the free liquid surface and the upper side of the container and furthermore is provided with openings which extend from the bottom wall to the top wall. With the above measures, evaporating liquid can flow through the inflatable element to the vapor space 30, while still winding of the liquid is damped by the presence of an inflatable element on the surface of the liquid.

In a preferred embodiment, the inflatable element is provided on a container side wall with a friction valve or stabilizing body. As a result of this provision, the inflatable element will find stability on its edges, without creating any resistance when moving the element due to a change in the liquid level.

4

The inflatable element is preferably provided on four opposite container side walls with a friction valve or stabilizing body. In particular, the stabilizing body extends all around the entire peripheral edge of the inflatable element and forms a one-piece peripheral body. By arranging a friction valve on four opposite side walls and designing it as a one-piece body, the inflatable element will not be able to move easily up or down along the container side walls so that the inflatable element has a stabilizing and damping effect on fluid swings.

In the position of use, the bottom wall is preferably substantially flat and the top wall is curved, curved or multi-curved or curved. This makes it more difficult for the inflatable element to be deformed by fluid movements in the container, so that fluid swings are properly damped.

Preferred is the embodiment in which the friction valve is an inflatable body or element comprising a closed internal space for receiving inflation gas. With these measures, the amount of friction or resistance between the friction valve and the inner wall can be adjusted by making the friction valve thicker or wider in the horizontal direction and / or by lengthening the friction valve in the vertical direction thereby creating a larger friction area between 20 friction valve and the inner wall of the container.

In particular, a connecting channel is provided between the interior space of the friction valve and the interior space of the inflatable element. Through this connecting channel, the friction valve will become longer and thicker as the pressure in the interior of the inflatable element is increased.

An advantage is the embodiment in which the connecting channel is an elongated gap, which forms an open fluid connection between the inflatable element and the friction valve. A good fluid connection is hereby formed between the inflatable element and the friction valve, whereby the clamping force between the upright walls of the container can be maintained and the stabilizing frictional force between the friction valve and the walls is maintained.

In an alternative embodiment, support elements are provided which extend from the top wall of the inflatable element to the top wall of the container.

In particular, the support elements are inflatable elements which can be adjusted in height by means of supplying or removing inflatable air. These support elements hold the inflatable element in place on the surface of the liquid so that damping of liquid swings will also occur. Because the support elements are retractable and extendable, the vertical position of the inflatable element can be adjusted to the degree of filling of the container.

5

A first alternative embodiment of the friction valve is characterized by a substantially horizontal flexible valve which is connected to a side of the inflatable element by means of a turning or bending point.

In particular, the flexible valve is made of a sturdy, elastic material 10 such as a rubber or a plastic material. With this embodiment it is possible to provide a closure which can easily move along projecting parts of the wall such as wall kinks or tongues of a gas tanker of the 'membrane' type.

A second alternative embodiment of the friction valve is characterized in that the friction valve is a flexible roller that is rotatably attached to a side wall of the inflatable element.

In particular, the flexible roll is made of a flexible and compressible material such as a spongy material and / or fiber material such as hair. The roller rotates about its axis and protruding parts of the wall such as wall kinks or tongues compress the material so that moving the inflatable element up and down is easy, without causing damage to the wall and / or the inflatable element.

The invention also relates to a transport or storage device 25 comprising a holder with inflatable element.

The invention will be explained in more detail below with the aid of the drawing with some exemplary embodiments of the inflatable element, wherein features and other advantages will emerge.

30

FIG. 1 is a perspective view of an LNG tanker provided with a few containers for liquid gas;

FIG. 2 shows in more detail a holder of Fig. 1 provided with an inflatable element; 3 shows in plan view the holder provided with inflatable elements with openings,

Fig. 4 shows in more detail a friction valve near a container side wall, 6

Fig. 5A shows in side view an alternative embodiment of the inflatable element provided with support elements,

Fig. 5B shows a perspective view of the support elements of Fig. 5A,

Fig. 5C shows a top view of the embodiment of Fig. 5A, Fig. 6A, 6B, 6C show the flexible valve, an alternative embodiment of the friction valve,

Fig. 7 shows the roller valve, a second alternative embodiment of the friction valve.

Fig. 1 shows a transport or storage device 1 provided with a few containers 2. In this example, the transport device is a gas tanker 1, which is provided with eight containers 2 or tanks which are adapted to transport a liquid load 3; in this example in particular for a liquid gas such as LNG (Liquid Natural Gas). A gas tanker suitable for transporting liquid gas is hereinafter referred to as an LNG tanker. The LNG tanker is provided with means and devices for keeping the gas liquid by maintaining the correct temperature and pressure.

In Fig. 2 the holder 2 is further shown with holder side walls 9 ', 9 ", 10', 10", which holder 2 is approximately three-quarters filled with liquid gas 3, so that the liquid upper surface is approximately three-quarters high in the holder 2 lies. On top of the liquid 3, the inflatable element or airbag 4 floats, which element wall 5 defines a closed interior space 6, the element wall 5 being formed by a flat bottom wall 7, a multi-curved top wall 8 and side walls 13; to which friction valves 20 ', 20 "are connected, which closely connect to the holder side walls 9', 9", 10 ', 10 "of the holder 2. The inflatable element 4 is provided with a thickness d that is smaller than the height between the free liquid surface and the top 31 of the container 2, so that the inflatable element 4 fills only a small part of the vapor space of the container The inflatable element 4 is connected to inflation tools (not shown) such as, for example, an air compressor and a control unit with which inflation gas Such as, for example, air or another gaseous product can be introduced into and out of the inflatable element 4. Control means, such as, for example, control lights, can also be provided in a control chamber or space of the gas tanker.

The inflatable element 4 of Fig. 2 is provided with openings 11 which extend from the bottom wall 7 to the top wall 8. Through these openings 11 the vapor phase is in open contact with the liquid phase so that the evaporated liquid can escape through the inflatable element 4 or condensing vapor can flow back to the liquid. In such liquefied gas containers 2, at a temperature 7 which is much lower than the ambient temperature, energy loss occurs due to heat conduction in the container 2 and also due to absorption of energy in the form of heat as a result of the liquid swinging and tangling in the holder. The stabilization of the liquid and the damping of the liquid oscillations limits the energy flow to the holder 2 and ensures an energy saving.

In Fig. 3 the inflatable element 4 is shown in top view in the holder 2 with openings 11 provided. The number of openings 11 can vary, in general it can be said that a regular distribution of these openings 11 over the top wall 8 is advantageous .

In Fig. 4 section IV-IV of Fig. 3 is shown in detail of the inflatable element 4 and the element wall 5, in this exemplary embodiment formed by upper wall 8 and lower wall 7. Some parts of the element wall can be provided with a reinforcing element such as a textile carrier or fiber network. The bottom wall 7 is preferably provided with a reinforcement to prevent distortion and to maintain a flat surface, which is advantageous for damping the oscillations of the liquid 3. Around the top wall 8 of the inflatable element 4 of a regular to provide curved surfaces extending in the longitudinal direction, the inflatable element is provided with connecting parts 12 between the top wall 8 and the bottom wall 7. The inflatable element 4 is provided with a thickness d which is smaller than the distance between the liquid surface and the top 31 of the holder 2.

Furthermore, in Fig. 4 the friction valve 20 "is shown, designed as an inflatable body provided with an inner space 21. The friction valve 20" extends parallel to the container side wall 10 "with the friction wall 23. The friction wall 23 is in contact with the inside 19 of the container side wall 10 "and is preferably clamped against it. As a result, frictional force is created between the wall and the friction valve 20 "and the inflatable element 4 connected to the friction valve 20", whereby the inflatable element 4 is stabilized on the liquid surface and the formation of swinging of the liquid is made difficult and swinging of liquid is made more difficult. muted. Friction valves can be arranged on one, two or all four side walls of the inflatable element 4 or can be designed as a body extending around the entire peripheral edge. The amount of resistance between the container side wall and the friction valve can be adjusted by adjusting the amount of air in the interior space 21 of the friction valve.

8

The friction valve 20 ', 20 "can be provided with a separate inflation means or control system, but the internal space 21 of the friction valve can also be in open communication with the internal space 6 of the inflatable element 4 so that, by inflating or deflating, the inflatable element can at the same time also vary the friction on the walls of the holder 2. To that end, connecting channels 22 can be provided between the inner space 6 of the inflatable element 4 and the inner space 21 of the friction valve 20 ', 20 ". In a special embodiment, the connecting channels 22 can be an elongated slit which for the most part extends horizontally between the inflatable element 4 and the friction valve 20 ', 20 ". The friction valve 20', 20" is also referred to as flap or wing .

Because the inflatable element 4 floats on the liquid surface of the liquid load 3 - but does not fill the entire vapor space - the inflatable element 4 will have an inhibitory or delaying effect on the formation of liquid swings and also have a damping effect on swinging or sloshing movements of the liquid 3 in the container 2. This damping effect can be further increased by further inflating the inflatable element 4 so that the friction valve 20 'will be unfolded to the extent that it will make contact with the inside 19 of the container side wall 10 "of the container 2. In this inflated position, the inner space 21 of the friction valve 20 'will also be completely filled with inflation air, so that friction will occur between the container side wall 10 "and the friction valve 20', whereby the inflatable element will have a strong damping effect. on fluid sways in the container 2.

25

In the alternative embodiment of FIG. 5A, 5B, 5C of the inflatable element 4 ', with a thickness d and through openings 11, the friction valves 20', 20 "have been replaced by a support elements 30 which extend from the top wall 8 of the inflatable element 4 to the top wall 31 of the holder 2. These support elements 30 also hold the inflatable element 4 'in place on the surface of the liquid 3 so that there will also be damping of liquid swings. The support elements 30 are preferably retractable and extendable so that the vertical position of the inflatable element 4 can be adapted to the degree of filling of the holder 2. The support elements 30 are therefore preferably provided with a separate system for the control and supply and discharge of inflatable air.The support elements can be provided with a harmonica wall for the easy retraction and retraction of the supports 30.

9

Figs. 6A, 6B, 6C show a first alternative embodiment of the friction valve, suitable for use in containers 2 of the 'membrane' type. This holder 2 has a thin membrane wall 45. These walls 45 are provided with bends 46 or harmonica structure or also protruding tongues from overlapping membranes, as a result of which the expansion and shrinking of the wall material can be absorbed as a result of large differences in temperature. These protruding kinks or tongues 46 are disadvantageous for operating the inflatable element according to the invention. Therefore, in this embodiment the inflatable element 4 "is provided with a flexible valve 40, which is arranged on a side wall 13 of the inflatable element 4 by means of a pivot point 41.

In Fig. 6A, the inflatable element 4 "and the flexible valve 40 moves downwardly on the liquid surface in the container 2. In Fig. 6B it is shown that flexible valve 40 rests against the top of the wall bend 46 and is tilted slightly around the pivot point 41 relative to the inflatable element 4 ".

In Fig. 6C, the flexible valve 40 of the upwardly moving inflatable element 4 "is tilted down so far about the pivot point 41 relative to the side wall 13 of the inflatable element 4 that the flexible valve 40 passes the wall bend 46 The flexible valve 40 ensures a good seal with the membrane wall 45 of the container during the up and down movement of the inflatable element and also ensures a clamping position of inflatable element 4, whereby sloshing liquid can be prevented or damped.

In a second alternative embodiment of the friction valve in FIG. 7, a flexible roller 50 is applied, which is rotatably mounted about a rotation axis 51 on side wall 13 of inflatable element 4 "'. The rotation axis is connected to inflatable element 4" "in a known manner, such as with brackets or the like. The flexible roller or roller valve 50 is made of a flexible, compressible material such as spongy material or of loose fibers such as hair. As a result, the roller valve 50 can easily pass obstacles protruding from the wall, because the rolling material is pressed in at the location of the obstacle, such as a wall buckle 46 or tongue. The flexibility of the material of the flexible roll 50 can be easily adapted to the mechanical strength of the wall 45 or the membrane mounted thereon and to the necessity of exerting a clamping force on the inflatable element to prevent fluid splashing or dampen the swinging of the fluid.

10

The inflatable element 4, 4 ', 4 ", 4"' can be provided with a single large internal space with thickness d or can be divided into compartments such as sub-elements placed in the longitudinal direction of the holder.

The inflatable element can be fitted loosely in the holder or be fixedly connected to the holder, but the element is preferably connected to the holder in such a way that a slight force is exerted on the holder side wall of the holder.

The inflatable element or can be manufactured from any suitable material such as plastic or textile.

1 038 4 09

Claims (15)

An inflatable element for use in the interior of a container (2) with 5 container side walls (9 ', 9 ", 10', 10"), which container is suitable for storing a liquid load (3); the inflatable element (4) comprises an element wall (5) with a bottom wall (7), an upper wall (8) and side walls (13), which defines a closed internal space (6) with a fixed volume for receiving the inflation gas, element in the position of use with its lower wall (7) floats on the liquid load (3), characterized in that the inflatable element (4) is provided with a thickness (d) that is smaller than the height between the free liquid surface and the top side (31) of the holder and furthermore provided with openings (11) which extend from the bottom wall (7) to the top wall (8). 15 Inflatable element according to claim 1, characterized in that the inflatable element (4) is provided on a container side wall (9 ', 10') with a friction valve or stabilizing body (20 ', 20 "). Inflatable element according to claim 2, characterized in that the inflatable element (4) is provided with a friction valve on four opposite holder side walls (9 ', 9 ", 10', 10") of the holder (2). stabilizing body (20 ', 20 "). Inflatable element according to 3, characterized in that the stabilizing bodies 25 (20 ', 20 ") extend around the entire peripheral edge of the inflatable element (4) and form a one-piece peripheral body. 5. Inflatable element as claimed in any of the foregoing claims 1-4, characterized in that in the position of use the bottom wall (7) is substantially flat and the top wall (8) is curved, curved or multi-curved or curved. An inflatable element according to any one of the preceding claims 2-4, characterized in that the friction valve (20 ', 20 ") is an inflatable body or element comprising a closed internal space (21) for receiving inflation gas. 4 09; 35 Inflatable element according to claim 5, characterized in that there is a connecting channel (22) between the interior space (21) of the friction valve (20 ', 20 ") and the interior space (6) of the inflatable element (4) to provide. The inflatable element according to claim 6, characterized in that the connecting channel (22) is an elongated gap that forms an open fluid connection between the inflatable element (4) and the friction valve (20 ', 20 "). 9. Inflatable element as claimed in claim 1, characterized in that support elements 10 are provided, which extend from the upper wall 8 of the inflatable element 4 'to the upper wall 31 of the holder 2. 10. Inflatable element according to claim 8, characterized in that the support elements (30) are inflatable elements which can be adjusted in height by means of supplying or removing inflatable air. Inflatable element according to one of the preceding claims 1-6, characterized in that the friction valve is a substantially horizontal flexible valve (40) which is connected to a side wall (13) by means of a turning or bending point (41) ) Of the inflatable element (4 "). An inflatable element according to claim 11, characterized in that the flexible valve (40) is made of a sturdy, elastic material such as a rubber or a plastic material. 25 An inflatable element according to any of the preceding claims 1-6, characterized in that the friction valve is a flexible roller (50) which is rotatably attached to a side wall (13) of the inflatable element (4) ""). An inflatable element according to claim 13, characterized in that the flexible roller (50) is made of a flexible and compressible material such as a spongy material and / or fiber material such as hairs. 15. Transport or storage device (1) comprising a holder (2) with inflatable element (4, 4 ', 4 ", 4'") according to one of claims 1-9. 1 0 3 8 4 09