JP5863820B2 - Expansion material used inside the holder - Google Patents

Description

The present invention relates to an expansion material for use as a shock absorber for fluid vibration inside a holder.
The holder is a closed space and is suitable for storing liquid cargo. The holder is specifically suitable for transporting liquefied natural gas, ie liquefied gas such as LNG, along with its vapor. The closed holder includes a holder bottom wall, a holder top wall, and a holder side wall. The inflatable material includes a material wall that defines a closed interior space having a fixed volume for containing an inflating gas. The material wall includes a material bottom wall, a material top wall, and a material side wall. In the use position, the material bottom wall touches the free liquid surface of the liquid cargo and the expanded material floats on the free liquid surface.

Loads in transport tanks (tank cars) and road trucks can be caused by various reasons, for example by acceleration or speeding up, by braking or deceleration, by high speed driving on a curve, or by a collision (on the verge). It is known that a change in direction can cause undesirable dynamic behavior and can even cause the vehicle to roll over.
This effect depends mainly on the type of cargo contained in the storage tank, truck or tanker. For example, a freely movable (low-viscosity) liquid is easily moved by a sudden handle operation of a tanker. Further back-and-forth movement or sloshing of the liquid can create additional impact forces that can accelerate the rollover of the tanker or truck.
The baffle plate is attached to an internal holder with a volume exceeding a certain limit by legal regulations to prevent liquid sloshing or vibration in the longitudinal direction of the shaft or in the direction of operation of the tank. These baffle plates have the disadvantage that they only reduce axial liquid movement, and non-axial liquid movement, for example radial or tangential movement, is not reduced or only slightly reduced. . Furthermore, these plates have their own mass and volume, thereby reducing the capacity of the holder. In addition, these plates are usually fixedly mounted inside the holder, so that considerable labor is required for internal mounting, inspection, repair and cleaning. Furthermore, the plate fixedly attached inside the holder transmits a part of the impact force and energy of the vibrating liquid to the holder and the holder wall.

Even in tanker ships for water transport and / or for storing liquids and gases at sea, liquid swaying and sloshing may occur due to wave swells and vertical movements of the ship over the water.
Gas tankers such as LNG tankers or carriers (LNG, liquefied natural gas) typically contain two or more holders. Within the holder, the gas is cooled to a liquid at atmospheric pressure and a temperature of about minus 162 ° C. and stored and / or transported. The holder may be a “self-supporting” type, usually a sphere, or a “membrane” type supported directly by the hull. In the self-supporting holder, a lot of empty space is generated between the spheres. Therefore, the capacity of a ship having a self-supporting holder is smaller than that of a “membrane” type ship. “Membrane” type ships make more efficient use of the available space in the hold. The self-supporting holder is preferably used as a storage tank at sea because it has a great resistance to the force generated by the sloshing liquid. In the “sphere” type, the gas is stored under pressure, so the wall thickness of the “sphere” is quite thick, which increases cost and weight.

In “membrane” type holders, the transported gas exists in the form of liquids and vapors at atmospheric pressure. The liquid "boils" as a result of the energy supplied by heat conduction and the energy absorbed by the liquid due to the sloshing or undulation of the liquid cargo. The rocking of the liquid in the gas tanker holder is affected by the wave swell, but is also affected by the load of the gas tanker. When the load increases, the ship sinks deeper into the water, and the natural frequency, vibration frequency, and rocking frequency of the load in the ship and the holder change. Gas tankers also have the effect that energy is absorbed by the sloshing and rocking of the liquid, the liquid evaporates, and it is necessary to remove excess energy by additional cooling or other methods.
Hereinafter, the term (liquefied natural gas) LNG tanker means a gas tanker for storage and / or transport of liquefied gas.

  These effects make it impossible to fully utilize the capacity of the container and reduce the overall filling rate to a value between 10% and 75%. This results in operational limitations, especially for LNG shuttle tankers operating in the spot market. If these shuttle tankers cannot land or load a commercially favorable or operationally necessary amount of gas, for example because they cannot be moored to a buoy due to the surrounding sea conditions, This is because the opportunity is lost. Also, in the development of oil and gas fields where LNG tankers are used as floating storages near the borehole, it is preferable to realize the maximum capacity in water waves or swells as stably as possible. LNG tankers are also used for so-called “regasification”. Regasification uses ambient heat to evaporate liquid (natural) gas and deliver the gas to the customer.

  The liquid gas constitutes a vapor-liquid equilibrium in the holder depending on temperature and pressure. The pressure and temperature are selected so that under atmospheric conditions, the gas in the holder is essentially present as a boiled liquid. Therefore, the empty space on the liquid is completely filled with the vapor or gas of the liquid product.

Patent Document 1 discloses an inflatable material that can be used as a roof or lid floating in an open digestion tank filled with water.
The roof of the digestion tank has a metal tube in the center. The bottom of the central tube opens into the digestion tank and collects the biogas formed there. The upper surface of the central tube is equipped with a pressure relief valve and a downstream passage to continuously process digestion gas collected by a gas combustion device or another gas processing device. This roof is not suitable to be inserted into a (existing) holder of liquefied gas to serve as a shock absorber for liquid gas vibration during transport.

Inflate bags, airbags, cushion cushions or balloons inside the holder of the transport or storage device and pressurize them with inflation gas such as nitrogen or air, for example by using inflation gas from a compressor or high pressure storage tank Is known.
This causes the balloon to occupy most of the empty space in the holder, thus limiting liquid sloshing and vapor formation. Preferably, this inflatable material creates a form and / or force that connects and closes to the inner wall of the holder, thereby obtaining a good cushioning effect against the liquid movement or rocking movement. An inflatable material configured in a suitable embodiment comprises an accordion wall or other wall or walls that can be stretched or folded, and by supplying inflation gas to or expelling the inflation material. Each wall folds inward and outward, or stretches and contracts. This type of expansion material is not suitable for insertion into the holder of an LNG tanker. This is because the liquid and vapor must maintain contact in order to be able to cool and discharge the vapor.

U.S. Pat. No. 3,120,902

  An object of the present invention is to provide an inflatable material. With this expansion material, even if the entire vacant space is not necessarily filled with the expansion material, rocking or sloshing of liquid such as liquefied gas in the (transport) holder is suppressed and greatly reduced.

  The present invention provides an inflatable material having a thickness less than the height between the free liquid level and the holder upper wall of the holder, whereby the object is realized. The inflatable material includes an opening extending from the material bottom wall to the material top wall, and the opening constitutes an open fluid connection between the liquefied gas and the vapor gas.

  Using the method described above, the evaporating liquid flows into the vapor space by the fluid connection formed by the opening of the expansion material, and the condensed gas can be returned to the liquefied gas, while the expansion material on the liquid surface The rocking and sloshing of the liquid is suppressed.

  In a preferred embodiment, the inflatable material comprises a friction flap or stable body near the holder sidewall. This feature allows the expanded material to gain more stability at its ends without having to create a new resistance while the material changes position due to changes in the liquid level.

  Preferably, the inflatable material comprises a friction flap or stable body near the four opposing holder sidewalls of the holder. Specifically, the stable body extends around the entire periphery of the inflatable material and constitutes an integral circumferential body. By attaching a friction flap to each of the four opposing holder sidewalls and providing a stable body in one piece, the inflatable material cannot easily move up or down along the holder sidewalls, thereby Providing the expansion material with a stabilizing effect and a buffering effect against vibration of liquid.

  Preferably, in the use position, the material bottom wall is essentially flat and the material top wall is arcuate, curved or multiple arcuate or curved. Thereby, the liquid vibration is further suppressed, so that the deformation of the expansion material caused by the movement of the liquid in the holder is less likely to occur.

  Embodiments in which the friction flap is an expansion body or material with a closed interior space for enclosing the inflation gas are preferred. In these methods, an increased friction surface is formed between the friction flap and the holder inner wall by thickening or widening the friction flap horizontally and / or by lengthening the friction flap vertically. The amount of friction or resistance between the friction flap and the holder inner wall can be adjusted.

  Specifically, the connection passage is provided between the internal space of the friction flap and the internal space of the expansion material. As the pressure in the interior space of the inflatable material increases, the friction flap becomes longer and thicker due to this connecting passage.

  Preferred is an embodiment in which the connecting passage is an elongated slit and forms an open fluid connection between the inflation material and the friction flap. As a result, a good liquid connection is formed between the expansion material and the friction flap. Thereby, the clamping force exerted by the expansion material on the vertical wall of the holder can be maintained while the stable frictional force between the friction flap and the holder wall is maintained.

  In an alternative embodiment, a support material is provided that extends from the material top wall of the expanded material to the holder top wall of the holder. Specifically, the support material is an expansion material, and the height can be adjusted by supplying or discharging expansion gas. These support materials hold the expanded material in position on the liquid surface, thereby suppressing liquid vibration. The support material can be stretched or retracted, for example by supplying or exhausting inflation gas, and the vertical position of the inflation material can be adapted to the degree of filling of the holder.

  In a first alternative embodiment, the friction flap features a substantially horizontal flexible flap. The flexible flap is connected to the material side wall of the inflatable material by a rotation point or bending point. Specifically, the flexible flap is manufactured from a strong elastic material such as rubber or plastic material. In this embodiment, it is possible to provide a closure between the inflatable material and the holder wall. The closure can easily move along a protruding portion of the holder wall, such as a wall bend / twist or a wall tip in a “membrane” type gas tanker.

  A second alternative embodiment of the friction flap is characterized in that the friction flap is a flexible roll. The flexible roll is mounted to rotate about the axis of rotation on the material side wall of the inflatable material. Specifically, the flexible roll is manufactured from a flexible and compressible material, such as a sponge material and / or a fiber material such as hair. When a protruding portion of the wall, such as a wall bend / twist or tip, pushes the roll stock together, the roller rotates about its axis. This makes it easier to move the inflatable material upward and downward, without damaging the walls and / or the inflatable material.

  The invention also relates to a transport or storage device comprising a container having an inflatable material.

LNG tanker perspective view with a small number of holders for liquefied gas Detailed view of the holder of FIG. 1 with inflatable material Top view showing a holder with an inflatable material having an opening Detailed view of the friction flap near the holder sidewall Side view of an alternative embodiment of an inflatable material with a support material 5A is a perspective view of the support material of FIG. 5A. Top view of the embodiment of FIG. 5A Illustration of an alternative embodiment of a friction flap Illustration of an alternative embodiment of a friction flap Illustration of an alternative embodiment of a friction flap Explanatory drawing which shows the roll flap which is 2nd alternative embodiment of a friction flap.

  The present invention is illustrated by an illustration of an inflatable material and several embodiments, thereby revealing features and other advantages.

FIG. 1 shows a transport or storage device with a small number of holders 2.
The transport apparatus of this example is a gas tanker 1 and includes eight holders 2 or tanks provided for transporting liquid cargo 3. In this example, the liquid cargo 3 is a liquefied gas such as LNG (liquefied natural gas). A gas tanker suitable for transporting liquefied gas is hereinafter referred to as an LNG tanker. The LNG tanker has means and functions for maintaining the gas in a liquefied state by maintaining the correct temperature and pressure.

In FIG. 2, the holder 2 is shown in detail.
The holder 2 stores a liquefied gas, such as natural gas or LNG, with its vapor and optionally forms a closed space for transport. The closure holder has a holder bottom wall, a holder top wall 31 and holder side walls 9 ', 9 ", 10', 10". The liquefied gas 3 is filled up to about three-fourths of the holder 2, and the upper surface of the liquid is located at a height of about three-fourths of the holder 2. An inflatable material, that is, an airbag 4 having a material wall 5 floats above the liquid 3 to define a sealed internal space 6. The material wall 5 is formed by a flat material bottom wall 7, a material upper wall 8 having a plurality of curves, and a material side wall 13. Friction flaps 20 ', 20 "are provided on the material side wall 13 and are in close contact with the holder side walls 9', 9", 10 ', 10 "of the holder 2. The expansion material 4 has a thickness d. This thickness d is smaller than the height between the free liquid level and the holder upper wall 31 of the holder 2. Thereby, the expansion material 4 occupies only a small part of the vapor space of the holder. , Connected to expansion assisting means (not shown) such as an air compressor and a control unit, whereby an expansion gas such as air or another gas can be taken in and out of the expansion material 4. Control of a control lamp or the like Means are also provided in the control room or area of the gas tanker.

  The inflatable material 4 of FIG. 2 includes an opening 11 that extends from the material bottom wall 7 to the material top wall 8. Thereby, the opening 11 constitutes an open fluid connection between the liquefied gas and the vapor gas. The gas phase is in wide contact with the liquid phase through these openings 11. Thereby, the vaporized liquid can escape through the expansion material 4, or the condensed vapor is returned to the liquid. In such a holder 2 containing liquefied gas at a temperature much lower than the ambient temperature, heat conduction to the holder 2 absorbs energy in the form of heat as a result of rocking and sloshing of the liquid in the holder. Energy is lost. By buffering liquid stabilization and liquid vibrations, energy is restricted from flowing out to the holder 2 and energy consumption is reduced.

In the top view of the holder 2 in FIG. 3, an expansion material 4 having an opening 11 is shown.
The number of openings 11 may vary in number and size, and in general it can be said that it is advantageous to arrange these openings 11 regularly on the material upper wall 8.

4 shows a cross section IV-IV of FIG.
The details of the expansion material 4 and the wall material 5 formed from the material top wall 8 and the material bottom wall 7 in the present embodiment are shown. A portion of the material wall 5 may comprise a reinforcing material such as a woven fiber net or a carrier. The material bottom wall 7 is preferably provided with reinforcements to prevent distortion and maintain a flat surface. This is advantageous for suppressing the vibration of the liquid 3. In order to make the material upper wall 8 of the expansion material 4 into a regular, longitudinally extending curved surface, the expansion material includes a connecting part 12 between the material upper wall 8 and the material bottom wall 7. The inflatable material 4 has a thickness d. The thickness d is shorter than the distance between the liquid level and the holder upper wall 31 of the holder 2.

  4 further shows a friction valve 20 ″ implemented as an expansion body with an internal space 21. Along with the friction wall 23, the friction flap 20 ″ extends parallel to the holder side wall 10 ″. The friction wall 23 is the holder side wall. It contacts the inner side 19 of 10 ″ and is preferably fixed. As a result, a frictional force is generated between the holder side wall and the friction flap 20 ″ and the expansion material 4 attached to the friction flap 20 ″. Thereby, the expansion material 4 acts as a shock absorber for liquid vibration. This is because the expansion material 4 is stably disposed on the liquid surface, thereby preventing the occurrence of liquid vibration and suppressing the liquid vibration. The friction flaps can be attached to one, two, or all four of the material side walls of the expansion material 4, or can be configured as a body that extends around the entire periphery of the expansion material 4. The amount of resistance between the holder side wall and the friction flap can be adjusted by adjusting the amount of air in the internal space 21 of the friction flap.

  The friction flaps 20 ′, 20 ″ may comprise individual expansion means or may be provided by a control system. Advantageously, the internal space 21 of the friction flaps is open to the internal space 6 of the expansion material 4. The friction of the wall of the holder 2 can be changed at the same time by expanding or contracting the expansion material, so that the connection passage 22 is connected to the internal space 6 of the expansion material 4 and the friction flap 20 ′, It is provided between the internal space 21 of 20 ″. In a special embodiment, the connecting passage 22 is formed as an elongated slit and extends parallel to a substantial part between the inflatable blank 4 and the friction flaps 20 ', 20 ". The friction flaps 20', 20" , Sometimes called lid or wing.

  Although the expansion material 4 floats on the liquid surface of the liquid cargo 3, but does not occupy the entire vapor space, the expansion material 4 functions as a buffer device for liquid vibration, and suppresses or slows down the formation of liquid vibration. And has a buffering effect against the rocking or sloshing movement of the liquid 3 in the holder 2. This buffering effect can be enhanced by further inflating the inflatable blank 4 so that the friction flap 20 'spreads until it comes into contact with the inside 19 of the holder side wall 10 "of the holder 2. In this inflated position, The internal space 21 of the friction flap 20 ′ is also completely filled with inflated air, so that friction occurs between the holder side wall 10 ″ and the friction flap 20 ′, and the expansion material is resistant to liquid vibrations in the holder 2. Has a buffering effect.

In the alternative embodiment of FIGS. 5A, 5B, 5 C, the friction flaps 20 ′, 20 ″ of the expansion material 4 ′ with the thickness d and the through-opening 11 are replaced by the support material 30.
The support material 30 extends from the material upper wall 8 of the expansion material 4 ′ to the holder upper wall 31 of the holder 2. These support materials 30 also maintain the expanded material 4 ′ in a position on the surface of the liquid 3, which also suppresses liquid vibration. The support material 30 is preferably stretchable and retractable, so that the vertical position of the expansion material 4 ′ can be adapted to the degree of filling of the holder 2. To that end, the support material 30 preferably comprises a separate system for controlling, supplying and discharging the expanded air. The support material may include a bellows wall for easily stretching and storing the support material 30.

6A, 6B, 6C show a first alternative embodiment of a friction flap suitable for application to a “membrane” type holder 2.
This holder 2 has a thin membrane wall 45. These membrane walls 45 may have bends 46 or bellows structures or may have protruding tips that overlap the membrane. Thereby, it is possible to compensate for expansion and contraction of the wall material due to a large temperature difference. These protruding bends or tips 46 are disadvantageous for the operation of the inflatable material according to the invention. Therefore, the expansion material 4 ″ of the present embodiment includes the flexible flap 40, and the flexible flap 40 is disposed on the material side wall 13 of the expansion material 4 ″ by the pivot 41.

  In FIG. 6A, the expansion material 4 ″ and the flexible flap 40 move downward with respect to the liquid level in the holder 2. The flexible flap 40 shown in FIG. Slightly tilted about the pivot point 41 with respect to the expansion material 4 ″.

  In FIG. 6C, after the flexible flap 40 of the expansion material 4 ″ has moved upward, it is inclined downward to this extent around the pivot point 41 with respect to the material side wall 13 of the expansion material 4 ″. The flap 40 moves along and beyond the wall bend 46. During the upward and downward movement of the inflatable material, the flexible flap 40 is in a good tight seal with the membrane wall 45 of the holder, providing a fixed position for the inflatable material 4 ″ that prevents liquid sloshing and provides suppression.

In a second alternative embodiment of the friction flap of FIG. 7, a flexible roll 50 is applied.
The flexible roll 50 rotates around the rotation shaft 51 and is attached to the material side wall 13 of the expansion material 4 ′ ″. The axis of rotation is connected to the inflatable material 4 '''in a known manner such as a clamp or similar means. The flexible roll or roll flap 50 is manufactured from a flexible, compressible material such as a sponge-like material or loose fibers such as hair. The roll flap 50 can easily pass through the obstacle protruding from the membrane wall 45 because the material of the roll pushes together the location of the obstacle such as the wall bend or the tip 46. The flexibility of the material of the flexible roll 50 expands to the mechanical strength of the membrane wall 45, or to the membrane mounted thereon, or to prevent liquid sloshing or buffer fluid sway. The material easily adapts to the need to exercise the clamping force.

  The inflatable material 4, 4 ′, 4 ″, 4 ′ ″ may be a single large interior space with a thickness d, or may be partitioned into compartments such as a partial material attached in the longitudinal direction of the holder. May be.

  The inflatable material can be loosely inserted into the holder or can be fixedly attached to the holder, but preferably the material is placed in the holder so that a small force is exerted on the holder side wall of the holder The

  The inflatable material can be made from any suitable material such as plastic or cloth.

Claims (15)

An expansion material used as a buffer device for liquid vibration inside the holder (2),
The holder is a closed space, suitable for storing liquid cargo (3), the holder is suitable for transporting a liquefied gas, such as liquefied natural gas LNG, with its vapor;
The closed holder comprises a holder bottom wall, a holder top wall (31), and a holder side wall (9 ′, 9 ″, 10 ′, 10 ″),
The inflatable material (4) comprises a material wall (5) defining a closed internal space (6) with a fixed volume containing inflation gas, the material wall (5) comprising a material bottom wall (7); A material upper wall (8) and a material side wall (13);
In the use position, the expansion material floats with the material bottom wall (7) in contact with the free liquid surface of the liquid cargo (3),
The expansion material (4) has a thickness (d), and the thickness (d) is smaller than a height between the free liquid level and the holder upper wall (31) of the holder, (4) includes an opening (11) extending from the material bottom wall (7) to the material top wall (8), and the opening (11) is an opening fluid between the liquefied gas and the vapor gas. configure the connection,
The expansion material (4) is connected to expansion assisting means for supplying or discharging the expansion gas to or from the expansion material (4), as a liquid vibration damping device inside the holder (2) Inflatable material to use. The inflatable material according to claim 1, wherein the inflatable material (4) comprises a friction flap or a stable body (20 ', 20 ") in the vicinity of the holder side wall (9', 10 '). The inflatable material (4) has a friction flap or stable body (20 ', 20 ") in the vicinity of four opposing holder sidewalls (9', 9", 10 ', 10 ") of the holder (2). The expansion material according to claim 2 provided. The inflatable material according to claim 3, wherein the stable body (20 ', 20 ") extends around the entire periphery of the inflatable material (4) and constitutes an integral circumferential body. 5. Inflation according to any of claims 1 to 4, wherein in the use position, the material bottom wall (7) is essentially flat and the material top wall (8) is arcuate, curved or multiple arcuate or curved. Material. The expansion material according to any one of claims 2 to 4, wherein the friction flap (20 ', 20 ") is an expansion body or a material having a closed internal space (21) for containing an expansion gas. The connection passage (22) is provided between the internal space (21) of the friction flap (20 ', 20 ") and the internal space (6) of the expansion material (4). Inflatable material. The inflatable material according to claim 7, wherein the connecting passage (22) is an elongated slit and forms an open fluid connection between the inflatable material (4) and the friction flap (20 ', 20 "). The expansion material according to claim 1, wherein a support material (30) extending from the material upper wall (8) of the expansion material (4 ') to the holder upper wall (31) of the holder (2) is provided. The expansion material according to claim 9, wherein the support material (30) is an expansion material, and the height thereof can be adjusted by supplying or discharging an expansion gas. The said friction flap is a substantially horizontal flexible flap (40), It connects to the raw material side wall (13) of the said expansion | swelling raw material (4 '') by a rotation point or a bending point (41). Inflatable material. The inflatable material according to claim 11, wherein the flexible flap (40) is manufactured from a strong elastic material such as rubber or plastic material. The friction flap is a flexible roll (50), and is mounted on the material side wall (13) of the expansion material (4 ''') so as to rotate around a rotation axis (51). Expansion material as described in The inflatable material according to claim 13, wherein the flexible roll (50) is manufactured from a flexible and compressible material, such as a sponge material and / or a fiber material such as hair. A transport or storage device (1), characterized in that it comprises a container (2) comprising an inflatable material (4, 4 ', 4 ", 4'") according to any one of the preceding claims.

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