JP5242217B2 - Flexible tube for cryogenic fluid transport - Google Patents

Description

  The present invention relates to a flexible tube for transporting a cryogenic fluid used for transporting a fluid such as liquefied natural gas having a cryogenic temperature from an offshore floating facility installed on the sea to a tanker or the like.

  Conventionally, floating oil facilities and tankers, etc., have been used floating floating facilities and tankers in order to load them into transport tankers from offshore floating facilities (bases) that store oil calculated from offshore oil fields, etc. Are connected, and oil is transported. As a flexible tube for transporting a fluid at room temperature such as petroleum, a resin tube is usually used. As such a resin-made flexible tube for transporting fluid, there is a flexible fluid-transporting tube having a reinforcing layer, a heat insulating layer, a waterproof layer, and the like on the outer peripheral portion of the resin-made inner tube (Patent Document 1).

On the other hand, natural gas calculated from a gas field on the ground or in the near sea is liquefied and stored at the base. When loading liquefied natural gas (hereinafter “LNG”) onto a tanker for transportation, an articulated loading arm or the like provided at a coastal base is used. As the LNG receiving base, for example, there are an LNG receiving base and an LNG shipping base system described in Patent Document 1 adopting a loading arm system (Patent Document 2).
Japanese Patent Laid-Open No. 5-180375 JP-A-5-65718

  However, although the loading arm method as in Patent Document 2 can be loaded from a ground base into a tanker, the LNG is loaded into a tanker from a floating facility that produces and stores LNG installed in a gas field in the open sea. In this case, there is a problem that the loading arm cannot follow the movement between the facility and the tanker, which are greatly shaken by waves, winds, etc., and the size of the equipment is increased.

  Further, in the conventional method of transporting oil, a method of loading a fluid into a tanker using a resin floating flexible tube as in Patent Document 1 is difficult to cope with a cryogenic fluid such as LNG. There is a problem that. This is because LNG has an extremely low temperature of about -160 ° C, so the conventional resin-type floating flexible tube is brittle at such an extremely low temperature, so that sufficient flexibility cannot be obtained and embrittlement occurs. This is because the flexible tube is broken by the pressure for pumping LNG. Therefore, there is a demand for a flexible tube that has both durability and heat insulation that can be used even at extremely low temperatures, but there is no floating flexible tube that can use a cryogenic fluid such as LNG for transportation over the sea. There is a problem.

  In particular, when a heat-insulating material with little flexibility is used, there is a possibility that when the flexible tube is bent, the heat-insulating material may be damaged due to contact with each other and a high heat-insulating effect may not be maintained. There is.

  The present invention has been made in view of such problems, and is a flexible tube used when loading a fluid from an offshore floating facility to a tanker, and enables transport of a cryogenic fluid such as LNG. It aims at providing the flexible tube which has the heat insulation layer which is excellent in the heat insulation characteristic and can follow the flexibility of a flexible tube.

In order to achieve the above-described object, the present invention provides at least a flexible corrugated metal inner tube, a reinforcing layer provided on an outer peripheral portion of the corrugated metal inner tube, and an outer peripheral portion of the reinforcing layer. A heat insulating layer provided on the outer peripheral portion of the heat insulating layer, and the heat insulating layer has a plurality of vacuum heat insulating members, and between the adjacent vacuum heat insulating members. gap is provided, the heat insulation layer, said vacuum insulation member is formed by stacked plurality, wherein the inter-vacuum insulation member, characterized Rukoto sliding layer is provided for sliding the vacuum heat insulating members together It is a flexible tube for cryogenic fluid transport. In this case, the sliding layer is preferably a layer around which any of a resin tape, a nonwoven fabric tape, and an oil-impregnated paper tape is wound.

  The width of the gap is desirably 8% or more of the width of the vacuum heat insulating member.

  The vacuum heat insulating member preferably includes an outer packaging material having a metal layer, and a heat insulating material filled in the outer packaging material, and the inside of the outer packaging material is preferably decompressed and sealed. The heat insulating material is preferably a continuous urethane foam.

  Here, the cryogenic fluid refers to a fluid of about −160 ° C. or lower, such as LNG.

  According to the present invention, since the heat insulating layer is formed by the vacuum heat insulating member, the heat insulating effect between the fluid flowing in the corrugated metal inner pipe and the outside is very high, and a gap is provided between the vacuum heat insulating members. Therefore, even when the flexible tube is bent, adjacent vacuum heat insulating members do not come into contact with each other, and therefore, a cryogenic fluid having a heat insulating layer capable of following the flexibility of the flexible tube. A flexible tube for transportation can be obtained. Moreover, if the space | interval of vacuum heat insulation members shall be 8% or more of the width | variety of a vacuum heat insulation member, even in the minimum bending radius of a flexible tube, vacuum heat insulation members will not contact.

  Further, the vacuum heat insulating member is filled with a heat insulating material, and particularly when the continuous urethane foam is filled, the heat insulating effect is particularly excellent. In addition, if a sliding layer is provided between the vacuum heat insulating members, the vacuum heat insulating members easily slip when the flexible tube is bent, so that the heat insulating layer can reliably follow the flexibility of the flexible tube. Can be obtained.

  According to the present invention, it is a flexible pipe for transporting a cryogenic fluid used when loading a fluid from an offshore floating facility to a tanker, and is suitable for transporting a cryogenic fluid such as LNG, and has excellent heat insulation characteristics, A flexible tube having a heat insulating layer capable of following the flexibility of the flexible tube can be provided.

  Hereinafter, the flexible tube 1 concerning embodiment of this invention is demonstrated. FIG. 1 is a perspective view showing the configuration of the flexible tube 1, FIG. 2 (a) is a partial sectional view of the flexible tube 1, and FIG. 2 (b) is an enlarged view of a portion A of FIG. 2 (a). . The flexible tube 1 mainly includes a corrugated tube 3, a floor layer 5, a reinforcing layer 7, a heat insulating layer 15, a waterproof layer 13, and the like.

  The innermost layer of the flexible tube 1 is provided with a corrugated tube 3 as an inner tube. When the flexible tube 1 is used, a fluid (hereinafter described as a flow of LNG) flows through the corrugated tube 3. The corrugated tube 3 is a flexible tube, has a certain degree of strength, and has excellent low-temperature resistance. That is, it is preferable to use a material that can maintain flexibility even when a cryogenic fluid such as LNG flows therein, and is less likely to crack or crack. The corrugated tube 3 is, for example, a metal corrugated tube, and preferably a stainless bellows tube. It should be noted that instead of the corrugated tube 3, other types of inner tubes can be used as long as they have the same flexibility and excellent low-temperature resistance.

  A floor layer 5 is provided on the outer peripheral portion of the corrugated tube 3. The floor layer 5 is a layer for leveling the irregularities on the outer periphery of the corrugated tube 3 (unevenness due to the corrugated shape), and can be deformed following the flexibility of the corrugated tube 3. That is, the floor layer 5 has a certain thickness and serves as an uneven cushion due to the corrugated shape of the outer periphery of the corrugated tube 3. However, it is not necessary to completely fill the recess. The outer peripheral portion of the corrugated tube 3 is further provided with a reinforcing layer 7 and the like which will be described later. However, it is difficult to wind the reinforcing tape or the like constituting the reinforcing layer 7 due to the unevenness of the outer peripheral surface of the corrugated tube 3. This is to prevent the reinforcing tape from being displaced during use.

  In addition, as the floor layer 5, a nonwoven fabric etc. can be used, for example. Also, if the outer peripheral surface of the inner tube has no large unevenness due to corrugation or the like, or if it has unevenness, it will not adversely affect the reinforcing layer 7 provided on the outer peripheral portion. The floor layer 5 is not necessary.

  A reinforcing layer 7 is provided on the outer periphery of the floor layer 5. The reinforcing layer 7 can be deformed following the flexibility of the corrugated tube 3 while suppressing the corrugated tube 3 from deforming (extending) mainly in the axial direction of the flexible tube 1. For example, when LNG is caused to flow into the corrugated tube 3, an internal pressure of about 1 MPa is generated inside the corrugated tube 3. The corrugated tube 3 can withstand the pressure on the inner peripheral surface of the corrugated tube 3, but the corrugated shape provided in order to obtain flexibility facilitates the internal pressure in the axial direction of the corrugated tube 3. Deforms (stretches). For this reason, the reinforcing layer 7 is provided in order to suppress the axial deformation of the corrugated tube 3.

  The reinforcing layer 7 is formed of a reinforcing tape such as a fiber tape or a metal tape. As the fiber tape, for example, a polyester fiber woven tape, an aramid fiber woven tape, an arylate fiber woven tape, an ultra high molecular weight polyethylene fiber woven tape, a carbon fiber woven tape, and the like can be used. Moreover, as a metal tape, a stainless steel tape etc. can be used, for example.

  In order to form the reinforcing layer 7, a reinforcing tape is wound around the outer periphery of the floor layer 5 at a predetermined pitch. When winding the reinforcing tape, the end portions in the width direction of the reinforcing tape do not need to overlap each other, that is, the winding pitch of the reinforcing tape may be larger than the width of the reinforcing tape. The reinforcing tape is overlapped at least twice and wound around the floor layer 5 so that the winding direction of the first reinforcing tape and the winding direction of the second reinforcing tape are opposite to each other. That is, the respective double-wrapped reinforcing tapes are wound around the outer periphery of the floor layer 5 so as to cross each other (this winding method is referred to as “alternate winding”).

  The reason why the reinforcing tape is wound only from one direction is that when the flexible tube 1 receives a force in the axial direction, a twisting force is generated on the flexible tube 1 according to the winding direction of the reinforcing tape. is there. If necessary, a pressing tape layer of the reinforcing tape (not shown) may be further provided on the outer periphery of the wound reinforcing tape. For example, a nonwoven fabric tape can be used as the presser winding layer, and the nonwoven fabric tape may be wound around the outer surface of the alternately wound reinforcing tape or the outer peripheral surface of each winding layer.

  A heat insulating layer 15 is provided on the outer periphery of the reinforcing layer 7. The heat insulating layer 15 insulates the LNG flowing in the corrugated tube 3 from the outside of the flexible tube 1 and can be deformed following the flexibility of the corrugated tube 3. The heat insulating layer 15 is composed of a plurality of vacuum heat insulating members 9a, 9b,. For example, as illustrated in FIG. 2B, vacuum heat insulating members 9 a and 9 b having a heat insulating member width 23 are wound around the outer peripheral portion of the reinforcing layer 7. A gap 11a having a gap width of 25 is formed between the vacuum heat insulating members 9a and 9b and is wound with a gap therebetween. That is, the vacuum heat insulating members 9 a and 9 b are located in the lowermost layer (first layer) of the heat insulating layer 15. Note that. The configuration of the vacuum heat insulating member 9 will be described later.

  The vacuum heat insulating members 9c and 9d are wound around the outer peripheral portions of the vacuum heat insulating members 9a and 9b wound around the lowermost layer. A gap 11b having a gap width of 25 is formed between the vacuum heat insulating members 9c and 9d and is wound with a gap therebetween. That is, the vacuum heat insulating members 9c and 9d form a second layer that is the outermost layer of the lowest layer. The gap 11a formed in the lowermost layer and the gap 11b formed in the second layer are displaced in the length direction of the flexible tube 1, and the gaps are not connected.

  Similarly, the vacuum heat insulating member 9e is wound around the outer peripheral portion of the vacuum heat insulating members 9c and 9d while forming a gap 11 between adjacent vacuum heat insulating members (not shown) (third layer). Further, vacuum heat insulating members 9f and 9g are overlapped and wound around the outer periphery of the vacuum heat insulating member 9e (fourth layer, fifth layer).

  In each layer, a gap 11 is provided between the vacuum heat insulating members 9, but the gaps 11 provided in adjacent layers are provided with their positions shifted in the length direction of the flexible tube 1. . That is, the gaps 11 are not connected to each other. For this reason, the gap 11 is not continuous, and the heat insulating effect of the vacuum heat insulating member 9 can be effectively obtained. Moreover, although the heat insulation layer 15 of the flexible tube 1 is provided by stacking five layers of the vacuum heat insulation member 9, the winding of the vacuum heat insulation member 9 is not limited to five layers. That is, it can be determined as appropriate according to the specifications required for the flexible tube 1.

  The heat of the LNG flowing through the corrugated tube 3 is hardly transmitted to the outer surface of the flexible tube 1 by the heat insulating layer 15. For this reason, the waterproof layer 13 which is the outermost layer described later is not affected by the temperature of the LNG. Similarly, the external temperature of the flexible tube 1 is not transmitted to the LNG, and the LNG is prevented from vaporizing in the flexible tube 1.

  A waterproof layer 13 is provided on the outer periphery of the heat insulating layer 15. The waterproof layer 13 can be deformed following the flexibility of the corrugated tube 3 while preventing water from entering from the outside. That is, when the flexible tube 1 is floated on the sea and LNG is transported, seawater or the like does not enter the flexible tube 1. The waterproof layer 13 is made of resin, for example, and is preferably made of polyethylene. As described above, the heat-insulating layer 15 hardly affects the waterproof layer 13 due to the temperature of LNG, which is a very low temperature. For this reason, the waterproof layer 13 does not become brittle when the temperature becomes low, and cannot follow the flexibility of the corrugated tube 3.

  Next, the structure of the vacuum heat insulating member 9 will be described with reference to FIG. FIG. 3 is a cross-sectional view of the vacuum heat insulating member 9. The vacuum heat insulating member 9 is mainly composed of an outer packaging material 17, a filler 19, a getter 21, and the like. The vacuum heat insulating member 9 is a sheet-like or tape-like member having a thickness of about 2 mm.

  As the filler 19, a heat insulating material such as a resin member can be used. A particularly effective material is a porous material called continuous urethane foam. The continuous urethane foam preferably has a cell diameter of 100 μm or less. For example, when a continuous urethane foam having a cell diameter of 100 μm is used, the pressure in the filling portion has a very high heat insulating effect due to the degree of vacuum of about 0.5 Torr. In this case, the thermal conductivity is about 1 / 2.5 compared to a general polyurethane heat insulating material, and the vacuum heat insulating member 9 having extremely high heat insulating characteristics can be obtained. Moreover, since the vacuum heat insulating member 9 using a continuous urethane foam has a compressive strength of 1.4 times or more compared with the urethane foam heat insulating material, even if it is used for the flexible tube 1, the thickness is reduced inside. There is nothing.

  The outer packaging material 17 wraps the filler 19 and blocks ventilation between the outside and the inside. As the outer packaging material 17, it is only necessary to block the ventilation between the inside and the outside of the vacuum heat insulating member. For example, a gas barrier laminate film including a metal foil is desirable.

  The getter 21 is for adsorbing a small amount of gas entering from the outside, and is provided as necessary. As the getter 21, synthetic zeolite, activated carbon, or the like can be used.

  Next, the state of the vacuum heat insulating member 9 when the flexible tube 1 around which the vacuum heat insulating member 9 is wound will be described. 4A and 4B are schematic views showing the vacuum heat insulating member 9 wound around the flexible tube 1. FIG. 4A shows a state in which the flexible tube 1 is straight, and FIG. Is a deformed state. In FIG. 4, illustration of other layers such as the inner tube is omitted.

  When the diameter of the flexible tube 1 is D, the vacuum heat insulating member 9 can be regarded as being wound around a tube body having a diameter of approximately D with the center 27 of the flexible tube 1 as the center. As described above, the gap 11 is provided between the adjacent vacuum heat insulating members 9.

  The minimum bending radius R of the flexible tube 1 is usually about 7 times the diameter D of the flexible tube 1. When the flexible tube 1 is bent, the inside of the bending deformation of the flexible tube 1 becomes compression deformation and the outside becomes tensile deformation. At this time, the gap 11 between the vacuum heat insulating members 9 inside the bending deformation of the flexible tube 1 becomes smaller and the outer side becomes larger. If the ends of the vacuum heat insulating member 9 come into contact with each other, the vacuum heat insulating member 9 may be damaged. Therefore, even when the flexible tube 1 is deformed with the curvature of the minimum bending radius R, a gap width is required so that the vacuum heat insulating members 9 do not contact each other.

  Here, the amount of deformation inside the flexible tube 1 when the flexible tube 1 is deformed at the minimum bending radius R, and the relationship between the heat insulating member width 23 and the gap width 25 is (R−0.5D) / R = w / (w + g).

  Here, D is the diameter of the flexible tube 1, R is the minimum bending radius of the flexible tube 1, w is the heat insulating member width 23, and g is the gap width 25.

  Usually, the minimum bending radius R of the flexible tube is about 7 times the diameter D of the flexible tube. When the minimum bending radius R is 7 times the diameter D of the flexible tube 1, g = 0.0775 w from Equation 1.

  Therefore, when the flexible tube 1 is straight and the gap width 25 is about 8% or more of the heat insulating member width 25 which is the width of the vacuum heat insulating member 9, the flexible tube 1 is deformed with the minimum bending radius R. Even in this case, the vacuum heat insulating members 9 do not overlap each other. For this reason, it is desirable that the gap 11 between the vacuum heat insulating members 9 has a width of 8% or more of the width of the vacuum heat insulating member 9.

  Normally, a tanker of 100,000 to 150,000 tons class is used as a tanker used for fluid transportation at sea in consideration of fluid transportation efficiency. In addition, since the weather varies greatly on the sea, it is desirable that the operation of loading a fluid into a tanker or the like is usually completed within 24 hours. Therefore, considering the loading efficiency, the fluid velocity is 5 m / sec. Then, the diameter D of the flexible tube 1 is approximately 400 mm to 500 mm, and several of them are used simultaneously. However, the diameter D of the flexible tube 1 is preferably larger in order to increase the fluid transportation efficiency, but the allowable bending radius R of the flexible tube 1 is increased, and the laying device of the flexible tube 1 is enlarged. Therefore, the diameter of the flexible tube 1 is appropriately determined according to usage conditions and the like.

  FIG. 5 is a diagram illustrating a usage state of the flexible tube 1. An offshore floating facility 30 is provided on the sea. The offshore floating facility 30 is a storage base that is provided especially on the open sea and liquefies and stores the natural gas calculated from the seabed gas field. The LNG stored in the offshore floating facility 30 is periodically transported to the tanker 37.

  A supply unit 31 is provided on the offshore floating facility 30. The supply unit 31 is a part that sends out LNG stored in the offshore floating facility 30. On the other hand, the tanker 37 is provided with a receiving unit 35. The receiving unit 35 is a part that receives the LNG sent out from the supply unit 31.

  The flexible tube 1 is wound around the drum 39 and stored, and is sent out from the drum 39 to the sea when in use. On the sea, the end of the flexible tube 1 is guided to the tanker 37 by a small ship (not shown). After the flexible tube 1 is sufficiently sent to the sea, both ends of the flexible tube 1 are connected to the supply unit 31 and the receiving unit 35, respectively. While the flexible tube 1 floats on the sea, the LNG sent from the supply unit 31 is transported to the receiving unit 35, and the LNG is loaded from the offshore floating facility 30 to the tanker 37. At this time, since the flexible tube 1 has flexibility, it can follow relative positional fluctuations caused by waves between the offshore floating body facility 30 and the tanker 37 and is stored on the offshore floating body facility 30. Never take a place.

  As described above, according to the flexible tube 1 according to the present embodiment, the reinforcing layer 7 is provided on the outer peripheral portion of the corrugated tube 3 via the seat floor layer 5, so that the pressure of the fluid flowing inside It is possible to suppress the corrugated tube 3 from being deformed in the axial direction of the flexible tube 1. In addition, since the heat insulating layer 15 insulates the fluid in the corrugated tube 3 from the outside of the flexible tube 1, the fluid is not affected by the external temperature, and the waterproof layer 13 is formed depending on the temperature of the fluid. Not affected.

  Further, since the heat insulating layer 15 is composed of the vacuum heat insulating member 9, it is possible to obtain the flexible tube 1 having extremely high heat insulating characteristics. In particular, by stacking the vacuum heat insulating members 9, the flexible tube having higher heat insulating characteristics. 1 can be obtained. Moreover, since the thickness of the heat insulation layer 15 can be made thin, the flexible tube 1 which suppressed the increase in an outer diameter can be obtained.

  Further, since the gap 11 having the gap width 25 is provided between the adjacent vacuum heat insulating members 9, even when the flexible tube 1 is bent and deformed with the minimum bending radius R, the vacuum heat insulating members 9 are in contact with each other. There is no. Therefore, the vacuum heat insulating member 9 is not damaged.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, the configuration of the vacuum heat insulating member 9 is not limited to the configuration shown in FIG. If the decompressed space and the space are filled with a filler, the shape and the presence of the getter 21 and the like can be set as appropriate.

  Moreover, you may provide a sliding layer further between the vacuum heat insulation members 9 wound by overlapping. FIG. 6 is a view showing the flexible tube 40 provided with the sliding layer 41 (41a, 41b, 41c, 41d). As described above, when the flexible tube 1 is deformed, the vacuum heat insulating member 9 slips in the length direction of the flexible tube 1. Therefore, if the vacuum heat insulating members 9 do not slide smoothly, the deformation of the flexible tube 1 is hindered, and the vacuum heat insulating member 9 may be damaged when the flexible tube 1 is deformed. The sliding layer 41 is provided on one or both sides of the vacuum heat insulating member 9 and is a layer for improving the slip of the vacuum heat insulating member 9.

  The sliding layer 41 may be any material that has flexibility at low temperatures, a smooth surface, and good sliding properties. For example, a nonwoven fabric tape such as a polyester nonwoven fabric, a resin tape, an oil-paper tape, or the like can be used. As the tape used for the sliding layer, it is desirable to use a nonmetallic material having a large thermal resistance. In this case, heat transfer between the vacuum heat insulating members 9 can be prevented. The sliding layer 41 improves slippage between the vacuum heat insulating members 9, facilitates deformation of the flexible tube 1, and prevents the vacuum heat insulating member 9 from being damaged when the flexible tube 1 is deformed.

  The flexible tube 1 is not limited to LNG transportation. In addition, it can be used for transportation of various fluids.

The perspective view which shows the structure of the flexible tube 1. FIG. (A) is a fragmentary sectional view which shows the structure of the flexible tube 1, (b) is the A section enlarged view of (a). Sectional drawing which shows the structure of the vacuum heat insulation member 9. FIG. It is a schematic diagram which shows the state of the vacuum heat insulation member 9 when the flexible tube 1 deform | transforms, (a) is a state with the flexible tube 1 straight, (b) is a figure which shows the state with which the flexible tube 1 deform | transformed. The figure which shows the use condition of the flexible tube. The figure which shows the flexible tube 40 in which the sliding layer 41 was provided.

Explanation of symbols

1, 40 ...... Flexible tube 3 ...... Corrugated tube 5 ...... Seat floor layer 7 ...... Reinforcement layer 9 ...... Vacuum insulation member 11 ...... Gap 13 ...... Waterproof layer 17 …… ... outer packaging material 19 ... ... filler 21 ... ... getter 23 ... ... heat insulation member width 25 ... ... gap width 30 ... ... offshore floating body facility 31 ... ... supply part 35 ... ... receiving part 37 ... ... Tanker 39 ……… Drum 41 ……… Sliding layer

Claims (5)

A corrugated metal inner tube having at least flexibility;
A reinforcing layer provided on the outer periphery of the corrugated metal inner tube;
A heat insulating layer provided on the outer periphery of the reinforcing layer;
A waterproof layer provided on the outer periphery of the heat insulating layer;
Comprising
The heat insulating layer has a plurality of vacuum heat insulating members,
A gap is provided between the adjacent vacuum heat insulating members ,
The heat insulating layer is formed by stacking a plurality of the vacuum heat insulating members,
Wherein Between the vacuum heat insulating member, the cryogenic fluid transport flexible tube, characterized in Rukoto sliding layer is provided for sliding the vacuum insulation members to each other. 2. The flexible tube for transporting a cryogenic fluid according to claim 1 , wherein the sliding layer is a layer around which any one of a resin tape, a nonwoven fabric tape, and an oil immersion paper tape is wound. The flexible pipe for transporting cryogenic fluid according to claim 1 or 2, wherein a width of the gap is 8% or more of a width of the vacuum heat insulating member. The vacuum heat insulating member is
An outer packaging material having a metal layer;
A heat insulating material filled in the outer packaging material;
Comprising
4. The flexible tube for transporting a cryogenic fluid according to claim 1, wherein the outer packaging material is sealed under reduced pressure. The flexible pipe for transporting a cryogenic fluid according to claim 4 , wherein the heat insulating material is a continuous urethane foam.

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