Free falling guide rail for FSRU lifeboat

Abstract

An FSRU lifeboat free-falling guide rail is characterized in that a lifeboat frame is fixed to the part of a ship, the lifeboat frame is obliquely arranged, a lifeboat is fixed to the lifeboat frame, a falling guide rail obliquely extends downwards along the tail of the lifeboat frame, and the tail of the falling guide rail extends into water; the landing guide rail is composed of a straight section guide rail and a curved section guide rail, the straight section guide rail is in butt joint with the lifeboat frame, a gap exists between the straight section guide rail and the lifeboat frame, and rollers are laid on the surface of the straight section guide rail; the top endpoint of the curved guide rail is tangent to the straight guide rail, and the bottom endpoint of the curved guide rail and the horizontal plane form a 3-degree included angle. Truss type supporting frames are fixed to the lower surfaces of the landing guide rails and continuously arranged in the direction of the landing guide rails, and one ends of the supporting frames are fixed to the FSRU stern transom plate. When the lifeboat is released, the lifeboat is finally released into water in the direction forming an included angle of 3 degrees with the horizontal direction, free falling is completed, the lifeboat safely falls in a limited-water-depth sea area of a wharf, and the problems of collision with the seabed and casualties are avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of offshore FSRU design and construction, and particularly relates to a free-falling guide rail for FSRU lifeboat. BACKGROUND

[0002] Compared with onshore LNG receiving and gasification terminal, floating LNG receiving and gasification terminal (FSRU) is favored by more and more countries and regions due to its short construction period, low investment and environmental protection, and in recent years, orders have shown explosive growth.

[0003] FSRU needs to consider both navigation and terminal mooring conditions, making its life-saving design, especially lifeboat design, more difficult.

[0004] Lifeboats are divided into gravity type lifeboats and free-falling type lifeboats.

[0005] FSRU in navigation condition, whether gravity type lifeboat or free-falling type lifeboat, can meet the normal use of lifeboat in navigation condition according to the relevant requirements of SOLAS [1] [1] SOLAS, International Convention for the Safety of Life at Sea. [S], IMO. 2014.

[0006] But when FSRU is moored at the terminal for LNG receiving, gasification and natural gas transmission, neither gravity type lifeboat nor free-falling type lifeboat can be normally used, the reasons are as follows:

[0007] For gravity type lifeboat, affected by mooring cable distribution and narrow ship-shore distance, lifeboat is difficult to leave FSRU area after being launched;

[0008] For free-falling type lifeboat, the water depth of the terminal should be no less than 2 times the length of the lifeboat, and the water depth of most terminals cannot meet the requirement, so the lifeboat cannot be safely launched. SUMMARY

[0009] To solve the above problems, the present application proposes a free-falling guide rail for FSRU lifeboat, and the technical scheme adopted is:

[0010] A free-falling guide rail for FSRU lifeboat, a lifeboat frame is fixed on the ship, the lifeboat frame is inclined, the lifeboat is fixed on the lifeboat frame, a falling guide rail extends downward along the tail of the lifeboat frame, and the tail of the falling guide rail extends into water.

[0011] The landing guide rail is composed of a straight section guide rail and a curved section guide rail. The straight section guide rail is connected to the lifeboat rack, and there is a gap Lgap between the straight section and the lifeboat rack, 5mm≤Lgap≤20mm. The surface of the straight section guide rail is paved with rollers. The top end point of the curved section guide rail is tangent to the straight section guide rail, and the bottom end point of the curved section guide rail forms a 3° angle with the horizontal plane.

[0012] The vertical distance Hz between the top end point Pzt and the bottom end point Pzb of the straight section guide rail satisfies: Hz=H-Hqa.

[0013] Wherein, H is the distance from the top end point Pzt of the straight section guide rail to the sea surface.

[0014] Hqa is the distance from the top end point of the curved section guide rail to the sea surface.

[0015] The lower surface of the landing guide rail is fixed with a truss support frame. The support frame is continuously arranged along the direction of the landing guide rail, and one end of the support frame is fixed with the FSRU stern plate.

[0016] When releasing the lifeboat, the lifeboat slides downward along the lifeboat rack at an angle β; when sliding to the straight section guide rail part, the lowering direction of the lifeboat does not change (α=β); when sliding to the curved section guide rail, the lowering direction of the lifeboat gradually changes from the initial α to 3°, and finally the lifeboat is released into the water at an angle of 3° with the horizontal direction, completing the free falling of the lifeboat in the limited water depth of the wharf.

[0017] The above-mentioned FSRU lifeboat free falling guide rail is further provided with a part of the brachistochrone curve from the top end point of the curved section guide rail to the bottom end point of the curved section guide rail, satisfying the following formula:

[0018] x=k(θ-sinθ);

[0019] y=k(1-cosθ);

[0020] k is a scale factor, which is determined according to the length of the free falling lifeboat, 20m≤k≤25m.

[0021] θ is the curvature of any point on the curved section guide rail.

[0022] The above-mentioned FSRU lifeboat free falling guide rail is further provided with a part of the brachistochrone curve from the top end point of the curved section guide rail to the bottom end point of the curved section guide rail, satisfying the following formula:

[0023] The above-mentioned FSRU lifeboat free falling guide rail is further provided with a part of the brachistochrone curve from the top end point of the curved section guide rail to the bottom end point of the curved section guide rail, satisfying the following formula:

[0024] The vertical distance Hz between the top end point and the bottom end point of the straight section of the FSRU lifeboat free-falling guide rail satisfies Hz=H-Hqa.

[0025] H is the distance from the top end point of the straight section to the sea surface, and Hqa is the distance from the top end point of the curved section to the sea surface.

[0026] The bottom end point of the straight section and the top end point of the curved section are connected by welding.

[0027] The distance Hqa from the top end point of the curved section to the sea surface satisfies Hqa≥0.2k.

[0028] The support frame is connected to the tail plate of the FSRU by bolts.

[0029] Without using the method, the free-falling lifeboat has a high gravitational potential energy, and in the process of free-falling to the sea surface, the gravitational potential energy is converted into kinetic energy, so that the free-falling lifeboat has a certain initial speed when entering the water, so that the free-falling lifeboat will enter the sea water a certain distance under the action of the initial speed, which is usually about 2 times the length of the free-falling lifeboat. This release method does not pose a danger when the FSRU is sailing, but when the FSRU is moored to the dock for LNG receiving and gasification operations, the water depth of the dock is usually about 10 meters, and the free-falling lifeboat is usually not less than 20 meters. Using the free-falling release method, the free-falling lifeboat will collide with the seabed, causing casualties.

[0030] Using the free-falling lifeboat guide rail falling method disclosed by the application, the guide rail tool is used in the process of lowering the free-falling lifeboat, so that the lowering direction is gradually changed from the original β to about 3°, so that the initial speed direction when the free-falling lifeboat falls into the water is also changed from the original β to about 3°. Therefore, the lifeboat moves in the horizontal direction under the action of the initial speed when it falls into the water, and does not enter the sea water, avoiding the possibility of the free-falling lifeboat touching the bottom and ensuring the safety of personnel escaping.

[0031] The application solves the problem that the lifeboat cannot be used when the FSRU is moored to the dock, ensuring the safety and timeliness of the personnel escaping from the FSRU. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 This is a side view of the structure of the present invention;

[0033] Figure 2 This is a side view diagram of the straight section guide rail structure;

[0034] Figure 3 This is a side view schematic diagram of the curved section guide rail structure;

[0035] Figure 4 This is a schematic diagram of the FSRU stern free-fall lifeboat and its frame without the guide rail fixture of this invention installed;

[0036] Figure 5 This is a schematic diagram showing the lifeboat descending to the straight section of the guide rail after the guide rail fixture of this invention has been installed;

[0037] Figure 6 This is a schematic diagram showing the lifeboat descending to the curved section of the guide rail after the guide rail fixture of this invention has been installed;

[0038] Wherein: 1-Straight section guide rail, 2-Curved section guide rail, 3-Support frame, A-Hull, B-Freefall lifeboat, C-Lifeboat frame, α-Inclination angle of the straight section guide rail to the horizontal direction, β-Inclination angle of the lifeboat frame to the horizontal direction, Pzt-Top end point of the straight section guide rail, Lgap-Gap length between the top end point Pzt of the straight section guide rail and the lifeboat frame, Pzb-Bottom end point of the straight section guide rail, Hz-Distance between the top end point Pzt and the bottom end point Pzb of the straight section guide rail, H-Distance from the top end point Pzt of the straight section guide rail to the sea surface, Hqa-Distance from the top end point of the curved section guide rail to the sea surface, Pqt-Top end point of the curved section guide rail, Pqb-Bottom end point of the curved section guide rail, k-Scale coefficient, θ-Curvature at any point on the curved section guide rail, Hqb-Distance from the top end point Pqb of the curved section guide rail to the sea surface, Df-Full-load draft of the freefall lifeboat. Detailed Implementation

[0039] The invention will be further described with reference to the accompanying drawings.

[0040] Example 1:

[0041] This invention provides a free-fall guide rail for FSRU lifeboats, applicable to dock landing operations of FSRU free-fall lifeboats.

[0042] A guide rail fixture is used to assist in the lowering process. The guide rail fixture includes a straight section of guide rail, a curved section of guide rail, and a guide rail support structure, such as... Figure 1 As shown.

[0043] The straight section of the guide rail is straight, serving as a continuation of the lifeboat rack track and acting as a transition from the lifeboat rack to the curved section of the guide rail, such as... Figure 2 As shown.

[0044] The curved segment rail top receives the linear segment rail, and the bottom extends to the sea, which plays a role in safely lowering the free-fall lifeboat into the sea. As shown in Figure 3 .

[0045] When the FSRU completes mooring at the wharf and enters the operating state, its free-fall lifeboat is as shown in Figure 4 .

[0046] Taking a certain type of 160-person free-fall lifeboat as an example, the length of the lifeboat is 16.1 meters, the full load draft is 2m, the lifeboat rack angle β = 35°, and it is applied to a certain type of FSRU.

[0047] The 160-person lifeboat belongs to a large lifeboat, so Lgap is selected as 20mm, thereby determining the position of the top end point Pzt of the linear segment rail.

[0048] The maximum freeboard of the FSRU wharf mooring is 10.4m, combined with the position of Pzt, H = 13m is determined.

[0049] The 160-person lifeboat belongs to a large lifeboat, so k is taken as 25, Hqa is taken as 5m, and Hqb is taken as 2m.

[0050] Hz= H-Hqa=8m. α=β=35°, so the length of the linear segment rail is 13.948m.

[0051] From the top end point Pqt of the curved segment rail to the bottom end point Pqb of the curved segment rail, the rail satisfies the following formula:

[0052] x=25(θ-sinθ);

[0053] y=25(1-cosθ);

[0054] Hqb is not less than the full load draft of the lifeboat, that is, Hqb ≥ 2m, and here Hqb = 2m. Pqt coincides with Pzb, and the distance from Pqb to the sea surface is Hqb = 2m.

[0055] When a major accident occurs on the FSRU, the personnel on board need to escape by taking the lifeboat:

[0056] 1. Open the lifeboat release device, and the lifeboat slides downward along its own rack rail at an angle of β.

[0057] 2. Slide to the linear segment rail part, and the lowering direction of the lifeboat does not change (α=β), as shown in Figure 5 .

[0058] 3. When sliding to the curved segment rail, the lowering direction of the lifeboat gradually changes from the initial α to 3°, as shown in Figure 6 .

[0059] Finally, the lifeboat is released into the water at an angle of 3° to the horizontal, and the free fall is completed, ensuring the safe landing of the lifeboat in the limited water depth area of the wharf.

Claims

1. An FSRU lifeboat free fall guide rail characterized by, The ship is provided with a lifeboat rack, the lifeboat rack is arranged obliquely, the lifeboat is fixed on the lifeboat rack, a landing guide rail is arranged obliquely downward along the tail of the lifeboat rack, and the tail of the landing guide rail extends into water; The landing guide rail is composed of a straight section guide rail and a curved section guide rail, the straight section guide rail is connected to the lifeboat rack, a gap Lgap exists between the straight section guide rail and the lifeboat rack, 5mm≤Lgap≤20mm, and rollers are arranged on the surface of the straight section guide rail; the top end point of the curved section guide rail is tangent to the straight section guide rail, and the bottom end point of the curved section guide rail forms an angle of 3° with the horizontal plane; The vertical distance Hz between the top end point Pzt and the bottom end point Pzb of the straight section guide rail satisfies Hz=H-Hqa; H is the distance from the top end point Pzt of the straight section guide rail to the sea surface; Hqa is the distance from the top end point of the curved section guide rail to the sea surface; The lower surface of the landing guide rail is fixed with a truss support frame, the support frame is continuously arranged along the direction of the landing guide rail, and one end of the support frame is fixed to the FSRU stern plate.

2. A free fall guide rail for FSRU lifeboat according to claim 1, characterized in that, From the top end point of the curved section guide rail to the bottom end point of the curved section guide rail, the curved section guide rail is part of the brachistochrone curve, and the following formula is satisfied: ； k is a curvature coefficient, and is valued according to the length of the free-falling lifeboat, 20m≤k≤25m; θ is the curvature of any point on the curved section guide rail.

3. A free fall guide rail for FSRU lifeboat according to claim 1, characterized in that, The distance Hqb from the top end point of the curved section guide rail to the sea surface satisfies Hqb≥Df, and Df is the full load draft of the free-falling lifeboat.

4. The FSRU lifeboat freefall guide rail of claim 1, wherein, The inclination angle α of the straight section guide rail with the horizontal plane is the same as the inclination angle β of the lifeboat rack with the horizontal direction.

5. The FSRU lifeboat freefall guide rail of claim 1, wherein, The vertical distance Hz between the top end point and the bottom end point of the straight section guide rail satisfies Hz=H-Hqa; H is the distance from the top end point of the straight section guide rail to the sea surface, and Hqa is the distance from the top end point of the curved section guide rail to the sea surface.

6. The FSRU lifeboat freefall guide rail of claim 1, wherein, The bottom end point of the straight section guide rail and the top end point of the curved section guide rail are connected by welding.

7. The FSRU lifeboat freefall guide rail of claim 1, wherein, The distance Hqa from the top end point of the curved section guide rail to the sea surface satisfies Hqa≥0.2k.

8. The FSRU lifeboat freefall guide rail of claim 1, wherein, The support frame is connected to the tail plate of the FSRU by bolts.

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