Subdivision and strengthening method of the bottom tank of a medium-sized twin-screw LNG carrier

Abstract

The application relates to a method for segment division and reinforcement of a middle double stern LNG ship engine room bottom basin outfitting, which comprises the following steps: dividing the engine room bottom segment into a basin outfitting area structure; reinforcing the structure of two engine room bottom side half-solid segments; supporting and arranging constraint welding when assembling the front and rear half-solid segments of the two engine room bottom side half-solid segments; and increasing constraint welding before unhooking in the loading stage of the two engine room bottom side total segments. The method for segment division and reinforcement of the middle double stern LNG ship engine room bottom basin outfitting has the effects of high-integrity basin outfitting without increasing excessive ship structure weight, improves the integrity of the middle product of the engine room area, and improves the ship construction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of shipbuilding, in particular to a method for segment division and reinforcement of a bottom pot outfitting of a medium-sized twin-screw LNG ship engine room. BACKGROUND

[0002] In the process of shipbuilding, the conventional single shafting ship pot outfitting scheme is to add a layer of side platform between the engine room double bottom and the upper deck, and the side platform is slightly higher than the perforated steel platform, so as to ensure the complete installation of the perforated steel plate and related equipment. It is found in the process of production and application that this method has the following disadvantages: the added layer of side platform is usually a permanent platform, which increases the structural weight of the ship body, which is not conducive to the control of the empty ship weight; even if a small number of side platforms are designed as temporary reinforcement structures, it will cause a large amount of waste of plate materials, and the work load of the later removal and polishing of the temporary platform is huge, which is not conducive to the rapid loading of the propulsion implementation.

[0003] Large and medium-sized ships continue to use the conventional pot outfitting method, which increases the weight of the permanent side platform, wastes resources, and increases the labor and time cost, even if the partial outfitting integrity is improved.

[0004] The prior art (CN113715986A) discloses a method for installing a pot outfitting unit, comprising: dividing the pot outfitting unit into at most eight modules, and the remaining part is included in the remaining outfitting part; the plurality of modules and the ship body side section are mixedly installed; the remaining outfitting part is installed, the basis for module division is the installation position, weight, volume and connection relationship with other equipment of each equipment in the pot outfitting unit, the remaining outfitting part is the equipment in the pot outfitting unit which is not divided into modules, and the equipment not divided into modules includes abstract equipment, equipment at the module connection, and equipment connected with the ship body side section. The technical scheme of the present application divides the pot outfitting unit into a plurality of modules and a remaining outfitting part, and then flexibly adjusts the installation sequence and / or installation route of the modules, the remaining outfitting part and the ship body side section according to the shape, installation position and other factors of the modules, the remaining outfitting part and the ship body side section, which greatly reduces the installation difficulty and improves the installation efficiency. However, it does not solve the problem that the side platform increases the structural weight of the ship body. SUMMARY

[0005] To solve the technical problems existing in the prior art, the present application provides a method for segment division and reinforcement of a bottom pot outfitting of a medium-sized twin-screw LNG ship engine room, which improves the integrity of the outfitting in the engine room bottom area without increasing the empty ship weight.

[0006] To achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0007] A method for segment division and reinforcement of the bottom pot outfitting of a medium-sized twin stern LNG ship engine room, the method comprising the following steps:

[0008] Step one, dividing the engine room bottom segments, combining the engine room bottom area with the cargo hold transverse bulkhead to form a pot-shaped structure;

[0009] Step two, reinforcing the structure of the left and right engine room bottom side half-solid segments;

[0010] Step three, supporting the left and right engine room bottom side front and rear half-solid segment assemblies;

[0011] Step four, tack-welding the left and right engine room bottom side front and rear half-solid segment assemblies;

[0012] Step five, adding tack-welding to the left and right engine room bottom side segment assemblies before unhooking during the loading stage.

[0013] As a preferred technical solution, in step one, dividing the engine room bottom segments includes the following steps: attaching the lower opening structure of the longitudinal bulkhead of the left engine room bottom half-solid segment to the left engine room bottom segment, with the height of the perforated steel plate platform part being higher; attaching the lower opening structure of the longitudinal bulkhead of the right engine room bottom half-solid segment to the right engine room bottom segment, with the height of the perforated steel plate platform part being higher; and keeping the lower opening structure of the longitudinal bulkhead of the left and right sides of the middle engine room bottom deck segment of the original engine room bottom segment division unchanged.

[0014] As a preferred technical solution, in step two, a diagonal slot steel is added to the position where the left and right engine room bottom side half-solid segments are disconnected along the ship length direction.

[0015] As a preferred technical solution, the disconnected position includes the upper part of the longitudinal bulkhead and the rib plate.

[0016] As a preferred technical solution, in step three, supporting the left and right engine room bottom side front and rear half-solid segment assemblies includes the following steps: normally assembling the left and right engine room bottom side front and rear half-solid segments, placing the lower part of the front and rear half-solid segment assemblies on the assembly foundation pier, placing the divided longitudinal bulkhead on the first stabilizer, and installing support seats in the large area of the outer plate line type and arranging the second stabilizer for support.

[0017] As a preferred technical solution, in step four, when the left engine room bottom side half-solid segment assemblies are assembled front and rear, two tack-welds are arranged on the deck surface of the front and rear butt joints along the ship width direction, and one tack-weld is arranged on the bottom plate of the front and rear butt joints. The right side also has three corresponding tack-welds.

[0018] As a preferred technical scheme, in step five, the constraint welding of the two cabin bottom side sections before the unhooking stage is increased, including the following steps: before the unhooking of the left cabin bottom side section, five constraint welds are arranged along the ship length direction at the unhooking joint of the lower opening rib plate of the section, four constraint welds are arranged along the ship length direction at the unhooking joint of the deck surface of the section near the ship's center, and nine corresponding constraint welds are arranged on the right side.

[0019] Compared with the prior art, the method has the following beneficial effects:

[0020] (1) The method for segment division and strengthening of the bottom cabin of a medium-sized twin stern LNG ship, by attaching the longitudinal bulkhead lower opening structure of the two cabin bottom half-solid sections to the corresponding bottom sections, respectively, and by providing three corresponding solutions of channel steel strengthening, tool support and unhooking constraint welding for the three problems of weak structure strength of the cabin bottom side section or the total section, uneven lower opening structure, and difficulty in placing and easy overturning during the unhooking stage, realizes the effect of high-integrity basin outfitting without increasing the weight of the ship structure.

[0021] (2) The method realizes modular construction of the cabin bottom basin outfitting, can reduce about 50% of the bulk cargo in the cabin bottom area, and greatly improves the integrity of the intermediate products in the cabin area.

[0022] (3) The method can realize rapid forming of the cabin double-bottom area, and the outfitting parts of the cabin double-bottom area can be modularly constructed and hoisted, and almost all bulk pipes and folded pipes can be cancelled, greatly reducing the number of crane uses and improving the construction efficiency of the ship.

[0023] (4) The method can shorten the installation period of the cabin area outfitting parts, and can realize pipe system tightness in advance, and carry out mooring test after the ship is launched, which can effectively reduce the labor intensity of the construction personnel, improve the economic benefit and operation efficiency.

[0024] (5) The method optimizes the segment division of the double-stern cabin bottom structure, and provides the possibility of moving more outfitting work from the total section and the dock stage to the segment stage for subsequent ship construction. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a segment division diagram of the cabin bottom area of a medium-sized twin stern LNG ship of the present application;

[0026] Figure 2 is a total section assembly diagram of the cabin bottom basin outfitting of a medium-sized twin stern LNG ship of the present application;

[0027] Figure 3is the structural schematic diagram of the cabin bottom side half-stereoscopic segment in the application;

[0028] Figure 4 is the structural schematic diagram of the cabin bottom side total segment in the application;

[0029] Figure 5 is the structural schematic diagram of the cabin bottom side half-stereoscopic typical cross-section normal total group support in the application;

[0030] Figure 6 is the structural schematic diagram of the cabin bottom side half-stereoscopic normal total group resting on the pier and the first stabilizer support arrangement in the application;

[0031] Figure 7 is the structural schematic diagram of the cabin bottom side half-stereoscopic total segment before the loose hook restraint welding in the application;

[0032] Figure 8 is the structural schematic diagram of the cabin bottom side half-stereoscopic total segment before the loose hook restraint welding in the application.

[0033] In the figure: 1. Cabin bottom half-stereoscopic segment; 2. Cabin bottom area; 3. Side half-stereoscopic segment; 4. Side total segment; 5. Total group pier; 6. First stabilizer; 7. Support seat. DETAILED DESCRIPTION

[0034] The technical solutions of the application will be further described below in combination with specific embodiments:

[0035] A segment division and reinforcing method for a mid-sized double-stern LNG ship cabin bottom basin outfitting, the method comprising the following steps:

[0036] Step one, as shown in the figure, divide the cabin bottom segment, so that the cabin bottom area 2 and the cargo hold transverse bulkhead combine to form a basin structure; specifically, the lower opening structure of the longitudinal bulkhead of the left side cabin bottom half-stereoscopic segment 1 is higher than the height of the perforated steel plate platform part, which is attached to the left side cabin bottom segment; the lower opening structure of the longitudinal bulkhead of the right side cabin bottom half-stereoscopic segment 1 is higher than the height of the perforated steel plate platform part, which is attached to the right side cabin bottom segment; the lower opening structure of the longitudinal bulkhead of the left and right sides of the original cabin bottom total segment divided middle cabin bottom deck segment is higher than the height of the perforated steel plate platform part, which is attached to the middle cabin bottom segment and remains unchanged, as shown in the figure, the lower opening structure of the four longitudinal bulkheads is attached to the corresponding connected bottom segment respectively, which jointly participates in the total group of the cabin bottom segment, as shown in the figure, the cabin bottom area 2 and the cargo hold transverse bulkhead combine to form a basin structure, and modular construction is carried out on this basis. Figure 1 Figure 2 Figure 3

[0037] ​​​Step 2: Strengthen the structure of the semi-three-dimensional section 3 at the bottom of the engine room on both sides; add diagonally braced channel steel to the upper part of the longitudinal bulkhead and the broken parts such as the ribs of the semi-three-dimensional section 3 at the bottom of the engine room on both sides along the length of the ship, so that the semi-three-dimensional section 3 at the bottom of the engine room on both sides can be reassembled into a continuous integral structure, thereby strengthening the structural strength of the section and achieving the effect of controlling deformation.

[0038] Step 3: Arrange the supports for the aft and forward semi-three-dimensional sections of the bottom of both engine rooms during assembly; such as... Figure 5 and Figure 6 As shown, the support arrangement for assembling the front and rear semi-three-dimensional sections at the bottom of the two engine rooms includes the following steps: Assembling the front and rear semi-three-dimensional sections at the bottom of the two engine rooms in a normal manner; placing the lower, lower part of the front and rear semi-three-dimensional sections at the bottom of the two engine rooms on the assembly pier 5; placing the separated longitudinal bulkheads on the first stabilizing frame 6; installing support seats 7 in the larger areas of the outer plate and arranging a second stabilizing frame for support, thus solving the problem of inconvenient placement and easy overturning due to uneven lower structure.

[0039] Step four involves applying constraint welds to the fore and aft semi-three-dimensional sections at the bottom of the engine room on both sides. When assembling the fore and aft semi-three-dimensional sections 3 at the bottom of the engine room on the port side, two constraint welds are applied along the beam direction on the deck surface of the fore and aft docking joints, and one constraint weld is applied on the bottom outer plating of the fore and aft docking joints. The same three constraint welds are applied to the starboard side to address the issue of easy tipping during the unhooking phase of the section assembly.

[0040] Step 5, as Figure 7 As shown, constraint welding is added to the bottom side section 4 of both engine rooms before the hook is released during the loading stage.

[0041] The steps for adding restraint welding to the bottom side sections 4 of both engine rooms before unhooking during the loading phase include: Figure 8 As shown, before the unhooking of the main section 4 at the bottom of the left engine room, five restraint welds are arranged along the length of the ship at the mounting joint of the lower rib plate of the main section, and four restraint welds are arranged along the length of the ship at the mounting joint of the main section near the midships on the deck surface. The same nine restraint welds are also arranged on the starboard side to solve the problem of easy tipping during the unhooking stage of the main section.

[0042] This embodiment is merely a further explanation of the present invention and is not intended to limit the present invention. Those skilled in the art can make non-inventive modifications to this embodiment as needed after reading this specification, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for segmenting and reinforcing the bottom outfitting of the engine room of a medium-sized twin-stern LNG carrier, characterized in that... The method includes the following steps: Step 1: Divide the engine room bottom section to form a basin-shaped structure by combining the engine room bottom area with the cargo hold transverse bulkheads. The division of the engine room bottom section includes the following steps: attach the lower opening of the longitudinal bulkhead of the semi-three-dimensional engine room bottom section on the port side to the port side engine room bottom section at the height of the portion above the steel plate platform; attach the lower opening of the longitudinal bulkhead of the semi-three-dimensional engine room bottom section on the starboard side to the starboard side engine room bottom section; and attach the lower opening of the longitudinal bulkheads on both sides of the mid-engine room bottom deck section, which was originally divided into the engine room bottom section, to the mid-engine room bottom section, keeping the height of the portion above the steel plate platform unchanged. Step two: Strengthen the structure of the semi-three-dimensional sections at the bottom of both engine rooms; Step 3: Arrange the supports for the aft and stern semi-three-dimensional sections at the bottom of the engine room on both sides. Step 4: Perform constraint welding on the aft and stern semi-three-dimensional sections of the bottom of the engine room on both sides. Step 5: Add constraint welding to the bottom side sections of both engine rooms before unhooking during the loading phase.

2. The method for segmenting and reinforcing the bottom basin outfitting of the engine room of a medium-sized twin-stern LNG carrier according to claim 1, characterized in that, In step two, diagonally braced channel steel is added to the section where the semi-three-dimensional sections on the bottom of the engine room on both sides are broken along the length of the ship.

3. The method for segmenting and reinforcing the bottom basin outfitting of the engine room of a medium-sized twin-stern LNG carrier according to claim 2, characterized in that... The disconnected sections include the upper opening of the longitudinal bulkhead and the ribs.

4. The method for segmenting and reinforcing the bottom basin outfitting of the engine room of a medium-sized twin-stern LNG carrier according to claim 1, characterized in that, In step three, the support arrangement for assembling the front and rear semi-three-dimensional sections at the bottom of the two engine rooms includes the following steps: assembling the front and rear semi-three-dimensional sections at the bottom of the two engine rooms in a normal manner; placing the lower part of the front and rear semi-three-dimensional sections at the bottom of the two engine rooms on the assembly pier; placing the separated longitudinal bulkheads on the first directional frame; and installing support seats and arranging a second directional frame for support in the larger areas of the outer plate.

5. The method for segmenting and reinforcing the bottom basin outfitting of the engine room of a medium-sized twin-stern LNG carrier according to claim 1, characterized in that... In step four, when assembling the semi-three-dimensional section at the bottom of the left engine room, two constraint welds are arranged and welded along the width direction on the deck surface of the fore and aft dock joints, and one constraint weld is arranged and welded on the bottom outer plate of the fore and aft dock joints. The same three constraint welds are also arranged and welded on the starboard side.

6. The method for segmenting and reinforcing the bottom basin outfitting of the engine room of a medium-sized twin-stern LNG carrier according to claim 1, characterized in that, In step five, the addition of constraint welds to the bottom side sections of the engine room on both sides before the hook is released during the loading stage includes the following steps: before the hook is released from the loading of the bottom side section of the engine room on the left side, five constraint welds are arranged and welded along the length of the ship at the loading joint of the lower rib plate of the section, four constraint welds are arranged and welded along the length of the ship at the loading joint of the section on the deck surface near the midships, and nine corresponding constraint welds are welded on the starboard side.

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