JP5197433B2 - Ship - Google Patents

Description

  The present invention relates to a ship for transporting solid cargoes that generate combustible gases such as natural gas hydrate (NGH) pellets.

  Recently, natural gas hydrate has attracted attention, and it has been studied to transport natural gas in the form of gas hydrate pellets in bulk. As shown in FIG. 9, in a general bulk carrier 1 </ b> X, when viewed in cross section, the bulk carrier 10 includes a bottom inner plate 11, an outer plate of a hopper side tank (a wall plate on the bulk cargo 10 side) 12. The ship side inner plate 13 and the outer plate of the top side tank (wall plate on the bulk cargo hold 10 side) 14 are enclosed (for example, refer to Patent Document 1).

  As joints for joining the steel plates forming this bulk cargo hold, T joints and cross joints by fillet welding and butt joints by butt welding are frequently used. When this fillet welded joint is used, various weld defects are likely to occur in the welded portion of the fillet weld, and the inspection of the welded portion is a nondestructive inspection by an ultrasonic flaw detection test. For this reason, it is difficult to completely ensure the reliability of the welded joint part, for example, a radiation test with high reliability cannot be performed compared to butt welding.

  On the other hand, when steel plates are joined together by a butt joint by butt welding, it is necessary to provide a groove prior to welding, but it is possible to perform sufficient penetration and ensure airtightness, As for the pass / fail inspection, a nondestructive inspection can be performed by a radiation test which is more reliable than the ultrasonic flaw detection test. Therefore, if a butt joint by butt welding is used, it is easy to find a welding defect that causes gas leakage, and a more sound welded joint structure can be realized, and maintenance after service is facilitated.

  In the bulk cargo ship of the prior art, since airtightness is not required, not all the welded parts of the inner wall are made into butt joints by full penetration butt welding. As shown in FIG. The connection of the steel plates that make up the inner wall of the warehouse 10 is often joined by a fully-melting butt joint W1, but the inner wall includes a joint with a longitudinal girder and upper deck in the double hull. Between the steel plates of the partition members 17, 18, and 19 that partition between the steel plates forming the slab and the double bottom 5, the hopper side tank 6, the ship side space portion 7, and the top side tank 8, that is, the knuckle portion (corner Part) N is often joined by a welded joint W2 by fillet welding because it is difficult to control the accuracy of bending.

  However, when a solid cargo that generates flammable gas, such as natural gas hydrate pellets, is transported on a bulk carrier, flammable gas is generated, so the flammable gas is adjacent to the welded joint on the inner wall of the cargo hold. The possibility of leaking into the compartment to be mixed with air (oxygen) to form an explosion atmosphere, and conversely, the possibility of air entering the cargo hold and forming an explosion atmosphere in the cargo hold is eliminated. Desired.

  In particular, in a bulk carrier 1X having a double hull structure in which a ship side space 7 is provided between a ship side outer plate 3 and a ship side inner plate 11 as shown in FIGS. The ballast tank and pipe space provided in the ship side space 7 and the side hopper tank 6 are damaged by the collision of other ships when the flammable gas leaks from the bulk cargo hold 10. In such a case, a large amount of air may flow into the portions 6 and 7 adjacent to the bulk cargo hold 10 and a rapid explosion atmosphere may be formed, which may cause a major accident.

  Therefore, when transporting solid materials that generate flammable gas, it is important to ensure airtightness at the welded joints, especially for shipboard inner plates that constitute double hulls, etc. It is required to have a welded joint structure.

JP-A-2005-219677

  The present invention has been made in view of the above-described situation, and the object thereof is a ship equipped with a bulk cargo hold for storing a solid material that generates flammable gas in a bulk load state, in an inner wall of the bulk cargo hold. Combustion by significantly reducing the possibility of flammable gas leakage from the welded joint into the bulk cargo compartment from the bulk cargo hold and into the bulk cargo hold from the adjacent compartment. An object of the present invention is to provide a ship capable of preventing an explosion due to mixing of sex gas and air.

In order to achieve the above object, the ship of the present invention is a ship having a bulk cargo hold for storing a solid material generating a flammable gas in a bulked state, and is a longitudinal direction of the ship forming the inner wall of the bulk cargo hold. In the connection between the steel plates facing the bulk cargo area, the vertical bulkhead provided in the bulk cargo area provided with the bulk cargo hold is not completely welded without using a welded joint by fillet welding. They are joined using only butt joints , and are formed by longitudinal plate members joined using weld joints by fillet welding in connection with steel plates outside the bulk cargo hold .

  In other words, between the front end and the rear end of the bulk cargo area composed of a plurality of cargo holds adjacent to each other across the horizontal bulkhead, the steel plate of the ship side inner plate and the steel plate of the bottom inner plate are connected to these steel plates. The steel plate forming the inner wall excluding the transverse bulkhead of the bulk cargo hold is vertically passed, and the welded joint of the longitudinal plate member forming the inner wall that is passed through is constituted only by a butt joint by full penetration butt welding. That is, the steel plate forming the inner side of the cargo hold, excluding the horizontal bulkhead, is formed of a longitudinal plate member formed of only a butt joint and continuous with a single plate-like body.

  According to this configuration, since the inner bottom plate of the bulk cargo area, the outer plate of the hopper side portion, the inner side plate of the ship side, and the outer plate of the top side tank are connected only by a completely-melting butt joint, The possibility that the flammable gas generated in the warehouse leaks from the welded joint portion of the inner wall to the ship bottom side, the ship side, or the like can be significantly reduced. Therefore, there is almost no possibility of flammable gas leaking into the ship side space of the ship side double wall structure, so even when another ship collides with the ship side outer plate, the ship side double wall structure Combustion gas and air (oxygen) are not mixed in the ship side space, and explosion can be prevented.

  In the ship described above, the longitudinal plate member and the steel plate forming the hatch combing are also formed by joining with a butt joint by butt welding with complete penetration.

According to this configuration, it is possible to significantly reduce the possibility of flammable gas generated in the bulk cargo hold from leaking to the outside from the welded portion between the longitudinal plate member and the hatch combing or the longitudinal plate member and the upper deck. In the case where the upper plate steel plate and the longitudinal plate member continuously connected in a single plate shape are joined by a welded joint by fillet welding, in the welded joint portion of the longitudinal plate member and the hatch combing It is possible to avoid the possibility of passage of combustible gas due to welding defects.

In the above vessel, the connection of the steel plate forming the transverse bulkhead located at the foremost end of the bulk cargo area, the connection of the steel plate forming the horizontal bulkhead located at the rearmost end of the bulk cargo area, and both 3. The connection between the steel plate forming the partition wall and the longitudinal plate member is formed by joining the steel plates facing the bulk cargo hold with only a completely butt joint. The listed ship.

  According to this configuration, the longitudinal plate member continuously connected in a single piece in the bulk cargo area, the transverse bulkhead steel plate at the foremost end, and the transverse bulkhead steel plate at the rearmost end are connected in a single piece by butt welding. Due to the above structure, the possibility that the combustible gas generated in the bulk cargo hold is leaked to the outside due to welding defects can be remarkably reduced even in the longitudinal direction of the bulk cargo area.

In the above-mentioned ship, in the longitudinal plate member, at least a part of the portion where the other steel material is connected to the inner wall of the bulk cargo area, the portion where the other steel material is connected to the butt joint of the steel material forming the inner wall When the steel material forming the inner wall and the other steel material are joined by a welded joint by fillet welding, and the direction of the steel material forming the inner wall is changed, the direction is changed. The steel material forming the inner wall is bent, the butt joint is provided at the tip of the bent portion, and the joining of the other steel materials is performed on the base side from the portion where the bent portion starts.

  According to this configuration, it is possible to easily join a portion where the direction of the steel sheet changes without using a fillet welded weld joint, using only a completely-melted butt joint. In addition, since the joining of other steel materials is performed at the base side, that is, at the portion that is not the bent portion, the welded portion can be avoided from being added to the bent portion, and the quality of the steel material can be easily secured. become able to.

In the above-mentioned ship, in the one-plate inner wall plate, a part of a portion where the steel material forming the inner wall of the bulk cargo area and other steel materials are connected , and the three steel materials are formed in a joined shape. Using a three-pronged steel material, the steel material forming the inner wall and the other steel material are joined to the three-pronged steel material by a fully-penetrating butt joint.

  According to this configuration, a T-joint by fillet welding can be used, and even a portion where the direction of the steel plate changes can be joined using only a butt joint by butt welding with complete penetration.

  In the above-described ship, a fully closed cover having an airtight structure in which a cargo handling device can move is provided on the upper deck of the bulk cargo area. By this fully closed cover, it is possible to prevent the combustible gas generated during the cargo handling operation from being released into the atmosphere.

  According to the ship of the present invention, since the welded joints of steel materials forming the longitudinal inner wall in the bulk cargo area of the bulk cargo hold are all completely butt joints, it is possible to reduce defects caused by the welded parts. Compared with the ultrasonic detection test used for the welded joint by fillet welding, the quality of welding can be determined by a more reliable radiation test, so that excellent airtightness can be ensured.

It is the sectional side view which showed the structure of the ship in embodiment which concerns on this invention. It is the top view which showed the structure of the ship in embodiment which concerns on this invention. It is the cross-sectional view which showed the structure of the ship in embodiment which concerns on this invention. It is a perspective view including the cross section which showed the structure of the bulk cargo hold in embodiment which concerns on this invention. It is the typical cross-sectional view which showed the welding structure of the bulk cargo hold in embodiment which concerns on this invention. It is the typical cross-sectional view which showed the other example of the welding structure of the bulk cargo hold in embodiment which concerns on this invention. It is the typical cross-sectional view which showed the other example of the welding structure of the bulk cargo hold in embodiment which concerns on this invention. It is the typical cross-sectional view which showed the example of the welding structure of the bulk cargo hold of a prior art. It is the cross-sectional view which showed the structure of the bulk carrier of a prior art.

  Hereinafter, a ship according to the present invention will be described with reference to the drawings. Note that the drawings show an outline of the hull structure and hatch structure, and do not show a detailed structure, and details of reinforcing members such as beams and stiffeners are omitted.

  As shown in FIGS. 1 to 4, a ship 1 according to an embodiment of the present invention is configured to include a ship bottom skin 2, a ship side skin 3, an upper deck 4, and the like, and generates flammable gas. For example, a bulk cargo hold 10 for storing natural gas hydrate (NGH) pellets in bulk. In addition, LWL in the drawings of FIGS. 1 and 3 indicates a full waterline.

  When viewed in a cross section of the hull, the vessel 1 is surrounded on the outside by a vessel bottom skin 2, a vessel side skin 3 and an upper deck 4. The inner wall of the bulk cargo hold 10 includes a vessel bottom inner plate 11, a hopper side. It consists of a tank 6 outer plate (cargo hold 10 side plate) 12, a ship side inner plate 13, and a top side tank 8 outer plate (cargo hold 10 side plate) 14. The upper deck 4 or hatch combing ( (Kuraguchi rim material) 20 is connected.

  The ship bottom inner plate 11 constitutes a double bottom 5 together with the ship bottom outer plate 2, and the ship side inner plate 11 constitutes a ship side space 7 together with the ship side outer plate 3. The hopper side tank 6 is provided below both sides of the bulk cargo hold 10, and the top side tank 8 is provided above both sides of the bulk cargo hold 10. These hopper side tank 6, ship side space 7 and top side tank 8 are used as part of a ballast tank or pipe space.

  Further, in the longitudinal direction of the hull, the front bulkhead 15a is partitioned from the bow section 30, the bulkheads 10 are partitioned by the horizontal bulkhead 15b, and the engine section is partitioned by the rear horizontal bulkhead 15c. 40 is partitioned. A cofferdam (gap) 16a is formed between the front lateral bulkhead 15a and the bow section 30, and a cofadam 16b is disposed between the lateral bulkheads 15b between the bulk cargoes 10 and the rear lateral bulkhead 15c and the engine. A cofferdam 16 c is provided between the compartments 40. A bulk cargo area L in which bulk cargo is loaded is formed between the front horizontal bulkhead 15a and the rear horizontal bulkhead 15c. In other words, the horizontal bulkhead 15a becomes the horizontal bulkhead at the foremost end of the bulk cargo area L, and the horizontal bulkhead 15c becomes the horizontal bulkhead at the end of the bulk cargo area L.

  Further, a hold 10a is provided in the upper part of the bulk cargo hold 10, a hatch combing 20 is provided around the hold 10a, and a hatch cover 21 is placed thereon. In the case of a lifting type hatch cover, the hatch cover 21 is lifted up to a moving rail installed above and moved onto the front or rear hatch cover to open the hatch 10a. The hatch cover 21 is configured to prevent the intrusion of seawater, rainwater, etc. during the voyage so as to prevent the intrusion of seawater, rainwater, etc., and the cargo generates flammable gas. The space is configured to be an airtight structure.

  Further, an unloader (loading device) moving space 50 having an airtight structure surrounded by a side wall 51, a ceiling 52, a front end wall 53, and a rear end wall 54 is provided so as to cover the entire bulk cargo hold 10. The unloader moving space 50 prevents the flammable gas generated during the cargo handling operation for bulking cargo from being released into the atmosphere.

  And in the ship 1 of embodiment of this invention, the vertical bulkheads 11, 12, 13, and 14 (hatching part by a diagonal line) provided in the front-back direction of the ship which forms the inner wall of the bulk cargo hold 10 are made into bulk cargo. As shown in FIGS. 5 to 7, in the joining of steel plates over the entire bulk cargo area L provided with the warehouse 10, as shown in FIGS. 5 to 7, a welded joint (T joint or cross joint by fillet welding) W2 is used. Without using it, it is formed of longitudinal plate members that are continuously connected in a single sheet by using only the completely-melted butt joint W1.

  Longitudinal bulkheads 11, 12, 13, 14 provided in the longitudinal direction of the ship are constituted by a ship bottom inner plate 11, a hopper side tank 6 outer plate 12, a ship side inner plate 13, and a top side tank 8 outer plate 14. Is done.

  As shown in FIG. 5, the longitudinal plate member is provided with a bent portion (curve) C in the steel material facing the inside of the bulk cargo hold 10 in a portion where the cross section is Y-shaped or T-shaped. And it joins by the butt joint W1 in the part which avoided this bending part C. Thereby, it forms with the longitudinal plate member connected continuously in one sheet | seat using only the butt joint W1 by the butt welding of complete penetration. Moreover, in order to maintain the quality of the steel joint, by providing the butt joint W1 at a portion deviated from the bent portion C, it is possible to avoid both bending and welding of the steel.

  In the case of FIG. 5, the longitudinal partition walls 11, 12, 13, 14 formed of longitudinal plate members are the ship bottom inner plate 11, the outer plate 12 of the hopper side tank 6, the ship side inner plate 13, the top side tank. Although the outer plate 14 of the top side tank 8 is connected to the upper deck 4 from the lower side, the outer plate 14 of the top side tank 8 is connected to the upper deck 4 continuously. Crossed and joined by a welded joint W2 by fillet welding on both sides of the outer plate 14.

  Due to the continuous structure of the longitudinal plate members, the combustible gas generated in the bulk cargo hold 10 is welded to the double bottom 5, the hopper side tank 6, the ship side space 7, and the top side tank 8 around the bulk cargo hold 10. The possibility of flowing out from the joint portion can be remarkably reduced. On the other hand, the possibility that air enters the bulk cargo hold 10 from the welded joint portion from the surrounding partition portions 5, 6, 7, and 8 where air enters and exits can be significantly reduced.

  In the case of the longitudinal plate member shown in FIG. 6, the longitudinal partition walls 11, 12, 13, 14 are the ship bottom inner plate 11, the outer plate 12 of the hopper side tank 6, the ship side inner plate 13, and the outer plate of the top side tank 8. In addition to 14, the hatch combing 20 is continuously connected in a single sheet by using only the completely-melting butt joint W1. In other words, the longitudinal plate member and the steel plate forming the hatch combing 20 are also formed by joining with the completely-melting butt joint W1.

  In this configuration, the upper deck 4 is joined by a welded joint W2 by fillet welding on both sides of the upper deck 4 on the side opposite to the bulk cargo hold 10. According to this configuration, it is possible to prevent flammable gas from leaking from the welded joint portions of the longitudinal partition walls 11, 12, 13, 14, the upper deck 4, and the hatch combing 20.

  In the longitudinal plate member shown in FIG. 7, the partition walls 11, 12, 13, 14, and 20 are three-pronged members 60 having a Y-shaped or T-shaped cross section, and the ship bottom inner plate 11 and the outer plate 12 of the hopper side tank 6. In addition to the ship side inner plate 13 and the outer plate 14 of the top side tank 8, the hatch combing 20 is continuously connected in a single sheet using only the completely butt joint W <b> 1. In this case, the steel plate of the partition member 17 between the double bottom 5 and the hopper side tank 6, the steel plate of the partition member 18 between the hopper side tank 6 and the ship side space portion 7, and the partition between the ship side space portion 7 and the top side tank 8. The steel plate of the member 19 is also joined to the three-pronged member 60 by a fully-melting butt joint W1.

  In FIG. 7, the outer plate 14, the hatch combing 20, and the upper deck 4 of the top side tank 8 are also connected to each other by only the butt joint W <b> 1 that is completely melted by the three-pronged member 60. However, although the airtightness is slightly inferior, the portion connected to the upper deck 4 can be connected by a welded joint W2 by fillet welding as shown in FIG.

  The three-pronged member 60 is a steel material formed in a shape in which three plate-like members are attached, and since the three plate members are already connected, the steel plates are joined by a butt joint W1 by butt welding. Can be easily done. Therefore, according to this structure, since the bending process for forming the bending part C becomes unnecessary, work becomes easy.

  According to the above configuration, the inner bottom plate 11 of the bulk cargo area L, the outer plate 12 of the hopper side tank 6, the inner side plate 13 of the ship side, and the outer plate 14 of the top side tank 8 are joined by the fully-melting butt joint W1. Therefore, there is a possibility that flammable gas generated in the bulk cargo hold 10 leaks from the welded joint portion of the longitudinal partition walls 11, 12, 13, 14 forming the inner wall to the outside of the bulk cargo hold 10. Can be significantly reduced. Therefore, even when another ship collides with the ship side skin 3, the mixture of combustible gas and air (oxygen) in the ship side space 7 in the double wall structure on the ship side is avoided to prevent explosion. can do.

  On the other hand, the possibility that air enters the bulk cargo hold 10 from the double bottom 5, the hopper side tank 6, the ship side space 7, and the top side tank 8 where air may enter and exit is extremely small. Thus, the explosion can be prevented by avoiding that the air is mixed with the combustible gas.

  In this case, the concentration of the combustible gas is increased by supplying an inert gas (inert gas) to the cofferdam 16a in front of the horizontal partition wall 15a located at the foremost end of the bulk cargo area L. To prevent. Thereby, it corresponds to the leakage of the combustible gas from the welded portion of the horizontal partition wall 15a and the welded joint portion between the vertical partition walls 11, 12, 13, 14 and the horizontal partition wall 15a. Further, the same action is taken by the cofferdam 16c located behind the horizontal bulkhead 15c located at the rearmost end of the bulk cargo area L. Further, in the horizontal bulkhead 15b between the bulk cargo holds 10 in the bulk cargo area L, the same countermeasure is taken by the cofferdam 16b.

  Furthermore, the above-described longitudinal bulkheads 11, 12, 13, 14 and the steel plate of the horizontal bulkhead 15a located at the foremost end of the bulk cargo area L, the steel plate of the horizontal bulkhead 15c located at the rearmost end of the bulk cargo area L, Are formed by joining only by a fully-melting butt joint W1. With this configuration, the longitudinal partition walls 11, 12, 13, 14 and the horizontal partition wall 15a and the horizontal partition wall 15c are formed as a single continuous plate-like member with a butt joint W1 that is completely melted. The entire L can be wrapped. Therefore, the possibility that flammable gas leaks from the welded joint part and the possibility of air entering from the welded part not only on the ship bottom side or ship side but also on the front and rear of the bulk cargo area L may be significantly reduced. it can.

  The ship of the present invention is a longitudinal plate member formed by joining between the inside and the outside of a bulk cargo hold only with a completely melted butt joint when transporting solid matter generating flammable gas in a bulk state. The possibility of flammable gas leaking from the inside of the bulk cargo through the welded joint and the possibility of air entering the inside from the outside of the bulk cargo through the welded joint is significantly reduced. It is possible to prevent explosion hazard due to mixing of combustible gas and air. Therefore, it can utilize as a ship which conveys the solid substance which generate | occur | produces combustible gas, such as NGH hydrate, in a bulk state.

DESCRIPTION OF SYMBOLS 1 Ship 4 Upper deck 5 Double bottom 7 Ship side space 6 Hopper side tank 8 Top side tank 10 Bulk cargo hold 11 Ship bottom inner plate (longitudinal bulkhead)
12 Outer plate of hopper side tank (longitudinal bulkhead)
13 Ship inner plate (longitudinal bulkhead)
14 Outer plate of top side tank (longitudinal bulkhead)
15a Horizontal bulkhead at the foremost end 15c Horizontal bulkhead at the rearmost end 20 Hatch combing (Kuraguchi rim material)
50 Unloader moving space 60 Three-pronged member C Bent part L Bulk cargo area W1 Complete penetration butt joint W2 Fillet welded joint

Claims (6)

In a ship equipped with a bulk cargo hold that stores solid matter that generates flammable gas in a bulked state, a vertical bulkhead provided in the front-rear direction of the ship forming the inner wall of the bulk cargo hold is provided with the bulk cargo hold. Throughout the entire bulk cargo area, the steel plates facing the bulk cargo hold are joined using only a fully-welded butt joint instead of a welded joint by fillet welding . A ship characterized in that it is formed of a longitudinal plate member joined using a welded joint by fillet welding in connection with a steel plate on the outside .   The marine vessel according to claim 1, wherein the longitudinal plate member and the steel plate forming the hatch combing are also formed by joining with a completely-melting butt joint. Connection of steel plates forming a horizontal bulkhead located at the foremost end of the bulk cargo area, connection of steel plates forming a horizontal bulkhead located at the rearmost end of the bulk cargo area, and steel plates forming both bulkheads The ship according to claim 1 or 2, wherein , in the connection between the longitudinal plate members and the longitudinal steel plate members, the steel plates facing the bulk cargo hold are joined by only a completely butt joint. In the longitudinal plate member, at least a part of the portion where the other steel material is connected to the inner wall of the bulk cargo area, the position where the butt joint of the steel material forming the inner wall is separated from the portion where the other steel material is connected The steel material forming the inner wall and the other steel material are joined by a welded joint by fillet welding, and when the direction of the steel material forming the inner wall changes, the inner wall is formed in that direction. The steel material to be bent is bent, the butt joint is provided at the tip of the bent portion, and the joining of the other steel material is performed on the base side from the portion where the bent portion starts. The listed ship. In the longitudinal plate member, a part of a portion where the steel material forming the inner wall of the bulk cargo area and the other steel material are connected , and a three-pronged steel material formed by joining three steel materials is used. The marine vessel according to claim 1, 2, or 3, wherein the steel material having an inner wall and another steel material are joined to the three-pronged steel material by a completely-melting butt joint.   6. The ship according to claim 1, 2, 3, 4, or 5, wherein a fully closed cover having an airtight structure is provided on the upper deck of the bulk cargo area.

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