A method of ship inspection

Abstract

The present application provides a kind of ship inspection method, which does not need to measure after the whole ballast tank is built completely, divides the ballast tank inspection into each weld and each grid area inspection, advances test time, shortens later period, saves cost. Inspection step is carried out in advance, and the construction of containment system can start immediately after the ballast tank structure is complete, advancing the start time of containment system construction and shortening the total construction period. Compared with dry test, the inspection method does not need to fill the ballast tank on the dock pier, eliminating the risk of hull plate pressure deformation. Compared with pre-completion test, early test can find problems early and solve problems early, without causing the loss of removing the containment system due to leakage found before completion. By setting a reasonable margin of 15% and controlling the structure grid area exemption test range, both test operation and risk control under exemption test are ensured.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, and in particular to an inspection method for testing the tightness and strength of ships. Background Technology

[0002] Liquefied natural gas (LNG), with its green, environmentally friendly, and efficient advantages, has long been the preferred energy source to replace oil, becoming one of the fastest-growing energy industries globally. With my country's rapid economic development and increasingly stringent environmental governance requirements, the application and development of LNG have received growing attention. Since the Methane Pioneer began trial operation in 1959, the global LNG transportation industry has undergone more than 60 years of development. During this process, LNG carrier technology has evolved from small, simple, and basic to large, complex, and specialized. Among these technologies, the cargo containment system is one of the core technologies of LNG carriers, and the rapid construction and rhythmic construction of this system are key factors affecting the construction cycle of LNG carriers.

[0003] However, existing construction methods for LNG carrier cargo containment systems have the following problems:

[0004] 1. A ballast tank strength test needs to be conducted after the main hull of the ship has been fully loaded and launched, such as... Figure 1 As shown, the ballast tank 200 is located on the side and bottom of the liquid cargo tank 100. The ballast tank 200 is filled with water to test its tightness and structural strength. The construction of the containment system will be carried out after the ballast tank is inspected. The construction of the containment system starts late and has a long cycle, which prolongs the ship construction cycle. Moreover, the ballast tank strength test is carried out at the dock after launching, which occupies dock resources and increases costs.

[0005] 2. Some projects employ dry-state testing (i.e., the ship is not floating in water, but placed on dock piers for water filling) to conduct ballast tank tightness and strength tests, such as... Figure 2 As shown, however, because the ballast tank 200 has a large capacity, after water is added on the slipway, it is very heavy, and there is no external water pressure from seawater to counteract the internal water pressure of the ballast tank, which may cause the outer plating of the ship to deform.

[0006] 3. Alternatively, the ballast tank can be inspected during construction, with the containment system installed first and tests conducted before completion. However, if problems arise during the strength or tightness tests, resulting in leakage, especially at the boundary of the containment system, repairs will be extremely difficult, requiring the removal of the containment system and causing significant economic losses.

[0007] Therefore, how to design a new testing method is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of the shortcomings of the prior art described above, the present invention provides a ship inspection method, comprising the following steps:

[0009] S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. A tightness test is conducted on each internal weld of each spliced ​​panel: a sealing cover is covered at the internal weld to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the internal weld. According to the different positions of each spliced ​​panel after splicing to form the ballast tank, the corresponding pressure value is selected. The lower the position of the internal weld of the spliced ​​panel after splicing to form the ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test.

[0010] S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. A strength test is performed on the grid area of ​​the second surface: a pressure test is performed on the grid area of ​​the second surface to simulate real water pressure, and it is observed whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members.

[0011] S3: After testing each splicing panel, assemble and weld the splicing panels to form a ballast tank. Conduct a tightness test on the splicing welds during the assembly process of each splicing panel, which is the same as the tightness test on the internal welds, to ensure that there is no leakage at the splicing welds.

[0012] S4: During the sea trial phase or before the delivery of the ship, the ballast tanks are fully loaded and checked. The ballast tanks are filled with water and tested for leaks at the welds and for deformation in the reinforced grid areas.

[0013] Preferably, the pressure applied for the strength test is achieved by vacuum adsorption, which includes a combination of a vacuum hood and a vacuum pump. The vacuum pump is placed in the grid area of ​​the second surface and a vacuum is drawn, and the deformation of the grid area is observed to see if it meets the requirements.

[0014] Preferably, the pressure for the strength test is applied by gravity pressure. The spliced ​​panels are placed flat on the support frame, and a pressure iron is placed in the grid area of ​​the second surface to observe whether the deformation of the grid area meets the requirements.

[0015] Preferably, the pressure applied for the airtightness test is a hydrostatic test or a pneumatic test; the hydrostatic test is to inject water into the sealed cavity, pressurize it with a pressurizing device, and check whether there is water leakage at the weld; the pneumatic test is to fill the sealed cavity with a gas mixed with a color developer, pressurize it with a pressurizing device, and check whether there is gas leakage, the gas being filled is one or more of helium, ammonia, and nitrogen.

[0016] Preferably, the method for calculating the pressure values ​​applied at each test point during the tightness test and strength test is as follows:

[0017] When the ship has no roll or trim, the vertical distance between the test point and the highest point of the ballast tank is set to H. The test point is either a weld or a grid area. After the ballast tank is filled with water, if there is no seawater outside the test point, the maximum water pressure that the test point can withstand is P = ρ * g * H. During the tightness test or strength test, the pressure applied to the test point is P * (1 + 15%). ρ represents the water density, and the seawater density is selected in the calculation, with a value of 1.025 t / m³. 3 g represents the acceleration due to gravity, with a value of 9.81 m / s². 2 .

[0018] Preferably, after the ballast tank is filled with water, if there is seawater outside the location of the detection point, the maximum water pressure that the detection point can withstand is P = ρ*g*H - ρ*g*L, where L represents the vertical distance between the detection point and the shallowest draft waterline.

[0019] Preferably, within the same splicing panel, if the relative height difference between two grid areas is less than 15% of the total height of the ballast tank, and the type and arrangement of the reinforcing members surrounding the grid area are the same, then only one grid area is subjected to a strength test.

[0020] Preferably, after the splicing panels are assembled to form a ballast tank, a temporary hoist is welded at the boundary of the ballast tank to facilitate lifting and movement. After the temporary hoist is used up, the temporary hoist can be retained or cut off. If the temporary hoist is cut off, the separation point of the ballast tank must be ground, and a tightness test must be performed on the ground area, which is the same as the tightness test operation of the internal weld.

[0021] This invention also provides another method for ship inspection, comprising the following steps:

[0022] S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. A tightness test is conducted on the internal welds of each spliced ​​panel that contact the outer boundary plate. A sealing cover is placed over the internal welds to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the internal welds. Depending on the position of each spliced ​​panel after it is assembled into a ballast tank, an appropriate pressure value is selected. The lower the position of the internal weld of the spliced ​​panel after it is assembled into a ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test.

[0023] S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. A strength test is performed on the grid area of ​​the second surface that contacts the outer boundary plate: a pressure test is performed on the grid area of ​​the second surface to observe whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members.

[0024] S3: After testing each splicing panel, assemble and weld the splicing panels to form a ballast tank. Conduct a tightness test on the splicing welds during the assembly process of each splicing panel, which is the same as the tightness test on the internal welds, to ensure that there is no leakage at the splicing welds.

[0025] S4: During the sea trial phase or before delivery of the ship, a full-load check of the ballast tanks is carried out. The ballast tanks are filled with water, and tests are conducted to check for leaks at the welds and for deformation in the reinforced grid areas. This includes testing the internal welds and grid areas that do not contact the outer boundary plates.

[0026] This invention also provides another method for ship inspection, comprising the following steps:

[0027] S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. Each spliced ​​panel includes multiple internal welds. A leak test is performed on some of the internal welds or not. The leak test is as follows: a sealing cover is placed over the weld to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the weld. The corresponding pressure value is selected according to the different positions of each spliced ​​panel after it is spliced ​​to form the ballast tank. The lower the position of the weld of the spliced ​​panel after it is spliced ​​to form the ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test.

[0028] S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. Strength tests are performed on each grid area of ​​the second surface: pressure tests are performed on the grid areas of the second surface to observe whether the deformation meets the requirements. At the same time, after releasing the pressure, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members.

[0029] S3: After the tests of each splicing panel are completed, the splicing panels are assembled and welded to form a ballast tank. A tightness test is conducted on the splicing welds during the assembly process of each splicing panel, and a tightness test is conducted on the internal welds that were not tested in step S1.

[0030] S4: During the sea trial phase or before the delivery of the ship, the ballast tanks are fully loaded and checked. The ballast tanks are filled with water and tested for leaks at the welds and for deformation in the reinforced grid areas.

[0031] As described above, this invention provides a ship inspection method that eliminates the need for measurement after the entire ballast tank is fully constructed. The ballast tank inspection is broken down into checks of individual welds and grid areas, allowing for earlier testing, shortening the later construction period, and saving costs. The inspection steps are carried out in advance, allowing the containment system construction to begin immediately after the ballast tank structure is complete, thus shortening the overall construction cycle. Compared to dry-state testing, this method eliminates the risk of hull plate deformation by not filling the ballast tank on the dock. Compared to pre-completion testing, early testing allows for the early detection and resolution of problems, preventing losses due to leaks discovered before completion and the need to dismantle the containment system. By setting a reasonable 15% margin and controlling the scope of exempted testing for structural grid areas, testing operations are reduced, construction time is shortened, and construction costs are saved, while also ensuring that the risks under exempted testing are controllable. By distinguishing between contact parts and non-contact parts at the outer boundary, structural components and welds that do not contact the splicing panels with the outer boundary plate can be inspected separately during the construction phase before segmented splicing. This increases the flexibility of the test operation, allows for flexible matching of the construction period during the test, and improves construction efficiency. Attached Figure Description

[0032] Figure 1 The diagram shows a schematic of a ballast tank strength test conducted after a ship has been launched, based on existing technology.

[0033] Figure 2 This is a schematic diagram of a ballast tank strength test on a slipway in the prior art.

[0034] Figure 3 This diagram illustrates the inspection of weld tightness in this invention.

[0035] Figure 4 The diagram shown is a schematic representation of the ballast tank and weld seam in this invention.

[0036] Figure 5 The diagram shown is a schematic of the ballast tank in this invention, which is divided into multiple spliced ​​panels.

[0037] Figure 6 The diagram shown is a structural schematic of the weld and reinforcement in this invention.

[0038] Figure 7 The diagram shows a schematic of a strength test conducted using vacuum in this invention.

[0039] Figure 8 The diagram shows a strength test conducted using a pressure iron in this invention.

[0040] Figures 9 to 13 This diagram illustrates the calculation of water pressure values ​​at the weld under different conditions.

[0041] Figure 14 This shows a strength test when the reinforcements are of the same type.

[0042] Figure 15 The display shows strength tests when the reinforcement is of different types.

[0043] Component designation explanation

[0044] 11 First splicing section

[0045] 12 Second splicing section

[0046] 13 Third splicing section

[0047] 21 Weld

[0048] 22 Reinforcing components

[0049] 23 Grid Area

[0050] 31 Sealing Cover

[0051] 32. Boosting equipment

[0052] 33 Vacuum Shield

[0053] 34 Vacuum Pump

[0054] 35 Support frame

[0055] 36. Press iron

[0056] 100 liquid cargo tanks

[0057] 200 Ballast Tanks

[0058] 221 First Reinforcing Component

[0059] 222 Second Reinforcing Component Detailed Implementation

[0060] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0061] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0062] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for the device in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or there may be one or more layers in between. The phrase “between” as used herein includes both endpoint values.

[0063] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0064] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0065] This invention provides a ship inspection method, including a weld tightness test and a reinforcement strength test;

[0066] The tightness test is as follows: Figure 3 , Figure 4As shown, a sealing cover 31 is placed over weld 21 to form a sealed cavity. During testing, the pressure within the sealed cavity is used to simulate real water pressure to observe whether there is leakage at weld 21. Depending on the location of weld 21 within the ballast tank 200, a corresponding pressure value is selected. The lower the location of weld 21 within the ballast tank 200, the greater the real water pressure that weld 21 needs to withstand after the ballast tank is filled with water, and the greater the pressure value applied during the experiment. The ballast tank is formed by splicing and welding multiple interlocking panels. Figure 5 As shown, as an example, the ballast tank 200 includes a first splicing plate 11, a second splicing plate 12, and a third splicing plate 13. The number of splicing plates can be divided according to the actual situation, and is not limited to 3.

[0067] The strength test is as follows: Figures 6 to 8 As shown, horizontally and vertically arranged reinforcing members 22 are reinforced on the first surface of the splicing plate. The horizontally arranged reinforcing members and the vertically arranged reinforcing members intersect perpendicularly and form multiple grid areas 23. The splicing plate has a second surface opposite to the first surface. A pressure test is performed on the grid area 23 of the second surface to observe whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement strength of the reinforcing members. Here, after the pressure is released, the change in the flatness of the grid area can be measured to determine whether it returns to its original shape.

[0068] Specifically, the pressure applied in the strength test, such as Figure 7 As shown, a combination of vacuum chamber 33 and vacuum pump 34 can be selected. The vacuum pump is placed on the grid area of ​​the second surface and a vacuum is drawn. The deformation of the grid area is then observed to see if it meets the requirements. Figure 8 As shown, alternatively, the splicing panels can be laid flat on the support frame 35, and a pressure iron 36 can be placed in the grid area of ​​the second surface to observe whether the deformation of the grid area meets the requirements.

[0069] For the pressure application in the leak test, a hydrostatic test can be used. Water is injected into the sealed cavity, and the pressure is increased by the pressurization device 32 to check for water leakage at the weld. Alternatively, a gas pressurization test can be used. A gas mixed with a color developer is filled into the sealed cavity, and the pressure is increased by the pressurization device 32 to check for gas leakage. The pressurized gas can be helium, ammonia, or nitrogen with added color developer, etc.

[0070] Furthermore, each individual splicing panel has an internal weld, and multiple splicing panels are spliced ​​together to form a splicing weld. The tightness test of the internal weld is conducted before the splicing panels are assembled or after the splicing panels form the ballast tank; the tightness test of the splicing weld is conducted after the splicing panels form the ballast tank. Preferably, conducting the tightness test of the internal weld before the splicing panels are assembled allows for simultaneous testing of multiple splicing panels and advances the testing time, changing the original wharf construction test to a segmented stage test, reducing wharf occupation time and shortening the construction period. As an optional solution, the tightness test of some internal welds can also be conducted before splicing, and the remaining tightness tests can be conducted after the splicing forms the ballast tank.

[0071] Specifically, the calculation method for the pressure values ​​applied at each test point during the tightness test and strength test is as follows:

[0072] Let H be the vertical distance between the test point and the highest point of the ballast tank when the ship has no roll or trim. The test point is either a weld or a grid area. After the ballast tank is filled with water, if there is no seawater outside the test point, the maximum water pressure the test point will bear is P = ρ * g * H; if there is seawater outside the test point, the maximum water pressure the test point will bear is P = ρ * g * H - ρ * g * L. During the tightness test or strength test, the pressure applied to the test point is P * (1 + 15%). ρ represents the water density, which is selected as seawater density in the calculation, with a value of 1.025 t / m³. g represents the acceleration due to gravity, with a value of 9.81 m / s². L represents the vertical distance between the test point and the shallowest draft waterline.

[0073] Taking the calculation of the pressure value of the weld as an example, such as Figure 9 , Figure 10 As shown, the vertical distance from the weld to the highest point of the ballast tank when there is no tilt is H. According to the calculation formula, the maximum water pressure it can withstand is P = ρ * g * H. Since H2 is greater than H1, the maximum water pressure that H2 needs to withstand is greater than that at H1.

[0074] like Figure 11 , Figure 12 As shown, the vertical distance between the weld and the highest point of the ballast tank when there is no roll is H3. When there is a roll, the vertical distance between the weld and the highest point of the ballast tank becomes H4. H4 is greater than H3. Therefore, considering the roll and trim of the ship during navigation, the ultimate pressure that the weld should withstand during the tightness test should be 115% of that when there is no roll, which is P*(1+15%).

[0075] like Figure 13As shown, when there is seawater outside the weld location, the maximum water pressure the weld can withstand without heeling is P = ρ*g*H - ρ*g*L. This means that the pressure of the external seawater partially offsets the water pressure inside the ballast tank, reducing the pressure requirement at this weld. The offset portion should be calculated based on the shallowest draft waterline, that is, minimizing L and maximizing P. Here, the shallowest draft waterline refers to the lowest plane of the external seawater relative to the ship when it is in seawater.

[0076] Furthermore, strength tests can be conducted either before the splicing of the panels or after the splicing of the panels to form the ballast tank.

[0077] Within the same splicing panel, if the relative height difference between two grid areas is less than 15% of the total height of the ballast tank, and the type and arrangement of the reinforcing members surrounding the grid area are the same, then only one grid area will be tested for strength.

[0078] Specifically, such as Figure 14 As shown, when the type of reinforcing member is the same, and all use the first reinforcing member 221, then for all grid areas with a relative height difference less than 15% of the total height of the ballast tank, only one grid area needs to be tested for strength, thus reducing the number of tests. However, when the types of reinforcing members surrounding the grid areas are different, such as... Figure 15 As shown, strength tests are still required for each grid area. Here, under specific circumstances, some grid areas are exempt from strength testing. Due to strict limitations on height differences, the exemption test is only conducted within a certain height range. Combined with the aforementioned 15% strength margin reserved for the grid areas, the risk of exemption from testing remains manageable.

[0079] Furthermore, after the spliced ​​panels are assembled to form the ballast tank, temporary lifting jacks (not shown in the figure) are welded at the boundary of the ballast tank to facilitate lifting and movement. After the temporary lifting jacks are used, the option is to either retain them or cut them off. If the temporary lifting jacks are cut off, the separation point of the ballast tank must be ground, and a tightness test must be performed on the ground area, following the same procedure as the tightness test for the internal welds. If the lifting jacks are retained without cutting them, the damage to the tightness of the ballast tank boundary can be reduced.

[0080] Furthermore, during the sea trials or before delivery, a full-load check of the ballast tanks should be conducted. The ballast tanks should be filled with water, and tests should be performed to check for leaks at the welds and deformation in the reinforced mesh areas. During the check test, there should be no other oil or water at the boundaries of the ballast tanks that could cause back pressure, and all welds at the boundaries should be easily accessible for inspection.

[0081] Example 1

[0082] This embodiment provides a ship inspection method that arranges the internal weld tightness test and the reinforcement strength test to be carried out before the splicing of the panels, including the following steps:

[0083] S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. A tightness test is conducted on each internal weld of each spliced ​​panel: a sealing cover is covered at the internal weld to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the internal weld. According to the different positions of each spliced ​​panel after splicing to form the ballast tank, the corresponding pressure value is selected. The lower the position of the internal weld of the spliced ​​panel after splicing to form the ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test.

[0084] S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. Strength tests are performed on each grid area of ​​the second surface: pressure tests are performed on the grid areas of the second surface to simulate real water pressure, and it is observed whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members.

[0085] S3: After testing each splicing panel, assemble and weld the splicing panels to form a ballast chamber. Conduct a tightness test on the splicing welds during the assembly process of each splicing panel, which is the same as the tightness test on the internal welds, to ensure that there is no leakage at the splicing welds.

[0086] S4: During the sea trial phase or before the delivery of the ship, the ballast tanks are fully loaded and checked. The ballast tanks are filled with water and tested for leaks at the welds and for deformation in the reinforced grid areas.

[0087] Example 2

[0088] This embodiment provides a ship inspection method that arranges the testing of internal welds and reinforcements that do not contact the outer boundary plate during full-load verification, including the following steps:

[0089] S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. A tightness test is conducted on the internal welds of each spliced ​​panel that contact the outer boundary plate. A sealing cover is placed over the internal welds to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the internal welds. Depending on the position of each spliced ​​panel after it is assembled into a ballast tank, an appropriate pressure value is selected. The lower the position of the internal weld of the spliced ​​panel after it is assembled into a ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test.

[0090] S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. A strength test is performed on the grid area of ​​the second surface that contacts the outer boundary plate: a pressure test is performed on the grid area of ​​the second surface to simulate real water pressure, and it is observed whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members.

[0091] S3: After testing each splicing panel, assemble and weld the splicing panels to form a ballast chamber. Conduct a tightness test on the splicing welds during the assembly process of each splicing panel, which is the same as the tightness test on the internal welds, to ensure that there is no leakage at the splicing welds.

[0092] S4: During the sea trial phase or before delivery of the ship, a full-load check of the ballast tanks is carried out. The ballast tanks are filled with water, and tests are conducted to check for leaks at the welds and for deformation in the reinforced grid areas. This includes testing the internal welds and grid areas that do not contact the outer boundary plates.

[0093] Example 3

[0094] This embodiment provides a ship inspection method that arranges the testing of some or all internal welds and reinforcements after the splicing and welding assembly forms the ballast tank, including the following steps:

[0095] S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. Each spliced ​​panel includes multiple internal welds. A leak test is performed on some of the internal welds or not. The leak test is as follows: a sealing cover is placed over the weld to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the weld. The corresponding pressure value is selected according to the different positions of each spliced ​​panel after it is spliced ​​to form the ballast tank. The lower the position of the weld of the spliced ​​panel after it is spliced ​​to form the ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test.

[0096] S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. Strength tests are performed on each grid area of ​​the second surface: pressure tests are performed on the grid areas of the second surface to simulate real water pressure, and it is observed whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members.

[0097] S3: After the tests of each splicing panel are completed, the splicing panels are assembled and welded to form a ballast tank. A tightness test is conducted on the splicing welds during the assembly process of each splicing panel, and a tightness test is conducted on the internal welds that were not tested in step S1.

[0098] S4: During the sea trial phase or before the delivery of the ship, the ballast tanks are fully loaded and checked. The ballast tanks are filled with water and tested for leaks at the welds and for deformation in the reinforced grid areas.

[0099] It should be noted that the three embodiments described above differ only in the order of the tests on the weld and reinforcement. Other test conditions and parameters are the same. For example, the specific implementation methods for the tightness test and strength test, the calculation of the pressure value applied at each test point, the conditions for the grid area to be exempt from the strength test, and the handling of the temporary hoist are all carried out with reference to the above test methods.

[0100] In summary, this invention provides a ship inspection method that eliminates the need for measurement after the entire ballast tank is fully constructed. The ballast tank inspection is broken down into checks of individual welds and grid areas, allowing for earlier testing, shortening the later construction period, and saving costs. The pre-construction phased inspection steps allow the containment system construction to commence immediately after the ballast tank structure is complete, shortening the overall construction cycle. Compared to dry-state testing, this method eliminates the risk of hull plate deformation by not filling the ballast tank on the dock. Compared to pre-completion testing, early testing allows for the early detection and resolution of problems, preventing losses due to leaks discovered before completion and the need to dismantle the containment system. By setting a reasonable 15% margin and controlling the exemption range for structural grid areas, testing operations are reduced, construction time is shortened, and construction costs are saved, while also ensuring that the risks under exempted testing are controllable. By distinguishing between contact parts and non-contact parts at the outer boundary, structural components and welds that do not contact the splicing panels with the outer boundary plate can be inspected separately during the construction phase before segmented splicing. This increases the flexibility of the test operation, allows for flexible matching of the construction period during the test, and improves construction efficiency.

[0101] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for ship inspection, characterized in that, Includes the following steps: S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. A tightness test is conducted on each internal weld of each spliced ​​panel: a sealing cover is covered at the internal weld to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the internal weld. According to the different positions of each spliced ​​panel after splicing to form the ballast tank, the corresponding pressure value is selected. The lower the position of the internal weld of the spliced ​​panel after splicing to form the ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test. S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. A strength test is performed on the grid area of ​​the second surface: a pressure test is performed on the grid area of ​​the second surface to simulate real water pressure, and it is observed whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members. S3: After testing each splicing panel, assemble and weld the splicing panels to form a ballast tank. Conduct a tightness test on the splicing welds during the assembly process of each splicing panel, which is the same as the tightness test on the internal welds, to ensure that there is no leakage at the splicing welds. S4: During the sea trial phase or before the delivery of the ship, the ballast tanks are fully loaded and checked. The ballast tanks are filled with water and tested for leaks at the welds and for deformation in the reinforced grid areas. The calculation method for the pressure applied at each test point during the tightness and strength tests is as follows: Assume the vertical distance H between the test point and the highest point of the ballast tank when the ship has no roll or trim. The test point is either a weld or a grid area. After filling the ballast tank with water, if there is no seawater outside the test point, the maximum water pressure borne by the test point is P = ρ * g * H. During the tightness or strength test, the pressure applied at the test point is P * (1 + 15%). ρ represents the water density; in the calculation, the seawater density is selected, with a value of 1.025 t / m³. 3 g represents the acceleration due to gravity, with a value of 9.81 m / s². 2 After the ballast tank is filled with water, if there is seawater outside the location of the detection point, the maximum water pressure that the detection point will bear is P=ρ*g*H-ρ*g*L, where L represents the vertical distance between the detection point and the shallowest draft waterline.

2. The ship inspection method according to claim 1, characterized in that, The pressure applied for the strength test is achieved through vacuum adsorption, which involves a combination of a vacuum hood and a vacuum pump. The vacuum pump is placed on the grid area of ​​the second surface and a vacuum is drawn. The deformation of the grid area is then observed to see if it meets the requirements.

3. The ship inspection method according to claim 1, characterized in that, The pressure applied for the strength test is achieved by applying gravity pressure. The spliced ​​panels are placed flat on the support frame, and a pressure iron is placed in the grid area of ​​the second surface. The deformation of the grid area is observed to see if it meets the requirements.

4. The ship inspection method according to claim 1, characterized in that, For the pressure application in the airtightness test, a hydrostatic test or a pneumatic test is used. The hydrostatic test involves filling the sealed cavity with water, pressurizing it with a pressurizing device, and checking whether there is water leakage at the weld. The pneumatic test involves filling the sealed cavity with a gas mixed with a color developer, pressurizing it with a pressurizing device, and checking whether there is gas leakage. The gas filled in is one or more of helium, ammonia, and nitrogen.

5. The ship inspection method according to claim 1, characterized in that: Within the same splicing panel, if the relative height difference between two grid areas is less than 15% of the total height of the ballast tank, and the type and arrangement of the reinforcing members surrounding the grid areas are the same, then only one grid area will be tested for strength.

6. The ship inspection method according to claim 1, characterized in that: After the splicing panels are assembled to form the ballast tank, temporary hoists are welded at the boundary of the ballast tank to facilitate lifting and movement. After the temporary hoists are used, the temporary hoists can be retained or cut off. If the temporary hoists are cut off, the separation point of the ballast tank must be ground, and a tightness test must be performed on the ground area, which is the same as the tightness test operation for the internal welds.

7. A method for ship inspection, characterized in that, Includes the following steps: S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. A tightness test is conducted on the internal welds of each spliced ​​panel that contact the outer boundary plate. A sealing cover is placed over the internal welds to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the internal welds. Depending on the position of each spliced ​​panel after it is assembled into a ballast tank, an appropriate pressure value is selected. The lower the position of the internal weld of the spliced ​​panel after it is assembled into a ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test. S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. A strength test is performed on the grid area of ​​the second surface that contacts the outer boundary plate: a pressure test is performed on the grid area of ​​the second surface to observe whether the deformation meets the requirements. At the same time, after the pressure is released, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members. S3: After testing each splicing panel, assemble and weld the splicing panels to form a ballast tank. Conduct a tightness test on the splicing welds during the assembly process of each splicing panel, which is the same as the tightness test on the internal welds, to ensure that there is no leakage at the splicing welds. S4: During the sea trial phase or before the delivery of the ship, the ballast tanks are fully loaded and checked. The ballast tanks are filled with water and tested for leaks at the welds and for deformation in the reinforced grid areas. This includes testing the internal welds and grid areas that do not contact the outer boundary plates. The calculation method for the pressure applied at each test point during the tightness and strength tests is as follows: Assume the vertical distance H between the test point and the highest point of the ballast tank when the ship has no roll or trim. The test point is either a weld or a grid area. After filling the ballast tank with water, if there is no seawater outside the test point, the maximum water pressure borne by the test point is P = ρ * g * H. During the tightness or strength test, the pressure applied at the test point is P * (1 + 15%). ρ represents the water density; in the calculation, the seawater density is selected, with a value of 1.025 t / m³. 3 g represents the acceleration due to gravity, with a value of 9.81 m / s². 2 After the ballast tank is filled with water, if there is seawater outside the location of the detection point, the maximum water pressure that the detection point will bear is P=ρ*g*H-ρ*g*L, where L represents the vertical distance between the detection point and the shallowest draft waterline.

8. A method for ship inspection, characterized in that, Includes the following steps: S1: The steel plates used to form the ballast tank are divided into multiple spliced ​​panels. Each spliced ​​panel includes multiple internal welds. A leak test is performed on some of the internal welds or not. The leak test is as follows: a sealing cover is placed over the weld to form a sealed cavity. During the test, the pressure value inside the sealed cavity is used to simulate the real water pressure value, and it is observed whether there is any leakage at the weld. The corresponding pressure value is selected according to the different positions of each spliced ​​panel after it is spliced ​​to form the ballast tank. The lower the position of the weld of the spliced ​​panel after it is spliced ​​to form the ballast tank, the greater the real water pressure it needs to withstand, and the greater the pressure value during the test. S2: The first surface of the splicing plate is reinforced with horizontally and vertically arranged reinforcing members. The horizontally arranged reinforcing members intersect perpendicularly with the vertically arranged reinforcing members and form multiple grid areas. The splicing plate has a second surface opposite to the first surface. Strength tests are performed on each grid area of ​​the second surface: pressure tests are performed on the grid areas of the second surface to observe whether the deformation meets the requirements. At the same time, after releasing the pressure, the grid area can return to its original shape to ensure that the deformation is elastic deformation and to ensure the reinforcement effect of the reinforcing members. S3: After the tests of each splicing panel are completed, the splicing panels are assembled and welded to form a ballast tank. A tightness test is conducted on the splicing welds during the assembly process of each splicing panel, and a tightness test is conducted on the internal welds that were not tested in step S1. S4: During the sea trial phase or before the delivery of the ship, the ballast tanks are fully loaded and checked. The ballast tanks are filled with water and tested for leaks at the welds and for deformation in the reinforced grid areas. The calculation method for the pressure applied at each test point during the tightness and strength tests is as follows: Assume the vertical distance H between the test point and the highest point of the ballast tank when the ship has no roll or trim. The test point is either a weld or a grid area. After filling the ballast tank with water, if there is no seawater outside the test point, the maximum water pressure borne by the test point is P = ρ * g * H. During the tightness or strength test, the pressure applied at the test point is P * (1 + 15%). ρ represents the water density; in the calculation, the seawater density is selected, with a value of 1.025 t / m³. 3 g represents the acceleration due to gravity, with a value of 9.81 m / s². 2 After the ballast tank is filled with water, if there is seawater outside the location of the detection point, the maximum water pressure that the detection point will bear is P=ρ*g*H-ρ*g*L, where L represents the vertical distance between the detection point and the shallowest draft waterline.

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