Construction method for newly adding and transforming self-flowing device of ship

Abstract

The invention relates to a construction method for newly adding and transforming a self-flowing device to a ship, and belongs to the technical field of ships. The method comprises the steps that the installation position of the self-flowing device on a ship body is determined according to the function requirement of the self-flowing device and the structural strength of the ship body; defining a to-be-cut area on the ship body by taking the mounting position as a center; separating the to-be-cut area from the ship body to form ship body sections; in a workshop meeting the construction environment, manufacturing and mounting of the self-flowing device are completed on the outer surface of the ship body section; and the ship body sections integrated with the self-flowing device are subjected to butt welding again, and it is ensured that the ship body structure recovers to the original design load standard. By means of a modular construction system of cutting, segmented transformation and reinstallation, the problem that traditional slipway construction cannot meet the high construction condition requirement and the high-precision forming requirement of the self-flowing device is successfully solved, the construction environment, the construction space and the posture of manufacturing of the self-flowing device can be remarkably improved, the construction difficulty is reduced, and the construction efficiency is improved. The profile precision of the self-flowing device is improved, and the boarding applicability of the self-flowing device is improved.

Description

Technical Field

[0001] The present application relates to the field of ship technology, and in particular to a construction method for newly adding and modifying a gravity flow device on a ship. Background Art

[0002] Currently, ships generally use traditional pump-flow cooling water systems, which rely on cooling water pumps to draw seawater from the ship's side to cool the condenser or heat exchanger in the power system. The cooling water pumps are constantly running, requiring high power consumption and generating significant vibration and noise. Furthermore, if a cooling water pump fails and shuts down, the system cannot continue to operate, compromising the safety and reliability of the ship.

[0003] To overcome these issues, ships and submarines are increasingly adopting gravity cooling technology. These devices, installed externally on the hull, leverage the pressure head of the water flow during navigation to allow seawater to overcome the resistance of the system's piping and flow through the heat exchanger. This allows the cooling water pump to be shut down within a certain speed range, enabling gravity-fed operation. This eliminates the system's primary noise source and effectively reduces the cooling water pump's actual operating power under other normal operating conditions, significantly weakening vibration excitation and reducing system radiated noise. Furthermore, even if a cooling water pump fails and shuts down, a certain level of water supply is still guaranteed, improving the reliability and viability of the ship's power plant.

[0004] Compared with the traditional pump-flow cooling system, this gravity cooling system has a new gravity device. The gravity device is generally arranged at the bottom of the hull and extends out of the hull. It has a large size, a three-dimensional complex curved surface and high precision requirements. If the ship is directly modified on the slipway to add a gravity device, its construction environment, construction space and posture (a large number of piers are set at the bottom of the slipway, and the operation needs to be done on the back) and construction technology are difficult to guarantee. Therefore, it is necessary to provide a construction method for adding and modifying the gravity device of the ship to overcome the problem of applying the gravity device on board. Summary of the Invention

[0005] The embodiment of the present application provides a construction method for newly adding and modifying a gravity flow device on a ship, so as to solve the problem of difficulty in onboard application caused by adding a gravity flow device of a gravity cooling system to an existing ship.

[0006] The present invention provides a method for constructing a newly added gravity flow device for a ship, comprising: S1. Determine the installation position of the gravity flow device on the hull based on its functional requirements and the strength distribution of the hull structure; S2. With the installation location as the center, based on the outline dimensions of the gravity flow device and the welding allowance, delineate the area to be cut on the hull, with the boundary of the area to be cut extending to the adjacent supporting members of the hull to ensure the structural integrity of the hull segment after cutting; S3, cutting along the boundary of the area to be cut, so as to separate the area to be cut from the hull, and forming an independent hull segment including the installation position; S4, drilling holes on the outer surface of the hull segment, welding flow channels at the holes, and welding metal frames between the flow channels and the hull segment, thereby completing the fabrication and installation of the gravity flow device; S5. Reposition the hull sections with integrated gravity flow devices to the cut notches in the hull, perform butt welding, and inspect the quality and strength of the welds to ensure that the hull structure is restored to the original design load standard.

[0007] In some embodiments, the metal frame includes ring ribs, transverse ribs, and longitudinal brackets, which are welded to each other to form a three-dimensional grid-shaped supporting metal frame, and the metal frame is welded and fixed to the outer wall of the flow channel; The inner cavity enclosed by the metal frame is filled with a light pressure-resistant material to cover the flow channel, and an outer shell plate is formed on the outer surface of the material. The outer shell plate is connected to the hull segment and the metal frame through embedded parts.

[0008] In some embodiments, the area to be cut is a rectangular segment, the size of which encloses the entire gravity flow device, and a reinforcement structure is pre-welded on the inner surface of the segment before cutting to prevent deformation during cutting; After the welding is restored, the reinforcement structure on the inner surface of the segment is cut and removed, and the removed area is repaired by welding.

[0009] In some embodiments, the cutting is performed using a plasma cutting or laser cutting process, and the edges of the cuts are beveled during or after the cutting process to meet subsequent welding requirements.

[0010] In some embodiments, the hull is cut into sections and then transported to a gravity flow device processing workshop, where it is fixed on a clamping fixture with the gravity flow device installation surface facing upward to optimize the construction posture.

[0011] In some embodiments, after the gravity flow device is manufactured, its outer surface is machined or polished in a workshop to ensure that the accuracy of the outer profile meets the design tolerance requirements.

[0012] In some embodiments, the butt welding is performed using a multi-layer, multi-pass welding process, and the heat input is monitored during welding to avoid thermal damage to the composite shell plate and the filler material; The weld inspection includes X-ray non-destructive testing and tightness testing to ensure that there are no pores, cracks or leaks in the weld area.

[0013] In some embodiments, the gravity flow device is manufactured and constructed in a workshop to meet the construction conditions of metal frame welding, weld non-destructive testing conditions, inner cavity lightweight pressure-resistant material construction conditions, and composite material outer shell plate construction conditions.

[0014] In some embodiments, the shell panel is made of fiberglass composite material, and its curing temperature curve includes the following steps: first, starting at 40°C, uniformly heating to 80°C within 2 hours; then maintaining a constant temperature at 80°C for 4 hours; and finally naturally cooling to below 40°C to complete demolding.

[0015] In some embodiments, the lightweight pressure-resistant material is a closed-cell polyurethane foam or epoxy glass microbead composite material with a density of 80 to 500 kg / m 3 , the ambient temperature during filling is controlled at 20 to 30℃.

[0016] The beneficial effects of the technical solution provided by this application include: The embodiment of the present application provides a construction method for newly adding and modifying a gravity flow device on a ship. Through the modular construction system of "cutting-segmented modification-reinstallation", it successfully solves the problem that traditional slipway construction cannot meet the high construction conditions and high-precision molding requirements of gravity flow devices. It can significantly improve the construction environment, construction space and posture of gravity flow device production, reduce construction difficulty, improve the accuracy of the outer contour lines of the gravity flow device, and improve the applicability of the gravity flow device on board. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A flowchart of a method according to an embodiment of the present application; Figure 2 This is a schematic structural diagram of a hull segment according to an embodiment of the present application; Figure 3 This is a structural schematic diagram of the hull segment from another perspective of an embodiment of the present application; Figure 4 This is a schematic structural diagram of a gravity flow device according to an embodiment of the present application; Figure 5 This is a schematic diagram of the connection between the outer shell and the hull of an embodiment of the present application.

[0019] In the accompanying drawings, the components represented by the reference numerals are as follows: 1. Hull; 11. Ribs; 12. Longitudinal girders; 2. Hull sections; 3. Self-flowing devices; 31. Flow channels; 32. Ring ribs; 33. Longitudinal brackets; 34. Skeleton laths; 35. Lightweight pressure-resistant materials; 36. Shell plates; 37. Transverse ribs; 4. Embedded parts; 5. Clay putty; 6. Reinforced structure. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0021] The embodiment of the present application provides a construction method for newly adding and modifying a gravity flow device on a ship, so as to solve the problem of difficulty in onboard application caused by adding a gravity flow device of a gravity cooling system to an existing ship.

[0022] See also Figures 1 to 5 As shown, the embodiment of the present application provides a construction method for adding and modifying a gravity flow device on a ship, comprising: S1. Determine the installation position of the gravity flow device 3 on the hull 1 according to the functional requirements of the gravity flow device 3 and the structural strength distribution of the hull 1; S2. With the installation location as the center, based on the outline dimensions of the gravity flow device 3 and the welding allowance, delineate the area to be cut on the hull 1. The boundary of the area to be cut extends to the adjacent supporting members of the hull 1 to ensure the structural integrity of the hull section 2 after cutting; S3, cutting along the boundary of the area to be cut, so as to separate the area to be cut from the hull 1, and forming an independent hull segment 2 including the installation position; S4. Drill holes in the outer surface of the hull segment 2, weld the flow channel 31 at the hole, and weld a metal frame between the flow channel 31 and the hull segment 2, completing the fabrication and installation of the gravity flow device. S5. Reposition the hull section 2 with the integrated gravity flow device 3 to the cut notch of the hull 1, perform butt welding, and inspect the quality and strength of the weld to ensure that the structure of the hull 1 is restored to the original design load standard.

[0023] The construction method for newly adding and modifying the gravity flow device of a ship in the embodiment of the present application successfully solves the problem that traditional slipway construction cannot meet the high-precision molding requirements of the gravity flow device 3 through a modular construction system of "cutting-segmented modification-reinstallation". It can significantly improve the construction environment, construction space and posture of the gravity flow device 3, reduce the construction difficulty, improve the accuracy of the outer contour line of the gravity flow device 3, and improve the applicability of the gravity flow device 3 on board.

[0024] For example, S1, based on the functional requirements of the gravity flow device 3 and the structural strength distribution of the hull 1, the optimal installation position of the gravity flow device 3 on the hull 1 can be determined; S2. Centering on the optimal installation position, and taking into account the outline dimensions and welding allowance of the gravity flow device 3, define the area to be cut on the hull 1. The boundary of the area to be cut extends to the adjacent supporting members of the hull 1 to ensure the structural integrity of the hull section 2 after cutting. Among them, the area to be cut exceeds the outer contour of the gravity device 3 by at least 50 mm. Before cutting, reinforcing ribs are welded on the edge of the area to be cut to avoid large deformation of the cutting edge. The ribs 11 and longitudinal girders 12 are welded and fixed to the inner wall of the supporting structure hull 1.

[0025] S3, cutting along the boundary of the area to be cut, so as to separate the area to be cut from the hull 1, and forming an independent hull segment 2 including the installation position; Among them, the deformation of segmented cutting can be controlled within 2mm, and the subsequent reinstallation and alignment time can be shortened by 60%.

[0026] S4. Drill holes on the outer surface of the hull segment 2, weld the flow channel 31 at the hole, and weld a metal frame between the flow channel 31 and the hull segment 2, completing the fabrication and installation of the gravity flow device 3; Among them, the hull section 2 is transported to a special workshop, and the gravity device 3 body is further manufactured in the workshop. The gravity device 3 is completely processed and manufactured on the rectangular segment, including the flow channel 31, filling with lightweight pressure-resistant material 35, and composite material shell plate molding. After the gravity device 3 is manufactured, the outer surface can be further polished or machined in the workshop to ensure the design accuracy of the outer line.

[0027] S5. Reposition the hull section 2 with the integrated gravity flow device 3 to the cut notch of the hull 1, perform butt welding, and inspect the quality and strength of the welds to ensure that the structure of the hull 1 is restored to the original design load standard; Specifically, after the gravity device 3 is manufactured, it is transported back to the slipway together with the rectangular segment for welding. The four sides of the rectangular segment are welded to the surrounding hull 1, and the inner structure of the rectangular segment is welded to the side support structure. After the hull 1 is restored, it is verified that the structure of the hull 1 has been restored to the original design load standard to avoid affecting its use. When the gravity device 3 and the hull segment 2 return to the hull 1 for welding, the outer dimensions of the hull segment 2 are larger than the gravity device 3, which can ensure that when welding with the hull 1, the welding heat will not have a thermal impact on the composite material of the outer shell plate 36 and the inner cavity filling material.

[0028] Verification on board has shown that composite hull panels can achieve three times the precision of composite material construction in a workshop environment compared to slipway construction. Furthermore, the use of a segmented reassembly welding process achieves a structural strength recovery coefficient of 0.98, shortening the construction cycle by 40%. For large hull 1 retrofit projects, this approach can save approximately 1,200 hours of work per vessel. Suitable for hulls requiring underwater noise control, it can reduce radiated noise from gravity cooling systems by 18dB.

[0029] In some alternative embodiments: See Figures 1 to 5 As shown, the embodiment of the present application provides a construction method for adding and modifying a gravity flow device on a ship. The metal skeleton of the construction method for adding and modifying a gravity flow device on a ship includes an annular rib 32, a transverse rib 37 and a longitudinal bracket 33. The annular rib 32, the transverse rib 37 and the longitudinal bracket 33 are welded to each other to form a three-dimensional grid-shaped supporting metal skeleton, and the metal skeleton is welded and fixed to the outer wall of the flow channel 31. The inner cavity enclosed by the metal frame is filled with a lightweight pressure-resistant material 35 to cover the flow channel 31, and an outer shell plate 36 is formed on the outer surface of the material. The outer shell plate 36 is connected to the hull segment 2 and the metal frame through embedded parts 4.

[0030] After the inner cavity enclosed by the metal skeleton of the embodiment of the present application is filled with lightweight pressure-resistant material 35, the outer surface of the lightweight pressure-resistant material 35 is machined to the designed curved surface to prepare for the subsequent casting of the outer shell plate 36 directly on the outer surface of the material; the outer shell plate 36 is made of fiberglass composite material. Before casting the outer shell plate 36, embedded bolts are welded on the hull section 2 and the metal skeleton in advance, so that a stable connection can be formed after the outer shell plate 36 is cast.

[0031] Specifically, the metal skeleton can make the vibration acceleration of the flow channel 31 from 5.2m / s 2 Down to 3.1m / s 2 (a 40% reduction), effectively avoiding fatigue cracking of composite materials; the design of embedded part 4 reduces the risk of cracking at the joints between FRP and metal structures; after filling with lightweight materials, the weight of the structural unit is 55% lighter than that of a full steel structure, while meeting impact resistance requirements.

[0032] Exemplarily, the ends of the ring ribs 32 are welded and fixed with skeleton strips 34 for supporting the outer shell 36, and the joints between the skeleton strips 34 and the hull section 2 are filled with mastic putty 5, which can improve the sealing and vibration effects; at the same time, the outer surface of the outer shell 36 and the joints between the hull section 2 are also coated with mastic putty 5, which can make the outer surface of the outer shell 36 and the outer surface of the hull section 2 smoothly transition after adding mastic putty 5, reduce water resistance, and also improve the sealing and vibration effects.

[0033] It should be noted that the solution for applying the gravity device 3 on board a ship provided by the present application is intended to address a series of problems arising from the current application of the gravity device 3 on board a ship of a gravity cooling system. First, the outer shell 36 of the gravity device 3 is generally made of composite materials (glass fiber reinforced plastics) and is laid and cast in a dedicated workshop. The ambient temperature, humidity, air cleanliness, and construction space and posture are subject to strict requirements. If the composite outer shell is directly manufactured on the slipway, the construction environment, construction space and posture (a large number of piers are provided at the bottom of the slipway, and the operation needs to be done in an upright position) and the construction process are difficult to guarantee. Second, the space between the flow channel 31 inside the gravity device 3 and the outer shell plate 36 is generally filled with lightweight pressure-resistant material 35. If filled on the slipway, the adhesive will flow directly downward, and it is impossible to effectively achieve complete filling and bonding reliability; third, the gravity device 3 is generally arranged at the bottom of the hull 1 and has a large external size. A large number of piers are generally arranged at the bottom of the hull 1, and the construction space is limited. It is not convenient to implement it on the slipway site, and the accuracy of the outer line of the gravity device 3 cannot be guaranteed.

[0034] In some alternative embodiments: See Figures 1 to 5 As shown, the embodiment of the present application provides a construction method for a newly added and modified gravity flow device on a ship. The area to be cut in the construction method for a newly added and modified gravity flow device on a ship is a rectangular segment, the size of which envelops the entire gravity flow device 3, and a reinforcement structure 6 is pre-welded on the inner surface of the segment before cutting to prevent deformation during cutting; After welding restoration, the reinforcement structure 6 on the inner surface of the segment is cut and removed, and the removed area is repaired by welding.

[0035] The size of the rectangular segment in the embodiment of the present application envelops the entire gravity device 3, and the edge of the rectangular segment is at least 50 mm away from the edge of the gravity device 3. The rigidity of the segment can be guaranteed after cutting, ensuring that the deformation during transportation is less than 1.8 mm; the reinforcement structure 6 can be a reinforcement rib, which is welded between the inner support structure of the segment, or welded at the edge of the rectangular segment, and welded and fixed to the rib 11 and the longitudinal girder 12 to reduce the cutting thermal deformation of the edge of the rectangular segment, reducing the cutting thermal deformation to 72%, which can reduce the alignment adjustment time when the segment is reinstalled and facilitate welding recovery.

[0036] In some alternative embodiments: See Figures 1 to 5 As shown, an embodiment of the present application provides a construction method for a newly added and modified gravity flow device of a ship. The cutting of the construction method for a newly added and modified gravity flow device of a ship adopts a plasma cutting or laser cutting process, and the edge of the cut is beveled during or after the cutting process to meet subsequent welding requirements.

[0037] The cutting in the embodiment of the present application adopts plasma cutting or laser cutting technology, which can ensure high precision requirements. The incision can be as narrow as 3mm, which can reduce material loss; the groove processing can be performed during the cutting process or after the cutting is completed, and the groove can be set to 20° to 30° to ensure the uniformity of welding penetration and the fatigue life of the weld meets the standard.

[0038] In some alternative embodiments: See Figures 1 to 5 As shown, an embodiment of the present application provides a construction method for a newly added and modified gravity flow device of a ship. The hull segment 2 of the construction method for a newly added and modified gravity flow device of a ship is cut and transported to a gravity flow device 3 processing workshop, and fixed on a clamping tool so that the installation surface of the gravity flow device 3 faces upward to optimize the construction posture.

[0039] After cutting, the hull segment 2 of the embodiment of the present application is transported to a special gravity device 3 processing workshop, fixed on a clamping tool so that the installation surface of the gravity device 3 faces upward to optimize the construction posture, thereby ensuring the positioning and installation accuracy of the gravity device 3 and improving the work efficiency of the composite material shell laying.

[0040] In some alternative embodiments: See Figures 1 to 5 As shown, an embodiment of the present application provides a construction method for a newly added and modified gravity flow device for a ship. After the gravity flow device 3 of the construction method for a newly added and modified gravity flow device for a ship is manufactured, its outer surface is machined or polished in a workshop to ensure that the accuracy of the outer profile meets the design tolerance requirements.

[0041] After the gravity flow device 3 of the embodiment of the present application is manufactured, its outer surface is machined or polished to ensure the fluid performance and structural reliability of the gravity flow device 3. For example, through fine machining by a five-axis CNC machine tool, surface undulations ≥0.1 mm can be eliminated, and the deviation between the outer shell curved surface and the design line can be controlled within ±0.5 mm, which can reduce the flow resistance by 12% to 15%.

[0042] In some alternative embodiments: See Figures 1 to 5 As shown, an embodiment of the present application provides a construction method for a newly added and modified gravity flow device for a ship. The butt welding of the newly added and modified gravity flow device for a ship adopts a multi-layer and multi-pass welding process, and the heat input is monitored during welding to avoid thermal damage to the composite shell plate and the filling material; Weld inspection includes X-ray non-destructive testing and tightness testing to ensure that there are no pores, cracks or leaks in the welding area.

[0043] The multi-layer, multi-pass welding process of the present application utilizes layered and segmented welding to strictly control heat input, ensuring weld quality while avoiding thermal damage to the composite material and filler materials. For example, low heat input (≤15kJ / cm2) welding parameters are employed to limit the heat-affected zone depth to less than 2mm, preventing decomposition or deformation of the composite hull panels (fiberglass reinforced plastics) due to high temperatures (>200°C). Interlayer temperature control (≤120°C) and a symmetrical welding sequence reduce welding deformation, resulting in a uniform stress distribution in the restored hull structure and a reduction of residual stress by more than 30%. The width of each weld is limited to no more than 1.5 times the diameter of the welding gun nozzle, ensuring consistent penetration and avoiding defects such as lack of fusion or slag inclusions.

[0044] X-ray nondestructive testing and tightness testing can ensure the structural integrity and long-term sealing of the weld area. For example, X-ray testing can detect defects such as pores, cracks, and lack of fusion ≥ 0.1 mm with a detection sensitivity of 2% (compared to 5% of traditional ultrasonic testing), ensuring that there are no hidden dangers inside the weld; tightness testing (helium mass spectrometry leak detection) can detect ≤ 1×10 -6The micro leakage of Pa·m³ / s is 100 times more sensitive than traditional water pressure test, avoiding penetration corrosion during long-term operation.

[0045] In some alternative embodiments: See Figures 1 to 5 As shown, an embodiment of the present application provides a construction method for a newly added and modified gravity flow device of a ship. The outer shell plate 36 of the construction method for a newly added and modified gravity flow device of a ship adopts a fiberglass composite material, and its curing temperature curve includes the following steps: first, starting at 40°C, uniformly heating to 80°C within 2 hours; then maintaining a constant temperature at 80°C for 4 hours; finally, naturally cooling to below 40°C to complete demoulding.

[0046] The housing plate 36 of the embodiment of the present application is made of a glass fiber reinforced plastic composite material. It uses a step-by-step temperature curing process to achieve a resin cross-linking degree of over 95%, and a tensile strength of 350 MPa, which is 25% higher than that of conventional curing processes. During the 80°C holding stage, the interlaminar shear strength is maintained at a stable 45 MPa, avoiding the risk of delamination during use. Natural cooling to below 40°C and demoulding can reduce residual stress by 40%, ensuring the long-term dimensional stability of the housing and the metal runner 31. The initial heating stage at 40°C maintains optimal resin viscosity and wettability, enabling fiber volume content of up to 65%. A precise 4-hour hold eliminates temperature gradients across the thickness (infrared thermal imaging shows a temperature difference of less than 3°C), preventing surface overcure and internal undercure. Demolding by natural cooling to below 40°C minimizes mold release deformation to within 0.1 mm / m. This curing method ensures crack-free product performance in -30°C low-temperature impact tests and salt spray resistance exceeding 5,000 hours, meeting the 120-year service life requirement for ship hulls. Surface roughness Ra ≤ 1.6 μm, reducing fluid friction by 12%.

[0047] In some alternative embodiments: See Figures 1 to 5 As shown, the embodiment of the present application provides a construction method for a newly added and modified gravity flow device of a ship. The lightweight pressure-resistant material 35 of the construction method for a newly added and modified gravity flow device of a ship is a closed-cell polyurethane foam or epoxy glass microbead composite material with a density of 80 to 500 kg / m 3 , the ambient temperature during filling is controlled at 20 to 30℃.

[0048] The lightweight pressure-resistant material 35 of the embodiment of the present application is a closed-cell polyurethane foam or epoxy glass microbead composite material, which has high specific strength and can suppress vibration noise. The density is 80 to 500 kg / m 3The closed-cell structure makes its compressive strength reach 0.8 to 1.2 MPa, and the volume shrinkage rate is less than 2% under the pressure of 200m water depth. It can provide stable support for the flow channel 31 and avoid structural deformation caused by fluid impact during navigation. The closed-cell foam structure can also absorb medium and high frequency vibration energy and cooperate with the metal skeleton to reduce the overall vibration acceleration of the gravity flow device 3.

[0049] Filling at a constant temperature of 20 to 30°C ensures that the foaming rate matches the curing time (the expansion rate is stable at 95% to 105%), avoiding low temperatures that cause loose filling (porosity less than 0.5%) or high temperatures that cause premature curing of the adhesive (bonding strength greater than or equal to 2.5MPa).

[0050] It can meet the filling requirements of complex cavities and completely fill the special-shaped space within the metal skeleton (flow distance is greater than 1.5m). After the fiberglass shell is integrally cast on its surface, the interface shear strength can reach 1.8MPa, which can achieve a reliable three-phase combination of metal-composite material-foam.

[0051] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0052] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0053] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A construction method for newly adding and modifying a gravity flow device on a ship, characterized in that: include: Determine the installation position of the gravity flow device on the hull based on its functional requirements and the strength distribution of the hull structure; Taking the installation position as the center, combining the outline size of the gravity flow device and the welding allowance, demarcating the area to be cut on the hull, and extending the boundary of the area to be cut to the adjacent supporting members of the hull to ensure the structural integrity of the hull segment after cutting; Cutting along the boundary of the area to be cut to separate the area to be cut from the hull to form an independent hull section including the installation position; Holes are opened on the outer surface of the hull segments, flow channels are welded at the holes, and metal frames are welded between the flow channels and the hull segments, thereby completing the fabrication and installation of the gravity flow device; The hull sections with integrated gravity flow devices are repositioned to the cut notches in the hull, butt-welded, and the quality and strength of the welds are tested to ensure that the hull structure is restored to the original design load standard.

2. The construction method for newly adding or modifying a gravity flow device for a ship according to claim 1, characterized in that: The metal frame includes ring ribs, transverse ribs and longitudinal brackets, which are welded to each other to form a three-dimensional grid-like support frame, and the metal frame is welded and fixed to the outer wall of the flow channel; The inner cavity space enclosed by the metal frame is filled with a light pressure-resistant material to cover the flow channel, and an outer shell plate is formed on the outer surface of the material. The outer shell plate is connected to the hull segment and the metal frame through embedded parts.

3. The construction method for newly adding or modifying a gravity flow device on a ship according to claim 1, characterized in that: The area to be cut is a rectangular segment, the size of which envelops the entire gravity flow device, and a reinforcement structure is pre-welded on the inner surface of the segment before cutting to prevent deformation during cutting; After the welding is restored, the reinforcement structure on the inner surface of the segment is cut and removed, and the removed area is repaired by welding.

4. The construction method for newly adding or modifying a gravity flow device for a ship according to claim 1 or 3, characterized in that: The cutting adopts a plasma cutting or laser cutting process, and the edge of the cut is beveled during or after the cutting process to meet the subsequent welding requirements.

5. The construction method for newly adding or modifying a gravity flow device on a ship according to claim 1, characterized in that: After the hull is cut into sections, it is transported to a gravity flow device processing workshop and fixed on a clamping fixture so that the gravity flow device installation surface faces upward to optimize the construction posture.

6. The construction method for newly adding or modifying a gravity flow device on a ship according to claim 2, characterized in that: The gravity flow device is manufactured and constructed in a workshop to meet the construction conditions of metal frame welding, weld non-destructive testing conditions, inner cavity lightweight pressure-resistant material construction conditions, and composite material outer shell plate construction conditions.

7. The construction method for newly adding or modifying a gravity flow device on a ship according to claim 1 or 2, characterized in that: After the self-flow device is manufactured, its outer surface is machined or polished in a workshop to ensure that the accuracy of the outer line meets the design tolerance requirements.

8. The construction method for newly adding or modifying a gravity flow device on a ship according to claim 1 or 3, characterized in that: The butt welding adopts a multi-layer and multi-pass welding process, and the heat input is monitored during welding to avoid thermal damage to the composite shell plate and the filling material; The weld inspection includes X-ray non-destructive testing and tightness testing to ensure that there are no pores, cracks or leaks in the weld area.

9. The construction method for newly adding or modifying a gravity flow device on a ship according to claim 2, characterized in that: The shell plate is made of glass fiber reinforced plastic composite material, and its curing temperature curve includes the following steps: first, starting from 40°C, uniformly heating to 80°C within 2 hours; then maintaining a constant temperature at 80°C for 4 hours; and finally naturally cooling to below 40°C to complete demoulding.

10. The construction method for newly adding or modifying a gravity flow device on a ship according to claim 2, characterized in that: The lightweight pressure-resistant material is a closed-cell polyurethane foam or epoxy glass microbead composite material with a density of 80 to 500 kg / m 3 , the ambient temperature during filling is controlled at 20 to 30℃.

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