Polymer compensation flange connection structure and construction method

Abstract

The application discloses a high polymer compensation flange connecting structure and a construction method. In view of the problems of large cumulative construction error of a high polymer polypropylene pipe of a ship aquaculture seawater system, inability to weld in a narrow cabin, poor working condition adaptability, easy lifting interference, low construction precision and work efficiency, the application designs two types of compensation connecting nodes suitable for different pipe diameters and gap working conditions. The application eliminates assembly errors through customizable variable-thickness compensation components, cooperates with an end face overlapping sealing structure, and realizes welding-free sealed butt joint of the pipeline. At the same time, a standardized construction process is provided, pipeline negative tolerance lofting, differential node matching and gap actual measurement quantitative compensation processing methods are adopted, and the traditional hot melting welding correction process is abandoned. The application effectively avoids lifting interference, breaks through the construction limitation of a narrow space, greatly improves the pipeline assembly precision and sealing reliability, has high construction efficiency and strong working condition adaptability, and is suitable for high polymer material pipeline joint construction of a ship aquaculture seawater system.

Description

Technical Field

[0001] This invention belongs to the field of marine pipeline installation technology, specifically relating to a polymer compensating flange connection structure and construction method. Background Technology

[0002] To meet the corrosion resistance requirements of marine aquaculture systems and achieve lightweight hull design, high-polymer polypropylene (PP) pipes are now widely used in shipbuilding to replace traditional metal pipes. Due to their advantages of seawater corrosion resistance, light weight, and high cost-effectiveness, their application in aquaculture piping systems is gradually expanding. However, constrained by the overall structural strength of the aquaculture tank, the pipes laid longitudinally and transversely within the system must penetrate the hull structure through openings. Most of these openings have narrow gaps between the pipes and the outer wall, creating numerous confined assembly conditions. Furthermore, the fixed specifications of PP pipes and accessories result in poor on-site adaptability, making pipe installation and alignment in and out of the tank difficult. Additionally, pipe construction must strictly match the overall rhythm of the hull's segmented construction and assembly, imposing stringent construction constraints.

[0003] Currently, the segmented assembly of polypropylene pipes for marine aquaculture seawater systems commonly employs the traditional method of direct connection using fixed-specification flanges and on-site hot-melt welding for correction. This is the mainstream construction approach in the industry. This process relies on standardized pipe fittings for matching and on-site hot-melt welding to correct installation deviations. It can meet the basic assembly requirements for piping in conventional, spacious compartments and is compatible with traditional ship piping construction procedures.

[0004] However, in actual construction, traditional construction techniques have many inherent technical defects, making them difficult to adapt to the current requirements of refined and efficient shipbuilding. First, errors in hull structure construction and pipe prefabrication can easily accumulate, causing pipe ends to protrude from hull section dividing lines, directly hindering hull section assembly and hoisting operations, and interfering with the overall construction progress. Second, the large size of the hot-melt welding equipment for high-polymer polypropylene pipes prevents welding operations in narrow compartments, making in-cabin pipe butt welding impossible and severely limiting construction. Finally, traditional techniques lack effective error compensation mechanisms, failing to offset gap deviations generated during construction, prefabrication, and on-site installation. After pipe butt welding, problems such as misalignment, inadequate end-face sealing, and stress concentration are prone to occur. Furthermore, a single structure cannot adapt to the complex working conditions of varying pipe diameters and gaps within the compartment, resulting in poor adaptability, low installation accuracy, significant pipe leakage risks, and low overall construction efficiency. In summary, traditional closure pipe construction technology can no longer meet the current production design and efficient construction requirements of marine aquaculture systems. There is an urgent need to develop a polymer compensation flange construction method that can solve the above-mentioned technical defects. Summary of the Invention

[0005] The purpose of this invention is to provide a polymer compensating flange connection structure and construction method to solve the technical problems in the construction of polymer polypropylene pipes for marine aquaculture seawater systems, such as low positioning accuracy of pipelines entering the cabin, difficulty in meeting the requirements for rapid assembly of sections, inability of traditional closure processes to eliminate cumulative errors in construction and prefabrication, poor adaptability to working conditions, and difficulty in connecting pipelines in narrow spaces, as well as low installation accuracy and construction efficiency. By matching a special compensating connection structure and optimizing the construction process, the accuracy of pipeline closure and construction efficiency are improved.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a polymer compensating flange connection structure for the segmented joining and connection of polymer polypropylene pipes in a marine aquaculture seawater system. It includes two types of compensating connection nodes adapted to different installation conditions: a first compensating connection node and a second compensating connection node. Each compensating connection node includes a loose flange, a polymer polypropylene adapter, a variable thickness compensating component, a sealing component, and a locking component. The polymer polypropylene adapter is heat-fused to the polymer polypropylene pipe, and a variable thickness compensating component is clamped between two oppositely joined polymer polypropylene adapters. The sealing component is fitted and clamped between the mating end faces of the variable thickness compensating component and the polymer polypropylene adapter, forming an end-face overlapping sealing structure. The locking component penetrates the polymer polypropylene adapter, the variable thickness compensating component, and the sealing component, locking each mating component through axial compression to achieve sealing and fixing of the pipeline connection. The thickness of the variable thickness compensating component can be customized according to the actual installation gap on site.

[0007] Furthermore, the first compensation connection node is a node structure adapted to small and medium pipe diameters of DN100~DN600. The variable thickness compensation component of the first compensation connection node adopts a first high molecular weight polypropylene compensation gasket, the sealing component adopts a first rubber sealing gasket, the locking component adopts a first bolt and nut pair, the loose flange adopts a first loose flange, and the high molecular weight polypropylene adapter adopts a first high molecular weight polypropylene adapter. The first high molecular weight polypropylene adapter has a pipe body, and the outer wall of the end of the pipe body away from the high molecular weight polypropylene pipe is integrally formed with an annular shoulder. The pipe body and the high molecular weight polypropylene pipe are heat-fused and welded together. The first loose flange is movably sleeved on the outside of the pipe body and is pressed and fitted against the outer end face of the annular shoulder by the first bolt and nut pair. The first high molecular weight polypropylene compensation gasket is sandwiched between the annular shoulders of the two sets of oppositely arranged first high molecular weight polypropylene adapters. The first rubber sealing gasket is stacked between the annular shoulder and the first high molecular weight polypropylene compensation gasket to form an end face superimposed sealing structure. The first loose flange has a mounting hole for the first bolt and nut pair to pass through and assemble.

[0008] Furthermore, annular watertight lines are provided on the mating end faces of the first polymer polypropylene compensation gasket and the annular shoulder.

[0009] Furthermore, the components of the first compensation connection node adopt a standardized specification matching design. The specific specifications are as follows: the first loose flange, the first high molecular weight polypropylene adapter, and the first high molecular weight polypropylene compensation gasket are all nominal diameter DN400 and nominal pressure PN10 specifications; the first rubber sealing gasket is a nominal diameter DN400 EPDM EPDM rubber gasket; and the first bolt and nut pair is an M20 specification hexagonal bolt.

[0010] Furthermore, the second compensation connection node is a node structure adapted to extremely narrow working conditions with large pipe diameters of DN700~DN800 and a structural opening and flange gap of ≤10mm. The variable thickness compensation component of the second compensation connection node adopts a second high-molecular-weight polypropylene compensation flange, the sealing assembly adopts a second rubber sealing gasket, the locking assembly adopts a second bolt and nut pair, the loose flange adopts a second loose flange, and the high-molecular-weight polypropylene adapter adopts a second high-molecular-weight polypropylene adapter; the second high-molecular-weight polypropylene adapter is provided with a pipe body, and the outer wall of the end of the pipe body away from the high-molecular-weight polypropylene pipe is integrally formed circumferentially. An annular shoulder is provided. The pipe body and the high-molecular-weight polypropylene pipe are heat-fused and welded together. The second loose flange is movably sleeved on the outside of the pipe body and is pressed against the outer end face of the annular shoulder by the second bolt and nut pair. A second high-molecular-weight polypropylene compensation flange is sandwiched between the annular shoulders of the two sets of oppositely arranged second high-molecular-weight polypropylene adapters. The second rubber sealing gasket is stacked between the annular shoulder and the second high-molecular-weight polypropylene compensation flange to form an end face superimposed sealing structure. The second loose flange, the second high-molecular-weight polypropylene compensation flange, the second rubber sealing gasket, and the annular shoulder are all provided with corresponding mounting holes for the second bolt and nut pair to pass through and assemble.

[0011] Furthermore, annular watertight lines are provided on the mating end faces of the second polymer polypropylene compensation flange and the annular shoulder.

[0012] Furthermore, the components of the second compensation connection node adopt a standardized specification matching design. The specific specifications are as follows: the second loose flange, the second high molecular weight polypropylene adapter, and the second high molecular weight polypropylene compensation flange are all nominal diameter DN700 and nominal pressure PN10 specifications; the second rubber sealing gasket is a nominal diameter DN700 EPDM EPDM rubber gasket; and the second bolt and nut pair is an M24 specification hexagon socket head cap bolt.

[0013] Furthermore, the polymer polypropylene adapter, the variable thickness compensation component, and the polymer polypropylene pipe are integrated into a single structure using the same polypropylene material.

[0014] Secondly, the present invention also provides a construction method for a polymer compensating flange, which uses the above-mentioned polymer compensating flange connection structure to install pipelines in a marine aquaculture seawater system, including the following construction steps: S1. Pipeline pretreatment and node planning: Based on the layout of the polymer polypropylene pipes in the ship's aquaculture tank, the pipeline layout of the polymer polypropylene pipes in the aquaculture seawater system is planned, precisely positioned and cut to a fixed length, and the construction nodes for segmented closure of the pipeline are determined. S2. Precise layout design of pipeline: The overall layout of pipeline is based on the coordinates of the ship's through-hull parts. For the high molecular weight polypropylene pipes arranged across the segmentation lines of the ship's sections, negative tolerance layout is used for the pipe ends to prefabricate and reserve the pipeline assembly error compensation margin. S3. Segmented Adaptive Installation: Based on the different construction states of the hull segments (normal, horizontal, and reverse), prefabricated high-polymer polypropylene pipes of corresponding numbers are classified and installed in the compartments, and protective treatment is applied to the prefabricated pipes. S4. Matching connection nodes according to pipe diameter: After the hull sections are assembled and installed, match the corresponding compensation connection nodes according to the pipe diameter specifications; small and medium diameter pipes from DN100 to DN600 use the first compensation connection node, and large diameter pipes from DN700 to DN800 with small gaps use the second compensation connection node. S5. Precise Compensation Installation of the First Node: Perform multi-point circumferential detection on the closing installation position of the first compensation connection node, collect a set of L1 installation gap data every 90°, select the minimum value among the four sets of data, and calculate the final processing thickness of the first polymer polypropylene compensation gasket according to the formula H1=L1-2t, where t is the preset compensation reference thickness; perform machining on the first polymer polypropylene compensation gasket according to the calculated thickness to complete the sealing assembly of the first node pipeline. S6. Precise Compensation Installation of the Second Node: Perform multi-point circumferential detection on the closing installation position of the second compensation connection node, collect a set of L2 installation gap data every 90°, select the minimum value among the four sets of data, and calculate the final processing thickness of the second polymer polypropylene compensation flange according to the formula H2=L2-2t, where t is the preset compensation reference thickness; perform machining on the second polymer polypropylene compensation flange according to the calculated thickness to complete the sealing assembly of the second node pipeline. S7. Standardized Construction Across the Entire Area: Repeat the above steps to complete the segmented assembly and installation of all high-polymer polypropylene pipes in the entire ship's aquaculture seawater system.

[0015] Furthermore, in step S2, the ends of the pipelines arranged across the hull segmentation lines are prefabricated using a negative 10mm tolerance layout, leaving room for pipeline assembly error compensation.

[0016] Compared with existing technologies, the polymer compensation flange connection structure and construction method provided by this invention specifically solve the core technical problem of segmented assembly construction of polymer polypropylene pipes in marine aquaculture seawater systems, and make up for the inherent defects of traditional construction technologies. The specific beneficial effects are as follows: At the structural level, this invention features a unique dual-condition adaptable compensation connection structure system. It utilizes two types of compensation connection nodes adapted to different pipe diameters and assembly gaps, combined with loose flanges, high-polymer polypropylene adapters, customizable variable-thickness compensation components, sealing components, and locking components to form an integrated assembly structure. Compared to traditional fixed flange docking structures, this invention adds variable-thickness compensation components whose thickness can be customized according to the actual gap on site. This effectively eliminates multiple cumulative errors generated during hull construction, pipeline prefabrication, and on-site assembly, solving the technical drawbacks of traditional flange structures, such as lack of error compensation capability, limited adaptability to operating conditions, and poor versatility. Simultaneously, the use of a high-polymer polypropylene adapter and a pipeline thermofusion integral molding structure, along with end-face overlapping sealing and axial compression locking assembly, allows for seamless pipeline docking without on-site welding, significantly improving the accuracy of pipeline segment docking, adaptability to operating conditions, and overall sealing stability during service.

[0017] At the construction method level, this invention relies on the aforementioned dedicated compensation connection structure to construct a complete standardized pipeline assembly process system adapted to the segmented construction mode of ships. Through pre-planning of pipelines, negative tolerance layout with pre-reserved compensation margins, segmented and categorized entry into the cabin, matching of nodes with different working conditions, quantitative compensation processing for gap measurements, and standardized full-area assembly, the entire process is optimized, completely eliminating the outdated construction mode that relies on on-site hot-melt welding to correct assembly deviations. This invention avoids the segmented hoisting interference problem caused by pipe end protrusion from the process source, adapting to the modern construction rhythm of rapid assembly and installation of hull segments, and completely solving industry pain points such as the inability to access equipment in narrow cabins, limited welding construction, and frequent welding defects. Through circumferential multi-point gap detection and minimum value benchmark precise processing compensation methods, various cumulative assembly errors are eliminated in all aspects, significantly improving the construction accuracy and efficiency of high-polymer polypropylene pipe segmented assembly, achieving weld-free, high-precision, standardized, and sealed assembly operations for ship aquaculture seawater system pipelines. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0019] Figure 1 This is a schematic diagram showing the arrangement of compensating connection nodes during the segmented assembly and docking construction of high molecular weight polypropylene pipes for aquaculture seawater systems. Figure 2 This is a cross-sectional view of the sealing structure of the first compensation connection node end face in an embodiment of the present invention; Figure 3This is a cross-sectional view of the sealing structure of the second compensation connection node end face in an embodiment of the present invention.

[0020] Marked in the image: Polypropylene tube 10; First compensation connection node 20; Second compensation connection node 30; First loose flange 21; First high molecular weight polypropylene adapter 22; First high molecular weight polypropylene compensation gasket 23; First rubber sealing gasket 24; First bolt and nut pair 25; Annular shoulder 26; Mounting hole 27; Annular watertight line 28; Second loose flange 31; Second high molecular weight polypropylene adapter 32; Second high molecular weight polypropylene compensation flange 33; Second rubber sealing gasket 34; Second bolt and nut pair 35; Annular shoulder 36; Mounting hole 37; Annular watertight line 38. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0025] like Figures 1 to 3As shown, this embodiment of the invention provides a polymer compensation flange connection structure suitable for the segmented closure and connection construction of polymer polypropylene pipes 10 in marine aquaculture seawater systems. This connection structure includes two types of compensation connection nodes adapted to different installation conditions: a first compensation connection node 20 and a second compensation connection node 30, which can respectively adapt to conventional small-diameter pipe conditions and large-diameter narrow-gap pipe conditions. Both types of compensation connection nodes include a loose flange (marked as 21 or 31 in the figure), a polymer polypropylene adapter (marked as 22 or 32 in the figure), a variable thickness compensation component (marked as 23 or 33 in the figure), a sealing component (marked as 24 or 34 in the figure), and a locking component (marked as 25 or 35 in the figure). The polymer polypropylene adapter and the polymer polypropylene pipe 10 are fixed as a single unit using a heat-fusion bonding method. A variable thickness compensation component is sandwiched between the two sets of opposing polymer polypropylene adapters, and the sealing component is fitted and clamped between the mating end faces of the variable thickness compensation component and the polymer polypropylene adapter, forming an end-face overlapping sealing structure. The locking assembly runs through the polymer polypropylene adapter, the variable thickness compensation component, and the sealing assembly. It locks the relative positions of each mating component through axial compression, achieving reliable sealing and fixed assembly at the pipe joint. The variable thickness compensation component of this invention can be customized in thickness according to the actual assembly gaps at the construction site, effectively offsetting the cumulative assembly errors generated during hull construction, pipe prefabrication, and on-site installation. It eliminates the need for hot-melt welding in confined spaces, enabling high-precision, airtight pipe connections and adapting to the complex construction conditions of segmented shipbuilding.

[0026] In this embodiment, as Figure 2As shown, the first compensation connection node 20 is suitable for conventional installation of small-diameter pipelines from DN100 to DN600. It is mainly composed of a first loose flange 21, a first high-molecular-weight polypropylene adapter 22, a first high-molecular-weight polypropylene compensation gasket 23, a first rubber sealing gasket 24, and a first bolt and nut assembly 25. The first high-molecular-weight polypropylene adapter 22 is a tubular structure. An annular shoulder 26 is integrally formed on the outer wall of the end furthest from the high-molecular-weight polypropylene pipe 10. The pipe body of the first high-molecular-weight polypropylene adapter 22 is heat-fused to the high-molecular-weight polypropylene pipe 10 to form an integral structure, ensuring the integrity and stability of the connection structure. The first loose flange 21 is movably fitted onto the outside of the pipe body of the first high-molecular-weight polypropylene adapter 22, allowing free axial sliding and circumferential rotation. It is pressed against the outer end face of the annular shoulder 26 by the first bolt and nut assembly 25 to achieve axial fixation. Two sets of opposing first high-molecular-weight polypropylene adapters 22 have annular shoulders 26 clamping a first high-molecular-weight polypropylene compensating gasket 23. A first rubber sealing gasket 24 is stacked between the mating end faces of the annular shoulders 26 and the first high-molecular-weight polypropylene compensating gasket 23, forming a stable end-face stacking sealing structure to meet the watertight sealing and assembly fixing requirements of small and medium diameter pipe connections. The first loose flange 21 has mounting holes 27 for the first bolt and nut assembly 25 to pass through. The mounting holes for the first high-molecular-weight polypropylene compensating flange 23, the first rubber sealing gasket 24, and the annular shoulders 26 may or may not be provided depending on the width of the mating end faces of the components.

[0027] As a preferred embodiment, annular watertight lines 28 are provided on the mating surfaces of the annular shoulders 26 of the first polymer polypropylene compensation gasket 23 and the first polymer polypropylene adapter 22. By adding annular watertight lines 28, the tightness of the fit between the mating surfaces and the first rubber sealing gasket 24 can be effectively improved, the technical problems of poor sealing and easy leakage can be resolved, and the sealing reliability and long-term service stability of the first compensation connection node 20 can be enhanced.

[0028] Taking the application of conventional DN400 small-diameter pipelines as an example, the components of the first compensation connection node 20 adopt standardized specification matching design to adapt to the assembly load and sealing requirements of conventional small-diameter pipelines. The specific specifications are as follows: the first loose flange 21, the first high-molecular-weight polypropylene adapter 22, and the first high-molecular-weight polypropylene compensation gasket 23 all adopt the nominal diameter DN400 and nominal pressure PN10 specifications; the first rubber sealing gasket 24 adopts the EPDM ethylene propylene diene monomer rubber gasket adapted to the DN400 pipe diameter, which has excellent seawater corrosion resistance and sealing performance; the first bolt and nut pair 25 adopts the M20 specification hexagonal bolt, which has high fastening strength and good assembly convenience, and is suitable for conventional in-cabin assembly and construction conditions.

[0029] In this embodiment, as Figure 3As shown, the second compensating connection node 30 is suitable for extremely narrow installation conditions where the pipe diameter is DN700~DN800 and the gap between the structural opening and the flange is ≤10mm. It is mainly composed of a second loose flange 31, a second high-molecular-weight polypropylene adapter 32, a second high-molecular-weight polypropylene compensating flange 33, a second rubber sealing gasket 34, and a second bolt and nut pair 35. The second high-molecular-weight polypropylene adapter 32 is also a tubular structure. The outer wall of the end away from the high-molecular-weight polypropylene pipe 10 has an annular shoulder 36 integrally formed around its circumference. The pipe body of the second high-molecular-weight polypropylene adapter 32 and the high-molecular-weight polypropylene pipe 10 are heat-fused and welded into an integral structure to ensure the integrity and stability of the connection structure. The second loose flange 31 is movably sleeved on the outside of the pipe body of the second high-molecular-weight polypropylene adapter 32, and can slide freely axially and rotate circumferentially. It is pressed against the outer end face of the annular shoulder 36 by the second bolt and nut pair 35 to achieve axial fixed positioning. Two sets of opposing second high-molecular-weight polypropylene adapters 32 are sandwiched between their annular shoulders 36, forming a second high-molecular-weight polypropylene compensation flange 33. A second rubber sealing gasket 34 is stacked between the mating end faces of the annular shoulders 36 and the second high-molecular-weight polypropylene compensation gasket, creating a stable end-face overlapping sealing structure. Simultaneously, mounting holes 37 are provided at corresponding positions on the second high-molecular-weight polypropylene compensation flange 33, the second rubber sealing gasket 34, and the annular shoulders 36, allowing the second bolt and nut assembly 35 to pass through and be assembled. This adapts to the construction conditions of bolt tightening operations in confined spaces, effectively solving the problem of difficult pipe connection construction for large-diameter, small-gap pipelines.

[0030] As a preferred embodiment, the mating end faces of the annular shoulder 36 of the second polymer polypropylene compensation flange 33 and the second polymer polypropylene adapter 32 are also provided with an annular watertight line 38. By adding the annular watertight line 38, the tightness of the fit between the mating end face and the second rubber sealing gasket 34 can be effectively improved, the technical problems of poor sealing and easy leakage can be improved, and the sealing reliability and long-term service stability of the second compensation connection node 30 can be enhanced.

[0031] Taking the application of DN700 large-diameter narrow-gap pipelines as an example, the components of the second compensation connection node 30 adopt standardized specifications for matching the application of DN700 large-diameter narrow-gap pipelines. The specific specifications are as follows: the second loose flange 31, the second high-molecular-weight polypropylene adapter 32, and the second high-molecular-weight polypropylene compensation flange 33 all adopt nominal diameter DN700 and nominal pressure PN10 specifications; the second rubber sealing gasket 34 adopts EPDM EPDM rubber gaskets that are suitable for DN700 pipe diameter and are suitable for long-term seawater immersion service environment; the second bolt and nut pair 35 adopts M24 specification hexagonal bolts, which are suitable for tightening operations in narrow spaces, with uniform tightening torque and strong connection reliability, meeting the load-bearing and sealing requirements of large-diameter pipelines.

[0032] It should be noted that the polymer polypropylene adapter, the variable thickness compensation component, and the polymer polypropylene pipe 10 are all made of the same polypropylene material and are integrated into a single structure. The material properties, coefficient of thermal expansion and contraction, and mechanical properties of each component are highly uniform, which can effectively avoid defects such as stress concentration, inconsistent thermal deformation, and loose connection caused by the docking of dissimilar components. This significantly improves the integrity, corrosion resistance, and structural stability of the pipeline docking structure, making it suitable for the high humidity and complex temperature change seawater service environment of ship aquaculture tanks, and effectively extending the overall service life of the pipeline system.

[0033] Based on the aforementioned polymer compensation flange connection structure, this invention provides a construction method for polymer polypropylene pipe 10 in a marine aquaculture seawater system. Through optimized processes including pre-error compensation layout, precise on-site gap detection, customized component processing, and differentiated node matching assembly, it solves the technical problems of low positioning accuracy in traditional pipeline assembly, limited construction in confined spaces, difficulty in eliminating accumulated errors, and low construction efficiency. This method perfectly matches the rapid assembly and installation rhythm of ship sections. The specific construction steps are as follows: S1. Pipeline Pre-treatment and Node Planning: Based on the overall layout plan of the polymer polypropylene pipe 10 in the ship aquaculture tank, the pipeline layout of the polymer polypropylene pipe 10 in the aquaculture seawater system is planned, precisely positioned and cut to a fixed length. The construction nodes for the closure of each pipeline segment are clarified, and different pipe diameters and gap conditions are distinguished to provide a preliminary foundation for subsequent differentiated assembly construction.

[0034] S2. Precise Pipeline Laying-out Design: The overall pipeline laying-out is based on the coordinates of the hull's through-hull components. For the high-polymer polypropylene pipe 10 arranged across the hull segment division lines, negative tolerance laying-out prefabrication is adopted for the pipe ends, reserving a margin for pipeline assembly error compensation. Specifically, the pipe ends arranged across the segment division lines are laid-out prefabricated with a negative 10mm tolerance, offsetting the cumulative errors caused by hull construction and pipeline prefabrication from the source, and completely avoiding the segment lifting interference problem caused by pipe end protrusion.

[0035] S3. Segmented Adaptation and Installation in the Cabin: Based on the different construction states of the hull segments (normal, horizontal, and reverse), the prefabricated high-polymer polypropylene pipes of corresponding numbers are transported into the cabin and installed in place according to 10 categories. The prefabricated pipes are protected to avoid on-site bumps, displacement, and contamination, and to ensure the integrity of the prefabrication accuracy of the pipes.

[0036] S4. Matching connection nodes according to pipe diameter: After the hull sections are assembled and installed, corresponding compensation connection nodes are matched according to the differences in pipe diameter specifications. Among them, small and medium diameter pipes from DN100 to DN600 are adapted to the first compensation connection node 20, and large diameter pipes from DN700 to DN800 with small gaps are adapted to the second compensation connection node 30, so as to achieve precise matching of working conditions.

[0037] S5. Precise Compensation Installation of the First Node: A multi-point circumferential inspection is performed on the closing installation position of the first compensation connection node 20. A set of L1 installation gap data is collected every 90°. The minimum value among the four sets of data is selected as the processing benchmark. The final processing thickness of the first polymer polypropylene compensation gasket 23 is calculated using the formula H1=L1-2t, where t is the preset compensation benchmark thickness. The first polymer polypropylene compensation gasket 23 is precision machined according to the calculated thickness. After machining, alignment and assembly are performed. The watertight line structure on the end face is used to correct the centering deviation of the inclined end face, completing the sealed assembly of the first node pipeline and ensuring a tight seal at the connection point without any leakage risks.

[0038] S6. Precise Compensation Installation of the Second Node: Multi-point circumferential detection is performed on the closing installation position of the second compensation connection node 30. A set of L2 installation gap data is collected every 90°. The minimum value among the four sets of data is selected as the processing benchmark. The final processing thickness of the second polymer polypropylene compensation flange 33 is calculated using the formula H2=L2-2t, where t is the preset compensation benchmark thickness. Precision machining of the second polymer polypropylene compensation flange 33 is completed based on the calculated thickness, adapting to the high-precision assembly requirements of narrow spaces, and completing the sealing assembly of the second node pipeline.

[0039] S7. Standardized Construction Across the Entire Area: Repeat the above construction steps to complete the segmented assembly of all high-polymer polypropylene pipes 10 in the entire ship's aquaculture seawater system. After the construction is completed, conduct a unified pipeline tightness test to ensure that all joints are reliably sealed and free of leakage defects, thus ensuring the long-term stable operation of the pipeline system.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A polymer-compensated flange connection structure, characterized in that, This invention relates to a segmented joining and connection method for high-molecular-weight polypropylene (PP) pipes used in marine aquaculture seawater systems. It includes two types of compensating connection nodes adapted to different installation conditions: a first compensating connection node and a second compensating connection node. Each compensating connection node includes a loose flange, a PP adapter, a variable-thickness compensating component, a sealing component, and a locking component. The PP adapter is heat-fused to the PP pipe, and a variable-thickness compensating component is clamped between two mating PP adapters. The sealing component is fitted between the mating end faces of the variable-thickness compensating component and the PP adapter, forming an end-face overlapping seal structure. The locking component penetrates the PP adapter, the variable-thickness compensating component, and the sealing component, locking each mating component through axial compression to achieve sealing and fixation of the pipe connection. The variable-thickness compensating component can be customized in thickness according to the actual installation gap on site.

2. The polymer compensation flange connection structure according to claim 1, characterized in that, The first compensation connection node is a node structure adapted to small and medium pipe diameters from DN100 to DN600. The variable thickness compensation component of the first compensation connection node adopts a first high-molecular-weight polypropylene compensation gasket, the sealing component adopts a first rubber sealing gasket, the locking component adopts a first bolt and nut pair, the loose flange adopts a first loose flange, and the high-molecular-weight polypropylene adapter adopts a first high-molecular-weight polypropylene adapter. The first high-molecular-weight polypropylene adapter has a pipe body, and the outer wall of the end of the pipe body away from the high-molecular-weight polypropylene pipe is integrally formed with an annular shoulder. The pipe body and the high-molecular-weight polypropylene pipe are heat-fused and welded together. The first loose flange is movably sleeved on the outside of the pipe body and is pressed and fitted against the outer end face of the annular shoulder by the first bolt and nut pair. A first high-molecular-weight polypropylene compensation gasket is sandwiched between the annular shoulders of two sets of oppositely arranged first high-molecular-weight polypropylene adapters. The first rubber sealing gasket is stacked between the annular shoulder and the first high-molecular-weight polypropylene compensation gasket to form an end face overlapping sealing structure. The first loose flange has a mounting hole for the first bolt and nut pair to pass through and assemble.

3. The polymer compensation flange connection structure according to claim 2, characterized in that, The first polymer polypropylene compensation gasket and the annular shoulder are both provided with annular watertight lines on their mating end faces.

4. The polymer compensation flange connection structure according to claim 2, characterized in that, The components of the first compensation connection node are designed with standardized specifications. The specific specifications are as follows: the first loose flange, the first high molecular weight polypropylene adapter and the first high molecular weight polypropylene compensation gasket are all nominal diameter DN400 and nominal pressure PN10 specifications; the first rubber sealing gasket is a nominal diameter DN400 EPDM EPDM rubber gasket; and the first bolt and nut pair is an M20 specification hexagonal bolt.

5. The polymer compensation flange connection structure according to claim 1, characterized in that, The second compensation connection node is a node structure adapted to extremely narrow working conditions with large pipe diameters of DN700~DN800 and a structural opening and flange gap of ≤10mm. The variable thickness compensation component of the second compensation connection node adopts a second high-molecular-weight polypropylene compensation flange, the sealing assembly adopts a second rubber sealing gasket, the locking assembly adopts a second bolt and nut pair, the loose flange adopts a second loose flange, and the high-molecular-weight polypropylene adapter adopts a second high-molecular-weight polypropylene adapter; the second high-molecular-weight polypropylene adapter has a pipe body, and the outer wall of the end of the pipe body away from the high-molecular-weight polypropylene pipe is integrally formed with an annular stop. The shoulder is formed by hot-melt welding of the pipe body and the high-molecular-weight polypropylene pipe. The second loose flange is movably sleeved on the outside of the pipe body and is pressed against the outer end face of the annular shoulder by the second bolt and nut pair. A second high-molecular-weight polypropylene compensation flange is sandwiched between the annular shoulders of the two sets of oppositely arranged second high-molecular-weight polypropylene adapters. The second rubber sealing gasket is stacked between the annular shoulder and the second high-molecular-weight polypropylene compensation flange to form an end face superimposed sealing structure. The second loose flange, the second high-molecular-weight polypropylene compensation flange, the second rubber sealing gasket, and the annular shoulder are all provided with corresponding mounting holes for the second bolt and nut pair to pass through and assemble.

6. The polymer compensation flange connection structure according to claim 5, characterized in that, The second polymer polypropylene compensation flange and the annular shoulder are both provided with annular watertight lines on their mating end faces.

7. The polymer compensation flange connection structure according to claim 5, characterized in that, The components of the second compensation connection node are designed with standardized specifications. The specific specifications are as follows: the second loose flange, the second high molecular weight polypropylene adapter and the second high molecular weight polypropylene compensation flange are all nominal diameter DN700 and nominal pressure PN10 specifications; the second rubber sealing gasket is a nominal diameter DN700 EPDM EPDM rubber gasket; and the second bolt and nut pair is an M24 specification hexagon socket head cap bolt.

8. The polymer compensation flange connection structure according to claim 1, characterized in that, The polymer polypropylene adapter, the variable thickness compensation component, and the polymer polypropylene pipe are integrated into a single structure using the same polypropylene material.

9. A construction method for a polymer compensation flange, characterized in that, The installation of marine aquaculture seawater system pipelines using the polymer compensating flange connection structure described in any one of claims 1 to 8 includes the following construction steps: S1. Pipeline pretreatment and node planning: Based on the layout of the polymer polypropylene pipes in the ship's aquaculture tank, the pipeline layout of the polymer polypropylene pipes in the aquaculture seawater system is planned, precisely positioned and cut to a fixed length, and the construction nodes for segmented closure of the pipeline are determined. S2. Precise layout design of pipeline: The overall layout of pipeline is based on the coordinates of the ship's through-hull parts. For the high molecular weight polypropylene pipes arranged across the segmentation lines of the ship's sections, negative tolerance layout is used for the pipe ends to prefabricate and reserve the pipeline assembly error compensation margin. S3. Segmented Adaptive Installation: Based on the different construction states of the hull segments (normal, horizontal, and reverse), prefabricated high-polymer polypropylene pipes of corresponding numbers are classified and installed in the compartments, and protective treatment is applied to the prefabricated pipes. S4. Matching connection nodes according to pipe diameter: After the hull sections are assembled and installed, match the corresponding compensation connection nodes according to the pipe diameter specifications; small and medium diameter pipes from DN100 to DN600 use the first compensation connection node, and large diameter pipes from DN700 to DN800 with small gaps use the second compensation connection node. S5. Precise Compensation Installation of the First Node: Perform multi-point circumferential detection on the closing installation position of the first compensation connection node, collect a set of L1 installation gap data every 90°, select the minimum value among the four sets of data, and calculate the final processing thickness of the first polymer polypropylene compensation gasket according to the formula H1=L1-2t, where t is the preset compensation reference thickness; perform machining on the first polymer polypropylene compensation gasket according to the calculated thickness to complete the sealing assembly of the first node pipeline. S6. Precise Compensation Installation of the Second Node: Perform multi-point circumferential detection on the closing installation position of the second compensation connection node, collect a set of L2 installation gap data every 90°, select the minimum value among the four sets of data, and calculate the final processing thickness of the second polymer polypropylene compensation flange according to the formula H2=L2-2t, where t is the preset compensation reference thickness; perform machining on the second polymer polypropylene compensation flange according to the calculated thickness to complete the sealing assembly of the second node pipeline. S7. Standardized Construction Across the Entire Area: Repeat the above steps to complete the segmented assembly and installation of all high-polymer polypropylene pipes in the entire ship's aquaculture seawater system.

10. The construction method of the polymer compensation flange according to claim 9, characterized in that, In step S2, the ends of the pipelines arranged across the hull segment division lines are prefabricated using a negative 10mm tolerance layout, leaving room for pipeline assembly error compensation.

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