Underwater special equipment corrosion-resistant insulation cabin bottom embedded pipeline system and installation method thereof

Abstract

The invention provides a corrosion-resistant insulating cabin bottom pre-embedded pipeline system of underwater special equipment and a mounting method of the corrosion-resistant insulating cabin bottom pre-embedded pipeline system. The corrosion-resistant insulating cabin bottom embedded pipeline system of the underwater special equipment comprises a metal cabin penetration piece, a PEEK material embedded pipe, a sealing gasket and a fastener, the metal cabin penetration piece is arranged on the cabin wall in a penetrating mode and is connected with the cabin wall in a welded mode, and a flange is arranged at the end, located on the outer side of the cabin wall, of the metal cabin penetration piece; a flange is arranged at the end, facing the metal penetration piece, of the PEEK material embedded pipe, a sealing gasket is arranged between the flange of the metal penetration piece and the flange of the PEEK material embedded pipe, a fastener penetrates through the flange of the metal penetration piece and the flange of the PEEK material embedded pipe to fasten and connect the metal penetration piece and the flange of the PEEK material embedded pipe, and the PEEK material embedded pipe is supported on the outer side wall of the underwater special equipment through a support. According to the corrosion-resistant insulating cabin bottom embedded pipeline system of the underwater special equipment, the problem that a traditional carbon steel sea-dredging embedded pipeline is poor in seawater erosion corrosion resistance is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of corrosion control for pipeline systems of underwater special equipment, and particularly to a corrosion-resistant and insulated bottom-mounted pre-buried pipeline system for underwater special equipment and an installation method thereof. Background Art

[0002] The bottom-mounted pre-buried pipe is one of the key parts of the seawater pipeline system of the ship auxiliary system. In the early stage of service, 20# steel was mostly used for the pre-buried pipes of surface and underwater equipment. Since the internal medium of the bottom-mounted pre-buried pipe is seawater and the outside is soaked by the bottom bilge water and sewage, the working conditions are very harsh. In addition, the pipeline needs to pass through different cabins and is connected to the hull and pipelines. There are many contacts between dissimilar metals, which are likely to cause galvanic corrosion and the leakage risk is relatively high. In addition, it is found in engineering applications that the space where the bottom-mounted pre-buried pipe is located is narrow, the construction conditions are limited, and the replacement is difficult. During the maintenance process, it is required to avoid replacement as much as possible. Traditional metal pre-buried pipes generally require the same service life as the equipment repair period. In recent years, in the bottom-mounted pre-buried pipe systems of the in-service underwater special equipment, problems such as serious corrosion failure of the through-cabin pipes of the bottom sewage tank and corrosion perforation of the bottom-mounted pre-buried pipes of the battery compartment of a certain equipment before reaching the mid-term repair period of service have successively occurred, seriously affecting the reliability of the bottom-mounted pre-buried pipes and the safety of the equipment: After inspecting the actual corrosion state of the bottom-mounted pre-buried pipes of the equipment, it is found that the main areas where corrosion perforation occurs are the local part on the inner side of the single-sided flange after the through-cabin wall pre-buried pipe passes through the cabin wall sleeve and the straight pipe section area laid on the battery bottom.

[0003] After detailed analysis, the main reasons for corrosion are as follows: First, after the steel pre-buried pipe passing through the cabin wall passes through the cabin wall sleeve and then is connected to the copper pipeline butterfly valve through a single-sided flange, due to reasons such as seawater erosion of the pipeline and great difficulty in process control, an obvious galvanic corrosion circuit is formed between the copper butterfly valve and the steel pre-buried pipe, and leakage or perforation occurs after long-term use; Another reason is that the 20 steel used for the straight pipe section of the pre-buried pipe on the actual ship may have local minor defects due to reasons such as process stability of the pipeline metallographic structure because the pipeline is relatively long (8-10m). After being soaked in seawater for a long time, pitting corrosion may occur, further causing corrosion perforation or leakage problems in the straight pipe section. Summary of the Invention

[0004] The main purpose of the present invention is to provide a corrosion-resistant and insulated bottom-mounted pre-buried pipeline system for underwater special equipment and an installation method thereof, aiming to solve the problem of poor seawater erosion resistance of traditional carbon steel seawater-connected pre-buried pipelines.

[0005] To achieve the above object, the present invention provides a corrosion-resistant and insulated bottom-mounted pre-buried pipeline system for underwater special equipment, including a metal through-cabin part, a PEEK material pre-buried pipe, a sealing gasket, and fasteners. Among them, The metal through-hull part is passed through the bulkhead and welded to it. A flange is provided at one end of the metal through-hull part located outside the bulkhead. The end of the PEEK material embedded pipe facing the metal through-hull part is a flange. A sealing gasket is provided between the flange of the metal through-hull part and the flange of the PEEK material embedded pipe. The fastener passes through the flanges of the metal through-hull part and the PEEK material embedded pipe to fasten and connect the two. The PEEK material embedded pipe is supported on the outer wall of the underwater special equipment by a bracket.

[0006] Preferably, the connecting section, straight pipe section, and elbow section of the PEEK material embedded pipe for connecting with the metal through-hull part. The straight pipe section is supported by a bracket, and the bracket is fixedly connected to the outer wall of the underwater special equipment. The connecting section, straight pipe section, and elbow section are all made of polyether ether ketone.

[0007] Preferably, the connecting section, elbow section, and straight pipe section are connected by fusion welding.

[0008] Preferably, the bracket is fixed to the outer wall of the underwater special equipment by double-sided welding.

[0009] Preferably, the sealing gasket is made of aramid rubber.

[0010] Preferably, the metal through-hull part is fixedly connected to the bulkhead by single-sided welding.

[0011] Preferably, the wall thickness of the PEEK material embedded pipe is calculated according to the following formula: , , where, is the pipeline negative deviation correction coefficient; is the design pressure, in MPa; is the pipeline outer diameter, in mm; is the allowable stress of the pipeline, in N / mm 2 ; is the welding efficiency coefficient; is the additional allowance for bending, in mm; is the bending radius, in mm.

[0012] Preferably, the pipeline negative deviation correction coefficient is calculated using the following formula: , where, is the percentage of the pipeline manufacturing negative deviation to the nominal wall thickness of the pipeline.

[0013] Preferably, the outer diameter / wall thickness ratio SDR of the PEEK material embedded pipe is 8 - 10.

[0014] The present invention further provides an installation method for the corrosion-resistant and insulated bottom embedded pipeline system of the underwater special equipment based on the above, including the following steps: Pass the metal through-hull fitting through the bulkhead or the sleeve on the bulkhead, and fixedly connect the metal through-hull fitting to the bulkhead or the sleeve on the bulkhead by welding. Align the flange of the metal through-hull fitting with the flange of the connecting section of the PEEK material embedded pipe, install a sealing gasket between the two flanges, and pass fasteners through the flanges to tightly connect the metal through-hull fitting and the connecting section of the PEEK material embedded pipe. Adopt the method of fusion welding to sequentially connect the elbow section and the straight pipe section on one side of the connecting section. A bracket is sleeved on the straight pipe section, and the bottom of the bracket is fixedly connected to the outer side wall of the underwater special equipment.

[0015] The corrosion-resistant and insulated bottom embedded pipeline system of the underwater special equipment proposed by the present invention has the following beneficial effects: 1. Since the embedded pipe of the existing material is replaced with PEEK material, the problem that the corrosion resistance of the traditional metal embedded pipe is difficult to meet the requirement of the same service life in actual ship repair is solved. 2. The through-hull fitting made of metal material and the embedded pipe made of PEEK material are adopted. Therefore, there is no galvanic corrosion defect caused by the joint connection of metal pipelines in the prior art, and the galvanic corrosion circuit is blocked. 3. The PEEK material is used to replace the traditional metal material, giving play to its high electrical insulation, mature welding process, high pressure resistance, high impact resistance, light weight, and excellent mechanical properties, meeting the engineering application of underwater special equipment. 4. The metal embedded pipeline which is integrally formed in the prior art is divided into two parts, namely the through-hull fitting and the PEEK material embedded pipe. The through-hull fitting is connected to the bulkhead. Since the through-hull fitting does not use PEEK material but steel material, it absorbs the advantages of the reliable connection between the traditional metal embedded pipe and the bulkhead, thus solving the problem that the PEEK underwater embedded pipe cannot be hermetically connected to the metal bulkhead. The underwater embedded pipeline can be connected to the bulkhead by using the present through-hull fitting, and at the same time, the pressure resistance and sealing performance can be satisfied. 5. The through-hull fitting and the PEEK material embedded pipe are connected by flanges and are equipped with a sealing gasket. The connection structure is simple and the sealing performance is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the corrosion-resistant and insulated bottom embedded pipeline system of the underwater special equipment of the present invention.

[0017] In the figure, 1 is a metal through-hull fitting, 2 is the flange of the PEEK material embedded pipe, 3 is the bulkhead, 4 is the sealing gasket, 5 is the PEEK material embedded pipe, 6 is the welding joint, 7 is the bracket, 8 is the fastener, and 9 is the straight pipe section.

[0018] The realization, functional features, and advantages of the purpose of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0019] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] It should be noted that in the description of the present invention, the orientation or positional relationship indicated by the terms "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0021] The present invention provides a corrosion-resistant and insulating bottom-embedded pipeline system for underwater special equipment.

[0022] Refer to Figure 1 , in this preferred embodiment, a corrosion-resistant and insulating bottom-embedded pipeline system for underwater special equipment includes a metal through-hull fitting 1, a PEEK material embedded pipe 5, a sealing gasket 4, and a fastener 8. Among them, The metal through-hull fitting 1 passes through the bulkhead 3 and is welded to it. A flange is provided at one end of the metal through-hull fitting 1 located outside the bulkhead 3. One end of the PEEK material embedded pipe 5 facing the metal through-hull fitting 1 is a flange. A sealing gasket 4 is provided between the flange of the metal through-hull fitting 1 and the flange of the PEEK material embedded pipe 5. The fastener 8 (the fastener 8 includes a bolt and a nut. The bolt and the nut are standard metal fasteners 8 adapted to the flange) passes through the flange of the metal through-hull fitting 1 and the flange of the PEEK material embedded pipe 5 to fasten and connect the two. The PEEK material embedded pipe 5 is supported on the outer wall of the underwater special equipment by a bracket 7.

[0023] When selecting the sealing gasket 4, its technical indicators and performance requirements shall comply with the provisions of GB / T 17727-1999. The bracket 7 is selected from hull steel or viscoelastic materials according to the design requirements of the pipeline system.

[0024] Specifically, in this embodiment, the PEEK material embedded pipe 5 is used for the connecting section connected to the metal through-chamber component 1, the straight pipe section 9, and the curved pipe section connecting the connecting section and the straight pipe section 9. The straight pipe section 9 is supported by a bracket 7, and the bracket 7 is fixedly connected to the outer wall of the underwater special equipment. The connecting section, the straight pipe section 9, and the curved pipe section are all made of polyetheretherketone.

[0025] Main parameters of PEEK materials: service life in seawater fluid environment is not less than 25 years; volume insulation resistivity is 10 15 -10 16 Ω·cm, which is 10 of the current dry insulation resistance threshold (1kΩ) on board. 12-13 times; density 1.320g / cm 3 About 1 / 6 of steel; mechanical properties: bending modulus up to 3600MPa, yield strength 110MPa, compressive strength greater than 100MPa, elastic modulus up to 4200Mpa; high wear resistance, friction coefficient not less than 0.15; water absorption rate (25℃*24h) not higher than 0.15%.

[0026] In this embodiment, the connecting section, the curved pipe section and the straight pipe section 9 are connected by melting welding, and the melting temperature is 300° C. to 400° C.

[0027] Specifically, the bracket 7 is fixed to the outer wall of the underwater special equipment by double-sided welding. The sealing gasket 4 is made of aramid rubber. The metal through-cabin component 1 is fixedly connected to the bulkhead 3 by single-sided welding.

[0028] In this embodiment, the optional nominal diameters of the PEEK material pre-buried pipe 5 are DN40, DN50, DN80, DN100, and DN150. The wall thickness specifications of the PEEK material pre-buried pipe 5 are 5mm, 6mm, 7mm, 8mm, 14mm and above, which meet the pressure and impact resistance requirements of the pre-buried pipe of underwater special equipment. When specifically selected, the wall thickness of the PEEK material pre-buried pipe 5 is 5mm, 6mm, 7mm, 8mm, 14mm and above. Calculated using the following formula: , (1) , (2) in, is the pipeline negative deviation correction coefficient; is the design pressure, in MPa; is the outer diameter of the pipeline, in mm; is the allowable stress of the pipeline, in N / mm 2 ; is the welding effectiveness coefficient; It is the additional allowance for bending, in mm; is the bending radius, in mm. Generally, 55 N / mm is selected. 2 The welding efficiency coefficient of PEEK material is 1.

[0029] Specifically, the pipeline negative deviation correction coefficient is calculated using the following formula: , (3) where is the percentage of the pipeline manufacturing negative deviation to the nominal wall thickness of the pipeline.

[0030] That is to say, the design of the PEEK material embedded pipe 5 pipeline should consider the formulas (1), (2), (3) and the requirements of the fifth group of specifications of GJB4000-2000, and be designed according to the following design criteria of the embedded pipeline system: a) The design pressure of the embedded pipeline is 3 MPa; b) The corrosion problem of dissimilar metals should be considered at the connection between the through-hull fitting and the steel bulkhead 3; c) Anticorrosion treatment should be carried out at the connection between the embedded pipeline and the steel side cup-type pipe joint and the through-hull fitting; d) The interface flange of the embedded pipeline meets the requirements of CB856-2004, and the electrical insulation design with the seawater pipeline should be considered; e) The manufacturing process should be simple, the manufacturing cost should also be low, and it should be able to meet the on-site installation; f) The service life of the embedded pipe should be considered the same as that of the ship.

[0031] In this embodiment, the outer diameter / wall thickness ratio SDR of the PEEK material embedded pipe 5 is 8-10. At this time, the anti-explosion pressure of the pipeline can reach 40-50 MPa.

[0032] The underwater special equipment corrosion-resistant and insulated bilge embedded pipeline system proposed in this embodiment has the following beneficial effects: 1. Since the PEEK material is used to replace the embedded pipe of the existing material, the problem that the corrosion resistance of the traditional metal embedded pipe is difficult to meet the requirements of the same service life of the actual ship repair is solved; 2. The through-hull parts made of metal material and the embedded pipe made of PEEK material are used. Therefore, there is no galvanic corrosion defect caused by the joint connection of metal pipelines in the prior art, and the galvanic corrosion circuit is blocked; 3. The PEEK material is used to replace the traditional metal material, giving play to its high electrical insulation, mature welding process, high pressure resistance, high impact resistance, light weight, and excellent mechanical properties, meeting the engineering application of underwater special equipment; 4. The metal embedded pipeline that was integrated in the prior art is divided into two parts, namely the through-hull fitting and the PEEK material embedded pipe 5. The through-hull fitting is connected to the bulkhead 3. Since the through-hull fitting does not use PEEK material but steel material, it absorbs the advantages of the reliable connection between the traditional metal embedded pipe and the bulkhead 3, thus solving the problem that the PEEK underwater embedded pipe cannot be hermetically connected to the metal bulkhead 3. Using this through-hull fitting can realize the connection problem between the underwater embedded pipeline and the bulkhead 3, and at the same time can meet the pressure resistance and sealing performance; 5. The through-hull fitting and the PEEK material embedded pipe 5 are connected by flanges and are fitted with a sealing gasket 4 for installation. Their connection structure is simple and has good sealing performance.

[0033] The present invention also provides an installation method for the corrosion-resistant and insulated bottom-embedded pipeline system of an underwater special equipment.

[0034] In this preferred embodiment, an installation method for the corrosion-resistant and insulated bottom-embedded pipeline system of the underwater special equipment based on the above includes the following steps: Step S10: Pass the metal through-hull fitting 1 through the bulkhead 3 or the sleeve on the bulkhead 3, and fixedly connect the metal through-hull fitting 1 to the bulkhead 3 or the sleeve on the bulkhead 3 by welding. Step S20: Align the flange of the metal through-hull fitting 1 with the flange of the connecting section of the PEEK material embedded pipe 5, install a sealing gasket 4 between the two flanges, and pass the fastener 8 through the flanges to tightly connect the metal through-hull fitting 1 and the connecting section of the PEEK material embedded pipe 5. Step S30: Adopt the method of fusion welding to sequentially connect the elbow section and the straight pipe section 9 on one side of the connecting section. A bracket 7 is sleeved on the straight pipe section 9, and the bottom of the bracket 7 is fixedly connected to the outer side wall of the underwater special equipment.

[0035] The temperature of the fusion welding is 300°C to 400°C.

[0036] The installation method proposed in this embodiment solves the problems that in the existing traditional underwater special equipment, the carbon steel through-sea embedded pipeline has poor corrosion resistance to seawater scouring, and it is difficult to repair / replace the bottom-embedded pipeline in a narrow space after corrosion and leakage, by dividing the existing embedded pipeline into two parts, one part is the through-hull fitting made of steel and the other part is made of PEEK material. The PEEK material used in the corrosion-resistant and insulated bottom-embedded pipeline system of this underwater special equipment has characteristics such as high electrical insulation, mature welding process, high pressure resistance, high impact resistance, light weight, and excellent mechanical properties, which can greatly improve the service performance of the seawater embedded pipeline of the in-research and new special underwater equipment and make up for the weak link of the embedded pipeline in the anti-corrosion of the entire seawater pipeline system.

[0037] The above is only the preferred embodiment of the present invention, and it does not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. An anti-corrosion and insulating embedded pipeline system for the bottom of an underwater special equipment, characterized in that, It includes a metal through-hull fitting, a PEEK material embedded pipe, a sealing gasket, and fasteners. Among them, the metal through-hull fitting passes through the hull wall and is welded to it. A flange is provided at one end of the metal through-hull fitting located outside the hull wall. The end of the PEEK material embedded pipe facing the metal through-hull fitting is a flange. A sealing gasket is provided between the flange of the metal through-hull fitting and the flange of the PEEK material embedded pipe. The fasteners pass through the flanges of the metal through-hull fitting and the PEEK material embedded pipe to fasten and connect the two. The PEEK material embedded pipe is supported on the outer wall of the underwater special equipment through a bracket.

2. The corrosion-resistant and insulating embedded pipeline system for the underwater special equipment as claimed in claim 1, wherein The PEEK material embedded pipe includes a connection section for connecting with the metal through-hull fitting, a straight pipe section, and a bent pipe section connecting the connection section and the straight pipe section. A bracket is supported on the straight pipe section, and the bracket is fixedly connected to the outer wall of the underwater special equipment. The connection section, the straight pipe section, and the bent pipe section are all made of polyether ether ketone.

3. The corrosion-resistant and insulating embedded pipeline system for the underwater special equipment bottom cabin according to claim 2, characterized in that, The connection section, the bent pipe section, and the straight pipe section are connected by fusion welding.

4. The corrosion-resistant and insulating bottom-embedded pipeline system for underwater special equipment according to claim 1, wherein The bracket is fixedly connected to the outer wall of the underwater special equipment by double-sided welding.

5. The corrosion-resistant and insulating embedded pipeline system for the underwater special equipment bottom of claim 1, characterized in that, The sealing gasket is made of aramid rubber.

6. The corrosion-resistant and insulating embedded pipeline system for the underwater special equipment as described in claim 1, wherein, The metal through-hull fitting is fixedly connected to the hull wall by single-sided welding.

7. The corrosion-resistant and insulating embedded pipeline system for the underwater special equipment as claimed in claim 1, wherein, The wall thickness of the PEEK embedded pipe Calculated using the following formula: ， ， Among them, is the pipeline negative deviation correction coefficient; is the design pressure, with the unit of MPa; is the outer diameter of the pipeline, with the unit of mm; is the allowable stress of the pipeline, with the unit of N / mm 2 ; is the effective welding coefficient; is the additional allowance for bending, with the unit of mm; is the bending radius, with the unit of mm.

8. The corrosion-resistant and insulating embedded pipeline system for the underwater special equipment bottom of the cabin according to claim 7, characterized in that, The pipeline negative deviation correction coefficient is calculated using the following formula: ， Among them, is the percentage of the negative deviation of pipeline manufacturing to the nominal wall thickness of the pipeline.

9. The corrosion-resistant and insulating embedded pipeline system for the underwater special equipment bilge according to any one of claims 1 to 8, characterized in that, The outer diameter / wall thickness ratio SDR of the PEEK material embedded pipe is 8 - 10.

10. An installation method for the corrosion-resistant and insulating bottom pre-buried pipeline system of the underwater special equipment according to any one of claims 1 to 9, characterized in that, It includes the following steps: Pass the metal through-hull fitting through the hull wall or the sleeve on the hull wall, and fixedly connect the metal through-hull fitting to the hull wall or the sleeve on the hull wall by welding; Align the flange of the metal through-hull fitting with the flange of the connection section of the PEEK material embedded pipe, install a sealing gasket between the two flanges, and pass the fasteners through the flanges to fasten and connect the metal through-hull fitting and the connection section of the PEEK material embedded pipe; Adopt the method of fusion welding to sequentially connect the bent pipe section and the straight pipe section on one side of the connection section. A bracket is sleeved on the straight pipe section, and the bottom of the bracket is fixedly connected to the outer wall of the underwater special equipment.

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