A wiring device for deep well pumps inside a dual-fuel LNG main unit tank

Abstract

This utility model relates to the field of marine technology, and in particular to a wiring device for a deep well pump inside a dual-fuel LNG main engine tank. The wiring device includes pre-embedded pipes, supports, and pipe clamps. The pre-embedded pipes are entirely embedded inside the LNG tank. The supports are fixed to the outer wall of the pre-embedded pipes along their axial direction. The pipe clamps are mounted on the supports and have mounting holes for cables to pass through. On straight pre-embedded pipes, the mounting holes of the pipe clamps are coaxial, while on curved pre-embedded pipes, the mounting holes are located on the same concentric arc profile. This device uses pre-embedded pipes instead of supports directly mounted on the inner wall of the tank, avoiding localized stress concentration damage to the tank. The mounting holes isolate the cables from the tank and other components, preventing surge friction from causing wear on the cable sheath. The differentiated pipe clamp layout ensures smooth cable laying, reduces localized impact loads, and counteracts surge forces to prevent structural deformation. The combination of supports and pipe clamps replaces traditional adhesive bonding, solving the problem of cryogenic adhesive failure and improving cable fixation reliability.

Description

Technical Field

[0001] This utility model relates to the field of marine technology, and in particular to a wiring device for a deep well pump inside a dual-fuel LNG main engine tank. Background Technology

[0002] Against the backdrop of the global shipping industry actively responding to the call for green environmental protection and accelerating the process of energy conservation and emission reduction, dual-fuel main engines for ultra-large ships have been widely used in the industry due to their significant advantages of high efficiency and cleanliness. LNG (liquefied natural gas), as a clean and efficient energy source, has become one of the ideal choices for ship fuel, making the use of LNG tanks in ultra-large ships increasingly common. However, the method of fixing cables inside LNG tanks has become a thorny problem for shipyards.

[0003] The actual operating conditions of liquefied natural gas inside LNG tanks are extremely harsh, with temperatures as low as -163 degrees Celsius. The deep-well pumps inside the tanks are key equipment for the injection and removal of liquefied natural gas, and connecting them with cables is an essential step in ensuring the normal operation of the LNG tanks. However, in such a low-temperature environment, how to safely and reliably secure the cables has become a pressing technical challenge that needs to be overcome.

[0004] Currently, there are two main methods for fixing LNG containers: one is to directly weld flat iron to the tank body and then secure it with stainless steel cable ties; the other is to use epoxy adhesive bonding brackets. However, both methods have significant drawbacks. From the perspective of tank structural safety, directly welding flat iron to the tank body violates pressure vessel safety regulations. The welding process not only alters the local metal microstructure of the tank, leading to stress concentration and reducing the tank's strength and service life, but also may compromise the tank's sealing performance due to welding quality issues, posing a serious safety hazard to LNG storage. While epoxy adhesive bonding brackets avoid direct damage to the tank body from welding, the epoxy bonding process requires extremely high standards for the tank's surface treatment. Improper surface treatment, such as the presence of oil or impurities, will significantly affect the bonding effect. Furthermore, during long-term use, the adhesive layer may gradually fail due to external factors, also causing irreversible damage to the tank body.

[0005] From the perspective of cable fixation stability and durability, in practical applications, the forces generated by ultra-low temperatures and liquefied natural gas surges will impact the cable fixation. Under this impact, high-frequency friction will occur between the cable and the stainless steel binding tape. Furthermore, the ultra-low temperature environment of -163℃ will cause the cable outer sheath to become brittle, further increasing the risk of outer sheath breakage. The ultra-low temperature environment will also significantly reduce the adhesion strength of the epoxy adhesive layer. Utility Model Content

[0006] To address the technical problems of existing deep well pump cable fixing methods in LNG tanks, which are prone to causing stress concentration in the tank, cable sheath rupture, and bonding failure under ultra-low temperature and liquefied natural gas surge environments, this utility model provides a wiring device for deep well pumps in dual-fuel LNG tanks.

[0007] Therefore, the present invention provides the following technical solution: A wiring device for a deep well pump inside a dual-fuel LNG tank includes a pre-embedded pipeline, a support, and pipe clamps. The pre-embedded pipeline is entirely embedded inside the LNG tank. The support is fixedly installed on the outer wall of the pre-embedded pipeline along its axial direction. The pipe clamps are installed on the support, and each pipe clamp has an installation hole for a cable to pass through. For a straight section of the pre-embedded pipeline, the axis of the installation holes of all the pipe clamps is located on the same straight line. For a curved section of the pre-embedded pipeline, the axis of the installation holes of all the pipe clamps is located on a concentric arc profile corresponding to the same center.

[0008] Furthermore, the pipe clamp includes a first body and a second body, with the first body mounted on a bracket; both the first body and the second body are rectangular structures, and arc-shaped grooves are respectively opened on the end faces of the first body and the second body that fit together; the first body and the second body are detachably connected by bolts, and the corresponding arc-shaped grooves on their end faces together form an installation hole for the cable to pass through.

[0009] Furthermore, the bracket includes a support rod and a mounting plate. The support rod is installed perpendicular to the axial direction of the pre-embedded pipeline on the outer wall of the pre-embedded pipeline. The mounting plate is installed at the end of the support rod, and the first body is installed on the mounting plate.

[0010] Furthermore, the bolt passes through the second body, the first body, and the mounting plate in sequence, and a nut is threaded onto the exposed end of the bolt; between the nut and the mounting plate, and at a position sleeved on the outer periphery of the bolt, a flat washer is fitted on the side near the mounting plate, and a spring washer is fitted on the side near the nut.

[0011] Furthermore, the first and second bodies are made of PTFE, and the bolts are made of stainless steel; corrugated buffer sections are provided on the outer walls of both the first and second bodies.

[0012] Furthermore, the inner walls of the arc-shaped grooves of the first and second bodies are provided with micropores.

[0013] Furthermore, the material of the pre-embedded pipeline is DN50 stainless steel; a nano-aerogel gasket is installed between the contact surface between the pre-embedded pipeline and the inner wall of the LNG tank; and there is an insulation gap between the pipe clamp and the inner wall of the LNG tank.

[0014] Advantages and positive effects of this utility model: By pre-embedding the pipelines entirely within the LNG tank, instead of the traditional method of "directly installing the brackets on the inner wall of the tank," damage to the inner wall of the tank due to localized stress concentration is avoided.

[0015] The mounting holes on the pipe clamps provide a dedicated and stable channel for the cables, effectively isolating the cables from direct contact with the tank and other components. This prevents wear on the cable sheath caused by friction during liquefied natural gas surges, thus extending the cable's service life.

[0016] For the straight and curved sections of the pre-buried conduit, a differentiated pipe clamp layout design is adopted. In straight sections, the installation hole axes of all pipe clamps are aligned on the same straight line; in curved sections, the installation hole axes are located on concentric arc profiles corresponding to the same center. This design makes cable laying smoother, avoids forced bending, and ensures that the force exerted on the pipe clamps by the cable is evenly distributed along different paths, significantly reducing local impact loads. Even in the event of surge impact, the pre-buried conduit and support structure work together to offset external forces, preventing structural deformation or loosening and avoiding cracking of the cable sheath.

[0017] The combination of brackets and pipe clamps completely replaces the traditional adhesive fixing process, fundamentally solving the problem of adhesive failure in ultra-low temperature environments, significantly improving the long-term reliability of cable fixing, and ensuring the continuous and stable operation of the wiring structure in extreme environments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This utility model provides a schematic diagram of the installation structure of a deep well pump wiring device inside a dual-fuel LNG tank.

[0020] Figure 2 This utility model provides a pipe clamp structure diagram for a deep well pump wiring device inside a dual-fuel LNG tank.

[0021] Figure 3 This utility model provides a structural diagram of a support structure for a deep well pump wiring device inside a dual-fuel LNG tank.

[0022] In the diagram: 1. Embedded pipe; 2. Bracket; 3. Pipe clamp; 4. First body; 5. Flat washer; 6. Spring washer; 7. Nut; 8. Mounting hole; 9. Second body; 10. Arc groove; 11. Bolt; 12. Support rod; 13. Mounting plate. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0024] This utility model provides a wiring device for a deep well pump inside a dual-fuel LNG tank, such as... Figure 1 As shown, the system includes a pre-embedded pipeline 1, a support 2, and a pipe clamp 3. The pre-embedded pipeline 1 is entirely pre-embedded inside the LNG tank. The material of the pre-embedded pipeline 1 is DN50 stainless steel. A nano-aerogel gasket is installed between the pre-embedded pipeline 1 and the inner wall of the LNG tank. The support 2 is fixedly installed on the outer wall of the pre-embedded pipeline 1 along the axial direction. The pipe clamp 3 is installed on the support 2, and there is an insulation gap between the pipe clamp 3 and the inner wall of the LNG tank.

[0025] like Figure 2 As shown, the pipe clamp 3 has an installation hole 8 for the cable to pass through; for the same straight pre-embedded pipe 1, the axis of the installation hole 8 of all the pipe clamps 3 is located on the same straight line; for the same curved pre-embedded pipe 1, the axis of the installation hole 8 of all the pipe clamps 3 is located on the concentric arc profile corresponding to the same center.

[0026] The pipe clamp 3 includes a first body 4 and a second body 9. The first body 4 is mounted on the bracket 2. Both the first body 4 and the second body 9 are rectangular structures, and arc-shaped grooves 10 are respectively formed on the end faces of the first body 4 and the second body 9 that are in contact with each other. The inner walls of the arc-shaped grooves 10 of the first body 4 and the second body 9 are provided with micropores. The micropores are used to store lubricant to reduce friction between the cable and the pipe clamp 3.

[0027] The first body 4 and the second body 9 are detachably connected by bolts 11, and the corresponding arc-shaped grooves 10 on their end faces together form a mounting hole 8 for the cable to pass through. Figure 3As shown, the bracket 2 includes a support rod 12 and a mounting plate 13. The support rod 12 is installed perpendicular to the axial direction of the pre-embedded pipe 1 on the outer wall of the pre-embedded pipe 1. The mounting plate 13 is installed at the end of the support rod 12, and the first body 4 is installed on the mounting plate 13. By selecting support rods 12 of different lengths, the position of the pipe clamp 3 can be adjusted. The bolt 11 passes through the second body 9, the first body 4, and the mounting plate 13 in sequence. The exposed end of the bolt 11 is threaded with a nut 7. The nut 7 is fitted between the mounting plate 13 and the outer periphery of the bolt 11. A flat washer 5 is fitted on the side near the mounting plate 13, and a spring washer 6 is fitted on the side near the nut 7. The first body 4 and the second body 9 are made of PTFE, and the bolt 11 is made of stainless steel. Corrugated buffer sections are provided on the outer walls of both the first body 4 and the second body 9.

[0028] Working Principle: The pre-embedded pipeline 1, made of DN50 stainless steel, is entirely embedded within the LNG tank, serving as the installation base for the support 2 and pipe clamps 3. This avoids stress concentration caused by directly fixing the support to the inner wall of the tank. The nano-aerogel gasket (3mm thick, thermal conductivity 0.018W / m•K) between its contact surface and the inner wall of the tank breaks up cold bridges, reducing heat transfer between the tank and the pipeline, while also buffering potential shrinkage displacement due to material differences. The stainless steel material possesses excellent low-temperature rigidity, which, combined with the elastic buffering of the nano-aerogel gasket, resists shrinkage deformation at ultra-low temperatures, ensuring pipeline stability and providing a fixed reference for the subsequent installation of the support and pipe clamps.

[0029] The bracket 2 consists of a support rod 12 and a mounting plate 13. The support rod 12 is axially fixed to the outer wall of the pre-embedded pipeline 1, perpendicular to it. The mounting plate 13 serves as the mounting carrier for the pipe clamp 3, stably supporting the pipe clamp 3 on the outside of the pre-embedded pipeline. By selecting support rods 12 of different lengths, the distance between the pipe clamp 3 and the pre-embedded pipeline can be flexibly adjusted to meet the laying requirements of cables of different specifications. The combined structure of the support rod 12 and the mounting plate 13 disperses the clamping force of the pipe clamp 3 on the cable to the pre-embedded pipeline 1, avoiding local overload, while ensuring the thermal insulation gap between the pipe clamp 3 and the inner wall of the LNG tank, further reducing cold conduction and stress on the inner wall of the LNG tank. The pipe clamp 3 consists of a first body 4 and a second body 9. The arc-shaped groove 10 on the mating end face of the two bodies forms an installation hole 8 for the cable to pass through, so as to achieve precise positioning of the cable. In addition, for the straight section and the curved section of the pre-buried pipe 1, the installation hole axis is designed to be on the same straight line and the installation hole axis is on the same circular arc contour, respectively, to ensure smooth cable laying and avoid damage to the protective sleeve caused by forced bending.

[0030] The micropores on the inner wall of the arc groove 10 can store lubricant (molybdenum disulfide nanoparticles, friction coefficient ≤0.03), reducing friction and wear between the cable and the inner wall of the pipe clamp. Especially in surge environments, it can prevent the protective sleeve from being scratched by cable swaying.

[0031] The first body 4 and the second body 9 are made of PTFE material (linear expansion coefficient 12×). / ℃, -196℃, elongation ≥200%), at -163℃, the expansion of PTFE can compensate for the shrinkage of the metal, thus reducing the fluctuation of the clamping force. 10%, to avoid clamping too loosely or too tightly at low temperatures. The corrugated buffer section on the outer wall of the body (compressible deformation amount) A dynamic unloading channel (10mm) is formed, which can deform during surge impact, converting the impact energy into elastic potential energy (absorption rate > 85%), thus offsetting the impact of external forces on the cable and structure. The two are connected by bolts 11 (stainless steel, preload controllable up to 50). The detachable connection (5 N•m) is achieved by bolts passing through the second body 9, the first body 4 and the mounting plate 13, and then using flat washers 5 (near the mounting plate) and spring washers 6 (near the nut 7) to prevent loosening and fix the connection, replacing traditional bonding and solving the problem of bonding failure at low temperatures.

[0032] The table below compares the performance of the wiring device of this application with that of traditional stainless steel cable ties: Comparison table of the performance of the wiring device in this application with traditional stainless steel cable ties

[0033] As can be seen from the table above, the performance indicators of the cabling device in this application significantly exceed those of traditional stainless steel cable ties.

[0034] Replacing cables inside an LNG tank requires completely purging the LNG from the tank before workers can enter to perform the work. This process is labor-intensive and costly, with each replacement costing approximately 16 million to 32 million RMB. Traditionally, cables need to be replaced after 3-4 filling and unloading cycles of LNG. However, the wiring device described in this application allows for 200 filling and unloading cycles without cable replacement, significantly reducing maintenance costs.

[0035] Conventional cable fixing methods inside LNG tanks involve welding flat iron to the inner wall of the tank and securing the cables with stainless steel cable ties, or using adhesive bonding. This utility model patent uses a combination of brackets and pipe clamps to replace the traditional adhesive bonding and stainless steel cable ties fixing methods. This solves the problems of adhesive bonding failure at ultra-low temperatures and the frictional breakage of the cable sheath and stainless steel cable ties caused by the force generated by liquefied natural gas surges. This improves the reliability of cable fixing and ensures stable operation of wiring in extreme environments. Compared with traditional cable fixing methods inside LNG tanks, this utility model patent has the advantage of low maintenance costs. Traditional methods require regular replacement of cable ties and epoxy adhesive brackets (requiring replacement every 1-2 years), while this patented cable type can achieve maintenance-free operation throughout its entire life cycle.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A wiring device for a deep well pump inside a dual-fuel LNG tank, characterized in that, The system includes a pre-embedded pipeline (1), a support (2), and pipe clamps (3). The pre-embedded pipeline (1) is pre-embedded in the LNG tank. The support (2) is fixedly installed on the outer wall of the pre-embedded pipeline (1) along the axial direction of the pre-embedded pipeline (1). The pipe clamps (3) are installed on the support (2), and the pipe clamps (3) are provided with mounting holes (8) for cables to pass through. For the same straight pre-embedded pipeline (1), the axis of the mounting holes (8) of all the pipe clamps (3) is located on the same straight line. For the same curved pre-embedded pipeline (1), the axis of the mounting holes (8) of all the pipe clamps (3) is located on the concentric arc profile corresponding to the same center.

2. The wiring device for a deep well pump inside a dual-fuel LNG tank according to claim 1, characterized in that, The pipe clamp (3) includes a first body (4) and a second body (9). The first body (4) is mounted on the bracket (2). Both the first body (4) and the second body (9) are rectangular structures, and arc-shaped grooves (10) are respectively opened on the end faces of the first body (4) and the second body (9) that fit together. The first body (4) and the second body (9) are detachably connected by bolts (11), and the corresponding arc-shaped grooves (10) on the end faces of the two together form an installation hole (8) for the cable to pass through.

3. The wiring device for a deep well pump inside a dual-fuel LNG tank according to claim 2, characterized in that, The bracket (2) includes a support rod (12) and a mounting plate (13). The support rod (12) is installed perpendicular to the axial direction of the pre-embedded pipeline (1) on the outer wall of the pre-embedded pipeline (1). The mounting plate (13) is installed at the end of the support rod (12), and the first body (4) is installed on the mounting plate (13).

4. A wiring device for a deep well pump inside a dual-fuel LNG tank according to claim 3, characterized in that, The bolt (11) passes through the second body (9), the first body (4) and the mounting plate (13) in sequence. The exposed end of the bolt (11) is threaded with a nut (7). The nut (7) is positioned between the nut (7) and the mounting plate (13) and on the outer periphery of the bolt (11). A flat washer (5) is fitted on the side near the mounting plate (13), and a spring washer (6) is fitted on the side near the nut (7).

5. A wiring device for a deep well pump inside a dual-fuel LNG tank according to claim 2, characterized in that, The first body (4) and the second body (9) are made of PTFE, and the bolt (11) is made of stainless steel; corrugated buffer sections are provided on the outer side walls of the first body (4) and the second body (9).

6. A wiring device for a deep well pump inside a dual-fuel LNG tank according to claim 2, characterized in that, The inner walls of the arc-shaped grooves (10) of the first body (4) and the second body (9) are provided with micropores.

7. A wiring device for a deep well pump inside a dual-fuel LNG tank according to claim 1, characterized in that, The embedded pipeline (1) is made of DN50 stainless steel; a nano aerogel gasket is installed between the embedded pipeline (1) and the inner wall of the LNG tank; there is an insulation gap between the pipe clamp (3) and the inner wall of the LNG tank.

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