Reverse differential pressure self-tightening type deep water cable through-hull device and method

Abstract

The application discloses a reverse pressure difference self-tightening type deep water cable cabin-penetrating device for ships and a method thereof. The device comprises a sleeve, a first nut, a second nut, an inclined pressing gasket, a first rubber sealing ring, a second rubber sealing ring and a flat pressing gasket. The two sealing rings are radially contracted and tightly hold the cable by screwing the nuts. The end of the second rubber sealing ring is provided with an inwardly inclined sealing slope, which is matched with the pressing slope of the inclined pressing gasket. The application uses the water pressure in the sleeve to act on the sealing slope, drives the second rubber sealing ring to further radially expand, and realizes the reverse pressure difference self-tightening sealing, that is, the higher the water pressure, the tighter the sealing. The application first transplants the pressure difference self-tightening principle in the field of aerospace to the field of deep water cable cabin-penetrating devices for ships, and has the advantages of high sealing reliability, self-adapting self-tightening, reduced operation and maintenance cost and the like.

Description

Technical Field

[0001] This invention relates to the field of ship cable installation and high-pressure sealing technology. Specifically, it relates to a reverse pressure differential self-tightening marine deep-water cable passage device and method, and in particular to a high-reliability sealing technology that draws on the pressure differential self-tightening and double-ring redundant sealing principle of the airlock door of the space station and is applied to the passage of deep-water cables in ship cabins after mechanical reversal design. Background Technology

[0002] In shipbuilding, cables passing through the walls of deep-water tanks such as ballast tanks require rigorous sealing to prevent leakage by high-pressure water. Currently, the industry commonly uses a combination of blind flanges with machined internal threads and waterproof metal cable clamps for sealing. However, this solution has insufficient pressure resistance in deep, high-pressure conditions such as ballast tanks, making the sealing structure prone to leakage. This not only affects the stable operation of equipment but also leads to frequent maintenance, increasing operating costs and workload.

[0003] It is worth noting that in the aerospace field, the sealing technology of the space station airlock hatch employs advanced principles of "pressure differential self-tightening" and "dual-ring redundancy protection." Specifically, the space station utilizes the pressure difference between the atmospheric pressure inside the cabin and the vacuum environment outside, causing the hatch sealing rings to automatically tighten under the pressure difference, achieving an adaptive seal where the sealing effect strengthens as pressure increases. Simultaneously, the dual sealing rings provide redundant protection, ensuring that the other seal can still function reliably if one seal fails. This technology has already proven its extremely high reliability and long-term effectiveness in manned spaceflight programs.

[0004] However, the pressure differential self-tightening principle of space stations has never been applied to the field of deep-water cable penetration in ships. The main reason is that the sealing medium in space stations is gas (air), with the pressure differential pointing from high pressure inside the cabin to low pressure outside; while the sealing medium in deep-water ships is liquid (seawater), with the pressure differential pointing from high pressure outside the cabin to low pressure inside. The mechanical models, the direction of force on the sealing rings, and the failure modes are fundamentally different. Furthermore, space station hatches use a rigid-to-rigid sealing surface, while cable penetration involves a dynamic seal of an elastic body against a rigid body, making the sealing mechanism more complex. Therefore, how to adapt the highly reliable pressure differential self-tightening principle of space stations to the completely different technical field of deep-water cable penetration in ships has been a long-standing unsolved technical problem in this field. Summary of the Invention

[0005] This invention aims to provide a reverse pressure differential self-tightening marine deep-water cable penetration device and method to solve the problems of easy leakage and poor sealing reliability of existing cable penetration sealing devices in deep-water high-pressure environments. This invention, for the first time, creatively applies the pressure differential self-tightening and double-ring redundant sealing principle of space station airlock doors to the field of marine deep-water cable penetration through structural innovation and mechanical model reconstruction, achieving highly reliable and adaptive high-pressure sealing.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: (I) Product Structure Plan An innovative feature of a reverse differential pressure self-tightening marine deep-water cable insertion device includes: Sleeve, first nut, second nut, beveled clamping washer, first rubber sealing ring, second rubber sealing ring, and flat clamping washer; wherein, The sleeve is used to penetrate and fix to the water tank wall; The first rubber sealing ring and the second rubber sealing ring are sequentially arranged inside the sleeve along the axial direction; The flat-mouth compression washer is disposed on one axial side of the first rubber sealing ring; The beveled clamping washer is disposed on one axial side of the second rubber sealing ring; The first nut is threaded to one end of the sleeve and abuts against the flat-mouth compression washer; The second nut is threaded to the other end of the sleeve and abuts against the beveled clamping washer; The cable passes sequentially through the first nut, the flat-mouth compression washer, the first rubber sealing ring, the second rubber sealing ring, the beveled compression washer, and the second nut; When the first nut and the second nut are tightened, the flat-mouth compression washer axially compresses the first rubber sealing ring, and the oblique-mouth compression washer axially compresses the second rubber sealing ring, causing the first rubber sealing ring and the second rubber sealing ring to radially contract and grip the cable. The end of the second rubber sealing ring is provided with an inwardly inclined sealing slope, and the inclined clamping washer has a clamping slope that is adapted to the sealing slope; when the water pressure inside the sleeve increases, the water medium pressure acts on the sealing slope, driving the second rubber sealing ring to expand further radially, thereby achieving reverse self-tightening sealing.

[0007] Furthermore, the end of the second rubber sealing ring is inclined inward at an angle of 70 degrees.

[0008] Furthermore, a sealed cavity is formed between the first rubber sealing ring and the second rubber sealing ring. When water medium seeps into the sealed cavity, the resulting reverse water pressure acts on the inner side of the first rubber sealing ring to balance the external water pressure.

[0009] Furthermore, both the first and second rubber sealing rings are made of fluororubber.

[0010] Furthermore, the middle part of the sleeve is fixed to the water tank wall by welding.

[0011] Furthermore, both the first nut and the second nut are made of brass.

[0012] Furthermore, the sleeve, the flat-mouth clamping washer, and the beveled-mouth clamping washer are all made of steel.

[0013] (II) Methodology This invention also provides a reverse pressure differential self-tightening marine deep-water cable penetration sealing method based on the above-mentioned device, the innovation of which includes the following steps: S1: Conventional sealing step, in which the first rubber sealing ring undertakes the main sealing function, preventing water medium from penetrating into the sleeve; S2: High-pressure secondary sealing step. When the external water pressure increases and breaks through the first rubber sealing ring, the water medium seeps into the cavity of the sleeve. The second rubber sealing ring activates the secondary sealing function to bear the infiltrated water pressure load. S3: Reverse self-tightening sealing step. When the water pressure further increases and exceeds the initial sealing threshold of the second rubber sealing ring, the water medium enters the special cavity at the end of the second rubber sealing ring. The water pressure in the cavity applies an oblique force to the inclined end face of the second rubber sealing ring, forming a reverse pressure effect. As the water pressure in the cavity increases, the oblique force increases synchronously, causing the second rubber sealing ring to fit more tightly with the cable, realizing a reverse pressure differential self-tightening seal where the higher the water pressure, the tighter the seal.

[0014] Compared with the prior art, the reverse pressure differential self-tightening marine deep-water cable insertion device and method of the present invention have the following significant advantages and beneficial effects: 1. Creatively applying the self-tightening principle of space station pressure differential to the field of deep-water sealing in ships. This invention reveals for the first time the fundamental physical similarity between the "pressure differential self-tightening" principle of space station airlocks and the sealing of deep-water cables penetrating ship compartments—both utilize pressure differentials to drive the sealing rings to self-adaptively tighten. Although the sealing medium in space stations is gas and in ships it is liquid, and the pressure differential directions are opposite, this invention, through a unique inclined sealing surface and reverse pressure-bearing cavity design, successfully transforms the "positive pressure differential self-tightening" of space stations into "reverse pressure differential self-tightening" in a ship environment, achieving cross-domain technology transfer and reinvention. This is not merely a simple structural improvement, but a creative reconstruction of the sealing principle under different physical media and different pressure directions.

[0015] 2. Achieve a reverse pressure differential self-tightening sealing effect where the higher the water pressure, the tighter the seal. This invention innovatively designs a mating structure between a slanted compression washer and a tilted rubber sealing ring. When water pressure breaks through the double sealing rings and seeps into the dedicated cavity, the water pressure inside the cavity applies a slanted force to the tilted end face of the rubber sealing ring. The greater the water pressure, the stronger the reverse compression force, making the seal ring and cable fit increasingly tightly, forming an adaptive self-tightening seal. This is entirely consistent with the principle of a space station hatch tightening due to pressure difference in the vacuum environment of space, but it achieves a mechanical reversal from "pressure pushing outwards from inside the cabin" to "pressure squeezing inwards from outside the cabin." This effect is significantly superior to traditional passive sealing methods, structurally eliminating the risk of high-pressure leakage.

[0016] 3. Dual-ring redundant protection and pressure balancing mechanism significantly improve sealing reliability. This invention employs a multi-stage sealing structure with dual rubber sealing rings, drawing inspiration from the redundancy design of dual sealing rings used in space stations. The first sealing ring performs the basic sealing task under normal operating conditions, while the second sealing ring serves as a backup sealing line under high-pressure conditions, forming double protection. More importantly, the sealed cavity between the two sealing rings can form a water pressure differential balance protection mechanism: when a small amount of water seeps into this cavity, the internal water pressure acts in the opposite direction on the first sealing ring, offsetting some of the excessive pressure exerted on it by the external water pressure, allowing the first sealing ring to recover from an overpressure state to its own pressure-bearing limit. This mechanism effectively solves the industry problem of accelerated aging and failure of sealing rings due to unilateral overpressure under deep-water and high-pressure conditions.

[0017] 4. Reduce operation and maintenance costs and improve equipment service stability Traditional metal cable waterproof clamps require frequent maintenance due to insufficient sealing performance, increasing labor and time costs. The multi-stage sealing and self-tightening structure of this invention provides long-lasting and stable sealing capabilities, significantly reducing maintenance frequency and intensity, while simultaneously improving the overall service life and operational stability of the cable penetration sealing system.

[0018] 5. Compact structure and strong adaptability The components of this invention have a high degree of integration and a simple assembly process. The sleeve can be directly welded to the water tank wall to complete the installation without the need for additional complex auxiliary structures. It can be well adapted to the installation scenario where the cable passes through the ballast water tank wall and enters the pipe tunnel area, and has strong engineering practicality and promotion value. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 An enlarged diagram of A in the diagram.

[0020] Explanation of reference numerals in the attached figures: 1-Sleeve; 2-1-First nut; 2-2-Second nut; 3-Beveled clamping washer; 4-Second rubber sealing ring; 5-First rubber sealing ring; 6-Flat clamping washer; 7-Cable. Detailed Implementation

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0023] Example Please refer to Figure 1 and Figure 2 This invention provides a reverse pressure differential self-tightening marine deep-water cable penetration device, mainly used for sealing cables penetrating deep-water environments such as ballast tanks on ships. The design inspiration for this invention comes from the pressure differential self-tightening and double-ring redundant sealing principle of the airlock doors of space stations, and through creative structural modifications, it is made suitable for the high-pressure environment of deep-water ships.

[0024] The device mainly includes: sleeve 1, first nut 2-1, second nut 2-2, beveled clamping washer 3, second rubber sealing ring 4, first rubber sealing ring 5, and flat clamping washer 6. All components are concentrically assembled.

[0025] I. Structure and Assembly Relationship The sleeve 1 penetrates the water tank wall, and its outer wall is welded and fixed to the water tank wall at the middle position to form a stable integrated structure.

[0026] Cable 7 is threaded sequentially through the central axis into the first nut 2-1, the flat-mouth compression washer 6, the first rubber sealing ring 5, the second rubber sealing ring 4, the beveled compression washer 3, and the second nut 2-2. The first nut 2-1 and the second nut 2-2 respectively engage with the inner threads of the sleeve 1 at both ends and are screwed into the sleeve 1.

[0027] Specifically, during the tightening process, the first nut 2-1 located on one side (inside the water tank) compresses the flat-mouth compression washer 6, which in turn compresses the first rubber sealing ring 5 into the sleeve 1. Under axial pressure, the first rubber sealing ring 5 contracts radially, tightly covering the outer wall of the cable 7, thus achieving the first radial seal.

[0028] Simultaneously, during the tightening process, the second nut 2-2 located on the other side (outside the water tank) compresses the beveled clamping washer 3, which in turn compresses the second rubber sealing ring 4 into the sleeve 1. Under axial pressure, the inner diameter of the second rubber sealing ring 4 shrinks and tightly adheres to the outer wall of the cable 7, achieving a second radial seal.

[0029] II. Working Principle – Reverse sealing based on the pressure differential self-tightening principle The core technical principle of this invention is highly consistent with the sealing principle of the airlock hatch of a space station, but it achieves a creative reversal in its mechanical model:

[0030] This invention achieves the successful application of the space station's pressure differential self-tightening principle to the field of deep-water sealing in ships through the following innovative design: 1. Standard sealing stage (dual-ring redundant protection) Under normal operating conditions, the first rubber sealing ring 5 plays a major sealing role, preventing water from seeping into the sleeve 1. This stage embodies the first layer of protection concept of the space station's "dual-ring redundancy".

[0031] 2. High-pressure secondary sealing stage (redundant start-up) When the external water pressure increases and exceeds the sealing limit of the first rubber sealing ring 5, a small amount of water seeps into the cavity of the sleeve 1. At this time, the second rubber sealing ring 4 activates its secondary sealing function to absorb the pressure load of the seeping water. This is completely consistent with the redundancy design concept of the second sealing connection after the failure of the first seal on the space station.

[0032] Simultaneously, a pressure difference is formed on both sides of the first rubber sealing ring 5 (the water tank side and the sleeve cavity side). As the amount of infiltrated water increases, the pressure difference gradually decreases. This mechanism allows the first rubber sealing ring 5 to gradually recover from an overpressured state, similar to the pressure balance design between the two sealing rings on the space station.

[0033] 3. Reverse self-tightening sealing stage (differential pressure self-tightening core) If the water pressure increases further, the water accumulation in the cavity of sleeve 1 will continue to increase. When the water pressure exceeds the initial sealing threshold of the second rubber sealing ring 4, the water medium will enter the special cavity at the end of the second rubber sealing ring 4. The end of the second rubber sealing ring 4 in this cavity is inclined inward at an angle of about 70 degrees, and its outer side is pressed and positioned by the beveled pressure washer 3 at a suitable angle.

[0034] This structure is fundamentally identical in principle to the "pressure differential self-tightening inclined surface" of the space station hatch seal: when the medium pressure acts on the inclined sealing surface, the pressure is decomposed into a positive clamping component perpendicular to the sealing surface. In the space station, the cabin gas pressure pushes the seal outward, making it fit tightly against the hatch frame; in this invention, the seawater pressure seeping into the cavity applies an upward force to the inclined end face of the second rubber seal 4, creating a "reverse pressure" effect (see...). Figure 2 When the water pressure exceeds the limit, it seeps into the rubber sealing ring 4. The direction of the force exerted by the water in the pressure-bearing cavity on the inner inclined rubber ring is as follows.

[0035] As the water pressure inside the cavity continuously increases, the oblique force increases synchronously, causing the second rubber sealing ring 4 to adhere more tightly to the cable 7—this is a creative replication of the core mechanism of "the higher the pressure, the tighter the seal" in space stations in deep-water sealing of marine vessels. The only difference is that space stations use "positive pressure differential self-tightening" (from the inside out), while this invention uses "reverse pressure differential self-tightening" (from the outside in), but the physical essence of both—using the pressure of the working medium itself to drive the sealing ring to self-adaptively tighten—is exactly the same.

[0036] 4. Water pressure differential balance protection mechanism (enhanced originality) Furthermore, the sealed cavity between the first rubber sealing ring 5 and the second rubber sealing ring 4 also has a water pressure differential balance protection function: when a small amount of water seeps into this cavity, the internal water pressure acts in the opposite direction on the first rubber sealing ring 5, offsetting part of the excessive pressure exerted on it by the external water pressure, allowing the first rubber sealing ring 5 to return from an overpressure state to its own pressure-bearing limit range. This mechanism is not reflected in space station technology and is an original improvement in this field for water-sealing conditions, further enhancing sealing reliability.

[0037] III. Materials and Parameters In this embodiment: Both the first rubber sealing ring 5 and the second rubber sealing ring 4 are made of fluororubber (compliant with HG / T 2809-2019 standard), which has excellent resistance to seawater and high pressure. The elastic modulus and compression set of fluororubber have been optimized, enabling it to withstand repeated pressure fluctuations over a long period without failure.

[0038] The flat-mouth clamping washer 6 and the beveled-mouth clamping washer 3 are made of steel (compliant with GB / T 700-2006 standard).

[0039] Sleeve 1 is made of steel (compliant with GB / T 699-1999 standard).

[0040] The first nut 2-1 and the second nut 2-2 are made of brass (compliant with GB / T 5231-2021 standard) and have good resistance to seawater corrosion.

[0041] The device can be adapted to different specifications and sizes according to the cable diameter. Specific parameters can be found in the table below (see example table for some specifications). Figure 1 ):

[0042] IV. Installation Method During installation, insert sleeve 1 through the pre-drilled hole in the water tank wall and adjust it to the center position so that the side of sleeve 1 is welded and fixed to the water tank wall. After cooling, install each component in sequence according to the aforementioned assembly relationship, and finally tighten the first nut 2-1 and the second nut 2-2 at both ends to the specified torque using a wrench.

[0043] V. Sealing Method and Procedure Based on the above-described device, the reverse pressure differential self-tightening sealing method provided by the present invention includes the following steps: Step S1 (Conventional sealing): The first rubber sealing ring 5 plays a major sealing role, preventing water medium from penetrating into the sleeve 1.

[0044] Step S2 (High-pressure secondary sealing): When the external water pressure increases and breaks through the first rubber sealing ring 5, the water medium seeps into the cavity of the sleeve 1, and the second rubber sealing ring 4 activates the secondary sealing function to bear the infiltrated water pressure load.

[0045] Step S3 (Reverse Self-Tightening Seal): When the water pressure further increases and exceeds the initial sealing threshold of the second rubber sealing ring 4, the water medium enters the special cavity at the end of the second rubber sealing ring 4. The water pressure in the cavity applies an oblique force to the inclined end face of the second rubber sealing ring 4, forming a reverse pressure effect. As the water pressure in the cavity increases, the oblique force increases synchronously, causing the second rubber sealing ring 4 to fit more tightly with the cable 7, achieving a reverse pressure differential self-tightening seal where the higher the water pressure, the tighter the seal.

[0046] VI. Verification of Technical Effects The device of this invention underwent simulated deep-water high-pressure environment testing (operating pressure 20-30 bar, corresponding to a water depth of approximately 200-300 meters) and showed no visible leakage after 1000 hours of continuous operation. Compared to the traditional blind flange + metal cable waterproof clamp joint solution, the sealing life of this invention is increased by approximately 5 times, and the maintenance cycle is extended to more than 3 times that of the original solution. In the ultimate pressure test (40 bar, corresponding to a water depth of approximately 400 meters), the reverse self-tightening structure of this invention can still maintain an effective seal, while the traditional solution begins to leak above 25 bar.

[0047] In summary, this invention successfully solves a long-standing technical challenge in sealing deep-water cables penetrating cargo compartments in ships by creatively adapting and reversing the pressure differential self-tightening and double-ring redundant sealing principle of space station airlocks. This invention not only achieves innovation at the product structure level but also provides a novel high-pressure sealing method based on the pressure differential self-tightening principle, demonstrating significant creativity, novelty, and practicality.

[0048] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A reverse pressure differential self-tightening marine deep-water cable insertion device, characterized in that, include: Sleeve (1), first nut (2-1), second nut (2-2), beveled clamping washer (3), first rubber sealing ring (5), second rubber sealing ring (4), and flat clamping washer (6); wherein, The sleeve (1) is used to penetrate and fix to the water tank wall; The first rubber sealing ring (5) and the second rubber sealing ring (4) are sequentially arranged inside the sleeve (1) along the axial direction; The flat-mouth compression washer (6) is disposed on one axial side of the first rubber sealing ring (5); The oblique clamping washer (3) is disposed on one axial side of the second rubber sealing ring (4); The first nut (2-1) is threaded to one end of the sleeve (1) and abuts against the flat-mouth compression washer (6). The second nut (2-2) is threaded to the other end of the sleeve (1) and abuts against the beveled clamping washer (3). The cable (7) passes through the first nut (2-1), the flat-mouth compression washer (6), the first rubber sealing ring (5), the second rubber sealing ring (4), the beveled compression washer (3), and the second nut (2-2) in sequence. When the first nut (2-1) and the second nut (2-2) are tightened, the flat-mouth compression washer (6) axially compresses the first rubber sealing ring (5), and the oblique-mouth compression washer (3) axially compresses the second rubber sealing ring (4), causing the first rubber sealing ring (5) and the second rubber sealing ring (4) to radially contract and hold the cable (7). The end of the second rubber sealing ring (4) is provided with an inwardly inclined sealing slope, and the inclined pressure washer (3) has a pressure slope that is adapted to the sealing slope; when the water pressure inside the sleeve (1) increases, the water medium pressure acts on the sealing slope, driving the second rubber sealing ring (4) to expand further radially, thereby achieving reverse self-tightening sealing.

2. The reverse pressure differential self-tightening marine deep-water cable insertion device according to claim 1, characterized in that: The end of the second rubber sealing ring (4) is inclined inward at an angle of 70 degrees.

3. The reverse pressure differential self-tightening marine deep-water cable insertion device according to claim 1, characterized in that: A sealed cavity is formed between the first rubber sealing ring (5) and the second rubber sealing ring (4). When water medium seeps into the sealed cavity, the resulting reverse water pressure acts on the inner side of the first rubber sealing ring (5) to balance the external water pressure.

4. The reverse pressure differential self-tightening marine deep-water cable insertion device according to claim 1, characterized in that: Both the first rubber sealing ring (5) and the second rubber sealing ring (4) are made of fluororubber.

5. The reverse pressure differential self-tightening marine deep-water cable insertion device according to claim 1, characterized in that: The middle part of the sleeve (1) is fixed to the water tank wall by welding.

6. The reverse pressure differential self-tightening marine deep-water cable insertion device according to claim 1, characterized in that: Both the first nut (2-1) and the second nut (2-2) are made of brass.

7. The reverse pressure differential self-tightening marine deep-water cable insertion device according to claim 1, characterized in that: The sleeve (1), the flat-mouth clamping washer (6) and the oblique-mouth clamping washer (3) are all made of steel.

8. A method for sealing a marine deep-water cable through a hull using a reverse pressure differential self-tightening device based on any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Conventional sealing steps, with the first rubber sealing ring (5) playing the main sealing role, preventing water medium from penetrating into the sleeve (1); S2: High-pressure secondary sealing step. When the external water pressure increases and breaks through the first rubber sealing ring (5), the water medium seeps into the cavity of the sleeve (1), and the second rubber sealing ring (4) starts the secondary sealing function to bear the infiltrated water pressure load. S3: Reverse self-tightening sealing step. When the water pressure further increases and exceeds the initial sealing threshold of the second rubber sealing ring (4), the water medium enters the special cavity at the end of the second rubber sealing ring (4). The water pressure in the cavity applies an oblique force to the inclined end face of the second rubber sealing ring (4), forming a reverse pressure effect. As the water pressure in the cavity increases, the oblique force increases synchronously, causing the second rubber sealing ring (4) to fit more tightly with the cable (7), realizing a reverse pressure differential self-tightening seal where the higher the water pressure, the tighter the seal.

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