Optical cable tail end sealing device

Abstract

The utility model discloses a tail end sealing device for an optical cable, and the device comprises an upper sealing clamping sleeve which sleeves and presses the outer wall of an inner-layer steel pipe of the optical cable; the sealing tool body is a hollow metal shell and is fixedly connected to the lower end of the upper sealing clamping sleeve; the lower sealing clamping sleeve is inserted into an outlet in the lower end of the sealing tool body and is sleeved and pressed on the outer wall of the inner-layer steel pipe; the sealing cylinder is arranged outside the lower sealing clamping sleeve in a sleeving manner and is fixedly connected to the external thread section of the sealing tool body through threads; the inner-layer steel pipe sequentially penetrates through the upper sealing clamping sleeve, the sealing tool body, the lower sealing clamping sleeve and the sealing cylinder. The upper sealing clamping sleeve and the lower sealing clamping sleeve are both of a high-pressure self-tightening structure, and a first seal and a second seal are formed respectively. A guide hole and a limiting shoulder are arranged in the sealing tool body and are used for centrally guiding and axially limiting an inner-layer steel pipe; the sealing cylinder and the sealing tool body are connected to form a closed sealing cavity.

Description

Technical Field

[0001] This utility model relates to the field of optical cable protection technology, and in particular to an optical cable tail sealing device. Background Technology

[0002] With the continuous increase in oil and gas extraction depth, higher requirements are placed on the stable operation of optical fiber cables in downhole environments. Currently, the optical fiber cable structure used in downhole monitoring systems typically consists of an outer metal sheath, an inner steel tube, and optical fibers. Optical fibers are extremely sensitive to moisture; once moisture seeps into the steel tube, irreversible "hydrogen loss" can occur, leading to severe signal attenuation, monitoring failure, and even the complete failure of the optical cable. Therefore, the sealing treatment of the cable end in the complex downhole environment has become a key technology for ensuring the long-term reliable operation of the system.

[0003] Existing tail-end sealing technologies mainly include two categories: waterproof tape wrapping and metal ferrule sealing. Waterproof tape sealing is simple in structure and suitable for surface or temporary applications, but it cannot withstand the high pressure and high humidity environment downhole. While ferrule sealing structures have a certain pressure resistance, they are usually single-stage seals. Once a section loosens or ages and fails, moisture can penetrate, leading to the risk of fiber optic exposure. Although existing patents such as CN105849823A propose threaded ferrule structures, they still lack redundant sealing design, making it difficult to meet the sealing reliability requirements of long-term high-pressure operations in oil and gas wells.

[0004] This invention provides a sealing device for the end of an optical cable that can effectively extend the life of the optical cable and prevent hydrogen loss. Utility Model Content

[0005] This utility model aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of this utility model is to provide an optical cable tail sealing device, which includes:

[0006] The upper sealing sleeve is fitted and pressed tightly against the outer wall of the inner steel tube of the optical cable;

[0007] The sealing tool body is a hollow metal shell, which is fixedly connected to the lower end of the upper sealing sleeve;

[0008] The lower sealing sleeve is inserted into the lower outlet of the sealing tool body, and is fitted and pressed against the outer wall of the inner steel pipe;

[0009] The sealing cylinder is fitted over the lower sealing sleeve and fixed to the external threaded section of the sealing tool body via a threaded connection.

[0010] The inner steel pipe is sequentially passed through the upper sealing sleeve, the sealing tool body, the lower sealing sleeve, and the sealing cylinder. Both the upper and lower sealing sleeves are high-pressure self-tightening structures, forming the first and second seals, respectively. The sealing tool body has a guide hole and a limiting shoulder inside, used for centering and axially limiting the inner steel pipe. The sealing cylinder is connected to the sealing tool body to form a closed sealing cavity, used to achieve double redundant sealing and external protection functions.

[0011] In some examples of this utility model, the sealing cylinder has a double-layer structure, including an inner sealing shell and an outer protective shell. The inner sealing shell is used to cover the lower sealing sleeve, and the outer protective shell is used to enhance corrosion resistance and impact resistance.

[0012] In some examples of this utility model, the sealing tool body is provided with multi-level limiting shoulders and V-shaped guide grooves inside. The limiting shoulders are used to match lower sealing sleeves of different heights, and the guide grooves are used to adapt to inner steel pipes of different diameters.

[0013] In some examples of this utility model, the upper sealing sleeve includes a rotating outer shell, a spiral wedge clamping mechanism, and a radial expansion sealing ring. The clamping mechanism is threadedly connected to the rotating outer shell and is used to drive the sealing ring to expand and fit against the inner steel tube.

[0014] In some examples of this utility model, an installation auxiliary tool is also included, which includes a guide sleeve and a torque limiting device. The guide sleeve is used to position the inner steel pipe, and the torque limiting device is used to control the clamping torque of the sealing sleeve.

[0015] In some examples of this utility model, the connection between the sealing tool body and the sealing cylinder is provided with a radial micro pressure detection hole, which is connected to an external pressure sensor interface for real-time monitoring of the pressure state inside the sealing cavity.

[0016] In some examples of this utility model, the upper sealing sleeve, the lower sealing sleeve, the sealing tool body, and the sealing cylinder are made of stainless steel or Inconel 625 alloy material to improve corrosion resistance, high pressure resistance, and high temperature resistance.

[0017] In some examples of this utility model, the inner wall of the sealing cylinder is provided with an annular backflow barrier groove to prevent external liquid from seeping upward along the outer wall of the inner steel pipe into the interior of the sealing cavity.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

[0019] This invention utilizes an upper and lower sealing sleeve at both ends of the inner steel tube of the optical cable, along with a high-pressure self-tightening structure, to create two independent sealing paths. This dual-sealing configuration not only maintains sealing redundancy even if one side fails, but also possesses excellent self-adaptability, maintaining a continuous seal in high-pressure, highly corrosive environments such as downhole oil and gas wells. This effectively prevents downhole liquids or gases from seeping up the optical cable path, significantly improving the overall safety and sealing reliability of the system. The sealing tool body, serving as the connecting hub, adopts a hollow metal shell design. Its internal structure features a limiting shoulder and guide holes, which, in conjunction with the outer diameter of the inner steel tube of the optical cable, effectively limit the axial position of the steel tube and provide coaxial guidance in the radial direction. This structural design allows for precise positioning of the steel tube during installation, preventing poor sealing contact caused by axial misalignment or radial eccentricity. This significantly improves the accuracy and stability of the sealing assembly, ensuring reliable operation of the sealing device under long-term high-temperature, high-pressure, and complex stress environments. The lower sealing sleeve is externally fitted with a sealing cylinder, which is threaded onto the external threaded section of the sealing tool body, forming a completely sealed cavity and structurally creating a second layer of protection for the lower sealing area. The sealing cylinder not only provides structural protection for the lower sealing sleeve but also enhances the mechanical strength and environmental adaptability of the outer shell through a double-shell design (optional). This gives the entire sealing structure resistance to mechanical impact, prevention of liquid backflow, and corrosion resistance, making it particularly suitable for subsea environments or downhole scenarios with highly corrosive fluid media. Furthermore, the overall structure is constructed from modular components. Each component, such as the sleeve, shell, and sealing cylinder, is connected by threads or plugs, facilitating rapid installation and disassembly in the field, effectively reducing construction complexity and reliance on manual labor, and adapting to various optical cable specifications and complex deployment requirements. This feature greatly improves the standardization and versatility of the sealing device, providing excellent engineering adaptability and ease of maintenance. In summary, the optical cable tail sealing device of this utility model not only has high sealing reliability and mechanical protection performance in structure, but also outperforms existing technologies in terms of installation accuracy, maintenance efficiency and environmental adaptability. It is particularly suitable for application scenarios with extremely high sealing safety requirements, such as oil and gas well downhole, deep-sea communication, and energy pipeline monitoring. Attached Figure Description

[0020] 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 from these drawings without creative effort.

[0021] Figure 1A schematic diagram of the optical cable tail sealing device provided by this utility model;

[0022] Figure 2 A cross-sectional structural schematic diagram of the optical cable tail sealing device provided by this utility model;

[0023] Figure 3 for Figure 2 Enlarged view of region A in the middle;

[0024] Figure 4 for Figure 2 Enlarged view of region B in the middle;

[0025] Figure 5 for Figure 2 A magnified view of region C in the middle.

[0026] Explanation of reference numerals in the attached figures:

[0027] 100 - Inner steel pipe; 110 - Upper sealing sleeve; 111 - Rotating outer shell; 112 - Spiral wedge clamping mechanism; 113 - Radial expansion sealing ring; 120 - Lower sealing sleeve;

[0028] 200 - Sealing tool body; 210 - Guide hole; 220 - Limiting shoulder; 230 - Multi-stage limiting shoulder; 240 - V-shaped guide groove;

[0029] 300 - Sealing cylinder; 310 - Inner sealing shell; 320 - Outer protective shell; 330 - Backflow barrier groove. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0031] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0032] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0033] The embodiments of this utility model are described in detail below. Examples of the 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 this utility model, and should not be construed as limiting this utility model.

[0034] Figure 1 A schematic diagram of the optical cable tail sealing device provided by this utility model; Figure 2 A cross-sectional structural schematic diagram of the optical cable tail sealing device provided by this utility model; Figure 3 for Figure 2 Enlarged view of region A in the middle; Figure 4 for Figure 2 Enlarged view of region B in the middle; Figure 5 for Figure 2 A magnified view of region C in the middle.

[0035] The following is for reference. Figures 1-5The optical cable tail-end sealing device according to an embodiment of the present invention includes: an upper sealing sleeve 110, which is fitted and pressed against the outer wall of the inner steel tube 100 of the optical cable; a sealing tool body 200, which is a hollow metal shell, fixedly connected to the lower end of the upper sealing sleeve 110; a lower sealing sleeve 120, which is inserted into the lower end outlet of the sealing tool body 200, fitted and pressed against the outer wall of the inner steel tube 100; and a sealing cylinder 300, which is fitted over the lower sealing sleeve 120 and fixed to the external threaded section of the sealing tool body 200 by a threaded connection; wherein... The inner steel pipe 100 is sequentially passed through the upper sealing sleeve 110, the sealing tool body 200, the lower sealing sleeve 120, and the sealing cylinder 300. The upper sealing sleeve 110 and the lower sealing sleeve 120 are both high-pressure self-tightening structures, forming the first seal and the second seal respectively. The sealing tool body 200 is provided with a guide hole 210 and a limiting shoulder 220 inside, which are used to center and guide the inner steel pipe 100 and limit its axial movement. The sealing cylinder 300 is connected to the sealing tool body 200 to form a closed sealing cavity, which is used to achieve double redundant sealing and external protection functions.

[0036] This invention utilizes a multi-stage structural combination to construct a tail-end optical cable sealing structure applicable to high-pressure and highly corrosive conditions. Its working principle involves the upper sealing sleeve 110 and the lower sealing sleeve 120 acting on both ends of the inner steel tube 100 of the optical cable, forming two independent high-pressure sealing paths. Both sleeves are self-tightening structures. During installation, driven by external tools or threaded mechanisms, their clamping components advance axially, driving the sealing ring to expand radially and adhere to the outer wall of the steel tube, forming a reliable sealing interface. When subjected to internal and external pressure differences, the sealing ring maintains a pre-tight state through elastic restoring force or a metal back support structure, ensuring long-term stable sealing performance. The sealing tool body 200 is a hollow metal shell that bears the structural load of the upper and lower sleeves. It has an internal limiting shoulder 220 for precisely controlling the insertion depth of the steel tube to prevent interference with the sealing position. A guide hole 210 is also provided for concentric positioning of the axis. This guide hole 210 is coaxially arranged with the upper and lower sleeves, forming a complete guide path to ensure uniform sealing. The lower sealing sleeve 120 is externally equipped with a sealing cylinder 300. The sealing cylinder 300 is connected to the external thread section of the sealing tool body 200 using a threaded structure. Its inner cavity covers the lower sealing sleeve 120, forming a closed sealing cavity. This threaded connection can be combined with a sealing ring or a tapered thread design to ensure that the connection part has gas-liquid sealing performance. The closed cavity not only improves the overall sealing level of the system, but also has good impact resistance, corrosion resistance, and external environmental barrier function. During installation, the entire device is sequentially fitted and connected from top to bottom along the inner steel pipe 100. Each structure is an independent module with clear coordination, enabling rapid installation, precise positioning, and the formation of a highly reliable tail-end closed sealing structure.

[0037] Through the above structural design and working principle, the optical cable tail sealing device provided by this utility model has dual independent sealing capabilities. Even in high-pressure or corrosive environments downhole, if any sealing part fails, the other can still maintain the sealing function, thereby significantly improving the sealing redundancy and safety of the system. The limiting shoulder 220 and guide hole 210 enable the inner steel tube 100 of the optical cable to be accurately limited and coaxially guided during installation, avoiding uneven force on the sealing ring or leakage due to eccentricity or misalignment. The sealing cylinder 300 not only provides an outer sealing structure, but also provides impact resistance and corrosion protection for the sealing area, forming an integrated protective sealing system. The overall device has a clear structure, a clear assembly sequence, and independently replaceable components, with excellent engineering adaptability and on-site implementation convenience. It is especially suitable for fields with extremely high sealing performance requirements, such as downhole oil and gas wells, submarine optical cables, and special signal transmission.

[0038] In other possible implementations, the upper sealing sleeve 110 and the lower sealing sleeve 120 may use self-tightening components with different structural forms, such as a double-cone clamping structure or a nested elastic ring structure, to adapt to different types of inner steel pipes 100. The material of the sealing tool body 200 may be selected from different metals, such as titanium alloy or high-strength aluminum alloy, depending on the application environment, to balance strength and weight requirements. The connection between the sealing cylinder 300 and the sealing tool body 200 may also adopt a quick-clamp structure or a flange bolt fastening method to suit different installation conditions. In addition, a waterproof absorbent layer or a vibration-damping pad may be optionally installed inside the sealing cavity to further improve sealing durability and environmental adaptability.

[0039] Please see Figure 1-2 According to the optical cable tail sealing device provided in this utility model embodiment, the sealing cylinder 300 has a double-layer structure, including an inner sealing shell 310 and an outer protective shell 320. The inner sealing shell 310 is threaded to the outer thread section of the sealing tool body 200 and is used to cover the lower sealing sleeve 120. The outer protective shell 320 is sleeved outside the inner sealing shell 310 and is used to enhance corrosion resistance and external impact resistance.

[0040] Based on the existing single-layer sealing cylinder 300 structure, this technical solution introduces a double-layer structure design, subdividing the sealing cylinder 300 into two functional substructures: an inner sealing shell 310 and an outer protective shell 320, which respectively undertake the functions of sealing cavity construction and structural protection. The inner sealing shell 310 is reliably connected to the outer thread section of the sealing tool body 200 through internal threads, forming an inner closed cavity, covering the lower sealing sleeve 120 and ensuring gas-liquid isolation in this area. The outer protective shell 320 is set outside the inner sealing shell 310 in a sleeve manner, forming a second protective structure. It can be fixed to the inner sealing shell 310 or the sealing tool body 200 through interference fit, clamp connection, or ring groove limiting. In principle, this double-layer structure adopts the concept of "separation design of sealing function and mechanical protection": the inner layer focuses on sealing and isolation performance, while the outer layer provides resistance to external impact, corrosion resistance, and environmental barrier performance, thus forming a sealing component with multiple barrier effects. Buffer gaps or shock-absorbing materials can be designed between the double-layer structures to further reduce the direct effect of external mechanical impact on the sealing layer.

[0041] By adopting a double-layer structure with a sealing cylinder 300, the overall sealing reliability of the device is enhanced, and its mechanical strength and corrosion resistance in complex engineering environments are significantly improved. The inner sealing shell 310 effectively covers and seals the lower sealing sleeve 120, ensuring that the sealing performance is not affected by external interference. The outer protective shell 320 forms an independent structural shell, which can effectively prevent external liquids, gases, particles, etc. from entering the sealing area, and has buffering and protection capabilities when encountering impact, vibration, or long-term pressure. This structure is particularly suitable for communication packaging applications with strong pressure disturbances downhole, salt spray corrosion on the seabed, or harsh operating conditions, which helps to improve the long-term stability and service life of the product, and has good engineering adaptability and scalability.

[0042] The inner sealing shell 310 can be made of flexible composite material or lined with fluororubber to improve its fit and chemical stability with the lower sealing sleeve 120. The outer protective shell 320 can be made of different metal materials, such as stainless steel 304 or 316L, or Inconel series corrosion-resistant alloys, to meet the needs of highly corrosive areas, depending on the operating environment. The cavity between the two layers can also be filled with anti-vibration silicone or nitrogen to further enhance impact cushioning and temperature isolation performance. Furthermore, the outer protective shell 320 can be equipped with inspection holes or sensor interfaces for real-time monitoring of the shell status or internal environmental changes, expanding system functionality.

[0043] Please continue reading Figures 1-4As shown, according to one embodiment of the present invention, the sealing tool body 200 is provided with a multi-level limiting shoulder 220 and a V-shaped guide groove 230 inside. The limiting shoulder 220 is used to match the lower sealing sleeve 120 of different heights, and the guide groove is used to adapt to the inner steel tube 100 of optical cable of different diameters to improve compatibility.

[0044] In the sealing tool body 200 structure of this utility model, a multi-stage limiting shoulder 220 and a V-shaped guide groove 230 are set in its internal through hole to form an adaptable structure for different types of lower sealing sleeves 120 and inner steel pipes 100. The multi-stage limiting shoulder 220 is arranged in a stepped structure on the inner wall of the hollow body, with different step positions having different axial heights, corresponding to the bottom positioning surfaces of lower sealing sleeves 120 at different heights, thereby automatically limiting the insertion according to the sleeve model selected on site, preventing insertion that is too deep or not in place. At the same time, the limiting shoulder 220 also plays a role in segmented axial pressure bearing, which helps to stabilize the sealing sleeve during the compression process. The V-shaped guide groove 230 is set near the inlet area of ​​the inner cavity of the body, and its two side slopes match the outer circle chamfer of the steel pipe. When the steel pipe is inserted, the guide groove can automatically correct it to the axial center position, improving coaxiality. The guiding structure is in principle a "progressive forced positioning" type. Its geometry can be adapted to the outer diameter of steel pipes of different specifications, and it has a certain degree of flexibility and compatibility, ensuring the symmetry of the sealing and bonding surface and the uniformity of the compression.

[0045] By incorporating multi-level limiting shoulders 220 and V-shaped guide grooves 230 within the sealing tool body 200, the device's dimensional compatibility and assembly precision are significantly enhanced. The limiting shoulders 220 enable rapid positioning and stable support for sealing sleeves 120 of different models, providing modular and standardized installation capabilities for the sealing structure. The V-shaped guide grooves 230 improve the coaxial accuracy of the steel pipe insertion, preventing leakage risks caused by uneven stress distribution in the sealing ring due to eccentricity. This structure not only facilitates quick adjustment and replacement of sealing components on-site according to different cable types but also reduces performance uncertainties caused by assembly errors, enhancing the system's engineering adaptability and practical feasibility.

[0046] The number and size of the limiting shoulders 220 can be flexibly set according to the expected height range of the lower sealing sleeve 120, such as setting three or five steps to cover commonly used size ranges. The guide groove structure can also be modified into a U-shaped or hemispherical groove to adapt to the positioning requirements of non-standard irregular steel pipes. To further improve processing and assembly flexibility, the shoulders and guide grooves can be designed as replaceable modular components, assembled in detachable slots within the sealing tool body 200, realizing modular upgrades and maintenance. In addition, the contact surfaces of the shoulders and guide grooves can be coated with an anti-wear layer or equipped with cushioning pads to extend service life and reduce the risk of assembly damage.

[0047] Please see Figure 3 According to another embodiment of the present invention, the upper sealing sleeve 110 includes a rotating outer shell 111, a spiral wedge clamping mechanism 112 and a radial expansion sealing ring 113. The clamping mechanism is threadedly connected to the rotating outer shell 111 and is used to drive the sealing ring to expand and fit against the inner steel tube 100.

[0048] In the upper sealing sleeve 110 structure of this utility model, a controllable radial expansion sealing mechanism is formed by combining a rotary-driven wedge-shaped clamping mechanism with an elastic sealing ring. The rotating outer shell 111 is the external main structure of the upper sealing sleeve 110. Its internal thread section cooperates with the external thread section of the internally located spiral wedge-shaped clamping mechanism 112 to form an axially advancing linkage. When the user rotates the outer shell 111, the thread drives the wedge structure to move along the sleeve axis. At the same time, the outside of the wedge structure forms a wedge surface contact with the radial expansion sealing ring 113. Under the action of axial displacement, the sealing ring is gradually pressed radially, causing it to expand and adhere tightly to the outer surface of the inner steel pipe 100, thus constructing a sealing interface. The sealing ring is preferably made of radially elastic rubber, fluororubber, or composite elastomer material, which has good rebound and pressure holding capacity under pressure. The entire clamping process is controlled by the user through rotation, which facilitates flexible adjustment of the clamping degree according to the on-site working conditions during installation, ensuring uniform force on the sealing ring and stable fit.

[0049] Through the above structural design, an adjustable and mechanically adaptive upper sealing sleeve 110 is formed. The cooperation between its rotating outer shell 111 and the wedge-shaped clamping mechanism realizes the progressive radial expansion and tightening of the sealing ring, effectively improving the sealing surface fit quality and pressure retention capability. This structure not only simplifies the installation process and reduces reliance on external tools, but also achieves controllability and repeatability of the clamping process through mechanical structure, reducing the risk of seal failure due to over-compression or under-compression. In addition, the elastic sealing ring has good resistance to high pressure, temperature difference, and corrosion, enabling the structure to maintain a stable sealing effect in variable environments. It is particularly suitable for applications with limited installation space and high sealing accuracy requirements, such as oil and gas wells and mine fiber optic cable terminals.

[0050] The expansion sealing ring can be made of nitrile rubber (NBR), fluororubber (FKM), or PTFE-coated elastomer to adapt to different temperature, corrosion, and pressure environments. The spiral wedge clamping mechanism 112 can be replaced with a sloping slider mechanism or a gear-driven slider structure to achieve different methods of axial transmission and radial compression. The rotating housing 111 can be designed as a precision structure with a graduated ring or locking mechanism to facilitate recording and fixing the clamping position. For frequent maintenance or large-volume assembly scenarios, electric or pneumatic tightening tools can be used to improve assembly efficiency.

[0051] According to another embodiment of the present invention, the optical cable tail sealing device further includes an installation auxiliary tool, which includes a guide sleeve and a torque limiting device. The guide sleeve is used to position the inner steel pipe 100, and the torque limiting device is used to control the clamping torque of the sealing sleeve.

[0052] This implementation optimizes the assembly process and improves sealing consistency by adding installation auxiliary tools. To ensure the alignment accuracy and sealing tightness of the device during installation, this embodiment incorporates dedicated installation auxiliary tools in its structural design. A guide sleeve, serving as a positioning component, is precisely inserted into the inner cavity of the sealing tool body 200. The inner hole of the sleeve precisely matches the outer diameter of the inner steel pipe 100, providing linear axial guidance during pipe insertion and limiting radial offset, thereby achieving coaxial insertion and ensuring uniform force on the sealing ring. A torque limiting device is used to adjust and control the force range of the sealing sleeve during the clamping process. This device typically consists of a setting spring, a limiting ring, and an externally adjustable torque knob. When the operator rotates the torque knob to clamp the sealing sleeve, the spring provides a reaction force, and the limiting ring controls its stroke. After reaching the set torque value, the knob will rotate freely to prevent further pressure application. Based on the principle of "force-position synchronous feedback", this structure ensures that the seal can be completed under a consistent clamping torque each time it is installed. This ensures that the sealing ring can fit fully without fatigue or damage caused by overpressure, thus enhancing the consistency and long-term stability of the sealing performance.

[0053] By incorporating a guide sleeve and a torque limiting device, the positioning accuracy and operational controllability of the optical cable tail-end sealing device during actual installation are effectively improved. The guide sleeve ensures that the inner steel tube 100 of the optical cable remains axially concentric when entering the sealing structure, avoiding problems such as uneven loading or poor contact on the sealing surface caused by eccentricity. The torque limiting device enables precise control of the sealing clamping force, transforming the assembly operation from relying on manual experience to a standardized process based on mechanical settings, thereby improving installation consistency, sealing reliability, and operational safety. This installation auxiliary system is particularly suitable for engineering applications with high sealing performance requirements, limited assembly space, or complex environments, providing important support for the promotion and standardized assembly of sealing devices.

[0054] The guide sleeve can be designed as a segmented, detachable structure, facilitating the replacement of steel pipes of different specifications. Magnetic or locating pins can also be used to assist in quick positioning. Torque limit devices can be mechanical ratchet, spring-sliding, or digital electronic torque wrenches; some types can also integrate data recording and alarm functions. For automated assembly lines, a servo drive control system combined with an image recognition system can be used to achieve precise guidance and positioning and automatic torque control, further improving production efficiency and quality traceability.

[0055] Please see Figure 2According to an optional embodiment of the present invention, a radial micro pressure detection hole is provided at the connection between the sealing tool body 200 and the sealing cylinder 300. The detection hole is connected to an external pressure sensor interface for real-time monitoring of the pressure state inside the sealing cavity.

[0056] This technical solution introduces a pressure sensing channel within the sealing structure to detect the internal state. A radially opened micro-detection hole is provided at the connection area between the sealing tool body 200 and the sealing cylinder 300 to achieve real-time extraction of the gas or hydraulic pressure inside the sealing cavity. This detection hole, typically 0.5~2 mm in size, is a transverse through-hole structure extending into the cavity, with a threaded or grooved structure at its outer end for connecting an external pressure sensor or data acquisition device. The detection hole is usually located near the threaded connection section between the sealing cylinder 300 and the body, avoiding damage to critical sealing surfaces while allowing direct access to the sealed cavity to accurately reflect changes in gas and liquid pressure within the cavity. Based on the "sealing state-cavity pressure correlation principle," this solution determines the presence of leakage trends by reading real-time pressure values ​​and comparing them with a reference pressure range, enabling real-time diagnosis and remote monitoring of the sealing structure.

[0057] By incorporating miniature pressure detection holes within the sealed structure and connecting them to external pressure sensors, real-time online monitoring of the internal gas pressure within the sealed cavity is achieved, significantly enhancing the device's intelligence and operational safety. This structure provides continuous assessment of the system's sealing performance without compromising seal integrity. Upon detecting abnormal pressure changes, it triggers alarms, shutdowns, or maintenance responses via signal feedback, preventing the escalation of accidents. Furthermore, this solution is easily integrated into remote data platforms, making it suitable for engineering applications requiring high reliability and continuous operation, such as downhole communication in oil and gas wells and deep-sea data acquisition systems. It endows the sealed structure with sensing and predictive capabilities, possessing high technological added value and promising industrial application prospects.

[0058] The placement of the detection holes can be optimized according to the cavity shape, and can be located on the side wall of the sealing cylinder 300, the upper end of the sealing tool body 200, or between the connecting thread sections. The pressure sensor interface can adopt a universal thread standard (such as G1 / 8, M10x1) or a quick-connect bayonet interface for rapid installation and removal. Sensor types can include MEMS miniature pressure chips, strain gauge pressure sensors, or fiber optic sensors to adapt to different response time and accuracy requirements. In high-safety-level scenarios, redundant sensors can be added, or a temperature sensor can be integrated for comprehensive environmental assessment, enhancing system robustness.

[0059] Please see Figure 1 , 2In one possible implementation, the upper sealing sleeve 110, the lower sealing sleeve 120, the sealing tool body 200, and the sealing cylinder 300 are made of stainless steel or Inconel 625 alloy to improve corrosion resistance, high pressure resistance, and high temperature resistance.

[0060] This implementation method utilizes high-performance metallic materials to manufacture key structural components of the sealing device, meeting the stringent requirements for durability, sealing stability, and safety in complex application environments. Stainless steel (such as 304 or 316L) possesses excellent corrosion resistance and mechanical strength, making it suitable for general industrial and outdoor applications. Inconel 625 alloy, as a nickel-based superalloy, exhibits extremely strong corrosion resistance, high-temperature resistance, and high-pressure resistance, making it particularly suitable for marine environments, high-temperature pipelines, and oil and gas extraction applications. By using the above materials to manufacture the upper sealing sleeve 110, lower sealing sleeve 120, sealing tool body 200, and sealing cylinder 300, the device can resist physical and chemical corrosion caused by moisture, salt spray, acids, alkalis, and high-pressure impacts during long-term operation, ensuring undamaged structural stability and long-lasting effective sealing.

[0061] The use of stainless steel or Inconel 625 alloy significantly improves the environmental adaptability and service life of the entire sealing system. Compared to ordinary carbon steel or engineering plastics, these materials exhibit lower fatigue decay rates and higher fracture toughness under conditions of strong corrosion, high pressure, and temperature variations, effectively reducing the risk of seal failure due to material aging, corrosion, or thermal expansion and contraction. Furthermore, this material selection supports long-term maintenance-free operation of the device, reduces the frequency of inspections and replacements, lowers operating and maintenance costs, and improves the overall system reliability and economy.

[0062] In specific applications, appropriate material combinations can be chosen based on the usage environment. For example, the sealing tool body 200 can be made of Inconel 625 to improve pressure and heat resistance, while the sealing cylinder 300 can be made of 316L stainless steel to balance corrosion resistance and cost. For certain weight-sensitive applications, some components can be replaced with lightweight, high-strength materials such as titanium alloys and aluminum alloys. For applications sensitive to electrochemical corrosion, sacrificial anode protection technology or anodized coatings can be used to further enhance overall corrosion resistance. In addition, the surface of components can be subjected to surface strengthening treatments such as nitriding, ceramic spraying, or PVD coating to enhance wear resistance and chemical inertness, expanding the product's applicability.

[0063] Please see Figure 5 In one possible implementation, the inner wall of the sealing cylinder 300 is provided with an annular backflow barrier groove 330 to prevent external liquid from seeping upward along the outer wall of the inner steel pipe 100 into the interior of the sealing cavity.

[0064] This implementation method constructs a physical liquid permeation barrier by setting an annular backflow barrier groove 330 on the inner wall of the sealing cylinder 300, thereby enhancing the sealing structure's resistance to liquid backflow. This barrier groove is typically machined as an annular groove or protrusion structure, with a hook-shaped, sawtooth-shaped, or stepped cross-section, and is located in the middle of the sealing cylinder 300 or near the outlet area. When external liquids (such as water vapor, oil mist, or other media) attempt to seep upwards through the tiny gap between the inner steel pipe 100 and the sealing cylinder 300, the backflow groove effectively prevents it from further entering the sealed cavity by interrupting the liquid's capillary ascent path, increasing the interface contact angle, and guiding the liquid backflow. Combined with a dual high-pressure self-tightening sealing structure, this further constitutes an integrated "structure + function" anti-seepage system.

[0065] The annular backflow barrier 330 features a simple design and is easy to manufacture, yet it significantly enhances the backflow resistance of the sealing cylinder 300, making it particularly suitable for use in high-humidity, liquid-immersed, or underground communication well environments. By physically blocking the liquid propagation path, it achieves long-term protection without relying on additional sealants or special coatings, preventing external liquids from seeping into the sealed cavity and causing component corrosion, performance degradation, or damage to fiber optic cable insulation, thus improving system stability and operational reliability. Furthermore, this structure requires no maintenance, is suitable for long-term deployment, adapts to different installation orientations and site angle changes, and possesses excellent versatility and engineering value.

[0066] The design of barrier tanks can be adjusted based on the type of target liquid, flow path, and changes in environmental pressure. For example, multi-stage stepped tanks, multi-layered impermeable labyrinth structures, or alternating hydrophilic / hydrophobic designs can be used to enhance liquid barrier capabilities. For more demanding applications, the tank interior can be filled with materials with adsorption or expansion properties, such as bentonite sealant or hydrogel gaskets, to enhance emergency seepage prevention. The tank material can also undergo surface roughening treatment to improve the contact angle and drainage efficiency, or be coated with hydrophobic / oleophobic coatings to enhance liquid repulsion. In vibrating environments, an elastic connection structure between the tank and the cylinder wall can be considered to absorb shock and slow down dynamic liquid rise.

[0067] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0068] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An optical cable field seal, comprising: The utility model relates to a sealing tool for optical cable, which comprises: an upper sealing sleeve, which is sleeved and compressed on the outer wall of the inner steel tube of the optical cable; a sealing tool body, which is a hollow metal shell and is fixedly connected to the lower end of the upper sealing sleeve; a lower sealing sleeve, which is inserted into the lower end outlet of the sealing tool body and is sleeved and compressed on the outer wall of the inner steel tube; a sealing cylinder, which is sleeved on the outside of the lower sealing sleeve and is fixed on the external thread section of the sealing tool body through thread connection; wherein the inner steel tube sequentially passes through the upper sealing sleeve, the sealing tool body, the lower sealing sleeve and the sealing cylinder; the upper sealing sleeve and the lower sealing sleeve are both high-pressure self-tightening structures, and form the first and second seals respectively; the sealing tool body is internally provided with a guide hole and a limiting shoulder, which are used for centering and guiding and axially limiting the inner steel tube; the sealing cylinder and the sealing tool body are connected to form a closed sealing cavity, which is used for realizing double-redundancy sealing and external protection.

2. The optical cable stub seal apparatus of claim 1, wherein: The sealing cylinder is a double-layer structure, comprising an inner sealing shell and an outer protective shell, the inner sealing shell is used for covering the lower sealing sleeve, and the outer protective shell is used for enhancing the corrosion resistance and impact resistance.

3. The optical cable stub seal of claim 1, wherein: The sealing tool body is internally provided with a multi-stage limiting shoulder and a V-shaped guide groove, the limiting shoulder is used for matching lower sealing sleeves of different heights, and the guide groove is used for adapting to inner steel tubes of different diameters.

4. The optical cable stub seal of claim 1, wherein: The upper sealing sleeve comprises a rotating shell, a spiral wedge-shaped compression mechanism and a radial expansion sealing ring, the compression mechanism is threadedly connected with the rotating shell and is used for driving the expansion of the sealing ring and the adhesion to the inner steel tube.

5. The optical cable stub seal apparatus of claim 1, wherein: The installation auxiliary tool comprises a guide sleeve and a torque limiting device, the guide sleeve is used for positioning the inner steel tube, and the torque limiting device is used for controlling the compression torque of the sealing sleeve.

6. The optical cable stub seal apparatus of any of claims 1-5, wherein: The connecting part of the sealing tool body and the sealing cylinder is provided with a radial micro pressure detection hole, which is connected to an external pressure sensor interface and is used for real-time monitoring of the pressure state in the sealing cavity.

7. The optical cable stub seal of claim 1, wherein: The upper sealing sleeve, the lower sealing sleeve, the sealing tool body and the sealing cylinder are made of stainless steel or Inconel 625 alloy material, which is used for improving the corrosion resistance, high-pressure resistance and high-temperature resistance.

8. The optical cable stub seal of claim 1, wherein: The inner wall of the sealing cylinder is provided with an annular backflow blocking groove, which is used for preventing external liquid from penetrating into the sealing cavity along the outer wall of the inner steel tube.

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