Submarine Cable Joint Box Double Sealing for Deepwater Pressure

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Solution Overview

Problem

Conventional submarine cable joint boxes fail to meet the waterproof sealing requirements in deepwater areas, particularly at depths greater than 100 meters, due to the limitations of single-layer fluororubber sealing rings and heat shrink tubes.

Innovation Solution

A submarine cable joint box design incorporating a sealing cylinder with sealing ends and a heat shrink tube, where the sealing cylinder is sleeved on an intermediate connector, and the submarine cables at both ends are connected with sealing ends forming an accommodation chamber filled with a waterproof sealant, combined with a heat shrink tube for enhanced sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-layer fluororubber sealing ring and heat shrink tube are used for sealing, then the structure is simple, but the waterproof sealing performance cannot meet the requirements in deepwater areas

Engineering Contradiction:
Improvewaterproof sealing performanceVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a multi-layer nested sealing structure where the fluororubber sealing ring is placed inside the heat shrink tube, creating a nested configuration. The sealing end is further nested within the sealing cylinder. This nested arrangement allows multiple sealing mechanisms to work together, providing redundant sealing protection that meets deepwater waterproof requirements while maintaining reasonable structural complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent combines different sealing materials with complementary properties: fluororubber provides chemical resistance and elasticity, while the heat shrink tube provides thermal contraction sealing. This composite sealing approach leverages the strengths of different materials to achieve superior waterproof performance in deepwater environments

Inventive Principle:
Principle #40Composite materials

2Stress or pressure

If the joint box uses conventional sealing methods, then the manufacturing process is simple, but it cannot withstand high seawater pressure at depths greater than 100 meters

Engineering Contradiction:
Improveseawater pressure resistanceVSAvoidsealing structure manufacturing
Core Design Contradiction:
Stress or pressureVSEase of manufacture

Solution Approach 1:

The sealing end is nested within the sealing cylinder, creating a protected internal sealing environment. This nested configuration allows the sealing components to be pre-assembled and tested before final installation, simplifying the manufacturing process while ensuring the structure can withstand high seawater pressures at depths greater than 100 meters

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The sealing system is divided into distinct functional segments: the fluororubber sealing ring for primary sealing, the heat shrink tube for secondary sealing and protection, and the sealing cylinder for structural support and pressure distribution. This segmentation allows each component to be manufactured and quality-tested separately, improving ease of manufacture while achieving the required pressure resistance

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design achieves improved sealing performance by preventing external water from entering the joint, reducing the impact of seawater pressure on the submarine cables, and ensuring reliable operation in deepwater environments up to 500 meters.

Implementation Method 1

the heat shrink tube is sleeved on the sealing cylinder and the sealing ends, and two ends of the heat shrink tube are in heat shrink connection with the submarine cables at the two ends respectively

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP4683147A1Submarine cable joint box and submarine cable system
Publication Date: 2026.01.21 ZHONGTIAN TECH MARINE SYST CO LTD
  • EP4683147A1 patent drawingFigure 1
  • EP4683147A1 patent drawingFigure 2
  • EP4683147A1 patent drawingFigure 3

AI summary

The present application relates to the technical field of submarine cable fittings, and provided are a submarine cable joint box and a submarine cable system. Two submarine cables are joined by an intermediate connector. The submarine cable joint box includes: sealing ends, a sealing cylinder and a heat shrink tube, where the sealing cylinder is sleeved on the intermediate connector; the submarine cables at two ends of the intermediate connector are respectively sleeved with the sealing ends; two ends of the sealing cylinder are in sealed connection with the corresponding sealing ends respectively. The two sealing ends, the sealing cylinder and the intermediate connector form an accommodation chamber, and the accommodation chamber is filled with a waterproof sealant. The heat shrink tube is sleeved on the sealing cylinder and the sealing ends, and two ends of the heat shrink tube are in heat shrink connection with the submarine cables at the two ends respectively. The present application uses the mode of combining the sealing ends and the heat shrink tube to perform double sealing, thereby improving the sealing performance of the repair joint box in deepwater areas.