Flexible Pressure-Balanced Cable Assembly With Segmented O-Ring Seals
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Solution Overview
Problem
Traditional pressure-balanced cable assemblies are often bulky, expensive, and lack redundancy, making them unreliable in environments with varying pressures, such as downhole oil wells, where they also face challenges with thermal expansion mismatch between metal components and dielectric fluids.
Innovation Solution
A flexible, pressure-balanced cable assembly using a tubular-shaped plastic sleeve with multiple O-ring seals and dielectric fluid-filled chambers, where each O-ring is independently movable to balance pressure differentials, providing redundancy and a low-profile design that matches thermal expansion rates with the insulative shield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pressure-balanced cable assemblies are used, then pressure balancing function is provided, but the assembly becomes bulky and expensive
Solution Approach 1:
The cable assembly is segmented into multiple discrete chambers separated by O-ring seals, allowing each chamber to independently balance pressure. This segmentation enables the use of smaller, more manageable components rather than a single large pressure-balancing structure.
Solution Approach 2:
The patent employs flexible O-ring seals and a streamlined outer sheath instead of rigid metal components. The flexible nature of these elements allows for a more compact design while maintaining pressure-balancing functionality, eliminating the need for bulky traditional metal construction.
2Reliability
If traditional pressure-balanced cable assemblies are used, then pressure balancing function is provided, but the assembly becomes expensive
Solution Approach 1:
The patent replaces expensive metal pressure-balancing components with inexpensive O-ring seals and flexible tubing. These simpler, cheaper components achieve the same pressure-balancing function, significantly reducing manufacturing costs while maintaining reliability through redundancy.
Solution Approach 2:
Instead of using a single complex metal pressure-balancing mechanism, the patent uses multiple simple O-ring seal copies arranged in series. This approach achieves redundancy and reliability through repetition of simple, low-cost elements rather than through expensive complex mechanisms.
3Reliability
If multiple O-ring seals are used, then redundancy and reliability are improved, but the assembly complexity increases
Solution Approach 1:
Each O-ring seal performs multiple functions: it separates chambers, provides a pressure seal, and acts as a movable pressure-balancing element. This multi-functionality reduces the need for additional dedicated components, simplifying the overall assembly despite the presence of multiple seals.
Solution Approach 2:
The patent combines the functions of chamber separation, pressure sealing, and pressure balancing into a single O-ring seal element. By merging these functions into one component rather than using separate elements for each function, the design reduces overall complexity while maintaining redundancy.
4Strength
If metal components are used in traditional assemblies, then structural strength is provided, but thermal expansion mismatch with dielectric fluid occurs
Solution Approach 1:
The patent uses composite construction with flexible tubing (polymer material) and O-ring seals (elastomeric material) that have thermal expansion properties more closely matched to the dielectric fluid. This composite approach maintains structural integrity while eliminating thermal expansion mismatch problems associated with metal components.
Solution Approach 2:
The patent changes the material parameters of the outer sheath and sealing elements from metal to flexible polymer materials. This parameter change in material composition adjusts the thermal expansion characteristics to be compatible with the dielectric fluid, preventing the thermal expansion mismatch that occurs with metal components.
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 solution results in a cost-effective, reliable, and flexible cable assembly that maintains pressure balance and protects electrical cables from environmental hazards with improved thermal compatibility, ensuring high reliability in challenging environments.
Implementation Method 1
The seals are independently movable along the electrical cable in response to differences between a pressure within a respective chamber and a pressure outside of the respective chamber
Implementation Method 2
dielectric fluid is contained within each of the plurality of chambers
Data Source
AI summary
Some embodiments include a flexible, pressure-balanced cable assembly. The cable assembly has a tubular-shaped flexible outer sleeve that surrounds an electrical cable. A plurality of seals is positioned along the length of the flexible sleeve within the space formed between the inner surface of the flexible sleeve and the outer surface of the electrical cable. The seals partition the space into a plurality of individual chambers. Each chamber is filled with dielectric fluid. The seals are independently and bi-directionally movable in response to a pressure difference between the inside of the cable assembly and the external environment thereby balancing the pressure between the inside of the cable assembly and the external environment.