Mineral Insulated Cable Secondary Seal for Pressure Sensors
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Solution Overview
Problem
Industrial pressure measurement systems face challenges with pressure barriers regarding cost, complexity, size, reliability, and compliance, which are essential for ensuring the safety of plant personnel and maintaining the integrity of process fluids.
Innovation Solution
The use of a mineral insulated (MI) cable as a secondary seal in pressure measurement systems, leveraging its robustness and high-temperature capabilities, provides a configurable and cost-effective solution by acting as a secondary seal, supporting pressure sensors and allowing direct contact with process fluids without the need for additional isolation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional pressure barrier systems are used with redundant barriers, then safety and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the cable assembly and seal function into a single integrated mineral insulated cable unit. The metallic sheath serves dual purposes as both cable protection and secondary pressure barrier seal, eliminating the need for separate seal components and reducing overall system complexity while maintaining redundant barrier safety
Solution Approach 2:
The mineral insulated cable's metallic sheath performs multiple functions simultaneously: it provides electrical insulation for the conductors, acts as a mechanical protective barrier, and serves as a pressure-containing seal at the vessel interface. This multi-functionality reduces the number of components needed while maintaining reliability
2Reliability
If traditional isolation systems are used, then pressure barrier reliability is improved, but device size and cost increase
Solution Approach 1:
The patent integrates the isolation function directly into the cable assembly by making the metallic sheath itself the sealing barrier. This eliminates the need for separate isolation diaphragms, capillary tubes, and remote seal assemblies, significantly reducing the overall system volume while maintaining pressure barrier reliability
3Device complexity
If mineral insulated cable is used as secondary seal, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise material parameters and dimensional tolerances for the metallic sheath thickness, conductor spacing, and mineral insulation density to ensure the cable can function as a reliable pressure barrier. These controlled parameters enable the simplified design to meet safety requirements without requiring complex assembly procedures
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 MI cable system offers a reliable, cost-effective, and compact solution for pressure measurement, capable of withstanding high pressures and temperatures, while ensuring containment of process fluids and reducing the complexity of pressure barrier systems, thus enhancing safety and operational efficiency.
Implementation Method 1
The mineral insulated cable includes a plurality of conductors extending within the metallic sheath and being spaced from one another by an electrically insulative dry mineral
Implementation Method 2
The proximal end of the metallic sheath is configured to be sealingly attached to a process fluid vessel
Data Source
AI summary
A pressure measurement system is provided. The system includes a pressure sensing probe extendable into a process fluid and having a pressure sensor with an electrical characteristic that varies with process fluid pressure. A mineral insulated cable has a metallic sheath with a distal end attached to the pressure sensing probe and a proximal end. The mineral insulated cable includes a plurality of conductors extending within the metallic sheath and being spaced from one another by an electrically insulative dry mineral. The proximal end of the metallic sheath is configured to be sealingly attached to a process fluid vessel.