Single-Crystal Pressure Probe for Subsea High-Pressure Measurement

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Solution Overview

Problem

High-pressure subsea environments pose challenges for pressure measurement systems due to extreme pressures and corrosion, requiring robust and reliable pressure barriers that are cost-effective, compact, and capable of containing flammable or explosive process fluids, with existing designs facing issues of reliability, safety, size, and cost, especially in systems that need two barriers between the process fluid and seawater.

Innovation Solution

A high-integrity pressure measurement system utilizing a single-crystal pressure sensor directly contacting the process fluid, with a secondary metallic barrier isolated by a primary barrier, and a single-crystal feedthrough acting as a secondary pressure barrier, designed to withstand extreme pressures and corrosion, while minimizing size and cost through a compact architecture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant pressure barriers are provided to ensure safety and robustness, then reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepressure barrier reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressure measurement system is segmented into distinct functional zones: a process fluid barrier containing the pressure sensor for direct process fluid contact, and a separate electronic compartment barrier containing electronic components. This segmentation allows each barrier to be optimized independently while maintaining overall system reliability through redundancy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A hermetically sealed feedthrough acts as an intermediary element connecting the process fluid barrier to the electronic compartment barrier. This feedthrough provides both mechanical support and electrical connectivity while maintaining the integrity of the pressure barrier, enabling redundant barrier design without excessive complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If pressure barriers are designed to withstand 50,000 psi for 20,000 psi MWP applications, then safety is improved, but manufacturing cost and difficulty increase

Engineering Contradiction:
Improvepressure barrier safetyVSAvoidbarrier manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The overall pressure containment requirement is segmented across two separate barriers: the process fluid barrier designed for direct process fluid containment and the electronic compartment barrier designed for electronic component protection. Each barrier can be manufactured to appropriate pressure ratings without requiring the entire system to be over-engineered for maximum pressure scenarios.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design parameters for each pressure barrier are optimized based on their specific functional requirements and failure consequences. The process fluid barrier parameters are selected for direct process fluid containment, while the electronic compartment barrier parameters are selected for electronic component protection, allowing cost-effective manufacturing tailored to each zone's needs.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If single-crystal materials are used for pressure sensor and feedthrough, then reliability and corrosion resistance are improved, but manufacturing cost increases

Engineering Contradiction:
Improvecomponent reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Single-crystal materials are applied locally to specific components where their properties provide maximum benefit: the pressure sensor element requires single-crystal material for piezoresistive properties and corrosion resistance in direct process fluid contact, while the feedthrough benefits from single-crystal material for mechanical strength and hermetic sealing. Other components can use more cost-effective materials.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system employs a composite material strategy combining single-crystal materials with other materials optimized for their specific functions. Single-crystal materials provide the critical pressure sensing and hermetic sealing functions, while other materials handle structural support and electrical connectivity, achieving reliability without excessive cost.

Inventive Principle:
Principle #40Composite materials

4Reliability

If the pressure sensor is spaced from the feedthrough, then the secondary barrier is isolated from process fluid, but device complexity increases

Engineering Contradiction:
Improvebarrier isolationVSAvoidcomponent arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The feedthrough serves as an intermediary element that bridges the spaced-apart pressure sensor and electronic components while maintaining barrier isolation. This intermediary provides both mechanical mounting and electrical connectivity, enabling the pressure sensor to be positioned optimally for process fluid contact while keeping electronic components isolated in the sealed compartment.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system provides a reliable, safe, and cost-effective high-pressure measurement solution with reduced size and complexity, ensuring containment of process fluids and enabling long-term operation in harsh subsea conditions with improved reliability and reduced maintenance costs.

Implementation Method 1

The pressure of the process fluid causes a physical deformation to the pressure sensor which generates an associated electrical change in the pressure sensor

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

A feedthrough is formed of a single crystal material and has a plurality of conductors extending from a first end to a second end

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3014235B1High integrity process fluid pressure probe
Publication Date: 2019.09.18 ROSEMOUNT INC
  • EP3014235B1 patent drawingFigure 1~2
  • EP3014235B1 patent drawingFigure 3~4
  • EP3014235B1 patent drawingFigure 5~6

AI summary

A process fluid pressure measurement probe (100) includes a pressure sensor (112) formed of a single-crystal material and mounted to a first metallic process fluid barrier (130) and disposed for direct contact with a process fluid. The pressure sensor (112) has an electrical characteristic that varies with process fluid pressure. A feedthrough (122) is formed of a single-crystal material and has a plurality of conductors extending from a first end to a second end. The feedthrough (122) is mounted to a second metallic process fluid barrier (116) and is spaced from, but electrically coupled to, the pressure sensor (112). The pressure sensor (112) and the feedthrough (122) are mounted such that the secondary metallic process fluid barrier (116) is isolated from process fluid by the first metallic process fluid barrier (116).