Optical Process Variable Measurement Without Intrusive Sensors

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Solution Overview

Problem

Existing process variable measurement technologies often require intrusive sensors that directly or indirectly couple with process fluids, leading to reliability issues, safety concerns, environmental impacts, increased costs, and reduced operational flexibility.

Innovation Solution

The use of image capture devices to detect the relative mechanical motion of a process component, which correlates with process variables such as flow rate, level, or pressure, allowing for non-intrusive measurement through image processing and output circuitry, enabling accurate measurement without direct contact with the process fluid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If intrusive sensors are used to measure process variables, then measurement capability is achieved, but reliability deteriorates due to direct contact with process fluid

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsensor intrusion complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary optical system consisting of a light source, optical path, and image capture device that mediates between the measurement objective and the process fluid. This optical intermediary allows measurement without direct contact, resolving the contradiction by enabling reliable measurements while eliminating sensor intrusion into the process fluid.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical/intrusive sensor system with an optical measurement system. Instead of using physical sensors that must contact the process fluid, the system uses light interaction with process components to derive measurements, thereby improving reliability while maintaining measurement capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If intrusive sensors are used to measure process variables, then measurement capability is achieved, but safety deteriorates due to exposure to hazardous process fluids

Engineering Contradiction:
Improvemeasurement safetyVSAvoidsensor exposure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The optical system serves as a safety intermediary, allowing measurements to be taken without exposing sensors to hazardous process fluids. The light-based measurement path remains external to the process fluid, eliminating safety risks while maintaining measurement functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent substitutes mechanical sensors that require physical exposure to process fluids with an optical measurement system. This replacement eliminates the safety hazards associated with sensor exposure to hazardous materials while preserving the ability to measure process variables.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If intrusive sensors are used to measure process variables, then measurement capability is achieved, but operational flexibility deteriorates due to installation and maintenance constraints

Engineering Contradiction:
Improveoperational flexibilityVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The optical system provides installation flexibility by serving as an external measurement intermediary. Sensors and optical components can be positioned away from the process fluid, allowing easier installation, access, and maintenance without requiring intrusion into the process stream or shutdown of the process equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces intrusive mechanical sensors with an optical measurement system that offers superior operational flexibility. The external optical components can be installed and maintained without process shutdown, and the system adapts to various process configurations without requiring direct sensor contact with the process fluid.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If image capture device moves with process component, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvemotion detection accuracyVSAvoidimage capture system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the image capture device with the process component, creating an integrated measurement system. This merging allows the sensor to move with the component, maintaining accurate relative position measurements while reducing the need for complex external mounting and alignment systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The image capture device is nested within or integrated into the process component structure. This nesting arrangement allows the sensor to travel with the component while using the component's own motion as the reference frame, simplifying the overall system architecture while maintaining measurement precision.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

This approach enhances measurement reliability, safety, and operational flexibility while reducing costs and environmental concerns by providing a non-intrusive method for monitoring process variables, such as flow rate and pressure, using image capture and processing techniques.

Implementation Method 1

The image captures device is configured to capture an image which changes due to the repetitive relative mechanical motion of the process component

Methodology Applied
Scientific EffectOptical imaging: Photography

Data Source

PatentEP3049878B1Process device with process variable measurement using image capture device
Publication Date: 2021.06.02 ROSEMOUNT INC
  • EP3049878B1 patent drawingFigure 1
  • EP3049878B1 patent drawingFigure 2
  • EP3049878B1 patent drawingFigure 3

AI summary

A field device (12) for monitoring a process variable of an industrial process includes an image capture device (100). A process component (106) exhibits relative motion as a function of a process variable. The image captures device (100) captures an image which changes due to the relative motion of the process component (106). An image processor (102) coupled to the image capture device (100) detects relative motion of the process component (106) and measures the process variable based upon the detected relative motion. Output circuitry (30) provides an output related to the measured process variable.