Differential Pressure Flow Measurement Diagnostics

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Solution Overview

Problem

Existing flow measurement systems in industrial processes face challenges in accurately detecting issues such as plugged impulse lines, incorrect differential pressure readings, and primary element blockages, as they rely on statistical variations and require complete mass flow calculations, which are complex and not always precise.

Innovation Solution

A system utilizing two differential pressure transmitters to measure traditional and permanent pressure losses across a flow restriction element, with a data link for communication, performs diagnostics by monitoring the pressure loss ratio, allowing for the detection of system problems without the need for complete mass flow calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complete mass flow calculations are performed for flow measurement diagnostics, then diagnostic accuracy is improved, but system complexity and computational requirements increase

Engineering Contradiction:
Improvediagnostic accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and monitors specific differential pressure parameters (ΔP1, ΔP2, ΔP3) separately from the complete mass flow calculation process. By taking out these individual pressure differential measurements and monitoring them independently through the data link, the system achieves diagnostic capability without requiring full mass flow calculations, thus reducing system complexity while maintaining diagnostic accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs preliminary monitoring of differential pressure trends across the restriction element before problems fully develop. By continuously measuring and comparing ΔP1, ΔP2, and ΔP3 values through the data link, the system detects anomalies in advance, enabling early diagnostics without waiting for complete mass flow calculation data that would indicate established problems.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If statistical variation methods are used for detecting flow measurement issues, then system complexity is reduced, but detection reliability deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoiddetection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where differential pressure measurements (ΔP1, ΔP2, ΔP3) are continuously monitored and compared against expected relationships through the data link. When deviations from the expected pressure differential patterns occur, the system provides feedback signals indicating potential problems such as plugged impulse lines or restriction element issues, thereby improving detection reliability through systematic comparison rather than random statistical variation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system establishes preliminary diagnostic criteria based on the relationship between differential pressure measurements before problems occur. By pre-defining the expected relationships among ΔP1, ΔP2, and ΔP3 and monitoring for deviations, the system reliably detects issues without requiring complex statistical analysis, achieving both simplicity and reliability.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple differential pressure transmitters are used to monitor pressure loss ratio trends, then diagnostic capability is improved, but device complexity increases

Engineering Contradiction:
Improvediagnostic capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple differential pressure measurements (ΔP1, ΔP2, ΔP3) from separate transmitters into a unified diagnostic parameter called the pressure loss ratio. By merging these individual measurements and monitoring their combined trend through the data link, the system achieves comprehensive diagnostic capability while presenting a single integrated view, effectively reducing the perceived complexity despite using multiple transmitters.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The differential pressure transmitters and data link system serve multiple functions: they measure individual pressure differentials, calculate the pressure loss ratio trend, detect various types of faults (plugged lines, restriction element problems), and provide diagnostic information. This multi-functionality justifies the use of multiple transmitters while maximizing their utility across different diagnostic needs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables efficient detection of flow system issues, such as plugged lines or obstructed elements, through trends in pressure loss ratio variations, providing early alerts and reducing the complexity of diagnostics, while maintaining accuracy.

Implementation Method 1

a first differential pressure transmitter is configured to measure a first differential pressure in the process fluid due to flow of process fluid past the flow restriction element

Methodology Applied
Scientific EffectDifferential pressure measurement: Pressure Drop

Data Source

PatentEP2681516B1Differential pressure based flow measurement
Publication Date: 2023.04.12 ROSEMOUNT INC
  • EP2681516B1 patent drawingFigure 1A~1B
  • EP2681516B1 patent drawingFigure 2
  • EP2681516B1 patent drawingFigure 3

AI summary

A system (102) for measuring flow of process fluid through process piping (106) in an industrial process includes a flow restriction element (110) in the process pipe. A first differential pressure transmitter (124) is configured to measure a first differential pressure across the flow restriction element (110) in response to flow of process fluid (104). A second differential pressure transmitter (130) configured to measure a second differential pressure in the process fluid (104) across the flow restriction element (110). Circuitry performs diagnostics based upon the first differential pressure and the second differential pressure.