Flow Metering Diagnostics Using Differential and Static Pressure
Solution Overview
Problem
Prior art diagnostics techniques for flow metering systems based on differential pressure measurements are complex due to the need for multiple mass flow calculations and calibrations, making them cumbersome and difficult to manage.
Innovation Solution
A method and system that utilize one differential pressure transmitter and multiple absolute pressure transmitters to perform diagnostics, simplifying the process by measuring static pressures upstream and downstream of a fluid obstruction, and calculating diagnostic parameters from these measurements to identify issues without requiring mass flow calculations or extensive calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple differential pressure transmitters are used for diagnostics, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple pressure measurements (differential pressure across the flow restriction element and static pressure upstream) into a unified diagnostic system. By merging these measurements and processing them through a single system with a processor, the patent achieves diagnostic capabilities comparable to multiple independent transmitters while reducing overall system complexity and cost.
Solution Approach 2:
The processor in the patent performs multiple functions: it calculates flow rate from differential pressure, calculates static pressure from the upstream pressure tapping, and performs diagnostic comparisons between measured and expected values. This multi-functionality replaces what would traditionally require multiple specialized transmitters, reducing device complexity while maintaining diagnostic precision.
2Measurement precision
If multiple mass flow calculations are performed for diagnostics, then diagnostic accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The system performs self-diagnosis by automatically comparing measured static pressure against expected static pressure calculated from differential pressure measurements and flow rate equations. The processor autonomously identifies discrepancies without requiring manual calculations or complex diagnostic procedures, improving ease of operation while maintaining diagnostic accuracy.
Solution Approach 2:
The system continuously monitors the difference between measured and expected static pressure values, providing ongoing feedback on system health. This automated feedback mechanism simplifies operation by continuously assessing diagnostic parameters without requiring manual intervention or complex calculation procedures.
3Measurement precision
If extensive calibration is performed, then measurement precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The system performs preliminary calculations of expected static pressure based on differential pressure measurements and established flow equations during normal operation. By pre-calculating and continuously updating expected values based on actual operating conditions, the system reduces the need for extensive field calibration while maintaining measurement precision.
Solution Approach 2:
The system adapts to changing operating conditions by continuously recalculating expected static pressure based on current differential pressure measurements and flow rates. This dynamic parameter adjustment allows the system to maintain accuracy across varying conditions without requiring extensive calibration for each specific operating scenario, simplifying installation and commissioning.
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 simplifies diagnostics by relying on fewer pressure measurements, allowing for easier identification of problems with the flow restriction element and static pressure measurement, reducing complexity and the need for calibration, while providing more accurate and sensitive detection of system issues.
Implementation Method 1
measuring a differential pressure taken between a first conduit position upstream of the fluid obstruction and a second conduit position downstream of the fluid obstruction
Implementation Method 2
The differential pressure can be measured by a differential pressure transmitter and used to calculate the flow of process fluid. The equation also requires the density of the fluid that is typically calculated by a flow computer based on a pressure and temperature measurement.
Implementation Method 3
Differential pressure flow measurement is based on a flow restriction element that creates a pressure drop in the process fluid
Data Source
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AI summary
The invention is about a method and a system of metering flow through a fluid conduit, which comprises a fluid obstruction, the method comprising the steps of measuring a differential pressure (dP) taken between a first conduit position upstream of the fluid obstruction and a second conduit position downstream of the fluid obstruction, and calculating a fluid flow rate using the differential pressure (dP) measurement, wherein the method further comprises the steps of - measuring a first static pressure upstream (P1m) or downstream (P1m') of the fluid obstruction, - measuring a recovered pressure (P3m) at a recovered pressure location downstream of the fluid obstruction, - performing diagnostics based on parameters derived from the differential pressure (dP), the first static pressure (P1m, P1 m') and the measured recovered pressure (P3m).