Inferential Flow Meter Dynamic Sub-Window Pulsation Filtering
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Solution Overview
Problem
Inferential flow meters, such as turbine flow meters, face errors in viscosity calculation and flow rate measurement due to flow pulsations caused by events like submersible turbine pump operations or nozzle snaps, which result in instantaneous speed variations that are not accurately filtered out by existing methods.
Innovation Solution
A controller is used in conjunction with a pulser to determine fluid flow by dividing the flow into dynamic time sub-windows based on consistent pulse durations, allowing for the calculation of partial volumes within each sub-window and summing them to achieve an accurate total delivered volume, thereby filtering out spurious variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed time window is used to calculate flow rate by counting pulses, then the calculation is simple, but flow pulsations cause errors in viscosity and flow rate measurements
Solution Approach 1:
The fixed time window is divided into multiple dynamic sub-windows based on pulse duration thresholds. Each sub-window captures a consistent flow condition, and the flow rates from all sub-windows are summed to get the total flow. This segmentation allows the system to adapt to flow pulsations while maintaining computational simplicity.
2Ease of operation
If the measurement method filters out instantaneous speed variations, then calculation is simplified, but errors in viscosity calculation and flow rate occur
Solution Approach 1:
The measurement method transitions from a static fixed time window to a dynamic sub-window approach. The sub-windows are dynamically created based on pulse duration variations, allowing the system to adapt to changing flow conditions. This dynamic adaptation maintains measurement accuracy while keeping the calculation process straightforward through automated threshold-based segmentation.
3Device complexity
If a single time window is used for flow measurement, then the device is simple, but it cannot accurately measure flow during pulsations
Solution Approach 1:
The single time window is segmented into multiple dynamic sub-windows based on pulse duration analysis. Each sub-window represents a period of consistent instantaneous flow, and the results from all sub-windows are aggregated. This segmentation enables accurate measurement during pulsations without significantly increasing device complexity, as the segmentation is achieved through software-based pulse duration comparison.
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 accurate measurement of fluid flow even during pulsations, reducing errors in viscosity calculation and flow rate determination by capturing instantaneous flow rates within dynamic sub-windows and summing them over time.
Implementation Method 1
A detector is typically mounted to the housing to detect rotation of one or both of the rotors. For example, the detector may be a hall effect device or pickup coil that determines rotation based on changes in a magnetic field. The detector is associated with a 'pulser' that produces a series of pulses at a rate which is related to the flow rate of fluid through the meter.
Data Source
AI summary
An apparatus and method for measuring fluid flow comprising an inferential flow meter having a housing defining a fluid flow path. A pulser is operative to produce an output signal indicative of flow rate through the meter. The apparatus further includes a controller in electronic communication with the pulser so as to receive the output signal. Based on the output signal, the controller is operative to determine fluid flow in a plurality of dynamic time sub-windows corresponding to respective periods of substantially consistent instantaneous flow.