Fluid Flow Meter Viscosity Correction via Differential Pressure
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Solution Overview
Problem
Factory calibration of fluid flow meters does not account for viscosity changes in fluids, leading to inaccurate measurements when the viscosity of the fluid varies over time, such as due to product deterioration, resulting in under-feeding or over-feeding in applications like chemical dispensing.
Innovation Solution
A fluid flow meter with a controller that generates pulses based on the rotation of gears and measures differential pressure to determine an unknown volumetric flow rate, using stored correlations between pulse frequency, differential pressure, and known flow rates to adjust for viscosity changes, allowing for precise measurement adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If factory calibration is used for fluid flow meters, then the device complexity is reduced and ease of operation is improved, but measurement precision deteriorates when fluid viscosity varies
Solution Approach 1:
The patent applies parameter changes by measuring differential pressure across the flow meter, which changes with fluid viscosity. The system uses the differential pressure reading to select appropriate calibration data from multiple viscosity-specific calibration sets, thereby adapting the measurement parameters to match the actual fluid conditions and maintaining accuracy despite viscosity variations
Solution Approach 2:
The patent implements preliminary action by pre-storing multiple calibration data sets corresponding to different viscosity levels in the controller's memory. This allows the system to quickly retrieve and apply the appropriate calibration without real-time complex calculations, resolving the contradiction between measurement precision and device complexity
2Measurement precision
If viscosity correction is implemented, then measurement precision is improved, but device complexity increases due to additional sensors and processing
Solution Approach 1:
The patent applies universality by making the differential pressure sensor serve multiple functions: it characterizes fluid viscosity, selects appropriate calibration data, and enables accurate flow measurement across varying viscosity conditions. This multi-functionality reduces the need for separate viscosity measurement devices, thereby limiting the increase in device complexity while maintaining improved measurement precision
Solution Approach 2:
The patent uses differential pressure as an intermediary parameter that correlates with both fluid viscosity and flow rate. By measuring this intermediary parameter, the system can infer viscosity changes and apply appropriate corrections without requiring direct viscosity measurement, thus improving precision while minimizing additional system complexity
3Measurement precision
If multiple calibration data sets are stored for different viscosities, then measurement precision is improved, but loss of information increases due to larger data storage requirements
Solution Approach 1:
The patent applies segmentation by dividing the calibration data into multiple discrete viscosity-specific data sets stored in the controller's memory. Each data set corresponds to a specific viscosity range, allowing the system to efficiently store and retrieve only the relevant calibration information needed for accurate measurement, thereby improving precision while managing data storage requirements through organized segmentation
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 solution ensures accurate measurement of fluid flow rates by compensating for viscosity changes, improving measurement accuracy and preventing errors due to fluid viscosity variations, ensuring precise dispensing in industrial and pharmaceutical applications.
Implementation Method 1
A pressure sensor may be connected in parallel to the flow chamber and configured to measure the differential pressure across the flow chamber
Data Source
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AI summary
A fluid flow meter is provided that generates a pulsed output to account for viscosity variations. The fluid flow meter includes a controller with a data storage that can store correlations of fluid pressure, volumetric flow rate and pulse frequency for different viscosities, based on a calibration of the fluid flow meter. A pressure sensor can be connected in parallel to a flow chamber of the fluid flow meter for measuring the pressure across the flow chamber.