Coriolis Flowmeter Pressure Compensation
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Solution Overview
Problem
Existing Coriolis flowmeters face inaccuracies in mass flow rate measurements due to variations in manufacturing tolerances and conduit stiffness, leading to inaccuracies in predefined pressure compensation constants.
Innovation Solution
A method to determine a unique pressure coefficient value for each flowmeter by establishing a relationship between the flow calibration factor and pressure coefficient, allowing for individualized pressure compensation, which is applied to the flowmeter's calculations to improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a predefined pressure compensation constant is used for Coriolis flowmeters, then the device complexity is reduced and ease of manufacture is improved, but measurement precision deteriorates due to manufacturing tolerances and conduit stiffness variations
Solution Approach 1:
The patent applies preliminary action by determining and storing a unique pressure compensation coefficient for each flowmeter during the manufacturing process. This pre-determined coefficient accounts for individual variations in conduit stiffness and manufacturing tolerances, so that when the flowmeter is installed and used, accurate pressure compensation is already in place without requiring complex real-time adjustments or additional hardware.
Solution Approach 2:
The patent implements parameter changes by transitioning from a single predefined pressure compensation constant for all flowmeters of a model to individualized pressure compensation coefficients determined for each specific flowmeter. This parameter change accommodates variations in conduit stiffness and manufacturing tolerances, thereby improving measurement precision without significantly increasing device complexity.
2Measurement precision
If individualized pressure compensation is implemented for each flowmeter, then measurement precision is improved, but device complexity and manufacturing complexity increase
Solution Approach 1:
The patent applies self-service by enabling each flowmeter to determine its own unique pressure compensation coefficient during a simple calibration process. The system uses the flowmeter's existing components (conduits, drivers, and pickoffs) to measure time delay at different pressures and automatically calculates the appropriate compensation coefficient, eliminating the need for complex external calibration equipment or manual adjustment procedures.
Solution Approach 2:
The patent implements parameter changes by modifying the pressure compensation coefficient based on individual flowmeter characteristics measured during calibration. This approach allows each flowmeter to be optimized for its specific manufacturing variations while maintaining a straightforward calibration process that does not require complex procedures or additional hardware.
3Measurement precision
If manufacturing tolerances and conduit stiffness variations are accounted for, then measurement precision is improved, but the complexity of determining unique calibration parameters increases
Solution Approach 1:
The patent applies self-service by enabling the flowmeter to automatically determine its own unique calibration parameters (flow calibration factor and pressure compensation coefficient) through an internal calibration process. The system uses its existing measurement capabilities to characterize its own performance and generate the necessary compensation parameters, eliminating the need for complex external calibration equipment or manual adjustment procedures.
Solution Approach 2:
The patent implements feedback by using the flowmeter's own measurements of time delay at different pressures to determine its unique pressure compensation coefficient. The system measures the actual performance characteristics, feeds this information back into the calibration process, and adjusts the compensation parameters accordingly, creating a closed-loop system that automatically accounts for manufacturing variations.
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 more accurate mass flow rate measurements by accounting for specific flowmeter variations, enhancing the precision of fluid flow characteristics determination.
Implementation Method 1
An alternating current is passed to the drive coil for vibrating the conduit(s) at a desired flow tube amplitude and frequency
Implementation Method 2
the pickoffs can use the motion provided by the driver to induce a voltage
Implementation Method 3
As material begins to flow through the flowmeter, Coriolis forces cause each point along the conduit(s) to have a different phase
Data Source
AI summary
A method for calibrating a flowmeter (5) is provided. A relationship between a flow calibration factor and a pressure coefficient for a class of flowmeter is determined. A unique flow calibration factor is then determined for a flowmeter (5). A unique pressure coefficient for the flowmeter (5) is determined, and the unique pressure coefficient is applied to the flowmeter (5).