Flow Meter Assembly Using Pressure-Temperature Detection for Two-Phase Flow
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Solution Overview
Problem
Current cryogenic fluid dispensing systems face challenges in accurately measuring flow due to two-phase flow conditions, which can lead to metering errors, and existing solutions like phase separators and optical sensors are bulky, costly, or require complex calibration.
Innovation Solution
A flow meter assembly comprising a differential pressure transmitter, pressure transmitter, temperature transmitter, and controller that compares discharge pressure to saturation pressure to detect subcooling or two-phase flow, ensuring accurate metering by preventing vapor inclusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase separators are used to detect two-phase flow, then two-phase flow detection capability is improved, but device complexity and size increase
Solution Approach 1:
The patent extracts the two-phase flow detection function from complex mechanical phase separators and implements it through a simplified electronic system using pressure and temperature sensors with a controller that calculates vapor quality, thereby reducing device complexity while maintaining detection capability
Solution Approach 2:
The patent replaces the mechanical phase separator system with an electronic detection system using pressure transducers, temperature sensors, and a microcontroller that computes vapor quality based on thermodynamic relationships, eliminating bulky mechanical components
2Measurement precision
If optical sensors are used to detect vapor content, then two-phase flow detection accuracy is improved, but cost and calibration complexity increase
Solution Approach 1:
The patent substitutes optical sensors with pressure and temperature sensors combined with thermodynamic calculations, eliminating the need for complex optical alignment and calibration procedures while achieving equivalent or superior measurement accuracy
Solution Approach 2:
The patent uses indirect measurement by copying the thermodynamic relationship between pressure, temperature, and vapor quality, allowing accurate vapor content determination through readily available pressure and temperature sensors without direct optical measurement
3Productivity
If two-phase flow occurs, then flow measurement continues, but measurement accuracy deteriorates due to gas displacement
Solution Approach 1:
The patent implements continuous feedback by monitoring pressure and temperature to calculate vapor quality in real-time, allowing the system to detect two-phase conditions and adjust or halt metering to maintain accuracy while ensuring continuous flow monitoring capability
Solution Approach 2:
The patent performs preliminary detection of two-phase flow conditions using pressure and temperature measurements before significant vapor displacement occurs, allowing preventive action to be taken to maintain measurement accuracy
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 system effectively manages two-phase flow by ensuring liquid remains in the liquid state, preventing metering errors and maintaining accurate fluid measurement.
Implementation Method 1
a differential pressure transmitter
Implementation Method 2
a pressure transmitter
Implementation Method 3
a temperature transmitter
Implementation Method 4
compare a discharge pressure from the pressure transmitter to a saturation pressure determined using a temperature from the temperature transmitter to determine if there is subcooling or two-phase flow
Data Source
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AI summary
A flow meter assembly for a dispensing line includes a differential pressure transmitter, a pressure transmitter, a temperature transmitter and a controller in communication with each transmitter. The controller is configured to use data collected from the transmitters to determine if there is subcooling or two-phase flow of a fluid flowing through the dispensing line and to meter fluid flowing through the dispensing line if there is subcooling or no two-phase flow.