Subsea Chemical Agent Injection Bidirectional Flow Measurement
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Solution Overview
Problem
Inaccurate measurement of chemical agent flow rates in subsea injection devices due to incorrect installation direction and variable needle valve openings, leading to increased installation costs and operational inefficiencies.
Innovation Solution
A forward and reverse bidirectional flow rate measurement method for subsea chemical agent injection devices, utilizing a device body with a flow channel, pressure reduction member, and needle valve assembly, where differential pressures and needle valve openings are calibrated to establish relationships between flow rates and pressures, enabling real-time flow rate calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the subsea agent injection device is calibrated based on a default forward flow direction, then the forward flow rate measurement is accurate, but the device cannot accurately measure reverse flow rates when installed incorrectly
Solution Approach 1:
The patent applies universality by calibrating the device to handle both forward and reverse flow directions. The calibration process measures differential pressures for both flow directions and establishes separate calibration curves (QA for forward flow, QB for reverse flow), enabling the single device to accurately measure flow rates regardless of installation orientation.
Solution Approach 2:
The patent changes the calibration parameters to accommodate bidirectional measurement. By performing separate calibration procedures for forward and reverse flows, the device obtains direction-specific calibration coefficients and differential pressure relationships, allowing accurate measurement across different flow directions without requiring separate devices.
2Ease of operation
If a needle valve is introduced to control flow stability, then flow rate control is improved, but the flow rate parameters change with different valve openings making fixed parameter measurement impossible
Solution Approach 1:
The patent applies feedback by measuring the actual differential pressure across the needle valve assembly and using this measurement to determine the flow rate through calibrated relationships. The system continuously monitors differential pressure and translates it to flow rate using pre-established calibration curves, providing accurate real-time measurement despite variable valve openings.
Solution Approach 2:
The patent addresses the variable parameter issue by establishing separate calibration relationships for different operating conditions. The calibration process captures how differential pressure relates to flow rate at various needle valve openings, creating a mapping that allows accurate flow rate determination regardless of the specific valve position during operation.
3Reliability
If incorrect installation direction occurs, then the device requires pausing injection and reinstallation, but this increases installation costs and affects operational efficiency
Solution Approach 1:
The patent makes the device universal by enabling it to accurately measure both forward and reverse flows. This bidirectional calibration capability allows the device to function correctly regardless of installation direction, eliminating the need to pause injection operations for reinstallation and maintaining operational efficiency while ensuring reliable flow measurement.
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
Accurately measures forward and reverse flow rates in real-time, reducing installation errors and improving operational efficiency by directly fitting relationships between flow rate, differential pressure, and needle valve opening.
Implementation Method 1
an orifice plate and a flow channel groove can reduce a pressure of the high-pressure agent flowing through the device
Implementation Method 2
synchronously obtaining first differential pressures DP1 before and after the chemical agent flows through the pressure reduction member, and second differential pressures DP2 before and after the chemical agent flows through the needle valve assembly
Data Source
AI summary
A forward and reverse bidirectional flow rate measurement method for a subsea chemical agent injection device is provided. The device includes a device body, a flow channel is formed inside the device body, the device body includes an agent input connector, a pressure reduction member, a needle valve assembly, and an agent output connector that are sequentially communicated through the flow channel; and the method is implemented by: calibrating forward and reverse flow of agents at different openings and flow rates, then obtaining differential pressures before and after the agents flow through the needle value assembly; fitting relationships between the flow rates and the differential pressures at different openings to obtain a plurality of arrays of opening-flow coefficients; then fitting relationships between the flow coefficients and the needle valve openings to establish a formula for the flow rate and the opening-differential pressure, and finally performing the measurement in real time.