Flow Rate Measurement Using Detectable Substance Transit
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Solution Overview
Problem
Existing chromatography systems face challenges in accurately measuring fluidic flow rates due to dependence on fluid properties, pressure changes, and multiple flow paths, leading to inaccurate delay time estimation and incomplete recovery of compounds.
Innovation Solution
A flow rate measurement apparatus that introduces a detectable substance, such as a gas bubble, into the fluid stream and uses detectors to calculate the volumetric flow rate based on the time interval between detections and the known volume of the fluidic path, independent of fluid properties, allowing for accurate delay time estimation and enhanced compound recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow meters (velocimeters, laminar flow meters, thermal flow meters) are used to measure fluidic flow rate, then flow rate measurement is achieved, but the device requires knowledge of fluid properties (specific gravity, viscosity, specific heat) and recalibration when fluid type changes
Solution Approach 1:
The patent replaces conventional mechanical/thermal flow meters with an optical detection system. A detectable substance (bubble or particle) is injected into the fluid stream, and its transit time between two detection points is measured optically. This substitution eliminates dependence on fluid properties like viscosity and specific heat, as the measurement is based on tracking a physical marker rather than measuring fluid dynamics or thermal properties directly.
Solution Approach 2:
The patent introduces a detectable substance (bubble or particle) as an intermediary carrier for measurement. This intermediary is injected into the fluid stream and tracked by detectors. The substance serves as a mediator that allows flow rate measurement without directly interacting with or requiring knowledge of the fluid's physical properties, thereby enabling universal applicability across different fluid types.
2Measurement precision
If pump flow rate is used to estimate fluid flow rate at fraction collector, then flow rate estimation is achieved, but pressure drop and temperature changes cause fluid expansion/contraction leading to inaccurate delay time estimation
Solution Approach 1:
The patent performs preliminary measurement of the actual fluid flow rate at the fraction collector inlet by tracking the detectable substance through the system. This preliminary action captures the real flow conditions including effects of pressure drop and temperature changes, allowing accurate delay time estimation before fraction collection begins, rather than relying on pump settings that may not reflect actual downstream conditions.
Solution Approach 2:
The system uses feedback from actual flow measurements (obtained by tracking the detectable substance) to adjust and refine delay time calculations. The measured flow rate at the fraction collector inlet feeds back into the control system, enabling real-time correction of delay time estimates and ensuring accurate fraction collection even when flow conditions vary from pump settings.
3Measurement precision
If multiple detectors are used to measure flow rate by tracking detectable substance, then accurate volumetric flow rate measurement is achieved, but additional device components and calibration steps are required
Solution Approach 1:
The patent designs the detection system to be multi-functional: the same detectors and tracking methodology can measure flow rate at different positions in the system, detect various types of detectable substances (bubbles or particles), and provide both flow rate measurement and delay time calculation. This universal approach reduces the need for separate specialized devices for each measurement task.
Solution Approach 2:
The system uses the fluid stream itself and naturally occurring or easily introduced detectable substances as the measurement probe. The fluid carries the detectable substance passively, and the detectors automatically track it without requiring complex external actuation. The system essentially measures itself using the flow medium as both carrier and signal source.
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 method enables accurate measurement of fluid flow rates with minimal dependence on fluid properties, ensuring complete recovery of compounds by providing precise delay time estimation, even under changing conditions.
Implementation Method 1
A first detector is disposed in a path of the flow of fluid containing the detectable substance. The first detector produces a signal in response to detecting the substance in the flow of fluid.
Implementation Method 2
A second detector is disposed downstream from the first detector in the path of the flow of fluid containing the detectable substance. The second detector produces a signal in response to detecting the substance in the flow of fluid.
Implementation Method 3
The data system computes a volumetric flow rate of the flow of fluid based on a time interval between the signals and a volume of the path between the first and second detectors.
Data Source
AI summary
Apparatus and method measure the flow rate of fluid for use in calibrating fraction collection in a chromatography system. An injector inserts a detectable substance into a flow of fluid. A first detector, disposed in a path of the flow of liquid with the substance, produces a signal in response to detecting the substance in the flow of fluid. A second detector, disposed downstream from the first detector in the path of the flow of fluid with the substance, produces a signal in response to detecting the substance in the flow of fluid. A computing system receives each signal produced by the first and second detectors upon detecting the substance in the flow of fluid, and computes a volumetric flow rate of the flow of fluid based on a time interval between the signals and a volume of the path between the first and second detectors.