Optical Tube-Position Sensing for Coriolis Flow Meters
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Solution Overview
Problem
Current flow measurement technologies in high-performance liquid chromatography (HPLC) face challenges in accurately measuring low flow rates due to thermal expansion, fluid compressibility, and the need for complex pump designs, while Coriolis mass flow meters are limited by heat generation and accuracy issues in thin tubes.
Innovation Solution
An assembly comprising a source of electromagnetic radiation, a detector, and a tube assembly that uses optical elements to measure tube position without direct contact, reducing heat transfer and improving accuracy by using optical fibers or lenses to transmit and receive electromagnetic radiation, allowing for precise mass and volume flow rate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal mass flow meters are used for flow measurements in HPLC applications, then flow rate can be measured, but the measurement depends on fluid characteristics requiring careful calibration
Solution Approach 1:
The patent replaces thermal mass flow meters with a Coriolis mass flow meter that uses electromagnetic actuation and detection. The drive coil generates electromagnetic forces to oscillate the measurement tube, and the detection coil measures the oscillation signal, eliminating the need for thermal-based measurements that require fluid-specific calibration.
Solution Approach 2:
The patent changes the measurement principle from thermal parameters to electromagnetic parameters. By using electromagnetic actuation and detection, the system measures mass flow directly through Coriolis forces without being influenced by fluid thermal characteristics, thereby eliminating calibration requirements for different fluids.
2Measurement precision
If ultrasonic flow meters are used for flow measurements in HPLC applications, then flow rate can be measured, but the measurement depends on the characteristics of the fluid requiring careful calibration
Solution Approach 1:
The patent replaces ultrasonic flow meters with a Coriolis mass flow meter using electromagnetic measurement. The electromagnetic system directly measures mass flow through tube oscillation without relying on ultrasonic wave propagation through the fluid, eliminating fluid characteristic dependencies.
3Ease of operation
If piston movement is measured to infer flow rate, then flow control can be achieved, but high demands on tightness of all involved components are required
Solution Approach 1:
The patent replaces mechanical piston-based flow control with electromagnetic flow measurement. The Coriolis flow meter directly measures actual mass flow through electromagnetic detection of tube oscillation, providing feedback for flow control without relying on mechanical seal tightness.
4Measurement precision
If piston displacement is used to infer flow rate, then flow measurement can be obtained, but compressibility and thermal expansion of the fluid require compensation
Solution Approach 1:
The patent replaces volumetric displacement measurement with direct mass flow measurement using Coriolis forces. Since mass flow is measured directly through tube oscillation characteristics, no compensation for fluid compressibility or thermal expansion is needed.
Solution Approach 2:
The patent changes from measuring volumetric parameters (piston displacement) to measuring mass parameters (Coriolis forces). This parameter change eliminates the need to account for fluid compressibility and thermal expansion effects.
5Measurement precision
If optical elements are used to measure tube position without direct contact, then heat transfer is reduced and accuracy is improved, but device complexity increases
Solution Approach 1:
The patent introduces optical elements (light source, optical fiber, detector) as intermediaries to measure tube position indirectly through light transmission. The optical fiber transmits light to and from the measurement tube without physical contact, reducing heat transfer while enabling precise position detection.
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 provides accurate mass and volume flow rate measurements over a wide range with high precision, reducing heat-induced errors and maintaining stable retention times, suitable for HPLC applications with fluid pressures up to 1500 bar and flow rates from 50 μl/min to 5 ml/min.
Implementation Method 1
a source (1) of electromagnetic radiation
Implementation Method 2
using optical fibers or lenses to transmit and receive electromagnetic radiation
Implementation Method 3
a detector assembly (2) comprising a detector (21) for electromagnetic radiation
Implementation Method 4
A Coriolis mass flow meter may also be referred to as Coriolis mass flow meter
Data Source
AI summary
The present invention relates to an assembly comprising a source of electromagnetic radiation, a detector assembly comprising a detector for electromagnetic radiation, a tube assembly comprising a portion of a tube, and a source optical element configured to transmit electromagnetic radiation received at a receiving end to an emitting end of the source optical element. The detector assembly comprises a detector assembly receiving end positioned to receive at least a part of the electromagnetic radiation from the source, wherein at least part of the electromagnetic radiation received at the detector assembly receiving end is received by the detector. A first direction (x) is defined by a light path between the emitting end of the source optical element and the detector assembly receiving end, wherein the tube assembly is positioned between the emitting end and the detector assembly receiving end in the first direction (x), wherein the tube assembly is movable to change its position, and wherein an amount of electromagnetic radiation received by the detector depends on the position of the tube assembly. The present invention further relates to a Coriolis flow meter system, a corresponding method and a solvent delivery system.