Multi-capillary Viscometer Flow Reversal Valve
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Solution Overview
Problem
Multi-capillary viscometers face a limitation known as the breakthrough peak, which is an unwanted instrument response causing delayed measurement due to the discharge of sample fluid from the delay volume component through the reference capillary, leading to prolonged analysis times and interference in subsequent measurements.
Innovation Solution
The introduction of a fluid path diverter valve that reverses the flow direction through the reference capillary after the measurement, eliminating the breakthrough peak by flushing out the sample solution and allowing for quicker preparation of the system for the next sample analysis, and the use of additional delay volume components and fluid diverting components to manage solvent flow and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a delay volume component is used to maintain reference flow during measurement, then viscosity measurement accuracy is improved, but breakthrough peak occurs causing prolonged analysis time
Solution Approach 1:
The delay volume is divided into two separate delay volume components (first delay volume and second delay volume) positioned at different locations in the circuit. This segmentation allows the first delay volume to maintain reference flow during measurement while the second delay volume handles sample discharge, preventing breakthrough peak from reaching the detector and eliminating prolonged analysis time.
Solution Approach 2:
A fluid diverting component is introduced as an intermediary device that selectively directs fluid flow between different pathways. During measurement, it ensures reference flow passes through the delay volume for accurate viscosity detection. After measurement, it redirects and flushes sample solution from the delay volume, preventing breakthrough peak and enabling rapid preparation for the next sample.
2Stability of the object's composition
If sample solution remains in delay volume after measurement, then baseline conditions are maintained, but breakthrough peak interferes with subsequent measurements
Solution Approach 1:
The system implements periodic flushing action using the fluid diverting component to periodically clear sample solution from the delay volume after each measurement. This periodic intervention removes accumulated sample that would otherwise cause breakthrough peak, while maintaining stable baseline conditions during the measurement phase when the diverting component directs normal reference flow.
Solution Approach 2:
The fluid diverting component enables discarding of sample solution from the delay volume after measurement by redirecting it to waste. This discarding action prevents breakthrough peak interference with subsequent measurements. The delay volume is then recovered and refilled with fresh reference solvent, restoring baseline conditions for the next measurement cycle.
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 solution significantly reduces the time required for subsequent analyses by eliminating the breakthrough peak, enabling faster and more accurate viscosity measurements by maintaining baseline conditions and minimizing disturbance to the measurement circuit.
Implementation Method 1
a change in fluid pressure caused by the viscosity of the sample solution flowing through the capillary
Implementation Method 2
a transducer operable for sensing a fluid pressure difference across the capillary and producing a signal substantially corresponding to the pressure drop
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
This apparatus and method relates to the improved sensing of fluid differential pressures. The apparatus and method can be applied in multi-capillary solution viscometers and gel permeation chromatography systems used in the characterization of polymers. A valve is used to alter a flow path in a measurement circuit to reduce or eliminate an undesired fluid output and to accelerate the regeneration of the fluid for analysis of subsequent samples. The apparatus and method can be usefully applied to all instruments and systems comprising viscometers having two or more capillaries.