Rimming Flow Viscosity Measurement via Torque and Optical Thickness
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Solution Overview
Problem
Existing methods for measuring viscoelastic properties of liquids, such as cone and plate viscometers, face challenges including sensitive torque measurements, friction issues, temperature control difficulties, and flow instabilities, especially for larger samples and liquids with impurities, limiting their practicality and accuracy.
Innovation Solution
A mechanical device measuring torque applied to a horizontal rotating cylinder to determine viscoelastic properties of liquids through rimming flow, allowing for more accurate and sensitive measurements across a range of frequencies and temperatures, including larger samples and non-transparent liquids, by relating torque to dissipation and using optical methods for temperature control and additional parameter measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cone and plate viscometers are used to measure viscoelastic properties, then measurement frequency range and sample volume requirements are improved, but torque measurement sensitivity, friction control, and temperature stability deteriorate
Solution Approach 1:
The patent replaces the mechanical oscillating torque measurement system of cone and plate viscometers with an optical measurement system. The free surface shape of the rimming liquid is measured using optical methods (light absorption or reflection), eliminating the need for sensitive mechanical torque sensors and their associated friction and stability problems.
Solution Approach 2:
The patent introduces the free surface shape of the liquid as an intermediary parameter. Instead of measuring torque directly, the system measures the shape of the liquid's free surface during rimming flow, which indirectly reflects the viscoelastic properties. This intermediary measurement approach avoids the direct mechanical contact and friction issues.
2Quantity of substance
If cone and plate viscometers are used, then sample volume is reduced, but flow stability and temperature control worsen
Solution Approach 1:
The patent utilizes dynamic rimming flow in a rotating horizontal cylinder instead of static or oscillating small-gap configurations. The liquid flows along the inner wall of the rotating cylinder, creating a stable yet dynamic flow regime that is less sensitive to temperature variations and more suitable for larger sample volumes.
3Measurement precision
If optical absorption method is used to measure liquid thickness, then measurement accuracy is improved, but device complexity and operational difficulty worsen
Solution Approach 1:
The patent inverts the traditional optical measurement approach by placing the light source inside the rotating cylinder with the liquid and detecting light transmission from the outside, or vice versa. This inversion simplifies the optical system by eliminating the need for complex rotating component signal transmission and allows for more straightforward temperature control of the liquid sample.
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 approach enhances measurement accuracy, sensitivity, and temperature control, enabling the characterization of a wider range of liquids, including those with impurities, and allows for higher sensitivity and robust equipment design, facilitating detailed flow field studies and verification of evaluation models.
Implementation Method 1
The cylinder is rotated at a sufficient speed such that the liquid adheres to the inner wall of the cylinder forming a circular or near-circular inner free surface
Implementation Method 2
means for measuring the applied torque
Implementation Method 3
The light was passed from within the cylinder onto a photodiode glued on the outside of a transparent horizontal rotatable cylinder. The measurement resulted from the thickness of the liquid over the circumference of the cylinder.
Data Source
AI summary
The invention discloses a device for viscosity or viscoelasticity measurement comprising: a horizontal rotatable cylinder-shaped section for receiving a liquid whose viscosity or viscoelasticity is to be measured, and a torque meter for measuring the torque from said liquid while in rotation. It also discloses a method of measuring viscosity or viscoelasticity of a liquid comprising the following steps: placing a liquid into a horizontal rotatable cylinder-shaped section, said liquid partially filling said structure; rotating said structure at a speed such that a quasi-cylindrical inner free surface of the liquid is obtained; determining the torque from said liquid when rotating said partially filled structure and calculating the viscosity or viscoelasticity of the liquid from the torque determined in the previous step.