Capillary Channel Viscosity Measurement Without Pumps
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Solution Overview
Problem
Existing methods for measuring fluid properties, such as viscosity, often require large fluid volumes and are susceptible to temperature variations, making them impractical for small sample volumes and space-constrained applications like lab-on-a-chip devices, especially when temperature control is necessary.
Innovation Solution
A device and method using a capillary channel with sensors to measure fluid flow rate and viscosity without pumps, employing capillary forces and thermal control to maintain accurate measurements across small sample volumes, utilizing CMOS technology and integrated thermal sensors to monitor and regulate temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional fluid property measurement methods are used, then measurement accuracy can be maintained, but large fluid volumes are required
Solution Approach 1:
The patent replaces conventional mechanical measurement systems (rotational viscometers, falling ball devices) with a microfluidic capillary channel system that uses capillary forces and pressure gradients to drive fluid flow. Sensors detect fluid position and flow rate through the capillary channel, enabling viscosity measurement of nanoliter-scale samples without requiring large fluid volumes or complex mechanical measurement apparatus.
2Device complexity
If fluid property measurement is performed without temperature control, then device complexity is reduced, but measurement accuracy deteriorates due to temperature variations
Solution Approach 1:
The patent incorporates temperature as a controllable parameter by integrating thermal sensors and thermal control elements directly into the microfluidic device. The system monitors temperature in the capillary channel and adjusts heating or cooling to maintain constant temperature conditions during viscosity measurements, ensuring measurement accuracy while working within space-constrained lab-on-a-chip environments.
3Area of stationary object
If pumps and injection mechanisms are used for fluid delivery, then fluid flow control is improved, but device space requirements increase
Solution Approach 1:
The patent employs capillary forces arising from surface tension and wetting effects to automatically drive fluid through the capillary channel without requiring external pumps or injection mechanisms. The microfluidic system is designed with appropriate hydrophobic/hydrophilic surface treatments and pressure gradients that enable spontaneous fluid flow and positioning, eliminating the need for bulky mechanical fluid handling components and reducing overall device footprint.
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
Enables precise measurement of fluid properties in nano- or microliter volumes with reduced temperature variability, optimizing space usage in lab-on-a-chip devices by eliminating the need for fluid pumps and injection mechanisms.
Implementation Method 1
employing capillary forces
Implementation Method 2
a thermal sensor and a thermal element may be integrated into the device. The thermal sensor may be arranged to determine a temperature of an environment surrounding the capillary channel
Implementation Method 3
The thermal element may be arranged to heat or cool the environment surrounding the capillary channel
Data Source
AI summary
The viscosity of a fluid may be determined using a flow rate determination. The flow rate may be determined based on fluid presence determinations within a capillary channel. Also, a temperature of an environment surrounding a capillary channel may be determined and signals may be transmitted to a thermal element responsive to the determined temperature.