Micro-Well Thermal Control Using Liquid Convection and Thermoelectrics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal control systems for sample-containing assay trays in PCR and bDNA testing face limitations in heat transfer efficiency due to reliance on air convection and large thermal components, which hinder uniform and rapid heating and cooling processes.
Innovation Solution
An active thermal control subsystem using a fluidic circuit with a pump, heat exchange device, and thermo-electric devices, coupled with heat spreaders, facilitates heat transfer through liquid convection, enabling bi-directional heat transfer and precise temperature control of sample-containing trays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air convection is used for heat transfer, then the thermal component size can be larger, but heat transfer efficiency and uniformity deteriorate
Solution Approach 1:
The patent replaces air convection with liquid convection by introducing a fluidic circuit that circulates heat transfer liquid through channels in the thermal control subsystem. This hydraulic approach enables more efficient heat transfer while allowing for a more compact design, as liquids have higher heat capacity and thermal conductivity compared to air.
Solution Approach 2:
The patent introduces a heat transfer liquid as an intermediary medium between the heat source/sink and the sample-containing vessels. This liquid mediator facilitates superior thermal coupling and heat distribution compared to direct air convection, enabling both higher efficiency and more uniform temperature control.
2Measurement precision
If conventional heating elements are used, then the system structure is simpler, but temperature uniformity and control precision deteriorate
Solution Approach 1:
The patent divides the thermal control system into multiple independent heating and cooling zones, each controlled by separate thermo-electric devices. This segmentation allows for precise local temperature control across different regions of the sample tray, achieving uniform temperature distribution while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent employs thermo-electric devices that can rapidly change temperature parameters in response to control signals. These devices allow bidirectional heat transfer (heating and cooling) by changing the electrical parameter direction, enabling precise temperature control with rapid response times and high precision without requiring complex mechanical adjustments.
3Speed
If rapid heating and cooling are required, then thermal response speed improves, but thermal gradients and non-uniformity increase
Solution Approach 1:
The patent implements continuous circulation of heat transfer liquid through the fluidic circuit, ensuring constant thermal contact between the liquid and the sample-containing vessels. This continuous action maintains uniform temperature distribution during rapid heating and cooling cycles, preventing thermal gradients while achieving high thermal response speeds through the efficient heat transfer properties of the liquid medium.
Solution Approach 2:
The heat transfer liquid serves multiple functions simultaneously: it acts as a heating medium when warmed, a cooling medium when cooled, and a uniforming agent that distributes thermal energy evenly across all sample vessels. This multi-functionality enables rapid temperature changes while maintaining temperature uniformity throughout the system.
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 achieves uniform temperature maintenance within ±0.5°C across multiple sample-containing vessels, with rapid temperature changes of up to 10°C/minute, enhancing thermal control efficiency and compactness while minimizing thermal gradients.
Implementation Method 1
a liquid heat-transferring concept that transfers heat by liquid convection rather than by air convection
Implementation Method 2
heat transfer for thermo-electric devices and/or heating elements is accomplished by conduction
Implementation Method 3
Current transmitted to the thermo-electric device(s) is controlled. Depending on the voltage at each junction, heat can be transferred bi-directionally
Data Source
AI summary
Devices and systems for active thermal control of sample holding devices for bDNA testing, polymerase chain reaction testing, chemiluminescent immuno-assay testing, and so forth. The thermal control subsystem includes a fluidic circuit, first and second heater assemblies, a centrifugal pump, and a heat exchange device. The first and second heater assemblies include a heat removal device and a controllable thermo-electric device. One or both of the heater assemblies can include a heat spreader. A controller actively controls the pump, the heat removal device, and the thermo-electric devices, to thermally-control sample-containing vessels retained in the holding device.