Thermal Block Assemblies for Low Thermal Non-Uniformity
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Solution Overview
Problem
Thermal non-uniformity (TNU) in thermal block assemblies for bioanalysis instrumentation remains a challenge, with existing designs experiencing significant temperature variations between samples, particularly due to decoupled thermal equilibria between the sample block and heat sink, leading to inefficiencies in thermal cycling.
Innovation Solution
A redesigned thermal block assembly with a heat sink and sample block configuration that optimizes thermal mass distribution and airflow, featuring a combined footprint of thermal electric devices matching the sample block and heat sink surfaces, and a transverse fan system for uniform air flow, reducing thermal gradients and achieving uniform heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional thermal block assembly design is used, then thermal cycling capability is provided, but thermal non-uniformity is significant with TNU exceeding 1.0 °C
Solution Approach 1:
The thermal block assembly is segmented into distinct functional zones: a sample block portion for sample containment, a heat sink portion with optimized thermal mass, and integrated thermal electric devices positioned at specific locations. This segmentation allows independent optimization of each zone's thermal properties to achieve uniform temperature distribution across the sample block.
Solution Approach 2:
The patent applies local quality by positioning thermal electric devices at specific locations rather than uniform distribution, and by providing different thermal masses in different regions of the heat sink. The thermal electric devices are strategically placed to compensate for local thermal gradients, particularly at the edges of the sample block where cooling effects are most pronounced.
2Productivity
If rapid thermal cycling is implemented, then throughput is enhanced, but thermal non-uniformity increases due to decoupled thermal equilibria
Solution Approach 1:
The patent merges the sample block and heat sink into an integrated assembly where thermal electric devices are positioned to simultaneously heat or cool both components. This unified thermal control system ensures that the sample block and heat sink remain thermally coupled during rapid cycling, preventing decoupled thermal equilibria and maintaining temperature uniformity even at high cycling speeds.
Solution Approach 2:
The integrated design of the thermal block assembly with strategically positioned thermal electric devices creates a feedback mechanism where temperature variations in the sample block are immediately compensated by the heat sink's thermal mass and the responsive thermal electric devices, maintaining thermal equilibrium during rapid cycling operations.
3Manufacturing precision
If edge heaters are added to counteract thermal gradients, then temperature uniformity improves, but device complexity increases
Solution Approach 1:
The thermal electric devices serve multiple functions: they provide primary thermal control for the sample block, compensate for edge cooling effects, and maintain thermal coupling between the sample block and heat sink. This multi-functionality eliminates the need for separate edge heater components while achieving temperature uniformity across the sample block.
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 achieves significantly lower thermal non-uniformity, with static and dynamic TNU between 0.05 °C to 0.25 °C, reducing cycle time and enhancing the precision and throughput of bioanalytical processes.
Implementation Method 1
a sample block, a heat sink, and thermal electric devices positioned between the sample block and the heat sink
Implementation Method 2
heat sink with a base plate and fins
Implementation Method 3
a transverse fan system for uniform air flow
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present teachings disclose various embodiments of a thermal block assembly having low thermal non-uniformity throughout the thermal block assembly. Accordingly, various embodiments of thermal block assemblies having such low thermal non-uniformity provide for desired performance of bioanalysis instrumentation utilizing such thermal block assemblies.