Thermal Conductivity Measurement Using Single-Sensor Plastic Plate
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Solution Overview
Problem
Existing methods for determining thermal conductivity are complex, costly, and not suitable for measuring samples under pressure, as they require multiple temperature sensors and reference plates that are fragile and prone to heat loss, making them inefficient for geothermal investigations.
Innovation Solution
A method that measures only one temperature at the center of a comparison sample plate between two heating plates, allowing for accurate thermal conductivity determination with minimal structural effort, using a plastic comparison sample plate with embedded filling materials to match the thermal conductivity of the sample and enabling pressure application, thus reducing edge effects and heat transfer issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature sensors and reference plates are used to determine thermal conductivity, then measurement accuracy can be improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts only the essential measurement function by using a single temperature sensor in the center of the sample, eliminating the need for multiple sensors and complex reference plate arrangements. This simplifies the device structure while maintaining measurement capability by focusing on the most critical temperature point for thermal conductivity determination.
Solution Approach 2:
The heating plates serve multiple functions: they provide controlled thermal boundaries for measurement, apply uniform pressure to the sample, and eliminate the need for separate reference plates. This multi-functionality reduces device complexity while maintaining measurement accuracy through the standardized measurement protocol.
2Measurement precision
If quartz glass reference plates are used, then thermal conductivity measurement can be performed, but the plates are fragile and cannot withstand pressure
Solution Approach 1:
The patent replaces fragile quartz glass reference plates with durable plastic plates that can withstand pressure. While plastic has different thermal conductivity properties, the measurement method compensates for this by using controlled heating plates and a standardized calculation approach, making the reference plate material less critical and allowing use of pressure-resistant, cost-effective materials.
3Loss of energy
If additional heating devices with complex electronic controls are arranged around the test sample, then heat loss prevention improves, but device complexity and cost increase
Solution Approach 1:
The patent uses the sample chambers and heating plates themselves to define the measurement geometry and control heat flow, eliminating the need for additional external heating devices. The system serves its own insulation function through proper thermal boundary definition, reducing device complexity while maintaining energy efficiency.
4Ease of manufacture
If copper plates are arranged adjacent to quartz glass plates, then temperature sensor installation is simplified, but structural size increases and measurement accuracy is reduced
Solution Approach 1:
The patent removes the intermediate copper plate layer entirely, installing the temperature sensor directly in the plastic reference plate or sample chamber. This eliminates the additional heat transfer interface that would reduce measurement accuracy while maintaining ease of manufacture through direct sensor placement in the pressure-resistant plastic material.
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 method allows for quick and precise thermal conductivity measurement with reduced design complexity and accuracy, capable of simulating deep-earth conditions without the need for additional sensors or fragile materials, enhancing measurement precision and applicability to pressurized environments.
Implementation Method 1
the thermal conductivity of a measurement sample can be determined... Thermal conductivity is the property of a sample material to transport thermal energy in the form of heat through the measurement sample
Implementation Method 2
temperature gradients are determined in the two reference plates and the thermal conductivity of the measurement sample arranged between the reference plates is calculated from this
Data Source
Figure 1~2
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AI summary
The method involves arranging measuring probe chamber (1) and plastic/ceramic/graphite material made sample plate (2) in series between heating plates (6,7). The temperatures of heating plates are controlled independently. A temperature sensor is arranged at predefined distance from surface of sample plate, so as to measure the temperature of sample plate. The thermal conductivity and diffusivity of measuring sample is determined as a function of predefined distance between temperature sensor and sample plate, and temperatures of heating plate and sample plate. An independent claim is included for device for determining thermal conductivity and diffusivity of measuring sample.