Stackable Crucible System for TGA Sample Capacity
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Solution Overview
Problem
Thermogravimetric analyzers (TGA) face limitations in increasing the number of samples that can be tested simultaneously within a given furnace capacity, leading to inefficiencies in sample analysis and extended weighing times.
Innovation Solution
The method involves using a double carousel system with upper and lower crucibles, where the upper crucible is stacked on the lower crucible, allowing for simultaneous analysis of multiple samples by determining tare weights, subtracting crucible weights to isolate sample weights, and maintaining furnace temperature until constant weights are achieved, thereby doubling the furnace capacity with minimal increase in weighing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single carousel system is used to hold crucibles, then the device complexity is low, but the number of samples that can be tested simultaneously is limited
Solution Approach 1:
The patent implements nesting by placing an upper carousel within the furnace chamber and allowing it to be lowered onto the lower carousel. The upper carousel holds additional crucibles that can be stacked on top of crucibles in the lower carousel, effectively nesting two levels of sample holding capacity within the same furnace structure. This increases the number of simultaneous samples from one level to two levels without proportionally increasing overall device complexity.
2Productivity
If multiple crucibles are weighed separately, then the measurement precision is maintained, but the weighing time increases
Solution Approach 1:
The patent merges the weighing process by allowing the upper carousel with its crucibles to be weighed together with the lower carousel in a single weighing operation. The balance can simultaneously measure the combined weight of both carousels, and the system automatically calculates individual sample weights by subtracting known tare weights. This combining approach doubles the number of samples weighed per operation without requiring separate weighing time for each crucible.
Solution Approach 2:
The system performs preliminary actions by pre-determining and storing the tare weights of individual crucibles and carousels before the actual sample weighing. This allows the balance to directly calculate sample weights by simple subtraction during the weighing operation, eliminating the need for complex multi-step weighing procedures and reducing total weighing time while maintaining precision.
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 effectively doubles the sample capacity of the TGA while maintaining efficient weighing times, allowing for precise and automated analysis of moisture and ash in multiple samples with reduced analysis time and increased productivity.
Implementation Method 1
The furnace is heated to a target temperature
Implementation Method 2
A balance is used to measure the weight of the crucibles with the samples
Implementation Method 3
The upper crucible is stacked on the lower crucible
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
A system is provided for analyzing a plurality of samples in a furnace (310). The system includes an upper carousel (210) including at least one opening (212) adapted to engage at least one upper crucible (110). The system also includes a lower carousel (220) including at least one opening (212) adapted to engage at least one lower crucible (120). The system includes a scale (240) adapted to receive a lower crucible (120) and weigh the lower crucible (120). The scale (240) is further adapted to receive a combination of an upper crucible (110) stacked on the lower crucible (120) and weigh the combination. The system also includes means for moving the upper carousel (210) and the lower carousel (220) relative to each other and relative to the scale (240) so that the scale (240) selectively receives the lower crucible (120) and the combination of the upper crucible (110) stacked on the lower crucible. A method of testing samples in a furnace (310) is provided.