Temperature Exposure Indicator Using Fracture Capsules and Color-Changing Pigments
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Solution Overview
Problem
Current methods for indicating temperature changes, such as freeze-thaw transitions in food and medical storage, are either impractical or excessively costly, particularly when used on a large scale, and do not provide clear, reliable indicators for temperature exposure beyond freezing.
Innovation Solution
A system employing salts of weak acid-strong base or strong acid-weak base compounds as reactants within microcapsules that fracture upon freezing or melting, producing a brilliant pigment indicating temperature exposure, which can be used as a low or high temperature indicator, and can be adapted for dual or time-temperature monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If maximum-minimum thermometers are used to indicate temperature range, then temperature monitoring capability is improved, but device complexity and cost increase prohibitively
Solution Approach 1:
The patent employs color-changing indicators that transition between different colors based on temperature exposure. The indicator contains a pigment that changes color when exposed to temperatures above or below specific thresholds, providing simple visual temperature monitoring without complex mechanical or electronic components.
Solution Approach 2:
The invention uses inexpensive, disposable indicator strips or tags that can be attached to items temporarily. These single-use indicators provide adequate temperature monitoring for the duration needed, then are discarded, avoiding the need for expensive, reusable equipment like maximum-minimum thermometers.
2Loss of information
If freeze-thaw indicators using dyes are used, then temperature indication is provided, but clarity of indication and manufacturing cost are compromised
Solution Approach 1:
The patent uses pigments instead of dyes to achieve color changes. Pigments provide more brilliant, clearer color transitions that are easier to distinguish visually. The pigment-based indicator shows distinct color changes at temperature thresholds, improving reliability and reducing error chances compared to dye-based systems.
3Measurement precision
If known freeze-thaw indicator devices are used, then temperature monitoring is achieved, but device size and manufacturing cost increase
Solution Approach 1:
The patent divides the temperature monitoring function into small, modular indicator elements that can be attached to individual items. Each indicator is a compact strip or tag containing the temperature-sensitive pigment, allowing distributed monitoring across multiple items without requiring large centralized equipment.
Solution Approach 2:
The use of temperature-sensitive pigments that change color at specific thresholds enables compact indicator design. The chemical property of the pigment provides the monitoring function within a small physical footprint, eliminating the need for larger mechanical or electronic components found in other devices.
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 provides a cost-effective, reliable, and clear indication of temperature exposure, allowing for the monitoring of items across various temperature thresholds, enhancing safety and efficiency in food and medical storage by ensuring accurate tracking of temperature history without the need for extensive equipment.
Implementation Method 1
The liquid is chosen such that it expands upon freezing
Implementation Method 2
the liquid expands upon freezing
Implementation Method 3
two reactants that combine to produce a pigment
Data Source
AI summary
A system and method for indication of temperature exposures beyond a set of predetermined limits employs the salts of weak acid-strong base or of a strong acid-weak base compound as reactants. A device includes a housing and capsule. A first reactant and a liquid are included within the capsule. The liquid is chosen such that it expands upon freezing. The capsule is sized such that when the liquid freezes and expands, the capsule fractures. A second reactant is provided within the housing. The location of the second reactant and the method of attaching (if any) the second reactant to the housing may take various forms. When the liquid within the capsule freezes, it expands and fractures the capsule. Upon thawing, the reactant within the capsule escapes and mixes with the reactant located outside the capsule. A second embodiment is a timetemperature indicator.