Fold-Barrier Time-Temperature Indicator for Accurate Cold-Chain Timing
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Solution Overview
Problem
Blister-type time-temperature indicators require user-initiated activation, which is inconvenient when the indicator fluid solidifies during storage, necessitating heating to melt the fluid and rupture the blister, leading to potential pre-activation and inaccurate time lapse measurement.
Innovation Solution
A blister-type time-temperature indicator is designed to be activated before cold storage with a reservoir that contains liquid indicator fluid, which solidifies during storage, allowing for activation by rupturing a weak seal with moderate finger pressure, preventing premature liquid migration and enabling immediate use without heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the device is activated by heating to melt the solidified indicator fluid, then the fluid can migrate and the device can be activated, but this leads to potential pre-activation and inaccurate time lapse measurement
Solution Approach 1:
The device is pre-activated during manufacturing by rupturing the seal while the indicator fluid is in liquid state, but the migration path is blocked by a fold in the migration medium. This preliminary activation allows the device to be in ready state without actual fluid migration occurring during storage
Solution Approach 2:
The migration path is segmented into two parts: the reservoir area and the migration medium area. A fold in the migration medium creates a physical barrier that separates these areas, preventing fluid migration while allowing the device to remain activated and ready for use
2Measurement precision
If the device requires user-initiated activation, then accurate time measurement can be ensured, but this creates inconvenience when the indicator fluid solidifies during storage
Solution Approach 1:
The device is pre-activated during manufacturing by rupturing the seal, eliminating the need for user activation. The fold in the migration medium prevents actual fluid migration until the device is removed from cold storage and the fluid melts
Solution Approach 2:
The device automatically activates itself during the manufacturing process without requiring user intervention. The system uses its own structure (the fold in the migration medium) to prevent premature fluid migration while maintaining activation readiness
3Ease of operation
If the indicator fluid is kept liquid at conventional ambient temperatures, then the device can be easily activated, but the device must be manufactured and delivered below the threshold temperature to prevent premature migration
Solution Approach 1:
The seal is ruptured during manufacturing while the fluid is liquid, but the fold in the migration medium prevents actual migration. This allows the device to be manufactured and delivered in liquid state without premature activation
Solution Approach 2:
The fold in the migration medium acts as an intermediary barrier that prevents direct contact between the indicator fluid and the migration path. This allows the fluid to be in liquid state during manufacturing and delivery without causing premature migration
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 device can be shipped in an activated state, preventing pre-activation and ensuring accurate elapsed time measurement by allowing the indicator fluid to migrate only when the product reaches the threshold temperature, eliminating the need for user-initiated activation and reducing inconvenience.
Implementation Method 1
a migration medium arranged with respect to the reservoir and the barrier, so that when the seal is ruptured the liquid reaches the migration medium and migrates through it producing a colour change therein
Implementation Method 2
having a reservoir that contains indicator fluid that solidifies when the product to which it is attached is stored, but which liquefies when removed from cold storage prior to use
Data Source
AI summary
A time temperature indicator for measuring elapsed time after reaching a threshold temperature includes a reservoir containing an indicator fluid that may be solid below the threshold temperature and that liquefies above the threshold temperature. Activation enables a flow of liquid from the reservoir to reach a migration medium so that when the temperature of the indicator exceeds the threshold temperature after activation liquid migrates through the migration medium producing a colour change therein. A narrow passage is foldable along and parallel to a longitudinal axis thereof so as to form a barrier to liquid migration when the passage is folded while permitting liquid migration through the passage when the passage is unfolded. A micro-fluid valve may be likewise constructed for regulating a flow of liquid between an inlet and an outlet coupled by a narrow passage foldable along and parallel to a longitudinal axis thereof.