Defrost Indicator Using Phase Change Liquids for Frozen Food Monitoring
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Solution Overview
Problem
Existing temperature monitoring devices for packaged frozen food are costly, impractical for long-term use in extreme environments, and require battery power, making them unsuitable for ensuring the freshness and preventing spoilage by detecting if the food has been defrosted during transportation or storage.
Innovation Solution
A defrost indicator comprising a body member that changes shape or size in response to temperature changes, featuring an indicia that alters appearance when frozen or defrosted, utilizing liquids with different melting points and biasing members to provide a visible indication of defrosting, which can be easily integrated into packaging for easy deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high/low thermometers are used to monitor temperature, then temperature measurement capability is provided, but cost, size, and complexity increase
Solution Approach 1:
The patent extracts the temperature sensing function from complex electronic thermometers and implements it through a simple thermal response element (such as a bimetallic strip or thermal expansion component) that physically changes state with temperature, eliminating the need for batteries, displays, and electronic circuits while maintaining temperature monitoring capability
Solution Approach 2:
The invention uses inexpensive, simple thermal response elements that can be easily manufactured and disposed of if needed, replacing costly electronic thermometers with a low-cost mechanical or physical indicator that provides sufficient temperature monitoring without requiring power sources or complex electronics
2Measurement precision
If battery operated thermometers are used, then temperature monitoring is enabled, but hazardous materials and long-term power requirements are introduced
Solution Approach 1:
The patent removes the battery and electronic power system from the temperature monitoring device, replacing it with a passive thermal response mechanism that operates solely on temperature differential, thereby eliminating hazardous materials and long-term power requirements while maintaining temperature monitoring functionality
Solution Approach 2:
The thermal response element automatically responds to temperature changes without requiring external power sources, using the temperature differential itself to drive the indication mechanism, making the device self-powered and eliminating the need for batteries or electronic power systems
3Ease of manufacture
If simple indicators are used to show defrosting, then cost and ease of deployment improve, but measurement precision and reliability deteriorate
Solution Approach 1:
The patent utilizes a thermal response element that undergoes a distinct physical parameter change (such as shape, volume, or mechanical position) at a specific temperature threshold, providing a clear and unambiguous indication of defrosting while maintaining simplicity and low cost through the use of basic thermal expansion or bimetallic bending principles
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 provides a low-cost, tamper-resistant, and easy-to-deploy method for determining if packaged frozen food has been defrosted, ensuring freshness and preventing spoilage by using a visible indicia that changes appearance when the food reaches undesirable temperatures.
Implementation Method 1
utilizing liquids with different melting points
Implementation Method 2
when at least a portion of the one or more frozen liquids melt into a liquid
Implementation Method 3
A defrost indicator comprising a body member that changes shape or size in response to temperature changes
Data Source
AI summary
A defrost indicator including: a body member, at least a portion of which is capable of having a restrained shape or size and an unrestrained shape of size; and an indicia disposed on at least one surface of the body member, an appearance of the indicia being different in the restrained shape or size than in the unrestrained shape or size; wherein the body member is restrained into the restrained shape by freezing one or more liquids associated with the body member.