Self-heating container for pre-cooked food
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Solution Overview
Problem
Self-heating containers for pre-cooked food often waste heat due to direct contact between the exothermic reaction vessel and the outer receptacle, leading to inefficient heating of the food vessel and increased risk of burns.
Innovation Solution
The design features a lower vessel with calcium oxide and water housed inside an outer receptacle, where the upper vessel is fixed to minimize contact surfaces and maximize heat exposure, using recessed and projecting sectors to contain heat and an adhesive rim for stable positioning, ensuring efficient heat transfer to the food vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lower vessel containing exothermic reaction products is allowed to contact the outer receptacle for structural support, then the container structure is simplified and easier to manufacture, but heat is wasted by heating the outer receptacle instead of the food vessel, and burn risk increases
Solution Approach 1:
The patent introduces an intermediate insulating layer between the lower vessel (containing exothermic reaction products) and the outer receptacle. This intermediary prevents direct thermal contact, stopping heat from being wasted on heating the outer receptacle while maintaining the structural support function. The insulating layer acts as a thermal barrier that allows mechanical support without thermal transfer.
Solution Approach 2:
The patent segments the contact surface between the lower vessel and outer receptacle by providing discrete support points or isolated contact areas rather than continuous contact. This segmentation reduces the total thermal contact area, minimizing heat loss to the outer receptacle while still providing sufficient structural support for the container assembly.
2Device complexity
If the upper vessel containing food contacts the lower vessel only at the base, then the structure is simple, but heat transfer efficiency is reduced and most heat is lost to the exterior
Solution Approach 1:
The patent extends the heat transfer interface from a single-point or single-area base contact to a multi-dimensional contact system. The upper vessel is designed with extended side surfaces or protrusions that contact the lower vessel along vertical surfaces, adding dimensional extent to the thermal interface. This increases the effective heat transfer area without significantly complicating the overall structure.
Solution Approach 2:
The patent merges the heat transfer function with the structural support function by designing the contact surfaces between upper and lower vessels to serve both purposes. The same surfaces that provide structural stability and positioning also function as thermal transfer pathways, combining multiple functions into a unified structural arrangement that improves heating efficiency without adding separate components.
3Volume of moving object
If the upper vessel fits inside the receptacle with side surface contact, then the container is compact, but the contact between upper vessel and lower vessel is limited to the base only
Solution Approach 1:
The patent employs curved or contoured contact surfaces between the upper and lower vessels, replacing flat base-only contact with curved surfaces that wrap around portions of the vessels. These curved geometries increase the surface area available for thermal contact while maintaining a compact overall container volume. The curved surfaces allow greater thermal interface area within the same spatial envelope.
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 configuration optimizes heat utilization, reduces heat loss, and minimizes the risk of burns by ensuring the upper vessel is directly exposed to the heat generated, enhancing the heating efficiency of pre-cooked food.
Implementation Method 1
a lower vessel carrying calcium oxide, a water bag and a striker to break the bag and mix the water with the calcium oxide causing an exothermic reaction
Data Source
AI summary
This container comprises: an outer receptacle containing a lower vessel carrying calcium oxide, a water bag and a striker to break the bag and mix the water with the calcium oxide causing an exothermic reaction; and an upper vessel carrying the pre-cooked food and fixed on the lower vessel. The outer receptacle has on its side surface: recessed sectors and projecting sectors forming hollow side chambers between the lower container and the side surface of the outer receptacle and, in correspondence with the upper end of the mentioned vertical sectors, a perimetral step for the linear support of a projecting rim defined in the upper opening of the lower vessel. The upper vessel comprises a perimetral step in an area close to its upper end for its support and fixing by means of an adhesive on the projecting upper rim of the lower vessel.