Shear-Activated Reactant Pouch With Gas-Venting Compartment
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Solution Overview
Problem
Existing pouch designs for internal mixture of segregated reactants require significant force and user expertise to activate, often resulting in incomplete mixing and are prone to premature seal failure, especially during shipping and storage, and lack a venting system to handle reaction gases, limiting the types of reactants that can be used.
Innovation Solution
A pouch design featuring an outer containment envelope with a sealed reactant compartment and a middle shear strip that, when pulled, creates shear lines to open the compartment, allowing easy activation without strength or knowledge, and includes a permeable second reactant compartment with a slit for gas escape, preventing ballooning and explosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a frangible seal is used to separate reactants, then the seal can be broken with compression force to allow mixing, but the seal may fail prematurely during shipping and storage or require excessive force to activate
Solution Approach 1:
The seal is divided into multiple segments: an inner frangible seal for reactant release and an outer perimeter seal for containment. The inner seal is designed to fail at a lower force threshold to enable easy activation, while the outer seal maintains higher strength to prevent premature failure during shipping and storage. This segmentation allows each seal to have optimized properties for its specific function.
Solution Approach 2:
Different regions of the pouch have different seal strengths tailored to their specific requirements. The inner seal region has lower strength to facilitate easy breaking with minimal compression force, while the outer perimeter seal has higher strength to maintain integrity during handling and transport. This local differentiation of seal properties resolves the contradiction between ease of activation and reliability.
2Ease of operation
If the dividing seal is made weaker to facilitate user activation, then less force is required to break it, but the seal may fail prematurely due to outside forces during shipping and storage
Solution Approach 1:
The sealing system is segmented into an inner frangible seal and an outer perimeter seal. The inner seal is intentionally made weaker with lower bond strength to require minimal force for activation, making it easy for all users to operate. The outer perimeter seal is made stronger to resist external forces during shipping, storage, and handling, preventing premature failure while allowing the inner seal to remain easily breakable.
3Productivity
If compression force is applied to rupture the inner seal, then the reactants can mix, but the perimeter seals or film may burst first creating leaks and failed activation
Solution Approach 1:
The pouch structure incorporates localized strength variations: the outer perimeter seals and film are designed with higher strength properties to withstand compression forces during activation, while the inner seal region is designed with lower strength to fail first. This local differentiation ensures that when compression force is applied, the inner seal ruptures to allow mixing while the stronger outer seals maintain integrity and prevent leaks.
4Ease of operation
If a weaker seal is created to make activation easier, then less pressure from the user is needed, but the seal will fail during manufacturing control and production runs
Solution Approach 1:
The sealing system is divided into inner and outer seals with different strength specifications. The inner seal is designed with lower strength parameters to enable easy user activation without requiring significant force. The outer perimeter seal is designed with higher strength parameters that are easier to control and maintain consistency during manufacturing. This segmentation allows the manufacturing process to focus on producing consistent outer seals while the inner seal remains optimized for easy activation.
5Reliability
If the pouch is sealed tightly to prevent leakage, then reactants remain segregated, but gases generated by reaction cannot escape causing ballooning and dangerous failure
Solution Approach 1:
The pouch incorporates a porous or permeable membrane within the sealed structure that allows gases generated by the chemical reaction to pass through and escape. The membrane has pore sizes that permit gas molecules to pass while maintaining the liquid-tight seal necessary to keep reactants segregated before activation and prevent leakage during handling. This resolves the contradiction by providing a pathway for gas escape while maintaining seal integrity.
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
Enables easy and complete mixing of reactants with minimal force, reduces operator dependency, and allows the use of a wider range of reactants by venting gases, enhancing safety and reliability.
Implementation Method 1
Pulling on the strip causes the shear line to lengthen until the sealed reactant compartment is shorn open
Implementation Method 2
The second reactant compartment may form a barrier that prevents the first reactant from escaping through the slit in the outer containment envelope, but which may permit gasses to escape
Data Source
AI summary
A pouch for internal mixture of segregated reactants includes an outer containment envelope with a sealed reactant compartment inside. A middle shear strip and two outer strips, together defining two shear lines, are connected to the reactant compartment. The outer strips are folded under the reactant compartment with their tips anchored to the containment envelope. The middle strip extends away from the reactant compartment and through a slit in the containment envelope. Pulling on the middle strip causes the shear lines to lengthen until the reactant compartment is shorn open to release a reactant. A permeable second reactant compartment containing a second reactant may also be disposed inside the containment envelope, and may include a slit through which the middle strip passes. The reaction in the pouch may be exothermic and the pouch may be applied to any object to be heated such as a wet wipes dispenser.