Selective Membrane Gas Control for Perishable Produce Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for controlling gas composition in containers for perishable goods face challenges due to instability and inefficiency, particularly with carbon dioxide removal, leading to difficulties in maintaining optimal oxygen and nitrogen levels, which affects the storage life of produce during transportation.
Innovation Solution
A method involving a selective membrane element that draws carbon dioxide from the container at a higher rate than oxygen and nitrogen, with pressure measurement and air introduction to control gas composition, utilizing a pressure-responsive system to estimate air leak flow and adjust gas flow rates to maintain desired levels, eliminating the need for carbon dioxide absorbing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional carbon dioxide absorbing materials are used to remove CO2 from the container, then carbon dioxide levels are reduced, but the device complexity and cost increase due to monitoring equipment and control systems
Solution Approach 1:
The patent extracts carbon dioxide from the container atmosphere by passing the gas mixture through a selective membrane that allows CO2 to permeate through while retaining other gases. This extraction method replaces conventional absorbing materials and eliminates the need for complex monitoring equipment, as the membrane passively separates CO2 based on its selective permeability properties
Solution Approach 2:
The patent employs inexpensive, moderately selective membranes that can be easily replaced rather than using expensive, highly selective membranes that require complex monitoring and control systems. The low cost of these membranes allows for simple implementation without sophisticated equipment, aligning with the principle of using cheap, replaceable components to achieve the desired gas separation function
2Manufacturing precision
If highly selective carbon dioxide membranes are used to maintain gas composition, then gas control precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent deliberately chooses inexpensive, moderately selective membranes over expensive, highly selective membranes. The simple membrane system provides sufficient gas composition control for perishable goods storage without requiring complex supporting equipment, monitoring systems, or sophisticated control mechanisms, thereby achieving acceptable precision with minimal device complexity
Solution Approach 2:
The patent changes the selectivity parameter of the membrane from high to moderate levels. By accepting moderately selective membranes with lower CO2 selectivity, the system eliminates the need for complex monitoring and control equipment, achieving a balance where sufficient gas composition control is obtained through the membrane's inherent separation capability without additional complexity
3Stability of the object's composition
If oxygen monitoring and air admission control are implemented, then oxygen level stability is improved, but the device complexity increases
Solution Approach 1:
The patent removes the need for oxygen monitoring and active control by extracting carbon dioxide through the selective membrane. This passive CO2 removal allows oxygen levels to stabilize naturally through the container's existing air leaks and gas exchange, eliminating complex oxygen monitoring and admission control systems while maintaining stable oxygen levels
Solution Approach 2:
The system allows the container atmosphere to self-regulate oxygen levels through natural processes. The selective membrane passively manages CO2 levels, and the container's existing air leakage provides automatic oxygen replenishment, creating a self-balancing system that maintains stable gas composition without active monitoring or control mechanisms
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 approach provides a stable and controlled environment within the container, extending the storage life of perishable goods by maintaining optimal gas ratios, reducing the need for costly CO2 monitoring equipment and utilizing low-cost, moderately selective membranes for effective gas control.
Implementation Method 1
a selective membrane element that draws carbon dioxide from the container at a higher rate than oxygen and nitrogen
Implementation Method 2
Only certain membranes are useful in providing required permeability to some gases over other gases
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A method of controlling gas composition within a container containing respiring produce is described. The container includes at least one gas outlet and at least one gas inlet and the method includes the steps of; drawing a selected gas from within the container through a selective membrane element and through the at least one gas outlet; detecting ambient pressure inside the container; and introducing ambient air under selected control conditions from outside the container into the container through the at least one gas inlet in response to the detected ambient pressure to control the relative composition of gases inside the container.