Membrane-Lined Waste Drying Bag for Microgravity Separation
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Solution Overview
Problem
Human waste disposal in spacecraft environments is challenging due to the absence of gravity, requiring separate methods for liquid and solid waste disposal, and existing solutions are bulky and not user-friendly, especially for small spacecraft like the Apollo capsule or CEV.
Innovation Solution
A soft-sided, membrane-lined container or bag that uses air flow and vacuum to move and vaporize waste materials, separating liquids from solids, and optionally reconstituting vaporized liquids, allowing for efficient drying and storage of waste without relying on gravity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional toilets with water flow and gravity are used, then liquid and solid waste can be disposed of effectively, but they require gravity and are bulky and heavy
Solution Approach 1:
The waste disposal system is segmented into separate collection bags for liquid waste and solid waste, each with dedicated vacuum ports and membrane structures. This allows independent processing of different waste types without requiring a bulky integrated system, reducing overall weight while maintaining effectiveness.
Solution Approach 2:
The invention replaces gravity-dependent water flow with vacuum-driven air flow to move waste materials. The vacuum source creates pressure differentials that propel liquid waste through membranes and solid waste through collection bags, eliminating the need for gravity and reducing water requirements.
2Reliability
If Apollo bags with adhesive flanges and finger cots are used, then solid waste can be collected in microgravity, but they are not user-friendly
Solution Approach 1:
The system employs automatic vacuum activation and self-sealing mechanisms. When waste is deposited, the vacuum automatically engages to draw material into collection bags, and membranes automatically seal around waste. This eliminates the need for complex manual operations like finger cots and adhesive flanges, improving user-friendliness while maintaining microgravity effectiveness.
Solution Approach 2:
Flexible membranes act as intermediaries between the user and the vacuum system. The membranes can be manipulated easily by users to deposit waste, then automatically seal and connect to vacuum ports, providing a simple interface that maintains reliable waste collection without requiring complex user actions.
3Loss of substance
If vacuum drying is applied to waste, then liquids and vapors can be separated from solid waste, but energy is required for vaporization
Solution Approach 1:
The system utilizes phase transition of water from liquid to vapor through vacuum-induced evaporation. The vacuum source reduces pressure in the collection bag, causing liquid waste to vaporize at lower temperatures. This separates liquids from solids without requiring high-energy heating, as the phase change occurs naturally under reduced pressure conditions.
Solution Approach 2:
The vacuum system dynamically adjusts pressure parameters to control the drying process. By varying the vacuum level, the system can optimize energy consumption - using higher vacuum for rapid drying when needed, and lower vacuum for energy-efficient maintenance drying, thereby reducing overall energy requirements while achieving effective separation.
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 simplifies waste collection, reduces disposal costs, and provides clean, compacted, and dried waste, suitable for various hazardous or medical waste types, making it user-friendly and suitable for small spacecraft.
Implementation Method 1
a vacuum source, having an associated pressure differentials capable of creating a vacuum within the bag
Implementation Method 2
pressure differentials capable of creating a vacuum within the bag
Implementation Method 3
vaporizes part or all of the liquid waste by creating a modest vacuum within the bag
Implementation Method 4
moves the original vapor and the vaporized liquid waste across the membrane, thereby partly or fully drying the solid waste within the bag
Data Source
AI summary
Method and system for processing waste from human activities, including solids, liquids and vapors. A fluid-impermeable bag, lined with a liquid-impermeable but vapor-permeable membrane, defining an inner bag, is provided. A vacuum force is provided to extract vapors so that the waste is moved toward a selected region in the inner bag, extracted vapors, including the waste vapors and vaporized portions of the waste liquids are transported across the membrane, and most or all of the solids remain within the liner. Extracted vapors are filtered, and sanitized components thereof are isolated and optionally stored. The solids remaining within the liner are optionally dried and isolated for ultimate disposal.