Space Commode Air-Liquid Separation for Lower-Cost Waste Handling
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Solution Overview
Problem
Existing space toilets fail to provide efficient and sanitary waste management systems, with existing systems being excessively expensive and complex, and there is a need for simpler and cheaper solutions that can handle both liquid and gas effluents effectively in space environments.
Innovation Solution
A universal commode system with separate flow paths for air and liquid effluents, using commercial-off-the-shelf motors, a temporary urine storage tank, and a pre-treatment assembly with a COTS pump and tank, along with a controller for optimal chemical dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing space toilet systems are used, then waste management function is provided, but system cost and complexity become excessively high
Solution Approach 1:
The system divides waste management into separate flow paths: one for liquid effluent (urine) and another for gas effluent (air). This segmentation allows each path to be optimized independently with simpler, more cost-effective components rather than requiring a single complex integrated system.
Solution Approach 2:
The air/liquid separator performs multiple functions: it separates liquid from gas effluent, serves as a pretreatment stage, and enables independent processing of different waste streams. This multi-functionality reduces the need for separate dedicated components for each function.
2Reliability
If existing space toilet systems are used, then waste management function is provided, but system cost becomes excessively high
Solution Approach 1:
The system employs commercial-off-the-shelf (COTS) components including motors, pumps, and filters that are readily available, cost-effective, and can be easily replaced. This approach avoids the need for expensive custom-built space-rated components while maintaining adequate functionality.
Solution Approach 2:
The system extracts and treats liquid effluent separately from the main waste stream using an air/liquid separator and dose pump. This extraction allows targeted treatment of urine with pretreatment liquid, reducing the burden on the overall waste management system and lowering total system cost.
3Device complexity
If single motor system is used, then system simplicity is maintained, but power consumption increases
Solution Approach 1:
The motor system is segmented into two independent motors: one driving the air/liquid separator and another driving the fan. This segmentation allows each motor to be optimized for its specific function and operate only when needed, reducing total power consumption compared to a single motor that would need to handle all functions continuously.
Solution Approach 2:
The system transitions from a static single-motor design to a dynamic multi-motor configuration where motors can be independently controlled and activated based on operational requirements. This dynamic approach optimizes energy usage by running only the necessary motors at any given time.
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
Simplifies the system's cost and complexity, minimizes power consumption, and provides flexible urine storage and treatment, while maintaining sanitary conditions in space environments.
Implementation Method 1
a first motor coupled to the air/liquid separator and configured to drive an operation of the air/liquid separator to separate air, liquid and pretreatment liquid flowing into the air/liquid separator
Implementation Method 2
a second motor independent of the first motor, coupled to the fan and configured to drive an operation of the fan to draw air out of the air/liquid separator and the commode line
Implementation Method 3
a dose pump configured to pump a quantity of the pretreatment liquid from the pretreatment liquid source to the urine line
Data Source
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AI summary
A universal commode system (UCS) is provided and includes an air/liquid separator (110), a urine line (120) connected to the air/liquid separator (110), a fan (130), a cabin air return line (140) connected to the air/liquid separator (110) and to the fan (130), a commode line (150) connected to the cabin air return line (140), a first motor (160) coupled to the air/liquid separator (110) and configured to drive an operation of the air/liquid separator (110) and a second motor (170) independent of the first motor (160), coupled to the fan (130) and configured to drive an operation of the fan (130).