Method and system for managing the grey water in an aircraft
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Solution Overview
Problem
Existing grey-water management systems in aircraft toilets face issues with energy efficiency, weight, maintenance requirements, and sensitivity to cavitation and pollution, particularly due to the use of rotodynamic and Venturi pumps which are prone to mechanical damage and clogging from foreign bodies.
Innovation Solution
A diaphragm pump with an undulating diaphragm is used, actuated by an electromagnetic linear actuator, which is self-priming and resistant to cavitation and pollution, allowing for efficient wastewater removal from retention tanks without rotary parts, thus reducing maintenance needs and handling varying waste sizes and foreign bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotodynamic pumps (centrifugal or turbine pumps) are used in grey-water management systems, then the system can achieve continuous pumping operation, but the energy efficiency is poor (30%-70%), the overall volume and weight are large, and there is considerable wear on rotating parts requiring frequent maintenance
Solution Approach 1:
The pump is divided into multiple diaphragm chambers that operate in sequence, with each chamber performing a complete pumping cycle independently. This segmentation allows continuous pumping operation while each individual diaphragm chamber remains compact and efficient
Solution Approach 2:
The diaphragms undergo periodic oscillation between expansion and contraction phases, creating alternating suction and discharge cycles. This periodic action enables continuous flow while maintaining high instantaneous efficiency during each cycle
2Productivity
If rotodynamic pumps are used in grey-water management systems, then the system can achieve pumping capability, but the overall volume and weight are large
Solution Approach 1:
The diaphragms are made of flexible thin film materials that can withstand repeated oscillation while maintaining structural integrity. This flexibility allows the pump to achieve pumping capability with minimal material mass, significantly reducing overall weight compared to rigid rotodynamic pump constructions
Solution Approach 2:
The heavy rotating components (impellers, shafts, bearings) are completely removed from the system. Only the lightweight flexible diaphragms remain as moving parts, extracting the essential pumping function from the mass-intensive rotodynamic mechanism
3Productivity
If rotodynamic pumps are used in grey-water management systems, then the system can achieve pumping operation, but there is considerable wear on rotating parts requiring frequent maintenance
Solution Approach 1:
All rotating parts that are subject to wear (impellers, shafts, bearings, seals) are completely removed from the system. The pump operates using only reciprocating diaphragm motion, eliminating the wear mechanisms inherent in rotodynamic designs and enabling long-term operation without maintenance
Solution Approach 2:
The diaphragms are designed as simple, inexpensive replacement parts that can be easily swapped if needed. Their simple construction and lack of complex machining make them far cheaper and easier to replace than worn rotodynamic components
4Productivity
If rotodynamic pumps are used in grey-water management systems, then the system can achieve pumping capability, but the pumps are sensitive to the phenomenon of cavitation which can destroy the machine
Solution Approach 1:
The diaphragms create periodic pressure variations that gently draw fluid through the pump, avoiding the high-velocity regions and sudden pressure drops that cause cavitation in rotodynamic pumps. This periodic suction-discharge cycle maintains reliable operation even with varying fluid conditions
5Productivity
If Venturi pumps are used in grey-water management systems, then the system can achieve pumping operation using the Venturi effect, but another type of pump is required to generate drive pressure increasing overall weight, and energy efficiency is very low (10%-25%)
Solution Approach 1:
The diaphragm pump generates its own drive pressure through the mechanical oscillation of the diaphragms, eliminating the need for a separate drive pump. The oscillating diaphragms directly create the pressure differential needed for pumping, achieving self-sufficiency and high energy efficiency
6Productivity
If prior art pumps are used in grey-water management systems, then the system can achieve wastewater removal, but the pumps are sensitive to pollution in the grey water causing blocking or clogging when waste or foreign bodies are present
Solution Approach 1:
The pump channels are segmented into multiple pathways with sufficient spacing, preventing foreign bodies from blocking the entire flow path. Particles and waste can pass through the gaps between diaphragms and channel walls without causing system failure
Solution Approach 2:
The flexible diaphragms can deform to accommodate foreign bodies and irregularities in the fluid stream, preventing clogging while maintaining pumping action. The flexibility allows the pump to handle polluted grey water with solid particles without the rigid blockage problems of traditional pumps
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 diaphragm pump system achieves low maintenance, high energy efficiency, and resistance to cavitation and pollution, enabling reliable operation under flight conditions and handling dirty or particulate-rich grey water effectively.
Implementation Method 1
the diaphragm of the pump being suitable for undulating, under the action of actuation means, so as to remove said wastewater present in the retention tank through the inlet pipe of the pump to an outlet pipe of the pump
Implementation Method 2
A diaphragm pump with an undulating diaphragm is used, actuated by an electromagnetic linear actuator
Data Source
AI summary
A method of removing wastewater contained in a water retention tank of a grey-water management system for an aircraft toilet. The method removes the wastewater via a diaphragm pump having an undulating diaphragm. The diaphragm pump includes an inlet pipe connected to the retention tank, the diaphragm of the pump is actuated by electromagnetic or magnetic actuation so as to remove wastewater present in the retention tank through the inlet pipe of the pump to an outlet pipe of the pump.