Aircraft Galley Chiller Bypass Flap for Airflow Recirculation
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Solution Overview
Problem
Aircraft galley chilling systems face premature and unscheduled defrost cycles due to the ingestion of warm, moist air when galley food cart bay doors are opened during in-flight operations in hot, humid climates, leading to difficulties in maintaining chilled food at the required temperature and risking food spoilage.
Innovation Solution
An electrically operated bypass flap is integrated into the galley ducting to divert supply duct airflow into the return duct, creating a recirculation loop that prevents unscheduled defrost cycles and maintains chilled food at the set temperature by allowing the chiller unit to function normally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If galley food cart bay doors are opened during in-flight operation, then access to food carts is improved, but warm moist air is ingested into the chiller system causing evaporator freezing
Solution Approach 1:
The bypass damper is pre-positioned to divert warm moist air away from the evaporator before the air can cause freezing. When the bay door is opened, the damper automatically redirects the airflow through the bypass passage, preventing the harmful moisture from reaching the cold evaporator surface and causing ice formation.
Solution Approach 2:
The bypass damper acts as an intermediary device between the warm moist air from the bay door and the cold evaporator. It creates an alternative airflow path that mediates the interaction between these two elements, allowing the bay door to remain open for access while preventing the harmful air from directly contacting the evaporator.
2Reliability
If bypass damper is opened to divert airflow, then evaporator freezing is prevented, but cooling efficiency may be reduced
Solution Approach 1:
The bypass damper is designed to be dynamic rather than static, automatically adjusting its position based on bay door status. When the bay door is closed, the damper allows full airflow to the evaporator for maximum cooling efficiency. When the bay door opens, the damper shifts to divert airflow through the bypass, preventing freezing. This dynamic adjustment optimizes both efficiency and reliability.
3Productivity
If chiller airflow continues normally when bay door is open, then cooling capacity is maintained, but warm moist air causes evaporator freezing
Solution Approach 1:
The airflow path is segmented into two separate channels: the primary path through the evaporator for cooling, and the bypass path for warm moist air when the bay door is open. The bypass damper controls which channel is active, allowing the system to maintain cooling capacity through the evaporator while diverting harmful warm moist air through the alternative bypass channel.
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 effectively prevents the freezing of the evaporator and reduces the risk of food spoilage by maintaining the chilled food at the required temperature, thereby avoiding premature defrost cycles and ensuring continuous operation of the galley air chiller.
Implementation Method 1
diverting the supply duct airflow into the return duct by an electrically operated bypass flap
Implementation Method 2
prevents the freezing of the evaporator and reduces the risk of food spoilage by maintaining the chilled food at the required temperature
Data Source
Figure 1~2
AI summary
A device for reversing chiller airflow in an aircraft galley includes an air bypass port (30) connected between a supply airflow duct (20) and a return airflow duct (28), and an air recirculation bypass flap (32) is movable between a closed position allowing normal airflow circulation through the supply airflow duct (20) and an open position blocking the supply airflow duct (20) and diverting chilled supply airflow to the return airflow duct (28) for recirculation. The air recirculation bypass flap (32) is electrically actuated by a solenoid (34) responsive to a bay door position detector (36).