Centrifugal Air Trap for Microgravity IV Fluid Delivery
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Solution Overview
Problem
In microgravity environments, existing air trap devices for intravenous fluid delivery systems are ineffective due to reliance on gravity for air bubble exclusion, leading to health risks from air embolisms as they cannot handle the high pressure-driven flow rates and large air volumes encountered in spaceflight.
Innovation Solution
An inline microgravity air trap device with a centrifugal force-based design that uses a cylindrical air trap chamber and a hydrophobic filter to separate air bubbles from fluids, allowing air to escape through a gas egress opening while fluid continues to be delivered, effectively managing high flow rates and large air volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gravity-based air separation is used in IV fluid delivery, then air bubbles can be excluded under normal terrestrial conditions, but the system becomes ineffective in microgravity environments where air embolism risks cannot be prevented
Solution Approach 1:
The patent replaces the gravity-based mechanical separation system with a centrifugal force-based system. The air trap chamber is designed to rotate or receive rotational fluid flow, generating centrifugal force that separates air bubbles from IV fluid regardless of gravitational conditions. This substitution allows the same device to function effectively both on Earth and in microgravity environments during spaceflight.
Solution Approach 2:
The invention changes the fundamental separation parameter from gravitational force to centrifugal force. By designing the air trap chamber with specific geometric features (tangential inlet, curved flow path, central collection region) that generate and utilize centrifugal effects, the system achieves air-liquid separation based on rotational dynamics rather than gravitational buoyancy, enabling operation across different gravity regimes.
2Ease of operation
If pressure bags are used to deliver IV fluid in microgravity, then fluid delivery can be achieved, but excessive air in the tubing cannot be removed
Solution Approach 1:
The patent merges two previously separate functions into a single integrated device: fluid delivery (via pressure bag connection) and air removal (via centrifugal separation). The air trap chamber receives pressurized fluid from the pressure bag while simultaneously using the fluid's kinetic energy and chamber rotation to generate centrifugal force for air separation. This combination allows both functions to operate together without requiring separate air removal equipment.
Solution Approach 2:
The air trap chamber acts as an intermediary device between the pressure bag and the patient. It receives fluid under pressure from the bag, performs centrifugal air separation, and delivers the air-free fluid to the patient. The chamber's design with tangential inlet and central collection region creates a controlled environment where air bubbles are separated and trapped before they can reach the patient, mediating the harmful effect of pressurized fluid delivery.
3Reliability
If terrestrial air filters are used for IV fluids, then small air bubbles can be filtered, but large volumes of air encountered in microgravity cannot be handled
Solution Approach 1:
The patent segments the air removal function into two distinct mechanisms: (1) centrifugal separation in the air trap chamber for handling large volumes of air, and (2) hydrophobic filter for removing remaining small air bubbles. The centrifugal field separates bulk air from fluid in the rotating chamber, while the hydrophobic filter at the outlet removes residual small bubbles. This segmentation allows the system to handle both large and small air volumes effectively.
Solution Approach 2:
The invention utilizes pneumatic principles through the hydrophobic filter, which relies on surface tension and contact angle properties to prevent air passage while allowing fluid flow. The filter's porous structure with hydrophobic coating creates capillary pressure that blocks air bubbles based on their size and the applied pressure differential. This pneumatic mechanism complements the centrifugal separation, enabling the system to handle varying air volumes and sizes that single-mechanism filters cannot manage.
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 device successfully removes air bubbles from IV fluids in microgravity conditions, preventing air embolisms and ensuring safe fluid delivery by leveraging centrifugal force to separate gases from liquids, outperforming commercial filters at higher pressures and flow rates.
Implementation Method 1
The chamber is formed to direct fluid from the pressurized fluid supply to accelerate centrifugally around the filter, forcing gas contained in the fluid to pass through the filter into the interior of the tube
Implementation Method 2
a hydrophobic filter to separate air bubbles from fluids, allowing air to escape through a gas egress opening while fluid continues to be delivered
Data Source
AI summary
An inline microgravity air trap device includes an elongate air trap chamber, the air trap chamber having a blind end, an opposite air outlet end containing a gas egress opening, a fluid inlet port connecting to a pressurized fluid supply, a fluid outlet port connecting the air trap chamber to a fluid delivery destination, a filter forming a tube having an interior, a first end at the blind end of the air trap chamber and a second end at the gas egress opening, and a structural insert in the interior of the tube, having a first insert end located at the blind end, and a second insert end located the air outlet end, where the chamber is formed to direct fluid from the pressurized fluid supply to accelerate centrifugally around the filter, forcing gas contained in the fluid to pass through the filter into the interior of the tube.