Personal Breathing Zone Laminar Airflow Without Drafts
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Solution Overview
Problem
Existing devices that provide a purified personal breathing zone during sleep, such as those using HEPA filtration, often suffer from uncomfortable airflow drafts and dehydration due to high velocities of forced-blown air, which can lead to turbulent mixing of contaminated ambient air, and are bulky or noisy, especially when requiring two separate air streams for temperature control.
Innovation Solution
A Temperature Controlled Laminar Airflow (TLA) system that uses a single filtered air stream with adjustable temperature, facilitated by a thermoelectric cooler with reversible polarity, to maintain an optimal air-temperature difference between the supplied air and ambient air, ensuring a descending laminar flow that displaces body convection currents without excessive velocity, thus minimizing drafts and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If forced-blown air is used to provide a purified personal breathing zone, then air purification is achieved, but uncomfortable drafts and dehydration occur due to high air flow velocity
Solution Approach 1:
The patent changes the velocity parameter of the air flow by using gravity-induced laminar flow instead of forced-blown high velocity flow. The air temperature difference between supply air and ambient air controls the descent velocity, maintaining it below 0.1 m/s to avoid uncomfortable drafts while still providing effective air purification through the HEPA filter.
Solution Approach 2:
The patent replaces the mechanical forced-blown system with a gravity-induced natural convection system. Instead of using high-power fans to force air flow, the system uses the density difference caused by temperature variation to induce laminar downward flow, eliminating the mechanical turbulence and high velocity associated with forced ventilation.
2Adaptability or versatility
If two separate air streams are used for temperature control, then precise temperature control is achieved, but device complexity and noise increase
Solution Approach 1:
The patent merges the temperature control function into a single air stream system. Instead of maintaining two separate air streams with different temperatures, the system uses one filtered air stream whose temperature is adjusted to create the appropriate density difference for gravity-induced laminar flow, thereby reducing device complexity while maintaining effective temperature and flow control.
3Stability of the object's composition
If high velocity air flow is used to maintain laminar flow, then laminar flow structure is maintained, but fan noise and energy consumption increase
Solution Approach 1:
The patent replaces the mechanical energy input from high-speed fans with gravitational potential energy. The laminar flow structure is maintained not by high velocity forced flow but by the gentle descent of cooled, denser air under gravity. This substitution dramatically reduces fan noise and energy consumption while preserving the laminar flow characteristics essential for avoiding turbulent mixing.
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 TLA system effectively maintains a controlled personal breathing zone with minimal noise and discomfort by ensuring a stable, descending laminar airflow that displaces body convection currents while avoiding drafts, using a single air stream and reducing fan noise, thus enhancing user compliance and comfort.
Implementation Method 1
Temperature control is facilitated by a thermoelectric cooler (TEC) using the Peltier effect with reversible polarity
Implementation Method 2
A substantially laminar flow of filtered, colder air, having a higher density than ambient air descends slowly, enveloping the breathing zone of a sleeping person
Implementation Method 3
a laminar flow is induced by an air-temperature difference between supply air and ambient air at the point of care
Data Source
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AI summary
Methods and devices are provided whereby a controlled personal breathing zone is maintained using temperature controlled laminar air flow (TLA) of filtered air. A substantially laminar, descending flow of filtered air is maintained with a velocity determined by the air-temperature difference between the supplied air and the ambient air at the level of the personal breathing zone. The air-temperature of the filtered supply air can be carefully adjusted to maintain the velocity-determining difference in air-temperature within the optimum range of 0.3 to 1 0C. Thus being able to at the same time displace body convection and achieve comfort.