April 13, 2021, 04:01:33 AM
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Topic: Workplace air cleaner  (Read 76 times)

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Offline Enthalpy

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Workplace air cleaner
« on: March 08, 2021, 07:26:40 AM »
Hello everyone and everybody!

Sars-Cov2 allegedly propagates through air as an aerosol. I propose to flow air between many sheets that catch the droplets falling on them.

A liquid wetting the sheets shall destroy the viruses and evacuate the residues as the slowly rotating sheets dive in a tank. The liquid's flamability, toxicity, odour, vapour pressure, foam... matter. Maybe some soap or nonvolatile alcohol fit. The sketched example lets air flow radially to the hollow centre where a non-displayed fan extracts it. The sheets should remove most dust before it reaches the fan, and the liquid wash the dust away, so maintenance would mainly replace the liquid.

The sheets are tilted so they can pass through water and dust falls on them. This works also at the sides and lower parts of the sheets (because the air flow is parallel to the sheets), advantage over a cylindrical stack of frustums. A few (not displayed) combs can hold the sheets. Sketch appended here under.

The example dimensions are not optimized and not displayed on scale. D=10µm droplets fall through air with 2.9mm/s, so 22.5° tilt lets cross 1mm sheet separation in 0.9s, while Brownian motion wouldn't suffice
https://en.wikipedia.org/wiki/Stokes%27_law - https://en.wikipedia.org/wiki/Brownian_motion
dR=30mm allow 33mm/s between the sheets. 100mm cumulated separation, D=100mm to 250mm, and estimated 3/4 turn exposed to air let 1.4L/s flow through. This exceeds a person's peak inspiration during moderate activity (cashier, computer work...), so the cleaned air makes a bubble around the person's head. A single small device processes 80m3 in a 16 hour night, that's an individual office.

Operation is very gentle and silent. Air is extracted with only 50mm/s on D=190mm. Laminar flow drops 0.2Pa at the sheets, so the fan needs >0.6m/s near its hub, for instance 150rpm. Slow sheets are quieter, but if they give the rotation speed, then a static flow straightener might replace the fan, possibly with a centrifugal flow, hi Tesla.

Operation needs very little power: 0.3mW air flow between the sheets, 2µW air acceleration, maybe 0.2mW liquid movement. Losses and decorative Leds consume more. A Usb port, a battery, an AC adapter suffice.

Marc Schaefer, aka Enthalpy

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